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These fractures may be microscopic or may be vis- ible to the naked eye. Most of the world’s perlite is found in the western half of the United States. New Mexico supplies about three-quarters of the nation’s perlite. By the 1970’s, it was a common product used in the horticultural industry.. It is then crushed to the desired particle size...
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Petroleum refining and processing. Petroleum is first distilled, then each of the “cuts” is further treated or blended to pro- vide the various marketed products. Petroleum, or crude oil, is found in many parts of the world. Rather, petroleum is a complex mix- ture of hundreds of individual chemical compounds that occur in various proportions, depending on the source and...
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Forest Service, Pinchot became active in the Progressive Party, founded by supporters of Theo- dore Roosevelt. Placer deposits. Gold is soft and malleable but is otherwise nearly inert in the weathering realm. Hence, once gold is weathered out of the lode deposits where it ini- tially formed, the grains may survive transport in streams and rivers over long distances. It...
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The theory of plate tectonics provides an explanation for the present-day structure of the outer part of the Earth. Plate tectonic theory is based on a concept of the Earth in which a rigid, outer shell, the lithosphere, lies above a hotter, weaker, partially molten part of the mantle known as the asthenosphere. The thickness of the lithosphere varies between...
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gling small amounts of high-grade plutonium and uranium for sale in the West. After the terrorist attacks in the United States on September 11, 2001, fears of terrorists acquiring and using nuclear weapons were heightened. Plutonium: A History of the World’s Most Danger- ous Element. “The Actinide and Transactinide Elements.” In Chemistry of the Ele- ments. Controlling the Atom in...
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Producers of Portuguese olive oil who use the “protected denomination of ori- gin” label must use only olives from certain areas and follow a strict set of rules about the production of the oils. It produces about 9 percent of the tomatoes grown worldwide, with an average of about 864,000 metric tons per year, making it the eighth largest producer...
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Commercially, the clean-burning fuel is main- tained in the liquid state, which is obtained under conditions of elevated pressures, in a steel container.. As a result butane tends to be used in the south- ern United States, while propane (which condenses at −42° Celsius under normal pressure conditions is used in the North.. Modern Pe- troleum: A Basic Primer of...
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quartz crystals have been mined in Brazil, and smaller crystals are found in the United States—for example, in Arkansas and New York State (the “Herkimer dia- mond” deposits). Sec- ondary uses are found in the gemstone industry.. A striking example of quartz is the gradual petrifica- tion of trees, which occurs as the silica redeposits in the wood. Grasses such...
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These issues have become controversial in the United States.. and many ro- dents and insects), carnivores and omnivores (coy- otes, bears, weasels, eagles, spiders, and cougars), and decomposers that break down organic matter into el- ements that can be utilized by plants. Plants convert carbon dioxide and water into complex carbohydrates, fats, and proteins that can be utilized by animals...
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ing seismic studies to decode the in- terior of the Earth. Remote sensing developed from several origins, both scientific and technological. Technologically, the telescope, invented in the 1600’s, and photography, invented in the 1840’s, were significant advances in our abil- ity to remotely sense our environ- ment. Then, the discovery of energy (frequencies) beyond the familiar vis- ible light, in...
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Subtitle J, established in 1988 with the enactment of the MWTA, was a limited-duration demonstration project for tracking medical waste and regulating medical-waste handlers. facilities producing phosphoric acid and phosphate compounds were of particular concern because of the environmental threat posed by these chemicals. By making the mineral processing and mining sectors a nationwide priority, the EPA sought to protect...
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RFF researchers have been influential members of the Intergovernmental Panel on Climate Change (IPCC) and have helped in the formulation of U.S. Resources for the Future. Rhenium is widely distributed in the Earth’s crust in small amounts. In the United States, the richest con- centrations of rhenium are found in molybdenum ores in Arizona, Utah, and New Mexico. Rhenium (abbreviated...
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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...
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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...
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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...
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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...
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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...
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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...
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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....
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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...