Journal 6-LEED Assignment Example | Topics and Well Written Essays - 500 words

Journal 6-LEED - Assignment Example he LEED technology, being a globally recognized and widely adopted system was being adapted to in relation to the aspects of green building such as designing, construction, maintenance and operations. The most outstanding factor that is recognized by the article is the fast growing recognition by the global community of the imperative measures that can be used to combat the global menace of climate change. According to the USGBC President and CEO, Rick Fedrizzi, the most appropriate way by which climate change can be countered is through the use of LEED technology in the design and construction of buildings. He applauds the success already attained by LEED global in various spheres and notes that the growing recognition of the same will turn to be more beneficial to human beings, in terms of preserving health, besides helping in saving operational costs. Subsequently, the LEED system is considered to have the potential of providing amicable solutions to the global warming problem that has been coupled by rising sea levels above the normal limits. Rick appreciates that nearly 140 countries in the world have already embraced the aspect of participating in the global certification program of LEED certification. This takes into consideration the fact that nearly 59,000 building projects currently being undertaken globally are being implemented under LEED program. Subsequently, in ranking the countries, the top ten identified in descending order are Canada, China, India, South Korea, Taiwan, Germany, Brazil, Singapore, United Arab Emirates and Finally Finland. The ranking is based on three aspects: total GSM of LEED certified and registered space, GSM of LEED certified space and the total number of LEED projects that have been certified and registered. Canada, for instance, was ranked first for having 17.74 million GSM LEED space and a total of 4,068 projects certified and registered under LEED. Its key undergoing projects such as 100 Street Wellington Street West

Issues of drugs use in public schools Research Paper

Issues of drugs use in public schools - Research Paper Example The second sub-question is the rules and regulation that might be needed to guide the processing of identifying drug users among teachers and students. The other sub-question is how the effectiveness of a drug identificationtechnique chosen could be improved. Analysis in this researchis based on these sub-questions. The research concludes that none of the drug identification techniques is sufficient; it therefore recommends use of other drug identification techniques before deciding to undertake drug testing among teachers and students in public schools. CHAPTER 1: Introduction Context of the problem Drug use in public schools has been identified as a key issue affecting education in this country. Principals and other education administrators have found students in their schools using or in possession of illegal drugs like marijuana (Samaha, 2012). Moreover, there are teachers and other school employees who have been foundusing drugs by the school administrators while in their line o f duty. Therefore, the issue of drug use is a problem that affects the whole public schools fraternity. In the past, students were tested for drug use only when participating in athletics or when undertaking major co-curricular activities (Dempsey, 2011). This proved to be ineffective since the majority of drug users turned to be the idle students who did not engage in any form of sports or co-curricular activities. Furthermore, drug users tended to avoid sports and co-curricular activities to avoid being tested for drug use. However, recently a random drug test routinehas been introduced in the majority of public schools in this country. According to Leonard (2011), this approach of testing drug use has been providing great promises both as a preventive tool for drug use and as a means of reducing the costs of drug use in the society.However, teachers and other members of the public schoolfraternityare not included in this drug testing process. Drug use in public schools has severa l negative effects. Gasper (2009) identifies the issue as one of the major causes of students dropping out of schools. This is because of the fact that it could make the students feel unfit for the learning environment provided in public schools. It is also related to social problems like lack of discipline in schools, premarital sex, and spread of STIs (Ryan & Cooper, 2008). This indicates that if allowed to increase, it would result to increase in these identified social problems. Drug testing is one way of identifying drug users in public schools. As a policy, it requires that the test results be kept in confidential files and be released to educationpersonnel only when needed (Alexander & Alexander, 2011). However, very few school administrators meet what this policy requires. This results in violations of people’s privacy and victimization of students in public schools.Such outcomes have motivated human rights advocates to propose that drug education should be employed i nstead of drug testing. According to Wilson and Kolander (2011), drug education encompasses all activities aimed at teaching and communicating issues related to drug use to people in order to assist them in avoiding such harm. This might eliminate the negative effects of drug testing and yet achieve the required results in terms of

Crisis and conflict are inevitable in capitalist economies Essay Example for Free

Crisis and conflict are inevitable in capitalist economies Essay Marx believed that capitalism was doomed, and he developed an intricate analysis of the law of motion of capitalist society to prove it (Fusfeld 2002, p 50). At one level his argument had a moral basis. He argued that the inherent injustices of capitalism lead ultimately to social and economic conditions, which cannot be maintained (Fusfeld 2002, p 50). On another level his argument is sociological: class conflict- between a decreasing number of increasingly wealthy capitalists and a growing and increasingly miserable working class- will lead ultimately to a social revolution (Fusfeld 2002, p 50). To conclude his Final argument is economic, that the accumulation of capital in private hands makes possible economic abundance; yet accumulation also leads to depressions, chronic unemployment and the economic breakdown of capitalism (Fusfeld 2002, p 50). At each level the idea of conflict is emphasized: conflict between ideal reality, between capital and labor, and between stagnation (Fusfeld 2002, p 50). Out of conflict comes change, and in this respect according to Marx, capitalism must give way to another society in which conflict is replaced by ethical, social, and economic harmony. Furthermore, Marx argued that the crisis would become deeper and severe longer as capitalism developed. Student no. Z3220293 However Marxs analysis of conflict within capitalist societies was limited by his theory of the laws of motion. He argued that conflict between classes created by an unequal distribution of wealth, and would ultimately lead to an unsustainable social situation prompting the demise of the world capitalist system. Thus, he perceived class conflict as the fatal flaw of capitalism. However his detractors would argue that conflict of some form exists in all human interactions and thus has existed in all political and economic systems, concluding that capitalism addresses this inherently human conflict in order to avoid crisis. In a capitalist society according to Marx, the two great economic interests are those of a capitalist and worker. These two classes stand opposition to each other, since the capitalist can prosper only if the worker is exploited. In this respect capitalism is only the latest in series of social organizations in which one class exists at the expense of another, stated in the communist manifesto. Marxists would further argue that peoples dominated politically or economically by great capitalist nations now bear the burden of exploitation, poverty and unemployment However as a proof of Marxs errors, his detractors point to the rising living standards of modern nations. The working class has not been subjected to growing misery, and labor unions have gained economic and political power in all major industrialized countries (Fusfeld 2002, p 50). Moreover, the working class Student no. Z3220293 has shared the increased wealth, income, and economic benefits that have been spread widely throughout all social classes. In spite of all the concessions that have been made to the working class, such as social welfare legislation, union organization and higher living standards Marxists contend that the basic defects of capitalism remain, holding back economic growth and postponing the emergence of the abundant society (Fusfeld 2002, p 50). Nevertheless Marxs prediction of the triumph of socialism and the creation of democratic, egalitarian, and nonexplotive society has not proved accurate. Capitalism was placed on the defensive by the rise of communist regimes in Russia and China, and by the spread of socialism through many of the less-developed countries (Fusfeld 2002, p 60). But in most instances, these non-capitalist economies developed authoritarian political regimes, new forms of economic and social inequality, and new aspects of exploitation. Ultimately Marx argued, as Fusfeld states ( 2002) the economy could achieve widespread abundance and produce enough for all, and at that point in human history all people could be completely free, both politically and economically. Further more Marxist economics suggested that capitalism could not achieve this Student no. Z3220293 goal, as it prevented the full development of modern technology and resulted in periodic stoppage of capital accumulation. However, it is evident that under capitalism technology has flourished. More so capitalism has provided the push for new productive industries, as it is a continued to growing and change. Thus such an economy offers more opportunities then a stagnant one. For example China is the manufacturing hub of the globe. Even though China has its roots in communism it is still regarded as an extremely influential capitalist society. Its cities are booming. There are more building cranes in china than in all the United States. Chinas super-highways are filled with modern cars. Its research and development centers are state of the art. At the rate its growing, China will soon be the largest economy in the world. In these respects it is evident to conclude that under capitalism economies have grown and benefited, due to its productive nature. Further more, in a Marx perspective, labor under capitalism is exploited as it is not paid the full value of the products and services it produces. The capitalist employs workers at the current wage rate and works them for as many hours each day as possible, making sure that the value of the workers output is greater than the wage paid (Fusfeld 2002, p 61). This difference between the wage and the value added by the worker, which Marx refers to as surplus value, becomes the capitalist profit. Exploitation of the worker can be intensified, and the surplus Student no. Z3220293 value appropriated by the capitalist can be increased, by an employers efforts to achieve lower wages, longer hours and an employment of greater number of women and children. Marx was correct in some respects, for example developing countries at present are experiencing high rates of exploitation. Women and children whom work in such exploitive environments in china for example for less then a few dollars a day are the truth in Marxs theory. More so, Marx critique of capitalism included a forecast of its inevitable break down. In some instances capitalism has served as an unstable society, which has been suffocated with conflict and crisis. For example the great depression and the 1987 recession. In both instances the economy had if not almost hit bottom. In a Marxist view this could be concluded as the demise of capitalism. However his detractors would argue that conflict of some form exists in all political and economic systems, concluding that capitalism addresses this inherently human conflict in order to avoid crisis. Which in some respects is true. For example on black Monday of the October 1987 when a stock collapse of unprecedented size lopped twenty-five percent off the Dow Jones industrial average. The collapse, larger than that of 1929, was handled well by the economy and the stock market began to quickly recover. More so during the great depression certain strategies were adopted to deal with the crisis. The new deal was the name given by President Franklin D. Roosevelt of programs between 1933-1938 with the goal relief, recovery and reform of the United States Student no. Z3220293 economy during the great depression. The new deal had three components, direct relief, economic recovery and financial reform. In these respects one can observe the recovery of capitalist economies and their ability to continue to grow. To conclude it is evident that crisis and conflict is inevitable in capitalism however such an economic system is able to adapt and recover from such conflict. References student no. Z322093 Campbell, D 1996, the failure of Marxism-the concept of inversion in Marxs critique, Dartmouth Press, London Cohen, G A 1978, Karl Marx theory of history, Oxford University Press, London Culter, A, Hindess, B, Hirst, P Hussain, A 1977, marxs capital and capitalism today, Routledge Kegan Paul Ltd, London Fusfeld, D 2002, the age of the economist, 9edn, Addison Wesley Press, Harman, C 1995, how Marxism works, 5edn, Bookmarks Press, Sydney. Worsley, P 2002, Marx and Marxism, revised edn, Routledge Press, London

First auditors of Gadget limited Essay Example for Free

First auditors of Gadget limited Essay 1. Identify the independence factors, and any other issues, that you and your co-partners in Ernest Peat Co will need to consider in order to determine whether your firm can put itself forward to act as the first auditors of Gadget limited and the measure that may be taken to resolve any perceived conflicts. The purpose of an audit is to provide an independent Examination by an appropriately qualified person for the benefit of interested parties to whom the auditor reports to. The principle of auditor independence is established via the Companies Act, and also an ethical code. Auditors are therefore expected to be independent of those whose work they are auditing and to whom they are reporting. There are two types of audit independence 1- Practitioner independence 2- Profession independence Practitioner independence: is the state of mind of the actual auditor. There are three types of independence that may determine whether independence has been put at risk. Michelle Bond is a substantial shareholder in Gadget Limited, however she is not a director. Her rights as a shareholder does however has some bearing on the decision making process however only on an influential not binding basis. Independence becomes an issue as to whether the objectivity of Earnest Peat Co can be maintained. Basil Bond must be seen to be acting objectively in order to provide an independent view of the company and not on the conflicting interest of protecting his sisters investment. The Companys Act 1985 does not disqualify a shareholder or debtor/creditors of the company or close relative of an officer/employee for that matter, but each RSB has an ethical code, which includes threats to independence, and objectivity which would normally disqualify the auditor in the circumstances cited. Jenny Jordan, has also anticipated that she will also engage your firm to act as tax advisors. By providing additional services as well as performing the function of auditor the issue of independence may be raised in a both positive and negative light. The provision of other services may increase independence because of the value of the auditor to the client , i. e. due to value of service, and therefore there will be increased dependence of the client on the auditor. This essentially reduces the pressure of the client and results in the perception of greater independence On the other hand the greater the dependence of the auditor on the client because of the value of fee, thus reduces the auditors liability to withstand pressure and there independence is at risk. Jenny Jordan has enquired whether you or one of your partners could act as company secretary As auditor, Earnest Peat Co. must members of an RSB as an overall prerequisite for eligibility to act as a corporate auditor. At the individual company level the CA 85 states that a person is ineligible for appointment as auditor if he or she is an officer or employee of the company a partner or employee of such a person a partnership in which such a person is a partner. In light of this is a member of Earnest Peat Co. is appointed as company secretary, he or she couldnt be appointed as auditor as well. Other issues that may be of some relevance Size of firm: the audit firm; Earnest Peat Co comprises of three partners and therefore considered to be a small audit firm as opposed to large firms comprising of large numbers of partners and professional staff spread throughout the world with many offices. Resources Expertise Earnest Peat Co. must ensure that there are adequate resources for example staffing the audit with staff with the necessary expertise in order to maintain the integrity of the audit independence. Earnest Peat Co. comprises of three partners who are registered auditors and accountants and therefore it must be questioned whether or not this is enough. This is can be used as an indication of the dependence of the audit firm on the client, as Earnest Peat Co are of a small nature the portion of fee generated by taking on Gadget Audit may exceed 10% of the practices annual income, hence over reliance to obtain the contract to act as auditors will have an adverse affect independence, as Gadget may go elsewhere.

Operational Requirements And Service Conditions Of Piston Engineering Essay

Operational Requirements And Service Conditions Of Piston Engineering Essay ABSTRACT There is an extent in changing the trend of the material by its properties and its characteristic. The majority of the materials completely depend on the application of the material in the component and its versatility. The components by material vary from each other by its properties. The materials have the tendency to change its manufacturing process by its character. A component can be manufactured by using various materials depending according to the application and its life. In this paper we discussed about the manufacturing process of the components like piston, connecting rod and the crank shaft. The alternative methodologies and usage of alternative materials are also explained by using CES chart with its advantages. INTRODUCTION Selecting the appropriate material is an integral part of the successful implementation of an engineers design. A design engineers ability to objectively quantify the combined marketing, technical and manufacturing requirements as they apply to the material selection is critical to the actual as well as the perceived success of the product. This paper contains a deep knowledge about the selection of the material and its manufacturing procedure with justification. CHAPTER 1 GENERAL COMPONENT DETAILS 1.1 PISTON The piston is the most essential component of the engine which actually transfer the energy output from the combustion chamber to the crankshaft through connecting rod. This is a pressure-tight cylindrical plunger which is subjected to the expanding gas pressure. Basically, piston structural components are head, skirt, gudgeon pin, grooves and lands. 1.1.1 OPERATIONAL REQUIREMENTS AND SERVICE CONDITIONS OF PISTON Hence in order to transmit this high power output the piston must be designed lightly and must be robust. The piston must be of higher strength material that can with stand the high pressure that is been generated due to the burning of air-fuel mixture within the cylinder. Piston must be fitted properly to control the expansion due to temperature, without which the piston will fit loosely when in cold and they bind themselves when it gets warmed. 1.1.2 FUNCTIONS OF PISTON Transmit energy from combustion unit to piston pin, Serve as a carrier for the piston ring which seals the compression in the cylinder, Act as a guide for upper end of the connecting rod, Withstand high temperature expansion Despite the heat energy to the coolant. piston.gif Fig(1) Piston Assembly Conditions of piston at normally high speed, Piston moves from the top to bottom of the cylinder and vice versa with a acceleration of speed of around 50mph at midpoint and decelerates. The piston is subjected to pressure of about 6.8MPA. The piston is subjected to temperature of about 315 °C.[1] 1.1.3 DESIRABLE MATERIAL CHARACTERISTICS The Piston materials must meet the following conditions, [2] Low thermal expansions for arresting the hot gases. High thermal conductivity for releasing heat from piston head. High strength to mass ratio (light weight) for transmitting high power output. High fatigue strength for increasing the material strength. Good resistance to surface abrasion. To reduce skirt and ring groove wear. 1.2 CONNECTING ROD Connecting rod is a part of the engine which connects the piston to the crankshaft. This connecting rod converts the linear motion of the piston to rotating motion to the crankshaft. 1.2.1 OPERATIONAL REQUIREMENTS AND SERVICE CONDITIONS [] Connecting rods should be made as long as possible to reduce the oblique angle by the cylinder axis. Both tensile and compressive stresses are produced due to piston reciprocating-inertia loads. In order to evade scuffing proper lubrication is needed. Lubrication of the small end by a hole drilled along the shank should be so arranged that the hole intersects the big end bore circumferentially. To prevent buckling the rod shank is made in an H section, i.e., with a central web and two end flanges. Intense heat is generated at high rotational speed, so large bearing area is required to make the rod wear well. They should be checked for the correct length, weight distribution, straightness and freedom from twist. 1.2.2 FUNCTIONS OF CONNECTING ROD As the word is self explanatory, the connecting rod connects the piston and the crankshaft. The connecting rod continuously transmits energy from the combustion chamber to the crank shaft. It actually converts the reciprocating motion of the piston to the rotary motion of the crankshaft. These dynamic motions of the connecting rod makes it as light as possible whilst having a rigid section. 14900_19847.jpg 1.2.3 DESIRABLES MATERIAL CONDITIONS Must be strong to remain rigid under loading and light enough to reduce the inertia forces. Material must have good elastic modulus. It must have high fatigue strength in order to avoid failure due to high cycle fatigue. Heat capacity of the connecting rod must be high. Must withstand buckling stress due to large compressive loads. Must be of low density to avoid bearing failure. 1.3 CRANKSHAFT Crankshaft is the central link-up for the power produced by each cylinder in the engine. This crankshaft is one of the heavier part of the engine which is to be made strong to withstand the load from the con-rod. 1.3.1 OPERATIONAL REQUIREMENTS AND SERVICE CONDITIONS Fillet areas locations are to be verified since both torsional and bending loads are experienced during its service life. Counterbalancing of weight is to be considered in order to counteract the centrifugal forces created by crankpin. The projected areas of the big-end and main-end journals must be adequate to withstand maximum cylinder pressure. After grounding should have a surface finish of 0.5 µm to minimize bearing wear. Crankshaft must have the capacity to absorb the thrust loads from clutches or torque converter. 1.3.2 FUNCTIONS It transmits power from combustion chamber to the flywheel through piston, piston rings and connecting rod. It harness and phase the individual cylinders power impulses transmitted through the mechanism of the connecting rod which converts the reciprocating motion of the piston to rotary motion at crankshaft. It changes the linear displacement due to sudden shock caused by the combustion chamber into smooth rotary motion which is the input to many devices. Crankshaft rotates in the cylinder in the cylinder block of the main bearing which supports the crankshaft which reduces the excessive wear. http://www.motorera.com/dictionary/pics/c/crankshaft.gif 1.3.3 DESIRABLES MATERIAL CHARACTERISTICS Material nominal stress must not exceed 20% of tensile strength in bending and 15% in torsion. Must have the capacity to withstand large force from gas combustion. Must have high heat withstanding capacity. Must have low thermal expansion. Must have high adequate strength, toughness, hardness, and high fatigue strength. CHAPTER 2-MATERIAL SELECTION 2.1 MATERIAL SELECTION FOR PISTON[hh] Material selection process is an integral part of the overall product development process and must be considered in the early phases of the product definition. The material chosen for manufacturing the product is based on the following consideration, Mass consideration Strength and wear consideration Heat-conduction consideration Expansion consideration Based on the above considerations the aluminium alloys satisfies all the factors comparing to cast iron and steel. Mass consideration: Since the pistons reciprocating force is high at high speed, it is necessary to turn to light material instead of cast iron and steel. It has a relative density of 2.6 when compared with 7.8 for cast iron. Strength and wear consideration: Since pure aluminium has low tensile strength of 92 to124 N/mm2 and fall of to 31N/mm2 at 300 °C, it is always alloyed with copper or silicon for piston materials which improves the strength to mass ratio. At high level of silicon, the alloy exhibits excellent surface hardness, wear resistance properties and excellent dimensional stability. Heat-conduction consideration: The better heat dissipation of aluminium-alloy pistons compared to cast-iron pistons greatly reduces the maximum piston-crown operating temperature of 250C 300C for allou pistons and 400 to 500C for cast iron. Expansion Consideration: The thermal expansion is less for Al-Si alloy which has a thermal expansin of 0.000 021 and 0.000 017 per  °C for 12% Si alloy and 22% Si alloy. Fig() CES chart 2.1.1 SURFACE CONSIDERATON: Due to high speed reciprocation of the piston there may be so many losses or issues that must be considered. In that the frictional losses in piston assembly are majorly due to generation of heat. Subsequent raise in temperature can have this effect in the operation. In order to overcome this problem, proper material with good thermal conductivity is chosen. 2.2 MATERIAL SELECTON FOR CON-ROD The connecting rods are crucial and highly stressed component of the automotive engine subjected to alternative tensile and compressive stresses. Hence the material must be chosen based on the following conditions; Good elastic modulus, High fatigue strength, Low density to avoid bearing failure and High heat capacity. Based on the following conditions microalloyed steel is chosen which meets all the requirements mentioned above. This steel has a hardness level of 20-30 HRC. Small microalloying additions of vanadium and niobium are used to increase the strength of carbon steel plates. 1.1%Mn-0.5%Cr is the best combination to obtain thee high fatigue strength. Lowering the carbon content down to 0.33% and increasing the vanadium content to control the hardness gives toughness which improves the fatigue strength of free machining grades with S and Pb. The finally obtained chemical composition is 0.33%C-1.05%Mn-0.5%Cr-0.12%V-.055%S-0.20%Pb-Ca which has fatigue strength of 26% higher than a conventional microalloyed forging steel. As for connecting rod, application of light metal like titanium alloys and aluminium alloys are been tested, due to high cost in light metal the connecting rod are made of microalloyed steel. This structure contains ferrictic-pearlitic-bainit. Fig() CES chart 2.2.1 SURFACE CONSIDERATION The connecting rod is one of the highly stress concentrated part of the automotive engine. It is known that in the four cycle engines the connecting-rod small end is particularly stressed when the con-rod is at top dead centre at the beginning of the induction stroke, since the small end is ovalized by the tensile inertial forces exerted by the mass of the piston assembly. During both the stroke condition (expansion and compression) gudgeon pin pushes the small end along the lower end of the arc, by which the compression load directly acts on the con-rod without considerably stressing the eye. The eye is therefore subjected to repeated stresses, whereas the con-rod shank stress are reversed.(10) 2.3 MATERIAL SELECTION FOR CRANKSHAFT (hh) Crankshaft are from materials which can be readily shaped, machined and heat-treated and which have desirable mechanical properties such as adequate strength, toughness, hardness and high fatigue strength and of course , low cost. The highest quality steels are usually specified for satisfying the constraints given. Metals with optimum combination of bending and the stiffness are identified by creating a charts in CES by using performance indices in axes. From the figure it is clear that the low carbon steel, high carbon steel, low alloy steel and medium carbon steel are satisfying the given constraints. Low alloy steel with chromium-molybdenum is used for crankshaft. This forging steel is suitable for medium to heavy-duty petrol and diesel-engine crankshafts. It presents no difficulty in hot working and afterwards can be easily machined to size. The alloying composition is 0.4% carbon, 1.2% chromium and 0.3% molybdenum. 2.3.1 SURFACE CONSIDERATIONS Since crankshaft is the most highly strained part of the engine with high load acting on it the following factors must be considered. Pitting failure can occur in the crank-pin Due to lack of surface integrity lack of control over stress and temperature. CHAPTER 3 MANUFACTURING PROCESS 3.1 MANUFACTURING PROCESS FOR PISTON[SS] Based on the material selected as aluminium alloys for piston, the manufacturing process is carried-out through casting because of its capability to produce near-net shaped parts at the required production rate. Hence the process selected for this component is the Gravity die casting. 3.1.1 GRAVITY DIE CASTING The pistons are produced from high-silicon alloys, such as 413.0 aluminium alloy. This alloy has high fluidity and can create high-definition surfaces through permanent mould casting; it also has high resistance to corrosion, good weldability, and low specific gravity. The universal acceptance of aluminium pistons for internal combustion engine applications is due to mainly to their light weight and high thermal conductivity.[ss] This type of casting is suitable for high volume production. The main advantages are the dimensional accuracy and surface finish. Castings ranging from few grams to 100kgs of aluminium alloy could be casted. This process could achieve higher mechanical properties than other casting by heat treatment. Since silicon has got good properties like, low shrinkage and imparting high fluidity which results in good casting. The maximum amount of silicon in cast alloy are in range of 22%-24%.(11) Manufacturing route: [ss] The h13 tool-steel mould is preheated to 200 °C to 450 °C, depending on the cast alloy and part size. Initially, the preheat is achieved with a hand-held torch, the mould reaches a steady-state temperature. Molten aluminium is heated to between 100 °C-200 °C above its liquidus temperature as shown below. Once the molten shot is in place the piston drives the mould in its place. Because of high thermal conductivity of the mould material, heat extraction from the molten metal is rapid and the metal solidifies in small channels before filling the mould completely. [9] 3.1.2 MICROSTRUCTURAL CHANGES Silicon has a diamond crystal structure and is consequently very brittle. These silicon structure damage the mechanical properties and nucleates on aluminium phosphide particles that is present in the melt as impurities. Further addition of sodium to the melt getters the phosphorous, which thereby increases the difficulty of sodium nucleation. Solidification is suppressed to lower temperature where the nucleation rate is large. This leads to remarkable refinement of microstructure. [9] Aluminium Silicon [9] From the figure above the dark feature is a shrinkage pore caused by a casting defect. This figure shows the coarse silicon plates in an aluminium matrix. 3.2 MANUFACTURING PROCESS Microalloyed connecting-rod is manufactured by a simplified thermomechanical treatment like controlled cooling following hot forging. Through these processes desired properties could be obtained without quenching and tempering treatments. Hence powder forging was selected which would conveniently satisfy the manufacturing process for the selected material and component. 3.2.1 POWDER FORGING Powder forging rods are manufactured by combining metal powders into a pre-form that is sintered and reheated to forging temperature. Then it is completely forged to its final shape and machined to its final dimensions. This mixed powder is compacted at room temperature and high pressure upto to 200 to 400MPa. At the end of the process the powdered material acquires a density of 70 to 85%. This process has resulted in fully dense shape part which makes it suitable for high performance applications where high durability and strength are required. The detailed manufacturing route of this PF process is shown below: [12] The advantages of using PF process are, Good dimensional accuracy Minimum scattering of weight Energy saving [12] 3.2.2 MICROSTRUCTURE [13] [13pdf] From the photograph of the microstructure of the connecting-rod material it is clear that the component contains pearlite and ferrite materials in composition. The above picture clearly indicates that in the powder metal connecting rods oxides are removed from the material surface by shot peening but the oxides are entrapped and remain below the surface causing the crack to originate below the surface . 3.3 MANUFACTURING PROCESS 3.3.1 FORGING [ss] The material selected for the crankshaft is forged steel which has a desirable mechanical properties such as adequate strength, toughness, hardness, and high fatigue strength. Hence the suitable manufacturing process for this steel is forging. Forging is a basic process in which the work-piece is shaped by compressive forces applied through various dies and tooling. For this forging process the dimensional tolerance range from  ±0.5 to  ±1% of the forging dimensions. At higher temperatures of about 700 °C dynamic forging recrystallisation occurs which increases the stress and strain deformation of the metal to make it hard. Manufacturing route: Prepare a slug or billet Heat the work-piece in the suitable furnace For hot forging, preheat and lubricate the dies Forge the billet in appropriate dies and in the proper sequence Clean the forging and check its dimensions Perform additional operations such as heat treatments and straightening Inspect for defects In the hot forging process to form a metal billet two or more dies are brought together to each other at a suitable room temperature in a shape of the die impression. This process follows two basic requirements, The strength of the material must be low so that the die pressure can be kept within the limits. The material should be capable of deforming without failure and should allow required amount of deformation. The flow of metal and die filling are mainly determined by (i) flow stress and cooling ability (ii) friction and cooling effects at the material interface. In this process, definite amount of heat is received by all the parts after machining in heat treatment process. This is mainly carried-out to improve fatigue and wear properties. High quality parts with moderate cost can be made by this process. Thus this process offers high strength to weight ratio, toughness and resistance to impact and fatigue to the material which is considered in the performance of the crank shaft. [14] 3.3.2 MICROSTRUCTURE Heating above recrystallisation temperature causes recrystallisation that removes the microstructure deformed and generated recrystallised grains. After eutectoid-carburizing martensite transformation takes place and a black portion near the surface is formed consisting of fine grains of ferrite and carbide. On quenching from the austentite (ÃŽ ³) phase martensite is formed. This transformation is a diffusion-less shear transformation . Martensite is too brittle in plain carbon steel for practical applications and is subsequently tempered to restore some toughness. CHAPTER 4 ALTERNATE MATERIAL 4.1 ALTERNATE MATERIAL FOR PISTON[hh] Cast iron refers to the family of ferrous alloys composed of iron, carbon ranging from 2.11% to about 4.5% and silicon of about 3.5%. They are classified by their structure ferritic, pearlitic, quenched and tempered or austempered. The equilibrium phase diagram relevant to cast iron is shown below where right boundary is 100%C. The eutectic temperature is 1154 °C and thus cast irons are completely liquid at temperatures lower than those required for liquid steels. One of the major disadvantage of the aluminium as the base metal of the piston is that it has high co-efficient of linear expansion in the range of 0.0000221per °C, compared with 0.0000117per °C of cast iron. Aluminium has twice the expansion rate of cast iron. Cementite is metastable (not completely stable) which has a tremendously low decomposition rate. However it can be made decomposed into alpha-ferrite and graphite. The graphitization can be controlled, promoted and accelerated by adding silicon, controlling the rate of cooling and modifying the composition.[ss] [15] 1.4.1 LIMITATIONS Relative density is high of about 7.8 When in tension, the presence of graphite acts as a stress riser weakens the material. Strength properties of the cast iron are significantly affected by the shape and size of graphite. Higher material and manufacturing cost. The major disadvantage is the shrinkage. 1.4.2 POTENTIAL BENEFITS Presence of graphite in cast iron improves wear-resistance as it acts as a lubricant. High carbon content-degradation of ductility and fracture toughness. Good corrosion-resistance. Easy machinability Wide range of composition and microstructures-easy weldability. 4.2 ALTERNATE MATERIAL FOR CON-ROD The alternate material chosen for connecting rod is aluminium alloyed material as it is light in weight and provides long service life to the part. The aluminium alloys are high strength-to-weight ratio, resistance to corrosion by many chemicals, high conductivity and ease of formability. The material composition of aluminium is 7.6 to 8.4% Zn,1.8-2.3%Mg, 2-2.6%Cu, 0.08-0.25%Zr, 0.10%Si, 0.15%Fe, 0.05%Mn, 0.04%Cr and 0.06%Ti. When compared to othe alloys it convinces the constrains like low thermal expansion, wear-resistant, high fatigue strength and buckling. Majorly this material is chosen based on the following consideration: Mass consideration Strength and wear consideration Expansion consideration Heat-conduction consideration http://www.streetperformance.com/ART/PRODUCTS/100687/14012-8.jpg[19] 2.4.1 LIMITATIONS It is more expensive than cast iron. Low dimensional accuracy and poor surface finish. Solidification is very slow. Occurrence of fracture in short transverse direction. Expansion rate is high when compared to cast iron with oure aluminium. 2.4.2 POTENTIAL BENEFITS Aluminium alloys can be easily machined and welded and formed. High dimensional accuracy with long service life. High yield strength in both tensile and compression. Aluminium is much better conductor of heat than cast iron. Aluminium alloys provide improved resistance to abrasion and produce strength over temperature range. Improves the performances of the piston and thus the engine. 4.3 ALTERNATE MATERIAL FOR CRANKSHAFT As the crankshaft is the heavier moving part in the automotive engine, the material selected for this part has to be strong and light. Titanium alloys having high strength with reduced weight is used for crankshaft until and unless cost is not considered, as this material is very expensive. http://amt-advanced-materials-technology.com/s/cc_images/cache_867254901.jpg[17] 4.3.1 POTENTIAL BENEFITS OF TITANIUM ALLOYS Titanium has high melting point of about1678 °C which specifies strong creep and strength above wide temperature range. The density is about 55% of steel with comparable strength. Ti alloys exists in two allotropic forms ÃŽ ± and ÃŽ ² Presence of thin oxide surface film-resistance over atmospher and sea environments including chlorine and organic chemicals. Reacts rapidly with oxygen, nitrogen and constituents in cutting tools at high temperature. 4.3.2 LIMITATIONS Embrittlement occurs during fabrication because of susceptibility of hydrogen, oxygen and nitrogen. Forging with titanium alloys is expensive but it increases the strength of the material. Ti alloys has a tendency to madden when tightening with connecting rod using bolt. Titanium is more difficult to machine due its reactive nature. Niobium Titanium[16] CHAPTER 5 ALTERNATE MANUFACTURING PROCESS 5.1 ALTERNATE MANUFACTURING PROCESS FOR PISTON 5.1.1 SAND CASTING Sand casting is a one of the most feasible manufacturing process where the unit production is comparatively less. In this process a mixture of sand and clay is compacted around the pattern in which the pattern retains the shape of the original component to be produced. Then the pattern is removed in order have the cavity in the shape of the pattern. Generally low cost wooden patterns with gateways and runner are used. The molten metal is poured into the gateway by which it runs through the runner and fills the cavity and forms the exact shape of the cavity. Actually this whole system is housed in a box called flask. After which the molten metal allowed to solidify by cooling it. As the molten metal is solidified the sand pattern is broken and final work is done to obtain the finished component. The figure below shows the manufacturing process of the sand casting in detail. http://openlearn.open.ac.uk/file.php/1689/T173_2_020i.jpg Fig(8.1) Sand Casting Process [18] 5.1.2ADVANTAGES Low tooling and equipment cost Component with any complicated shape can be produced Relatively cheap process Possibly components can be produced in large quantity. 5.1.3 DISADVANTAGES High tolerance ratio is required Labour cost is high. 5.2 ALTERNATE MANUFACTURING PROCESS FOR CON-ROD 5.2.1 SQUEEZE DIE CASTING Squeeze die casting or liquid metal casting involves the process of solidification of molten metal under high pressure. The machinery includes a die, punch and ejector-pin. Under the pressure applied by the punch keeps the entrapped gases in solution and the rapid heat transfer takes place at the die-metal contact which results in fine microstructure with good mechanical properties.[ss] Elimination of shrinkage and gas porosity happens because of precise metal metering, quiescent die filling and high pressure. 5.2.2 ADVANTAGES Precise dimension, Excellent surface finish, Fully shaped component is obtained Complex part can be made to near-shape. 5.2.3 DISADVANTAGES High initial cost Limitation of high fluidity metals[20] 5.3 ALTERNATE MANUFACTURING PROCESS FOR CRANKSHAFT 5.3.1 FORGING In forging operations the metal is squeezed to shape by die in which the metal is subjected to large plastic deformation. These metals are placed in-between closed dies under high temperature and pressure which results in succession of the final shape. http://www.forcast.ca/images/00436_faq1.gif[21] Forgings generally are subjected to additional finishing operations, such as heat treating to modify properties and machining to obtain accurate final dimensions and surface finish. 5.3.2 ADVANTAGES Good utilizations of materials Good dimensional accuracy High production rate Good reproducibility Low die costs 5.3.3 DISADVANTAGES Initial cost is high Not economical for small quantities Machining often necessaries

Oscar Wilde :: essays research papers

Oscar Wilde Oscar Wilde (real name Oscar Fingal O'Flahertie Wills Wilde) was born on October 16th, 1854 in Dublin. His father, William Robert Wilde, was an eminent eye doctor, with an interest in myths and folklore. He was the founder of the first eye and ear hospital in Great Britain, as well as the appointed Surgeon Occultist to the Queen, who knighted him. His mother, Jane Francesca Elgee Wilde, was a poet who wrote patriotic Irish verse under the pen name Speranza, and had a considerable following. As a youngster, Wilde was exposed to the brilliant literary talk of the day at his mother's Dublin salon. In 1864 Wilde entered the Portora Royal School at Enniskillen, and in 1871 entered Trinity College in Dublin. In 1874 he left Ireland and went to England to attend Magdalen College at Oxford. As a student there, he excelled in classics, wrote poetry, and incorporated the Bohemian life style of his youth into a unique way of life. He came under the influence of aesthetic innovators such as English writers Walter Pater and John Ruskin. He found the aesthetic movement's notions of "art for art's sake" and dedicating one's life to art suitable to his temperament and talents. As an aesthete, Wilde wore long hair and velvet knee breeches, and became known for his eccentricity as well as his academic ability. His rooms were filled with various objets d'art such as sunflowers, peacock feathers, and blue china. Wilde frequently confided that his greatest challenge at University was learning to live up to the perfection of the china. Wilde won numerous academic prizes while studying there, including the Newdigate Prize, a coveted poetry award, for his poem Ravenna. In 1879 Wilde moved to London to make himself famous. He set about establishing himself as the leader and model of the aesthetic movement. Besides his hair and breeches, he added loose-fitting wide-collared silk shirts with flowing ties and lavender colored gloves. He frequently carried a jewel-topped cane and was caricatured in the press flamboyantly attired and holding an over- sized sunflower, an icon of the movement. Wilde quickly became well known despite having any substantial achievements to build on. His natural wit and good humor endeared him to the art and theater world, and through his lover Frank Miles, he found it easy to become part of the cliques that frequented London's theater circuit and drawing rooms. He became a much desired party guest, and eventually his popularity led to his being chosen as an advance publicity man for a new Gilbert and Sullivan operetta, Patience, that spoofed

Lord Of The Flies Essay -- essays research papers

How mankind can’t survive without rules and laws   Ã‚  Ã‚  Ã‚  Ã‚   Could civilization live a normal and stable life, without any rules and orders to obey? Could you picture, New York City, with no laws to follow and everyone doing as they please? Just imagine the disasters that we will experience. In the novel, Lord of the Flies, written by William Golding, we see how each individual character reacts differently to the exposure of complete freedom from an organized society. Also, awe see how this separation from a structural society causes chaos among all these different characters.   Ã‚  Ã‚  Ã‚  Ã‚  The story begins with 20 pre-adolescent boys who are on an airplane and the airplane crashes on a remote jungle-island, which is a very effective setting to establish the idea of savagery. The setting of the story is very important because it shows how the boys are given their own paradise and destroy it. The airplane crew is killed and the boys are left on their own, with no adult supervision. At the beginning of the story, we meet the character, Ralph, the protagonist of the novel. Ralph is an example of the ethical citizen, intelligent and responsible but, on many occasions, is caught up in the opinion of others. The leadership that Ralph offers isn’t as stable and organized because he isn’t able to control the â€Å"littluns† and the others after a certain point. This is when the society that Ralph tries to create starts to break apart and Jack takes control.   Ã‚  Ã‚  Ã‚  Ã‚  Then immediately comes Piggy, a chubby asthmatic but intelligent kid, who becomes â€Å"friends† with Ralph. He is teased relentlessly by the other boys but is highly respected by Ralph for his ability to think. Piggy is considered the adult voice on the island, which often spoils the fun for the other boys. He also becomes Ralph’s right-hand man. Whenever Ralph can’t think straight, Piggy is there to put some common sense into him. Just like Ralph, Piggy wants to be rescued desperately. A while later, Ralph finds a conch. He then uses the conch to call upon the other kids. The conch is presented as a symbol of authority and order. It is used to summon all the boys from the island to the assembly and it gives its holder the right to speak. The conch also sets Ralph apart from the other boys and is what helps him be categorized as chief and leader. The c... ...ll Ralph because he feels that by doing this he will remain chief and leader and he will take away the idea of being civilized and having a democracy. Again we see how the fire symbolizes power but this time differently because instead of being used for survival and rescue it’s used as destruction and as a weapon for hunting. Jack uses the fire by burning a thicket where Ralph is hiding to be able to take him out. He then hunts him down to mount his head on the sharp stick like the pig’s head. Jack loses complete sense of his mind and is definitely stripped away from what is considered civilized. His immoral actions take the best of him and the others in the island and led them all to forget what is truly important, which is to be rescued. At the end, they are rescued and Ralph is saved from being killed from Jack and his tribe. The novel, Lord of the Flies, gives you, the reader, a clear image of how easily a society could fall apart if we allow ourselves to only live by the day and not care what tomorrow brings. Also, it shows how a society can’t survive without any rules to be followed and that there must be laws and rules in order, to have an established society to live in.