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calendering

(Encyclopedia)calendering, a finishing process by which paper, plastics, rubber, or textiles are pressed into sheets and smoothed, glazed, polished, or given a moiré or embossed surface. The material is passed thr...

corona, in astronomy

(Encyclopedia)corona, luminous envelope surrounding the sun, outside the chromosphere. Its density is less than one billionth that of the earth's atmosphere. The corona is visible only at the time of totality durin...

oxyacetylene torch

(Encyclopedia)oxyacetylene torch ŏkˌsēəsĕtˈəlēn [key], tool that mixes and burns oxygen and acetylene to produce an extremely hot flame. This torch can be used for cutting steel and for welding iron and var...

bubble chamber

(Encyclopedia)bubble chamber, device for detecting charged particles and other radiation by means of tracks of bubbles left in a chamber filled with liquid hydrogen or other liquefied gas. It was invented in 1952 b...

blizzard

(Encyclopedia)blizzard, winter storm characterized by high winds, low temperatures, and driving snow; according to the official definition given in 1958 by the U.S. Weather Bureau, the winds must exceed 35 mi (56 k...

echo, in acoustics

(Encyclopedia)echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...

Gulf Stream

(Encyclopedia)Gulf Stream, warm ocean current of the N Atlantic Ocean, off E North America. It was first described (1513) by Spanish explorer Ponce de León. The Gulf Stream originates in the Gulf of Mexico and, as...

phosphorescence

(Encyclopedia)phosphorescence fŏsˌfərĕsˈəns [key], luminescence produced by certain substances after absorbing radiant energy or other types of energy. Phosphorescence is distinguished from fluorescence in th...

Brownian movement

(Encyclopedia)Brownian movement or motion, zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid. The effect has been observed in all types of colloidal suspensions (see colloid...

McLennan, Sir John Cunningham

(Encyclopedia)McLennan, Sir John Cunningham, 1867–1935, Canadian physicist, grad. Univ. of Toronto (B.A., 1892; Ph.D., 1900). He taught at the Univ. of Toronto from 1892 to 1932, was professor of physics from 190...