Gary City (pop., 2000: 102,746), northwestern Indiana, U.S. Located at the southern end of Lake Michigan, it was laid out by the U.S. Steel Corp. in 1906. Gary prospered until a decline in the steel industry in the 1980s led to plant closings. City revitalization efforts were introduced in the 1990s. It was the scene, in the early 20th century, of a development in public education when William A. Wirt (b. 1874—d. 1938) established the work-study-play school, popularly known as the platoon school.
Gary, Elbert H(enry) (b. Oct. 8, 1846, near Wheaton, Ill., U.S.—d. Aug. 15, 1927, New York, N.Y.) U.S. businessman, chief organizer of the U.S. Steel Corp. He began practicing law in 1871, becoming an authority on corporate law, and he served as judge of DuPage County, Ill. (1882— 90). In 1898 he became president of Federal Steel Co.; when Federal merged with other companies to become U.S. Steel Corp. in 1901, Gary was elected chairman of the board of directors. As chief executive officer for 26 years, he presided over its growth and development. He promoted profit sharing, higher wages, and better working conditions, but he was a firm opponent of unions. Gary, Ind., named in his honour, was laid out in 1906 by U.S. Steel.
gas One of the three fundamental states of matter, in which matter has no definite shape, is very fluid, and has a density about 0.1% that of liq¬ uids. Gas is very compressible but tends to expand indefinitely, and it fills any container. A small change in temperature or pressure produces a sub¬ stantial change in its volume; these relationships are expressed as equa¬ tions in the gas laws. The kinetic theory of gases, developed in the 19th century, describes gases as assemblages of tiny particles (atoms or mol¬ ecules) in constant motion and contributed much to an understanding of their behaviour. The term gas can also mean gasoline, natural gas, or the anesthetic nitrous oxide. See also solid.
gas, intestinal See intestinal gas
gas chromatography (GC) Type of chromatography with a gas mix¬ ture as the mobile phase. In a packed column, the packing or solid sup¬ port (held in a tube) serves as the stationary phase (vapour-phase
William Lloyd Garrison.
LIBRARY OF CONGRESS, WASHINGTON, D.C.
Marcus Garvey, 1922.
UPI
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gas laws ► gastrectomy I 739
chromatography, or VPC) or is coated with a liquid stationary phase (gas- liquid chromatography, or GLC). In capillary columns, the stationary phase coats the walls of small-diameter tubes. The sample of gas or vola¬ tile liquid to be analyzed is injected into the inlet; its components move through with a carrier gas (usually hydrogen, helium, or argon) at rates influenced by their degree of interaction with the stationary phase. The temperature, nature of the stationary phase, and column length can be varied to improve separation. The gas stream issuing from the column’s end may pass through a thermal conductivity detector or a flame ioniza¬ tion detector, where its properties are compared with those of known ref¬ erence substances. GC is used to measure air pollutants, essential oils, gases or alcohol in blood, and composition of industrial process streams.
gas laws Laws that relate the pressure, volume, and temperature of a gas. Boyle’s law—named for Robert Boyle —states that, at constant tempera¬ ture, the pressure P of a gas varies inversely with its volume V, or PV = k, where k is a constant. Charles’s law—named for J.-A.-C. Charles (1746-1823)—states that, at constant pressure, the volume V of a gas is directly proportional to its absolute (Kelvin) temperature T, or V/T = k. These two laws can be combined to form a single generalization of the behaviour of gases known as an equation of state, PV = nRT, where n is the number of gram-moles of a gas and R is called the universal gas con¬ stant. Though this law describes the behaviour of an ideal gas, it closely approximates the behaviour of real gases. See also Joseph Gay-Lussac.
gas reservoir In geology, a naturally occurring storage area, charac¬ teristically a folded rock formation, that traps and holds natural gas. The reservoir rock must be permeable and porous to contain the gas, and it has to be capped by impervious rock in order to form an effective seal and prevent the gas from escaping. Typical reservoir rocks are sedimen¬ tary and include sands, sandstones, arkoses, and fissured limestones and dolomites. In the U.S. and certain other countries, artificial gas reservoirs are being created from depleted oil and gas fields, particularly near salt domes and in sedimentary basins, to store gas during periods of low con¬ sumption for later use.
Gascony \'gas-ks-ne\ French Gascogne \ga-'skon y \ ancient Vasco- nia Historical and cultural region, southwestern France. It encompasses portions of the southwestern French regions of Aquitaine and Midi- Pyrenees. Historically, it consisted of the northern foothills of the Pyrenees and extended east from the Basque Country along the France-Spain bor¬ der to Toulouse on the upper Garonne River. Under Roman rule it was the province of Novempopulana. Taken by the Visigoths in the 5th century and by the Franks in 507, it was overrun from 561 by the Basques, or Vascones; in 602 the Frankish kings recognized Vasconia, or Gascony, as a duchy. In 1052 it was conquered by Aquitaine, and in the 12th century it passed to the Plantagenet kings of England. In the Hundred Years' War, Gascony retained English allegiance until the French reconquest in the mid-15 th century.
Gascony, Gulf of See Bay of Bis¬ cay
Gascoyne River \'gas-,k6in\
River, western Western Australia. It rises west of the Gibson Desert and flows west for 475 mi (760 km) through gold-mining and sheep¬ raising country and empties into the Indian Ocean at Carnarvon on Shark Bay.
Gaskell Vgas-kolV, Elizabeth (Cleghorn) orig. Elizabeth Cleghorn Stevenson known as Mrs. Gaskell (b. Sept. 29, 1810,
Chelsea, London, Eng.—d. Nov. 12,
1865, near Alton, Hampshire) British writer. The daughter of a Unitarian minister, Gaskell also married a Uni¬ tarian minister and began writing in middle age. Cranford (1853), her most popular novel, and the unfin¬ ished Wives and Daughters (1864- 66), perhaps her best, are about the lives of country villagers. Mary Bar¬ ton (1848), Ruth (1853), and North
and South (1855) examine social problems of the urban working class. In 1857 she wrote the first biography of her friend Charlotte Bronte (see Bronte sisters).
gasoline British petrol Mixture of volatile, flammable hydrocarbons derived from petroleum, used as fuel for internal-combustion engines and as a solvent for oils and fats. Gasoline became the preferred automobile fuel because it releases a great deal of energy when burned, it mixed readily with air in a carburetor, and it initially was cheap due to a large supply. Costs have now increased greatly except where subsidized. Gasoline was first produced by distillation. Later processes increased the yield from crude oil by splitting large molecules into smaller ones. Still other meth¬ ods, such as conversion of straight-chain hydrocarbons into their branched-chain isomers, followed. The resulting gasoline is a complex mixture of hundreds of hydrocarbons. A gasoline’s octane number indi¬ cates its ability to resist knocking (premature combustion) and can be altered by changing the proportions of certain components. The compound tetraethyl lead, once used to reduce knocking, has been banned as toxic. Other additives include detergents, antifreezes, and antioxidants. Since the mid-20th century gasoline fumes have been recognized as a major com¬ ponent of urban air pollution. Efforts to reduce dependence on gasoline, which is a nonrenewable resource, include use of gasohol, a 9:1 mix of gasoline and ethanol, and the development of electric automobiles.
gasoline engine Most widely used form of internal-combustion engine, found in most automobiles and many other vehicles. Gasoline engines vary significantly in size, weight per unit of power generated, and arrangement of components. The principal type is the reciprocating-piston engine. In four-stroke engines, each cycle requires four strokes of the piston—intake, compression, power (expansion), and exhaust—and two revolutions of the crankshaft. In a two-stroke cycle, the compression and power strokes of the four-stroke cycle are carried out without the inlet and exhaust strokes, in one upstroke and one downstroke of the piston and one revolution of the crankshaft. The size, weight, and cost of the engine per horsepower are therefore less, and two-stroke-cycle engines are used in motorcycles and smaller machines (e.g., lawnmowers and power rakes). See also com¬ pression RATIO, PISTON AND CYLINDER, ROTARY ENGINE.