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asphalt
(Encyclopedia)asphalt ăsˈfôlt, –fălt [key], brownish-black substance used commonly in road making, roofing, and waterproofing. Chemically, it is a natural mixture of hydrocarbons. It varies in consistency fro...Sudd
(Encyclopedia)Sudd so͝od [key], swampy region, c.200 mi (320 km) long, and c.150 mi (240 km) wide, central South Sudan, E central Africa. It is fed by the Bahr el Jebel, the Bahr el Ghazal, and the Bahr el Arab, h...shellac
(Encyclopedia)shellac, solution of lac in alcohol or acetone. In commerce the name is applied to the resinous substance (lac) itself rather than to the solution. It ranges in color from orange to light yellow depen...catchment area
(Encyclopedia)catchment area or drainage basin, area drained by a stream or other body of water. The limits of a given catchment area are the heights of land—often called drainage divides, or watersheds—separat...humidity
(Encyclopedia)humidity, moisture content of the atmosphere, a primary element of climate. Humidity measurements include absolute humidity, the mass of water vapor per unit volume of natural air; relative humidity (...sodium sulfate
(Encyclopedia)sodium sulfate, chemical compound, Na2SO4. It is a white, orthorhombic crystalline compound at ordinary temperatures; above 100℃ it assumes a monoclinic structure, and above about 250℃ it assumes ...Dubochet, Jacques
(Encyclopedia)Dubochet, Jacques, 1942–, Swiss biophysicist and molecular biologist, Ph.D., Univ. of Geneva 1973. Dubochet was a researcher at the European Molecular Biology Laboratory in Heidelberg from 1978 to 1...chernozem
(Encyclopedia)chernozem chĕrˈnəzĕmˌ [key] or black earth, variety of soil rich in organic matter in the form of humus. It is generally a modified type of loess. True chernozem is black in color, but there are ...precipitation, in chemistry
(Encyclopedia)precipitation, in chemistry, a process in which a solid is separated from a suspension, sol, or solution. In a suspension such as sand in water the solid spontaneously precipitates (settles out) on st...Cannizzaro, Stanislao
(Encyclopedia)Cannizzaro, Stanislao stänēsläˈō kän-nēt-tsäˈrō [key], 1826–1910, Italian chemist. From 1861 he was professor at Palermo and from 1871 at Rome, where he was also a member of the senate and...Browse by Subject
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