Evaluation of Bretton Woods Institution’s Influence on the Sovereign Decision Making Essay

Truly our global economy works in complexity as various collaborations and interrelationships happens between countries around the globe. Because of the interaction of different economies, Bretton Woods Institutions were established to guide those developing countries towards the attainment of impressive economic growth through the assistance of developed countries. Two of the major organizations under the Bretton Wood Institutions would be the World Bank and International Monetary Fund which provides research and financial services to developing countries to boost the economic activity of developing countries. Despite of the said gains that World Bank and International Monetary Fund offers to developing countries, a lot of debates concerning the real effects of such â€Å"intermediation† of WB and IMF happening on various parts of the globe. In this regard, the main question that this paper will about to answer would be: what are the effects of Bretton Woods Institutions programs on the sovereignty of developing countries and would there be really benefits that can be derived by developing countries on such existence of international institutions in the long run? These are some of the questions that we will uncover by the end of this paper. One of the main programs of World Bank and IMF for the developing countries would be to lend funds that can be used for economic development such as building of various infrastructures like roads and bridge that are essential to attract more foreign investors (Fischer et al 2003: 4). Aside from this, both of the identified international institutions provides research assistance as to how to deal with various economic problems such as poverty, high inflation and unemployment rate as well as stabilizing financial sector of the economy. But the only problem with IMF and WB would be their policy-conditional lending wherein they demand reforms on various economic policies of developing countries like lower tariff rate for United States or higher tax discount on foreign investors from developed countries in exchange for funds. Therefore, to some extent, IMF and WB, influences the economic policies of developing countries by requiring the latter to comply first on IMF and WB’s policy reforms before granting those financial aids. Since it is the government that makes economic policies, sovereignty is now at stake every time developing countries borrow money to MF and WB since the government becomes powerless from the demands of IMF and WB, and just let these international institutions to change whatever economic policies that is currently being implemented. For the past two decades, IMF and WB have been able to influence every developing country around the globe. Lending money serves as the powerful tool of IMF and WB in successfully penetrating the sovereignty of a given developing country in exchange for funding. In the short run perspective, every one would agree that IMF and WB are of great help for developing countries. But in the long run, due to their interventions on economic policies of developing countries, there is a tendency that the policy-conditional lending of IMF and WB would not fit to the nature of economic activities a certain country has thereby will only cause instability in the next coming years. In this regard, it is already clear that the policy-condition lending of IMF and WB would only provide short lived benefits for the economy of developing countries since negative effects of the said intervention would offset all those benefits. It would be better if IMF and WB would minimize its interventions on economic policies of developing countries to give room for the latter to have sustainable economic development.

Aristotle and Oedipus essays

Aristotle and Oedipus essays Oedipus is a prime example of a tragidy, according to Aristotles definition in the poetics. Aristotles Poetics is considered the first work of literary criticism in our tradition. The couple of pages in the book mainly describe tragedy from Aristotles point of view. He defines tragedy as being an imitation of an action that is a whole and complete in itself and of a certain magnitude. Aristotle also points out terms such as catharsis, which can be said that is the purification of ones soul. He argues in his Poetics that catharsis is achieved through emotions of pity or fear, which is created in the audience as they witness the tragedy of a character who suffers unjustly, but is not entirely innocent. Then he moves on to describing the main elements of tragedy. Such elements are: plot, character, language, thought, spectacle, and melody. Then he classifies these in three parts, the media, the manner and the objects. The language and melody constitute the media, in which they effect the imitation. Then there is the spectacle, which is the manner, and the remaining three, the plot, character and thought are the objects that are imitated. Aristotle considers the plot to be the most important of these elements. He describes the plot as not being a unity revolving around one man. Instead, he states that many things happen to one man, which may not always go together, to form a unity. At the same time, he says that among the actions that a character performs there are many that may be irrelevant to one another, but yet they form a unified action. Aristotle continues depicting the plot categorizing it in two manners: simple and complex. In a simple plot, a change of fortune takes place without a reversal or recognition. In contrast, in a complex plot, the change of fortune involves recognition or a reversal or both. T...

Womanhouse, CalArts 1970s Feminist Art Collaboration

Womanhouse, CalArts 1970s Feminist Art Collaboration Womanhouse was an art experiment that addressed the experiences of women. Twenty-one art students refurbished an abandoned house in Los Angeles and turned it into a provocative 1972 exhibit. Womanhouse received national media attention and introduced the public to the idea of Feminist Art. The students came from the new Feminist Art Program at the California Institute of the Arts (CalArts). They were led by Judy Chicago  and Miriam Schapiro. Paula Harper, an art historian who also taught at CalArts, suggested the idea to create a collaborative art installation in a house. The purpose was more than just to showcase womens art or art about women.   The purpose, according to Linda Nochlins bok on Miriam Schapiro, to  help women  restructure their personalities to be more consistent with their desires to be  artists and to help them build their art making out of their experiences as  women. One inspiration was Judy Chicagos discovery that a womans building had been part of the 1893 Worlds Columbian Exposition in Chicago. The building was designed by a woman architect, and many art works, including one by Mary Cassatt, were featured there. The House The abandoned house in the urban Hollywood area was condemned by the city of Los Angeles. The Womanhouse artists were able to postpone the destruction until after their project. The students devoted enormous amounts of their time in late 1971 to refurbishing the house, which had broken windows and no heat. They struggled with repairs, construction, tools, and cleaning out the rooms that would later house their art exhibits. The Art Exhibits Womanhouse was opened to the public in January and February of 1972, gaining a national audience. Each area of the house featured a different work of art.   â€Å"Bridal Staircase,† by Kathy Huberland, showed a mannequin bride on the stairs. Her long bridal train led to the kitchen and became progressively grayer and dingier along its length. One of the most famous and memorable exhibits was Judy Chicago’s â€Å"Menstruation Bathroom.† The display was a white bathroom with a shelf of feminine hygiene products in boxes and a trash can full of used feminine hygiene products, the red blood striking against the white background. Judy Chicago said that however women felt about their own menstruation would be how they felt seeing it depicted in front of them. Performance Art There were also performance art pieces at Womanhouse, initially done for an all-female audience and later opened to male audiences as well. One exploration of men’s and women’s roles featured actors playing â€Å"He† and â€Å"She,† who were visually depicted as male and female genitalia. In â€Å"Birth Trilogy,† performers crawled through a â€Å"birth canal† tunnel made of the legs of other women. The piece was compared to a Wiccan ceremony. The Womanhouse Group Dynamic The Cal-Arts students were guided by Judy Chicago and Miriam Schapiro to use consciousness-raising and self-examination as processes that preceded making the art. Although it was a collaborative space, there were disagreements about power and leadership within the group. Some of the students, who also had to work at their paying jobs before coming to labor at the abandoned house, thought that Womanhouse required too much of their devotion and left them no time for anything else. Judy Chicago and Miriam Schapiro themselves disagreed about how closely Womanhouse should be tied to the CalArts program. Judy Chicago said things were good and positive when they were at Womanhouse, but became negative once they were back on the CalArts campus, in the male-dominated art institution. Filmmaker Johanna   Demetrakas made a documentary film called Womanhouse about the feminist art event. The 1974 film includes the performance art pieces as well as reflections by the participants. The Women The two primary movers behind Womanhouse were Judy Chicago and Miriam Shapiro. Judy Chicago, who changed her name to that from Judy Gerowitz in 1970, was one of the major figures in Womanhouse. She was in California to establish a Feminist Art Program at Fresno State College. Her husband, Lloyd Hamrol, was also teaching at Cal Arts. Miriam Shapiro was in California at that time, having originally moved to California when her husband Paul Brach was appointed dean at Cal Arts. He accepted the appointment only if Shapiro would also become a faculty member.   She brought her interest in feminism to the project. A few of the other women involved included: Faith WildingBeth BachenheimerKaren LeCocqRobbin Schiff Edited and updated with content added​ by Jone Johnson Lewis.

Industrial Revolution Essay Example | Topics and Well Written Essays - 250 words - 1

Industrial Revolution - Essay Example d politics, thereby stimulating varied other disempowered and marginalized sections of the society to strive for empowerment and a fair share in the national income. Capital emerged as the pivotal factor of production. This led to a greater polarization of opinion on both sides that are the labor and the capitalists, thereby both sections getting more organized and politicized. One negative thing about Industrial Revolution was that it envisaged earth as an external resource to serve as a fodder for the industrial engine of growth. In the long run it not only resulted in an irreversible depletion of natural resources and the commensurate pollution, but led to the contemporary challenges like global warming. There is no denying the fact that the map set by Industrial Revolution is not absolutely relevant in the current times marked by the emergence of new priorities like sustainable development and corporate social

Credit Risk Management Essay Example | Topics and Well Written Essays - 2000 words

Credit Risk Management - Essay Example In other words, the bank has to incorporate technological processes in the identification of risk. Credit risk management must start from a particular point and this is determination of where the problem is. (Reserve bank of Vanuatu, 2007) No effective solution can be worked out if the bank does not understand the full magnitude of its problems. Additionally, banks that fail to understand the dynamics involved in counterparty risks are also likely to fail in managing that risk. Technology is also essential in the measurement of risk because through the latter, the bank can have standardised ways of dealing with it. Besides these, robust technology is also critical in the actual process of managing the risk. (Damiano and Massimo, 2006) The latter facts may seem quite basic to the bank, however, a word of caution is necessary when dealing with this issue. Because of forces of globalisation and the technology wave, many banks and financial instructions are merely rushing to the latest IT products without due consideration of their personal needs. This is the point at which these financial institutions go wrong; the most sophisticated form of IT can be worthless if it does not meet the needs of the bank. Consequently, there should be more emphasis on the process rather than the product in this regard. If all a bank needs is a simple IT tool to meet their needs, then they should opt for only what they need. In certain cases less is more; credit risk management ought to take precedence over other systems that are required to implement them. Numerous companies tend to operate from the wrong side thus making it increasingly difficult to proceed with one's choices. A research conducted by a certain investment bank (Lepus) about the importance of information technology in implementing effective credit risk management found out the following: Importance of technology in credit risk management 0% 5% 10% 15% 20% 25% 30% 35% 40% Just a tool Enhances efficiency and effectiveness Eradicates manual processes Promotes data transparency Smoothens Global credit risk Active management of portfolio Source: Lepus Investment Bank (2007): Effective risk management, available at http://www.sas.com/ accessed on 27th November As it can be seen above, the most important function among these bankers is the management and development of a bank's portfolio. Information technology is therefore a vital tool in effecting strategies for effective risk management. Aside from technology, a bank needs to have a comprehensive strategic policy for achievement of effective credit risk management. It should be noted that this forms the backbone of successful credit risk management. The principles and guidelines provide a background against which banks can operate in a sound environment. These policies serve as directional pointers to financial institutions because they are a set of rules that can be applied in a series of credit situations facing them. (Brigo and Pallavicini, 2007) The bank under study needs to put in mind the fact that those companies that have failed in their credit risk management endeavours have done so because of a lack of commitment to their policies and procedures. Having a set of rules that have been smartly laid out by a series of credit risk management experts is just one side of the story. The other side is

Statistics in the workplace Essay Example | Topics and Well Written Essays - 750 words

Statistics in the workplace - Essay Example Health statistics gives information on the health matters of people. This means that every person is part of a health statistic. To get knowledge, an organization first gathers data, these data is processed into facts and figures which are transformed into information. Statistics has several other uses such as making decision on the relevant staffing needs of the hospital facility in relation to information or data collected frequency or number of patients a hospital has per period of time. Some of the many ways in which statistics can be used in rehabilitation health facility include: to carry out surveys on patient satisfaction or employee satisfaction, to carry out tests or experiments on new procedures just to mention but a few. There are various branches of statistics, the two main branches are; descriptive and inferential statistics. Descriptive statistics Descriptive statistics is a branch of statistics that describes data that has been gathered revealing the trends and patter ns of the information. Descriptive statistics illustrates how data is dispersed but does not test any hypothesis so as to form a conclusion on the basis of that data (Bennett, Briggs, Triola, 2009). In healthcare, descriptive statistics is used for various purposes. ... The patients who consent to the trial will undergo close monitoring during the study through close observation and evaluation. The results will be based on specifics such as the degree of side effects, rate of recovery and they are not charged for the process. Descriptive statistics basically uses aspects such as means of central tendency and dispersions these are mean and standard deviation respectively. In this example the mean will be used to give the overall impact of the procedure towards rehabilitation while standard deviation might be used to show how stable or unstable the drug may be. Stability simply means the uniformity in the way patients react to the procedure, therapy or drug. Inferential statistics is simply a method through which conclusions about an aspect of a population is drawn from a sample. A sample is a finite subset of a population. This is the procedure of selecting and using a sample statistic to draw conclusions about the population parameters and eventuall y the population. It is used when we have access to a sample but not the population. Statistical inference uses two methods namely; point estimate and hypothesis testing. The estimation method is usually used to inferences where information about a population is in the given sample. There are two kinds of estimates which are point estimate and interval estimate. The estimates are used to make inference on the population parameters. An example of point-estimates is the mean weight of patients in the hospital while an interval estimate is the range within which we expect the mean of a population to fall at some level of confidence say 95%. Hypothesis testing on the other hand is the

History and overview: Catalytic converter

History and overview: Catalytic converter A catalytic converter (colloquially, cat or catcon) is a device used to decrease the toxicity of emissions from an internal combustion engine. A catalytic converter works by using a catalyst to stimulate a chemical reaction in which toxic by-products of combustion are converted to less-toxic substances.First widely introduced on series-production automobiles in the U.S. market for the 1975 model year to comply with tightening EPA regulations on auto exhaust, catalytic converters are still most commonly used in motor vehicle exhaust systems. Catalytic converters are also used on generator sets, forklifts, mining equipment, trucks, buses, trains, airplanes and other engine-equipped machines. History The catalytic converter was invented by Eugene Houdry, a French mechanical engineer and expert in catalytic oil refining[1] who lived in the United States. Around 1950, when the results of early studies of smog in Los Angeles were published, Houdry became concerned about the role of automobile exhaust in air pollution and founded a special company, Oxy-Catalyst, to develop catalytic converters for gasoline engines an idea ahead of its time for which he was awarded a patent (US2742437). Widespread adoption had to wait until the extremely effective anti-knock agent tetraHYPERLINK http://en.wikipedia.org/wiki/Tetra-ethyl_lead-HYPERLINK http://en.wikipedia.org/wiki/Tetra-ethyl_leadethylHYPERLINK http://en.wikipedia.org/wiki/Tetra-ethyl_lead HYPERLINK http://en.wikipedia.org/wiki/Tetra-ethyl_leadlead was eliminated from most gasoline over environmental concerns, as the agent would foul the converter by forming a coating on the catalysts surface, effectively disabling it.[2] The catalytic converter was further developed by JohnHYPERLINK http://en.wikipedia.org/wiki/John_J._Mooney J. HYPERLINK http://en.wikipedia.org/wiki/John_J._MooneyMooney and CarlHYPERLINK http://en.wikipedia.org/wiki/Carl_D._Keith D. HYPERLINK http://en.wikipedia.org/wiki/Carl_D._KeithKeith at the EngelhardHYPERLINK http://en.wikipedia.org/wiki/Engelhard_Corporation HYPERLINK http://en.wikipedia.org/wiki/Engelhard_CorporationCorporation,[3] creating the first production catalytic converter . Metal-core converter Ceramic-core converter The catalytic converter consists of several components: The core, or substrate. The core is often a ceramic honeycomb in modern catalytic converters, but stainlessHYPERLINK http://en.wikipedia.org/wiki/Stainless_steel HYPERLINK http://en.wikipedia.org/wiki/Stainless_steelsteel foil honeycombs are also used. The honey-comb surface increases the amount of surface area available to support the catalyst, and therefore is often called a catalystHYPERLINK http://en.wikipedia.org/wiki/Catalyst_support HYPERLINK http://en.wikipedia.org/wiki/Catalyst_supportsupport. The ceramic substrate was invented by RodneyHYPERLINK http://en.wikipedia.org/wiki/Rodney_Bagley HYPERLINK http://en.wikipedia.org/wiki/Rodney_BagleyBagley, IrwinHYPERLINK http://en.wikipedia.org/wiki/Irwin_Lachman HYPERLINK http://en.wikipedia.org/wiki/Irwin_LachmanLachman and RonaldHYPERLINK http://en.wikipedia.org/w/index.php?title=Ronald_Lewis_(scientist)action=editredlink=1 HYPERLINK http://en.wikipedia.org/w/index.php?title=Ronald_Lewis_(scientist)action=editredlink=1Lewis at Cor ningHYPERLINK http://en.wikipedia.org/wiki/Corning_Glass HYPERLINK http://en.wikipedia.org/wiki/Corning_GlassGlass, for which they were inducted into the NationalHYPERLINK http://en.wikipedia.org/wiki/National_Inventors_Hall_of_Fame HYPERLINK http://en.wikipedia.org/wiki/National_Inventors_Hall_of_FameInventorsHYPERLINK http://en.wikipedia.org/wiki/National_Inventors_Hall_of_Fame HYPERLINK http://en.wikipedia.org/wiki/National_Inventors_Hall_of_FameHallHYPERLINK http://en.wikipedia.org/wiki/National_Inventors_Hall_of_Fame of HYPERLINK http://en.wikipedia.org/wiki/National_Inventors_Hall_of_FameFame in 2002. The washcoat. A washcoat is used to make converters more efficient, often as a mixture of silica and alumina. The washcoat, when added to the core, forms a rough, irregular surface, which has a far greater surface area than the flat core surfaces do, which then gives the converter core a larger surface area, and therefore more places for active precious metal sites. The catalyst is added to the washcoat (in suspension) before being applied to the core. The catalyst itself is most often a precious metal. Platinum is the most active catalyst and is widely used. It is not suitable for all applications, however, because of unwanted additional reactions and/or cost. Palladium and rhodium are two other precious metals used. Platinum and rhodium are used as a reduction catalyst, while platinum and palladium are used as an oxidization catalyst. Cerium, iron, manganese and nickel are also used, although each has its own limitations. Nickel is not legal for use in the European Union (due to reaction with carbon monoxide). Copper can be used everywhere except North America, where its use is illegal due to the formation of dioxin. How Catalytic Converters Work James L. Amos/National Geographic/Getty Images A large pile of platinum lined catalytic converters. See more green living pictures. There are millions of cars on the road in the United States, and each one is a source of air pollution. Especially in large cities, the amount of pollution that all the cars produce together can create big problems. To solve those problems, cities, states and the federal government create clean-air laws that restrict the amount of pollution that cars can produce. Over the years, automakers have made many refinements to car engines and fuel systems to keep up with these laws. One of these changes came about in 1975 with an interesting device called a catalytic converter. The job of the catalytic converter is to convert harmful pollutants into less harmful emissions before they ever leave the cars ­ exhaust system. Catalytic converters are amazingly simple devices, so it is incredible to see how big an impact they have. In this article, you will learn which pollutants are produced by an engine and how a catalytic converter deals with each of these pollutants to help reduce [edit] Types [edit] Two-way A two-way catalytic converter has two simultaneous tasks: Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ 2CO2 Oxidation of unburnt hydrocarbons (unburnt and partially-burnt fuel) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2] O2 à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ xCO2 + (x+1) H2O (a combustion reaction) This type of catalytic converter is widely used on diesel engines to reduce hydrocarbon and carbon monoxide emissions. They were also used on gasoline engines in USA market automobiles until 1981. Due to their inability to control nitrous oxide NOHYPERLINK http://en.wikipedia.org/wiki/NOxx, they were superseded by three-way converters. [edit] Three-way Since 1981, three-way catalytic converters have been used in vehicle emission control systems in North America and many other countries on roadgoing vehicles. A three-way catalytic converter has three simultaneous tasks: Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ xO2 + N2 Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ 2CO2 Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ xCO2 + (x+1)H2O These three reactions occur most efficiently when the catalytic converter receives exhaust from an engine running slightly above the stoichiometric point. This point is between 14.6 and 14.8 parts air to 1 part fuel, by weight, for gasoline. The ratio for LPG, natural gas and ethanol fuels is slightly different, requiring modified fuel system settings when using those fuels. Generally, engines fitted with 3-way catalytic converters are equipped with a computerized closed-loop feedback fuel injection system using one or more oxygen sensors, though early in the deployment of 3-way converters, carburetors equipped for feedback mixture control were used. While a 3-way catalyst can be used in an open-loop system, NOx reduction efficiency is low. Within a narrow fuel/air ratio band surrounding stoichiometry, conversion of all three pollutants is nearly complete. However, outside that band, conversion efficiency falls very rapidly. When there is more oxygen than required, the system is said to be running lean, and the system is in oxidizing condition. In that case, the converters two oxidizing reactions (oxidation of CO and hydrocarbons) are favoured, at the expense of the reduction of NOx. When there is excessive fuel, the engine is running rich; the reduction of NOx is favoured, at the expense of CO and HC oxidation. [edit] Oxygen storage Three-way catalytic converters can store oxygen from the exhaust gas stream, usually when the air fuel ratio goes lean.[5] When insufficient oxygen is available from the exhaust stream, the stored oxygen is released and consumed (see cerium(IV) oxide). This lean-ness occurs either when oxygen derived from NOx reduction is unavailable or certain maneuvers such as hard acceleration enrich the mixture beyond the ability of the converter to supply oxygen. [edit] Unwanted reactions Unwanted reactions can occur in the three-way catalyst, such as the formation of odiferous hydrogen sulfide and ammonia. Formation of each can be limited by modifications to the washcoat and precious metals used. It is difficult to eliminate these byproducts entirely. Sulfur-free or low-sulfur fuels eliminate or reduce hydrogen sulfide. For example, when control of hydrogen sulfide emissions is desired, nickel or manganese is added to the washcoat. Both substances act to block the adsorption of sulfur by the washcoat. Hydrogen sulfide is formed when the washcoat has adsorbed sulfur during a low temperature part of the operating cycle, which is then released during the high temperature part of the cycle and the sulfur combines with HC. [edit] For diesel engines For compression-ignition (i.e., diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. This catalyst uses O2 (oxygen) in the exhaust gas stream to convert CO (carbon monoxide) to CO2 (carbon dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often operate at 90% efficiency, virtually eliminating diesel odor and helping to reduce visible particulates (soot). But they cannot reduce NOx because chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first. To reduce NOx on a compression ignition engine, the chemical composition of the exhaust must first be changed. Two main techniques are used: exhaust gas recirculation (EGR) and selective catalytic reduction (SCR). NOx trapping (with NOx absorbers) is a third method, but as of yet (2010), is not widely used. Diesel engine exhaust contains relatively high levels of particulate matter (soot), consisting in large part of elemental carbon. Catalytic converters cannot clean up elemental carbon, though they do remove up to 90% of the soluble organic fraction[citation needed], so particulates are cleaned up by a soot trap or diesel particulate filter (DPF). In the United States, all on-road heavy-duty vehicles powered by diesel and built after 1 January 2007 must be equipped with a catalytic converter and a diesel particulate filter.[6] Instead of catalysis, a reagent such as ammonia pyrolyzed in situ from urea, is sometimes used to reduce the NOx into nitrogen. One trademark product to do this is AdBlue. [edit] For lean-burn engines For lean burn spark ignition engines, an oxidation catalyst is used in the same manner as in a diesel engine. [edit] Installation Many vehicles have a pre-catalyst located close to the engines exhaust manifold. This unit heats up quickly due to its proximity to the engine, and reduces cold-engine emissions by burning off hydrocarbons from the extra-rich mixture used in a cold engine. Many three-way catalytic converters utilize an air injection tube between the first (NOx reduction) and second (HC and CO oxidation) stages of the converter. This tube is fed by a secondary air injection system. The injected air provides oxygen for the catalysts oxidizing reaction. These systems also sometimes include an upstream air injector to admit oxygen to the exhaust system before it reaches the catalytic converter. This precleans the extra-rich exhaust from a cold engine, and helps bring the catalytic converter quickly up to operating temperature. Some newer systems do not employ air injection. Instead, they provide a constantly varying mixture that quickly and continually cycles between lean and rich to keep the first catalyst (NOx reduction) from becoming oxygen loaded, and to keep the second catalyst (CO oxidization) sufficiently oxygen-saturated. They also utilize several oxygen sensors to monitor the exhaust, at least one before the catalytic converter for each bank of cylinders, and one after the converter. Some systems contain the reduction and oxidation functions separately rather than in a common housing. [edit] Damage [edit] Poisoning Catalyst poisoning occurs when the catalytic converter is exposed to exhaust containing substances that coat the working surfaces, encapsulating the catalyst so that it cannot contact and treat the exhaust. The most notable contaminant is lead, so vehicles equipped with catalytic converters can only be run on unleaded gasoline. Other common catalyst poisons include manganese primarily from the gasoline additive MMT, and silicone which can enter the exhaust stream if the engine has a leak allowing coolant into the combustion chamber. Phosphorus is another catalyst contaminant. Although phosphorus is no longer used in gasoline, it (and zinc, another low-level catalyst contaminant) was until recently widely used in engine oil antiwear additives such as ZDDP. Beginning in 2006, a rapid phaseout of ZDDP in engine oils began.[citation needed] Depending on the contaminant, catalyst poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time. The increased exhaust temperature can sometimes liquefy or sublimate the contaminant, removing it from the catalytic surface. However, removal of lead deposits in this manner is usually not possible due to leads high boiling point. [edit] Meltdown Any condition that causes abnormally high levels of unburned hydrocarbons raw or partially-burnt fuel to reach the converter will tend to significantly elevate its temperature, bringing the risk of a meltdown of the substrate and resultant catalytic deactivation and severe exhaust restriction. Vehicles equipped with OBD-II diagnostic systems are designed to alert the driver of a misfire condition, along with other malfunctions, by means of the Check Engine light on the dashboard. [edit] Regulations This section does not citeany references or sources. Please help improve this articleby adding citations to reliable sources. Unsourced material may be challengedand removed. (March 2009) Emissions regulations vary considerably from jurisdiction to jurisdiction. In North America, most spark ignition engines of over 25 brake horsepower (19 kW) output built after January 1, 2004 are equipped with three-way catalytic converters. In Japan, a similar set of regulations came into effect January 1, 2007, while the European Union has not yet enacted analogous regulations. Most automobile spark ignition engines in North America have been fitted with catalytic converters since the mid-1970s, and the technology used in non-automotive applications is generally based on automotive technology. Regulations for diesel engines are similarly varied, with some jurisdictions focusing on NOx (nitric oxide and nitrogen dioxide) emissions and others focusing on particulate (soot) emissions. The regulatory diversity is challenging for manufacturers of the engine as it may not be economical to design an engine to meet two sets of regulations. Regulations of fuel quality vary across jurisdictions. In North America, Europe, Japan, and Hong Kong, gasoline and diesel fuel are highly regulated, and CNG and LPG are being reviewed for regulation. In most of Asia and Africa, the regulations are often lax in some places sulfur content of the fuel can reach 20,000 parts per million (2%). Any sulfur in the fuel can be oxidized to SO2 (sulfur dioxide) or even SO3 (sulfur trioxide) in the combustion chamber. If sulfur passes over a catalyst, it may be further oxidized in the catalyst, i.e. (SO2 may be further oxidized to SO3). Sulfur oxides are precursors to sulfuric acid, a major component of acid rain. While it is possible to add substances like vanadium to the catalyst wash coat to combat sulfur oxide formation, such addition will reduce the effectiveness of the catalyst. The most effective solution is to further refine fuel at the refinery to produce ultra-low sulfur diesel. Regulations in Japan, Europe, and North America tightly restrict the amount of sulfur permitted in motor fuels. However, the expense of producing such clean fuel make it impractical for use in many developing countries. As a result, cities in these countries with high levels of vehicular traffic suffer from acid rain, which damages stone and woodwork of buildings and damages local ecosystems. [edit] Negative aspects Some early converter designs greatly restricted the flow of exhaust, which negatively affected vehicle performance, driveability, and fuel economy.[7] Because they were used with carburetors incapable of precise fuel/air mixture control, they could overheat and set fire to flammable materials under the car.[8] Removing a modern catalytic converter in new condition will only slightly increase vehicle performance without retuning,[9] but their removal or gutting continues.[7]HYPERLINK http://en.wikipedia.org/wiki/Catalytic_converter#cite_note-9[10] The exhaust section where the converter was may be replaced with a welded-in section of straight pipe, or a flanged section of test pipe legal for off-road use that can then be replaced with a similarly fitted converter-choked section for legal on-road use, or emissions testing.[9] In the US and many other jurisdictions, it is illegal to remove or disable a catalytic converter for any reason other than its immediate replacement[citation need ed]; vehicles without functioning catalytic converters generally fail emission inspections. The aftermarket supplies high-flow converters for vehicles with upgraded engines, or whose owners prefer an exhaust system with larger-than-stock capacity.[11] [edit] Warm-up period Most of the pollution put out by a car occurs during the first five minutes before the catalytic converter has warmed up sufficiently.[12] [edit] Environmental impact Catalytic converters have proven to be reliable and effective in reducing noxious tailpipe emissions. However, they may have some adverse environmental impacts in use: The requirement for a rich burn engine to run at the stoichiometric point means it uses more fuel than a lean burn engine running at a mixture of 20:1 or less. This increases the amount of fossil fuel consumed and the carbon dioxide emissions of the vehicle. However, NOx control on lean burn engines is problematic. Although catalytic converters are effective at removing hydrocarbons and other harmful emissions, they do not solve the fundamental problem created by burning a fossil fuel. In addition to water, the main combustion product in exhaust gas leaving the engine through a catalytic converter or not is carbon dioxide (CO2).[13] Carbon dioxide produced from fossil fuels is one of the greenhouse gases indicated by the Intergovernmental Panel on Climate Change (IPCC) to be a most likely cause of global warming.[14] Additionally, the U.S. Environmental Protection Agency (EPA) has stated catalytic converters are a significant and growing cause of global warming, due to their release of nitrous oxide (N2O), a greenhouse gas over 300 times more potent than carbon dioxide.[15] Catalytic converter production requires palladium or platinum; part of the world supply of these precious metals is produced near the Russian city of Norilsk, where the industry (among others) has caused Norilsk to be added to Time Magazines list of most polluted places.[16] [edit] Theft Due to the external location and the use of valuable precious metals including platinum, palladium, and rhodium, converters are a target for thieves. The problem is especially common among late-model Toyota trucks and SUVs, due to their high ground clearance and easily-removed bolt-on catalytic converters. Welded-in converters are also at risk of theft from SUVs and trucks, as they can be easily removed.[17]HYPERLINK http://en.wikipedia.org/wiki/Catalytic_converter#cite_note-17[18] Theft removal of the converter can often inadvertently damage the cars wiring or fuel line resulting in dangerous consequences. Rises in metal costs in the United States during recent years have led to a large increase in theft incidents of the converter,[19] which can then cost as much as $1000 to replace.[20] [edit] Diagnostics Various jurisdictions now legislate on-board diagnostics to monitor the function and condition of the emissions control system, including the catalytic converter. On-board diagnostic systems take several forms. [edit] Temperature sensors Temperature sensors are used for two purposes. The first is as a warning system, typically on 2-Way catalytic converters such as are still sometimes used on LPG forklifts. The function of the sensor is to warn of catalytic converter temperature above the safe limit of 750  °C (1,380  °F). More recent catalytic converter designs are not as susceptible to temperature damage and can withstand sustained temperatures of 900  °C (1,650  °F).[citation needed] Temperature sensors are also used to monitor catalyst functioning usually two sensors will be fitted, with one before the catalyst and one after to monitor the temperature rise over the catalytic converter core. For every 1% of CO in the exhaust gas stream the exhaust gas temperature will rise by 100 °C.[citation needed] [edit] Oxygen sensors The Oxygen sensor is the basis of the closed loop control system on a spark ignited rich burn engine, however it is also used for diagnostics. In vehicles with OBD II, a second oxygen sensor is fitted after the catalytic converter to monitor the O2 levels. The on-board computer makes comparisons between the readings of the two sensors. If both sensors give the same output, the computer recognizes the catalytic converter is not functioning or removed, and will operate a check engine light and retard engine performance. Simple oxygen sensor simulators have been developed to circumvent this problem by simulating the change across the catalytic converter with plans and pre-assembled devices available on the internet, though these are not legal for on-road use.[21] Similar devices apply an offset to the sensor signals, allowing the engine to run a more fuel economical lean burn that may however damage the engine or the catalytic converter.[22] [edit] NOx sensors NOx sensors are extremely expensive and are generally only used when a compression ignition engine is fitted with a selective catalytic reduction (SCR) converter, or a NOx absorber catalyst in a feedback system. When fitted to an SCR system, there may be one or two sensors. When one sensor is fitted it will be pre-catalyst, when two are fitted the second one will be post catalyst. They are utilized for the same reasons and in the same manner as an oxygen sensor the only difference is the substance being monitored.