screening

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screening

[′skrēn·iŋ]
(atomic physics)
The reduction of the electric field about a nucleus by the space charge of the surrounding electrons.
(electromagnetism)
(engineering)
The separation of a mixture of grains of various sizes into two or more size-range portions by means of a porous or woven-mesh screening media.
The removal of solid particles from a liquid-solid mixture by means of a screen.
The material that has passed through a screen.
(industrial engineering)
The elimination of defective pieces from a lot by inspection for specified defects. Also known as detailing.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

screening

the use of academic qualifications as a means of selecting among candidates for employment, where it is the general level of academic qualification which is decisive rather than the particular content of the education. In this process, an employer may use educational qualifications, or sometimes also the type of institution attended, as a proxy for ‘general intelligence’, ‘perseverance and motivation’, or other 'social background’, instead of being interested in the specific content of the education received. see also CULTURAL CAPITAL.

According to the screening hypothesis, it is the screening process rather than any direct economic return on education which explains part of the correlation between level of education and level of income. This hypothesis provides an account of the effects of education which is at odds with other hypotheses (compare HUMAN CAPITAL). See also CREDENTIALISM, CULTURAL CAPITAL.

Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Screening

 

the sorting on screens of bulk materials according to particle size. Screening is used to separate coal, ore. building materials, and other bulk materials into fractions or to sort out particles of a given size. For example, in the production of crushed gravel (about 200 million cu m in the USSR in 1970). a mass of raw sand and gravel is sorted out into five fractions (70–40 mm. 40–20 mm, 20–10 mm, 10–5 mm, and less than 5 mm). During screening, the material is separated into layers as it moves along the sieve of the screen: the larger the particles, the higher the layer along which they move. Particles that are smaller than the screen openings (so-called lower grade) fall through the openings upon reaching the screen’s surface (screen underflow); larger particles (so-called upper grade) slide along the sieve and form the screen overflow. Because of limitations on the length of the screen, not all particles that are smaller than the sieve openings fall through; some remain in the screen overflow, contaminating it and reducing the quantity of the underflow.

The efficiency of screening depends on many factors: the size and shape of the particles in the initial material and the load it exerts on the screen, the type of screen, and the size and shape of the openings in the sieve, its length, and its angle of inclination. The maximum efficiency of trommels is 60–70 percent: of shaking screens. 70–80 percent; and of vibrating screens, 90–98 percent. Screening on sieves with openings of 3 mm and more is widespread in industry; openings of 1 mm are rarely encountered. Hydraulic classification or air separation is usually used to sort materials containing particles smaller than 1–3 mm. Since screening ensures high-quality sorting, its use is spreading, particularly the use of sieves with small openings.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

Screening

A mechanical method of separating a mixture of solid particles into fractions by size. The mixture to be separated, called the feed, is passed over a screen surface containing openings of definite size. Particles smaller than the openings fall through the screen and are collected as undersize. Particles larger than the openings slide off the screen and are caught as oversize. A single screen separates the feed into only two fractions. Two or more screens may be operated in series to give additional fractions. Screening occasionally is done wet, but most commonly it is done dry.

Industrial screens may be constructed of metal bars, perforated or slotted metal plates, woven wire cloth, or bolting cloth. The openings are usually square but may be circular or rectangular. See Mechanical classification, Mechanical separation techniques, Sedimentation (industry)

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.

screening

The application of technical or other means which are intended to detect weapons, explosives or other dangerous devices that may be used to commit an act of unlawful inference (ICAO).
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
The results of this study concluded that no significant difference was observed in terms of knowledge difference between fathers and mothers for the provision of prenatal screening services but fathers were more aware regarding provision of premarital screening.
Moreover, MR must be understood in the context of the Danish prenatal screening program that has a very consistent and high uptake (>90%) [20].
Current screening guidelines recommend early prenatal screening for syphilis and other sexually transmitted infections (STIs), because untreated infections can lead to adverse perinatal outcomes.
[5] Nonstandard abbreviations: cfDNA, cell-free DNA; NIPS, noninvasive prenatal screening; MPS, massively parallel sequencing; NGS, next-generation sequencing; NiPS, NGS- independent prenatal screening; HLPA, high-throughput ligation-dependent probe amplification; MLPA, multiplex ligation-dependent probe amplification; SNP, single-nucleotide polymorphism.
Study limitations included the fact that pregnant women tested via routine syphilis testing instead of the Provincial Prenatal Screening Program would not have been identified through our study methodology.
Also, parameters for prenatal screening for irregular erythrocyte antigens and infectious diseases during pregnancies are preferably measured in the first trimester.
that informed-consent practices for prenatal screening tend to be
Doctors have done prenatal screening for decades, but previous methods involved inserting a needle into the mother's uterus to sample tissue directly from the fetus.
Contributed by neonatal, radiology, obstetrics, and pediatric specialists from North America, the UK, and Australia, the 13 chapters overview the principles of radiological investigation of the neonate, including a team approach to imaging; evidence-based use of imaging and issues of reliability and validity; and images and description of indications, appearances, and interpretation common to neonatal pathology, in various body systems and for congenital heart disease, metabolic diseases, prenatal screening, placement of catheters and tubes, and antenatal diagnosis of selected defects.
over the last several decades, the use of prenatal screening
Recently, Schackman and colleagues reported on the use of prenatal screening for syphilis in Haiti and concluded that it could be an effective tool for solving the problem (2).