PURSE Proceedings 2007 Part II

UNIVERSITY OF PERADENIYA SRI LANKA

PROCEEDINGS OF THE PERADENIYA UNIVERSITY RESEARCH SESSIONS

PURSE 2007

Volume 12 Part II - Engineering, Physical Sciences, Humanities and Social Sciences

Editorial Board

Prof. K.D.W. Nandalal Faculty of Engineering

Chief Editor

Prof. C. Sivayoganathan Faculty of Agriculture

Prof. V. Thevanesam

Faculty of Allied Health Sciences

Dr. D.K. Jayaratne Faculty of Arts

Dr. M.A.M. Sitheeque

Faculty of Dental Sciences

Dr. S.D. Dewasurendra Faculty of Engineering

Prof. R. Sivakanesan Faculty of Medicine

Prof. A.D.L.C. Perera

Faculty of Science

Dr. H.B.S. Ariyaratne Faculty of Veterinary Medicine and Animal Science

30th November 2007

UNIVERSITY OF PERADENIYA PROCEEDINGS OF THE PERADENIYA UNIVERSITY RESEARCH SESSIONS PURSE – 2007

ISSN-1391-4111 ISBN-978-955-589-101-1

PUBLISHED BY THE UNIVERSITY OF PERADENIYA

PERADENIYA, SRI LANKA

Printed at the Printing Unit, Faculty of Science, University of Peradeniya

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission of the publisher.

iii

TABLE OF CONTENTS Page Message from the Vice Chancellor xv

Message from the Chairperson, Organizing Committee xvii

Organizing Committee xix

Panel of Co-Editors xxi

Guest Lecture xxiii

Part I : Agricultural, Biological and Medical Sciences SECTION 1: Faculty of Agriculture Genomic Variations of Colletotrichum musae Morphotypes Infecting Banana Varieties of Sri Lanka

1

N.F. Nazriya, D.M. De Costa and A.S. Azhaar

Use of Tn5 Transposon Mutagenesis to Screen Burkholderia spinosa Mutants Deficient in Antagonism against Colletotrichum musae

3

M.A.D. Wijerathne and D.M. De Costa

Development of Fancy Meat Loaves Using Natural Colorants 6 H.A.A. Dilrukshi, N. Lalantha, J.K. Vidanarachchi and H.W. Cyril

Effect of Curry Leaf (Murraya koenigii) in Beef Sausage on Blood Cholesterol Level of Mice

9

N.S.P. Malmuthuge, J.K. Vidanarachchi, S.M.C. Himali, R. Sivakanesan and H.W. Cyril

Molecular Characterisation of Lactobacilli Isolated from Digesta of Broilers Fed Prebiotic Plant Extracts

12

J.K. Vidanarachchi, L.L. Mikkelsen, P.A. Iji and M. Choct

Occurrence of Agamospermy in Artocarpus heterophyllus Lam. (Jak Fruit) 15 D.K.N.G. Pushpakumara

Gibberellin Repsonse of Phytochrome B Deficient Mutants of Lotus japonicus 18 L.D.B. Suriyagoda, S. Arima and A. Suzuki

Determinants of Potato Farmers’ Choices in Adopting Soil Conservation Practices in Nuwara Eliya District

20

D.G.V.L. Bandara and S. Thiruchelvam

Changes in Rice Consumption with Increasing Income 22 L.H.P. Gunaratne and D. Wickramaarachchi

Factors Influencing the Student Decision Making in Relation to University Admission

24

S.D.S Hemachandra and K.A.S.S. Kodithuwakku

iv

Organizational Design Features and Its Influence on Purchasing Performance: The Case of Garment Manufacturing Firms

27

D.N. Tirimanne and A. Ariyawardana

Regional Trade Integration Options for South Asia: A Welfare Analysis 29 J. Weerahewa

A Seismic Wave Detector with a Digital Display 31 P.M.K. Alahakoon

Contribution of Flavour Ingredients to Sensory Properties and Total Antioxidant Activity of Black Tea

33

S.P. Nissanka, U.K.S. Rodrigo, D.C.K. Illeperuma and A. Chandrasekara Effective Teaching Strategies for Teaching Science in Lower Secondary Classes: A Study from the Central Province

35

J.A.J. Hanee and D.C. Bandara

The Effect of Student-Centered Learning and Criterion-Based Assessment on Student Performance: A Study in Kandy and Matale Districts

37

Y.M.C.D. Yaparatna and D.C. Bandara

Socio–Economic and Institutional Factors affecting Community Participation in Conservation of the Knuckles Forest Range

39

A.K.C.J. Amarasekara, H.V.A. Wickramasuriya and H.M.S.K. Hennayake

Customer Resistance for Innovative Products: A Case Study on an Adhesive Tape 42 M. Senavirathne and S. De Silva

An Assessment of Special Programme for Food Security Project Interventions as Perceived by Farmers of Havandana

44

A.R.A.S. Wijesinghe and C. Sivayoganathan

SECTION 2: Faculty of Science and Postgraduate Institute of Science

Biological Sciences

A Preliminary Study on the Assessment of Limnological Changes of Kalu Ganga in the Knuckles Region using Biological Indicators

47

M.H. Perera and S.K. Yatigammana

Microbiological Quality of Bottled Water in Sri Lanka: A Preliminary Survey 49 C.L. Abayasekara, W.H.M.A.T. Herath, N.K.B. Adikaram, R. Chandrajith, S.C. Illapperuma, A.D. Sirisena and S.G. Rajapura

Effect of Caffeine and Epigallocatechin Gallate (Egcg) on Sporulation, Spore Germination and Mycelial Growth of Monacrosporium ambrosium, Ectosymbiote of the Shot-Hole Borer Beetle of Tea

51

N.B. Jayaratna, D.N. Karunaratne and N.S. Kumar

Thermally Stable Deoxyribonucleases from Nepenthes distillatoria (Bandura) 53 D. Chin, S. Rajapakse and S.B.P. Athauda

v

Antibiotic Activity of Tephrosia purpurea (Fabaceae) and Mimusops elengi (Sapotaceae) against Some Clinical Bacterial Isolates

55

B.N.L.D. Rangama, C.L. Abayasekara and G.J. Panagoda

Screening of Antioxidant Activity of Some Endemic Annonaceae Plant Extracts 57 S. Puvanendran, A. Wickramasinghe, D.N. Karunaratne, D.S.A. Wijesundara and V. Karunaratne

Anzia (Lichenized Ascomycetes, Parmeliaceae) A New Record from the Horton Plains National Park, Sri Lanka

60

R.G.U. Jayalal, P. Wolseley, L.G. Pathberiya, D.S.A. Wijesundara and V. Karunaratne

Does Mosquito Larvicide, Temephos Affect the Health of Local Amphibian Populations?

62

H.K.S.P. Harischandra, R.S. Rajakaruna and S.H.P.P. Karunaratne

Species Composition of the Family Chironomidae and their Relationship to Limnological Variables in Kandy Lake

65

L. Warusawithana and S.K. Yatigammana

Resource Partitioning and Competitive Interactions of a Tadpole Community in a Pond Complex in Gannoruwa Hills, Sri Lanka

67

K.D.B. Ukuwela and K.B. Ranawna

Phenetic Relationships of Wild and Cultivated Accessions of Cinnamon in Sri Lanka 70 M.M.K.G. Saumyasiri, D.M.D.Yakandawala, K.G.G. Wijesinghe and P. Samaraweera

Biosensor Approach for Monitoring Polyphenol Oxidase (PPO) Activity of Selected Local Fruits with Blanching Time (Steam Blanching)

72

A.N. Navaratne, D. Gunawardena, L. Kadawathaarachi and C. Ileperuma

Appearance and Recruitment of Trigona iridipennis Nests in a Selected Area in Peradeniya University Park

74

W.M.K.K. Karunaratne and J.P. Edirisinghe

Diversity of Wasps at Meewathura Agriculture Farm 77 S.R. Munasinghe and J.P. Edirisinghe

Identification and Prevalence of Eimeria Spp. causing Coccidiosis in Goats in Selected Sites from Kandy and Nuwara Eliya Districts

80

N.W.R.V.N. Bandara, R.S. Rajakaruna and R.P.V.J. Rajapakse

Antibacterial Activity of Oxacillin against Methicillin Resistant Staphylococcus aureus (MRSA) Pre-Incubated with Tea Catechins

82

W.W. Kumbukgolla, V. Thevanesam, N.S. Kumar and B.M.R. Bandara

Diversity of Dung Beetles in Dung of Cattle and Buffalo 84 M.H.V. Nawodinee and J.P. Edirisinghe

Ecto and Endo Parasites of Rodents from Two Selected Sites in Kandy District 86 K. Sumangali, R.S. Rajakaruna and R.P.V.J. Rajapakse

vi

Screening for Antibiotic Activity of Tea Catechins Against Pseudomonas aeruginosa and Enterococci

89

A.A.K. Karunathilake, W.W. Kumbukgolla, E.W.M.A. Ekanayake, V. Thevanesam, N.S. Kumar and B.M.R. Bandara

Chemotaxanomic Significance of the Fruit Constituents of Artocarpus altilis 92 N.R. Amarasinghe and U.L.B. Jayasinghe

Antifungal, Antioxidant and Cytotoxic Activity of Acronychia pedunculata and Adenanthera pavonina

94

S.K. Rodrigo, U.L.B. Jayasinghe and B.M.R. Bandara

Phytotoxic Constituents from the Fruit Juice of Averrhoa carambola 96 D.C. Gunawardena and U.L.B. Jayasinghe

Potential of Some Selected Larvivorous Fish Species in Aedes Mosquito Control 98 D.H. Ekanayake, T.C. Weeraratne, W.A.P.P. De Silva and S.H.P.P. Karunaratne

Chemistry and Mosquito Larvicidal Activity of Gnidia glauca 101 B.W.R.C. Amarajeewa, A.P. Mudalige and V. Kumar

Antioxidant Phenolic Constituents from the Fruits of Careya arborea 103 R.A.Y.K. Ariyaratna, N.R. Amarasinghe, D.C. Gunawardena and U.L.B. Jayasinghe

Histopathological Changes Induced by Venom of Bungarus ceylonicus on Laboratory Mice

105

D.P. Nanayakkara, P.G.L. Gunathilake, R.M.P. Ratnayake and J.G.S. Ranasinghe

Comparison of Antifungal, Phytotoxicity and Cytotoxicity of Seeds of Dolichos biflorus with some Edible Seeds

107

D.S. Jayaweera and U.L.B. Jayasinghe

Section 3: Faculty of Dental Sciences Emotional Effects of Wearing Complete Dentures 109 T. Anandamoorthy

Preliminary Study on Deregulation of cyclin D1 Protein Expression in Oral Squamous Cell Carcinomas with Reference to Different Histopahological Grades of Tumors

111

C. Abeysuriya, U.B. Dissanayake, A.K. Suraweera, S.A. Rajaratne and E.A.P. Amarathunge

Prognostic Significance of the Over Expression of Type I Growth Factor Receptor Family Proteins on the Survival of Patients with Oral Squamous Cell Carcinomas

113

U.B. Dissanayake

Matrix Metalloproteinase-9 (MMP-9) and Tissue Inhibitor of Metalloproteinase –2 (TIMP-2) Expression in Oral Verrucous and Squamous Cell Carcinoma

116

P.R Jayasooriya, A.K. Suraweera and N. Bandoh

Filling of Simulated Lateral Canals with Different Obturation Techniques 118 W.M.G.I.K. Wimaladharma, R.W. Pallegama, K.A. Wettasinghe and K.M. Wijerathne

vii

Changes in Periodontal Tissues and Gingival Crevicular Fluid with Friction and Non-friction Methods of Orthodontic Treatment

120

N.C. Wellappuli, J.K.C. Amarasena, A. Chandrasekera, N. Amarasena, K.A. Kalyanaratne and S.M.P.M. Ruwanpura

Development of an Antenatal Growth Chart using Maternal BMI in the Second Half of Pregnancy for Sri-Lankan Mothers

122

S.B.A. Dissanayake, U.B. Dissanayake and W.I Amarasinghe

IL-1α, IL-1ra are Differentially Induced by Candida in Experimental Human Oral Candidiasis

124

J.A.M.S. Jayatilake, L.P. Samaranayake and L.J. Jin

Influence of Personality Traits on the Attitudes Towards the Teaching Program and the Academic Performance of Dental Undergraduates

126

R.W. Pallegama, S. Ariyasinghe and H.A.E.D. Perera

SECTION 4: Faculty of Medicine The Prevalence of Known Risk Factors for Road Traffic Accidents (RTA) in Kandy Police Administrative Area

129

I.L. Wickramanayake, G.G.A. Gunasena, H.B.P.W. Wickramanayake and C.D.A. Goonasekera

Assessment of Toxicity of Bungarus ceylonicus (Ceylon Krait) Venom: Determination of Median Lethal Dose (LD50)

131

D.P. Nanayakkara, R.M.P. Ratnayake, R. Sivakanesan and S. Ranasinghe

Screening for Congenital Hypothyroidism in Government Hospitals in Sri Lanka 133 D. Nanayakkara, A. Wijekoon, N. Jiffry, R. Mudiyanse, J. Nilam, K. Perera, S. Herath and K. Solanki

Effectiveness of Laboratory Training of Undergraduates in Surgical Knot Tying and Skin Suturing Skills

135

M.D. Lamawansa and A.P. Perera

HHV-6A-Induced Phenotypic and Functional Alterations of Dendritic Cells 137 S.B. Adikari, M. Svensson and A. Fogdell-Hann

The Effect of Training on Some Physiological Parameters Related to Physical Fitness in a Population of Sri Lankan School Boys

139

K.C. Ratnatunga, K.I. Karunaratne, B.K. Dassanayake, I. Silva, A.A.J. Rajaratne and A.S.P. Mallawarachchi

Vital Functions During and Outcome Following Filtration Based Continuous Plasma Exchange in Guillain Barre Syndrome

141

S.P. Mudalige, Y.A.A. Jayasena, , G.S.M. Manchanayake, P.K.A.P. Kanankearachchi, P.V.R. Kumarasiri, H.L.P.S. Dharmapala, S.P.Ekanayaka and C.D.A. Goonasekara

Knowledge on Basic Trauma Care Among the Final Year Medical Students Gained from Clinical Work

144

M.D. Lamawansa and R.N.R. Arachchi

viii

The Effect of Occupational Exposure to Paddy Husk Dust on the Respiratory Health of Paddy Mill Workers in Sri Lanka

146

B.K. Dassanayake, K.C. Ratnatunga, K.I. Karunaratne, D. Nandadeva, S.D.I. Nanayakkara and A.A.J. Rajaratne

Factors Influencing Time of Death in Hospital 148 S.P. Mudalige, W.A.S.S.K Wijesuriya, C.R. Wanniarachchi, H.L.P.S.Dharmapala, B.M.P.K.D. Basnayake, S.D. Dharmaratne and C.D.A. Goonasekera

Laboratory Diagnosis of Trichomonas vaginalis Infection in Patients Attending the STD/Aids Programme Clinic in Kandy

151

D.R. Iddawela, G. Pathirana, N.L.S. Wijesundera and M. De S. Wijesundera

SECTION 5: Faculty of Veterinary Medicine and Animal Science Correction of an Acquired Oesophageal Stricture in a Dog: A Case Report 153 A.A.A.W.K. Amarasinghe, D.D.S. Wijetunge, M.N. Kularathne and D.D.N. De Silva

Brain Scoop: A Simple Post-Mortem Instrument to Collect Brain Samples for Diagnosis of Rabies

155

G.S.P. de S. Gunawardena

A Comparison of Clove Oil and Lidocain as Short-term Anaesthetics in Black Ruby Barb (Puntius nigrofaciatus)

157

S.K.N. Priyangika, S.R.D. Fernandopulle, B.G.S.J. Abeyrathne, M.D. Munasinghe and H.B.S. Ariyaratne

Poultry Offal Meal as a Substitute for Fish Meal in Feeding Tilapia Cultured in Cages

160

A.P. Jayasooriya, B. Samarasinghe, S.P. Gunaratne, E.R.R. Wimalasinghe, N.K. Weerasundera, N. Kudagama and G.S.P. de S. Gunawardena

The Effect of Different Doses of Cobra Venom on Mice as a Model for Investigation of the Tissue Damage

162

S. Halpage, K.B.J. Kumara, D.P. Nanayakkara, A. Dangolla and J.G.S. Ranasinghe

Identification of Androgen Induced Pigments in Guppies (Poecilia reticulata) 164 R.S. Devasurendra, A. Wanigasekera, A. Arulkanthan and A.P. Jayasooriya

Occurrence of Temperature Sensitive Haemagglutinin (TSH), Increase Serum Survival (ISS) and Col V Plasmid (CVA C) Genes in Chicken E. Coli in Relation to Serum Resistance

166

D.R.A. Dissanayake, T.G. Wijewardana, G.A. Gunawardena and I.R. Poxton

Immunohistochemical Detection of Rabies Virus Antigen in the Brainstem and Spinal Cord of Rabid Dogs in Sri Lanka

168

G.S.P. de S. Gunawardena and W.F. Blakemore

A Preliminary Study on the Proteins found in the Epididymal Fluid of the Goat 170 J.K.A. Deepanee, R. Subramanium, V.K. Gunawardana, H.B.S. Ariyaratne, R.P.V.J. Rajapakse, N.A.N.D. Perera, D.C.A. Gunawardana and D.M.S. Munasinghe

ix

Seasonal Variation in the Occurrence of Acanthamoebae Species in the Eyes of a Group of Captive Elephants in Sri Lanka

172

P.N.K. Wijesekara, K.A.P.A. Bandara, A. Dangolla, J.S. Edirisinghe and I.D. Silva

Analysis of Urine Obtained from Captive Elephants in Sri Lanka 174 A.T.M. Gamage, K.A.P.A. Bandara, A.A.J. Rajarathne and A. Dangolla

Intoxication of a Police Working Dog following Ingestion of Explosives (Tnt, C-4 and Plastic Explosives)

175

S.J. Wijesinghe, W.P.T.T. Weerasinghe and I.D. Silva

Successful Correction of Mandibular Fractures with Dynamic Compression Plates in a Pregnant Bitch

177

M.N. Kularatna, M.G.C.M. Jayasinghe, W.R.B. Kumara, A.A.A.W.K. Amarasinghe, S.J. Wijesinghe, D.D.N. De Silva, I.D. Silva, I.S. Hewapathirana and H.S. Ranasinghe

Part II : Engineering, Physical Sciences, Humanities and Social Sciences

SECTION 6: Faculty of Engineering Computation of Bed Shear Stress in Unsteady Open Channel Flows 179 K.P.P. Pathirana, P.C. Ranasinghe and U.R. Ratnayake

Experimental Investigation of Rainfall Induced Soil Erosion 181 H.M.R.M. Aberathna, W.T.D. Nandasiri, S.N.K. Sandamalika and K.P.P. Pathirana

A Non-Dimensional Approach to Predict Bed Load Transport in Unsteady Flow 183 P.C. Ranasinghe, K.P.P. Pathirana and U.R. Ratnayake

Entrance Zone Effect on the Sediment Trapping Efficiency in Desilting Tanks of Run-of- River Type Mini-Hydropower Plants

186

U. Rathnayake, M.R.T.S. Harishchandra and S.B. Weerakoon

Flow Modeling of the Maha Oya at Peradeniya 188 D.M.A.G.B. Dissanayaka, U.J. Dissanayaka, D.A. Sachindra and S.B. Weerakoon

Issues Arising from Water Encroachments along Hurulu Wewa Feeder Canal 190 A. Abeynayaka, D.R.I.B. Werellagama and G.N. Paranavitana

Study of Cassava Starch Hydrolysis by α-Amylase and an Airborne Mould Culture 193 W.A.L.D. Wickramasinghe, S. Sotheeswaran, U.S.K. Weliwegamage, S. Rajapakse and C.S. Kalpage

Cross-Sectional Assessment of Chlorpyrifos in a Small Stream Running Through a Densely Cultivated Area in Kandy District

196

A.M.W. Menike, C.S. Kalpage and. R. Shanthini

x

Design of a Paddy Husk Charcoal Adsorption Unit for the Treatment of Parboiled Rice Processing Wastewater

199

S.M.W.T.P.K. Ariyarathna, C.S. Kalpage and R. Shanthini

Effect of Process Parameters on the Quality of Instant Tea 202 I.R. Samarathunga and D.G.G.P. Karunaratne

Use of Light Absorption in the Fabrication of a Device for Measuring Ambient Black Carbon Concentration

205

N.M.N.V. Bandara, P.S. Palugaswawa and M.A. Elangasinghe

Application of Electro-Coagulation for the Treatment of Wastewater from Vehicle Service Stations

208

I.R. Samarathunga and D.G.G.P. Karunaratne

Strength and Ductility Evaluation of Rigid-Frames Using Finite Element Analysis 211 K. A. S. Susantha and T. Aoki

Initiation of Thermal Cracks in a Weir 214 M.M.G.V. Shyamalee, C.K. Pathirana, H. Abeyruwan and K.R.B. Herath

Application of Multiaxial Sequential Law to Estimate Secondary Stress Based-Fatigue Life of Riveted Connections

217

P.B.R. Dissanayake and S.A.S.C. Siriwardane

Reliability Based Resource Allocation in Bridge Maintenance 219 P.B.R. Dissanayake and P.A.K. Karunananda

Seismic Review Sheet for Evaluation of Earthquake Risk of Bridges 221 H.M.K.G.G.H.B. Herath, L.G.A. Liyanage, M.G.B.S. Manangoda and P.B.R. Dissanayake

Equivalent Electric Network Model for Ionic Polymer Metal Composite Dynamics 224 B.G.L.T. Samaranayake and A.M.U.S.K. Alahakoon

Implementation of an Electronic Tuner in J2ME using Fast Fourier Transform 227 I. Herath and R.G. Ragel

Full Instruction Encoding for Heterogeneous Multi Pipeline Application Specific Instruction-Set Processors

230

S. Radhakrishnan and R.G. Ragel

An Algorithm for Automatic Playlist Generation in Radio Stations 233 I.M.K. Kahanda and U.G. Kanewela

User Dependant Speech Based Lip Synchronization 236 S.M.I. Wickrama and J.V. Wijayakulasuooriya

Design of an All-In-One Billing Meter for Three Wheelers in Sri Lanka 238 B.G.L.T. Samaranayake

xi

Memory Efficient Algorithm and Closed Form Formulas for Computing Odd Magic Squares of Higher Order

241

P.C. Perera

An Efficient Algorithm to Compute the Square of a Binary Number 244 M.G. Arlis and P.C. Perera

Modified Stepping Stone Algorithm for Solving Large-Scale Balanced Transportation Problems

246

B.M.R.K. Basnayake and P.C. Perera

Controller Design and Implementation for Cost Effective Mobile Robots 249 I.B. Wijayasinghe and B.G.L.T. Samaranayake

An Efficient Algorithm to Compute the Reciprocal of a Binary Number 252 P.C. Perera

Error Correction Model for Predicting the Carbon Dioxide Emissions of a Coal-based High-income Economy

255

R. Shanthini and K. Perera

Experimental Investigation of Condensation Heat Transfer Coefficient of Refrigerants during in Tube Condensation

258

L. Rajapaksha and Y.M.C.E.K. Abeykoon

Analysis of the Effect of Excessive Temperature and Humidity in a Production Environment

261

L.U. Bakmeedeniya

Limitation on Connecting Mini Hydro Power Plants to the Sri Lankan Power System Network: A Case Study at Balangoda Grid Substation

263

A.I. Weerasekera, A. Arulampalam and J.B. Ekanayake

Microgrid Operations: Case Study at Nilambe Mini Hydro Grid 266 D.N. Navaratne, J.B. Ekanayake and A. Arulampalam

Power Factor Correction and Harmonics Effect to an Industrial Load 269 S.K. Abeygunawardane, K.I.R. Prasanna, A. Arulampalam and J.B. Ekanayake

Modelling Sri Lankan Power System to Study the Effect on Dynamic Stability with Large Scale Wind Power Integration

272

R.H.B. Ekanayake, A. Arulampalam and J.B. Ekanayake

SECTION 7: Faculty of Science and Postgraduate Institute of Science:

Physical Science

Structural Studies of Plant Pigments Used in Dye Sensitized Solar Cells 275 F.M. Hussain, V. Sivakumar and K. Tennakone

Layers – An Abstract Extension of Fields for Higher Dimensions 278 H.M. Nasir and M.S.M. Waasim

xii

Deriving Shrunken Estimators for the Variance in One-Parameter Natural Exponential Families

281

A. Laheetharan and P. Wijekoon

Major and Trace Element Composition of Bottom Sediments of the Malagane Tank: Relationship with Sources

284

K. Mahatantila, R. Chandrajith and H.A.H. Jayasena

An Econometric Model for Hyper Inflation 286 H.G.K. Dineshanrathna and U.N.B. Dissanayake

Integer Solutions of Non - Linear Diophantine Equations Using Continued Fractions 288 A.G.K.N. Alupotha and A.A.I. Perera

Geochemical Characterization of Surface Water and Groundwater in Some Areas of Northcentral and Northwestern Sri Lanka

290

S.M. Young, A. Pitawala and J. Gunatilake

High-Speed Counter-Current Chromatography for the Isolation of Proanthocyanidins from Tea Flush

292

W.M.A.M.B. Wijekoon, N.S. Kumar and P.A.N. Punyasiri

Combined Catalytic Activity of Cation-Exchanged Montmorillonite and Camphorsulfonic Acid in the Preparation of Cumene from Benzene and 2-Propanol

294

S. Wijeratne, R.M.G. Rajapakse, D.T.B. Tennakoon, H.M.N. Bandara and B.M.R. Bandara

Adsorption of Chromium(III) on Fired Brick Particles 296 N. Priyantha and C. Seneviratne

Chemical Reactivity of Mica, K-Feldspar and Apatite in Organic Acids and Water 298 T.H.N.G. Amaraweera, A. Pitawala and G.W.A.R. Fernando

Deterioration of Groundwater Quality in Tsunami Affected Coastal Aquifers in Sri Lanka and Complexities in Natural Recovery

301

H.A. Dharmagunawardana, A. Welagedara, A. Pitawala and M.N.A. Mubarak

Synthesis of a Novel Copper (II) Complex Capable of Trapping Hazardous Cations Present in Water

304

A.M.K.S.P. Adhikari and M.Y. Udugala-Ganehenege

Learning Chemistry Using Analogies 307 M.M. Jamila and S. Karunaratne

Determining the Optimal Order Quantity Using a Simulation Model 309 T.H.K.R. De Silva and W.B. Daundasekara

Synthesis and Characterization of Layered Double Hydroxide (LDH)/Sugar Nanocomposites for Pharmaceutical Applications

312

S. Indrasekara, V. Karunaratne and N. Kottegoda

Computational Efficiency of Weakly Orthogonal Spherical Harmonics in Cubed Sphere

315

M.A.A.M. Faham, H.M. Nasir and T. Kaneshalingam

xiii

Preliminary Investigation of the Liquid Crystal Behaviour of β-sitosteryl-β-D-glucopyranoside

318

G.L.A.D. Liyanage, A.D.L.C. Perera and D.N. Karunaratne

Equilibrium Studies on Cadmium (II) Interactions with Aspirin and Vitamin C in Aqueous Medium

320

H.H.M.C.U. Herath and C.V. Hettiarachchi

Attempted Synthesis of a Glucofuranose Derived Carbohydrate Liquid Crystal 322 L.S. Widanapathirana, A.D.L.C. Perera and D.N. Karunaratne

SECTION 8: Faculty of Arts Geography in Practice: ‘Conceptualizing Space’ in Print Media in Sri Lanka 325 S.K. Hennayake and N. Hennayake

Preparation of a Zoning Plan for the Madu Ganga Special Management Area 327 E. Vidanapathirana, P. Wickramagamage and S.P. Nishshanka

Virtual Peradeniya :A GIS System for the University of Peradeniya 329 R. Alagan, D. Weragodetenne, U. Jeyaraman and C. Premaratne

Farmers` Perceptions Towards Climate Change and Farm Management Practices 332 K.W.G.R. Nianthi

Changing Landscape of Kandy 334 A.S.M. Nawfhal

Vessagiriya: Epigraphy and Palaeography 336 A.M.P. Senanayake

Characterization of Soils at the Vessagiriya Archaeological Site in Relation to Past Settlement Sites

337

A.M.C.P.K. Attanayake, R.B. Mapa and S. Seneviratne

Functional Uses of Stone Outcrops at Anuradhapura Vessagiriya: An Environmental Archaeological Study

339

T. Wagalawatte

The Ecological Values Reflected in the Buddhist Vinaya (Discipline) 340 M. Gnanananda

Is ‚HA a Cluster in Pali Language ? 341 M. Wijitadhamma

The Frankfurt School of Social Research and Critical Theory, with Special Reference to Max Horkheimer

342

M. Rajaratnam

Children’s Posttraumatic Emotional Distress and Coping After a Natural Disaster: The 2004 Tsunami

344

G.R.K. Dissanayake and V. Ganepola

xiv

Philosophical and Systematic Analysis of Diotima's Definition of Love and Its Relation to Plato's Theory of Forms in the Symposium

346

A. Samaratunge

Euripides’ Alkestis “A Drama of a Devoted Wife?” Translation from the Original Greek into Sinhala with an Introduction and Commentary

348

C.S.M. Wickramasinghe

Issues in Translating 'Sexuality' into Sinhala: Inadequacy of the Terms Used in the Sinhala Translation of Lady Chatterley's Lover By D.H. Lawrence

350

D.M. Kumarasinghe

‘Observer’s Paradox’ in Linguistic Research 352 A. Velmurugu

Economic Growth and Human Capital Investment in Sri Lanka 353 K.M.G.A. Kasturi and A.S.P. Abhayaratne

Foreign Direct Investment and Economic Growth in Sri Lanka: A Causality Approach

355

N. Balamurali

The Causes of Domestic Violence and Its Impact on Rural Women Victims 357 J.A.P.S. Perera

External Intervention and Conflict Outcome: Analyzing the Effects of Intervention Strategies in Sri Lanka

359

M.M. Ihjas

Classroom Realities 361 S.K. Embakke

A Study on Gender Differences in Food Habits and Sport Performance among Secondary School Boys and Girls in Sri Lanka

363

W. Senevirathne and P. Sethunge

A Study of Western Musical Techniques Used in Sinhala Light Songs During the 20th Century

365

M. Alawathukotuwa

The Original Concept of Sound Material in Chinese Music Sheng) and Yin

367

L. Seneheweera

Masculinity in Kandyan Dance 368 S. Mantillake

Identification of Mule (Equus Hemionus) as Aśvataraya in Ancient Sri Lanka by Unearthed Bones and Literature

370

R.M.M. Chandraratne

Author Index 373

xv

Message from the Vice Chancellor Peradeniya University Research Sessions 2007 Peradeniya University Research Sessions (PURSE) is an annually held event and this year it is scheduled to be held on the 30th November, 2007. This has become an important academic event of the University calendar. Generation of new knowledge through research into important problem areas by both university teachers and students is part of the higher education process. In order to facilitate the teachers and students to take up this challenge, the University of Peradeniya conducts over two hundred internationally and locally funded research projects, annually. The PURSE provides an ideal forum for staff and student researchers to present their research findings to a wider audience enabling their work to be reviewed evaluated by a learned panel of judges. The experience gained during PURSE generates confidence amongst the researchers and help them to perform better in their future endeavours. Therefore, continuation of PURSE in a sustainable manner is of utmost importance to the University of Peradeniya. I wish to express my deepest gratitude on behalf of the University of Peradeniya for Honourable Minister Dr. Sarath Amunugama for accepting our invitation to be the chief guest of the PURSE, 2007. Organizing the PURSE is not an easy task and the members of the Organizing Committee have taken up the responsibilities assigned to them. The request of papers from all faculties and the review and publication procedures take a substantial time of all members, referees and editors. This year’s Chairperson, Dr. S.D. Dewasurendra, took up the challenge of coordinating the activities of the research sessions with dedication to complete the task assigned to him. I take this opportunity to compliment him on this occasion. I am also very grateful to the members of the organizing committee comprising of academic and non- academic staff and students of all faculties for their invaluable support and assistance in organizing the annual research Sessions 2007. I take this opportunity to wish all the paper presenters and participants a rewarding day. Prof. Harischandra Abeygunawardena VICE-CHANCELLOR

xvii

Message from the Chairperson, Organizing Committee Peradeniya University Research Sessions 2007 Peradeniya University Annual Research Sessions are being held for the 12th time when the university completes its 65th year. Being the most comprehensive university with the oldest tradition in the country, these sessions must certainly mean something special. The line-up of academics and their credentials are impressive by regional standards and, one would expect to find a hive of research and development activity in the midst of an enlightened group as ours. Certainly such activity has to reflect amply on the research outputs as presented in its annual research sessions.

We have some 160 peer-reviewed papers being presented, covering most of the disciplines in the eight academic faculties. However, we must not hesitate to confront the reality that a large proportion of what is being presented report work carried out in basic undergraduate laboratories/facilities.

Research is an inspirational activity which explores the limits of possibility, exercising the creative faculties to the limit. When economies operate at below subsistence levels, like in the case of ours, there are overwhelming needs of a very basic nature in every sphere of human activity. This coupled with the fact that there is a continuum of levels of development visible in different countries, which have suddenly come to our very door-step through hyper-quick communication media, open up almost limitless possibilities to those who seek some activity to keep occupied. Therein, the craftsman, very justifiably, finds a fertile activity field and the versatile student too, simple, real-life applications to sharpen newly acquired knowledge and skills. However, it is very unlikely that such activity would reach the threshold of breakthroughs that form the back-bone of any nation in the vanguard.

It is not possible to force creativity out of people, and all those who have the grasp of fundamentals and the tools to manipulate them cannot necessarily be expected to use such knowledge to generate inspirational levels of research activity. Most seem to content themselves in rejoicing exploits, worthy though, of the versatile student in his act of sharpening teeth. No wonder then, that we are where we are and we see the horizons that we see. Let us not fool ourselves. How many really come looking for advanced learning to our shores? How many times has the country been able to take advantage of its own research findings to create a difference to its own lot?

Then how, one would ask, does it happen where it really does? Arguably, when those who can and are willing get what they need to exercise their inspired activity. And, what exactly is this that they need? They need their domain, the domain that contains the facilities for their activity and the freedom to explore and create. And how would they get this domain? In nations at advanced degrees of development in the respective spheres, the domains are being created, either through the needs of private enterprise or through the planned research & development programmes of the state. The necessary funds come through regeneration. In a country where resources are scarce in both these forms, the only possibility remains the tapping of resources of outside domains: basically, bringing in work that can be carried out locally and delivered to the overseas domain, securing precious funds for local capacity building. This could continue till local capacity builds up to sufficient levels. Otherwise it would be inevitable to stay within the vicious circle of ignorant bliss.

The task is not easy by any means, because gaining visibility in overseas domains and developing the requisite level of confidence would be an immense barrier to break through. However, there are

xviii

things that we could do to improve our chances in this venture. To start with, let us not despise the enterprising academic for building his own domain. Let us facilitate the networking of such enterprising academics into functional research groups. Let us identify the difference between research and resulting creation of new knowledge and the activities of teaching and forming young graduates and undergraduate project work which is meant to sharpen their skills in the use of newly acquired knowledge. Let us understand clearly that at any given moment of time, there are these two focuses and that correspondingly there are two distinct groups of adepts. Let us also understand that the former group could potentially perform better than the latter in its own task. Let us not permit the majority power of mediocrity stifle the efforts of the researcher to kindle the little flame of inspiration that could light up the lot of the majority too.

Having said that, we must place on record our deep appreciation of all those who toiled hard to make PURSE-2007 another significant landmark in our pursuit of excellence. The researchers presenting papers, the editor and the editorial committee are to be commended first. The unfailing support and guidance of the Vice Chancellor have been a source of strength. The commitment shown by the different committees and their chairpersons, personnel from the Council & Academic Unit and University administration in general once again demonstrated the hidden strengths we can draw upon. We also note with gratitude, the donations by the National Science Foundation and the Postgraduate Institute of Science towards the printing of conference proceedings. We are grateful to Honourable Minister Dr. Sarath Amunugama for accepting our invitation to be the Chief Guest and our Chancellor, Dr. Premadasa Udagama for accepting to grace the occasion as Guest of Honour. We record our gratitude to Professor G. P. Karunaratne for accepting our invitation to deliver the Guest Lecture. Dr. Shirley Devapriya Dewasurendra Chairperson of the Organising Committee PURSE 2007

xix

PERADENIYA UNIVERSITY RESEARCH SESSIONS PURSE – 2007

ORGANIZING COMMITTEE

Chairperson of the Organizing Committee Dr. S.D. Dewasurendra

Director, Research & International Affairs Prof. R.O. Thattil Director, Postgraduate Institute of Science Prof. M.A.K.I. Dissanayake Director, Postgraduate Institute of Agriculture Prof. A.L.T. Perera

Chairpersons of the Faculty Research Committees

Faculty of Agriculture Prof. C. Sivayoganathan

Faculty of Allied Health Sciences Prof. V. Thevanesam

Faculty of Arts Dr. D.K. Jayaratne

Faculty of Dental Sciences Dr. M.A.M. Sitheeque

Faculty of Engineering Dr. S.D. Dewasurendra

Faculty of Medicine Prof. R. Sivakanesan

Faculty of Science Prof. A.D.L.C. Perera

Faculty of Veterinary Medicine and Animal Science Dr. H.B.S. Ariyaratne

Faculty Representatives

Faculty of Agriculture Dr. D.N. De Costa Mr. B.M.L.D.B. Suriyagoda Faculty of Allied Health Science Mrs. H.M.D.R. Herath Mrs. P. Saravanakumar Faculty of Arts Dr. K.M.G. Rekha Nianthi Ms. Careema Jayaweera Faculty of Dental Sciences Dr. J.K.C. Amarasena Dr. M. Attygalla Faculty of Engineering Dr. U.R. Ratnayake Dr. K.R.M.N. Ratnayake Faculty of Medicine Prof. M. Sabanayagam Prof. S. Rosairo Faculty of Science Dr. V.A. Seneviratne Dr. H.A. Dharmagunawardena Faculty of Veterinary Medicine and Animal Science Dr. A.W. Kalupahana Dr. L.J.P.A.P. Jayasoorira

xxi

PANEL OF CO-EDITORS

Faculty of Agriculture Prof. D.C.K. Ileperuma Dr. W.P.R.P. de Silva Faculty of Arts Prof. A. Parakrama Dr. D.N.B. Gunawardena Faculty of Dental Sciences Dr. H.D.N. Amarasena Dr. R.W. Pallegama Faculty of Engineering Dr. R.G. Ragel Dr. D.G.G.P. Karunaratne Faculty of Medicine Dr. K. Pethiyagoda Dr. W.I.T. Fernando Faculty of Science Prof. H.M.D.N. Priyantha Dr. K.U. Tennakoon Faculty of Veterinary Medicine and Animal Science Prof. T.G. Wijewardena Dr. A.R. Mohomed

xxiii

Guest Lecture

Is Research Needed?

G.P. Karunaratna

International Consultant to Southern Transport Development Project, Sri Lanka Adjunct Professor, National University of Singapore

In a research community such as a university, the answer to the above is generally clear. Many university professors undertake post-graduate training and research as part of their profession. But should this be limited only to the beginning of the career?

If the meaning of research is to ‘search’ for knowledge then there is always something different to look for. Should the ‘knowledge’ be limited to theory? Is the acquired knowledge useful only for the researcher who raised the level of knowledge? Should he be complacent that his knowledge is expanded? Will his results lead to knowledge being shared among the community? Should the shared knowledge lead to welfare of and to uplift the society? Taking a more humanistic approach it would be ideal to focus one's energy for searching and advancing knowledge for the benefit of all species, far and near.

Following the perception expressed above the research finding should advance the intangible knowledge and/or tangible applications stemming there from. The former eventually may lead to ‘tangible’ applications such as spiritual emancipation. The latter provides a seeding ground for development work in all spheres.

Much of the effort devoted for research is based on the human mind. Certainly sharper the mind better would be the analytical assessment and the grasping power of the work. Those who need equipment and associated material for research have to depend on funding which may not be available readily. Funding agencies are sought after by the researchers at this stage. These may constitute public or private organizations and institutions, based on the need for a solution (knowledge that is necessary) for a given problem. Private organizations thrive in the West as funding agencies through reasonable assessment of the potential commercialization of research finding.

Public organizations, such as government institutions, provide little to large-scale support in the West, whereas only a handful of governments in the East encourage research. Such applications on a large scale include US space program and defense. Private sector dominates in pharmaceutical, biological and electronic industries among thousands of different research areas. Thus it would not be easy to imagine how this world would be without the research conducted by all the humans since the inception of the world, be they ancestors or not. Therefore, whether the finding is stoneware in the prehistoric time or Edison’s electric bulb or nanotechnology or space structures, to take a minuscule of examples, research has yielded knowledge in a practical sense for the benefit of the mankind. Occasional use of such findings towards destruction is disheartening for many.

Choice of a viable topic is researcher’s option, and sometimes the funding agency that needs results for an unresolved issue. Funded research should produce achievable targets. They should preferably be completed within the stipulated time frame and budget. However it would be more enjoyable to witness the application of one’s research findings if the opportunity arises.

xxiv

At the time the speaker accepted an offer to become a professor at the University of Singapore funding for research was an attractive thought. No sooner he arrived with his young family he was requested to provide advisory services to the panel of engineers for the construction of the Changi International Airport in Singapore replacing the much congested smaller airport in the island of 525 km2. The natural sand available in the sea bed was dredged for reclaiming a 750 ha of new land upon which the new airport facilities were to be built. Sand was placed on 40 m deep marine clay in the sea bed which was to compress about 3 m under 10 m thick new land. Since it takes more than 30 years to accomplish this settlement if left untreated, it became obvious that the soft clay must be pretreated so as to preclude future settlement. The only available band drain to reduce time of treatment at that time was made with a plastic core and a paper filter. During installation it was observed that the paper filter tended to tear off in the air when gusty wind blew at 40 km/hour. The speaker was able to assemble a completely natural band drain composed of coconut coir and jute fibre that surpassed the tensile strength of all band drains.

Being a third world country, in mid seventies, Singapore University had to seek the services of a London Solicitor for patenting the product which became the first patent of the Singapore University. Subsequently the product was tested in the same marine clay with identical performance of the other band drain. The patent has expired after 20 years and stands to benefit the community of civil engineers. It has been used in Singapore, Malaysia, Japan and Sri Lanka on commercial projects for soft ground improvement.

Enjoyment and monetary return from such patented innovation are benefits of the research. When the patent expired the development becomes people’s inheritance. Benefits accrued by the community gives an additional enjoyment which is in the realm of sharing knowledge. Hence research is to advance knowledge in all fields, be they intellectual or practical. The community should be able to share the benefits as part of the research effort.

Part II

Engineering, Physical Sciences, Humanities and Social Sciences

FACULTY OF ENGINEERING

Proceedings of the Peradeniya University Research Sessions, Sri Lanka, Vol.12, Part II, 30thNovember 2007

179

Computation of Bed Shear Stress in Unsteady Open Channel Flows

K.P.P. Pathirana*, P.C. Ranasinghe and U.R. Ratnayake

Department of Civil Engineering, Faculty of Engineering, University of Peradeniya Introduction An accurate computation of bed shear stress is important in estimating sediment transport rates in open channels, rivers and streams. The computation of bed shear stress in steady, uniform flow has been extensively investigated by many researchers. Very few studies have been reported in the past investigating the bed shear stress in unsteady flows and most of the studies do not provide conclusive results. In general, the flow in rivers and streams is unsteady and non-uniform. The computation of bed shear stress in this type of flows is still based on the formulations that are developed for steady, uniform flow conditions. The present study is aimed at investigating the estimation of bed shear stress in unsteady open channel flow over rough bed using extensive laboratory experiments (Tu and Graf, 1993).

Methodology Using the partial differential equations developed by de Saint Venant for unsteady flows, shear velocity of unsteady flow is written as (Henderson, 1996);

⎥⎦

⎤⎢⎣

⎡∂

∂−

∂∂

−∂∂

−=t

Ugx

UgU

xySgyu un

1*

(1)

where, U is the depth-averaged velocity, y is the water depth and S is the channel bottom slope, The unsteady flow considered in the proposed study is generated by passing hydrographs in an open channel and hence, the derivatives x/y ∂∂ and x/U ∂∂ in the above equation are changed to time derivatives t/y ∂∂ and t/U ∂∂ using the wave velocity concept and u* is presented as;

⎥⎦

⎤⎢⎣

⎡⎟⎠⎞

⎜⎝⎛ −

∂∂

−⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+

∂∂

=CU

tURS

ty

CRgu un 11

* (2)

Where, gyUC += and R is hydraulic radius.

When passing a hydrograph in the channel, it has been shown that the rate of change of water level is more significant than that of mean velocity and, as a result, the contribution of the

second term in Eq.(2) for estimating u* can be assumed to be very small. Therefore, shear velocity in unsteady flows can be expressed by the following simplified equation,

⎥⎦⎤

⎢⎣⎡

∂∂

+=tygR

CgRSu un

1*

(3)

Experimental set-up and procedure The experiments were carried out in a 10 m long, 0.4 m wide, 0.5 m deep rectangular, re-circulating, tilting flume. The size of natural river sand used for the experiments is between 2 mm and 8 mm. The fixed bed was prepared by gluing a single layer of sand on the channel bed with cement slurry. The base flow of a known quantity was first allowed to flow over the fixed bed. Using an additional pump in addition to those used in the re-circulating system and with preset valve opening and timing the pump running durations, six hydrographs were passed over the steady base flow. Each hydrograph was repeated several times to ensure repeatability. The experiments were repeated for four different channel slopes and four different base flow discharges, with six hydrographs each, leading to a total of 96 test runs. The water depths were measured continuously during the tests using pressure sensors and all observations were logged into a computer using an Analogue-Digital converter.

Results and discussion Unsteadiness of flows was quantified using a hydrograph parameter (HYDP), which is defined as;

( )2*

)(2

DTu

yyyHYDP

b

pbp −= (4)

Where, yb is the water depth in the base flow, yp is the water depth at peak, u*b is the shear velocity in the base flow and DT is the duration of hydrograph. The HYDP of test cases varied between 3.17×10-4 (most unsteady) and 1.52×10-5 (least unsteady). As a typical result


180

of the unsteady flow runs, the time variation of water depth and shear velocities during the passage of a hydrograph is shown in Figure 1. Figure 2 compares the u* values based on the

steady and unsteady formulae during the passage of a hydrograph with a HYDP of 3.17×10-4. The difference in shear velocities derived from the steady and unsteady flow equations seems to increase significantly for the rising and falling limbs of the hydrograph as illustrated in Figure 2. It clearly shows that the shear velocities in the rising limb are higher than that in the falling limb.

It can be seen from Figure 3 that the maximum difference in u* computed by the two methods is generally larger in the rising limb than that in the falling limb and that it always remains less

than 3% in the base flow. The maximum value of ( )suu **/Δ increases with HYDP indicating that the error can be as high as nearly as 30% and 20% in the rising and falling limbs, respectively when HYDP is high. The difference in shear velocities computed by steady and unsteady formulae was derived as,

11

11*

**

*

* −∂∂

⎥⎦⎤

⎢⎣⎡

++=⎟

⎟⎠

⎞⎜⎜⎝

⎛ −=

Δty

FrFr

USuuu

uu

s

sun

s (5)

Where, Fr is the Froude number and u*s is the shear velocity in steady uniform flow, which is given by .)/( 5.0

0* ρτ=stu

Conclusions The behaviour of bed shear stress in unsteady flow was studied using extensive laboratory experiments over a rough bed. The shear velocity in unsteady flow derived from de Saint Venant equations was compared with the steady state formula. The shear velocity is usually larger in accelerating flow than that in decelerating flow. The difference in shear velocities computed by the steady and unsteady flow equations was quantified and compared with the experimental results. A relationship between steady and unsteady shear velocities has been derived in terms of hydraulic parameters of the problem, which can be used to quantify the error in using steady state formula of u* for unsteady flows.

References Henderson, F.M. (1996) Flood waves in

prismatic channels, Journal of Hydraulic Engineering, ASCE, 89(4), 39–67.

Tu, H. and Graf, W.H. (1993) Friction in unsteady open-channel flow over gravel beds, Journal of Hydraulic Research, 31(1), 99–110.

0%

10%

20%

30%

40%

0.0E+00 5.0E-05 1.0E-04 1.5E-04 2.0E-04 2.5E-04 3.0E-04 3.5E-04

HYDP

max

( Δu*

/u*4

)

ris ing limb

falling limb

base flow

Figure 3. Variation of maximum ( )suu **/Δ

with HYDP in the rising and falling branches of the hydrographs

S4Q4 data - HYDP = 3.17E-04

3.0

3.5

4.0

4.5

5.0

5.5

6.0

3.0 4.0 5.0 6.0u*4 (steady)

u * (u

nste

ady)

Rising limbFalling limb

Figure 2. Comparison of shear velocities

computed by steady and unsteady state formula

HYDP= 1.25E-04

2.0

3.0

4.0

5.0

6.0

1 11 21 31 41 51 61 71 81 91 101Time (s)

y(c

m)

4.0

5.0

6.0

7.0

8.0

u * (c

m/s

)

yu*steady (u*s)u* unsteady

Figure 1. Variation of water depth and shear

velocity in an unsteady flow run


181

Experimental Investigation of Rainfall Induced Soil Erosion

H.M.R.M. Aberathna, W.T.D. Nandasiri, S.N.K. Sandamalika and K.P.P. Pathirana*

Department of Civil Engineering, Faculty of Engineering, University of Peradeniya Introduction It is widely recognized that rainfall induced soil erosion is a serious global problem with significant financial and environmental consequences. Soil erosion is particularly important in agricultural lands, where it results in a reduction of the cultivable soil depth and fertility. In addition, the problem of sedimentation on riverbeds and drainage networks, which reduces their capacity, increases flooding risk, blocks irrigation canals and shortens the design life of water reservoirs. Soil erosion is a two-phase process consisting of the detachment of individual soil particles from the soil mass and their transport by erosive agents such as running water and wind. Finding an analytical solution to soil erosion problems is impossible; therefore most studies are mainly based on laboratory experiments and the field investigations. The main objective of this research was to carry out an experimentally investigate the rainfall driven erosion process and to develop a functional relationship to quantify soil erosion rates.

Experimental set-up and procedure Based on preliminary tests carried out in the field to find out actual characteristics of natural rainfall, a laboratory-scale rainfall simulator

was designed and fabricated using perforated PVC pipes and a nozzle as shown in Figure 1. To generate raindrop distribution similar to

natural rain, a frame mounted with the perforated pipes and the nozzle was moved back and forth with a span of about 10 cm using a wiper motor. The height of the moving set-up above the ground level was determined after carrying out several preliminary tests. The drop size distribution was tested using a tray filled with flour, which was briefly exposed to a rain and covered it back within a fraction of a second. The number of drops with different diameters was then counted. The drop size distribution simulated by the rainfall simulator is compared with actual rain in Figure 2. A soil bed with dimensions 600 x 600 x 100 mm was used for the tests, which consists of 70 mm thick soil sample placed on a layer of 30 mm thick porous bed to remove infiltrated water. The experimental set-up is as shown in Figure 3. The soil erosion rates were measured for five different soil bed slopes, four different soil types and four different simulated rainfall intensities.

Results and discussion The soil erosion rate (q) depends on many parameters, such as rainfall intensity (I), mean diameter of raindrops ( rd ), mean diameter of soil particles ( sd ), dry density of soil (ρ), bed slope (S), acceleration of gravity (g), impact

velocity of rain drops (V), soil characteristics (K), support factor to represent any erosion

Figure 1. Two types of arrangements used to set-

up the rainfall simulator

Figure 2. Comparison of drop size distribution generated by the rain simulator with a typical rain


182

R2 = 0.7624

0

50

100

150

200

250

0 100 200 300 400q calculated

q ex

perim

enta

l

control measures (Po). The above parameters can be correlated by an equation of the form;

0),,,,,,,,,( 0 =ρ qPKPgSddIf sr … (1)

A few of the listed parameters, which were kept as constants during the experiments, can be excluded from the analyses. The raindrop velocity was not taken into account here as it is difficult to measure and control during the tests. The clay content (c) was taken as the soil characteristic in the experiments. Hence, the Eq. (1) simplifies to:;

0),,,,,,,( =ρ qcgSddIf sr ……………… (2) The following non-dimensional groups were derived using non-dimensional analysis.

SX =1 ; cX =5 ; s

r

dd

X =3 ; 24

Igd

X s=

cX =5 ………………………………….. (3)

No direct correlation was found among the above groups. However, the non-dimensional groups, X6 and X7 derived below appear to showed a reasonable correlation.

5326 .. XXXX = ; 21

47

XX

X = ……….. (4)

The variation of X7 with X6 is shown in Figure 4. Although the data points show a significant scatter, a clear trend a clear trend is noticeable. Using this relationship, a new equation to calculate the rate of soil erosion was derived.

……… (6)

Figure 4. Variation of X7 Vs X6

⎥⎦

⎤⎢⎣

⎡⎥⎦

⎤⎢⎣

⎡=

−

cddI

ISgd

Eqr

ss ρ46.1

2294.4

Figure 5. Comparison of erosion rates measured with that of computed values

The comparison of erosion rates computed using the above equation is compared with the experimental values in Figure 5. The deviation of results from the actual could be partly attributed to the factors that are difficult to control during the tests such as, initial moisture content and compaction of soil layers.

Conclusions Based on the extensive laboratory experiments, a new equation was proposed to estimate rainfall induced soil erosion. The equation derived here can only be applicable for clayey soils without plant cover. However, to verify the applicability of this equation, more experiments are needed with additional parameters used such as, soil types, bed slopes and rainfall intensities. Also, the effect of other parameters on soil erosion, which were not considered in this study, should also be studied. In addition, the proposed equation needs to be tested using field data.

Figure 3. Experimental set-up


183

A Non-Dimensional Approach to Predict Bed Load Transport in Unsteady Flow

P.C. Ranasinghe, K.P.P. Pathirana* and U.R. Ratnayake

Department of Civil Engineering, Faculty of Engineering, University of Peradeniya Introduction Knowledge of sediment transport is important as it influences many commonly encountered problems in rivers, streams and reservoirs etc. In this study, a series of laboratory experiments were carried out to measure hydraulic parameters and bed load transport rates in unsteady flows. Although there are several formulae available to predict bed load transport under steady uniform flow conditions, so far no reliable method has been developed to estimate bed load transport due to unsteady flows, which is generally the case in alluvial channels (Chang, 1988).

The objective of this study is to relate the bed load transport rates due to the governing hydraulic parameters in unsteady open channel flow.

Experimental procedure and set-up The experiments were carried out in a 10 m long, 0.4 m wide, and 0.5 m deep, rectangular flume in the Hydraulics Laboratory of the University of Peradeniya. Figure 1 shows a schematic diagram of the experimental set-up. The fixed and the movable beds of the flume were prepared with natural sand grains and fine

gravel with a size distribution of 2 to 8 mm. The flume consists of a sediment trap that collects the transported sediment to a container. The container is suspended through a load cell. The accumulated weight of sediment given by the load cell was continuously recorded in a computer through an A/D converter.

Sediment transport rates were measured for 96 different unsteady flows. These unsteady flow generated by passing six different hydrographs over each of 16 steady base flows. The base flows were established by passing four different water discharges obtained by different positions of the valve V1, in four different channel slopes. The six different hydrographs were generated by controlling the valve V2. At the upstream end of the channel, sediment was fed at a suitable rate to match with the entraining rate, using a sediment feeder. Water depth variations were recorded at a section 5.5 m downstream of the channel.

Results and discussion The bed load transport due to unsteady flow can be expressed by the non-dimensional relationship;

Main Supply

P2P1

FGBCT

ST

V1

V2

V3

LC

SFLA

DG

MGBUT

Figure 1: Experimental set-up

Main Supply

P2P1

FGBCT

ST

V1

V2

V3

LC

SFLA

DG

MGBUT

Main Supply

P2P1

FGBCT

ST

V1

V2

V3

LC

SFLA

DG

MGBUT

Figure 1: Experimental set-up

CT – Collection tank DG – Depth Gauge FGB – Fixed gravel bed MGB – Movable gravel bed LA – Lifting arrangement LC – Load cell SF – Sediment feeder ST – Sediment trap UT – Upstream tank P1, P2 –Pumps V1, V2, V3 –Valves


184

where, Quns = bed load transport rate due to unsteady flow, yp = peak flow depth, yb = base flow depth, ρ = fluid density, ρs = sediment density, S = channel slope, DT = total time period of hydrographs, d50 = mean grain diameter, and g = gravitational acceleration.

The above relationship can be simplified by incorporating Einstein’s bed load parameter φ ,

flow intensity parameter bψ , unsteady flow parameter Y* and hydrograph parameter HYDP (Kabir, 1993) in the following form,

[ ]HYDP,Y,F *bψ=φ (2)

where,

Sy

d

b

50s

b

⎥⎦

⎤⎢⎣

⎡ −

=ρ

ρρ

ψ (3)

21

350

ss

uns

gd

Q

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛ −=

ρρρ

ρ

φ (4)

b* Y

YY = (5)

( )( )2

b*

pbp

DTu

yyy2HYDP

−= (6)

Figure 2. Verification of derived formula with experimental data

( ) ( )( )

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

=2

150

21

5050213

50

,,,,,,d

gDTyDTg

yty

Syy

dy

dy

Fgd

Q

b

p

sb

pb

s

uns δδ

ρρ

ρ

(1)

R u n N o . M B 2 8

0

5 0

1 0 0

1 5 0

2 0 0

0 2 0 4 0 6 0 8 0 1 0 0

T im e / (s )

Bed

load

tran

spor

t / (g

/m/s

)

K a b ir ( 1 9 9 3 )

N e w F o r m u la

R u n N o . M B 3 1

0

5 0

1 0 0

1 5 0

2 0 0

0 2 0 4 0 6 0 8 0 1 0 0

T im e / (s )

Bed

load

tran

spor

t / (g

/m/s

)

K a b ir ( 1 9 9 3 )

N e w F o r m u la

R u n N o . M B 5 6

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0

T im e / (s )

Bed

load

tran

spor

t / (g

/m/s

)

K a b ir ( 1 9 9 3 )

N e w F o r m u la

R u n N o . M B 7 0

0

5 0

1 0 0

1 5 0

2 0 0

0 2 0 4 0 6 0 8 0 1 0 0

T im e / (s )

Bed

load

tran

spor

t / (g

/m/s

)

K a b ir ( 1 9 9 3 )

N e w Fo r m u la


185

Here, Sgyu bb =* and y denote instantaneous water depth. The derivative

ty

∂∂

represented in formulating one of the non-

dimensional parameters in Eq.(1) has been incorporated into the HYDP specified in Eq.(6).

In the present study, an approximate linear relationship is proposed based on the analysis of the observed unsteady flow bed load transport rates for all 96 hydrographs.

3*21 )()( cYcc b ++= ψφ (7)

The coefficients c1, c2 and c3 were obtained as functions of the HYDP parameter, as given below;

c1 = - 0.00237 / ( HYDP×104 ) 2.34 (8) c2 = 0.05160 / ( HYDP×104 ) 1.85 (9)

c3 = - 0.00789 / ( HYDP×104 ) 2.28 (10)

The relationship was verified using four sets of experimental data collected from previous studies (Kabir,1993) as shown in Figure 2. It can be observed that the transport rates predicted by the newly developed formula are in good agreement with the actual transport rates.

Conclusions By analyzing the observed bed load transport data, through non-dimensional parameters, it can be concluded that the bed load transport due to unsteady flow has a linear relationship with Einstein’s bed load parameterφ , flow intensity parameter bψ and unsteady flow parameter Y*, in which the coefficients are related to the hydrograph parameter HYDP.

References Chang, H.H. (1988) Fluvial Processes in River

Engineering, John Wiley and Sons, Inc., 133-141.

Kabir, M.R. (1993) Bed load transport in unsteady flow, PhD thesis No. UDC 532:551.31, Katholieke University of Leuven, Belgium.


186

Entrance Zone Effect on the Sediment Trapping Efficiency in Desilting Tanks of Run-of-River Type Mini-Hydropower Plants

U. Rathnayake, M.R.T.S. Harishchandra and S.B. Weerakoon*

Department of Civil Engineering, Faculty of Engineering, University of Peradeniya Introduction Development of run-of-river type mini-hydropower plants is receiving increased attention in Sri Lanka at present owing to the incentives announced for developers of renewable power generation projects during the last decade by the Sri Lankan government. The sources for most of the run-of- river type mini hydropower plants are mountainous streams where the discharges experience significant seasonal variation with frequent flash floods. The catchments of these streams are generally steep and face an increasing trend of soil erosion due to cultivation and other human activities. Therefore, the stream flows carry high sediment loads during seasonal floods. This sediment-laden flow enters the headrace canals feeding water to the turbines of the min-hydropower plants. Sediment in the water passing through the turbines with high velocity erode the contact surfaces of turbine components. The erosion of turbine components leads to a drop in hydraulic efficiency and to a high maintenance cost of the turbines.

Removal of sand carried with the flow in the headrace canals of run-of-river mini hydropower plants is therefore an important issue for the developers to reduce the maintenance cost of the turbines (Singal and Ranendra, 2006). Introduction of a de-silting tank in series with the headrace canal is one of the commonly used techniques for this purpose. De-silting tanks are designed as settling basins to settle sediment greater than a targeted size (Janssen, 2004).The shape and the size of the de-silting tank are major factors affecting the sand trapping efficiency of the de-silting tank. Several empirical and semi-empirical relations for the efficiency of sediment removal of de-silting tanks have been obtained (Ranga Raju et al., 1999). Ranga Raju and Kothyari (2004) provide an empirical relation for efficiency based on analysis of all the available data where efficiency is related to the cross sectional areas of the de-silting tank and the approach channel and the shear velocity in the de-silting tank. However, the effect of the shape of the de-silting tank on the

efficiency of sediment removal has not been given attention. This paper presents the results of a series of laboratory experiments carried out using scale model of a de-silting tank to investigate the effect of the flare angle of the entrance zone on the sand trapping efficiency of de-silting tanks.

Methodology Parameters of the mini-hydropower plant were selected to represent the plants installed in the country: discharge = 3 m3/s, headrace canal width =1.5 m, slope = 1:1000, flow velocity = 1.5 m/s and Manning’s coefficient = 0.012, target size of settling particles = 0.3 mm, de-silting tank size 15m×6m×2m. The laboratory model test was carried out based on Froude similarity using a 1: 6 scale model and sand in 90 - 125 μm range was used as scaled sediment size (65 μm), which falls into the silt region. The particle Reynolds number was in the laminar region. The model was built of plywood in the outdoor modeling yard of the Hydraulics Laboratory, University of Peradeniya and the de-silting tank comprised a tapered entrance zone followed by a rectangular tank as shown in Figure 1. Tests were conducted by changing the expansion angle of the entrance zone to 7, 10, 20, 30 and 90 degrees while keeping the length of the tank constant. Tests were repeated for three discharge rates, 15, 20 and 25 l/s, corresponding to different admission ratios of the prototype. Sand was fed to the upstream of the canal to maintain dynamic equilibrium in the canal bed. Sand trapping efficiency was calculated by measuring the sand trapped inside the tank and sand supplied to the tank.

Results Figure 2 presents the variation of sediment removal efficiencies with the expanding angle for three discharges of the canal. The figure shows that the sediment trapping efficiency of the de-silting tank depends strongly on the expanding angle at the entrance. As the angle decreases in the range of 7 to 90 degrees, the trapping efficiency increases from 60% to 80%.


187

However, as the flow entrance angle is decreased, the construction cost of the de-silting tank increases and therefore the optimum entrance angle can be decided only after a cost analysis. When the discharge through the tank is below the design value the sediment removal efficiency increases.tank increases and therefore the optimum entrance angle has to be decided only after a cost analysis. When the discharges through the tank is below the design discharge, the sediment removal efficiency increases.

Conclusions The entrance zone of the de-silting tanks has a considerable impact on the trapping efficiency of the sediment in the de-silting tanks. The trapping efficiency of the tank increases with the reduction of the expansion angle of the entrance zone in the de-silting tanks. The optimum expansion angle is found to be about 10 degrees. Nevertheless, further investigations

covering different sediment sizes are recommended.

References Janssen, R.H.A. (2004) Analysis and design of

sediment basins, 8th National Conf. in Hydraulics and Water Engineering, Institution of Engineers, Australia.

Ranga Raju, K.G., Kothyari, U.C, Srivastav, S. and Saxena, M. (1999) Sediment removal efficiency of settling basins, J. Irrigation and Drainage Engineering, ASCE, 125(5).

Ranga Raju, K.G. and Kothyari, U.C. (2004) Sediment management in hydroelectric projects, Impact of silt on hydro turbines, Himalayan Small Hydropower Summit, Dehradun, India.

Singhal, S.K. and Ratnendra, S. (2006) Impact of silt on hydro turbines, Himalayan Small Hydropower Summit, Dehradun, India.

Figure 1. Part of testing set up

50

55

60

65

70

75

80

85

90

0 10 20 30 40 50 60 70 80 90Expanding Angle (Deg)

Trap

ping

Effi

cien

cy (%

)

Q=15 l/sQ=20 l/sQ=25 l/s

Figure 2. Variation of sediment trapping efficiency with flaring angle


188

Flow Modeling of the Maha Oya at Peradeniya

D.M.A.G.B. Dissanayaka, U.J. Dissanayaka, D.A. Sachindra and S.B. Weerakoon*

Department of Civil Engineering, Faculty of Engineering, University of Peradeniya

Introduction The Maha Oya, which is a water way through the University of Peradeniya, originates from the Hanthana mountain range and discharges to the Mahaweli River near the university gymnasium. The catchment of Maha Oya covers about 5.2 km2. Understanding the flows in the Maha Oya is important as it supplies water to the Peradeniya Botanical Gardens and to many cultivations including nurseries and contributes to the pleasing environment of the main campus, and also, to plan mitigatory measures against possible damages to university infrastructure due to seasonal floods and poor water quality in it during seasonal low flows.

This study is focuses on the setting up of a rainfall- runoff model to estimate the discharge of the Maha Oya. It includes the calibration and verification of the HEC–HMS (Hydrologic Engineering Centre of US Army Corps Engineers Hydrological Modeling System) for the catchment.

The HEC-HMS hydrological modeling software has been used for the study of hydropower optimization in Sri Lanka. As an example, for the flood-rainfall analysis of Broadlands hydropower project the software has been utilized. For the flood analysis, the unit hydrograph technique (Snyder’s unit hydrograph) in the HEC-HMS has been used since it is simple and only a few unknown parameters had to be figured out.

Methodology Modeling of the Maha Oya Catchment using HEC-HMS mainly includes two steps: the catchment’s model calibration and the verification of the results. To set up the model, catchment topographic, geologic and land use details were collected. Since the catchment is ungauged a stream flow gauge was set up. The stage of the stream was measured on a daily basis and converted to discharge using the rating curve established. Daily rainfall data were obtained from the Gannoruwa rainfall recording station. Daily flows in the Maha Oya

and daily rainfall were obtained from 01/11/2006 to 15/06/2007.

The set of data from 01/11/2006 to 30/04/2007 was used for the model calibration and the data from 30/04/2007 to 15/06/2007 for model verification. The model parameters were optimized so that the simulated hydrograph matched the observed hydrograph during the calibration. The optimized parameters so obtained were used for model verification.

Results and discussion Calibration of the model was done by running the HEC-HMS model employing the constant monthly base flow method and the Clark unit hydrograph method with an initial loss of 20.32 mm, a constant loss rate of 25 mm/h, a storage coefficient of 0.8 h, and with a catchment imperviousness of 20% and time of concentration of 2.3 h. Figures 1 and 2 compare the simulated and observed stream flows of the Maha Oya close to the University mosque.

The model can be used for the simulation of Maha Oya flow for rainfall data after the month of June, since the calibration has been done for the relatively rainy months such as November and December.

Concluding remarks A rainfall-runoff model for estimating stream flow of the Maha Oya at Peradeniya University premises was developed. This calibrated model can be used as a tool for estimating discharge characteristics of the Maha Oya necessary for the planning constructions on the banks of the stream and for the estimation of potential withdrawals from it.

References Brassington, R. (1995) Field Hydrology, John

Willy & Sons Ltd. Fleming (1975) Computer Simulation

Techniques in Hydrology, Elsevier Environmental Science Series, Elsevier publishers, Ed. 2.


189

Subramaniya, S (1997) Engineering Hydrology, Tata McGrew – Hill publishing company Ltd. Ed. 2.

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

November

December

January

FebruaryMarc

hApri

l

Month

Disc

harg

e ( f

t3 /sec)

Observed discharge ( Cubic feets per second)

Simulated discharge

Figure 1. Simulated and observed stream flow of the Maha Oya for the calibration period

0.00

5.00

10.00

15.00

20.00

25.00

May June

Month

Dis

char

ge (f

t3 /sec

)

Observed dischargeSimulated discharge

Figure 2. Simulated and observed stream flow of the Maha Oya for the verification period


190

Issues Arising from Water Encroachments along Hurulu Wewa Feeder Canal

A. Abeynayaka1, D.R.I.B. Werellagama2* and G.N. Paranavitana3 1Kaluganga Agriculture Development Project EIA Team, Centre for Environmental Studies,

University of Peradeniya 2Department of Civil Engineering, University of Peradeniya

3Natural Resource Management Services, Mahaweli Authority of Sri Lanka

Introduction Water encroachment is unauthorized tapping of irrigation water provided for downstream users. In Sri Lanka, the Mahaweli Development Scheme, a major development project in the country’s history, could not achieve some of its objectives owing to this problem. Attempts by engineers and other government officers to solve this problem are prevented by the intervention of local politicians. This paper studies the fate of the water in main canal feeding Mahaweli water to the Hurulu Wewa (HW) in Anuradhapura district of Sri Lanka.

The dry zone of Sri Lanka has been the home of one of ancient “hydraulic civilizations” in monsoon Asia (Wittfogel, 1957). It consists of interconnected minor irrigation tanks collectively referred to as a cascade (Madduma Bandara, 1985). These cascades were formed not only as water storage and irrigation practice but also as a system for proper land use, planning and operation, and maintenance.

Materials and methods The study covers the experiences of the authors during the EIA study of Kaluganga Agricultural Development Project.

Results and discussion The 33 km long HW feeder canal (HFC) was designed to convey 4.3 m3/s of water throughout the year to the HW (Lahmeyer International, 2004). The canal discharges the water into Yan Oya (a natural stream), which crosses three minor tanks including Thalkote, Hiriwadunna, and Habarana (TH&H) with command areas of 80, 64, 40 ha, respectively (MASL, 2005). At the project planning stage, the land around the banks of the canal was undeveloped and the project planners of 1960s and 1970s ignored future land development possibilities and water requirement for those lands. Hence the project planners assumed that the bulk of the flow (except minor losses such

as seepage and evaporation) would reach the HW.

Figure 1. Farmlands leading up to the dam

Mahaweli Authority of Sri Lanka (MASL), Department of Agrarian Services (DAS) and Irrigation Department (ID) are managing the major three components, HFC, TH&H and other minor irrigation schemes, and HW respectively. Lack of interaction among those institutions is a problem. When the MASL releases water to HFC the water passes through tanks managed by farmer organizations (FO) under DAS. At the beginning the cultivated area under those tanks (TH&H) was limited due to low availability of water. Yet, when the HFC passed through those tanks, the water availability was not a constraint any more. It destroyed the concept of “tank capacity controlled farmland area” (Abeynayaka et al., 2007). Farmers encroached the land as they could. It continued up to the dam in some places (Figure 1) by removing the interceptor (the marshy land between the dam and the paddy field), which acts as a salt trap. This has made a severe impact on the sustainability of the farm lands.

On the other hand the lands around the HFC were developed by taking water from HFC. Since HFC is a contour canal along most of its path, farmers on the low side started to take water out with siphons (now the lands are developing on the high side also using solar


191

pumps). Once a siphon is set up, water generally is allowed to flow out continuously to sustain the siphon function. This consumes a considerably larger amount of water than a well designed outlet irrigation canal, which can also be used as a discharge control device.

Figure 2. Water encroachments

The design flow rate of 4.3 m3/s gives a water flow of 44.6 MCM (million cubic metres) for a four month cultivation season (“Yala”) and 55.7 MCM for a cultivation season of five months (“Maha”). Yet the HW water budget shows a very low inflow to the HW (Figure 3) starting from 1985. On many occasions the HFC flow is far below the designed flows due to water pilferage.

Owing to water scarcity in the HW command area, the farmer organizations (FO) of HW have campaigned to adopt a water management plan for the HFC. In late 1990s’ FO of HW and

HFC, ID, and MASL discussed and agreed on a water management plan, providing more water to HW. HW farmers now provide labour for the maintenance of the upstream canals and the labourers also serve to police unauthorized tapping. Yet the informal agreement did not consider improving water controlling structures or land use planning of the area. When MASL officers removed the siphons, local politicians forced them to put the siphons back. This is a case of the state acting against the promises made to the donors, to provide water to HW. Measures to prevent recurrence of such things are important in future schemes.

Conclusions Improper management including poor catchment management and land use planning reduces the productivity of water resources and land. Future land developments must take these facts into account at project planning stage itself. Water management policy must be coupled with land management and land development.

References Abeynayaka, A., Werellagama, D.R.I.B.,

Yatawara, S.C.B. and Paranavitana, G.N. (2007) Lessons on water management; Past to the Future, International forum on water environmental governance in Asia, Thailand, 26-32.

Figure 3. Inflow data to HW in Yala-Maha two seasons

0

5

10

15

20

25

30

35

40

45

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Season

HFC

inflo

w /(

MC

M)


192

Lahmeyer International (2004) Feasibility study report of Kaluganga development project, Mahaweli Authority of Sri Lanka, Sri Lanka, 3_134.

Madduma Bandara, C.M. (1985) Catchment ecosystems and village tank cascades in the dry zone of Sri Lanka; A time tested system of land and water resources management, Strategies for River Basin Management, Lundqvest J., Lohm U., and Falkenmark,

M.D. Reidel Publishing Company. DordrecHW, Holland, pp 99-113.

MASL (2005) Mahaweli Authority Huruluwewa feeder canal management office database, Mahaweli Authority, Sri Lanka.

Wittfogel, K.A. (1957) Oriental Despotism: A Comparative Study of Total Power, Yale University Press, New Haven, USA.


193

Study of Cassava Starch Hydrolysis by α-Amylase and an Airborne Mould Culture

W.A.L.D. Wickramasinghe1, S. Sotheeswaran1, U.S.K. Weliwegamage1, S. Rajapakse2 and C.S. Kalpage3*

1Institute of Chemistry Ceylon, Rajagiriya 2Department of Molecular Biology and Biotechnology, Faculty of Science, 3Department of

Chemical and Process Engineering, Faculty of Engineering, University of Peradeniya

Introduction

Ethanol is an excellent source of energy which can be produced by microbial fermentation of glucose. Starch can be used as a precursor in glucose processing by chemical or biological hydrolysis (Amutha and Gunasekaran, 2001). Cassava is a woody shrub containing starch that is extensively cultivated as an annual crop in tropical and subtropical regions for its edible tuberous root (Encyclopedia Britannica, 2007).

It was reported that α-amylase is capable of breaking down starch to a mixture of sugars and amyloglucosidase to produce glucose from dextrin in the sugar mixture (Waliszweski et al., 1992). This study investigates the use of a commercially available α-amylase and an airborne mould culture (as a source of amyloglucosidase) for the hydrolysis of cassava starch at different processing conditions.

Materials and methods

Materials Cassava and α-amylase were purchased from the local market. Aspergillus niger was produced in the microbiological laboratory via a mixed airborne fungal culture. Dinitrosalicylic acid reagent, anthrone, 95% H2SO4, 72% perchloric acid, anhydrous glucose, 0.1M HCl, agar, potassium sodium tartrate, Na2SO3 and potato extract were supplied by the Institute of Chemistry, Ceylon. All chemicals used were of analytical grade.

Methods The study involves several laboratory experiments. Methods are briefly given below. Starch contents were estimated by the method of McCready et al., (1950). Glucose contents were measured using the dinitrosalicylic acid (DNS) method (Wang, 2007).

Cassava Flour Processing: Cassava flour was produced by the wet milling of fresh cassava

roots. The process involved washing, rasping, pulping, grating, starch washing, dewatering, drying, and milling of cassava.

Liquefaction: Liquefaction was carried out by the method proposed by Amutha and Gunasekaran (2001) using heat stable α-amylase. Initially, starch slurries were prepared by dissolving cassava flour in distilled water and pH was adjusted to 5.0- 5.5 using HCl. Slurries containing starch concentrations; 20% (samples A), 10% (samples B) and 5% (samples C) were prepared. Then, α-amylase was introduced into samples contained in titrimetric flasks. Enzyme to flour weight volume ratio was maintained at 1:20. CaCl2 was added in small amount (0.3 g/l) in order to stabilize the enzyme. Glucose concentrations in above samples were measured after subjected to following heat treatment (HT) processes:

HT 1: Maintained at 65 0C for two days then heated up to 100 0C for 10 min and kept at 90 0C for 3 hours.

HT 2: Heated up to 75 0C and held at this temperature for 3 hours with agitation.

HT 3: Heated up to 100 0C and held for 10 min and at 90 0C for 3 hours with agitation.

Saccharification: After liquefaction, the pH of the slurry was reduced to 4.5- 4.8 and solutions were cooled to 30 0C. The liquefied starch containing flasks were inoculated with Aspergillus niger and incubated at 30 0C for 2-5 days.

Growing of Aspergillus niger: A microbial culture identified as Aspergillus niger was obtained on potato dextrose agar (PDA) medium, pH 4.8, after selectively isolating them from a mixed airborne fungal culture grown on PDA medium at room temperature. Aspergillus niger was identified by referring to the Commonwealth Mycological Institute descriptions of pathogenic fungi and bacteria. The slants of Aspergillus niger were stored at


194

4 0C in the refrigerator and were sub-cultured twice per month.

Results and discussion When starchy slurry is heated above 60 0C, the starch containing granules get swelled and rupture and are gelatinized. The gelatinized cassava starch gets partially hydrolyzed rapidly by heat stable α-amylase in liquefaction. The partially degraded starch chains are called dextrins, which are suitable as starting materials for the later steps in ethanol production.

For this study cassava powder was prepared from cassava root by a wet milling process. The average cassava powder yield was 375 g/kg of fresh cassava. It was estimated that the starch and glucose contents in dry cassava powder are 19.55 and 3.48 g/100g, respectively.

Hydrolysis of cassava starch was studied under none different conditions using α-amylase as explained before; three different starch concentrations under three thermal processing methods. The selected sample size was 30 ml. After the liquefaction stage, the air borne fungal culture which was identified as Aspergillus niger was introduced to each of the sample. The change in glucose concentration

was monitored after liquefaction and saccharification. Results are given in Table 1. Samples are denoted by an English letter and a number. The letter refers to starch concentration and the number indicates the thermal treatment process. Conversion of starch to glucose in each test sample is shown in Table 2.

According to Table 2, the highest glucose conversions were found among samples ‘C’ (above 54%) in which the initial starch concentrations are only 5%, while samples with highest initial starch concentrations (A) have reported the minimum Conversion Yields (less than 21%). The best result; 57.6% was obtained with sample C3 which was prepared by the method explained before.

Decreasing glucose conversion yield with increasing initial starch concentration is attributed to a possible inhibition activity taking place in starch solutions. Vasquez et al., (2004) reported that plants contain anti bacterial and anti fungal substances (such as polyphenolics, cyanogenic compounds and peroxidases) in order to inhibit the bacterial and fungal attacks. Therefore, it seems that low concentrated starch solutions are more suitable for the

Table 1. Concentration of glucose at different stages of the process

Process Stage Concentration of glucose in samples, mol dm-3 After Liquefaction 0.19 0.19 0.18 0.14 0.09 0.13 0.06 0.07 0.08

Saccharification After 2 days After 5 days

0.22 0.22

0.17 0.22

0.20 0.23

0.17 0.17

0.14 0.18

0.17 0.16

0.11 0.15

0.13 0.15

0.10 0.16

Sample A 1 A2 A3 B1 B2 B3 C1 C2 C3

Table 2. Starch to Glucose Conversion yields

Conversion Yield, g glucose/100 g starch Process Stage A 1 A2 A3 B1 B2 B3 C1 C2 C3

After Liquefaction 17.1 17.1 16.2 25.2 16.2 23.4 21.6 25.2 28.8

Saccharification After 2 days After 5 days

19.8 19.8

15.3 19.8

18.0 20.7

30.6 30.6

25.2 32.4

30.6 28.8

39.6 54.0

46.8 54.0

36.0 57.6


195

enzymatic hydrolysis in order to produce ethanol. However, the use of diluted solutions in a biological reactor could be uneconomical as large quantities of reactants are needed to be handled per unit production of ethanol.

Conclusions The best sugar converting percentage in the liquefaction process was obtained when, 5% starch slurry was processed at 100 0C for 10 minutes followed by 90 0C for 3 hours with agitation. The microbial strain that cultured in the laboratory was found capable of converting liquefied cassava starch into glucose. Sugar concentration continued to rise even after 5 days of inoculating the fungus to the medium. The maximum yield obtained after 5 days was 57.6 g glucose/100 g starch.

Acknowledgements

The authors wish to thank the Institute of Chemistry Ceylon, Department of Molecular Biology and Biotechnology, and the Department of Chemical and Process Engineering of the University of Peradeniya.

References Amutha, R. and Gunasekaran, P. (2001)

Production of ethanol from liquefied

Cassava starch using co-immobilized cells of Zymomonas mobilis and Saccharomyces diastaticus, Journal of Bioscience and Bioengineering, 92(6),560- 564.

Encyclopedia Britannica (2007) Cassava, www.britannica.com/eb/article-9020643/ cassava accessed on 02/10/2007.

McCready, R.M., Guggolz, J., Silviera, V. and Owens, H.S. (1950) Determination of starch and amylose in vegetables/Application to peas, Analytical chemistry, 1156.

Vasquez, R.G., Day, R., Bushmann,H., Randles, S., Beeching, J.R. and Cooper, R.M. (2004) Phenyl propanoids, phenyl Alanine ammonia lyase and peroxidases in elicitor challenged Cassava (Manihot esculanta) suspension cells and leaves, Annels of Botany, 94, 87-91.

Waliszweski, K.N., Alvarado, M.G. and Medina, J.D.L.C. (1992) Kinetics of enzymic hydrolysis of cassava flour starch - optimization and modeling, International Journal of' Food Science and Technology, 27, 465-472.

Wang, N.S. (2007) Glucose Assay by Dinitrosalicylic Colorimetric Method, Department of Chemical and Bimolecular Engineering University of Maryland.


196

Cross-Sectional Assessment of Chlorpyrifos in a Small Stream Running Through a Densely Cultivated Area in Kandy District

A.M.W. Menike*, C.S. Kalpage and. R. Shanthini

Department of Chemical and Process Engineering, Faculty of Engineering, University of Peradeniya

Introduction Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothionate) is a highly active, non-systemic pesticide applied to control a wide range of soil pests and arthropods on various crops including vegetables, citrus, cereals, maize, potato and tobacco. Chlorpyrifos containing pesticides are commercially available as Durban, Lorsban, Syren, Commando, Judo, Bullet, Chlofos, Unifos, Loseban, Patas, Lidoband, Dhanwan, Dorson and Omexan in the local market. This chemical is moderately toxic following acute oral, dermal, and inhalation exposures (Zhao et al., 2004). The embankment of Kiwullinda Oya (a small stream, 9.5 m wide and 1 m average depth), running through the Marassana area in Kandy District and feeding the Victoria reservoir, is densely cultivated with vegetables and paddy. Chlorpyrifos, with 40 days half-life in buffers at 30 oC (WHO, 2002), is one of the popular pesticides in use in Marassana. Therefore, the probable presence of chlorpyrifos in surface and ground water at Marassana, especially in the Kiwullinda Oya, has long been suspected. The objective of this research was to quantify chlorpyrifos concentrations (if present) in the water of Kiwullinda Oya stream basin. It is important because, according to the discharge water quality standards (CEA, 1990), no pesticide should be detected in surface water even in trace amounts.

Methodology Five random water samples were collected from the Kiwullinda Oya in May 2007, which was during off-peak pesticide application period. On June 16th, 2007, which fell within the peak pesticide application period, 14 water samples were collected over a 3 km stretch of Kiwullinda Oya. The sampling locations are shown in the schematic diagram of Figure 1. From each sampling point, a 600 ml sample of water was collected in a 1-litre amber glass bottle with a glass lid, and the samples were transported to the Analytical Laboratory of the department within 4 hours of the sample collection. Samples were refrigerated below 5 oC until the time of analyses. Water samples were analyzed for the presence of chlorpyrifos using a High Performance Liquid Chromatograph (HPLC) method (CIPAC 1 C, 1985). In this method, the target compound, chlorpyrifos, was extracted using dichloromethane. The extract was then concentrated and dried by means of blowing ambient air, which is at 35 0C or below, over the extract. The residue was then dissolved in a mobile phase (acetonitrile). The solution so prepared was injected to the HPLC and the peak area readings were obtained. These readings were then converted to concentrations by use of calibration charts, which were generated in this study itself.

Figure 1. Schematic diagram of the 14 sampling points and the relative positions of inlets feeding

significant amount of water to the investigated stream

1 2 3 4 5 6

78

10 11 12

13 14

9

Sample points

Anicut across the river

inlet inlet

inletinlet inlet inlet inlets

Reservoir inlet of stream


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Results Chlorpyrifos in environmental wastewater samples were extracted using Dichloromethane for two reasons: (1) to prevent impurity contamination in HPLC column (2) to increase chlorpyrifos concentration in samples to HPLC measurable level. Figures 2(a) and 2(b) show charts used for HPLC calibration and extraction efficiency estimation, respectively. Both graphs exhibit linear relationships (regression coefficients are 0.9387 and 0.9913). The coefficients of linear regression shown in the figures were used in the conversions of HPLC peak area to chlorpyrifos concentration in wastewater samples. All measurements used for calibration curves were duplicated.

Chlorpyrifos concentrations of the 5 random samples collected from the stream during off-peak pesticide application period are 0.000, 0.017, 0.058, 0.116 and 0.118 µg/l. Chlorpyrifos concentrations of the 14 samples collected during peak pesticide application period are given in Figure 3.

Discussion Significant amounts of the pesticide, chlorpyrifos, were detected in the water samples in the Marassana vegetable and paddy cultivation area during both the off-season and peak-season of pesticide application. The maximum detected concentration during off-season and peak-season were 0.12 µg/l and 2.48 µg/l, respectively.

(a)

y = 0.0316xR2 = 0.9386

0

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0 500 1000Chlorpyrifos Concentration, μg/l

Peak

are

a, m

AU

(b)

y = 0.7293xR2 = 0.9913

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1.5

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0 1 2 3 4Concentration in wastewater, μg/l

Con

cent

ratio

n in

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ract

, μg/

l

Figure 2. Calibration curves for (a) HPLC peak area versus chlorpyrifos concentration, (b) chlorpyrifos concentration in extract versus chlorpyrifos concentration in wastewater

1413

12

11

10987

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54

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Distance along the stream, m

Chl

orpy

rifos

con

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n in

th

e st

ream

, μg

/l

Figure 3. Variation of chlorpyrifos concentration along the stream on a day during peak pesticide

application period


198

The chlorpyrifos concentration in the water sample collected from one of the community wells in this area was also as high as 0.79 µg/l. The highest chlorpyrifos concentration was detected at the sampling point 2 where several irrigated channels and field surface runoffs enter the stream. Comparison of concentration data (Figure 3) and the sampling locations (Figure 1) provides a telling relationship. Local peaks in concentrations are seen at points 2, 5, 7, 9 and 13, where main irrigated canals enter the Kiwullinda Oya. In the span of sampling points 13 to 14, surface runoffs from cultivated lands located at high elevations enter the stream water at no specific location, which keeps the chlorpyrifos concentration approximately a constant. Stream water at points 10 and 12 are diluted with large quantities of fresh water entering via channels, which are not running through cultivated land. It was observed that the both sides of stream banks between point 10 and 11 were cultivated with vegetables. The high peak at point 11 is therefore, attributed to accumulation of pesticide contaminated water seeping through the stream banks.

Conclusions Though, according to Sri Lankan regulations, not even trace amounts of pesticides should be detected in discharge water from industrial and agricultural applications high concentrations of chlorpyrifos (up to 2.48 µg/l) have been observed along a 3 km stretch of Kiwullinda Oya, a small stream running through the cultivated lands in Marassana. It is apparent that chlorpyrifos entered the stream with the water from irrigation channels and surface runoffs. It is found that the presence of chlorpyrifos in surface waters is not limited only to the peak, but also to the off-peak

pesticide application periods. The cross-sectional assessment of the chlorpyrifos reported in this paper is being repeated at present to study the variations in the concentration of chlorpyrifos in the stream with time.

Acknowledgements RG/2006/33/E, University of Peradeniya, is acknowledged for funding. Special thanks are due to the Pesticide Registration Office of the Department of Agriculture and to the technical staff at the Department of Chemical and Process Engineering for the technical support provided.

Reference CEA (1990) General standards for discharge

of effluents in to inland surface waters, Act no 47 & 56, Part 1, section 1, Gazette extraordinary of the Democratic Socialist Republic of Sri Lanka - 1990/02/02.

CIPAC handbook 1 C (1985) Collaborative International Pesticide Analytical council, 2028-2031.

WHO (2002) Geneva WHO Specifications And Evaluations For Public Health Pesticides, Chlorpyrifos O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate, World Health Organization publication, retrieved on 08/03/2006 from http://www.who.int/whopes/ quality/en/.

Zhao, Q., Gadagbui, B. and Dourson, M. (2004) Lower birth weight as a critical eVect of chlorpyrifos: A comparison of human and animal data, Regulatory Toxicology and Pharmacology, 42, 55–63.


199

Design of a Paddy Husk Charcoal Adsorption Unit for the Treatment of Parboiled Rice Processing Wastewater

S.M.W.T.P.K. Ariyarathna*, C.S. Kalpage and R. Shanthini

Department of Chemical & Process Engineering, Faculty of Engineering, University of Peradeniya

Introduction Soaking paddy in water until it attains a moisture content of 30 to 35% by weight is the key unit operation in parboiled rice processing. Wastewater exiting the soaking tanks of the rice mills generally registers chemical oxygen demand (COD) at a very high value, for example, 4500 mg/l, which is well above the permitted COD (< 250 mg/l) for wastewater discharged to surface waters in Sri Lanka (CEA, 1990). However, owing to the location of a majority of rice mills in the relatively environmentally-healthy rural areas of Sri Lanka, no stringent effluent control is imposed on these rice mills. As a result, a good number of the rice mills in Sri Lanka discharge their untreated rice mill effluent (RME) into surface waters, and thereby polluting them.

Since some of the pollutants in the RME are adsorptive, adsorbents such as activated carbon and paddy husk charcoal (PHC) could be used to selectively remove these substances from the wastewater. PHC, containing about 65% carbon is readily available at rice mills. It is a solid waste generated from the boilers which use the paddy husk waste originating from the milling section as fuel. In boilers, about one fourth of the paddy husk mass gets converted into PHC during combustion. It has been shown that PHC could successfully remove COD, pH, odour, colour and TDS in RME (Ariyarathna et al., 2004).

In this study, a detailed investigation was carried out to design PHC adsorption units for commercial-scale parboiled rice processing mills of capacity up to 10,000 kg/day of paddy. A design curve, constructed with the help of experimental data obtained from laboratory-scale PHC adsorption unit, was used to scale up for an industrial-scale fixed bed PHC adsorption column which could reduce COD from 4500 mg/l to 500 mg/l.

Materials and methods The wastewater sample was collected from the soaking tanks of a commercial rice mill situated in Kalawewa, Mahaweli H zone, Sri Lanka. The initial COD of the sample was measured to be 4500 mg/l and the pH was 4.5. PHC was also collected from the same mill, and sieved to separate particles of size 0.2 to 0.5 mm, which were used as the adsorbent in this study without subjecting to any pre-treatment. A column of 150 cm height and 2.7 cm diameter was fabricated with PVC conduit pipe. Of this column, a height of 120 cm was packed with 75 g of PHC, which was the adsorption media. Wastewater was passed through the bed at the experimentally determined optimum superficial velocity of 5 mm/min. Samples of the column effluent were collected at the bottom of the bed at selected time intervals, and their respective COD were measured. All experiments were at least duplicated. The data so obtained were used to construct the breakthrough curve, showing the profile of the column effluent COD against time; and the principles of adsorption column design were then employed for scale up for the industrial unit (Christie, 1993).

Results and discussion Figure 1 shows the breakthrough curve obtained with a 5 mm/min superficial flow velocity with the laboratory-scale PHC adsorption column. The ratio of COD of the wastewater leaving the column (c) to the COD of the wastewater entering the column (co = 4500 mg/l) was plotted against time. The long time taken for bed saturation (about 3600 min) shows that the rate of adsorption is relatively slow.

The levelling off of the breakthrough curve shown in the Figure 1 close to c/co =1 implies that the entire bed of PHC has come to equilibrium with the wastewater fed to it. In which case, according to theory, the total capacity of the PHC packed bed is proportional to the area between the


200

breakthrough curve and the vertical axis (denoted by A1 = 32). A value of COD is chosen for the column effluent, at which the column operation would cease. This value of the COD is known as the breakthrough COD. It was chosen be 225 mg/l which is below the permissible COD level of discharge water quality into surface water. Since the initial COD of the wastewater was 4500 mg/l, the ratio at the breakthrough point was 0.05, which was reached 240 min (i.e. 4 hours) from the commencement of the experiment, as shown in the figure. The area up to this point gives the usable capacity of the bed (denoted by A2 = 4). The ratio of the two areas, A2/A1, which is the fraction of the total bed capacity or length utilized up to the break point, becomes 0.125. Hence, usable length for selected bed was calculated to be 15 cm (= 0.125 x the PHC bed height). The unusable bed height which remains a constant as long as the superficial flow velocity remains a constant, was then 105 cm.

Table 1 summarises the results obtained for the laboratory-scale column and the corresponding scaled up values for the industrial-scale column for an operating time of three days using the procedure outlined in Christie (1993). Both the columns must have the same input and output CODs, as well as flow velocity during scale up.

The industrial columns were designed for the treatment of 33,000 l of wastewater, which is the maximum volume of wastewater produced per day by the rice-mill (chosen for this study). Therefore, three identical adsorption columns (throughput of each is 11,000 l/day) are needed to be operated simultaneously to treat the above wastewater. Table 1 shows that 677 kg of PHC is required to treat 33,000 l of wastewater with the bed being operated for 3 consecutive days.

Figure 1. Breakthrough curve obtained with the laboratory-scale PHC adsorption column.

0.05

C/C

o


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Table 1 Results obtained from laboratory-scale and the industrial-scale columns

Parameters Laboratory-scale adsorption column

Industrial-scale adsorption column*

Initial COD of the RME, mg/l 4500 4500

Final COD of the RME, mg/l 225 225

Flow velocity of wastewater, mm/min 5 5

Flow rate of wastewater, l/min 3×10-3 7.6

Height of the column, m 1.2 3.8

Diameter of the column, m 2.7×10-2 1.4

Operating (Breakthrough) time of the column, h 4 72

Unused Bed Height, m 1.05 1.05

Required amount of PHC, kg 75×10-3 677

*Three such columns are operated in parallel

However, the rice-mill chosen for this study generates a maximum of 625 kg of PHC per day. Therefore, the amount of PHC generated in the mill itself is not enough to reduce the COD of all the wastewater produced to 225 mg/l. On the other hand, with the available amount of PHC at the mill, the COD of all the wastewater generated could be reduced to 500 mg/l COD with the PHC bed of 1.4 m diameter and 3.6 m height.

Conclusions

The design of the industrial scale adsorption unit carried out in this study reveals that the COD of 33,000 l of wastewater produced in a parboiled rice processing facility could be reduced from a very high value of 4500 mg/l to 225 mg/l, using 677 kg of paddy husk charcoal. Three columns each of 1.4 m diameter and 3.8 m height, operated at a superficial velocity of 5 mm/min for 3 consecutive days, are required for this purpose. However, the rice mill of 10,000 kg/d capacity chosen for this study, producing a maximum of 33,000 l of wastewater, produces only 625 kg of paddy husk charcoal. Using this 625 kg of paddy husk, the strength of the wastewater could be

reduced from 4500 mg/l to 500 mg/l in an adsorption column of 1.4 m diameter and 3.6 m height operated at a superficial velocity of 5 mm/min for 3 consecutive days. Research is being carried out at present to reduce the COD from 500 mg/l to the permissible level of 250 mg/l or below by conventional wastewater treatment methods such as biological treatment or activated carbon adsorption.

Reference Ariyarathna, S.M.W.T.P.K., De Silva, W.P.M.,

Wimalasena, B.D.S.N. and Shanthini, R., (2004 ) Investigating the possibility of the use of paddy husk charcoal for the treatment of rice mill wastewater in Sri Lanka, Proceedings of the University Research Session, University of Peradeniya.

CEA (1990), General Standards for discharge of effluents into inland surface water, Gazette Extraordinary of the Democratic Socialist Republic of Sri Lanka, 1990.02.02: Part 1, Sect 1, page 26A.

Christie, J.G. (1993) Transport Process and Unit Operations, Prentice-Hall International, Inc, 3rd Edition.


202

Effect of Process Parameters on the Quality of Instant Tea

I.R. Samarathunga* and D.G.G.P. Karunaratne


Introduction Tea is the main agricultural export of Sri Lanka contributing around 15% to the total exports of the country. Sri Lankan tea is renowned as one of the best blends of tea available in the global market. The number of direct and indirect beneficiaries from the tea industry is considerable.

At present, Sri Lanka exports several varieties of tea including bulk tea, tea packets, tea bags, green tea, and instant tea. Among these, the demand for instant tea is continuously increasing. There are two main types of instant tea: hot water soluble instant tea and cold water soluble instant tea. (Abeysekera, 2005).

The principal operations carried out in manufacturing hot water soluble instant tea are extraction, filtration, evaporation, aroma stripping and aromatization, spray drying and packing. The main indicators of the quality of instant tea include particle size distribution, the total polyphenol content, the thearubigins to theaflavin ratio, and the brightness of the tea (Roberts and Smith, 2001).

In this work, the effect of the important process parameters such as extraction time, extraction temperature and evaporator temperature, on the quality of instant tea was examined.


Experiment planning As there were several variables under study and since the production of instant tea and analysis of the quality were expensive and time consuming, a two level factorial experiment design approach was employed to screen out the influential process parameters. The selected process parameters and the relevant levels are shown in Table 1. The upper and lower levels of each parameter were decided based on the range of process parameters used in the industry.

Table 1. Selected process parameters and levels

Production of instant tea Five liters of distilled water was pre-heated to the required temperature of the extractor as given in Table 1. Then 500 g of tea (tea grade of Broken Orange Pekoe Fannings) was added to pre-heated water, and the temperature was kept constant at the required extractor temperature for the required period of time while stirring. Then the tea brew was strained, and was evaporated in the climbing film evaporator at the Department of Chemical and Process Engineering, University of Peradeniya. The first 100 ml of vapour leaving the evaporator was condensed, collected and added back to the concentrated brew to simulate the aroma stripping operation. The evaporation was then carried out for 90 minutes. The concentrated tea brew was then spray dried at a constant temperature of 95 ºC in the spray dryer at the Food research institute, Gannoruwa. The resulting tea powder was then aseptically packed and sealed in triple layered aluminium foil bags to prevent possible moisture absorption.

Quality measurements The standard procedure for determining total Polyphenol level in instant tea was performed using a Folin-Ciocalteu Colorimetric reagent, with optical density measurements at 765 nm. (ISO working draft, 2005). The standard procedure for determining thearubigin and theaflavin in instant tea was implemented using

Level Parameter Lower

(-1) Upper (+1)

Extraction time /(min) Extraction temperature /(oC) Evaporator temperature /(oC)

10 75

85

20 85

95


203

isobutyl-methyl-ketone (IBMK) and sodium hydrogen carbonate by measuring optical density at 380 nm and 460 nm. (Roberts and Smith, 2001).

Calculation of quality measurement

Theaflavin and Thearubigin content were calculated from the optical density measurements at 380 nm while the brightness was calculated from the optical density measurements at 460 nm (Roberts and Smith, 2001). The total Polyphenol content was calculated from the optical density measurements at 765 nm. (ISO working draft, 2005).

Data analysis The calculated values for thearubigin content, theaflavin content, total polyphenol content and the brightness values were analysed using the factorial experimental method.

Results and discussion According to the factorial method, the most influential parameters stay as outliers of the

best-fit line in the plot of the normal probability against factor effect. (Montgomery, 1976)

By analyzing the four normal probability plots related to total polyphenol, theaflaving, thearubigin and brightness, the only outlier which deviates from the best-fit line is found in the plot related to total polyphenol, and it corresponds to the interaction of evaporator temperature. (Figure 1).

Interaction plots were drawn to identify significant interactions (Montgomery, 1976). The only significant interaction found was between extractor time and evaporator time. This is indicated in Figure 2. This interaction indicates that the Evaporator temperature has little effect at low Extractor temperature, but a large negative effect at high level of Extractor temperature. This may be due to the sensitivity of Thearubigin to high temperature. When both extractor and evaporator temperatures are high the exposure time of tea for high temperate increase, which leads to the destruction of Thearubigin.

Effect estimate

99.99

99.999.8

99 98

95

90

80

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9998

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90

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Figure 1. Normal probability vs effect estimate plot for Total Polyphenol


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Conclusions Among the three process parameters, extractor time, extractor temperature and evaporator temperature, analysed in this research, evaporator temperature was identified as the parameter which has the highest influence on the quality of instant tea.

References Abeysekera, S.A. (2005) Technical Feasibility

Study on the Manufacture of Hot Water Soluble Instant Tea, Tea Research Institute, Thalawakele.

ISO working draft (2005) Tea and Instant tea- Determination of total Polyphenols in tea- Part 1: Method using Folin – Ciocalteu colorimetric reagent.

Montgomery, D.C. (1976) Design and Analysis of Experiments, John Wiley and Sons.

Roberts, E.A.H. and Smith, R.F. (2001) The Phenolic substances of the manufactured tea, IX: The Spectrophotometric evaluation of tea liquors, Journal of the Science of Food and Agriculture.

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

-1.5 -1 -0.5 0 0.5 1 1.5

Extractor Temperature

Thea

rubi

gin

/%

Evp temt at 85C Evp temt at 95CEvp temp at 85C Evp temp at 95C

Figure 2. Interaction plot for Thearubigin at extraction time 20 min


205

Use of Light Absorption in the Fabrication of a Device for Measuring Ambient Black Carbon Concentration

N.M.N.V. Bandara, P.S. Palugaswawa and M.A. Elangasinghe*


Introduction Soot particles that contain black carbon are generated in combustion processes. Combustion of fossil fuel in automobiles is the major source of high levels of aerosol black carbon in urban areas (Ernesto et al., 2000). Studies have revealed that airborne fine soot particles, that have high catalytic, optical and electrical properties, not only harm human health but also influence global climate change (Gundel et al., 1984; Hansen et al., 1993).

High cost of ambient air sampling devices has limited the span of ambient particulate matter monitoring in Sri Lanka to a few cities only. Our main objective is to design and fabricate an affordable device for measuring the concentration of airborne soot particles. By doing so, our goal is to popularize air quality measuring exercises in the country with the view of raising the awareness on ambient air quality.

Studies have revealed that more than 90% of the absorption of solar light in the visible region is by aerosol black carbon (Horvath, 1993). Therefore, measurement of Light Absorption Coefficient of air is a direct way of determining the concentration of black carbon present in the atmosphere (Hansen et al., 1993). In this research, a compact low cost device has been designed and fabricated to measure the optical absorption coefficient of ambient black carbon particles collected on a filter paper.

Materials and methods The experimental setup that is used for the measurements is shown in Figure 1. The lamp, convex lens, filter holder, filter and the light dependant resistor are enclosed in a sealed box made out of chip boards. The inner-side of the container is painted black so that light back scattered from the filter does not reach the monitor or by multiple reflections reaches the filter again. When measuring the light absorption, the filter is placed in the filter holder and the lamp is switched on. It takes

nearly 15 minutes for the lamp to get stabilized and the container to reach thermal equilibrium. The lamp is at the side of the filter where particles are collected and a light dependant resistor is on the other side of the filter. A convex lens is placed between the light source and the filter to concentrate the light path to a small area of the filter. The light that reaches the filter passes through a layer of particles: part is absorbed by the particles, part is scattered and a part is passed through. The fraction that is passed through reaches the filter and is scattered by its pores. The light path is then again concentrated using a convex lens, and the amount of light that reaches the light dependant resistor is sensed, amplified and measured. At present, the out put signal from the device is a resistance value that is proportional to the light absorption coefficient of the particle sample.

Results and discussion Table 1 gives the data collected during the experiment. Column 3 of the table shows the concentration of PM10 (Particulate matter less that 10 µm in size) obtained at several road side locations (given in column 2) using a high volume air sampler (Envirotech APM 460). “US-EPA federal reference method” (US EPA, 1999) was followed in sampling. Each filter paper is subjected to the light source through the device and the final out put resistance is recorded in ohms, which is shown in the last column of Table 1.

In Figure 2, the recorded value of the resistance is plotted against the concentration of PM10. These two variables correlate with each other with a correlation coefficient (R) of 0.8759, which assures that the method tested in this study could lead to the successful development of the measuring device in its next stages. The results obtained using the above set up are subject to the assumption that all the filter papers have unique and uniform characteristics, and that the amount of light absorbed by the filter material is a constant.


206

Table 1. Mass concentration of PM10 and resistance obtained from the experimental set up for different filter samples

No

Air pollution measurement Site

Concentration of PM10 (μg/m3)

Resistance from the experimental set up

( Ω) 1 Blank Filter paper (Reference) 0 4.5 2 In front of Kandy Girl’s High School 171 52.5 3 In front of Art’s theater (Peradeniya) 28 9.6 4 Infront of Kandy Post Office 176 14.6 5 Good’s shed Bus Stand 167 21.9 6 Gannoruwa 13 5.6 7 Idamegama 17 5.4 8 Inside Peradeniya Botanical Gardens 4 5.9 9 In front of Peradeniya Botanical Gardens 113 12.4

10 Near Katugastota Bridge 346 64.0

Lamp Convex

Lens

Convex Lens

Light Dependant

Resistor Amplifier and multi

meter

Filter and filter

holder

Figure 1. Experimental setup

R = 0.8759

0

10

20

30

40

50

60

70

0 100 200 300 400

PM10 concentration (in μg/m3)

Res

ista

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Mea

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d (Ω

)

Figure 2. Resistance measured from the device plotted against the PM10 concentration


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amount of light absorbed by the filter material is a constant.

Conclusions The results obtained so far using the lab scale device for measuring the light absorption coefficient of ambient particulate matter gives a high correlation coefficient (R) of 0.8759 between the mass concentration of PM10 and the resistance reading obtained using the device. Therefore modifications are adopted for further improvement of the device.

At present the light absorption measurements are being repeated with a photo detector in place of the light dependant resistor, since the former has a wider sensitivity range and a longer life than the latter. The sealed box used is also being modified to facilitate online monitoring so that the particles are captured by the filter paper when a mass of air is drawn through the box.

Acknowledgements

University Research Grant No RG/2006/27/E is greatly acknowledged.

References Ernesto, G., Catalan, L., Ormeno, I. and Palma,

G. (2000) Traffic and seasonal dependence of the light absorption coefficient in Santiago de Chile, Applied Optics, 39(27), 4895-4901.

Gundel, L.A., Dod, R.L., Rosen, H. and Novakov, T. (1984) The relationship between optical attenuation and black carbon concentration for ambient and source particles, The Science of the Total Environment, 36, 197-202.

Hansen, A.D.A., Kapustin, V.N., Kopeikin, V.M., Gilletee, D.A. and Budhaine, B.A. (1993) Optical Absorption by aerosol black carbon and dust in a desert region of central asia Atmospheric Environment, 27A(16), 2527-2531.

Horvath, H. (1993) Atmospheric light absorption: A review, Atmos. Environ., 27, 293-317.

US EPA (1999) Compendium of Methods for the Determination of Inorganic Compounds in Ambient Air- Continuous measurement of PM10 suspended particulate matter (SPM) in ambient air, Chapter 10-1.


208

Application of Electro-Coagulation for the Treatment of Wastewater from Vehicle Service Stations

I.R. Samarathunga* and D.G.G.P. Karunaratne


Introduction Vehicle service stations generate considerable amount of wastewater and existing treatment methods in most of these facilities in Sri Lanka are not up to the required standards. Most of the methods employed, such as the use of fat traps, sand filters and charcoal filters, are limited to the physical treatment of wastewater. By physical treatment only free oil and grease are removed but the dispersed oil, which has a smaller particle size than the free oil, is not removed effectively. Therefore, a proper chemical treatment method should be implemented to reduce the oil content in the discharged wastewater from the vehicle service stations.

The intention of this study is to determine a suitable chemical treatment method and to optimise it to treat both free and dissolved oil and grease in the wastewater from vehicle service stations effectively. The chemical treatment methods tested in this study were electro-coagulation using aluminium and mild steel electrodes and the use of alum as a coagulant.


Experiment planning For electro-coagulation, the effect of reaction time, current density and the sedimentation time on oil removal was investigated. The other factors such as pH, the distance between the electrodes, and the conductivity of the mixture were kept constant at the optimum values reported in the literature. Accordingly, for every trial, the initial pH value was kept at 6, the conductivity of the wastewater sample was adjusted using 0.6 g/l of NaCl, and the distance between the plates was kept at 10 mm (Xu and Zhu, 2004). In addition, the contact area of the electrode plates was also kept constant.

Experimental method Wastewater for the study was obtained from a service station, which has a reasonably good treatment facility, and the samples collected were effluents from the treatment plant. In electro-coagulation, the treatment of wastewater was examined by varying the current and the reaction time for each type of anode plate; aluminium and mild steel. Aluminium cathode was used in both cases. In chemical coagulation, effect of alum dosage on removal was studied at different reaction times.

Measurements After a given reaction time, the turbidity was measured in 10 minutes intervals up to a total of 120 minutes of sedimentation time. The oil and grease test was carried out for samples which had been treated for a given reaction time and had been allowed to settle for a time period of 90 minutes.

The oil and the grease content of the wastewater sample were measured using the standard gravimetric method (Eaton and Awwa, 1995) and the Turbidity was measured using the turbidity meter in NTU.

Results and discussion The turbidity and oil removal for different combinations of current density values and reaction times were measured for the three types of treatment methods tested. Figure 1 indicates the variation of turbidity removal with sediment time and reaction time when Al anode was used. Oil removal efficiency for these conditions is shown in Figure 2.

From the results obtained, it is evident that an increase in reaction time and current density will increase the removal of turbidity and oil for both types of anodes. For the chemical coagulation process, the removal of turbidity, oil and grease increased with the alum dosage.


209

Figure 1. Turbidity removal vs sedimentation time for Al anode at different reaction times It should be noted that the wastewater used in this study had already gone through the physical treatment process and most of the oil remaining is dispersed oil, which is difficult to remove. This is the reason for low oil removal in this study.

In this study, the maximum turbidity removal was archived with the use of aluminium anode at the conditions of a current supply of 3 A and 60 minutes of reaction time, while the

maximum oil and grease removal was archived with mild steel anode at a current supply of 4 A and a reaction time of 40 minutes.

A comparison of the three treatment methods is as shown below in Figures 3 and 4. Hence, is not that suitable to use in daily applications.

Figure 3. Maximum turbidity removal in three different treatment methods

Oil removal efficiency

0

5

10

15

20

25

30

35

40

10 20 30 40 50 60

Reaction time /min

Oil

rem

oval

effi

cien

cy/%

Figure 2. Oil and grease removal Vs Reaction time for Al anode

Maximum Turbidity Removal

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

Turbidity Removal trials

Turb

idity

Rem

oval

/%

Al - Anode, 3A, 60min Fe - Anode, 4A, 40min

Alum Dosage - 8 g/l

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100 110 120

Sedimentation time /min

Turb

idity

rem

oval

/%

60min 50min 40min30min 20min 10min

Reaction times


210

Figure 4. Maximum oil removal in three different treatment methods at 90 min sedimentation time

Conclusions Considering both oil removal and turbidity removal, it can be concluded that, for the range of dosage used in the experiment, the Electro coagulation process is more efficient than the use of Alum for the treatment of wastewater discharged from a vehicle service stations.

In electro-coagulation method the oil removal efficiency was higher for mild steel anodes compared to aluminium.

References Eaton, A. D. and Awwa, (1995) Standard

methods for the examination of water and wastewater.

Xu, X. and Zhu, X. (2004) Treatment of refectory oily wastewater, Electro-coagulation process, Chemosphere 56.

Maximum Oil Removal

0.005.00

10.0015.0020.0025.0030.0035.00

1

Oil

rem

oval

%

Al - Anode(4A ,40min) Fe - Anode (4A, 40min)

Alum Dosage 8 g/l


211

Strength and Ductility Evaluation of Rigid-Frames Using Finite Element Analysis

K.A.S. Susantha1* and T. Aoki2 1Department of Engineering Mathematics, Faculty of Engineering, University of Peradeniya

2Department of Civil Engineering, Aichi Institute of Technology, Toyota, Japan

Introduction Improvement of highway network of Sri Lanka includes construction of motorways, flyover crossings, various bridge structures, etc. These structures can have sub-structure components such as cantilever type columns, inverted L-shaped piers, and rigid-frames, which are primarily constructed using concrete. However, steel is also a very useful construction material since it offers a great flexibility in space utilization, has speedy construction time and high earthquake resisting characteristics. In particular, steel rigid-frames supporting highway bridge systems are popular in many countries due to their effectiveness in overcoming space restrictions. Introduction of rigid-frames in large-scale motorway improvement projects in Sri Lanka would be very helpful when densely constructed areas are concerned. Meanwhile, there is a considerable interest among professionals involving infrastructure projects to ensure adequate earthquake resistance in view of many recent earthquake events reported in the region. Therefore, an analytical investigation that involves a large displacement finite element analysis procedure is carried out to examine the performance of rigid-frames subjected to earthquake-induced forces.

Analytical model Finite element analysis method (FEM) is known to be accurate in analyzing steel structures provided that realistic material model and proper elements with optimum element mesh are employed. In this study, numerical model of a steel rigid-frame pier was made using general purpose finite element analysis program Abaqus (Abqus, 2003). The model consisted of a one-story, rigid-frame pier with a beam length of 5.0m, a column height of 5.8m, and a 6600600 ×× mm rectangular cross section that has 12 longitudinal stiffeners (sizes: 50×6 (column), 80×8 (beam flange), 60×8 (beam web)), as shown in Figure 1. More details of the model can be found in Nishikawa et al., (1998).

There are eight diaphragm plates in one column and six in the beam. Yield strength of steel was 298 MPa. The finite element mesh of the model is shown in Figure 2. The model consists of four-nodes doubly curved shell element (S4R) at column bases and adjacent panels of beam column joints, four-node linear beam-column element (B31OSH) at mid segments of columns and the beam, and rigid beam elements (R2D2) at the beam column joints and the interface between shell and beam-column elements. The load bearing capacity beyond the peak load occurs mainly due to the local buckling deformation at column bases and probably at beam-column joints. Thus it is essential to use shell element at those locations in order to capture the effects of the local buckling deformations. The lengths of the segments where the beam-column elements were assigned were decided so that the elements undergo elastic or very little inelastic deformation. Therefore the use of beam-column elements would not lessen the accuracy but increases the computational efficiency. In order to simulate the proper boundary condition at the interface of beam-column and shell elements and column and beam joints rigid beam elements were used. Only a half of the frame was modeled considering the symmetry in loading and the geometry. Mesh size was decided based on a trial and error method. The length between the base and the first diaphragm is divided into 18 segments while subsequent lengths are divided into 6 segments. Each sub-panel between longitudinal stiffeners consists of 4 columns of shell elements. Three columns of elements were assigned in longitudinal stiffeners. The material behavior of shell elements was simulated using the modified two surface plasticity model (2SM) (Shen et al., 1995) externally linked to the Abaqus program. The beam-column elements were simulated using a bilinear elasto-plastic material model available in the program. The 2SM has been extensively checked and found to be very accurate in inelastic cyclic analysis of steel structures. A subroutine has been developed for 2SM and is connected to the ABAQUS through the user defined material option. Since the beam-


212

column elements undergo elastic or very little inelastic deformations the use of bilinear model would not affect the accuracy. When loading procedure is concerned, first the vertical load P given by 0.15 times the yield load of the column was applied at columns top and then the incremental cyclic lateral loads were applied in terms of multiples of yield displacement δy (i.e., ± δy, ± 2δy, etc.) at the top left corner, as indicated in Figure 2. The displacement corresponding to the yield load was taken to be the yield displacement.

Result and discussion

The strength and ductility of the frame can be evaluated using the envelope curve of the lateral load-lateral displacement hysteretic curve shown in Figure 3. It is seen here that the maximum load occurred at displacement level of 2δy and beyond that a gradual decrease in

load carrying capacity was observed. Normally, the strength is given in terms of the ratio of maximum lateral load Hmax to Hy (i.e., Hmax/Hy). The ductility (μ) is given by either the ratio of lateral displacements at Hmax to δy (i.e., μm=δm/δy) or lateral displacement at 0.95Hmax beyond the peak to δy (i.e., μ95= δ95/δy) (Aoki and Susantha 2005). Above two definitions are graphically shown in Figure 4. The values of Hmax/Hy, δm/δy, and δ95/δy of the frame are 1.30, 2.0, and 2.70, respectively.

The failure modes such as local buckling at column bases and in adjacent panes of beam-column connections could be observed from this analysis as shown in Figure 5. The local buckling patterns at the column bases were similar to those normally observed in cantilever type steel columns subjected to cyclic lateral loads.

Figure 1. Rigid-frame model Figure 2. FEM model

Figure 3. Lateral load-lateral displacement curve Figure 4. Ductility indices μm and μ95

-200 -100 0 100 200Disp. (mm)

-1000

-500

0

500

1000

Lat

. L

oad

(kN

)

Displacement, δ

Late

ral L

oad,

H

Hmax0.95Hmax

δm δ95

μm=δm/δyμ95=δ95/δy

Hy

δy


213

Conclusions Large displacement finite element analysis procedure was used to evaluate seismic resisting characteristics of rigid-frame bridge piers. The maximum load was found to be 30 percent higher than the yield load of the frame. The ductility was around 2.7. The decrease in load bearing capacity occurred as a result of local buckling deformation at column bases and beam column connections.

References ABAQUS User’s Manual-version 6.4 (2003)

ABAQUS, Inc., Pawtucket, R. I.

Aoki, T. and Susantha, K.A.S. (2005) Seismic performance of rectangular-shaped steel piers under cyclic loading, Journal of Structural Engineering, ASCE, 131(2), 240-249.

Nishikawa, K., Josen, Y., Takahashi, M., and Takaku, T. (1998) Experimental study on failure and collapse of rigid-frame piers of highway bridges, Proceedings of the 14th US-Japan Bridge Engineering Workshop, PWRI, Pittsburgh.

Shen, C., Mamaghani, I.H.P., Mizuno, E. and Usami, T. (1995) Cyclic behavior of structural steels, Journal of Structural Engineering, ASCE, 121(11), 1165-1172.

Figure 5. Deformed shapes at 7δy


214

Y

XY

Initiation of Thermal Cracks in a Weir

M.M.G.V. Shyamalee*, C.K. Pathirana, H. Abeyruwan and K.R.B. Herath

Department of Civil Engineering, Faculty of Engineering, University of Peradeniya

Introduction The mass concrete weir considered in this study is supported in a trench of solid rock at the bed of a river. This study follows the observation of surface cracks at a few locations in the weir after a few days of casting. Heat of hydration developed in mass concrete is considered to be the main cause for the cracks. A finite element analysis was done on the weir to understand the thermal stresses due to heat of hydration. Based on the stresses obtained in this study, an attempt is made to predict the locations of initiation of cracks using the principles of fracture mechanics.

Two-dimensional plane-stress and plane-strain analyses were carried-out on the weir using SAP2000 (1998) finite element code for thermal loads. A four-node quadrilateral isoparametric element was used for the analysis. These analyses would provide the general thermal stresses developed in the weir due to temperature variation across the cross section of the weir.

Methodology A two-dimensional finite element model was created according to the actual dimensions of a weir, which is currently under construction. The bottom of the weir is considered to be connected to solid rock. Therefore, it was considered as a rigid base and the bottom boundary was fixed against both vertical and horizontal displacements. The grout curtain between the bottom foundation and the weir was assumed to be fully in place and hence uplift thrust was not considered in the analysis (Shyamalee et al., 2007a and 2007b). The weir is to be made from Grade 25 concrete and the Poisson’s ratio of the concrete was taken as 0.2.

Locations of the largest values of major principal stresses due to thermal loads during the initial hydration of the fresh concrete and the major principal stress contours due to thermal loads and self weight are obtained from finite element analyses and are reported herein. These stresses values are then used to predict

the locations of initiation of cracks due to thermal effects.

The finite element mesh used for the analysis is shown in Figure 1. X and Y are horizontal and vertical axes, respectively. Bottom nodes along the X-axis are fixed to prevent both horizontal and vertical displacements. The Z direction is horizontal and along the weir.

Figure 1. Finite element mesh used in the analysis

Figure 2. Temperature contours due to heat of hydration

Concrete is placed at 20 0C and the maximum hydration temperature was measured to be 77 0C at the core of the weir. It was also observed that the hydration temperature at the outer surfaces of the weir was the ambient temperature. Therefore, the hydration temperature was given as temperature contours

0.7 m1

1

2.0 m

0.4 m1.0 m6.1 m

3.4 m

8.1 m

Upstream

Downstream

X

77 0C

27 0C


215

for the purpose of finite element analysis with a maximum temperature of 77 0C at the core and the outer surfaces at the ambient temperature of 27 0C as shown in Figure 2. Since the weir was cast as a series of longitudinal segments, each nearly 5 m long, the stress analyses were done for two extreme cases of plane stress and plane strain to understand the distribution of thermal stresses in the weir.

Results The contours of major principal stress for the case of plane stress analysis are shown in Figure 3.

Figure 3. Contours of major principal stresses in MPa for plane stress analysis

Figure 4. Contours of major principal stresses in MPa for plane strain analysis

It was observed that the largest value of major principal stress occurred at location A on the weir surface as shown in Figure 3. The value of principal stress at location A was 10.1 MPa in the direction of -380 at X-axis. At location B of the inclined surface of the weir, the major principal stress was found to be 9.1 MPa at the direction of -450 to X-axis. On the upstream

face, the highest value of major principal stress was observed as 6.2 MPa at the location C in the direction of 890 to X-axis.

For the plane strain analysis the highest major principal stress occurred at A', shown in Figure 4, and identical to A in the earlier figure. On the inclined surface of the upstream end of the weir, the highest major principal stress was observed at B' again identical to B in the earlier figure. The principal stresses at locations A' and B' were 8.6 MPa in the direction -38o and 7.5 MPa in the direction -45o, respectively. On the upstream face, the highest value of major principal stress was observed as 4.4 MPa at location C', identical location to C in the earlier figure, in the direction of 89o to X-axis.

The major principal stress variations were also studied at locations A, B and C for different core temperatures and are reported in Figures 5 and 6, respectively, for plane stress and plane strain conditions.

Figure 5. Maximum principal stress variations (plane stress) at critical locations

CSign Convention:

Tensile stress - Positive Compressive stress - Negative

A

A′B′

B

C′ 0

2

4

6

8

10

12

14

27 37 47 57 67 77 87

Core Temperature / 0C

Maj

or. P

rin. S

tress

/ M

Pa

Location A

Location B

Location C

-2

0

2

4

6

8

10

12

27 37 47 57 67 77 87

Core Temperature / 0C

Maj

or. P

rin. S

tress

/ M

Pa

Location A

Location B

Location C

Figure 6. Maximum principal stress variations (plane strain) at critical locations


216

Discussion of results and conclusions From the results, the locations, where high principal stresses occured were identified as A, B and C (also identified as A', B' and C’). Since the location A is an intersection point where inclined and horizontal surfaces meet together, a significant amount of reinforcements were provided at this location even without having any knowledge about thermal effects and that might be enough to resist the tensile stresses developed by the hydration heat. Therefore, no cracks may appear near location A during the initial hydration period of the weir.

Locations B and C were also identified as possible critical locations for initiation of cracks and actually there were two surface cracks initiated from those locations and propagated in inward normal directions of the surface during the initial hydration period of the concrete. The values of principal stresses and their directions were not significantly different at locations B and C for both plane stress and strain analyses.

For plane strain condition, the stress intensity factors calculated for 1 mm surface flaws of the concrete at locations B and C are 0.5 MPa m1/2 and 0.3 MPa m1/2 respectively. These values exceed the fracture toughness of concrete (0.2 MPa m1/2) and initiations of cracks due to small surface flaws at these locations are hence justified.

Even though the visible cracks appeared in the concrete surfaces during initial hydration they

will get healed towards the end of the hydration period and with the maturity of concrete.

The results obtained in this study mainly depend on the mesh size used, aspect ratios of elements and the boundary conditions. The results would be slightly different slightly if a finer mesh having better aspect ratios for elements is used or different boundary conditions are used for the analysis.

This analysis has provided a reasonable understanding of the process of initiation of surface cracks and their location in mass concrete during the initial hydration period.

References SAP2000 Non-linear, Version 10.0.1 (1998)

Analysis Reference User’s manuals, Computers and Structures Incorporation (CSI), Berkeley, California, USA.

Shyamalee, M.M.G.V., Pathirana, C.K. and Herath, K.R.B.(2007a) Analysis of a weir for earthquake loading, Proceedings of the International Conference on Mitigation of the Risk of Natural Hazards, March 27-28, University of Peradeniya, Sri Lanka, ISBN 955-589-099-1, 50.

Shyamalee, M.M.G.V., Pathirana, C.K. and Herath, K.R.B. (2007b) Earthquake effect on a weir, A paper submitted to the annual congress of the Sri Lanka Association for Advancement of Science (SLAAS) to be held in December 2007.


217

Secondary (local) stressed area

Primary stressed member

Application of Multiaxial Sequential Law to Estimate Secondary Stress Based-Fatigue Life of Riveted Connections

P.B.R. Dissanayake1* and S.A.S.C. Siriwardane2 1Department of Civil Engineering, Faculty of Engineering, University of Peradeniya

2Department of Civil & Environmental Engineering, Ehime University, Japan

Introduction The secondary stress effect in riveted connections between the primary members of bridges was found to be one of the main reasons for fatigue damage. Present approaches, which are generally used to predict such fatigue damage, are based on a combination of secondary stress histories, effective stress with Miner’s rule and code provided fatigue curve. But under many variable amplitude loading conditions, Miner’s predictions have been found to be unreliable since it does not properly take the loading sequence effect into account. Therefore, a new damage indicator-based sequential law was recently developed to capture the loading sequence effect of variable amplitude loads (Mesmaque et al., 2005). The main objective of this study is to estimate the fatigue life of a riveted connection using this multi-axial sequential law.

A new damage indicator based-sequential law Suppose a structural component is subjected to a stress σi for ni number of cycles at load level i and Ni is the corresponding fatigue life (see Figure 1). The residual life at load level i can be obtained as (Ni−ni). The stress σ(i)eq is the ith level damage stress. Hence, the new damage indicator is given by;

iu

ieqiiD

σσ

σσ

−−

= )( (1)

Where, σu is the intercept of the Wöhler curve with the ordinate at one-quarter of first fatigue cycle. The same damage is then transformed to load level i+1.

1

1)1()(

+

++

−−

=−−

=′

iu

ieqi

iu

ieqiiD

σσ

σσ

σσ

σσ (2)

Where, eqi )1( +′σ is the damage equivalent stress at the level i+1. Thus, RiN )1( +′ can be obtained from Figure 1. 1+iσ is the applied stress at the level i+1 and suppose that it is subjected to

)1( +in number of cycles. Then the

corresponding residual life at load level i+1 is )1()1()1( +++ −′= iRiRi nNN . The cumulative

damage at load level i+1 is defined as,

1

1)1()1(

+

+++ −

−=

iu

ieqiiD

σσ

σσ (3)

The damage indicator is normalized to one (Di=1) at fatigue failure. The effective stress, which characterizes the deformation of the material, is then used to enter a uni-axial S-N curve to determine the damage indicator Di of the sequential law for multiaxial stress state.

Figure 1. Schematic representation of parameters in Wöhler curve

Figure 2. Critical riveted connection

)log(σ

)log(N iN )( iniN − RiN )1( +

′ RiN )1( +

iσeqi )(σ

1)eq(iσ +′1)eq(iσ +uσ


218

Considered connection A riveted connection was selected in a highly stressed member, which was found from the detailed investigation of one of the longest railway bridges in Sri Lanka. The selected connection is shown in Figure 2.

Secondary stress evaluation The critical member without rivets was considered for analysis (Figure 3). The actual air gap restraint conditions were applied to represent the unilateral contact between rivet and plate. The measured uniform tensile stress history of the member was used as the external load. The obtained von Mises stress histories (Figure 4) obtained are converted to stress ranges using the reservoir counting method (Network Rail, 2001).

Figure 4. The von Mises stress histories at critical locations due to heaviest rail traffic

Determination of fatigue curve

The obtained mean S-N curve obtained from the assessment code (Network Rail, 2001) was transformed into a fully known Wöhler curve by using Kohout and Vechet Wöhler curve modeling technique as in Figure 5.

Fatigue life estimation

The new damage indicator based sequential law in multiaxial fatigue was utilized to obtain a more realistic service life for the riveted connection..

Figure 5. The Wöhler curve for wrought iron

Comparisons and discussions The proposed method-based estimated fatigue lives were compared with two other previous approaches. Previous approach 1 (Imam et al., 2007) is based on combination of secondary stress histories, effective stress with Miner’s rule and railway code provided mean fatigue curve. Previous approach 2 (Alampalli and Lund, 2006) is based on combination of primary stress histories, Miner’s rule and code given modified fatigue curve (using the stress concentration factors). The comparisons reveal that results based on the proposed method deviate from previous approaches and it show less residual fatigue lives than other predictions. Finally, the study indicates that the sequential law-based proposed approach gives more realistic residual fatigue life of riveted bridge connections where the detailed stress histories are known.

References Alampalli, S. and Lund, R. (2006) Estimating

fatigue life of bridge components using measured strains, Journal of Bridge Engineering, 11(06), 725-736.

Imam, B.M., Righiniotis, T.D. and Chryssanthopoulos, M.K. (2007) Numerical modeling of riveted railway bridge connections for fatigue evaluation, Engineering Structure, Article in press, doi: 10.1016/j.engstruct.2007.02.011.

Mesmaque, G., Garcia, S., Amrouche, A. and Rubio, G.C. (2005) Sequential law in multiaxial fatigue, a new damage indicator, International Journal of Fatigue, 27(4), 461-467.

Network Rail (2001) RT/CE/C/025, Rail track line code of practice: The structural assessment of under-bridges, Rail track.

Figure 3. FE mesh

-50

0

50

100

150

200

250

0 1 2 3 4 5 6

T i me (s e c )

P rima ry stre ss h isto ry

S tre ss h isto ry wh e n a ll 6 riv e ts a re a c tiv e

S tre ss h isto ry wh e n 5 riv e ts a re a c tiv e




1674.0

120000000

30060

−

+

+

⎥⎦⎤

⎢⎣⎡

=N

Nσ

0

100

200

300

400

500

600

1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+10

Number of cycles N

Stre

ss ra

nge

(MPa

)


219

Reliability Based Resource Allocation in Bridge Maintenance

P.B.R. Dissanayake1* and P.A.K. Karunananda2

1Department of Civil Engineering, Faculty of Engineering, University of Peradeniya

2Department of Civil and Environmental Engineering, Ehime University, Japan

Introduction There is a need for significant investment to repair civil infrastructures worldwide, which are deteriorating under heavy use, severe exposure conditions, and age. Among these, road and railway transportation associated structures play an important role in ground transportation systems and constitute a considerable investment in infrastructure and directly affect the productive capacity of a country (Kong and Frangopol, 2004; Atashi et al., 2007).

In addition to condition evaluation of bridges individually, there is a need to evaluate the condition of bridge paths to guarantee the safety of the total system. This arises from the fact that failure of one bridge in a bridge path affects the total system, especially in case of disasters. Consequently, it is essential to optimise resources expenditure in bridge paths.

Methodology Bridges can fail under different types of failure mode. The critical types of failure mode for a selected bridge can be different from one type of bridge to another. Depending on the type of bridge, failure modes are proposed considering critical failure modes of the bridge concerned as shown in Eq. (1).

iSiRi ZZM −= i = 1, 2…, n (1)

Where, iM is the safety margin for ith mode of failure of the bridge concerned, iRZ is the strength variable and

iSZ is the load variable. The reliability index ( )iβ and failure probability ( )

ifP for ith failure mode can be calculated as the first step. Assuming that all failure modes can be combined into a series system for the bridge concerned, it is possible to calculate the system failure probability ( )FP from simple bounds as shown in equation (2) (Christensen and Baker, 1982; Christensen and Murotsu, 1986).

(2)

Where, FP is the system reliability index of the bridge.

In one route or path, there exist more than one bridge and failure of one bridge makes the road to be ineffective. As this happens, the bridge system located in a route can be considered as a series system. Supposing, there are l number of bridges situated in one path, the path failure probability can be found as below.

(3)

Where, FlP is the path failure probability. For the paths having higher failure probabilities, more resources can be allocated. If path reliability is calculated at different time intervals, preparations can be made on future resource planning.

Numerical example Assume there are three different routes connecting two cities A and B as shown in Figure 1 and bridges are located as shown in the figure. Figure 1. Bridge network between two cities In general, when a bridge is constructed initially, its reliability index is a high and it reduces with time. Allowable reliability indices are around 2 to 3. Considering these, the reliability indices of different bridges given in Table 1 were assumed. ∏ −−≤≤

=

n

i ifFif

n

iPPPMax )1(1

2,1

∏ −−≤≤=

l

i iFFliF

l

iPPPMax )1(1

2,1

D C

B1

B

A

B2

B4

B5 B6 B7

B8

B3


220

Table 1. Assumed failure probabilities of bridges

Bridge System reliability

index

System failure probability

B1 4.94 3.5×10-5 B2 5.35 4.5×10-6

B3 4.87 5.5×10-5

B4 4.81 7.5×10-5

B5 4.81 7.5×10-5

B6 4.80 8.0×10-5

B7 5.03 2.5×10-5

B8 5.25 1.0×10-5

Initially, from the values of system reliability indices of bridges, system failure probabilities can be found as shown in the third column of Table 1 and using those, path failure probabilities can be found as outlined in Table 2.

Table 2. Path failure probabilities

Path Lower bound path

Failure probability

Upper bound path

Failure probability

AEB 8×10-5 19×10-5 ACDB 7.5×10-5 11×10-5 ADB 7.5×10-5 13.5×10-5

Discussion This paper proposes a way to evaluate bridge paths performances using reliability theory. As

shown in the numerical example, different path failure probabilities can be found and using this process, path performance can be evaluated. Depending on the path failure probabilities, resources can be allocated in a comprehensive way.

This is the first publication of the authors regarding the concept of resources expenditure using reliability index. They expect to do more research in this area for greater understanding.

Acknowledgements National Science Foundation of Sri Lanka (NSF/SCH/2005/02 and RG/2002/E/01).

References Atashi, M., Lachemi M. and Kianoush (2007)

Numerical modeling of the behavior of overlaid slab panels for reinforced concrete bridge decks, Journal of Engineering Structures, 29(2), 271-281.

Christensen, P.T. and Baker, J. (1982) Structural reliability theory and its applications, Springer-Verlag, Berlin, Germany.

Christensen, P.T. and Murotsu, J. (1986) Application of structural systems reliability theory, Springer-Verlag, Berlin, Germany.

Kong, J.S. and Frangopol, D.M. (2004) Cost–Reliability interaction in life–cycle cost optimization of deteriorating structures, Journal of. Structural Engineering, 130(11), 1704-1712.


221

Seismic Review Sheet for Evaluation of Earthquake Risk of Bridges

H.M.K.G.G.H.B. Herath, L.G.A. Liyanage, M.G.B.S. Manangoda and P.B.R. Dissanayake*

Department of Civil Engineering, University of Peradeniya, Peradeniya

Introduction Sri Lanka, which is situated away from major plate boundaries, is considered to be in a non-seismic zone. However, there have been many seismic events within Sri Lanka in the recent past, which were small in magnitude and with epicenters far from Sri Lanka. Scientists and geologists believe that formation of a new plate boundary, which divides Indo-Australian plate, is about 400 km away from Sri Lanka and could pose a possible risk of future earthquakes in Sri Lanka.

If an earthquake occurs, the whole transportation system could become crippled when the road network is damaged. It is undisputed that key elements of any road network are bridges. This happened in the earthquake trigged tsunami disaster of 26 December 2004 in Sri Lanka. Considering the above, it is very important to evaluate the potential earthquake risk of existing bridges to withstand potential earthquakes.

It is indispensable to perform condition evaluations of all existing bridges for potential earthquake risk on bridges of any road network. However, it is a time-consuming and costly work to evaluate the condition of each and every bridge in Sri Lankan road network. To overcome this difficulty, vulnerable bridges can be identified easily by visual inspection and then a detailed inspection can be performed based on scoring of visual screening of the bridges of a network.

The objective of this research is to upgrade a Seismic Review Sheet by modifying the Seismic Review Sheet (SRS), prepared by Bandara et al., (2006) and then apply the sheet to existing bridges.

Methodology The improving of the Seismic Review Sheet (SRS) shown in Table 2 was done by modifying SRS prepared by Bandara et al., (2006). It converts the building seismic review sheet by Federal Emergency Management Authority (FEMA, USA) to cater for bridges.

Effects of parameters were adjusted considering their relative importance. In order to improve the weight of the SRS, a simple bridge model was designed. Then the bridge model was redesigned changing some items of SRS such as piers (single pier, or multiple piers) in order to improve the weight and the factor while keeping others as constant in that model bridge. Finally, the weight and the factor were improved by considering the displacement of the bridge model.

Total weight in the SRS is 100 and it was distributed among items depending on their importance when considering seismic force resistance.

The visual screening was done using the SRS for the following six bridges. 1. Gannoruwa bridge 2. Highway bridge at Peradeniya 3. Kuruduwaththa bridge 4. Steel railway bridge at Paradeniya 5. Gampola bridge 6. Akbar bridge

Table 1. Results obtained with SRS for six bridges

Bridge Score out of 100 Gannoruwa bridge 87.3 Highway bridge at Peradeniya

34.7

Kuruduwaththa bridge 54.9 Steel railway bridge at Panideniya

44.3

Gampola bridge 62.3 Akbar bridge 46.5

As shown, in Table 1, lower scores represent a higher risk against possible earthquakes.

In such a case, it is better to analyse such bridges in detail as the displacement criterion becomes important in earthquakes. In this context, the highway bridge at Peradeniya and Akbar bridge in Table 1 were analyzed in detail to find maximum possible displacement.


222

Table 2. Seismic Review Sheet

SEISMIC REVIEW SHEET Bridge Name Bridge No. Evaluator Date Bridge Type : Arc Beam Cantilever Truss Suspension SPAN : SLAB DEPTH : PIER HEIGHT : PIER THICKNESS : SEAT LENGTH : SKEW ANGLE :

No Item Weight Evaluation Content (Factor) Gr. Point Yes (0) Yes (0 ) 1 Historical

Events 11 Grade I (1.0) Grade I (1.0 )

Grade III (0.6) Grade IV (0.4 ) 2 Damage 9 Grade V (0)

High (0) Medium (0.5 ) 3 Importance 9 Low (1.0)

Before 1960 (0.1) 1960 - 2980 (0.1 ) 4 Age 7 1980 - 2000 (0.6) After 2000 (1.0 )

RC Bridge (0.6) Steel (1.0 ) Wood (0.4) Composite (0.8 ) 5 Material 7 Pre-Stressed (0.8)

Beam & Slab (0.8) Void Slab (0.3 ) 6 Deck 3 Solid Slab(0.5)

7 Pier 5 Single Pier (0.5) Multiple Pier (1.0)

Open (0.3) Open (0.5 ) 8 Abutment 3 Special (1.0)

9 Foundation 6 Shallow (0) Deep (1.0) Rubber (1.0) Fixed (1.0) 10 Bearing 3 Expansion (0.7)

Hard l (1.0) Medium (0.5 ) 11 Soil Condition 6 Soft (0)

12 Span Depth Ratio 3 s/d >0.5 (0.3) s/d < 0.5 (0.7)

13 Seat Length 7 N>minimum (1.0) N<minimum (0.0 ) 14 Skew Angle 5 α <250 (1.0) α >250 (0.0 ) 15 Pier Ratio, r 3 r > 1.5 (1.0) 1.0< r > 1.5 (0.5 )

None (1.0) One Direction (0.5) 16 Redundancy 2 Both Direction (0)

30 mm (0) Required (1.0) 17 Expansion Joint 3 30mm<Required (0.5)

Rectangular (0.4) Circular (0.6) 18 R/f 4 Hollow (1.0) No r/f (0)

19 Stirrup and Crosstie 4

Having 1350 (1.0)

Less than 1350 (0.0)

Total Points 100


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Upgrading Upgrade needed?

Yes No

Detailed Analysis

Low

Evaluation Priority W>50 Low 50<W<70 Medium 70<W<100 High

Visual Screening by SRS (Weight)

Maximum displacement of the highway bridge at Peradeniya (middle of span) is 465 mm.

Maximum displacement of the Akbar bridge (middle of span) is 360 mm.

Figure 1. Procedure for seismic risk reduction

Discussion By applying the aforementioned procedure to a seismically less resistant bridge, this can be validated to have a reasonable accuracy.

The total weight indicates vulnerability. If the total score is low, the vulnerability is high and if total score is high the vulnerability is low. To get a marginal score a survey has to be carried out and then detailed analysis should be done for bridges in a particular network.

According to the method used in this research, the most seismic vulnerable bridge is the highway bridge at Peradeniya and it has a score of 34.7 and the Akbar bridge has a score of 46.5. Considering their displacement, it can be said that the Peradeniya bridge has higher vulnerability than the Akbar bridge. The result obtained from the SRS also indicated similar results. Therefore, it can be said that the SRS has enough accuracy. Using this SRS, one can evaluate the condition of potential earthquake risk on existing bridges.

References Bandara A.C.R., Priyadarshana G.S. and

Tennakoon N.C. (2006) Condition evaluation of bridges for potential earthquake risk, Undergraduate Research Report, Department of Civil Engineering, University of Peradeniya, Sri Lanka.


224

Equivalent Electric Network Model for Ionic Polymer Metal Composite Dynamics

B.G.L.T. Samaranayake* and A.M.U.S.K. Alahakoon

Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Peradeniya

Introduction Ionic Polymer Metal Composites have been the focus of many researchers around the world for the past few years. Their inherent light weight, flexibility, repeatability and the tip force have been the major concerns to replace the electro-mechanical actuators in a vast variety of application areas ranging from bio medical engineering to unmanned flying devices. Many studies such as Colozza et al., (2007) have been carried out to develop cost effective fabrication techniques, improve electro-chemo-mechanical characteristics, derive finite element and other modeling techniques, etc. However, very little attentions have been paid on the control of IPMCs. One of the main reasons for this is the absence of a globally acceptable model, whose parameters can directly be calculated from the dimensions and the physical properties of the IPMC.

This paper presents an unprecedented approach to dynamic modeling of IPMCs using standard electric network components to model the transient and steady state voltage and current characteristics. This leads to a global model for IPMCs with fine tunable parameters, which depend on the material properties, the manufacturing process and the physical dimensions of the actuator.

Equivalent electric network model To apply precise control techniques for better performance, it is vital to obtain a dynamic model of the system. By observing the current waveform for an applied voltage on the IPMC, this section proposes a capacitor resistor based passive electric linear network to model the dynamics of IPMCs with no external load torque applied. Further, it is derived in the continuous time domain and a methodology is presented to evaluate the parameters using current and voltage measurements.

Background of the proposed model When a square wave step voltage signal is applied on an IPMC, from a voltage source of finite output impedance, a voltage variation as shown in Figure. 1 (upper) can be observed.

This leads to the conclusion that the voltage across an IPMC can not be changed instantaneously. Further, if the voltage source is disconnected, after being connected for some time, a potential difference retains across the top and bottom surface metallic electrodes of the IPMC. These two properties exactly match with the typical characteristics of a capacitor.

When the current through the IPMC corresponding to the above voltage step is observed, there is a spike caused by the voltage step change and it dies out over time. However, it does not decay to zero as in the case of a pure capacitor. Instead a non-zero current flows as long as the voltage is applied. This observation suggests that there should be a resistor parallel to the capacitor. The suggested model is shown in Figure 2(a). Since an uncharged capacitor behaves as short circuited at the instant of applying the input voltage, the initial current should rise to infinity. However, the current through the IPMC as shown in Figure 1 (lower) is finite at the instant of applying the voltage. Therefore there should be a resistor in series to the circuit suggested in Figure 2(a), through which the capacitor can be charged. Assuming the output resistance of the voltage source is Rout, the suggested passive electric network model consisting of a series resistor R1, parallel resistor R2 and a capacitor C, is shown in Figure 2(b).

Table 1. Table title

Figure 1. The voltage applied on the IPMC (upper) and the corresponding current (lower)


225

Figure 2. Initially suggested passive electric network model for the IPMC actuator. (b) Since the initial current is finite, a series resistor R1 is introduced. The output resistance Rout of the voltage source Vs is also included. The voltage measured across the IPMC is V(t)

Passive electric network model derivation Referring to Figure 2(b), the transfer function from the input voltage V to the total network current I is:

⎟⎠⎞

⎜⎝⎛

⎟⎠⎞⎜

⎝⎛ ++

⎟⎠⎞⎜

⎝⎛ +

=

CRRRRsR

CRs

sVsI

21

211

2

1

)()(

(1)

where ‘s’ is the Laplace operator. This can also be presented as

( )( )

( )( )sAsB

asbsK

sVsI

=++

=)()( (2)

where CRRRRa

CRb

RK

21

21

21

,1,1 +===

For a step voltage input, it becomes (3)

In the discrete time domain, with the z-transform operator and h being the sampling period, it becomes

( )( )

( )( )ah

ah

ah ezKbe

ezzK

zVzI

−

−

− −−

+−

−=

11)()( (4)

which can be simplified as ( )

( )dzczK

zVzI

−−

=)()( (5)

where ahah edeac −− =−−= ,1)1( .

Introducing the pulse transfer operator q, it becomes

( ) ( ) ( ) ( )11 −−+−= kcKVkKVkdIkI (6)

This parametric estimation method works well for noise free measurements, which is hard to achieve in practice. Therefore the measurement noise component has to be incorporated in the model. Different parametric system identification models such as Auto Regressive with Extra Input (ARX), Auto Regressive Moving Average with Extra Input (ARMAX) and Box and Jenkin (BJ), which can handle measurement noise are available as derived in Ljung et al., (1999) With the results of the preliminary identification experiments, the BJ model structure, whose block diagram is shown in Figure 3, is used here for the model verification as that has the capability of estimating independent dynamical models between input-output and noise-output.

The strategy used in this paper is to obtain a basic input output model for voltage vs. current dynamics using non-parametric identification methods and verify its validity using parametric identification experiments.

Figure 3. BJ model structure to incorporate measurement noise in the parameter estimation. More accurate noise models may be obtained by suitably selecting the orders of C(s) and D(s). A(s) and B(s) are same as in equation (2)

Results and discussion The model verification is done using both parametric and non-parametric approaches.

Non-parametric identification Referring to step response of IPMC shown in Figure 1, K, b and a of the transfer function model described in equation (2) were estimated using initial value, final value and the time constant of the step response of current. The values are given in Table 1. Figure 4 shows the applied step, measured current and simulated current using the above model.

R1

R2

C

Rout

V(t)Vs

I(t)

C

R

(a) (b)

V(s) ( )( )sAsB

( )( )sDsC

e(s)

I(s)Σ

( ) ( )assKb

asK

)s(V)s(I

++

+=


226

Parametric identification A BJ model was fitted to a recorded voltage and current data set. The input voltage was varied as a pulse sequence of random amplitude and duration. The strategy used in trying to fit the BJ model was to keep the voltage vs. current dynamics fixed according to equation (6) and fine tune noise model to achieve the best fit. The Figure 5 shows the step sequence applied and the corresponding current variation and simulated BJ model and non parametric model outputs for comparison.

As can be seen in Figure 4, most of the time, the non-parametric model output closely follows the basic shape of the experimental output. But the model does not take into account the measurement noise, which is why matching in Figure 4 (d) is poor.

The Figure 5 compares the models obtained by BJ method and non-parametric method with the experimental data, for the series of pulse input voltages. At A, C, and F, where the current rise is shape corresponding to high frequency excitations in the frequency domain, the non-parametric model output is more closer to the actual output. But when the changes are slower in a place like B, the BJ model is better as it incorporates a high order noise model.

Figure 4. Verification of the identified non-parametric model

Figure 5. Comparison (lower) of BJ model and Non-Parametric model with the experimentally obtained output data corresponding to the input voltage pulse sequence (upper)

However, especially from D to E and some other places in the figure, none of the models can match the actual output. This is believed to be due to un-modeled non-linearities.

Table 1. Model parameters of the non-parametric identification

Estimated Parameter

Value

K 0.01168 b 0.0915 a 5.0813

Conclusions and future work An equivalent electric network based dynamic model for IPMCs has been introduced derived and verified experimentally. It will be improved in the future to incorporate the un-modeled non-linearities.

References Colozza, A. (2007) Fly like a bird – Flapping

wings could revolutionize aircraft design IEEE Spectrum, 32–37.

Ljung, L. (1999) System Identification: Theory for User. 2nd Ed., Prentice Hall.


227

Implementation of an Electronic Tuner in J2ME using Fast Fourier Transform

I. Herath and R.G. Ragel*

Department of Computer Engineering, Faculty of Engineering, University of Peradeniya Introduction An electronic tuner is a device used by musicians to tune instruments. There, a musician plays a note and the display of the tuner tells the musician how much the played note has deviated from the desired note in terms of frequency. Most of these devices, such as KORG Chromatic Tuner CA-30, are standalone equipments which are solely used to tune musical instruments. It would be advantageous if this functionality could be integrated into existing electronic appliances like mobile phones as these devices are equipped with all the necessary hardware components to be used as an electronic tuner. In addition, mobile software applications are becoming increasingly popular and authors of this paper uses this opportunity to develop a tuner application to be deployed in mobile phones.

Section two of this paper focuses on related researches on this area and section three describes the methodology used during the development process. Section four shows the results obtained and section five discusses the issues related to development. Finally, section six concludes the paper.

Related work In the first part of this section we will brief two academic researches and in the latter part we will focus on few similar industrial applications. Zaykovskiy and Schmitt (2007) presented front end implementation of speech recognition systems for mobile devices. The signal analysis of these systems is being carried out at the server side where the mobile client does not interfere with signal processing. The shortcoming of this sort of application is the communication overhead between the client and the server. The Java signal analysis application by Clausen et al. (1998) can only be deployed on desktop computers and any other similar or advanced electronic appliances due to the functions used in this particular program.

There are quite a number of mobile applications such as, Guitar Tuner (Kohn, 1997-2007), Tiny Tuner (GetJar.com, 2004-2007), and Chromatic Guitar Tuner (4pockets.com) are available. The Guitar Tuner and Tiny Tuner are simple applications which are only capable of playing a note so that musicians can hear the note and adjust their instruments. However Chromatic Guitar Tuner is a sophisticated application which is capable of analyzing the frequencies and estimating the closest notes. The limitation of this application is that it can only be deployed on high end mobile devices such as Pocket PCs.

Therefore the aim of this project is to develop a mobile application which could be deployed in most of mobile phones. It was a challenging task to implement frequency analysis in low end mobile devices such as Java enabled mobile phones due to their limited functionality. The authors of this paper have succeeded in this by finding a mechanism to implement Fast Fourier Transform (FFT) in Java 2 Micro Edition (J2ME).

Development and implementation The major part of the product is the frequency calculation. The FFT has to be applied to obtain the frequency of the sound wave from which the notes are identified. In order to perform FFT the sound wave needed to be sampled. But the chosen platform, J2ME, does not accompany an Application Programming Interface (API) to deal with sampling the sound. Even though this limitation exists, J2ME was chosen as the development platform due to the higher number of mobile phone models supported by this platform. Then the authors used the only available option, which is to sample the sound wave within the application. The sound wave is sampled and stored as a wave file, which comprises of header (chunk descriptor), “fmt” sub chunk and “data” sub chunk as shown in Figure 1. As depicted in Figure 1, the “fmt” chunk has eight fields which are represented in little endian format except the field chunk ID. The fields which are important from this chunk for the


228

FFT are SampleRate and BitsPerSample. The value represented in BitsPerSample field is being used in deciding the number of bytes to read from data chunk per reading. The value in the sample rate field is being used in calculating the frequency. When the

frequencies are known, it is mapped into the closest notes and displayed to the user. The first phase of our application samples the sound wave by recoding it as an audio clip in wave file format as shown in Figure 1.

Figure 1. The WAVE File Format (taken from (Wilson, 2003))

Figure 2. Algorithm for Obtaining the Frequency

Main: While there is data in data chunk

Call Subroutine1 with 256 samples End while

For (i = 0 to 256) FindMax (|totalCos[i] + totalCos[i]|) location = i End Frequency = SampleRate * location / (2*255) End Main Subroutine1: Input data[] For (i=0 to 256) For (j=0 to 256) X = (-2 * π * i * j ) / 256 cosPart [i] = cosPart [i] + data [j] * Cos (X) sinPart [i] = sinPart [i] + data [j] * Sin (X) End For totalCos [i] = totalCos [i] + cosPart [i] totalSin [i] = totalSin [i] + sinPart [i] End For End Subroutine1


229

The second phase of our application analyses the audio clip in wave file format from where the information is extracted. The values SampleRate and BitsPerSample are read from “fmt” chunk and are stored as application variables. As in Figure 1, the data chunk comprises of a chunk ID (Subchunk2ID), chunk size (Subchunk2Size) and data. The value chunk size is being used to determine the size of the data to be read. Then 256 samples are being read to an array called data which is then being processed by Subroutine1 in the algorithm shown in Figure 2. This process is being carried out until there are no samples to be read. Then as shown in Figure 2, amplitude of the total cos and sin values are being calculated by the FindMax method and the location of the highest amplitude, i.e. between 1 and 255, is determined. Then the frequency is being calculated as shown in the algorithm.

Results The playTone()function (an inbuilt function of the API) in the Manager class is being used to play the notes A, B, C, D, E, F, G and sound is captured via the microphone. The captured data are then being sent to our application to get the frequency of the played notes. Following results were obtained.

Discussion Our application uses cos and sin functions from the Math library. Therefore this application can only be deployed on mobile phones with Connected Limited Device Configuration (CLDC) 1.1 (SunMicrosystems, 2006), where the cos and sin functions are implemented in the Math library. This limits the usability of our application as these functions are not implemented in the Math library of CLDC 1.0 (SunMicrosystems, CLDC Library API Specification 1.0, 2006). Therefore it is necessary to take appropriate measurements to make our application run on CLDC 1.0. The FFT processing time is comparably high due to the floating point arithmetic used during the process. This reduces the performance of the application. Further research and development is required to overcome these issues.

Conclusions This paper presents the mechanism behind the implementation of FFT in J2ME for an electronic tuner application and to the best of our knowledge this is the first time such an effort has succeeded (SunMicrosystems, develop a Musical Tuner, 1994 - 2006).

References 4pockets.com. (n.d.). 4pockets.com. Retrieved

07 30, 2007, from PocketPC Applications: Chromatic Guitar Tuner: http://www.4pockets.com/product_info.php?p=39

Clausen, A., Spanias, A., Xavier, A. and Tampi, M. (1998) A Java signal analysis tool for signal processing experiments, Proceedings of the 1998 IEEE International Conference on Acoustics, Speech and Signal Processing. Seattle, 1998. 1849-1852.

GetJar.com. (2004-2007) Tiny Tuner / free download. Retrieved 07 30, 2007, from Free Java, Symbian, Palm and Pocket PC Software: http://www.getjar.com/products/5314/TinyTuner

Kohn, M. (1997-2007) Guitar Tuner. Retrieved 07 30, 2007, from Michael Kohn: http://www.mikekohn.net/j2me/guitartuner.php

SunMicrosystems (2006) CLDC Library API Specification 1.0. Retrieved 07 30, 2007, from Java Technology: http://java.sun.com/javame/reference/apis/jsr030/

SunMicrosystems (1994 - 2006) Develop a Musical Tuner. Retrieved 07 30, 2007, from Developer Forums Java Technology Forums:http://forum.java.sun.com/thread.jspa?forumID=76&threadID=613127

SunMicrosystems. (2006) Overview (CLDC 1.1). Retrieved 07 30, 2007, from Java Technology: http://java.sun.com/javame/reference/apis/jsr139/

Wilson, S. (2003, 01 20) WAVE PCM soundfile format. Retrieved 07 30, 2007, from Center for Computer Research in Music and Acoustics:http://ccrma.stanford.edu/courses/422/projects/WaveFormat.

Zaykovskiy, D., and Schmitt, A. (2007) Java (J2ME) Front-End for distributed speech recognition, 21st International Conference on Advanced Information, Washington 2007. 353-357.

Table 1. Frequencies obtained for notes played with Mobile Media API

Note A B C D E F GFrequency

(Hz) 220

235

266

298

329

360

392


230

Full Instruction Encoding for Heterogeneous Multi Pipeline Application Specific Instruction-Set Processors

S. Radhakrishnan* and R.G. Ragel

Department of Computer Engineering, Faculty of Engineering, University of Peradeniya

Introduction Embedded systems are becoming ubiquitous, cheaper, powerful, and increasingly ever present in people's life. Since embedded systems usually execute a single application or a class of applications, customization can be applied to optimize for performance, cost, power etc. One popular design platform for embedded systems is the Application Specific Instruction-set Processor (ASIP), which allows such customizability without overly hindering design flexibility. Numerous tools and design systems such as ASIP-meister (PEAS Team, 2002) and Xtensa have been developed for rapid ASIP generation.

Usually ASIPs contain a single execution pipeline. Recently however, there has been trend towards having multiple pipelines. For the first time, in (Radhakrishnan et al., 2005), a design framework was proposed for ASIPs with varying number of pipelines. Given an application specified in C, the design system generates a processor with a number of heterogeneous pipelines specifically suitable to that application. Each pipeline is customized, with a differing instruction set and the instructions are executed in parallel in all pipelines.

In the framework described in (Radhakrishnan et al., 2005), the instruction widths for each pipeline are identical. Later, this work was extended with the aim of reducing processor and code size for such a design by systematically customizing the instruction encoding with differing instruction width for each pipeline, without affecting the performance of the processor. The instruction set for each pipeline is different. Therefore, instead of using identical instruction widths for instruction encoding, each pipeline can have its own encoding scheme with differing instruction width; thus, high density code can be achieved, saving instruction memory.

As an initial attempt to the extension, in (Radhakrishnan et al., 2006) the authors have implemented the customization of instruction encoding and forwarding path for a single

pipeline (which was the third pipeline in a three pipeline design) and have analyzed the benefits of such an approach. The decision to customize the encoding of only the third pipeline was made based on: (1) the observation that it had a smaller subset of instructions compared to the first and the second pipelines and this subset does not require the same instruction width as the first two pipelines do; (2) a limitation on the width of the processors (instruction width could only be a multiplication of eight bits) which could be developed in the tool (ASIP-meister) that was used to generate each pipeline.

In this paper the authors have extended the customization of encoding for all three pipelines. This is achieved by customizing ASIP-meister to generate processors with any instruction width. The authors were able to prove that the customization of all pipelines even with a considerably larger subset of the instructions could yield a saving in overheads. Even though the saving of the number of bits in each pipeline may not be very significant in some of the cases, there is a reduction in area, leakage power and clock cycle of every design considered. This is the first known attempt to perform this reduction in the area of heterogeneous multi-pipeline system through customizing the encoding of all the pipelines.

Design overview The design flow of our target multi-pipeline ASIP framework is as follows: it starts with an application written in C, which is compiled into a single-pipeline assembly code. The single pipeline code is then scheduled into a number of parallel pipelines, from which the instruction set for each individual pipeline is deduced. Next, ASIP-meister, a single-pipeline ASIP design tool, is used to design each single pipeline. All these pipelines are then integrated into a multi-pipeline processor containing a multi-issue structure where the register file is shared by all pipelines. Each pipeline performs its own program sequence and has a separate control unit that controls the operation of the related functional units on that pipeline. This design process is repeated with different


231

number of pipelines until a design that meets the given design criteria is obtained.

Instruction encoding Instruction encoding is the act of using binary bits with certain format to represent instructions. The format of the instructions can be generally divided into two parts: one, operation field or the operation code (op-code), for encoding operation; and the other, multiple operand fields for encoding operands. Our encoding approach uses a fixed instruction width for each individual pipeline, with the width varying from one pipe to another. The encoding starts with the existing instruction sequence produced by the scheduling algorithm. Encoding for each pipe is carried out separately. The instructions in a sequence are grouped based on the type of the instructions. The pattern of operand values is analyzed and operands are encoded with minimal possible number of bits. Based on the operand encoding, the operations of the whole instruction set used by the application program is then encoded. Details for both encoding tasks are given below.

Operand encoding In the instruction set architecture (ISA) used in our design, the operands can generally be classified into two types: registers and immediate values. The encoding strategy is demonstrated in the following with register operands (or registers for simplicity). Conventionally, the size of a register field (or operand field), is determined by the size of the register file. However, with a given program sequence, a certain type of instructions may not use all of those registers. Therefore, the field size can be reduced. Rather than randomly assigning code-words to each of the registers, we used an encoding approach such that the decoding will be simpler, thus reducing hardware complexity, and hence improving performance, area and power. We call this technique reduced-bit efficient encoding or REE. Table 1 compares a typical full bit encoding (FBE) against REE for a given set of register usage.

Table 1. FBE Vs. REE Registers R2 R4 R13 R11

FBE (b3b2b1b0) 0010 0100 1101 1011 REE (c1c0) 10 00 01 11

Row 3 in Table 1 gives an example of such an encoding. Given a register array for a register operand field, we determine the encoding values by using REE algorithm. The full REE algorithm is omitted from this presentation for brevity. Applying this algorithm to each of the operand fields, we can obtain encoding for all operand fields in an instruction type with a minimal number of bits.

Operation encoding We group the instructions according to the number of bits needed for the operand fields. When the instruction type is unique no bits are used for operand fields. The operation field encoding is summarized in Algorithm 1. For each instruction type, the instruction operation encoding progresses from inner most level to the outmost level; and the code size grows accordingly.

Algorithm 1. Operation Encoding

Results and discussion We designed ASIPs for two applications from Mibench embedded systems benchmark suite. The designs were later synthesized using Synopsys Design Compiler based on the Taiwan Semiconductor Manufacturing Company’s (TSMC) 90nm core library, and simulated with the Modelsim simulator. Figure 1 depicts the area, clock cycle and leakage power comparisons of the non-customized (typically encoded) and customized (fully encoded) designs. The average savings are 26.9% on area, 27.8% on leakage power and at the same time there is a reduction in clock cycle by 1.4%. In addition, the average instruction memory size saving is about 69%.

For instruction encoding, many approaches have been proposed. In (Lee et al., 2002), authors presented a technique that encodes all


232

instructions, required by an ASIP, with a given instruction size. A hierarchical instruction encoding for VLIW-based architecture application is presented in (Liu, 2005). These approaches are not tailored to our target processors proposed in (Radhakrishnan et al., 2005). The techniques presented in this paper exploit the unique architectural feature of our target heterogeneous multi-pipeline ASIP.

Conclusions We presented techniques to fully customize instruction encoding for a multiple pipe processor. This approach best trades off the simplicity of fixed size encoding approaches and high density of varied size encoding techniques. The encoding is customized, with each pipeline having its own fixed instruction width and the instruction width varying from one pipe to another, and hence achieving a better trade-off between the design simplicity of the fixed-width encoding and code reduction efficiency of the varied-width encoding. Due to the resource and time limitation only few applications were implemented for the current work. Many versatile applications will be

implemented in the future work for customization of processor.

References Lee, J.S., Choi, K. and Dutt, N. (2002)

Efficient instruction encoding for automatic instruction-set design of configurable ASIPs, ICCAD, 649-654.

Liu, C.H. (2005) Hierarchical instruction encoding for VLIW digital signal processors, ISCAS, 3053-3056.

PEAS Team. (2002) ASIP Meister Toolset. Retrieved 4 2007, from ASIP Meister: http://vlsilab.ics.es.osaka-u.ac.jp/dac2003/.

Radhakrishnan, S., Hui, G. and Parameswaran, S. (2005) n-pipe: Application specific heterogeneous multi-pipeline processor design, Workshop for Application Specific Processors.

Radhakrishnan, S., Hui, G., Parameswaran, S. and Aleksandar, I. (2006) Application specific forwarding network and instruction encoding for multipipe ASIPs, CODES_ISSS: 06, Proceedings of the fourth International Conference on CODES.

Figure 1. Savings due to full customization of encoding


233

An Algorithm for Automatic Playlist Generation in Radio Stations

I.M.K. Kahanda* and U.G. Kanewela

Department of Computer Engineering, Faculty of Engineering, University of Peradeniya Introduction In a typical radio station, DJs play songs using pre-generated playlists. A playlist is a set of music titles which should be played in a given order. Composing high quality playlists for radio stations is very demanding because of the large number of songs available for selection. Therefore the person responsible for composing playlists have to either memorize or listen to the excerpts of the songs in order to choose the right song for the right situation.

All the radio stations in Sri Lanka build their playlists manually. In today’s competitive world, even though maintaining a high standard largely defines the popularity of the station, the above situation makes it difficult for a human to achieve this consistently. This is the motivation for this research which examined the feasibility of using a computer to generate music playlists for radio stations using a newly developed Automatic Playlist Generation (APG) algorithm.

Related work APG, which is formally defined by Pauws et al., (2006) has enjoyed lots of research recently and the researchers have come up with many different approaches depending on different applications, such as similarity based techniques for Personal music players to Constraint Satisfaction Programming (CSP) approach for Electronic Music Distribution (EMD) systems. Similarity based techniques are specially used for recommender systems, in which the listener selects one or more of her favorite songs to be used as seed songs and the generator will pick the rest of the songs one by one for the unordered playlist. Collaborative filtering (French and Hauver, 2001; Pestoni et al., 2001), timbre similarity measures (Logan and Salomon, 2001; Aucouturier and Pachet, 2002) and machine learning using existing playlists (Platt et al., 2002) are the popular similarity based techniques. The major advantage of using these techniques is that their sensitivity in capturing the changes in the choices of a single listener.

In CSP approach, instead of selecting individual music titles, one by one, like above, the idea is to produce a collection of music titles, in an order, restricted to a set of global constraints (Pachet et al., 1999). One of the better CSP approaches to APG, with regard to scalability is proposed by Aucouturier and Prachet (Pachet, 2002), which starts by having a random set of songs from the whole set, and iteratively tries to improve the playlist by making small changes to it, using adaptive search (an adaptation of the local search) algorithm (Codognet and Diaz, 2001).

Both these approaches so far have looked at APG for playlist generation mainly for a set of very few listeners or a large set of listeners which can provide immediate feedback. This paper, for the first time, presents an APG technique for radio stations (a large global set of listeners from which continuous immediate feedback cannot be obtained), PlayGen, which is a hybrid of the aforementioned techniques and enjoys the benefits of both the schemes.

Methodology The APG algorithm presented in this paper, PlayGen, uses the algorithm presented in (Prachet, 2002) as a starting point due to its scalability. The main idea of that the algorithm presented is that the qualities/characteristics which a playlist should posses are described as constraints.

Problem statement The playlist generation problem is defined as follows in (Prachet, 2002). A playlist S is a sequence of variables v1, v2…, vn whose values xi can be taken from a catalogue of music titles D. The problem is to assign values to variables, so that the resulting sequence satisfies constraints c1, c2,…,cm.

Constraints Constraints are seen as simple cost functions. The cost represents how ‘bad’ the constraint is satisfied, for the given assignment of variables. Constraints may hold on attributes of music


234

titles and these are typically metadata of songs. Therefore, a playlist will have a total cost associated with it. The algorithm starts with a certain initial playlist (having a certain total cost) and iteratively refines the solution until a playlist satisfying all the given constraints (having a total cost less than a given threshold) is found. Authors have developed the following three compulsory constraints for radio stations along with several other optional ones.

• C-ALL-DIFFERENT: Two songs of the same album/artist should not be included.

• C-DISTRIBUTION: Genre (e.g. pop), type of artist (e.g. female), release year and tempos (in beats per minute) of two consecutive songs should be different.

• C-VARIETY: Number of different genres of songs should exceed a certain threshold.

For example, the cost associated with C-VARIETY is quantified as follows.

Cost(C-VARIETY):

Return the length of the playlist – number of genres of music titles divided by length of the playlist

PlayGen algorithm PlayGen possesses two major features which are not found in the APG algorithm presented in (Pachet, 2002). First, as shown in Figure 1, the PlayGen algorithm searches only through a small subset of songs termed request neighbor set (RNS), as opposed to the whole set D. RNS is the set of similar songs to the recent listener song requests, which is generated by the nearest neighbour algorithm utilizing the metadata and calculated attributes of music titles, and specially helps when the collection is very large like in a typical radio station, since it narrows the search space effectively. Formal definition of RNS is given below. RNS = N songs with min(TotalDistance(xi,xr)) Where, xr=requested song and xi=all other songs. TotalDistance(x1,x2)=∑distance(a1j,a2j) Where a1j and a2j are the jth attribute of x1 and x2 respectively.

Secondly the algorithm introduces a new attribute of a song, playability, which derives the suitability of a song to be played at the

moment of time considered. Playability function P is defined as follows. P=P(release year, number. of times requested/ recommended, last time played, time of the day).

Further, the algorithm addresses a set of global constraints that would cover various requirements of any radio station as detailed under constraints. Therefore, this is the first time that these two (CSP and similarity based) techniques are combined to develop a hybrid APG algorithm for radio stations.

Figure 1. PlayGen algorithm

Experimental results

Figure 2. Example playlist

The evaluation method of the algorithm was to provide a collection of playlists generated by PlayGen to two different sets of testers, to be rated in a scale of 5 where score of 1 means “completely unsuitable to be played on radio” and a score of 5 means “perfectly suitable to be played on radio”. Firstly, a professional playlist composer (E) at a radio broadcasting corporation rated them by estimating the suitability of them to be played on their radio

(0) bonnie & clide - beyonze - rap - 2002 (1) give it to me - nelly furtado - rock - 2007 (2) you all dat - baha men - world - 2000 (3) all rise - blue - rock - 2001 (4) smack that - eminem - rap -2006 (5) feel good inc. - gorillaz - rock -2005 (6) with oive - hilary duff - pop - 2007 (7) because of you - ne-yo - rnb - 2007 (8) coco jumbo – mr president - pop - 2000 (9) real girl - mutya buena - rock - 2007

Let SS ≡ playlist, PP ≡ set of playable songs and dj ∈ D

Assign random songs from PP∩∩RRNNSS to SS

Until cost(SS) is less than threshold

For each vi

Calculate cost vi

Find vw whose cost is the worst

For each song dj ∉ SS and dj ∈ PP

vw dj

Calculate cost(vw)

Locate dL with the lowest- cost(vw dj)

vw dL

Find cost(SS)


235

station. Secondly, a set of frequent radio listeners (L) of the above station rated them considering their own satisfaction derived out of listening to them, relating to qualities like variety etc. In a set of five playlists, the playlists 1-4 were generated using all three compulsory constraints (of which playlist 3 is depicted in Figure 2) while playlist 5 was randomly generated using only C-ALL-DIFFRENT constraint. Figure 3 depicts the playlist ratings from the test. All five playlists were generated from a database containing song attributes of 200 music titles. Most of the attributes were metadata of songs like title, artist, album, and tempo, which were extracted from allmusic.com and id3v2 tags of the songs.

Discussion

Ratings for Playlists

0.00

1.00

2.00

3.00

4.00

5.00

E L E L E L E L E L

Paylist1 Paylist2 Paylist3 Paylist4 Paylist5

Ave

rage

ratin

g

Figure 3. PlayGen ratings

Figure 2 depicts a typical playlist generated by PlayGen. All three compulsory constraints of this playlist are satisfied 100%.The threshold value used was zero and PlayGen took only 1 second in a typical personal computer (PC) to produce the above result. As evident from Figure 3, all playlists (except playlist5, which was randomly generated) have received very good average ratings (higher than 4.3 out of 5) from both E and L, which concludes that PlayGen is capable of generating quality playlists that significantly satisfies the radio station requirements and listener preferences at the same time, even with just three carefully developed constraints.

Conclusions In this paper the authors considered the automatic playlist generation problem. For the first time, two most popular methods, namely

constraint satisfaction approach and the similarity based techniques, of playlist generation, are combined to develop an automatic playlist generator, which would suit radio stations. The developers were able to test and prove that it is feasible to generate quality music playlists using a computer.

References Aucouturier, J.J. and Pachet, F. (2002) Finding

songs that sound the same, Proceedings of IEEE Benelux Workshop on Model based Processing and Coding of Audio, University of Leuven, Belgium.

Codognet, P. and Diaz, D. (2001) Yet another local search method for constraint solving, Proceedings of the AAAI Fall 2001 Symposium, Cape Cod, MA.

French, J.C. and Hauver, D.B. (2001) Flycasting: On the fly broadcasting, Proceedings of International Conference on Web Delivering of Music (WedelMusic), Firenze, Italy.

Logan, B. and Salomon, A. (2001) A music similarity function based on signal analysis, Proceedings of IEEE International Conference on Multimedia and Expo (ICME), Tokyo, Japan.

Pachet, F., Roy, P. and Cazaly, D. (1999) A Combinatorial approach to content-based music Selection, Proceedings of IEEE Multimedia Computing and Systems International Conference, Firenze, Italy.

Pachet, F. (2002) Scaling up music playlist generation, Proceedings of IEEE ICME, Swiss Federal Institute of Technology, EPFL, Lausanne, Switzerland.

Pauws, S., Verhaegh, W. and Vossen, M. (2006) Fast generation of optimal music playlists using local search, Proceedings of International Conference on Music Information Retrieval ( ISMIR), Victoria, Canada.

Pestoni, F., Wolf, J., Habib, A. and Mueller, A. (2001) Karc: Radio research, Proceedings of International Conference on Web Delivering of Music (WedelMusic), Firenze, Italy.

Platt, J.C., Burges, C.J.C., Swenson, S., Weare, C. and Zheng, A. (2002) Learning a Gaussian Process Prior for automatically generating music playlists, Proceedings of Neural Information Processing Systems (NIPS), Vancouver, Canada.


236

User Dependant Speech Based Lip Synchronization

S.M.I. Wickrama1 and J.V. Wijayakulasuooriya2* 1Computing Centre, 2Department of Electrical and Electronic Engineering, Faculty of Engineering,

University of Peradeniya Introduction User dependant speech based lip synchronization is an area that is being researched thoroughly. Combination of the auditory and visual speech recognition is more accurate than only auditory or only visual. Consequently, there has been a large amount of research on incorporating bimodality of a speech into the human-computer interaction interfaces. A speech-driven face animation is one of the research topics in this area, since using natural voice for the animation of synthetic faces remains a challenging area of research in computer animation.

Since the FAPs (Facial Animation Parameters) are required to animate faces of different sizes and proportions, the FAP values are defined in face animation parameter units (FAPU). The mouth is one of the most difficult face features to analyze and track. It has a very versatile shape and almost every muscle of the lower face drives its motion, unlike some areas of the face such as hair line or eyebrows which become mobile only when the user uses certain tones and expressions.

The aim of this research is to develop a speech based lip synchronization technique which operates in real time. The final system should be capable of analyzing a speech signal and re-producing the coordinates of the critical points of the lip. The first part of the research was dedicated to investigating models for the automatic lip synchronization by speech signal analysis and to finding a method which is suitable for recording speech and facial movements with the minimum of equipment.

The research dealt with a method by which the key points (critical points) of the lip could be read as coordinates and stored in a suitable format and also a method by which to process speech signals, so it can be fed into a neural network for quick results and easy training.

It is hoped that by further developing this such a method could be used to in the animation industry and for web communication, such as webcasting and user friendly avatars.

Methodology The first step in this research was to find a suitable recording method for the lip movements and corresponding sound capture. For this, several methods were tried out to see which was the most appropriate for the required project. The recording was done using a Canon XL 1 digital video camcorder with 7.2 V DC power supply. The recordings have a frame rate of 24 frames per second (fps) and a 320x240 resolution. The first recording was in Moving Picture Experts Group (MPEG) format but it was later discovered that Audio Video Interleave (avi) was the better format for picture frame / sound editing.

Most of the avi manipulation and specific frame extraction was done in Adobe Premiere. The coordinates of the key points marked on the lip were obtained using computer graphic methods of a Matlab program. For finer co-ordinate manipulations and storing of data in a more accessible form for those who do not have Matlab (Ver 7.0), Microsoft Excel spread sheets were used. The wave files, in wave and avi format were also processed using Matlab, Adobe Premiere and Goldwave. The neural networks were constructed using Matlab and the output files were also implemented in Matlab graphics (which uses OpenGL which is C based.).

Data collection and pre-processing The work initially started aiming to develop a system that was capable of simulating a 3D face movement with real time user independent speech. However, the work was limited to 2D face movement capture and lip synchronization for user dependant speech signals due to difficulties that arose during the project. These difficulties included extracting key coordinates from the recording, different levels of frame clarity, the lack of proper lighting equipment for the recordings, etc.

The research mainly concentrated on capturing mouth / lip movements and corresponding sounds. It also dealt with some attempts at


237

capturing facial movements using limited equipment and some techniques in sound processing which can be used for phoneme recognition.

Several methods were tried out to find a suitable arrangement for the recording to be made. These methods included using the two mirror approach (Lin, I-Chen, Jeng-Sheng, Ouhyoung, Ming 2003 and Whit, Amelia and Lees, 1999) for 3D motion capture, full frontal face capture and finally recording only the mouth and nose area. The marker coordinates on the lip contours were extracted from the recordings and stored in Ms Excel worksheets.

Then, speech analysis was done using cross-correlation of the phonemes used to see if this process could be used for Phoneme recognition. Also, a technique based on Artificial Neural Networks (ANN) was tried to create a user dependant system. In this technique, the speech analysis consisted of programming neural networks by feeding direct speech made up of 44 phonemes and using the critical points of the lip movements as the desired out come.

When the result proved unsatisfactory several other speech processing methods were used to extract the features from the speech signal. These methods included reducing the waves into its wave envelop pattern and extracting the energy levels of the wave using Discrete Fourier Transform.

Experimental results

Cross-correlation Speech analysis was done using cross-correlation of the phonemes used to see if this process could be used for Phoneme recognition. From this method :accurately recognizing a sound is 56.18%. :25.00% phonemes gave ambiguous results. :18.18 % of the phonemes were not recognizable at all.

It is believed that the recognition accuracy of 56.18% is due to the pronunciation distinctness between the phonemes such as /p/, /t/ and /th/, as well as to the small class size. Certain of

phonemes such as /k/ consisting of the unvoiced stop, are not that easily recognized. Sounds with the soft ‘sss’ sounds are extremely difficult to accurately recognize. It is believed that this is caused by the similarity in pronunciation between these phonemes.

ANN A technique based on Artificial Neural Networks (ANN) was tried to create a user dependant system. In this technique, the speech analysis consisted of programming neural networks by feeding direct speech made up of 44 phonemes and using the critical points of the lip movements as the desired out come. Feeding direct sound to the ANN produced large errors and was therefore deemed unsuitable.

When the result from the first method proved insufficient several other speech processing methods were used to extract the features from the speech signal. The second attempt was to train an ANN using the wave pattern envelop and the corresponding key-point coordinates. This method gave better results than the earlier method but was still not satisfactory.

The final method was to extract the energy levels of the wave using Discrete Fourier Transform and training an ANN using this data with again, the key point co-ordinates as the desired outcome. This method gave for more encouraging results as the error when training ANN was very small.

Discussion The cross- correlation method can be used to categorize phonemes into three different groups and to identify them as being in one of these groups but it is not possible to use that method for actual identification of a specific phoneme from an audio speech signal.

The two original methods (feeding direct sound to the ANN and training the ANN using sound envelops) do not produce satisfactory results but using the Fourier transform to process sound waves showed promise. When the ANN where trained using this method gave more satisfactory results than any of the previously tried methods.


238

Design of an All-In-One Billing Meter for Three Wheelers in Sri Lanka

B.G.L.T. Samaranayake


Introduction There is a massive trend in the Sri Lankan society to use Three-Wheelers in the absence of a reliable and punctual public transport service. This has been the practice for the past decade or so and the future is uncertain about of changing the situation. However, still there is no transparent charging system (billing system) for the above three-wheeler taxi services. As a result, clients have to satisfy with whatever the hire demanded by the three-wheeler driver. Hence there is a severe threat of abusing the service and charge unjustifiable amounts of money, and in fact this has been the experience by most of the clients, irrespective of the area of operation of the taxi service in the country. Therefore, there should be a viable technical solution to protect the client and make him pay only the desired amount.

Concerning the owners, since there is no stipulated per kilometer charging system, there is no way for the owner of the three-wheeler (as he may not be the driver in most of the cases) to double check the day’s collection, with the number of kilometers the vehicle has traveled. Hence a reliable mechanism is needed for the owners to keep track of the distance traveled and fuel consumed against the income presented by the driver.

As far as the road network of the country is concerned, in most of the cities, they get flooded with traffic jams especially during the peak hours. In such situations, three-wheelers may have to be kept in queues with their engines on but at zero road wheel speeds. If the vehicle is issued with a fixed amount of fuel, then obviously the distance it can travel reduces compared to that of without traffic jams. Then the driver may find it difficult to convince the owner, at end of the day, the reason why the income dropped while having consumed the entire amount of fuel he has been given. In that case, there should be a technical evidence for the driver to prove his honesty.

Focusing mainly on the above needs of the clients, owners and drivers, an all-in-one

billing meter, has been designed for the three wheelers in Sri Lanka, which will have some additional technically sound features, which will promote the meter to out perform such meters in the import market. The design is presented in the paper.

Methodology The meter uses a pulse counting technique using Hall effect sensors to derive the number of turns of the road wheel, while its prevailing effective wheel diameter will be taken online via coupled electronic and optical methods to derive the distance travelled. This offers mechanical cable free, maintenance free, long-term operation. Vehicle inclination is also sensed to derive whether it is on an ascent or a descent and the engine idle time is the feedback to evaluate the fuel waste during traffic jams. The above parameters are used in an onboard micro controller to execute the relevant calculations. Low cost seven segment displays which can be viewed from distance both by the driver and the clients, is used for the human machine interface with a simple up-down and push button touch panel with mode changing to display the relevant parameters. Further, the same interface touch panel is used to enter the per kilometer charge by the authorities, which is password protected. In addition, it adapts appropriate noise handling techniques to overcome noise interference in the two-stroke and four-stroke internal combustion engine environment.

Results and discussion

Measure and display the distance of the trip The distance traveled is calculated by counting the pulses generated in the coils due to the rotation of the permanent magnets (PM) connected to the driving shaft of the road wheel. The same pulse count is used to derive the speed of the three wheeler. The arrangement of PMs and the corresponding pulse pattern are shown in Figure 1 (a) and Figure 1 (b) respectively.


239

Display the accumulated distance The designed meter to be fabricated is shown in Figure 2. The top row of the display shows the distance traveled for a given trip in kilometers, which may be set to zero at the beginning using the SET button. The same row can be used to display the total distance traveled since fixing the meter. The DISTANCE or ODO modes can be selected using the MODE button. The second row shows the instantaneous speed in km/h, while the bottom row shows the hire. This hire gets updated automatically based on every 100m traveled and / or the engine idling time since the beginning of the trip.

Password protected access to edit the billing rate by the authorities of the governing area This is accomplished using the same display panel as shown in the Figure 2 but in a different mode entered using the MODE button.

Continuously display the due charge as the trip progresses, while taking into account the:

a). Air pressure of tires Since the distance is calculated by counting the number of pulses as was shown in Figure 1(a), it is important that the correct effective road wheel radius is used. This is heavily dependant upon the flatness of the tyre as shown in Figure 3. Therefore it is measured and taken into account in the calculation of the distance so that it results in a more accurate distance calculation.

b). Amount of time spent on traffic jams This is estimated by sensing the idling time of the engine since the beginning of the trip.

c).Elevation gradient of the road, i.e., traveling in mountainous vs., flat areas This is detected by using the electromagnetic sensor arrangement as shown in Figure 4(a) and (b).

Calculate and display the fuel wasted due to traffic jams This is done inside the micro-controller using the engine feedback on idling.

Figure 1(a). Rotation of the PMs connected to the shaft, which drives the road wheel

Figure 1(b). Pulse pattern generated in the coil.

Figure 2. Display screen of the ALL-IN-ONE-BILLING METER

PM1

PM2PM4

PM3

ω

v(t)

v(t)

π/2ω

DISTANCE / ODO (km)

SPEED (km/h)

HIRE (Rs.)

MODE

SET

RESET


240

Figure 3. Effective radius of the road wheel influencing the distance calculation

Figure 4(a). When the two input coils are supplied with the same sinusoidal input signal, two identical sinusoidal signals are induced in the two output coils, provided that the two coils are identical. The black circles are metal balls

Figure 4(b). When the three wheeler is travelling on an inclined plane, the metal balls enter into the coil core increasing the magnetic coupling (reducing the reluctance). Hence the output coil with metal balls inside has a higher voltage induced compared to the coil without the metal balls. This difference is used to detect the elevation and decide the inclination.

(a) Normal Air Pressure Exists (b) Air Pressure decreased,reducing effective radius

Input Waveform

Output Waveformon flat plane

Output Waveformon inclined plane

Input Waveform

Output Waveformon flat plane

Proceedings of the Peradeniya University Research Sessions, Sri Lanka, Vol.12, Part II, 30th November 2007

241

Memory Efficient Algorithm and Closed Form Formulas for Computing Odd

Magic Squares of Higher Order

P.C. Perera

Department of Engineering Mathematics, Faculty of Engineering

University of Peradeniya

Introduction

Magic squares have been studied for at leastthree thousand years, the earliest recordedappearance dating to 2200 BC, in China.In the 9th century, Arab astrologers usedthem in calculating horoscopes, and by 1300AD, magic squares had spread to the West.An engraving by the German artist AlbrechtDurer included a magic square in which theartist embedded the date, 1514, in the formof two consecutive numbers in the bottomrow. Because the concept of a magic squareis so easily understood, magic squares havebeen particularly attractive to puzzlers andamateur mathematicians. In modern mathe-matics, the notions pertaining to magic squa-res are utilized to characterize magic graphsas well as magic cubes. (Jezny and Trenkleret al. 1983 and Adler, Robert Li et al. 1978)

The nth order magic square is an n × n ar-ray consisting of the first n natural numberssuch that the sum along rows, along columnsas well as along two diagonals are all equal

ton(n2 + 1)

2. Of course, given any magic

square, a rotation or reflection will produceanother magic square. Not counting theseas distinct, it is known that there is only one3rd order normal magic square, and there are880 normal 4th order magic squares. Thenumber of distinct normal magic squares in-creases dramatically with its size. For in-stance, there are over 13 million normal mag-ic squares of 5th order. The algorithm de-vised in this endeavor produces only one suchnormal magic square for a given odd natural

number.

Even though the computational aspects oflower order magic squares are fairly simpleand straightforward, those of the higher or-der counterparts demand memory and timeefficient algorithms. The computational timeas well as the memory requirement for thecomputation of n×n magic square are bothof order n2. The unavailability of a closedform expression for the nth order magic squa-re results lengthy source codes. Moreover, asn becomes very large, high memory require-ment makes the computation of nth ordermagic square impossible. In this endeavor,it is attempted to devise a memory efficientalgorithm and formulate a closed-form ex-pression to compute odd higher order magicsquares by formulating de la Loubere typemagic square.

The objectives of this work are to developmemory efficient algorithms in the contextof nth (n mod 2 = 1) order magic square todetermine,

(a) the cell (i, j) ∈ N × N for a given k

satisfying 1 ≤ k ≤ n2, and

(b) the entry k with 1 ≤ k ≤ n2 when thecell (i, j) ∈ N ×N is specified,

where N = 1, 2, ..., n.

Preliminaries

Letting the entry of the ith row and the jth

column of the magic square be xij , the prob-lem of magic square can be formulated as fol-lows. For the sake of notational simplicity,


242

henceforth, unless specified otherwise, theentry of the cell corresponding to the ith rowand the jth column of the nth order magicsquare is denoted by Mn(i, j). Then,

n∑

j=1

xij =n(n2 + 1)

2

for i = 1, ..., nn

∑

i=1

xij =n(n2 + 1)

2

for j = 1, ..., nn

∑

i=1

xii =n(n2 + 1)

2n

∑

j=1

xn+1−j,j =n(n2 + 1)

2

where xij ∈ 1, 2, ..., n2.

It should be noted that the solution of theproblem is not unique. The optimum algo-rithm available at present is used in MAT-LAB. In MATLAB, two n×n arrays are de-clared by the function MESHGRID in theprocess of obtaining the nth order magic squ-are. Then those two n×n arrays are manip-ulated to obtain the nth order magic square.Thus, it is obvious that the demand for thememory is an issue as n becomes large. Tocomprehend the demand for the memory andthe associated complexity of other existingalgorithms, consider the following algorithmused in MATLAB.

function M = magic(n)

n = floor

...(real(double(n(1))));

if mod(n,2) == 1

[J,I] = meshgrid(1:n);

A = mod(I+J-(n+3)/2,n);

B = mod(I+2*J-2,n);

M = n*A + B + 1;

end

In the case of the above MATLAB routine,A, B, I and J are of nth order square matri-ces. Thus, the memory requirement and thecomputational time pertaining to the above

algorithm may be very high as n becomesvery large. The case is the same for the otherexisting algorithms used for computation ofmagic squares. The algorithm devised in thiswork requires much less computer memoryas well as computational time.

The main result

The following results are conjectured and pr-oved in this work. For the sake of brevity,their proofs are not presented here.

Theorems

Theorem 1. For a given n and k satisfying

n mod 2 = 1 and 1 ≤ k ≤ n2,

Mn (a, b) = k,

where

a =

(

(n + 2k − 3)

2−

⌊

k − 1

n

⌋)

mod n

+1

and

b =

(

n + k − 2 − 2

⌊

k − 1

n

⌋)

mod n

+1

Example 1. If n = 7, using the above algo-

rithm, the MATLAB routine

n=7;

for k=1:n^2,

a=mod((n+2k-3)/2+

...floor((k-1)/n),n)+1;

b=mod((n-k-2+

...2*floor((k-1)/n),n)+1

M(a,b)=k;

end;

produces 7th order magic square as

30 39 48 1 10 19 2838 47 7 9 18 27 2946 6 8 17 26 35 375 14 16 25 34 36 45

13 15 24 33 42 44 421 23 32 41 43 3 1222 31 40 49 2 11 20


243

Remark 1. In the light of Example 1, it is

obvious that this algorithm converts a prob-

lem which demands the manipulation of two

n × n arrays, to a problem of simplifying

a simple expression involved two variables,

namely, n and k.

Theorem 2. Denoting 1, 2, ..., n by N ,

for a given cell (i, j) ∈ N × N , the cor-

responding entry Mn(i, j) of the nth order

magic square is given by

Mn(i, j) = n

[

i − j +(n − 1)

2

]

mod n+

(2i − j − 1) mod n + 1.

Example 2. If n = 11, using the above

algorithm, the MATLAB routine

n=11;

for j=1:n,

M(2,j)=n*mod( i-j+(n-1)/2,n)+

...mod(2i-j-1,n)+1;

end;

produces the set of entries in the second row

of the 11th order magic square as

80 93 106 119 11 13 26

... 39 52 65 67

Conclusions

Unlike the other algorithms associated withmagic squares, this algorithm can be con-verted to any high level language very easilydue to the absence of manipulations of ar-rays. Nevertheless, it should be noted thatthe above algorithms are not applicable forthe even order magic squares. Moreover, theimprovement of the time efficiency associ-ated with the algorithms developed in thisendeavor are quite insignificant. Hence, theabove facts should be considered in the pro-cess of generalizing and extending the af-orementioned algorithms to make them ap-plicable for the computation of a magic sq-uare of any order.

References

Jezny, S. and Trenkler, M. (1983) Charac-terization of magic graphs, Czechoslo-

vak Math. Journal, 33(2), 435-438.

Adler, A. and Robert Li, S.Y. (1978) MagicN-cubes and prouhet sequences, Amer-

ican Mathematical Monthly, 84(1), 618-627.


244

An Efficient Algorithm to Compute the Square of a Binary Number

M.G. Arlis1 and P.C. Perera2

1Independent Researcher

2Department of Engineering Mathematics, Faculty of Engineering


Introduction

Much of contemporary research is geared todevelop and devise efficient algorithms thatare applicable in solving very complicatedmathematical problems. Nevertheless, thedevelopment of efficient algorithms to per-form calculations that are used ubiquitously,enhances the speed of almost every calcula-tion performed by a computer. In this en-deavor, it is aimed at developing an efficientalgorithm that can be used in squaring bi-nary integer.

It should be noted that for the process ofsquaring only the significant figures of thenumber under consideration do matter. LetN ∈ N be a binary number. Let k be thelargest nonnegative integer such that 2k|N .Thus, the significant figures can be obtainedby chopping off the last k integers of N . Let-

ting N =N

2k, the following procedure can be

used to compute N2 and N2 as well.

Preliminaries

Since the square of unity is trivial, supposeN 6= 1. Let p1 be the least positive inte-ger such that m0 = N < 2p1 . It is ob-vious that p1 ≥ 2. Define m1 by letting2p1 − m1 = N = m0, it turns out that

m20 = N2 = 2p1 (2p1 − 2m1) + m1

2,

and m0 > m1. If m1 6= 1, let p2 be the leastpositive integer such that m1 < 2p2 .

Obviously, p2 ≥ 2. Letting 2p2 − m2 = m1,it turns out that

m21 = 2p2 (2p2 − 2m2) + m2

2,

for some m2 with m1 > m2. Since the fi-nite sequence mi is a strictly decreasingsequence of odd positive numbers, ml = 1for some l ∈ N. Iteratively, it can be shownthat

N2 = 1 +

l∑

i=1

2pi (2pi − 2mi) . (1)

The terminating condition for the algorithmis that mi = 1 for some i ∈ N.

It turns out that for i ∈ N, 2pi − 2mi canbe computed simply by means of shift regis-ters. See the following example.

The main result

Theorem 1. Let N be a binary integer

consisting of a significant part with L binary

transitions. Then

N2 = 1 +

L∑

i=1

2pi (2pi − 2mi) . (2)

Remark 1. In the light of Theorem 1, it

can be concluded that the steps required for

the computation of N2 is exactly the transi-

tions present in the significant part of N .

The application of this algorithm is outlinedwith the help of the following examples.


245

Examples

Example 1. Let m0 = 11011012. The value

of p1 = 7 since 10000002 < 11011012 <

100000002. (p1 is, in fact, equal to the num-

ber of digits of m0.) m1 = 100000002 −11011012 = 100112

2p1 − 2m1 = (100000002 − 1001102)= 10110102

It turns out that

m0 = 1 1 0 1 1 0 1

a1 = 1 0 1 1 0 1 0

It can be observed that a1 = 2p1 − 2m1 can

be obtained simply by shifting the bits of m0

by one place to the left while introducing a

’zero’ for the least significant bit.

Example 2. Let b = 11100012.

m0 = 1 1 1 0 0 1

m1 = – – – 1 1 1

m2 = – – – – – 1

and

2p1 − 2m1 = 1 1 0 0 1 0

2p2 − 2m2 = – – – 1 1 0

Note that 2pi−2mi is directly obtained by

shifting mi−1 by one left shift while discard-

ing the most significant bit of mi−1. The

number mi is obtained by keeping the least

significant digit of mi−1 as it is, while com-

plementing the other bits.

Since, in this case, it yields

N = m0 = m22 +

2∑

i=1

2pi (2pi − 2mi) , (3)

where m2 = 1, we have

2p1 (2p1 − 2m1) = 1 1 0 0

2p2 (2p2 − 2m2) = – – – –

m22 = – – – –

N2 = 1 1 0 0

...

1 0 – – – – – –

– – 1 1 0 – – –

– – – – – – – 1

1 0 1 1 0 0 0 1

Note that p1 = 6 and p2 = 3. It can be

observed that 1110012 = 57 and 572 =3249 = 1100101100012.

Discussion

The terminating condition for the algorithmis that mi = 1 for some i. Thus, if m1 6= 1,letting m2 be the least positive integer suchthat m1 < 2m2 , add m1 − m2 number of ze-ros to the end of the current answer in theregister and repeat the aforementioned stepsuntil mi = 1 for some i. Note that 2pi −2mi

is directly obtained by left-shifting mi−1 byone bit while discarding the most significantbit of mi−1. Moreover, mi is obtained bykeeping the least significant digit of mi−1 asit is, while complementing the other bits.

If the binary integer N of our interest con-sists of m significant bits, N2 has exactly 2mor 2m − 1 significant bits. Clearly, when N

becomes large, the overflow error occurredcan be eliminated by using several registersin series. The above fact is not possible inthe case of other existing algorithms.

Conclusions

In Phillips et al. (2001), the square of longintegers was obtained by removing repeateddigit products from the accumulation treewhich is called optimized squaring using pre-computed partial products. It can be shownthat the algorithm devised in this paper su-persedes the method of optimized squaringusing pre-computed partial products present-ed here. Shifting involved in the regular pro-cess of squaring is not an issue in the con-text of this new algorithm. Additions andsubtractions are also kept minimal in thiscase.

References

Phillips, B. (2001) Optimized squaring oflong integers using pre-computed par-tial products, Proceedings. 15th IEEE

Symposium on Computational Arithm-

etic


246

Modified Stepping Stone Algorithm for Solving Large-Scale Balanced

Transportation Problems

B.M.R.K. Basnayake and P.C. Perera



Introduction

The optimal solution to a transportation pr-oblem is sought by employing the SteppingStone algorithm(SS), starting from some ini-tial basic solution. Some attempts have beenmade et al Keri to reduce high computa-tional time associated with solving of trans-portation problems involving very large num-ber of sources and destinations. In this en-deavor, it is aimed at developing an algo-rithm which outperforms all Stepping Stonelike algorithms in terms of computationaltime required for solving large-scale balancedtransportation problems. The algorithm thatis devised and tested in this work, is calledModified Stepping Stone algorithm(MSS).

Derived Stepping Stone algorithm

(DSS)

A balanced transportation problem with m

and n sources and destinations can be formu-

lated as Minimization of

m∑

i=1

n∑

j=1

cijxij such

that

m∑

i=1

xij = sj for j = 1, 2, ..., n and

n∑

j=1

xij = di for i = 1, 2, ...,m. In the case

of DSS, at kth iteration, for each open cell(i, j) for which zij − cij is negative, instead

of zij − cij , it is considered M(k)

ij (zij − cij),

where M(k)

ij is the maximum value that canbe assigned for the cell (i, j) with the solu-tion at the kth iteration.

There exist examples for which DSS requiresapproximately 20% more steps than SS. Seegraph 1. Nevertheless, DSS demonstrates

relatively faster convergence if for1

5< r <

1

2,

card ((i, j) : zij − cij < 0)

(m − 1)(n − 1)> r and

σs

s≪ 1,

where S = cij − zij : zij − cij < 0, s andσs are respectively the mean and the stan-dard deviation of the set values of S. It canbe shown that card ((i, j) : zij − cij < 0)

andσs

sare functions of mn − m − n + 1

and the iteration number k. It should benoted that the derivation of closed forms ofcard ((i, j) : zij − cij < 0) and

σs

smay be

extremely tedious or impossible. Despite theunavailability of closed forms of the abovefunctions, it can be shown that


(m − 1)(n − 1),

decreases andσs

s,

increases as the number of iterations k be-comes large. Since, m and n are fixed for agiven problem, it follows that


decreases with k.


247

Modified Stepping Stone algorithm

(MSS)

The above facts motivates us to revert tothe SS after the first few iterations by DSS,shows the most favorable results in termsof speed of convergence. According to theaforementioned description, tt turns out thatthe combined application of SS and DSS wh-ich is, in fact, MSS, produces the most favor-able results. Topologically, the basic differ-ence between the SS and MSS is that whilethe former always searches for the directionof the steepest decent, the latter choses thedirection along which the highest fall is pos-sible on the simplex S ⊂ N

mn.

Results

For the sake of brevity, the results obtainedfrom SS, DSS and MSS for a balanced trans-portation problem with 10 sources and 8 des-tinations are given in Graph 1.

-

6

iter. no.

total cost

• − SS − DSS⋆ − MSS

0 1 2 3 4 5 6 7 8 9 10

•⋆

•

⋆•

⋆

•

⋆

•

⋆•

⋆•

•

Graph 1

For large scale balanced transportation prob-lems the behaviors of SS and MSS turn outto be significantly different from each other.Consider the results obtained for a balancedtransportation problem with 200 sources and150 destinations which are provided in Graph2.

-

6

iter. no.

total cost

• − SS − DSS⋆ − MSS

0 5 10 15 20 25 30 35 40 45 50

•⋆

•⋆

•⋆ •

⋆•

⋆•

⋆

•

•

Graph 2

Discussion

Let SS requires p iterations to converge tothe optimal solution starting from an initialbasic solution for a transportation problemwith m and n sources and destinations re-spectively. Then, by applying DSS for the

first p

⌊

mn − m − n + 1

γ

⌋

followed by SS re-

quires only αp iterations where γ ∝ (mn)β

for some β > 0 and α ∈ (0, 1 − f(m,n)) with0 < f(m,n) monotonically increasing withmn having unity as its least upper bound.

Conclusions

It can be concluded that MSS converges fast-er than SS for the large-scale balanced trans-portation problems. In terms of computa-tional simplicity, MSS supersedes the algo-rithm developed by (Keri et al 1972). Itcan also be concluded that the significance ofthis algorithm is enhanced when m,n → ∞.Nevertheless, the following avenues are openfor future work. Even though


andσs

sare known to be the functions of

mn − m − n + 1 and the iteration numberk, models for those functions are yet to be


248

determined. A statistical model may be vi-able though the formulation of precise ex-pressions for the above functions is extremelytedious or impossible. More importantly, theparameters α, β, γ as well as the functionf(m,n) are to be determined.

References

Keri, (1972) A modified stepping-stone al-gorithm for the Transportation Prob-lem, Int. J. of Theoretical and Applied

Statistics, 5 (2) 327-331


249

Controller Design and Implementation for Cost Effective Mobile Robots

I.B. Wijayasinghe and B.G.L.T. Samaranayake*


Introduction ROBOCON is an annual robot competition organized by the Asia – Pacific Broadcasting Union (ABU) among the countries in the region. In 2007, the game plan included design and construction of two types of mobile robots, namely manually operated mobile robot, i.e., the manual machine and automatic mobile robot, i.e., the automatic machine. Both the types are supposed to pick hollow cylindrical objects called pearls and put them around a pole called the island. This operation with the manual machine and automatic machines are shown in Figures 1(a) and 1(b) respectively. Depending on the game strategy, there are significant differences between the accessories used in the two types of machines. However, the driving platforms, which need controllers, are identical in terms of the designed acceleration, maximum speed, maneuverability, weight, height of the top most point, ground clearance, etc. Out of them, the main criterions of the design are the speed and the maneuverability as the machines have to travel about 50m in total in the game field in 3 minutes, where the field is of a polygon shape. The speed requirement is over 2 ms-1 for a machine of weight of approximately 25 kg with all its accessories connected.

System modeling Permanent Magnet DC motors are used in the drive platforms, in order to achieve the desired dynamics, because the torque of the stepper motors, which is the other alternative, drastically drops at higher speeds. The block diagram model as shown in Figure 2 is used to model the Permanent Magnet DC motor from the input voltage to the output angular velocity (Figure 3). In the block diagram, La and Ra are the armature inductance and resistance respectively and K is the torque constant, while J being the rotor moment of inertia. Since the manufacturer specified values for the above parameters were not available for the motors, they were identified by measuring armature current Ia and the speed ω for a set of input voltages Va.

Neglecting the viscose friction, Ia is assumed to be constant at steady state. It can be related to speed as

KRI

VK

aa−⎟⎠⎞

⎜⎝⎛=

1ω (1)

which is an equation of a straight line with gradient 1/K and intercept - Ia Ra/K. The experimental dataset is shown in Table 1 and Ra was calculated for each data set, and the average was taken as the true value of Ra. The armature current dynamics (Figure 4) corresponding to a voltage step input, with the motor shaft on no load, are used to calculate the parameters La, Ts and J. With s being the Laplace operator, the voltage and current can be related as

)(1)( sVRsL

sIaa

a +=

(2)

Hence the electrical time constant τe= La/ Ra can be calculated from the rise time of the current waveform in Figure 4 and assuming τe << τm, where τm is the mechanical time constant. In the current falling, τm =J Ra /K2 is dominant and it can be used to evaluate the relevant parameters. The armature current in steady state is related to the torque T by T=K Ia. The effect of the mass (M) of the mechanical structure can be modeled by

ωsMr

T 2

2= , (3)

where r is the radius of the road wheels. Hence the resultant inertia felt by the motor can be given by,

2

2MrJJJ ws ++= . The identified

motor parameters are listed in Table 2, which are used in the controller design.

Controller design The controller mainly consists of speed control and position control. The purpose of the speed controller is to maintain the road wheel speed


250

at the desired value depending on the expected motion profile. Two loops are implemented, one for each motor. But the two loops are coupled as these machines do not have a differential for driving in circular or curved paths and the differential action is implemented electronically through the controllers. Pole placement design technique is used to tune a Proportional Integral (PI) controller (Kp + Ki/s), where the gains have been set to obtain a closed loop bandwidth of 10Hz, where the Bode amplitude diagram is shown in Figure 5. An outer position controller is used to ensure the correct position profile is followed. Since the integral action is inherited from the speed loop only a Proportional controller (gain 0.01745) is used here.

Results and conclusions Speeds of the two road wheels, when they are under different load torques, without the position controller is shown in Figure 5. The corresponding difference of the angle of rotation of the two wheels is shown in Figure 6. The same scenario, but with the position controller implemented, is shown in Figures 7 and 8 respectively. It is observed that position controller effectively brings the angular position difference to zero effectively.

Figure 1 (a): Manual Machine entering a Pearl to the Island

Figure 1 (b): Automatic Machine has just

entered a Pearl to the Island

Figure 2: DC Motor Model

Heading 2

Figure 3: Angular Velocity vs. Voltage

Figure 4: Shape of the Current Trace


251

Table 1: Steady State Characteristics

Voltage

/(V)

Current

/(A)

Velocity

/(rpm)

Ra

/(ohms)

4 0.58 623 0.6742

5 0.61 792 0.6754

6 0.65 958 0.6929

7 0.68 1134 0.6336

8 0.7 1311 0.5793

9 0.73 1482 0.5684

10 0.76 1657 0.5278

11 0.79 1826 0.5344

12 0.81 2004 0.4827

Table 2: Calculated Parameters Parameter Value

K 0.05532

Ra 0.5962

La 0.001908

Js 0.0001242

Jw 0.0002967

eds of the two wheels without Position Controller

Figure 6: Angular position differences without Position Controller

Figure 7: Speeds of the two wheels with the Position Controller

Figure 8: Angular position differences with the Position Controller

Figure 5: Speeds of the two wheels without Position Controller


252

An Efficient Algorithm to Compute the Reciprocal of a Binary Number

P.C. Perera



Introduction

In recent times, much research has been fo-cused on developing both time and mem-ory efficient algorithms for solving compli-cated mathematical problems. Contrarily,very efficient algorithms for calculation ofsimple operations that are performed veryfrequently, tremendously improve almost ev-ery complicated computation performed by acomputer. The algorithm developed in thiswork may be used to compute the recipro-cal of a binary integer while eliminating theunderflow errors occurred due to the limi-tations of length of registers employed in aCPU.

Preliminaries

Let N be the binary integer of which thereciprocal should be computed. Denote A =0, 1. To avoid trivialities, let the least sig-nificant digit of N be 1. Suppose k ∈ N is thesmallest number such that N < 2k. Then

N =

k−1∑

i=0

ai2i, where ak−1 = 1 and ai ∈ A

for i ∈ 1, 2, ..., k − 2. The assumption onthe least significant bit makes a0 = 1. Itturns out that

1

N=

1k−1∑

i=0

ai2i

=1

2k −k−1∑

i=0

bi2i

,

where a0 = b0 = 1 and bi = ai for 1 ≤ i ≤k − 1.

The binomial expansion of1

1 − xyields that

1

N=

1

2k

∞

∑

j=0

(

k−1∑

i=0

bi2i−k

)j

.

Considering the binary expansion of 1

N, we

have

1

N=

1

2k

∞

∑

j=0

(

k−1∑

i=0

bi2i−k

)j

=

2−k +

∞

∑

i=k+1

di2−i,

(1)

where dl ∈ 0, 1 is the binary digit corre-sponding to the lth binary place of the binarysequence of the reciprocal of N .

The objectives of this work are

(i) to determine the number of binary pla-ces to be determined in order to obtainthe exact answer, and

(ii) to devise an efficient algorithm to de-termine di for i ≥ k + 1.

Theorems and lemmas

For the sake of brevity, the proofs of thelemma and the theorems presented in thissection are omitted in this paper.

It is a known fact that the binary sequenceof every rational number Q has a recursivesubsequence in it.

Example 1. Let x =1

7. Clearly x ∈ Q,


253

and1

7= 0.142857142857... = 0.142857. If

x =1

1012

∈ Q, then1

1012

= 0.00110011...2 =

0.00112.

Lemma 1. If N is a prime, N |2N−1−1 and

the upper bound for the length of the string

repeated in the binary sequence of 1

Nis N−1.

For a given prime N , there exists a ∈ N such

that N |2(N−1)/a − 1 and the exact length of

the string repeated in the binary sequence of1

Nis N−1

a.

Example 2. Recall that N = 17 is a prime.

As the second assertion of Lemma 1, the

smallest number in the sequence

2i − 1N−1

i=1

which is divisible by 17 is 255 which is

2(17−1)/2 − 1 or 2(N−1)/a − 1 with a = 2.

For composite N , the following theorem isapplicable.

Theorem 1. Let N ∈ N and the prime fac-

torization of N be given by N = pr1

1 pr2

2 ...prm

m .

Suppose ai is the largest positive integer such

that pi|(

2(pi−1)/ai − 1)

for i = 1, 2, ...,m.

Then there exists a least positive integer N

such that N |2N − 1 and is given by

N =

(

(p1 − 1)

a1

pr1−1

1 ,(p2 − 1)

a2

pr2−1

2 , ...,

(pm − 1)

am

prm−1m

)

.

Moreover, the exact length of the recursive

portion of the binary sequence of1

Nis N .

Example 3. Let N = 119 = 7 × 17. Since

7|23 − 1 and 17|28 − 1, as in Theorem 1,

the length of the recursive binary sequence is

3 × 8 = 24. In particular

1

119=

12

11101112

=

0.0000001000100110101110012

The required binary digits in the sequencecan be determined by constructing a denom-inator dependent difference equation as indi-cated in the following theorem. The sum of

the outputs produced by the difference equa-tion converges to the reciprocal of our inter-est.

Theorem 2. Let N =

k−1∑

i=0

bi2i where bi ∈ A

∀ i. Then1

N=

∞

∑

i=1

2−ixi and yi for i = N

are the sequence of solutions to the kth order

difference equation yn+k =

(

k−1∑

i=1

biyn+i

)

+

b0yn with initial conditions yi = 0 for i =1, ..., k − 1 and yk = 1 such that the se-

quence zj∞

j=1has the property zr−k+1 =

∣

∣

∣

∣

∣

r∑

i=1

2−ixi −r∑

i=1

2−iyi

∣

∣

∣

∣

∣

→ 0 as r → ∞.

Example 4. Let N = 15. Thus, N =11112. The corresponding difference equa-

tion is yn+4 = yn with initial conditions yi =0 for i = 0, 1, 2 and y3 = 1. Thus it turns

out that

yn =

1 if n = 4k − 10 otherwise

y4 = y5 = y6 = 0, y7 = 1, y8 = y9 =y10 = 0... and by continuing this process

12

11112

= 0.000100010001.. = 0.0001 can be

computed accurately.

Example 5. Let N = 119. Thus, N =11101112. The corresponding difference equa-

tion is yn+7 = yn+3 + yn with initial condi-

tions yi = 0 for i = 0, 1, ..., 6 and y7 = 1.Thus it turns out that y8 = y9 = y10 =y12 = y13 = y16 = y17 = y20 = y24 = 02,

y11 = y14 = y15 = y19 = y21 = y23 =y27 = y28 = 12, y18 = 102, y22 = y25 = 112,

y26 = 1002... and after 26th iteration, trun-

cating the tail after the 24th binary place (in

the light of Example 3), it yields that

12

11101112

=

0.0000001000100110101110012.


254

Conclusions

The algorithm outlined in this paper out-performs all of its counterparts in the con-text of division of integers and is applicablewhile utilizing registers with any length asopposed to the other available algorithms.The aforemention method which is based ondifference equations, guarantees faster con-vergence and accurate results when all ormost of the binary digits of N are equal to

’one’. Otherwise, the convergence may beslow requiring large number of iterations forthe exact solution. Even though this ap-proach is promising, avenues are open forimprovements.

References

Bennett, W.S. (1973) Quotient generationwith conventional binary multipliers,Proceedings of IEEE, 61(5), 664-665


255

Error Correction Model for Predicting the Carbon Dioxide Emissions of a Coal-based High-income Economy

R. Shanthini1 and K.Perera2* 1Department of Chemical and Process Engineering, 2Department of Engineering Mathematics,

Faculty of Engineering, University of Peradeniya Introduction Oil shock of the 70s has been the major factor that caused structural breaks in the ever-increasing trend in carbon dioxide (CO2) emissions experienced by high income economies such as United States, Japan, France and Austria (see, Unruh and Moomaw, 1998; Friedl and Getzner, 2003; Shanthini and Perera, 2006). The ever-increasing trend in the CO2 emissions of Australia, despite it being a high income economy, remains relatively unaffected owing to perhaps its dependence on coal as fuel (BP, 2006; World Bank, 2007). This paper seeks to identify the effect the increasing income has upon the CO2 emissions of Australia, particularly because it is one of the two countries that has defied the Kyoto Protocol (UNFCCC, 1997) that assigned mandatory greenhouse gas emissions limitations to the signatory nations.

Since both income and emissions data of Australia are trending non-stationary time series, an ordinary least square regression model developed based on this data can be spurious (Granger and Newbold, 1974). In this study, we show that there exists a cointegrating relationship between the income and emissions non-stationary time series, and thus the long term effect that income has on emissions can be captured using the error correction modeling approach proposed by Engle and Granger (1987).

Data analyses The annual CO2 emissions (denoted by CO2) and the gross domestic product per capita (denoted by GDPpc) data for Australia used in this study, obtained from World Development Indicators (World Bank, 2007), are shown in Figure 1. The unit of CO2 is Mt (mega tonnes = 109 kg) of CO2 and that of GDPpc is thousands of constant 2000 US$. The time span used for modeling is 1960 to 1996, which makes available the emissions data from 1997 to 2003 for model validation.

The results obtained from regressing CO2 on GDPpc, ln(CO2) on ln(GDPpc) and ln(CO2) on 1/ln(GDPpc) using the ordinary least square (OLS) procedure are given in Table 1. In all cases, the R2 statistics are very high. The low values of Durbin-Watson (dw) statistics indicate the presence of serial correlation among the residuals of the respective regressions. The problem is, however, more than just the presence of auto-correlated residuals. It is the fact the time series considered are all nonstationary as revealed by the results of Augmented Dickey-Fuller (ADF) test carried out to test the presence of unit roots. Regressing one nonstationary time series on the other is known to give significant statistical correlation, such as high R2, between the variables, even though the two variables may not be related at all.

In order to determine if there exists an equilibrium relationship between the nonstationary time series of our interest, i.e. if these series “move together” over time, we tested the residuals of the respective regression models shown in Table 1 for stationarity using the ADF test. The results showed that the residuals are stationary at the 5% level of significance for the first two regression models and at the 10% level of significance for the last regression model tabulated in Table 1. Therefore, we concluded that the respective time series are cointegrated, which is indeed a clear proof for the existence of an equilibrium, i.e. a long-term, relationship between the cointegrated time series (Engle and Granger, 1987; Stock and Watson, 1988).

Results: Error correction model The error (or equilibrium) correction model (ECM) between two cointergrated first-difference stationary variables, y and x, could be written (Engle and Granger, 1987) as


256

tt

n

jjtj

t

m

iitit

dECTxc

xcybay

ε++Δ+

Δ+Δ+=Δ

−=

−

=−

∑

∑

11

01 (1)

where y is CO2 or ln(CO2), x is GDPpc or ln(GDPpc) or 1/ln(GDPpc), and the error correction term ECT, expressed as

intercept,*slope −−= ttt xyECT is the residual of the cointegrating regression obtained using the OLS procedure. The respective slope and the intercept values could be obtained from Table 1. The coefficients of ECM in Eq. (1) estimated using the Engle Granger 2-Step Method (Engle and Granger 1987), and other relevant statistics are tabulated in Table 2.

Discussion The coefficients of ECT, given by the values of d in Table 2, show that the error correction term in Eq. (1) has significant effect on the otherwise difference model in all three cases analysed. The AIC and BIC values of Table 2 make the Linear Model inferior to the Ln and the Inverse Models. Of these two, the Inverse Model is superior to the Ln Model since the Ln Model fails the tests for the normal distribution of the residuals (as testified by the P-values corresponding to the Shapiro-Wilk, Kolmogorov-Smirnov, Cramer-von Mises and Anderson-Darling tests). Moreover, the dw of the Inverse Model, being close to 2, also makes it clear that the Inverse Model is the model to be used for predicting the future CO2 emissions in Australia.

Figure 2 shows the emissions predicted by the Inverse Model in comparison to the other two models and the actual emissions. The GDPpc value used for model prediction is the actual value until 2005 and after that it is generated using an annual GDPpc growth rate of 2.135%, which is the average growth rate for Australia during the period 1961 to 2005 (World Bank, 2007). The CO2 value used for model prediction is the value predicted by the model considered, except for the 1960 value. Figure 2 shows that the long term predictions made using the Inverse Model trace the trend of the actual emissions much better than the other two models.

Conclusions Australian carbon dioxide emissions has a long term tendency to keep growing with the GDP

per capita growth in accordance with the relationship given by,

2.6860,)1(1635.3)(3233.6)1(CO7183.0)(CO 22

+−+−−=

txtxtt

where x = 1/ln(GDPpc), if there is a crisis in the oil supply or not. It is made possible owing to Australia being a heavy user of coal, which is available in abundance in her soil. In 2004, coal-based energy generation in Australia accounted for 44.6% of the total (BP, 2006) and coal-based electricity generation accounted for 79.3% of the total (WDI, 2007).

The model above, developed in this study, predicts that Australia would have a total of 440 Mt CO2 emissions in 2012, whereas Kyoto Protocol allows only 294 Mt of emissions in 2012, which is 8% above the 1990 emissions level. This means, in 2012, Australia would be emitting 50% above the emissions allowed by the Kyoto Protocol in order to maintain its GDP per capita growth at a minimum of 2.135%. The strong link between the GDP per capita growth and the emissions as established in this study would probably explain why Australia rejected Kyoto Protocol.

Acknowledgement University Research Grant RG/2006/28/E is gratefully acknowledged.

References BP (2006) BP Statistical Review of World

Energy June 2006, Downloaded on 02.02.2007 from http://www.bp.com/statisticalreview

Engle, R.F. and Granger, C.W.J. (1987) Co-integration and error correction: representation, estimation and testing, Econometrica, 55(2), 251-76.

Friedl, B. and Getzner, M. (2003) Determinants of CO2 emissions in a small open economy, Ecological Economics, 45, 133-48.

Granger, C.W.J. and Newbold, P. (1974) Spurious regressions in econometrics, Journal of Econometrics, 2, 111–120.

Shanthini, R. and Perera, K, (2006) Oil price fluctuation incorporated models for carbon dioxide emissions and energy consumption of high-income economies, accepted for publication in Ceylon Journal of Science: Physical Sciences, Volume 13.

Stock, J.S. and Watson, M. (1988) Variable trends in economic time series, Journal of Economic Perspectives, 2(3).


257

UNFCCC (United Nations Framework Convention on Climate Change), 1997, “Kyoto Protocol”, http://unfccc.int/kyoto_protocol/items/2830.php

Unruh, G.C. and Moomaw, W.R. (1998) An alternate analysis of apparent EKC-type

transitions, Ecological Economics, 25, 221-9.

World Bank (2007) World Development Indicators, Online, Downloaded on 27.7.2007 from http://publications.worldbank.org/ susbcriptions/WDI/.

Table 1. Coefficients and other relevant statistics of the ECM

Model R2

(%) Adj R2

(%) dw Root MSE AIC BIC

CO2 = 23.498 GDPpc -131.427 0.977 0.977 0.74 9.792 171 173 Ln(CO2) = 1.750 ln(GDPpc) + 0.645 0.984 0.983 0.93 0.047 -224 -222 Ln(CO2) = -11.217 [1/ln(GDPpc)] + 9.535 0.976 0.976 0.66 0.057 -210 -208 Note: P<.0001 for both the intercept and slope coefficients, and dw, MSE, AIC and BIC stand for Durbin-Watson, Mean Square Error, Akaike-Information Criterion and Schwarz Bayesian Information Criterion, respectively.

Table 2. Coefficients and other relevant statistics of the ECM

Linear model:

ECM with y = CO2 and x = GDPpc

Ln model: ECM with y = ln(CO2)

and x = ln(GDPpc)

Inverse model: ECM with y = ln(CO2) and

x = 1/ln(GDPpc) a, bi, cj of Eq. (1) Set to 0 since the OLS estimates of them are not significant (i.e. P>0.05) C0 of Eq. (1) 13.5916 (P < 0.0001) 1.0071 (P < 0.0001) -6.3233 (P < 0.0001) d of Eq. (1) -0.3374 (P = 0.0059) -0.4125 (P = 0.0019) -0.2817 (P = 0.0136) R2; Adj R2 0.461; 0.429 0.508; 0.479 0.452; 0.419 dw 1.695 1.649 1.821 F-valve 14.52 (P < 0.0001) 17.58 (P < 0.0001) 14.03 (P < 0.0001) Root MSE 6.58173 0.03365 0.03552 AIC; BIC 137.6; 139.8 -242.3; -240.0 -238.4; -236.1 Chi-Square for heteroskedasticity 0.89 (P = 0.8270) 3.27 (P = 0.3513) 2.44 (P = 0.4862)

Shapiro-Wilk P = 0.2325 P = 0.0309 P = 0.5158 Kolmogorov-Smirnov P > 0.1500 P < 0.0100 P > 0.1500 Cramer-von Mises P = 0.1325 P = 0.0144 P > 0.2500 Anderson-Darling P = 0.1488 P = 0.0154 P > 0.2500

Figure 1. CO2 emissions and GDP per capita time series of Australia from 1960 to 2003

Figure 2. CO2 emissions, actual and predicted


258

Experimental Investigation of Condensation Heat Transfer Coefficient of Refrigerants during in Tube Condensation

L. Rajapaksha* and Y.M.C.E.K. Abeykoon

Department of Mechanical Engineering, Faculty of Engineering, University of Peradeniya Introduction Heat transfer performance of a refrigerant is an important aspect of the design of new refrigeration systems or retrofit of existing ones. Though there are accurate and sufficient heat transfer performance data and correlations for established and well-known refrigerants, data for alternative fluids are not yet well established or available in public domain. This situation makes experimental investigation of heat transfer performance of alternative refrigerants important. This paper briefly describes the design and fabrication of a test rig to find the condensation heat transfer coefficients of mixture refrigerants in plain tubes in the presence of lubricant, and presents initial results obtained for R134a. The results are compared with theoretical values obtained using correlations to demonstrate the validity of the measurements so that the procedure could be extended to refrigerant mixtures.

Heat exchangers of the test rig were initially designed using selected correlations for common refrigerants. Figure 1 presents a schematic of the test rig fabricated as a part of the research, and available at the Applied Thermodynamics Laboratory of the University of Peradeniya. The test rig includes an open type compressor with provision to vary the refrigerant volume flow rate by varying the flow speed. It also includes a desuperheater, condenser, pre heater and evaporator. There are

three separate fluid circuits or loops; refrigerant, cooling water and heating water, in the apparatus. The pre heater provides a measurable thermal load to the evaporator for the steady running for the system. Heat given up by condensing the refrigerant is measured using the temperature rise of a known flow rate of cooling water.

Test rig design, assembly and running The design of the rig includes sizing the heat exchangers, compressor, expansion valve and refrigerant pipes. Instrumentation of the test rig is another important aspect where sensing elements for pressure and temperature of the refrigerant have to be embedded into the rig accurately, particularly to capture the parameters during phase changing flow.

Sizing the evaporator and the condenser was based on the log mean temperature difference (LMTD) heat exchanger design method. Theoretical values of convective heat transfer coefficient of the refrigerant were obtained using Dittus and Boelter (1985) and Shah (1979) correlations. A counter flow configuration is used in both heat exchangers and they are arranged as concentric tube (tube in tube) heat exchangers and thermally insulated.

Figure 1. Schematic diagram of the test rig

Evaporator

Pre-heater De-super heating condenser

Condenser


259

The refrigerant flow rate was varied by varying the speed of the compressor. During testing, the evaporator was loaded using a stream of hot water generated with an electric heater. During the test the inlet refrigerant to the main condenser must not be in a superheated state. Therefore, the flow rate of water and refrigerant should be adjusted as necessary to achieve this. The flow rate could be measured to a precision of ± 0.0001 m3 and temperature to a precision of ± 0.1 oC. The refrigerant pressure and temperature at the inlet and outlet of the condenser section is measured with pressure transducers and thermocouples, respectively.

The thermo-physical properties of refrigerants were obtained from a refrigerant property database which uses all the recent correlations and mixing rules to estimate refrigerant properties (McLinden et al., 1998).

Data reduction In-tube average heat transfer coefficient, hr-av, is calculated from the expression for overall heat transfer coefficient U as given in Eq (1).

in

out

outwavr ddln

21

dh1

Kh1

π−−

π=

− (1)

Where, K is the thermal conductivity and, din and dout represent inner and outer diameters of the tube respectively.

The waterside heat transfer coefficient, hW, is obtained using Dittus-Boelter correlation (Dittus and Boelter, 1985). The overall heat transfer coefficient per unit length of the test section can be estimated using Eq (2), where C and m are specific heat and mass flow rate, L is the length of the test section, ΔTm is the log mean temperature difference, ant Tw is the water temperature.

m

2w1wwWTL

)TT(mCUΔ

−= (2)

Results and discussion Table 1 presents some of the initial results obtained with refrigerant R134a, after commissioning the test rig. These give an idea of the order of magnitude of the difference between average in-tube condensation convective heat transfer coefficients obtained from measurements under practical conditions and the corresponding theoretical values for similar flow conditions. Compared to the theoretical values, the results of the test rig are on average about 7% to 8% smaller.

Invariably there are certain aspects of the experiment where the ideal conditions stipulated in the development of correlations are difficult to achieve. The existence of pressure drops, certain unavoidable heat losses, variation of flow patterns (compared to those for which the correlations are developed) and certain assumptions used in data reduction such as negligible wall thicknesses etc contributes to differences in the experimental and theoretical values.

Conclusions The test rig was able to produce results for R134a to better than 10% accuracy referred to predictions based on the correlations. For the purpose of engineering design, accuracy of this order of magnitude is acceptable for vapour compression systems so that the experiment can be extended to other refrigerants to obtain in-tube convective heat transfer coefficients during condensation using the same test rig under practical conditions encountered in refrigeration system operation.

Table 1. Comparison of results obtained from test rig with theoretical estimates

Trial Refrigerant flow rate

Convective heat transfer coefficient (W/m2K)

kg/s x103 Experimental1 Theoretical2 1 4.225 267.7 304.5 2 4.630 301.3 327.1 3 8.712 510.0 521.0

1 - Obtained using the test rig given in Figure 1 2 - Obtained using correlation in Ref [1] and [2]


260

Acknowledgements The assistance of W.M.M.P. Abeyrathne and G.S.K. Gunasena, during initial preparation work up to commissioning of the test rig is acknowledged with thanks. Support by the staff of the Engineering Workshop in various ways, and the research grant provided by the University of Peradeniya are also acknowledged with thanks.

References Dittus, F.W. and Boelter, K.L.M. (1985) 1930,

Heat transfer in automobile radiators of the

tubular type; re-printed in Int. Comm. Heat Mass Transfer, 12, 3-22.

McLinden, M., Klein, A.S., Lemmon, E.W. and Peskin, P.A. (1998) REFPROP version 6.01, NIST, USA.

Shah, M.M. (1979) A general correlation for heat transfer during film condensation inside pipes, Int. J. Heat Mass Transfer, 22, 547-556.


261

Analysis of the Effect of Excessive Temperature and Humidity in a Production Environment

L.U. Bakmeedeniya

Department of Mechanical Engineering, Faculty of Engineering, University of Peradeniya Introduction Provision of a congenial working environment is an important matter that affects productivity of any process or service. Various measures are in place in industrial environments to maintain conditions that make the working surrounding comfortable. In the relevant standards, specifications are stipulated on acceptable levels of temperatures, humidity, noise, etc., as applied to different working environments, which are to be strictly adhered to. However, the situation in most Sri Lankan industries is far from this, owing to lapses ranging from those in planning, to the implementation and commissioning of a process. Complaints about high temperatures and humid conditions are common on production floors where the number of workers per unit area or the generation of heat/moisture is relatively high. For examples apparel industries, footwear manufacturers, catering industry/hotels etc., are common instances where one experiences such adverse working conditions. In these cases, the main problem appears to be insufficient ventilation and heat and effluent removal. These two aspects are important to maintain a balanced heat and moisture exchange process between the process or the production floor, the workers and the surroundings.

The objective of the reported study was to identify prevailing problems that affect the human comfort in the working environments and to propose remedial actions using tools of computational fluid dynamics in accordance with the relevant standards. Investigations were carried out to study the factors and analysis done with the help of available thermal comfort standards to draw conclusions from an engineering view point.

This study looks into the present state of selected industries in the above context to understand the gravity of the issue using basic heat transfer and fluid dynamic principles applied to two-dimensional flow, as a part of the research. It is expected to extend the analysis to three-dimensional flow situations using tools of computational fluid dynamics.

Methodology Two factories were selected as case studies where the occupants in the production floor experience thermal discomfort.

The geographical location and the factory layout were studied and suitable measurement grid was constructed to ensure accessibility, in order that the intended floor measurements and other readings could be obtained within an hour. At each grid point, dry and wet bulb temperatures were recorded for the different layers which were, respectively, 1 m and 2 m above the floor. The process was repeated throughout the working day (8 a.m. to 5 p.m.). Air flow velocity was also noted. The investigation procedure implemented in was repeated after one month.

Other observations made included the currently implemented solutions, inside/outside factory conditions and the environment, the number of occupants, sources of heat generation, location of fans and their effective region, blowers, diffuser fans, windows, doors and related measurements.

Analysis of observations For both case studies, relative humidity was found from psychometric chart using dry and wet bulb temperature measurements, and hourly plots of relative humidity and ambient temperature contours were individually obtained.

The behaviour of temperature and RH variation were examined on an hourly basis and compared to detect special patterns as well as repetitive behaviours. In addition, the nature of the background, such as fans, occupants, functions etc., were considered to determine their contributions to the problem and the amount of heat generation was also calculated as necessary. Considering the results the existing problems were determined.


262

Table 1. Comparison between standard values and results Value in standards Observed value

Parameter ASHRAE BOI Case 1 Case 2 Temperature / ºC 23 - 26 23 - 26 29 - 35 29 – 34 Relative humidity / % 30 - 60 30 - 60 64 - 87 62 – 83 Space per occupant / ft3 400 * 290 364

* Space per person should be more than 400 ft3 where no space over height of 14 feet (BOI, 2004; ASHRAE 55, 1981) Comparisons and discussion

Case 1 – An apparel industry situated in the Central province It was observed that the temperature contours followed a similar pattern in some regions throughout the day. Figure 1 shows such a contour in the factory during the most critical period. All the pedestal fans were placed in a way that air movement was forced towards the rear wall. But the exit door and the window areas were not enough to provide sufficient space to expel the air. As a result, air was trapped in the vicinity of the wall, which also reaps the higher temperature. The corresponding RH contours did not reflect the pattern of the temperature contours. However, the humidity range in the floor was not at the desired level.

Figure 1. Temperature contours at 2 pm (Apparel industry)

Case 2 – Footwear manufacturing factory situated in Western province Here again, the analysis of the observations (Figure 2) shows an example of a critical temperature contour in the factory, and other details show major factors, which affect the occupants’ thermal comfort. Temperature at the floor was above the accepted level, and the

relative humidity was also outside the comfort zone. In this factory, the presence of fumes from the chemicals used in the process contributes to the increase of temperature levels. There was also a high rate of heat gain from several sources. The presence of a wide monitor roof also led to the formation of eddies at the high levels leading to the stagnation of warm air in the breathing zone.

Figure 2. Temperature contours at 2 pm (Footwear manufacturing factory)

Conclusions According to the results, observations and comparisons it can be seen that the factory floor environments did not have desired values of ambient temperature, relative humidity, and also the space per person. Thus, it can be concluded that the major contributory factors for the thermal discomfort are insufficient ventilation, insufficient heat and effluent removal inside the floor owing to improper implementation of the present solutions, noxious building configuration and inadequate space per person on the floor.

References ASHRAE 55 (1981) Air quality and thermal

comfort in factory buildings, Construction Technology Update, 64.

BOI Enterprises (2004) General Guidelines for Factory Buildings

Rear wall1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.001.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.001.00

2.00

3.00

4.00


263

Limitation on Connecting Mini Hydro Power Plants to the Sri Lankan Power System

Network: A Case Study at Balangoda Grid Substation

A.I. Weerasekera1, A. Arulampalam2* and J.B. Ekanayake2 1Ceylon Electricity Board, Kandy, 2Department of Electrical and Electronic Engineering,

Faculty of Engineering, University of Peradeniya

Introduction In 2002 many mini hydro power plants were proposed to connect to the Sri Lankan power system network due to heavy shortage of electricity occurred. Today 60 mini hydro plants (Ceylon Electricity Board, 2006a)are connected to 10 grid substations and further 22 (Ceylon Electricity Board, 2006b) already issued LOI for connection. However, mini hydro plants operations are irregular in two ways. The most effected irregularity is due to faults. The MV lines are more prone for failures. Therefore the mini hydro operation got interrupted several times per months. This causes difficulties to the system operators. The most challenging cases occurred due to a line breaking during heavy loaded conditions and over voltage problems at light loaded operations.

This study is carried out in order to ascertain the implications to the power system network due to the connection of mini hydro power plants. For this study Balangoda Grid Substation is chosen as it has the maximum penetration of mini hydro plants compared to other Grid Substations. This study is based on the data collected at the mini hydro plants connected to the Balangoda Grid Substation. Several power system network loading and mini hydro generating conditions were studied. Limitations of over voltages were found and discussed when large number of mini hydros is integrated at their above 60% capacity (Ceylon Electricity Board, 2006c).

Methodology

The complete Sri Lankan power system which includes the generation & transmission system of 220/132 kV is modeled in IPSA. The 33 kV distribution system is represented by 33 kV lumped loads at each grid substation. The 33 kV feeders at Balangoda grid with mini hydro plants are modeled with mini hydro plants. Rests of the 33 KV systems are represented as loads at appropriate Grid Substations. The system was studied with and without the

embedded mini hydro generators under night peak and early morning light loading conditions. Data collection and preprocessing

The mini hydro plants connected to the Balangoda grid substation is shown in Figure 1. Distances of the plant connection from the line and rating of the each mini hydro plant are marked in this Figure.

Data collection and preprocessing The mini hydro plants connected to the Balangoda grid substation is shown in Figure 1. Distances of the plant connection from the line and rating of the each mini hydro plant are marked in this Figure 1.

The data pertaining to loads and the generation schedule at the night peak and early morning load of 10th May 2006 was fed to IPSA. The effects of connecting mini hydro plants are studied with these loading conditions. The night peak load at Balangoda Grid Substation was 24.2 MW and 9.6 MVAr and there were 11 mini hydro plants which could be connected and capable of delivering maximum amount of 30.0 MW power. The minimum load at Balangoda sub station was 6.4 MW, 2.8MVAr at early morning.

The combinations are from no contribution to full contribution from mini hydros in steps of 20% increasing in generation at night peak & minimum load condition.

Discussion With the connection of mini hydro plants even with a generation of 60% at peak, voltage of Gomala Oya, Rakwana and Wijeriya bus bars are above the limits. There are about 42 distribution sub stations fed from above and all consumers may experience over voltage. One solution to this is to transfer some loads from adjoining grids to Balangoda grid. Other wise the generation has to be curtailed. At light loading condition, the situation is more severe. Even with a generation of 40% voltage of


264

Gomala Oya, Rakwana and Wijeriya bus bars exceed the limits.

Table 1. Voltage of each bus bar

Voltage for heavy loading(peak loading) and light loading

Percentage generation of mini hydro Bus bar

0% 20% 40% 60% 80% 100% Balangoda 33Kv 0.998 1.015 1.000 1.016 1.000 1.014 0.999 1.011 0.996 1.006 0.991 1.000 Kuburuthanigala 0.986 1.015 0.991 1.018 0.993 1.018 0.994 1.018 0.993 1.015 0.991 1.011 Belihuloya 0.986 1.015 0.991 1.018 0.994 1.019 0.995 1.018 0.994 1.016 0.992 1.012 Sithagala 0.987 1.015 0.995 1.021 1.000 1.024 1.003 1.025 1.004 1.024 1.004 1.021 Alupotha 0.983 1.015 0.994 1.023 1.001 1.028 1.006 1.031 1.010 1.032 1.011 1.031 Babarathotuwa 0.975 1.015 0.992 1.029 1.005 1.039 1.016 1.048 1.024 1.054 1.030 1.058 Hapugastenna 0.974 1.015 0.991 1.029 1.006 1.041 1.017 1.050 1.026 1.057 1.033 1.061 Way Ganga 0.981 1.015 1.002 1.132 1.017 1.043 1.027 1.043 1.032 1.051 1.032 1.049 Gomala Oya 0.963 1.015 1.004 1.049 1.035 1.074 1.058 1.093 1.074 1.105 1.083 1.111 Rakwana 0.957 1.015 1.006 1.056 1.043 1.084 1.073 1.112 1.094 1.130 1.109 1.141 Wijeriya 0.955 1.015 1.007 1.059 1.048 1.098 1.080 1.121 1.105 1.141 1.122 1.155

Table 2. Line flows and line losses

Fault level MVA Fault level MVA Bus bar Without

mini hydros With mini

hydros Bus bar Without mini

hydros With mini

hydros Balangoda 33Kv 1092.754 1266.835 Hapugastenna 108.703 311.607 Kuburuthanigala 237.011 332.148 Way Ganga 161.137 367.976 Belihuloya 211.293 290.604 Gomala Oya 75.772 219.822 Sithagala 255.557 366.773 Rakwana 59.127 193.199 Alupotha 194.951 321.661 Wijeriya 52.796 235.994 Babarathotuwa 116.764 286.510

Table 3. Fault level

Fault level MVA Fault level MVA Bus bar Without

mini hydros With mini

hydros Bus bar Without mini

hydros With mini

hydros Balangoda 33Kv 1092.754 1266.835 Hapugastenna 108.703 311.607 Kuburuthanigala 237.011 332.148 Way Ganga 161.137 367.976 Belihuloya 211.293 290.604 Gomala Oya 75.772 219.822 Sithagala 255.557 366.773 Rakwana 59.127 193.199 Alupotha 194.951 321.661 Wijeriya 52.796 235.994 Babarathotuwa 116.764 286.510

Fault level of Balangoda grid is increased by 16% by connecting the mini hydro plants. Breakers at the grid at 33kV level have a short circuit capacity of 1450 MVA. Hence at this moment it is not a problem. If any other plants to be connected the switch gear of Balangoda grid sub has to be changed.

The line losses due to the connection of the mini hydro plants have been increase by 3 MW. This is very significant as it was 0.14 MW with out mini hydros. The line losses of

132 kV side has increased by 1.22 MW by connecting the mini hydro plants. It is 37% increase over the losses without mini hydro plants.

Conclusions At Balangoda grid, mini hydro plants penetration is studied. This has shown that the voltages at the mini hydro plants terminals have already exceeds the limits with above 60% injection at night peak loading conditions.


265

Further over voltages occurred in several points at light loading condition. This has also increased the fault level at the grid substation by 16%. Therefore this study concludes that for proper utilization of mini hydro plants, a voltage control mechanism must be adopted at the grid.

References Ceylon Electricity Board (2006a) Statistical

Digest 2006, Statistical Unit, Commercial & Corporate Branch.

Ceylon Electricity Board (2006b) Medium Voltage System Planning Report 2006, Sabaragamuwa Province.

Ceylon Electricity Board (2006c) Monthly Review Report - May 2006, System Control Branch.

Figure 1. Mini hydro plants connected to Balangoda grid substation


266

Microgrid Operations: Case Study at Nilambe Mini Hydro Grid

D.N. Navaratne1, J.B. Ekanayake2 and A. Arulampalam2* 1Asset Management Hydro Electrical, Ceylon Electricity Board, Kandy

2Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Peradeniya

Introduction Embedded generation technologies are proved by researchers as one of the solution to satisfy the increasing electricity demand while optimizing the existing network (Jenkins, 2000). In Europe micro grid technology also potentially studied to supply green electricity to most important industries (Lasseter, 2002; Arulampalam et al., 2004). However, challenges are being made on keeping the micro grid running when the main grid was disconnected due to a fault and smooth reconnection of micro grid when fault is cleared. The objective of this study is to find out the possibility of synchronizing a microgrid to the main grid at grid connection point, when it is disconnected due to a fault. In this study, Nilambe 1.6 MW mini hydro generator with its surrounding grid shown in Figure 1 was taken as micro grid. It was studied whether the embedded generator could be kept running while feeding surrounding loads during a Grid failure. The frequency and voltage maintaining capability of this generator was also checked with shedding excess loads when it was islanded. Finally automated synchronizing control of this micro grid was studied once the grid was restored. Methodology The micro grid with embedded generator was modeled using EMTDC/PSCAD simulation package. All the loads in the medium voltage network lumped into two loads one representing the non frequency sensitive loads and other representing frequency sensitive loads. Initially steady state stability of the micro grid, connected to the main grid, was studied. Automatic Voltage Regulator (AVR) operation and governor controller operations were checked in islanded operation. Finally resynchronization and automatic grid connection was checked, when grid was resorted. Data of generator, transformer and feeder is annexed.

A simplified model of the system is shown in Figures 2. The transformer and the series impedance of the line are lumped into one series impedance of (0.354+j27.626) Ω. AVR and governor controls together with synchronization control are shown in Figures 3 and 4. The AVR consists of a PI regulator with an output derivative feedback function to represent the practical AVR response. The governor consists of a PI regulator with the

permanent droop feedback. Data collection and modeling

B-

D +

F

-G

+ field1

1 + 0.5s

0.10.1s

1 +0.1 s

I

P=101

1 + 0.5sReference

Micro grid voltageB+

F-

Grid voltageI=0.5

P=4

Voltage feedback I=0.2Excitor

Synchronization input

Non linear GainBreak point =0.1 pu

Limiter

P+I of AVR

Figure 2. Simulation model of the AVR

Figure 3. Simulation model of the governor

G

MAIN GRID

LOADLOAD

LOAD Tran

smis

sion

M icro grid

Synchronizer

LOAD

GovernorAVR

PT1

PT2

Figure 1. Micro grid at Nilambe


267

Figure 4. Simulation model of the studied system

In simulation, the stability of the generator in islanded mode, just after tripping of the breaker at the grid connection point, was studied (generator was loaded to ≈75% of its capacity). The results are shown in Figure 5a. Similarly the stability of the generator just after shedding of lumped frequency depended sensitive loads (0.544 MW) was studied and results are shown in Figure 5b. The voltage variations in the generator bus and the micro grid point of connection to grid were tabulated in Table 1. Simulation results

0.0 5.0 10.0 15.0 20.0

0.40 0.60 0.80 1.00 1.20

pu

Excitation Voltage

0.950

1.000

1.050

pu

Generator bus voltage

0.960 0.990 1.020

pu

line end voltage

1.000 1.020 1.040

pu

Speed

0 500.60 0.70 0.80

pu

turbine

Here the generator governor setter and the AVR setter were kept at 1.08 pu and 1.01 pu respectively. The stability of the generator during synchronization to the grid, when grid voltage was initially at 1.06 pu and frequency was 1.1 pu, was tested and results are shown in Figure 6 and the voltage variations are tabulated in Table 2. The synchronizing parameters are selected as (i) maximum frequency deviation is ± 150 mHz and (ii) maximum voltage deviation is ±10%.

0.0 5.0 10.0 15.0 20.0

0.40 0.60 0.80 1.00 1.20

pu

Excitation Voltage

0.950

1.000

1.050

pu

Generator bus voltage

0.960 0.990 1.020

pu

line end voltage

1.020 1.030 1.040 1.050

pu

Speed

0.40

0.50

0.60

pu

turbine

Figure 5a. Results at islanded operation Figure 5b. Results at shedding loads


268

Table 1. Transient study results at islanded

and load shedding operations Grid failure Excessive load

shedding

Over shoot

Under shoot

Over shoot

Under shoot

Generator bus voltage/pu 1.025 0.983 1.026 1,001

Grid point voltage/pu 1.003 0.966 1.004 0.979

Generator Speed/pu 1.035 1.049

Guide vane opening /pu 0.556 0.378

Table 2. Transient study results at

synchronizing process

Pre

synchronization

Over shoot

Under shoot

Steady state

Generator bus voltage/pu 1.01 1.04 1.03

Grid point voltage/pu 0.991 1.021 1.02

Generator Speed/pu 1.03 1.11 1.09 1.098

Guide vane opening /pu 0.41 0.851 0.346 0.438

Discussion The AVR and governor responses have proven that it can maintain the micro grid stability after a grid failure with excessive load rejection. The maximum generator bus voltage overshoot is 2.6% and maximum grid point overshoot is 0.4% for the grid failure. The maximum frequency overshoot is 4.9%. The maximum bus voltage overshoot during the synchronization is 3%. The speed overshoot is 8%. Even though these overshoots are little higher than the expected values, the system was stabilized within few seconds.

Conclusions This study confirms that synchronization of the Nilambe generator with the micro grid consisting of local loads after shedding the excessive load is possible. The proposed AVR and governor control together with automatic synchronizer has shown very good performance within allowable responses limits. Therefore this can be taken as a preliminary studied model in for developing micro grid technology to the Sri Lankan power system.

A commercially available synchronizer can be configured and used with transmitters and receivers for this purpose of remote sensing and synchronizing.

References Arulampalam, A., Barnes, M., Engler, A.,

Goodwin, A. and Jenkins, N. (2004) Control of power electronic interfaces in distributed generation microgrids, International Journal of Electronics, 91(9), 503-523.

Jenkins, N., Allan, R., Crossley, P., Kirschen, D. and Strbac, G. (2000) Embedded Generation, IEE power and energy series 31, 2000, ISBN 0853967748

Lasseter, R.H. (2002) MicroGrids, IEEE Power Engineering Society Winter Meeting, Volume 1, 305-308.

Appendixes Generator data: 3MVA, 6.9kV, 0.85 p.f., Xd=1.014 pu, Xd'=0.314 pu, Td0'=6.55 sec, Xd"=0.28 pu, Tdo"=0.039 sec, Xq=0.77 pu, Xq"=0.375 pu, Tqo"=0.071 sec, Inertia 2 sec. Line data: 33kV tower line of "Links" conductor line length -2km, Positive sequence resistance - 0.177ohms/km, reactance - 0.313 ohms/km, Zero sequence resistance - 0.326 ohms/km, reactance - 1.588 ohms/km Transformer data: Capacity - 4MVA, Voltage ratio - 6.9kV/33kV, Impedance voltage - 10%

Figure 6. Simulation results at synchronizing process


269

Power Factor Correction and Harmonics Effect to an Industrial Load

S.K. Abeygunawardane, K.I.R. Prasanna, A. Arulampalam* and J.B. Ekanayake


Introduction In the proposed long term development plan, the Government of Sri Lanka has targeted to establish many new industries. To achieve this, electricity generation should be increased. Since we can not expect major power additions to the national system until proposed power projects are completed, effective energy management is important. For higher utilization of power, power factor has to be maintained at closer to unity at every usage point of electricity (Wang and Cheng, 2004).

At low power factor, transmission lines carry both active power and reactive power and it increases line current and line losses. On the other hand CEB charges for high reactive power consumption through kVA demand. Therefore power factor correction is beneficial to the supplier in terms of line loss and also to the consumer in terms of bill payment. However, the harmonic loads make sever effects to the power factor correction capacitor banks (Gajanayake et al., 2005; Shwedhi and Sultan, 2000; Wagner et al., 1993). It has been noted that several industries are suffering from burning capacitors.

This paper presents the power factor correction method for inductive loads using capacitor banks, and harmonic loads’ effect on the power factor correction capacitors. All effects are resonated with the simulation and experimental results. To control harmonics in industries passive filters, active filters or combined systems can be used (Peng, 1990).

This paper proposes the Sri Lankan industries to use harmonic filters in order to protect capacitor banks from harmonics.

Methodology An inductive load supplied from three phase was modeled in EMTDC/PSCAD computer simulation package. This has also been made in laboratory scale experimental setup. Power factor correction was carried out using a capacitor bank. A three phase rectifier load was used to produce the harmonics and its effects

were checked using oscilloscope. The laboratory scale experimental setup is shown in Figure 1. The corresponding simplified electrical circuit diagram is shown in Figure 2.

As shown in Figure 2, a three phase induction motor and a delta connected three phase inductor bank were connected to a three phase supply. This is to represent industrial loads, mostly which are inductive in nature. Then current and voltage waveforms were observed using the oscilloscope. Assume the lagging power factor of the system is cosϕ1.

Figure 1. Photograph of the experimental setup

Figure 2. Electrical circuit diagram of the studied system

Theoretically, a capacitor of Q kVAr can be used to compensate same inductive power to produce cosϕ = 1. But it is not a common practice as it is not much cost effective and may result in overcompensation due to load changes. Therefore it compensates to get a specified value; cos ϕ2, to which the power factor should be corrected.

Three phase rectifier loads

Power factor correction capacitors

Inductive Three phase induction


270

Next, a three phase capacitor bank was connected in parallel to loads to implement power factor correction, and waveforms were observed.

Figure 3. Power factor correction triangle P = Active power S1, Q1 = Uncompensated apparent power and reactive power

S2, Q2 = Apparent power and reactive power after power factor correction QN = Reactive power compensated by the capacitor

A three phase rectifier which generates harmonics was connected in parallel to loads. The effect of the presence of harmonics in the system to the capacitor bank was also observed. Finally, a simulation study was carried out for the above circuit and experimental results were compared with the simulation results.

Figure 4. Waveform of the supply voltage and load current

Figure 5. Waveform of the supply voltage and supply current

Figure 6. Waveform of the supply voltage and capacitor current

Figure 7. Waveforms of the capacitor current and harmonic load current with supply voltage

0.020 0.030 0.040 0.050 0.060

-400 -300 -200 -100

0 100 200 300 400

Volt,

Am

p

Vsupply ILoad*5

0.020 0.030 0.040 0.050 0.060

-400 -300 -200 -100

0 100 200 300 400

Volt,

Am

p

Vsupply Isupply*5

0.020 0.030 0.040 0.050 0.060

-400 -300 -200 -100

0 100 200 300 400

Volt,

Am

p

Vsupply Icapacitor*5

P ϕ2

S2 Q1

QN

Q2

S1

ϕ1


271

Results The experimental and simulation results are shown in Figures 4, 5, 6 and 7. Experimental results are shown in left side while the simulation results are on the right side.

Discussion Power factor correction capacitor bank can be used for power factor improvement in industries, which are normally having highly inductive loads. When the power factor correction capacitor bank is connected to the system with inductive loads total current drawn from the supply is reduced as shown in Figures 4 and 5. This confirms that the supplier current is reduced and thus the maximum kVA demand also reduced.

However, the capacitor bank introduces more harmonics to the system. This can be observed from the load and supply current waveforms shown in Figures 4 and 5. This is mainly because of the already existing harmonics in the supply voltage. This can be further confirm when compare the capacitor current in simulation and experimental waveforms shown in Figure 5. Here the supply voltage had the harmonics while simulation the harmonics was not there.

When a rectifier harmonic load is added to the system, it injects more harmonic current to the grid. In this case according to the characteristics of the power factor correction capacitors, they show low impedance to the harmonic current. Therefore the capacitor current waveform in Figure 7 is increased. However, in this experimental set up a small harmonic load was used and also the supply voltage already consisted harmonics due to neighborhood harmonic loads. Therefore significant increment in the harmonic current could not be seen when harmonic load was added. As a result it can be concluded that the harmonic current increased in the power factor correction capacitors when harmonic loads are added to the grid in neighborhood areas.

Recently many industries already placed several variable speed drives for energy saving purpose. Most of these are heavy harmonic loads. Therefore the harmonic current drawn in to the power factor correction capacitors will also be increased. An industry must consider about its already installed power factor correction capacitor, because this will heat the

capacitor and finally the capacitor will get damage.

Conclusions This study clearly explains the benefits of the putting the power factor correction to the industries and the CEB suppliers. Also it proves that the harmonic current will increase with harmonic load additions such as variable speed drives. Therefore it has given clear explanation to the capacitor heating in industries when they installed more harmonic loads after installing the power factor capacitors. Therefore proper monitoring of the harmonic content is important for proper operation of the power factor correction capacitor. To control harmonics in industries, a harmonic filter can be used. In the future we plan to study the design of filters and practically implement a filter for harmonic control.

Acknowledgments The authors are acknowledging Mr. M.G.H Ranatunga, Mr. R.S. Abeythunga, Mr. T.C. Dissanayake and Miss. L. Karunanayake for their support in arranging the set up.

References Gajanayake, C.J., Ramtharan, G.,

Samaraweera, G.K., Atputharajah, A. and Ekanayake, J.B. (2005) A survey of harmonic current at several industries in Sri Lanka, Journal of the National Science Foundation, Sri Lanka, 33(3), 205 – 217.

Peng, F., Akagi, H. and Nabae, A. (1990) A new approach to harmonic compensation in power system- A combined system of series active and shunt passive filters, Electrical Engineering in Japan, 110(5), 88-98.

Shwedhi, M.H. and Sultan M.R. (2000) Power factor correction capacitors; essentials and cautions, Power Engineering Society Summer Meeting, IEEE 3, 1317 – 1322.

Wagner, V.E., Balda, J.C., Griffith, D.C., McEachern, A., Barnes, T.M., Hartmann, D.P., Phileggi, D.J., Emannuel, A.E., Horton, W.F., Reid, W.E., Ferraro, R.J. and Jewell, W.T. (1993) Effects of harmonics on equipment, Power Delivery, IEEE Transactions, 8(2), 672-680.

Wang, D.H. and Cheng, K.W.E. (2004) General discussion on energy saving, First International Conference on Power Electronics Systems and Applications, 298 – 303.


272

Modelling Sri Lankan Power System to Study the Effect on Dynamic Stability with Large Scale Wind Power Integration

R.H.B. Ekanayake1, A. Arulampalam2* and J.B. Ekanayake2 1Ceylon Electricity Board, Kandy

2Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Peradeniya

Introduction To meet the increasing demand for electrical energy, the estimated need of new generating capacity to the Sri Lankan power system is over 4400 MW in next 15 years (Ceylon Electricity Board, 2003; Ceylon Electricity Board, 2005). Studies have revealed that wind is the most promising option of the available renewable sources for grid connected power generation in Sri Lanka other than the conventional larger generating stations. Wind energy resource assessment study carried out in 2002 has confirmed the availability of 20,000 MW of wind resources in north-western coastal region from Kalpitiya Peninsular to Mannar Island, Jafna Peninsular and the Central Highlands.

However not enough studies are available to assess the transmission grid accessibility of these wind resources. And also no system studies are carried out on routine basis for transmission connection proposal for non-dispatchable power including the large scale integration of wind power. However the studies associated with large scale integration of wind power are less complication than that of the distributed power generation. Yet dynamic stability is the concerning issue due to the intermittency of the wind power availability and also due to the limitations of supporting the fault current by wind generators.

Methodology The Sri Lankan transmission system is initially modelled using IPSA software, with data sufficient for steady state analysis. The best option would be to build the model from the beginning using the database, which will accommodate the easy maneuverability of the model for different applications and users. It also helps the gradual upgrading of the database with real data when available. The model thus developed was run for steady state analysis and the computed values were compared with actual measured values for different loading conditions.

In the next step, the generator data required for transient studies was inserted in to the database. In first attempt, no typical data was used in place of missing data. This allows the system to run on IPSA default values. Dynamic stability of the system was then studied to demonstrate the stability model of the IPSA. Then in second attempt, the default damping factor (which was zero in IPSA) was slightly adjusted together with minimum required transient data using typical values. This was done for machines, which were not had sufficient data. These values were stored in a different database thus leaving the database with real data untouched.

The following Stability criterion is used. The system shall remain stable during and after a system disturbance for three phase faults at any O/H line cleared by the protection with successful and unsuccessful auto re-closing including a possible loss of generation and load transformer. Few marginal dynamic stability cases were identified for this study through the experience on the recent faults events in the CEB system and by considering the three phase fault levels at all the bus bars.

In present Sri Lankan power system stability issues are more vulnerable during the periods of more concentrated heavy hydro generation. These periods are generally occurred in July-August and November-December, for normally anticipated weather patterns. Therefore within this paper the stability analysis was limited to system peak loading occurred at 19:30 hrs on 7th August 2006. The considered peak had 50% concentrated hydro 30% concentrated thermal and 20% dispersed mixed generation [Ceylon Electricity Board, 2006]. All loads were modelled as fixed load as it represent worst case. In other words the motor loads generally supports towards greater stability than the fixed loads.

Finally, the impact on the dynamic stability of the Sri Lankan power system on integrating


273

moderately large wind power to the system at identified Grids, were studied for the selected marginal stability cases. Study within this paper was limited to 100 MW wind integration at Puttlam Grid Substation for a night peak loading condition.

Results Following bus bars are more vulnerable for dynamic instability when three phase fault occurs at the line with heaviest current, closest to the bus bar. Measured and calculated voltages and load flow are listed in the Tables 1, 2 and 3 (Ceylon Electricity Board, 2006).

Table 1. Comparison of voltage results

Bus Bar Voltage

measured (kV)

Voltage calculated

(kV) Kotmale_220 225.0 223.3 Victoria_220 230.0 226.2 Kalnya_132 130.0 129.4 Fort_132 128.0 129.2 SapGS_132 132.0 129.8 LaxNew_132 132.0 133.9

Table 2. High fault level 220 kV bus bars & heavily loaded lines with load flow comparison

Bus Bar Symmetri. fault level (pu MVA)

Heavily loaded line /

Generator

Calcula. load

(MW)

Measur.load

(MW) Biygma_220 46.601 Kotmale_220 141.83 140 Kps_220 44.228 Kps_CCG 104.99 105 Kotmale_220 40.948 Biygma_220 141.83 140 Panni_220 39.409 Biygma_220 58.63 60 Ktgoda_220 37.226 Biygma_220 81.33 80 Victoria_220 36.167 Kotmale_220 91.25 90

Table 3. High fault level 132 kV bus bars & heavily loaded lines with load flow comparison

Bus Bar Symmetric. fault level (pu MVA)

Heavily loaded line /

generator

Calcula load

(MW)

Measur. load

(MW) Kalnya_132 40.845 SapGS_132 49.17 50 Fort_132 40.518 Kps_132 69.88 70 SapGS_132 37.822 Biygma_132 69.78 70 Polpitiya_132 37.450 Kotmale_132 61.76 60 LaxNew_132 37.025 Polpitiya_132 50.50 50 Kollon_132 44.173 Mrdna_132 63.57 65

The stability studies were done on the modelled Sri Lankan power system network. This was

done for successful three phase re-closure after 300 ms and also for unsuccessful re-closure. The fault clearing time was assumed as 100 ms. Four cases were studied in simulation and their waveforms are shown in Figure 1, 2, 3 and 4.

Case 1: Fault at Kps_220 bus bar cleared through bus bar protection

Figure 1(a) Bus voltages Figure 1(b) SM rotor angle

In Figure 1(a), around 165 MW generation is loss from the system when clearing the Kps 220 bus bar for a bus bar fault. In Figure 1(b), KGT1 is a machine closer to the affected bus bar and Victoriya G1 is a machine far away to the affected bus bar. Both machines are remaining in stability after the bus bar fault.

Case 2: Double Faults on Biyagama Kotmale 220 kV Lines at Biyagama end

Figure 2(a) with re-closing Figure 2(b) without re-closing

Biyagma 220 and Kotmale 220 are buses with heavy fault level and experiences system collapse during double faults under certain loading conditions. Kps CCS closer to the affected bus is critically stable on unsuccessful re-closing.

This demonstrates the modelling capability of IPSA to study dynamic stability issues. It was checked with 400 ms clearing time and with longer clearing time without re-closing it shows the reaching critical stability on the Kotmale machine closer to the fault.


274

Case 3: ApuraNew line at Kotmale without re-closing 300 ms clearing delay

Figure 3(a). No wind Figure 3(b). With wind

Discussion The database approach is the most appropriate for power system model development in IPSA. The initial steady state and security analysis was done through the partly populated database. Studying of the large power system was done in highly structured manner in the order of steady state load flow analysis, rate exception handling and contingency analysis. The dynamic stability of power system was studied only after solving and / or identifying the unsolved issues in the order mentioned. In the process, the model is validated by comparing to the measured load data and also to the known instability issues. Finally the model was used to forecast the system stability for large scale wind integration at the most promising site at Puttlam, where the base load coal power plant is also anticipated. In large scale wind integration of wind, it is assumed

that the wind is connected through a representative synchronous generator. During a disturbance wind generation will back off from the system without supporting the fault current, in worst case scenario.

Conclusions Calculated load data through steady state load flow analysis is tallied with measured data. Instabilities shown in the system for unsuccessful auto re-closing at Biyagama Kotmale 220 kV double circuits for simultaneous faults, is a known issue in the system, which was instrumental on blackout of the system as well. Also few selected marginal cases of instability were not worsened due to the introduction of 100 MW wind at Puttlam. This was evident from the case of three phase fault on ApuraNew line at Kotmale bus bar without re-closing and 300 ms clearing delay. Therefore the developed IPSA model of the Sri Lankan power system can be used for further studies of the system.

References Ceylon Electricity Board (2003) Long Term

Transmission Development Studies 2004 – 2013.

Ceylon Electricity Board (2005) Long Term Generation Expansion Plan 2006 – 2020.

Ceylon Electricity Board (2006) System Control & Operations – Monthly Review Reports.

FACULTY OF SCIENCE

and

POSTGRADUATE INSTITUTE OF SCIENCE


275

Structural Studies of Plant Pigments Used in Dye Sensitized Solar Cells

F.M. Hussain1, V. Sivakumar1* and K. Tennakone2 1Department of Physics, Faculty of Science, University of Peradeniya

2Institute of Fundamental Studies, Hanthana Road, Kandy Introduction In the modern world, there exists a high demand for pure and clean sources of energy. Solar cells can be identified as a good candidate for this category. The use of natural dyes as sensitizers for solar cells is justified by the need to produce energy which is at the same time reliable, safe and eco-friendly (O’Regan and Gratzel, 1991). Generally, anthocyanins are considered as suitable natural pigments to be used in dye sensitized solar cells.

Anthocyanins are water soluble pigments which can be found in most land plants with a few exceptions such as cacti and the group containing the beet. These pigments reflect the red to blue range of the visible spectrum. Therefore, they are responsible for the red, purple and blue colours in many fruits, vegetables, grains and flowers.

Anthocyanins can be divided into sugar free anthocyanin aglycons and anthocyanin glycosides with sugar moieties attached. There are many types of anthocyanins present in nature which are named according to the types and positions of functional groups attached to the central core of the anthocyanin molecule. The most abundant anthocyanin in nature is cyanin.

The use of anthocyanins in dye sensitized solar cells can be justified, as the structure of the molecule suggests possible anchorage to titanium dioxide.

This paper presents the structural study of natural pigments used in dye sensitized solar cells with the aid of Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and theoretical calculations of vibrational modes using hybrid Hartree-Fock/density functional theory (HF/DFT).

Materials and methods Pigments were extracted from three sources namely purple yam, pomegranate seeds and spinach seeds. The pigment from purple yam

was extracted in a 50% methanol solution, while pigments from pomegranate and spinach were extracted by squeezing the seed coats and filtering the juice. Further, a purification method was followed in order to isolate anthocyanins from any impurities, which may have been present in the extracted pigment. UV-Visible spectroscopy was used to identify the presence of anthocyanins in all three pigment samples.

In order to analyze the pigment samples using DRIFT spectroscopy, they were converted from liquid form to powder form by mixing with potassium bromide (KBr) powder followed by drying. Spectra corresponding to the pigment alone and the pigment adsorbed onto TiO2 were separately obtained for each sample. Hybrid HF/DFT calculations were done using the B3LYP method within Gaussian 03 to quantify the vibrational properties of the pure pigment and the pigment adsorbed to TiO2.

Results The cyanidin models in Figure 1 were used in the theoretical calculations carried out. Model A corresponds to the pure cyanidin molecule, while model B is the molecule after binding with Ti. In Figures 2, 3 and 4, experimental and calculated spectra corresponding to each sample studied were compared.

The encircled area in the experimental spectra in Figure 2 shows the disappearance of the band around 1077 cm-1, which corresponds to the free OH bending mode. Similarly, the encircled area of the calculated spectra in Figure 2 also shows the disappearance of the band around 1100 cm-1.

The encircled area of the experimental spectra in Figure 3 shows the downward shift of the band around 1400 cm-1, which corresponds to the OH bending and C-C stretching mode. Similarly, the encircled area in the calculated spectra in Figure 3 also shows the clear downward shift of the band around 1400 cm-1 after adsorption onto TiO2.


276

Figure 1. Cyanidin models used in vibrational mode calculations

Figure 2. Experimental DRIFT spectra for spinach (left) and calculated spectra for the cyanidin

models (right)

Figure 3. Experimental DRIFT spectra for purple yam (left) and calculated spectra for the

cyanidin models (right)

The encircled area of the experimental spectra in Figure 4 shows the downward shift of the band around 1700 cm-1, which mainly corresponds to the C=O stretching mode, after adsorption onto TiO2. The encircled area of the calculated spectra in Figure 4 also shows the downward shift of the band around 1700 cm-1 after adsorption onto TiO2.

Conclusions From both experimental and theoretical results, it can be concluded that:

1. Experimental results for all the pigments well agree with the theoretical results calculated for the cyanidin model.


277

Figure 4. Experimental DRIFT spectra for pomegranate (left) and calculated spectra for the

cyanidin models (right)

2. A band corresponding to the free OH bending mode around 1100 cm-1

disappears after adsorption to TiO2. This proves that the anchoring to Ti is through hydroxyl groups of cyanidin.

3. The band corresponding to the OH bending and C-C stretching around 1400 cm-1 shifts downwards upon adsorption to Ti. Similarly, another band around 1700 cm-1 mainly corresponding to C=O and C=C stretching modes splits upon adsorption. These shifts and splits are mainly due to the change in electron

density of the cyanidin molecule upon adsorption to Ti.

Acknowledgements Financial assistance by the University of Peradeniya (Research Grant RG/2006/44/S) is acknowledged.

References O’Regan, B. and Gratzel, M. (1991) A low-

cost, high efficiency solar cell based on dye-sensitized colloidal TiO2 films, Nature, 353, 737.


278

Layers – An Abstract Extension of Fields for Higher Dimensions

H.M. Nasir* and M.S.M. Waasim

Department of Mathematics, Faculty of Science, University of Peradeniya Introduction We propose a new abstract algebraic system, which extends the notion of real and complex number systems. With the relaxation of some field axioms, we are able to extend the complex number system to higher dimensions. This extension gives ways to analyze many problems in physics and engineering. The study was motivated by considering the general solution of the Laplace equation. In a three dimensional domain, the Laplace

equation is given by .02

2

2

2

2

2

=∂∂

+∂∂

+∂∂

=Δzu

yu

xuu

Separation of variables )()()( zZyYxXu =

yields .0"""=++

ZZ

YY

XX Since the terms in this

equation are dependent on only one variable, each term equals to a constant, say,

22 "," bYYa

XX

−=−= and ," 2cZZ

−= where

cba ,, satisfy ,0222 =++ cba and the solutions are given by czbyaxeu ++= . In fact, one may easily see that for any function )(wf with

,0)('' ≠wf the expression )( czbyaxfu ++= is a solution. We seek a

space in which the constants might be with the conditions that cba ,, are linearly independent and quadratic dependent. In fact, there are no constants in the real and/or complex fields that satisfy the above two properties, because any three member in these fields are linearly dependent. This observation demands us to consider a number system, which is other than the real and complex fields. This motivation and application was presented in IWAMCS07 (Nasir et al., 2007).

Literature review The theory of numbers has always been a quite fascinating and rich subject and seems to stem from ancient Greece. Complex number theory

is by itself a nice achievement in this endeavor. Extensions of complex numbers have been an active subject in the 19th century by many prominent mathematicians such as Hurwitz, Clifford, Graves, Grassman and Hamilton. The notable extensions in this period are the Clifford and Grassman algebras that have applications in physics. Hamilton’s quaternion and the subsequent discovery of octonion were considered big achievements in the search of higher dimensional fields.

But all these extensions lacked one or more important properties of multiplication, namely commutative and associative.

Recently, Fleury et al., (1993) have extended the complex number theory with these two properties intact to higher dimensional vector spaces and called them multicomplex numbers. These multicomplex numbers mostly behave like complex numbers and most of the algebraic and analytic properties were shown by Fleury et al., (1995). Our definition is more general and includes the multicomplex number system as a simple example.

A New Abstract Set

We define a new abstract space as follows: Definition 1: Let ...,,...,,, 210 nVVVV be vector spaces over the real field R with

nn dV =dim , RV =0 and U∞

==

0n nVV . Then,

,, nVuVvu ∈⇒∈ mVv ∈ for some nm, . Define multiplication of vectors in V satisfying the following four axioms: L1: .VVuv nm ⊆∈ + L2: Vvuvuuv ∈∀= ,, . L3: Vwvuvwuwuv ∈∀= ,,),()( . L4: ,,1 Vuuu ∈∀= where 01 V∈ . In this new construction, we relax the existence of multiplicative inverse. Addition between elements of different vector spaces is used for symbolic purpose only. We call the abstract


279

space ‘Layer’; each vector space VVn ⊆ a layer of mode n; the space 0V the ‘unit layer’ which is R; the space 1V the ‘base layer’ and the dimension of 1V the ‘base dimension’. All the zero vectors mm V∈0 are commonly called zero and are denoted by 0. Example 1: Let 2D be the set defined by

,,0; 222 RyxbabyaxD ∈=++= and

| 21 DzzaV n

n ∈= − for n>0 with RV =0 .

Let U∞

==

0n nVV . Then, V forms a Layer with

the usual multiplication. Here, 2dim =mV for each m>0 and the Layer becomes a field isomorphic to the complex field. Example 2: Let .deg;)( npxpV nnn ≤=

Define multiplication on U∞

==

0n nVV

mmnnmn VpVpxqxppq ∈∈= ,),()( . Here, we have mn VV ⊂ for mn < and

.1deg += nVn Example 3: Let np be polynomials of degree less than or equal to n and define

,,;),( 111 −−− ∈∈== nnnnnnn VpVpppPW where nV are vector spaces of polynomials defined

in Example 2 and let .0U

∞

==

n nWW Define a

multiplication

.),)1((

),).(,(

11112

11

mnmnmnmn

mmnn

qpqpqpxqp

qqppPQ

−−−−

−−

++−=

=

Here, .12dim += mWm

Main Results

Here we list the main theorems for this paper. Theorem 1: Let V be a Layer with the base layer 1V and ,,, 3211 naaaaB L= be a basis for 1V . Then, for each layer mV , a basis can be expressed in terms of the powers of total degree m of basis vectors from 1B .

Definition: A Layer is called a Harmonic Layer if there is a basis ,,, 3211 naaaaB L=

for the base layer 1V such that 01

2 =∑ =

n

i ia .

Theorem 2: Let V be a harmonic Layer with base ,,1 cbaB = . Then, the set of 2m+1 monomials of degree m given by

,,,

;,,,,121

221

cbbcacabbabaa

mmm

mmmm

−−−

−−

L

L

is a maximal linearly independent set in mV and hence .12dim += mVm

An application One of the interesting applications of Layer concept is the representation of functions in more than two variables by harmonic functions (Nasir, 2007). Harmonics are solutions of the Laplace equation. Try lczbyaxu )( ++= for a solution, where a, b, c are independent constants. Then a, b, c satisfy .0222 =++ cba Hence, we see that the solutions of the Laplace equations can be expressed as powers of the vectors from the base layer of some Layer V . Expanding the power representation using the constraint and by Theorem 2, we see that each term in the expansion is a solution of the Laplace equation. For example, with ,2=l we have,

).2()2()2()()(

222

)(

222222

222222

22

xzacyzbcxyabzybzxaacxzbcyzabxy

zcybxa

czbyaxu

+++−+−=

+++++=

++=

Since, by Theorem 2, the monomial set ,,;,, 22 acbcabbaba is a basis for the layer

2V . Applying Laplacian on 2u , we deduce that the functions

xzyzxyzyzx 2,2,2,, 2222 −− are all solutions of the Laplacian equation. This is true for arbitrary power l as well.

Conclusions We have constructed an abstract extension of complex numbers which has a multiplication


280

with four properties. We called the abstract set ‘Layer’ and showed that the real and complex fields are trivial and simple cases of a Layer called harmonic Layer. We presented an application of our abstract setting in the construction of harmonic functions. The definition is restricted to be primitive to meet our immediate needs, but could be refined with further properties. Further research is needed to find other properties to be satisfied by the Layers.

Acknowledgements This research was partially supported by the Peradeniya University research grant RG/2006/48/S.

References Fleury, N., Detrauberg, M.R. and Yamaleev,

R.M. (1993) Commutative extended complex numbers and connected

trigonometry, Journal of Mathematical Analysis and Applications, 181(2), 431-457.

Fleury, N., Detrauberg, M.R. and Yamaleev R.M. (1995) Extended complex number analysis and conformal-like transformations, Journal of Mathematical Analysis and Applications, 191(1), 118-136.

Nasir, H.M. (2007) Spherical harmonics transform in a non-polar coordinate system and application to Fourier series in 2-Sphere, Mathematical Methods in the Applied Sciences, John-Wiley, 30(14), 1843-1854.

Nasir, H.M., Faham, M.A.A.M. and Waasim, M.S.M. (2007) Power representation of spherical harmonics and fast discrete spherical transform on cubed sphere, International Workshop on Applied Mathematics and Computational Science (IWAMCS07) Sept. 25-29, 2007, The University of Electro-Communications, Tokyo, Japan.


281

Deriving Shrunken Estimators for the Variance in One-Parameter Natural Exponential Families

A. Laheetharan1 and P. Wijekoon2* 1Department of Mathematics & Statistics, Faculty of Science, University of Jaffna

2Department of Statistics & Computer Science, Faculty of Science, University of Peradeniya Introduction Exponential family of distributions is an important class of distributions in statistics. Estimation of mean and variance of the distributions of this class is one of the problems that the researchers are involved. Several Statisticians have considered the estimation of mean in one parameter exponential families when coefficient of variation is known, and an improved method in this regard was given by Wencheko and Wijekoon (2005). Morris (1982) and Letac and Mora (1990) showed that the variance of some basic types of distributions belong to the one parameter exponential family is a polynomial function of the mean μ with degree less than or equal to 3. The objective of this study is to derive an optimal shrunken estimator for these variance functions.

One parameter exponential family and variance functions Consider the random vector X = (X1, . . . , Xn) whose probability density function is a function of the parameter θ, where θ ∈ Θ for some interval Θ ⊆ ℜ. Then the family of distributions of a model Pθ : θ ∈ Θ is said to be a one parameter exponential family, if there exists real valued functions, )(θη , )(θB , )(xT and )(xh such that the probability density (or mass) function f(x;θ) of Pθ can be written as

)](B)x(T)(exp[)x(h);x(f θθηη −= (1)

The parameter )(θη is called the natural parameter of the distribution, and )(xT is called the natural statistic. The family of distributions obtained by taking iid samples from one-parameter exponential families are themselves one-parameter exponential families. A useful reparametrization of the exponential family can be obtained by setting )(θηη = . Then the exponential family has the form

( ) [ ])(A)X(Texp)x(h;x\f ηηη −= , (2)

where, ( ) ( )∑==1i

ixTXT is a sufficient statistic, and

( ) ∫ ∫= xd)]X(Texp[)x(h....logA ηη in the continuous case and the integral is replaced by a sum in the discrete case. Therefore, )())(( ηAXTE ′= , )()]([ ηAXTVar ′′= , and the moment-generating function

( ) [ ])(A)s(Aexps ηηψ −+= for s in some neighborhood of 0, if it exists.

Morris (1982) has shown that exactly six basic types of natural exponential families (NEFs) have quadratic variance function (QVF). He considered normal, Poisson, gamma, binomial, negative binomial and the NEF generated by the generalized hyperbolic secant (GHS) distributions. However, Letac and Mora (1990) have given variance functions for the above six plus another six distributions that are inverse Gaussian, Abel, Takacs, strict arcsine, large arcsine, and Ressel, which have cubic variance function (CVF). In both these cases, it is clear that the variance is a polynomial function of the mean μ with degree less than or equal to 3, which can be described by

( )μFV = 33

2210 μξμξμξξ +++ (3)

where, ℜ∈3210 ξξξξ ,,, are constants.

Methodology and results

Gleaser and Hearly (1976) have considered the minimization of mean square error of linear combination of two uncorrelated and unbiased estimators of θ having a known coefficient of variation. In the following theorem, their results were generalized by considering one estimator for the parametric function ( )θg when the ratio ( )[ ] ( )[ ]XTVarg 22 −= θν is independent of θ . Note that in this case, the estimator ( )XT is not necessarily an unbiased estimator for ( )θg .

Theorem 1 Let ( )nXXX ,,K1= be a random sample from a population with distribution ( )θ;xf and

( )θg be a real-valued function on Θ . Let ( )XT


282

be a point estimator of ( )θg with ( )[ ] ( )θkgXTE = where ℜ∈k , and without loss

of generality, assume that 0>k . If the ratio ( )[ ] ( )[ ]XTVarg 22 −= θν is independent of θ ,

then ( ) ( )XTXT ** α= has uniformly minimum mean squared error (in ( )θg ) among all estimators that are in the class ( ) ( ) ∞<<= ααα 0|XTCT , where )/(* 22 να += kk . Proof: Since ( )[ ] ( )θα kgXTE =* , and

( )[ ] ( )[ ]XTVarXTVar 2α=* , the mean squared

error ( MSE ) of ( )XT * is

( )[ ] ( )[ ] ( ) ( )[ ] .* 222 1 θαα gkXTVarXTMSE −+=

Hence, it can be easily shown that the estimator

( ) ( ) ( )XTkkXT122 −

+= ν* minimizes MSE over ( )αTC , and the minimum MSE is given by

( )[ ] ( ) ( )[ ]21222 θνν gkXTMSE−

+=* Then it can be shown that

( )[ ])([* XTMSEXTMSE < . Therefore, it is clear that the estimator ( )XT * is uniformly better than the estimator ( )XT , and that ( )XT is inadmissible, and more generally

( )XT * is uniformly better than any other estimators in the class ( )αTC .

The above theorem can be applied for estimation of certain variance functions ( )μFV , for which the estimator is of the form ( )XT with 222 τν knc )(= , where )(nc , is a known constant depends on n , and τ is the coefficient of variation of the probability distribution which is assumed to be known.

Applications The following applications illustrate the use of the above results. Binomial distribution: Let

( ) r and,1p0,n1i,p,r~Xi <<= LΒ be fixed. In this case for an iid sample of B(r,p) one can identify

( )( ) ( ) ( ) ( ) ( )[ ].explog,log,

expexp

,log ηηη

ηη +=−−=

+=⎟⎟

⎠

⎞⎜⎜⎝

⎛

−= 11

11nrApnrpBp

pp

Then the mean and variance for the natural

sufficient statistic ( ) ∑=

=n

iiXXT

1

is ( ) nrpA =′ η and ( ) ( )pnrpA −=′′ 1η respectively. Then )(/ 21 τα += nr , where τ is the coefficient of variation of the distribution, which is assumed to be known, and 222 τν nr= . Thus, according to Theorem 1, the optimal shrunken estimator of the

parameter p is ( ) )(/* 2

1

τ+= ∑=

nrXXTn

ii .

Hence, )/( 2

1

τ+∑=

nXn

ii is the optimal

shrunken estimator of the mean rp=μ , which is precisely the estimator proposed by Wencheko and Wijekoon (2005). Using the derivatives of,

( ) ( )[ ]( )nr

T

)]exp(1/[)]texp(1[

AtAexp)t(

ηη

ηηΨ

+++=

−+=

which is the moment generating function of ( )XT and Theorem 1, it can be shown that the

optimal shrunken estimator of the function ( )pp −1 is

( ) ( )( ) ( )( )32121

11

−−++−⎟⎟

⎠

⎞

⎜⎜

⎝

⎛−= −

==∑∑ nrnrrrnrXnrXrXTn

ii

n

ii ττ/*

Note that in this case )( 1−= nrnrk and )()( pppg −= 1 . Hence,

( )( ) ( )( )32121

11

−−++−⎟⎟

⎠

⎞

⎜⎜

⎝

⎛− −

==∑∑ nrnrrrnrXnrXr

n

ii

n

ii ττ/ is

the optimal shrunken estimator of the variance ( ) ( ).prpVF −= 1μ Similarly, the optimal

shrunken estimator of the variance functions of some basic types of NEF”s are given in the following Table 1.

Conclusions When the coefficient of variation τ of the distribution is known the above admissible shrunken estimators of the variance functions have minimum mean squared errors in the class ( ) ( ) ∞<<= ααα 0|XTCT .

References Gleaser, L.J. and Hearly, J.D. (1976)

Estimating the mean of a normal distribution with known coefficient of


283

variation, Journal of the American Statistical Association, 71, 977-981.

Letac, G. and Mora, M. (1990) Natural exponential families with cubic variance functions, The Annals of Statistics, 18, 1-37.

Morris, C.N. (1982) Natural exponential families with quadratic variance functions, The Annals of Statistics, 10, 65–80.

Wencheko, E. and Wijekoon, P (2005) Improved estimation of the mean in one-parameter exponential families with known coefficient of variation, Statistical Papers, 46, 101-115.

Table 1. Optimal shrunken estimators of the variance functions of several distributions, which belong to NEFs

Name of the type ( )μFV

1 Normal ( )2σμ ,N ( ) )/( 11

2+−∑

=

nXXn

ini

2 Poisson ( )λPoiss )/( 2

1

τ+∑=

nXn

ii

3 Negative binomial ( )prNB , ( )( ) ( )( )321

21

11

2 +++−+⎟⎟

⎠

⎞

⎜⎜

⎝

⎛+ −

==∑∑ nrnrrrnrXnrXr

n

ii

n

ii ττ/

4 Gamma ( )λ,rGam ))(/( 32

2

1

++⎟⎟

⎠

⎞

⎜⎜

⎝

⎛∑

=

nrnrXrn

ii


284

Major and Trace Element Composition of Bottom Sediments of the Malagane Tank: Relationship with Sources

K. Mahatantila1,2, R. Chandrajith1* and H.A.H. Jayasena1,2 1Department of Geology, Faculty of Science, 2Postgraduate Institute of Science,


Introduction Sri Lanka has one of the oldest traditions of irrigation in the world, dating back as far as 300 BC. It was the basis of the Dry Zone prosperity in ancient Sri Lanka. An interconnected series of tanks within a small watershed is called a Tank Cascade System (TCS). In TCS, water from one tank flows to the downstream tank, while it is utilized for agriculture and other domestic purposes. A tank has three basic components; the bund, tank body (wewa) and the upper periphery which is a gently sloping land locally termed Thaulla.

Since tank sediments are formed mainly from material supplied from the terrestrial surroundings of the tank, the chemistry of sediment is a function of characteristics of the catchment including events of pollution. The composition of tank sediments reflects the chemical inputs from the surrounding environments and the anthropogenic influence within a particular ecosystem. Therefore, our main intention was to study the geochemical composition of tank bottom sediments in Sri Lanka and to determine whether the sediments represent average continental crust values or polluted material.

Methodology The Malagane tank in the Deduru Oya river basin located in the Intermediate Climatic Zone of Sri Lanka was selected for the study. Thirteen sediment samples were collected using a stainless steal auger at pre-defined locations. The pH of sediments was measured using 1:1 w/v sediment/water extractions. The percentage of organic matter in the sediments was determined as percentage loss on ignition (LOI) after drying the sediments at 550 °C. Available fraction of nitrogen and phosphorous in sediments was extracted using 1 mol dm-3 KCl and 0.5 mol dm-3 NaHCO3 (pH = 8.5), respectively. The available metals are extracted using 0.5 mol dm-3 CH3COOH and measured using atomic absorption spectrophotometry. The total elemental contents of sediment

samples were determined with Phillips PW-2400 X-ray fluorescence spectrometer. The recoveries of international reference samples were within ±5% RSD for major elements.

Results and discussion The spatial distribution of mean grain sizes of the Malagane tank shows the deposition of medium to coarse sand in Thaulla, where the inflow stream water enters the lake. Fine sand and sandy clay have been deposited one after the other and silty clay is predominant in the middle of the tank. Rate of water flow most probably controls the grain size in bottom sediments of tanks. However, a gradational variation has been observed from the middle of the tank towards the lake bund. Coarser sand layers are observed closer to the tank bund which may be due to scouring effects associated with hydraulic conditions caused by water released to the downstream paddy fields.

The pH of the sediment of Malagane tank varies from 4.87 to 6.55 with the mean value of 5.50. Sediments may become slightly acidic due to intense leaching of base forming cations. The LOI of the tank sediments varies from 4.8% to 16.9%. The organic matter concentrates at the centre of the tank with the clay layers. The Thaulla contains low amounts of organic matter (5.9%), which may be due to low retention of organics in sandy soils.

The mean P concentration of the sediment of Malagane tank is 1.44 mg/kg. The lowest value occurs closer to Thaulla and high contents occur associated with the clay sediments in the middle of the tank and closer to the tank bund area, which could be due to anthropogenic inputs. The mean nitrogen content of sediments of the Malagane tank is 51.8 mg/kg. The highest leachable N values were obtained closer to the tank bund and the content does not depend on the grain size. In Thaulla, where the biological activities are prominent, the denitrifying bacteria could convert the sediment nitrates into gaseous nitrogen and escape from the system or allow the plants to take up nitrates for their metabolism.


285

The available metals considered are Na, K, Ca, Mg, Fe, Mn, Ni, Zn, Pb and Cr, and their mean concentrations, in mg/kg, are 122, 170, 671, 2078, 1723, 240, 3.2, 5.2, 7.5 and 3.5, respectively. All the available metals show a general distribution pattern which is an association with clay sediments. The total content of elements of bottom sediments was compared with that of the Upper Continental Crust (UCC) values in order to determine the anthropogenic influence to the tank sediment. Since the average elemental levels of the terrain were not available, the bulk chemical composition of the sediments of Malagane tank was compared with the UCC values proposed by Rudnick and Gao (2003) (Figure 1). With few exceptions, the major and trace element compositions of Malagane tank sediments are either similar or slightly depleted (alkali and alkaline earth elements, P, Mn and Cu) to that of the UCC composition. As and V are enriched in sediments in the main tank body and sediments close to the bund. The Zr and Ce contents are enriched in the Thaulla and in the tank body, whereas Hf, Pb and Th are enriched throughout the tank compared with that of the UCC values. Since the Thaulla of the tanks acts as a sediment trap, heavy minerals supplied from the watershed are deposited mainly at Thaulla and only fine grains

including organic particles are flushed into the tank body.

Conclusions The analysis of sediments in the Malagane tank emphasizes that the sediments are comparable to the upper continental crust composition and therefore mainly derived from the upper catchment of the tank. Apart from the terrestrial materials, geochemical processes associated within the sediments also play a major role. The total metal concentrations and distribution indicates though extensive paddy cultivations are practiced in the tank watershed, the anthropogenic heavy metal pollution levels are not significant in the study area.

Acknowledgements Authors of the paper like to express their sincere acknowledgement to the National Science Foundation of Sri Lanka for the financial support given throughout the research project.

References Rudnick, R.L. and Gao, S. (2003) Composition

of the continental crust, Treatise on Geochemistry, 3, 1-64.

Figure 1. Average upper continental crust normalized elements from the Malagane tank


286

An Econometric Model for Hyper Inflation

H.G.K. Dineshanrathna* and U.N.B. Dissanayake

Department of Mathematics, Faculty of Science, University of Peradeniya Introduction Short-Run Philip curve provides useful information for policymakers to reduce the unemployment rate temporally. But, according to the non-accelerated inflation rate versus unemployment model (NAIRVUM), this reduction below the “Natural Rate” will be temporally and in the long run it leads to higher inflation, (en.wikipedia.org/wiki/Philips_curve) again.

Our objectives are to model the interaction of inflation with socio-economic variables in an abstract setup and to investigate its functional behavior via econometric analysis (EMA). This study is based on Sri Lankan economic factors and our aim is to investigate the geometrical significance of the explanatory variables against the β - weights of the crucial variables which may generate hyper inflation.

Materials and methods Inflation is the persistence increase in the level of consumer price or a persistence decline in the purchasing power of money, caused by an increase in available currency and credit beyond the proportion of available goods and services. In a non-abstract setup, measuring inflation is a mere arithmetic exercise. This is done by subtracting last year consumer price index (CPI) from this year consumer price index and converting it to percentage with respect to (w.r.t) the last year CPI.

In this study, inflation rate (inflation) is the explanatory variable and in the local context, the variables used to explain the inflation rate I are , UR=unemployment rates-U, MS=money supply-M, NIR=nominal interest rates-N, FER=foreign exchange rates-F, GE=government expenditure-G, EDS=external debt services-E, GDPGR=GDP-growth rate-R, POP=population-P, DC=domestic credits-C, PI=political instability-Y, WE=war expenditure-W, RUM=rural-urban migration-T. Here, we use pooled data, and the data source is Socio-Economic Survey Department of the Central Bank of Sri Lanka. Most of the available models constructed via casual modeling predict an inverse relationship

between inflation rate and unemployment rate. In this study, we shall analyze the multi-dependence of the inflation I w.r.t. the above mentioned twelve socio-economic factors (www.cbsl.gov.lk).

Increasing in unemployment rates, external debit servicing and growth rates of GDP are expected to decrease the inflation rates; increasing in money supply, nominal interest rates, real exchange rates, government expenditure, population and domestic credits are expected to increase the inflation rate. With this prior information for nine factors, we set the mathematical grounding of the model in the following format: I=ƒ﴾U, M, N, F, G, E, R, P, C, ε ﴿ ; ε=g(Y, W, T ) and linearizing the functional form as the preliminary step with partial regression slopes βi ; where i = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, we get I = β0 + β1 UR + β2 MS + β3 NIR + β4 FER + β5 GE + β6 EDS + β7 GDP + β8 POP + β9 DC +β10 ε ; where β1 , β6 , β7 < 0 ; β2 , β3 , β4 , β5 , β8 , β9 > 0. Using the data in the matrix format

1111113113 XY××× = β

and assuming ),0(N 2i σε ≈ for 131 ≤≤ i , we

compute the column vector ( ) ( )YXXX T1T −=β .

Exogenous parameters in the model are expected to have sign and size, which conform to the theory and practice. The significance of the estimates of parameters will be carried out at the level of 0.05 (standard significant level).

Results

H0 : βi = 0 for i∀ (Null Hypothesis) H1 : at least one βi 0≠ (Alternative Hypothesis) F-test

F- value = 846.8=MSEMSR (Figure 1);

n = 13, p = 10. F9,3 (0.05) = 8.81 < 8.846. Hence, the null hypothesis H0 is rejected and the functional


287

Inf = -94.5658 + 1.7213 UeR - 0.7812 RER + 0.2782 GoE + 2.0309 EDS - 0.6988 GDPGR + 13.1975 Pop

relationship for I is valid at the 5% significant level.

Figure 1. Probability distribution graph (F-test)

t-test H0 : βi = 0 (Null Hypothesis) H1 : βi 0≠ (Alternative Hypothesis)

T = 1013

)ˆ(

ˆ−≈

−t

Var i

ii

β

ββ ;(Figure 2)

T values corresponding to β values are given by (Figure 2)

0367.2

191.3

0801.4

1253.10

9

7

4

0

−=

−=

−=

−=

β

β

β

β

T

T

T

T

182.6

096.6

5837.4

203.3

9552.2

0221.2

6

5

1

8

3

2

=

=

=

=

=

=

β

β

β

β

β

β

T

T

T

T

T

T

Null hypothesis is valid for the coefficients of MS, NIR and DC. Thus, we infer that at the standard significant level, the coefficients β2, β3 and β9 must vanish and moreover, we get

0.92 < R2 = 0.9209 <1 1. 2 ≈Rei

Thus, the functional model is appropriate and the regression hyper plane representing the inflation function I take the following format in a MATLAB output (Table 1).

Figure 2. Probability distribution graph (t-test)

Conclusions Component of the β-vector indicates that unemployment rates, exchange rates, government expenditure, external debit services, GDP growth rates and increase in population are key-factors in the functional form for I at the 95% confidence level. According to our model, we infer that β-weights of UR, EDS and POP are major contributors for the hyperinflation; but, money supply, nominal interest rates, domestic credits do not appear as accelerators for the hyper inflation.

References Gujarati, D.N. Basic Econometrics http://www.cbsl.gov.lk/ http://en.wikipedia.org/wiki/Phillips_curve

Table 1. Inflation function

846.881.8)05.0(3,9 =F


288

Integer Solutions of Non - Linear Diophantine Equations Using Continued Fractions

A.G.K.N. Alupotha and A.A.I. Perera*

Department of Mathematics, Faculty of Science, University of Peradeniya

Introduction The origin of continued fractions is traditionally placed at the time of the creation of Euclid's Algorithm. Euclid's Algorithm is used to find the greatest common devisor (gcd) of two numbers. However, by algebraically manipulating the algorithm, one can derive the simple continued fraction of a rational number

qp as opposed to the gcd of p and .q It is well-known that integer solutions of a linear Diophantine equation ,cbyax =+ where

cba ,, ∈ Z, can be obtained by expressing ba as a simple finite continued fraction. This idea can be generalized for the general linear Diophantine equation;

bxaxaxa nn =+++ ...2211 , where baaa n ,,...,, 21 ∈ Z, can be solved by using

continued fractions. Here, when n is large we need more conditions to solve the above Diophantine equation using continued fractions.

A Non-linear Diophantine equation of the form ndyx =− 22 , where d and n are integers, is

known as the more general Pell’s equation, which can be solved for integer solutions by using continued fractions with additional two conditions. Further, this work has been generalized to a Non-linear Diophantine equation of the form

022 =+++++ feydxcybxyax , where ∈fedcba ,,,,, Z.

Integer solutions to this equation can be obtained subject to three more conditions.

Method Use Pell’s equation; ndyx =− 22 , where

∈nd , Z. Find integer solutions to Pell’s equation when d >0 and d ≠ m for all m∈N.

The following theorem can be used to find the integer solutions to 122 =− dyx .

Theorem: Assume that d (> 0) is not a square of an integer and that pk /qk is the kth convergent of d . Let s be the period of the simple continued fraction representation of d .

(a) The positive integer solutions of 122 =− dyx are ( ) ( )11 ,, −−= isis qpyx for 1≥i

when s is even and ( ) ( )1212 ,, −−= isis qpyx for 1≥i when s is odd.

(b) The positive integer solutions of 122 −=− dyx are nonexistent when s is even

and ( ) ( ) ( )( )1s1i21s1i2 q,py,x −−−−= for 1≥i when s is odd, where the two sequences np and nq are given by,

00 ap = , 1101 += aap , 2;21 ≥+= −− kppap kkkk and

10 =q , 11 aq = , .2;11 ≥+= −− kqqaq kkkk

(Anderson and Bell, 1997)

This can be extended to find the integer solutions to ndyx =− 22 by writing

nn .1= ( ) ( )[ ]( )222*2* dsrydx −−=

( ) ( )2**2** rysxdsdyrx ±−±= ,

where ( )sr, is a particular solution to ndyx =− 22 and ( )** , yx is an integer solution

to 122 =− dyx . Thus sdyrxr *** ±= and rysxs *** ±= is an integer solution to

ndyx =− 22 . Since we have infinitely many integer solutions for *x and *y , infinitely many integer solutions to our original Pell’s equation can be obtained.

Now consider a Non-linear Diophantine equation of the form

022 =+++++ feydxcybxyax , where ∈fedcba ,,,,, Z. Integer solutions to this

equation can be obtained with the following conditions:

(a) 0, ≠ca

(b) acb 42 − >0

(c) ( ) macb ≠− 44 2 for all m∈N.

Reduce this equation into a Pell’s equation of the form ,22 NMz =− ω and then obtain the


289

integer solution for it. Hence, infinitely many integer solutions for x and y can be obtained.

Result

Consider 022 =+++++ feydxcybxyax .

Solution ( )a

Ldbyx2

±+−= ,

where ( ) ( )feycyadbyL ++−+= 22 4 . Take =L =2ω ( ) ( )feycyadby ++−+ 22 4 for some integer ω . Then ,02 =++ CByAy where ,42,42 aebdBacbA −=−=

2ω−= DC and .42 afdD −= Take ACBz 422 −= ( )22 4 ω−−= DAB . Then, ,22 NMz =− ω where AM 4= and

.42 ADBN −= Solving this Pell’s equation, integer solutions for z and ω can be obtained. Hence, we can find infinitely many integer solutions for x and y . For an example, consider

.0153 22 =+++++ yxyxyx Then, 1,5,1,3,1 ===== edcba and .1=f

Since, 542 =− acb (>0) and ( ) ∉=− 2044 2 acb N, the above method

can be applied, where ,21,26,5 2ω−=== CBA 20,21 == MD and

.256=N Next we shall find integer solutions to .25620 22 =− ωz Then, ( ) ( )32,144, 11 =ωz

will be an integer solution to .25620 22 =− ωz Hence, 17

1014426

21 −=

±−=

±−=

AzBy or .

10118

Therefore, 171 −== yy and hence,

72

11 =±−−

=adby

xω and 39.

Then, ( )17,39 − and ( )17,7 − are integer solutions to .0153 22 =+++++ yxyxyx

Thus, we can find infinitely many integer solutions for given Non-linear Diophantine equation.

Discussion

If md = for some m∈N in ndyx =− 22 , then .0=s Since

1−p and 1−q are not defined d

cannot be a natural number. Integer solutions of the Diophantine equation 022 =+++++ feydxcybxyax , can be obtained using continued fraction under some conditions. Further, we have proved that these conditions are necessary to obtain the solutions.

References Anderson, J.A. and Bell, J.M. (1997) Number

theory with applications, Prentice-Hall, New Jersy.


290

Geochemical Characterization of Surface Water and Groundwater in Some Areas of Northcentral and Northwestern Sri Lanka

S.M. Young1, A. Pitawala2* and J. Gunatilake2 1Postgraduate Institute of Science, 2Department of Geology, Faculty of Science,


Introduction In the Northcentral and Northwestern regions of Sri Lanka, groundwater is a limited resource and is the main source of drinking water. The area which is of flat terrain receives relatively low rain fall with high seasonal and spatial variations, and has high evapotranspiration. The main groundwater bearing formations in the area are the fractured crystalline bed rock and the weathered overburden. The alluvial deposits along the streams present in the area also play a vital role in water supply. Almost all the groundwater comes from precipitation, which soaks into the soil and passes down to the aquifer. The regolith aquifer coincides with the areas where there exists the small tank cascade system since ancient periods. These aquifers are closely linked with the surface water in streams, canals and tanks. The geology of the area is dominated by Precambrian metamorphic rocks. The main metamorphic rocks of the area are charnockites, charnokitic gneiss, quartzite and calcgneiss. The objective of the study was to characterize the ground and surface waters found in Northcentral and Northwestern Sri Lanka.

Materials and methods For the relevant study, the groundwater and the surface water was categorized as (a) Lakes (b) Canals and streams (c) Shallow groundwater (Dug wells, Agricultural wells) and (d) Deep groundwater to study the variation of ions. The pH, temperature and the conductivity of 296 samples were measured during the sample collection in the field using the pH meter (PH 320/Set 1) and the conductivity meter (Model CM-7B, cell type CG-201PL instrument), respectively. Dissolved cations such as Na, Ca, Fe, Mn, K and Mg of the water were measured in triplicates using the Perkin Elmer Atomic Absorption Spectrophotometer (AAS). To minimize analytical errors, appropriate standard techniques were followed. Statistical software Minitab, Origin and Arc/GIS were used to carry out chemical data analysis.

Results The results show that the stream and canal waters are rich in Ca and Mg (Figure 1) although the other ions are considerably low. In contrast, lake water is characterized by many dissolved ions except Ca and Mg (Figure 2). The most interesting feature is that the highest values of Fe and Mn are in lake waters. The pH is also more towards alkaline in lakes (4.68 – 9.40) compared to that of streams and canals.

The dissolved ions in ground waters are comparably high. However, the deep groundwater has more dissolved ions and the shallow ground water is markedly characterized by higher K levels (Figures 3 and 4). In general, the concentrations of Fe and Mn are low in groundwater compared to surface waters. The pH is more alkaline in the agricultural wells and dug wells while it is more acidic in the tube wells. The agricultural wells are unusually high in Na.

Discussion During field investigations it was found that the water table is shallow. In lake waters, the high iron concentration gives rise to reducing conditions and the other ions which show high concentrations are due to high evapotranspiration (Guo and Wang, 2004). However, Na concentration is dramatically high due to mineral dissolution. The low Ca and Mg values in lakes may be caused by the precipitation of calcite and dolomite (Guo and Wang, 2004). The canal and stream water chemistry is complex and has no relationship with natural conditions.

When one compares the dug wells and the agricultural wells, the latter has high water soil interaction. Therefore, the dissolved ion concentrations may dramatically increase. In that case, due to the recycling of the same water, the saline condition can be developed and increased with time.


291

In the case of tube wells, there is no clear correlation with the geological formation. However, in the areas that have quartzite, dissolved ion content is low. Thereby, it can be suggested that the chemistry of groundwater depends on the geological conditions and the flow direction.

Conclusions The water chemistry of the area is principally controlled by the redox conditions, pH, intense agricultural practices, hydrological conditions, climatic conditions and underlying geology.

Further, the data obtained will enable to characterize the water in the area and be helpful to understand the water pollution due to natural and anthropogenic activities.

References Guo, H. and Wang, D. (2004)

Hydrogeochemical processes in shallow quaternary aquifers from the northern part of the Datong Basin China, Applied Geochemistry, 19, 19–27.

Figure 1. Cation variation (ppm) in canals/streams Figure 2. Cation variation (ppm) in lake water

Figure 3.Cation variation (ppm) in tube wells Figure 4. Cation variation (ppm) in dug wells/ agricultural wells


292

High-Speed Counter-Current Chromatography for the Isolation of Proanthocyanidins from Tea Flush

W.M.A.M.B. Wijekoon1, N.S. Kumar1* and P.A.N. Punyasiri2 1Department of Chemistry, Faculty of Science, University of Peradeniya

2Biochemistry Division, Tea Research Institute, Talawakelle2 Introduction Monomeric flavan-3-ols (catechins) and oligomeric proanthocyanidins are important constituents of tea (Camellia sinensis) flush. Proanthocyanidins (PA’s) are formed by the formation of inter-flavan links between monomeric catechins such as (+)-catechin and (-)-epicatechin. PA’s are widely distributed plant defence compounds, and have a general toxicity towards fungi, yeast and bacteria (Dixon et al., 2004). It has been postulated that the composition and nature of PA’s may be related to the increased resistance of some tea cultivars to infection of tea flush by the fungus Exabasidium vexans (Punyasiri et al., 2005), that causes Blister Blight leaf disease, the most serious leaf disease of tea in Sri Lanka. Tea is cultivated for its leaf, and tea flush is particularly susceptible to attack by E. vexans which attacks young and succulent tea leaves and stems.

High-speed counter-current chromatography (HSCCC) is a support-free liquid-liquid partition method that has been used for the separation of diverse groups of natural products. It is particularly useful for the fractionation of labile polyphenolic compounds which may undergo either spontaneous oxidation or oxidation by polyphenol oxidase. Pure samples were required for the assays of fungitoxic activity of PA’s towards E. vexans. A method involving HSCCC was developed for the separation of PA’s from tea flush. The present study resulted in the separation of five pure proanthocyanidin samples after a single HSCCC run.


Collection of plant materials Fresh tea shoots (two leaves and a bud) were collected from the experimental tea garden at the Tea Research Institute in Talawakelle.

Extraction of proanthocyanidins An extract of PA’s in aqueous 70% acetone was prepared from 1 kg of fresh tea leaves according to the procedure described previously (Tammer et al., 1994) and purified by solvent partition and chromatography on Sephadex LH-20. The effluent from the column was concentrated on a rotar vapor and freeze dried to give the PA extract.

HSCCC - Solvent systems for HSCCC Four different two phase solvent systems containing different ratios of hexane, EtOAc, MeOH and water were prepared. The two phase solvent system Hex : EtOAc : MeOH : H2O (1:5:1:5) was selected for the separation of the PA extract on the basis of the partition coefficient and settling time.

HSCCC Model CCC-100 Pharma–Tech Research Corporation was used for the separation. The PA extract (200 mg) was injected into the HSCCC through the injection port and samples were collected at an elution speed of 2.0 ml/min.

High-Performance liquid Chromatography (HPLC) The fractions collected were monitored by HPLC. HPLC instrumentation consisted of Waters Alliance 2690XE Separation module coupled to a Waters 996 photodiode array detector (PDA) and Waters Millennium 32 data system were used along with a Luna-5 µm Phenyl-Hexyl column, 4.6 mm × 250 mm (Phenomenx Inc, USA) with a guard column made of the same material. A linear gradient program of mobile phase A (9% acetonitrile containing 2% acetic acid) and mobile phase B (80% aqueous acetonitrile) was used for the analysis. Flow rate was 1.00 ml/min and the column oven temperature was maintained at 35 °C.


293

Results and discussion Stationary phase retention of the solvent system [(Volume of the Stationary phase in the HSCCC column/Total volume of the HSCCC column) × 100%] selected was found to be 60-65% and gave a good separation. A single HSCCC run resulted in the separation of six fractions PA-1, PA-2, FL-X, PA-3, PA- 4 and PA-5. HPLC of the fractions indicated that PA-2, FL-X, PA-3, PA-4 and PA-5 proanthocyanidin fractions separated were very pure (> 95%) while PA -1 was a mixed fraction (Figure 1). HPLC retention times (given in minutes, within parentheses) indicated that PA-1 (24.856), PA-2 (25.519), PA-3 (26.498), PA-4 (27.315) and PA-5 (26.669) were proanthocyanidins. The nature of the FL-X (23.921), fraction has not been established as yet. The samples isolated are to be used to assess fungi toxicity. The five PA fractions are sufficiently pure for structure elucidation using spectroscopic methods of analysis and for fungi toxic assays.

Conclusions HSCCC is a fast and efficient method for the separation of proanthocyanidins from tea flush.

Acknowledgments The authors acknowledge financial support from SIDA-SAREC.

References Dixon, R.A., Xie, D.-Y. and Sharma, S.B

(2004) Proanthocyanidins - a final frontier in flavonoid research? New Phytologist, 1-20.

Punyasiri, P.A.N, Abeysinghe, I.S.B and Kumar, V. (2005) Performed and induced chemical resistant of tea leaf against Exobasidium vexans infection, Journal of Chemical Ecology, 1315-1323.

Tammer, G.J., Moore, A.E. and Larkin, P.J. (1994). Proanthocyanidins inhibit hydrolysis of leaf protein by rumen microflora in vitro, British Journal of Nutrition, 71, 947-958.

Figure 1. HSCCC of crude extract of proanthocyanidin

Abs

orba

nce

(254

nm

)

Time (hrs)


294

Combined Catalytic Activity of Cation-Exchanged Montmorillonite and Camphorsulfonic Acid in the Preparation of Cumene from Benzene and 2-Propanol

S. Wijeratne1,2, R.M.G. Rajapakse1, D.T.B. Tennakoon1, H.M.N. Bandara1 and B.M.R. Bandara1*

1Department of Chemistry, Faculty of Science, 2Postgraduate Institute of Science, University of Peradeniya

Introduction Montmorillonite clay belongs to smectite family and has an expandable layer structure of aluminosilicate. The layered structure facilitates the uptake of cations such as Zn2+, Al3+ and Fe3+. Cation-exchanged clays show high Bronsted acidity due to protons in the interlamellar zone formed by polarization of coordinated water molecules. Such clays can function as solid acid catalysts in organic reactions (Richard, 1992).

Cumene, the starting material for the industrial preparation of phenol, has been formed in 26% yield by alkylating benzene with isopropanol in the presence of Al3+-montmorillonite (Wijeratne et al., 2006); isopropyl carbocation formed from isopropanol undergoes an electrophilic aromatic substitution reaction. With a view to improving the yield of cumene, we envisaged facile generation of isopropyl carbocation from an intermediate sulfonate ester, and examined the reaction of isopropanol and benzene in the presence of metal-cation-exchanged montmorillonite and camphorsulfonic acid.


Preparation of catalyst Na+-Montmorillonite clay (5 g) was stirred overnight with a 0.5 M solution of cation chloride (pH 3.5, 200 ml) to obtain Mn+-montmorillonite clay catalyst (Mn+ = H+, Na+, Zn2+, Cd2+, Cu2+, Al3+, Fe3+, Ce4+). The clay was then centrifuged and washed with distilled water repeatedly until washings showed negative test for chloride ions. The clay sample was then dried under ambient air for a week and ground to pass through a mesh of size 100. The clay samples were characterized using their XRD patterns and FT-IR spectra. The catalyst was activated at 150 0C for 2 h prior to the study of its catalytic activity.

Isopropylation of benzene 2-Propanol (50 mmol), benzene (100 mmol) and Mn+-montmorillonite (0.5 g), 10-camphorsulfonic acid (0.5 g) were placed in a two necked flask equipped with a Dean-Stark apparatus. The reaction was maintained at reflux temperature for 48 h. The mixture was then allowed to reach room temperature and filtered to separate the clay catalyst. The filtrate was distilled under reduced pressure to collect the fraction containing cumene. The effect of reaction time, molar ratio of reactants and amount of catalyst on the yield of cumene was investigated. The product was characterized using an authentic sample of cumene (FT-IR, 1H-NMR, gas chromatography).

Results

Effect of different catalysts on isopropylation of benzene As expected, camphorsulfonic acid alone did not produce cumene from the reaction of benzene with isopropanol. However, the reaction mixture of camphorsulfonic acid, benzene, isopropanol and Mn+-montmorillonite (Mn+ = H+, Al3+ or Fe3+) furnished cumene in 60% yield; with Mn+-montmorillonite (Mn+ = Zn2+, Cu2+ or Cd2+) the yield was 50%. The reaction mixtures containing Na+ or Ce4+-montmorillonite did not produce cumene.

Effect of amount of clay catalyst Isopropylation of benzene in the presence of camphorsulfonic acid was carried out with varying amounts of Al3+-montmorillonite (0.1–1.0 g). With small amounts (0.1 or 0.2 g) of the clay, the yield of cumene was 20%; with 0.3 g the yield increased to 40%. Cumene was isolated in 60% yield when 0.5 g or more (0.8, 1.0 g) clay catalyst was used.


295

Effect of reaction time The highest yield (60%) of cumene was obtained when the reaction time was 40 h or more (50 h). At 10 h, 20 h and 30 h of reaction time, the yield of cumene was 0, 20% and 30%, respectively.

Discussion Alkylation of benzene to provide alkyl benzene is generally carried out by a Friedel-Crafts reaction using an alkyl halide and a Lewis acid such as AlCl3, FeCl3, ZnCl2 and SnCl4. Alkyl halides, their precursors and Lewis acids are hazardous to the environment. Industrial preparation of isopropylbenzene (i.e., cumene) employs high temperatures and pressures (250°C, 30 atm) in addition to Lewis acids/phosphoric acid. We have prepared cumene in 26% yield from isopropanol and benzene under mild conditions (80 °C, 1 atm) using the clay catalyst, Al3+-montmorillonite (Wijeratne et al., 2006).

In the present study, we observed that introduction of camphorsulfonic acid in catalytic amounts to the reaction mixture considerably increased the yield from 26% to 60%. Mn+-montmorillonite presumably catalyzes the initial formation of isopropyl camphorsulfonate from isopropanol and camphorsulphonic acid. The sulfonate group being a good leaving group, Mn+-montmorillonite readily generates the carbocation for subsequent isopropylation of benzene. In the latter step, camphorsulfonic acid is released. The absence of cumene in the

reaction mixtures containing Na+ or Ce4+-montmorillonite could be accounted for by the low polarizability of Na+ ions and the oxidation of isopropanol by Ce4+.

Conclusions Cation-exchanged montmorillonite and camphorsulfonic acid serve as catalysts in the reaction of benzene and isopropanol to give cumene under mild conditions. Camphorsulfonic acid potentiates the catalytic activity of Mn+-montmorillonite enhancing the yield of cumene from 26% to 60% (with Mn+ = H+, Al3+ or Fe3+) or 50% (with Mn+ = Zn2+, Cu2+ and Cd2+). The clay catalyst is cheap and reusable and does not produce hazardous by-products in the reaction. Low temperatures and low pressures make this process not only eco-friendly but also economically viable.

Acknowledgements Financial assistance by the National Science Foundation, Grant RG/2005/FR/04 is acknowledged.

References Richard, W.M. (1992) Inorganic Materials,

Wiley. Wijeratne, S., Perera, W.G.M.S., Bandara,

B.M.R, Rajapakse, R.M.G, Bandara, H.M.N. and Tennakoon, D.T.B. (2006). Electrophilic alkylation of Benzenoids with 2-Propanol and Al3+- Montmorillonite clay catalyst, Proceedings of the Peradeniya University Research Sessions, 11, 182.


296

Adsorption of Chromium (III) on Fired Brick Particles

N. Priyantha* and C. Seneviratne

Department of Chemistry, Faculty of Science, University of Peradeniya Introduction Chromium is present in the environment in both trivalent and hexavalent oxidation states. Cr(III) occurs naturally and is an essential micronutrient that is involved in metabolizing sugar, protein and fat (Park and Jung, 2001). Heavy metals such as chromium are not decomposed through biological means, and they are toxic to aquatic organisms as well as humans if exposure levels are sufficiently high. Chromium compounds are present in many types of industrial effluents, including electroplating, metal finishing, leather tanning, pigments and photography. In order to comply with the tolerance limits, it is essential that industries treat their effluents to reduce the chromium to acceptable levels before discharge in order to maintain environmental quality and human health. Ion exchange, electrochemical precipitation, chemical precipitation and adsorption are some acceptable treatment methods practiced worldwide (Kocaoba and Akein, 2004). Most of these methods suffer from drawbacks such as high capital and operational cost and/or problems associated with the disposal of sludge. The objective of this research is to investigate the removal of Cr(III) species from aqueous solution, through adsorption, by brick particles fired at different temperatures, and to optimize the firing temperature for the most efficient removal.

Materials and methodology

Materials Standard solutions of Cr(III) were prepared using Cr2(SO4)3 (98% assay). Unfired, dry brick clay samples obtained from Gelioya, Kandy, were first sieved to obtain particles of diameter < 1.0 mm, and fired in the laboratory at 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C and 900 °C.

Instrumentation The Carbolite CTF 12/100/900 furnace was used to fire brick clay samples. GBC 933AA model Atomic Absorption Spectrometer was used to measure Cr(III) concentration, while DRT-model ISCE turbidity meter was used for turbidity measurements.

Research design The amount of Cr(III) adsorbed by brick was determined by treatment of standard Cr(III) solutions of concentration varying from 1.00 mg dm-3 to 50.0 mg dm-3 with brick samples fired at each temperature. These measurements were then used for adsorption isotherm analysis. Comparison between the percent Cr removal from aqueous solutions and the turbidity of aqueous brick suspensions was also investigated.

Results and discussion The amount of Cr(III) ions (in µg) adsorbed on a unit mass (1.000 g) of laboratory fired brick clay samples (d < 1.0 mm) varies linearly with the initial concentration of Cr(III) in solution for samples fired up to 400 °C. Samples fired at higher temperatures show less extent of adsorption at all concentrations investigated, and further they obey Type I adsorption isotherm (amount adsorbed vs. concentration), reaching saturation at higher concentrations. This observation supports monolayer coverage, suggesting the formation of inner sphere complexes between Cr(III) and surfaces of minerals containing Fe, Al and Si present in brick matrix. Change in the extent of adsorption with temperature is probably due to phase changes and chemical processes that would occur at high temperatures.

An interesting feature observed thorough these measurements is that the percent removal of Cr(III) by brick generally increases up to a certain intermediate temperature followed by a decrease at high temperatures. However, turning points of percent removal – temperature curves, and the shape of the curves depend on the initial Cr(III) concentration (Figure 1).

Aqueous suspensions prepared using brick particles fired at temperatures between 200 °C and 600 °C are very clear while those at lower and higher temperatures are not.


297

Figure 1. Percent removal – temperature relationship for (♦) 10 ppm Cr(III) and () 50 ppm Cr(III)

Figure 2. Turbidity of aqueous suspensions of brick particles fired at different temperatures. (♦) no Cr(III) () 10 ppm Cr(III) () 50 ppm Cr(III)

This is evident through turbidity measurements shown in Figure 2, where the turbidity is initially decreased from 1200 NTU, then leveled off at a value less than 50 NTU, and finally increased up to 800 NTU. When Cr(III) is introduced to brick particle suspensions, turbidity is decreased for all concentrations higher than 10 mg dm-3 Cr(III). Nevertheless, the general shape of turbidity – temperature relationship is not changed significantly.

When both turbidity and percent removal are considered, brick fired at intermediate temperatures range results in low turbidity and high Cr(III) removal. This behavior although depends on the initial concentration of Cr(III), a firing temperature of 400 °C is selected as the optimal temperature for the most efficient removal and the lowest turbidity.

Conclusions The adsorption behavior of Cr(III) on brick particles highly depends on the initial Cr(III) concentration and the firing temperature of brick. Although the Cr(III) /brick system obeys both the Langmuir and Freundlich adsorption isotherms, brick treated at higher temperatures tend to follow monolayer adsorption. Comparison of turbidity of brick particle suspensions to which Cr(III) are added and the percent Cr(III) removal clearly indicates that the optimum temperatures for the highest removal and lowest turbidity is 400 °C. Such finding would be extremely important in designing effluent treatment methodologies using fired brick particles, a low-cost and a readily available material.

References Kocaoba, S. and Akein, G. (2004) Adsorption

Science and Technology, 22, 401-410. Park, S. and Jung, W. (2001) Carbon Science,

2, 15-21.

0

200

400

600

800

1000

1200

0 300 600 900

Temperature/ 0C

Turb

idity

/ NTU

0

20

40

60

80

100

0 300 600 900

Temperature/ 0C

% R

emov

al


298

Chemical Reactivity of Mica, K-Feldspar and Apatite in Organic Acids and Water

T.H.N.G. Amaraweera1,3, A. Pitawala1,2* and G.W.A.R. Fernando2,4 1Postgraduate Institute of Science, 2Department of Geology, University of Peradeniya

3Department of Science and Technology, Uva Wellassa University

4Department of Physics, The Open University of Sri Lanka

Introduction Mineralogical characteristic of minerals and biogeochemical processes in nature are the key factors controlling the chemical weathering process that leads to the release of ions from the mineral which provide the essential elements for higher plants, with the exception of nitrogen. Therefore, study of the short term stability of mica, feldspar and apatite in different geochemical conditions leads (1) to identify the least stable mineral under natural conditions, (2) to estimate the possible potential for use as fertilizer and (3) to understand the stability of mineral mixtures.

Materials and methods Different proportions of powdered minerals (< 125 µm) were mixed with (1) organic matter with water, (2) water and (3) 2% citric acid. The mixtures were kept under ambient conditions while controlling the moisture content. The water soluble ionic concentrations of each mixture were measured and their variations with the time were studied.

Results According to Figures 1 and 2 both mica and feldspar release higher values of potassium compared to other ions when they are in water or in moist organic matter.

Figure 1(a) Feldspar

Figure 1(b) Biotite

Figure 1(c) Organic matter and apatite (5:1

w/w)

Figure 1. Variations of concentrations of available ions of treated minerals with organic matter



299

Figure 2(b) Biotite

Figure 2(c) Apatite

Figure 2. Variations of concentrations of

available ions of treated minerals with water

The trend shows that the calcium, magnesium, sodium gradually increase from all the mineral – organic matter mixtures although potassium released is decreased except from the mixture containing mica. Magnesium, iron and manganese contents in water is constant throughout the period in all the mixtures while the potassium and the sodium content appear to be reaching to a constant value. Mixture of water and biotite is characterized by the highest iron concentration compared to others. Calcium content in water shows irregular variation in the systems containing apatite.


Figure 3(b) Biotite

Figure 3(c) Apatite

Figure 3. Variations of concentrations of

available ions of treated minerals with 2% citric acid

Figure 4(a) Feldspar (10 g) + biotite (10 g)

Figure 4(b) Feldspar (10 g) + apatite (10 g)


300

Figure 4(c) Apatite (10 g) + biotite (10 g)

Figure 4. Variations of concentrations of available ions of treated mineral mixtures with 2% citric acid

Release of ions from the mineral and the mixture of minerals in the acidic media (pH = 2-3) is illustrated in Figure 3 and 4. Mica releases considerably higher amounts of iron while the apatite releases higher amount of calcium. Rapid increases of calcium from the apatite and the iron from biotite were noted. The results clearly indicated that the amount of calcium releases from apatite and feldspars are affected by the presence of biotite under the acidic conditions.

Discussion Systems with biotite release more ions into the systems as the interlayer ions were easily leached from the mica structure. Apatite containing phosphate anionic complex is less

stable than the tectosilicates feldspars and hence feldspars are more stable in both natural solutions and citric acid medium.

Under the higher acidic conditions, all minerals release more ions than natural conditions since process of chemical weathering is more rapid than the number of biogeochemical reactions in natural systems. Release of higher concentrations of iron from the biotite in acidic medium inhibits the release of Ca from the apatite and the feldspars due to formation of complexes.

Conclusions Dissolution of minerals is controlled by their mineralogical characteristics and the chemical nature of solutions. Mica and apatite can be used as multi-nutrient fertilizers for long term crops growing on acidic soils.

Acknowledgements Financial support from the NSF research grant RG/2005/EB/01 is acknowledged.

References Weerasuriya, T.J., Pushpakumara, S. and

Cooray, P. I. (1992) Acidulated pegmatitic mica:A promising new multi-nutrient mineral fertilizer, Nutrient Cycling in Agroecosystems, 34(1), 6.


301

Deterioration of Groundwater Quality in Tsunami Affected Coastal Aquifers in Sri Lanka and Complexities in Natural Recovery

H.A. Dharmagunawardana1*, A. Welagedara1, A. Pitawala1 and M.N.A. Mubarak2 1Department of Geology, Faculty of Science, University of Peradeniya

2Industrial Technology Institute, Colombo 07 Introduction In December 2004, tsunami inundated and thereby contaminated about 40,000 dug wells and a considerable number of surface water bodies. Therefore, potable water supply systems that were based on groundwater became unusable. Contamination of groundwater became a massive problem to be solved in the affected areas. In general, deep sea sediments contain a large variety of organic and inorganic chemical compounds including heavy metals, some of which can be toxic (Jacobs et al., 1987).

The present study was carried out in the west coast of Sri Lanka, between Ambalangoda and Rathgama towns in the Galle district (Figure 1). This highly variable nature of geology and environmental conditions within short distance makes groundwater quality highly variable. The purpose of the present study is to understand the natural processes of ground and surface water quality improvements with time, under the influence of prevailing environmental conditions.

Materials and methods Sixty five sampling points, including dug wells, tube wells and surface water bodies were selected, and sampling was done at four occasions during the period between December, 2005 and December, 2006. Water samples were analyzed for heavy metals, nutrients. pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), dissolved oxygen (DO) and temperature. A portable multi-parameter meter and ELE portable turbidity meter were used for determining general chemical parameters. Heavy metals (Hg, As, Cd and Pb) were analyzed using Varian atomic absorption spectrophotometer (AAS) while phosphate and nitrate levels were determined using standard methods (APHA, 20th edition).

Figure 1. The study area showing the soil

types and surface environmental conditions

Results and discussion The concentrations of the heavy (trace) metals appear to be significantly low and are mostly below the detection limits. This indicates that the possible effect on water quality by the (analyzed) heavy metals that were brought by tsunami water or the agitated sediments, is not significant at most places. One out of five tube wells sampled showed contamination by nutrients. The dug wells in marshy environment where the water table was very shallow were also showed contamination by nutrients.

Based on the groundwater salinity levels observed in December, 2005, the dug wells could be arranged in the order from low to high salinity (Figure 2). When comparing the results of subsequent salinity measurements in the same wells, interesting behavioral patterns can be seen (Figure 2). The wells with high salinity


302

as seen in Figure 2 have shown rapid decrease with time. Majority of these wells were situated close to the coast and had inundated by the tsunami water. Wells with originally moderate and low salinity on the other hand (Figure 2) do not show a fast or a significant change with time. These wells thus could be assumed to be saline even prior to tsunami.

Figure 2. Salinity variation in dug wells

Figure 3. Salinity variation in tube wells

The salinity levels of the tube wells have shown an increasing trend with time (Figure 3). Of these tube wells, TW100 is located near the tsunami boundary, TW 101 and 103 within the tsunami flood zone and TW102 and 104 outside the tsunami zone.

The area wise distribution of the salinity of groundwater at different times is shown in Figure 4. It is seen from the salinity maps of

Figure 4 that there is no definite trend of temporal or spatial salinity variation other than slight shrinking of the high salinity zones with time. This situation can be attributed to the previously mentioned diversified geological and environmental conditions of the area. Water quality also appears to be dependent on recharge conditions, sandy, peaty, or lateritic soil compositions, local morphology and presence of marshy conditions of the area. This can be seen when compared to the geographic distribution of salinity with the surface geological and environmental conditions (Figure 1) of the area. High evaporation associated with shallow groundwater level in the vicinity of marshes can retard the rate of decrease of salinity created by the tsunami. In addition, intrusion of saline water from brackish water streams and other surface water bodies can further complicate and mask the natural salinity decreasing processes.

Conclusions Ground waters in the tsunami affected coastal areas have been faced quality problems of diversified nature. Increase in salinity has become the most significant problem while contamination with respect to nutrients has been evident mostly in marshy areas with shallow groundwater table. Heavy metal contamination however, is not significant. Groundwater quality has shown a slow recovery with respect to salinity. Complex geological and environmental conditions in the area however, complicate and mask the natural rates of recovery.

Acknowledgements Financial support from NSF research grant RG/05/DMM/03 is acknowledged.

References Jacobs, L., Emberson, S. and Huested, S.S.

(1987) Trace Metal Geochemistry in the Cariaco, Trench, Deep-sea Research, Royaume University, Oxford: Pergamon. 265-284.


303

(a) (b) (c)

Figure 4. Variation of Salinity of ground water with time (a) December 2005, (b) August 2006 and (c) December 2006


304

Synthesis of a Novel Copper (II) Complex Capable of Trapping Hazardous Cations Present in Water

A.M.K.S.P. Adhikari and M.Y. Udugala-Ganehenege*

Department of Chemistry, Faculty of Science, University of Peradeniya

Introduction Coordination complexes containing macrocyclic ligands play a significant chemical role in biological systems. Recently, a novel dicopper macrocyclic complex synthesized has shown a significant affinity towards trapping halide ions (Udugala-Ganehenege et al., 2001). Extension of such a study to synthesize a new, simple metal macrocyclic system capable of trapping hazardous molecules and ions present in the environment was the major objective of the present study. It was found that there were wide varieties of medicinally important transition metal complexes synthesized by using dithiooxamide (rubeanic acid) as a macro ligand. Many of these complexes have been polymeric due to the fact that dithiooxamide is being a tetradentate ligand. It has been reported that a polymeric structure is formed by chelating the N and S ends of the dithiooxamide with metal ions such as Hg(II), Pb(II), and Pd(II). However, N, N chelation is preferred for metal ions such as Ni(II) and Cu(II). Further, macro ligands such as N,N-bis(2-aminoethyl)-1,3-propanediamine are first coordinated to divalent metal ions (M2+) such as Cu(II) and Ni(II), followed by condensation reactions with acetylacetone to form M(II)ATH2 type macrocyclic complexes during the template synthesis (Martin and Cumming, 1973). In the present study, we attempted to synthesize a similar monomeric complex by using dithiooxamide for preparing corresponding dimeric or polymeric complexes of the type reported previously by the author. Due to the unusual insolubility of the complex formed, the research was focused towards trapping cations into the complex. This research report describes the synthesis and the specific ion trapping capacities of the Cu(II) complex of which the possible structures are shown in Figure 1.


Synthesis The chemicals used in the synthesis were of reagent grade. Cu(CH3COO)2.H2O (0.831 g,

0.0042 mol) was dissolved in distilled water (70 cm3). Recrystallized dithiooxamide (1.000 g, 0.0084 mol) was dissolved in methanol (140 cm3) and this solution was added into the blue colored Cu(CH3COO)2.H2O solution. A portion (50 cm3) of the resulting greenish black colored mixture was decanted off and the precipitate (Complex-a) was filtered, washed with methanol and distilled water, and dried. Acetylacetone (5 cm3) was added into the remaining mixture and refluxed for two hours. After refluxing, it was kept at room temperature for 30 min. Then the resulting black colored precipitate (Complex-b) was filtered, washed with methanol and distilled water, and dried.

Figure 1. Possible structures for the Cu(II)

complex (Complex-b)

Ion exchange study A column with a 0.5 cm diameter and a 5 cm height was packed by Complex-b. An aqueous Ag(I) ion solution [0.01 mol dm-3 (M), 3 cm3 at a time with a flow rate of 0.8 cm3 min-1] was passed through the column. The effluent was tested with aqueous NaCl (1.0 M) and conc. ammonia. Similarly, aqueous solutions of Pb(II), Cd(II), Ni(II) and Zn(II) were passed through separate columns packed by Complex-b and precipitated with suitable reagents. Atomic absorption (AAS) and cyclic voltammetric (CV) data were collected for the effluents after passing dilute solutions of the above cations.

Results Physical Properties of the complex is shown in Table 1. FTIR and XRD spectra of Complex-b are shown in Figure 2 and Figure 3, respectively.


305

Table 1. Physical Properties of Complex-b

Figure 2. FTIR spectrum of Complex-b

1 0 2 0 3 0 4 0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

1 8 0

2 0 0

Inte

nsity

2 - t h e t a v a lu e

Figure 3. XRD spectrum of Complex-b

Discussion

The hardness of the complexes is between finger nail and calcite according to the Mohs hardness scale. IR data show significant differences in spectra of free dithiooxamide and metallo-derivatives in the region of N-H absorptions. The band at 3137 cm-1 attributed to N-H stretching frequency is sharper and higher in frequency in metallo-derivatives compared to that of free dithiooxamide. The presence of additional strong bands at 872 cm-1 and 1518 cm-1, and the absence of a strong band at 1577 cm-1 corresponding to the C=O stretching frequency of Cu(acac)2 fragment confirm the formation of a macrocyclic complex. The decrease in the intensity of the major band of the XRD spectrum for Complex-

b may be due to the loss of intensity as a result of scattering of radiation between the pores present in the particles. The particle sizes calculated using XRD data and the Debye-Scherrer formula is 13.24 nm, which is 3 nm smaller compared to that of the corresponding dithiooxamido complex. Interestingly, the reduction in the size of the new complex together with the reduction in intensity of the XRD peaks compared to the copper(II) dithiooxamido complex may also be indicative of the packing of the molecule to form a macrocyclic configuration. Analysis of the data obtained in Tables 2 and 3 implies an interesting affinity of the complex towards Ag(I) ions. However, the test results reveal that the ions such as Pb(II), Cd(II), Zn(II) and Ni(II) neither trap nor release Cu(II) ions by the complex. According to the AAS data shown in Table 3, the copper complex used has trapped Ag(I) up to 20 ppm solutions without releasing Cu(II) ions. When the concentration of the Ag(I) ions exceeds 20 ppm, it starts to release Cu(II) ions from the complex while trapping Ag(I) ions into the complex. This observation is consistent with the XRD data which indicates the presence of some pores with the sizes compatible to the size of Ag(I) ions.

Table 2. Testing for Ag(I) ions using AAS

Colour and Appearance

Shiny, black solids

Hardness 2.5-3.0 (Mohs scale)

Solubility Insoluble in almost all solvents except conc. HNO3 and HCl

M.P. > 280 ºC

Streak colour Dark gray

Concentration of the Ag(I) solution

(3 cm3) passed

Absorption for Ag(I)

Absorption for Cu(II)

5 ppm - -

10 ppm - -

20 ppm - 0.002

20 ppm - 0.004

20 ppm - 0.005

100 ppm - 0.029

100 ppm - 0.046

100 ppm - 0.065

0.001 M - 0.092

0.001 M - 0.122

0.001 M - 0.141

0.002 M - 0.172

0.002 M - 0.233

0.002 M - 0.254

0.010 M - 0.614

500 1000 1500 2000 2500 3000 35000.0

0.1

0.2

0.3

0.4

0.5

0.6

Inte

nsity

W ave Num ber cm -1


306

Table 3. Ion exchange ability (Complex-b)

Conclusions In summary, a blackish shiny Cu(II) complex with the particle size of 13.2 nm and hardness of 2.5-3.0 has been synthesized by treatment of Cu(II), dithiooxamide and acetylacetone. It is difficult to study the solution chemistry of the compound because it is extremely insoluble in almost all the solvents. IR and XRD data reveal that the structure of the new compound is different from both copper(II) dithiooxamido and copper(II) acetylacetonato complexes, and the N-end of dithiooxamide is primarily bonded to the metal center showing a possibility of having pores in the complex. AAS of the effluent collected by passing a

solution of Ag(I) ions through a column packed by the copper(II) complex shows a substitution of Cu(II) ions of the complex only with Ag(I) ions specifically and not with other ions such as Pb(II), Cd(II), Ni(II), Zn(II) at concentrations above 20 ppm. The unusual behavior of the new complex may be used for the application of this type of systems for specific trapping of some other noble ions such as Au(I).

Acknowledgements Financial support given by NSF (Grant No RG/2006/FR/02) is appreciated.

References Martin, T.G. and Cumming, S.C. (1973)

Square-planar nickel(II) and copper(II) complexes containing 14- and 15-membered macrocyclic ligands, Inorganic Chemistry, 12, 1477-1482.

Udugala-Ganehenege, M.Y., Jane, M., Hryhorczuk, M., Wenger, I.O.E. and Endicott, J.F. (2001) Electron/atom transfer in halo-bridged homo-bimetallic complexes, Inorganic Chemistry, 40, 1614-1625.

Aqueous solution passed

Precipi-tating agent

Precipi-tate with effluent

Effluent with conc. ammonia

0.01 M Ag (I) NaCl - Blue solution 0.01 M Pb (II) NaCl White No change 0.01 M Cd (II) NaOH White No change 0.01 M Ni (II) DMG Red No change 0.01 M Zn (II) K2CO3 White No change


307

Learning Chemistry Using Analogies

M.M. Jamila1 and S. Karunaratne2* 1Postgraduate Institute of Science, 2Faculty of Science, University of Peradeniya

Introduction In Sri Lankan schools, students in the GCE advanced level science classes study chemistry as a subject. They generally consider chemistry as a difficult subject to learn because of its abstract nature of the concepts. The content of chemistry deals with chemical processes and entities that are submicroscopic, which make the subject difficult for students who do not readily visualize or think at abstract levels. In the normal classrooms, teachers generally do not use audio visual aids or other teaching techniques to make the content easier to understand. Frieedal et al., (1990) found that the use of analogies in teaching chemistry at secondary level enabled to help students in their learning process. The aim of this study was to use analogies in teaching chemistry at GCE advanced level to promote learning without encountering problems.

Methodology The study was conducted in three phases. In the first phase, one classroom was observed in an urban school when teaching chemistry lessons on the sub-topic, “Chemical Equilibrium” of the twelfth unit of the GCE advanced level chemistry syllabus in order to understand the problems faced by teachers and students in the classroom. After studying several research reports on analogies, lessons with activities based on analogies were developed in the second phase of the study to provide visualization of the abstract nature of concepts relating to real world applications and to encourage the teachers to consider students’ prior knowledge. Some of the analogies used were a boy and an escalator, a man swimming against the current, ants and a meter ruler, and a sailor and a boat, to build up the concept of dynamic equilibrium. As a part of the teaching/learning process, assessment activities were also developed using new analogies for which the students were not familiar in the class. This enabled the researchers to gauge the level of understanding of students. Further discussions were also made with teachers who were going to implement the planned lessons in order to get a clear understanding of analogies.

In the third phase of the study, four classrooms were selected from four other urban schools. Two classrooms were treated as the control group (n=45) and the other two classrooms were treated as the experimental group (n=45). A pre-test was administered to all classes in both control and experimental groups. The two teachers in the control group classrooms used their own teaching method. Developed lessons were tried out by the two teachers in the classrooms of the experimental group. They also used the same number of periods used by the teachers in the control group. The classrooms were observed while implementing the prepared lessons to identify how analogical strategies help students in learning. A post-test was administered to all four classes after the completion of teaching the unit. Data were analyzed using the results of the pre-test and the post-test using the two sample t-test.

Results and discussion It was found out that most of the time, the students in the control group classrooms only listened to their teacher passively with no questioning or without doing any activity in the learning process. They were conscious in taking down notes given by the teacher. Discussions with the teachers on developed lessons revealed that they were enthusiastic in using analogies. They enjoyed practicing the analogies in their teaching and expressed that they wanted to try analogies for some other units too. Teachers were also able to give some other analogies with the practice for individual students who indicated lack of understanding. According to the teachers, analogies helped them to explain easily the difficult or challenging ideas and to present abstract nature of concepts in a simple way. Student interviews revealed that they felt comfortable in learning chemistry as analogies helped them to understand and remember the lesson more easily than they would be without the analogies. For example one student said, “I like the analogies. They break up the class. We do not want just to look at the blackboard and take down notes. They help me learn difficult ideas easily. It’s really fun.” Another student


308

said, “I think it’s really important to give an analogy without explaining more and more when we get confused.” Pictorial analogies seemed to clear up confusion about the analogue concept that teachers were using. The students also thought that analogies would be useful to explain or describe objects or processes that are too small that they cannot be seen with the naked eye. One student said, “Whenever the concepts that the teacher teaches at a level that we actually cannot see what’s going on, it’s good to use analogies.” At the end of the lessons some students were able to make some analogies based on concepts relating to their real world experiences.

Analysis of the pre-test results showed that there was no difference between mean values of control (49.2) and experimental groups (49.0). Standard deviations were 12.8 and 14.4, respectively. Using the two sample t-test, it was found that there was no significant difference at p=0.05 between the control group and the experimental group of the pre-test results. Analysis of the post-test results showed that there was a difference between mean values of the control (32.29) and experimental groups (83.07). Standard deviations were 10.48 and 9.43, respectively. Using the two sample t-test, it was found that there was a significant

difference at p=0.05 between the control group and the experimental group.

Conclusions Analogies had a motivational impact on the students. Students could be made interested to learn abstract concepts in chemistry by using analogies in classroom teaching. Analogies not only help to explain or introduce difficult concepts in chemical equilibrium but also to make students attentive and actively involved in the lessons. In addition, use of analogies enables to have high interaction between the teacher and students, and among students. It is recommended that teachers need to develop a personal set of useful analogies in their teaching. It is necessary to select appropriate analogies that could be related to students own experience without misleading or confusing them. Otherwise they may lead to misconceptions. Therefore, teachers should pay more attention in selecting analogies for their explanations.

References Frieedal, A.W., Gabel, D.L. and Samuel, J.

(1990) Using analogies for chemistry solving: Does it increase understanding? School Science and Mathematics, 90, 674-682.


309

Determining the Optimal Order Quantity Using a Simulation Model

T.H.K.R. De Silva and W.B. Daundasekara*

Department of Mathematics, Faculty of Science, University of Peradeniya Introduction Simulation models are logical descriptions of the interrelationships among elements of a decision problem or the sequence of events that occur in a system over time. The major advantage of a simulation model is its ability to incorporate uncertainty in one or more input quantities. It captures probabilistic behavior and allows one to estimate probability distributions and key statistics such as mean, variance, etc. that cannot be derived analytically.

Due to the fluctuation of the sales according to the market demand, effectiveness of the company promotional activities, seasonal variations and competition with other suppliers, the quantity of sales in any given period is not fixed. Therefore, the company has to make an order under certain uncertainties.

This paper uses a simulation model to determine the optimal order quantity for a wholesale supplier for a certain period of time by analyzing the quantified risk involved in each demand quantity decision.

Methodology The past sales data of the item, non-woven interlining, were analyzed using the method of linear regression analysis to find an approximate quarterly sales distribution for year 2007. Furthermore, with the help of @Risk simulation package (Albright et al., 2002), the risk involved in each demand quantity was analyzed to predict the optimal stock for each quarter in 2007 which satisfies the company requirements.

Data collection and preprocessing Monthly sales data of the non-woven interlining for the past 5 years were used. Since our objective is to find the optimal order quantities for each quarter of the year 2007, the quarterly sales in the past 5 years were calculated using the collected data. Then, by categorizing these data according to the quarters, the respective quarterly sales for 2007 were obtained.

Results

Regression analysis The expected quarterly demands for each quarter in 2007 given in Table 1 were calculated with the use of the summary output obtained from the linear regression analysis method (Utts and Heckard, 2004). Next, the error in this quantity was taken to be normally distributed with mean (μ) = 0 and standard deviation (σ) = standard error obtained in the summary output given in Table 2. As shown in Table 3, the actual demand for each quarter in 2007 was taken to be the (expected demand) + (error), where error ~ N(0,σ).

Table 1. The expected quarterly demands

Quarter Exp demand Quarter 1 336931.4 m Quarter 2 296937.2 m Quarter 3 294826.7 m Quarter 4 459949.5 m

Table 2. Error for each quarterly demand

μ σ Quarter 1 0 24029.04 m Quarter 2 0 15612.01 m Quarter 3 0 29491.02 m Quarter 4 0 15196.34 m

Table 3. The actual demand for 2007

Quarter Predicted actual demand(m) Quarter 1 336931.4 + Error Quarter 2 296937.2 + Error Quarter 3 294826.7 + Error Quarter 4 459949.5 + Error


310

Simulation model With respect to the possible range for error, the actual demand will also fall into a range. Therefore, as shown in Table 4(i), Table 4(ii), Table 4(iii), Table 4(iv) and Table 4(v), a simulation model was built using the Excel

spreadsheet expressing the company sales process logically (Evans, 2000). Next, by assigning different values for order quantity and by simulating the demand values given in Table 3, the respective profit distributions were found.

Table 4(i). Cost data

Unit cost(c) Rs 20.5 Unit price(p) Rs. 23.575

Table 4(ii). 2007 demand distribution (assumed to be Normal with the following parameters)

μ σ First quarter 336926.6 m 24050.88 m Second quarter 296930.2 m 15626.32 m Third quarter 294827.6 m 29435.96 m Fourth quarter 459950.5 m 15188.3 m

Table 4(iii). Possible order quantities (xn) (in thousand meters)

(Decision variable) First quarter 250 270 290 310 330 340 350 370 390 Second quarter 230 250 270 290 300 310 330 350 370 Third quarter 190 210 230 250 270 290 300 310 330 Fourth quarter 400 420 440 450 460 480 500 470 480

Table 4(iv). Decision variable (xn)

order quantity (m) First quarter 250000 Second quarter 230000 Third quarter 190000 Fourth quarter 400000

Table 4(v). Simulated quantities

Loan interest rate (r) 0.18

Depreciation rate(d)

2% Cash balance/Budget(A) Rs 1000000

Demand

(m) Revenue

(Rs) Cost (Rs)

Bank loan (Rs)

Interest for the

loan(Rs) Profit (Rs)

First quarter 335626.1 5893750 5125000 4125000 185625 583125 Second quarter 296776.3 5422250 4715000 3715000 167175 540075 Third quarter 297992.9 4479250 3895000 2895000 130275 453975 Fourth quarter 458860.3 9430000 8200000 7200000 324000 906000 Net profit 2483175


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Mathematical model of the simulation model for the nth quarter : Let Unit cost = c , Unit price = p , Demand = Dn , Order quantity = xn , Revenue = Rn , Cost = Cn , Profit = Pn Budget = A , Amount of loan = Ln , Annual loan interest rate = r , Interest for the loan = In , Depreciation rate of the remaining quantity = d Decision variable : xn Input variables : Dn , c , p Objective : Max Pn = Rn – Cn – (In + Ln) subjected to a minimum risk , where Rn = c * min (Dn , xn) , Cn = c * xn , Ln = Cn – A , In = ( Ln * r) ÷ 4 For the year 2007 Unit cost (c) = Current unit cost + cost increment Unit price (p) = Unit cost * (1 +expected Profit percentage) Current unit cost = Rs. 20, d = 2% , r = 18% Increment in cost ~Triang (0.30 , 0.50 , 0.80 ) Expected profit percentage ~ Uniform (14.5%, 15.5%)

By analyzing the summary statistics report, sensitivity analysis report and the tornado

charts for the profit distributions, the risk involved in each order quantity was quantified and the order quantities given in Table 5 were taken as the optimal order quantities which gave a relatively high profit for each quarter in 2007.

Discussion As shown in Table 5, even with the best values for mean profit, there is a risk of getting negative profit. But these preferred outputs have a relatively a few number of influential inputs compared to the other simulations for each quarter. Also, these order quantities give a relatively high mean and a small standard deviation for the profit. Hence, the values 310,000 m, 270,000 m, 250,000 m and 440,000 m can be considered as the optimal order quantities for the non-woven interlining in the 1st, 2nd, 3rd and 4th quarters for the year 2007, respectively.

References Albright, Winston, Zappe (2002) Data analysis

and decision making with Microsoft EXCEL, Duxdury Press, 891-977.

Evans, J.R. (2000) Spreadsheets as a Tool for Teaching Simulation, Volume 1, University of Cincinnati, Cincinnati,

Utts, J.M. and Heckard, R.S. (2004) Minds on Statistics, Second edition, Thomson, 492-512.

Table 5. The order quantities with the maximum mean for the profit Quarter Simulation

No. Order

Quantity (m) Minimum of

the profit (Rs)

Mean of the profit (Rs)

Maximum of the profit(Rs)

1 4 310,000 -568242 674806.7 755428.2 2 3 270,000 -77841.7 619493.9 663760.1 3 4 250,000 -541476 560140.5 613019.3 4 3 440,000 161871.1 975908.3 1053350


312

Synthesis and Characterization of Layered Double Hydroxide (LDH)/Sugar Nanocomposites for Pharmaceutical Applications

S. Indrasekara, V. Karunaratne and N. Kottegoda*

Department of Chemistry, Faculty of Science, University of Peradeniya

Introduction Drug excipients are inert additives included in drug formulation to help in the manufacturing, administration, and adsorption processes. Typically, most of the drug excipients used in pharmaceutical industry are crystalline solids due to the high level of purity and stability in this thermodynamically stable state of matter. Although, amorphous drug excipients are preferred over crystalline materials, they are thermodynamically unstable leading to chemical instability, enhanced dissolution rates and greater hygroscopicity, (Ahlneck and Zografi, 1990).

Layered Double Hydroxides (LDHs) also known as anionic clays or hydrotalcite like materials, are a class of lamellar hydroxides that is suitable for stabilising the amorphous drug excipients. The structure of LDHs is based on the stacking of positively charged layers with hydrated anions within the interlamellar domain, (Roy et al., 2001). LDHs may act as nano fillers to enhance the mechanical, thermal and barrier properties of the parent amorphous drug matrix. In this contribution we describe the preparation, characterization and properties of nanocomposites based on MgAl-lactate LDHs and amorphous sugar precursors (sucrose and maltose), which are commonly used in pharmaceutical industry.

Methodology All reagents used in this synthesis were purchased from British Drug Company and were of analytical grade and used without further purification.

Synthesis of MgAl–lactate LDH MgAl–lactate LDH was prepared by co-precipitation method as described by Hibino and Kobayashi (2005). 50 cm3 of an aqueous solution containing Mg(NO3)2.6H2O and Al(NO3)3 .9H2O, (Mg: Al=1:3) was prepared and added drop wise to a 50 cm3 solution containing the lactate anion (Al:lactate=1:10) under vigorous stirring conditions, at 65 ºC and

pH 10, under flowing N2 environment. The resulted slurry was filtered and oven dried.

Exfoliation and refoliation 0.1 g of parent lactate LDH was dispersed in 100 cm3 of water and stirred until forms a stable colloidal solution. A few drops of the exfoliated LDH were casted on a glass plate and allowed to refoliate.

Preparation of exfoliated LDH/sugar nanocomposites 0.5 g of 5% (w/w LDH/sugar, referred to as 5% nc) was prepared by adding 0.45 g of the sugar precursor to a dispersion of 0.05 g LDH in 50 cm3 of water, stirred for 24 hrs and the product was separated by freeze drying. Sucrose (suc.) and maltose (mal.) were used as sugar precursors. Similarly 10% and 20% nanocomposites were prepared.

The products have been characterised by powder X-ray diffraction (PXRD), fourier transform infared spectroscopy (FTIR) and scanning electron microscopy (SEM) and the properties of the composite materials have been studied using thermogravimetry (TGA) and differential scanning calarimetry (DSC). Additionally, the particle size of the exfoliated LDH was studied by dynamic light scattering experiment.

Results and discussion The PXRD pattern of the parent material (Figure 1) represents a typical LDH consisting of relatively sharp and intense basal reflections at low 2θ values and broad and asymmetric reflections at high angles. The first basal reflection of the parent LDH leads to an interlayer spacing of 1.7 nm, suggesting a bilayer arrangement of the anion within the interlayer region. The formation of an LDH with lactate anion is further evidenced by FTIR, SEM and elemental analysis results. Stirring 0.1 g of the MgAl-lactate LDH in 100 cm3 of water resulted in a clear colloidal dispersion. The particle size of the exfoliated MgAl-lactate LDH is in the range 70-140 nm


313

as determined by the dynamic light scattering experiment and thus, suggests the presence of ultra fine nanolayers in the LDH dispersion. Upon solvent evaporation, dried fractions restacked forming a disorganized LDH.

Principally, the formation of nanocomposites with exfoliated clay materials is suggested by the absence of basal reflections associated with the LDH, in the PXRD patterns. Introduction of exfoliated LDH into the amorphous sugar matrixes improved the glass transition temperature of the parent sugar. The LDH nanolayers give the LDH filled nanocomposites better thermal stability than the pristine sugar due to differences in the chemical structure of the two components and the restricted thermal motion of the sugar molecules in the inorganic matrix. On the other hand, the LDH/maltose nanocomposites were stable for more than six months. However, such thermal property enhancement was not observed with LDH/sucrose nanocomposites.

Conclusions The nanocomposites prepared using maltose, are amorphous and the glass transition temperature of the composite materials, are superior to the pristine maltose. The higher degree of hydrogen bonding and the restricted thermal motions of the sugar molecules within LDH nanolayers may improve the thermal stability of the LDH/maltose nanocomposites than pristine maltose, thus stabilize the amorphous maltose by increasing the glass transition temperature. Thus, we expect this new finding may open up a new application of LDH/sugar nanocomposites as drug excipients in pharmaceutical industry.

Table 1. Glass transition temperatures (Tg) of LDH/maltose nc

Sample Tg / ºC

Amorphous maltose

5% mal-nc

10% mal-nc

43

49

50

10 20 30 40 50 60

003002

001Inte

nsity

Exfoliated LDH

Parent LDH

Figure 1. The PXRD patterns of parent and exfoliated LDH

Figure 2. The SEM images of parent LDH

10 20 30 40 50 60

20% mal-nc

10% mal-nc

5% mal-nc

Amorphous maltose

Parent LDH

Inte

nsity

Figure 3. The PXRD patterns of

LDH/maltose nanocomposites

2θ/degrees

2θ/degrees


314

Figure 4. The PXRD patterns of LDH/sucrose nanocomposites

Acknowledgements The University Research Grant is acknowledged for the financial support.

References Ahlneck, C. and Zografi, G. (1990) The

molecular basis for moisture effects on the physical and chemical stability of drugs in the solid-state, International Journal of Pharmacology, 62, 87-95.

Hibino, T. and Kobayashi, M., (2005) Delamination of layered double hydroxide in water, Journal of Materials Chemistry, 15, 653-656.

Roy, A. De., Forano C. and Besse, J. P. (2001) Layered double hydroxides. In V. Rives, (Ed.) Layered Double Hydroxides: Present and Future, New York, Nova Science Publishers, Inc.

10 20 30 40 50 60 2 θ /degrees

cry. suc.

10% suc -nc

Inte

nsity

20% suc -nc

5% suc -nc


315

Computational Efficiency of Weakly Orthogonal Spherical Harmonics in Cubed Sphere

M.A.A.M. Faham1, H.M. Nasir2* and T. Kaneshalingam1 1Postgraduate Institute of Science, 2Department of Mathematics, Faculty of Science,

University of Peradeniya2 Introduction Numerical computations in solving problems defined on the sphere suffer from many difficulties near the poles, known as the ‘pole problems’, when using spherical polar coordinate system for the spherical surface. For example, in the computation of global weather prediction models, concentrated grid points near the poles increase the amount of computations in the pole region where quantities of interest are of less important than the other parts of the globe.

Avoiding pole problems has attracted some researchers in the recent past (Nasir and Faham, 2006). Among the recent developments in this direction, one of the present authors has constructed weakly orthogonal and orthogonal spherical harmonics in a non-polar spherical co-ordinate system based on the ‘cubed sphere’ defined from the surface of a unit cube (Nasir, 2007).

Computational efficiency is also one of the main targets in spherical transforms, which has been considered for spherical harmonics in spherical polar coordinates by some researchers (MohlenKamp, 1999). In this work, more properties and results for the orthogonal and weakly orthogonal spherical harmonics on cubed sphere are established. Computational efficiency of using weakly orthogonal spherical harmonics verses its orthogonal counterpart is analyzed. The Fourier series computations using the weakly orthogonal spherical harmonics are considered. Weakly orthogonal and orthogonal spherical harmonics A set of solutions for the eigen-value problem ),()1(),( 2121 ttullttus +−=Δ , where

⎟⎟⎠

⎞∂

∂+

∂∂

+

∂∂

++∂∂

∂+

∂∂

+⎜⎜⎝

⎛=Δ

22

11

22

222

21

2

2121

22

1

22

)1(2)1(

tt

tt

tt

tttt

tts ts

and 22

211 ttst ++= , is given by

2

),(),(

l

t

nmlnm

ls

py = ,

m+n=l-1,l, where ),( nmlp are polynomials in t1

and t2 satisfying the differential equation

022)1(

)1(2)1(

22

11

22

222

21

2

2121

22

1

=⎟⎟⎠

⎞⎜⎜⎝

⎛−

∂∂

+∂∂

−−

∂∂

++∂∂

∂+

∂∂

+

pltpt

tptl

tpt

ttptt

tpt

and are explicitly given by the non-zero real or imaginary parts of

1i,i,2/)(

2/)( q)-p-(l2122

1 1

−=⎟⎟⎠

⎞⎜⎜⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛−

−+−∑ ∑= =

qpm

mp

n

nq

ttqp

lpm

qnpm

with 2mod,2mod 11 nnmm == and the subscript 2 in the summation indicates that the index variables increases with step 2.

A set of continuous spherical harmonics can be constructed from the eigen-functions for one face forming a six-tuple of functions

( ( )

( ) )⎟⎠⎞⎜

⎝⎛⎟

⎠⎞⎜

⎝⎛−⎟

⎠⎞⎜

⎝⎛

⎟⎠⎞⎜

⎝⎛=

−−−−

−−

22

1

1

2

122

1

1

2

1

t1

tt

tt

t1

21t1

tt

tt

t1

2121

,y,,y,t,ty,,y

,,y,t,ty)t,t(Y (1)

where, each component is an eigen-function. The spherical harmonics ),( nm

lY are weakly orthogonal in the sense that they are orthogonal for distinct l, but are not orthogonal among the

12 +l functions for a mode l.

Following the method of Kwon et al., (2001) with some modifications, a set of completely orthogonal spherical harmonics can be constructed from the eigen solutions in the form

1,0,),(2

)(,

21)(

, == ks

Qttz l

t

krlk

rl


316

with ),;()()( 11)()(

, λρ lqttpQ rlrlk

rkrl −

−=

where );( λlq rl− and )(krp satisfy the differential

equations 0))(()12()1( 2

22 =+−+−−+ qrlrl

ddql

dqd

λλ

λλ and

0)1()1(2)1(1

121

221 =−+−−+ prr

dtdptr

tdpdt

respectively and 212

11 )1()( tt +=ρ and )(/ 12 tt ρλ = . The polynomials )(k

rp are given by the real and imaginary parts of rt i)( 1 + and the polynomials );( λlq rl− are given by

,);(1

)(,2∑

−

=

−− =

rl

rn

nrlnlrl alq λλ

where the coefficients )(,

rlnla − satisfy

,)])(/()2)(1[( )(2,

)(,

rlnl

rlnl anrlnrlnna −

+− −+−−++−=

with

1,,4,2 rrlrln L−−−−= and r1=(l-r) mod 2. We normalize the polynomials such that the leading coefficient is .)(

, ⎟⎟⎠

⎞⎜⎜⎝

⎛−

=−− rl

la rl

rll

The orthogonal spherical harmonics are then given by the six-tuple formed by )( 2,1

)(, ttZ krl as

in (1). We define the column vector Pl of size 2l+1 of the polynomials ),( nm

lP for mode l and the column vector of polynomials Ql corresponding to the orthogonal spherical harmonics as follows:

Tllll

ll

ll

llll

ll

ll

llll

ll

ll

llll

ll

lll

PPP

PPP

PPP

PPP

],,,

;,,,

;,,,

;,,,[P

),1()4,,3()2,1(

)1,2()3,2()1,0(

)1,1()3,3()1,1(

),()2,2(),0(

11

11

11

11

−−−−

−+−−−

−+−−−

−−=

L

L

L

L

and

Tlllll

lllll

lllll

llllll

QQQ

QQQ

QQQ

QQQ

],,,

;,,,

;,,,

;,,,[Q

)1(,

)1(4,

)1(2,

)1(1,

)1(3,

)1(1,

)0(1,

)0(3,

)0(1,

)0(,

)0(2,

)0(0,

1

1

1

1

−

+−

+−

−=

L

L

L

L

where .2mod1 ll =

Each column vector of polynomials has four sets of components such that the first two sets correspond to the polynomials of degree l, while the second two sets correspond to the

polynomials of degree l-1. The order of the column vectors is chosen so that their relations have a simple structure. The column vectors of the weakly orthogonal and orthogonal spherical harmonics are then given respectively by

2/

PY lt

ll S

= , 2/

QZ lt

ll S

= .

Linear relations:

We find that the relationship between the two set of polynomials is given by

∑ ⎟⎟⎠

⎞⎜⎜⎝

⎛−−

−−=

−

=

−−−

−

rl

rn

nnll

nnrl

rlrl Pnrl

nlQ

1

),(2)0(, 2/)(

2)1(21 and

∑−

=

−−−−

− ⎟⎟⎠

⎞⎜⎜⎝

⎛−−

−−

−=rl

rn

nnll

nnrl

rlrl Pnrl

nlnl

rQ1

),1(2)1(, 2/)(

2)1(2

1

where 1,0,)(, =kQ krl are orthogonal polynomials

of degree l and l-1 respectively. In matrix form, we can write lll PTQ = and hence for the spherical harmonics

lll YTZ = (2)

Linear relations among functions in the Six faces Since each function in the six-tuple are eigen-functions of the Laplace-Beltrami eigen-value problem, each term is linearly related by functions defined on one face. To find these relations, we first derived the relation between

),( 21),( tty nm

l and )t/t,t/1(y 121)n,m(

l ,

),t,t(yi2/)mm(

2/)qnmm(

tt,

t1y

21)q,qm-l(

l)qm-l(n

nq 1

12

1

2

1

)n,m(l

11

1

−−

=∑ ⎟⎟

⎠

⎞⎜⎜⎝

⎛−

−+−=

⎟⎟⎠

⎞⎜⎜⎝

⎛ where

llnm ,1−=+ . Relations for the functions in the six-tuple can then be obtained in view of the symmetric properties. The components of the six-tuple are then can be calculated. Inner product The norms of the orthogonal system of spherical harmonics are given by

⎩⎨⎧

=>

+−+=

+

0,20,

)!()!()!(

122 2122)(

, rr

rlrll

lZ

rkrl π

π (3)

Fourier series The Fourier series of a spherical function f(t1; t2) is written in terms of the weakly orthogonal spherical harmonics as


317

ll

lAttf Y),(0

21 ∑=∞

=

where Al is a row vector of size 2l + 1 of coefficients given by 1

l Y,YY, −= lll fA , where

llT

ll TT 1l

1l Z,ZY,Y −− = by the use of (2).

We note that the vector of coefficients Al is easily computable since the inner product matrix involving Zl is diagonal and hence its inverse is obtained directly by the reciprocals of the inner products of )(

,k

rllZ − in (3).

Computational efficiency Computations of the Fourier series representation of spherical functions involve truncation of the Fourier series to a finite series and computing it at discrete points. Computing the Fourier coefficients ⟩⟨ ),(, nm

lYf is also done by quadrature rules that require evaluation of the spherical harmonics at discrete points. Here, we see that computing weakly orthogonal spherical harmonics for a direct computation of discrete spherical harmonics requires less than 3 percent of total computational and storage cost.

Conclusions We have established the linear relation between weakly orthogonal and orthogonal spherical harmonics. Hence, it is concluded that use of

weakly orthogonal spherical harmonics is computationally cheaper than using its orthogonal counterpart. We also derived the linear relations between the eigen-functions in the six-tuple. Finally, norm of the spherical harmonics is found.

Acknowledgements This research was partially supported by the Peradeniya University research grant (RG/2006/48/S).

References Faham, M.A.A.M. and Nasir, H.M. (2006)

Orthogonal spherical harmonics in cubed spherical Coordinates and applications to poisson equation in 2-sphere, Proceedings of the PURSE, University of Peradeniya.

Nasir, H.M. (2007) Spherical harmonics transform in a non-polar coordinate system and application to Fourier series in 2-sphere, Mathematical Methods in the Applied Sciences, John-Wiley, 30(14), 1843-1854.

Kwon, K.H., Lee, J.K. and Littlejohn, L.L. (2001) Orthogonal polynomial eigenfunctions of second order partial differential equations, Transactions of the Mathematical Society, 353(9), 3629 3647.

MohlenKamp, M.J. (1999) A fast transform for spherical harmonics, Journal of Fourier Analysis and Applications, 5, 159-184.


318

Preliminary Investigation of the Liquid Crystal Behaviour of β-sitosteryl-β-D-glucopyranoside

G.L.A.D. Liyanage, A.D.L.C. Perera and D.N. Karunaratne*

Department of Chemistry, Faculty of Science, University of Peradeniya Introduction Glycolipids are a very important class of molecules having liquid crystal properties which are abundantly found in biological membranes. Although most glycolipids seem to show liquid crystal properties, their liquid crystalline behaviour is not well understood. Liquid crystals are a state of matter that has properties between those of a conventional liquid and those of a solid crystal. For instance, a liquid crystal may flow like a liquid, but the molecules in the liquid are arranged and /or oriented in a crystal like way (Wikipedia). Carbohydrates are a new, but a very important source for liquid crystals (Vill et al., 1998). Normally, mono-, di- and oligosaccharides substituted with an alkyl chain having more than six carbon atoms show liquid crystal properties. Their amphiphilic nature leads to the formation of liquid crystals via microphase separation (Smits, 1969). β-sitosteryl-β-D-glucopyranoside is found to occur naturally in some plants (Vill et al., 1998). The commercial potential of the use of this compound as a liquid crystal has not been investigated. In this study, we attempted the synthesis of β-sitosteryl-β-D-glucopyranoside starting from glucose and β-sitosterol via Koenigs-Knorr synthesis. Its thermotropic liquid crystalline properties were investigated using polarizing microscopy. It was found that, this glycolipid has hexagonal columnar phase.

Materials and methods D-glucose was purchased from Seelze-Hannover Ltd. and β-sitosterol was purchased from Koch-Light Laboratories Ltd. All reagents used were of Analar grade. Identification of the optical texture was done using a polarizing light microscope and the determination of phase transitions was done using a temperature controller.

Synthesis of β-D-glucose pentaacetate A mixture of D-glucose (10 mmol, 1.8 g) and acetic anhydride (60 mmol, 5.75 cm3) was stirred at 0 °C while adding one drop of sulphuric acid in 5 cm3 of acetic anhydride.

Dichloromethane (50 cm3) was added, stirred for three hours and the dichloromethane layer was removed using a separating funnel. The crude product (2.170 g, 55.69%) was obtained after washing, drying and evaporating the organic extract. Finally, the residue obtained was recrystallized from ethanol (1.675 g, 42.95% , m.p. 85-105 °C).

Synthesis of Tetra-O-acetyl-β-D-glucopyranosyl chloride β-D-glucopyranose pentaacetate (5 g) was reacted with crushed anhydrous aluminium chloride (1.8 g) in chloroform. Dry benzene (50 cm3) and dry silicic acid (1.25 g) were added, filtered and the precipitate was washed with benzene (6.25 cm3). The product was recrystallized using a 1:1 mixture of ether and pet ether. (1.200 g. 25.44%, m.p. 93-95 °C).

Synthesis of β-sitosteryl-2, 3, 4, 6-tetra-O-acetyl-β-D-glucopyranoside β-sitosterol (2.180 g), tetra-O-acetyl-β-D-glucopyranosyl chloride (1.105 g), finely powdered silver oxide (0.75 g) and powdered anhydrous calcium sulphate (1.25 g) in ether were stirred for 24 hrs at room temperatrue. The solids were removed by filtration and ether was evaporated. Washing with cold methanol yielded pure β-sitosteryl-2,3,4, 6-tetra-O-acetyl-β-D-glucopyranoside in the crystalline form (0.766 g, 33.6%, 131.7 °C). The product was checked for mesogenic properties.

Synthesis of β-sitosteryl-β-D-gluco-pyranoside β-sitosteryl-β-D-glucopyranoside was synthesized by the deacetylation of β-sitosteryl-2, 3, 4, 6-tetra-O-acetyl-β-D-glucopyranoside using excess sodium methoxide in methanol and dichloromethane (1:1, 2.5 cm3). The product (0.056 g, 72.72%) was checked for mesogenic properties.

Results and discussion In a thin liquid crystal sample placed between two crossed polarizers under an optical microscope, a variety of textures and


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birefringence colors can be observed. A thermotropic hexagonal columnar phase was observed on cooling β-sitosteryl-2, 3, 4, 6-tetra-O-acetyl-β-D-glucopyranoside, after it was heated to melt (Figure 1).

Figure 1. Texture of β-sitosteryl-2, 3, 4, 6-tetra-O-acetyl-β-D-glucopyranoside in the thermotropic hexagonal columnar mesophase under crossed polarizer and analyzer

The compound β-sitosteryl-2, 3, 4, 6-tetra-O-acetyl-β-D-glucopyranoside started to melt at 131.7 °C. When cooling, it started to solidify at 127 °C forming the hexagonal columnar phase. This texture was clearly observed when the temperature was around 28 °C.

Although the compound appears to be solid at room temperature, it can exist in the liquid crystalline phase due to super cooling on the cooling cycle, and the transition from the anisotropic liquid crystalline phase to crystalline solid may occur below ambient temperature.

This molecule consists of a rigid moiety which is also called as mesogenic core (sugar group) to which several flexible alkyl chains are connected. Such kind of molecules have the ability to form discotic liquid crystals which can be stacked into columns (Figure 2). According to the texture obtained under polarizing light microscopy, the compound synthesized in this study seems to arrange in a hexagonal array forming hexagonal columnar phase.

Conclusions The glycolipid synthesized via Koenigs-Knorr synthesis has thermotropic liquid crystalline properties.

Acknowledgements

The authors thank the University of Peradeniya for providing funding for this work. (RG/2006/50/S).

References Jimmy, W. and Larry, S. Wikipedia: The free

encyclopedia [online], Available at; http://en.wikipedia.org/wiki/Liquid_crystal [Accessed 10 September 2006].

Smits, E. (1969) The sweet world of liquid crystals: the synthesis of non-amphiphilic carbohydrate-derived liquid crystals, [online]. Groningen, University of Groningen, Available at: http://dissertations.ub.rug.nl/faculties/science/1998/e.smits/ [Accessed 21 July 2006]

Vill, V., Demus, D., Goodby, J. and Gray, G., (1998) Handbook of Liquid Crystals. LCI [online]. 1(2A,2B), p.3. Available at: http://liqcryst.chemie.uni-hamburg.de/lcionline/article/oldarticles/article_0698/article_2.htm [Accessed 4 November 2006].

Figure 2. Schematic diagram of side view of the 2D array of hexagonal columnar mesophase


320

Equilibrium Studies on Cadmium (II) Interactions with Aspirin and Vitamin C in Aqueous Medium

H.H.M.C.U. Herath and C.V. Hettiarachchi*

Department of Chemistry, Faculty of Science, University of Peradeniya Introduction Cadmium has been recognized as a toxic metal and can be poisonous to human beings, because it can directly influence the metabolic processes in the body. Cadmium, in various ways, can enter and accumulate in different body parts like kidney, liver, bones, etc. during the life time, as it has an exceptionally long biological half-life. Short-term exposure to moderate concentrations (200-500 μg/m3) of freshly generated cadmium fume during less than 1 hour can cause symptoms similar to those of the metal fume fever. (www.euro.who.int) Though, cadmium toxicity in low levels can cause breathing difficulties, cough, fever and pains in body joints etc., accumulation of cadmium in very high concentrations in the body can cause renal failure, cancers, weakened immune system, anemia etc. (Kain and Schwederski, 1994)

Some of the drugs among analgesics, stimulants, and antibiotics, and vitamins have been identified as chelating agents, because of their ability of being good ligands. Although we take these drugs and vitamins to be healthy, they can form complexes with the metals in the body fluid as well. However, the conditions such as pH range, ionic strength and the temperature control the formation of stable complexes between ligands and metal ions. Aspirin and vitamin C are very popular and frequently bought drugs over the counter without medical prescription for the symptoms that are similar to those of cadmium toxicity and it is also possible that vitamin C can come from natural vegetables and fruits to our bodies.

The main objective of this research was the investigation of the interactions in cadmium-aspirin, cadmium-vitamin C and cadmium-Aspirin-Vitamin C complexes under physiological conditions.

Materials and methods Calvin type pH titrations were carried out using a Biochrom C18 pH meter. The mixtures

containing ligands (weak acids) and metal solutions in various concentrations and ratios were titrated against standard sodium hydroxide solutions in the presence of a strong acid (HCl) at a constant temperature (37.0 ± 0.2) ºC. Sodium chloride was used to maintain the constant ionic strength (0.15 mol dm-3) in the reaction mixture which ensured constant activity coefficients. Each reaction mixture contained a constant volume (20.00 cm3) in the beginning of the titration. When [A-] and ñ were calculated to obtain average log K1 and log K2 values for each binary and ternary complex, volume change was corrected at each point. The equations given below were used for the calculation of stability constants (Irving and Rossotti, 1953).

( )[ ] typeMLforAn~1

n~K 11 −−=

( )[ ] typeMLforAn~2)1n~(

K 22 −−

−=

[A-] = Free ligand concentration in the reaction medium.

ñ = average number of ligand molecules bound to the metal ion.

K1 and K2 = stability constants.

Results and discussion Table 1 reveals the summary of the most important results. However, when the ligand and metal concentrations were 1.0 × 10-4 mol dm-3 and 0.5 × 10-4 mol dm-3, respectively, both vitamin C and aspirin did not form complexes under any acidic conditions.

When both ligands were present in the reaction mixtures, either in 1:1 or 1:2 or 2:1 ratios with different metal concentrations (0.5 × 10-4 – 1.0 × 10-2 mol dm-3), ternary complex systems of


321

MLX type were formed via either ML or MX binary complexes. In the statistical comparison of the stabilities of ternary systems over binary systems, it was found that the formation of ternary complexes was much more stable than that of binary complexes at all concentration conditions, as the values of Δ log Km were greater than - 0.6, the reference value (Sigel, 1975).

Conclusions Both aspirin and vitamin C alone and together can be chelated with trace amounts of cadmium under physiological conditions. The results explain that there is a higher possibility of forming more stable ternary complexes in this environment. According to these results, it can be suggested that vitamin C and aspirin together in suitable concentrations be used to

remove toxic cadmium in the body by forming more stable cadmium – aspirin – vitamin C complexes which are water soluble and hence they can be excreted from the body.

References Irving, H and Rossotti, H. S. (1953) Journal of

Chemical. Society, 3397-3405. Kain, W. and Schwederski, B., (1994)

Bioinorganic Chemistry: norganic Elements in the Chemistry of Life,. Chichester, UK: John Wiley and Sons.

Sigel, H. (1975) Angewante Chemie, 14, 394-402.

www.euro.who.int/document/aiq/6_3cadmium.pdf

Table 1. Summary of results

pH range

[HCl]/ mol dm-3

[Aspirin]/ mol dm-3

[Vit. C]/ mol dm-3

[NaOH]/ mol dm-3

[Metal]/ mol dm-3 log K1 log K2

2.9 – 6.5 7.7 – 11.0

1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 0.5 × 10-2 4.1 3.8

3.0 – 6.2 8.4 – 10.8

1.0 × 10-2 1.0 × 10-3 1.0 × 10-2 0.5 × 10-3 4.4 3.9

3.9 – 6.7 7.7 – 11.0

1.0 × 10-3 1.0 × 10-2 1.0 × 10-2 0.5 × 10-2 6.9 5.6

4.1 – 6.3 9.8 – 10.0

1.0 × 10-3 1.0 × 10-3 1.0 × 10-3 0.5 × 10-3 4.3 4.7

4.2 – 6.1 7.4 – 11.2

1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 0.5 × 10-2 7.0 7.1

4.3 – 7.0 7.3 – 11.2

1.0 × 10-2 1.0 × 10-3 1.0 × 10-2 0.5 × 10-3 4.3 3.4

5.3 – 7.2 7.7 – 11.0

1.0 × 10-3 1.0 × 10-2 1.0 × 10-2 0.5 × 10-2 5.5 5.2

3.9 – 7.2 7.4 – 10.2

1.0 × 10-3 1.0 × 10-3 1.0 × 10-3 0.5 × 10-3 5.3 4.6

3.9 – 6.2 8.2 – 9.1

1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 7.0

8.5

3.5 – 8.5 8.9 – 9.8

1.0 × 10-2 1.0 × 10-3 1.0 × 10-3 1.0 × 10-2 1.0 × 10-3 6.8 7.1

3.1 – 6.1 6.6 – 9.8

1.0 × 10-3 1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 1.0 × 10-2 6.6

7.1

3.8 – 5.8 6.0 – 9.0

1.0 × 10-3 1.0 × 10-3 1.0 × 10-3 1.0 × 10-3 1.0 × 10-3 7.4 8.7

6.0 – 7.6 8.0 – 9.2

1.0 × 10-3 1.0 × 10-4 1.0 × 10-4 1.0 × 10-3 1.0 × 10-4 3.5

3.5


322

Attempted Synthesis of a Glucofuranose Derived Carbohydrate Liquid Crystal

L.S. Widanapathirana, A.D.L.C. Perera* and D.N. Karunaratne

Department of Chemistry, Faculty of Science, University of Peradeniya Introduction Liquid crystal state is a distinct state of matter observed between the crystalline solids and isotropic liquids. Carbohydrates are an innovative and promising source for the synthesis of liquid crystals as they have easy accessibility and availability, less toxicity, degradability, chirality, low melting temperatures, good solubility in water and organic solvents and clearly defined thermotropic and lyotropic mesophase behavior (Vill, 1998). Mono-, di- or oligosaccharides substituted with one or more alkyl chains containing more than six carbon atoms can create structures with very promising liquid crystal properties. The sugar moieties can be cyclic or acyclic but should have several free hydroxyl groups. The alkyl chain can be linked to the carbohydrate moiety directly or via an ether, thio ether, ester, amino, amide or glyceryl linkage (Smits, 1969). Selective acylation of sugar derivatives is of increasing importance in the field of carbohydrate liquid crystal chemistry. Herein, the synthesis of 3-O-decanoyl-1,2 : 5,6-di-O-isopropylidene-α-D-glucofuranose by the selective acylation of diacetone glucose with a non-traditional acylating agent decanoyl chloride as well as the synthesis of 3-O-decanoyl-α-D-glucopyranose and the investigation of liquid crystal properties of each is presented.

Materials and methods Glucose was purchased from Seelze-Hannover Ltd. and decanoic acid was purchased from Searle Company. All solvents were of Analar grade. Identification of optical texture was carried out using a polarizing microscope. Phase transitions were observed using the temperature controlling device.

The following reaction scheme was utilized for the synthesis of 3-O-decanoyl-α-D-glucopyranose.

1) Synthesis of diacetone glucose

2) Synthesis of decanoyl chloride + + 3) Synthesis of 3-O-decanoyl-1,2 : 5,6 -di-O-isopropylidene-α-D-glucofuranose + 4) Synthesis of 3-O-decanoyl-α-D-glucopyranose

Results and discussion The compound 3-O-decanoyl-1,2 : 5,6-di-O-isopropylidene-α-D-glucofuranose is a furanose sugar with a long non-polar side chain connected to the rigid polar core via an ester linkage, which is the requirement to form a lyotropic liquid crystal. It shows microphase separation (Figure 1(a)). With chloroform, which is non-polar, inverted micelles may be formed. Increasing concentration of the compound may assemble the inverted micelles one on top of the other in columns, which are packed parallel on a two-dimensional lattice having a hexagonal symmetry (Figure 2). Thus,

D-glucose

Dry acetone Anhydrous CuSO4

Room temperatureStir 30 hours Diacetone glucose

1. SOCl2 75 oC/ Reflux

2. Fractional distillation Decanoic acid Decanoyl chloride

0 0C

Decanoyl chloride

Dry pyridine

HCl SO2

HCl

0.1N H2SO4 70-80 0C 3 hours


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the phase comprises of orientational order as well as some positional order.

(a) (b)

Figure 1. Texture of 3-O-decanoyl-1,2 : 5,6-di-O-isopropylidene-α-D-glucofuranose in the (a) lyotropic hexagonal columnar mesophase (b) thermotropic hexagonal columnar mesophase at room temperature under crossed polarizer and analyzer.

Thermotropic liquid crystal properties were observed by heating a small amount of the sample in a temperature controlling device. The solid melts immediately to an isotropic liquid on heating (117-124 °C), yielding a colorful texture which might correspond to a hexagonal columnar phase, on cooling (55.7 °C) (Figure 1(b)). The texture remained unchanged even at room temperature. Thus, although the compound appears to be solid at room temperature, it may be super cooled and the transition from anisotropic liquid crystalline phase to crystalline solid phase may occur below ambient temperature.

Figure 2. Schematic diagram of a cross section of the two-dimensional array of hexagonal columnar

mesophase with inverted micelles (Daoud, 1998)

The deprotection of 3-O-decanoyl-1,2 : 5,6-di-O-isopropylidene-α-D-glucofuranose yields 3-O-decanoyl-α-D-glucopyranose. Here, no liquid crystal phases were observed.

Conclusions The carbohydrate liquid crystal 3-O-decanoyl-1,2 : 5,6-di-O-isopropylidene-α-D-glucofuranose was shown to form a lyotropic hexagonal columnar phase with chloroform, as well as a thermotropic hexagonal columnar phase. According to the polarizing microscope studies, the product may be an amphotropic liquid crystal.

Acknowledgements The authors thank the University of Peradeniya for providing funding for this work (RG/2006/50/S).

References Daoud, M. (1998) Matter diffusion in

hexagonal columnar phases. Brazilian Journal of Physics [online], 28. Available at: http://www.scielo.br/scielo.php?pid=S0103-7331998000400005&script=sci_arttext [Accessed 1 June 2007].

Smits, E., (1969) The sweet world of liquid crystals: the synthesis of non-amphiphilic carbohydrate-derived liquid crystals [online]. Groningen, University of Groningen. Available from: http://dissertations.ub.rug.nl/faculties/science/1998/e.smits/ [Accessed 11 July 2006].

Vill, V. (1998) Carbohydrate Liquid Crystals. LCI [online]. Available at: http://liqcryst.chemie.uni-hamburg.de/lcionline/article/oldarticles/article_0698/article_2.htm [Accessed 4 September 2006].

FACULTY OF ARTS


325

Geography in Practice: ‘Conceptualizing Space’ in Print Media in Sri Lanka

S.K. Hennayake and N. Hennayake*

Department of Geography, Faculty of Arts, University of Peradeniya Introduction The objective of this paper is to explore how spaces are produced and reproduced in the print media and to understand the implications of this process. In modern society where spatial friction over information flow has all but ceased, the print media plays a key role in taking messages across the entire spectrum of society quickly and effectively. In literate and politically attuned societies like Sri Lanka, print media inspires as well as prejudices people into conceptualizing spaces in various forms and certain ways. At one level this is done intentionally for politico-ideological reasons through carefully defined and orchestrated propaganda and manipulative mechanisms and at another level it occurs inadvertently as a ceaseless of process involving repetitive use, interpretation and reification of spaces in the print media.

All spaces are socially constructed. People are phenomenologically involved in this process as their social, cultural and political life is intimately embodied in various spaces. Or in other words, people are involved in this process because spatiality is a fundamental fact of life. Although people are born into certain spaces, during the course of life, they, through the process of structuration, are constantly engaged in making and unmaking these spaces first by interpreting and reinterpreting them and second by both intentional and unintentional uses of these spaces.

Print media plays a significant role in this process of social construction of space. In day to day news coverage as well as in detailed news reports, feature articles and editorials etc., a variety of spaces are referred to; existing spaces may be reinterpreted and, most of all, new spaces may be constructed. A spatial category that is used, for example, in a political speech, may gain popularity and acceptance due to the prominence given to it in the media.

A variety of spaces are made and unmade in the print media and they can be identified in several categories such as political (e.g. state, provinces, uncleared areas), economic (e.g.,

backward regions and cities), cultural (e.g., heartlands) and social (safe havens, refugee camps) etc. These spaces once ingrained in the minds of people can get re-transmitted through the political system into the decision-making process, leading towards substantive material impacts. The differential treatment of spaces in this process can further fortify and/or tear off spatial uniqueness and inequalities.

Methodology This research has attempted to identify various abstract spatial concepts publicized in the Sri Lankan dailies and weeklies through a content analysis. They are grouped according to their political, economic, cultural and social meanings. Spaces that appear to be prominent among them in the print media coverage are subjected to in -depth analysis tracing their origin and extent. This is followed by a detailed critical analysis to ascertain the ideological groundings, reflecting on the potential political implications of these concepts and how they manipulate the imagination of the people.

Discussion What is clear from the content analysis is that newspapers are not innocently reporting events taking place in spaces; rather they are responsible for the making and unmaking of these spaces leading towards significant impacts. For example, “border village” as a new space which emerged with the ethno-political conflict was publicized in the print media to such an extent that people no longer question whether such a space actually exists or not. The “boundary village” is now replaced by yet another space, “threatened village” in the recent times. Spaces such as “traditional homeland”, “cleared and uncleared areas”, “northern-eastern region”, “south”, “poverty pockets” etc. are all constructed within particular political or economic contexts, and they are reproduced and added to everyday vocabulary through the print media. While these are politically constructed spaces in the context of changing political, economic and security situations, they have gained currency through print media publicity ascertaining the


326

fact that conceptualizing space is as much a political as a social process.

Repeated use of such spatial categories in the print media allows them to be accepted as ‘normal’, ‘given’ spatial entities. Thus, the mere fact that certain spaces are frequently used in the print media can itself be a plausible factor of their reproduction. The important point that should be highlighted here is that such frequent use can ascertain an existence that a particular space does not actually have and policy decisions can be made on that basis.

Further, it appears that not only the frequent and repeated usage, but also uncritical usage of such spaces in the print media and their unquestioned acceptance by the readership/audience can also produce similar

effects as mentioned above. In other words, certain spaces are used in the print media without any critical inquiry about the origin of such spaces or any evaluation about their potential social and political ramifications. Such uncritical endorsement of spaces fundamentally conceals the fact that these spaces are, by all means, contested spaces. The repeated and frequent use together with the uncritical usage of space within the print media thus allows them to be considered as unproblematic spatial categories. We thus conclude that making decisions based on uncritically publicized spaces and by implication disregarding their contested nature, may lead to further social and spatial consequences.


327

Preparation of a Zoning Plan for the Madu Ganga Special Management Area

E. Vidanapathirana1*, P. Wickramagamage2 and S.P. Nishshanka3

1Postgraduate Institute of Agriculture, 3Department of Crop Science, Faculty of Agriculture, 2Department of Geography, Faculty of Arts, University of Peradeniya

Introduction The Madu Ganga estuarine lagoon is famous both nationally and internationally due to its aesthetic value and rich biodiversity. It is located in Balapitiya and Karandeniya Divisional Secretary’s Divisions. Four previous studies related to Madu Ganga can be identified. The wetland site report prepared by the Central Environmental Authority (CEA) in 1997 (CEA and EUROCONSULT, 1997) was the first extended study on this. In 1997, the Special Area Management (SAM) Plan for Madu Ganga estuarine lagoon was done by a management committee to develop an integrated management approach to conserve Madu Ganga. IUCN, Sri Lanka carried out a systematic assessment on biodiversity for safeguarding ecological functions, resources and values of Madu Ganga estuary for conservation and future sustenance of bio-diversity (Bambaradeniya et al., 2002) In 2002, Central Engineering Consultancy Bureau (CECB) conducted a study to identify the process that results in the formation of sand bar in the lagoon mouth (CECB, 2003). Many of these studies (SAM Plan 1997, Bambaradeniya et al., 2002) have pointed out the necessity of the preparation of a zoning plan for better management of the SAM. Coastal Resource Management Project (CRMP) has recognized zoning as a strategy for the protection and enhancement of this site.

The general objective of this study was to prepare a zoning plan for Madu Ganga SAM based on environmental principles and stakeholder views obtained through stakeholder consultation. The specific objectives are to guide development activities within the socio-cultural context and in a sustainable manner, to conserve ecologically important natural habitats and to improve economic potential of the estuary and surrounding area.

Methodology In this study, primary, secondary and tertiary data were used. Geographical Information System (GIS) and remote sensing information were considered as primary data which played

a vital role. 1:10,000 topographic maps of the Survey Department (2001) were used and those were updated using geometrically corrected satellite imageries (IKONOS images, 2005). This paper explores the application of fuzzy set theory in Multi Criteria Decision Making (MCDM) and GIS for zoning. These techniques were used for demarcating the most compatible zoning map according to the critical issues of the study area. The criteria used were 1) environmental protection, 2) flood retention, 3) economic development, 4) socio-cultural importance and 5) residential suitability which were selected using an extensive literature survey and field work.

Using expert knowledge and stakeholder consultation, criteria maps were produced by ranking. Using a pair-wise comparison matrix following the analytic hierarchy process, weights for each criterion were calculated.1 to 9 ranges were used for weighting. Nine implies extremely important and one implies the least important. In accordance with the level of importance, weights were given by expert judgment comparing a pair of criteria at a time. The weighted value of each criterion was multiplied by ranks of each map layer. The maps were created for each criterion using new values. Then, polygons with the highest one third of each criterion were separated using a query process. The final zoning map was created by union of separated areas of each criterion map.

Results and discussion According to the selected criteria, a zoning map with five zones was produced with recommendations for each one. Zones are protection, flood retention, economic, residential and socio-Cultural (Figure 1). If adequate time and financial resources were available it would have been possible to refine or further subdivide this zoning plan. This is a limitation of this study.

The zoning plan identified series of zones with various restrictions and permitted activities. The Madu Ganga estuary and its mangrove


328

Figure 1. The Zoning map for Madu Ganga SAM

covered border area were defined as Protection Zone. Since it is sensitive, the highest conservation value should be given. Especially mangrove area in north eastern part of the estuary should be strictly protected and access restricted to permit holders only. The estuary can be used for recreation and eco-tourism purposes with a certain amount of restrictions. Motor boats should not be permitted to go closer to the mangrove vegetation.

The buffer area between the lake and the upland unit comprises the Flood Retention Zone. This zone is subjected to flooding due to constriction of the mouth of the estuary by the formation of a sand bar. This is a very sensitive area and there is a need to prevent all constructional activities. Economic Zone consists of agricultural lands, commercial and service centers.

Cinnamon cultivation is prominent among upland crops in this area and there is considerable demand for this in the market. The excessive use of agro-chemicals in cinnamon plantation should be restricted to protect water quality in the Madu Ganga

estuary. Soil conservation methods should be mandatory for upland agricultural lands.

In the Socio-Cultural Zone, there are many ancient Buddhist temples, churches and a mosque. It is possible to improve eco-tourist activities without harming the socio-cultural values of this area. The Residential Zone consists of the habitat of local population and areas which are potential for expansion of habitats in the future.

Conclusions and recommendations According to the overall findings, the following recommendations can be presented to facilitate sustainable use of Madu Ganga estuary. They are establishing a single policy formulation institutional structure covering Madu Ganga SAM, establishing an information centre within Madu Ganga SAM for educational and awareness activities and integrating local people in planning and monitoring activities of conservation area. If more detailed information is available, more refined zoning maps can be developed using the same methodology. There is a possibility of further subdivisions of these zones using the participatory GIS approach by integrating local knowledge.

References Bambaradeniya, C.N.B., Ekanayake, S. P.,

Kekulandala, L.D.C.B., Fernando, R.H.S.S., Samarawickrama, V.A.P. and Priyadharshana, T.G.M. (2002) An Assessment of the status of Biodiversity in the Madu Ganga Mangrove Estuary, IUCN, Colombo.

CEA and EUROCONSULT (1997) Wetland site report conservation management plan: Maduganga Estuary, CEA, Colombo.

CECB (2003) Engineering Study on the Feasibility study on the preventing the formation of sand bar at the outlet of the Maduganga, CRMP.

SAM Plan (1997) Special Area Management Plan for Madu Ganga Estuarine Lagoon, Madu Ganga Lagoon Special Area Management Committee and Coordinating Committee, Colombo.


329

Virtual Peradeniya :A GIS System for the University of Peradeniya

R. Alagan*, D. Weragodetenne, U. Jeyaraman and C. Premaratne

Department of Geography, Faculty of Arts, Center for Environmental Studies, University of Peradeniya

Introduction Geographic Information System (GIS) matters, and currently universities, businesses, governments, schools and hospitals, nonprofit organizations, and natural resource management experts are taking advantage of it. Today, all around the world, people and institutions are working more efficiently and effectively because of GIS. Information that was limited to offices, spreadsheets, and databases is being unleashed in new and exciting ways all using the GIS. Currently, traditional cartography has been motivated into “Virtual GIS” to explore the environment more efficiently and support spatial decision-making more vigorously.

The combination of GIS and remote sensing (RS) provide a virtual model to Peradeniya University. The digital mapping exercise emphasizes the potential of remote access to Peradeniya University resources for undergraduates, graduates, parents, well-wishers, local and international communities. Using historical maps and modern geo-informatics technologies, land use patterns, academic departments, administrative information, and other infrastructural resources are captured and integrated within the World Wide Web (WWW) for easy access and communication to local and remote communities.

Spending nearly one year in GIS and GOOGLE EARTH methodologies, and participatory methods a group of GIS experts from the Center for Environmental Studies were able to develop this virtual model for spatial decision-making. This study will present some of the key developments of the virtual GIS stand point.

Although the value of traditional technological approaches (such as 2DGIS, cartography, survey maps, etc) have been clearly illustrated by a number of projects for Peradeniya University mapping, newer techniques in Virtual GIS offers significant enhancement to display cartographic information and solicit

input from university as well as outside communities. The ability to move toward virtual systems and to embed multimedia within an Internet GIS environment promises significant advances in publicizing and provide access to information about Peradeniya University.

This research employs Virtual GIS methodology to develop a model for Peradeniya University. In the past, there were a number of times cartographic technologies have been adapted to develop a land use map for Peradeniya University. On the one hand it is vital to appreciate the traditional mapping technologies that were used to capture the past of Peradeniya University. On the other hand these technologies are limited in their ability to facilitate spatial decision-making. In addition, it is noted that the traditional mapping technologies are static practices for dynamic decision-making. The proposed “Virtual Peradeniya University” model employed GIS on a high scale to develop land use patterns, administrative departments, information, and other infrastructural systems of the university. The digital Virtual Peradeniya University model would support the university administration to make better decisions.

Virtual GIS helps to identify university resources such as faculties and departments, staff quarters, security facilities, medical amenities, transportation networks, sports facilities, open spaces, recreational services, and other land information. The Virtual Peradeniya University project not only supports university communities but also integrates international communities who are interested in exploring this higher education facility at Peradeniya.

Case study Peradeniya University and its land premises were selected for case study. The proposed Virtual Peradeniya University model covered the entire university land premises which extend from the north (the current Dental Faculty at Peradeniya Road) to the south (to


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Mahakanda Gal-bungalow). From the east it covers the Hantana Mountain peak to the west up to the Gampola – Kandy railway line (behind the Faculty of Engineering).

Methodology Under the broad methodological approach of Virtual GIS there are five methods that have been adapted to develop the Virtual Peradeniya University. These methodologies are: 1. Introduction of the latest digital image

technology on the World Wide Web of Google Earth as base information for the Virtual University of Peradeniya.

2. Integration of Global Positioning Systems, GIS, and Google Earth for land use mapping.

3. Integration of participatory GIS approach into university land use mapping.

4. Introduction of the technology of digital image processing (GIS and Remote Sensing) for future land use monitoring.

5. Development of a Virtual GIS technology to publish Faculty of Arts and its departmental information through WWW for wider audience data access such as staff members, outsiders, international community, and students around the world using Web-GIS.

Project objectives There are a number of project objectives that were identified. These are, to: 1. Develop Virtual Peradeniya University

Maps for the Faculty of Arts to support monitoring future land-use changes, updating data of, and to enhance spatial decision-making procedures within and outside the faculty

2. Develop an integrated database with GIS for the entire university administrative system

3. Develop spatial knowledge on location of university premises and provide university community and outside community to search and explore university facilities through Web-GIS.

4. Expose Peradeniya University to a wider community through WWW.

Discussion, relevance and result of the study During the last one year four members team engaged in a variety of map development, data collection, and model development of the Virtual Peradeniya University from the Center

for Environmental Studies. This project has integrated participatory mapping method to integrate local knowledge in the Virtual Peradeniya University. The GIS mapping and participatory mapping techniques include very comprehensive spatial layouts of university land information with infrastructure conditions.

Currently, there is no GIS mapping system exist in the university to explore and access of the administrative or physical infrastructural information. The lack of spatial information on the university limits many stakeholders to participate in the correct decision-making. The study also highlights that it is not the lack of expertise or facilities which limited such model development rather it is the lack of interests and VISION of people to build such robust virtual model of Peradeniya University. Therefore, it is suggested that it is vital to develop a virtual model of the university where not only locally but also globally interested people can participate in higher education.

Result of Virtual Peradeniya University The GIS mapping project has gathered necessary basic information from diverse sources. The information includes remote sensing images using GOOGLE EARTH technology, Global Positioning System for locational information, Survey Department Maps, ground truth information from the GIS team, administrative knowledge from the university communities, university map archives, and information from maintenance department. The project developed two large scale digital maps for the wider community access and two other large scale analogue maps for university community use.

Future training and discussion It is expected to have a preliminary training and discussion with the key members from the Faculty of Arts to share ideas and comments for further development of the GIS mapping. Once we receive comments and suggestions from the Arts Faculty, then the second level project (university mapping) will be submitted to the Vice Chancellor and other senate level decision-makers’ opinions. Subsequently, with a small training session the virtual GIS mapping will be handed over to the Dean Arts and Vice Chancellor to display in the relevant buildings for public access.


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Conclusions Currently, a comprehensive GIS database and information system of Peradeniya University is limited. The lack of spatial information limits diverse stakeholders from progressive decisions about Peradeniya University. The proposed Virtual Peradeniya University is a comprehensive digital GIS database about the

university system and it has great potential to improve stakeholders to communicate and participate in spatial decision-making from different part of the world. The Virtual Peradeniya University mapping project could be a GATEWAY to a wider audience to publicize the prestigious university.


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Farmers` Perceptions Towards Climate Change and Farm Management Practices

K.W.G.R. Nianthi

Department of Geography, Faculty of Arts, University of Peradeniya

Introduction Climate change (CC) may adversely affect the water availability and management problems, thus in turn affecting agricultural production. As the Dry Zone (DZ) of Sri Lanka is a water deficit area, its agriculture is highly vulnerable to CC. The economic disruption, social dislocation and human suffering caused by drought, among DZ communities have often been described in historical chronicles. In the modern time too, almost every year, there have been media reports on rainfall failure in many parts of the country especially in the DZ. Farmers` attitudes and perceptions towards CC and adjustment of farm management practices were examined in this paper. To understand the reality of CC and its impact on the paddy community in the DZ; Kekirawa division (with 03 villages) in the Anuradhapura district was selected for this study. The main objectives of the study are; to examine the present CC and fluctuation of rainfall and temperature since 1960 and to study the responses of paddy farming communities to perceived threats of CC and its consequences. The study revealed that the study area is heavily dependent on the availability of water and timely rainfall and the dry spells are often caused by the failure of Northeast monsoon (NEM) rainfall. Such failure leads to a continuous decline in the availability of water resulting in the reduction of rice production. During the last two decades, rainfall has decreased drastically in the study area. The irrigation system consisted of 07 rain-fed tanks but these small tank systems do not protect the farmers from severe water shortages. Climatic factors have significantly affected paddy production, its extent and yield, particularly under rain-fed conditions in the field area. Due to the uncertainty of timely rainfall, there is an increasing trend on the part of farmers to engage in ‘Chena Cultivation’ than in paddy cultivation especially in the ‘Yala’ season Farmers have noted a variety of changes in climate affecting their paddy farms: including an increasing general warming of the climate with reduced rainfall and a shift in the seasonal pattern of rainfall.

Material and methods To understand the reality of CC and its impact on paddy cultivation in the DZ, a questionnaire survey was carried out with particular reference to farmers’ response to CC and its effects on communities and their livelihood systems. Discussions were also held with officers and the village communities. The 03 villages are located close each other, are small in size and have no remarkable differences among them and therefore, were analysed together with a total sample of 99 households. The sample was drawn by using the random sampling method. The field survey was carried out during the Maha season (MS) (October to March) 2003-2004. In addition to the questionnaire survey, temperature and rainfall data were collected from the Meteorology Department in Colombo and the trends and fluctuation of rainfall and temperature variation have been analyzed using linear trend analysis.

Results and discussion Currently, 07 rain-fed small tanks are functioning in the study area; but invariably there is no water in the YS in all these tanks. Therefore, none of the farmers has been able to cultivate paddy during the YS. Even in the MS, during the period of the field survey, water had dried up in all the tanks due to insufficient rainfall from NEM. Therefore, the Maha cultivation was not possible due to inadequate rainfall. The preceding YS cultivation had also failed due to inadequate rainfall. Next to paddy cultivation, shifting cultivation (Chena slash and burn cultivation) has been the main source of livelihood for paddy farmers in this area. Due to the uncertainty of timely rainfall, there is an increasing trend for farmrs to engage in ‘Chena cultivation’ than in paddy cultivation especially in the YS. None of the tanks are linked to any major irrigation schemes and therefore, water availability is vulnerable to local rainfall failure. Although almost all the farmers had cultivated paddy during the MS, the crop was completely damaged due to inadequate rainfall during the NEM. The


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farmers` perception of cc is reported to be influenced by a number of factors. The rainfall fluctuations have also affected average yields and consequent adoption by paddy farmers of poor management practices. The poor economic status of the farming families was obviously caused by the failure of crops due to weather changes or disturbances. According to farmers’ remarks, during the last two decades, rainfall has decreased drastically. Weather disturbances, warming and heat in summer have also been increasing. All the households indicated that they were very vulnerable to the failure of the rainfall and water scarcity in their agricultural activities. They do not get timely rainfall to undertake paddy cultivation during the MS. Therefore, it affects cultivation of paddy or other seasonal crops during the YS too. The reasons for non-cultivation of large tracts of paddy land during the last MS and YS, were mainly due to the uncertainty of rainfall, both Northeast and Southwest monsoons. Farmers have noted a variety of changes in climate affecting their paddy farms with increasingly erratic weather patterns, general warming of the climate with reduced rainfall and a shift in the seasonal pattern of rainfall. Particular attention should be placed on high drought -resistant crop varieties and the development of irrigation water management practices. No doubt, much of this requires a proactive position of the Government and the district administrations to enable the farming communities to come to terms with the risks involved in their chief occupations and livelihood system.

Conclusions The livelihood of paddy communities in this area is largely dependent on paddy cultivation,

based on a highly variable rainfall. The increasing temperature conditions in the last two decades were combined with decreasing rainfall during the NEM. According to farmers’ views, due to uncertainty of timely rainfall there is an increasing trend to engage in ‘Chena cultivation’ than for paddy cultivation especially in the YS. None of the tanks are linked to any major irrigation schemes and therefore, vulnerability to local rainfall has increased. Particular attention should be placed on the cultivation of drought resistant crops and the development of irrigation water supply and management practices. The dependence on rice has to be reduced and other crops less susceptible to droughts could be promoted. The elements of such a strategy should include: the development of rice varieties with high yields which are drought resistant and use less water, agricultural practices which use less water, cultivation of alternative crops and various cropping patterns. In the long term the introduction of agricultural systems which are less dependent upon the monsoon cycle may be necessary. There is also a need to promote rain-fed farming and the efficient utilization and conservation of water through the development of an integrated farming system by taking account of climate change. Finally, there is the need to create community awareness by means of farmers’ educational programmes on climate change and its possible hazards. A wide variety of adaptive actions may be taken to overcome adverse effects of climate change on agriculture at the level of farms adjustments. There is a need for revising existing agricultural policy by taking into account the impacts of climate change.


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Changing Landscape of Kandy

A.S.M. Nawfhal

Department of Geography, Faculty of Arts, University of Peradeniya Introduction The planning process of Kandy is continuing, the road frontages as well as the buildings that are listed as heritage monuments are on the verge of destruction or being defaced with modern architecture. Some buildings have already been demolished. Except the Esala Perahera, many other cultural events like Kandyan dance and handicrafts are losing their heritage value as a result of urbanization and modernization. Consequently, the entire city is under the threat of losing its heritage importance. This is a very unfortunate situation in view of the fact that every element of the city has been designed to illustrate the legacy of royal patronage extended to Buddhism for the purpose of maintaining the supremacy and the legitimacy of the rulers of the past.

Methodology Through a literature survey, a profile of the historical landscape was extracted. Data and information were collected from relevant authorities involved in planning and implementation process of the city. A comprehensive questionnaire survey was conducted to collect information from the occupants of 24 randomly selected buildings named as heritage buildings by the KMC. Additionally, samples from haphazardly developed shops were also taken into consideration. The spatial data and information of the city were processed by employing GIS technology to develop models of the lost heritage.

Changes in cityscape Kandy city has gone through several phases of change in its physical and cultural landscape. After the establishment of the Kingdom, the city was made the capital by its first king in 1592. The city landscape had been laid out by taking account of the physical features, security requirement, and also the social hierarchy of the kingdom. The cityscape at that time was unique because of the grid street layout of the city which is still visible. In addition to the Maligawa complex there were other monuments within the landscape of the sacred

area. During the time of the Portuguese and the Dutch, the city was destroyed by arson more than four times.

The British changed the face of the city by constructing buildings such as 06 schools, 05 churches, 06 company buildings, and hotels. Some old residences were changed for their administrative or trade functions. The prison complex located within the core of the city is a miniature of a fortress in Europe. In the post independence period, many houses and buildings were built in the core area without proper planning. As a result, the city centre and its surrounding areas have buildings that are not in harmony with the cityscape or not compatible with the heritage buildings.

After opening 4 main arterial roads, the flow of commodities to the city from outside increased rapidly, and it became a multi-functional urban centre. Administrative functions of missionary activities, trade or commercial functions, transactions related to tea and other local produce were expanded. British companies established their branches, hotels and restaurants, where liquor was served. Consequently, the cultural impact of the British was severely felt. All these converted the religio-political environment of Kandy into a commercial one in central Sri Lanka. The British however, preserved some of the cultural monuments like the Temple of the Tooth relic and its peripheral and traditional functions like the Perahera.

The changes that have taken place in the recent past are reflected by large shopping complexes, under-passes, commercial and bank buildings, car parks, new roads, school buildings, and other new structures. Further changes have begun to take place along new roads. The result of all these obviously change the heritage and cultural values of the façade of the road.

Kandy was declared a World Heritage city by virtue of the fact that it possesses rich cultural mixed historic buildings, monuments, structures and living traditions of the past. This can be observed from the list of 440 buildings comprising old houses, business places, office


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buildings and monuments in the core/built up area gazetted by the government. A systematically demarcated zoning plan has also been gazetted to control the pressure on land use. The need also has been recognized to protect paddy lands, unstable lands, stream and road reservations. These measures are expected to minimize the damage to the existing landscape.

The challenges ahead for Kandy city can be considered in terms of this increasing demand for services, controlling traffic, waste management and minimizing natural disasters. In order to protect and safeguard the city and its socio-cultural heritage from the internal and external pressure or modernization, careful planning is required.


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Vessagiriya: Epigraphy and Palaeography

A.M.P. Senanayake

Department of Archaeology, Faculty of Arts, University of Peradeniya Introduction This is a very important archaeological site known as Vessagiri located in the southern section of the ancient City of Anuradhapura. Inscriptions and monuments from the pre-Christian era till about the 10th century AC are found at this site. However, before the present study, this site has not been explored properly and completely. The archaeological explorations and excavations began here in 2006, under the supervision of Prof S.D.S. Seneviratne and with financial support from the Central Cultural Fund (CCF). This exploration was launched as a joint project of the CCF and the Government’s Department of Archaeology. This paper is based on the epigraphic material found during the course of the investigations of the above project.

Aims and objectives (a) Critically examining the published epigraphic records found at the site being investigated. (b) Recoding inscriptions which have not yet been published. (c) Establishing the historical significance attributable to the site. (d) Making use of the available epigraphic records on site for training university students specializing in archaeology.

Methodology A literature survey was conducted preliminarily before the ground work. The site was initially divided into 10 x 10 square grids to facilitate the investigation. Estampages were prepared for all symbols and inscriptions. At the same time, they were photographed using digital cameras. Hand written copies were also made. Finally, an interpretation was attempted on the

basis of the material found in all of the collected data.

Results It was possible to discover and record quite a number of new symbols and inscriptions found at the site. Symbols were mainly non-Brahmi in character. The number of new inscriptions was ten. Out of them, three were early Brahmi cave-inscriptions, while two belonged to 2nd century AC (After Clenit). There were also four inscriptions attributable to the 5th and 6th centuries AC. Finally there was one inscription belonging to 7th century AC.

Discussion and conclusions On the eastern side of one (rock A) of the three rocks at Vessagiriya, there appeared several non Brahmi symbols. Some of them may represent close connections with pre Buddhist rituals and they may be attributed to the Proto-historic period. The majority of inscriptions that have been found were at the rock (B), which was fully associated with architectural remains. Out of them, one inscription specially mentioned the families which arrived in Sri Lanka with the Sri Maha Bodhi.

This study enabled the investigator to edit and reinterpret the inscriptions formerly published. The estampages of all the symbols and inscriptions were made for the purpose of preserving them for future studies. There is a view that this place called Vessagiriya was no other than a part of the site known as Isurumuniya. The present investigations made under this project proved the above view which was presented by Senarat Paranavitana to be acceptable on fairly reasonable grounds.


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Characterization of Soils at the Vessagiriya Archaeological Site in Relation to Past Settlement Sites

A.M.C.P.K. Attanayake1, R.B. Mapa1* and S. Seneviratne2 1Department of Soil Science, Faculty of Agriculture, University of Peradeniya

2Department of Archaeology, Faculty of Arts, University of Peradeniya Introduction The study of archaeology is based on artifacts and ecofacts retrieved from explorations and excavations. In the past two decades environmental archaeology has come to play a crucial role in data collection and interpretation. The application of archaeological sciences has introduced the use of multidisciplinary studies in archaeology. It is in this context we wish to argue that information from soil, insects and pollen could be integrated with investigative and interpretive archaeology. When a particular human activity related to land use is carried out on the earth’s surface for a sufficient time span, it produces certain imprints on the soil. Therefore, information on past cultural activities can be complemented by analyzing soil characters that are mainly influenced by human interventions.

This paper describes a preliminary soil characterization carried out at the Vessagiriya archaeological site. The objective was to characterize soils at the Vessagiriya excavation site to relate them with past cultural events in the site.

Methodology Soil samples were collected from one of the excavation sites in Vessagiriya located at Anuradhapura. Soil samples were obtained from five layers at depths of 0 – 25 cm (D1), 25 – 37 cm (D2), 37 – 55 cm (D3), 55 – 89 cm (D4), and 89 – 170 cm (D5). Sand (diameter, 0.05-2 mm), silt (diameter, 0.002-0.05 mm) and clay (diameter, less than 0.002 mm) proportions in each layer were determined by the pipette method (Gee and Baurder, 1986). The sand fractions were oven dried and fractionated into five groups by mechanical sieving. The five groups were the particles having diameter of 1-2 mm, 0.5-1 mm, 0.5-0.3 mm (medium sand), 0.3-0.1 mm (fine sand) and 0.1-0.05mm. Fine sand / silt and medium sand / silt ratios were derived. Soils were digested with aqua regia and hydrofluoric acid

in a closed vessel to determine total P content (Hossner, 1996). Available P, occluded P in Fe, Al oxides and hydroxide and Calcium Phosphate were extracted by using standard fractionation schemes as described by Kuo (1996). Extracted P fractions were determined by the Ascorbic acid method (Kuo, 1996). Organic matter content was determined using the Walkley & Black method (Nelson and Sommers, 1996). These results were used to complement information on archeological findings.

Results The texture of soils in all five layers was sandy. Fine sand / silt and medium sand / silt ratios were different among the layers. The organic matter percentage of soil gradually reduced with depth. The maximum organic matter content was 1.2% in the D1 layer.

As shown in Figure 1, layers of D1 and D2 showed the highest total P concentration which were five times higher than the minimum in the D4 layer. In D3 and D5 there was no significant difference in total P concentrations, which were two times higher than the minimum. Table 1 shows that the D5 layer has comparatively extreme proportions of soil inorganic P fractions. Layers of D3 and D4 expressed similar signature in inorganic P fractions. The D1 and D2 layers showed similar inorganic P fractions.

Discussion Different fine sand / silt and medium sand / silt ratios indicted that the soil profile was disturbed by external factors. When the landscape evolution of the site is considered, siltation could be the most possible natural external factor. The sandy texture and the organic matter variation along the profile showed that there has been no siltation process in the past. Therefore, human influences could be the major reason for the disturbance of soil at the Vessagiriya site.


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0100200300

0-25(D1)

25-37(D2)

37-55(D3)

55-89(D4)

89-100(D5)

Depths (cm)

Tota

l P (p

pm)

Figure 1. Total Phosphorus concentrations in soil layers

Table 1. Percentage of different fractions of inorganic P in soil layers

* Easily extractable P ** Tightly bound or occluded P *** Calcium phosphate and apatite

Different levels of total P among the layers confirmed that diverse cultural phases existed in the site as interpreted by archaeologists. Varying proportions of P fractions demarcate the soil layers, which were subjected to various land use systems. Similar proportions of P fractions in D1 and D2 layers indicated that these layers were subjected to the influence of the same land use system. Similar proportions of P fractions and different total P concentrations in D3 and D4 layers indicated

that they were under the same land use system but in different intensities and durations. According to the archaeological findings D3 and D4 layers belong to the Early Iron Age dating to 1000 BC – 400 BC. The deepest layer (D5) showed remarkably different proportions of P fractions, expressing that this soil layer was subjected to different cultural phase. According to archaeologists D5 represents the Prehistoric culture that had a hunting and gathering economy. As P fixed in Fe, Al oxides and hydroxide content increases with time of soil development, this fraction of soil P can be used to determine the relative age of soils. This theory was correlated with chronological sequences developed by archaeologists using artifacts at the Vessagiriya excavation site.

In the above context, it can be shown that results of soil analysis complemented archaeological interpretations. The soil P fractionation result was a valuable tool to demarcate past cultural phases to show that the Vessagiriya archaeological site was under different human settlements at different eras.

References Gee, G.W. and Baurder, J.W. (1986) Particle-

size analysis, Methods of Soil Analysis, Part 1 and 2, American Society of Agronomy, Madison, WI, USA.

Hossner, L.R, (1996) Dissolution for total elemental analysis, Methods of Soil Analysis, Part 3, American Society of Agronomy, Madison, WI, USA, 49-63.

Kuo, S. (1996) Phosphorus, Methods of Soil Analysis, Part 3, American Society of Agronomy, Madison, WI, USA, 869-917.

Nelson, D.W. and Sommers, L. E. (1996) Total carbon, organic carbon and organic matter, Methods of Soil Analysis, Part 3, American Society of Agronomy, Madison, WI, USA.

Depths (cm) F 1 %

* F 2 %

** F 3 % ***

0 - 25 (D1) 2 74 24 25 - 37 (D2) 2 74 24 37 - 55 (D3) 7 24 69 55 - 89 (D4) 9 22 69 89 - 100 (D5) 4 83 13


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Functional Uses of Stone Outcrops at Anuradhapura Vessagiriya: An Environmental Archaeological Study

T. Wagalawatte

Department of Archaeology, Faculty of Arts, University of Peradeniya Rock formations of the earth are categorized into different types based on their natural characteristics. The rocks in Sri Lanka are also classified by geologists based on the basis of many factors. For an archaeologist, it is important to have a scientific knowledge about rocks in making logical explanations and interpretations about environmental selection of sites, historical constructions using rocks as raw material and the functional use of technologies in relation to raw material.

Vessagiriya archaeological site, which was investigated since the 19th Century, is located at the southern end of the heritage city of Anuradhapura. The central feature of the site is represented by three relatively large and scenically beautiful rock out crops, named by archaeologists as Rock A, B and C. Recent investigations indicated that the rock outcrops were used from the pre historic period. The pre historic people used it as a protective safe haven. The Early Iron Age folk used the lower outcrops as a natural foundation for their settlements. The Early Historic (3rd Century BC) devotees chiseled the rocks and carved out shelters for forest dwelling Buddhist monks. They carved out drip-ledges to prevent rain water seeping into the caves and to engrave the earliest inscriptions of Sri Lanka. The advanced period of rock usage at Vessagiriya commences from the Middle Historic period (4th to 10th Century AC). It was noted during the 2007 archaeological investigations that the ancient people had an in-depth knowledge on the physical characteristics of rocks in selecting rocks as raw material, with special reference to the built environment. A whole range of architectural art representations were fashioned out of rock during the Middle Historic Period.

Metamorphic rocks are the most abundant rocks found in Sri Lanka. Due to the pressure and temperature changes, protoliths of these rocks have been subjected to mineralogical and structural changes. Most of these rocks can be easily broken through the foliation plane which was formed from the metamorphic process. We can identify well developed foliation

planes in all of the rock outcrops at the Vessagiriya archaeological site.

The layering of rocks are formed during the metamorphic or sedimentary processes and layers are markedly shown be their different colors. Rocks having dark light colors had been used for constructions at the Vessagiriya site. For example, metamorphosed limestone was used to construct the moon-stone sandakadapahana, steps etc. This indicates that the artist had applied his knowledge and technical skills for constructions considering naturally available raw materials.

Ancient constructions of large dimensions which can be seen even today were exploited through simple techniques. These techniques were applicable, since the raw material existed in a controllable manner in the environment. For example, they made shila puwaru (stone slabs) from naturally layered rocks. A location near Rock C in the southern part of the Vessagiriya displays such shila puwaru that had been separated from the parent rock.

In order to separate the rock, it had been broken along the holes created in the rocks. This was evident by the drill holes found on the edges of the main rock. Metal equipment that were used to separate the rocks by creating pressure inside the holes were unearthed by archaeological investigations. Six of such equipment are exhibited in the archaeological museum in Anuradhapura and two are registered under Nos. C. 7.12 and C. 7.10. This method is yet utilized to break rocks. The only difference between the ancient and present practices is the use of metal pegs and chemicals to create pressure at present.

As described above, the main reason for the built environment activity around Vessagiriya area (including Isurumuniya and Ranmasu-uyana) is the availability of natural resources suitable for constructions and art representations.


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The Ecological Values Reflected in the Buddhist Vinaya (Discipline)

M. Gnanananda

Department of Pali and Buddhist Studies, Faculty of Arts, University of Peradeniya Introduction Although the object of Buddhist discipline (vinaya) is to regulate the activities of monks it also has great relevance to society especially in its involvement with the environment. Some problems that affect modern society globally, and require urgent attention are pollution and wastefulness. While pollution causes health problems, wastefulness causes poverty. These problems are aggravated when adequate attention is not paid to them. Therefore, the aim of this paper is to discuss ways and means to find a common solution to minimize some of these problems through an understanding of the vinaya rules.

Methodology A detailed study of the Buddhist discipline (vinaya) is of utmost importance to understand the impact it has had on the social and ecological aspects of life within the Buddhist fraternity. Such a study is also likely to throw new light on some problems arising from the day-to-day behaviour patterns of people in contemporary society.

Discussion Among the many things in the world, water, flora and fauna are wonderful creations of nature (Eco-world). They are supportive resources, which influence and mutually exist not only for the benefit of mankind but also for the entire organic world. Therefore, protecting these resources is a responsibility of mankind. It is mentioned in Sekhiya (a group of precepts) that persons should not pollute with human waste where there is water. Today because of the desire for development without any control, various chemicals and fertilizes are used in water and this has caused health and ecological problems. Sometimes chemical weapons are

tested in the sea, which is another major problem.

Protection of the flora and fauna enhances the beauty of nature and also promotes physical and mental healthiness. Khandhaka Vinaya explains how to maintain the senasana (sylvan abodes: dwelling of the monks) and its neighborhood in a clean and eco friendly manner. Especially Sekhiya shows the value of cleanliness. Destroying of forests is a threat to living creatures and it also causes damage to the environment and this has created secondary problems such as floods, famine and drought etc. Bhutagama Pacittiya (destroying of plants) claims that wiping out flora and fauna is prohibited for Bhikkus. Khandhaka explains that even constructing the senasana (dwelling places) should be done with care to protect the environment. In the present day, with the advancement of science and technology, the danger to the environment is obviously noticeable.

Conclusions The catupaccaya (the four basic requirements) prescribes the method of fulfilling their minimum requirement, avoiding waste and utilization of scarce resources for the benefit of mankind. Poverty is the result of socio-economic disparities and the gap between the extremes of ‘haves’ and ‘have-nots’. Although there are many causes of poverty, the maximum utilization of resources and management of natural resources is a means of overcoming poverty and wastefulness.

The Vinaya rules are very clear and helpful in solving social problems and these are provided with examples and statistical data.


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Is ‚HA a Cluster in Pali Language ?

M. Wijitadhamma

Department of Pali and Buddhist Studies, Faculty of Arts, University of Peradeniya Introduction It is obvious that the medieval Indo Aryan era inherent letter in the Pali language is the letter ¬ha written as ha by binding ¬a. When we look at it outwardly we can see it at a glance as a cluster. But in the linguistics research, it is seen as an individual letter. The objective is to inquire in to it.

Objectives and methodology Though both the letter ¬a and ¬ha can be seen in the Pali language, it does not appear in the classical Sanskrit. But there is evidence found in R®igveda that indicates it is present in the Vedic Sanskrit. Linguists say that the vowel centered ∂a is pronounced as ¬a and ∂ha as ¬ha. In the charm of “Agnim¥¬e purohitam’’ ¥¬e is created from the derivation of the root ¥∂ the letter la† lakåra åtmanepada is used as the first person singular. It’s documentary form should be ¥∂e because it is located in the middle of the two vowels (¥+∂+e) and it is pronounced as ¬a. In other instances the letter ∂ha is pronounced in the same way. In the place of ‘¥∂yo nuta nairuta’ though ¥∂yo is from the root ¥∂, it doesn’t seem that the letter ¬a is the letter o. It is not centered there. Thus the form of the letter is such. The version ‘tama ås¥t gË¬ha magre’ gË¬ha is the pronunciation of gË∂ha. Since the ∂ha is in the centre of the vowel it has became ¬ha (g+Ë+∂+a). Mac Donnell has introduced ¬ha as the aspirated letter of ¬a. This ¬a is voiced as ¬ha when ¬a and ∂ha are pronounced together. But that pronunciation isn’t received from auditory means. It is very clear from the above examples that it can be received only by means of visual media.

In the Tipi†aka written in Pali language we can find ¬ha when it is considered by way of linguistic, ∂a has become ¬ha When it was derived from ∂a. According to the characteristics of the language evolution there can be ¬ha after long or short vowel. In Sanskrit ∂ha which is followed by long vowel becomes as ¬ha in Pali.

1. After a long vowel- ∂a>¬ha

gå∂ha>gå¬ha

rË∂ha > rË¬ha

mË∂ha>mË¬ha

2. After a short vowel - ∂a>¬ha

d®∂ha>da¬ha

It can be decided as the cluster or non-cluster of ¬ha based on both of these evolutions. Specially in the Pali language, there is no long vowel before the cluster. However, we should not forget that it is used very rarely. But it can be seen that there is no such occurrence in the words given as examples from Pali. The second example shows that after the short vowel the ¬ha is used. That is the only example we come across in the Pali language. But that is the only word which expresses a meaningful idea that can’t be expressed by any other word and it is the great enlightenment that the Pali language has received. The reason for its important is that in the letter ¬ha the same vowel and its shortness decides the cluster and non cluster nature of ¬ha.

After the short letter the words of ¬ha occurring to the version of poetry when enquiring the Metre. If the letter ¬ha a cluster existing before it should be shorten. The reason for this is that it is considered as the long letter before the cluster. The long letter can be a definite long letter when there is a definite or indefinite long letter. It can not be considered as long when it is used in place of the definite long letter. When it is a short letter, it can’t be a cluster when ¬ha is used after the short letter.

Conclusions It can be proved that it is obvious, according to the features of language evolution and features of classic Metre that the letter ¬ha is not a cluster. So it can be incorporated in the traditional Pali alphabet.


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The Frankfurt School of Social Research and Critical Theory, with Special Reference to Max Horkheimer

M. Rajaratnam

Department of Philosophy and Psychology, Faculty of Arts, University of Peradeniya The main objective of this research is to explore the practical aims and contributions of the Frankfurt school, the most important and influential group of leftist intellectuals, philosophers, and social theorists in twentieth century Germany. This paper focuses on the Frankfurt school of social research and critical theory with special reference to Max Horkheimer (1895-1971), who was the Director of the Institute of Social Research of the University of Frankfurt. The Frankfurt school of social research is a school of thought and their critical theory expressed an explicit interest in the abolition of social injustice. Members of the Frankfurt school were affiliated to the Institute of Social Research which was established in 1923 and Max Horkheimer was appointed as its second Director in 1931. Max Horkheimer introduced critical theory which focuses on neo - Marxist social theory, social research, philosophy and a genuine interest in a radical change in contemporary society. No projects hold a more prominent place in the development of modern European thought than Critical theory and its practical commitment towards building a better society. Though there are numerous members - Max Horkheimer, Theodor Adorno, Herbert Marcuse, Eric Fromm, Friedrich Pollock, Leo Lowenthal, Walter Benjamin, Habermas and others who contributed to this school, this study focuses mainly on Max Horkheimer’s contribution to social research with special reference to his Traditional and Critical Theory (1937) and its distinction of traditional and Critical theory. Max Horkheimer emphasized the rejection of ‘static’ traditional methods and insisted on a new commitment to social research in a critical mode. Critical theory recognizes the historical nature of such inquiry and acknowledges the potential for ideological critique leading to social and political change. This research contributes to promote our social and political research with the genuine critique of modern society and politics in order to solve major problems in the present context.

Quantitative and qualitative methodologies are used in an integral manner in this research. Max Horkheimer’s original writings- Traditional and Critical Theory (Horkheimer, 1937) and his other major writings such as Eclipse of Reason (Horkheimer, 1947), Dialectic of Enlightenment (Horkheimer and Adorno, 1947), Critique of Instrumental Reason (Horkheimer, 1967), are evaluated in phenomenological hermeneutic methodology. The quantitative method is used to identify the same problems in our present social and political context and the integral methodology is used for the complete evaluation of this research.

Max Horkheimer’s distinction between traditional and critical theory is in one sense, merely repetition of Karl Marx’s dictum that philosophers have always interpreted the world and the point is to change it. The Institute of Social Research and the Frankfurt school, in its critique of ideology, have criticized some issues of the philosophical currents especially positivism, phenomenology, and Existentialism with an implied critique of contemporary Marxism which had turned dialectics into an alternative science or an ideological dogma. Owing to its interdisciplinary character, critical theory has been enormously influential and controversial in its claims. This study will employ the emancipatory and interpretatory function of critical theory against its predominant forms of expression. Critical theory is not a system, or reducible to any systems of prescription, but seeks to reinvigorate the interdisciplinary character in social research. This model can be introduced to our social research with the critical perspectives to overcome the negative influences of certain philosophical ideologies and to solve social and political problems.

Critical theory was originally conceived by Max Horkheimer as a materialist enterprise but his version of materialism did not reject the issues of critique inherited from idealism and the commitment to the enlightenment heritage


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became evident in Horkheimer’s famous claim that critical theory inherently involves the attempt to actualize the materialist content of idealist philosophy. Critical theory in this sense continues the theoretical innovations undertaken by George Lukacs and Karl Korsch in the early twenties. Both thinkers had also promoted a dialectical critique of crude materialism of orthodox Marxism and Positivism as well as fixed and finished philosophical systems. Horkheimer’s critical materialism anticipates what has now become known as post metaphysical thinking. The use of ‘critical theory’ as code word become evident in his early writings enabled a certain interpretation of Marxism to enter academic discourse. His Italicise and Critical Theory focuses on the distinction of traditional and critical theory. The Dialectic of Enlightenment is clearly a critique of enlightenment undertaken from the standpoint of enlightenment itself and it remains a landmark in radical thought. Horkheimer expressed that he could philosophically maintain his commitment to emancipation only by turning away from the given historical reality.

This study also identified in our country, the problems and the influences of orthodox Marxism and Positivism in the fields of education, research, social sciences, social and political cultures undermine the genuine progress of our society in its practical fields. The social sciences and social research should have critical approach with new rational revolutionary focus in order to have progressive change in the society and in the field of political culture.

References Horkheimer, M. (1937) Traditional and

Critical Theory: Selected Essays, Seabury, New York 1972

Horkheimer, M. and Ardorno, T. (1947) Dialectic of Enlightenment, Verso, London, 1979.

Horkheimer, M. (1947) Eclipse of Reason, New, Seabury, New York, 1974.

Horkheimer, M. (1967) Critique of Instrumental Reason, Seabury, New York, 1974.


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Children’s Posttraumatic Emotional Distress and Coping After a Natural Disaster: The 2004 Tsunami

G.R.K. Dissanayake1* and V.Ganepola²

¹Department of Philosophy and Psychology, Faculty of Arts, University of Peradeniya ²Department of Sociology, Faculty of Arts, University of Colombo

Introduction Natural disasters take a heavy toll on the mental health of those affected and significantly increase the risk of distress, psychological problems and mental disorders. Children are especially vulnerable to the effects of natural disasters as they are still developing an understanding of their social world and necessary coping mechanisms to withstand stress resulting from disasters. The effects of the 2004 tsunami on mental health of children are likely to be quite traumatic as the victims of the tsunami have experienced multiple, intense stressors that have been found to predict adverse outcomes, such as bereavement, threat to life, and displacement. These stressors can generally induce traumatic effects on children including mild to severe post-traumatic stress reactions such as depression, anxiety and post-traumatic stress disorder (PTSD) in response to such disasters. Among the many child psychosocial implications that have emerged in the wake of the tsunami, eating and sleep disorders and fear of the sea have been the most pervasive, and survivor guilt also remains problematic (Carballo et al., 2006).

However, children’s use of coping strategies may affect the severity and duration of their posttraumatic distress as well as the extent of impairment to their social and academic functioning. Indeed, in the absence of effective coping, the meaning and impact of traumatic events may continue to play a role in the personality and psychological development of the child. The purpose of the present study was to examine the magnitude of long-term persistent posttraumatic emotional distress and coping efforts mobilized to deal with it among children affected by the tsunami.

Methodology Participants were 126 (63 girls and 63 boys) 9 to 12 year old school children selected following the multi-stage sampling procedure from four schools affected by the tsunami in the Galle district. The participants were

Sinhalese and from families at the lower socio-economic level.

The Emotional Distress Questionnaire (EDQ), a 24-item self-report measure was designed for this study to assess the nature and magnitude of emotional distress. The Child Coping Questionnaire (CCQ), a 25-item self-report measure was developed for this study to assess the frequency of the use of different coping strategies and the relative effectiveness of each strategy in dealing with disaster related emotional distress. All the measures used in the study were validated to meet the local cultural requirements.

Approximately 15 months after the tsunami of December, 2004, after obtaining informed parental consent and child consent as well, the researcher administered a series of self-report questionnaires to 126 child participants during school hours. All self-report measures were read to the students. The battery of measures was completed in approximately 40-45 minutes.

Results The negative impact of the tsunami on the majority of children was moderate. Possible score range being 17 to 85, children's mean scores reflected moderate levels of emotional distress (M=47.37, SD=11.63). 7% of the sample reported experiencing lower levels of emotional distress, 50% reported experiencing moderate level of emotional distress while 43% of the sample reported experiencing higher level of emotional distress. However, no children reported experiencing a very high level of emotional distress. Female gender was significantly correlated with emotional distress while no significant correlation coefficients were found between age and emotional distress.

Participating children reported using religious strategy (83%) most frequently, followed by distraction (82%), and social support (81%) coping strategies. The least frequently used coping strategies were social withdrawal (20%)


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and blaming others (21%) followed by ventilation of emotions (31%). Increases in emotional distress were associated with significant increases in children's coping scores (r(126) = .42, p < .001). The level of emotional distress varied significantly among children depending upon the type of coping strategy they used (t(124) = 20.85, p < .05). Blaming others, acceptance, mental disengagement and humour were the coping strategies that were least associated with emotional distress. Regression analyses found that use of individual coping strategies explained 34% of the variance in emotional distress. Distraction (I try to forget it) made a significant contribution of beta = .21(p < .05), while cognitive restructuring ((β =.23, p < .05) and avoidance (β = .18, p < .05) also made a significant contribution indicating that increases in the use of these three coping strategies were associated with increases in the level of emotional distress. There was no significant relationship between age and gender with coping efforts.

Discussion Being affected by the loss of their familiar environment, disruption of the sense of protection and well-being, lack of care received from the care givers might have led to elevated levels of emotional distress among most of the affected children. The explanation behind the strong relationship between coping efforts and emotional distress seems to lie in the fact that the children who are highly distressed have put more effort in coping than the children experiencing a lesser amount of distress. These

results also suggest that high levels of distress following a disaster which causes multiple disruptions in the child's life, may initially elicit a variety of coping strategies, both positive and negative. These findings also indicate that the children are not passive victims of adversity, but active survivors.

Conclusions There is a small minority of children who continue to suffer from long lasting traumatic stress reactions; hence are at risk of developing psychological problems. As all children are not equally effective in choosing the coping strategies which would effectively deal with distress, some would need guidance in selecting the appropriate strategies. Findings of the current study would provide important information to the service providers, hence could be used for the benefit of the tsunami affected children.

Acknowledgements This research was made possible by a 2005 Dissertation Research Award from the National Centre for Advanced Studies (NCAS), Colombo.

References Carballo, M., Heal, B. and Horbaty, G. (2006)

Impact of the Tsunami on Psychosocial Health and Well-being, International Review of Psychiatry, 18 (3), 217-223.


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Philosophical and Systematic Analysis of Diotima's Definition of Love and Its Relation to Plato's Theory of Forms in the Symposium

A. Samaratunge

Department of Classical Languages, Faculty of Arts, University of Peradeniya Introduction The Symposium belongs to the middle dialogues of Plato. It is perhaps the most artistic composition and purports to report the encomium of love made by several speakers at a party given by Agathon to celebrate his victory at the drama festival of the year 416 BC. Though the author of this philosophical discussion, which climaxes with the metaphysical conception, is Plato, the dialogue is attributed to Socrates, possibly historical Socrates. Each speaker makes a contribution to the nature of love, while Socrates brings the threads together in his own speech, though all the while he modestly claims that all that he says he learnt from the prophetess Diotima of Mantinea, of whom we know nothing beyond what he says of her.

From the different speakers, with their generic, genealogical, cosmic, romanticized paeans and other diverse approaches contributing to the nature of the god of Love (sometimes goddess of Love) eulogize the multifaceted nature of the mysterious experience and their individual attempt to conceptualize it. Thus the dialogue is a concoction of comprehensive philosophical entity with an artistic touch. The most important among all comes from Diotima’s definition of Love, embracing a broader outlook of moral psychology and the metaphysical doctrine of Plato’s much used theory of forms directing towards unchanging, uniform, universal character to obtain the ultimate objective ground for knowledge using the vision of forms.

The other affiliated concepts that combine to build the totality of the nature of Love are definitions of beauty, desire, and good virtue that share with the Greek terminology of episteme (επίστεμε) against doxa (δοζα), the concepts dealt in the other Platonic dialogues that I hope to discuss comprehensively in the paper taking in to account the issue raised by Friedlander who claims that Platonic articulation of the vision of forms is transcendental and nothing to do with this corporeal world. Yet the concepts of the Platonic corpus have become the centre for

numerous western scholars to propound the theory of knowledge.

The objective of this paper is basically an examination of the definition of love through Diotima’s speech to examine the nature of the ladder of love in its broader perspective. Further, it examines the relationship of the theory of forms in Platonic philosophy to love.

Materials and methodology Since this brief review is entirely based on library research, primary texts and materials and some texts in their original language i.e. Greek, are used. Most of the dialogues of Plato are referred to in this study.

Results In order to fathom the complexities of the Platonic reality of forms with its philosophical attributes, the application of a Theory of Love proper is essential which is one main component used in the effort of unfolding the philosophical definition of forms accompanied with some important Socratic conceptualizations, such as Socratic virtues, definition of good, happiness, knowledge, desire which are sure ingredients of forming the whole-natured image of forms in which erotic love has the least role to play in this whole quest of intellectual vision of the highest reality.

Discussion Plato's definition of Love is not entirely an isolated attempt. It is one of the core issues of Platonic epistemology.

Among the chosen dialogues of Plato, the theory of Eros (Love), desire of what is beautiful (καλον), what is beautiful is closely akin to what is good (αγαθον) are prefigured in Plato's Lysis. In The Republic and Phaedo appear an inconclusive treatment of the doctrines of virtue, knowledge, education and happiness building up in this context to construct the ladder of love, fundamentally identical with the universal desire for good, of which a further developed and transformed


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version of discussion had already appeared in Gorgias and Meno.

At the juncture of formulating appropriate instruments for the account of Platonic Love, Plato introduces different notions of erotic reciprocity, for example ‘beloved seeing his own reflection on the lover’s eyes’ Phaedrus: 255 c-d.

As a whole, in this paper I attempt to incorporate all the constructive formulations of the Platonic conceptualization with a view to achieving the final composite picture of the conclusive philosophical doctrine of Love to view the whole-natured image of Platonic form.


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Euripides’ Alkestis “A Drama of a Devoted Wife?” Translation from the Original Greek into Sinhala with an Introduction and

Commentary

C.S.M. Wickramasinghe

Department of Classical Languages, Faculty of Arts, University of Peradeniya Euripides, as is known, was one of the greatest of Athenian dramatists and produced tragedies for the dramatic festivals held in honour of the god Dionysos. He lived from 485-406BC. He has composed about 92 plays, of which only 19 survive. He has competed 20 times in dramatic festivals and won the first place i in five. Unlike Aeschylos (?525/4-456/5BC) and Sophokles (496/5- 406BC), Euripides was regarded as a revolutionary dramatist at least by some of his contemporaries and the attacks he received from Aristophanes in his comedies provide evidence for such information. Alkestis was the last or the satyr play in a collection of three tragedies, namely, Kressae, Alkmaeon of Psophis and Telephos which he staged in 439BC and won the second place. Being a satyr play, Alkestis is not completely a tragedy but a tragedy with a happy ending. Moreover, Euripides has very tactfully injected his play with new concepts such as that the dead cannot be brought back to life. He also ridicules Olympian religion through this play.

Since a Sinhala translation of this drama of Euripides is not yet available I have taken up the onerous task of translating it in order to cover the demand from students studying Greek drama in the Sinhala medium. The importance of translating it from the original Greek is to make the translation much closer to the original Greek text. When translating a text from English to Sinhala there is a risk of distorting or misunderstanding the original Greek concepts and ideas and eventually this may not benefit the targeted audience. When such a translation is preceded and followed by an introduction and a commentary written after thorough research it will naturally benefit the specialist as well as the general reader. Moreover, this may stimulate further research in the field of Greek literature and history.

In this paper I explore one aspect I have mentioned briefly in the commentary of my translation which is whether Alkestis sacrificed herself on behalf of Admetos because she loved him or because she considered it her duty.

The present study mainly depends on library research, where a number of editions of Alkestis published in original Greek and research articles written on the subject were extensively used.

In order to make this paper comprehensible to the non-Classics audience, I perceive that a brief summary of the drama is essential:

Admetos the king of Pherai is doomed to face an early death. But the god Apollo, who was serving him as a slave at the time, tricked the Fates to agree to spare the life of Admetos if one of his family members agreed to die in his place. His family consisted of his parents, two very young children and his wife. When the time came, his parents refused to die in his stead. But his wife, Alkestis, died for him and freed his life. When she was already laid out in death, a friend, Heracles, visited Admetos. Admetos persuaded him to enter the house and be his guest on the pretext that the funeral in the house was of a non-family member and entertained him. Herakles somehow learnt the truth from a servant and determined to help his noble friend by saving his wife from Death, who was due to come and fetch her. Finally Herakles comes with Alkestis and claims to have fought with Death to save her and hands her over to Admetos.

The speech of the female servant who reported the behaviour of Alkestis in preparing for her death, the conversation between Alkestis and Admetos and the behaviour of the household are crucial items to observe in discussing what is proposed. The servant’s report gives no indication that Alkestis sacrificed herself out of love for Admetos nor that she considers it her duty to die for the husband, but it indicates her great concern and love for her children. Neither does the conversation between Alkestis and Admetos indicate her action to be motivated by love for or duty to, her husband. On the other hand, this again proves her concern for her


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offspring. Nonetheless, the contrast in the behaviour of Alkestis in these two scenes shows us that she is psychologically disturbed. Moreover, the behaviour of the rest of the household does not show that her death was expected and even Pheres seems to consider her death as a noble voluntary sacrifice but he thinks it was offered on behalf of himself and his son. Though space does not permit me to

state my argument here it will be spelt out in my paper.

In conclusion, what is clear is that her motherly love predominates over her other concerns and this anxiety has persuaded her to offer her life on behalf of Admetos.

This paper is an outcome of the research project I have undertaken with the help of a Research Grant awarded by the University of Peradeniya, to translate the tragic-comedy Alkestis of Euripides into Sinhala from the original Greek.


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Issues in Translating 'Sexuality' into Sinhala: Inadequacy of the Terms Used in the Sinhala Translation of Lady Chatterley's Lover By D.H. Lawrence

D.M. Kumarasinghe

Department of Sinhala, Faculty of Arts, University of Peradeniya The depiction of sexual and gender matters has been a controversial subject in Sinhala literature as in many other South Asian literatures. Classical Sinhalese literature consists of translations of Buddhist texts from Pali. The writers being mainly monks who emphasized the ideology of celibacy spurned sex and married life and described pleasures of life as low, rude, worldly, ignoble and leading to ruination. This attitude that was primarily intended for the monastic community gained ground among the laity. On the other hand, the impact of Hindu and Sanskrit tradition that had kāmə (love) as one of the four ideals of life was elevated to a divine form as erotic sentiment, far above worldly, natural sex. Though some Sinhala writers tried to emulate the Sanskritic models, the general attitude was discouragement of sex or love as a literary experience. However, since the 19th century secular literature became established, apparently under the influence of western literature, fiction being a newly introduced genre.

Except for a few early poetical works with descriptions of erotic scenes, and some erotic poetical works of the 17th & 18th centuries A.D., we can not find many fictional works of recent times that treat erotic themes.

Sex is without a doubt, one of the most intimate indicators of identity as it conjures up images of sexual activity, eroticism, pleasure, taboo, fantasies and desires. Language is considered to be the most intimate medium of expressing sentiments of sex. It is apparent that the Sinhala language does not have sufficient vocabulary on sexuality and gender. However, there is a hidden or vague vocabulary among Sinhala speakers for referring to sexual organs and related physical acts. Especially as a language with diaglossia, Sinhala has a standard pattern in writing. Although many taboo words are used in colloquial Sinhala such words are not used in the standard written language.

Lady Chatterley's Lover by D. H. Lawrence is one of the most famous erotic novels written in

English and further, it is believed to be a philosophic exploration of sex and sexuality. It also offers provocative perspectives: female fantasy about male sexuality for the so-called predominantly male audience. The citation below shows the philosophical background of Lady Chatterley's Lover:

"I always labor at the same thing, to make the sex relation valid and precious, instead of shameful. And this novel is the furthest I've gone. To me it is beautiful and tender and frail as the naked self is, and I shrink very much even from having it typed. Probably the typist would want to interfere-."1

"The mind has to catch up, in sex. . . . Balance up the consciousness of the act, and the act itself. Get the two in harmony. It means having a proper reverence for sex, and a proper awe of the body's strange experience. It means being able to use the so-called obscene words, because these are a natural part of the mind's consciousness of the body."2

Although the novel Lady Chatterley's Lover became very popular around the 1950s in Sri Lanka, due to the issues of gender and sexual matters that the novel covers and its alleged pornographic nature, no attempt was made to translate it into Sinhala until 1985. On the other hand, contemporary attitudes of expressing sex matters in literature was very controversial in the 1960s and 1970s; that is, “Sabhyə-asabhyə vādəyə” (the argument of courteousness and discourteousness) was one of the main arguments raised regarding this matter. However, the first translation (Wijesekara, M.)

1 'Letters, ed. Harry T.Moore (London, 1962), p. 972. The first typist did interfere; Nelly Morrison refused to go on after five chapters, and Lawrence had to farm it out to his friends. 2 "Edmund Wilson, "Signs of Life: Lady Chatterley's Lover" [19291, in Shores of Light (New York, 1961), p. 407


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was based on conventional translational practices and the language used is close to classical norms. The other translation that appeared in 1995 (Wikramasinghe, W.) was by a translator with postmodernist persuasions.

The Sinhala translators of Lady Chatterley's Lover in rendering words on sex, in general, have used clinical terms and Sanskrit words such as: yōniyə śişņəyə, garbhāşəyə, pratikūtəprāptiyə, mlēccəprətikāntiyə, anurāgī tīkşņə atyānandəyə, śukləmōcənəyə sansargakşəyə, sansarga sankatāvə, garbhə kukşiyə, utkruşţvə tīvrəvīmə, payōdhərə cucukə cumbənəyə. Sometimes they use loan words or derived forms, slang words, eg. Tattam kuttəmə, pirimi œngə, œnīmə, Sinhalisation of English terms, literally translated words: thing- ekə" male thing-pirimi œngə, endearments and euphemism, and paraphrasing: eg; rati krīdāvə nimāvē uccətəmə avastāvə. They adopted this method, as they could not find appropriate words in Sinhala to convey the exact meaning of the original. It is noteworthy that the translators have second thoughts in using the prevailing language, which is generalized, and the norms related to translation have also affected their work. Some of these operational norms were considered as barriers subsequently by critics. Here are some of the conventional norms approved by a committee3 at a time that the issues regarding translational norms were highly discussed in Sri Lanka.

"parivartanayə sndəhā tōrā ganu labanə pot ēvā parivartanəyə vənə bhāşāvə bhāvitə kərənə jənətāvəge samskrutikə ratāvə nodedərəvənə ēvā viyə yutuyə"4

"vidēśīyə sāhityə krutiyak sinhələtə parivartənəyə kərənə parivartəkəyā…………mulkrutiyen prəkāśitə jīvitə darśənəyə hō ein pilibimbu vənə sanskrutiyə hō meratətə nogœləpē nam emə potə parivratənəyə kirīmēdīdə privartəkəyā viməsilimat viyə yutuyə. Mehidī ohutə kələ hœkkē meratətə nogœləpenə krutīn œtot ēvā parivərtənəyə nokotə atharinu vinā samājayē hœngīmvələtə anukūlə vənə sē mul krutiyə sakas kirīmə novē." 5

3 Sinhala translator's conference 1965 4 Guruge, Ananda, 1965, Sinhala Pariwartana Sahitya, Department of Cultural Affairs, 58p 5 Ibid, 10p

In conclusion, these multiple perspectives place a great deal of importance on translation, as the translation of sex has become at present a socio-cultural and political act with serious theoretical and ideological implications. Sinhala is a norm governed prurient language, which does not allow its users to openly discuss the sexual matters. In order to overcome these difficulties, the Sinhala translators have utilized various devices in translating sexual matters in to Sinhala. In this study I focus on different devices used by translators and critically examine their weaknesses and adequacy while giving possible solutions.


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‘Observer’s Paradox’ in Linguistic Research

A. Velmurugu

Department of Tamil, Faculty of Arts, University of Peradeniya Introduction If a fieldworker requests an interview with a native speaker and proceeds to ask questions and record the responses, the informant will be aware that everything they say is to be observed and analysed by a linguist. Also, the informant is likely to adopt the fieldworker’s speech, make the answer more correct, use a higher register while speaking and so on. This inevitably leads to hypercorrection in the realms of phonology and vernacular. These challenges and methodological problems to collect samples of authentic casual speech faced by sociolinguists in linguistics research are referred to as ‘Observer’s Paradox’. William Labov first described this term in the late 1960s (Labov, 1972). Therefore, the methodological problem in linguistics is how to observe and record natural speech from informants, when they are not being observed.

Methodology This paper is mainly based on literary survey and personal observations. A critical analysis is done to certain research methodologies, which tries to overcome the observer’s paradox. Major works that have been done in the field of sociolinguistics throughout the past 30 years have been taken into consideration for this study.

Analysis and discussion First of all, this paper explains how dialectological data was being collected from informants by traditional dialectologists and modern dialectologists. Secondly, this paper explains how the data collection methods generate errors in data. Thirdly, this paper deals with explaining how modern researchers in western countries have set up many new ways to overcome the observer’s paradox. It examines selected research done by western scholars in the field of linguistics, and through this it focuses on how researchers themselves reveal their own way of overcoming the

observer’s paradox. Research done by Labov (1972), Trudgill (1974), Milroy (1980), Blom and Gumperz (1986), Coates (1986), Preston (1989), Johnson (1995) and Cameron (2005) were taken into account to explain how researchers have set-up new ways to overcome the observer’s paradox.

Conclusions This paper concludes that it is difficult to create a set of methods and principles to remove the ethical and philosophical constraints and to overcome the observer’s paradox. Therefore, Labov is indeed correct in referring to the problem as a paradox.

References Blom, Jan-Petter and Gumperz, J.J. (1986)

Social Meaning in Linguistic Structures: Code-Switching in Norway, In Gumperz, John, J., & Hymes, Dell (Ed), Directions in Sociolinguistics: The Ethnography of Communication, Oxford, Basil Blackwell. 407-434.

Cameron, D. (2005) Working With Spoken Discourse, London, Sage Publications, Fifth edition.

Coates, J. (1986) Women, Men and Language, London, Longman.

Johnson, S.A. (1995) Gender, Group identity and Variation in the Berlin Vernacular, Berlin, Peter Lang.

Labov, W. (1972) Sociolinguistic Patterns, Philadelphia, University of Pennsylvania Press, 61-62.

Milroy, L. (1980) Language and Social Networks, Oxford, Basil Blackwell.

Preston, D.R. (1989) Sociolinguistics and Second Language Acquisition, New York, Basil Blackwell.

Trudgill, P. (1974) The Social Differentiation of English in Norwich, Cambridge, Cambridge University Press.


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Economic Growth and Human Capital Investment in Sri Lanka

K.M.G.A. Kasturi and A.S.P. Abhayaratne*

Department of Economics and Statistics, Faculty of Arts, University of Peradeniya Introduction A salient feature in the Sri Lankan economy is its high social indices of health and education compared to other developing countries, despite its slow economic growth. A number of studies including Osmani (1993) and Bhalla and Glewwe (1986), show that these high indicators were the results of high government expenditure on welfare. Bhalakrishnan (1985), Gunathilake (2000) and Lakshman (1997) argue that Sri Lanka could have achieved the existing social development levels earlier through economic growth if the resources devoted on social welfare were invested on economic growth.

In Sri Lanka, since independence, each successive government devoted a considerable amount of government expenditure for education and health. The major aim was to achieve higher rates of economic growth through human capital development. However, after 1977, this approach has been changed to promote investment in both human capital and physical capital.

The main objective of this study is to analyze the contribution of government health and education expenditure in the case of accelerating economic growth. This study also attempts to identify the most suitable approach for economic growth. The study will be useful in making future policy decisions.

Materials and methods This study is mainly based on secondary time series data that were collected from the annual reports of the Central Bank of Sri Lanka. A multiple linear regression model is used to achieve the objectives of the study. The main variables used as independent variables were real per capita education, health and poverty-reduction expenditures. The infant mortality rate, literacy rate, life expectancy and growth rate of real per capita income were used as the dependent variables. The methodology used in Anand and Kanbur (1991) is used in the study with some changes, because Anand and Kanbur

did a study focusing on welfare expenditure and economic growth.

Limitations In this study, it was not possible to find data on the literacy rate and life expectancy for a few years. So the data for those years were calculated by using the median method.

Results The results of this study show that there is a significant impact of government expenditure on infant mortality rate, literacy rate and life expectancy. The regression results suggest that the human development may be a result of government expenditure in the sectors of education and health. However, the growth rate of real per capita income has little significant impact on human capital indicators.

Discussion It is clear that, human capital investment is a function of economic growth. So, investing for health care and education will lead to increase economic growth. On the other hand, education plays a key role in the process of economic growth to absorb modern technology. Moreover, health is a prerequisite for increasing productivity. Thus, both health and education can be seen as vital components of economic growth.

Conclusions The study concludes that investing in human development will benefit in the long run. But investing in capital accumulation will benefit even in the short run. Therefore, in the process of accelerating economic growth, investing for capital accumulation will be more productive. Investment in health and education will lead to increase human capital which leads to an increase in economic growth in the long run.

References Anand, S. and Kanbur, R. (1991) Public Policy

and Basic Needs Provision; Intervention and Achievement in Sri Lanka, The


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Political Economy of Hunger. Selected Essays, Oxford University Press. New York.

Bhalakrishnan, N. (1985) Sri Lanka As a Welfare State; An Overview, Economic Review, 11(4 & 5). 45 – 53.

Bhalla, S. and Glewwe, P. (1986) Growth and Equity in Developing Countries; A Reinterpretation of the Sri Lankan Experience, World Bank Economic Review, 1(1), 35-63.

Gunathilake, G. (2000) Development Policy Regimes, Sri Lanka’s Development Since

Independence, Nova Science Publishers, Huntington, New York, 127-152.

Lakshman, W.D. (1997) Dilemmas of Development; Fifty Years Economic Changes in Sri Lanka, Sri Lanka Association of Economists.

Osmani, S.R. (1993) Is There a Conflict Between Growth and Welfarism? The Tale of Sri Lanka, WIDER Working Papers No.109.


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Foreign Direct Investment and Economic Growth in Sri Lanka: A Causality Approach

N. Balamurali

Department of Economics and Statistics, Faculty of Arts, University of Peradeniya Introduction In recent years, policymakers in developing countries became convinced that foreign direct investment (FDI) is needed to boost economic growth. It is claimed that FDI can create employment, increase technological development in the recipient country and improve the economic condition of the country in general.

Researchers differ in their view of the contribution of FDI to economic growth. Some see FDI as a very important tool for economic growth especially in less developed countries while others claim this is not so.

The main objective of this study is to examine whether there exists a causal relationship between FDI and economic growth in Sri Lanka using the Granger causality method.

Methodology This study is based on annual data on real GDP, FDI, domestic investment (DI), labour force (LA) and openness of the trade regime covering the period from 1977 to 2006. Data were collected from the annual reports of the Central Bank of Sri Lanka. The effect of trade liberalization on economic growth channels through exports and imports to real gross domestic product (GDP). As reliable data on the capital stock is not available, the ratio of the gross fixed domestic investment to GDP is employed as a proxy variable to represent capital stock. In this study, nationally owned investments are defined as gross fixed domestic investment less net FDI inflows (DI) which is used as a proxy for capital. Openness of trade policy regime (OPENNESS) is represented by a proxy variable defined as the ratio of total merchandise trade in goods (imports + exports) to GDP. LA is the size of the labour force.

The estimation methodology consists of three stages. The first stage is to test for unit roots of the relevant time series variables by using Augmented Dicky-Fuller (1981) (ADF) test and the Phillips-Perron (Phillips and Perron, 1988) test. These tests have been performed to

examine the order of integration of variables before employing them in the regression and Granger causality test. In stage two a multiple linear regression model is used to identify factors affecting economic growth. All variables enter into the regression model in log form. In stage three is the Granger causality test is applied to measure the linear causation between FDI and economic growth.

Table 1. Results of the Augmented Dickey-Fuller- Unit Root Test with Trend

Series Level 1st difference

2nd difference

L(GDP) -3.38 -2.87 -5.68** L(FDI) -2.90 -7.014** -6.4** L(DI) -4.01* -2.79 -4.7** L(OP) -1.85 -4.38* -7.59** L(LA) -3.11 -3.32 -5.33**

Note: * denotes rejection of null hypothesis at the 5% level significance and **denotes rejections of null hypothesis at the 1% level of significance

Table 2. Regression Results

Dependent Variable: Log (GDP) VIF Constant 3.143300

(0.3786)

L(FDI) 0.025526 (0.02242)

9.8

L(DI) 1.262971* (0.07497)

9.5

L(LA) 1.224996* (0.15939)

7.6

L(OP) 0.695140* (0.11059)

5.4

R2 =0.94% DW=1.876702 F –Statistics=2633.763 Note : The numbers in the parenthesis are standard–errors.*indicates that the coefficients are significant at the 5% level.


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Table 3: The Granger causality test.

Direction Lag F-Statistic P

L(FDI) to L(GDP) 1 0.58986 0.449

L(GDP) to L(FDI) 1 10.404* 0.003

Note: * denotes rejection of null hypothesis at the 5% significance level. Empirical results show that all variables are stationary in second difference (Table 1) and suggest that the estimated coefficient for FDI does not significantly contribute to economic growth though positively related. Other variables such as DI, OPENNESS, and LA significantly influence economic growth at the 5% significance level.6

Based on the Granger causality test, the null hypothesis that FDI does not cause economic growth is not rejected at the 5% level of significance. The second null hypothesis that economic growth does not cause FDI is rejected at the 5% level of significance, which indicates there is one-way causation from economic growth to FDI.

Discussion Empirical evidence of recent studies is mixed. For e.g. Frimopong (2006) found no causality between FDI and economic growth. The results of the present study are similar to those previously found for Sri Lanka by (Athukorala and Karunarathna, 2004).7

Conclusions This study finds that FDI is not a significant determinant of economic growth but economic growth is necessary to attract FDI. Other variables such as DI, OPENNESS, and LA 6 The Durbin-Watson (DW) test for autocorrelation in the error term indicates that there is no autocorrelation (value=1.87).Variance inflation factors (VIF) of all explanatory variables are less than 10, indicating that there is no severe multicollinearity among the explanatory variables. 7 Our contribution to the literature beyond Athukorala and Karunarathne (2004) is in using a longer time period and including additional variables (e.g. labour force) in our analysis.

contribute positively to economic growth. The finding that FDI does not cause economic growth and economic growth causes FDI is puzzling and may arise due to following reasons.

Firstly, we used aggregate data which are in monetary values and these data results shows only a statistical relationship. Some impacts of FDI in Sri Lanka quantitatively such as, knowledge acquisition technology, international image can not be measured and it may take a considerable time before these variables affect economic growth. Secondly, the extent of FDI inflows to Sri Lanka is relatively small and that may have contributed to the lack of significance impact on economic growth. Thirdly, there may be other factors that influence the relationship between FDI and economic growth, for example, firm level production and the value addition of firm to domestic value addition. Other possible reasons include the small sample size, the use of net FDI instead of gross FDI and the possibility of cointegration.

Future research in this area may be able to remedy these limitations and also analyze the causal link in a multivariate VAR system to take account of other vital determinants of FDI and economic growth.

References Athukorala, P.P.A.W and Karunaratna, R.M.

(2004) The Impact of Foreign Direct Investments on Economic Growth in Sri Lanka, Sri Lankan Economic Journal, 5, 88-119.

Phillips, P.C.B. and Perron, P. (1988) Testing for Unit Root in Time Series Regression. Biometrica 75, 335-346.


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The Causes of Domestic Violence and Its Impact on Rural Women Victims

J.A.P.S. Perera

Department of Sociology, Faculty of Arts, University of Peradeniya Introduction Domestic violence is physical or psychological abuse of power that leaves one’s spouse, partner or other family member within the household feeling physically hurt, sad, depressed, despairing and fearful. It is just one amongst many forms of violence against women and is also recognized as the most pervasive major social issue in the world today. It brutalizes women from the cradle to grave. It also attacks and undervalues the dignity of women while leaving them vulnerable and fearful.

Existing studies have revealed the following features in relation to domestic violence against women. Domestic violence is a significant feature in rural communities where there is a higher reported incidence of domestic violence than in metropolitan settings. The overwhelming majority of victims of domestic violence in rural areas are women with most perpetrators being male. It is evident that domestic violence against women is a significant feature in rural communities. So this study attempts to find out the causes and the impact of it on rural women victims fulfilling a vacuum relating to this research area. This study will be of relevance to every individual in every level of society including women, policy makers, and local bodies involved in development processes.

Objectives of the study The purpose of this study is two fold. First, it tries to identify the causes of domestic violence against rural women. Second, it attempts to understand the impact of it on women victims.

Research methodology A total number of 16 households afflicted with domestic violence in a rural village in Mawanella Divisional Secretariat area has been considered as the research sample of this small scale, in-depth study. The method of data collection is qualitative and the information has been collected through informal interviews and the case study method. The obtained data has

been analyzed manually through the method of thematization.

Findings of the study This study reveals that 90% of the rural women encounter numerous gender based oppressions and are victimized throughout their lives in different stages.75% of the women in the age group 30-50 years are victimized by their spouses. Wife -beating is the major harassment that they encounter in addition to verbal abusing, torturing, marital rape, insult and harming their asses.

According to research findings, 50% of the victims are illiterate or less educated and belong to poor households. The particular aspects of rural life which include conservative community expectations of behavior, strict cultural ties and community pressure to preserve tradition, lack of access to safe alternative accommodations, women’s pessimistic attitudes towards womanhood, lack of understanding of individual rights, fear of deportation are the major causes of domestic violence against rural women. Poor economical status, pregnancy, disability and rigid religious beliefs are recognized as minor causes of it. The study also reveals that domestic violence occurs directly and indirectly in the forms of physical, mental or verbal abuse ranging from assaulting to rape and murder.

The findings of the study indicate that violence has a huge impact on rural women victims. It affects their mental, emotional and physical health and even results in death. It also prevents or restricts women’s participation in day to day activities, in family life, cultural activities and in the work force. Fear of violence restricts their movement and behavior, isolates them from friends and family and forces them into destitution. The abused suffer from deprivation, anxiety, psychosomatic sympathy, sexual dysfunctions and reproductive disorders.


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Conclusions and recommendations Several important insights emerged from this study. On the basis of the data analysis the researcher draws the following conclusions.

• The major causes of domestic violence against rural women are specific factors related to rural living

• Violence is high among the women from less educated, unemployed or underemployed households

• That women are victimized mainly by males while a few women are victimized by both women and men is an important revelation of the study.

This study brings some comprehensive recommendations for addressing and responding to this problem. This can be done through prevention, treatment and support. Prevention has long term aspects and support and treatment can be either short term or long term. These measures include:

1. Supporting abused women materially and spiritually through anger management trainings, awareness programmes and adequate religious guidance

2. Providing medical treatment to the injured

3. Developing a policy frame work to reduce and prevent violent behavior

4. Developing a public health approach to this specific problem

5. Revising the existing laws and imposing strict laws

6. Changing the negative attitudes of women of womanhood will be an effective attempt in addressing violent related issues. This can be done by mobilizing them through building their institutional capacities.


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External Intervention and Conflict Outcome: Analyzing the Effects of Intervention Strategies in Sri Lanka

M.M. Ihjas

Department of Political Science, Faculty of Arts, University of Peradeniya Introduction Recent empirical research on the topic of the role of outside state intervention in civil war duration has tended to suggest an overwhelming common and consistent pattern of argumentation that interventions in general tend to prolong the expected duration of civil conflicts, regardless of the form and strategy adopted by the intervener. In the mean time, management of internal conflicts has become increasingly important since the end of the cold war (Regan, 2000) particularly through the involvement of individual states and multilateral institutions such as the United Nations and other regional organizations. In Sri Lanka, the civil war between the Tamil Tigers and the government has experienced a series of outside interventions aimed at its management from its onset in the early 1980s. Past academic studies on the issue, however, tend to suggest a mix of outcomes that resulted from such interventions which constitute either shortening or lengthening the duration of the civil war depending on the assessment criterion developed by the general empirical studies (Regan, 2000). For instance, the major goal of intervention is the cessation of hostilities, regardless of the factors that motivated the intervention (Regan, 2000). Similarly, if there was a cessation of hostilities between the combatants for a period of more than six months after an intervention occurred it is coded as successful in shortening the expected duration of the conflict (Regan, 2000).

This contrasting picture captured by these two literatures leads to some important questions to be raised and answered over the existence of difference between the two literatures. Firstly, how does intervention actually affect the conflict in Sri Lanka? Secondly, what kind of relationship does exist between intervention strategies and the course of the conflict in Sri Lanka?

Methodology To facilitate the data analysis, an integrated descriptive analytical framework consisting qualitative methods related to process analysis

and major patterns of empirical arguments are utilized to examine the relationships between the various independent and other variables, and the changes in the course and the level of violence of the conflict. To carry out this the data utilized for the analysis are treated at two levels. The first one focuses on the features associated with the conflict, and includes variables such as the nature and dynamics of the conflict, the number of interveners involved, whether the interventions are in support of a group or on behalf of both sides, if there was any involvement by other actors, and changes in the group’s rebellion level, among other factors. The second level treats the various aspects of each intervention attempt and includes variables such as the type of state intervener, the forms of assistance furnished, the intensity of the aid, the recipients and the length of the interventions.

Results Results derived from this analysis show dichotomous findings that that intervention strategy and course of the conflict are positively correlated, and the extent of this correlation is conditioned to the function of the subjective factors, which, while supporting the empirical argument that interventions in general, and strategies in particular, influence the expected duration of a civil war, casts skepticism and criticism on the conclusion that intervention leads to longer civil war. This skepticism lies primarily with the inadequate nature of the empirical models to address the role and effect of some subjective factors on the intervention outcome.

Discussion Intervention in general prolongs the expected duration of the conflict in Sri Lanka regardless of form, strategy and sequence of execution, although Norway-led multilateral intervention made a difference on this general understanding in its early years. This finding supports the understanding and argumentation upheld by the general empirical scholarship. Further, it is evident that there exists a positive correlation between intervention strategies and


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the conflict outcome in the Sri Lankan context. This in some sense stands contrary to the general argumentation of the empirical literature that intervention in general tends to prolong the expected duration of conflict regardless of form, strategy and sequence of execution. This divergence of effect can be attributed to the possible existence of some theoretical and methodological defects in the treatment of the role and effect of other unobservable factors in analyzing factorial role and effects on intervention outcome, and thus it could be that the existing theoretical and methodological design suffer from inadequacy in capturing a comprehensive and more plausible picture of the phenomenon. However, it can also be argued that certain strategic (tactical) and contextual (conflict) factors tend to make a difference in the overall effect of intervention in Sri Lankan context. This on the other hand provides a new insight and emphasis of aspects that had been either overlooked or downplayed by past studies on the issue.

Conclusions There exists a strong correlation between intervention strategy, as an exercise of conflict management and the instrument of achieving it, and the course of a conflict. This correlation, however, is seriously affected by strategic and contextual factors at least in the Sri Lankan context, where political and strategic uncertainty between the protagonists turned the exercise of differing intervention strategies by different interveners at different times into a deadlocked and protracted peace process. Thus, it can be concluded that interventions in general tend to increase the expected duration of the conflict in Sri Lanka, although the Norway led multilateral intervention differed slightly from this overall outcome.

References Regan, P.M. (2000) Civil War and Foreign

Powers: Outside Intervention in Intrastate Conflict, Ann Arbor, The University of Michigan Press.


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Classroom Realities

S.K. Embakke

Department of Education, Faculty of Arts, University of Peradeniya Introduction Education may be considered as a human right which aims to create a splendid society. Since human beings are entitled to equal rights every person should have access to equal education.

In order to achieve this goal a teacher is expected to play a key role. It is the teacher’s prime responsibility to identify students’ talents and abilities and to develop these accordingly. However, a realistic consideration of the atmosphere that prevails in a classroom reveals that students have become victims of teacher typification. This sad situation has become more or less a general feature of most of the classrooms in the Sri Lankan school system. The inevitable consequence of this is a distinctly unhealthy classroom environment. Consequently, the students may develop a tendency to ignore teacher activities in general. This will evidently be an obstacle which will prevent the students from enjoying the benefits of education.

This research study, therefore, makes an attempt to identify how teachers use their authority to typify students during the teaching and learning process. The study was conducted within a social science framework

Research methodology Using Becker’s typification theoretical model, ethnographic research methods were adopted for the collection of data. Data collected from participant observation, interviews and discourse analysis, facilitated the triangulation of data while at the same time increasing the reliability of the collected data. The research site was a national school, and the research sample comprised of 12 teachers and 136 students. The focus of the research study was to find out the extent of typification and how it affects the academic progress and behaviour of the students.

Findings Teachers typified their students by using three determinants. They are learning, discipline and morality. The study revealed that 75% of the teachers typify the majority of the students as

“good learners” while the other 25% of the teachers hold the opposite view. Furthermore, the criterion used in typifying students as “good” or “bad” learners differed from teacher to teacher.

In the field of discipline teachers categorized the students as “having conformed behavior”, “not having conformed behavior”, and exhibiting dual characteristics (intermediary). The study revealed that the majority of the students were “having conformed behavior”. The gender based analysis indicated that a high proportion of girls resorted to conformed behavior while a majority of boys violated the disciplinary rules. Almost all the teachers in the sample considered obeying the teacher’s orders, completion of assignment work on time, and punctuality as main characteristics of discipline. Meanwhile noisy and irritating behavior inside the classroom was considered as one of the non- conforming behaviour. The students who fell into the intermediary characteristics were those who were “not difficult to handle”.

Teachers categorized students as “followers” and “distracters” based on morality. This categorization was done based on several moral factors which they identified. These were cleanliness, non aggression, ambition and work, relationship between the peer groups, respect for elders, and moderate behavior.

Discussion The teacher perceptions of students were not based on any distinct factors. This revealed that the teachers lacked the professionalism expected from them. Though teachers are expected to be focused on the full development of the students, the teachers in the sample were concerned only about a few of the factors that affected the teaching- learning situation in the classroom.

Even though teachers are expected to be very concerned about students’ disciplinary issues, the teachers in the chosen sample have only focused on the factors affecting the student’s behavior during lesson presentation.


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Conclusions Although the teacher’s primary role is to facilitate the students’ learning to reach their full potential, it is also an unwritten concern

that teachers should be concerned about their discipline and moral development. However, the data in the study revealed that only a small percentage of teachers did so.


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A Study on Gender Differences in Food Habits and Sport Performance among Secondary School Boys and Girls in Sri Lanka

W. Senevirathne and P. Sethunge*

Department of Education, Faculty of Arts, University of Peradeniya Introduction Sri Lankan Sport Bodies are searching for new strategies to improve performances of men and women in sports competitions. It is also found that there has been considerable progress in sport performances in secondary schools in recent years.

According to the Department of Nutrition of the Australian Institute of Sports (AIS), a sport activity can be divided into three main periods (phases) namely the pre-exercise period, period during exercise, and post–exercise period.

This research focuses on the food habits and sport performance of teenagers in secondary schools of Sri Lanka. The main objectives of the research were to identify the salient differences in food habits of students at different periods of a sport activity and to identify gender differences in food habits and sport performance among secondary school boys and girls.

Methodology A descriptive survey method was adopted to identify the significant differences of the food habits of students. The research was limited to students who performed well in sports in secondary schools.

The method of situation sampling (non-randomized) was used to select 10 secondary schools in the Kandy District. From these 10 schools, a sample of 100 (N=100) students were selected including 50 girls and 50 boys who were sportsmen and women between the ages of 17 and19 years.

Data were obtained from a questionnaire, which was prepared according to the AIS Department of Sports Nutrition standards. (www.ais.org.au/nutrition) The questionnaires were distributed to the sample of students selected and their responses were obtained.

The descriptive method and two major statistical methods, viz: binominal probability test and Pearson’s chi-square test, were used to

analyze data. These tests were used to analyze the significance of students’ food habits at three different periods of sport activity. The analysis was used to identify gender differences in food habits, and to assess sport performances among secondary school boys and girls.

Results According to the binominal test, girls who had good food habits in the pre-exercise period showed a higher level of performance than boys of a similar category (For breakfast, lunch and dinner, carbohydrate, protein, snack, and drinks intake, and for supplementary diets P values are less than 0.05). Regarding water intake no significant difference (P > 0.05) was recorded. In the period during exercise, girls who followed good food habits (in carbohydrate and water intake) showed higher levels of performance than boys (P<0.05). However, no significant difference in performance in other drink habits (P>0.05) was observed. After the exercise, a significant difference in performance was shown by girls than boys with a protein intake and post exercise interruption. No significant difference was recorded regarding carbohydrate and water intake.

The significant difference of gender and sport performance was calculated for indoor and outdoor games among boys and girls using Pearson’s chi square test. The test shows P value = 0.839. According to the above chi square test there was no significant difference between genders with regard to performance in indoor games and outdoor games.

This study also revealed that in the pre-exercise period 95%, 70% and 100% of the participants reported having breakfast, lunch and dinner respectively. Skipping breakfast was not statistically linked to gender. Other studies have shown that consumption of breakfast has some influence on meal and snack patterns. For example, adolescents who skip breakfast consume a hot lunch less frequently than adolescents who have breakfast on a daily


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basis. (Cavadini et al., 1999; Narring and Michaud, 1995).

There is a significant difference in lunch habits among boys and girls (62% vs. 89% with P<0.05). The research found no difference in frequency of consumption of meals and snacks between girls and boys, and as expected the directory survey shows that the mean daily energy intake is lower among girls than among boys (Narring and Michaud, 1995).

Responses of students to open ended questions revealed that the food habits of students were influenced by parents, teachers, coaches, peers, cultural factors and their own psychological factors. Meanwhile research revealed that the food habits of both boys and girls were found to be quite traditional, whereby they tend to consume traditional foods.

Discussion According to the chi square test and binominal probability test the results indicate mixed results (both significant difference and no

significant difference) in food habits and sport performance among girls and boys.

Conclusions The study revealed that there is a significant difference in food habits at the pre exercise period, during the exercise period and post exercise period between girls and boys in some food habits components. The association between sport performance and food habits was significantly higher among girls than boys.

References Cavadini, C., Decarli, B., Dirran, H., Candery,

M., Narring, F. and Michaud, P.A. (1999) Assessment of adolescent food habits in Switzerland, Appetite, 32 (1), 97-106.

Narring, F. and Michaud, P.A. (1995) Methodological issues in adolescent health surveys: the case of the Swiss Multi centre-adolescent Survey on Health, Soz Praventivmed, 40(3), 172-182.


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A Study of Western Musical Techniques Used in Sinhala Light Songs During the 20th Century

M. Alawathukotuwa

Department of Fine Arts, Faculty of Arts, University of Peradeniya Introduction Music can be classified as Eastern and Western. While there are similarities between them, the two systems employ certain techniques peculiar to each one. These techniques are used not only in classical music but also in applied music such as film and drama scores and light songs. It is evident that western techniques are employed now a days in creative music whatever the fundamental music system. However, only the simplest forms appear to be used. The aim of the present research is to study from a musicological point of view the employment of musical techniques in light songs composed in Sri Lanka. These include counterpoints, harmony, local and instrumental techniques. It is also possible to observe the use of techniques employed in folk music of the west such as Yodelling and fiddle-playing.

Methodology The research methodology followed in the study is a survey of relevant musical compositions. Library research includes book collections and archives of recordings such as those at the Sri Lanka Broadcasting Cooperation. Information was sought through interviews with artistes, composers and producers who were influenced by western music. In this research I faced some difficulties in finding certain types of applied music such as recordings of music for drama, films and tele-dramas.

Discussion The use of western music techniques has introduced a variety of forms in Sinhala light songs. The traditional Stay and Antara structures have been expanded through external elements such as introduction, interlude and coda. These elements are first evident in the songs of the gramophone era but became more complex in film songs. From the 1960s so-called “group songs” employed close harmony and Spanish Guitar type accompaniments. Since the use of vocal harmony was the main feature, these groups came to be known as harmony groups.

Each use of western techniques was confined to these single forms (eg. The use of the primary chords). However with time, more complex chord changes were introduced and western techniques came to be employed to highlight the meaning or emotion of the songs and lyrics. Examples include the song Sandakada pahanaka from the film Matara Achchi sung by Sunil Edirisingha, and music composed by Victor Ratnayaka and the song named Sulan koda wehi sung by Neela Wicramasingha and composed by Sena Weeerasekara . Both these examples use counterpoint to illustrate the meaning of the lyric.

Modulation which is an important feature of western music is also employed occasionally. Eg. Viyoo Gee Geyena hade sung by Neela Wicramasingha with music by Nimal Mendis, and the song Nimterak nodutu sung by Sunil Edirisingha with music by Rohana Weerasingha . Following the practice of some western songs these have their last chorus sung in a higher key (compare the song from the late 50s We were two innocent hearts sung by Tony Brent).

Vocal music plays an important part in the western system, and the voices are systematically classified and blended; but the use of multiple layers of voice in Sri Lankan music seems to be somewhat limited. Mr. Premasiri Kemadasa’s songs often employed vocal arrangements suggestive of western music. Eg- song Kanyawi sung by Amarasiri Pieris and the Song Udumbara Hinehenawa.

Although local singers can be found whose voices fall within the ranges of western voice classification such voices are not employed methodically in Sri Lanka.

In addition to the standard techniques of western music, Sri Lankan songs also employ techniques found in western folk music such as yodeling.

The influence of western techniques is stronger in instrumental music. Eg- the positions, systems of tuning and playing techniques for


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the Violin such as Pizzicato and Vibrato are used in Sri Lankan songs.

Results Whatever the melodic basis of the song, western techniques figure prominently. These are introduced with the objective of giving

depth and ornamentation to the form of the songs.


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The Original Concept of Sound Material in Chinese Music Sheng（声) and Yin（音）

L. Seneheweera

Department of Fine Arts, Faculty of Arts, University of Peradeniya Introduction Chinese music has a rich and complex history dating back more than two millennia. It is proved with written documents, information from carvings, paintings and oracle bones and musical instruments. Writings preserved on oracle bones (i.e. used for divination) date from the Shang Dynasty (1600-1046 B.C.). Moreover, the aforesaid documents have discussed basic elements in music such as ‘sound’, sheng（声). The two terms of sheng and yin were described as sound materials in Chinese music history. Sometimes these two words refer to the same concepts and sometimes they refer to different concepts. Normally sheng and yin mean natural sound. Therefore it can be referred as one concept i. e. shengyin （声音）. Moreover, sheng and yin refer also to ‘tone’ yueyin （乐音) of music and have been referred to as having the same meaning as lü (律). The purpose of this paper is to discuss the use of these two terms in historical Chinese records.

Methodology The paper analyzes primary data based on Chinese documents written in the Chinese language, and also uses secondary data.

Results and discussion It seems the terms sheng（声）, yin （音） and lü (律) all indicate musical tone. For instance the book of Zuo Zhuan (左传）， ‘Zuo’s commentaries on history’, Zuo Zhuan (左传) (5th century B.C.) mentions wu sheng, （五声）， liu lü （六律）, qi yin（七音）.1 All of these three terms are musical sound. Sometimes these two concepts are strictly distinguished. For instance the book ‘Records of music’ yueji （乐记) (5th century B.C.) 1 In Chinese wu（五）, liu, (六), qi (七) corresponding respectively to five, six and seven.

offers the following comment: “Those who are able to realize sheng (声) but not realize birds and beasts, those who are able to realize Yin but not yue (乐) are the common people. Only intellectual gentlemen can enjoy Yue (乐 ) well”. It means those who are able to appreciate music, yue(乐), will be able to distinguish musical sound, musical tone and music very clearly. According to the above mentioned comment sheng （声) equals ‘musical sound’, yin xiang (音响). Yin （音） equals ‘musical tone’, yue yin(乐音) and yue (乐) equals music , yin yue (音乐). There is another source ‘Essay on no sadness or happiness in music’ Shen wu ai le lun （声无哀乐论 (250 A.D.）written by Ji Kang. In his book, he mentions that the relationship of sheng (声) and yin (音) is just like the relationship of body and spirit. It is pointed out that sheng (声) is the form of music and yin (音) is the content of music. However, in certain situations, if the words sheng （声) and yin (音) combine with a numeral figure the meaning becomes the ‘scale’ yinjie (音阶)。 For instance, wu sheng（五声） with wu yin (五音) means pentatonic scale, wu sheng yin jie (五声音阶). Qi sheng （七声) with qi yin (七音) it means heptatonic scale qi sheng yin jie (七声音阶). Furthermore the numerical figure has been added to yin (音) such as bayin （八音） (ba meaning eight) as one word. This word was existed in Zhou Dynasty and at that time bayin （八音） had been used to divide musical instruments according to the material used for making musical instruments. These eight groups as are follows: gold, jin ( 金), stone, shi(石), silk si (丝), (bamboo), zhu (竹) , cucurbit/gourd , pao (匏), clay, tu (土), leather, ge(革 ), wood, mu(木).

Conclusions According to the above mentioned, the sheng(声) and yin(音) sometimes overlapped. However it can be seen that these two terms are used for musical sound. These musical sounds produced pentatonic and heptatonic scale in Chinese music.


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Masculinity in Kandyan Dance

S. Mantillake

Department of Fine Arts, Faculty of Arts, University of Peradeniya Introduction Today Kandyan dance is performed by both males and females widely in Sri Lanka, even though it was originally performed only by males. Due to the social development of the country Kandyan dance was opened to females. This happened as a result of many important socio-political and economic changes in Sri Lankan society.

Although Kandyan dance is now performed widely by both males and females, the dance form itself takes a masculine form since it has been dominated by males. Kapferer (1983) and Obeyesekere (1984) have discussed the masculine condition in Theatre art of Sri Lanka, while Nürnberger (1998) has particularly examined the masculine condition of Kandyan dance.

The objective of this research is to explore the masculine characteristics of Kandyan dance. Especial attention is paid to performing art characteristics of Kandyan dance.

Methodology For this research live Kandyan dance performances were observed and visual media such as video clips and images documenting Kandyan dance performances were analyzed.

Literature on the subject matter was referred and traditional dance masters as well as prominent female exponents in the field were interviewed where necessary.

In addition the author’s personal experience of more than fifteen years in Kandyan dance provided subjective unpublished data.

Results Research data have been analyzed from a semiotic point of view and the theory of four Abhinayas (Āngika, Vācika, Sātvika and Āhārya) was used to interpret the data. According to the results, all elements examined in traditional Kandyan dance were masculine. Apart from a few exceptions, all other elements

examined in contemporary Kandyan dance were also masculine.

Discussion As mentioned earlier it was revealed that almost all elements and features examined in Kandyan dance were masculine, drawing us to decide that Kandyan dance is a masculine dance form. Sātvika abhinaya that deals with human emotions is hardly seen in Kandyan dance. But the other three Abhinayas helped to explore the masculine characteristics of Kandyan dance.

When considering Āngika abhinaya, the expression through the dancer’s body, Tāndava and Lāsya movements are significant. Kandyan dance is filled with Tāndava movements, the frenetic movements of dance especially referred in Indian classical dancing. Lāsya is described as a feminine dance form in traditional Indian performing art theories. But in Kandyan dance virtually no Lāsya movements are found. Even female dancers use Tāndava movements when they perform Kandyan dance.

Vācika abhinaya which consists of oral accompaniments is also used in Kandyan dance. In contemporary Kandyan dance, vocal components to be sung during dance events are used by both male and female dancers since character representation is ignored. But in traditional Kandyan dance there are dialogues between characters and they are composed for males to deliver, since almost all those dialogues were created from a male point of view.

The main element that can be discussed under Āhārya abhinaya in Kandyan dance is the costume. In traditional Kandyan dance all dance costumes including the costume of the drum player, have been designed for males but not for females. Some new costumes have been introduced for females in contemporary Kandyan dance. Even today females are culturally not allowed to wear many traditional dance costumes designed for males. According to traditional dance masters the dance costume


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is sacred and not to be worn by females. Treating females as impure creatures by traditional artistes is the basis of this idea. Restrictions and criticisms have been made by traditional dance masters against attempts by females to wear traditional Kandyan dance costumes.

Conclusions In this research some features of Kandyan dance have been analyzed in order to explore the masculine characteristics of Kandyan dance. It also included a discussion as to how this dance form can be determined as a

masculine dance form. Treating females as impure creatures by traditional artistes was one of the main reasons that kept females away from Kandyan dance.

References Nürnberger, M. (1998) Dance is the language

of the Gods: The Chitrasena School and traditional roots of Sri Lankan stage–dance, Amsterdam, Vrie University Press.

Obeyesekere, G. (1984) The Cult of Goddess Pattini, Chicago, University of Chicago Press.


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Identification of Mule (Equus Hemionus) as Aśvataraya in Ancient Sri Lanka by Unearthed Bones and Literature

R.M.M. Chandraratne

Department of Archaeology, Faculty of Arts, University of Peradeniya Introduction The main objective of this study is to infer the presence of the mule (Equus hemionus) in the ancient Sri Lanka. The first ever archaeological identification of mule bones in Sri Lanka was carried out by the author (Chandraratne, 2005). The ancient Sri Lankan literature cites two kinds of horses, horses (Assa/Aśva) and Sind horses (Saindhava) that are identified referring to archaeological and literary sources.

Material The sample consists of an isolated premolar of Equus from Jetavana Pilimage (JPL). Other sources of data are skeletal measurements of the modern horse, published archaeological data on the mule (Meadow and Patel, 1997) and ancient Sinhalese and Pali literature (Ummagga Jataka, 1966, Jatakapali, 1939).

Methodology New Archaeological Theory advocated ‘generalization of data’ which came to be regarded as archaeology’s supreme achievement (Redman, 1973). This methodology was used for the above literary evidence. The application of osteo-archaeological measurements which is employed for species separation, size variation and sex determination (Uermann, 1978) was used for the species separation between horse and mule. Specifically, the morphological features were compared with the osteometric data of equid teeth from the Jetavana, and Surkotada, and modern horses were used for the confirmation of this research.

Results

Figure 1

Figure 1 shows that a premolar of Equus species from the JPL is smaller in size to modern horses, but is metrically similar to that of Surkotada. The species at Surkotada are identified as mule (Equus hemionus). The JPL sample is similar to the mule hence it can be identified as the mule. Literary sources provide the words Ājānīya Aśva, Sindhava and Aśvatara (Sindhava?) to identify the mule. In the Jatakapali (1932) and the Ummagga Jataka, mule is referred to Sindhava, and it is also mentioned that Ājānīya Aśva means an excellent (true) horse, i.e. not hybrid with other species.

Discussion The hybrid species of equids may be described as a truly man-made animal. The mule’s mother is mare (Equus caballus) while it is perhaps as the father mule (Equus hemionus) that it has made its greatest contribution to human economies in a way similar to that of the donkey (Equus asinus). It is a perfect example of hybrid vigour as a beast of burden and is more sure-footed than either the ass or the horse (Clutton-Brock, 1987). Its head is similar to the ass and the rest of the body is comparable with the horse. It is identified in the Egyptian and Mesopotamian Civilizations (1400 BC) and was also recorded from the Roman period (Clutton-Brock, 1987).Previous research on the horse remains found at Gedige (69) by Deraniyagala (1972) suggested that the teeth of the ancient small horse was metrically between Mannar ponies and modern horses, and indicates two species of horses, local and Sind. The local species might have derived from the South Indian wild horse (Equus nomadicus). The more recent research on horses raises several opinions on the origin of the South Asian species. The wild form of horses did not exist in India during the Post-Pleistocene period; consequently, the horse could not be domesticated there. Rather, domesticated horses had been introduced later (Bőkőnyi, 1997). Besides, wild horses were extinct during the late Pleistocene period and had not been domesticated in India. Nevertheless, domestic horses were considered

Fig. 1 Measurements of Premolars: Pilimage Vs Modern Horse

242628303234

JPL SUR SUR Modern262830323436

LengthWidth


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as introduced species from outside (Meadow and Patel, 1997). In the light of the above research, it is difficult to accept the opinion given by Deraniyagala (1972) on South Indian wild horses. Domestic horses and hybrid species were probably introduced into India

from the Persian Gulf region and subsequently spread all over India (Bökönyi, 1997).

The author believes that local and Sind horses refer to the mule. It is known as Aśvatarya in Sinhala and Assataro in Pali (Table 1).

Table 1. Selected literary evidence for Sindhavo and Aśvatara in Sri Lanka

Literary terms Sources Chronology Sindhavo (mule?) Mahavamsa (23: 71) 5th Century AD Susetha chatura sindhavam (four white mule?)

Mahavamsa (31: 38) data is related to 2nd century BC)

Assataro (mule) Jatakapali (in Pali) 5th Century AD Astara (mule) Dampiya-Atuva-Geta-Padaya 10th Century AD Aśvataraya (mule) UmmaggaJataka 14th Century AD

The early evidence goes back to the Anuradhapura Period (900 BC-1000 AD), The Dampiya Atuva Geta Padaya (74/31) states that it was born after interbreeding of ass and mare. The Mahavamsa refers to horses that were commonly used by kings and royal officials for transportation and warfare. For instance, Sena and Guttika (177-155 BC), had brought Saindhava horses. The state chariot of King Dutugemunu (101-77 BC) was drawn by the white Sindhu horses while Velusumana tamed a wild Sindhu horse. Finally it appears that a mule (Sindhava) was more useful than a horse at that time and was common in comparison to true horses because of its adaptability to the environment.

References Bőkőnyi, S. (1997) Horse Remains from the

Prehistoric Site of Surkotada, Kuth, Late 3rd Millennium B.C., South Asian Studies 13, 297-307.

Chandraratne, R.M.M. (2005) Horse Remains from the Jetavana Pilimage Excavation Central Cultural Fund Anuradhapura, Proceedings of PURSE 2005, 10-35.

Deraniyagala, P.E.P. (1972) Faunal remains,

the citadel of Anuradhapura, in 1969, in the Gedige area, Ancient Ceylon, 2, 155-159.

Clutton-Brock, J. (1987) A Natural History Society of Domesticated Mammals, British Museum (Natural History), Cambridge University Press.

Jatakapali, (1939) Ed. Ven. Widurupola Piyatissa Mahanayaka Thera, Maligakanda, Colombo, The Tripitaka Publicaton Press.

Meadow, R.H. and Patel, A. (1997) A comment on “Horse remains from Surkotada”, South Asian Studies, 13, 307-315.

Redman, C.L. (1973) (Ed.) Research and Theory in Current Archaeology, New York, Willey.

Ummagga Jataka (14th Century AD) (1966) (ed.) Sucharita Gamlath and E.A.Wicramasinghe, Colombo, S. Godage and Brothers.

Uermann, H.P. (1978) Animal bone finds and economic archaeology: A critical study of osteo-archaeological methods, World Archaeology, 4, 307-322.


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Proceedings of the Peradeniya University Research Sessions, Sri Lanka, Vol.12, Part I, 30thNovember 2007

373

AUTHOR INDEX

A Abayasekara, C.L. 49, 55 Aberathna, H M.R.M 181 Abeygunawardane, S.K 269 Abeykoon, Y.M.C.E.K 258 Abeynayaka, A. 190 Abeyrathne, B.G.S.J. 157 Abeyruwan, H. 214 Abeysuriya, C. 111 Abhayaratne, A.S.P. 353 Adhikari, A.M.K.S.P. 304 Adikaram, N.K.B. 49 Adikari, S.B. 137 Alagan, R. 329 Alahakoon, A.M.U.S.K 224 Alahakoon, P.M.K. 31 Alawathukotuwa, M. 365 Alupotha, A.G.K.N. 288 Amarajeewa, B.M.R.C. 101 Amarasekara, A.K.C.J. 39 Amarasena, J.K.C. 120 Amarasena, N. 120 Amarasinghe, A.A.A.W.K. 153, 177 Amarasinghe, N.R. 92, 103 Amarasinghe, W.I. 122 Amarathunge, E.A.P. 111 Amaraweera, T.H.N.G. 298 Anandamoorthy, T. 109 Aoki, T. 211 Arachchi, R.N.R. 144 Arima, S. 18 Ariyarathna, S.M.W.T.P.K 199 Ariyaratna, R.A.Y.K. 103 Ariyaratne, H.B.S. 157, 170 Ariyasinghe, S. 126 Ariyawardana, A. 27 Arlis, M.G 244 Arulampalam, A. 263, 266, 269, 272 Arulkanthan, A. 164 Athauda, S.B.P. 53 Attanayake, A.M.C.P.K. 337 Azhaar, A.S. 1

B Bakmeedeniya, L.U 261 Balamurali, N. 355 Bandara, B.M.R. 82, 89, 94 Bandara, B.M.R. 294 Bandara, D.C. 35, 37 Bandara, D.G.V.L. 20 Bandara, H.M.N. 294 Bandara, K.A.P.A. 172, 174 Bandara, N.M.N.V 205 Bandara, N.W.R.V.N. 80 Bandoh, N. 116 Basnayake, B.M.R.K 246 Bassnayake, B.M.P.K.D. 148 Blakemore, W.F. 168 C Chandrajith, R. 49 Chandrajith, R. 284 Chandraratne, R.M.M. 370 Chandrasekara, A. 33 Chandrasekara, A. 120 Chin, D. 53 Choct, M. 12 Cyril, H.W. 6, 9 D Dangolla, A. 162, 172, 174 Dassanayake, B.K. 139, 146 Daundasekara, W.B. 309 De Costa, D.M. 1, 3 De Silva, D.D.N. 153, 177 De Silva, S. 42 De Silva, T.H.K.R. 309 De Silva, W.A.P.P. 98 Deepanee, J.K.A. 170 Devasurendra, R.S. 164 Dharamaratne, S.D. 148 Dharmagunawardana, H.A. 301 Dharmapala, H.L.P.S. 141, 148


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Dilrukshi, H.A.A. 6 Dineshanrathna, H.G.K. 286 Dissanayaka, D.M.A.G.B. 188 Dissanayaka, U.J. 188 Dissanayake, D.R.A. 166 Dissanayake, G.R.K. 344 Dissanayake, P.B.R 217, 219, 221 Dissanayake, S.B.A. 122 Dissanayake, U.B. 111, 113, 120 Dissanayake, U.N.B. 286 E Edirisinghe, J.P. 74, 77, 84 Edirisinghe, J.S. 172 Ekanayake, D.H. 98 Ekanayake, E.M.W.A. 89 Ekanayake, J.B 263, 266, 269, 272 Ekanayake, R.H.B 272 Ekanayake, S.P. 141 Elangasinghe, M.A 205 Embakke, S.K. 361 F Faham, M.A.A.M. 315 Fernando, G.W.A.R. 298 Fernandopulle, S.R.D. 157 Fogdell-Hann, A. 137 G Gamage, A.T.M. 174 Ganepola, V. 344 Gnananda, M. 340 Goonasekara, C.D.A. 129, 141, 148 Gunaratne, L.H.P. 22 Gunaratne, S.P. 160 Gunasena, G.G.A. 129 Gunathilake, P.G.L. 105 Gunatilake, J. 290 Gunawardana, D.C.A. 170 Gunawardana, V.K. 170 Gunawardena, D. 72 Gunawardena, D.C. 96, 103 Gunawardena, G.A. 166

Gunawardena, G.S.P. de S. 155, 160, 168 H Halpage, S. 162 Hanee, J.A.J. 35 Harischandra, H.K.P. 62 Harischandra, M.R.T.S. 186 Hemachandra, S.D.S. 24 Hennayake, H.M.S.K. 39 Hennayake, N. 325 Hennayake, S.K. 325 Herath, H.H.M.C.U. 320 Herath, H.M.K.G.G.H.B 221 Herath, I. 227 Herath, K.R.B 214 Herath, S. 133 Herath, W.H.M.A.T. 49 Hettiarachchi, C.V. 320 Hewapathirana, I.S. 177 Himali, S.M.C. 9 Hussain, F.M. 275 I Iddawela, D.R. 151 Ihjas, M.M. 359 Iji, P.A. 12 Ileperuma, C. 72 Ileperuma, S.C. 49 Illeperuma, D.C.K. 33 Indrasekara, S. 312 J Jamila, M.M. 307 Jayalal, R.G.U. 60 Jayaratna, N.B. 51 Jayasena, H.A.H. 284 Jayasena, Y.A.A. 141 Jayasinghe, M.G.C.M. 177 Jayasinghe, U.L.B. 92, 94, 96, 103, 107 Jayasooriya, A.P. 160, 164 Jayasooriya, P.R. 116 Jayatilake, J.A.M.S. 124 Jayaweera, D.S. 107


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Jeyaraman, U. 329 Jiffry, N. 133 Jin, L.J. 124 K Kadawathaarachchi, L. 72 Kahanda, I.M.K 233 Kalpage, C.S 193, 196, 199 Kalyanaratne, K.A.K. 120 Kanankearachchi, P.K.A.P. 141 Kaneshalingam, T. 315 Kanewela, U.G 233 Karunananda, P.A.K 219 Karunaratne, D.G.G.P 202, 208 Karunaratne, D.N. 318, 322 Karunaratne, D.N. 51, 57 Karunaratne, K.I. 139, 146 Karunaratne, S. 307 Karunaratne, S.H.P.P. 62, 98 Karunaratne, V. 57, 60, 312 Karunaratne, W.M.K.K. 74 Karunathilake, A.A.K. 89 Kasturi, K.M.G.A. 353 Kodithuwakku, K.A.S.S. 24 Kottegoda, N. 312 Kudagama, N. 160 Kularathne, M.N. 153, 177 Kumar, N.S. 51, 82, 89, 292 Kumar, V. 101 Kumara, K.B.J. 162 Kumara, W.R.B. 177 Kumarasinghe, D.M. 350 Kumarasiri, P.V.R. 141 Kumbukgolla, W.W 82, 89 L Laheetharan, A. 281 Lalantha, N. 6 Lamawansa, M.D. 135, 144 Liyanage, G.L.A.D. 318 Liyanage, L.G.A 221

M Mahatantila, K. 284 Mallawarachchi, A.S.P. 139 Malmuthuge, N.S.P. 9 Manangoda, M.G.B.S 221 Manchanayake, G.S.M. 141 Mantillake, S. 368 Mapa, R.B. 337 Menike, A.M.W 196 Mikkelsen, L.L. 12 Mubarak, M.N.A. 301 Mudalige, A.P. 101 Mudalige, S.P. 141, 148 Mudiyanse, R. 133 Munasinghe, D.M.S. 170 Munasinghe, M.D. 157 Munasinghe, S.R. 77 N Nanayakkara, D. 133 Nanayakkara, D.P. 105 Nanayakkara, D.P. 131 Nanayakkara, D.P. 162 Nanayakkara, S.D.I. 146 Nandadeva, D. 146 Nandasiri, W.T.D 181 Nasir, H.M. 278, 312 Navaratne, A.N. 72 Navaratne, D.N 266 Nawfhal, A.S.M. 334 Nawodinee, M.H.V. 84 Nazriya, N.F. 1 Nianthi, K.W.G.R. 332 Nilam, J. 133 Nishshanka, S.P. 327 Nissanka, S.P. 33 P Pallegama, R.W. 118, 126 Palugaswawa, P.S 205 Panagoda, G.J. 55 Paranavitana, G.N. 190 Pathberiya, L.G. 60


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Pathirana, C.K 214 Pathirana, G. 151 Pathirana, K.P.P 179, 181, 183 Perera, A. P. 135 Perera, A.A.I. 288 Perera, A.D.L.C. 318, 322 Perera, H.A.E.D. 126 Perera, J.A.P.S. 357 Perera, K 255 Perera, K. 133 Perera, M.H. 47 Perera, N.A.N.D. 170 Perera, P.C 241, 246, 252 Pitawala, A. 290, 298, 301 Poxton, I.R. 166 Prasanna, K.I.R 269 Premaratne, C. 329 Priyangika, S.K.N. 157 Priyantha, N. 296 Punyasiri, P.A.N. 292 Pushpakumara, D.K.N.G. 15 Puvanendran, S. 57 R Radhakrishnan, S 230 Ragel, R.G 227, 230 Rajakaruna, R.S. 62, 80, 86 Rajapakse, R.M.G. 294 Rajapakse, R.P.V.J 80, 86 Rajapakse, R.P.V.J. 170 Rajapakse, S 193 Rajapakse, S. 53 Rajapaksha, L 258 Rajapura, S.G. 49 Rajarathne, A.A.J. 174 Rajaratnam, M. 342 Rajaratne, A.A.J. 139, 146 Rajaratne, S.A. 111 Ranasinghe, H.S. 177 Ranasinghe, J.G.S. 105 Ranasinghe, J.G.S. 162 Ranasinghe, P.C 179, 183 Ranasinghe, S. 131 Ranawana, K.B. 67 Rangama, B.N.L.D. 55

Rathnayake, U. 186 Rathnayake, U.R. 179, 183 Ratnatunga, K.C. 139, 146 Ratnayake, R.M.P. 105 Ratnayake, R.M.P. 131 Rodrigo, S.K. 94 Rodrigo, U.K.S. 33 Ruwanpura, S.M.P.M. 120 S Sachindra D.A. 188 Samaranayake, B.G.L.T 224, 238, 249 Samaranayake, L.P. 124 Samarasinghe, B. 160 Samarathunga, I.R 202, 208 Samaratung, A. 346 Samaraweera, P. 70 Sandamalika, S.N.K 181 Saumyasiri, M.M.K.G. 70 Senanayake, A.M.P. 336 Senavirathne, M. 42 Seneheweera, L. 367 Senevirathne, W. 363 Seneviratne, C. 296 Seneviratne, S. 337 Sethunge, P. 363 Shanthini, R 196, 199, 255 Shyamalee, M. M.G.V 214 Silva, I. 139 Silva, I.D. 172, 175, 177 Sirisena, A.D. 49 Siriwardane, S.A.S.C 217 Sivakanesan, R. 9, 131 Sivakumar, V. 275 Sivayoganathan, C. 44 Solanki, K. 133 Sotheeswaran, S 193 Subramanium, R. 170 Sumangali, K. 86 Suraweera, A.K. 111, 116 Suriyagoda, L.D.B. 18 Susantha, K.A.S 211 Suzuki, A. 18 Svensson, M. 137


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T Tennakone, K. 275 Tennakoon, D.T.B. 294 Thevanesam, V. 82, 89 Thiruchelvam, S. 20 Tirimanne, D.N. 27 U Udugala-Ganehenege, M.Y. 304 Ukuwela, K.D.B. 67 V Velmurugu, A. 352 Vidanapathirana, E. 327 Vidanarachchi, J.K. 6, 9, 12 W Waasim, M.S.M. 278 Wagalawatte, T. 339 Wanigasekara, A. 164 Wanniarachchi, C.R. 148 Warusawithana, L. 65 Weerahewa, J. 29 Weerakoon, S.B. 186, 188 Weeraratne, T.C. 98 Weerasekara, A.I 263 Weerasinghe, W.P.T.T. 175 Weerasundera, N.K. 160 Welagedara, A. 301 Weliwegamage, U.S.K 193 Wellappuli, N.C. 120 Weragodetenna, D. 329 Werellagama, D.R.I.B. 190 Wettasinghe, K.A. 118 Wickrama, S.M.I 236

wickramaarachchi, D. 22 Wickramagamage, P. 327 Wickramanayake, H.B.P.W. 129 Wickramanayake, I.L. 129 Wickramasinghe, A. 57 Wickramasinghe, C.S.M. 348 Wickramasinghe, W.A.L.D 193 Wickramasuriya, H.V.A. 39 Widanapathirana, L.S. 322 Wijayakulasooriya, J.V 236 Wijayasinghe, I.B 249 Wijekoon, A. 133 Wijekoon, P. 281 Wijekoon, W.M.A.M.B. 292 Wijerathne, K.M. 118 Wijerathne, M.A.D. 3 Wijeratne, S. 294 Wijesekara, P.N.K. 172 Wijesinghe, A.R.A.S. 44 Wijesinghe, K.G.G. 70 Wijesinghe, S.J. 175, 177 Wijesundara, D.S.A. 57, 60 Wijesundara, M. De S. 151 Wijesundara, N.L.S. 151 Wijesuriya, W.A.S.S.K. 148 Wijetunge, D.D.S. 153 Wijewardana, T.G. 166 Wijitadhamma, M. 341 Wimaladharma, W. M.G.I.K. 118 Wimalasinghe, E.R.R. 160 Wolseley, P. 60 Y Yakandawala, D.M.D. 70 Yaparatna, Y.M.C.D. 37 Yatigammana, S.K. 47, 65 Young, S.M. 290

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