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.
新人教版英语八下《Unit 10 It’s a nice day, isn’t it》ppt课件包(含素材文件)1
人教新目标版英语八下《Unit 7 Would you mind turning down the music》ppt课件(一)
人教新目标版英语八下《Unit 9 Have you ever been to an amusement park》ppt课件
人教新目标版英语八下《Unit 3 What were you doing when the UFO arrived》ppt课件(三)
人教新目标版英语八下《Unit 8 Why don’t you get her a scarf》ppt课件(四)
人教新目标版英语八下《Unit 3 What were you doing when the UFO arrived》ppt课件(一)
人教新目标版英语八下《Unit 6 How long have you been collecting shells》ppt课件(一)
人教新目标版英语八下《Unit 7 Would you mind turning down the music》ppt课件(二)
新人教版英语八下《Unit 10 It’s a nice day, isn’t it》ppt课件包(含素材文件)
人教新目标版英语八下《Unit 3 What were you doing when the UFO arrived》ppt期末复习课件
人教新目标版英语八下《Unit 7 Would you mind turning down the music》ppt课件(四)
人教新目标版英语八下《Unit 7 Would you mind turning down the music》ppt课件(三)
新人教版英语八下《Unit 1 Will people have robots》ppt课件1
人教新目标版英语八下《Unit 2 What should I do》ppt课件(一)
人教新目标版英语八下《Unit 4 He said I was hard-working》ppt课件(四)
人教新目标版英语八下《Unit 9 Have you ever been to an amusement park》ppt课件(二)
人教新目标版英语八下《Unit 8 Why don’t you get her a scarf》ppt课件(五)
人教新目标版英语八下《Unit 10 It’s a nice day, isn’t it》ppt课件包(含声音素材)
人教新目标版英语八下《Unit 8 Why don’t you get her a scarf》ppt课件(二)
人教新目标版英语八下《Unit 3 What were you doing when the UFO arrived》ppt课件(二)
人教新目标版英语八下《Unit 5 If you go to the party, you’ll have a great time》ppt课件
人教新目标版英语八下《Unit 3 What were you doing when the UFO arrived》ppt课件
人教新目标版英语八下《Unit 3 What were you doing when the UFO arrived》ppt课件(四)
新人教版英语八下《Unit 1 Will people have robots》ppt复习课件1
人教新目标版英语八下《Unit 9 Have you ever been to an amusement park》ppt课件(五)
人教新目标版英语八下《Unit 9 Have you ever been to an amusement park》ppt课件(一)
人教新目标版英语八下《Unit 9 Have you ever been to an amusement park》ppt课件(四)
人教新目标版英语八下《Unit 4 He said I was hard-working》ppt课件(六)
新人教版英语八下《Unit 2 What should I do》(第1课时)ppt课件
人教新目标版英语八下《Unit 4 He said I was hard-working》ppt课件(三)
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