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Task 1- ( a) (b)-[P1-D1]

• We use the "Copper" as a material in this process.

• Copper is one of the basic chemical elements. In its nearly pure state, copper is a reddish-orange metal known for its high thermal and electrical conductivity. It is commonly used toproduce a wide variety of products, including electrical wire, cooking pots and pans, pipesand tubes, automobile radiators, and many others. Copper is also used as a pigment andpreservative for paper, paint, textiles, and wood. It is combined with zinc to produce brassand with tin to produce bronze.

• The process of extracting copper from copper ore varies according to the type of ore andthe desired purity of the final product. Each process consists of several steps in whichunwanted materials are physically or chemically removed, and the concentration of copper is progressively increased. Some of these steps are conducted at the mine site itself, whileothers may be conducted at separate facilities. Here are the steps used to process thesulfide ores commonly found in the western United States.

• Mining:1. Most sulfide ores are taken from huge open-pit mines by drilling and blasting withexplosives. In this type of mining, the material located above the ore, called theoverburden, is first removed to expose the buried ore deposit. This produces an open pitthat may grow to be a mile or more across. A road to allow access for equipment spiralsdown the interior slopes of the pit.2. The exposed ore is scooped up by large power shovels capable of loading 500-900cubic feet (15-25 cubic meters) in a single bite. The ore is loaded into giant dump trucks,called haul trucks, and is transported up and out of the pit.

1. Concentrating:The copper ore usually contains a large amount of dirt, clay, and a variety of non-copper bearing minerals. The first step is to remove some of this waste material. This process iscalled concentrating and is usually done by the flotation method.

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Manufacturing process

1. Cut the billet in to the size required.

2. Inspect the sample.

3. Machining the one surface with milling m/c.

Milling m/c : a milling machine is a machine tool used for theshaping of metal and other solid materials. Its basic form is thatof a rotating cutter which rotates about the spindle axis (similar to a drill), and a table to which the work piece is affixed. Incontrast to drilling, where the drill is moved exclusively along itsaxis, the milling operation involves movement of the rotatingcutter sideways as well as 'in and out'. The cutter and workpiece move relative to each other, generating a tool path alongwhich material is removed. The movement is preciselycontrolled, usually with slides and lead screws or analogoustechnology.

4. Drilling machine : a machine for drilling, reaming, counter boring, and tappingholes ,a power machine for drilling holes in metal (as a drill press or radial drill).

About with the help of this drilling m/c will make hole of (2.5diameter) .

5. After drilling finish the hole size of 3.2515 with a good surface finish withboring operation.

Boning: An important attribute of bored holes isconcentricity. The work usually is held on a face

plate or in a chuck when boring is done in alathe. Holes formed by boring may be boredstraight, tapered, or to irregular contours. Boringis essentially internal turning while feeding thedrill or machine tool parallel to the axis of therotationof the

work piece.

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6. Drill 6 hole of size (0.53 diameter) with drilling and counter boring (0.83 diameter) depthof 0.53 dp.

7. Drilling 6 holes together With help of jigs.

Jig : A drill jig is a type of jig that expedites repetitive hole center location on multipleinterchangeable parts by acting as a template to guide the twist drill or other boring deviceinto the precise location of each intended hole center. In metalworking practice, typically ahardened drill bushing lines each hole on the jig plate to keep the tool from damaging the

jig.Drill jigs started falling into disuse with the invention of the jig borer .Since the widespread penetration of the manufacturing industry by CNC machine tools , inwhich servo controls are capable of moving the tool to the correct location automatically.

2. Skill of Labour Force?

1. Unskilled labour – Unskilled occupations are the least complex types of labour. Jobs areunskilled when persons can usually learn to do them in 30 days or less.

2. Semi-skilled labour – Semiskilled occupations are more complex than unskilled labour anddistinctly simpler than the more highly skilled types of jobs. They contain more variablesand require more judgment than do unskilled occupations. Even though semiskilledoccupations require more than 30 days to learn, the content of labour activities in somesemiskilled jobs may be little more than unskilled. Therefore, close attention must be paidto the actual complexities of the job in dealing with data, people, or objects and to the

judgments required to do the labour.

3. Skilled labour – Skilled occupations are more complex and varied than unskilled andsemiskilled occupations. They require more training time and often a higher educationalattainment. Abstract thinking in specialized fields may be required.

3. Weight :Copper Weight : it defines the number of ounce copper on 1 sq. ft. area, such as0.5, 1.0, 2.0, 3.0 oz, etc. Usually this parameter is used to specify the thickness of the copper on each layer of the board. It is very easy to work out the thickness of 1.0oz copper on 1 sq. ft. board based on the copper density (8.9 g/cm3), which is 34.29µm and rounded up to 35 µm. So we have the following list.

0.5 oz means 17.5 µm copper thickness

1.0 oz means 35 µm copper thickness2.0 oz means 70 µm copper thickness

4. Surface Finish :The use of rotating mops and pads can be an excellent way of rapidlyobtaining a good finish on copper and brass. Naturally, great care must betaken to ensure that objects are held steadily and safely, a good dust maskmust be worn and a dust extractor used if the polishing debris is not to becirculated all over the workshop. Excellent results can be obtained usingrecommended mops and polishing compounds but experience is needed toobtain the best finish that leaves no smears of the black paste that the

polishing produces.

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Makers of copper and brassware have supplied their products with a greatvariety of finishes. These are intended to increase variety and eye appealinitially and through the lifetime of the product. Many have survived over ahundred years or more of service without maintenance. Others, such as thepatina on statues erected in the outdoors, need periodic cleaning and re-protection. Early finishes were made up by the makers and frequently theformulation was kept a trade secret. Latterly they have been obtained fromproprietary suppliers.

5. Machinability:

There is no unique or unambiguous definition of the term ‘machinability’. It can beunderstood as summarizing those properties of a material that determine the ease or difficulty with which that material can be machined by various machining operationsor techniques. The machinability of a material can vary very strongly depending onthe geometry and material of the cutting tool, the machine tool and machiningtechnique used and the machining conditions. The main goal of any machining

operation is the fabrication of a work piece of the desired geometry. In view of thecomplex relationships between the numerous factors involved, it is not possible toassess machining operations in terms of one single standardized machiningcriterion. We will assess the machinability of copper and copper alloys in terms of the following four machining criteria: tool wear; chip formation; cutting forces andsurface quality. Although these four quantities are mutually interdependent, theadditional influence of factors such as the condition of the work piece material, thecutting operation, the specifics of the machine tool and cutting tool used and the roleof lubricants and cooling fluids, means that it is not possible to create a singleunambiguous machinability criterion.

6. Density :

Copper is often described as a "red" metal, though its actual color is an orange-redof lower intensity, not a bright signal red. It is not a spectral color by any means, buta particular impure one requiring its own name, such as "copper-red." The red color is produced by the density of electrons being insufficient to cause a high plasmafrequency, so the shorter wavelengths are not reflected as efficiently as the longer,redder ones. The red color is unique to copper and its alloys.

Copper has atomic number 29, atomic weight 63.57, and density 8.94 g/cc. Itsnaturally-occurring isotopes have mass numbers 63 (69%) and 65 (31%). The

electron configuration has one 4s electron outside a filled 3d shell in the groundstate. However, the energies of the 3d and 4s orbitals are about equal, so a 3d94s2configuration is as favored as a 3d104s. Copper exhibits valences +1 (cuprous) and+2 (cupric), with the +2 predominating. Copper metal has a face-centered cubicstructure, with a = 0.361 nm. Each ion has donated one electron to the Fermisphere. The work function of copper is about 4.7 eV (tabulated values vary from 3.85to 4.86). The Fermi energy is 7.0 eV. The electrical resistivity of annealed copper is1.7241 μΩ-cm, of hard-drawn, 1.771 μΩ-cm, and the temperature coefficients are0.00393 and 0.00382 per °C, respectively. For pure copper, the resistivity is 1.683μΩ-cm. The thermal conductivity is 0.923 cal/cm-s-K, and the linear coefficient of expansion is 16.42 x 10-6 per °C. The specific heat is 0.0918 cal/g-K. The meltingpoint of copper is 1083°C, boiling point 2325°C, and the heat of fusion is 50.6 cal/g.Its hardness is 3.0 on the Mohs scale.

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7. Corrosion :

Corrosion rates were quantified by measuring the corrosion site density, sizedistribution, and the electrical resistance of a probe contact with the aged surface, asa function of exposure time. A pore corrosion numerical model was used to predictboth the growth of copper sulfide corrosion product which blooms through defects inthe gold layer and the resulting electrical contact resistance of the aged surface.

8. Stress :

Stress of copper seed employing in the copper interconnection layer is studied.Since this stress affects largely the adhesion strength at the Cu/barrier layers andthe Cu(111) orientation of copper layer, reduction of stress is important. Higher andhigh stresses are applied in the layer on TaN and Ta barrier layers. These layerscan lead to poor adhesion strength. Much better adhesion strength can beaccomplished in the layer on the TaSiN barrier layer. The surface changes to roughsurfaces with annealing at 400°C in the layer deposited on TaN. The highly stressedlayer changes to a low stress layer as a result of this agglomeration. However, asmooth surface is held in the low stress layer on the TaSiN barrier layer. ©2001 TheElectrochemical Society. All rights reserved.

9. Strength :

The tensile strength of annealed copper is about 30 ksi, of hard-drawn copper, 60ksi. The Young's modulus is 16 x 106 psi.

Task 2- [P2]

1-Direct material cost: 1600 AED2-Number of component: 100 pieces3-Direct labour cost: 2600 AED

Prime cost = DMC + DLC

= 1600+2600=4200 AED

Factory cost is 30% of prime cost 4200 × 30 / 100 = 1260 AED

Factory on cost = Prime cost, Factory overhead 4200 + 1260 = 5460 AED

Factory overhead is 20% of factory cost 5460 × 20 / 100 = 1092 AED

Total cost = Prime cost + Factory cost + Factory Overhead4200 + 5460 + 1092 = 10752 AED

Profit: 10% of total cost = Profit + Total costPage 5 of 14

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= 10572 × 10 / 100= 1057.2 AED

Selling Price = Total cost + Profit= 10572 + 1057.2

= 11827.2 AED per 100 pieces

1piece = 11827.2 / 100 = 118.272 AED

Task 3-(a) [P3]

1) Advantages and disadvantages of standardization:

Advantages:

International uniformity has its own advantages. As people travel the World, theycan be assured that wherever they go the product that they buy from you will besame and that it will have the same, standard benefits. This could mean thecomponents that they buy from you in different local markets as they themselvesbecome global.

Standardization reinforces positive consumer perceptions of your product. Oneof the payoffs of great quality for a single product category is that the reputation of your product will help you sell more of it. Positive word-of-mouth pays dividends for brand owners.

Cost reduction will give economies of scale . Since you are making largequantities or the same, non-adapted product - you benefit from the advantagesassociated with manufacturing in bulk. For example, components can be bought inlarge quantities, which reduces the cost-per-unit. There are other benefits relatingto economies of scale, including improved research and development, marketingoperational costs, lower costs of investment, and in an age where trade barriersare coming down - standardization is a plausible product strategy.

Quality is improved since efforts are concentrated upon the single product. Staff can be trained to enhance the quality of the product and manufacturers will investin technology and equipment that can safeguard the quality of the standardizedproduct offering.

Disadvantages:

Although standardization in media and communication sector generated a number of advantages to both the company and consumers, the application of this concept in theindustry have its disadvantages as well, particularly on the side of the company. For

nations applying the de jure type of standardization, a single standard from thedesignated committee could have created a significant market size within a short period

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of time as compared to nations observing multiple standards. However, this type of standard may also be disadvantageous as it takes out the opportunity of other technologies from being developed ( 2000, ). Not only does this limit competition anddynamism within the industry, but this also significantly reduce the variety of technologies that end users can use.

Nations applying different types of standardization appear to experience dissimilar levels of success with some technologies. For instance, while the European Communityexperienced considerable local and global success with the GSM technology, theJapanese standards was only able to make it on the local level.

2) Asses where you will apply this concept to the component under manufacture andstate its advantages?

a) a physical dimension .

b) a measured value or physical property of a material, manufactured object, system, or service.

c) Other measured values (such as temperature, humidity, etc.).

d) in engineering and safety , a physical distance or space (tolerance), as in a truck (lorry),train or boat under a bridge as well as a train in a tunnel (see structure gauge and loadinggauge ).

e) In mechanical engineering the space between a bolt and a nut or a hole, etc...

Advantages:• Failure Rates. Based on the design model and tolerance scheme, the system

calculates the number of times per million the analyzed dimension, force or momentwill be out of tolerance.

• Probability in Tolerance: Based on the design model and tolerance scheme, this isthe likelihood that the analyzed dimension, force or moment is within tolerance.

• Percent Contribution: The amount of variation a particular dimension, constraint,force, variable or moment contributes to the probability that the analyzed item is intolerance.

• Sensitivity: The rate of change of the analyzed dimension, force or moment withrespect to a contributor. Mathematically, it is the first partial derivative of theanalyzed item with respect to a contributor. It is sometimes described as a measureof the leverage of a contributor.

• Monte Carlo is an optional statistical technique that uses random sampling tocalculate values for mean, standard deviation and probability. To more accuratelymodel the manufacturing environment, Monte Carlo analysis allows you to specify a

sample size as well as modify distribution types for contributors, choosing fromNormal, Uniform and Waybill. This approach can produce results typical of those

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found in the manufacturing process. Modifying Monte Carlo distribution types is anadvanced capability that requires manufacturing process distribution information.

• Critical Parameter Analysis applies the power of Tolerance Analysis to no geometricparameters, enabling users to rapidly analyze and gain insight into the factors thataffect performance and reliability in their designs.

• Critical Parameter Analysis aids in the identification of contributors that causevariation in performance. For example, some critical parameters that influenceperformance include response time, torque, current, force, stress, weight, velocity,inertia and temperature.

Task 3-(b) [M1]

1. what you mean by inter-changeability? A condition which exists when two or more items possess such functional and physicalcharacteristics as to be equivalent in performance and durability, and are capable of being exchanged one for the other without alteration of the items themselves, or of adjoining items, except for adjustment, and without selection for fit and performance.

The concept of interchangeability was crucial to the introduction of the assembly line at thebeginning of the 20th century, and has become a ubiquitous element of modern

manufacturing.

Interchangeability of parts was achieved by combining a number of innovations andimprovements in machining operations and the invention of several machine tools , such asthe slide rest lathe , screw-cutting lathe , turret lathe , milling machine and metal planer .

Additional innovations included jigs for guiding the machine tools, fixtures for holding thework piece in the proper position, and blocks and gauges to check the accuracy of thefinished parts. Electrification allowed individual machine tools to be powered by electricmotors, eliminating line shaft drives from steam engines or water power and allowing higher speeds, making modern large scale manufacturing possible. Modern machines tools oftenhave numerical control (NC) which evolved into CNC (computerized numeric control) whenmicroprocessors became available

2. explain the significance of interchange ability in manufacturing industry.

Since the parts are interchangeable, it is also possible to separate manufacture fromassembly, and assembly may be carried out by semi-skilled labor on an assembly line - anexample of the division of labor . The system typically involves substituting specializedmachinery to replace hand tools.

Interchange ability of parts was finally achieved by combining a number of innovations

and improvements in machining operations and machine tools , which were developedprimarily for making textile machinery. These innovations included the invention of new

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machine tools and jigs (in both cases, for guiding the cutting tool ), fixtures for holding thework in the proper position, and blocks and gauges to check the accuracy of the finishedparts.

The American System involved semi-skilled labor using machine tools and jigs to makestandardized, identical, interchangeable parts , manufactured to a tolerance , which couldbe assembled with a minimum of time and skill, requiring little to no fitting. The system isalso known as armory practice because of the history of its development by the UnitedStates Department of War in the Springfield and Harpers Ferry armories (and their insideand outside gun-making contractors). The name "American system" came not from anyaspect of the system that is unique to the American national character, but simply fromthe fact that for a time in the 19th century it was strongly associated with the Americancompanies who first successfully implemented it, and how their methods contrasted (atthat time) with those of British and continental European companies. Within a fewdecades, manufacturing technology had evolved further, and the ideas behind the"American" system were in use worldwide.

3. The influence of inter-changeability in the proposed manufacturing process.

An assembly line is a manufacturing process (sometimes called progressive assembly )in which parts (usually interchangeable parts ) are added to a product in a sequentialmanner using optimally planned logistics to create a finished product much faster than withhandcrafting-type methods. The division of labour was initially discussed by Adam Smith ,regarding the manufacture of pins, in his book The Wealth of Nations (published in 1776).

Assembly lines are designed for a sequential organization of workers, tools or machines, and parts. The motion of workers is minimized to the extent possible. All parts or assemblies are handled either by conveyors or motorized vehicles such as fork lifts, or gravity, with no manual trucking. Heavy lifting is done by machines such as overhead cranes or fork lifts. Each worker typically performs one simple operation.

According to Henry Ford:

The principles of assembly are these:

(1) Place the tools and the men in the sequence of the operation so that each componentpart shall travel the least possible distance while in the process of finishing.

(2) Use work slides or some other form of carrier so that when a workman completes hisoperation, he drops the part always in the same place--which place must always be themost convenient place to his hand--and if possible have gravity carry the part to the nextworkman for his operation.

(3) Use sliding assembling lines by which the parts to be assembled are delivered atconvenient distances.

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Simple ExampleConsider the assembly of a car: assume that certain steps in the assembly line are to installthe engine, install the hood, and install the wheels (in that order, with arbitrary interstitialsteps); only one of these steps can be done at a time. In traditional production, only one car would be assembled at a time. If engine installation takes 20 minutes, hood installationtakes 5 minutes, and wheel installation takes 10 minutes, then a car can be produced every35 minutes.

In an assembly line, car assembly is split between several stations, all workingsimultaneously. When one station is finished with a car, it passes it on to the next. Byhaving three stations, a total of three different cars can be operated on at the same time,each one at a different stage of its assembly.

After finishing its work on the first car, the engine installation crew can begin working on thesecond car. While the engine installation crew works on the second car, the first car can bemoved to the hood station and fitted with a hood, then to the wheels station and be fittedwith wheels. After the engine has been installed on the second car, the second car movesto the hood assembly. At the same time, the third car moves to the engine assembly. Whenthe third car’s engine has been mounted, it then can be moved to the hood station;meanwhile, subsequent cars (if any) can be moved to the engine installation station.

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Task 4-(a) [P4]

Shelf life:

It is the length of time that food , drink, medication , chemicals , and manyother perishable items are given before they are considered unsuitable for sale, use,or consumption . In some regions, a best before , use by or freshness date is required onpackaged perishable foods.

Shelf life is the recommendation of time that products can be stored, during which thedefined quality of a specified proportion of the goods remains acceptable under expected(or specified) conditions of distribution, storage and display. [1]

Most shelf life dates are used as guidelines based on normal and expected handling andexposure to temperature. Use prior to the expiration date does not necessarily guaranteethe safety of a food or drug, and a product is not always dangerous nor ineffective after theexpiration date.

Example:

Freshness date

A freshness date is the date used in the American brewing industry to indicate either thedate the beer was bottled or the date before which the beer should be consumed.

Beer is perishable. It can be affected by light, air, or the action of bacteria. Although beer isnot legally mandated in the USA to have a shelf life, freshness dates serve much the samepurpose and are used as a marketing tool.

Beginnings of freshness dating

General Brewing Company of San Francisco marketed their Lucky Lager Beer as "AgeDated" as early as late 1935. [17] They stamped a date on each can lid to indicate that thebeer was brewed before that date. This was not to insure that the beer was "fresh" but toinsure that it had been aged properly. So many breweries had rushed beer to marketbefore it was ready when Prohibition ended, that customers were wary of getting "green"beer. The Boston Beer Company , maker of Samuel Adams , was among the firstcontemporary brewers to start adding freshness dates to their product line in 1985. For tenyears there was a slow growth in brewers adding freshness dates to their beer. Thepractice rapidly grew in popularity after the Anheuser-Busch company's heavily marketed"Born-On dates" starting in 1996. Many other brewers have started adding freshness datesto their products, but there is no standard for what the date means. For some companies,the date on the bottle or can will be the date that the beer was bottled; others have the dateby which the beer should be consumed.

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ProcessingMain article: Filtered beer

Before a beer is bottled, it is processed to prolong its shelf life; this evidently affects thebeer's freshness date. It may be done in several ways, not all of which will be used by aparticular brewery:

Pasteurisation is a process by which a liquid is heated for a brief time to kill microbes thatmay be in the liquid. Pasteurisation has also been used for many years to keep milk safefor drinking due to bacteria that may be present.

Sterile filtration, in which the beer is passed through a mechanical filtration system whichremoves anything larger than 0.5 micrometres . This removes any yeast or hops that maystill be in the beer which would continue to react with it.

Bottle conditioning allows yeasts to remain in the beer after it is bottled. This helps preventsome oxidation of the beer.

Freshness longevity affects the time it takes a beer to become stale. Some of this dependson the type of beer ingredients included. If the beer has more hops and more alcohol thanotherwise, it will stay fresh longer than those that are not as strong.

Service life:

A product's service life is its expected lifetime, or the acceptable period of use in service. Itis the time that any manufactured item can be expected to be 'serviceable' or supported byits manufacturer .

Expected service life consists of business policy , using tools and calculationsfrom maintainability and reliability analysis . Service life is a unique commitment made bythe item's manufacturer and is usually specified as a median. Actual service life is themaximal recorded life of a product.

Example:

For maintainable items, those wear-out items that are determined by logistical analysis tobe provisioned for sparing and replacement will assure a longer service life thanmanufactured items without such planning. A simple example is automotive tires - failure toplan for this wear out item would limit automotive service life to the extent of a single set of

tires.

An individual tire's life follows the bathtub curve , to boot. After installation, there is a not-small probability of failure which may be related to material or workmanship or even to theprocess for mounting the tire which may introduce some small damage. After the initialperiod, the tire will perform, given no defect introducing event such as encountering a roadhazard (a nail or a pothole ), for a long duration relative to its expected service life which is afunction of several variables (design, material, process). After a period, the failureprobability will rise; for some tires, this will occur after the tread is worn out. Then, asecondary market for tires puts a retread on the tire thereby extending the service life. It isnot uncommon for an 80,000-mile tire to perform well beyond that limit. [2]

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It may be difficult to obtain reliable longevity data about many consumer products as, ingeneral, efforts at actuarial analysis are not taken to the same extent as found with thatneeded to support insurance decisions. However, some attempts to provide this type of information have been made. An example is the collection of estimates for householdcomponents provided by the Old House Web [3] which gathers data from the Appliance

Statistical Review and various institutes involved with the homebuilding trade.

Task 4-(b) [P4]

Shelf life is different from expiration date ; the former relates to food quality , the latter to food safety .[3] A product that has passed its shelf life might still be safe, but quality is nolonger guaranteed. In most food stores, shelf life is maximized by using stock rotation ,which involves moving products with the earliest sell by date to the front of the shelf,meaning that most shoppers will pick them up first and so getting them out of the store.This is important, as some stores can be fined for selling out of date products, and most if not all will have to mark such products down as wasted , leading to a loss of profit.

Shelf life is most influenced by several factors: exposure to light and heat , transmissionof gases (including humidity), mechanical stresses , and contamination by things such asmicro-organisms. Product quality is often mathematically modelled around a parameter

(concentration of a chemical compound, a microbiological index, or moisture content).[4]

For some foods, the shelf life is an important factor to health. Bacterial contaminants areubiquitous, and foods left unused too long will often acquire substantial amounts of bacterial colonies and become dangerous to eat, leading to food poisoning . However, theshelf life itself is not an accurate indicator to the food safety. For example, pasteurized milkcan remain fresh for five days after its sell-by date if it is refrigerated properly. In contrast, if milk already has harmful bacteria, the use-by dates become irrelevant. [2]

The expiration date of pharmaceuticals specifies the date the manufacturer guaranteesthe full potency and safety of a drug. Most medications are potent and safe after theexpiration date. A rare exception is a case of renal tubular acidosis purportedly caused byexpired tetracycline . A study conducted by the U.S. Food and Drug Administration coveredover 100 drugs, prescription and over-the-counter. The results showed about 90% of themwere safe and effective as far as 15 years past their expiration dates. Joel Davis, a former FDA expiration-date compliance chief, said that with a handful of exceptions - notablynitroglycerin, insulin and some liquid antibiotics - most expired drugs are probably effective.

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Service life is different from a predicted life, or MTTF/MTBF (Mean Time toFailure/Mean Time Between Failures)/ MFOP (maintenance-free operating period).Predicted life is useful such that a manufacturer may estimate, by hypothetical modelingand calculation, a general rule for which it will honor warranty claims, or planning for mission fulfillment. The difference between service life and predicted life is most clear whenconsidering mission time and reliability in comparison to MTBF and service life.

For example: A missile system can have a mission time of less than one minute, aservice life of 20 years, active MTBF of 20 minutes, dormant MTBF of 50 years and areliability of .999999.

A consumer item will have different expectations about service and longevity [1] basedupon factors such as use, cost, and quality.

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