die Tool or device for imparting a desired shape, form, or finish to a material. Examples include a perforated block through which metal or plastic is drawn or extruded, the hardened steel forms for producing the patterns on coins and medals by pressure, and the hollow molds into which metal or plastic is forced. Modern tools and dies can be traced to the work of Honore Blanc at the Saint-Etienne armoury in France beginning in 1780. Blanc’s techniques were adopted and enlarged in the LJ.S. by Eli Whitney and others, who used templates (tool-guiding patterns) and fixtures—the antecedents of today’s tools and dies—to mass-produce fire¬ arms for the U.S. Army (see armoury practice). Today the demand for dies used in metal forming, die casting, and plastic molding is filled by tool- and die-making shops.
Die Brucke See Die Briicke
die casting Forming metal objects by injecting molten metal under pressure into dies or molds. An early and important use of the technique was in the Linotype machine (1884), but the mass-production automobile assembly line gave die casting its real impetus. Great precision is pos¬ sible, and products range from tiny parts for sewing machines and auto¬ mobiles to aluminum engine-block castings.
die making See tool and die making
Diebenkorn Vde-bon-.kornX, Richard (b. April 22, 1922, Portland, Ore., U.S.—d. March 30, 1993, Berkeley, Calif.) U.S. painter. After study¬ ing at Stanford University, he taught at California Institute of the Arts (1947-50), and there developed an abstract style under the influence of such painters as Clyfford Still and Mark Rothko. By the mid 1950s he had achieved some commercial success but turned to an expressionistic figu¬ rative style. He produced accomplished figure drawings, still lifes, land¬ scapes, and interiors in the Modernist tradition. Throughout his career he alternated between figuration and abstraction. His best-known works are the Ocean Park series, begun in the 1960s, comprising over 140 large abstract paintings that retain allusions to landscape.
Diefenbaker Vde-fon-.ba-korV John G(eorge) (b. Sept. 18, 1895, Grey county, Ont., Can.—d. Aug. 16, 1979, Ottawa) Prime minister of Canada (1957-63). After serving in World War I, he practiced law in Saskatchewan. He was elected to the Canadian House of Commons in 1940. He became leader of the Progressive Conservative Party in 1956 and served as prime minister from 1957 to 1963, when his party lost its majority in the House of Commons. He resigned as party leader in 1967. He was chancellor of the University of Saskatchewan from 1969 until his death.
dielectric \,dl-i-'lek-trik\ Insulating material or a very poor conductor of electric current. Dielectrics have no loosely bound electrons, and so no current flows through them. When they are placed in an electric field, the positive and negative charges within the dielectric are displaced minutely in opposite directions, which reduces the electric field within the dielec¬ tric. Examples of dielectrics include glass, plastics, and ceramics.
Diemen Vde-monV, Anthony van (b. 1593, Culemborg, Neth.—d. April 19, 1645, Batavia, Dutch East Indies) Dutch colonial administrator who consolidated the Dutch empire in the Far East. He joined the Dutch East India Company and served in Batavia from 1618. As governor-general of the Dutch East Indian settlements (1636-45), he enabled the Dutch to gain a monopoly of the spice trade in the Moluccas, conquer cinnamon-
producing areas in Ceylon (Sri Lanka), seize the key Portuguese strong¬ hold of Malacca, and capture all of Formosa (Taiwan). By 1645 he had established the United Provinces of The Netherlands as the paramount commercial and political power in the East Indies. Van Diemen also ini¬ tiated the exploring expeditions of Abel Janszoon Tasman and Frans Viss- cher (1642, 1644).
Dien Bien Phu Ydyen-'byen-'fiA, Battle of (1953-54) Decisive engagement in the first of the Indochina wars (1946-54) that marked the end of French involvement in Southeast Asia. The French fought the Viet Minh (Lien Viet) for control of a small mountain outpost near Laos. The French occupied the outpost, but the Vietnamese cut all the roads into it, leaving the French to rely on air supplies. Gen. Vo Nguyen Giap then attacked the base with heavy artillery and a force of 40,000 men; the base fell to him despite heavy U.S. aid to the French.
Dieppe Vdyep, de-'ep\ Town (pop., 1999: 34,598) and seaport, northern France, on the English Channel. French kings, realizing its strategic impor¬ tance, granted it numerous privileges. In 1668 almost 10,000 of its people died during a plague, and in 1694 the town was almost completely destroyed by English and Dutch fleets. In World War II it was the site of an unsuccessful Allied commando landing (1942). Its port is one of the safest on the Channel, but its shallowness hinders modern shipping.
Dies \'dlz\, Martin, Jr. (b. Nov. 5, 1901, Colorado, Texas, U.S.—d. Nov. 14, 1972, Lufkin, Texas) U.S. politician. He received a law degree from National University in Washington, D.C. in 1920. After practicing law in Texas, he won a seat in the U.S. House of Representatives (1931— 45, 1953-59). Though originally a supporter of the New Deal, by 1937 he had turned against it. In 1938 he was named chairman of the newly cre¬ ated House Un-American Activities Committee; popularly known as the Dies Committee, it pursued alleged communist subversives in New Deal agen¬ cies and labour unions. Wheareas conservatives applauded the exposure of supposedly disloyal government and union officials, liberals accused Dies of smearing reputations with unproved charges.
Diesel, Rudolf Christian Karl (b. March 18, 1858, Paris, France—d. Sept. 29, 1913, at sea in the English Channel) German thermal engineer. In the 1890s he invented the internal-combustion engine that bears his name, producing a series of increasingly successful models of the diesel engine that culminated in his demonstration in 1897 of a 25-horsepower, four-stroke, single vertical cylinder compression engine.
diesel engine Internal-combustion engine in which air is compressed to a temperature sufficiently high to ignite fuel injected into the cylinder, where combustion and expansion activate a piston (see piston and cylin¬ der). It converts the chemical energy stored in the fuel into mechanical energy, which can be used to power large trucks, locomotives, ships, small electric-power generators, and some automobiles. The diesel engine dif¬ fers from other internal-combustion engines (such as gasoline engines) in that it has no ignition system and so is often called a compression-ignition engine. Diesel fuel is low-grade and comparatively unrefined. Compared to other internal-combustion engines, diesel engines are more reliable, last longer, and cost less to operate, but they also produce more air pollution, noise, and vibration.
Diet Japanese national legislature. Under the Meiji Constitution, the Diet had two houses, a House of Peers and a House of Representatives, with equal powers. The Diet’s role was largely negative: it could block legis¬ lation and veto budgets. It was reconstituted under the U.S.-sponsored constitution of 1947. The (upper) House of Councillors seats 247 mem¬ bers, and the (lower) House of Representatives has 480 members. The prime minister, who leads the majority party in the lower house, must be a member. The House of Representatives can override the House of Coun¬ cillors on most issues.
Diet of Worms See Diet of Worms dietary fibre See dietary fibre
dieting Regulating food intake to improve physical condition, especially to lose weight. Examples include diets low in fat for weight loss, low in saturated fat and cholesterol to prevent or help treat coronary heart dis¬ ease, or high in carbohydrates and protein to build muscle. Weight-loss diets are based on reducing calorie intake in different proportions of fat, car¬ bohydrate, or protein; most result in some weight loss, but often the weight is gained back within a few years. Diets must include adequate
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