Analysis Of Rayleigh Step Bearings Biology Essay

Analysis Of Rayleigh Step Bearings Biology Essay According to importance and application of slider bearings in industries, investigation and analysis of this type of bearings are significant and inevitable issue. A widely used bearing type is the slider bearings with application in many cases such as different types of engines, compressors, turbines, electric motors and electric generators. To ensure that no contact occurs between the opposing surfaces, the dimensions of the bearing surface are chosen, such that a lubricant film of sufficient thickness is available under all operating conditions. The classical theory of hydrodynamic lubrication assumes that the inertia forces in the fluid film are negligible. For large bearings using low kinematic viscosity lubricant or for high speed, the inertia forces could be important. So the inertia terms should be entered in the calculations. This increases the accuracy of obtained responses and closes them to reliable results. Rayleigh bearing is designed in 1918 by Lord Rayleigh. He was first person who considered the concept of optimization design in lubrication applications and obtained an optimum design for an infinite-length stepped bearing by the use of a variation technique (Lord Rayleigh, 1918). Since then, there have been some studies on the characteristics of step bearings. Dowson (1962) introduced the generalized Reynolds equation, which allows for cross-film temperature variations. Then, this equation solved with realistic THD boundary conditions by Ezzat and Rohde (1973) using the finite difference method. Boncompain, et al. (1986) improved the numerical model by considering reverse flow, fluid-film rupture and elastic deformations (THD solution). Auloge et al. (1983) studied the optimum design of Rayleigh step bearing and determined the relationships between step location and height along with non-Newtonian lubricants. The same method was used by Fillon and Khonsari (1996) in tracing design c harts for tilting-pad journal bearings. Jianming and Gaobing (1989) have presented the optimum design of one-dimensional Rayleigh step bearing with non-Newtonian lubricants. Tello (2003) has theoretically studied the regularity of the solution to the Reynolds equation in Rayleigh step type bearings for both compressible and incompressible fluids by employing a rigorous mathematical approach. Besides, there are many research works in which the well known Reynolds equation was solved by different numerical schemes in predicting the lubricant pressure field in step bearings (Hideki, 2005; Dobrica and Fillon, 2005). Rahmani et al. (2009) comprehensively studied the Rayleigh step slider bearing including the effect of variations of pressure at the boundaries on the optimum parameters. The bearing is also optimized considering the lubricant flow rate, friction force and friction coefficient. In all of the above studies, the Reynolds equation was solve as the governing equation for calculation of lubricant pressure distribution in bearing lubricant flow. This equation is a simplified form of the momentum equation by neglection of fluid inertia terms. It is clear that under the condition of low lubricant viscosity and high runner surface velocity, this equation may lead to unreliable results. In the present study which a numeric one, the two-dimensional Navier-Stokes and energy equations are solved by CFD method with considering the variation of lubricant viscosity with temperature. By this technique the THD characteristics of Rayleigh slider bearings running under different steady conditions are explored. 2. PROBLEM DESCRIPTION The schematic and coordinate system of Rayleigh slider bearing is shown in Fig. 1. The bottom wall of the step bearing moves with constant velocity U (runner velocity). The sudden change in film thickness generates a hydrodynamic pressure field that supports an applied load W. At the inlet section, the oil film is entered at 40oC with combination of Poiseuille and Couette flows. The total length of the bearing is and the film thicknesses before and after the step location are and , respectively. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSgeometryasli.wmf Fig. 1: Sketch of problem geometry Two important geometrical factors in step bearings are (1) (2) In these explanations, and represents the bearing length ratio and the bearing height ratio, respectively, which are two important bearing geometrical factors. 3. THEORY 3.1. Governing equations For lubricant flow in bearings, the governing equations which are written for a two-dimensional, steady, incompressible, laminar and variable viscosity flow consist of the continuity, Navier-Stokes and energy equations. These equations in non-dimensional forms can be written as: (3) (4) (5) (6) Where and represent the dimensionless viscous source terms: (7) (8) And is the dimensionless viscous dissipation term: (9) Also the dimensionless oil viscosity based on Vogel equation can be calculated as follows: (10) In this expression, is the temperature-viscosity coefficient of the lubricant. The value of can is determined using two given viscosity values at and as follows (Khonsari and Booser, 2008): (11) In equations 3 to 9, the following non-dimensional groups are used: (12) In these definitions, is the thermal diffusivity of the lubricant and is the inlet lubricant viscosity. The main physical quantities of interest in lubrication study are the load capacity and friction force that can be computed using the lubricant velocity and temperature fields. The load capacity of the step bearing per unit width is obtained by further integration of lubricant pressure distribution on the runner surface as follows: (13) The friction force of the step bearing per unit width is calculated by the shear stress on the bottom wall as follows: (14) Where: (15) 3.2. Boundary conditions The entire domain is fully flooded, such that oil pressure at the inlet and outlet sections of the bearing is set to zero atmospheric gauge pressure. Also the no-slip condition is employed on all boundary solid walls. At the inlet section, oil enters into bearing with uniform temperature of and a specified velocity distribution which is a combination of the poiseulle and cuette flows whose pressure gradient is determined by numerical solution of the Reynolds equation. At the outlet section, zero axial gradients for all dependent variables are employed. Finally, the adiabatic condition is imposed on all of the bearing solid surfaces. 4. SOLUTION PROCEDURE Finite difference forms of the continuity, momentum and energy equations were obtained by integrating over an elemental cell volume with staggered control volumes for the x- and y- velocity components. Other variables of interest were computed at the grid nodes. The nondimensionalized governing equations were discretized by using the hybrid scheme and numerically solved by the SIMPLE algorithm of Patankar and Spalding (Patankar and Spalding, 1972). Numerical solutions were obtained iteratively by the line-by-line method progressing in axial direction. The iterations were terminated when the sum of the absolute residuals was less than for each equation. Numerical calculations were performed by writing a computer program in FORTRAN. mesh asli11 Fig. 2: A schematic of grid generation As shown in figure 2, the computational domain is divided into three blocks, each having Nx points in x-direction and Ny points in y-direction. The mesh is non-uniform in x- and y- directions, because the grid refinement around the step is necessary to capture the occurrence of the recirculation and other flow changes due to the sudden change in geometry. As the result of grid tests for obtaining the grid-independent solutions, an optimum grid is determined in grid study. Five different numbers of grid size inside the total rectangular computational domain including the blocked-off region with their related numerical results are listed in Table 1. According to this grid study, an optimum grid of 640120 is used in all of the subsequent test cases. Table 1: Grid independent study, Grid size Bearing friction force (KN/m) Bearing load capacity (KN/m) 45080 0.231 16.45 540110 0.217 17.17 590110 0.231 17.48 640120 0.239 17.51 680140 0.241 17.52 5. VALIDATION OF NUMERICAL RESULTS To test the validity of the present numerical results, computations were carried out for a test case and the computed results were compared with the theoretical findings by other investigators. The lubricant pressure distribution on the bottom wall and the temperature distribution on the top wall of the Hideki bearing (Hideki, 2005) are shown in Figs. 3 and 4, respectively. D:payanameThermohydrodynamic with subroutin.mesh moteghayervalidation with Ogata(temprature)Plot validation with OgataCJS.wmf Fig. 3: Lubricant pressure distribution on the bottom wall of the Hideki bearing (Hideki, 2005), The generated hydrodynamic pressure by the sudden contraction in flow domain is clearly seen in Fig. 3, such that at the entrance of narrow gap of the bearing, the maximum lubricant pressure occurs, and at the inlet and outlet sections, lubricant flow in at atmospheric pressure (zero gauge pressure). D:payanameThermohydrodynamic with subroutin.mesh moteghayervalidation with Ogata(temprature)Plot validation with OgataCJS temp.wmf Fig. 4: Temperature distribution on the top wall of the Hideki bearing (Hideki, 2005), Fig. 4 shows that the lubricant temperature increases along the flow direction because of the viscous dissipation in both domains upstream and downstream of the step. Such that, the rate of temperature increase in upstream region to the step is very greater than that is in downstream domain. It is due to this fact that the viscous dissipation in lubricant flow with small film thickness is high in comparison to lubricant flow with large film thickness. However, good consistencies are observed between the present numerical results with theoretical findings by Hideki (Hideki, 2005) about computations of both lubricant pressure and temperature distributions. 6. RESULT AND DISCUSSION In this research work, the THD characteristics of Rayleigh step bearings are obtained by numerical solution of the Navier-Stocks and energy equations using the CFD technique. An attempt is made for obtaining the effects of important parameters including the runner surface velocity, bearing length ratio and bearing height ratio on thermal and hydrodynamic behaviors of Rayleigh step bearings. All of the subsequent figures are about a Rayleigh step bearing whose properties and geometrical parameters are given in Table 2. Table 2: Bearing parameters and lubricant properties Parameters Units Values in present work b m 0.08-0.12 h1  µm 480 U m/s 10-30 Tin 40 Ï  860 Cp 2000 Kf 0.13  µ at 40 C 0.03  µ at 100 C 0.0045 0.28-0.98 1.2-2.5 First the oil flow pattern inside the bearing is shown in figure 5 by plotting the fluid velocity vectors. The adverse pressure gradient in the upstream flow domain before the step location which leads to hydrodynamic pressure generation causes a concave shape for velocity distribution. Such that the velocity distribution changes to convex shape after the step where there is a favorable pressure gradient. Behind the step surface near to the stationary wall, a circulated flow domain happens which is due to the effects of both viscous friction and positive pressure gradient in this region. As another result that can be seen from Fig. 5, one can notice to almost stationary flow region in block 1 (see Fig. 2). Therefore, the lubricant average velocity across blocks 2 and 3 remains approximately constant. C:UserszahraDesktopUntitled.png Fig. 5: Velocity vectors in step bearing lubricant flow, In Fig. 6, the lubricant pressure distributions along the bottom wall at five different values for the runner surface velocity are shown. It is seen that the velocity of moving surface has considerable effect on the value of generate hydrodynamic lubricant pressure, such that oil pressure has an increase trend by increase in velocity under a unique pattern. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of PKcompare of speed runner.pkspeed runner.wmf Fig. 6: Effect of runner surface velocity on lubricant pressure distribution along the bottom wall, A similar study is done for investigating the effect of runner velocity on thermal behaviour of step bearing in Fig. 7. It is seen in this figure that bearings with high runner surface velocity operate under high temperature condition. Besides, it is depicted in Fig. 7 that in both domains before and after the step, lubricant temperature increases along the flow direction because of the viscous dissipation. Also, it is seen that the oil temperature at the outlet section is affected strongly by the runner velocity, such that the bearings with high velocity have high temperature lubricant flow at their outlet sections. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of TPcompare speed of runner.TpTshaftTshaft.wmf Fig. 7: Effect of runner surface velocity on lubricant temperature distribution along the bottom wall, D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of PKcompare of epsilonepsilon.wmf Fig. 8: Effect of bearing length ratio on lubricant pressure distribution along the runner surface, The lubricant pressure distributions along the runner surface at four different values of the bearing length ratios are illustrated in Fig. 8. It is evident that the location of maximum pressure moves toward the downstream side by increasing in bearing length ratio, because the step location moves toward this sense when increases. Besides, it can be found from Fig. 8 that there is an optimum value for bearing length ratio to obtain the most value for lubricant maximum hydrodynamic pressure. It is depicted in Fig. 8 that this value for bearing length ratio in this test case is. Therefore, is an important parameter in step bearings that has great effects on lubricant pressure and consequently in bearing load capacity. The effect of bearing length ratio of thermal behavior of step bearing is studied in Fig. 9 by plotting the lubricant temperature distributions on the runner surface for bearings with different length ratios. This figure shows that the effect of on temperature distribution is less than its effect of the hydrodynamic lubricant pressure. However, this figure depicts that bearings with length ratio greater that run cooler than the bearings with small less than. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of TPcompare of epsilonCompare Tshaft of epsilonTshaft.wmf Fig. 9: Effect of bearing length ration on lubricant temperature distribution along the runner surface, The variations of lubricant maximum pressure and temperature with bearing length ratio are presented in Fig. 10. This figure reveals the same trends for THD characteristics of step bearing those have been shown in the previous figures. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Epsilon moteghayer(W.F.eta.etam)compare of ep.P.T.wmf Fig. 10: Variations of lubricant maximum pressure and lubricant maximum temperature with bearing length ratio, In order to study more about the effect of bearing length ratio on THD characteristics of step bearings, the variations of bearing load capacity and friction force with are plotted in Fig. 11. This figure presents that there is a maximum value for load capacity that takes place at =0.718. Besides, it is revealed from Fig. 11 that in bearings with high length ratio, low friction force exists in comparison to bearings with small values for . D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Epsilon moteghayer(W.F.eta.etam)compare of ep.w.f.wmf Fig. 11: Variations of load capacity and friction force with bearing length ratio, Similar study is also done for investigating the effect of bearing height ratio on THD characteristics of step bearings by plotting the lubricant pressure and temperature distributions and also the variations of load capacity and friction force with various values of the parameter . According to Figs. 12 and 13, it is revealed that the values of lubricant pressure and temperature increase by increasing in bearing height ratio. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of PKcompare of ksiksi.wmf Fig. 12: Effect of bearing height ratio on lubricant pressure distribution along the runner surface, D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of TPcompare of ksiCompare Tshaft of kesiTshaft.wmf Fig. 13: Effect of bearing height ration on lubricant temperature distribution along the runner surface, This behavior is also presented by Fig. 14 in which the variations of maximum lubricant pressure and temperature are plotted with bearing height ratio. It is seen that both and have increasing trends with increase in the value of , such that the rate of increase in maximum temperature is greater than that is in maximum pressure. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Kesi moteghayer(W.F.eta.etam)compare of ksi.P.T.wmf Fig. 14: Variations of lubricant maximum pressure and lubricant maximum temperature with bearing height ratio, Fig. 15 shows a similar trend for bearing load capacity and friction force with the variation of height ratio. Such that it is seen in this figure that both load capacity and friction force increase with increasing in bearing height ratio. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Kesi moteghayer(W.F.eta.etam)compare of ksi.W.F.wmf Fig. 15: Variations of load capacity and friction force with bearing height ratio, In the following figures, an attempt is made to verify the influences of bearing length, b, on the THD characteristics of step bearings. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTScompare of PKcompare of length bearingcpmpare b.wmf Fig. 16: Effect of bearing length on lubricant pressure distribution along the bottom wall, D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Lenght moteghayer(W.F.eta.etam)TshaftTshaft.wmf Fig. 17: Effect of bearing length on lubricant temperature distribution along the bottom wall, It is seen from Figs. 16 to 19 that in long bearings, the values of lubricant pressure and temperature and consequently the amounts of maximum pressure and temperature are high that leads to have high bearing load capacity and bearing friction force. D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Lenght moteghayer(W.F.eta.etam)compare of length.p,T.without point.wmf Fig. 18: Variations of lubricant maximum pressure and lubricant maximum temperature with bearing length, D:payanameThermohydrodynamic with subroutin.mesh moteghayerPLOTSplot Lenght moteghayer(W.F.eta.etam)compare of length.w,f.without point.wmf Fig. 19: Variations of load capacity and friction force with bearing length, 7. CONCLUSION This paper deals a numerical study for investigating the THD characteristics of Rayleigh step bearings running under different steady conditions. The set of governing equations consisting of the Navier-Stokes and energy equations is solved by the CFD technique and the variation of lubricant viscosity with temperature is also considered into account. This mathematical model and numerical method lead to more accurate numerical results in comparison to those obtained before by other investigation with numerical solution of the Reynolds equation that neglects the fluid inertia terms. It is found that the thermal and hydrodynamic behaviors of step bearing are affected considerably by the runner surface velocity and the bearing geometrical factors. Nomenclature B bearing length dimensionless velocity components upstream bearing length load capacity of bearing downstream bearing length horizontal and vertical coordinates Cp heat capacity dimensionless coordinates friction force of bearing upstream film thickness Greek symbols downstream film thickness friction coefficient step height modified friction coefficient Kf thermal conductivity dynamic viscosity width of bearing dimensionless dynamic viscosity origin of coordinate  µ1 dynamic viscosity at pressure  µ2 dynamic viscosity at pressure at the inlet kinematic viscosity pressure at the outlet density dimensionless pressure shear stress Pr Prandtl number Pe Peclet number Subscripts Re Reynolds number fluid Temperature inlet Tin inlet temperature maximum dimensionless temperature surface runner velocity velocity components

Shakespeares Macbeth as a Tragic Hero Essay -- Macbeth essays

Macbeth as a Tragic Hero According to the Greek philosopher Aristotle, "The best tragic plot moves the hero from prosperity to misfortune, occasioned not by depravity, but by some great mistake he makes. The plot of Macbeth follows these basic guidelines; throughout the play we follow the path of the main character as his life is torn apart as a result of the colossal mistake he makes when he kills Duncan. It is for this and the many ensuing reasons that we can say that Macbeth accurately portrays the image of a tragic hero as outlined by Aristotle. Aristotle's first guideline for an effective tragic hero is someone that is basically good. While Macbeth does not exactly make sound moral decisions, toward the beginning of the play his conscience is fighting against his greed, and this demonstrates that he does have a basic level of goodness, although towards the end it is difficult to find it. For example, Macbeth says, "We will proceed no further in this business; he hath honored me of late, and I have bought golden opinions from all sorts of people..." This seems to be his conscience speaking out against the proposed killing of Duncan. It is, however, a very feeble protest, but this is probably due more to the passive tendencies he harbored before the first killing than to a lack of inner goodness. Macbeth was probably a good man in the beginning, but because he is easily influenced and as a result of his inability to make good decisions, it is easy to lose sight of that basic goodness that is undoubtedly in him. Aristotle also states that a hero should be lifelike. Although he never states exactly what he means, it is usually interpreted to mean that a tragic hero should seem like a real human b... ...whole mess in the beginning- in battle. In conclusion, these numerous different factors lead me to say that Macbeth can accurately be called a 'tragic hero'. Even at the most basic level of tragedy it is true, because there is a definite feeling of pity for him. Despite the fact that he ruthlessly murdered numerous prominent individuals, including his own king, there is still a sense of pity. While the audience ultimately feels relieved that Macbeth is justly punished at the expense of his own life, there is the feeling that he was really just a good guy who made some bad choices and got pulled into something way over his head. For this reason we sympathize with him, and out of the realization that this situation could quite possibly happen to any of us, fear and pity him as well. All these factors combined prove that Macbeth really is a tragic hero.

Achilles, Aeneas, and Roland

Imagine living in a turbulent world, where people lived their day to day lives praying that they would see the next sunrise. That was life for villagers that lived during the times of the ancient Greeks and Romans, as well as during the medieval period when Germanic tribes ruled Europe. To help them get through their very insecure days, people would tell oral stories of great heroes, like those of Achilles, Aeneas, and Roland. Achilles was a Greek war hero who fights in the Trojan War, a ten year long war between Greece and Troy (present day Turkey). Aeneas was an epic hero in ancient Roman folklore. He was a soldier who fought in the Trojan War and after surviving the destruction of Troy, he later founded the city of Rome. Roland was an epic hero of the Franks, a Germanic tribe in present day France. All three of these heroes played vital roles in giving strength and hope to the peoples of their respective cultures. The Illiad was an epic written by a Greek poet named Homer. It takes place in the last days of the Trojan War. Achilles was an integral part of the war. He helped raise the Greek soldiers’ moral, he was an excellent fighter and swordsmen, and he killed Hector, who was the leader of the Trojan forces and son of the King of Troy. It is said that Achilles was half man and half god. He is the offspring of Peleus, King of Thessaly, and the sea nymph Thetis, who had dipped her infant son in the river Styx, thus making him invulnerable except for the hell by which she held him. In the epic, Homer gave Achilles many human characteristics, including revenge, anger, and love. He even gave him many challenges to overcome. In the beginning of the war, he did not fight because of an affront to his honor that angered him. However struck with grief when his dearest friend Patroclus is killed by Hector, he in revenge joins the war. Throughout the Illiad, this male protagonist is on a quest to reconcile selfhood and communal responsibility. After killing Hector, Achilles shows his humanity by sparing Priam, the King of Troy, when he sneaks in to the Greek camp. He even grants the kings request by giving back his dead son’s body, so that he can have a proper burial. He could have killed Priam and ended the ten year long war, however he chose to act on good virtue and morals and that showed his humanity. Aeneas, the Trojan born epic hero in Virgil’s Aeneid, was Rome’s mythical founder. His father was Prince Anchiseses, who was the second cousin of the King of Troy, King Priam. His mother was Venus, the god of love, beauty, and procreation. Like Achilles, Aeneas was also part god, part man. His mission was to gather any survivors from Troy and take them on a journey to Italy, where he will establish the city of Rome. On his journey however they end up settling in Carthage where he meets and has a long affair with the beautiful Carthaginian princess, Dido. While in Carthage, the messenger god, Mercury, leaves Aeneas a message. The message was to remind him to leave Carthage and proceed to Italy and end his love affair with princess Dido. Despite the fact that he loved Dido very much, his Stoic sense of duty overcomes his desire for personal fulfillment. That is the characteristic of a true hero. He told Dido that he never asked for any of what happened. He said if he had his way, he would be watching over the city of Troy, and caring for his people. Also, Priam’s palace would still be standing. The last thing he tells her was that he goes to Italy not because he wanted to. He was asked by the God’s to move to Italy and he will not fail the duties that are installed for him. That is what makes him a pious man. Roland, the last of the greatest epic heroes, was the nephew of Charlemagne, a Frankish chieftain who was crowned by the pope as â€Å"Emperor of the Romans. † In The Song of Roland, Roland was described as a very modest yet arrogant man. He said that he could strike great blows to the pagans with his sword, Durandel. In the story, he faced the challenge of halting the Muslim invasion of France. The Saracens were the Muslims invading France. He was described as a model medieval hero, because he was a natural Christian leader who was sent on a holy war to stop the Muslims from invading and converting France. He was a noble Frenchman, who died at the hand of power and land hungry, Islamic forces. At the end of the story, it is said that he died while he was chasing away the pagans. To this day, in the 21st century, homo sapiens still write stories about heroes that will save them and society. The number one characteristic that describes a hero is one that has a Stoic sense of duty that can overcome the desire for personal fulfillment. Achilles, Aeneas, and Roland were all created to create personal comfort for their people that lived in such a hectic and dangerous world. These three protagonists who were viewed by their cultures as gods also showed their people that they did portray human characterists (two out of the three even die) and that anyone can be like them if they tried. In a way they were used to inspire their respective residents to be better civilians in their community. If everyone could follow that, than living in a turbulent world would go from reality to fiction.

Japanese Culture and Literature Essay

The Japanese technology is leading the world these days. Especially with the mobile phone market is Japan far ahead of Europe and the United States. Although these progressions and innovations, two cliches still rule the thinking about the country. One is the fact that Japan is a small country, with no ethnic diversity, and has a high income per head. The other one is that Japan ‘imitates’; the idea that Japan does not make its own products, but tries to improve other products. Japan has of course its own creativity and its own cultural achievements, known throughout the world, such as the ‘tea ceremony’, ‘sumo wrestling’ and ‘sushi’. Japan’s economy, culture and civilization changed rapidly when the cultivation of rice was introduced, from China, in the fourth century BC. The nomadic life they used to live was changed for an agricultural one. They started to settle in villages and a new sense of economy and cooperation was established. This new sense of economic thinking also brought forth an ideal that still holds in the Japanese culture: the need of the group is more important than the need of the individual. The Japanese civilization developed very late in comparison with the civilizations found in Egypt, Greece, India or China. Japan, as consisting completely of small islands, stayed a long time being isolated from the rest of the world and therefore stayed a long time being a hunters-gatherers society. China had a great impact on the development of Japan. In the seventh and eighth century, China represented the most developed country in the world in those days. Before this Chinese influence that changed the political system in Japan, the political system consisted mainly of powerful warlords. These warlords and wealthy families established many different centers and Japan was not a unity. Finally one family succeeded in taking the power over the southern and central islands. This clan and its ‘emperor’ started the imperial line. After this establishment, many Chinese political models were introduced in Japan. Taxation systems, new law codes and the whole political administrative system were copied. This Chinese model did not seem to be the best for Japan. Land was divided among the population equally and the taxes were also equal for all the people. The emperor was the ruler and had absolute power and the administrators were chosen through examination and ability. In Japan, the emperors ruled with the family and kinship ties. There were no examinations or ability tests in the old Japan. The nobility did not want to leave their positions and government and laws started changing constantly. The introduction of Buddhism had a big impact on the Japanese society. The original Shinto religion was completed with Chinese and Korean Buddhism. Apparently, these two religions can co-exist well together. Buddhism can be seen as a ‘nature’ religion and because the people of Japan lived close to nature, this worked out fine. Shinto gave the people no hope beyond death, Buddhism did. Nature is not consistent, it is impermanent, and it keeps on changing and so does live. This concept of impermanence is not only seen in the culture and religion of Japan, but also in literature. Literary themes like suffering, life struggles, awareness of the transient nature of earthly things, is represented everywhere. Japanese Culture and Literature The Manyoshu The Manyoshu is the oldest collection of Japanese poetry. The title means â€Å"collection of ten thousand leaves†. The translation of the Japanese symbol ‘leave’ can also be translated as ‘age’ or ‘generation’. Therefore the collection is sometimes said to be the â€Å"collection for ten thousand ages†, which can be interpreted as a collection for the generations to come. At the time of the last dated poem, 759 AD, Japan had just changed into a society with a governing emperor, a new national identity and government and a new religious system. All these new influences came from neighboring country China, which had a big impact of the development of Japan economically, politically, religious and socially. Contacts with China also brought roads, irrigations works, harbors, new fabrics and pagodas to Japan. Japan was not just coping the Chinese ways, they made their own. This also meant the introduction of a new writing style, coming from the Chinese characters, but with a Japanese twist. It is amazing to see that the quality of the poems of the Manyoshu is very high. The experience and finesse of the writers is special for this collection and hard to find again in the poetry written in later ages. The passion, sincerity and innocence are attracting many people to reading the poems. There are basically two principal written forms used in the poems. The first one is the ‘choka’. This is a long poem with an indeterminate number of lines of alternating five and seven-syllable lines, ending with two seven-syllable phrases. It then has the pattern: 5-7-5, 7-5, 7-5, 7-5, †¦ , 7-7. The second poem form is the ‘tanka’, a short poem, written with a total of 31 syllables in the pattern 5-7-5, 7-7. The Manyoshu is often said to offer everything to the reader because there is so much variety to be found. For some it is also proof of the Japanese identity with its great creativity and complexity. References Keene, Donald. (Ed. ). (1994). Anthology of Japanese Literature: From the Earliest Era to the Mid-Nineteenth Century. New York: Grove Press.

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Miranda v. Arizona essays The landmark Miranda v Arizona decision was rooted in the case of Ernesto Miranda. On March 13, 1963, a bank worker in Phoenix, Arizona was robbed of $8.00. Police suspected and arrested Ernesto Miranda for the theft. By this arrest, Miranda already had an extensive arrest record, including robbery, burglary, assault and attempted rape and a separate During the two hour questioning, Miranda was not offered a lawyer. During the interrogation, Miranda confessed to the theft of the $8.00. In addition, he also confessed to the kidnapping and the rape of an 18-year- old woman 11 days earlier. This confession was the most important piece of evidence that eventually led to Miranda's conviction for rape. He was Miranda's lawyers appealed the conviction for rape, arguing that Miranda did not understand how the Constitution's Fifth Amendment protected him from self-incrimination. The appeal was unsuccessful at the Arizona Supreme Court and was then heard at the United States Supreme Court. After hearing the arguments, the high court reversed the Arizona court's decision. Ernesto Miranda was granted a new trial, where his confession Despite the lack of a confession, however, Miranda was again convicted of rape and kidnapping on the basis of other evidence. After serving 11 years in jail, Miranda was released on parole in 1972. In 1976, Miranda was fatally stabbed during a fight. In an ironic twist, the suspect in Miranda's murder was read his "Miranda" rights and chose to exercise his The landmark Supreme Court ruling is one of Chief Justice Earl Warren's most famous decisions. In ruling for the defendant, the Warren court held that defendants who were engaged in a "custodial interrogation" like Miranda must be informed of their Fifth Amendment before being ...

Land Grabbing in Africa Essay Example | Topics and Well Written Essays - 1250 words

Land Grabbing in Africa - Essay Example Land grabbing in East Africa causes imbalance between the efforts to build sustainable systems that comprehensively try to resolve land-related tensions and interests, as well as pursuits to economic development (Palmer, 2012). Due to this, Heads of States of Africa and Governments have adopted Framework and Guidelines on Land Policy in East Africa. This is to inspire and prompt countries to develop land policies that take into account their particular needs. The presence of continental framework and guidelines and normative instruments like the 11 principles laid out on the Right to Food by the UN Special Rapporteur ensure economic development without weakening the development of any population group. The World Bank plays a greater role in the land grabbing in East Africa. It refers to the land grabbing as agro-investment and makes room for it by creating seven voluntary principles to make the practice of agro-investment responsible. All the seven principles are supposed to safeguard the East Africa’s land from being grabbed. However, this is just a mirage, for these principles are not adhered to, they are just there as beautifying statements. This, therefore, makes the transactions regarding land negative for both the buyer of the land and the seller. Wealthy States are the main causes of the increase in rural poverty that drives many people off the land that they have for generations farmed (Pearce, 2012). For example, there are major environmental and agricultural damage along River Niger caused by the International Land Coalition. This is a global network of civil society and farmers’ organization. Forestry and small scale farming that protects food, unique wildlife and heritage is slowly being converted to wastelands that only profit agribusinesses. Multinational companies in a greater number that vastly exceed the usage by the local communities are using natural resources. As a result, the land’s

Computer networking and management Essay Example | Topics and Well Written Essays - 6500 words

Computer networking and management - Essay Example The protocol constitutes two layers; one is the TLS Record Protocol and the other is TLS handshake protocol. Netgear (2005) further discusses that TLS Record Protocol is a layered protocol. There are different contents for messages at every layer; messages may contain fields for length or details about the message. Record Protocol performs a series of functions; takes the data/message which is desired to be transmitted to the other end, divides the data into smaller blocks, performs the compression function on the data if needed, applies a MAC and encrypts the message according to it and then finally transmits the result. The data which is received at the target server is decrypted, then verified if it has come from the expected host, decompressed and finally passed onto the target host. TLS Record has two main properties, which are discussed below: Connection between the two communicating entities is private. The technique that is used for data encryption is symmetric cryptography. The connection is secure because the key for this symmetric cryptography is unique for every connection, which is communicated between the two connecting applications by another protocol- TLS Handshake Protocol. If security of the connection can be compromised then it is possible to utilize the Record Protocol without encryption. Another characteristic about the protocol is that it provides a reliable connection; this is possible due to the provision of a message integrity check which works on a keyed MAC. The security of MAC is ensured by computing it with a secure hash functions. TLS Handshake Protocol gives a medium for the client and server to authenticate each other and to decide an encryption algorithm. Cryptographic keys are also negotiated among the two applications before any data is transferred or received by either. The steps for TLS handshake protocol are defined in the figure below; The negotiation process of the encryption algorithm is also secure therefore