新闻万花筒：VOA视角之新技术降低废金属分离成本
Spiiker新闻万花筒，VOA新闻，带您看世界，听世界， 感受世界的点点滴滴。 练听力，提能力，小编与您共努力！ Scrap-Metal Separation May Become Cheaper According to the Environmental Protection Agency, the United States throws 14.8 million tons of scrap metal into landfills every year. One of the main reasons is the difficulty of large-scale separation of non-ferrous metals. Scientists at the University of Utah now say they have solved that problem. Recycling metals is much cheaper than extracting them from the ore. But chopping up old cars, appliances or industrial equipment results in a mixture of different metal parts. Iron and steel are easily separated with strong magnets, while others, such as copper, aluminum and titanium, either end up in landfills or are shipped to countries with cheap labor to pick out the different metal by hand. Researchers at the University of Utah now say they have developed a method for mechanically separating light metals with high degree of accuracy. Don Eggert of O2M Technologies, which partnered with the school in developing the technology, said the system is based on the fact that all metals react to a strong magnetic field. “When the metal falls through the field, even it’s non-ferrous, it’s not attracted to the magnet, but the magnet causes there to be an electric current inside the metal and that causes the metal to have a magnetic field itself, which interacts with the magnetic field that it’s falling through and pushes it to the side,” said Eggert. Eggert said rapid change in the frequency of the magnetic field results in metal pieces falling into different bins. “So, for example, if we want to separate aluminum and copper we hit the right frequency for it and the aluminum would push more away from the magnet than the copper will," he said. "So the copper falls straight down, the aluminum falls into a different bucket.” This is just one of the technologies for separating different metals but Eggert says it is much cheaper to build since it requires only one large circular magnet and a frequency controller. “What we have calculated so far is that the expense to value ratio -- that is how quickly you can pay back the cost of the technology over time - we’re currently estimating it to be less than one year.” At the moment, the separator works only with pellets up to one centimeter wide. Researchers are now building a bigger magnet with a wider cut to accommodate larger metal parts. They hope to have it installed at a metal shredding facility sometime this year, where they will be able to test it in a real-life environment. 词汇解析 swallow 难度：3星常用词汇，属常用6000词 英汉解释 n.燕子；吞咽；一次吞咽的量 v.忍受；吞下；咽下；轻信；不流露感情；收回 参考例句 用作名词 (n.) There are many swallows flying in the sky. 天空中有许多燕子。 1用作动词 (v.) They can't treat me like that; I'm not going to swallow it. 他们不能这样对待我，我忍不下这口气。 ************************ identify 难度：4星核心词汇，属常用3000词 英汉解释 vt.鉴定；识别，辨认出，认出；认明；把…看成一样 vi.认同；感同身受 参考例句 用作及物动词 (vt.) The test can identify the presence of abnormalities in the unborn child. 这项化验能鉴定胎儿是否有不正常现象。 用作不及物动词 (vi.) I identified with the heroine of the novel. 我与小说中的那个女主人公感同身受。 ************************ poverty 难度：4星核心词汇，属常用3000词 英汉解释 n.贫困；贫乏；劣质 参考例句 用作名词 (n.) They were handicapped by (a) poverty of resources. 他们因资源短缺处境窘迫。 ************************ repeatedly 难度：2星扩展词汇，属常用10000词 英汉解释 adv.重复地；再三地 参考例句 用作副词 (adv.) He drew a long breath and repeatedly chanted the name of Rama, every word showering nectar into the hearts of the devotees. 他深深地吸了一口气，重复地唱颂着罗摩的名字，每一个字都像甘露般地洒落在奉献者的心里。 B. However, in order to restore peace and social order, individual states or the international community has repeatedly used force in history. 然而，历史上为了恢复和平和社会秩序，个别的国家或国际社会再三地使用武力。 ************************ rescue 难度：4星核心词汇，属常用3000词 英汉解释 vt.营救；援救 n.营救；救援 参考例句 用作及物动词 (vt.) The government has rescued the firm from bankruptcy by giving them a grant. 政府拨款给这家公司使其免于破产。 用作名词 (n.) Rescue workers rushed to the site of the plane crash. 抢救人员冲向飞机坠毁的现常 ************************ restrict 难度：4星核心词汇，属常用3000词 英汉解释 vt.限制；约束 参考例句 用作及物动词 (vt.) In a move to restrict imports, the government raised custom duties. 政府在限制进口的措施中提高了关税。 ************************ approve 难度：4星核心词汇，属常用3000词 英汉解释 v.批准；赞成；同意；称许 参考例句 用作动词 (v.) I approve of your trying to earn some money, but please don't neglect your studies. 我同意你去挣一些钱，可是请不要误了功课。 No teacher can approve of cheating in exams. 任何教师都不能允许考试作弊。 See more information, you can visit us 英语口语测试 http://www.spiiker.com/daily/
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