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dimension, in physics

(Encyclopedia)dimension, in physics, an expression of the character of a derived quantity in relation to fundamental quantities, without regard for its numerical value. In any system of measurement, such as the met...

Strauss, Lewis Lichtenstein

(Encyclopedia)Strauss, Lewis Lichtenstein strôz [key], 1896–1974, American financier, chairman of the Atomic Energy Commission (1953–58), b. Charleston, W.Va. In World War I he served under Herbert Hoover on t...

spring, in mechanics

(Encyclopedia)spring, in mechanics, any of several elastic devices used variously to store and to furnish energy, to absorb shock, to sustain the pressure between contacting surfaces, and to resist tensional or com...

Richland

(Encyclopedia)Richland, city (1990 pop. 32,315), Benton co., S Wash., at the confluence of the Columbia and Yakima rivers, in an irrigated farm and vineyard region; inc. 1958. It is the headquarters of the U.S. Dep...

fuel cell

(Encyclopedia)fuel cell, electric cell in which the chemical energy from the oxidation of a gas fuel is converted directly to electrical energy in a continuous process (see oxidation and reduction). The efficiency ...

photochemistry

(Encyclopedia)photochemistry, study of chemical processes that are accompanied by or catalyzed by the emission or absorption of visible light or ultraviolet radiation. A molecule in its ground (unexcited) state can...

superfluidity

(Encyclopedia)superfluidity, tendency of liquid helium below a temperature of 2.19K to flow freely, even upward, with little apparent friction. Helium becomes a liquid when it is cooled to 4.2K. Special methods...

machine

(Encyclopedia)machine, arrangement of moving and stationary mechanical parts used to perform some useful work or to provide transportation. From a historical perspective, many of the first machines were the result ...

planet

(Encyclopedia)planet [Gr.,=wanderer], a large nonluminous body of rock, gas, or ice that orbits the sun or another star, has a rounded shape due to gravity, and has cleared its orbit of smaller objects. The term, o...

North Dakota, University of

(Encyclopedia)North Dakota, University of, at Grand Forks; state supported; coeducational; chartered 1883, opened 1884. It has several professional schools, including those for aerospace sciences, engineering and m...