首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
All competitive ski and snowboarding events now take place largely on man-made snow. Unlike its natural counterpart, the machine
All competitive ski and snowboarding events now take place largely on man-made snow. Unlike its natural counterpart, the machine
admin
2013-07-20
19
问题
All competitive ski and snowboarding events now take place largely on man-made snow. Unlike its natural counterpart, the machine-made white stuff can be carefully tweaked to make a more durable and consistent surface: one perfect for record-breaking attempts. Snow-making equipment is viewed as essential in most ski areas to guarantee coverage throughout the season. Nowadays, "natural snow is a bonus," says Rich Brown of snow-making technology company York Snow in Victor, New York.
The snow "cannons" or "guns" that manufacture snow mimic the natural formation of snowflakes. Snow machines typically force pressurized water through a nozzle (喷嘴), breaking it into a mist of tiny droplets, and then use compressed air or fans to blast them into the air. As the droplets cool, the molecules line, and crystallize into ice particles. The art to snow-making is adjusting the water and air to ensure that the water drops are small enough and sent far enough that they will freeze before they hit the ground. If the air temperature is quite high, for example, dropping the water content and upping the air would create smaller particles that are more likely to freeze. Snow-making machines also frequently incorporate nucleating agents (成核剂)in the water: small quantities of materials such as bacterial protein, on to which the water molecules attach and freeze. By triggering freezing, these agents raise the temperature at which snow can be made.
Many resorts now use sophisticated computer systems that automatically adjust the air and water output from snow machines based on air temperature, humidity and wind, says Brown. For race courses, experts adjust man-made snow to create a tough, fast and icy course rather than a powdery one. A ski course is also heavily groomed and often intentionally flooded to create patches of ice; these factors generally determine the speed of a race.
Snow manufacturing is in great demand. Some predict that the need for snow will rocket with, the warming effects of climate change, which are already pushing snow lines up the Alps. But this comes with environmental costs, says Michel Revaz, of the International Commission for Protection of the Alps (ICPRA). Making snow chews up energy and water, and can rob rivers and creeks in the surrounding ecosystems. One way to conserve the mountain environment, Revaz says, would be to reuse winter sports competition facilities rather than building new ones.
The reason for the increasing demand of man-made snow may be attributed to______ .
选项
答案
the warming effects of climate change
解析
细节辨认题。本题考查人造雪需求增加的原因。定位句明确指出,人造雪大有市场,接着提到这种需求在迅速增加,这与全球气候变暖有关。故答案为the warmingeffects of climate change。
转载请注明原文地址:https://kaotiyun.com/show/t7n7777K
0
大学英语六级
相关试题推荐
Halloweenusedtobesomethingquitedifferentfromthecelebrationofsugarygreedthatgoesontoday.Earlierinthiscent
Somewomen______________________(本来在工作中能够有一份不错的收入)insteadofstayinghome,buttheydecidednottoworkforthesakeofthe
TheBushadministrationisgivingpublicschooldistrictsbroadnewlatitudetoexpandthenumberofsingle-sexclasses,andeve
A、Irrelevant.B、Straightforward.C、Ridiculous.D、Confrontational.D录音提到,第二个问题更有挑衅性(moreconfrontational),提问“实施这个计划的钱从哪来”这个问题的记者似
Comparisonsweredrawnbetweenthedevelopmentoftelevisioninthe20thcenturyandthediffusionofprintinginthe15thand1
Adulteducationdevelopsfastrecentlypartlybecause______.Whatissaidabouttherelationshipbetweentheseeducationorgan
A、Toreplacephysicaltherapy.B、Tocontrolbrainseizures.C、Topreventheartdisease.D、Torelievetension.DA的表述太过绝对,可排除。问题询问
A、Herpriorschooling.B、Hernameandresidenceaddress.C、Herage.D、Herdrivingrecord.B事实细节题男士认为,她只需要确认姓名与住址即可。
ThewaysBushesworkedandlivedinWhiteHouseareunlikethoseoftheClintons.Laura’sdaughterJennahasgotaPh.D.degre
随机试题
防范是社会治安综合治理的首要环节。()
能够经阴道自然分娩的胎方位是
患儿,男,7岁,下前牙长出“双排牙”,经检查,前排牙松动I度,后排牙位于牙列舌侧。最可能的诊断是
肺气肿时,心脏浊音界的改变多为
具有行气、消积功效的药物是
小茴香的功效为
隔室的设置与铠装型一样,但隔室的隔板用绝缘材料,结构紧凑是什么金属封闭开关设备特点?()
诉讼代理人是代理当事人进行民事诉讼活动的人,下列能够作为诉讼代理人的包括()。
已知比邻全体学生的某项测验分数为正态分布,σ2=16,从总体中抽取16名被试,求出了他们的平均分数为38分,则总体平均数0.95的置信界限是()
打开数据库的命令是()。
最新回复
(
0
)