In the late 1960s, many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.
Skyscrapers are also lavish consumers, and wasters, of electric power. In one recent year, the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120, 000 kilowatts-enough to supply the entire city of Albany, New York, for a day.
Glass-walled skyscrapers can be especially wasteful. The heat loss through a wall of half-inch plate glass is more than ten times that through a typical masonry wall filled with insulation board. To lessen the strain on heating and air-conditioning equipment, builders of skyscrapers have begun to use double-glazed panels of glass, and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However, mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.
Skyscrapers put a severe strain on a citys sanitation facilities, too. If fully occupied, the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stanford, Connecticut , which has a population of more than 109, 000.
八年级英语同义句转换练习
九年级英语完成句子专项练习
冠词考向分析与考点训练
九年级英语上词汇专项练习
点击重点句式链接中考考点(三)
九年级英语上完成句子专项练习
八年级英语上重点词组练习
点击重点句式链接中考考点(二)
英语中考语法(五)动词专题复习(1)
九年级英语上动词时态练习
八年级英语单项选择专项练习一
八年级英语上单选专项练习二
八年级英语上单选专项练习一
英语语法大全整本收录(五)动词
击重点句式链接中考考点(一)
八年级英语同义句转换
八年级英语宾语从句练习
英语课外辅导:中考 V-ing 形式考点分析
中考英语精选真题讲解
中考英语短文填空练习二
英语语法大全整本收录(四)形容词和副词
英语语法大全整本收录(二) 冠词和数词
中考英语完型填空之答题技巧:精选巧选
英语中考语法(一)名词专题复习(1)
初中英语常用量词词组及其它词组
英语语法大全整本收录(七) 动词不定式
初中教材中的八个IT句型
八年级英语用词的适当形式填空
八年级英语用词适当形式填空
英语宾语从句专题复习
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |