Có 140+ tài liệu thuộc chủ đề "nghiên cứu môi trường"
tailieu.vn Xem trực tuyến Tải xuống
Rubber performs best on deep, well-drained soils with a pH of less than 6.5 (in the 4.5 to 7.5 range).. Thus, while in China rubber planta- tions are found on latosols and lateritic red soils, in Brazil—the primary center of diversity—rubber grows on red yellow podosols. There should be high at- mospheric humidity in the order of 80 percent with...
tailieu.vn Xem trực tuyến Tải xuống
ore output was expected to be in the range of 100 to 105 million metric tons per year by 2010. A further limited increase in iron-ore production was projected to the year 2020 without a significant expansion of the resource base. The Noril’sk-Talnakh deposit in Rus- sia is not only the world’s richest nickel deposit but also one of the...
tailieu.vn Xem trực tuyến Tải xuống
Field studies suggest that sandstone constitutes ap- proximately 30 percent of the three principal types of sedimentary rock, exceeding the abundance of lime- stone (approximately 20 percent) but less commonly seen than shale (approximately 50 percent).. It has been used historically as a build- ing material in many famous structures, from ancient times to the present day.. In the geologic...
tailieu.vn Xem trực tuyến Tải xuống
Sedimentary processes occur only at the Earth’s sur- face, because they are driven by various components of the hydrologic and biologic cycles. These processes create many of the important resources used by humans.. This is accomplished through mechani- cal means such as freezing and thawing, plant-root wedging, differential heating of rocks, and crystal growth in rock cracks. Chemical weathering, on...
tailieu.vn Xem trực tuyến Tải xuống
evaporation basin for the drainage waters of the west- ern San Joaquin Valley. Because of interest in saving some of Northern California’s disappearing wetlands, water that entered the reservoir was di- verted and used to preserve wetlands in the adjacent Kesterson National Wildlife Refuge in Merced County, California.. By 1983 the incidence of embryo deformity and mortality among aquatic birds...
tailieu.vn Xem trực tuyến Tải xuống
Lower-grade silicon metals, in the form of ferro- silicon and other silicon metals, are used in other in- dustrial applications. Ferrosilicon is used as an alloy- ing element in aluminum, steel, brass, and bronze, as well as in the chemical industry. “Silicon.” In Chemistry of the Elements. However, be- ginning in 2000, the use of silver in photography declined significantly...
tailieu.vn Xem trực tuyến Tải xuống
Proceedings of the First International Soda Ash Conference: Utilization of Nat- ural Resources of Sodium Carbonate into the Next Century.. Soil is a product of the physical and chemical break- down of the Earth’s surface into small fragments, in- cluding sand, silt, and clay. Soil is also the product of organic matter decomposition—the composting of dead plant and animal debris....
tailieu.vn Xem trực tuyến Tải xuống
Moisture content is defined as the ra- tio of “the weight of water present in a soil sample” to “the weight of dry soil.” Mois- ture content is about 15 to 20 percent for coarse soils and 80 to 100 percent for clays.. Based on these data, each par- ticle diameter is plotted in terms of the. The lower limit...
tailieu.vn Xem trực tuyến Tải xuống
the world population is predicted to reach 10 billion by the middle of the twenty-first century, while the world’s two largest countries by population (China and India) are expected to increase their per capita energy use by three to five times during the same time.. The world is in the process of transitioning to an al- ternative energy future, with...
tailieu.vn Xem trực tuyến Tải xuống
Volume/capacity bbl 7,056 cubic inches. Volume/capacity bbl 31 to 42 gallons. Volume/capacity bsh or bu 2,747.715 cubic inches 1.278 bushels, struck measure Bushel. Volume/capacity bsh or bu 2,150.42 cubic inches 35.238 liters. Centigram Mass/weight cg 0.15 grain. Centimeter, cubic Volume/capacity cm 3 0.061 cubic inch. Centimeter, square Area cm 2 0.155 square inch. Cup Volume/capacity C 250 milliliters. Deciliter Volume/capacity...
tailieu.vn Xem trực tuyến Tải xuống
Rod, square Area rd 2 25.293 square meters. Tablespoon Volume/capacity T or tb 3 teaspoons. 4 fluid drams. Teaspoon Volume/capacity t or tsp 0.33 tablespoon. 1.33 fluid drams Ton. Mass/weight t 2,240 pounds. 1.12 net tons 1.016 metric tons Ton. Mass/weight t 1,000 kilograms. 2,204.62 pounds 0.984 gross ton 1.102 net tons Ton. Mass/weight t 2,000 pounds. 0.893 gross ton...
tailieu.vn Xem trực tuyến Tải xuống
South Korea. Beginning in the late twentieth century, South Korea’s economy rapidly expanded, ranking second interna- tionally in growth, because of industrial development and income from such resources as semiconductors.. Because South Korea lacks sufficient metal and min- eral resources, government and business representa- tives seek agreements with North Korean officials to extract and use resources from that country’s abun-...
tailieu.vn Xem trực tuyến Tải xuống
In 2009, British scientists presented a design for a gravity tractor that would fly close to an asteroid sur- face and, through gravitational influence alone, over perhaps fifteen years, make changes in the orbital path of such a body. Space Enterprise: Living and Working Offworld in the Twenty-first Century. Celestial Navigation in the GPS Age. Energy Strategies—Toward a Solar Future:...
tailieu.vn Xem trực tuyến Tải xuống
The piston was connected to a rod that emerged from the top of the engine, and steam was fed into the cylinder below the piston. A chain connected the piston rod to one end of a piv- oted beam suspended above the engine, and the other end of the beam was connected to a pump that drew water up from...
tailieu.vn Xem trực tuyến Tải xuống
At Founex, and again at Stockholm, the de- veloping countries of the south charged the north with using environmental issues to restrict their eco- nomic growth. Another dispute that surfaced at Stockholm was a result of the Cold War. The Stockholm Conference was attended by 114 coun- tries, representing the larger part of the world’s popu- lation. The 109-point Stockholm...
tailieu.vn Xem trực tuyến Tải xuống
The use of heavy machinery in the twentieth century led to an enormous expansion of dam construction, especially in the United States and Russia.. In recent years, a growing recognition has devel- oped in the United States that certain dams should be considered for demolition because of problems with salmon runs. and changes in the temperature of the water that...
tailieu.vn Xem trực tuyến Tải xuống
the mole- cule forms a bridge between the water-soluble sulfo- nate end and the grease-soluble carbon end, allowing greasy dirt to be rinsed away. “Sulfur.” In Chemistry of the Elements. “Sulfur.” In Industrial Minerals and Rocks: Commodities, Markets, and Uses.. “Group 16: The Chalcogens—Oxygen, Sulfur, Selenium, Tellurium, and Polonium.” In Main Group Chemistry. New York: Wiley, 2000.. Sulfur in the...
tailieu.vn Xem trực tuyến Tải xuống
had expressed interest in the project, but a dispute over the ownership of genetic resources led to a de- lay. Space in the vault is available free of charge to all govern- ments and institutions, and the GCDT pays packaging and shipping costs for developing countries. Seeds must have originated in the depositor’s country or be freely available under provisions...
tailieu.vn Xem trực tuyến Tải xuống
Instead, the global recession that was ignited by the rising cost of OPEC oil resulted in a steep drop in the demand for oil and a crash in oil’s price—to a low of approxi- mately $7 a barrel in the mid-1980’s.. $7.2 billion of the SFC’s initial $20 billion authoriza- tion. Most of the country’s oil, gas, and power needs...
tailieu.vn Xem trực tuyến Tải xuống
His- torically, the Pyrenees Mountains of France were a major source of talc and contributed to the beginning of the cosmetic’s industry in that country.. The talc is then shoveled out of the mine in order to be crushed. How- ever, high-grade talcs, such as those used in the phar- maceutical industry, require treatment with various chemical compounds.. In the...