NDT abstracts~~~~~ NDT Abstracts are compiled by AEA Technology National NDT Centre, Harwell, Oxon, OX11 ORA, UK. The entries are drawn from over 500 British and International publications. Each issue concentrates on one or two subject areas.

The subjects covered in previous issues from February 1991 onwards are: Acoustic techniques for adhesive bond evaluation - 25(2); Artificial intelligence in NDT - 25(1); Characterization of ultrasonic transducers - 25(3); Gamma tomography - 24(3); Magneto-acoustic emission and the Barkhausen effect -24(1); Radiographic inspection of welds - 24(4); Ultrasonic and acoustic testing of concrete - 24(5); Vibration testing -24(2); Wire rope inspection - 24(6)

Theory and modelling of radiography

51215 Strecker, H. System configuration supported by simulation, using the example of automatic X-ray test systems (In German) Hamburg Univ. (Gennany), TIB/A92-01018/GAR, 215 pp. (1991)

The explicit representations and the estimation of the effect tolerances and other effects must be described as essential which contribute to variability in which must be taken into account in the software configuration of the picture analysis system. The work describes these problems in the concepts which support these problems in the context of an integrated modular system for the knowledge-based configuration of automatic X-ray systems. A feature of the techniques introduced is the integrating of different modelling planes of a technical system.

51059 Secretary of the Air Force; (Pinder, H.M.) Radiographic interpretation trainerltest system U.S. Patent No. 5,113,422 (12 May 1992)

This patent describes a device used during radiographic testing to simulate an aluminium structural component with a crack. The plate consists of a vinyl composition floor tiles with many holes drilled in it. A crack extends between two or more of the holes. Two sheets of plastic sandwich the floor tile for support purposes.

50866 Notea, A. Quantitative measurements for evaluation and control in total quality approach 5th Israel Materials Engineering Conference. I.M.E.C. V, Haifa (Israel), 19-20 Dec. 1990, pp. 507-512. Edited by M. Bamberger and and M. Schorr. Freund Publishing House Ltd. (1991)

A backbone of Total Quality Management is the flow of information covering all aspects of products manufacturing and service. The information is achieved by a net of measurement systems. The interpretation of the measured results involves the solution of the inverse problems. The approach described in this study is a workable solution suitable for on-line measurements. The model is based on operators described by first principles physics and on semi-empirical phenomenological functions. Examples are presented mainly from radiography and radiation gauges.

50205 Panakkal, J.P.; Ghosh, J.K.; Roy, P.R. Nondestructive characterization of mixed oxide pellets in welded nuclear fuel pins by neutron radiography and gamma­autoradiography Nondestructive Characterization of Materials, 3rd International Symposium, Saarbrucken (Gennany), 3-6 Oct. 1988. pp. 832-838. Edited by P. Holler, V. Hauk, G. Dobmann, C.O. Ruud and R.E. Green. Springer- Verlag (1989)

Nondestructive evaluation of nuclear fuel pellets after the welding of fuel pins plays a vital role in assuring a safe and reliable operation of reactors. Some of the important characteristics to be monitored in low plutonium enriched mixed oxide fuel pellets are plutonium enrichment, size of plutonium dioxide agglomerates. incorrect loading and geometric shape. Experiments were carried out at Bhabha Atomic Research Centre, Bombay on experimental fuel pins containing mixed oxide pellets of different geometry (solid and annular). of different plutonium enrichment (0-6 w% of plutonium dioxide) and containing PUO agglomerates of size 125-2000 microns to evaluate these characteristics nondestructively. Neutron radiography of these fuel pins was carried out using a swimming pool type reactor .. APSARA". Results of quantitative evaluation of the neutron radiographs and a simple model correlating neutron interaction probability and the optical density are presented. Gamma autoradiography of these fuel

NOT & E International Volume 25 Number 4/5 1992

pins showed that these parameters could be evaluated with a few limitations. This paper presents the experimental details, quantitative analysis of the radiographs by microdensitometry and merits and demerits of neutron radiography and gamma autoradiography for nondestructive characterisation of nuclear fuel pellets.

49950 Gusev, EA.; Novitskii, FN.; Potapov, VN. Scattered-background reduction in scanning an object with barrier geometry Soviet Journal of Nondestructive Testing, Vol. 27, No.9, pp. 646-650 (May 1992)

Monte Carlo methods have been applied in deriving values for parameters characterizing the scattered-background reduction behind absorbers made of iron, aluminum, and plexiglas with double slot stops for the scanning beam for X ray with Kramers spectrum.

49474 Engler, P.; Santana, M.W.; Narayanan, R. Characterization of the distribution of fluid content and porosity in reservoir cores by using digital radiography Materials Evaluation, Vol. 50, No.4, pp. 516-524 (Apr. 1992)

Digital radiography (DR) can provide measurements of one-dimensional (10) distributions of porosity and fluid saturation in reservoir cores with accuracy and precision similar to measurements by computed tomography (CT). However. DR provides a significant advantage over CT in that DR data can be acquired at least an order of magnitude faster. The ability of DR to provide accurate measurements of to, porosity. and two- and three-phase fluid-saturation distributions was investigated using an acrylic core model having drilled holes of known size and distribution. The holes were filled with either water. iodated oil. or air. Porosity and two-phase displacement of oil and in a sandstone core. Both methods produced similar results, but the CT measurements took 35 times longer. The influence of various measurement parameters on accuracy and precision was also investigated through the use of mathematical simulations and analyses of variance.

49471 Obrien, T.K.; Hooper, SJ. Local delamination in laminates with angle ply matrix cracks. Parts 1: tension tests and stress analysis National Aeronautics and Space Administration, Hampton, Virginia (United States), N91-28293/9/GAR, 33 pp. (Jun. 1991)

Quasi-static tension tests were conducted on AS4/350 1-6 graphite epoxy laminates. Dye penetrant enhanced x-radiography was used to document the onset of matrix cracking and the onset of local delaminations at the intersection of the matrix cracks and the free edge. Edge micrographs taken after the onset of damage were used to verify the location of the matrix cracks and local delamination through through the laminate thickness. A quasi-3D finite element analysis was conducted to calculate the stresses responsible for matrix cracking in the off-axis piles. Laminated plate theory indicated that the transverse normal stresses were compressive. However. the finite element analysis yielded tensile transverse normal stresses near the free edge. Matrix cracks formed in the off-axis plies near the free edge where in-plane transverse stresses were tensile and had their greatest magnitude. The fluence of the matrix crack on interlaminar stresses is also discussed.

49286 Int. Digital Modeli. Appts for nondestructively inspecting components of operating system has ring encircling component transmitting radiation through cross- section which detected, and yoke holding ring

231