Kantian and Utilitarian free essay sample

Kant believed in an absolute moral law that he called the Categorical Imperative. It is this imperative that determines our duty. (2) Two formulations of this imperative can be used to determine the morally correct action that Alistair should choose. The first formulation, The Formula of Universal Law: Act only on that maxim through which you can at the same time will that it should become a universal law [of nature]. (2) Alistair has two possible maxims to act upon. These maxims, if it were universally applicable, are: â€Å"Anyone may lie in order to promote increasing human welfare† and â€Å"Everyone always tells the truth†. The first maxim is contradictory. If people had the option to lie, it negates the system of trust on which the world is built. When, for example, I put my money in the bank, I trust them to keep it safe. If the first maxim was universally accepted, I could not trust without reservation that the bank would keep my money safe because they would be able to give my money away if they felt it would increase the welfare of those less fortunate. We will write a custom essay sample on Kantian and Utilitarian or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page If this was the case, there would be widespread mistrust and, ironically, it would have a negative impact on human welfare. The second maxim is universally applicable and is thus, according to Kant, the maxim on which to act upon. The second formulation, The Formula of the End in Itself: â€Å"So act as to treat humanity, both in your own person, and in the person of every other, always at the same time as an end, never simply as a means. †(2) If Alistair were to withhold the truth about the bribery, he denies the rationality of the board and denies that there is any rational action for them to perform. He denies them the option to rationally make a decision on what to do about the situation. In doing this he is using the board merely as a means to ensure the delivery of the medicine. According to Kant, for Alistair to use the board as a means in themselves, he would have to tell the truth. According to Kant’s theory, the action of ignoring the bribe fails the first and second formulation of the Categorical Imperative, thus the right thing to do would be to tell the truth to the board of directors. Utalitarian Theory Looking back at the case study it is clear that, on the one hand, people are receiving inexpensive kits of medicine, the drivers don’t get shot and the reputation of the relief organisation and the director is still intact. On the other hand, the board doesn’t know about the bribery, thus the unethical activity cannot be put to a stop. Utilitarianism is a theory based on consequences, not the action leading to the consequence. This theory holds that we should choose those actions that would result in the greatest amount of good in the interest of the greatest number of people affected by our actions. 1)(4) The â€Å"good† is anything that, directly or indirectly, brings happiness or pleasure. (4) The consequences of each particular action is considered to determine which outcome will best serve the greater good. (3) Act Utilitarianism prescribes that every situation be evaluated independently. The action that leads to the greatest net outcome of utility is then c onsidered to be the correct choice. According to this theory, Alistair should choose the action that will maximise happiness and minimise unhappiness. Alistair has two possible choices with two different consequences. The first is that Alistair tells the truth about the bribery. The possible outcome of his choice are the following: the drivers stop receiving cash and get shot, the contract is terminated and the less fortunate stop receiving their medicine, the director in charge of the contract is fired, and the relief organisation suffers great embarrassment. These are all negative effects and cause great unhappiness. On the other hand, the happiness of the board is increased because they can put a stop to more unethical activity. The second choice that Alistair has to consider is to keep silent and overlook the bribe. This would lead to the situation staying the same (as stated in the case study) and would secure the happiness of the greater good which include: the director, the relief organisation, the drivers and the people receiving the medicine. The board of directors would not know about the bribe, so there would be no unhappiness to consider. Considering the consequences of both actions, the happiness of the greater good is maximised when Alistair keeps silent.

Otto von Bismarck essays

Otto von Bismarck essays Otto von Bismarck was born at Schonhausen on I April 1815. Bismarck came from a Pomeranian Junker family. Bismarck grew up in the powerful German state of Prussia. When Bismarck was young, he was a big man due to eating and drinking too much; he was always ready for a duel. Bismarck wore a full beard for long periods of his life. Bismarck went to the best Berlin grammar school; then he went to study laws at the University of Gottingen in Hanover and University of Berlin. After qualifying the examination, Bismarck entered Prussian civil service and became a judicial administrator at Aachen. His career in the civil service was not a success. Bismarck served there for a short period of time. When he finished serving Bismarck was 24. Bismarck married with Johanna von Puttkamer when he was 30. Bismarck believed that he shared the same belief with the God in making Prussia strong and in unifying Germany; he had once said, You would not have had such a Chancellor if I had not the wonderful basis of religion (21). In 1847, Bismarck became a member of the united diet. Bismarck opposed every liberal proposal. In 1848, the ideals of French Revolution spread to Germany. There was a popular uprising of liberals in Germany. Conservative Bismarck opposed the liberal revolution in 1848. In 1851, Bismarck gained prominence and was chosen to become the Prussian delegate to the Federal diet when he was 36. During the Crimean War, Bismarck convinced the government to refuse to mobilize army of the German Federal diet to help Austria in Balkans. Bismarck saw no point to help Austria: I dont recognize any right in foreign policy (29). Bismarck also worried that it might alienate other countries. Thus, Prussia stayed neutrality. During the 1850s, Bismarck served Prussia as a diplomat at the Frankfurt Diet of German states. During his years at Frankfurt, Bismarck only concerned about the conflict wi...

Patriot Act Research Paper Example | Topics and Well Written Essays - 1250 words

Patriot Act - Research Paper Example Though there is some opposition to this act, with the opponents arguing that it has some abuse on the civil liberty and discourages free speech (Mascaro, W06). The opponents also argue that the act jeopardizes the privacy and the freedom of the American citizens, by legalizing the surveillance of their private life activities by the government. However, this notwithstanding, the act has gone a long way in ensuring the safety of the American people against terrorist attacks. Through the ability to intercept telephone lines and internet messages, the act allows the government to spy all the activities of the terror groups and individuals, and serve to apprehend those involved in such plans, just before the attack is full-blown (Mac Donald, 23). The act has many other provision all meant to guard against the planning and execution of criminal and terror attacks within the US and its other areas of Jurisdiction. Under this section 215 of the Act, the director of Federal Bureau of Investi gations (FBI) or a designee of the director may make an application for an order requiring the suspected individuals to produce anything tangible may it be books, papers, documents, for use in investigation against international terrorism (Mac Donald, 11). Such applications are to be made to a judge, who then grants the director such orders authorizing the suspect to produce such tangibles. However, such orders shall not disclose that they are issued for such investigations (Steranko, 36). The information that the FBI has sought such tangibles is not to be disclosed by any one, the person from whom they are sought inclusive. This section has served to protect the lives of the American people against terrorism. This is because, it allows the intelligence agencies to investigate suspected terrorists well in advance and that guard against a likelihood of them organizing and perpetrating terrorist attacks (Keller, A2). For example, this section allows the FBI to wiretap communication or obtain an order to search a home of an individual they suspect is an agent of foreign power, or a member of a terror network, without prior notice of search a search to the individual. The only concern the opponents raises is that there is no adequate protection against such violations occurring in the future. The section has effectively eliminated the limitations associated with specific target people and group from whom the materials and information is to be sought, since it is not possible to predict who the terrorist and the criminals are. By providing for the acquisition of such information from any one and any place, the provision ensures a complete coverage of all areas that are likely to be sources of terrorist threats, even when such sources are disguised. This is important, since libraries and bookstores can be a vital source of information for the terrorists and criminals. Section 805 of the Patriot Act makes provisions, which makes any offer of material support to terro rist or terrorist organizations in the US illegal (Mascaro, W06). The definition of crime under this section is broadened to illegalize the provision of support to include monetary instruments, financial securities, and any form of expertise advice or assistance (Steranko, 38). This section has served to protect the American people from terrorist attack, through ensuring that no support is obtained domestically by the terrorist from their terror networks or

Customized Competitive Intelligence in International Environment Essay

Customized Competitive Intelligence in International Environment - Essay Example The authors believe that it is a continuous process of assimilating environment information about the changing socio-cultural and political environment within which business operates. Businesses fail not because of lack of competency and financial backup but because of failure to exploit the cultural competencies of the new market and market paradigms. The qualitative research has used wide array of literature and interview with 12 CI consultants, working in different countries to provide guidelines and approach for effective CI. CI is primarily the methodology of gathering of information about the changing business paradigms across the countries with business potential. It provides the business with strong database of knowledge that can be judiciously exploited to gain and maintain competitive advantage. CI is a complex process and must be understood within the broader context of varying socio-cultural, political and legal imperatives of the nations. The understanding of various ext ernal factors facilitates in collecting relevant and authentic information that can be exploited by businesses for sustainable growth across globe. Research has analyzed CI practices for developed and developing nations where the scope of expansion exists for US firms which are as follows: 2. CI in developed countries Applications of CI practices are different for myriad reasons which are distinct in their perspectives vis-a-vis culture, technology, political and legal environment etc. 2.1 Europe European Union has huge market potential but cultural diversity across nations necessitate cross cultural understanding. Business must use different strategies to glean information about businesses in different European nations. Telephonic and email is acceptable and cost effective means of communication. Face to face interview should only be followed for competitors. Language barrier is important factor and native language, wherever possible, should be used to gain trust. CI practitioners must flexible in their approach and be prepared for differences in opinions. They must also corroborate data from wide sources. Last but not the least important is that 2-3 weeks before and after main holidays must be avoided as Europeans tend to focus on their holiday plans or busy finishing their backlog. 2.2 Japan Japan has maintained its technological superiority in digital goods like camera, electronics goods etc. in the international market. Government facilitates CI support to its domestic businesses which, unfortunately, they do not exploit due to lack of analytical tools. But at the same time, it also offers huge business potential for international firms. Due to government support to CI practices, Japan lacks publicly available data regarding businesses. CI practitioners should therefore, focus on developing trust which is critical factor in Japanese culture and use social networking to collect information. 3. Developing countries These are emerging markets which offer hug e scope of business opportunities for international businesses. Due to socio-cultural diversity and different political systems across emerging economies, CI practitioners need to be discriminatory in their approaches while gathering information. 3.1 China It is one of the most important and fastest growing economy which uses CI approach to exploit new opportunities across the globe. There is huge competition in the Chinese market which makes CI practices an intrinsic part of

China,Japan and Korea Essay Example | Topics and Well Written Essays - 1000 words

China,Japan and Korea - Essay Example This form of government was in existence since 1644 to 1911 and it had a number of dynasties, for instance Xia, Shang and Tang (ChinaI 2). Though this form of system was in existence for a long period, it had a number of faults that were the main reason for its fall. According to historical studies, some of the problems associated with this form of political system were that it was marred with not only nepotism but also corruption (ChinaI 11). For instance, court officials themselves were corrupt to the extent of planning intrigues against one another. Citizens were levied high amounts of money in form of taxes that the government spent on undertaking expensive military expeditions. Another example of the poor political system emerged during Mao Zedong era. Mao’s form of government was quite dictatorial that no one would dare oppose his opinions. Since not everyone loved Mao’s form of governance, this resulted to the Cultural Revolution in 1966 that lasted for one decade (ChinaVI 3). During the revolution, Chinese students openly criticized the government. The case was similar during Deng Xiaoping reign whereby students were also unhappy with the form of governance, hence held protests in Tiananmen Square. After turning down the order to vacate the square, Deng sent an army to disrupt the protest that resulted to massive loss of lives, most of whom were students (ChinaIV 18). Just like China, Japan also had numerous issues due to poor ancient political systems. Historically, the Togukawa government ruled Japan. The system comprised of shogun, daimyo and the samurai (Japan V 3). Apart from collecting taxes, the Togukawa government also had the task of controlling cities in addition to maintaining civil order. Japan had both formal and informal institutions; informal institutions comprised of Zoku and Amakudari. Whereas Zoku was a policy tribe comprised of politicians working together for a

Tribological Audit Of Rolling Element Bearings

Tribological Audit Of Rolling Element Bearings 1. INTRODUCTION: In the current scenario, conservation of material and energy is very much important. As the principal cause of material wastage is wear, any reduction in wear leads to savings. Friction is the main cause of wear which leads to energy dissipation and damage to equipments. [1] Friction occurs when one surface drags upon another surface. The magnitude of frictional force depends upon the interaction of mating surfaces. All surfaces consist of minute asperities and depressions even though the surface has high degree of finish. From close observation it is clear that frictional force is produced due to the distortion of the micro asperities when one surface slides over the other. As most of the surfaces are elastic up to a limit, the original shape is regained afterwards. In extreme cases the asperities get removed due to plastic flow of materials. [4] This process of removal of material from one or both of two surfaces in contact is known as wear. [6] Lubrication is the most effective me thod to lower the friction and to control wear and tear. Lubrication is the process of interposing a solid liquid or gaseous lubricant in between two surfaces in relative motion in order to decrease wear and tear. [6] Tribology is the science of interacting surfaces in relative motion and of related subjects and practices. [5] Tribology is derived from the Greek word Tribos which means rubbing. It deals with relative motion of the bodies, friction, wear and lubrication. The motion of the bodies includes sliding, rolling, spinning, bouncing or combination of these. [5] The written history of tribology is as old as about five thousand years. In olden days itself people were concerned about friction and the ways to reduce it. Assyrians used rollers made of wood to move massive stones. [2] Later carts are developed as rolling friction is less than sliding friction. Although the ways to reduce friction was highly concerned from the olden days itself, the word tribology was introduced in 1966. [5] The minimum film thickness in tribological machine elements was in the order of 10 µm to 100 µm at the start of the century. Later advance in the tribology led to the development of components with film thickness up to 1 µm. The thickness is further reduced to 0.1 µm by the end of the century. In short, tribolo gy in the important factor in design of machine elements and selection of lubricants. [5] 2. ROLLING BEARINGS: Invention of wheel led to minimise the effort of moving an object as rolling friction is less than that of sliding friction. Even though rolling motion produces less friction, man was seeking different ways to decrease the rolling friction. This led to the discovery that bearing based rolling motion consumes less power. Hence it was implemented in all rolling systems including complex machine mechanisms. In earlier periods the roller bearings was not able to compete with the hydrodynamic sliding bearings as it cannot meet with the endurance characteristics of the other. The roller bearing was universally accepted in the 20th century by the development of superior bearing materials and advanced techniques. This helped to manufacture roller bearing assemblies with extreme accuracy and long life. The competition among the manufacturers increased in early 1970s which led to a sudden increase in the production of high quality products at relatively low costs. [2] Rolling bearing includes all types of bearings to permit minimum friction between two moving surfaces relative to one another. The main application of roller bearing is to rotate a shaft relative to some fixed or oppositely rotating structure. It also allows relative linear motion of a fixture in a fixed direction provided by a stationary shaft. [3] Usually a bearing consists of two steel rings each of which consists of a hardened raceway. The hardened steel balls or rollers roll in these raceways. These rolling elements are usually held in an angular spaced structure which is called separator or retainer. [2] ball.gif Figure 1- Ball Bearings [7] There are different types of roller bearings based on their analysis of operation. A brief description on various types of bearings is explained below. 2.1 BALL BEARINGS: 2.1.1 Radial Ball Bearings: Radial ball bearings are the most popular rolling bearings. This type of ball bearings has an inner and outer raceway grooves in between the balls are inserted. The grooves have curvature radii of about 53% of the size of the ball diameter. The inner groove is concentrically fixed inside the outer groove and the ball bearings are present in between the grooves. The bearings are separated uniformly. A cage is used to maintain the separation. Deep groove ball bearings have the capacity to carry more loads as it is having large ball diameter. It can carry radial as well as thrust loads. Seals are present to keep the lubricant in and protect from external dirt. [2] Figure 2- Radial Ball Bearings [8]radial-bearings.jpg 2.1.2 Angular Contact Ball Bearings:406px-Angular-contact-ball-bearing_single-row_din628_type-b_120.png Angular contact bearings are designed to withstand heavy thrust loads or a combination of both thrust and radial loads. The ball bearings have a contact angle which does not exceed 40 degrees. Single and double row ball bearings are usually used depending upon the nature and magnitude of force to withstand. In this type of ball bearings, the outer raceway is the part of a sphere. The load applied on the outer raceway is minimised as the balls do not conform well into it. By using large balls the load on each ball can be minimised. This type of bearings can be used in applications where the parallelism of shaft and the housing are not exact to each other. [2] Figure 3- Angular Contact Ball Bearings [9] 2.1.3Thrust Ball Bearings: thrust-ball-bearing_din711_ex.png Thrust bearings are those bearings having a contact angle of 900 which can withstand thrust loads. These types of bearings are meant for high speed applications. The thrust bearings are mounted on spherical seats to obtain high degree of alignment ability. These bearings cannot be used to hold any radial loads. [2] They are mainly used in automotive, marine and aerospace applications. These increase smoothness and help in noise reduction thereby reducing friction in the attached part. Small size, reduced friction and long life are the main advantages of thrust bearings. [10] Figure 4- Thrust Ball Bearings [11] 2.2 ROLLER BEARINGS: Roller bearings are used in applications where the bearings have to support very high loads. Rollers are used in these bearings instead of balls. In these roller is cylindrical in shape and so line contact is formed between rollers and raceways. This spreads the load out a large area. Hence they have more load supporting capability. [12] They supply more fatigue endurance than ball bearings. Also the cost of manufacturing is high. These bearings consist of two concentric raceways which consist of rollers in between the two. To increase the load carrying capacity, cylindrical bearings with two or more rows of rollers are constructed. Different types of roller bearings include needle roller bearings, tapered roller bearings, thrust roller bearings and spherical roller bearings. [2] Roller-Bearing.jpgLB_OP_Linear_Motion_Bearing_250x250.jpg Figure 5- Roller Bearings [13] Figure 6- Linear Motion Bearing [14] 2.3 LINEAR MOTION BEARINGS: Linear motion bearings are the recent products developed in order to provide free motion in one dimension. In machine tool slide ways, very high friction is developed. Linear motion bearing consists of balls which carry the loads laterally in a particular direction and hence wear and tear can be minimised. They provide smooth, precision, guiding surface. The rolling element of a linear bearing rides over it thereby reducing friction. [15] 3. TRIBOLOGICAL FACTORS: Tribology deals with friction, wear and lubrication. The two key factors related to tribology are interacting surfaces and relative motion. It is clear that tribology is concerned with two surfaces in relative motion which are adequately close to one another. Usually a poor tribological interface is designed and then various lubricants are used to lower the friction between the surfaces. The most acceptable way is to design a better interface which includes the selection of a good lubricant also to minimise the friction and wear to the lowest. [5] Various tribological factors are to be taken into consideration while taking a situation. The important tribological factors include: Material Surfaces Lubricants Operating Conditions [5] 3.1 MATERIAL: The initial step to be taken while designing a product is the material selection. There are various factors which are taken into consideration while selecting the material. For tribological point of view the following factors are to be given importance before material selection. Basic Mechanical Properties Friction Wear Resistance Compatibility [5] 3.1.1 Basic Mechanical Properties: The basic mechanical properties of the material such as elastic modulus, Poissons ratio, yield stress, hardness, fatigue resistance, ultimate tensile strength and thermal conductivity are to be analysed. [5] Also the availability and cost of the material are also taken into account. Based on these observations the best material suitable for the manufacturing of bearings is selected. The selection of material used for bearings is to be done carefully based on standard specifications. The material plays an important role in the performance of the bearings. This affects the overall performance of the machinery also. The selected material is used to manufacture the load bearing parts of the bearings like raceway grooves and balls or rollers only. Retainers and cages are made from some other soft materials with desired qualities. [17] 3.1.2 Friction: Friction is the resistance offered by two interacting surfaces in relative motion. The degree of friction is denoted by coefficient of friction  µ. [6] Friction occurred during sliding is known as sliding friction and which occurred during rolling is known as rolling friction. The main factors which cause friction are adhesion between surfaces, surface hardness, asperities etc. [6] 3.1.2.2 Laws of Friction: There are different laws of friction which are applicable to dry friction between interacting surfaces. The first and second laws were put forward by Leonardo da Vinci and third law was introduced by Coulomb. [6] The first law of friction states that force required to initiate or sustain sliding FT is proportional to FN, the normal force. [6] Thus FT ÃŽ ± FN or FT =  µ.FN [6] Where  µ = Coefficient of friction The second law of friction states that the friction force FT is independent of the apparent area of contact Aa [6] The third law of friction states that friction is independent of sliding speed. [6] It was found that the first two laws of friction are obeyed in almost all experimental conditions. Lubrication systems can be used to lower the friction developed within the bearings. Friction in bearings depends upon the viscosity of lubricant and shear rate. Self lubricated bearings are widely used as it offers only very low friction. [20] 3.1.3 Wear: Wear can be termed as the material loss or volume loss from the surface of the materials in contact. [21] The main types of wear occurring on material surfaces are adhesive wear, abrasive wear, fatigue wear, corrosive wear. The local pressure at the asperities becomes extremely high when the normal pressure is acted upon the mating surfaces. When the pressure exceeds a certain limit, the asperities deform plastically until the area of contact increased sufficiently to withstand the load. The wear produced due to adhesion process has been explained by Archard equation. Wad = K [22] Where Wad = wear rate K = wear coefficient F = normal load H = hardness of softer material When two dissimilar materials slide over one another, the softer material gets scratched away. Thias type of wear is called as abrasive wear. Fatigue wear occurs when a rotating shaft is subjected to reversal of bending stresses. Corrosive wear is due to the reaction of the material surface with the environment or an external agent. [6] Wear occurs in ball and roller bearings due to corrosion, shock loading of fatigue. Atmospheric agents like dirt and girt are the other external factors which are responsible for wear. [4] 3.1.4 Compatibility: Alloys are usually selected as bearing materials. Alloy is a solid composition consisting of two or more metals and elements in fixed proportions. The two alloys which are used to manufacture the bearings are Chrome Steel and Stainless Steel. Steel is an alloy of iron and carbon. [17] Various other elements like silicon, manganese, phosphorous, sulphur, chromium and molybdenum are added in chrome and stainless steels in order to increase the strength, hardness and corrosion resistance of the alloys. [18] Carbon is used in the alloy to form cementite structure and to formation of pearlite, spheroidite, bainite, and iron-carbon martensite. This improves hardenability of the alloys up to 0.65%. Wear resistance is increased up to 1.5%. Toughness of the alloy reduces and the brittleness increases when carbon is added. Manganese increases the hardness penetration of steel. Chromium is added to increase hardness, toughness and wear resistance to steel. Silicon acts as the deoxidiser during the manufacturing process. [19] 3.1.4.1 Chrome Steel Chrome steel is one of the widely used alloys to manufacture bearings. It is used mainly in high load bearing applications as this material is capable of withstanding very high loads. The machinability of the material is as high as highly finished, less noisy bearings are obtained. Also the life of the bearings is also very high. Under test conditions, the Rockwell hardness of the material is observed as 60 64 C. This material is used in applications where corrosion is not considered. [16] The constituent elements in the chrome steel are given in the table 1. 3.1.4.2 Stainless Steel The standard material used for the bearings is 400 series Martensitic Stainless Steel. This type of steel is highly resistant to corrosion and hence stainless steel bearings are used in applications where corrosion is to be taken into account. It is having less load withstanding capacity when compared to chrome steel. There are three types of 400 series Stainless Steel suitable for making bearings. These materials are developed by manufacturers to be used for certain specific applications. [16] 3.1.4.2.1 DR Stainless steel This material is highly resistant to corrosion and is used in applications which deal with highly corrosive medium. The material can be precisely machined so as to obtain high degree of finish to the surface of bearing. This helps in smooth, low noise operation of the bearings. The Rockwell hardness of the material is observed as 58 60 C. [16] The chemical composition of the material is given in table 2. 3.1.4.2.2 AISI 440C Stainless Steel AISI 440C Stainless Steel is highly resistant to corrosion and is easily available. But it is not widely used now a day when more modern materials are developed. The Rockwell hardness of the material is 58-60 C. [16] The chemical composition is given in table 3. 3.1.4.2.3 ES1 Stainless Steel: This material is highly resistant to corrosion and has high machinability. Thus highly finished surfaces can be produced. The material is having a Rockwell hardness number of 58 60 C. [16] The composition of the material is given in table 4. 3.2 SURFACE: Surface quality of the materials is one of the major tribological factors which determine the efficiency of the product. [4] Surface finish decides the amount of friction and wear of the material. Surface texture and conformity are the terms which are to be given importance. 3.2.1 Surface texture: The surface of the material is the part which interacts with the environment. The surface may not be highly finished due to several reasons. It may be due to the imperfections caused during manufacturing, due to external agents or due to loads acting on the surface. The deviations observed on the surface can be mainly classified into three which includes roughness, waviness and error of form. [23] Roughness is the surface irregularities which consist of rises and valleys. This creates an uneven surface pattern. Waviness is the small ups and downs on the surface which is having less amplitude that of roughness. These may be caused due to work piece deflections, vibration or heat treatment. Error of form is the slight deviations from the nominal shape. [6] The surface profiles can be traced by using different apparatus like Abbott profilometer, Tomilson surface finish recorder and Talysurf surface finish recorder. [4] 3.2.2 Conformity: Conformity is the degree of agreement between the surfaces. [5] An interface consisting of two plates is said to have high conformity. Journal bearing is an example for high conformity material. An interface consisting of a plate and a ball is said to be having low conformity. Ball bearing is an example for low conformity material. Conformity is an important factor which is to be considered as it has an important role in determining the pressure, shear stress and temperature in the interface. [5] Figure 7- Surface Texture [23] 3.3 LUBRICANTS: Lubrication is the technique employed to reduce wear by the interposition of a solid, liquid or gas between the two surfaces which come into contact with one another. It was a persistent problem for man for centuries from the day he used to move materials. Friction consumes and wastes energy whereas wear leads to the damage of the equipment which are undesirable and it has to be avoided at any cost. Every moving part of machinery is subjected to friction leading to wear and tear which has to be avoided. Lubrication plays a vital role in avoiding the friction between mating surfaces. The history of lubricant begins thousands of years before. It was found that the ancient Egyptians used lubricants to avoid friction in the wheels of chariots. [24] In ancient times lubricants were of animal, plant and marine origin. Later mineral oils were started to use as lubricant. The new science of lubrication based on hydrodynamics came in 1880s. [24] Lubricants are of solids, liquids and gases but liquid lubricants are widely used. These include mineral oil, synthetic oil, grease, vegetable oil and water. Lubrication is done by applying a thin film of lubricant between the surfaces in contact. [6] Thus undesirable problems like friction, wear, noise and vibrations can be reduced to a very high extent. 3.3.1 Viscosity: Viscosity of a lubricant is the main characteristic which is taken into account before selecting it for a specific application. Friction, heat generation, film thickness and load carrying capacity depend upon the viscosity of lubricant used. Generally viscosity can be stated as the hindrance of the fluid to flow. But based on lubrication, viscosity is the measure of ability of fluid to maintain lubrication at specific operating conditions. [24] 3.3.2 Lubrication Regimes: Lubrication can generally be classified into four different regimes based on the thickness of the fluid film in between the surfaces in contact. They include: Hydrodynamic Lubrication Boundary Lubrication Mixed Lubrication Elastohydrodynamic Lubrication 3.3.2.1 Hydrodynamic Lubrication: image8.jpg Figure 7- Hydrodynamic Lubrication [25] In hydrodynamic lubrication, a fluid film is formed in between the two surfaces in contact. Thus one surface floats on the other and there occurs no direct contact between the surfaces. In microscopic level the surfaces of the materials consist of asperities. In normal condition without lubrication, the asperities are in direct contact with each other. When one surface slides over the other, the asperities get deformed producing friction and hence wear. Hydrodynamic lubrication helps avoid the friction as there is no direct contact between the surfaces. The viscosity of the lubricant helps to increase the fluid pressure in between the surfaces. Thus the lubricant layer holds the surfaces apart. As the lubricant layer formed is thicker than the surface roughness of the material, one material slides over the other without damaging the surface. It is observed that the thickness of the film is more than 1 µm. [24, 25] The surface is separated apart by hydrostatic lift. A fluid flowing over a surface immediately takes the speed of the surface. Similarly when the fluid moves in a converging gap, the pressure increases and the surface is lifted. [25] 3.3.2.2 Boundary Lubrication: Boundary lubrication is a type of lubrication in which the surface roughness of the material is same as that of the fluid layer thickness. Thus when one surface moves upon the other, the asperities comes into contact. When load is applied the asperities gets plastically deformed which leads to friction and wear. As friction is not desirable different methods are also adopted to reduce friction in this type of lubrication. This includes the use of various additives to the lubricants. The additives are classified according to the surface action exhibited on the material surface. They are mainly of three types. Physically absorbed layers Chemically absorbed layers Chemical reaction layers 3.3.2.2.1 Physically adsorbed layers: When the lubricant is applied, it forms a layer on the material surface. The weak intermolecular force called van der Walls force exerted by the layer of the lubricant helps to attach to the surface. This layer lubricates and allows the other surface to slide over the other without causing friction. As the lubricant is not undergoing any chemical reaction, the process is reversible. The bonds formed by van der Walls force are weak and it can be removed. The main disadvantage of the physically adsorbed lubricants is that they have a temperature limit above which the lubricant melts. 3.3.2.2.2 Chemically adsorbed layers: Chemically adsorbed layers are those formed due to the chemical reaction with the surface material. Chemisorption is a type of adsorption in which the molecules are hold tight by the valence force of the molecules of the lubricant. The bonds created are stronger than the physically adsorbed layers. Usually chemically adsorbed lubricants form long chain fatty acid molecules, which has high affinity to metal surfaces. Fatty acid additives like stearic and oleic acid forms chemically adsorbed layers. The typical thickness of the boundary film is about 3 µm. As chemical reaction takes place in the interface, the adsorbed layer can be removed only under extreme conditions like high temperature, vacuum or by using some chemical treatments. [26] 3.3.2.2.3 Chemical reaction layers: Chemical reaction layers are formed by the reaction of additives in the lubricant with the surface of the material on which it is applied. In this adsorption is not taking place, instead a chemical reaction that bonds the lubricant and the material occurs. Thus the layers formed are permanent. The main disadvantage of physisorption and chemisorptions is the temperature limit above which the lubricant gets ineffective. In this type of reaction the working temperature is not a factor. Hence this type of lubrication is used in high speed and high load operating systems as high temperature is developed in these cases. Zinc dialkyl dithiophosphate (ZDDP) is widely used as an additive to produce effective chemical reaction films. [24] 3.3.2.2 Mixed Lubrication: Mixed lubrication has the features of both hydrodynamic lubrication and boundary lubrication. In hydrodynamic lubrication the contact surfaces are separated apart by the pressure of the lubricant interposed between the surfaces. Hence there will not be any contact between the two surfaces in motion. But in boundary lubrication, one surface rests on the other. When the surface moves the asperities gets plastically deformed which causes friction and wear. Mixed lubrication acts between the two extremes of hydrodynamic and boundary lubrication. In mixed lubrication regimes a fluid film layer is developed where contact takes place between the asperities of the surfaces. Thus a slight deformation is formed while sliding occurs which is highly desirable. The film thickness ranges from 0.05 µm to 0.1 µm. [25] 3.3.2.3 Elastohydrodynamic Lubrication: Elastohydrodynamic lubrication is a type of lubrication which brings together hydrodynamic lubrication, hertzian contact and change in viscosity with pressure. In this method of lubrication, the surface is modified to minimise friction. Elastohydrodynamic lubrication is used in applications where low conformity and highly loaded tribological interfaces are present. Roughness of the wearing surface is taken into consideration in this lubrication. Roughness is taken as the average of high and low points of the surface which is called as the centreline average. [27] A non conformal contact can produce pressure to a very high level. When the pressure increases it directly affects the viscosity of the lubricant. In normal conditions the viscosity of the lubricant is less noticeable but during elastohydrodynamic lubrication the viscosity increases which makes the lubricant act as a semi solid. This creates a thin film of oil in between the mating surfaces. [25] 3.4 OPERATING CONDITIONS: Operating conditions are the main aspect to be taken into account while designing a mechanical component including bearings. There are different factors which comprises the operating conditions. Load Relative Motion Temperature Environment 3.4.1 Load: The load applied on each ball and roller is to be determined to manufacture the bearings which can operate at the desired applications without failure. In order to calculate the load deflection relationship is to be developed for roller element contacting raceways. In almost all the applications the outer or inner raceways is in steady state rotation. The speed of the rotation may not be large enough to affect significantly the distribution of the load equally on each roller or ball elements. The rigidly supported bearing is subjected to radial load which may lead to deflection. The radial deflection at any rolling element is given by ÃŽ ´ÃË† = ÃŽ ´r cos ψ  ½ Pd [2] Where ÃŽ ´ÃË† = radial deflection r = ring radial shift ÃŽ ¨ = angular location Pd = diametral clearance Thrust load and roller bearings are also subjected to thrust loads which are distributed equally among the rolling elements. The thrust load can be calculated using Q = Fa / Z Sin ÃŽ ± [2] Where Q = thrust load Fa = applied load Z = number of rollers per row ÃŽ ± = contact angle 3.4.2 Relative Motion: Relative motion is the motion of either one or both surfaces with respect to each other. There are different forms of relative motion depending upon the style of motion. They include sliding, rolling, spinning and bouncing. Sliding refers to the smooth movement over a surface maintaining the contact between each other. Rolling is the movement by revolving within the axis. Spinning is the rotation of a material within its axis. Bouncing is the rebounding due to an impact. Chance for sliding occurs in the rolling bearings due to thrust loads. Bouncing may occur due to sudden fluctuation in loads which may lead to destruction of bearing material. 3.4.3 Temperature: Operating temperature is a factor which is to be taken into consideration for the smooth functioning of the bearings at load conditions. Temperature rise may occur in the bearings during operation which may be due to different reasons. One factor which causes the rise in temperature is the application of excess load. If excess load is applied, the material may not be designed to withstand that much high load. So it may lead to failure. Another reason for the temperature rise is the absence of lubricant. The lubricant should be interposed to the surfaces in contact. If it fails to continuously supply the lubricant to the surface, friction is produced which results in gradual rise in temperature. Various coatings are also used to overcome temperature extremes. 3.4.4 Environment: Nature of environment is the feature which can influence the efficiency and life of the bearings. There are different agents which affect the operating conditions of the bearings which may be harmful. These include contaminations like dust, wear particles, air, water, process fluid etc. Insulations are to be provided to avoid exposure to these external agents. This can be done by using seals or coatings. 4. CONCLUSION: The various tribological factors are to be considered while designing rolling bearings. This tribological audit looks for the different factors which affect the performance and life of the bearings. The major tribological factors found include material, surface, lubrication and operating conditions. Different solutions are available which can be applied to each factor to lower the friction. Material should be wisely selected which can be easily machined to obtain highly finished surfaces and should possess the strength to withstand the loads applying on it. The material should be selected according to the application. Surface texture and conformity of the material is to be carefully observed as the surface finish is one of the major factors which cause friction. Lubrication plays a major role in the performance of the equipment. Right method of lubrication is selected. Elastohydrodynamic lubrication forms the film with minimum thickness which is the most desirable in bearings. Operat ing conditions affects the performance and life of the bearings which includes contaminations like dirt, wear particles, water, corrosive process fluid etc. Proper measures are to be taken to avoid exposure to these agents. From this audit it is clear that we have to take care of the tribological factors and select the most suitable ones to obtain maximum performance and life to the rolling bearings.

Funerals of Kings Essays -- Literary Analysis, Beowulf

Beowulf starts with the death of Shield a great king in the eyes of the Geats, it also ends with the death of Beowulf. These funerals are similar in many ways. These funerals can be a reflection of the lives these kings lived because each king had his own way he wanted to be remembered. These funerals both involve huge amounts of treasures being loaded on to ships or back in to the ground and how the Geat people mourned for the loss of the kings.†¨ Treasures were used to gain loyalty from other men in Geat â€Å"steadfast companions will stand by him† (Beowulf 23). Theses â€Å"steadfast companions† (Beowulf 23) help the king survive and help conquer lands and allowing a king to stay in power. In the end of this poem even those gifts will not get the support Beowulf needs. The treasure that was laid on the boat for Shield was â€Å"Far-fetched treasures / were piled upon him, and precious gear† (Beowulf 36-37) A â€Å"far-fetched treasure† (Beow ulf 36) would be some of the rarest in the world. Shield has told his men to â€Å"Shoulder him out to sea’s flood† (Beowulf 30) The boat they put him in was â€Å"A ring-whorled prow rode in the harbor, / ice-clad, outbound, a craft for a prince†(Beowulf 32-33). The description of the boat I think shows the honor that the Geat’s wanted to show their kings and how ornate they make things. At Beowulf’s funeral at the end of the poem they build a great pyre â€Å"The Geat people built a pyre for Beowulf, / stacked and decked it until it stood foursquare.†(Beowulf 3137-38). The pyre is like the boat in the first funeral the boat is built ornately and to stand the test of time. The pyre is built to be tall and strong very similar to the boat. â€Å"hung with helmets, heavy war-shields / and shining armor, just as he had ... ...going or where the â€Å"to wind and tide, bewailing him† (Beowulf 49). They built a memorial on the high grounds letting all that can see know that a great king laid there. All the treasure that had been found in the cave where the dragon had stayed was put back in to the ground where the memorial is. â€Å"They let the ground keep that ancestral treasure / gold under gravel,† (Beowulf 3166-67). These treasures had been around for ages and ages, gold is taken from the ground and in the end put back in to the ground. These kings have thought about how they wanted to be remembered by the people of the time. Their funerals reflected back on their lives, through the gold that was laid on to Shields ship and that was put in the memorial on the coast for Beowulf. Works Cited Greenblatt, Stephen. The Norton Anthology Of English Literature. 8th. A. W W Norton & Co Inc, 2006.