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.
儿童绘本故事ppt:皮球去野餐
90本牛津英语阅读树绘本PDF(一)04
90本牛津英语阅读树绘本PDF(一)07
儿童绘本故事ppt
90本牛津英语阅读树绘本PDF(一)02
90本牛津英语阅读树绘本PDF(一)01
儿童绘本故事ppt:这个感觉怎么样?
儿童绘本故事在线阅读:牛的缰绳
儿童绘本故事ppt:小丑学校
儿童绘本故事在线阅读:作为一个孩子是不容易的
儿童绘本故事在线阅读:球类打架的日子
90本牛津英语阅读树绘本PDF(一)03
少儿绘本故事书推荐:在夜晚
少儿绘本故事书推荐:鲍勃去看牙医
少儿英语教育的四大误区
儿童绘本故事在线阅读:在植树节
少儿绘本故事书推荐:球类打架的日子
90本牛津英语阅读树绘本PDF(一)11
90本牛津英语阅读树绘本PDF(一)10
90本牛津英语阅读树绘本PDF(一)09
少儿绘本故事书推荐:我的朋友,大象
英语早教什么时候开始?怎样是正确的双语教育?
少儿绘本故事书推荐:猫和玉米
儿童绘本故事在线阅读:工作的狗
十大最受欢迎的萝莉英语名
90本牛津英语阅读树绘本PDF(一)05
少儿绘本故事书推荐:体检
儿童绘本故事在线阅读:这个感觉怎么样?
少儿绘本故事书推荐:牛的缰绳
如何做好英语亲子阅读?
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |