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.
2016春牛津译林版英语七下Unit 5《Amazing things》(第5课时)word导学案
2016春牛津译林版英语七下Unit 3《Welcome to Sunshine Town》(Reading 2)word教案
2016春牛津译林版英语七下Unit 5《Amazing things》(第2课时)word导学案
2016春牛津译林版英语七下Unit 5《Amazing things》(Reading 2)word教案
2016春牛津译林版英语七下Unit 5《Amazing things》(Reading 1)word教案
2016春牛津译林版英语七下Unit 4《Finding your way》(第2课时)word导学案
2016春牛津译林版英语八下Unit 8《A green world》(integrasted skills)word导学案
2016春牛津译林版英语七下Unit 3《Welcome to Sunshine Town》(Reading 1)word教案
2016春牛津译林版英语八下Unit 7《International charities》(welcome to unit)word导学案
2016春牛津译林版英语七下Unit 3《Welcome to Sunshine Town》word导学案4
2016春牛津译林版英语七下Unit 3《Welcome to Sunshine Town》word导学案5
2016春牛津译林版英语七下Unit 4《Finding your way》(Reading)word教案
2016春牛津译林版英语七下Unit 5《Amazing things》(第4课时)word导学案
2016春牛津译林版英语七下Unit 4《Finding your way》(第3课时)word导学案
2016春牛津译林版英语七下Unit 6《Outdoor Fun》(Integrated skills)word导学案
2016春牛津译林版英语八下Unit 8《A green world》(welcome)word导学案
2016春牛津译林版英语八下Unit 7《International charities》(Task)word导学案
2016春牛津译林版英语七下Unit 4《Finding your way》(Grammar)word教案
2016春牛津译林版英语七下Unit 3《Welcome to Sunshine Town》word导学案7
2016春牛津译林版英语七下Unit 4《Finding your way》(第1课时)word导学案
2016春牛津译林版英语七下Unit 6《Outdoor Fun》word单元教案
2016春牛津译林版英语七下Unit 4《Finding your way》(第4课时)word导学案
2016春牛津译林版英语七下Unit 3《Welcome to Sunshine Town》(Welcome to the unit)word教案
2016春牛津译林版英语七下Unit 4《Finding your way》(In tegrated skills and Study skills)word教案
2016春牛津译林版英语七下Unit 6《Outdoor Fun》word单元知识总结
2016春牛津译林版英语七下Unit 5《Amazing things》(Study skills)word教案
2016春牛津译林版英语八下Unit 8《A green world》(Reading2)word导学案
2016春牛津译林版英语七下Unit 4《Finding your way》(第5课时)word导学案
2016春牛津译林版英语八下Unit 7《International charities》(Task)word导学案1
2016春牛津译林版英语八下Unit 7《International charities》(Reading 1)word导学案
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