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geodesy

(Encyclopedia)geodesy jēŏdˈĭsē [key] or geodetic surveying, theory and practice of determining the position of points on the earth's surface and the dimensions of areas so large that the curvature of the earth...

glycol

(Encyclopedia)glycol glīˈkōl [key], dihydric alcohol in which the two hydroxyl groups are bonded to different carbon atoms; the general formula for a glycol is (CH2)n(OH)2. The most important glycol is the simpl...

facsimile

(Encyclopedia)facsimile făksĭmˈəlē [key] or fax, in communications, system for transmitting pictures or other graphic matter by wire or radio. Facsimile is used to transmit such materials as documents, telegra...

feedback

(Encyclopedia)CE5 Basic feedback control system feedback, arrangement for the automatic self-regulation of an electrical, mechanical, or biological system by returning part of its output as input. A simple exam...

transformer

(Encyclopedia)transformer, electrical device used to transfer an alternating current or voltage from one electric circuit to another by means of electromagnetic induction. The simplest type of transformer consists ...

vampire bat

(Encyclopedia)vampire bat, name for the blood-drinking bats of the family Desmodontidae, found in the New World tropics. Vampire bats feed exclusively on the blood of living animals and are thus the only true paras...

radio range

(Encyclopedia)radio range, geographically fixed radio transmitter that radiates coded signals in all directions to enable aircraft and ships to determine their bearings. An aircraft or ship can determine its line o...

Henry, Pierre Georges

(Encyclopedia)Henry, Pierre Georges, 1927–2017, French composer noted for his contributions to electronic music. He studied with Nadia Boulanger and Olivier Messiaen at the Paris Conservatory, where he met Pierre...

instrument-landing system

(Encyclopedia)CE5 Instrument-landing system (ILS), the most common instrument-landing approach system, uses two beams to guide an airplane. instrument-landing system (ILS), ground-based radio system designed to...

emphysema

(Encyclopedia)emphysema ĕmfĭsēˈmə [key], pathological or physiological enlargement or overdistention of the air sacs of the lungs. A major cause of pulmonary insufficiency in chronic cigarette smokers, emphyse...