Utopia Essay Summary Example For Students

Utopia Essay Summary Utopia- Lamonte Brown Copyrighted 1987Utopia was a perfect society and mostly everyone is tryig achieve their own personal utopia in some way. If a Utopia was so easy to achieve then war or famine wouldbe scarce. This is a term paper explaining just that. I aint no afaid person (ya understand). Im a rapper but Im still a gorilla (ya understand). Ill whip ya like the Thrilla Manilla (ya understand). You gon make me have to kill me a person (ya understand). We will write a custom essay on Utopia Summary specifically for you for only $16.38 $13.9/page Order now Im a be here for a minute lil wodie (ya understand). Aint bout to let nobody mess over me (ya understand). I dont need ya playa hatin on Juvey (ya understand). Dont be talkin about what you gon do with me (ya understand). Ill ride everyday of the week (ya understand). Ya get ya issue when ya playin with me (ya understand).Ill crawl at the spot that ya sleep (ya understand). Get with my people from the block and we creep (ya understand). Load it up cock it back and get ready (ya understand). Make sure you be holdin it steady (ya understand). We gon go in there and blow the switch up (ya understand). Soon as we get em we gon all get the nut (ya understand). Im still that regular, cetera cat, from the streetThuggin it, lovin my life as Memph BleekBut Im stuck with, huggin that block, sellin that DGrew up with, nothin but killas and O.G.sIm the product of the ghetto til they bag me upWith a bail stash in case they snatch me upIm a soldier in this war and I resemble my popsI aint nothin like him, thats where this criminal stopI provide for the fam, divide them gramsCook it, make flips, survival plansBein successful, I had every intentBut I went to the high school a playin the benchWe live off wit, just like our switch-up stripsI was raised by the gun so I switch up clipsGettin my hustle on, tryna switch up kicksI wont change bein thug, I wont switch up shitIts my life niggaWords/ Pages : 343 / 24

Find Out if Your Friend is a True Friend with Our Help

Find Out if Your Friend is a True Friend with Our Help Signs Someone Is A Real Friend We all have friends, but are they true or are they just actors? Below you can find some facts which will help you define whether the person is a true friend of yours or just a pathetic actor. Real friends dont blame you for choosing work over fun. You always feel free to grab some food from their fridge. You both know that if zombie apocalypse comes and someone suddenly gets bitten, you wont kill him unless he is 100% a zombie. Your friend is always ready to listen or give advice to you regardless of his mood and time of the day. Being a good friend means you can be separated for weeks or even months, but there are still no doubts about your friendship. Theyve helped you move. (If they did this during summer be sure that they are the most real friends). Friends will be always ready to help you clean up a mess after a huge party at your house. When you think everything is over for you, real friends will always support you. Each post on a social network (regardless of what it is) is commented, liked or favored by your real friend. When someone is disrespectful towards your friend, you interrupt and handle the problem. Real best friends will do the same for you. True friends are always sincerely happy for your wins and upset for your losses. Real friends will always tell you straight away when youre being stupid or inappropriate. You dont worry that your friend will post the photo where you consider yourself to be ugly. They will tell you any painful information you might not know. You always call each other stupid names or curse words. Even when dating someone, they dont forget about your friendship. They will never leave you alone. They will never be silent about your girl cheating on you. You dont need any social networks to know whom they are dating or when is their birthday, because you pretty much already know it. They wont let you do stupid stuff at least not by yourself. Being a nice person is a key to get true friends through your life. So dont lie, dont betray and dont take advantage of your friends.

How have anthropologists tried to understand depression in other Essay

How have anthropologists tried to understand depression in other societies - Essay Example According to the prediction of WHO, in 2020 depression will be the second major cause of disability (Bhugra &Mastrogianni 2004, p.13).According to Murry and Lopez (1997), ‘In developing countries major depression is projected to be the leading cause of disease burden’(as cited in Bhugra &Mastrogianni 2004, p.13). According to Kleinman and Good (1985, p.1) the terms ‘depression’, ‘melancholia’, ‘mania’ have long and continuous history in European thought. Greek and Roman writers also mentioned the presence of some ‘melancholic diseases’ among people which are similar to the ones identified today. Depressed patients are treated with medical regiments consisting of antidepressants and supportive therapies. This universal treatment of depression is of no surprise for biomedical researchers due to the fact that they consider depression to be a disease that is identifiable throughout the world. Past decades majorly contributed in identifying the biochemical and psychological factors that give rise to depression, but it does not show us the complete picture because of the recent research on neurotransmitters. Growing evidence identifies the issues about the universal perception of depression and conceptual complications. Kleinman and Good state, à ¢â‚¬ËœBioamines involved in the transmission and regulation of neurological messages-and a set of hormones are implicated in depressive illness.’ (1985, p.1) It implies to the presence of culture about depression. This essay analyses the contributions of anthropologists for understanding depression in non-Western societies. Initially depression was considered to be the issue of west only. It refers to the perception of a less evolved brain in other parts of the world (Vint 1932 as cited in Skultans & Cox 2000, p.76). Prince (1967), German (1972), and Marsella (1976) identified not only an inadequate body of research about depression when it comes to non-western societies but also found

Greek Culture pertaining to the the foods they eat Essay

Greek Culture pertaining to the the foods they eat - Essay Example Food is the essence of life for a Greek, and for generations the ritual of cooking the main family meal has been that of the woman of the household. She will begin preparing an elaborate, complicated meal often from the morning, so that it is ready when the man and the children return home from work and school. Breakfast usually consists of a strong Greek coffee (ΕÎ »ÃŽ »ÃŽ ·ÃŽ ½ÃŽ ¹ÃŽ ºÃÅ') and a bread ring (ÃŽÅ¡ÃŽ ¿Ãâ€¦ÃŽ »ÃŽ ¿Ã Ã ÃŽ ¹) and is of no particular importance. The main meal of the day is an important family event; it is where the family members (and often friends) converse around the table and communicate – most socialising is based upon eating and drinking. The main meal is often eaten late afternoon, although this depends on the season (during the summer, it will be earlier) and is traditionally followed by a one to two hour nap, after which the man will often return to work for some hours. This concerns the working hours of Greece in general, althou gh there are exceptions as always, depending again on the season or the type of work as well as whether the family lives in a major city or small village. Of course, this is just a very basic introduction as to what the food culture in Greece consists of, albeit necessary in order to progress into the more specific areas. It is safe to say, however, that the Greek food culture is one engrained through centuries of tradition, which have kept a steadfast hold of families despite our entry into the ‘modern age’. I will now explain the most popular types of foods for the Greeks and the recipes in which they can be found. Generally, the basic ingredients of Greek cuisine are not many, but each is used in a variety of ways to make very different dishes. As has already been stated, the main meal of the day is the most important. It is elaborate and usually consists of a main meat dish, along with other smaller side dishes and often some form of dip. Lamb is very popular in villages and other such rural areas,

Gulf Cooperation Council Essay Example | Topics and Well Written Essays - 500 words

Gulf Cooperation Council - Essay Example Gulf Cooperation Council was started in 1981 by the leaders of the state of Kuwait, Qatar, Bahrain, Oman, United Arab Emirates and Saudi Arabia (Rashid, 21). The purpose of the council was to promote and enhance close ties among the member states and by formulating strategies to ensure that non-GCC countries would not intimidate its members or attack them. As a result, the council engages in integration courses including peace campaigns in its member’s countries (23). The council intentions are more visible in its political activities including the diplomatic campaign to reduce tension between Oman and Yemen and to a whole range of efforts and initiatives to bring peace in Qatar, Yemen, Iraq, Iran as well as Oman. The council also helps in protection of the fundamental freedom of the citizens of its member states and stresses on the importance of GCC countries to take all the necessary measures to protect the citizens from their states. The GCC purpose towards Yemen is mainly on its deep concern for the Yemen situation and its continued condemns of the violence experienced in Yemen (Rashid 45)

Causes of Asthma

Causes of Asthma Asthma is a chronic lung disease that inflames and narrows the airways. It can be both short term and long term. Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, andcoughing. The coughing often occurs at night or early in the morning. Asthma affects people of all ages, but it most often starts during childhood. In the United States, more than 25 million people are known to have asthma. About 7million of these people are children. The airways are tubes that carry air into and out of your lungs. People who have asthma have inflamed airways. The inflammation makes the airways swollen and very sensitive, the airways tend to react strongly to certain inhaled substance. When the airways react, the muscles around them tighten. This narrows the airways, causing less air to flow into the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways might make more mucus than usual. Mucus is a sticky, thick liquid that can further narrow the airways. This chain reaction can result in asthma symptoms. Symptoms can happen each time the airways are inflamed (national institute of health). Understanding and Explaining Asthma The aetiology of asthma has been explained in terms of heredity, incitement, and induction. Incitement is the immediate broncho-constriction noted among asthmatics and others to nonspecific stimuli. Induction is the enhancement of the response to inciters that can follow exposure to certain stimuli, mostly inflammatory agents such as allergens, infections and other irritants, including industrial contaminants such as`4he plicatic acid from Western Red Cedar wood. There is a good reason to believe in a hereditary component to asthma, different components of the condition having possibly independent genetic origins. The best documented genetic component is the familial allergy to ragweed6, and Sibbald et al.7 have argued for independent hereditary components that influence atopy and bronchial responsiveness. However, migrant studies strongly suggest the major determinant to be environmental and not genetic. Both Tokeluans4 and Xhosas3 clearly have the genetic potential for developing a sthma, but this is expressed only on migrating to an economically more developed area (Journal of the Royal Society of Medicine Volume 80 June 1987 367). Isolated examples, such as the increase in asthmatics attending emergency rooms following the eruption of the Mount Helens volcano8, may be explained in terms of incitement, but there are major objections to using this mechanism as a general explanation for differences in the prevalence of asthma. The wide variety of substances capable of inducing broncho constriction in asthmatic subjects can be divided into endogenous mediators such as histamine, prostaglandins or leukotrienes, and exogenous agents such as sulphur dioxide, volcanic ash or cold dry air. For the epidemiologist attempting to explain the prevalence of asthma, the endogenous mediators are unhelpful. The discovery of a mediator whose presence distinguishes asthmatic from non asthmatic populations would be useful, but in turn would raise the question of why one population had more of the mediator than the other population. For the reason discussed above, a genetically controlled explanation can be discounted, which leaves an environmental factor to increase the amount of mediator in the asthmatic population. This is essentially the same as the initial question of what environmental factor might account for differences in the prevalence of asthma. Exogenous inciters, being environmental in origin, theoretically offer a better hope of advancing the issue further, but, in the event, are no more helpful. Differences in the prevalence of asthma are not accounted for simply by differences in the incidence of clinical symptoms provoked by environmental triggers. They also reflect differences in the under-lying prevalence of bronchial hyper-responsiveness. In van Niekerks study3, it was the response to the exercise challenge that differed between urban and rural areas. This cannot be explained simply in terms of the prevalence of inciters in the environment. Induction provides a more promising general theory with which to explain differences in prevalence. There is plenty of evidence that induction does occur, particularly in an industrial context and this has been used extensively as a general model for the aetiology of asthma. It does not, however, explain the distribution of asthma in developing countries. Agents that have been sh own to induce asthma are abundant in the Third World ( Journal of the Royal Society of Medicine Volume 80 June 1987 367). Fatality of Asthma Acute respiratory infections are probably the single most important cause of death among children. It is thus appealing to consider the hypothesis that fatal and near fatal attacks of asthma may have common causes, and that studying non-fatal asthma attacks (as well as being of value in itself) may provide useful information on the factors associated with fatal asthma attacks. Campbell investigated the levels of agreement between information obtained directly from cases of near fatal asthma attacks with those obtained independently from close acquaintances, almost all of whom were family members living in the same household. They found very high levels of agreement for recognized markers of chronic asthma severity (such as a hospital admission in the last 12 months or an intensive care unit admission), utilization of medical services, the use of prescribed agonists (although there was less agreement for other asthma medications such as oral xanthines), and psychiatric features. These findings are generally encouraging in that they indicate that information relating to these risk factors and clinical characteristics obtained from close acquaintances has reasonable reliability in studies of near fatal asthma attacks and therefore such information may also be reliable for persons dying from asthma. In contrast, information on features of the long term asthma history such as sleep disturbance and the frequency of, or trends in, symptoms in previous years was not reliable. The reliability of the reported circumstances associated with a near fatal episode was not examined. Thus, while it would seem appropriate to continue to examine deaths from asthma using clinical information that has been recorded before the fatal attack, the findings of Campbell suggests that interviews with acquaintances may provide additional useful data. Richards have compared the demographic characteristics of patients suffering fatal asthma attacks throughout New Zealand during 1980-6 with t hose experiencing severe life threatening asthma attacks in the Auckland region during 1981-7. The information avail-able for the study was limited, but the findings once again confirm the importance of a previous life threatening attack of asthma as a marker of subsequent risk of death from asthma. About one quarter of the subjects who died in Auckland during the period of the study had a previous admission to an intensive care unit with asthma. This suggests that asthmatic subjects who experience a life threatening attack are a group in whom intensive medical treatment and follow up should be arranged. These considerations indicate that, although there are some practical advantages in studying near fatal asthma attacks, there may well be greater problems of interpretation of the findings than in studies of fatal asthma. Nevertheless, when interpreted cautiously, studies of near fatal attacks may provide a useful complement to studies of fatal attacks in monitoring the time trends in severe asthma, and in identifying the causes of those changes which occur (Thorax 1993;48:1093-1094).

Unraveling Cleopatra Essay -- Egypt History Papers

Unraveling Cleopatra "She took a small boat, and one only of her confidants, Apollodorus, the Sicilian, along with her, and in the dusk of the evening landed near the palace. She was at a loss how to get in undiscovered, till she thought of putting herself into the coverlet of a bed and lying at length, whilst Apollodorus tied up the bedding and carried it on his back through the gates to Caesar's apartment. Caesar was first captivated by this proof of Cleopatra's bold wit, and was afterwards so overcome by the charm of her society that he made a reconciliation between her and her brother, on the condition that she should rule as his colleague in the kingdom." (The Life of Julius Caesar, Plutarch; translation by Dryden) Abstract Whether Cleopatra rolls out of an ornate carpet as authorative and in control or as the more stereotypical image of a sensual temptress, the carpet scene functions as an introduction between Cleopatra and Julius Caesar. More importantly, the scene also provides valuable insight into Cleopatra's character. Plutarch's account of Cleopatra's first encounter with Julius Caesar inspired countless artists to recreate their own interpretations. First prose and narratives, the workings of creative imaginations, emerged. Soon, the stirring mental images are captured on canvas and eventually breathed into cinematography. With the advent of movie making multiple versions of Cleopatra and her legend were produced, each distinct in their own right. Each version retells the carpet scene differently, and offers a different Cleopatra. The first impression of Cleopatra is imprinted by the carpet scene and sheds light on who Cleopatra is in the respective narrative or film. If she tumbles out of the c arpet in a rev... ...ert, Warren William and Henry Wilcoxen. Paramount, 1934. Cleopatra. Dir. Joseph L. Mankiewicz. With Elizabeth Taylor, Rex Harrison and Richard Burton. 20th Century Fox, 1963. Cleopatra. Dir. Robert Halmi Sr. With Leonor Varela, Timothy Dalton and Billy Zane. ABC, 1999. Dirks, Tim, "Greatest Films- Comprehensive Analysis of Classic US Films" (1996), URL: http://www.filmsite.org/cleo.html (12 Dec. 1999). Fielding, Sarah, The Lives of Cleopatra and Octavia [1757], Lewisburg: Bucknell UP, 1994. George, Margaret, The Memoirs of Cleopatra, St. Martin's Press, New York, 1997. Koller, Brian, "Cleopatra (1937)", URL: http://us.imdb.com/Reviews/165/16511 (12 Dec. 1999). Leyendecker, Frank, "Box Office On-line Review", (June 17, 1963), URL: http://www.boxoffice.com/classic.html (12 Dec. 1999). Plutarch, "The Life of Julius Caesar", Trans. John Dryden.

Powder Metallurgy

Powder metallurgy is the process of blending fine powdered materials, pressing them into a desired shape or form (compacting), and then heating the compressed material in a controlled atmosphere to bond the material (sintering). The powder metallurgy process generally consists of four basic steps: (1) powder manufacture, (2) powder blending,(3) compacting, (4) sintering. Compacting is generally performed at room temperature, and the elevated-temperature process of sintering is usually conducted at atmospheric pressure. Optional secondary processing often follows to obtain special properties or enhanced precision. 1] Two main techniques used to form and consolidate the powder are sintering and metal injection molding. Recent developments have made it possible to use rapid manufacturing techniques which use the metal powder for the products. Because with this technique the powder is melted and not sintered, better mechanical strength can be accomplished. History and capabilities The hi story of powder metallurgy (PM) and the art of metals and ceramics sintering are intimately related to each other. Sintering involves the production of a hard solid metal or ceramic piece from a starting powder. While a crude form of iron powder metallurgy existed in Egypt as early as 3000 B. C, and the ancient Incas made jewelry and other artifacts from precious metal powders, mass manufacturing of P/M products did not begin until the mid-or late- 19th century†. [2] In these early manufacturing operations, iron was extracted by hand from metal sponge following reduction and was then reintroduced as a powder for final melting or sintering. A much wider range of products can be obtained from powder processes than from direct alloying of fused materials.In melting operations the â€Å"phase rule† applies to all pure and combined elements and strictly dictates the distribution of liquid and solid phases which can exist for specific compositions. In addition, whole body mel ting of starting materials is required for alloying, thus imposing unwelcome chemical, thermal, and containment constraints on manufacturing. Unfortunately, the handling of aluminium/iron powders poses major problems. [3] Other substances that are especially reactive with atmospheric oxygen, such as tin, are sinterable in special atmospheres or with temporary coatings. 4] In powder metallurgy or ceramics it is possible to fabricate components which otherwise would decompose or disintegrate. All considerations of solid-liquid phase changes can be ignored, so powder processes are more flexible than casting, extrusion, or forging techniques. Controllable characteristics of products prepared using various powder technologies include mechanical, magnetic,[5] and other unconventional properties of such materials as porous solids, aggregates, and intermetallic compounds. Competitive characteristics of manufacturing processing (e. g. , tool wear, complexity, or vendor options) also may be c losely regulated.Powder Metallurgy products are today used in a wide range of industries, from automotive and aerospace applications to power tools and household appliances. Each year the international PM awards highlight the developing capabilities of the technology. [6] Isostatic powder compacting Isostatic powder compacting is a mass-conserving shaping process. Fine metal particles are placed into a flexible mould and then high gas or fluid pressure is applied to the mould. The resulting article is then sintered in a furnace. This increases the strength of the part by bonding the metal particles.This manufacturing process produces very little scrap metal and can be used to make many different shapes. The tolerances that this process can achieve are very precise, ranging from +/- 0. 008  inches (0. 2  mm) for axial dimensions and +/- 0. 020  inches (0. 5  mm) for radial dimensions. This is the most efficient type of powder compacting. (The following subcategories are also from this reference. )[7] This operation is generally applicable on small production quantities, as it is more costly to run due to its slow operating speed and the need for expendable tooling. oda[8] Compacting pressures range from 15,000  psi (100,000 kPa) to 40,000  psi (280,000 kPa) for most metals and approximately 2,000  psi (14,000  kPa) to 10,000  psi (69,000 kPa) for non-metals. The density of isostatic compacted parts is 5% to 10% higher than with other powder metallurgy processes. Equipment There are many types of equipment used in Powder Compacting. There is the mold, which is flexible, a pressure mold that the mold is in, and the machine delivering the pressure. There are also controlling devices to control the amount of pressure and how long the pressure is held for.The machines need to apply anywhere from 15,000 psi to 40,000 psi for metals. Geometrical Possibilities Typical workpiece sizes range from 0. 25  in (6. 35  mm) to 0. 75  in (19. 05  mm) t hick and 0. 5  in (12. 70  mm) to 10  in (254  mm) long. It is possible to compact workpieces that are between 0. 0625  in (1. 59  mm) and 5  in (127  mm) thick and 0. 0625  in (1. 59  mm) to 40  in (1,016  mm) long. Tool style Isostatic tools are available in three styles, free mold (wet-bag), coarse mold(damp-bag), and fixed mold (dry-bag). The free mold style is the traditional style of isostatic compaction and is not generally used for high production work.In free mold tooling the mold is removed and filled outside the canister. Damp bag is where the mold is located in the canister, yet filled outside. In fixed mold tooling, the mold is contained within the canister, which facilitates automation of the process. Hot isostatic pressing Hot isostatic pressing (HIP) compresses and sinters the part simultaneously by applying heat ranging from 900 °F (480 °C) to 2250 °F (1230 °C). Argon gas is the most common gas used in HIP because it is an inert gas, thus prevents chemical reactions during the operation. Cold isostatic pressingCold isostatic pressing (CIP) uses fluid as a means of applying pressure to the mold at room temperature. After removal the part still needs to be sintered. Design Considerations Advantages over standard powder compaction are the possibility of thinner walls and larger workpieces. Height to diameter ratio has no limitation. No specific limitations exist in wall thickness variations, undercuts, reliefs, threads, and cross holes. No lubricants are need for isostatic powder compaction. The minimum wall thickness is 0. 05  inches (1. 27  mm) and the product can have a weight between 40 and 300 pounds (18 and 136  kg).There is 25 to 45% shrinkage of the powder after compacting. Powder production techniques Any fusible material can be atomized. Several techniques have been developed which permit large production rates of powdered particles, often with considerable control over the size ranges of the final grain population. Powders may be prepared by comminution, grinding, chemical reactions, or electrolytic deposition. Powders of the elements titanium, vanadium, thorium, niobium, tantalum, calcium, and uranium have been produced by high-temperature reduction of the corresponding nitrides and carbides.Iron, nickel, uranium, and beryllium submicrometre powders are obtained by reducing metallic oxalates and formates. Exceedingly fine particles also have been prepared by directing a stream of molten metal through a high-temperature plasma jet or flame, simultaneously atomizing and comminuting the material. On Earth various chemical- and flame-associated powdering processes are adopted in part to prevent serious degradation of particle surfaces by atmospheric oxygen. Atomization Atomization is accomplished by forcing a molten metal stream through an orifice at moderate pressures.A gas is introduced into the metal stream just before it leaves the nozzle, serving to create turbulence as the entrained gas expands (due to heating) and exits into a large collection volume exterior to the orifice. The collection volume is filled with gas to promote further turbulence of the molten metal jet. On Earth, air and powder streams are segregated using gravity or cyclonic separation. Most atomised powders are annealed, which helps reduce the oxide and carbon content. The water atomized particles are smaller, cleaner, and nonporous and have a greater breadth of size, which allows better compacting.Simple atomization techniques are available in which liquid metal is forced through an orifice at a sufficiently high velocity to ensure turbulent flow. The usual performance index used is the Reynolds number R = fvd/n, where f = fluid density, v = velocity of the exit stream, d = diameter of the opening, and n = absolute viscosity. At low R the liquid jet oscillates, but at higher velocities the stream becomes turbulent and breaks into droplets. Pumping energy is applied to droplet form ation with very low efficiency (on the order of 1%) and control over the size distribution of the metal particles produced is rather poor.Other techniques such as nozzle vibration, nozzle asymmetry, multiple impinging streams, or molten-metal injection into ambient gas are all available to increase atomization efficiency, produce finer grains, and to narrow the particle size distribution. Unfortunately, it is difficult to eject metals through orifices smaller than a few millimeters in diameter, which in practice limits the minimum size of powder grains to approximately 10 ? m. Atomization also produces a wide spectrum of particle sizes, necessitating downstream classification by screening and remelting a significant fraction of the grain boundary.Centrifugal disintegration Centrifugal disintegration of molten particles offers one way around these problems. Extensive experience is available with iron, steel, and aluminium. Metal to be powdered is formed into a rod which is introduced into a chamber through a rapidly rotating spindle. Opposite the spindle tip is an electrode from which an arc is established which heats the metal rod. As the tip material fuses, the rapid rod rotation throws off tiny melt droplets which solidify before hitting the chamber walls.A circulating gas sweeps particles from the chamber. Similar techniques could be employed in space or on the Moon. The chamber wall could be rotated to force new powders into remote collection vessels,[9] and the electrode could be replaced by a solar mirror focused at the end of the rod. An alternative approach capable of producing a very narrow distribution of grain sizes but with low throughput consists of a rapidly spinning bowl heated to well above the melting point of the material to be powdered.Liquid metal, introduced onto the surface of the basin near the center at flow rates adjusted to permit a thin metal film to skim evenly up the walls and over the edge, breaks into droplets, each approximately the thickness of the film. [10] Other techniques Another powder-production technique involves a thin jet of liquid metal intersected by high-speed streams of atomized water which break the jet into drops and cool the powder before it reaches the bottom of the bin. In subsequent operations the powder is dried. This is called water atomisation.The advantage is that metal solidifies faster than by gas atomization since the heat capacity of water is some magnitudes higher, mainly a result of higher density. Since the solidification rate is inversely proportional to the particle size smaller particles can be made using water atomisation. The smaller the particles, the more homogeneous the micro structure will be. Notice that particles will have a more irregular shape and the particle size distribution will be wider. In addition, some surface contamination can occur by oxidation skin formation. Powder can be reduced by some kind of pre-consolidation treatment as annealing. sed for cerami c tool Powder compaction [pic] [pic] Rhodium metal: powder, pressed pellet (3*105 psi), remelted Powder compaction is the process of compacting metal powder in a die through the application of high pressures. Typically the tools are held in the vertical orientation with the punch tool forming the bottom of the cavity. The powder is then compacted into a shape and then ejected from the die cavity. [7] In a number of these applications the parts may require very little additional work for their intended use; making for very cost efficient manufacturing.The density of the compacted powder is directly proportional to the amount of pressure applied. Typical pressures range from 80 psi to 1000 psi, pressures from 1000 psi to 1,000,000 psi have been obtained. Pressure of 10 tons/in? to 50 tons/in? are commonly used for metal powder compaction. To attain the same compression ratio across a component with more than one level or height, it is necessary to work with multiple lower punches. A c ylindrical workpiece is made by single-level tooling. A more complex shape can be made by the common multiple-level tooling. Production rates of 15 to 30 parts per minutes are common.There are four major classes of tool styles: single-action compaction, used for thin, flat components; opposed double-action with two punch motions, which accommodates thicker components; double-action with floating die; and double action withdrawal die. Double action classes give much better density distribution than single action. Tooling must be designed so that it will withstand the extreme pressure without deforming or bending. Tools must be made from materials that are polished and wear-resistant. Better workpiece materials can be obtained by repressing and re-sintering. Here is a table of some of the obtainable properties. Introduction | |[pic] | | | |Powder metallurgy uses sintering process for making various parts out of metal powder. The metal powder is compacted by placing in a closed| |meta l cavity (the die) under pressure. This compacted material is placed in an oven and sintered in a controlled atmosphere at high | |temperatures and the metal powders coalesce and form a solid.A second pressing operation, repressing, can be done prior to sintering to | |improve the compaction and the material properties. | |[pic] | |The properties of this solid are similar to cast or wrought materials of similar composition. Porosity can be adjusted by the amount of | |compaction. Usually single pressed products have high tensile strength but low elongation. These properties can be improved by repressing | |as in the following table. |Material | |Tensile | |MPa | |(psi) | |Tensile | |as Percent of Wrought Iron Tensile | |Elongation | |in 50 mm    | |(2 in) | |Elongation | |as Percent of Wrought Iron Elongation | | | |Wrought Iron, Hot Rolled | |331 | |(48,000) |100 % | |30 % | |100 % | | | |Powder Metal, 84 % density | |214 | |(31,000) | |65 % | |2 % | |6% | | | |Powder Metal, repressed, 95 % density | |283 | |(41,000) | |85 % | |25 % | |83 % | | | |Powder metallurgy is useful in making parts that have irregular curves, or recesses that are hard to machine. It is suitable for high | |volume production with very little wastage of material. Secondary machining is virtually eliminated. |Typical parts that can be made with this process include cams, ratchets, sprockets, pawls, sintered bronze and iron bearings (impregnated | |with oil) and carbide tool tips. | | | |Design Considerations | |[pic] | | | |†¢ | |Part must be so designed to allow for easy ejection from the die. Sidewalls should be perpendicular; hole axes should be parallel to the | |direction of opening and closing of the die. | | |†¢ | |Holes, even complicated profiles, are permissible in the direction of compressing. The minimum hole diameter is 1. 5 mm (0. 060 in). | | | |†¢ | |The wall thickness should be compatible with the process typically 1. 5 mm (0. 060 in ) minimum. Length to thickness ratio can be upto 18 | |maximum-this is to ensure that tooling is robust.However, wall thicknesses do not have to be uniform, unlike other processes, which offers| |the designer a great amount of flexibility in designing the parts. | | | |†¢ | |Undercuts are not acceptable, so designs have to be modified to work around this limitation. Threads for screws cannot be made and have to | |be machined later. | | | |†¢ | |Drafts are usually not desirable except for recesses formed by a punch making a blind hole.In such a case a 2-degree draft is recommended. | |Note that the requirement of no draft is more relaxed compared to other forming processes such as casting, molding etc. | | | |†¢ | |Tolerances are 0. 3 % on dimensions. If repressing is done, the tolerances can be as good as 0. 1 %. Repressing, however, increases the cost | |of the product. | | | Powder Metallurgy – Processing | | | |Topics Covered | |Materials | | |Powde r Consolidation | | |Cold Uniaxial Pressing | | |Cold Isostatic Pressing | | |Sintering | | |Hot Isostatic Pressing | | |Hot Forging (Powder Forging) | | |Metal Injection Moulding (MIM) | | |Materials | |The majority of the structural components produced by fixed die pressing are iron based.The powders are elemental, pre-alloyed, or partially | |alloyed. Elemental powders, such as iron and copper, are easy to compress to relatively high densities, produce pressed compacts with adequate| |strength for handling during sintering, but do not produce very high strength sintered parts. | |Pre-alloyed powders are harder, less compressible and hence require higher pressing loads to produce high density compacts. However, they are | |capable of producing high strength sintered materials. Pre-alloying is also used when the production of a homogeneous material from elemental | |powders requires very high temperatures and long sintering times.The best examples are the stainless steels, who se chromium and nickel | |contents have to be pre-alloyed to allow economic production by powder metallurgy. | |Partially alloyed powders are a compromise approach. Elemental powders, e. g. Iron with 2 wt. % Copper, are mixed to produce an homogeneous | |blend which is then partially sintered to attach the copper particles to the iron particles without producing a fully diffused powder but | |retaining the powder form. In this way the compressibilities of the separate powders in the blend are maintained and the blend will not | |segregate during transportation and use. | |A similar technique is to ‘glue’ the small percentage of alloying element onto the iron powder.This ‘glueing’ technique is successfully used | |to introduce carbon into the blends, a technique which prevents carbon segregation and dusting, producing so-called ‘clean’ powders. | |Powder Consolidation | |Components or articles are produced by forming a mass of powder into a shap e, then consolidating to form inter-particle metallurgical bonds. | |An elevated temperature diffusion process referred to as sintering, sometimes assisted by external pressure, accomplishes this. The material | |is never fully molten, although there might be a small volume fraction of liquid present during the sintering process. Sintering can be | |regarded as welding the particles present in the initial useful shape. |As a general rule both mechanical and physical properties improve with increasing density. Therefore the method selected for the fabrication | |of a component by powder metallurgy will depend on the level of performance required from the part. Many components are adequate when produced| |at 85-90% of theoretical full density (T. D. ) whilst others require full density for satisfactory performance. | |Some components, in particular bush type bearings often made from copper and its alloys, are produced with significant and controlled levels | |of porosity, the porosity being subsequently filled with a lubricant. | |Fortunately there is a wide choice of consolidation techniques available. |Cold Uniaxial Pressing | |Elemental metal, or an atomised prealloyed, powder is mixed with a lubricant, typically lithium stearate (0. 75 wt. %), and pressed at pressures| |of say, 600 MPa (87,000 lb/in2) in metal dies. Cold compaction ensures that the as-compacted, or ‘green’, component is dimensionally very | |accurate, as it is moulded precisely to the size and shape of the die. | |Irregularly shaped particles are required to ensure that the as-pressed component has a high green strength from the interlocking and plastic | |deformation of individual particles with their neighbours. |One disadvantage of this technique is the differences in pressed density that can occur in different parts of the component due to | |particle/particle and die wall/particle frictional effects. Typical as-pressed densities for soft iron components would be 7. 0 g/cc, i. e. | |about 90% of theoretical density. Compaction pressure rises significantly if higher as-pressed densities are required, and this practice | |becomes uneconomic due to higher costs for the larger presses and stronger tools to withstand the higher pressures. | |Cold Isostatic Pressing | |Metal powders are contained in an enclosure e. g. a rubber membrane or a metallic can that is subjected to isostatic, that is uniform in all | |directions, external pressure.As the pressure is isostatic the as-pressed component is of uniform density. Irregularly shaped powder | |particles must be used to provide adequate green strength in the as-pressed component. This will then be sintered in a suitable atmosphere to | |yield the required product. | |Normally this technique is only used for semi-fabricated products such as bars, billets, sheet, and roughly shaped components, all of which | |require considerable secondary operations to produce the final, accurately dimensioned component. Agai n, at economical working pressures, | |products are not fully dense and usually need additional working such as hot extrusion, hot rolling or forging to fully density the material. |Sintering | |Sintering is the process whereby powder compacts are heated so that adjacent particles fuse together, thus resulting in a solid article with | |improved mechanical strength compared to the powder compact. This â€Å"fusing† of particles results in an increase in the density of the part and | |hence the process is sometimes called densification. There are some processes such as hot isostatic pressing which combine the compaction and | |sintering processes into a single step. | |After compaction the components pass through a sintering furnace. This typically has two heating zones, the first removes the lubricant, and | |the second higher temperature zone allows diffusion and bonding between powder particles. A range of atmospheres, including vacuum, are used | |to sinter different mate rials depending on their chemical compositions.As an example, precise atmosphere control allows iron/carbon materials| |to be produced with specific carbon compositions and mechanical properties. | |The density of the component can also change during sintering, depending on the materials and the sintering temperature. These dimensional | |changes can be controlled by an understanding and control of the pressing and sintering parameters, and components can be produced with | |dimensions that need little or no rectification to meet the dimensional tolerances. Note that in many cases all of the powder used is present | |in the finished product, scrap losses will only occur when secondary machining operations are necessary. |Hot Isostatic Pressing | |Powders are usually encapsulated in a metallic container but sometimes in glass. The container is evacuated, the powder out-gassed to avoid | |contamination of the materials by any residual gas during the consolidation stage and sealed-off. It is then heated and subjected to isostatic| |pressure sufficient to plastically deform both the container and the powder. | |The rate of densification of the powder depends upon the yield strength of the powder at the temperatures and pressures chosen. At moderate | |temperature the yield strength of the powder can still be high and require high pressure to produce densification in an economic time.Typical| |values might be 1120 °C and 100 MPa for ferrous alloys. By pressing at very much higher temperatures lower pressures are required as the yield | |strength of the material is lower. Using a glass enclosure atmospheric pressure (15 psi) is used to consolidate bars and larger billets. | |The technique requires considerable financial investment as the pressure vessel has to withstand the internal gas pressure and allow the | |powder to be heated to high temperatures. | |As with cold isostatic pressing only semifinished products are produced, either for subsequent working to sma ller sizes, or for machining to | |finished dimensions. |Hot Forging (Powder Forging) | |Cold pressed and sintered components have the great advantage of being close to final shape (near-nett shape), but are not fully dense. Where | |densification is essential to provide adequate mechanical properties, the technique of hot forging, or powder forging, can be used. | |In powder forging an as-pressed component is usually heated to a forging temperature significantly below the usual sintering temperature of | |the material and then forged in a closed die. This produces a fully dense component with the shape of the forging die and appropriate | |mechanical properties. |Powder forged parts generally are not as close to final size or shape as cold pressed and sintered parts. This results from the allowances | |made for thermal expansion effects and the need for draft angles on the forging tools. Further, minimal, machining is required but when all | |things are considered this route is of ten very cost effective. | |Metal Injection Moulding (MIM) | |Injection moulding is very widely used to produce precisely shaped plastic components in complex dies. As injection pressures are low it is | |possible to manufacture complex components, even some with internal screw threads, by the use of side cores and split tools. |By mixing fine, typically less than 20 ? m diameter, spherical metal powders with thermoplastic binders, metal filled plastic components can be| |produced with many of the features available in injection moulded plastics. After injection moulding, the plastic binder material is removed | |to leave a metal skeleton which is then sintered at high temperature. | |Dimensional control can be exercised on the as-sintered component as the injected density is sensibly uniform so shrinkage on sintering is | |also uniform. | |Shrinkage can be large, due to both the fine particle size of the powders and the substantial proportion of polymer binder used. |

Imigration essays

Imigration essays For many, immigration to the United States during the late 19th to early 20th century would be a new beginning to a prosperous life. However there were many acts and laws past to limit the influx of immigrants, do to prejudice, such as the Chinese Exclusion Act. Later on into the 20th century there would be laws repealing the older immigration laws and acts making it possible for many more foreigners to immigrate to the United States. Even with the new acts and laws that banned the older ones, no one can just walk right in and become a citizen. One must go through several examinations and tests before he or she can earn their citizenship. One man who has experienced immigrating into the United States is Charles B. Wang, an immigrant from China that has made himself a multibillion-dollar fortune in the computer industry. The Chinese Americans who originally faced extreme racism on the west cost are spread across the nation today and most have kept their culture. Many immigration laws and acts were placed against foreigners to control the influx of immigrants arriving on the American shores. The first of these was the Chinese Exclusion Act of May 6, 1882. (3,1098) Although directly affecting only a small group, it was the turning point of the U.S. immigration policies. Prior to this act no significant number of free immigrants had been barred from the country. Once the Chinese Exclusion Act had been placed, further limitations on the immigration of ethnic groups became standard procedure for more than eight decades .(3,1098) Since the arrival of the first Chinese Immigrants, racist hostility towards the Chinese always existed. (3,342) They were predominantly male laborers, concentrated in California. (3,342) They were vital to the development of western mining, transportation, and agriculture.(3,342) By 1876 enough political pressure existed to cause a congressional investigation. (3,342) An 1880 treaty gave the United State...

Childrens Depression Inventory Article Analysis

Childrens Depression Inventory Article Analysis Depression is a well-known emotional disorder that is characterized by feelings ranging from overwhelming guilt, fatigue, and social withdrawal, to irritability, abuse, and at times suicidal behaviors (Luby, 2009). Depression is not bound by age, gender, or ethnicity. Research shows that in the month of August 2009, approximately 15% of children under the age of six suffer from exceptionally high anxiety and depression levels (Jarvis, 2009). The Children's Depression Inventory (CDI) is a test often used by counselors and psychologists to assess an adolescent's symptoms of depression. Within this paper, several articles regarding the results of CDI tests will be discussed. These selected articles will also be compared, to illustrate how the results may be achieved during practical application. Furthermore, the qualifications required for administering and interpreting the CDI will be determined. Finally, the populations for which the psychological measure is valid and invalid will be distinguished, in efforts of establishing the boundaries of this psychological assessment.English: Milwaukee, Wisconsin The Milwaukee Public...Article Concerning Childhood Depression in GreeceThe first article that concerns the use of the CDI examines children with depression living in Greece. Screening for Children's Depression Symptoms in Greece, by G. Giannakopoulos (2009), gives a global perspective of the 21st century's concern with depressed youth. This article also delves into how the test's measurements are attained, and in which settings optimal results can be achieve. The setting illustrated by Giannakopoulos (2009) suggests that an academic or counseling atmosphere would be most appropriate for performing this psychological measure, and in evaluating the projected outcome. The results of this article's assessment state that depressive symptoms were being measured in children from ages 8-12, with cutoff ages above 19 or below 13 (Giannakopoulos, 2009). These findings were much lower than the studies concerning alternate countries (Giannakopoulos, 2009).The results of the CDI's 27 item questionnaire possess...

Company Report Essay Example | Topics and Well Written Essays - 2000 words

Company Report - Essay Example To prove the point, the example of Microsoft may be analyzed since it is comparatively easier to compile data owing to the transparency policy of the organization; whereby all reports and strategy objectives alongside other company deliverables are available on request. Similarly, field data may also be gathered due to research-friendly policy of the organization. Microsoft offers a diverse range of information technology applications in the ever changing industry where innovation and globalization drives the business. In this context, Microsoft is aiming at performing on a scale where digital experience for the users enhances and technology becomes more intuitive to suit the needs of humans. However, the technology outcomes have been compromised to some extent, especially with reference to newer versions of technology like cloud computing since the customers fail to encourage the sales by denying on licensing the products. This has, however, more to do with the competition where oth er smaller companies are reaching out to the clientele base with products which don`t need to be licensed since their revenue generation base differs from that of Microsoft. In this context, various recommendations can be made to Microsoft in order to improve their performance against the set objectives. To elaborate on the company`s performance, the objectives need to be discussed first. An analysis of the company`s various reports as well as on first hand interaction with various stakeholders in the company, five major objectives may be concluded; though in originality, there are a wide range of objectives set by the company. Following are five of these objectives, which seem to be gauging the major chunk of preferences of Microsoft; Establishing windows as the central platform for the entire ecosystem of the information technology world, where developers` needs may be in sync with the needs of the newer

PHILOSOPHY Essay Example | Topics and Well Written Essays - 750 words

PHILOSOPHY - Essay Example motion, number, figures, solidity etc. As such, these were termed as characteristics of something else that ultimately conveyed facts to the observer yet do not themselves relate anything substantive. Conversely, Locke also introduced secondary qualities, which one would seemingly connect with the identification of real measurable objects. These include but are not limited to sound, taste, smell, touch, etc. In this way, the reader can understand that Locke’s understanding was that primary qualities were measurable whereas secondary qualities were subjective to the individual. However, as with most theories and ways of understanding philosophy, it was not long until Locke’s position was challenged by another philosopher. As this particular case study will illustrate, George Berkeley’s contrarian view of John Locke’s understand of reality which has thus far been related. In this way, Berkeley’s main premise is that neither the primary nor the secondary qualities are sufficient for determining reality. In this way, Berkeley provides a clean break from the ideas espoused by Locke and posits instead that the ultimate measure of reality can only be understood as a function of the ideas that sensations create within the mind of the individual. Whereas Locke sought to differentiate between subjective and objective measurements of reality, Berkeley posits that reality as a construct can only exist in the subjective realm. Due to the fact that no two individuals will behave the same way with regards to given stimuli, as a result of life experience and a host of other factors, it is similarly inconceivable, according to Berkeley, that they will approach reality from the same way and with the same results. Ultimately, Berkeley saw that once the object itself was stripped of its secondary qualities, i.e. the qualities that gave it measurable meaning to the individual, it became increasingly difficult, if not