Econ Essay Example | Topics and Well Written Essays - 250 words - 7

Econ - Essay Example n, Jagdish Bhagwati conveys both the India and china’s remarkable upturn of GDP in late 1980s and early 1990s, which resulted from the abolition of trade barriers. This illustrates how trade liberalization usually does to the global states’ economies owing to its free interaction characteristic besides thriving trade across their boundaries. Jagdish Bhagwati believes the remedy to the current global economic crises only rests in adopting trade liberalization or free trade rather than the present protectionism (Bhagwati 38). Jagdish Bhagwati refutes â€Å"Section 24 allowance† orâ€Å"allowance for Preferential Free Trade Agreements (FTA)† which the current US regime is applying besides other global states (Bhagwati 20). Since it yields to numerous economical predicaments presently faced by the global states’ besides posing the issue of economic unpredictability. This is evident in the incumbent US regime where the president Obama prefers protectionism approach and seems to forget its grievous impacts on economy notably in 1930s (Bhagwati 78). Jagdish Bhagwati does not approve the utilization of Preferential Free Trade Agreements (FTA) as a remedy to the present challenges. This is because he refers to the approach as an effective and malicious approach meant to undermine free trade or its liberalization. Therefore, Preferential Free Trade Agreements (FTA) normally erects barriers that prevent the flourishing of economy not only for US but also for other global states (Bhagwati

Should we mine this Ore Essay Example | Topics and Well Written Essays - 500 words

Should we mine this Ore - Essay Example The amount of light that passed through the solutions to the photocells is used to determine the absorbance of each solution (Reynolds & Thompson 26). The equation of the standard curve is given by y =mx + b. Plotting a graph of absorbance against concentration for the standard solutions produces a curve that has a direct relationship with the equation of the standard curve (Bartlett 159). The direct relationship between concentration and absorbance for a solution is referred to as Beer’s law. Concentration of unknown compound can be determined from the graph by measuring its absorbance. Its absorbance is located on the x-axis of the graph, and its corresponding concentration is determined on the y-axis. Concentration of the unknown solutions can also be established from the slope of the Beer’s law curve (Bartlett 159). A blank solution was then prepared by filling the cuvette with distilled water to a volume of  ¾ full. Care was taken not to contaminate the cuvette while filling it. Spectrometer was then calibrated by placing a blank cuvette into the cuvette grove of the spectrometer (Reynolds & Thompson 160). In order to determine optimal wavelength for plotting this standard curve, 0.4 M standard solution was placed in the cuvette slot. The cuvette was then rinsed twice with 1 mL solution in Test Tube 1, and then refilled to  ¾ of its volume. The outside was wiped with a tissue paper and placed into the cuvette, and absorbance of the solution was measured (Bartlett 159). This process was repeated for solution 2-5 until their absorbances were obtained. The absorbance of each solution was recorded in the data table. The data recorded was used to draw a graph of absorbance Vs concentration. The concentration of Copper (II) sulfate was obtained from the graph by determining its corresponding rea ding on the y-axis. Among all the acids

Politics and Religion Essay Example for Free

Politics and Religion Essay Do Religion And Politics Go Hand In Hand? Of Course They Do! Religion in politics has long been a taboo subject or elusive topic to most as they argue that they cannot cohesively coexist together when in all actuality they can and do coexist together. Religion and politics essentially belong together like mashed potatoes and gravy so to speak. However, all around the world the extent to which they coexist varies depending on the cultural influence as well as historical significance pertaining to their area. Religion plays a huge role in American politics. During the 2012 election year people were polled on the importance of religion in their lives and 56 percent said that it is â€Å"very important in their lives. † (Miller) Religion plays a substantial role in politics from influencing how some politicians will cast their vote on certain issues to persuading voters to vote for one candidate or another. Although America prides itself on its religious diversity and separation of church and state however it is a prove fact that religion helps determine who a voter will cast their ballot for. A Gallup poll from June of 2012 discovered that 58 percent of Americans would vote for a Muslim candidate while only 54 percent of Americans would vote for an atheist candidate. When polled it also found that only 1 in 5 Americans would vote for a Mormon candidate which could have essentially cost Romney millions of votes due to his religious preference. Indeed we have seen religion play a very influential role in politics in 2012. Religion and politics were very closely tied together during the presidency of George Walker Bush. â€Å"In the eyes of a lot of people religion played a bigger role in government than usual during the presidency of George W. Bush. President Bush evoked God in his speeches more often than other presidents, stated in interviews that God advised him on certain actions and that he firmly believed that he was enacting God’s will as the chief executive of the United States. (Oganesian) Even our Declaration of Independence closely ties religion and politics together with such statements as, â€Å"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights that among these are life, liberty and the pursuit of happiness. † Notice that Creator is capitalized and undeniably it states that we are endowed certain unalienable rights from our Creator. This can either be someone’s higher power if they choose to call it by that name or simply it could be God. Does religion truly belong in politics? This may very well be one of the toughest questions ever asked in this day and age. Religion delves on the belief in good and morality while politics are the workings and dealings of the administration of government. We are a Nation that was founded on Moral Values, Decency and the rule of law. God’s laws will always play a part in politics. If you examine our money even it says,† In God We Trust. † Truly separation of church and state will never be fully successful. When our President is sworn in to the oath of office even he has to swear on a Holy Bible. Is he not the highest ranking government official in our nation? Yet even he has to follow the rules and guidelines that deal with religion. Over and over again we see how closely religion and politics are actually entwined with one another. According to Djupe and Olson, psychological approaches to the study of religion and politics â€Å"view the key attachment point between religious faith and political commitments as the individual’s identification with religious reference groups† (2007:256). Leege and his colleagues noted that the psychological power of group identification is essential to religion’s effect on politics. For example, groups form the basis of cleavage in a larger society for a variety of cultural and political reasons: (1) whether based on voluntary affiliation or generational replacement, groups socialize members into their values ;( 2) through processes of social identification; groups develop consciousness of kind so that it is possible for members to say â€Å"we hey†; (3) through the interaction of members, a sense of social cohesion develops that provides reinforcement for group identity and norms; and (4) through an advantageous political shorthand, political elites think of society in terms of groups. (2002:49–50) Political issues such as abortion and even same sex marriages are governed by some underlying religious values. For example, many laws dealing with these issues are either vetoed or not put into law by the people who in turn use their religious values to help them vote on the topic. Many states still outlaw homosexual marriages because when it is put on the ballot those who believe that it is wrong vote against it so such laws cannot be passed. Many top politicians think of society in terms of groups whether they be religious groups or political groups. We live in an increasingly religious world in which faith and belief affect every dimension of our existence, so our politicians better talk about it. (Marshall, 2008) Religion does not exist in solitude or expressly by itself. It molds our fundamental view of the essence of human life and the morality in which we should live our lives. Going back to the Constitution the First Amendment guarantees â€Å"the free exercise of religion and prohibits the establishment of religion by the government. † By guaranteeing the free exercise of religion and prohibiting the establishment of religion by the government these principles are working together to protect religious freedom as well as a diversely thriving and religious landscape. The role of religion in politics around the world is sometimes controversial at best however even in other countries politics and religion are closely tied together. Even in post-communist countries such as Latvia political parties and religious groups have alliances which can sometimes sway their supporters to vote for a certain political force. The â€Å"Harmony Center†, that positions itself as an alliance of several (but not all) Social Democratic parties, also demonstrates special courtesy to the church. (Tcraudkalns, pg5) Even in Australia where their reputation for â€Å"godlessness† dates back to the nineteenth century where most places had pubs before they had a church religion and politics are still tied closely together. Australia has a unique way of describing politics and religion in terms of masculinity and femininity. â€Å"This reference to Australian â€Å"maleness† suggests that discussions of the relationship between politics and religion are always also discussions about gender. The association of masculinity with the public realm and rationality, and of femininity with religious faith and the home, makes this impossible to avoid. † (Bellanta, pg10) Although there has never been an established church in Australia the churches that are large and established have had a specific presence and role in public matters. However secular Australia proclaims to be religion has a new found role for itself which proves it has not been abolished. Gustavo Gutierrez, a Peruvian theologian, has provided since the late 1960s a theological interpretation of the person of God and his work that has been closely linked with human history, and particularly with the poor and the marginalized. (Aguilar pg. 146) Gutierrez believed that a direct connection of the Christian faith and the practice of politics could be felt as a result of Christ’s incarnation. He closely tied together religion and politics through the human commonality and to the practice of religion and politics centered on the poor, on the commandment of love and of service to the marginalized as a way of life and in a new era of hermeneutics and commonality. Gutierrez relied heavily on biblical text to tie together religion and politics through the service of the poor. When reading Gutierrez’s writing there is no concise separation of religion and politics. He clearly stated that the practice of religion as well as the practice of politics must be conveyed through the Christian faith. In the words of Gutierrez: â€Å"We shall not have our great leap forward, into a whole new theological perspective, until the marginalized and exploited have begun to become the artisans of their own liberation—until their voice makes itself heard directly, without mediation, without interpreters—until they themselves take account, in the light of their own values, of their own experience of the Lord in their efforts to liberate themselves. We shall not have our quantum theological leap until the oppressed themselves theologize, until â€Å"the others† themselves personally reflect on their hope of a total liberation in Christ. For they are the bearers of this hope for all humanity. † Nigeria’s view on politics and religion are that they mix like â€Å"snake oil and fire water. † It is said that Nigerians are some of the most prayerful people on Earth however Olaye is upset that politicians speak godly words to one another without acting on it. We are taught in the U. S. enerally not to mix religion and politics I our conversation however that does not ring true in Nigeria because they do quite opposite of that. Although Nigeria’s Federal Executive Council is taking prayer from the beginning of public events they are still going to read the pious words of the second stanza of Nigeria’s national anthem. (Sample: â€Å"Oh God of creation. Direct our noble course. Guide our leaderà ¢â‚¬â„¢s right. †(Olaye) Olaye wishes that Nigeria politicians would stop the hypocrisy and says until they do that their country will continue to suffer. In Egypt even the Secretary General has an interesting view on politics and religion. He expressed hope that Muslims would draw a line so that â€Å"politics does not dominate religion, and religion does not dominate politics†. (Ihsanoglu) Two of the main fears in Egypt right now after the fall of Hosni Mubarak are actually related to religion. They are religious identity politics and the largest minority of the religious demographic Coptic Christians. He believes in mutual respect and non-interference between the Islam religion and Egyptian political order. These beliefs are showing us that all over the world no matter how separate people try to keep church and state they are actually inevitably entwined together with no line of separation in sight. Some well-known republicans such as Mike Huckabee and Billy Graham are well known Christians who also turn their values of faith into the public’s eye. During the 2012 election season Graham was quoted as saying, â€Å"I believe it is vitally important that we cast our ballots for candidates who base their decisions on biblical principles and support the nation of Israel. I urge you to vote for those who protect the sanctity of life and support the biblical definition of marriage between a man and a woman. Vote for biblical values this November 6, and pray with me that America will remain one nation under God. † Some would even say that Democrats do the best to live by biblical principles of taking care of the less fortunate among us who are already among the living. However it could be argued that Republicans take a better stance on the biblical principle of protecting the unborn. Jesus warns against those who aspire to political correctness. He says: †¢let them alone: they are blind leaders of the blind. (Matthew 15:14) †¢Ã¢â‚¬ ¦in vain do they worship me, teaching as doctrines the commandments of men. (Matthew 15:9) †¢Can the blind lead the blind? Will they not both fall into a pit? (Luke 6:39)(The Holy Bible) Even as far back as in Jesus time he himself laid out the foundation of politics and religion being one in the same. In church it is taught that going against what is the law such as speeding is considered sin and goes against the political laws which have been set forth in our society. Therefore religious people must abide by the political values set forth in our society. If you turn the table’s politicians must even be religious to a degree because they consider killing, stealing, etc. to be wrong and thus are religiously entwined to the Ten Commandments. In conclusion I say religion in politics has long been a taboo subject and elusive topic to most as they argue that they cannot cohesively coexist together when in all actuality they can and do coexist together. Religion and politics essentially belong together as they date back to even biblical times. However, all around the world the extent to which they coexist varies depending on the cultural influence as well as historical significance pertaining to their area. We have seen that I places such as Latvia, Egypt, and even Nigeria that religion and politics do go together however the extent of their union depends on their different cultural influences. Religion and politics even though we have been taught do not need to bring up as a singular subject and in fact they actually can be brought up together and should be because they are essentially a married union to one another. Whilst some critics will still argue that religion and politics are a disaster when they are meshed together their will always be people who disagree o the subject. Everyone will never be o the same page when it pertains to religion in politics or politics in religion.

The car industry: Dilemmas

The car industry: Dilemmas 1. Introduction The car industry faces a crucial weight problem resulting from increasing customer demands in terms of safety and performance. This trend leads to fully equipped cars in all classes getting more luxurious and comfortable. To escape from this vicious circle car manufacturers are forced to take action in the form of lightweight concepts. Light metals are seen as a promising opportunity to decrease the weight of a car. An increasing use of metals such as aluminium in the automotive industry shows that there is still large scope for improvements. Using aluminium car body panel is just a representative example of weight-saving effort did by car manufacturers. Aluminium has some properties that make it ideal for car bodies. The strength of aluminium frame and extruded sections is approximately the same as that of steel. However, the rigidity of aluminium is lower than that of steel. That is partly due to the modulus of elasticity of aluminium that is just one-third that of steel. (1) The effect is that aluminium has a higher elastic distortion when exposed to the same force as steel. Therefore the simple replacement of steel by aluminium engine is not an optimal solution as it does not exploit the whole scope of the advantages of aluminium. New ways need to be pursued to make full use of aluminiums advantages as a light weight material, which means it can be supplied in various aluminium alloys. Although the requirement for improved corrosion resistance and light-weighting are significant factors for use low-carbon steels in the manufacture of cars, (1) this traditional material still has some advantage such as higher strength and lower price. Many kinds of steel and aluminium alloys can be found commercially using in producing car body panels. Each material has its own characteristic. 1.1 Steel Steel is known as an alloy consisting mostly of iron, with carbon content between 0.2% and 2.1% by weight. (3) One of the main factors contributing to the utility of steels is the broad range of mechanical properties which can be obtained by heat treatment. For example, easy formability and good ductility may be necessary during fabrication of a part. Once formed very high strength part may be needed in service. Both of these material properties are achievable from the same material. All steels can be softened to some degree by annealing. The degree of softening depends on the chemical composition of the particular steel. (4) Annealing is achieved by heating to and holding at a suitable temperature followed by cooling at a suitable rate. Similarly, steels can be hardened or strengthened. This can be accomplished by cold working, heat treating, or an appropriate combination of these. Cold working is the technique used to strengthen both low carbon low alloyed steels and highly alloyed austenitic stainless steels. Only reasonably high strength levels can be attained in the carbon low alloyed steels, but the highly alloyed austenitic stainless steels can be cold worked to rather high strength levels. (5) Most steels are commonly supplied to specified minimum strength levels. Heat treating is the primary technique for strengthening the remainder of the steels. Some common heat treatment of steels is listed below: Martensitic hardening Pearlitic transformation Austempering Age hardening The recyclability of steel is brilliant and it is economically advantageous to do so. It is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. (6) 1.2 Aluminium-based alloys In the Earths crust, aluminium is the most abundant (8.3% by weight) metallic element and the third most abundant of all elements (after oxygen and silicon). Because of its strong affinity to oxygen, however, it is almost never found in the elemental state; instead it is found in oxides or silicates. Aluminium was isolated in small quantities early in the 19th century and it remained an expensive curiosity until 1886 when discovery of an economic method for its electrolyric extraction. Since then, the emergence of aluminium as a practical, commercial metal has relied primarily on the availability of electricity at economic prices. Aluminium is obtained from bauxite which is the name given to ores containing 40-60% hydrated alumina together with impurities such as iron oxides, silica and titania. Two steps are needed in the production of aluminium. First, alumina is extracted from bauxite. Second, use electrolysis to dissolve the alumina in molten cryolite and a typical electrolyte contains 80-90% of this compound and 2-8 % alumina together with additives such as aluminium and calcium fluorides. (7) Because the cryolite has a melting point as high as 1010?, the electrolysis of it needs a temperature of about 960? which wastes lots of energy and makes the cost of producing aluminium relatively higher. However, a new methodCambridge FFC which comes from the production of titanium, was introduced to China. This method use a NaCl-CaCl2 electrolyte which has a lower melting point of 520?, even lower than the melting point 660? of aluminium. By using alumina and liquid aluminium as negative electrode, the expanded reacting area on negative electrode allows the electrolysis of alumina to happen, which can theoretically reduce the electrolysis temperature to the melting point 660?. This research opens a new chapter of production of aluminium and will dramatically reduce the cost of producing aluminium some day. Generally speaking, about 85% of aluminium is used for wrought products which are produced from cast ingots. (8) The structures of alloys are greatly changed by the various working operations and thermal treatments. Each individual class of alloys behaves differently, with composition and structure dictation the working characteristics and subsequent properties that are developed. Casting aluminium alloys are also important parts of Al. Apart from light weight, the special advantages of aluminium alloys for castings are the relatively low melting temperatures, negligible solubility for all gases except hydrogen, and the good surface finish that is usually achieved with final products. Most of the cast alloys also show good fluidity and composition can be selected with solidification range appropriate to particular applications. (1) Casting alloys normally have mechanical properties that are inferior to wrought products and these properties also tend to be much more variable throughout a given component. 2 Study of possible alloy using for producing car body 2.1 Steel At present, low carbon steel sheet is most commonly used in car body production. Low-carbon steel has good machinability. Its strength and rigidity can fully meet the car body strength requirements, as well to meet the body welding requirements. 2.1.1 Low carbon steel Steel with low carbon content has properties similar to iron. Low carbon steel is the steel containing approximately 0.05-0.15% carbon. Content influences the yield strength of steel because it is a BCC structure and carbon atoms fit into the interstitial crystal lattice sites. (3) These carbon atoms reduce the mobility of dislocations. But it has a hardening effect. Because the interstitial carbon atoms cause some of the iron BCC lattice cells to distort, a high enough stress level must be applied in order for the dislocations to move. Low carbon is one of the most common steel and it is relatively cheap than most other steels. However, the strength is relatively lower, which can be seen in appendix. 2.1.2 Higher strength steel In order to reduce the weight of an automobile, it is absolutely essential to reduce the thickness of the sheet steel and compensate for loss of strength by using higher strength steel sheets. For inner panels, though a rather substantial amount of high strength steel is used, the percentage use is a little lower than in the outer panel due to stiffness limitation and insufficient formability. (9) However, the overall use of high strength steel is estimated to increase further more. The problems in press performance of high strength steel are wrinkles, surface deflection and springback, fracture especially in stretch flanging and galling on the forming tool. Until now, the average level of strength used widely is at most 400 MPa but in the near future the high strength steel with over 400 MPa may be used for the reduction of weight and in this case the forming difficulty will increase further more. (5) The thickness of a panel sheet decreases as a result of application of higher stre ngth steel. Many kinds of microstructural hardened high strength steel sheet are applied by automobile producers. Ø Dual phase steel Dual phase steel show lower yield strength compared with other types of steel having the same tensile strength because of mobile dislocations existing in the vicinity of the boundary of ferritic and martensitic phases. So presents low yield ratios. And thats why its elastic recovery after forming work is small and shape fixability is good. As it also shows larger elongation than precipitation hardened steel sheets and fatigue resistance. (3) Ø Trip steel sheet Transformation induced plasticity steel is also becoming an ideal material for car body panels. It has meta-stable austenite transformable into martensite contained up to 30% in bainite or ferrite and bainite matrix. Commercial Trip sheets have simple C-Si-Mn series chemical compositions. The simpler chemical compositions are made viable by stabilizing the austenite phase through distribution of alloy elements in the two phase region and concentration of carbon into austenite during bainite transformation. (4) 2.2 Aluminium-based alloy Pure aluminium cannot be applied to normal passenger car due to softness. Moreover, surface damages during stamping and handling are often subjected to subsequent surface hand finishing. This additional operation on the panel is usually inevitable. In contrast to pure aluminium, aluminium alloys contain solute additions which can markedly affect grain structures and particularly the microstructures within the grains. This in turn strongly influences the responses of alloys to working and heat treatment. Both crystal structure and microstructure influence mechanical properties. Slip is inhibited by grain boundaries, which are disordered regions, (and so small grains improve strength). Slip can also be made difficult by dispersing particles of another phase throughout the matrix. This indicates the typical hardening mechanism of aluminium. (9) There are some kinds of wrought aluminium alloys typically used for car body. 2.2.1 Aluminium Manganese Alloys 3xxx This series of alloys is non heat-treatable. The addition of approximately 1% manganese increases the strength by approximately 10 15% compared with 1200, without any major loss in ductility. This non-heat treatable alloy generally finds a wide application where greater strength is required without any major loss in corrosion. The addition of manganese to the chemical composition creates phases like (Mn,Fe)Al6 or (Mn,Fe)3SiAl12 that can be revealed by a solution of 10% of phosphoric acid. The grain structure obtained by work hardening or by annealing is usually revealed by anodisation. (8) 3103 is typically used for car body in the automobile industry. The composition of 3103 alluminium is 0.7% Fe, 1.5% Mn and some others. 2.2.2 Aluminium Magnesium Alloys 5xxx This series of alloys is non heat-treatable and exhibits the best combination of high strength with resistance to corrosion. This series also exhibits good weldability but when the Mg level exceed 3% there is a tendency for stress corrosion resistance to be reduced, dependent on the temper used and temperature of operation. (1) Magnesium is largely soluble in aluminum compared to the other elements, but the content in excess can appear as eutectic Mg2Al3. After cold rolling and annealing they can be found at the grain boundaries or after cold working they can precipitate on deformation bands. In both cases the structure can be revealed by an etching of 10% H3PO4. At the same time as Cr is a frequent additive in this series, Cr2Mg3Al18 may appear as a fine dispersoid. (8) 5182 can be used as car body panel. The composition of 5182 alluminium is 4.1% Mg, 0.4% Mn and some others. 2.2.3 Aluminium Magnesium Silicon Alloys 6xxx This group of heat-treatable alloys uses a combination of magnesium and silicon (magnesium Silicide) to render it heat-treatable. These alloys find their greatest strength, combined with good corrosion resistance, ease of formability and excellent ability to be anodised. This family takes the main advantages from the strengthening due to the precipitation of Mg2Si. So the etching will reveal the iron rich phases like Fe3SiAl12, Fe2Si2Al9 that are insoluble and the coarse precipitates or the excess soluble precipitates (0.5%HF). (8) Typical alloys 6009 in this group are used for car bodies. The composition of 6009 aluminium is Si 1.1%, Mg 0.6 %, Mn 0.4% and some others. 3 Study of competition between steel and Al Automobiles today are over 63% iron and steel by weight. (10) With rising energy and environmental concerns, as well as increases the performance of the car, vehicle light-weighting continues to be a prominent concern for vehicle manufacturers. At the present, more and more aluminium alloys are introduced to automobile industry because the aluminium alloys can normally meet the requirement but is only half weight of steel. However, both the traditional steel car and aluminium have their advantages or disadvantages on aspects of manufacturing, safety, repairability, cost, recyclability, and environmental protection. 3.1 Manufacturing Aluminium parts can be more complicated in their design because the high number of design solutions likes the castings available in nearly any shape. One casting can replace a complex part consisting of several steel panels. Consequently a reduction of parts up to 50% is feasible. (1) This again makes design, construction and production easier as fewer parts need to be dealt with in any stage of the design and manufacturing process. Aluminium car body has fewer parts lead to fewer tools and fixtures, which makes manufacturing easily and therefore saving working spaces and expenses. Because the sheets can tear easily, low elongation and yield limits of aluminium alloys make it difficult for stamping. This has to be taken into account when designing and building car bodies. Also a higher resilience of the sheets causes difficulties in keeping the tolerances during stamping for individual parts and therefore for the whole car body. (11) Furthermore, it is difficult to keep the body tolerances after welding processes since aluminium extrusions and cast sections behave unpredictably when subjected to uneven heat influence. The heat expansion of aluminium is higher than steel, so all fixtures need to be built more solidly and stable to cope with the higher forces. Extensive pickle treatment is necessary to create a weldable surface for aluminium car body. Also the finish of the surface for the paint shop is costly and requires a lot of time and knowledge since the sheets tend to get scratched more easily than equivalent steel panels and the surface of the sheets is liable to form waves. (12) The 6xxx series of aluminium alloys which has been used a lot for the car body requires heat treatment to achieve the demanded strength. The drying process in the paint shop is not sufficient as the conventional temperatures are not high enough. Hence, an additional heat treatment line needs to be installed to heat the car bodies up to 210Â °C for 30 min to harden the aluminium alloys. (13) This cannot be done in advance of manufacturing as it would influence the welding processes negatively. When using aluminium alloy as car body material, contact corrosion plays a much more crucial role as steel accelerates the corrosion of aluminium than using steel body. So that screws or other parts made of steel need to be coated. Otherwise holes in the car body are unavoidable when exposed to moisture. (7) 3.2 Repairability and safety aspects Nowadays, Crash tests have aroused the publics attention since occupant safety is a feature that is receiving considerable public attention. Automobile companies even promote car safety as a leading aspect in their advertising campaigns. Additionally, insurance companies set great store by repairability of cars as they cause a significant part of their costs. In some countries the expenditure per car for repairing certain types of damage is assessed and taken into account when the car is being classified for insurance. (15) In approximately 5% of all accidents the frame structure of a car is damaged. (2) This can be crucial if casting parts or extrusions are concerned as they cannot be reformed properly. They need to be replaced in sections or as a whole dependent on the severity of the accident. Cast aluminium sections especially are liable to develop cracks and consequently need to be examined carefully. Additionally, a completely different approach to repairing damage forces dealers to train their mechanics in the appropriate techniques. In particular aluminium shielded arc welding requires accuracy, practice and the appropriate equipment but not steel. This becomes a problem especially for small dealers as they cannot afford the necessary equipment or staff. (12) Also, tools must not be mixed up with steel tools to avoid corrosion caused by steel particles in the aluminium panels. A separate set of tools for aluminium is mandatory to fully avoid these effects. (14) However, the properties of aluminium offer several advantages to steel. Tubular aluminium sections crumple in the ideal way when subjected to impacts. They develop a crumple pattern that can absorb more energy than equivalent steel elements. Consequently with half the weight of steel an aluminium structural member provides the same safety. (15) 3.3 Cost It is obvious that aluminium is more expensive to manufacture than steel. The costs of a sophisticated aluminium car body are many times larger than of an ordinary steel body. This can be especially crucial when being applied to small cars as the margin there is lower than at luxury cars. Higher material costs, a more sophisticated handling of aluminium parts in comparison to steel and some alloys need heat treatment to achieve the required strength, are the main drawbacks. (9) However, the use of aluminium causes lower investments for tooling due to the fact that stamped steel parts are replaced by extrusions which cause costs only a fraction of the costs required to manufacture stamping tools. This is especially interesting for low volume series as the tooling costs here have a relatively high influence on the unit costs. Additionally, punch riveting and clinching consume less energy than spot welding and will cause lower energy costs. But the development of high volume technology for welding, riveting and bonding is a crucial issue that has kept car manufacturers from producing all-aluminium car bodies as it is accompanied by high initial investment for research, development and design. (15) 3.4 Recyclability Recycling is likely to become more important in the future as governments force industry to design fully recyclable products just as is an increasing customer awareness in terms of environmental protection and hence a growing demand for eco-friendly products. To preserve the quality of the recycled material the different alloys must not be mixed up. This is especially crucial for the production of extrusions and sheets out of recycling aluminium alloys as they have lower tolerance levels of impurities than steel. Additionally, they can only be recovered if they are not mixed with cast parts. (6) Therefore, joined aluminium alloys panels with different alloys cause problems. Also panels that are joined with steel parts like rivets make recycling problematic since steel parts need to be removed to keep the number of foreign substances low. (6) This becomes more difficult as aluminium cannot be magnetically separated from other wastes. In order to recycle aluminium only a fraction of the original energy consumption is needed, even less than for recycling steel. 3.5 Environmental protection The environmental issues of different materials can be assessed by a comparison of the energy household of an aluminium and steel-made car during production and over their whole lives. Only having regard to all processes that cause energy consumption during production and operating life can an accurate result be given of the eco-friendliness of a car. It includes material cycles and the amounts of energy needed to produce and maintain a car during operating life time, including fuel. (15) If primary material is used, aluminium starts with a drawback of an additional energy consumption during production. Compared with steel, far higher amounts of energy are needed to produce lightweight metals like aluminium. For illustration, a car could achieve a weight reduction of 20 kg by the intensive use of aluminium alloys body other than the steel one. The additional energy consumed could be compensated after 3500 miles. After having covered this distance, the energy comparison works in favour of aluminium. A further comparison can be made in terms of carbon dioxide emissions. If primary aluminium is used it takes 60000 miles until the lighter aluminium auto has compensated the higher CO2 emission during production. However, when the proportion of recycled, secondary aluminium exceeds 75% the CO2 emission household is positive for aluminium from the first instance. (1) 4 Summary Considering the energy and environmental issues, using light weight metal for car bodies will be the trends in the near future. However, the traditional steel products still have the advantage of price and easy for manufacturing. Apart from luxuries cars already using light metal bodies, steel car bodies still take a large part of auto body market for it cheaper price and relatively better mechanical properties.

Enders Shadow or Enders Game :: Free Essay Writer

Ender's Shadow or Ender's Game Journal - Enders Shadow Entry 1 In this story there is an alien race called the buggers, they have attacked earth before and now the I.F. (International Fleet) is training the younger generation to be commanders of the next fleet. The main character in Enders Shadow is Bean. He lives on the streets of Rotterdam, in the allies and under steps. Like many other children living on the streets, it is very sparse to find food. Most survive by the leftovers they find in the trash. Bean, being the smallest of the children was the skinniest of them all. He was extremely small. He was on his last few days of life and was so weak he gave up on finding food. That very day a crew leader named Poke (crews were a group of children that shared the food that they found and they had crew leaders) gave Bean 7 peanuts and she asked for his name. But he said he hadn’t received a name, so they called him Bean. There were food shelters that gave food out every morning but crews with young children couldn’t get in because of the older children that were bullies. And most of the time bullies would come and take food from the crews instead of beating them up. Bean had a plan to threaten one bully to protect the crew and I n return he would be allowed to live. They choose to pick the bully named Achilles because he was born with a bad leg and he needed the crew for his safety. They jumped Achilles and held a rock over his head and told him their plan and he agreed to go along with it but Bean told Poke to kill him as and example to the other bullies, but Achilles was smart and he persuaded them to let him be there protector. Entry 2 Achilles made a plan to get the children into the kitchens. When the bullies started lining up for the kitchen Achilles sent one of the crewmembers named Sergeant to the second place in the line budding in front of the meanest bully. The bully shoved the kid into the ground. Achilles came up to the bully and asked him why he pushed Sergeant into the bully in the front. Achilles explained how he was just saving his place in line, until he pushed him into his friend.

The Immune System Essay -- essays research papers

The Immune System   Ã‚  Ã‚  Ã‚  Ã‚  The immune system is a group of cells, molecules, and tissues that help defend the body against diseases and other harmful invaders. The immune system provides protection against a variety of potentially damaging substances that can invade the body. These substances include disease-causing organisms, such as bacteria, fungi, parasites, and viruses. The body's ability to resist these invaders is called immunity. A key feature of the immune system is its ability to destroy foreign invaders while leaving the body's own healthy tissues alone. Sometimes, however, the immune system attacks and damages these healthy tissues. This reaction is called an autoimmune response or autoimmunity.   Ã‚  Ã‚  Ã‚  Ã‚  The immune system is composed of many parts that work together to fight infections when pathogens or poisons invade the human body. Pathogens are disease-causing organisms such as bacteria and viruses. The immune system reacts to foreign substances through a series of steps know as the immune response. Any agent perceived as foreign by a body's immune system is called an antigen. Several types of cells may be involved in the immune response to antigens.   Ã‚  Ã‚  Ã‚  Ã‚  When an antigen enters the body, it may be partly neutralized by components of the innate immune system. It may be attacked by phagocytes or by performed antibodies that act together with the complement system. The human immune system cont...

Examine Two Evolutionary Explanations of Behaviour Essay

Charles Darwin’s theory of evolution puts forward a statement, ‘Survival of the fittest’. This is widely considered true, but in reality truth is a slight variation of this, more commonly known as natural selection. The survivors are the ones who adapt best to their environment and are then able to reproduce. This means that there genes carry on through the generations and we gradually see the preferred characteristics for survival become more common. Over time the human race will become more and more adapted for survival on earth and this process is called evolution. Psychologists look at the behavioural aspects of people in order to work out whether the behaviour of humans has been determined through evolution. They have done this by studying our mechanism determining levels of disgust and the way we prefer one food or type of food over another food, e.g. taste. Our way of determining what is ‘disgusting’ is really a way of stopping us from touching or coming into contact with things that would be harmful to us. This is because these things are supposed to impede our ability to survive. Therefore, humans have adapted so that we are disgusted by these objects. In 2006 Fessler conducted a study on pregnant women who were in their first trimester of their pregnancy and studied their nausea in reaction to certain samples. Fessler hypothesised that these pregnant women would have a higher level of disgust because of their pregnancy. In the first trimester of pregnancy, the immune system of the mother is suppressed so that the foreign body (the baby) growing their womb is safer. Therefore, to keep the women safer, the body develops a heightened sense of disgust to protect itself. Fessler conducted his research on 496 participants (Ps), pregnant women, who were aged 18-50, but were at different points in their pregnancies. This was in order to separate the results and compare the results of women in their first trimester to those of women in their second or third trimestres. All of these women had had normal pregnancies thus far and were considered healthy. He gave each of the women 32 scenarios and asked the women to rate the scenarios by level of disgust. Fessler found that women in their first trimester of pregnancy had a higher sense of disgust than those in their second or third trimesters. This supported Fessler’s hypothesis. Therefore, he concluded that the heightened sense of disgust was advantageous, because it allowed our ancestors to survive for much longer and also allowed their genes, which helped them to surviv, to pass to their offspring. The results also show that there was a diminishing level of disease threat when women are pregnant, because there is not as much of a chance that women will become ill from food, because they will be disgusted by these foods. Therefore, the will be more picky about food. This proves the fact that their disgust mechanism has over-compensated, because the immune system is being suppressed. This study uses a large sample of 496 women. Therefore, the study has population validity. As a result, we can apply the researcher’s findings to a large part of society. Furthermore, the study has cultural validity, because of its large sample. Therefore, it can be applied to people who are from vastly different backgrounds. Lastly, Fessler had a control group to compare results to. This was a group that contained women who were sick in their first trimester and women who were not. The fact that Fessler had a control group makes the results much more reliable. Consequently, we can say that these results are both reliable and valid. On the other hand, the research has many problems with it. One of which is that there are too many scenarios to rate for disgust. Therefore, the Ps may have become de-sensitised by the end of the scenarios or may have felt more disgusted. Furthermore, these results may not reliable. To obtain more reliable results, Fessler should have only used 15-20 scenarios, this leaves him with enough data to complete his research, but is less likely to affect the P. The second problem is that there are demand characteristics. This means that Ps might change their results to help the researchers to find what they want, or might purposefully go differently in order to screw up the results. This means that we cannot rely on the results. Lastly, we do not know the rating scale he used. A scale from 1-an odd number would not be useful because Ps are able to sit on the fence. Therefore, the best scale would be one which ranges from 1-4. In another experiment, 77000 Ps were studied by Curtis et al. (2004). They were studied to see whether there were patterns in people’s disgust responses. These Ps were from 165 different countries. Curtis made all of the participants take a 20 scenario survey like Fessler’s survey. There were seven pairs of photos that looked like its paired photo, but one was shown as an infectious substance. Curtis et al found that the subtstances which would harm humans the most were the substances that were rated as the most disgusting by the Ps. The researchers also found that levels of disgust decreased with age and that women generally had much higher levels of disgust than men. This supports the concept that Fessler supported. That disgust is a way of protecting the unborn child when the immune system is being suppressed. This study has population validity, because it has an extremely large sample (77000 Ps). Therefore, we can apply this to most sectors of society. It also has cultural vailidty, because the Ps are from 165 different countries. This means that we can apply the findings to people from all over the world. Lastly, the test is not too long for it is only 20 scenarios long. This means that the P is unlikely to become de-sensitised or become too disgusted. As a result the research is much more reliable. However, this study doesn’t have ecological validity, because the Ps are looking at pictures on a screen instead of the actual object. This means that disgust may be influenced by other senses like smell and hearing. An improvement because of this may be to actually show the Ps the samples as an object in front of them. Psychologists have also looked to explain other behaviours like what foods we like. For example, as humans, most of us like to eat sweeter foods like fruit. Â  In 1928 Davis investigated the eating behaviour of infants and young children in a paediatric unit. They did thi9s by monitoring the foods that the children chose.Davis found that have ‘an innate regulatory mechanism and are able to select a healthy diet. Furthermore, they tended to choose sweet or salty food while avoiding foods that are bitter. Davis concluded that the preference for sweet food could be because our ancestors needed to eat sweeter, high fructose and glucose foods like fruit, which contain the calories need for energy. Also the preference for salty foods may have been our ancestors preference for meat in their diet. This was for a good source of protein, for growth. The natural avoidance of bitter foods would have helped ancestors protect themselves from eating poisonous foods. Nowadays our preference for sweet foods is satisfied by high-calorie products such as sweets and fizzy-drinks. This research has ecological validity, because the choices of the children were only monitored by the researchers and weren’t forced. This means that the results are valid for the children in this environment. However, this experiment has many problems. One of which is that it doesn’t have population validity. This means that the results cannot be generalised to most of the population. The research only includes one paediatric unit. This means that the study doesn’t have cultural validity. As a result, we cannot generalise the findings of the study to lots of countries or areas of society. To achieve cultural validity, they should’ve used various paediatric units across the world. Another study looking into the food preferences of children was Desor’s study in 1973. Desor studied the facial expressions and sucking behaviour of new born babies. Desor ended up studying 83 different children from the ages of 4-7 (42 girls and 41 boys). The study was similar to Davis’ study, but the children were studied in a classified room after the children had acclimatised to their surroundings. They found that that the children preferred sweet-tasting substances which challenges what Davis’s study had stated (children has an innate regulatory mechanism making them choose a healthy diet). This study doesn’t have population validity, because the sample is not big enough to generalise the findings of the research to the general population. They should have advertised across the country, resulting in much more data. It also doesn’t have cultural validity, because they only got Ps from the local area. This is known because they advertised for Ps in local newspapers. Therefore, the findings cannot be applied to people from other cultures. In conclusion, there is a way to explain food preferences as described in studies. For example, humans prefer sweet foods because of ancestors need for food with high levels of fructose or glucose like fruit (according to David 1928).