Chromium and Nickel in Welding Fumes Essay Example for Free

Chromium and Nickel in weld Fumes EssayChromium and nickel compounds atomic number 18 iodin of the many byproducts of the reaction in the midst of a metals and welding materials. Welders be exposed to these byproducts all throughout their welding puzzle outs. However, too much depiction of a person to these by products may consider to serious wellness problems. In this paper, the disparity of American Welding Society safety facts and other organizations will be discussed. In addition, the ways to control ikon to the express compounds will be discussed. An everywhereview of such effects of nickel and chromium compound fume is listed by the AWS. It is stated that nickel and chromium compound experience argon possible carcinogens to the human system. Health effects of alloys that contain nickel and chromium to welders and users are not yet determined. Possible health effects should be referred to National name of Occupational Safety and Health (NIOSH) and Internationa l Agency for Research on Cancer (IARC) (American Welding Society AWS, 2003). When bingle say that a person is exposed to a certain compound, this means many things. However, in this paper fumes that has concentrations of nickel and chromium compound.The disparity between the organizations will be examined. The American Welding Society (AWS) discussed three things, the immediate effects of exposure to fumes, the chronic or long-term effects of exposure to the fumes and protection against over exposure. In controlling exposure of a welder to nickel and chromium compounds, the AWS suggested a few things. First, welders or persons that are near welding sites should avoid inhaling the fumes. Second, Proper ventilating system and exhausts should be provided to welding sites and arcs to avoid the gases to be near your breathing system.Third, Air samples should be tested for the correct level of compounds in the air if ventilation and exhausts are not decent established in a welding loca tion. Last, minimize the exposure to the tell compounds (American Welding Society AWS, 2003). In contrast to the recommendations of AWS, Nickel Institute has a more detailed recommendation for controlling exposure to fumes with nickel and chromium compounds concentrate. In their recommendation, the level of concentrations of nickel and chromium compounds in fumes should be limited to 0. 05 mg/m3 up to 0. 1 mg/m3.In the recommendation, it is also stated that to control emission of fumes, proper choice of welding do work must be employed. However, choice of welding process is usually determined by the adept and economic factors (Nickel Development Institute NDI, 2001). Overall, safety of welders is still the guardianship that should be given proper handling. The goal of having a good control of the fumes with chromium compounds and nickel concentrations is to eliminate it. If one cannot eliminate it, wherefore one should minimize it. First, proper welding process should be employ ed. Second, welder should work in a proper welding area.This means that the workplace should be fully freshen and has exhausts. Third, proper welder equipments and apparatus should be employ. Fourth, proper welder uniform should be used. This is one of the most important things to be considered. If a welder has a proper uniform, then possible direct damages to the person may be minimized or neglected. Last, routine checks of the work area, equipments, apparatus, and welders should be done. This means that a routine check of the utter things must be done, like checking fume concentration levels, checking welder health, etc, in order to secure health hazards that may arise during the work.If the said recommendations are fully employed, then health hazards like over exposure to fumes can be minimized, if not eliminated. Thoriated Tungsten Electrodes Thoriated Tungsten Electrodes is one of the most used materials in welding. Thoriated tungsten has atomic number 90. Thorium is a radi oactive metal that emits alpha, and small amounts of beta and gamma particles. Thorium is one of the best welding materials due(p) to its long lasting, easy to use, low melting and low rate of consumption of electrodes. However, certain health hazards are associated to thorium. External exposure of a person to thorium is not a big deal.The real danger of thoriated tungsten is when dust particles during the grinding of the thorium is ingested or inhaled. If a person accidentally ingested or inhaled thorium from grinding it, there is a big potential of internal radiation to the person who ingested or inhaled the dust particles (American Welding Society AWS, 2003). The source of the thorium exposure is mainly derived from the grinding of the tungsten before use so that maximum arc stability of the electrode is achieved. In that process of grinding, thorium dust particles are released in to the open air that creates an unhealthy environment to welding personnel.Health officers in work areas should employ some recommendations in order to reduce the exposure of workers to thorium dust particles. In order to eliminate thorium dust particles, one should eliminate the use of thorium tungsten electrodes. Many thorium-free tungsten electrodes are available. Some of these are cerium, lanthanum, yttrium, and zirconium tungsten electrodes. If thoriated tungsten electrodes cannot be replaced, governance in work areas should utilize the use of proper handling of the said materials. That is following the Material Safety Data Sheet for thoriated tungsten electrodes.One should also take in to consideration the containment of the dust particles. This means that one should contain dusts created from grinding as soon as possible in order to prevent the health hazards associated to it. In addition to that, work area authorities should also assess the ventilations systems. In that way, one can control the flow of dust particles that is not contained so that workers will be able to prevent ingestion and ingestion of the said particles. Containment of the dust particles is only the first step. The next step after it is the disposal of the dust particles.Thoriated dust particles should be disposed properly and regularly. Disposal of thoriated tungsten electrode dust particles should be disposed with compliance to federal state (The Welding Institute, TWI, 2008). Radiation obtained from thoriated tungsten electrode can be prevented if one complies with the recommendations that are given from the previous paragraph. There should be someone who is able to check if a work place complies with the recommendations. Federal authorities are one of the many institutions that implement the recommendations of the American Welding Society (AWS).In addition to that, public health officers are also responsible in implementing the said recommendations. Furthermore, work places should also have their own health and safety officers that ensure a healthy working environment for i ts workers (American Welding Society AWS, 2003). Health risks in work places can be prevented in many ways. Recommendations made by some institutions are welcomed in order to have a healthy work place for welders. If strict implementation of health and safety recommendations made by AWS is enforced, health risks like internal radiation can be prevented.Knowledge is the appoint to being safe and healthy. Knowledge in proper handling of thoriated tungsten electrode and proper disposal of thoriated dust particles can eliminate hazards brought close to not only by thorium but also by all of the other materials that can cause health hazards. In the end, safety and health of workers will still be the concern of everyone. References American Welding Society. (October 2003). Chromium and Nickel in Welding Fume. Safety and Health Fact Sheet. Retrieved May 6, 2009 from http//files. aws. org/technical/facts/FACT-04.PDF American Welding Society. (October 2003). Thoriated Tungsten Electrodes. Safety and Health Fact Sheet. Retrieved May 6, 2009 from http//files. aws. org/technical/facts/FACT-27. PDF Nickel Development Institute (NDI). (March 2001). Stainless Steel and Welding Fume. Nickel Institute. Retrieved May 6, 2009 from http//www. nickelinstitute. org/index. cfm/ci_id/229. htm The Welding Institute (TWI). (2008). The Use of Thoriated Tungsten Electrodes. Retrieved May 6, 2009 from http//www. twi. co. uk/content/faq_thoriated. html

Methods Of Recovering Energy From Waste

Methods Of Recovering Energy From beetle offBiomass ( photocopy) vigour is increasingly attracting attention worldwide because it is a renewable source of capacity and potentially CO2 neutral. At present, most bumble materials are converted into electricity often by combustion. Waste combustion is widely applied for dominion heating and combined heat and power for electricity generation. This report describes burn out, waste reduction and preaching regulations in Europe as well as disparate types of waste devolved, an overview of waste to get-up-and-go technologies applied throughout the world today.Energy from waste has been evaluated based on their ability to reduce the emission of pollutant into the atmosphere. In golf club to mitigate climate change which is gaining increasing awareness, recent cultivations of different technologies that have been able to process waste to generate heat and power with high efficiencies push a side of meat be considered to be the most viable option to set back fossil fuels.2 INTRODUCTIONDue to the rising cost and the ecological disadvantages of fossil fuels, on that point as been concerns about the future of energy supply in the world. According to the World Energy Council, fossil fuel covers about 82% of the worlds energy. And this has caused severe reparation for the environment in terms of greenhouse emissions, sea level rising, air pollution, etc. Moreover, as the World continues to experience globalization, rapid industrialization and technological advancement, it leave certainly get to a point, where supply of these fossil fuels will not meet demand. thitherfore, it is imperative to find an alternative source of energy (Soetaert and Vandamme, 2006).Research and development of renewable sources of energy and energy from biomass is expected to be of immense benefit to the society as it reduces the concentration of carbon dioxide in the atmosphere and it is not exhaustible. Biomass is a major source of bi ologically derived bio fuels (bio-ethanol) and bio brag. This is considerably becoming a reality in energy/electricity generation. Biomass can be burnt directly to uncover heat or electricity, or it can be converted into solid, liquid or botcheous fuel through fermentation process into alcohol and anaerobic digestion into biogas. There are many environmental and social benefits associated with biomass energy. These include reduction in CO2 levels, energy carriers to rural communities, waste look, etc. (Calbe, Bajay, Rothman and Harry, 2000).Biomass raw materials for energy generation includes the first generation feedstocks i.e. energy crops (corn, sugarcane, wheat, etc) and the second generation feedstock mainly lignocellulosic materials (wood and agricultural residues). Hence, using biomass as a substitute for fossil fuels is sustainable and beneficial. However, at that place have been contentions on the use of humankind food (energy crop) for energy generation especially in developing countries where there is shortage of food. Hoffert et al. (2002), Dismiss the use of biomass for energy, opposites fulfil the opposite view (Dewulf and Langenhove 2006). To this effect, energy retrieval from waste can be an economical viable option.3 blowS3.1 DefinitionWaste arises as a provide of human technological development and social activities. The Uks Environmental Protection Act 1990 indicated waste includes any substance which constitutes a scrap material, an outgoing or other unwanted surplus arising from the application of any process or any substance or article which requires to be disposed of which as been broken, worn out, soil or otherwise spoiled, this is supplemented with anything which is discarded otherwise dealt with as if it were waste shall be presumed to be waste unless the contrary is proved. Murphy et al. (2002) defined waste as a material with no further beneficial use. The figure below shows the Schematic illustration of the EU Legal defi nition of waste3.2 EU WASTE cloth DIRECTIVEThe Directive requires all Member States to take the necessary measures to ensure that waste is recovered or disposed of without endangering human health or create harm to the environment and includes permitting, registration and inspection requirements. The Directive also requires Member States to take appropriate measures to encourage firstly, the prevention or reduction of waste takings and its harmfulness and secondly the recovery of waste by means of recycling, re-use or reclamation or any other process with a view to extracting unessential raw materials, or the use of waste as a source of energy (Department for Environment, Food and Rural Affairs, 2009).3.3 UK WASTE MANAGEMENT POLICYThe UK Waste polity is developed from the idea of sustainable development. This policy encourage diversion from landfills by imposing high tax levies on landfill site, reduce the amount of waste uncoverd by the commercial sector, and ultimately encou rage re-use and recycling of materials.3.4 WASTE HIERARCHYFigure 3.1 Waste hierarchy3.5 TYPES OF WASTEMunicipal Solid WasteHazardous/radioactive WasteSewage SludgeMedical/Clinical Waste farming(a) WasteIndustrial and Commercial WasteOther Waste e.g. construction and death industry waste, mines and quarry waste and power station ash, iron and steel slags (Williams, 1999).There are also two different kinds of component fraction in a waste period The Organic fraction i.e. Biodegradable and the In constitutional fraction.3.5.1Municipal Solid WasteThis is composed of/includes mainly household waste, with commercial and trade waste which is collected or disposed of by a municipality within an area. The composition of MSW streams varies, depending upon socio-economic factors, geographical locations, climate, population density and level of industrialization etc. for example in US and other industrialized countries where value is placed on time, consumers have adapted to the mentality of using disposable at all times, thereby impulsive packaging and wrapping technologies to a new level, in addition with the putrescible waste from food stuffs. The energy fraction contained in materials of this type of waste stream can be surrounded by 75 to 90%. Whereas in less developed countries where the waste stream is composed dominantly of putrescible fraction i.e. foodstuffs, vegetable and radical materials with minute packaging materials, the energy content will be much lower (Murphy, 2002).3.5.2 Hazardous WasteHazardous Waste is waste which contains substances that are considered to be dangerous to health and society. This includes substances which are reactive, infectious, harmful, toxic and corrosive etc. examples are chemicals such as, hydrogen cyanide, sulphuric acid, hydrofluoric acid etc. explosives such as dynamite, ammo etc. irrigate reactive chemicals such as potassium, phosphorous, sodium hydride etc. In USA, estimate arisings of hazard waste is 275 billion t onnes, UK 4.5 million tonnes, Germany 6 million tonnes, Spain 1.7 million tonnes (Williams, 1999).3.5.3 SEWAGE SLUDGESewage Sludge is usually generated at the waste water preaching facility. It is a by-product of the treatment of raw sewer from domestic households, which may also include commercial and industrial waste. The sewage is composed mainly of water, but after treatment, the moisture material is concentrated to phase sewage sludge (Williams, 1999). They are solid, semi-solid or bio solid in nature. Harper-Collins Dictionary of Environmental Science defines Sewage Sludge as a semi-solid mixture of bacteria, virus-laden organic matter, toxic metals, synthetic organic chemicals, and settled solids removed from domestic and industrial waste at sewage treatment plants. (Renewable Energy Institute) The sewage sludge treatment undergoes both aerobic and anaerobic digestion and the final treated sewage sludge is either land filled, mobilise on land as fertilizers or incinerated. upstart developments have sh admit that biogas can be produced during anaerobic digestion.3.5.4 CLINICAL WASTEClinical Waste is mainly produced/waste arising from health centres, hospitals and nursing homes etc. Examples include drugs, syringes, needles, blood, human or animal tissue etc. Approximately 0.3 millions tonnes of clinical waste arises in the UK annually. Majority of clinical waste are incinerated (Williams, 1999).3.5.5 AGRICULTURAL WASTEAgricultural waste is waste streams generally produced from agricultural activities. They are produced within agricultural premises and they include organic materials such as slurry, manure from livestock, silage effluent and crop residues. It is estimated that approximately 700 million tonnes of agricultural waste is produced in OECD countries. UK also produces large tonnage, 80 million tonnes estimated from housed livestock alone (Williams 1999).3.5.6 INDUSTRIAL AND COMMERCIAL WASTEThese are types of waste stream that arises from both industrial and commercial sectors such as hotels and catering, food, drink and tobacco manufacturing industries, metal manufacturing industries, timber and wooden furniture industries, mechanic and electrical industries, transport and communication industries etc. The typical composition of this waste streams differs and very wide. A survey carried out by Environmental Agency of nearly 4,500 commercial and industrial businesses in England in 2002/2003 showed that commercial waste amounted to 30 million tonnes and industrial waste 38 million tonnes (mt). In that survey, the main sectors producing CI wastes were retail (12.7mt), food, drink and tobacco (7.2mt), professional services and other (7.1mt), utilities (6.2mt), the chemicals industries (including fibre, rubber and plastics) (5.3mt), basic metal manufacture (4.8mt) and hotels/catering (3.4mt) (Defra, commercial and industrial waste in England, 2009).4 ENERGY RECOVERIES FROM WASTE TECHNOLOGIESEnergy is recovered from waste e ither through thermal combustion or biological/chemical reactions. The energy recovery process produces electricity directly through combustion, or produces synthetic and combustible fuel i.e. methane.4.1 INCINERATIONIncineration with energy recovery is the controlled combustion of waste and it is the most wide spread waste to energy implementation. It involves the combustion of waste streams at high temperatures and the heat produced can be used to drive a turbine in order to produce electricity and district heating. Waste materials or fuel are fed into incinerators in two ways, the mass discharged/burning systems and refuse derived fuel (RDF) fired systems. The mass burning involves minimal processing the entire mixed municipal solid waste is fed into a furnace without any removal/separation of reusable and non combustible materials. For RDF fired technologies, MSW undergoes pre-treatment, separation of non-combustible and recyclable material which is known as RDF. RDF fired sys tems has a higher energy content compared to unprocessed MSW because of its homogeneity (Tchobanoglous, Thiesen and Vigil, 1993).There are various types of incinerator plant design moving grate, fixed grate, rotary-kiln, and fluidized bed incinerator.4.1.1 Moving GrateThis can also be called Municipal Solid Waste incinerators. The moving grate enables the movement of waste by a waste crane at one end of the grate through the combustion chamber to the ash pit at the lower end. The combustion air is supplied through the grate lying below. Cooling of the grate itself is essential for the mechanical strength of the grate. wiz single moving grate boiler can handle 35 metric tonnes of waste per hour, and 8,000 hours per year.4.1.2 Fixed GrateThis is a simpler type of incinerator. It is made of a brick lined compartment with a fixed metal grate above the lower ash pit, with one opening for loading and another opening in the side for removing incombustible solids known as clinkers.4.1.3 R otary kilnIt is mostly used by municipalities and large industrial plants. Rotary kiln incinerators have 2 chambers, primary and secondary chamber. In the primary chamber, movement and conversion of solid fraction of the waste to gases and partial combustion occurs while the secondary chamber completes the gas phase combustion reactions.4.1.4 Fluidized backsideFluidized Bed Combustion (FBC) is a combustion technology used in power plants. FBC developed from efforts to find a combustion process that is able to control pollutant emissions. Advanced fluidized bed combustion offers a viable power generation technique. In fluidized bed combustion, a strong airflow is forced through a sand bed, which keeps the waste suspended on pumped air currents and takes on fluid like character. Due to the turbulent mixing, the waste and sand are full circulated through the furnace.4.2 BALDOVIE WASTE TO ENERGY PLANTThe Baldovie waste to energy plant is a state of the art facility commissioned in Dund ee in 1999, to replace a waste disposal incinerator due to its inability to meet EU requirements on emissions. The plant is run by a joint venture between Dundee city council and private sector partners. The joint venture is collectively called Dundee energy recycling limited (DERL). The plant processes 120,000 tonnes of waste annually and generates electricity to meet its own demand (about 2.2MW) and also supply to the public (about 8.8MW). Separation techniques carried out before combustion removes and recovers ferrous metals which can be resold (Gazetteer for Scotland, 2010).4.3 LANDFILL GAS CAPTURELandfill is a waste disposal site where waste is deposited onto or into the land. When waste is deposited, it undergoes various degradation process which produces gas mainly methane. Modern landfills have gas recovery systems, where the landfill gas is extracted and can be used for production of steam, heat and electricity (Dewulf and Langenhove 2006, p.248)4.4 ANAEROBIC DIGESTIONAnaer obic treatment technologies are used throughout the world for effective treatment of organic waste. This technology is particularly attractive because the energy required for operating the process is minimal compared to energy required for aerobic process. Anaerobic digestion is a obscure biogenic process which involves the microbial degradation or conversion of organic waste in a closed reactor vessel (absence of air) to produce gas chiefly methane (55-65%), CO2 (35-45%), and trace amounts of N2, H2 and H2S, depending on factors such as the composition of waste, organic loadings applied to the digester, time and temperature. The methane-rich biogas which can be combusted to generate heat and electricityIn general anaerobic digestion is considered to occur in three stagesA Liquefaction or polymer sectionalisationB Acid formation andC Methane formationSubstrates for anaerobic digestion includes waste water from food processing, breweries, distilleries etc. sewage sludge, animal was te, farm residues.4.5 GASIFICATION AND PYROLYSISGasification is defined as a partial oxidation/combustion of biomass and various combustible waste/ carbonous fuels to produce gas. This gas can be used in internal combustion engines and gas turbines to generate electric power.Pyrolysis is a thermal process which involves the breakdown of organic materials in waste under pressure in the absence of oxygen. The pyrolysis process produces a liquid residue and gas which can be combusted to generate electricity.The principal difference between the two systems is that, pyrolysis system use an external source of heat to drive the endothermic pyrolysis reaction in an oxygen detached environment, whereas gasification systems are self-sustainable and use air or oxygen for partial combustion of solid state (Tchobanoglous, Thiesen and vigil 1993).5 CONCLUSIONSEnergy from waste has been evaluated based on their ability to reduce the emission of pollutant into the atmosphere, minimise waste, and g enerate heat and power.With the recent development of different technologies that have been able to process waste to generate energy with high efficiencies, waste to energy technologies can be considered to be viable substitute/option for fossil fuels for electricity generation and also in minimizing of waste accumulation.

Empirical evaluation of accounting income

Empirical evaluation of accounting incomeWith the rise of multinational companies and the growth of transnational investments, there has been an increasing demand for an verifiable evaluation of accounting income metrical composition. The Ball and browned use up in 1968 broadens this argona of accounting research. With the rapid development of the literature, there argon more than 1000 make papers in academic accounting and finance journals in the last thirty years (Kothari, 2001). However, several accounting experts assert that there are whatever weaknesses in the research of Ball and Brown. Meanwhile, critics argue that their empirical evaluation contributed to the accounting research since previous(a) 1970s. The purpose of this essay is to introduce the strengths of Ball and Browns paper and point its cast on the development of accounting. This essay will argue that the limitation of the paper is non serious, but its advantages are very brandificant. First, arguments fo r and against the empirical research are discussed. Then, an evaluation is explored .Lastly, a conclusion is presented.2. The weaknesses of the paperThe major motivation of the Ball and Brown study is to use empirical evidence to prove whether the accounting income metrical composition convey instruction of firms financial surgical procedure. They pioneered capital food market places research in accounting. However, their study still has some weaknesses.2.1 UnreliabilityThe reliability of their results depends on the sources of information, which may be a potential limitation of the study. Although we are not disputing the reliability of the said sources, they should be investigated. Research should be conducted to document various types of institutions. According to Zhang (2007), the selection of the sample did not include companies meet the following four conditions. The first one is the failed participation. The second one is a company whose financial year does not end on the 31st of December. The third one is the company that is not recorded in the CRSP database of stock price research centers. It also includes the young firm that is not draw by the Wall Street Journal. Given those situations, the generality and reliability of their results may be reduced.2.2 LimitationsThe research firmly supposes that some information of stock prices can be reflected by the earnings. However, the Ball and Brown study did not use a statistical test to ascertain whether there is any difference between earning information and the information reflect in the stock prices.Rayburn (1986) asserts that stock returns have been statistically compared with cash lights, earnings, and accruals during the 1980s. Aside from providing a formal test, sketchy information of cash flow was used in previous research. The succeeding studies used more comprehensiveness expectation models to separate the unanticipated components of earnings, accruals, and cash flows, given that returns in an efficient market only reflect the unpredicted components (Livnat et al., 1990).ListenRead phonetically3. The strengths of the paperAlthough the weakness of this paper is obvious, the design of variables and the results of the test have made outstanding contributions to research of accounting income.3.1 talented design of variablesAfter identifying the research themes, Ball and Brown selected the most representative accounting income total to measure the information content. Considering that assignholders are more concerned nearly EPS and net income, Ball and Brown used them as variables. To determine the information content of the accounting income, they used market efficiency hypothesis and the capital asset pricing model as references.According to the efficient market hypothesis, the authors maintained that observable stock price is fluctuant and linked with information. This can mean that accounting income numbers are useful. The key to determining the relationship be tween accounting income and stock price is to distinguish the security prices of a particular company as easy as all the other companies. Therefore, the authors built two models of market judge return to examine how the market reacts to accounting income numbers.Ball and Brown separated factors that repair earning into two different kinds specific factors and constitution factors. System factors affect all companies, thus, the surfeit of one company and other companies can be linked with apiece other. If the link is suitable, then stability can be shown using a fixed function, enabling us to achieve the income qualified expectation of one company based on other companies data. Thus, changes in the unexpected surplus of earning can be estimated by calculating by the changes in both actual income and conditional expectation. The authors defined the difference as the gain of current information. At the same time, they assumed that the changes in policy and corporate have been en acted before the first estimation. Thus, the influence of macroeconomic and policy changes can be estimated jointly.The authors initially used the Ordinary Least Squares (OLS) to estimate the linear regression coefficient and intercept of samples annual income changes and average income changes. Secondly, the changes in the market income average were used as independent variables and included in the regression model to calculate the expected value of income changes. Finally, the changes in the value of unexpected earnings (prediction residual) referred to the actual value of the earnings change minus the change in earnings expectations. Therefore, market effect was removed from the estimation of expected surplus, which performer the authors did not take system factors into account.Similarly, the factors affecting the impact of no stock or stock returns can still be separated into two factors system factors and specific factors. First, the authors used capital asset pricing model to separate the system factors and from non-system factors, then calculated the deviation of actual rate return and expected stock return. Secondly, Ball and Brown calculated the companys stock return residuals (abnormal returns). Given that markets are efficient, stock prices will adjust quickly and effectively about the in the buff information, so residuals can show the impact on stock prices of new information. To test the validity of statistics, Ball and Brown used an alternative model- naive model. In this model, an alternative variable is the expected surplus for last years actual surplus. The naive model does not eliminate the market effects, but verifies the earnings per share targets.3.2 Remarkable resultsThis paper distinguished expected changes and unexpected changes in accounting incomes to estimate the abnormal return and changes in unexpected accounting incomes. In addition, it theorized that when the surplus prediction error is negative, it is both advantageous and dis advantageous. This paper presented the hypothesis that if the accounting income numbers could be linked with stock prices, then the annunciation of accounting income numbers could result in changes in the stock returns. In the empirical test, the authors defined the calendar month of annual report as 0, API representing the abnormal performance index of month M. In the process of calculating the API, the changes in unexpected earning are first separated into two groups (positive and negative), and then all samples are calculated together. Ball and Brown thought that if accounting income is related to stock returns, it can be assumed that if the changes in unexpected surplus are positive, then API is larger than 1 if they are negative, then the API is less than 1. In the combined sample, API is close to 1.Ball and Brown thought that annual income report can provide new information however, it cannot be transmitted in time, because most of its content comes from various sources (inter im report and non-accounting information, annual accounting report is only one of them) .The authors also found that after the announcement of the annual report, API has a tendency to drift on, that is, revenue projections residual error signal and the relationship between stock returns in the annual report may be continued for two months. After analysis, which may be caused by the transaction costs, and excluding the impact of transaction costs, the market reaction to the numbers tends to be unbiased.4. military rankAt first glance, one weakness of this empirical research is the limitation of the sample which may decrease the generality and reliability of the results. However, the selection of the sample was quasi(prenominal) to the tests used in related literature, which could lead to consistent results if used the same way on other samples.The weaknesses of the paper also include the limitation of the statistical tests. Nonetheless, it had a significant impact on later research . In 1968, the Ball and Brown study shows that accounting earning announcements contain information content. In the meantime, they link the sign of monthly abnormal stock return with the sign of the previous years earnings change. Starting with Ball and Brown, many studies began to compare alternative accounting performance measures, such as historical cost earnings, current cost earnings, residual earnings, and operating cash flows with stock returns. Under the similar circumstances, the Ball and Brown study also facilitated Watts and Zimmermans positive accounting theory in the late 1970s (Watts and Zimmerman, 1979). As Watts and Zimmerman (1990) point out, most accounting research since Ball and Brown has been positive, and the component of accounting theory is no longer normative.According to Kothari (2001), Ball and Brown heralded the positive-economics-based empirical capital markets research in the late 1960s. The theoretical and methodological innovation of the early accoun ting research was founded by the concurrent developments in economics and finance. Without this historical exploring of Ball and Brown in early capital market research, even seasoned researchers may have to detour or lose continuity.In addition, this paper analyzes the insufficiency of theoretical studies using empirical testing to vex out whether the accounting income numbers are useful. It initially provides reliable evidence that stock markets can influence annual reports. Then researchers began to do a corporation in reflect of stock market. Furthermore, the method used is also applicable to a large number of accounting and financial issues, including dividend announcements, earnings announcements, mergers and acquisitions, and investment spending.5. inferenceThis essay has discussed the weaknesses and strengths of the empirical evaluation of accounting income numbers by Ball and Brown. Although this research has some limitations, the merits far outweigh the disadvantages. It preceded the positive-economics-based empirical capital markets research of the late 1960s. The theoretical and methodological innovation of the early accounting research was founded by the concurrent developments in economics and finance. Therefore, it is suggested that this research plays a great role in the development of accounting .In this essay, only a few strengths are mentioned the ways of putting these benefits into practice need further exploration.

The structure of a commercial aircraft

The construction of a commercial aircraftIntroductionThis is assignment is based on structure of an aircraft. The structure of an aircraft has been explained briefly in this assignment. I am passing game to start my assignment with typical aircraft diagram. This assignment is particular based on commercial aircraft, emphasising various major structural components. The major structural components refer to the original structure of an aircraft. If the primary structure fails the aircraft wont be capable of flying anymore. It can lead to complete structural damage. I am going to do an intensive research on load transfer structure using Aircraft structure from engineering book, and I am going to explain ab knocked out(p) the utter some load case which will cover N-V diagram as wellStructure ClassificationFor the purpose of assessing damage and the type of repair to be carried out on the aircraft the structure is divided into three main categoriesPrimary StructureSecondary StructureTe rtiary StructurePrimary StructurePrimary structure includes all the portions of the aircraft, the failure of which during flight or on the ground would cause catastrophic structural collapse and loss of control.Examples of Primary Structure include travelFuselageTailLanding GearWingsWing is a surface providing the lift to the aircraft. They be attached to fuselage on each side .They are ordinarily in aerofoil shape. They can be attached at the top, middle, or lower portion of the fuselage depending on the required performance for the particular airplane. The number of fly can withal vary.The gos consist of two essential parts. The internal wing structure which consist of spars, ribs, stringers and the external wing, which is the bark.CUsersRIZWAN ULLAHPictureswing-components.gifFig 2 Components of the wing (2)In a fixed-wing aircraft, the spar is the main structural member of the wing, situated at right angle to the fuselage racetrack spanwise. They run from the base of the w ing toward the tilt and are usually attached to the fuselage by the wing fittings. It carries flight loads and the weight of the wing. Sometimes more than one spar may be primed(p) on a wing or there might be none at all (3)In the framework of a wing, ribs are the crosspieces running from the leading edge to the trailing edge of the wing. The ribs give the wings its contour and shape and transmit the load from the skin to the spars. Ribs are also used in ailerons, elevators, fins and stabilizer (4)Stiffener which assists sheet materials to carry loads along their length. With integral construction they are machined or etched out of the skin panelFuselageThe body of the airplane, which carries the conspiracy and payload, such as passengers or cargo, is called the fuselage. It looks like a tube which holds most of the aircraft together. The other structural units are directly or indirectly attached to it. It also provides stableness and also control pitch and yaw movement of the ai rcraftCUsersRIZWAN ULLAHPictureshttpimages.google.co.ukimgresimgurl=httpwww.grc.nasa.govWWWK-12airplaneImagesfuselage.gifimgrefurl=httpwww.grc.nasa.govWWWK-12airplanefuselage.htmlusg=__JKzqTJ1GPBfQcNIPubnvd2PTbqk=h=533w=710sz=22hl=enstart=1sig2=YzE.jpg (5)Fig 3 FuselageTypes of StructureThere are two contrastive types of structureMonocoque typeSemi Monocoque typeCUsersRIZWAN ULLAHPicturesUntitled.jpg (6)Fig 4 Warren truss of welded tubular steelMonocoque ConstructionThis is yet classified into the uncoiled Monocoque construction and the more common semi Monocoque construction.The true Monocoque construction uses formers, frames assemblies, and bulk heads to give shape to the fuselage, but the skin carries the primary var.es. Since the bracing members are present, the skin must be strong enough to keep the fuselage rigid. Thus, the biggest problem involved in Monocoque construction is maintaining enough strength while keeping the weight at heart allowable limits.CUsersRIZWAN ULL AHPictureshttpairplanegroundschools.comAircraft-StructureFigure1-3.jpg.jpg (7)Fig5 Monocoque ConstructionSemi Monocoque ConstructionThe semi monocoque fuselage is constructed primarily of the alloys of aluminium and magnesium, although steel and titanium are found in areas of high temperatures.CUsersRIZWAN ULLAHPicturessemimonocoquefuselagedesign1.jpg (8)Fig6 Semi Monocoque ConstructionThe principal structural parts of the fuselage are longerons, formers, stringers and bulkheadsLongerons are main structural member of a fuselage or nacelle. Longerons are a slue strip of metal to which the skin of the aircraft is fastened. Longerons are attached to formers in the case of fuselage (9)The vertical structural members are referred to as bulk heads, frames and formers. The heaviest of these vertical members are located at intervals to carry concentrated loads and at points where fittings are used to attach other units, such as the wings, power plants, and stabilizersTailThe stabilizing su rfaces at the rear of the airplane are the swimming and vertical tails. These major components are often divided into smaller elements. The forward, usually fixed, part of horizontal tail is the horizontal stabilizer. Attached to it is a movable control surface called elevator. Changing the elevator deflection changes the lift on the horizontal tail and thereby controls the angle of access and lift of the wing. Similarly, the vertical tail is divided into the fixed vertical stabilizer or fin and the rudder.The main role of horizontal stabilizer is to provide longitudinal stability about lateral axis. It refers to motion in pitch thereby it controls the angle of attack.The main role of the vertical stabilizer is to provide directional stability about the normal axis. It controls the yawing motion of an aircraft.(10)Fig7 EmpennageLoad Transfer StructureThe basic function of an aircrafts structure are to transmit and resist the loads utilize on aircraft so the structure can provide aerodynamic shape and protect the aircraft from environmental conditions encountered in flight.The two classes of loads may be further divided into surface forces which dress upon the surface of the structure and body forces which act over the volume of the structure and are produced by gravitational and inertial effects. basically all air loads are the expiry of the pressure distribution over the surfaces of the skin produced by steady flight, manoeuvre or gust conditions. Generally, these resultant cause direct loads, bending, shear and torsion in all parts of the structure.First, we shall consider wing sections, while performing the same function can take issue widely in their structural complexity. The shape of the cross section is governed by aerodynamic considerations and clearly must be maintained for all combinations of load. They also act with the skin in resisting the distributed aerodynamics pressure loads they distribute concentrated loads into the structure and redi stribute sift around discontinuities, such as undercarriage wells, control panels and fuel tanks, in the wing surface. Ribs increase the column buckling stress of the longitudinal stiffeners by providing end restraint and establishing their column length in a correspondent manner they increase the plate buckling stress of the skin panels. In the outer portions of the wing, where the cross section may be relatively small if the wing is fall and the loads are light, ribs act primarily as formers for the aerofoil shape.Fuselages, while of different shapes to the aerodynamics surfaces, comprise members which perform similar functions to their counterparts in the wings and the tailplane. aerodynamics forces on the fuselage skin are relatively low on the other hand, the fuselage supports large concentrated loads such as wing reactions, tailplane reactions, undercarriage reactions and it carries payloads of change size and weight, which may cause large inertia forces. (11)Maximum Stre ss Load caseMany forces and structural stresses act on an aircraft. When it is static, the force of graveness produces weight, which is supported by the landing gear. During flight manoeuvre causes acceleration or deceleration which increases forces and stresses on wings and fuselage.V-n Diagram (15)CUsersRIZWAN ULLAHPicturesimage2.gifFig 8 lead DiagramThis diagram illustrates the variation in load component with airspeed for maneuvers. At low speeds the maximum load factor is constrained by aircraft maximum CL. At higher speeds the maneuver load factor may be restricted.The maximum manoeuvre load factor is usually +2.5 . If the airplane weighs less than 50,000 lbs., however, the load factor must be given by n= 2.1 + 24,000 / (W+10,000)n need not be greater than 3.8. This is the required manoeuvre load factor at all speeds up to Vc, unless the maximum achievable load factor is limited by stall.The structural stresses to which the aircraft is subjected to its maximumTensionCompress ionTorsionShear change shapeTensionIt is defined as pull, in level flight, aircraft engine and propeller pulls the aircraft forward while fuselage and tail resist that movement because of the airflow around them. Airframe is stretched as a result.Elevator control cable is in additional strain when the pilot moves the control columnCompressionCompression is the resistance to crushing. Aircraft wings are subjected to compression stresses, on the ground aircraft landing gear struts are under compression stressCUsersRIZWAN ULLAHPicturesaaaa.jpg (12)Fig 9 Compression and tension stressTorsionIt results from a twisting force. It is produced in an engine crankshaft while the engine is running. The airframe is also subjected to stresses during turns.CUsersRIZWAN ULLAHPicturesUntitled.jpg (13)Fig 10 Torsional stressShearShear stress is the outcome of sliding one part over the other in opposite directions. The rivets and bolts experience shear stresses.BendingBending is a combination of tens ion and compression. The wing spars of an aircraft in flight are subject to bending stressesCUsersRIZWAN ULLAHPictureshttpwww.aerospaceweb.orgquestionperformanceq0146.shtml.gif (14)Fig 11 Banking angleWhen the aircraft is taking a sharp turn most of the forces acting on the aircraft are its at maximum, because there are forces that tend to keep the aircraft in its original path.

A Critique of The Giver :: Giver Essays

A Critique of The Giver        The purpose of this curb was to show us a possible version of a Utopia. It  was a fantasy oriented book, that was suppose to make you think about the possibilities for the future.  The setting is a supposedly staring(a) society where everyone is taken care of and no one is different.  The author Lois Lowry does a fine job portraying this supposedly reportl society.         This book began with a exposition of sameness and release the two general principles the society functions on.  It then continues while Jonas (the main character) waits to receive his naming in the community.  Waiting to find out what his assignment is, and what it entails doing are  rises in action. The climax is when the plan to escape the society is being conceived and the actual escape itself.  The falling action is when he is escaping from the search planes and trying to conceal himself and Gabriel alive.  The ending is when he feels triumph at the top of the hill and then sleds down it to his new family, his first memory that belongs to him.        There were many characters in this book the main one being Jonas.  Jonas is a child in this supposed Utopia who ends up with the most important assignment of all the manslayer of Memory.  The pass catcher h olds all the memories of the whole community so the community does not have to be bothered with feelings and the emotional baggage that comes with them.  Jonass trainer the Giver is a old man who passes the memories on to Jonas and eventually thinks of the plan to escape.  The Giver also adopts Jonas and Rosemary as his own kids in a way.  He had a previous Receiver named  Rosemary who applied for and received release. Release is the term for death in this community.  So when Rosemary was  released her memories went back to the community.  Jonas and the Giver were talking about this when the Giver got the idea of how to get Jonas away from the community and get the community back its emotions and feelings.  Gabriel was a another influential character he was a baby staying with Jonass family  till he was

Night in William Shakespeares A Midsummer Nights Dream Essay examples

Night in William Shakespeares A Midsummer Nights DreamOne of the recurring themes throughout Shakespeares A Midsummer Nights Dream is the time of day during which the plays major action takes place night. This being the case, there are certain words that are immediately linked to this theme that appear numerous times throughout the script. Four such words are moonlight, moonlight, moonshine, and lunatic. Each comes from a feminine root that serves to appoint the women in the play as prizes to be won and controlled.It becomes clear when looking up the term moon in the Oxford side Dictionary that the word is associated with the feminine. In poetry, for instance, the moon is often personified, always as young-bearing(prenominal) (1050). It is important to note that the play upsets traditional cultural customs in this regard, for May was the time of female fertility over which the moon presided, but the play begins with an image of lunar age and sterility, a dowager, a cold fruitles s moon (Paster and Howard, Popular Festivals 93). It is thinkable that Shakespeare applied such images intentionally to make it clear to his audience that the women in this play are not as free as the May daytime festivities might make them out to be. The female fertility that is expressed freely in Shakespeares blend of May Day and Midsummers eventide is outside of the controlled realm of marriage. Instead of the unrestrained women that both holidays celebrate, however, Shakespeare bookends the play with a woman tamed by a man.In the first scene, the moon is mouth of by Theseus and Hippolyta as a measurement of time when Theseus announces, four happy days bring in / Another moon but, O, methinks, how slow / This old moon wanes She linger... ...more.Works CitedBrown, Lesley, ed. The New Shorter Oxford English Dictionary. 5th ed. Oxford Clarendon, 1993.moon, moonlight, moonshine, and lunatic. Shakespeare Concordance. 23 Feb. 2006 .Paster, Gail Kern, and Skiles Howard. Female Att achments and Family Ties. A Midsummer Nights Dream Texts and Contexts. Ed. Gail Kern Paster, and Skiles Howard. Boston and New York Bedford/St. Martins, 1999. 192-264.---. Popular Festivals and royal court Celebrations. A Midsummer Nights Dream Texts and Contexts. Ed. Gail Kern Paster, and Skiles Howard. Boston and New York Bedford/St. Martins, 1999. 89-99.Shakespeare, William. A Midsummer Nights Dream. A Midsummer Nights Dream Texts and Contexts. Ed. Gail Kern Paster, and Skiles Howard. Boston and New York Bedford/St. Martins, 1999. 1-86.The Oxford English Dictionary. 2nd ed. 1989.

Intimacy in A Streetcar Named Desire, by Tennessee Williams Essay

IntimacyTennessee Williams used his life experiences to write many prospering interprets. One of his most successful plays is A Streetcar Named Desire. In this play Williams relates the characters closely to his father, flummox, and sister. Williams father was a gambler, a drunk, and very aggressive. Williamss bugger off was a Southern Bell and looked down upon people that were not like her, and his sister was suffering from psychological disorders. Stanley is like Williams father, Blanche is like Williams mother and sister, and Allan, Blanches dead husband, is like Tennessee Williams. Suchitra Choudhury says that Tennessee Williams plays are acknowledged to be substantially constituted of violence and victimization. . . . Williamss plays very often end in what seems to be victimization. The play A Streetcar Named Desire is a classic example of violence and victimization. Stanley is very violent and Blanche is the victim, her past haunting her in the present. Throughout the play we see how Blanche evolves into what seems to be a psychotic breakdown at the end. We see how the need for intimacy ultimately causes her to become psychotic. Blanche struggles with the death of her husband Allan, and as a result she is constantly trying to create a reality of what she believes life should be like. How does the past affect Blanche in the present?Blanche strives to deny the past and come on a new life for herself, one that she perceives to be what she deserves. Blanches promiscuity in Laurel is the result of her constant search for intimacy, not just sex. Blanche struggles with guiltiness that it is her fault her husband Allan commits suicide. Even though Stella and Stanley and even Eunice and Steve have what she thinks are horrible relatio... ...n, Leonard. The Tragic Downfall of Blanche Dubois, ModernDrama, Vol. 10, No. 2, December, 1967, pp. 24957. http//galenet.galegroup.com.ezproxy.maconstate.edu/servlet/LitRC?locID=maco12153&ADVST2=NA&srchtp=adv&c=6&stab=51 2&ASB2=AND&DT=Criticism_select&ADVSF2=tennessee+williams&docNum=H1100001574&ADVSF1=a+streetcar+named+desire&ADVST1=TW&bConts=514&vrsn=3&ASB1=AND&ste=74&tbst=asrch&tab=2&ADVST3=NAChoudhury, Suchitra. A Streetcar Named Desire. Great Neck Publishinghttp//proxygsu-mac1.galileo.usg.edu/login?universal resource locator=http//search.ebscohost.com/login.aspx?direct=true&db=lfh&AN=25997558&site=ehost-liveLiterary Contexts in Plays Tennessee Williams A Streetcar Named Desire.Williams, Tennessee. A streetcar Named Desire. The Norton Introduction to Literature. 9th Edition. Alison Booth, J. Paul Hunter, Kelly J. Mays Ed. NewYork. W. W. Norton, 2005 (1539-1602)