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acetate

(Encyclopedia)acetate ăsˈĭtātˌ [key], one of the most important forms of artificial cellulose-based fibers; the ester of acetic acid. The first patents for the production of fibers from cellulose acetate appea...

direction finder

(Encyclopedia)direction finder, electronic device used to determine the position of a ship or aircraft. In a simple direction finder a radio receiver is equipped with a revolving directional antenna. The antenna re...

expert system

(Encyclopedia)expert system, a computer system or program that uses artificial intelligence techniques to solve problems that ordinarily require a knowledgeable human. The method used to construct such systems, kno...

Pedersen, Charles John

(Encyclopedia)Pedersen, Charles John, 1904–89, American chemist, b. Busan, Korea, M.S. Massachusetts Institute of Technology, 1927. After finishing his studies, Pedersen began work as a research chemist for the D...

Roanne

(Encyclopedia)Roanne rôänˈ [key], town (1990 pop. 42,848), Loire dept., E central France, on the Loire River. Cotton and metals are the chief products; other industries include tanning, machine and vehicle manuf...

Fort Peck Dam

(Encyclopedia)Fort Peck Dam, 21,430 ft (6,531 m) long and 250 ft (76 m) high, on the Missouri River, NE Mont.; one of the world's largest earth-filled dams. The dam was built (1933–40) by the U.S. Army Corps of E...

Pointe-Noire

(Encyclopedia)Pointe-Noire pwăNt-nwär [key], city (1984 pop. 294,203), SW Republic of the Congo, Africa, a port on the Atlantic Ocean. Offshore oil drilling and oil refining are the city's most important economic...

Port Charlotte

(Encyclopedia)Port Charlotte, uninc. town (1990 pop. 41,535), Charlotte co., SW Fla., on Charlotte Harbor (an inlet of the Gulf of Mexico) and the Peace and Myakka rivers. It is a planned residential community—on...

pyroxylin

(Encyclopedia)pyroxylin pīrŏkˈsĭlĭn [key], partially nitrated cellulose (see nitrocellulose). It is used in lacquers, plastics, and artificial leathers. Pyroxylin lacquers are made by dissolving pyroxylin in a...

oasis

(Encyclopedia)oasis ōāˈsĭs [key], an area within a desert where the water table reaches the surface, with enough moisture to permit the growth of vegetation. The water may come up to the surface in springs, or ...