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noise
(Encyclopedia)noise, any signal that does not convey useful information. Electrical noise consists of electrical currents or voltages that interfere with the operation of electronic systems. Electrical noise limits...mountain beaver
(Encyclopedia)mountain beaver, stout, short-limbed North American rodent, Aplodontia rufa, not closely related to the true beaver. Also called sewellel beaver after the Chinook word for a robe made from its pelts, ...function
(Encyclopedia)function, in mathematics, a relation f that assigns to each member x of some set X a corresponding member y of some set Y; y is said to be a function of x, usually denoted f(x) (read “f of x ”)....thermionic emission
(Encyclopedia)thermionic emission thûrmˌīŏnˈĭk [key], emission of electrons or ions by substances that are highly heated, the charged particles being called thermions. The number of thermions emitted increase...statistical mechanics
(Encyclopedia)statistical mechanics, quantitative study of systems consisting of a large number of interacting elements, such as the atoms or molecules of a solid, liquid, or gas, or the individual quanta of light ...irrigation
(Encyclopedia)irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e...tornado
(Encyclopedia)tornado, dark, funnel-shaped cloud containing violently rotating air that develops below a heavy cumulonimbus cloud mass and extends toward the earth. The funnel twists about, rises and falls, and whe...sertão
(Encyclopedia)sertão sərˈtouN [key] [Port.,=backlands], semiarid hinterland of NE Brazil; c.250,000 sq mi (647,500 sq km). Its characteristic landscape is the caatinga, or thorny scrub forest. The chief occupati...São Francisco
(Encyclopedia)São Francisco souN frəsēshˈko͝o [key], river, c.1,800 mi (2,900 km) long, rising in the Serra de Canastra, SW Minas Gerais state, Brazil, and flowing northeast, then southeast through the sertão...Pskov
(Encyclopedia)Pskov pəskôfˈ [key], city (1989 pop. 204,000), capital of Pskov region, NW European Russia, on the Velikaya River. It is an important rail junction in the heart of a flax-growing area. Industries i...Browse by Subject
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