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译文题目： 现代交通运输对环境和历史的影响 Environmental Impact and History of Modern TransportationThe development of internal combustion (IC) engine vehicles, and especially automobiles, is one of the greatest achievements of modern technology. Automobile shave made great contributions to the growth of modern society by satisfying many of the needs for mobility in everyday life. The rapid development of the automotive industry, unlike that of any other industry, has prompted the progress of human beings from a primitive security to a highly developed industrial one. The automobile industry and the other industries that serve it constitute the backbone of the worlds economy and employ the greatest share of the working population.However, the large number of automobiles in use around the world has caused and continues to cause serious problems for environment and human life. Air pollution, global warming, and the rapid depletion of the Earths petroleum resources are now problems of paramount concern.In recent decades, the research and development activities related to transportation have emphasized the development of high-efficiency, clean, and safe transportation. Electric vehicles (EVs), hybrid electric vehicles (HEVs),and fuel cell vehicles have been typically proposed to replace conventional vehicles in the near future.This chapter reviews the problems of air pollution, gas emissions causing global warming, and petroleum resource depletion. It also gives a brief review of the history of EVs, HEVs, and fuel cell technology.1.1 Air PollutionAt present, all vehicles rely on the combustion of hydrocarbon (HC) fuels to derive the energy necessary for their propulsion. Combustion is a reaction between the fuel and the air that releases heat and combustion products.The heat is converted to mechanical power by an engine and the combustion products are released to the atmosphere.An HC is a chemical compound with molecules made up of carbon and hydrogen atoms. Ideally, the combustion of an HC yields only carbon dioxide and water, which do not harm the environment. Indeed, green plants “digest” carbon dioxide by photosynthesis.Carbon dioxide is a necessary ingredient in vegetal life. Animals do not suffer from breathing carbon dioxide unless its concentration in air is such that oxygen is almost absent.Actually, the combustion of HC fuel in combustion engines is never ideal.Besides carbon dioxide and water, the combustion products contain a certain amount of nitrogen oxides (NOx), carbon monoxides (CO), and unburned HCs，all of which are toxic to human health.1.1.1 Nitrogen OxidesNitrogen oxides(NOx) result from the reaction between nitrogen in the air and oxygen. Theoretically, nitrogen is an inert gas. However, the high temperatures and pressures in engines create favorable conditions for the formation of nitrogen oxides. Temperature is by far the most important parameter in nitrogen oxide formation. The most commonly found nitrogen oxide is nitric oxide(NO), although small amounts of nitric dioxide (NO2) and traces of nitrous oxide (N2O) are present. Once released into the atmosphere, NO reacts with the oxygen to form NO2. This is later decomposed by the Suns ultraviolet radiation back to NO and highly reactive oxygen atoms that attack the membranes of living cells. Nitrogen dioxide is partly responsible for smog; its brownish color makes smog visible. It also reacts with atmospheric water to form nitric acid (HNO3), which dilutes in rain. This phenomenon is referred to as “acid rain” and is responsible for the destruction of forests in industrialized countries.Acid rain also contributes to the degradation of historical monuments made of marble.1.1.2 Carbon MonoxideCarbon monoxide results from the incomplete combustion of HCs due to a lack of oxygen.1 It is a poison to human beings and animals who inhale/breathe it. Once carbon monoxide reaches the blood cells, it fixes to the hemoglobin in place of oxygen, thus diminishing the quantity of oxygen that reaches the organs and reducing the physical and mental abilities of affected living beings.1 Dizziness is the first symptom of carbon monoxide poisoning, which can rapidly lead to death. Carbon monoxide binds more strongly to hemoglobin than oxygen. The bonds are so strong that normal body functions cannot break them. People intoxicated by carbon monoxide must be treated in pressurized chambers, where the pressure makes it easier to break the carbon monoxidehemoglobin bonds.1.1.3 Unburned HCsUnburned HCs are a result of the incomplete combustion of HCs.1,2 Depending on their nature, unburned HCs may be harmful to living beings.2 Some of these unburned HCs may be direct poisons or carcinogenic chemicals such as particulates, benzene, or others. Unburned HCs are also responsible for smog:the Suns ultraviolet radiations interact with the unburned HCs and NO in the atmosphere to form ozone and other products. Ozone is a molecule formed of three oxygen atoms. It is colorless but very dangerous, and is poisonous because as it attacks the membranes of living cells, causing them to age prematurely or die. Toddlers, older people, and asthmatics suffer greatly from exposure to high ozone concentrations. Annually, deaths from high ozone peaks in polluted cities have been reported.31.1.4 Other PollutantsImpurities in fuels result in the emission of pollutants. The major impurity is sulfur: mostly found in diesel and jet fuel, but also in gasoline and natural gas.1 The combustion of sulfur (or sulfur compounds such as hydrogen sulfide) with oxygen releases sulfur oxides (SOx). Sulfur dioxide (SO2) is the major product of this combustion. On contact with air, it forms sulfur trioxide, which later reacts with water to form sulfuric acid, a major component of acid rain. It should be noted that sulfur oxide emissions originate from transportation sources but also largely from the combustion of coal in power plants and steel factories. In addition, there is debate over the exact contribution of、natural sources such as volcanoes. Petroleum companies add chemical compounds to their fuels in order to improve the performance or lifetime of engines.1 Tetraethy lead, often referred to simply as “lead,” was used to improve the knock resistance of gasoline and therefore allow better engine performance. However, the combustion of this chemical releases lead metal, which is responsible for a neurological disease called “saturnism.” Its use is now forbidden in most developed countries and it has been replaced by other chemicals.11.2 Global WarmingGlobal warming is a result of the “greenhouse effect” induced by the presence of carbon dioxide and other gases, such as methane, in the atmosphere. These gases trap the Suns infrared radiation reflected by the ground, thus retaining the energy in the atmosphere and increasing the temperature. An increased Earth temperature results in major ecological damages to its ecosystems and in many natural disasters that affect human populations.2Considering the ecological damages induced by global warming, the disappearance of some endangered species is a concern because this destabilizes the natural resources that feed some populations. There are also concerns about the migration of some species from warm seas to previously colder northern seas, where they can potentially destroy indigenous species and the economies that live off those species. This may be happening in the Mediterranean Sea, where barracudas from the Red Sea have been observed.Natural disasters command our attention more than ecological disasters because of the amplitude of the damages they cause. Global warming is believed to have induced meteorological phenomena such as “El Nio,” which disturbs the South Pacific region and regularly causes tornadoes, inundations, and dryness. The melting of the polar icecaps, another major result of global warming, raises the sea level and can cause the permanent inundation of coastal regions and sometimes of entire countries.Carbon dioxide is the result of the combustion of HCs and coal. Transportation accounts for a large share (32% from 1980 to 1999) of carbon dioxide emissions. The distribution of carbon dioxide emissions is shown in Figure 1.1.4Figure 1.2 shows the trend in carbon dioxide emissions. The transportation sector is clearly now the major contributor to carbon dioxide emissions. It should be noted that developing countries are rapidly increasing their transportation sector, and these countries represent a very large share of the world population. Further discussion is provided in the next subsection.The large amounts of carbon dioxide released into the atmosphere by human activities are believed to be largely responsible for the increase in the global Earth temperature observed during the last decades (Figure 1.3).It is important to note that carbon dioxide is indeed digested by plants and sequestrated by oceans in the form of carbonates. However, these natural assimilation processes are limited and cannot assimilate all of the emitted carbon dioxide, resulting in an accumulation of carbon dioxide in the Atmosphere.1.3 Petroleum ResourcesThe vast majority of fuels for transportation are liquid fuels originating from petroleum. Petroleum is a fossil fuel, resulting from the decomposition of living matters that were imprisoned millions of years ago (Ordovician,600400 million years ago) in geologically stable layers. The process is roughly the following: living matters (mostly plants) die and are slowly covered by sediments. Over time, these accumulating sediments form thick layers and transform to rock. The living matters are trapped in a closed space, where they encounter high pressures and temperatures and slowly transform into either HCs or coal, depending on their nature. This process takes millions of years to accomplish. This is what makes the Earths resources in fossil fuels finite. Proved reserves are “those quantities that geological and engineering information indicates with reasonable certainty can be recovered in the future from known reservoirs under existing economic and operating conditions.”5 Therefore, they do not constitute an indicator of the Earths total reserves. The proved reserves, as they are given in the British Petroleum 2001 estimate,5 are given in billion tons in Table 1.1. The R/P ratio is the number of years that the proved reserves would last if the production were to continue at its current level. This ratio is also given in Table 1.1 for each region.5 The oil extracted nowadays is the easily extract able oil that lies close to the surface, in regions where the climate does not pose major problems. It is believed that far more oil lies underneath the Earths crust in regions such as Siberia, or the American and Canadian Arctic. In these regions, the climate and ecological concerns are major obstacles to extracting or prospecting for oil. The estimation of the total Earths reserves is a difficult task for political and technical reasons. A 2000 estimation of the undiscovered oil resources by the US Geological Survey is given in Table 1.2.6 Although the R/P ratio does not include future discoveries, it is significant. Indeed, it is based on proved reserves, which are easily accessible to this day. The amount of future oil discoveries is hypothetical, and the newly discovered oil will not be easily accessible. The R/P ratio is also based on the hypothesis that the production will remain constant. It is obvious, however, that consumption (and therefore production) is increasing yearly to keep up with the growth of developed and developing economies. Consumption is likely to increase in gigantic proportions with the rapid development of some largely populated countries,particularly in the Asia-Pacific region. Figure 1.4 shows the trend in oil consumption over the last 20 years.7 Oil consumption is given in thousand barrels per day (one barrel is about 8 metric tons). Despite the drop in oil consumption for Eastern Europe and the former USSR, the world trend is clearly increasing, as shown in Figure 1.5. The fastest growing region is Asia Pacific, where most of the worlds population lives.An explosion in oil consumption is to be expected, with a proportional increasein pollutant emissions and CO2 emissions.1.4 Induced CostsThe problems associated with the frenetic combustion of fossil fuels are many: pollution, global warming, and foreseeable exhaustion of resources, among others.Although difficult to estimate, the costs associated with these problems are huge and indirect,8 and may be financial, human, or both. Costs induced by pollution include, but are not limited to, health expenses, the cost of replanting forests devastated by acid rain, and the cost of cleaning and fixing monuments corroded by acid rain. Health expenses probably represent the largest share of these costs, especially in developed countries with socialized medicine or health-insured populations. Costs associated with global warming are difficult to assess. They may include the cost of the damages caused by hurricanes, lost crops due to dryness, damaged properties due to floods, and international aid to relieve the affected populations. The amount is potentially huge.Most of the petroleum-producing countries are not the largest petroleum consumingcountries. Most of the production is located in the Middle East, while most of the consumption is located in Europe, North America, and Asia Pacific. As a result, consumers have to import their oil and depend on the producing countries. This issue is particularly sensitive in the Middle East, where political turmoil affected the oil delivery to Western countries in 1973 and 1977. The Gulf War, the IranIraq war, and the constant surveillance of the area by the United States and allied forces come at a cost that is both human and financial. The dependency of Western economies on a fluctuating oil supply is potentially expensive. Indeed, a shortage in oil supplycauses a serious slowdown of the economy, resulting in damaged perishable goods, lost business opportunities, and the eventual impossibility to run businesses.In searching for a solution to the problems associated with oil consumption, one has to take into account those induced costs. This is difficult because the cost is not necessarily asserted where it is generated. Many of the induced costs cannot be counted in asserting the benefits of an eventual solution. The solution to these problems will have to be economically sustainable and commercially viable without government subsidies in order to sustain itself in the long run. Nevertheless, it remains clear that any solution to these problems even if it is only a partial solutionwill indeed result in cost savings, which will benefit the payers.现代交通运输对环境和历史的影响内燃机的发展，车辆发动机的发展，特别是汽车，是现代科技的最伟大的成就之一。汽车为现代社会的发展作出了巨大贡献。满足了日常通行的便利性。汽车行业的快速发展不像其他行业一样，是促使人类从原始安全高度进步的发达工业之一。汽车产业和其服务产业构成了世界经济的支柱，占据了劳动人口的最大份额。然而，在世界各地由于使用大量的汽车引起的并继续给环境和人类的生活造成严重的问题。空气污染，全球变暖，地球上石油资源快速损耗的问题在现在看来至关重要。近几十年来,研究和运输有关的开发活动强调发展高效、清洁和安全的运输。在不久的将来电动车，混合动力电动汽车和燃料电池汽车被提出取代传统的车辆。本章回顾了空气污染的问题，气体排放造成的全球变暖，和石油资源枯竭的问题。同时也简要回顾了电动汽车的历史、混合动力汽车和燃料电池技术。1.1 空气污染目前,所有汽车依赖碳氢化合物燃料的燃烧热获得所需的能源推进。燃烧是一个反应燃料和空气之间的释放热量和燃烧产物的关系。热量转化为机械动力传递到发动机和燃烧产品释放到大气中。碳氢化合物是一种由碳和氢的原子组成的分子。理想情况下,燃烧碳氢化合物的收益率只有二氧化碳和水,不伤害环境。实际上，绿色植物通过光合作用“消化”二氧化碳。二氧化碳是植物生活的必要组成部分。动物呼吸二氧化碳不会导致生病除非在空气中它的浓度过高而导致没有氧气一样。实际上，碳氢化合物燃料的燃烧在内燃机中从来都不是理想的。除了二氧化碳和水，燃烧包含一个特定的产品：大量的氮氧化物(NOx)，一氧化碳(CO)，未燃烧的高碳化合物，所有的这一些对人体健康都是有害的。1.1.1氮氧化物氮氧化物(NOx)与空气中氮气之间的反应结果是氧气。从理论上讲，氮气是一种惰性气体。然而，发动机的高温和高压为氮氧化物的形成创造有利条件。温度是氮氧化物形成的最重要的参数。最常见的氮氧化物是一氧化氮（NO），尽管也有少量的二氧化碳(NO2)和一氧化二氮（N2O）。一旦释放到大气中，一氧化氮与氧气形成NO2。后来被太阳的紫外线分解辐射回到一氧化氮和高度活性氧原子攻击细胞膜的活细胞。二氧化氮是烟雾的形成部分，它的存在使烟雾形成可见的褐色。它还与大气中的水反应形成硝酸（HNO3）稀释在雨中。这种现象被称为“酸雨”，就是这种物质在工业化国家破坏森林。酸雨也有助于大理石古迹的退化。1.1.2一氧化碳碳氢化合物由于缺少氧气导致不完全燃烧的结果是产生一氧化碳。一旦呼吸/吸入它对人类和动物来说是毒药。一旦一氧化碳到达血液细胞，它就会与血红蛋白中的氧结合，从而减少到达器官的氧气含量，影响生物的身体和精神能力。1.1.3未燃碳氢化合物未燃碳氢化合物导致碳氢化合物不完全燃烧的结果。根据其本质上来讲，未燃的碳氢化合物可能有害生物。部分这些未燃的碳氢化合物有可能直接含有有毒颗粒、苯或其他致癌化学物质危害人体健康。未燃的碳氢化合物还会产生烟雾，太阳的紫外线辐射与未燃的碳氢化合物有还有大气中的一氧化氮形成臭氧臭氧和其他产品。臭氧是一种由三个氧原子组成的分子。它是无色的，但非常危险，是有毒的。因