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Braille, Louis

(Encyclopedia)Braille, Louis brāl, Fr. lwē brīˈyə [key], 1809?–1852, French inventor of the Braille system of printing and writing for the blind. Having become blind from an accident at the age of 3, he was ...

astronomical coordinate systems

(Encyclopedia)astronomical coordinate systems. A coordinate system is a method of indicating positions. Each coordinate is a quantity measured from some starting point along some line or curve, called a coordinate ...

Atlas Mountains

(Encyclopedia)Atlas Mountains, system of ranges and plateaus in NW Africa, extending c.1,500 mi (2,410 km) from SW Morocco, through N Algeria, to N Tunisia; Jebel Toubkal (13,671 ft/4,167 m), in SW Morocco, is the ...

Lancaster, Joseph

(Encyclopedia)Lancaster, Joseph, 1778–1838, English educator. In 1801 he founded a free elementary school, using a type of monitorial system for which he acknowledged his debt to Andrew Bell. The Royal Lancasteri...

corvée

(Encyclopedia)corvée kôrvāˈ [key], under the feudal system, compulsory, unpaid labor demanded by a lord or king and the system of such labor in general. There were national and local variations, but in broad te...

control systems

(Encyclopedia)control systems, combinations of components (electrical, mechanical, thermal, or hydraulic) that act together to maintain actual system performance close to a desired set of performance specifications...

exoplanet

(Encyclopedia)exoplanet or extrasolar planet, a planet located outside the solar system. See planet; planetary system. ...

standpipe

(Encyclopedia)standpipe, tank or pipe for holding water in an elevated position to create pressure in a water supply system. For a tall building, where the pressure from the mains at street level is insufficient to...

stimulant

(Encyclopedia)stimulant, any substance that causes an increase in activity in various parts of the nervous system or directly increases muscle activity. Cerebral, or psychic, stimulants act on the central nervous s...

Strategic Defense Initiative

(Encyclopedia)Strategic Defense Initiative (SDI), former U.S. government program responsible for research and development of a space-based system to defend the nation from attack by strategic ballistic missiles (se...