2. 考研
  3. Copying Birds May Save Aircraft Fuel Both Boeing and Airbus have trumpeted the efficiency of their newest aircraft, the 787

Copying Birds May Save Aircraft Fuel Both Boeing and Airbus have trumpeted the efficiency of their newest aircraft, the 787

admin2014-06-13  24
问题                     Copying Birds May Save Aircraft Fuel
    Both Boeing and Airbus have trumpeted the efficiency of their newest aircraft, the 787 and A350 respectively. Their clever designs and lightweight composites certainly make a difference. But a group of researchers at Stanford University, led by Ilan Kroo, has suggested that airlines could take a more naturalistic approach to cutting jet-fuel use, and it would not require them to buy new aircraft.
    The answer, says Dr Kroo, lies with birds. Since 1914, scientists have known that birds flying in formation—a V-shape—expend less energy. The air flowing over a bird’s wings curls upwards behind the wingtips, a phenomenon known as upwash. Other birds flying in the upwash experience reduced drag, and spend less energy propelling themselves. Peter Lissaman, an aeronautics expert who was formerly at Caltech and the University of Southern California, has suggested that a formation of 25 birds might enjoy a range increase of 71 % .
    When applied to aircraft, the principles are not substantially different. Dr Kroo and his team modelled what would happen if three passenger jets departing from Los Angeles, San Francisco and Las Vegas were to assemble over Utah, assume an inverted V-formation, occasionally change places so all could have a turn in the most favourable positions, and proceed to London. They found that the aircraft consumed as much as 15% less fuel (coupled with a reduction in carbon-dioxide output). Nitrogen-oxide emissions during the cruising portions of the flight fell by around a quarter.
    There are, of course, knots to be worked out. One consideration is safety, or at least the perception of it. Would passengers feel comfortable travelling in companion? Dr Kroo points out that the aircraft could be separated by several nautical miles, and would not be in the intimate groupings favoured by display teams like the Red Arrows. A passenger peering out of the window might not even see the other planes. Whether the separation distances involved would satisfy air-traffic-control regulations is another matter, although a working group at the International Civil Aviation Organisation has included the possibility of formation flying in a blueprint for new operational guidelines.
    It remains to be seen how weather conditions affect the air flows that make formation flight more efficient. In zones of increased turbulence, the planes’ wakes will decay more quickly and the effect will diminish. Dr Kroo says this is one of the areas his team will investigate further. It might also be hard for airlines to co-ordinate the departure times and destinations of passenger aircraft in a way that would allow them to gain from formation flight. Cargo aircraft, in contrast, might be easier to reschedule, as might routine military flights.
    As it happens, America’s armed forces are on the case already. Earlier this year the country’s Defence Advanced Research Projects Agency announced plans to pay Boeing to investigate formation flight, thought the programme has yet to begin. There are reports that some military aircraft flew in formation when they were low on fuel during the Second World War, but Dr Lissaman says they are unsubstantiated. "My father was an RAF pilot and my cousin the skipper of a Lancaster lost over Berlin, "he adds. So he should know.
Findings of the Stanford University researchers will promote the sales of new Boeing and Airbus aircraft.
选项 A、True
B、False
答案B
解析 文章第一段首先提到波音和空客在宣传其飞机(波音787和空客A350)的效能。但随后便告诉我们：斯坦福大学的研究者认为，航空公司可以采用更为自然主义的方式来节能，并不需要买新飞机。所以该题“Findings of the Stanford University researchers will promote the sales of new Boeing and Airbus aircraft．”(斯坦福大学研究者的发现将有助于波音和空客的飞机销售)为错误表述。这里还有两点需要指出：其一，一般情况下，这种说明文类型文章的开头方式有二：开门见山。直奔主题；略作“铺垫”，再转向主题。判断的方式是看第一段的后面或是第二段有没有but、however、yet等表示转折关系的关联词或是not、fail to等表示否定的表达方式。如没有，文章的首句可能 是文章的主题，如有，文章的首句则为“铺垫”而非主题。其二，“naturalistic approach”中的“naturalistic”意为“自然主义的，效法自然的”，原来常用来表示文学艺术作品中一种照搬自然．无取舍的流派或手法，现在也常用来表示人们师法自然的观念或行为。另外，由于“suggest”一词后面的从句中没有使用should或是原形动词而是使用了一般时态，这里的“suggest”意思是“认为”而不是“建议”。
转载请注明原文地址:https://kaotiyun.com/show/5mK4777K
0

考研英语一

相关试题推荐
随机试题
最新回复(0)