Metals are electropositive chemical elements

Metals ar electropositive chemical divisors that argon char raceerised by the fol sufferinging qualities ductility, m al acee cogency, luster, opametropolis, and conductance of erupt and electricity. They give the bounce replace the hydrogen of an acid and approach pattern foots with hydroxyl radicals. assiduity is define as a cloths mass divided by its volume. Metals typic altogethery shed comparatively racy densities, patchicularly when comp ard to polymers. Often, textiles with highschool densities curtail atoms with high nuclear somas, such as gold or conk egress. However, several(prenominal) admixtures such as aluminum or magnesium sacrifice low densities. These surfaces ar useful in applications requiring a nonher(prenominal) met all toldic properties exactly in which low weight is withal beneficial.Fr shapeure Toughness keister be depict as a sensibles ability to avoid fracture, especially when a mistake is introduced. Glass, for example, has low fracture toughness (although it exhibits high strength in the absence seizure of flaws). Metals typically pass on high fracture toughness. Metals git loosely contain nicks and dents without weakening detailed a great deal. They be also impact resistant. A football game player relies on this fact to ensure that his facemask wont shatter. The roll cage on a race car, for example, is stoold from vane. This brand should remain intact in a crash, protect the driver.The ability of a framework to b terminate or strive earlier breaking is know as flexible distortion. Some substantives be planed so that they dont de build under normal conditions. You dont want your car to tip off to the east aft(prenominal) a virile west wind, for example. However, nearlytimes we dejection take advantage of ductile de organic law. The crumple zones in a car absorb energy by undergoing plastic de spurtation before they break. show takes place when take outs pull (this is known as tension), push (compression) or act in combination on a material. Once the force is employ, the material responds by distorting, counterbalancing the force. With a vauntinglyr force, there go out be a correspondingly greater distortion until the item breaks. song is the force utilise per unit of cross-sectional argona squargon to the force. This smoke be de nonative mathematically asStress (s) = pull out / unit of atomic number 18aThe metrical system units for adjudicate atomic number 18 Newton per squargon meter (N/m2) and all over-embellished system units be pounds per squargon inch (psi). air is the amount the material deforms from the unloaded posit when the force is applied. Its saying is twisting (x) = Change in continuance / trustworthy lengthSince inventory is a ratio of length divided by a length, it has no units. By the face, we fecal matter see that it represents a proportional change in size.Deformation occurs when a force is applied to a metal. T he metal is and so offered. The greater the force the much than the crookedness (strain). This relationship is recognised in Hookes Law.Hookes Law describes an plastic function where stress and strain atomic number 18 proportional (a straight line on a graph). In this region the metal acts ilk a jump-start and when the load is removed the deformation (strain) reduces and it returns to its original shape. If instead the load increases, the strain (deformation) rises and the metal undergoes uniform plastic deformation.The stress-strain graph is ignored in this region. Eventually, a maximum stress is r distributivelyed when the metal when the material reaches its limit of neck. Necking is locate thinning that occurs during rag week metal forming prior to fracture. The onset of localized necking is dependent upon the stress state which is repaired by geometric factors. Finally, bygone the maximum stress point, a point is reached where the metal sandnister no yearner sustain the load and it yields.The behavior of metals under load is a result of their atomic ar exe boxement. When a material is loaded it deforms minutely in reaction to the load. The atoms in the material move closer unneurotic in compression and further apart in tension. The amount an atom moves from its neighbor is its strain. As a force is applied the atoms change a proportional distance.This model however, does non explain wherefore there is sudden yielding. With roughly modern metals yielding usually occurs at about 1% of the nonional strength of the atomic bonds. M all materials yield at about 0.1% of the notional strength.Rather, metals exhibit such low strengths because of imperfect atomic structures in the crystallizing lattices which comprise them. A row of atoms pass on very much s bakshis mid(prenominal) crystal, creating a gap in the atomic structure. These gaps act as dislocations, which ar huge stress raising points in the metal.These dislocations move when the metal is stressed. A dislocation is defined as allowing atoms to slip one at a time, making it easier to deform metals. Dislocation interactions within a metal atomic number 18 a primary means by which metals ar de create and streng whereforeed. When metals deform by dislocation motion, the more than striperiers the dislocations meet, the stronger the metal. The presence of dislocations in metal allows deformation at low levels of stress. However, hithertotually so umteen dislocations accumulate that s tidy sumt(predicate) atoms be unexpended to take the load. This causes the metal to yield.Plastic deformation causes the formation of more dislocations in the metal lattice. This has the voltage to create a precipitate in the mobility of these dislocations due to their tendency to operate tangled or pinned. When plastic deformation occurs at temperatures low enough that atoms hobonot rearrange, the metal locoweed be strengthened as a result of this do. Unfortu nately, this also causes the metal to become more brittle. As a metal is utilise, it tends to form and grow cracks, which eventually cause it to break or fracture.Atoms of melted metal pack together to form a crystal lattice at the freezing point. As this occurs, groups of these atoms form tiny crystals. These crystals mystify their size change magnitude by increasingly adding atoms. The resulting upstanding, instead of creation a single crystal, is actually many humble crystals, called grains. These grains pull up stakes then grow until they impose upon neighbouring growing crystals. The interface amidst the grains is called a grain sn cranial orbitry. Dislocations sewernot comfor oral contraceptively cross grain boundaries. If a metal is heated, the grains fucking grow larger and the material becomes softer. Heating a metal and cooling it quickly (quenching), followed by gentle heating (tempering), results in a harder material due to the formation of many small Fe3C p recipitates which block dislocations.The atomic bonding of metals also affects their properties. Metal atoms are attached to each separate by strong, delocalized bonds. These bonds are formed by a cloud of valency electrons that are shared mingled with positive metal ions (cations) in a crystal lattice. These outer valence electrons are also very mobile. This explains why electrons abide conduct heat and electricity the free electrons are easily able to transfer energy by the material. As a result, metals contract s hale cooking pans and galvanising wires. In the crystal lattice, metal atoms are packed closely together to maximize the strength of the bonds. It is also out of the question to see finished metals, since the valence electrons absorb any photons of light smasher the metal. Thus, no photons pass through.Alloys are compounds consisting of more than one metal. Creating demoralises of metals deal affect the density, strength, fracture toughness, plastic deforma tion, electrical conduction and environmental degradation. As an example, adding a small amount of iron to aluminum will make it stronger. Alternatively, adding some chromium to steel will slow the rusting plow, but will make it more brittle. Some alloys hurl a higher subway system to corrosion.Corrosion, by the way, is a major problem with most metals. It occurs due to an oxidation-reduction reaction in which metal atoms form ions cause the metal to weaken. The pursuit technique that has been developed to combat corrosion in structural applications sacrificial anode do of a metal with a higher oxidation potential is attached to the metal. Using this operation, the sacrificial anode corrodes, leaving the structural part, the cathode, undamaged. Corrosion bed also be resisted by the formation of a protective finishing on the outside of a metal. For example, steels that contain chromium metal form a protective riseing of chromium oxide. Aluminum is also exhibits corrosion resistant properties because of the formation of a strong oxide coating. The familiar green patina formed by bullshit is created through a reaction with sulfur and atomic number 8 in the air.In nature, yet a a few(prenominal) pure metals are found. Most metals in nature exist as ores, which are compounds of the metal with oxygen or sulfur. The separation of the pure metal from the ore typically requires large amounts of energy as heat and/or electricity. Because of this large expenditure of energy, cycle metals is very important.Many metals have high strength, high stiffness, and have good ductility. Some metals, such as iron, cobalt and nickel are magnetic. Finally, at exceedingly low temperatures, some metals and in statusetallic compounds become superconductors.CeramicCeramic materials are inorganic, nonmetallic materials, typically oxides, nitrides, or carbides. Most ceramics are compounds between metallic and nonmetallic elements in which the interatomic bonds are eithe r totally ionic, or predominantly ionic but having some covalent character. age many have crystalline structures, some form glasses. The properties of the ceramics are due to their bonding and structure.The terminal figure ceramic comes from the Greek word keramikos, which means lose ones tempert stuff This signifies that the enviable properties of these materials are typically achieved through a high-temperature heat treatment cultivate. This process is called firing.Ceramics are lots defined to simply be any inorganic nonmetallic material. By this explanation, glasses are also ceramic materials. However, some materials scientists state that a true ceramic moldiness also be crystalline, which excludes glasses.The term ceramic once referred precisely to clay-es confirmationlish materials. However, containe-ass generations of ceramic materials have tremendously expanded the scope and number of realistic applications, broadening the definition signifi fucktly. Many of the se new materials have a major impact on our daily lives and on our society.Ceramics and glasses have got the pastime useful properties high melting temperature, low density, high strength, stiffness, hardness, wear opposition, and corrosion resistance. Additionally, ceramics are often good electrical and thermal insulators.Since they are good thermal insulators, ceramics posterior withstand high temperatures and do not expand greatly when heated. This makes them splendid thermal omitriers. The applications of this property range from lining industrial furnaces, to covering the stead shuttle, shielding it from high reentry temperatures.The aforementioned glasses are transparent, amorphous ceramics which are abundantly utilise in windows and lenses, as well as many other familiar applications. Light can induce an electrical repartee in some ceramics. This receipt is called photoconductivity. An example of photoconductivity occurs in fiber optic cable. Fiber optic cable is speedily replacing dogshit for communications optical fibers can transmit more information for longer distances, and have less(prenominal) interference and signal loss than traditional copper wires.Ceramics are also typically strong, hard, and durable materials. As a result, they are attractive structural materials. One earthshaking drawback to their use is their brittleness. However, this problem is organism addressed by the creation of new materials such as composites. age ceramics are typically good insulators, some ceramics can actually act as superconductors. Thus, they are use in a vast range of applications. Some (the good insulators) are capacitors, others semiconductors in electronic whirls. Some ceramics are piezoelectric materials, which convert mechanistic pressure into an electrical signal. These are extremely useful for sensors. For superconducting ceramics, there is a strong research effort to perk up new high Tc superconductors and to then develop possible ap plications. impact of crystalline ceramics is based on the radical steps which have been utilize for ages to make clay products. The materials are first selected, then prepared, formed into a required shape, and in conclusion sintered at high temperatures. Glasses, on the other hand, are typically processed by pouring while in a molten state. They are then worked into shape while hot, and terminally cooled. thither are also new methods, such as chemical vapor deposition and sol-gel processing, currently being developed. Ceramics have a wide range of applications. For example, ceramic tiles cover the space shuttle as well as our kitchen floors. Ceramic electronic devices make possible high-tech instruments for everything from practice of medicine to entertainment.There are also some special properties which a few ceramics possess. For example, some ceramics are magnetic materials and, as mentioned above, some have piezoelectric properties.The one major drawback of ceramics and glasses is that they are brittle.As mentioned above, trusted types of ceramics possess superconducting properties at extremely low temperatures. For example, there are high-temperature superconducting ceramic materials that have recently been discovered. These materials exhibit virtually no electrical resistance at a bring down place 100 degrees Kelvin. Also, these materials exhibit what is known as the Meissner effect. This means that they repel magnetic flux lines, allowing a magnet to hang in the space above the superconductor.An example of special group of crystalline ceramics is the group called Perovskites. They have captured the matter to of geologists due to the information they can yield about Earths history. The most intensely studied Perovskites at the present time are those that superconduct at melted nitrogen temperatures.Ceramics were historically employ for creating pottery and artwork, largely because the brittleness and hassle of manufacturing ceramics restr icted them from other uses until recently. However, the market requirement for microelectronics and structural composite components has risen, causing the demand for ceramic materials to managewise increase.Fiber-reinforced composites, an example of a modern ceramic application, are being created from ceramic fibers with extremely high stiffness, such as graphite and aluminum oxide.PolymersPolymers are substances which contain a large number of structural units joined by the same type of linkage. They are any of many natural and synthetic compounds, usually of high molecular weight. They typically consist of up to millions of repeated linked units, each a comparatively light and simple molecule. These substances often form into a chain- a kindred structure. Some polymers have been around since the beginning of time in the natural world. For example, starch, cellulose, and rubber all possess polymeric properties. Man-make polymers, a relatively recent development, have been studied since 1832. However, the polymer industry today has is larger than the aluminum, copper and steel industries unite.Polymers have a huge range of applications that greatly surpasses that of any other split up of material available to man. Current applications include adhesives, coatings, foams, packaging materials, textile and industrial fibers, elastomers, and structural plastics. Polymers are also astray utilise for many composites, electronic devices, biomedical devices, optical devices, and precursors for many newly developed high-tech ceramics (such as the fiber-reinforced composite mentioned at the end of the ceramic section).The word polymer literally has the heart many parts. A polymeric solid material can be considered to be one containing many chemically bonded parts or units, themselves which are bonded together to form a solid. Polymers are typically good insulators. term a large variety of polymer applications were described above, two of the most industrially impo rtant polymeric materials are plastics and elastomers. Plastics are a large and varied group of synthetic materials. They are processed by forming or borderline into shape. There are many types of plastics such as polyethylene and nylon.Polymers can be separated into two different groups depending on their behaviour when heated. Polymers with unidimensional molecules are often thermoplastic. Thermoplastic substances soften upon heating and can be remolded and recycled. They can be semi-crystalline or amorphous. The other group of polymers is the thermosets. In contast to thermoplastics, these substances do not soften under heat and pressure and cannot be remolded or recycled. Instead, they must be re toold, employ as fillers, or incinerated to remove them from the environment.Thermoplastics are typically carbon-containing polymers which are synthesized by addition or condensation polymerization. This procedure forms strong covalent bonds within the manacles and weaker molybden umary van der Waals bonds between the chains. Normally, the secondary forces can be easily overcome by thermal energy, which makes thermoplastics moldable at high temperatures. After cooling, thermoplastics will also detain their newly reformed shape. Common applications of thermoplastics include parts for familiar business firm appliances, bottles, cable insulators, tape, blender and mixer bowls, medical syringes, mugs, textiles, packaging, and insulation.Thermosets exhibit the same Van der Waals bonds that thermoplastics do. They also have a stronger linkage to other chains. Different chains together in a thermoset material are chemically held together by strong covalent bonds. The chains whitethorn be directly bonded to each other, or alternatively may be bonded through other molecules. This cross-linking between the chains is what allows the material to resist softening upon heating. Thus, thermosets must be toold into a new shape if they are to be reused or they can serve as powdered fillers.However, while thermosets are touchy to reform, they have many distinct advantages in plan design applications. These include high thermal s sheetility and insulating properties, high rigidity and dimensional stability, resistance to creep and deformation under load, and low weight. A few common applications for thermosets include epoxies (gingivas), automobile carcass parts, adhesives for plywood and particle board, and as a hyaloplasm for composites in boat hulls and tanks.The polymer molecule, a long chain of covalent-bonded atoms, is the base building block of a plastic. Polymers are typically carbon based and have relatively low melting points. Polymers have a very wide range of properties that enable them to be extensively used in society. Some uses include car parts, food storage, electronic packaging, optical components, and adhesives. synthetic substance fabrics are essentially man-made copies of natural fabrics. Synthetic fibers do not occur in na ture as themselves. They are usually derivatives of oil colour products. Examples of common synthetic fabrics are polyester, spandex, rayon, and velcro.Recent technological developments have lead to electrically conductive polymers. The behaviour of semiconductors can now be achieved with polymeric systems. For example, there are semiconducting polymers which, when sandwiched between two electrodes, can set about light of any color. This technology has the potential of leading to OLED (organic light-emitting diode) flat dialog box displays. This display would be light in weight, have low spot consumption, and perhaps be flexible.Liquid crystals are another example of polymeric materials. As the name suggests, a liquid crystal is a state of matter intermediate between a standard liquid and a solid. Liquid crystal phases are formed from geometrically anisotropic molecules. This typically means they are cigar shaped, although other shapes are possible. The polymer molecules have a certain degree of order in a liquid crystal phase. event the simplest case, the Nematic phase, in which the molecules generally point in the same direction but still move around with respect to one another as would be expected in a liquid. However, under the influence of an applied electric field, the alignment of the polymer molecules gives rise to light absorption.CompositesComposites are materials, usually man-made, that are a ternary-dimensional combination of at least two chemically distinct materials, with a distinct interface separating the components. They are created to obtain properties that cannot be achieved by any of the components acting alone.In composites, one of the materials, called the reinforcing phase, is in the form of fibers, sheets, or particles. This material is embedded in the other materials, called the matrix phase. The reinforcing material and the matrix material can be metal, ceramic, or polymer. Typically, reinforcing materials are strong with low de nsities while the matrix is usually a ductile, or tough, material.The shoot for of the composite, when it is designed and fabricated correctly, is to combine the strength of the reinforcement with the toughness of the matrix to achieve a combination of desirable properties not available in any single conventional material. The downside is that such composites are often more expensive than conventional materials. Some examples of current applications of composites include the diesel piston, brake-shoes and pads, tires and the Beechcraft aircraft in which 100% of the structural components are composites.A structural composite often begins with lay-up of prepreg. At this point, the choice of fiber will influence the basic tensile and compressive strength and stiffness, electrical and thermal conductivity, and thermal expansion of the nett pre-preg material. The cost of the composite can also be strongly influenced by the fiber selected.The resin/fiber composites strength depends prim arily on the amount, system of rules and type of fiber (or particle) reinforcement in the resin. Typically, the higher the reinforcement content, the greater the strength. There are also some cases in which glass fibers are combined with other fibers, such as carbon or aramid, to create a hybrid composite that combines the properties of more than one reinforcing material. Additionally, the composite is typically formulated with fillers and additives that change processing or performance parameters.Integrating the ceramic, metallic, plastic and semiconductor materials is a necessary requirement to the fabrication of the micro-electronics package. This is an example of a composite system whose function is to provide interface between the exchange IC (Integrated Chip) and the other items on, for example, a PCB (printed circuit board).SemiconductorsThere is a relatively small group of elements and compounds that has an important electrical property, semi-conduction, which makes them n either good electrical conductors nor good electrical insulators. Instead, their ability to conduct electricity is intermediate. These materials are called semiconductors, and in general, they do not fit into any of the structural materials categories based on atomic bonding. For example, metals are inherently good electrical conductors. Ceramics and polymers (non-metals) are generally poor conductors but good insulators. The semiconducting elements (Si, Ge, and Sn) from column IV of the day-to-day table serve as a kind of boundary between metallic and nonmetallic elements.Silicon (Si) and germanium (Ge), astray used primary semiconductors, are outstanding examples of this class of materials. These elemental semiconductors are also known as Mono Semiconductors. Binary semiconductors are formed by a compound of two elements, normally an element from group III combined with an element from group V (such as CdS), or a element from group II combined with an element from group VI (suc h as GaAs). Tertiary semiconductors are formed by a compound of three elements. These semiconductors are typically compounds of elements from groups I, III and VI (such as AgInS) or elements from groups II, IV and V (such as ZnGeAs).All materials have energy circuits in which their electrons can exist. In metals, as stated above, the valence band is partially- make full, and the electrons can move through the material. In semiconductors, on the other hand, there is a band gap that exists, and electrons cannot jump the gap easily at low temperatures. At higher temperatures, more of the semiconductors electrons can jump the gap. This causes its conductivity to go up accordingly. Electrical properties can also be changed by doping This too, is one of their great assets.Putting impurities in a semiconductor material can result in two different types of electrical behaviour. These are the so-called n (negative) and p (positive) type materials. Group V elements like arsenic added to a gr oup IV element, such as te or germanium, to produce n-type materials. This occurs due to the extra valence electron in group V materials. On the other hand, group III materials like boron produce the p-type because they have only three valence electrons. When n-type material is connected to a p-type material, the device then exhibits diode behaviour. In other words, current can flow in one direction crosswise the interface but not in the other.Diodes can act as rectifiers, but they have also led to the development of the transistor. A bipolar junction transistor (BJT) is a diode with an added third material which creates a second interface. While two npn or pnp types exist, their basic operation is essentially the same as two diodes connected to each other. With proper biasing of the voltages across each diode of the device, large current amplification can be produced. Today, metal oxide semiconductor field effect transistors (MOSFETS) have become widely used and have re put the BJT in many applications. As a result, millions of transistors can be placed on a single silicon bank check or integrated circuit. These IC chips have better reliability and scourge less power than the large vacuum tube circuits of the past.The fabrication of electronic devices from the raw materials requires two major steps. The semiconductor is first melted, and a set out crystal is used to draw a large crystal of pure, solid semiconductor from the liquid. Wafers of the semiconductor are sliced and polished. Second, the circuit pattern is engraved or deposited using a photolithographic process. The individual chips are finally segment from the initial wafer.Semiconductors experience covalent bonding. Their electrons are more tightly bound than the electrons in metals, but much more loosely bound than the electrons in insulators. The atoms in semiconductors are typically arranged in a crystal structure a diamond-like tetrahedral (in which each atom is bonded to 4 others). Semi conductors are also typically semi-shiny.The intermediate ability of semiconductors to conduct electricity at room temperature makes them very useful for electronic applications. For example, the modern computing industry was made possible by the capability of silicon transistors to act as card-playing on/off switches.Electronic computing speed has greatly increased with the integrated circuit. For example, the cycle times of todays computers are now measured in nanoseconds. Opto-electronic (laser diode) research is extending the already huge rate at which information can be transmitted.BiomaterialsA biomaterial is any nondrug material that can be used to treat, enhance, or replace any tissue, organ, or function in an organism. The term biomaterial refers to a biologicly derived material that is used for its structural rather than its biological properties. It also refers to any material, natural or man-made, that comprises whole or part of a living structure, or biomedical devic e which performs, augments, or replaces a natural function. A biomaterial can be a metal, ceramic, polymer or composite.They may be distinguished from other materials because they possess a combination of properties, including chemical, mechanical physical and biological properties, which allow them to be suitable for safe, effective and authorized use within a physiological environment. For example, collagen, the protein found in prink up and connective tissues, can be used as a nonfunctional ingredient. A second example is carbohydrates modified with biotechnological processes that have been used as lubricants for biomedical applications or as bulking agents in food manufacture.The performance of biomaterials depends on material properties, design, biocompatibility, surgical technique, and the health of patient. In particular, biocompatibility relies on the acceptance of the device by the organic structure. Ideally, there should be no irritation, inflammation, or allergic res ponseBoth biomaterials and biomechanical expertise are needed to perform in vitro scrutiny of spinal implants.Endo-vascular stents provide structural support vessels following angioplasty and other major medical procedures. After an angioplasty procedure, vessels can experience re-stenosis and eventually return to their original pre-operative diameter. In as many as 10% of the procedures, the vessels may even collapse immediately. To prevent the vessels from shrinking, endo-vascular prosthesis or stents are used. These stents are examples of biomaterials. Stents are tubular structures consisting of a spring, wire mesh or slotted tubes that are deployed wrong the vessel. Depending on the design and intended use (coronary/ peripheral), they can range in diameter from several millimeters to many times that size.A biomaterial must be typically have the following properties it must be inert or particular(prenominal)ally interactive, biocompatible, mechanically and chemically stable (o r biodegradable), processable (for manufacturability), have good shelf life, be nonthrombogenic (does not cause clot formation) if it is blood- butting, and be sterilizable.There are examples of biomaterials and compatibility problems which arise from the materials not having the above properties. These include dialysis tubing made of cellulose acetate, a commodity plastic, which is known to activate platelets and blood complement. Additionally, Dacron, a polymer widely used in textiles, has been used in vascular grafts, but only gives occlusion-free service for diameters larger than 6 mm. Finally, commercial grade polyurethanes, initially used in artificial hearts, can be thrombogenic (they cause clot formation).There are many prominent applications of biomaterials used in the medical traffic today. Biomaterials are used in orthopedics for joint replacements (hip, knee), bone cements, bone defect fillers, fracture fixation plates, and artificial tendons and ligaments. They are a lso used for cardiovascular vascular grafts, heart valves, pacemakers, artificial heart and ventricular serve device components, stents, balloons, and blood substitutes. Another application is in ophthalmics, for contact lenses, corneal implants and artificial corneas, and intraocular lenses. They can also have cosmetic applications, such as in augmentation mammoplasty. Finally, other applications include dental implants, cochlear implants, tissue screws and tacks, burn and wound dressings and artificial skin, tissue adhesives and sealants, drug-delivery systems, matrices for cell encapsulation and tissue engineering, and sutures.2).The following paragraphs will provide an analysis of the modern pop can and the considerations taken by the manufacturer in its design. The overall design of the can has several advantages over another popular drinking container, the glass bottle. The pop can is inherently light weight and cheap due to the aluminum or steel alloys that are used in its c reation. The cost of a can accounts for only about 4 cents of the hurt of a transcribed beverage. About 10 cents goes for advertising. The 12 ounces of beverage in the container typically costs less than a penny to produce. It is also not easily breakable, unlike glass.The shape of the can is easy to hold in the hand, making it much easier for a client to use. The aluminum or steel alloys of the can also have the ability to undergo expansion without breaking the container. Thus, if a pop can is frozen, it will not explode, it will simply deform. Glass, on the other hand, would not as easily deform and would likely break in this situation.Pop cans are also allow cheaper packaging methods than bottles to be used. This is because the cans can come into contact with each other without breaking, unlike bottles. This allows many cans to be transported without the need for extensive protective barriers between the individual cans. An additional feature that allows the cans to be more eas ily transported and organised is the shape of the get through and crystalise of the can. Both the bottom and enlighten have a lip. This lip protrudes upward from the top and downward from the bottom. In other words, there is a indentation in both the top and bottom of the can, as shown in the following figureThe radii of the top and bottom lips are matched so that one can is able to be stacked on top of another can. In other words, the top lip of one can fits neatly into the bottom lip of the second can. This is shown in the following diagram.This stacking feature is not possible with bottles, since the bottom base of a bottle does not resemble its top spout.The pop-top pop, with their attached tab, can provide an excellent example of inherently safer design from everyday life. When soda in cans was first introduced, a separate device was required to indeterminate these cans, and the first pop-tops represented a major advance in contrivance (and environmentalism). The initial pop-tops were sexual conquestd tear strips in the can top with attached go or levers to grasp and tear the metal tab from the can. The top was all in all removed from the can once the tab was opened, and this top was then discarded. These tabs were hence environmental hazards when discarded. Alternatively, some people would dispose of the tab by placing it into the canbefore drinking the soda. This caused the tab to occasionally be s ringowed when drinking from the can, so it sometimes had to be surgically removed. The current design of the pop-top soda can, where the tab remains an integral part of the can aft(prenominal) opening, represents an inherently safer design. While the tab can be detached by flexing it back and forward until the metal fails, this requires some additional effort to do.It is wherefore easier to use the can safely.The procedure involved in creating pop cans will now be outlined. This procedure demonstrates some of the major components of the cans.Mode rn pop cans are made from either steel or atomic number 13 using advanced engineering and sophisticated technology.There is a special grade of low-carbon steel is used for steel drink cans, which is coated on each side with a very thin layer of tin. This tin allows the surface to be saved against corrosion. It also acts as a lubricant while the can is being formed.In aluminium cans, the aluminium is alloyed with magnese and magnesium, providing greater strength and ductility. atomic number 13 alloys of different strengths and thickness are used for making the can body and the end. The reason that the alloy used from the end must be stronger than that used for the body will be described shortly.The steps involved in manufacturing cans are illustrated in a simplified way belowThe aluminium or steel strip arrives at the can manufacturing plant in huge coils.A thin film of oil is then used to lubricate the strip. The strip is then fed continuously through a cupping press that blanks a nd draws thousands of shallow cups every minute.Each cup is press through a set of tungsten carbide rings. This ironing process redraws and literally thins and raises the walls of the cans into their final can shape.Trimmers are then used to remove the flubfulness irregular edge and cut each can to a precise, specific height. The excess can material is recycled.These trimmed can bodies are passed through highly efficient washers. They are then dried-out. As a result, all traces of oil are removed in preparation for coating internally and externally.The clean cans are coated externally with a clear or pigment base coat. This coat provides a good surface for the effect inks.The cans are then passed through a hot air oven to break by dry the lacquer onto the surface.Next, a highly sophisticated printer/decorator applies the printed design in up to six colours. A surface is also applied.9.A coat of varnish is also applied to the base of each can by a rim-coater.10.The cans pass through a second oven which dries the inks and varnish.11.The inside of each can is sprayed with lacquer. This special layer is to protect the can itself from corrosion and its content from any possibility of interaction with the metal.12.Once again, lacquered internal and external surfaces are dried in an oven.13.The cans are passed through a necker/flanger. Here the diameter of the wall is reduced or necked-in. The top of the can is flanged outwards to accept the end once the can has been filled.14.Every can is tested at each ramification of manufacture. At the final stage it passes through a light quizzer which automatically rejects any cans with pinholes or fractures.15.The finished can bodies are then transferred to the warehouse to be automatically palletised before dispatch to pickaxe plant.The mint End1. ass end manufacture begins with a coil of special alloy aluminum sheet.2.The sheet is fed through a press which stamps out thousands of ends every minute.3.At the same stage the edges are curled.4.The newly formed ends are passed through a lining political machine which applies a very precise bead of compound sealant around the inside of the curl.5.A video reassessment system checks the ends to ensure they are perfect.TAB.The pull tabs are made from a narrow width coil of aluminum. The strip is first pierced and cut and the tab is formed in two further stages before being joined to the can end.6.The ends pass through a series of dies which score them and attach the tabs, which are fed in from a separate source.7.The final product is the view ased ring pull end.8.The finished ends, ready for capping the filled cans, are packaged in paper sleeves and palletised for shipment to the can filler.As mentioned above, a printer/decorator is used in the manufacturing of cans to apply a printed design in up to six colours to the can body. A varnish is then applied. A varnish is a viscid liquid, consisting of a solution of tarry matter in an oil, or a qui cksilver(a) liquid, typically laid on work with a brush. Once it is applied, the varnish soon dries, either by evaporation or chemical action, and the resinous part forms thus a smooth, hard surface, with a beautiful gloss, up to(p) of resisting, to a greater or less degree, the influences of air and moisture. The varnish therefore improves the appearance of the printed design on the can. It also increases the durability of the design by ensuring that it is more resistant to the wearing effects of the elements. This can be pronto observed through common experience.Even old, used pop cans retain their printed designs very well, despite being subjected to the elements such as moisture or air. Bottles, on the other hand, typically have paper labels attached with glue. This requires glue and paper. These bottle labels also do not possess the glossy splendour of the pop can design. Finally, they are more easily susceptible to the influences of the elements, curiously air and moisture. For example, placing a glass bottle and its label in water supply will cause the label to saturate with water. This dishonours the legibility and appearance of the label, and greatly increases the chance that it will tear or fall off the bottle. In contrast, placing a pop can in water has no effect on the legibility, appearance, or durability of the printed design.The base-coater gives the can an exterior coat to enable the printing colours to fix properly (the base coat is sometimesThe of the pop can is a separate piece to allow filling by the beverage maker prior to the top being installed.It can now be revealed why bottled beer and beer from a tap tastes different from beer in a can.Be forewarned if youre a six-pack enthusiast, youre not going to like the explanation.When you sip a can of your favorite brew, you are savoring not only fermented grain and hops but just a taking into custody of the same preservative that kept the frog you dissected in 10th-grade biology class lily-pad fresh formaldehyde.What is formaldehyde doing in beer? The same thing its doing in pop and other food and drink packaged in steel and aluminum cans killing bacteria. But not the bacteria in the drink, the bacteria that attacks a lubricant used in the manufacture of the can.Notre Dames Steven R. Schmid, associate professor of aerospace and mechanical engineering, is an expert in tribology the study of friction, wear and the lubrication applied to manufacturing and machine design. The co-author of two textbooks, Fundamentals of Machine Elements and Manufacturing Engineering and Technology (considered the password of manufacturing engineering), Schmid has conducted extensive research on the manufacturing processes used in the production of beverage and other kinds of cans.Schmid explains that back in the 1940s, when brewers and other beverage makers began putting drinks in steel (and, later, aluminum) cans, the can makers added formaldehyde to a milk-like mixture of 95 sha re water and 5 percent oil thats employed in the can manufacturing process. The mixture, called an photographic photographic emulsion, bathes the can material and the can-shaping tooling, cooling and lubricating both.Additives in the oil part are certain bacterias favorite food. But if the bacteria eat the emulsion, it wont work as a lubricant anymore. So can makers add a biocide to the emulsion to kill the bacteria.Before a can is filled and the top attached, this emulsion is moistend off, but a small residue of the oil-water mixture is inevitably left behind, including trace amounts of the biocide. The amounts remaining are not enough to be a health hazard, but they are enough to taste, and the first biocide used back in the 1940s was formaldehyde.In the decades since, can makers have devised new formulas for emulsions, endlessly with an eye toward making them more effective, more environmentally friendly and less costly. But because formaldehyde was in the original recipe, peop le got used to their canned Budweiser or whatever having a hint of the famous preservatives flavor. For this reason, Schmid says, every new emulsion formula since then has had to be made to taste like formaldehyde, or else people arent going to accept it. Extensive tests are run to make sure the lubricant and additives taste like formaldehyde.Its not that it tastes okay. Its just what people are used to tasting, he says. (Miller Genuine Draft and interchangeable brews, Schmid says, use biocides that have no flavor.)The formaldehyde flavor legacy is one little-known aspect of can-making. Another involves the smooth coating applied to the inside of cans. The rinse cycle that attempts to wash off the emulsion also aims to remove particulate matter metal debris that forms on the metals surface during the bending and shaping of a can. Like the emulsion, some of the microscopic debris always remains after rinsing. Unlike the emulsion, it can be dangerous to swallow.To keep powdered metal out of a cans contents, Schmid says, manufacturers spray-coat the inside with a polymer dissolved in a solvent. When the can is heated, the solvent boils away, leaving only the protective polymer coating.The coating not only plasters any microscopic debris to the can wall and away from the food, it keeps the food from interacting with can material, an especially important consideration with steel cans. place youve got tomato dope in this steel can. You dont want that acidic soup corroding your can. It would kill your can, and the can would adulterate your food, Schmid says. Its also why youre assured that when you go camping and you have Spaghettios you dont cook them in the can, because the polymer will degrade and youre going to be eating polymer. (Industry sources tell Schmid that the typical consequences of such a culinary blunder are headaches and constipation.)Schmid says can manufacturers are forever clear-cut for ways to improve efficiency in their struggle to stay valu e competitive with plastic and glass bottles. A single can-tooling machine can form 400 cans a minute. In a typical process, all but the top is shaped during a single stroke through a disk of aluminum or steel. The top, seamed on after filling, is made of a more expensive aluminum alloy, rich in magnesium. The added ductile strength of the magnesium is necessary so another machine can mash down a pillar of the metal to form the rivet that attaches the pop top. Todays beverage cans are necked near the top for a reason. The narrower-diameter means less of the expensive lid alloy is needed. It saves a minuscule fraction of a cent per can, but it adds up, Schmid says.In this untaught alone we use about a can per person per day, so you have to make 250 million cans per day. Its an amazing thing to watch these machines squinch out these cans.Rivet is likely a separate part from the tab. It should be strong enough to attach the tab to the can and to ensure that it does not break when the can is opened.Lip on top of can prevents liquid from flowing down the side of the can.Bottom is indented to enable stacking even when the tab has been opened. The indent provides the necessary room for the open tab.For cycle purposes, pop cans can be neatly compacted flat, and are easy to transport using a wide range of containers.Rivet is a separate piece which connects the tab to the can top.Top of the pop can is stamped with words such as recyclable and return for refund. Thus, the alloy of the top must be soft enough to allow this stamping to occur.Aluminum costs more than steel, and the price has been rising. Steel minimills now have continuous casting processes that make sheet steel thin enough to form seamless cans. And there is disceptation from other materials as well. We h ave to find ways to make cans twinkle and lighter to keep fending off polymers, steel and glass. Lighter cans means lower prices to the consumer, whos then more likely to buy cans off the grocery she lf instead of two-liter bottles or glass.ALCOAs answer is lightweighting, designing cans to use the thinnest aluminum possible within the constraints of strength and appearance.In 1993, Americans recycled 59.5 one thousand thousand aluminum cans, 3 billion more than in 1991,and raised the national aluminum can recycling rate to 2 out of every 3 cans.Aluminum can recycling saves 95% of the energy needed to make aluminum frombauxite ore. elan vital savings in 1993 alone were enough to light a city the size ofPittsburgh for 6 years.Special pallets and stacking techniques are used to protect can bodies from crushing stresses and to enable quick and efficient loading into the filling machine line.The first beverage can, filled by a brewer in Newark, New Jersey in 1935, weighed three ounces. Today, an aluminum beverage can weighs one half ounce 600% less than the original beverage can. Can manufacturers strive to do even better through a process called light weighting-the use of lighte r can ends and thinner body walls. Using less material at the beginning of the manufacturing process results in a more effective means of creating safe, reliable, performance-driven packaging. This results in less waste once the packages contents have been consumed. It also saves manufacturers money an added incentive.3).The diameter of the bar is 12.7 mm. Its universal gas constant is half the diameter. Therefore, its radius can be calculated to be (12.7 mm)/ 2 = 6.35 mm. By applying the rebirth factor that 1000 mm = 1 m, this radius can also be expressed as (6.35 mm) * (1 m / 1000 mm) = 6.35 x 10-3 m. The bar has a cross-sectional area apt(p) by the following formulaCross-sectional area = ?r2where r is the radius of the steel bar. Using this formula, the cross-sectional area of the bar can be calculated to beCross-sectional area = ?(6.35 x 10-3 m)2Cross-sectional area = 1.266768698 x 10-4 m2(Cross-sectional area = 1.27 x 10-4 m2 when significant figures are applied).Gravity ap plies a force to the bar proportional to the bars mass. This force is given by the formulaForce due to Gravity = (Mass of object) * (Acceleration of Gravity)If we assume that the steel bar is locate at the surface of the earth, the acceleration of gravity is approximately 9.8 m/s2 at this elevation. Therefore, the force applied to the bar by gravity can be calculated to beForce due to Gravity = (7000 kg) * (9.8 m/s2)Force due to Gravity = 68600 kg*m/s2(Force due to Gravity = 70000 kg*m/s2 when significant figures are applied)The stress placed on the bar is given by the following formulaStress = (force) / (unit area)Therefore, the stress placed on the bar can be calculated to beStress = (68600 kg*m/s2) / (1.266768698 x 10-4 m2)Stress = 541535326.2 kg/(m*s2)(Stress = 500000000 kg/(m*s2) when significant figures are applied)The steel bar has a modulus of walkover of 205,000 Mpa. 1 Pa is defined to be equal to 1 kg/(m*s2). Using the conversion factor that 1 x 106 Pa = 1 Mpa, 1 Mpa is d efined to be equal to 1 x 106 kg/(m*s2). We can therefore express the modulus of elasticity of the steel bar in Pa as (205,000 Mpa) * (1 x 106 Pa / 1 Mpa) = 2.05 x 1012 Pa. The strain experienced by the steel bar is the fractional deformation it undergoes when a stress is applied. This strain can be represented mathematically by the following formulawhere l represents the length of bar, and ?l represents the change in length of the bar due to the applied stress.The elastic region of the stress-strain curve refers to the portion of the curve in which an increase in stress will cause a linearly proportional increase in strain. Within this elastic region, remotion of the stress will cause the strain to be reduced to zilch as well. In other words, the material is not permanently deformed, and remotion of the stress causes the material to return to its original dimensions. The strain is therefore reversible, or elastic. In the elastic region, therefore, stress and strain can be cogitat e by a proportionality coefficient. This proportionality coefficient relating the reversible strain to stress in the elastic region of the stress-strain curve is known as the modulus of elasticity. This modulus of elasticity can be represented mathematically asModulus of Elasticity = (Elastic Stress) / (Unit Strain)This equating can be rearranged to solve for the unit strain. This rearranged equation is expressed asUnit Strain = (Elastic Stress) / (Modulus of Elasticity)Assuming the stress applied to the bar is small enough to ensure that the bar is still operating in the elastic region of the stress-strain curve, we can use the above equation to determine how much the bar will be strained by the load. Mathematically, this solution takes the following formUnit Strain = (541535326.2 kg/(m*s2)) / (2.05 x 1012 Pa)Unit Strain = (541535326.2 kg/(m*s2)) / (2.05 x 1012 kg/(m*s2))Unit Strain = 2.641635738 x 10-4(Unit Strain = 3 x 10-4 when significant figures are applied)This strain is unit less because it represents the fractional deformation of the bar when the stress is applied.