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moment

(Encyclopedia)moment, in physics and engineering, term designating the product of a quantity and a distance (or some power of the distance) to some point associated with that quantity. The most theoretically useful...

Kitt Peak National Observatory

(Encyclopedia)Kitt Peak National Observatory, astronomical observatory located southwest of Tucson, Ariz.; it was founded in 1958 under contract with the National Science Foundation and is administered by the Assoc...

cathode-ray tube

(Encyclopedia)CE5 Cathode-ray tube cathode-ray tube (CRT), special-purpose electron tube in which electrons are accelerated by high-voltage anodes, formed into a beam by focusing electrodes, and projected towar...

refining

(Encyclopedia)refining, any of various processes for separating impurities from crude or semifinished materials. It includes the finer processes of metallurgy, the fractional distillation of petroleum into its comm...

continental drift

(Encyclopedia)CE5 Continental drift (arrows indicate the directions of motion of the landmasses) A. Proposed reconstruction of the supercontinent Pangaea indicating the major present landmasses B. Proposed recon...

Humboldt, Alexander, Freiherr von

(Encyclopedia)Humboldt, Alexander, Freiherr von hŭmˈbōlt, Ger. älĕksänˈdər frīˈhĕr fən ho͝omˈbôlt [key], 1769–1859, German naturalist, inventor, explorer, and author, the most eminent scientist of ...

computer

(Encyclopedia)CE5 Schematic diagram of a computer system: Data flow is indicated by solid lines; control signals are indicated by dashed lines. computer, device capable of performing a series of arithmetic or l...

analog-to-digital conversion

(Encyclopedia)analog-to-digital or A/D conversion, the process of changing continuously varying data, such as voltage, current, or shaft rotation, into discrete digital quantities that represent the magnitude of th...

Mawson, Sir Douglas

(Encyclopedia)Mawson, Sir Douglas, 1882–1958, Australian antarctic explorer and geologist, b. England. His first geographical expedition was to the New Hebrides Islands as a geologist in 1903. As a member of the ...

Lorentz, Hendrik Antoon

(Encyclopedia)Lorentz, Hendrik Antoon hĕnˈdrək änˈtōn lōˈrĕnts [key], 1853–1928, Dutch physicist, a pioneer in formulating the relations between electricity, magnetism, and light. He was one of the first...