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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...

rapid transit

(Encyclopedia)rapid transit, transportation system designed to allow passenger travel within or throughout an urban area, usually employing surface, elevated, or underground railway systems or some combination of t...

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...

Fourcroy, Antoine François, comte de

(Encyclopedia)Fourcroy, Antoine François, comte de äNtwänˈ fräNswäˈ kôNt də fo͞orkrwäˈ [key], 1755–1809, French chemist. He was a pioneer in animal and plant chemistry and collaborated with Lavoisier ...

Hitchcock, Frank Harris

(Encyclopedia)Hitchcock, Frank Harris, 1867–1935, U.S. Postmaster General (1909–13), b. Amherst, Ohio. After service in the Dept. of Agriculture (1897–1903), the Dept. of Commerce and Labor (1903–5), and as...

free energy

(Encyclopedia)free energy or Gibbs free energy, quantity derived from the relationships between heat and work studied in thermodynamics and used as a measure of the relative stability of a physical or chemical syst...

Hulse, Russell Alan

(Encyclopedia)Hulse, Russell Alan, 1950–, American astrophysicist, b., New York City, Ph.D. Univ. of Massachusetts, Amherst, 1975. Hulse was a researcher at the Princeton's plasma physics laboratory from 1977 unt...

Saimaa

(Encyclopedia)Saimaa sīˈmä [key], lake system c.1,850 sq mi (4,790 sq km), occupying the heavily glaciated plateau of S central Finland. It comprises more than 120 connecting lakes; the large southern basin of t...

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...

hysteresis

(Encyclopedia)hysteresis hĭsˌtərēˈsĭs [key], phenomenon in which the response of a physical system to an external influence depends not only on the present magnitude of that influence but also on the previous...