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`

`
`
`On the cover: Pattern produced from white light by a computer-generated
`diffraction plate containing 529 square apertures arranged in a 23 x 23 array.
`(R. B. Hoover, Marshall Space Flight Center)
`
`On the title pages: Aerial photograph of the Sinai Peninsula made by Gemini
`spacecraft. (NASA)
`
`Included in this Dictionary are definitions which have been published previously in the following
`works: P. B. Jordain, Condensed Computer Encyclopedia, Copyright © 1969 by McGraw—Hill, Inc.
`All rights reserved. I. Markus, Electronics and Nucleoriics Dictionary, 4th ed., Copyright © 1960,
`1966, 1978 by l‘v’IcCraw—l'lill, Inc. All rights reserved. J. Quick, Artists” and Illustrators" Encyclopedia,
`Copyright © 1969 by McCraw-Hill, Inc. All rights reserved. Blakiston’s Gould Medical Dictionary,
`3d ed., Copyright © 1956, 1972 by MoGraw—Hill, Inc. All rights reserved. T. Baumeister and
`L. 5. Marks, eds. Standard Handbookfiir Mechanical Engineers, 7th ed., Copyright © .1958, 1967
`by McGraw-Ilill, Inc. All rights reserved.
`
`lluschke, Glossary of
`In addition, material has been drawn from the following references: R. E.
`J’l’Ieteorology, American ll'leteorological Society, 1959; U.S. Air Force Glossary of Standardized Terms,
`AI“ Manual 11—1, Vol.
`I, 1972; ComrnaniccitiorLS~ElectrOItics Terminology, AI“ Manual 11—1, vol. 3,
`1970; W, H. Allen, ed., Dictionary of Technical Terms for Aerospace Use,
`lst ed., National Aero-
`nautics and Space. Administration, 1965; J. M. Gilliland, Solar—Terrestrial Physics: A Glossary of
`Terms and Abbreviations, Royal Aircraft Establishment Technical Report 67158,
`.1967; Glossary of
`Air Traffic Control Terms, Federal Aviation Agency; A Glossary ofRange Terminology, White Sands
`Missile Range, New Mexico, National Bureau of Standards, AD 4-67-1124; A DOD Glossary ofMapping,
`Charting and Geodetic Terms. lst ed., Department of Defense, 1967; P. W. Thrush, comp. and ed.,
`A Dictionary of Mining, Mineral, and Related Terms, Bureau of Mines, 1968; Nuclear Terms: A
`Glossa
`, 2d ed., Atomic Energy Commission; I“. Casey, ed., Compilation of Terms in Information
`deral Council for Science and Technology, 1970; Glossary of Sim/2; Ternti—~
`iace Research, [1.5. Air l’orce, 1963: Naval Dictionary ofElec-tronic, Tech—
`Terms, Bureau of Naval Personnel, 1962; ADP Glossary, Department of the
`
`
`
`
` McGR HILL DICTIONARY 0F SCIENTIFIC AND TECHNICAL TERMS,
`
`Fourth Edition
`
`l978, 1976, 197/1: by lV’IcCraw—Hill, Inc. All rights reserved. Printed in
`Copyright © 1989, I984,
`the United States of America. Except as permitted under the United States Copyright Act of 1976,
`no part of this publication may be reproduced or distributed in any form or by any means, or stored
`in a data base or retrieval system. without the prior written permission of the publisher.
`
`12344567890
`
`DOW/DOW
`
`8954321098
`
`ISBN D—U?~UHSE?D-‘l
`
`Library of Congress Cataloging-in-Publication Data
`
`McGraw—l‘lill dictionary of scientific: and technical terms.
`
`I. Science—Dictionaries
`1. Parker. Sybil P.
`1989
`(2123.1“34
`ISBN 0-07-045270—9
`
`2. Technology-Dietionaries
`
`503721
`
`88« 134190
`
`For more information about other McGraw-Hill materials, call 1-800-2-MCGRAW in the
`United States. ln other countries, call your nearest McGraw—Hill office.
`
`
`
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`
`referee/tamt/m
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`

`

`860 '" Hartmann dispersion formula
`
`[OPTICS] A semiempirical
`Hartmann dispersion formula
`formula relating the index of refraction n and wavelengths A;
`n = no + a/(A — A0), where no, a, and A0 are empirical
`constants. Also known as Comu-Hartmann formula.
`{ ‘hart-
`man di'sper'zhon ,fOr-mye-lo }
`Hartmann flow [PL PHYS] The steady flow of an electrically
`conducting fluid between two parallel plates when there is a
`uniform applied magnetic field normal to the plates.
`{ 'har’t-
`man ,flo }
`{ 'hart‘man Ilinz }
`Hartmann lines See Liiders lines.
`A dimensionless number
`Hartmann number
`[PL PHYS]
`which gives a measure of the relative importance of drag forces
`resulting from magnetic induction and viscous forces in Hart-
`mann flow, and determines the velocity profile for such flow.
`{ 'hart'man ,nom-bor }
`Hartmann test
`[oancs] Atestfortelescopemirrorsinwhich
`the mirror is covered with a screen with regularly spaced holes,
`and a photographic plate is placed near the focus; for a perfect
`mirror,
`this results in regularly spaced dots on the plate.
`[SPECT] A test for spectrometers in which light is passed
`through different parts of the entrance slit; any resulting changes
`of th: spectrum indicate a fault in the instrument.
`{ 'hart‘man
`,test
`Hartman’s solution
`[ANALY CHEM]
`Solution of thymol,
`ethyl alcohol, and sulfuric ether; used for selective dentin anal—
`ysis.
`{ 'hart-msnz so,lii-shan’}
`Hart-Park Virus
`[VlROL] A ribonucleic acid—containing an—
`imal virus of the rhabdovirus group.
`{ 'hart 'park ,vi-ros }
`hartree
`[ATOM PHYS] A unit of energy used in studies of
`atomic spectra and structure, equal (in centimeter—gram-second
`units) to 4n2me4/h2, where e and m are the charge and 'mass of
`the electron, and h is Planck’s constant; equal to approximately
`27.2l electronvolts or 4.360 X 10‘18joule.
`{ ‘har-tre }
`Hartree equation
`[ELECTR] An equation which gives the
`lowest anode voltage at which it is theoretically possible to
`maintain oscillation in the different modes of a magnetron.
`{ 'har'tre ilkwa-zhan }
`Hartree-Fock approximation [QUANT MECH] A refinement
`of the Hartree method in which one uses determinants of single—
`particle wave functions rather than products, thereby introd-
`ucing exchange terms into the Hamiltonian.
`{ 'har~tre lf'ak
`a,prak-so,ma-shen }
`.
`Hartree method
`[QUANT MECH] An iterative variational
`method of finding an approximate wave function for a system
`of many electrons, in which one attempts to find a product of
`single-particle wave functions, each one of which is a solution
`of the Schrodinger equation with the field deduced from the
`charge density distribution due to all the other electrons. Also
`known as self-consistent field method.
`{ ‘har-tré Imeth-od }
`Hartree units
`[ATOM PHYS] A system of units in which the
`unit of angular momentum is Planck’s constant divided by 211',
`the unit of mass is the mass of the electron, and the unit of
`charge is the charge of the electron. Also known as atomic
`units.
`{ 'har-tré ,yii-nots }
`{ 'harts,hom Ioil }
`hartshorn oil See bone oil.
`[ASTRON] A system of classifi-
`Harvard-Draper sequence
`cation of stellar spectra based on features that are found to vary
`in a smooth way from one star to another, and on the star’s
`color.
`{ {har-verd 'dra-por ,se-kwans }
`harvester
`[AGR] A machine used to reap field crops.
`v9~stor ,}
`[AGR] A machine that combines the
`harvester-thresher
`harvesting and threshing of grain crops.
`{ 'har-ve'stor 'thresh'
`or }
`[AGR]
`harvesting
`{ 'har-ve-stin }
`,
`harvest moon [ASTRON] A full moon that is seen nearest the
`autumnal equinox.
`{ ‘harvost [miin }
`harzburgite
`[PETR] A peridotite consisting principally of
`olivine and orthopyroxene.
`{ 'harts.bor,git }
`Harz jig [MIN ENG] A device used to separate coal and foreign
`matter which gives I_ pulsion intermittently with suction.
`{ 'hiirts .jig}
`[CHEM ENG] A thermal reforming process
`Hasche process
`for hydrocarbon fuels; it is a noncatalytic regenerative method
`in which a mixture of hydrocarbon gas or vapor and air is
`passed through a regenerative mass that is progressively hotter
`in the direction of the gas flow; partial combustion occurs,
`
`The gathering of mature field crops.
`
`{ “har-
`
`HARVESTER
`
`
`
`Self-propelled combine.
`(Sperry New Holland, Division
`of Sperry Rand Corp.)
`
`hatchettolite. .
`
`S in 3 Com.
`
`
`
`liberating heat to crack the remaining hydrocarbon
`bustion zone.
`{ 'hash-9 ,pra'sos }
`,
`Hasenclever turntable
`[MIN ENG] A turntable that i
`8 made-
`to rotate by the friction between the positively driven Pulle
`the car, and the table; used as an alternative to the Shunt-bag];
`or the traverser for changing the direction of mine cars or tubs
`eithtir on the surface or underground.
`{ Ihfiz'gn'kleV'srltamltg’.
`bol
`»
`hash [COMPUT SCI] Data which are obviously meanin
`gless,
`caused by human mistakes or computer malfunction. A150.
`known as garbage; gibberish.
`[ELEC] Electric noise PYOduced
`by the contacts of a vibrator or by the brushes of a generator
`or motor.
`[ELECTR] See grass.
`{ hash }
`-
`hash coding See hashing
`{ 'hash ,kod-ig }
`{ ha-
`Hashimoto's disease See
`struma lymphomatosa.
`'
`shi'mo-doz di,zéz }
`{ ha-
`Hashimoto’s struma See
`'
`shi'mo-doz 'stn'i-mo }
`1. A method for converting repre.
`hashing
`[COMPUT SCI]
`sentations of values within fields, usually keys,
`to a more
`compact form.
`2. An addressing technique that uses keys to
`store and retrieve data in a file.
`{ 'hash-in }
`hashish
`[PHARM] A narcotic drug derived from the plant
`Cannabis
`sativa;
`can be
`smoked,
`chewed, or drunk.
`{ 'hash,ésh }
`’
`hash total
`[COMPUT SCI] A sum obtained by adding together
`numbers having different meanings;
`the sole purpose is to
`ensure that the correct number of data have been read by the
`computer.
`~ { 'hash [todel }
`HASP
`[COMPUT SCI] A technique used on some types of
`larger computers to control input and output between a com-
`puter and its peripheral devices by utilizing mass—storage de~
`vices to temporarily store data. Acronym for Houston Auto-
`matic Spooling Processor.
`{ hasp }
`Hassal’s body See thymic corpuscle.
`{ 'has-olz ,bad-é }
`hastate
`[BlOL]
`Shaped like an arrowhead with divergent
`barbs.
`{ 'ha,stat }
`haster
`[METEOROL]
`ter }
`[MINERAL] NaCa2(Fe,Mg)5AIZSi(,032(Ol-l)2 A
`hastingsite
`mineral of the amphibole group crystallizing in the monoclinic
`system and composed chiefly of sodium, calcium, and iron,
`but usually with some potassium and magnesium.
`{'has-
`tin,zit }
`[0RD] Fieldof mines quickly laid as a
`hasty mine field
`protection against an enemy attack; when practicable, it is laid
`in a definite pattern, as is a deliberate field, but measurements
`are approximate rather than exact.
`{ 'has~te 'min lfeld }
`hat
`[COMMUN] To arrange a fixed quantity of symbols or
`groups of symbols in an entirely haphazard sequence, as if they
`had been drawn from a hat.
`{ hat }
`HAT See height above touch—down.
`hatch
`[ENG] A door or opening, especially on an airplane,
`spacecraft, or ship.
`{ hach }
`hatch battens
`[NAV ARCH] Flat bars used to fasten and make
`tight the edges of a tarpaulin covering a hatch.
`{ 'hach ,bat'
`onz }
`hatch beam [ENG] A heavy, portable beam which supports
`a hatch cover.
`{ 'hach IbEm }
`_
`hatch carlings
`[NAv ARCH]
`Fore and aft girders running
`under the coamings 0f hatches, to which the partial or half deck
`beams are attached.
`{ 'hach ,kar-linz }
`hatch. coaming [NAv ARCH] A raised frame around a hatch;
`it forms a support for the hatch cover and strengthens the edges
`of the opening.
`{ ‘hach ,kom-ig }
`hatch cover
`[ENG] A steel or wooden cover for a hatch.
`{ 'hach ,kov-er }
`hatch end beam [NAv ARCH] The deck beam at the fore and
`aft end ofa hatch.
`{ 'hach {end IbEm }
`hatchet
`[DES ENG] A small ax with a short handle and a
`hammerhead in addition to the cutting edge.
`{ 'hach'et }
`hatchettine See hatchettite.
`{ 'ha-chsd.en }
`hatchettite
`[MINERAL] C38H78 A yellow-white mineral pat-
`affin wax, melting at 55'—65°C in the natural state and 79°C [‘1
`the pure state; occurs in masses in ironstone nodules 0f_ “l
`cavities in limestone. Also known as adipocerite; adipocllrer
`hatchettine; mineral tallow; mountain tallow; naphthine.
`i ha-
`chodjt }
`hatchettolite See ellsworthite.
`
`struma
`
`lymphomatosa.
`
`In England, aviolent rain storm.
`
`{ 'has-
`
`{ 'ha-ched-o,1it }
`
`
`
`
`
`
`
`mag/mm
`
`'WW/mrm;wammsaé§ww
`
`.
`
`
`
`