在线英语听力室

SSS 2011-11-16

时间:2011-12-02 06:02:39

搜索关注在线英语听力室公众号:tingroom,领取免费英语资料大礼包。

(单词翻译)

 Ever wander through a supermarket and past the open refrigerated cases that house cream cheese, butter and OJ? The refrigerated shelves are protected by jets of air that blow across the front. These jets form an air shield to keep the warm air out.

 
Trouble is, it doesn't always work. The cases use extra energy to cool the air that leaks in. So researchers tested the ubiquitous cases. They shot air across the front to try out a variety of speeds, angles and other factors. They used a tracer gas to measure warm air infiltration1.
 
And they found that the key players are the angle of the air grills2 and what's called a Reynolds number—which involves the air jet's speed and density3 and the jet's turbulence4.
 
By adjusting these variables, they were able to get a ten percent reduction in warm air infiltration. Which the researchers say could save $100 million worth of electricity each year. The research was published in the journal Applied5 Thermal6 Engineering. 
 
The researchers have designed a system so that fridge case manufacturers can optimize7 their companies' designs. And save us all some cold cash.
 
Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.

分享到:

Error Warning!

出错了

Error page: /?aid=163935&mid=3
Error infos: Got error 28 from storage engine
Error sql: select `l`.`tag`,`l`.`index`,`l`.`level_id`,`b`.`id`,`b`.`word`,`b`.`spell`,`b`.`explain`,`b`.`sentence`,`b`.`src` from `new_wordtaglist` `l` left join `new_word_base` `b` on `l`.`tag`=`b`.`word` where `l`.`arc_id`='163935' and `l`.`level_id`>='' group by `b`.`word` order by `l`.`index` asc

本文本内容来源于互联网抓取和网友提交,仅供参考,部分栏目没有内容,如果您有更合适的内容,欢迎 点击提交 分享给大家。