首页
登录
职称英语
Although recent years have seen substantial reductions in noxious pollutants
Although recent years have seen substantial reductions in noxious pollutants
游客
2023-08-09
41
管理
问题
Although recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing. Consequently, more than 100 cities in the United States still have levels of carbon monoxide, particulate matter, and ozone(generated by photochemical reactions with hydrocarbons from vehicle exhaust)that exceed legally established limits. There is a growing realization that the only effective way to achieve further reductions in vehicle emissions—short of a massive shift away from the private automobile—is to replace conventional diesel fuel and gasoline with cleaner-burning fuels such as compressed natural gas, liquefied petroleum gas, ethanol, or methanol.
All of these alternatives are carbon-based fuels whose molecules are smaller and simpler than those of gasoline. These molecules burn more cleanly than gasoline, in part because they have fewer, if any, carbon-carbon bonds and the hydrocarbons they do emit are less likely to generate ozone. The combustion of larger molecules, which have multiple carbon-carbon bonds involves a more complex series of reactions. These reactions increase the probability of incomplete combustion and are more likely to release uncombusted and photochemically active hydrocarbon compounds into the atmosphere. On the other hand, alternative fuels do have drawbacks. Compressed natural gas would require that vehicles have set of heavy fuel tanks—a serious liability in terms of performance and fuel efficiency—and liquefied petroleum gas faces fundamental limits on supply.
Ethanol and methanol, on the other hand, have important advantages over other carbon-based alternative fuels: they have higher energy content per volume and would require minimal changes in the existing network for distributing motor fuel. Ethanol is commonly used as a gasoline supplement, but it is currently about twice as expensive as methanol, the low cost of which is one of its attractive features. Methanol’ s most attractive feature, however, is that it can reduce by about 90 percent the vehicle emissions that form ozone, the most serious urban air pollutant.
Like any alternative fuel, methanol has its critics. Yet much of the criticism is based on the use of "gasoline clone" vehicles that do not incorporate even the simplest design improvements that are made possibly with the use of methanol. It is true, for example, that a given volume of methanol provides only about one-half of the energy that gasoline and diesel fuel do; other things being equal, the fuel tank would have to be somewhat larger and heavier. However, since methanol-fuelled vehicles could be designed to be much more efficient than "gasoline clone" vehicles fuelled with methanol, they would need comparatively less fuel. Vehicles incorporating only the simplest of the engine improvements that methanol makes feasible would still contribute to an immediate lessening of urban air pollution. [br] It can be inferred that the author of the text most likely regards the criticism of methanol as______.
选项
A、flawed because of the assumptions on which it is based
B、inapplicable because of an inconsistency in the critics’ arguments
C、misguided because of its exclusively technological focus
D、inaccurate because it ignores consumers’ concerns
答案
A
解析
细节题。根据criticism of methanol定位到最后一段Like any alternativefuel.methanol has its critics.Yet much of the criticism is based on the use of“gasolineclone”vehicles that do not incorporate even the simplest design improvements that aremade possibly with the use of methanol.“和其他的替代燃料一样,甲醇也遭到了非难。可大多数批评都建立在使用‘汽油系列’的车辆不进行最简单的设计改进以可能使用甲醇燃料的基础上。”批评的不足之处在于假设的基础,所以答案选A。
转载请注明原文地址:https://tihaiku.com/zcyy/2910050.html
相关试题推荐
[originaltext]FacebookfounderMarkZuckerbergrecentlysurprisedChineses
[originaltext]FacebookfounderMarkZuckerbergrecentlysurprisedChineses
[originaltext]Untilrecently,blindandvisuallyimpairedstudentsinKenya
[originaltext]Inthecaseofmobilephones,changeiseverything.Recentre
[originaltext]Inthecaseofmobilephones,changeiseverything.Recentre
[originaltext]Inthecaseofmobilephones,changeiseverything.Recentre
[originaltext]Recentlyafive-yearstudywasconductedbytheCenterforCh
[originaltext]Recentlyafive-yearstudywasconductedbytheCenterforCh
[originaltext]Recentlyafive-yearstudywasconductedbytheCenterforCh
[originaltext]M:Patricia,whathaveyoubeendoingrecently?W:(5)I’mdoingc
随机试题
•Lookatthenotesbelow.•Youwillhearawomancallingtoaskforaclaim.
SpeakerA:DoyoumindifIkeeppetsinthisbuilding?SpeakerB:______A、Iwou
ThepassageonthefollowingpageshassevensectionsA-G.Choosethecorrecthe
Thegovernmentofficialcanhardlyfindsufficientgroundsonwhichtobasehis
高等学校专业设置和调整的原则与指导思想是什么
督脉之络穴位于()A.头项部 B.上腹部 C.下腹部 D.胸胁部
小赵和小刘是非常熟悉的好朋友,两家相距很近,疫情期间,小赵曾给本单位同处室的同事
卖出套期保值的目的是防止现货市场价格上涨。()
A.嗜酸性粒细胞 B.中性粒细胞 C.嗜碱性粒细胞 D.血小板 E.淋巴
关于氯沙坦临床应用及不良反应错误的表达是A、可用于各型高血压 B、3~6周后血
最新回复
(
0
)