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phosphoric acid

(Encyclopedia)phosphoric acid, any one of three chemical compounds made up of phosphorus, oxygen, and hydrogen (see acids and bases). The most common, orthophosphoric acid, H3PO4, is usually simply called phosphori...

hydrazine

(Encyclopedia)hydrazine hīˈdrəzēnˌ [key], chemical compound, formula NH2NH2, m.p. 1.4℃, b.p. 113.5℃, specific gravity 1.011 at 15℃. It is very soluble in water and soluble in alcohol. At ordinary tempera...

Ryan, Kay

(Encyclopedia)Ryan, Kay, 1945–, American poet, b. San Jose, Calif., grad. Univ. of California at Los Angeles (B.A., 1967; M.A., 1968). She taught remedial English in a Marin co. community college for more than 30...

Enceladus

(Encyclopedia)Enceladus ĕnsĕlˈədəs [key], in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn II (or S2), Enceladus is 310 mi (500 km) in diameter, orbits Saturn at a m...

aqueduct

(Encyclopedia)aqueduct ăkˈwədŭkt [key] [Lat.,=conveyor of water], channel or trough built to convey water, chiefly for providing a densely populated region with a supply of freshwater. The flow in aqueducts is ...

ballistics

(Encyclopedia)ballistics bəlĭsˈtĭks [key], science of projectiles. Interior ballistics deals with the propulsion and the motion of a projectile within a gun or firing device. Its problems include the ignition a...

mass, in physics

(Encyclopedia)mass, in physics, the quantity of matter in a body regardless of its volume or of any forces acting on it. The term should not be confused with weight, which is the measure of the force of gravity (se...

urinalysis

(Encyclopedia)urinalysis yo͝orˌənălˈĭsĭs [key], clinical examination of urine for the purpose of medical diagnosis. Urine is initially examined for such characteristics as color, odor, and specific gravity. ...

Penrose, Sir Roger

(Encyclopedia)Penrose, Sir Roger, 1931–, British mathematical physicist, Ph.D. Cambridge, 1958. He taught and conducted research at a number of British and American colleges and universities before becoming a pro...

centering

(Encyclopedia)centering, the framework of wood or of wood and steel built to support a masonry arch or vault during its construction. The centering itself must be rigidly supported, either by posts from the ground ...