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pyroclastic flow

(Encyclopedia)pyroclastic flow, turbulent, fluidized mixture of rock, volcanic ash, and hot gas that moves like an avalanche away from a volcanic eruption. A pyroclastic flow may contain a mix of rock fragments ran...

blackbuck

(Encyclopedia)blackbuck, small antelope, Antilope cervicapra, found in semidesert plains and open forest throughout India. Males are dark brown above and white below, with white rings around the eyes; they stand ab...

slipped disc

(Encyclopedia)slipped disc, rupture or herniation of an intervertebral disc. These discs separate and cushion the vertebrae, the segments of the spinal column. They are composed of an outer rim of fibrous connectiv...

Stoddart, James Fraser

(Encyclopedia)Stoddart, James Fraser, 1942–, British chemist, Ph.D. Univ. of Edinburgh, 1966. He began his career at Sheffield Univ., England, in 1970, then moved to Birmingham Univ., England, in 1990, the Univ. ...

chain reaction

(Encyclopedia)CE5 Chain reaction: A neutron (n) strikes the uranium nucleus (U-235), causing it to split into fission products A and B and release two neutrons. These neutrons can in turn cause further fissions....

copperhead

(Encyclopedia)copperhead, poisonous snake, Ancistrodon contortrix, of the E United States. Like its close relative, the water moccasin, the copperhead is a member of the pit viper family and detects its warm-bloode...

firebrick

(Encyclopedia)firebrick, brick that can withstand high temperatures, used to line flues, stacks, furnaces, and fireplaces. In general, such bricks have high melting points that range from about 2,800℉ (1.540℃) ...

incubator

(Encyclopedia)incubator, apparatus for the maintenance of controlled conditions in which eggs can be hatched artificially. Incubator houses with double walls of mud, a fireroom, and several compartments each holdin...

Mullis, Kary Banks

(Encyclopedia)Mullis, Kary Banks, 1944–2019, American biochemist, b. Lenoir, N.C., Ph.D. Univ. of California, Berkeley, 1972. Mullis was a researcher with Cetus Corp., Emeryville, Calif., from 1979 to 1986 and wi...

perfluoroalkyl and polyfluoroalkyl substances

(Encyclopedia)perfluoroalkyl and polyfluoroalkyl substances (PFAS), a group of several thousand synthetic organic chemical compounds made up of a chain of carbon atoms bonded to fluorine atoms. PFAS, which resist w...