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英文文献翻译

外文文献原稿和译文原稿Sodium Polyacrylate:Also known as super-absorbent or “SAP”(super absorbent polymer), Kimberly Clark used to call it SAM (super absorbent material). It is typically used in fine granular form (like table salt). It helps improve capacity for better retention in a disposable diaper, allowing the product to be thinner with improved performance and less usage of pine fluff pulp. The molecular structure of the polyacrylate has sodium carboxylate groups hanging off the main chain. When it comes in contact with water, the sodium detaches itself, leaving only carboxylions. Being negatively charged, these ions repel one another so that the polymer also has cross-links, which effectively leads to a three-dimensional structure. It has hige molecular weight of more than a million; thus, instead of getting dissolved, it solidifies into a gel. The Hydrogen in the water (H-O-H) is trapped by the acrylate due to the atomic bonds associated with the polarity forces between the atoms. Electrolytes in the liquid, such as salt minerals (urine contains 0.9% of minerals), reduce polarity, thereby affecting superabsorbent properties, especially with regard to the superabsorbent capacity for liquid retention. This is the main reason why diapers containing SAP should never be tested with plain water. Linear molecular configurations have less total capacity than non-linear molecules but, on the other hand, retention of liquid in a linear molecule is higher than in a non-linear molecule, due to improved polarity. For a list of SAP suppliers, please use this link: SAP, the superabsorbent can be designed to absorb higher amounts of liquids (with less retention) or very high retentions (but lower capacity). In addition, a surface cross linker can be added to the superabsorbent particle to help it move liquids while it is saturated. This helps avoid formation of "gel blocks", the phenomenon that describes the impossibility of moving liquids once a SAP particle gets saturated.History of Super Absorbent Polymer ChemistryUn til the 1980’s, water absorbing materials were cellulosic or fiber-based products. Choices were tissue paper, cotton, sponge, and fluff pulp. The water retention capacity of these types of materials is only 20 times their weight – at most.In the early 1960s, the United States Department of Agriculture (USDA) was conducting work on materials to improve water conservation in soils. They developed a resin based on the grafting of acrylonitrile polymer onto the backbone of starch molecules (i.e. starch-grafting). The hydrolyzed product of the hydrolysis of this starch-acrylonitrile co-polymer gave water absorption greater than 400 times its weight. Also, the gel did not release liquid water the way that fiber-based absorbents do.The polymer came to be known as “Super Slurper”.The USDA gave the technical know how several USA companies for further development of the basic technology. A wide range of grating combinations were attempted including work with acrylic acid, acrylamide and polyvinyl alcohol (PVA).Since Japanese companies were excluded by the USDA, they started independent research using starch, carboxy methyl cellulose (CMC), acrylic acid, polyvinyl alcohol (PVA) and isobutylene maleic anhydride (IMA).Early global participants in the development of super absorbent chemistry included Dow Chemical, Hercules, General Mills Chemical, DuPont, National Starch & Chemical, Enka (Akzo), Sanyo Chemical, Sumitomo Chemical, Kao, Nihon Starch and Japan Exlan.In the early 1970s, super absorbent polymer was used commercially for the first time –not for soil amendment applications as originally intended –but for disposable hygienic products. The first product markets were feminine sanitary napkins and adult incontinence products.In 1978, Park Davis (d.b.a. Professional Medical Products) used super absorbent polymers in sanitary napkins.Super absorbent polymer was first used in Europe in a baby diaper in 1982 when Schickendanz and Beghin-Say added the material to the absorbent core. Shortly thereafter, UniCharm introduced super absorbent baby diapers in Japan while Proctor & Gamble and Kimberly-Clark in the USA began to use the material.The development of super absorbent technology and performance has been largely led by demands in the disposable hygiene segment. Strides in absorption performance have allowed the development of the ultra-thin baby diaper which uses a fraction of the materials – particularly fluff pulp – which earlier disposable diapers consumed.Over the years, technology has progressed so that there is little if any starch-grafted super absorbent polymer used in disposable hygienic products. These super absorbents typically are cross-linked acrylic homo-polymers (usually Sodium neutralized).Super absorbents used in soil amendments applications tend to be cross-linked acrylic-acrylamide co-polymers (usually Potassium neutralized).Besides granular super absorbent polymers, ARCO Chemical developed a super absorbent fiber technology in the early 1990s. This technology was eventually sold to Camelot Absorbents. There are super absorbent fibers commercially available today. While significantly more expensive than the granular polymers, the super absorbent fibers offer technical advantages in certain niche markets including cable wrap, medical devices and food packaging.Sodium polyacrylate, also known as waterlock, is a polymer with the chemical formula [-CH2-CH(COONa)-]n widely used in consumer products. It has the ability to absorb as much as 200 to 300 times its mass in water. Acrylate polymers generally are considered to possess an anionic charge. While sodium neutralized polyacrylates are the most common form used in industry, there are also other salts available including potassium, lithium and ammonium.ApplicationsAcrylates and acrylic chemistry have a wide variety of industrial uses that include: ∙Sequestering agents in detergents. (By binding hard water elements such as calcium and magnesium, the surfactants in detergents work more efficiently.) ∙Thickening agents∙Coatings∙Fake snowSuper absorbent polymers. These cross-linked acrylic polymers are referred to as "Super Absorbents" and "Water Crystals", and are used in baby diapers. Copolymerversions are used in agriculture and other specialty absorbent applications. The origins of super absorbent polymer chemistry trace back to the early 1960s when the U.S. Department of Agriculture developed the first super absorbent polymer materials. This chemical is featured in the Maximum Absorbency Garment used by NASA.译文聚丙烯酸钠聚丙烯酸钠，又可以称为超级吸收剂或者又叫高吸水性树脂，凯博利克拉克教授曾经称它为SAM即：超级吸收性物质。

国际服务贸易外文文献翻译

国际服务贸易外文翻译文献(含：英文原文及中文译文)文献出处：《World Development》，2015，12（1）：35-44.英文原文The research of international service trade and economic growth theoryChakraborty Kavin1 IntroductionThe study of the relation between international trade and economic growth is one of the most active issues. Since 1980s, the world has been in transition from national economy orientating towards natural resources and manufacturing industry to global and regional economy orientating towards information resources and service industry. After the signature of GA TS in1994, the institutional arrangements on liberalizing service trade result in a world-wide involvement division and exchanges of service trade, and it is undoubtedly that the positive interaction between service trade and investment leads to economic growth. But the theoretical research on service trade lags behind practice.Is it a statistic phenomenon or a universal rule of economic growth? To approach the above two issues from theoretical and empirical perspective is of great value to policy-making.For the proposition of that "International service trade will drive economic growth". Theoretical analysis shows that although service tradeis not a direct interpretative variable to economic growth, it can effect economic growth indirectly through other growing factors and technology upgrade, but the ways and mechanisms are different in different stages. In a certain stage of economic development, service trade (including investment) will have static and dynamic effect on factors supply and technology upgrade in one county, which will lead to the domestic alteration of resources condition structure. It is the enterprises that select industry structure, technology structure and trade structure according to dynamic alteration way of comparative technology structure and trade structure, which will ultimately promote evolution of economic growth gradually. So far as operational mechanism of service trade and investment is concerned, service trade affects factors supply in one country by physical capital accumulating effect, human capital effect, technology upgrade effect, institutional transition effect, employment effect and externality of technology, then influences the upgrade of industrial structure, the upgrade of technological structure and the transition of mode of economic growth. It is obvious that dynamic effect is greater than static effect; that external effect is playing more important role than internal effect; and that technology spillover effect of foreign direct investment in service industry is greater than that of service trade in a narrow sense (including across-border supply, consumption abroad and movement of natural person).For the research of mechanism about how service trade drive economic growth. Firstly, the paper verifies the causality between service trade and economic growths concerning different economic bodies and the representative countries. The results show that there are causalities between international service trade and economic growth in the whole world, in the developed countries, in the US and in china. In the developing countries, service trade is the Granger cause of economic growth; In the whole world and the developing countries, economic growth is the Granger cause of service trade; In the US, service export is the Granger cause of economic growth, and economic growth is the Granger cause of service import. On this basis, it is concluded that the opening of service industry will benefit economic growth in one country. Secondly, in order to explore on how the service trade and investment act on economic growth, empirical studies are employed to explain the case of US and that of China. The results show that the routes by which service trade affects economic growth in the US can be rowed as follows from more significant to less: employment effect, human capital effect, physical capital effect, technology effect, institution effect. The results of empirical analysis of China can be summarized that: the routes by which service export affects economic growth can be rowed as follows: employment effect, physical capital effect, institution effect, human capital effect, technology effect; the routs by which service import affectseconomic growth can be rowed as follows: technology effect, institution effect, employment effect, human capital effect, physical capital effect; the routes by which FDI in service affects economic growth can be rowed as follows: technology effect, human capital effect, institution effect, employment effect, physical capital effect. Moreover, the effect of FDI in service is stronger than service import, and the effect of service import is stronger than service export.According to the empirical test in this paper, the conclusion can be drawn as follows: service trade in a narrow sense will have static and dynamic effects on factor supply in one country through import and export of service, FDI in service industry is one of the most important cross-border transactions and is another important channel which will affect the transition of advantages on factor supply in one country. It should be emphasized that the above-mentioned channels will have different effects on countries at different stages of economic development. Whether the roles can be brought into play or not depends on given restraints. The input output of factors themselves cannot form a clear function, but will interact together and act on economic growth hand in hand through numerous feedback chain.Chinese economy is now undergoing transformation from elementary age to middle age of industrialization. Service trade and investment in current period have both advantages and disadvantages.Based on these judgments, we propose that China should pursue a policy favoring protectionism on management of service trade and adopt relevant countermeasures as follows. Scientific development view should be formed with an eye to harmonizing development of three industries so as to lay a solid industries foundation for service trade; The strategic programming should be stipulated and the market of service trade should be opened gradually; The rule of international transfer of service trade should be mastered and environment of utilizing foreign investment on service industry should be improved.As the characteristics of the world's service-oriented economy have gradually emerged, service trade originating from the upgrading of industrial structure has developed rapidly, and the scale of service trade is rapidly expanding. From the statistical data, the total exports of world service trade rose rapidly from 365 billion U.S. dollars in 1980 to 377.779 billion U.S. dollars in 2008, an increase of 9.35 times. Compared with the trade of goods with a long history, service trade is a new form of trade. With the continuous increase in absolute size and relatively low levels, service trade has become a focus of attention in modern society.2 The impact of overall service trade on economic growthAccording to the WTO General Agreement on Trade in Services (GA TS), which was signed in 1994, trade in services includes Cross- border Supply, Consumption A broad, Commercial Presence, and naturalperson mobility. (Movement of Natural Persn) Four modes. The service trade of these four modes has completely different properties and characteristics. Therefore, it is difficult to establish a unified theoretical framework for service trade to affect economic growth. The corresponding literature is very rare. The only foreign documents are mainly Robinson et al. (2002), who simply regard service trade as a commodity. Trade, without taking into account differences in the four trade models, studied the economic growth effects of service trade liberalization using the Computable General Equilibrium (CGE) model.Using empirical methods to study the literature on the impact of overall service trade on economic growth is more, but such studies are mostly domestic scholars. Research shows that the average contribution of China's overall service trade to economic growth is 18.9%.3 Effect of Service Trade in Different Industries on Economic GrowthAt present, the literature on the impact of industry trade in service trade on economic growth is mostly concentrated in such service sectors as finance, telecommunications, and health care. These studies have basically reached a relatively unanimous conclusion that the opening of the service sector or the increase in productivity can significantly promote economic growth. . For example, studies by Beck et al. (1998), M urinde & Ryan (2003), and Eschenbach (2004) suggest that the opening of the financial sector has, to a certain extent, broken the monopoly of domesticfinancial markets and prompted the orderly competition of financial markets. On the normal development track, productivity has improved, and it has finally led to economic growth in the country. Kim (2000) studied the relationship between the development of service trade in the distribution sector and the growth of total factor productivity (TFP) using Korea's input-output data. The results show that the liberalization of service trade not only significantly promoted its own TFP. The promotion also promoted the improvement of total factor productivity in the related manufacturing sector. The total factor productivity growth brought about by service trade almost covered the entire economic sector.4 Effect of Service Trade on Economic Growth by Different Trading ModesThere are few literatures on specific transaction models and theoretical studies on the impact of trade in services on economic growth. Carr et al. (2001) & M arkusen et al. (2005) theoretically examined the commercial existence model by means of the CGE model. The impact of the trade in services on economic growth shows that the opening up of trade in services is an important source of the increase in economic welfare of a country. From the perspective of economic welfare, the opening up of trade in services is a general trend. Subsequently, the use of CGE models to theoretically examine the impact of service trade on economic growth began to prevail. For example, Rutherford et al. (2005)used the CGE model to evaluate Russia's WTO accession effects, and Ko nan &Maskus (2006) used CGE models. The potential effects of Tunisia's elimination of barriers to trade in services were studied. Their conclusions indicate that the increase in the level of economic welfare in one country can benefit from the opening up of the service market, while the elimination of FDI market access barriers in the service sector is a pattern of four trades. The most important liberalization measures are the main sources of increased welfare in a country. There are a lot of literatures on the relationship between service trade and economic growth in specific models using empirical methods. In the four modes of trade in services, commercial presence is the most important one, and from the point of view of data availability, although statistical data is still not very accurate, commercial existence of service trade is based on service industry FDI as a carrier. To achieve this, researchers can use service industry FDI data to characterize the scale of service trade in this model, and this type of trade model has received more attention. Among them, Markusen (1989) believes that the existence of commercial trade in services has two positive and negative effects. The positive effect is that competition in the service sector has led to an increase in domestic demand for the sector’s production factors, which is conducive to output growth. The effect of market size and negative effects means that the intensified competition in the domestic market of service industries has led to the withdrawal ofdomestic service-oriented enterprises from the market. The study by Markusen (1989) shows that the effect of market size after the opening of the service market far exceeds the crowding-out effect. After offsetting the crowding-out effect, it can still promote the productivity improvement of the non-service sector and further lead to the structure of domestic trade in goods. The changes, those sectors that were previously low in productivity and dependent on imports, will evolve into high-productivity export sectors, which is quite similar to the latest research findings on the interactive development of producer services and manufacturing. Hoekman (2006) and Hoekman (2006) used India as an example to examine the impact of the existence of commercial trade in services in the finance, telecommunications, and transportation sectors on the competitiveness of the goods export sector, and believe that these sectors have been liberalized. The level of soft facilities has been increased, which in turn has greatly reduced the operating costs of the downstream product manufacturing sector, which has increased the export competitiveness. With the inefficiency of the domestic service industry, the unfavorable pattern is reversed with the help of commercial presence of service trade. Feasible choice. Guerrieri et al. (2005) took the EU as the research object and analyzed the role of commercial trade in services for knowledge accumulation and economic growth. The study concluded that the openness of the service market or the relaxation of domesticservice regulations has positively promoted economic growth. It was found that the imported service items may be more able to promote economic growth than the domestic same service items due to high technological content.5 Possible Future Research DirectionsIt is not difficult to find from the above-mentioned documents that since the development of service trade started late, research on the growth of service trade began to rise gradually from the 1980s, and more than 20 years of research in this area is in the ascendant. With the further enhancement of the status of trade in services, the possible directions for future research will generally include the following aspects.From the point of view of research methodology, classification of service trade can be studied. As the theory of goods trade has gradually matured, the development practice of service trade still calls for the birth of the theory of service trade. Helpman and Markusen, international economists, expressed on different occasions that the difficulty in establishing the theoretical system of service trade lies in the fact that there are large differences in various types of service trades, and it is difficult for researchers to overcome the gap between them. Classifying service trade according to certain standards and exploring the impact of various types of service trade on economic growth is a possible direction for future research.From the perspective of the research subjects, it is possible to study China’s service trade and economic growth. China’s GDP has already ranked second in the world. However, the service industry’s added value accounted for only 40% of GDP, which is obviously not commensurate with the status of an economic power. In addition, the trade in services is still relatively small compared to the trade in goods. Under such a realistic background, what is the relationship between China's service trade and economic growth? How will service trade contribute to China's economic growth? What impact will service outsourcing have on China's economy? With China in In the next decade, how will China make service trade an engine of economic growth? From the academic point of view, economists from all countries are paying attention to China’s economic development, and China’s service trade will also be improved. It will become a research hotspot.From the perspective of research topics, it is possible to study the impact of service outsourcing on economic growth. In 2008, the scale of global service outsourcing market has reached 1.5 trillion US dollars. According to the UNCTAD (UNCT AD) speculation, the global service outsourcing market will increase by 30%-40% in the next 5-10 years.The surging service industry outsourcing is a new form of service trade. How does service outsourcing drive economic growth through employment, industrial structure upgrading, and technology spillovers?What are the differences in the impact of contracting and receiving services on economic growth in the service industry? Research on these issues will start with the development of service outsourcing to important theoretical guidance.中文译文国际服务贸易与经济增长理论与实证研究Chakraborty Kavin1 引言国际贸易与经济增长始终是国际经济学最生动的论题之一。

外文文献及翻译

（（英文参考文献及译文）二〇一六年六月本科毕业论文题目：STATISTICAL SAMPLING METHOD, USED INTHE AUDIT学生姓名：王雪琴学院：管理学院系别：会计系专业：财务管理班级：财管12-2班学校代码： 10128 学号： 201210707016Statistics and AuditRomanian Statistical Review nr. 5 / 2010STATISTICAL SAMPLING METHOD, USED IN THE AUDIT - views, recommendations, fi ndingsPhD Candidate Gabriela-Felicia UNGUREANUAbstractThe rapid increase in the size of U.S. companies from the earlytwentieth century created the need for audit procedures based on the selectionof a part of the total population audited to obtain reliable audit evidence, tocharacterize the entire population consists of account balances or classes oftransactions. Sampling is not used only in audit – is used in sampling surveys,market analysis and medical research in which someone wants to reach aconclusion about a large number of data by examining only a part of thesedata. The difference is the “population” from which the sample is selected, iethat set of data which is intended to draw a conclusion. Audit sampling appliesonly to certain types of audit procedures.Key words: sampling, sample risk, population, sampling unit, tests ofcontrols, substantive procedures.Statistical samplingCommittee statistical sampling of American Institute of CertifiedPublic Accountants of (AICPA) issued in 1962 a special report, titled“Statistical sampling and independent auditors’ which allowed the use ofstatistical sampling method, in accordance with Generally Accepted AuditingStandards (GAAS). During 1962-1974, the AICPA published a series of paperson statistical sampling, “Auditor’s Approach to Statistical Sampling”, foruse in continuing professional education of accountants. During 1962-1974,the AICPA published a series of papers on statistical sampling, “Auditor’sApproach to Statistical Sampling”, for use in continuing professional educationof accountants. In 1981, AICPA issued the professional standard, “AuditSampling”, which provides general guidelines for both sampling methods,statistical and non-statistical.Earlier audits included checks of all transactions in the period coveredby the audited financial statements. At that time, the literature has not givenparticular attention to this subject. Only in 1971, an audit procedures programprinted in the “Federal Reserve Bulletin (Federal Bulletin Stocks)” includedseveral references to sampling such as selecting the “few items” of inventory.Statistics and Audit The program was developed by a special committee, which later became the AICPA, that of Certified Public Accountants American Institute.In the first decades of last century, the auditors often applied sampling, but sample size was not in related to the efficiency of internal control of the entity. In 1955, American Institute of Accountants has published a study case of extending the audit sampling, summarizing audit program developed by certified public accountants, to show why sampling is necessary to extend the audit. The study was important because is one of the leading journal on sampling which recognize a relationship of dependency between detail and reliability testing of internal control.In 1964, the AICPA’s Auditing Standards Board has issued a report entitled “The relationship between statistical sampling and Generally Accepted Auditing Standards (GAAS)” which illustrated the relationship between the accuracy and reliability in sampling and provisions of GAAS.In 1978, the AICPA published the work of Donald M. Roberts,“Statistical Auditing”which explains the underlying theory of statistical sampling in auditing.In 1981, AICPA issued the professional standard, named “Audit Sampling”, which provides guidelines for both sampling methods, statistical and non-statistical.An auditor does not rely solely on the results of a single procedure to reach a conclusion on an account balance, class of transactions or operational effectiveness of the controls. Rather, the audit findings are based on combined evidence from several sources, as a consequence of a number of different audit procedures. When an auditor selects a sample of a population, his objective is to obtain a representative sample, ie sample whose characteristics are identical with the population’s characteristics. This means that selected items are identical with those remaining outside the sample.In practice, auditors do not know for sure if a sample is representative, even after completion the test, but they “may increase the probability that a sample is representative by accuracy of activities made related to design, sample selection and evaluation” [1]. Lack of specificity of the sample results may be given by observation errors and sampling errors. Risks to produce these errors can be controlled.Observation error (risk of observation) appears when the audit test did not identify existing deviations in the sample or using an inadequate audit technique or by negligence of the auditor.Sampling error (sampling risk) is an inherent characteristic of the survey, which results from the fact that they tested only a fraction of the total population. Sampling error occurs due to the fact that it is possible for Revista Română de Statistică nr. 5 / 2010Statistics and Auditthe auditor to reach a conclusion, based on a sample that is different from the conclusion which would be reached if the entire population would have been subject to audit procedures identical. Sampling risk can be reduced by adjusting the sample size, depending on the size and population characteristics and using an appropriate method of selection. Increasing sample size will reduce the risk of sampling; a sample of the all population will present a null risk of sampling.Audit Sampling is a method of testing for gather sufficient and appropriate audit evidence, for the purposes of audit. The auditor may decide to apply audit sampling on an account balance or class of transactions. Sampling audit includes audit procedures to less than 100% of the items within an account balance or class of transactions, so all the sample able to be selected. Auditor is required to determine appropriate ways of selecting items for testing. Audit sampling can be used as a statistical approach and a non- statistical.Statistical sampling is a method by which the sample is made so that each unit consists of the total population has an equal probability of being included in the sample, method of sample selection is random, allowed to assess the results based on probability theory and risk quantification of sampling. Choosing the appropriate population make that auditor’ findings can be extended to the entire population.Non-statistical sampling is a method of sampling, when the auditor uses professional judgment to select elements of a sample. Since the purpose of sampling is to draw conclusions about the entire population, the auditor should select a representative sample by choosing sample units which have characteristics typical of that population. Results will not extrapolate the entire population as the sample selected is representative.Audit tests can be applied on the all elements of the population, where is a small population or on an unrepresentative sample, where the auditor knows the particularities of the population to be tested and is able to identify a small number of items of interest to audit. If the sample has not similar characteristics for the elements of the entire population, the errors found in the tested sample can not extrapolate.Decision of statistical or non-statistical approach depends on the auditor’s professional judgment which seeking sufficient appropriate audits evidence on which to completion its findings about the audit opinion.As a statistical sampling method refer to the random selection that any possible combination of elements of the community is equally likely to enter the sample. Simple random sampling is used when stratification was not to audit. Using random selection involves using random numbers generated byRomanian Statistical Review nr. 5 / 2010Statistics and Audit a computer. After selecting a random starting point, the auditor found the first random number that falls within the test document numbers. Only when the approach has the characteristics of statistical sampling, statistical assessments of risk are valid sampling.In another variant of the sampling probability, namely the systematic selection (also called random mechanical) elements naturally succeed in office space or time; the auditor has a preliminary listing of the population and made the decision on sample size. “The auditor calculated a counting step, and selects the sample element method based on step size. Step counting is determined by dividing the volume of the community to sample the number of units desired. Advantages of systematic screening are its usability. In most cases, a systematic sample can be extracted quickly and method automatically arranges numbers in successive series.”[2].Selection by probability proportional to size - is a method which emphasizes those population units’recorded higher values. The sample is constituted so that the probability of selecting any given element of the population is equal to the recorded value of the item;Stratifi ed selection - is a method of emphasis of units with higher values and is registered in the stratification of the population in subpopulations. Stratification provides a complete picture of the auditor, when population (data table to be analyzed) is not homogeneous. In this case, the auditor stratifies a population by dividing them into distinct subpopulations, which have common characteristics, pre-defined. “The objective of stratification is to reduce the variability of elements in each layer and therefore allow a reduction in sample size without a proportionate increase in the risk of sampling.” [3] If population stratification is done properly, the amount of sample size to come layers will be less than the sample size that would be obtained at the same level of risk given sample with a sample extracted from the entire population. Audit results applied to a layer can be designed only on items that are part of that layer.I appreciated as useful some views on non-statistical sampling methods, which implies that guided the selection of the sample selecting each element according to certain criteria determined by the auditor. The method is subjective; because the auditor selects intentionally items containing set features him.The selection of the series is done by selecting multiple elements series (successive). Using sampling the series is recommended only if a reasonable number of sets used. Using just a few series there is a risk that the sample is not representative. This type of sampling can be used in addition to other samples, where there is a high probability of occurrence of errors. At the arbitrary selection, no items are selected preferably from the auditor, Revista Română de Statistică nr. 5 / 2010Statistics and Auditthat regardless of size or source or characteristics. Is not the recommended method, because is not objective.That sampling is based on the auditor’s professional judgment, which may decide which items can be part or not sampled. Because is not a statistical method, it can not calculate the standard error. Although the sample structure can be constructed to reproduce the population, there is no guarantee that the sample is representative. If omitted a feature that would be relevant in a particular situation, the sample is not representative.Sampling applies when the auditor plans to make conclusions about population, based on a selection. The auditor considers the audit program and determines audit procedures which may apply random research. Sampling is used by auditors an internal control systems testing, and substantive testing of operations. The general objectives of tests of control system and operations substantive tests are to verify the application of pre-defined control procedures, and to determine whether operations contain material errors.Control tests are intended to provide evidence of operational efficiency and controls design or operation of a control system to prevent or detect material misstatements in financial statements. Control tests are necessary if the auditor plans to assess control risk for assertions of management.Controls are generally expected to be similarly applied to all transactions covered by the records, regardless of transaction value. Therefore, if the auditor uses sampling, it is not advisable to select only high value transactions. Samples must be chosen so as to be representative population sample.An auditor must be aware that an entity may change a special control during the course of the audit. If the control is replaced by another, which is designed to achieve the same specific objective, the auditor must decide whether to design a sample of all transactions made during or just a sample of transactions controlled again. Appropriate decision depends on the overall objective of the audit test.Verification of internal control system of an entity is intended to provide guidance on the identification of relevant controls and design evaluation tests of controls.Other tests:In testing internal control system and testing operations, audit sample is used to estimate the proportion of elements of a population containing a characteristic or attribute analysis. This proportion is called the frequency of occurrence or percentage of deviation and is equal to the ratio of elements containing attribute specific and total number of population elements. WeightRomanian Statistical Review nr. 5 / 2010Statistics and Audit deviations in a sample are determined to calculate an estimate of the proportion of the total population deviations.Risk associated with sampling - refers to a sample selection which can not be representative of the population tested. In other words, the sample itself may contain material errors or deviations from the line. However, issuing a conclusion based on a sample may be different from the conclusion which would be reached if the entire population would be subject to audit.Types of risk associated with sampling:Controls are more effective than they actually are or that there are not significant errors when they exist - which means an inappropriate audit opinion. Controls are less effective than they actually are that there are significant errors when in fact they are not - this calls for additional activities to establish that initial conclusions were incorrect.Attributes testing - the auditor should be defining the characteristics to test and conditions for misconduct. Attributes testing will make when required objective statistical projections on various characteristics of the population. The auditor may decide to select items from a population based on its knowledge about the entity and its environment control based on risk analysis and the specific characteristics of the population to be tested.Population is the mass of data on which the auditor wishes to generalize the findings obtained on a sample. Population will be defined compliance audit objectives and will be complete and consistent, because results of the sample can be designed only for the population from which the sample was selected.Sampling unit - a unit of sampling may be, for example, an invoice, an entry or a line item. Each sample unit is an element of the population. The auditor will define the sampling unit based on its compliance with the objectives of audit tests.Sample size - to determine the sample size should be considered whether sampling risk is reduced to an acceptable minimum level. Sample size is affected by the risk associated with sampling that the auditor is willing to accept it. The risk that the auditor is willing to accept lower, the sample will be higher.Error - for detailed testing, the auditor should project monetary errors found in the sample population and should take into account the projected error on the specific objective of the audit and other audit areas. The auditor projects the total error on the population to get a broad perspective on the size of the error and comparing it with tolerable error.For detailed testing, tolerable error is tolerable and misrepresentations Revista Română de Statistică nr. 5 / 2010Statistics and Auditwill be a value less than or equal to materiality used by the auditor for the individual classes of transactions or balances audited. If a class of transactions or account balances has been divided into layers error is designed separately for each layer. Design errors and inconsistent errors for each stratum are then combined when considering the possible effect on the total classes of transactions and account balances.Evaluation of sample results - the auditor should evaluate the sample results to determine whether assessing relevant characteristics of the population is confirmed or needs to be revised.When testing controls, an unexpectedly high rate of sample error may lead to an increase in the risk assessment of significant misrepresentation unless it obtained additional audit evidence to support the initial assessment. For control tests, an error is a deviation from the performance of control procedures prescribed. The auditor should obtain evidence about the nature and extent of any significant changes in internal control system, including the staff establishment.If significant changes occur, the auditor should review the understanding of internal control environment and consider testing the controls changed. Alternatively, the auditor may consider performing substantive analytical procedures or tests of details covering the audit period.In some cases, the auditor might not need to wait until the end audit to form a conclusion about the effectiveness of operational control, to support the control risk assessment. In this case, the auditor might decide to modify the planned substantive tests accordingly.If testing details, an unexpectedly large amount of error in a sample may cause the auditor to believe that a class of transactions or account balances is given significantly wrong in the absence of additional audit evidence to show that there are not material misrepresentations.When the best estimate of error is very close to the tolerable error, the auditor recognizes the risk that another sample have different best estimate that could exceed the tolerable error.ConclusionsFollowing analysis of sampling methods conclude that all methods have advantages and disadvantages. But the auditor is important in choosing the sampling method is based on professional judgment and take into account the cost / benefit ratio. Thus, if a sampling method proves to be costly auditor should seek the most efficient method in view of the main and specific objectives of the audit.Romanian Statistical Review nr. 5 / 2010Statistics and Audit The auditor should evaluate the sample results to determine whether the preliminary assessment of relevant characteristics of the population must be confirmed or revised. If the evaluation sample results indicate that the relevant characteristics of the population needs assessment review, the auditor may: require management to investigate identified errors and likelihood of future errors and make necessary adjustments to change the nature, timing and extent of further procedures to take into account the effect on the audit report.Selective bibliography:[1] Law no. 672/2002 updated, on public internal audit[2] Arens, A şi Loebbecke J - Controve …Audit– An integrate approach”, 8th edition, Arc Publishing House[3] ISA 530 - Financial Audit 2008 - International Standards on Auditing, IRECSON Publishing House, 2009- Dictionary of macroeconomics, Ed C.H. Beck, Bucharest, 2008Revista Română de Statistică nr. 5 / 2010Statistics and Audit摘要美国公司的规模迅速增加，从第二十世纪初创造了必要的审计程序，根据选定的部分总人口的审计，以获得可靠的审计证据，以描述整个人口组成的帐户余额或类别的交易。

国际贸易对碳排放的影响外文文献翻译中英文

外文文献翻译(含：英文原文及中文译文)英文原文The effects of international trade on Chinese carbon emissionsB Wei ，X Fang ，Y WangAbstractInternational trade is an important impact factor to the carbon emissions of a country. As the rapid development of Chinese foreign trade since its entry into the WTO in 2002, the effects of international trade on carbon emissions of China are more and more significant. Using the recent available input-output tables of China and energy consumption data, this study estimated the effects of Chinese foreign trade on carbon emissions and the changes of the effects by analyzing the emissions embodied in trade between 2002 and 2007. The results showed a more and more significant exporting behavior of embodied carbon emissions in Chinese international trade. From 2002 to 2007, the proportion of net exported emissions and domestic exported emissions in domestic emissions increased from 18.32% to 29.79% and from 23.97% to 34.76%, respectively. In addition, about 22.10% and 32.29% of the total imported emissions were generated in processing trade in 2002 and 2007, respectively, which were imported and later exported emissions. Although, most of the sectors showed a growth trend in imported and exportedemissions, sectors of electrical machinery and communication electronic equipment, chemical industry, and textile were still the biggest emission exporters, the net exported emissions of which were also the largest. For China and other developing countries, technology improvement may be the most favorable and acceptable ways to reduce carbon emissions at present stage. In the future negotiations on emissions reduction, it would be more fair and reasonable to include the carbon emissions embodied in international trade when accounting the total emissions of an economy. Keywords: input-output analysis, carbon emissions, international trade, ChinaIntroductionGlobal warming has been considered an indisputable fact. The main reason is that the warming of the global climate system is due to the continuous increase in the concentration of greenhouse gases in the atmosphere, the result of human activities (IPCC, 2007). In order to avoid the possible negative impact on human society's global warming, a series of measures have been taken to reduce global greenhouse gas emissions to slow down global warming. However, around the CO2 emission reduction and the future allocation of carbon emission rights, the game plays a different interest group.With the development of globalization, the impact on the international trade of the environment is becoming more and moresignificant, including the potential impact of carbon emissions from geographical relocation. Many researchers estimate that it is reflected in international trade in certain countries as well as in the world economy (Wykoff and Rupp, carbon emissions in 1994; Schaefer and Lealdesa, 1996, Machado et al., 2001 Year; Munksgaard, Peder and Sen, 2001; Ahmed and Wykov, 2003; Sanchez-Chóliz and Duarte, 2004; Peters and Hess, 2006, 2008; Mäenpää et al, 2007; Keman et al., 2007). The general conclusion is that in a more open economy, the impact of large foreign trade on the carbon emissions of a country. In addition, all these studies have pointed out that import and export trade cannot ignore a relatively open economy; otherwise, energy and carbon emissions figures may be seriously distorted by this economy (Machado et al., 2001). In terms of total volume, the value of China’s trade surplus increased from US$30.43 billion in 2002 to US$261.83 billion in 2007 (National Bureau of Statistics, 2008). The rapid growth of China’s foreign trade will have a significant effect on China’s carbon emissions.As one of the countries with the highest carbon emissions, China is facing increasing pressure to reduce emissions. However, China is also a big country in international trade. The rapid development of China’s economy has led to steady growth in foreign trade. From 1997 to 2002, China’s total import and export value increased by an average annual growth rate of 14.35%. Since joining the World Trade Organization, theaverage annual growth rate of China’s trade has jumped to 28.64%. From 2002 to 2007, the value of exports compared with 2002, it increased by 2.7 times in 2007 to reach US$1.2177.8 billion. Imports also soared to US$955.95 billion in 2007, which was 2.2 times higher than the 2002 imports. In terms of total volume, the value of China’s trade surplus increased from US$30.43 billion in 2002 to US$261.83 billion in 2007 (National Bureau of Statistics, 2008). The rapid growth of China’s foreign trade will have a significant effect on China’s carbon emissions.However, quantitative assessment of the impact of China's international trade in energy use and carbon emissions has only recently begun. Estimates from the IEA (2007) show that China's domestic production and export of energy-related carbon dioxide emissions account for 34% of total emissions, and if it is used in 2004, the weighted average carbon intensity of commodity countries imported from China is estimated. China's net exports of EM-rich CO2 may be more than 17% of total emissions in 2004 (Levin, 2008). Using a single-area input-output model, Pan et al. (2008) estimated that their production of energy and emissions in 2002 accounted for 16% and 19% of China’s net exports of primary energy consumption, respectively, in 2002. In the input-output analysis, China reported that the discharge volume of pre-grid discharges to the United States accounted for about 5%. Weber et al. (2008), ESTI mating production exported from China's carbon dioxide emissions from1987 to 2005. In 2005, about one-third of China's emissions were due to production exports, and this proportion has risen from 12% in 1987 to 21% in 2002. In developed countries, consumption is driving this trend. Wei et al.'s estimation (2009a) also found that the presence of emissions in China's economy in 2002 reflected significant export behavior; in addition, subsequent exports (processing trade played by EMIS--) were total imports of 20 %the above. In addition, using a multi-area input-output model, Peters and Hewei (2008) also found that export emissions represented 24.4% of China's domestic emissions, and the proportion of imports in 2001 was only 6.6%. A similar study by Atkinson et al. (2009) also shows that China is a net exporter of carbon emissions in international trade. In recent years, using ecological input-output based on physical access programs, MOD-Y eling, Chen and Chen (2010) estimated that in 2007 China's export of carbon dioxide emissions and total energy were respectively 32.31% and 33.65% of total emissions.Both the United States and European countries are major importers of China’s export carbon emissions. Using the economic input-output life cycle assessment software, Ruihe Harris (2006) found that about 7% of China’s carbon dioxide emissions from exports to the United States during the period of 1997-2003 were produced by 14% of the total; the US’s CO2 emissions will At 3%-6%, if increased imports from Chinahave been produced in the United States. AP-walking a similar approach, Lee Hewitt found that bilateral trade between the United Kingdom and China (2008) produced about 4% of CO2 emissions. In 2004, China's CO2 emissions were for the UK market to produce goods and the UK trade decreased. About 11%. Weber et al. (2008) also found that most of China’s recent export emissions went to developed countries, approximately 27% of the United States, 19% of the EU-27, and 14% of the remaining Annex B countries, mainly Japan and Australia. And New Zealand. Recently, Xu et al. (2009) studied the impact of energy consumption and exhaust emissions on the environment. From 2002 to 2007, the use of environmental input-output analysis and adjustment of bilateral trade data reflected trade in the East (from China to the United States). Zhang (2009) has also obtained similar results. Energy and CO2 account for about 12% and 17% of China's energy consumption, and China's CO2 emissions are 8% and 12%, respectively.Although China's international trade is a meaningful research on carbon emissions, further related research is necessary because of the rapid development of China's foreign trade, especially the development of processing trade. According to statistics (National Bureau of Statistics, 2008), the export share of processing trade has been more than 50% of total exports since 1996. In 2002 and 2007, the share of processing trade reached 55.26% and 50.71%, which will be processing trade. Thenecessary distinction between the impact of general trade and China's carbon emissions.Since China's input-output table is only 5 years, we have chosen from 2002 (entry to the WTO) to 2007 (the latest issue), and China's international trade input-output table has impact on carbon emissions with the view of the last requirement of this paper. Influence changes. In addition, we distinguish between domestic processing trade and import investment in the assessment of production processes (import emissions and re-exports), which will help us to further understand the impact of international trade on emissions status. In this study, we tried to answer three questions: 1) What is the net emissions generated by foreign trade in China as a big country's foreign trade? 2) China from 2002 to 2007, International How does trade affect carbon emissions? 3) From 2002 to 2007, which departments were the major emitters of China's import and export trade and their roles?Uncertainty in the calculation of carbon emissionsThe calculation of emissions from China's trade reflects a certain degree of uncertainty. One is that the input-output analysis itself has many inherent uncertainties (more discussion in Lenzen, 2001). Based on an input-output table for China's single region, it allows us to obtain a relatively accurate assessment of the emissions that are reflected in China's exports, but this error may be more pronounced when estimatingthe emissions of goods and services exported to China. (Lenzen , 2001; Lenzen et al., 2004). Another important factor of uncertainty is that the calculations come from different regions, which may underestimate the method of importing the carbon intensity factor that is reflected in the import of larger proportion of finished product producing countries and tertiary industries, and the smaller proportion of secondary industries. In addition, the method of pro-grade introduction of the column will inevitably result in some errors in order to obtain a matrix from the inlet of the original import and export table.At present, for reasons of data availability, we cannot fully quantify the accuracy of our calculations, but preliminary estimates suggest that the use of more accurate data results from research will not significantly change the conclusions of this analysis. These restrictions will be improved through the use of multi-zone import and export tables and out-of-zone more detailed industry carbon intensity and sector-to-sector production processes in the future for detailed analysis.Understand the impact of international trade on carbon emissions in ChinaFrom 2002 to 2007, the impact of foreign trade on China’s carbon emissions has greatly expanded. It may be largely related to two factors. The first is the coal-based energy consumption structure. The secondary industry-based production structure will maintain high domestic energyintensity. In 2002, the coal consumption exchange was only 66.3% of the total energy consumption. The 44.8% of China's gross domestic product (GDP) is due to the secondary industry in 2002 (National Bureau of Statistics, 2008). In 2007, related stock prices rose as high as 69.5% and 48.6%, respectively, which will lead to the fact that the unit exports are higher than the carbon emissions reflected in unit imports. The second factor, which may be a more important factor, is the rapid growth of export trade. From 2002 to 2007, China’s exports increased by 246.80%, while imports increased by 199.97% (National Bureau of Statistics, 2008). Export growth is significantly higher than imports, which may lead to a sharp increase in net exports. Decomposition analysis using input and output structures, Liu et al. (2010) also found that the total export expansion of export and energy-intensive products tends to expand, reflecting the export of energy from 1992 to 2005, but the improvement and change of energy efficiency in the primary energy consumption structure can offset part of the impact on export energy. The above driving force is implemented.Although, based on the coal-based energy consumption structure, the carbon dioxide emissions produced by the secondary industry-based production structure, the more important role, it may be difficult for China to adjust because of its endowment characteristics, and in a very short time Its structural characteristics and its current economicdevelop ment stage. In addition, the expansion of China’s foreign trade, including the expansion of the trade surplus, is mainly the result of the market economy’s maximizing its comparative advantage. The development-replacement of China's economy not only provided many of the world's goods and services, but also reduced the nation's production-based relative costs in developed countries. China’s foreign trade has always played an important role in the development of the world economy, due to its huge market, stable government system and abundant cheap labor. Therefore, it can be argued that at the current stage, for China's better methods to reduce the impact of international trade on national or global CO2 emissions should be to improve its production technology, reduce the intensity of energy consumption as a whole, not only to control China The amount of foreign trade. In addition, the imported goods from China should take part in China's carbon emission responsibilities, because the CON-consumer demand of foreign consumers has generated a large amount of China's carbon emissions, especially for consumers in developed countries.ConclusionDespite some uncertainties in this study, most areas produced from the details of the data, we can conclude that international trade has a significant impact on China's carbon emissions, and changed the impact of time on going. Compared with 2002 emissions, domestic exportemissions in 2007 increased from 267.07 MTC to 718.31 MTC, with a speed increase of over 160%; net exports also increased correspondingly, from 204.08 MTC up to 615.65 MTC, over 200% growth rate Now. From 23.97% in 2002, the share of domestic emissions from domestic emissions jumped to 34.76% in 2007. The share of pre-net transplants that exceeded domestic emissions also rose from 18.32% in 2002 to 29.79% in 2007. The results show that more and more significant net export behaviors of implied carbon emissions exist in China's economy and processing trade have more and more significant effects on carbon emissions.Regardless of the emissions of imported emissions or exports, most industries showed a growth trend in 2007. Compared with 2002, emissions although the sectoral emissions have changed for the entire economy from 2002 to 2002, The impact, of which the largest percentage of imported major department or China's export emissions remain unchanged. The largest import emissions (all or actual imports) come from the industries of electrical machinery and communications electronics, chemicals, smelting and rolling plus metals. Electrical machinery and communications electronics equipment, chemicals, textiles and other sectors are the largest emitters of exports, net exports of which are also the largest. Technological progress may be the most favorable and acceptable way for China and other developing countries toreduce their carbon emissions. Considering that the world’s largest carbon emissions and the recent increase in emissions are in developing countries, the historical responsibility for the current responsibilities, developed countries should also take more efforts to help developing countries reduce their carbon emissions. Economic growth through technical assistance And financial support. In the car's list of future emissions reductions, which include the total economic output, the carbon emissions reflected in international trade will be fair and reasonable.中文译文国际贸易对中国碳排放的影响: 一份具有经验性的分析作者：B Wei ，X Fang ，Y Wang摘要国际贸易是一个国家碳排放量重要的影响因素,自2002年加入世贸组织,中国对外贸易的快速发展对碳排放的影响越来越显著。

建筑防火中英文对照外文翻译文献

- 1 -中英文对照外文翻译(文档含英文原文和中文翻译)外文文献外文文献: :Designing Against Fire Of BulidingABSTRACT:This paper considers the design of buildings for fire safety. It is found that fire and the associ- ated effects on buildings is significantly different to other forms of loading such as gravity live loads, wind and earthquakes and their respective effects on the building structure. Fire events are derived from the human activities within buildings or from the malfunction of mechanical and electrical equipment provided within buildings to achieve a serviceable environment. It is therefore possible to directly influence the rate of fire starts within buildings by changing human behaviour, improved maintenance and improved design of mechanical and electricalsystems. Furthermore, should a fire develops, it is possible to directly influence the resulting fire severity by the incorporation of fire safety systems such as sprinklers and to provide measures within the building to enable safer egress from the building. The ability to influence the rate of fire starts and the resulting fire severity is unique to the consideration of fire within buildings since other loads such as wind and earthquakes are directly a function of nature. The possible approaches for designing a building for fire safety are presented using an example of a multi-storey building constructed over a railway line. The design of both the transfer structure supporting the building over the railway and the levels above the transfer structure are consideredin the context of current regulatory requirements. The principles and assumptions associ- ated with various approaches are discussed.1 INTRODUCTIONOther papers presented in this series consider the design of buildings for gravity loads, wind and earthquakes.The design of buildings against such load effects is to a large extent covered by engineering based standards referenced by the building regulations. This is not the case, to nearly the same extent, in the case of fire. Rather, it is building regulations such as the Building Code of Australia (BCA) that directly specify most of the requirements for fire safety of buildings with reference being made to Standards such as AS3600 or AS4100 for methods for determining the fire resistance of structural elements.The purpose of this paper is to consider the design of buildings for fire safety from an engineering perspective (as is currently done for other loads such as wind or earthquakes), whilst at the same time,putting such approaches in the context of the current regulatory requirements.At the outset,it needs to be noted that designing a building for fire safety is far more than simply considering the building structure and whether it has sufficient structural adequacy.This is because fires can have a direct influence on occupants via smoke and heat and can grow in size and severity unlike other effects imposed on the building. Notwithstanding these comments, the focus of this paper will be largely on design issues associated with the building structure.Two situations associated with a building are used for the purpose of discussion. The multi-storey office building shown in Figure 1 is supported by a transfer structure that spans over a set of railway tracks. It is assumed that a wide range of rail traffic utilises these tracks including freight and diesel locomotives. The first situation to be considered from a fire safety perspective is the transfer structure.This is termed Situation 1 and the key questions are: what level of fire resistance is required for this transfer structure and how can this be determined? This situation has been chosen since it clearly falls outside the normal regulatory scope of most build-ing regulations. An engineering solution, rather than a prescriptive one is required. The second fire situation (termed Situation 2) corresponds to a fire within the office levels of the building and is covered by building regulations. This situation is chosen because it will enable a discussion of engineering approaches and how these interface with the building regulations regulations––since both engineering and prescriptive solutions are possible.2 UNIQUENESS OF FIRE2.1 Introduction Wind and earthquakes can be considered to b Wind and earthquakes can be considered to be “natural” phenomena o e “natural” phenomena o e “natural” phenomena over which designers ver which designers have no control except perhaps to choose the location of buildings more carefully on the basis of historical records and to design building to resist sufficiently high loads or accelerations for the particular location. Dead and live loads in buildings are the result of gravity. All of these loads are variable and it is possible (although generally unlikely) that the loads may exceed the resistance of the critical structural members resulting in structural failure.The nature and influence of fires in buildings are quite different to those associated with other“loads” to which a building may be subjected to. The essential differences are described in the following sections.2.2 Origin of FireIn most situations (ignoring bush fires), fire originates from human activities within the building or the malfunction of equipment placed within the building to provide a serviceable environment. It follows therefore that it is possible to influence the rate of fire starts by influencing human behaviour, limiting and monitoring human behaviour and improving the design of equipment and its maintenance. This is not the case for the usual loads applied to a building.2.3 Ability to InfluenceSince wind and earthquake are directly functions of nature, it is not possible to influence such events to any extent. One has to anticipate them and design accordingly. It may be possibleto influence the level of live load in a building by conducting audits and placing restrictions on contents. However, in the case of a fire start, there are many factors that can be brought to bear to influence the ultimate size of the fire and its effect within the building. It is known that occupants within a building will often detect a fire and deal with it before it reaches a sig- nificant size. It is estimated that less than one fire in five (Favre, 1996) results in a call to the fire brigade and for fires reported to the fire brigade, the majority will be limited to the room of fire origin. Inoc- cupied spaces, olfactory cues (smell) provide powerful evidence of the presence of even a small fire. The addition of a functional smoke detection system will further improve the likelihood of detection and of action being taken by the occupants.Fire fighting equipment, such as extinguishers and hose reels, is generally provided within buildings for the use of occupants and many organisations provide training for staff in respect ofthe use of such equipment.The growth of a fire can also be limited by automatic extinguishing systems such as sprinklers, which can be designed to have high levels of effectiveness.Fires can also be limited by the fire brigade depending on the size and location of the fire at the time of arrival.2.4 Effects of FireThe structural elements in the vicinity of the fire will experience the effects of heat. The temperatures within the structural elements will increase with time of exposure to the fire, the rate of temperature rise being dictated by the thermal resistance of the structural element and the severity of the fire. The increase in temperatures within a member will result in both thermal expansion and,eventually,a reduction in the structural resistance of the member. Differential thermal expansion will lead to bowing of a member. Significant axial expansion willbe accommodated in steel members by either overall or local buckling or yielding of local- ised regions. These effects will be detrimental for columns but for beams forming part of a floorsystem may assist in the development of other load resisting mechanisms (see Section 4.3.5).With the exception of the development of forces due to restraint of thermal expansion, fire does not impose loads on the structure but rather reduces stiffness and strength. Such effects are not instantaneous but are a function of time and this is different to the effects of loads such as earthquake and wind that are more or less instantaneous.Heating effects associated with a fire will not be significant or the rate of loss of capacity will be slowed if:(a) the fire is extinguished (e.g. an effective sprinkler system)(b) the fire is of insufficient severity –– insufficient fuel, and/or(b) the fire is of insufficient severity(c)the structural elements have sufficient thermal mass and/or insulation to slow the rise in internal temperatureFire protection measures such as providing sufficient axis distance and dimensions for concrete elements, and sufficient insulation thickness for steel elements are examples of (c). These are illustrated in Figure 2.The two situations described in the introduction are now considered.3 FIRE WITHIN BUILDINGS3.1 Fire Safety ConsiderationsThe implications of fire within the occupied parts of the office building (Figure 1) (Situation 2) are now considered. Fire statistics for office buildings show that about one fatality is expected in an office building for every 1000 fires reported to the fire brigade. This is an orderof magnitude less than the fatality rate associated with apartment buildings. More than two thirdsof fires occur during occupied hours and this is due to the greater human activity and the greater use of services within the building. It is twice as likely that a fire that commences out of normal working hours will extend beyond the enclosure of fire origin.A relatively small fire can generate large quantities of smoke within the floor of fire origin.If the floor is of open-plan construction with few partitions, the presence of a fire during normal occupied hours is almost certain to be detected through the observation of smoke on the floor. The presence of full height partitions across the floor will slow the spread of smoke and possibly also the speed at which the occupants detect the fire. Any measures aimed at improving housekeeping, fire awareness and fire response will be beneficial in reducing the likelihood of major fires during occupied hours.For multi-storey buildings, smoke detection systems and alarms are often provided to give “automatic” detection and warning to the occupants. An alarm signal is also transm itted to the fire brigade.Should the fire not be able to be controlled by the occupants on the fire floor, they will need to leave the floor of fire origin via the stairs. Stair enclosures may be designed to be fire-resistant but this may not be sufficient to keep the smoke out of the stairs. Many buildings incorporate stair pressurisation systems whereby positive airflow is introduced into the stairs upon detection of smoke within the building. However, this increases the forces required to open the stair doors and makes it increasingly difficult to access the stairs. It is quite likely that excessive door opening forces will exist(Fazio et al,2006)From a fire perspective, it is common to consider that a building consists of enclosures formed by the presence of walls and floors.An enclosure that has sufficiently fire-resistant boundaries (i.e. walls and floors) is considered to constitute a fire compartment and to be capableof limiting the spread of fire to an adjacent compartment. However, the ability of such boundariesto restrict the spread of fire can be severely limited by the need to provide natural lighting (windows)and access openings between the adjacent compartments (doors and stairs). Fire spread via the external openings (windows) is a distinct possibility given a fully developed fire. Limit- ing the window sizes and geometry can reduce but not eliminate the possibility of vertical fire spread.By far the most effective measure in limiting fire spread, other than the presence of occupants, is an effective sprinkler system that delivers water to a growing fire rapidly reducing the heat being generated and virtually extinguishing it.3.2 Estimating Fire SeverityIn the absence of measures to extinguish developing fires, or should such systems fail; severe fires can develop within buildings.In fire engineering literature, the term “fire load” refers to the quantity of combustibles within an enclosure and not the loads (forces) applied to the structure during a fire. Similarly, fire load density refers to the quantity of fuel per unit area. It is normally expressed in terms of MJ/m2or kg/m 2of wood equivalent. Surveys of combustibles for various occupancies (i.e offices, retail,hospitals, warehouses, etc)have been undertaken and a good summary of the available data is given in FCRC (1999). As would be expected, the fire load density is highly variable. Publications such as the International Fire Engineering Guidelines (2005) give fire load data in terms of the mean and 80th percentile.The latter level of fire load density is sometimes taken asthe characteristic fire load density and is sometimes taken as being distributed according to a Gumbel distribution (Schleich et al, 1999).The rate at which heat is released within an enclosure is termed the heat release rate (HRR) and normally expressed in megawatts (MW). The application of sufficient heat to a combustible material results in the generation of gases some of which are combustible. This process is called pyrolisation.Upon coming into contact with sufficient oxygen these gases ignite generating heat. The rate of burning(and therefore of heat generation) is therefore dependent on the flow of air to the gases generated by the pyrolising fuel.This flow is influenced by the shape of the enclosure (aspect ratio), and the position and size of any potential openings. It is found from experiments with single openings in approximately cubic enclosures that the rate of burning is directly proportional to A h where A is the area of the opening and h is the opening height. It is known that for deep enclosures with single openings that burning will occur initially closest to the opening moving back into the enclosure once the fuel closest to the opening is consumed (Thomas et al, 2005). Significant temperature variations throughout such enclosures can be expected.The use of the word ‘opening’ in relation to real building enclosures refers to any openings present around the walls including doors that are left open and any windows containing non fire-resistant glass.It is presumed that such glass breaks in the event of development of a significant fire. If the windows could be prevented from breaking and other sources of air to the enclosure limited, then the fire would be prevented from becoming a severe fire.V arious methods have been developed for determining the potential severity of a fire within an enclosure.These are described in SFPE (2004). The predictions of these methods are variable and are mostly based on estimating a representative heat release rate (HRR) and the proportion of total fuel ς likely to be consumed during the primary burning stage (Figure 4). Further studies of enclosure fires are required to assist with the development of improved models,as the behaviour is very complex.3.3 Role of the Building StructureIf the design objectives are to provide an adequate level of safety for the occupants and protection of adjacent properties from damage, then the structural adequacy of the building in fire need only be sufficient to allow the occupants to exit the building and for the building to ultimately deform in a way that does not lead to damage or fire spread to a building located on an adjacent site.These objectives are those associated with most building regulations including the Building Code of Australia (BCA). There could be other objectives including protection of the building against significant damage. In considering these various objectives, the following should be taken into account when considering the fire resistance of the building structure.3.3.1 Non-Structural ConsequencesSince fire can produce smoke and flame, it is important to ask whether these outcomes will threaten life safety within other parts of the building before the building is compromised by a lossof structural adequacy? Is search and rescue by the fire brigade not feasible given the likely extent of smoke? Will the loss of use of the building due to a severe fire result in major property and income loss? If the answer to these questions is in the affirmative, then it may be necessary to minimise the occurrence of a significant fire rather than simply assuming that the building structure needs to be designed for high levels of fire resistance. A low-rise shopping centre with levels interconnected by large voids is an example of such a situation.3.3.2 Other Fire Safety SystemsThe presence of other systems (e.g. sprinklers) within the building to minimise the occurrence of a serious fire can greatly reduce the need for the structural elements to have high levels of fire resistance. In this regard, the uncertainties of all fire-safety systems need to be considered. Irrespective of whether the fire safety system is the sprinkler system, stair pressurisation, compartmentation or the system giving the structure a fire-resistance level (e.g. concrete cover), there is an uncertainty of performance. Uncertainty data is available for sprinkler systems(because it is relatively easy to collect) but is not readily available for the other fire safety systems. This sometimes results in the designers and building regulators considering that only sprinkler systems are subject to uncertainty. In reality, it would appear that sprinklers systems have a high level of performance and can be designed to have very high levels of reliability.3.3.3 Height of BuildingIt takes longer for a tall building to be evacuated than a short building and therefore the structure of a tall building may need to have a higher level of fire resistance. The implications of collapse of tall buildings on adjacent properties are also greater than for buildings of only several storeys.3.3.4 Limited Extent of BurningIf the likely extent of burning is small in comparison with the plan area of the building, then the fire cannot have a significant impact on the overall stability of the building structure. Examples of situations where this is the case are open-deck carparks and very large area building such as shopping complexes where the fire-effected part is likely to be small in relation to area of the building floor plan.3.3.5 Behaviour of Floor ElementsThe effect of real fires on composite and concrete floors continues to be a subject of much research.Experimental testing at Cardington demonstrated that when parts of a composite floor are subject to heating, large displacement behaviour can develop that greatly assists the load carrying capacity of the floor beyond that which would predicted by considering only the behaviour of the beams and slabs in isolation.These situations have been analysed by both yield line methods that take into account the effects of membrane forces (Bailey, 2004) and finite element techniques. In essence, the methods illustrate that it is not necessary to insulate all structural steel elements in a composite floor to achieve high levels of fire resistance.This work also demonstrated that exposure of a composite floor having unprotected steel beams, to a localised fire, will not result in failure of the floor.A similar real fire test on a multistory reinforced concrete building demonstrated that the real structural behaviour in fire was significantly different to that expected using small displacement theory as for normal tempera- ture design (Bailey, 2002) with the performance being superior than that predicted by considering isolated member behaviour.3.4 Prescriptive Approach to DesignThe building regulations of most countries provide prescriptive requirements for the design of buildings for fire.These requirements are generally not subject to interpretation and compliance with them makes for simpler design approvalapproval––although not necessarily the most cost-effective designs.These provisions are often termed deemed-to-satisfy (DTS) provisions. Allcovered––the provision of emergency exits, aspects of designing buildings for fire safety are coveredspacings between buildings, occupant fire fighting measures, detection and alarms, measures for automatic fire suppression, air and smoke handling requirements and last, but not least, requirements for compartmentation and fire resistance levels for structural members. However, there is little evidence that the requirements have been developed from a systematic evaluation of fire safety. Rather it would appear that many of the requirements have been added one to anotherto deal with another fire incident or to incorporate a new form of technology. There does not appear to have been any real attempt to determine which provision have the most significant influence on fire safety and whether some of the former provisions could be modified.The FRL requirements specified in the DTS provisions are traditionally considered to result in member resistances that will only rarely experience failure in the event of a fire.This is why it is acceptable to use the above arbitrary point in time load combination for assessing members in fire. There have been attempts to evaluate the various deemed-to-satisfy provisions (particularly the fire- resistance requirements)from a fire-engineering perspective taking into account the possible variations in enclosure geometry, opening sizes and fire load (see FCRC, 1999).One of the outcomes of this evaluation was the recognition that deemed-to- satisfy provisions necessarily cover the broad range of buildings and thus must, on average, be quite onerous because of the magnitude of the above variations.It should be noted that the DTS provisions assume that compartmentation works and that fire is limited to a single compartment. This means that fire is normally only considered to exist at one level. Thus floors are assumed to be heated from below and columns only over one storey height.3.5 Performance-Based DesignAn approach that offers substantial benefits for individual buildings is the move towards performance-based regulations. This is permitted by regulations such as the BCA which state thata designer must demonstrate that the particular building will achieve the relevant performance requirements. The prescriptive provisions (i.e. the DTS provisions) are presumed to achieve these requirements. It is necessary to show that any building that does not conform to the DTS provisions will achieve the performance requirements.But what are the performance requirements? Most often the specified performance is simplya set of performance statements (such as with the Building Code of Australia)with no quantitative level given. Therefore, although these statements remind the designer of the key elements of design, they do not, in themselves, provide any measure against which to determine whether the design is adequately safe.Possible acceptance criteria are now considered.3.5.1 Acceptance CriteriaSome guidance as to the basis for acceptable designs is given in regulations such as the BCA. These and other possible bases are now considered in principle.(i)compare the levels of safety (with respect to achieving each of the design objectives) of the proposed alternative solution with those asso- ciated with a corresponding DTS solution for the building.This comparison may be done on either a qualitative or qualitative risk basis or perhaps a combination. In this case, the basis for comparison is an acceptable DTS solution. Such an approach requires a “holistic” approach to safety whereby all aspects relevant to safety, including the structure, are considered. This is, by far, the most common basis for acceptance.(ii)undertake a probabilistic risk assessment and show that the risk associated with the proposed design is less than that associated with common societal activities such as using pub lic transport. Undertaking a full probabilistic risk assessment can be very difficult for all but the simplest situations.Assuming that such an assessment is undertaken it will be necessary for the stakeholders to accept the nominated level of acceptable risk. Again, this requires a “holistic” approach to fire safety.(iii) a design is presented where it is demonstrated that all reasonable measures have been adopted to manage the risks and that any possible measures that have not been adopted will have negligible effect on the risk of not achieving the design objectives.(iv) as far as the building structure is concerned,benchmark the acceptable probability of failure in fire against that for normal temperature design. This is similar to the approach used when considering Building Situation 1 but only considers the building structure and not the effects of flame or smoke spread. It is not a holistic approach to fire safety.Finally, the questions of arson and terrorism must be considered. Deliberate acts of fire initiation range from relatively minor incidents to acts of mass destruction.Acts of arson are well within the accepted range of fire events experienced by build- ings(e.g. 8% of fire starts in offices are deemed "suspicious"). The simplest act is to use a small heat source to start a fire. The resulting fire will develop slowly in one location within the building and will most probably be controlled by the various fire- safety systems within the building. The outcome is likely to be the same even if an accelerant is used to assist fire spread.An important illustration of this occurred during the race riots in Los Angeles in 1992 (Hart 1992) when fires were started in many buildings often at multiple locations. In the case of buildings with sprinkler systems,the damage was limited and the fires significantly controlled.Although the intent was to destroy the buildings,the fire-safety systems were able to limit the resulting fires. Security measures are provided with systems such as sprinkler systems and include:- locking of valves- anti-tamper monitoring- location of valves in secure locationsFurthermore, access to significant buildings is often restricted by security measures.The very fact that the above steps have been taken demonstrates that acts of destruction within buildings are considered although most acts of arson do not involve any attempt to disable the fire-safety systems.At the one end of the spectrum is "simple" arson and at the other end, extremely rare acts where attempts are made to destroy the fire-safety systems along with substantial parts of thebuilding.This can be only achieved through massive impact or the use of explosives. The latter may be achieved through explosives being introduced into the building or from outside by missile attack.The former could result from missile attack or from the collision of a large aircraft. The greater the destructiveness of the act,the greater the means and knowledge required. Conversely, the more extreme the act, the less confidence there can be in designing against such an act. This is because the more extreme the event, the harder it is to predict precisely and the less understood will be its effects. The important point to recognise is that if sufficient means can be assembled, then it will always be possible to overcome a particular building design.Thus these acts are completely different to the other loadings to which a building is subjected such as wind,earthquake and gravity loading. This is because such acts of destruction are the work of intelligent beings and take into account the characteristics of the target.Should high-rise buildings be designed for given terrorist activities,then terrorists will simply use greater means to achieve the end result.For example, if buildings were designed to resist the impact effects from a certain size aircraft, then the use of a larger aircraft or more than one aircraft could still achieve destruction of the building. An appropriate strategy is therefore to minimise the likelihood of means of mass destruction getting into the hands of persons intent on such acts. This is not an engineering solution associated with the building structure.It should not be assumed that structural solutions are always the most appropriate, or indeed, possible.In the same way, aircrafts are not designed to survive a major fire or a crash landing but steps are taken to minimise the likelihood of either occurrence.The mobilization of large quantities of fire load (the normal combustibles on the floors) simultaneously on numerous levels throughout a building is well outside fire situations envisaged by current fire test standards and prescriptive regulations. Risk management measures to avoid such a possibility must be considered.4 CONCLUSIONSificantly from other “loads” such as wind, live load and earthquakes in significantlyFire differs signrespect of its origin and its effects.Due to the fact that fire originates from human activities or equipment installed within buildings, it is possible to directly influence the potential effects on the building by reducing the rate of fire starts and providing measures to directly limit fire severity.The design of buildings for fire safety is mostly achieved by following the prescriptive requirements of building codes such as the BCA. For situations that fall outside of the scope of such regulations, or where proposed designs are not in accordance with the prescriptive requirements, it is possible to undertake performance-based fire engineering designs.However,。

中英文文献以及翻译(化工类)

Foreign material：Chemical Industry1.Origins of the Chemical IndustryAlthough the use of chemicals dates back to the ancient civilizations, the evolution of what we know as the modern chemical industry started much more recently. It may be considered to have begun during the Industrial Revolution, about 1800, and developed to provide chemicals roe use by other industries. Examples are alkali for soapmaking, bleaching powder for cotton, and silica and sodium carbonate for glassmaking. It will be noted that these are all inorganic chemicals. The organic chemicals industry started in the 1860s with the exploitation of William Henry Perkin’s discovery if the first synthetic dyestuff—mauve. At the start of the twentieth century the emphasis on research on the applied aspects of chemistry in Germany had paid off handsomely, and by 1914 had resulted in the German chemical industry having 75% of the world market in chemicals. This was based on the discovery of new dyestuffs plus the development of both the contact process for sulphuric acid and the Haber process for ammonia. The later required a major technological breakthrough that of being able to carry out chemical reactions under conditions of very high pressure for the first time. The experience gained with this was to stand Germany in good stead, particularly with the rapidly increased demand for nitrogen-based compounds (ammonium salts for fertilizers and nitric acid for explosives manufacture) with the outbreak of world warⅠin 1914. This initiated profound changes which continued during the inter-war years (1918-1939).Since 1940 the chemical industry has grown at a remarkable rate, although this has slowed significantly in recent years. The lion’s share of this growth has been in the organic chemicals sector due to the development and growth of the petrochemicals area since 1950s. The explosives growth in petrochemicals in the 1960s and 1970s was largely due to the enormous increase in demand for synthetic polymers such as polyethylene, polypropylene, nylon, polyesters and epoxy resins.The chemical industry today is a very diverse sector of manufacturing industry, within which it plays a central role. It makes thousands of different chemicals whichthe general public only usually encounter as end or consumer products. These products are purchased because they have the required properties which make them suitable for some particular application, e.g. a non-stick coating for pans or a weedkiller. Thus chemicals are ultimately sold for the effects that they produce.2. Definition of the Chemical IndustryAt the turn of the century there would have been little difficulty in defining what constituted the chemical industry since only a very limited range of products was manufactured and these were clearly chemicals, e.g., alkali, sulphuric acid. At present, however, many intermediates to products produced, from raw materials like crude oil through (in some cases) many intermediates to products which may be used directly as consumer goods, or readily converted into them. The difficulty cones in deciding at which point in this sequence the particular operation ceases to be part of the chemical industry’s sphere of activities. To consider a specific example to illustrate this dilemma, emulsion paints may contain poly (vinyl chloride) / poly (vinyl acetate). Clearly, synthesis of vinyl chloride (or acetate) and its polymerization are chemical activities. However, if formulation and mixing of the paint, including the polymer, is carried out by a branch of the multinational chemical company which manufactured the ingredients, is this still part of the chemical industry of does it mow belong in the decorating industry?It is therefore apparent that, because of its diversity of operations and close links in many areas with other industries, there is no simple definition of the chemical industry. Instead each official body which collects and publishes statistics on manufacturing industry will have its definition as to which operations are classified as the chemical industry. It is important to bear this in mind when comparing statistical information which is derived from several sources.3. The Need for Chemical IndustryThe chemical industry is concerned with converting raw materials, such as crude oil, firstly into chemical intermediates and then into a tremendous variety of other chemicals. These are then used to produce consumer products, which make our livesmore comfortable or, in some cases such as pharmaceutical produces, help to maintain our well-being or even life itself. At each stage of these operations value is added to the produce and provided this added exceeds the raw material plus processing costs then a profit will be made on the operation. It is the aim of chemical industry to achieve this.It may seem strange in textbook this one to pose the question “do we need a chemical industry?” However trying to answer this question will provide(ⅰ) an indication of the range of the chemical industry’s activities, (ⅱ) its influence on our lives in everyday terms, and (ⅲ) how great is society’s need for a chemical industry. Our approach in answering the question will be to consider the industry’s co ntribution to meeting and satisfying our major needs. What are these? Clearly food (and drink) and health are paramount. Other which we shall consider in their turn are clothing and (briefly) shelter, leisure and transport.(1)Food. The chemical industry makes a major contribution to food production in at least three ways. Firstly, by making available large quantities of artificial fertilizers which are used to replace the elements (mainly nitrogen, phosphorus and potassium) which are removed as nutrients by the growing crops during modern intensive farming. Secondly, by manufacturing crop protection chemicals, i.e., pesticides, which markedly reduce the proportion of the crops consumed by pests. Thirdly, by producing veterinary products which protect livestock from disease or cure their infections.(2)Health. We are all aware of the major contribution which the pharmaceutical sector of the industry has made to help keep us all healthy, e.g. by curing bacterial infections with antibiotics, and even extending life itself, e.g. ß–blockers to lower blood pressure.(3)Clothing. The improvement in properties of modern synthetic fibers over the traditional clothing materials (e.g. cotton and wool) has been quite remarkable. Thus shirts, dresses and suits made from polyesters like Terylene and polyamides like Nylon are crease-resistant, machine-washable, and drip-dry or non-iron. They are also cheaper than natural materials.Parallel developments in the discovery of modern synthetic dyes and the technology to “bond” th em to the fiber has resulted in a tremendous increase in the variety of colors available to the fashion designer. Indeed they now span almost every color and hue of the visible spectrum. Indeed if a suitable shade is not available, structural modification of an existing dye to achieve this canreadily be carried out, provided there is a satisfactory market for the product.Other major advances in this sphere have been in color-fastness, i.e., resistance to the dye being washed out when the garment is cleaned.(4)Shelter, leisure and transport. In terms of shelter the contribution of modern synthetic polymers has been substantial. Plastics are tending to replace traditional building materials like wood because they are lighter, maintenance-free (i.e. they are resistant to weathering and do not need painting). Other polymers, e.g. urea-formaldehyde and polyurethanes, are important insulating materials f or reducing heat losses and hence reducing energy usage.Plastics and polymers have made a considerable impact on leisure activities with applications ranging from all-weather artificial surfaces for athletic tracks, football pitches and tennis courts to nylon strings for racquets and items like golf balls and footballs made entirely from synthetic materials.Like wise the chemical industry’s contribution to transport over the years has led to major improvements. Thus development of improved additives like anti-oxidants and viscosity index improves for engine oil has enabled routine servicing intervals to increase from 3000 to 6000 to 12000 miles. Research and development work has also resulted in improved lubricating oils and greases, and better brake fluids. Yet again the contribution of polymers and plastics has been very striking with the proportion of the total automobile derived from these materials—dashboard, steering wheel, seat padding and covering etc.—now exceeding 40%.So it is quite apparent even from a brief look at the chemical industry’s contribution to meeting our major needs that life in the world would be very different without the products of the industry. Indeed the level of a country’s development may be judged by the production level and sophistication of its chemical industry4. Research and Development (R&D) in Chemical IndustriesOne of the main reasons for the rapid growth of the chemical industry in the developed world has been its great commitment to, and investment in research and development (R&D). A typical figure is 5% of sales income, with this figure being almost doubled for the most research intensive sector, pharmaceuticals. It is important to emphasize that we are quoting percentages here not of profits but of sales income, i.e. the total money received, which has to pay for raw materials, overheads, staff salaries, etc. as well. In the past this tremendous investment has paid off well, leading to many useful and valuable products being introduced to the market. Examplesinclude synthetic polymers like nylons and polyesters, and drugs and pesticides. Although the number of new products introduced to the market has declined significantly in recent years, and in times of recession the research department is usually one of the first to suffer cutbacks, the commitment to R&D remains at a very high level.The chemical industry is a very high technology industry which takes full advantage of the latest advances in electronics and engineering. Computers are very widely used for all sorts of applications, from automatic control of chemical plants, to molecular modeling of structures of new compounds, to the control of analytical instruments in the laboratory.Individual manufacturing plants have capacities ranging from just a few tones per year in the fine chemicals area to the real giants in the fertilizer and petrochemical sectors which range up to 500,000 tonnes. The latter requires enormous capital investment, since a single plant of this size can now cost $520 million! This, coupled with the widespread use of automatic control equipment, helps to explain why the chemical industry is capital-rather than labor-intensive.The major chemical companies are truly multinational and operate their sales and marketing activities in most of the countries of the world, and they also have manufacturing units in a number of countries. This international outlook for operations, or globalization, is a growing trend within the chemical industry, with companies expanding their activities either by erecting manufacturing units in other countries or by taking over companies which are already operating there.化学工业1.化学工业的起源尽管化学品的使用可以追溯到古代文明时代，我们所谓的现代化学工业的发展却是非常近代（才开始的）。

交通安全外文翻译文献中英文

外文文献翻译(含：英文原文及中文译文)英文原文POSSIBILITIES AND LIMITA TIONS OF ACCIDENT ANALYSISS.OppeAbstraetAccident statistics, especially collected at a national level are particularly useful for the description, monitoring and prognosis of accident developments, the detection of positive and negative safety developments, the definition of safety targets and the (product) evaluation of long term and large scale safety measures. The application of accident analysis is strongly limited for problem analysis, prospective and retrospective safety analysis on newly developed traffic systems or safety measures, as well as for (process) evaluation of special short term and small scale safety measures. There is an urgent need for the analysis of accidents in real time, in combination with background behavioural research. Automatic incident detection, combined with video recording of accidents may soon result in financially acceptable research. This type of research may eventually lead to a better understanding of the concept of risk in traffic and to well-established theories.Keyword: Consequences; purposes; describe; Limitations; concerned; Accident Analysis; possibilities1. Introduction.This paper is primarily based on personal experience concerning traffic safety, safety research and the role of accidents analysis in this research. These experiences resulted in rather philosophical opinions as well as more practical viewpoints on research methodology and statistical analysis. A number of these findings are published already elsewhere.From this lack of direct observation of accidents, a number of methodological problems arise, leading to continuous discussions about the interpretation of findings that cannot be tested directly. For a fruitful discussion of these methodological problems it is very informative to look at a real accident on video. It then turns out that most of the relevant information used to explain the accident will be missing in the accident record. In-depth studies also cannot recollect all the data that is necessary in order to test hypotheses about the occurrence of the accident. For a particular car-car accident, that was recorded on video at an urban intersection in the Netherlands, between a car coming from a minor road, colliding with a car on the major road, the following questions could be asked: Why did the driver of the car coming from the minor road, suddenly accelerate after coming almost to a stop and hit the side of the car from the left at the main road? Why was the approaching car not noticed? Was it because the driver was preoccupied with the two cars coming from the right and the gap before them that offered him thepossibility to cross? Did he look left before, but was his view possibly blocked by the green van parked at the corner? Certainly the traffic situation was not complicated. At the moment of the accident there were no bicyclists or pedestrians present to distract his attention at the regularly overcrowded intersection. The parked green van disappeared within five minutes, the two other cars that may have been important left without a trace. It is hardly possible to observe traffic behavior under the most relevant condition of an accident occurring, because accidents are very rare events, given the large number of trips. Given the new video equipment and the recent developments in automatic incident and accident detection, it becomes more and more realistic to collect such data at not too high costs. Additional to this type of data that is most essential for a good understanding of the risk increasing factors in traffic, it also important to look at normal traffic behavior as a reference base. The question about the possibilities and limitations of accident analysis is not lightly answered. We cannot speak unambiguously about accident analysis. Accident analysis covers a whole range of activities, each originating from a different background and based on different sources of information: national data banks, additional information from other sources, especially collected accident data, behavioral background data etc. To answer the question about the possibilities and limitations, we first have to look at the cycle of activities in the area of traffic safety. Some ofthese activities are mainly concerned with the safety management of the traffic system; some others are primarily research activities.The following steps should be distinguished:- detection of new or remaining safety problems;- description of the problem and its main characteristics;- the analysis of the problem, its causes and suggestions for improvement;- selection and implementation of safety measures;- evaluation of measures taken.Although this cycle can be carried out by the same person or group of persons, the problem has a different (political/managerial or scientific) background at each stage. We will describe the phases in which accident analysis is used. It is important to make this distinction. Many fruitless discussions about the method of analysis result from ignoring this distinction. Politicians, or road managers are not primarily interested in individual accidents. From their perspective accidents are often treated equally, because the total outcome is much more important than the whole chain of events leading to each individual accident. Therefore, each accident counts as one and they add up all together to a final safety result.Researchers are much more interested in the chain of events leading to an individual accident. They want to get detailed information abouteach accident, to detect its causes and the relevant conditions. The politician wants only those details that direct his actions. At the highest level this is the decrease in the total number of accidents. The main source of information is the national database and its statistical treatment. For him, accident analysis is looking at (subgroups of) accident numbers and their statistical fluctuations. This is the main stream of accident analysis as applied in the area of traffic safety. Therefore, we will first describe these aspects of accidents.2. The nature of accidents and their statistical characteristics.The basic notion is that accidents, whatever there cause, appear according to a chance process. Two simple assumptions are usually made to describe this process for (traffic) accidents:- the probability of an accident to occur is independent from the occurrence of previous accidents;-the occurrence of accidents is homogeneous in time.If these two assumptions hold, then accidents are Poisson distributed. The first assumption does not meet much criticism. Accidents are rare events and therefore not easily influenced by previous accidents. In some cases where there is a direct causal chain (e.g. , when a number of cars run into each other) the series of accidents may be regarded as one complicated accident with many cars involved.The assumption does not apply to casualties. Casualties are often related to the same accident andtherefore the independency assumption does not hold. The second assumption seems less obvious at first sight. The occurrence of accidents through time or on different locations are not equally likely. However, the assumption need not hold over long time periods. It is a rather theoretical assumption in its nature. If it holds for short periods of time, then it also holds for long periods, because the sum of Poisson distributed variables, even if their Poisson rates are different, is also Poisson distributed. The Poisson rate for the sum of these periods is then equal to the sum of the Poisson rates for these parts.The assumption that really counts for a comparison of (composite) situations, is whether two outcomes from an aggregation of situations in time and/or space, have a comparable mix of basic situations. E.g. , the comparison of the number of accidents on one particular day of the year, as compared to another day (the next day, or the same day of the next week etc.). If the conditions are assumed to be the same (same duration, same mix of traffic and situations, same weather conditions etc.) then the resulting numbers of accidents are the outcomes of the same Poisson process. This assumption can be tested by estimating the rate parameter on the basis of the two observed values (the estimate being the average of the two values). Probability theory can be used to compute the likelihood of the equality assumption, given the two observations and their mean.This statistical procedure is rather powerful. The Poisson assumptionis investigated many times and turns out to be supported by a vast body of empirical evidence. It has been applied in numerous situations to find out whether differences in observed numbers of accidents suggest real differences in safety. The main purpose of this procedure is to detect differences in safety. This may be a difference over time, or between different places or between different conditions. Such differences may guide the process of improvement. Because the main concern is to reduce the number of accidents, such an analysis may lead to the most promising areas for treatment. A necessary condition for the application of such a test is, that the numbers of accidents to be compared are large enough to show existing differences. In many local cases an application is not possible. Accident black-spot analysis is often hindered by this limitation, e.g., if such a test is applied to find out whether the number of accidents at a particular location is higher than average. The procedure described can also be used if the accidents are classified according to a number of characteristics to find promising safety targets. Not only with aggregation, but also with disaggregation the Poisson assumption holds, and the accident numbers can be tested against each other on the basis of the Poisson assumptions. Such a test is rather cumbersome, because for each particular case, i.e. for each different Poisson parameter, the probabilities for all possible outcomes must be computed to apply the test. In practice, this is not necessary when the numbers are large. Then the Poissondistribution can be approximated by a Normal distribution, with mean and variance equal to the Poisson parameter. Once the mean value and the variance of a Normal distribution are given, all tests can be rephrased in terms of the standard Normal distribution with zero mean and variance one. No computations are necessary any more, but test statistics can be drawn from tables.3. The use of accident statistics for traffic safety policy.The testing procedure described has its merits for those types of analysis that are based on the assumptions mentioned. The best example of such an application is the monitoring of safety for a country or region over a year, using the total number of accidents (eventually of a particular type, such as fatal accidents), in order to compare this number with the outcome of the year before. If sequences of accidents are given over several years, then trends in the developments can be detected and accident numbers predicted for following years. Once such a trend is established, then the value for the next year or years can be predicted, together with its error bounds. Deviations from a given trend can also be tested afterwards, and new actions planned. The most famous one is carried out by Smeed 1949. We will discuss this type of accident analysis in more detail later.(1). The application of the Chi-square test for interaction is generalised to higher order classifications. Foldvary and Lane (1974), inmeasuring the effect of compulsory wearing of seat belts, were among the first who applied the partitioning of the total Chi-square in values for the higher order interactions of four-way tables.(2). Tests are not restricted to overall effects, but Chi-square values can be decomposed regarding sub-hypotheses within the model. Also in the two-way table, the total Chisquare can be decomposed into interaction effects of part tables. The advantage of 1. and 2. over previous situations is, that large numbers of Chi-square tests on many interrelated (sub)tables and corresponding Chi-squares were replaced by one analysis with an exact portioning of one Chi-square.(3). More attention is put to parameter estimation. E.g., the partitioning of the Chi-square made it possible to test for linear or quadratic restraints on the row-parameters or for discontinuities in trends.(4). The unit of analysis is generalised from counts to weighted counts. This is especially advantageous for road safety analyses, where corrections for period of time, number of road users, number of locations or number of vehicle kilometres is often necessary. The last option is not found in many statistical packages. Andersen 1977 gives an example for road safety analysis in a two-way table. A computer programme WPM, developed for this type of analysis of multi-way tables, is available at SWOV (see: De Leeuw and Oppe 1976). The accident analysis at this level is not explanatory. It tries to detect safety problems that need specialattention. The basic information needed consists of accident numbers, to describe the total amount of unsafety, and exposure data to calculate risks and to find situations or (groups of) road users with a high level of risk. 4. Accident analysis for research purposes.Traffic safety research is concerned with the occurrence of accidents and their consequences. Therefore, one might say that the object of research is the accident. The researcher’s interest however is less focused at this final outcome itself, but much more at the process that results (or does not result) in accidents. Therefore, it is better to regard the critical event in traffic as his object of study. One of the major problems in the study of the traffic process that results in accidents is, that the actual occurrence is hardly ever observed by the researcher.Investigating a traffic accident, he will try to reconstruct the event from indirect sources such as the information given by the road users involved, or by eye-witnesses, about the circumstances, the characteristics of the vehicles, the road and the drivers. As such this is not unique in science, there are more examples of an indirect study of the object of research. However, a second difficulty is, that the object of research cannot be evoked. Systematic research by means of controlled experiments is only possible for aspects of the problem, not for the problem itself. The combination of indirect observation and lack of systematic control make it very difficult for the investigator to detectwhich factors, under what circumstances cause an accident. Although the researcher is primarily interested in the process leading to accidents, he has almost exclusively information about the consequences, the product of it, the accident. Furthermore, the context of accidents is complicated. Generally speaking, the following aspects can be distinguished: - Given the state of the traffic system, traffic volume and composition, the manoeuvres of the road users, their speeds, the weather conditions, the condition of the road, the vehicles, the road users and their interactions, accidents can or cannot be prevented.- Given an accident, also depending on a large number of factors, such as the speed and mass of vehicles, the collision angle, the protection of road users and their vulnerability, the location of impact etc., injuries are more or less severe or the material damage is more or less substantial. Although these aspects cannot be studied independently, from a theoretical point of view it has advantages to distinguish the number of situations in traffic that are potentially dangerous, from the probability of having an accident given such a potentially dangerous situation and also from the resulting outcome, given a particular accident.This conceptual framework is the general basis for the formulation of risk regarding the decisions of individual road users as well as the decisions of controllers at higher levels. In the mathematical formulation of risk we need an explicit description of our probability space, consistingof the elementary events (the situations) that may result in accidents, the probability for each type of event to end up in an accident, and finally the particular outcome, the loss, given that type of accident.A different approach is to look at combinations of accident characteristics, to find critical factors. This type of analysis may be carried out at the total group of accidents or at subgroups. The accident itself may be the unit of research, but also a road, a road location, a road design (e.g. a roundabout) etc.中文译文交通事故分析的可能性和局限性S.Oppe摘要交通事故的统计数字, 尤其国家一级的数据对监控和预测事故的发展, 积极或消极检测事故的发展, 以及对定义安全目标和评估工业安全特别有益。

道路与桥梁工程中英文对照外文翻译文献

中英文对照外文翻译(文档含英文原文和中文翻译)Bridge research in EuropeA brief outline is given of the development of the European Union, together withthe research platform in Europe. The special case of post-tensioned bridges in the UK is discussed. In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio: relating to the identification of voids in post-tensioned concrete bridges using digital impulse radar.IntroductionThe challenge in any research arena is to harness the findings of different research groups to identify a coherent mass of data, which enables research and practice to be better focused. A particular challenge exists with respect to Europe where language barriers are inevitably very significant. The European Community was formed in the 1960s based upon a political will within continental Europe to avoid the European civil wars, which developed into World War 2 from 1939 to 1945. The strong political motivation formed the original community of which Britain was not a member. Many of the continental countries saw Britain’s interest as being purelyeconomic. The 1970s saw Britain joining what was then the European Economic Community (EEC) and the 1990s has seen the widening of the community to a European Union, EU, with certain political goals together with the objective of a common European currency.Notwithstanding these financial and political developments, civil engineering and bridge engineering in particular have found great difficulty in forming any kind of common thread. Indeed the educational systems for University training are quite different between Britain and the European continental countries. The formation of the EU funding schemes —e.g. Socrates, Brite Euram and other programs have helped significantly. The Socrates scheme is based upon the exchange of students between Universities in different member states. The Brite Euram scheme has involved technical research grants given to consortia of academics and industrial partners within a number of the states—— a Brite Euram bid would normally be led by partners within a number of the statesan industrialist.In terms of dissemination of knowledge, two quite different strands appear to have emerged. The UK and the USA have concentrated primarily upon disseminating basic research in refereed journal publications: ASCE, ICE and other journals. Whereas the continental Europeans have frequently disseminated basic research at conferences where the circulation of the proceedings is restricted.Additionally, language barriers have proved to be very difficult to break down. In countries where English is a strong second language there has been enthusiastic participation in international conferences based within continental Europe —e.g. Germany, Italy, Belgium, The Netherlands and Switzerland. However, countries where English is not a strong second language have been hesitant participants }—e.g. France.European researchExamples of research relating to bridges in Europe can be divided into three types of structure:Masonry arch bridgesBritain has the largest stock of masonry arch bridges. In certain regions of the UK up to 60% of the road bridges are historic stone masonry arch bridges originally constructed for horse drawn traffic. This is less common in other parts of Europe as many of these bridges were destroyed during World War 2.Concrete bridgesA large stock of concrete bridges was constructed during the 1950s, 1960s and 1970s. At the time, these structures were seen as maintenance free. Europe also has a large number of post-tensioned concrete bridges with steel tendon ducts preventing radar inspection. This is a particular problem in France and the UK.Steel bridgesSteel bridges went out of fashion in the UK due to their need for maintenance as perceived in the 1960s and 1970s. However, they have been used for long span and rail bridges, and they are now returning to fashion for motorway widening schemes in the UK.Research activity in EuropeIt gives an indication certain areas of expertise and work being undertaken in Europe, but is by no means exhaustive.In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio. The example relates to the identification of voids in post-tensioned concrete bridges, using digital impulse radar.Post-tensioned concrete rail bridge analysisOve Arup and Partners carried out an inspection and assessment of the superstructure of a 160 m long post-tensioned, segmental railway bridge in Manchester to determine its load-carrying capacity prior to a transfer of ownership, for use in the Metrolink light rail system..Particular attention was paid to the integrity of its post-tensioned steel elements.Physical inspection, non-destructive radar testing and other exploratory methods were used to investigate for possible weaknesses in the bridge.Since the sudden collapse of Ynys-y-Gwas Bridge in Wales, UK in 1985, there has been concern about the long-term integrity of segmental, post-tensioned concrete bridges which may b e prone to ‘brittle’ failure without warning. The corrosion protection of the post-tensioned steel cables, where they pass through joints between the segments, has been identified as a major factor affecting the long-term durability and consequent strength of this type of bridge. The identification of voids in grouted tendon ducts at vulnerable positions is recognized as an important step in the detection of such corrosion.Description of bridgeGeneral arrangementBesses o’ th’ Barn Bridge is a 160 m long, three span, segmental, post-tensionedconcrete railway bridge built in 1969. The main span of 90 m crosses over both the M62 motorway and A665 Bury to Prestwick Road. Minimum headroom is 5.18 m from the A665 and the M62 is cleared by approx 12.5 m.The superstructure consists of a central hollow trapezoidal concrete box section 6.7 m high and 4 m wide. The majority of the south and central spans are constructed using 1.27 m long pre-cast concrete trapezoidal box units, post-tensioned together. This box section supports the in site concrete transverse cantilever slabs at bottom flange level, which carry the rail tracks and ballast.The center and south span sections are of post-tensioned construction. These post-tensioned sections have five types of pre-stressing:1. Longitudinal tendons in grouted ducts within the top and bottom flanges.2. Longitudinal internal draped tendons located alongside the webs. These are deflected at internal diaphragm positions and are encased in in site concrete.3. Longitudinal macalloy bars in the transverse cantilever slabs in the central span .4. Vertical macalloy bars in the 229 mm wide webs to enhance shear capacity.5. Transverse macalloy bars through the bottom flange to support the transverse cantilever slabs.Segmental constructionThe pre-cast segmental system of construction used for the south and center span sections was an alternative method proposed by the contractor. Current thinkingire suggests that such a form of construction can lead to ‘brittle’ failure of the ententire structure without warning due to corrosion of tendons across a construction joint，The original design concept had been for in site concrete construction.Inspection and assessmentInspectionInspection work was undertaken in a number of phases and was linked with the testing required for the structure. The initial inspections recorded a number of visible problems including:Defective waterproofing on the exposed surface of the top flange.Water trapped in the internal space of the hollow box with depths up to 300 mm.Various drainage problems at joints and abutments.Longitudinal cracking of the exposed soffit of the central span.Longitudinal cracking on sides of the top flange of the pre-stressed sections.Widespread sapling on some in site concrete surfaces with exposed rusting reinforcement.AssessmentThe subject of an earlier paper, the objectives of the assessment were:Estimate the present load-carrying capacity.Identify any structural deficiencies in the original design.Determine reasons for existing problems identified by the inspection.Conclusion to the inspection and assessmentFollowing the inspection and the analytical assessment one major element of doubt still existed. This concerned the condition of the embedded pre-stressing wires, strands, cables or bars. For the purpose of structural analysis these elements、had been assumed to be sound. However, due to the very high forces involved,、a risk to the structure, caused by corrosion to these primary elements, was identified.The initial recommendations which completed the first phase of the assessment were:1. Carry out detailed material testing to determine the condition of hidden structural elements, in particularthe grouted post-tensioned steel cables.2. Conduct concrete durability tests.3. Undertake repairs to defective waterproofing and surface defects in concrete.Testing proceduresNon-destructi v e radar testingDuring the first phase investigation at a joint between pre-cast deck segments the observation of a void in a post-tensioned cable duct gave rise to serious concern about corrosion and the integrity of the pre-stress. However, the extent of this problem was extremely difficult to determine. The bridge contains 93 joints with an average of 24 cables passing through each joint, i.e. there were approx. 2200 positions where investigations could be carried out. A typical section through such a joint is that the 24 draped tendons within the spine did not give rise to concern because these were protected by in site concrete poured without joints after the cables had been stressed.As it was clearly impractical to consider physically exposing all tendon/joint intersections, radar was used to investigate a large numbers of tendons and hence locate duct voids within a modest timescale. It was fortunate that the corrugated steel ducts around the tendons were discontinuous through the joints which allowed theradar to detect the tendons and voids. The problem, however, was still highly complex due to the high density of other steel elements which could interfere with the radar signals and the fact that the area of interest was at most 102 mm wide and embedded between 150 mm and 800 mm deep in thick concrete slabs.Trial radar investigations.Three companies were invited to visit the bridge and conduct a trial investigation. One company decided not to proceed. The remaining two were given 2 weeks to mobilize, test and report. Their results were then compared with physical explorations.To make the comparisons, observation holes were drilled vertically downwards into the ducts at a selection of 10 locations which included several where voids were predicted and several where the ducts were predicted to be fully grouted. A 25-mm diameter hole was required in order to facilitate use of the chosen horoscope. The results from the University of Edinburgh yielded an accuracy of around 60%.Main radar sur v ey, horoscope verification of v oids.Having completed a radar survey of the total structure, a baroscopic was then used to investigate all predicted voids and in more than 60% of cases this gave a clear confirmation of the radar findings. In several other cases some evidence of honeycombing in the in site stitch concrete above the duct was found.When viewing voids through the baroscopic, however, it proved impossible to determine their actual size or how far they extended along the tendon ducts although they only appeared to occupy less than the top 25% of the duct diameter. Most of these voids, in fact, were smaller than the diameter of the flexible baroscopic being used (approximately 9 mm) and were seen between the horizontal top surface of the grout and the curved upper limit of the duct. In a very few cases the tops of the pre-stressing strands were visible above the grout but no sign of any trapped water was seen. It was not possible, using the baroscopic, to see whether those cables were corroded.Digital radar testingThe test method involved exciting the joints using radio frequency radar antenna: 1 GHz, 900 MHz and 500 MHz. The highest frequency gives the highest resolution but has shallow depth penetration in the concrete. The lowest frequency gives the greatest depth penetration but yields lower resolution.The data collected on the radar sweeps were recorded on a GSSI SIR System 10.This system involves radar pulsing and recording. The data from the antenna is transformed from an analogue signal to a digital signal using a 16-bit analogue digital converter giving a very high resolution for subsequent data processing. The data is displayed on site on a high-resolution color monitor. Following visual inspection it isthen stored digitally on a 2.3-gigabyte tape for subsequent analysis and signal processing. The tape first of all records a ‘header’ noting the digital radar settings together with the trace number prior to recording the actual data. When the data is played back, one is able to clearly identify all the relevant settings —making for accurate and reliable data reproduction.At particular locations along the traces, the trace was marked using a marker switch on the recording unit or the antenna.All the digital records were subsequently downloaded at the University’s NDT laboratory on to a micro-computer.（The raw data prior to processing consumed 35 megabytes of digital data.） Post-processing was undertaken using sophisticated signal processing software. Techniques available for the analysis include changing the color transform and changing the scales from linear to a skewed distribution in order to highlight、突出certain features. Also, the color transforms could be changed to highlight phase changes. In addition to these color transform facilities, sophisticated horizontal and vertical filtering procedures are available. Using a large screen monitor it is possible to display in split screens the raw data and the transformed processed data. Thus one is able to get an accurate indication of the processing which has taken place. The computer screen displays the time domain calibrations of the reflected signals on the vertical axis.A further facility of the software was the ability to display the individual radar pulses as time domain wiggle plots. This was a particularly valuable feature when looking at individual records in the vicinity of the tendons.Interpretation of findingsA full analysis of findings is given elsewhere, Essentially the digitized radar plots were transformed to color line scans and where double phase shifts were identified in the joints, then voiding was diagnosed.Conclusions1. An outline of the bridge research platform in Europe is given.2. The use of impulse radar has contributed considerably to the level of confidence in the assessment of the Besses o’ th’ Barn Rail Bridge.3. The radar investigations revealed extensive voiding within the post-tensioned cable ducts. However, no sign of corrosion on the stressing wires had been foundexcept for the very first investigation.欧洲桥梁研究欧洲联盟共同的研究平台诞生于欧洲联盟。

英文文献小短文(原文加汉语翻译)

A fern that hyperaccumulates arsenic(这是题目，百度一下就能找到原文好，原文还有表格，我没有翻译)A hardy, versatile, fast-growing plant helps to remove arsenic from contaminated soilsContamination of soils with arsenic,which is both toxic and carcinogenic, is widespread1. We have discovered that the fern Pteris vittata (brake fern) is extremely efficient in extracting arsenic from soils and translocating it into its above-ground biomass. This plant —which, to our knowledge, is the first known arsenic hyperaccumulator as well as the first fern found to function as a hyperaccumulator— has many attributes that recommend it for use in the remediation of arsenic-contaminated soils.We found brake fern growing on a site in Central Florida contaminated with chromated copper arsenate (Fig. 1a). We analysed the fronds of plants growing at the site for total arsenic by graphite furnace atomic absorption spectroscopy. Of 14 plant species studied, only brake fern contained large amounts of arsenic (As;3,280–4,980 We collected additional samples of the plant and soil from the contaminated site –1,603 As) and from an uncontaminated site –As). Brake fern extracted arsenic efficiently from these soils into its fronds: plantsgrowing in the contaminated site contained 1,442–7,526 Arsenic and those from the uncontaminated site contained –These values are much higher than those typical for plants growing in normal soil, which contain less than of arsenic3.As well as being tolerant of soils containing as much as 1,500 arsenic, brake fern can take up large amounts of arsenic into its fronds in a short time (Table 1). Arsenic concentration in fern fronds growing in soil spiked with 1,500 Arsenic increased from to 15,861 in two weeks. Furthermore, in the same period, ferns growing in soil containing just 6 arsenic accumulated 755 Of arsenic in their fronds, a 126-fold enrichment. Arsenic concentrations in brake fernroots were less than 303 whereas those in the fronds reached 7,234 of 100 Arsenic significantly stimulated fern growth, resulting in a 40% increase in biomass compared with the control (data not shown).After 20 weeks of growth, the plant was extracted using a solution of 1:1 methanol:water to speciate arsenic with high-performance liquid chromatography–inductively coupled plasma mass spectrometry. Almost all arsenic was present as relatively toxic inorganic forms, with little detectable organoarsenic species4. The concentration of As(III) was greater in the fronds (47–80%) than in the roots %), indicating that As(V)was converted to As(III) during translocation from roots to fronds.As well as removing arsenic from soils containing different concentrations of arsenic (Table 1), brake fern also removed arsenic from soils containing different arsenic species (Fig. 1c). Again, up to 93% of the arsenic was concentrated in the fronds. Although both FeAsO4 and AlAsO4 are relatively insoluble in soils1, brake fern hyperaccumulated arsenic derived from these compounds into its fronds (136–315 levels 3–6 times greater than soil arsenic.Brake fern is mesophytic and is widely cultivated and naturalized in many areas with a mild climate. In the United States, it grows in the southeast and in southern California5. The fern is versatile and hardy, and prefers sunny (unusual for a fern) and alkaline environments (where arsenic is more available). It has considerable biomass, and is fast growing, easy to propagate,and perennial.We believe this is the first report of significant arsenic hyperaccumulation by an unmanipulated plant. Brake fern has great potential to remediate arsenic-contaminated soils cheaply and could also aid studies of arsenic uptake, translocation, speciation, distribution anddetoxification in plants.*Soil and Water Science Department, University ofFlorida, Gainesville, Florida 32611-0290, USAe-mail†Cooperative Extension Service, University ofGeorgia, Terrell County, PO Box 271, Dawson,Georgia 31742, USA‡Department of Chemistry & SoutheastEnvironmental Research Center, FloridaInternational University, Miami, Florida 33199,1. Nriagu, J. O. (ed.) Arsenic in the Environment Part 1: Cycling and Characterization (Wiley, New York, 1994).2. Brooks, R. R. (ed.) Plants that Hyperaccumulate Heavy Metals (Cambridge Univ. Press, 1998).3. Kabata-Pendias, A. & Pendias, H. in Trace Elements in Soils and Plants 203–209 (CRC, Boca Raton, 1991).4. Koch, I., Wang, L., Ollson, C. A., Cullen, W. R. & Reimer, K. J. Envir. Sci. Technol. 34, 22–26 (2000).5. Jones, D. L. Encyclopaedia of Ferns (Lothian, Melbourne, 1987).积累砷的蕨类植物耐寒，多功能，生长快速的植物，有助于从污染土壤去除砷有毒和致癌的土壤砷污染是非常广泛的。

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REVISTA BOLIVIANA DE QUÍMICA VOLUMEN 25, No.1 - 2008DETERMINATION OF TOTAL PHENOLIC COMPOUNDSCONTENT AND THE ANTIOXIDANT CAPACITY OF ANDEAN TUBERS AND ROOTS (OCA, ULLUCO AND ARRACACHA)Trinidad G. Salluca abc, J. Mauricio Peñarrieta abc, J. Antonio Alvarado a* and Björn Bergenståhl ca Instituto de Investigaciones Químicas, Universidad Mayor de San Andrés, La Paz-Bolivia,b Biomedical Nutrition, LundUniversity, Lund-Sweden, c Food Technology, Lund University, Lund-SwedenKey Words: Andean tubers, oca, ulluco, roots of arracacha, Total Antioxidant Capacity, ABTS, FRAP,Total Phenolic Compounds.ABSTRACTFour species of Andean tubers, isaño (Tropaeolum tuberosum), oca (Oxalis tuberosa), ulluco (Ullucus tuberosus) and roots of arracacha (Arracacia xanthorrhiza), were studied for the quantification of the Total Antioxidant Capacity (TAC) and determination of Total Phenolic Compounds (TPH). The total antioxidant capacity was measured using ABTS and FRAP methods, and the total phenolics compounds were measured using the Folin & Ciocalteu reagent. The antioxidant capacity found in the tubers and root studied ranged from 0.35 to 11.8 μmol trolox equiv/g dry sample, and phenolics ranged from 0.002 to 0.02 μmol gallic acid equiv./g dry sample. In genera l black isaño tubers showed the highest values of antioxidant capacity and phenolic compounds compared with the other tubers.INTRODUCTIONThe interest in natural antioxidants has increased considerably in recent years because many antioxidants exhibit beneficial biological effects, including antibacterial, antiviral, antiallergic, antithrombotic and because they arelinked to lower incidence of cardiovascular disease and certain types of cancer disease [1]. The Andean habitantshave been using tubers and roots such as isaño, oca, ulluco and arracacha for their medicinal and nutritionalproperties since remote times. The diversity of tubers growing in the Andean region at altitudes between 2000 and4200 m above sea level shows a large variability in size, color, form, primary nutrient constituents and secondary metabolites [2, 3, 4]. Bolivia is well known for its ample diversity of genetic recourses of potential utility for the humanity. The traditions and the diversity of cultivation constitutes an important source of knowledge that must be systematized and utilized by means of different actions. Andean tubers have a big importance for the food supply and economy of the people living in the Andean region who eat isaño, oca, ulluco and arracacha both fresh and dry. The unfavorable climate at high altitudes only permits a limited number of cultivars. They are also used in folk medicine [5]. These mostly unproven medicinal properties could in part be attributed to the antioxidants present in these tubers. The objective of this study was to provide new data regarding Andean tubers and roots from Bolivia as asource of antioxidant compoundsRESULTS AND DISCUSSIONTotal Antioxidant Capacity of Andean tubersThe TAC values measured in the polar and non-polar extracts from seven samples by the ABTS and FRAP methodsare shown in Table 1and 2. The highest TAC value was observed in black isaño in the methanol extract.1esTScuthAPds meIntermediatte values were found in yellow isaño, yellow oca, arracach and dappled ulluco, and lowwer TAC value. were demonstrateed in pink oca and pink ulluuco. For black isaño higher TAC values were obtained in the polar fraactions (methanol and ethyl acetaate) than in the non-polar fractions (dichloroomethane and petroleum etheer) by the ABT and FRAP methhods. The TAC values of the calibration urves showed good reproducibbility (Figure 1,2) by both meethods. Data from FRAP displayyed a linear corrrelation with TPH data for the 28 extracts (r =0.96; Figuure 3). Similar linear correlations have also beeen observed in previous studie [6]. The TAC values obtainned for Andean tuber samples usingthe FRAP method were in most, but not in all cases, higgher than those obtained with the ABTS methhod. In black isaaño the highest valuues was found by the ABTS method in the methanol extract as well as in he total value of TAC.Figure 1: Calibration currve obtained by FRA method on diffeferent days for the measure of TAC xpressed as Trolox Equivalents/L (TE)Figure 2: Calibration currve obtained by ABBTS method on diffferent days for the measure of TAC xpressed as trolox equivalent s/L (TE)Figure 3:: Relation betweenn TAC-FRAP and TPH measuremennts in the 28 extraccts of 7 andean tubers.FRAP and ABTS method have been ussed for analysis of TAC in diffferent kinds of foods and som data on tubeers and roots are avvailable [7, 8]. Previous TAC values on tubeers were approxx. 0.27 – 3.03 µmol/g fresh ssample and 0.9 – 14.7 µmol/g dry sample using ABTS and 0.32 – 1.57 µmol/g fw and 1.0 - 7.6 µmol/g dw by FRAP.Total Phennolic Compounnds of Andeann tubers 2The content of Total Phenolic Compounds of the seven samples and twenty-eight extracts measured using the Folin& Ciocalteau method is shown in Table 3. The highest value was obtained in black isaño in both the methanol andethyl acetate extracts. In the present study the range of TPH determined in tuber pulp was 0.002-0.02 µmol GAE/gdm expressed as the sum of the polar and non polar fractions. The values of Total Phenolic Compounds of theextracts showed a good linear correlation (Figure 3) between TAC values obtained by FRAP (r =0.96) and by ABTS(r =0.78) methods.EXPERIMENTAL SECTIONChemicalsTrolox (6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid, 97%.), TPTZ (2,4,6-tripyridyl-s-triazine), ABTS (2,2’-azinobis-3-ethyl benzotiazoline-6-sulphonic acid, 98%), potassium persulfate, sodium acetate, Folin-Ciocalteau reagent, gallic acid (98%) and sodium carbonate were purchased from Sigma-Aldrich (St. Louis, USA).The solvents used were: methanol, ethanol, dichloromethane, ethylacetate and petroleum ether.Plant materialSeven samples of andean tubers were purchased in the markets of La Paz, Bolivia in June 2006. The selected plants were ulluco (Ullucus tuberosus), arracacha (Arracacia xanthorrhiza), oca (Oxalis tuberosa) and isaño (Tropaeolum tuberosum). The seven varieties of samples were: two samples of oca (pink and yellow), two samples of Isaño (yellow with blach eyes and black), two samples of Ulluco (pink and dappled) and a sample of Arracha (yellow).Sample preparationThe collected tubers and root were washed and peeled and 800 g of fresh sample was dried at 30°C during 24 hours. The dry samples (only dry pulp) were ground and sequentially soaked with petroleum ether, dichloromethane, ethyl acetate and methanol during 24 hrs for each solvent. TAC and TPH were measured in the seventy-eight concentrated extracts.Measurement of TACTAC was assessed by using the ABTS [2,2’-azinobis (3-ethylbenzothiazoline-6-sulphonic acid)] method describedby Re et al. [9] and a modification of the FRAP (Ferric Reducing Antioxidant Power) method described by Benzie & Strain [10]. Both are spectrophotometric methods and the absorbance readings were performed on a double beamUV-Visible spectrophotometer Perkin Elmer model lambda 25 at 25°C. As a standard compound Trolox (6-hydroxy- 2,5,7,8–tetramethyl-chroman-2-carboxylic acid) was used, The stock solution contained 5 mmol/L of Trolox in ethanol, and was stored at 4°C.ABTS method. The ABTS method is based on the oxidation of ABTS to the green ABTS·+ radical cation after the addition of potassium persulphate (2.42 mmol/L) [11] for 12-16 hours at room temperature in the dark. On the day of analysis the ABTS·+ solution was diluted with acetate buffer pH 5.0 to an absorbance of 0.70 (±0.02) at 734 nm.After the addition of 1.0 of ABTS·+ solution to 100 µl of sample the mixture was stirred for 30 s and the absorbanceat 734 nm and 25°C was recorded for 6 min. The decrease in absorbance caused by the addition of sample was compared with that of a standard curve by use of Trolox (20-200 µmol/L).FRAP (ferric reducing/antioxidant power) method. The FRAP method was used for the determination of total antioxidant capacity, based on the reduction of yellow Fe3+-TPTZ complex to the blue Fe2+ -TPTZ complex by electron donating substance under acidic co ndition. The FRAP reagent (900 μl) containing TPTZ, FeCl3, and acetate buffer, was mixed with 90 μl of distilled water and 30 μl of the test sample or the blank (solvents used for extraction). Maximum absorbance values at 593 nm were recorded for 10 min at 25°C. The final absorbance was compared with the standard curve (100 –1000 μmol/L). The data were expressed as μmol trolox equivalents pergram of dry matter.Measurement of total phenolic compoundsThe phenolic compounds were determined using the Folin-Ciocalteu method, based on the reduction ofphosphor-wolframate-phosphomolybdate complex by phenolics to a blue reaction product [12, 13, 14]. TheFolin-Ciocalteu reagent, diluted 10 times (2.5 ml) was mixed with 2 ml of saturated sodium carbonate (75 g/L) and350 μl of sample (supernatant) and homogenized for 10 s and heated for 30 min at 45°C. The absorbance was measured at 765 nm after cooling at room temperature. The data were calculated by comparison between a standard curve (212-1062 μmol gallic acid /L) and the absorbance of each sample. The data were expressed as μmol gallic acid equivalents per gram of dry matter.Statistical Analysis.Results were expressed as mean values (standard deviation) of six replicates measured over three days of one extract. Linear correlation coefficient was calculated.ACKNOWLEDGEMENTSThe study was supported by the Swedish International Development Agency (SIDA/SAREC) in a collaborative project between Universidad Mayor de San Andrés (Bolivia) and Lund University (Sweden).REFERENCES[1] Nilsson J, Pillai D, Önning G, Persson C, Nilsson Å, Åkesson B. “Co mparison of the ABTS and FRAP methods to assess the total antioxidant capacity in extracts of fruit and vegetables.” Molecular Nutrition and Food Research, 2005, 49: 239-246[2] León, J. Botánica de los cultivos tropicales. Herbario Nacional de Bolivia, Bolivia 1997.[3] De Lucca, M. D.; Zalles, A. J. Flora Medicinal Boliviana Diccionario Enciclopédico. Los Amigos del Libro, Cochabamba - Bolivia 1992.[4] Vimos, C. N.; Nieto C.; Rivera M. El Melloco Características, técnicas de cultivo y potencial en Ecuador”. 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Flour: Comparative Spectrophotometric Study among Extraction Methods of Free and Bound Phen olic Compounds”. Journal of the Science Food Chemistry 2004, 84 5195- 5200.[14] Singleton, V.L.; Rossi, J. A. Jr. “Colorimetry of total phenolics with phosphomolybdic-phosphotungtic acid reagent”. American journal of Enology and Viticulture, 1965, 16, 144-158.4总酚类化合物含量测定以及南美洲根筋类植物的抗氧化能力Trinidad G. Salluca abc, J. Mauricio Peñarrieta abc, J. Antonio Alvarado a* and Björn Bergenståhl cInstituto de Investigaciones Químicas, Universidad Mayor de San Andrés, La Paz-Bolivia, b Biomedical Nutrition, LundUniversity, Lund-Sweden, c Food Technology,Lund University, Lund-Sweden关键词：南美洲根筋类植物，大洋洲，胡萝卜根部，总抗氧化能力，2，2′-连氮-二(3-乙基苯并噻唑啉-6-磺酸)，三价铁降低抗氧化(剂)能力，总酚类化合物含量。