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Winfrey, Oprah

(Encyclopedia)Winfrey, Oprah, 1954–, African-American television host, actress, and media magnate, b. Kosciusko, Miss., as Orpah Gail Winfrey, grad. Tennessee State Univ. (1976). She began her career as a Nashvil...

xenon

(Encyclopedia)xenon zēˈnŏn [key] [Gr.,=strange], gaseous chemical element; symbol Xe; at. no. 54; at. wt. 131.293; m.p. −111.9℃; b.p. −107.1℃; density 5.86 grams per liter at STP; valence usually 0. Xeno...

gear

(Encyclopedia)CE5 Types of gears gear, toothed wheel, cylinder, or cone that transmits motion from one part of a machine to another; it is one of the oldest means of transmitting motion. When the teeth of two g...

crank

(Encyclopedia)crank, mechanical linkage consisting of a bar attached to a pivot at one of its ends in such a way that it is capable of rotating through a complete circle about the pivot. One of the principal uses o...

Warner Brothers

(Encyclopedia)Warner Brothers, American movie studio executives and producers. Sons of poor E European Jewish immigrants, the brothers were Harry Morris (1881–1958), Albert (1884–1967), Samuel Louis (1887–192...

sonic boom

(Encyclopedia)CE5 Sonic boom wave pattern from a supersonic aircraft and variation in pressure sonic boom, shock wave produced by an object moving through the air at supersonic speed, i.e., faster than the spee...

audiovisual education

(Encyclopedia)audiovisual education, educational instruction by means of materials that use the senses of sight and hearing to stimulate and enrich learning experiences. The successful use of motion pictures and ot...

Strand, Paul

(Encyclopedia)Strand, Paul, 1890–1976, American photographer, b. New York City. Strand studied under Lewis Hine, who introduced him to Alfred Stieglitz. At Stieglitz's famed “291” gallery, Strand had his firs...

silver chloride

(Encyclopedia)silver chloride, chemical compound, AgCl, a white cubic crystalline solid. It is nearly insoluble in water but is soluble in a water solution of ammonia, potassium cyanide, or sodium thiosulfate (“h...

echo sounder

(Encyclopedia)echo sounder, an older instrumentation system for indirectly determining ocean floor depth. Echo sounding is based on the principle that water is an excellent medium for the transmission of sound wave...