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The ratio of the radiation emitted by a surface to the radiation emitted by a blackbody at the same temperature.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ɪmɪˈsɪvɪtɪ; ˌɛm-)
(General Physics) a measure of the ability of a surface to radiate energy; the ratio of the radiant flux emitted per unit area to that emitted by a black body at the same temperature. Symbol: ε
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌɛm əˈsɪv ɪ ti, ˈi mə-)

the ability of a surface to emit radiant energy compared to that of a black body at the same temperature and with the same area.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
According to Harcros, Emisshield Inc's high emissivity ceramic coating technology has expanded its applications into the petrochemical industry by increasing heat transfer in fired heaters, boilers and incinerators processes.
Referring to (1), M(T) is the thermal emissivity of the observed object depending on its temperature (W/[m.sup.2]), [sigma] is the Stefan-Boltzmann constant, and T is the temperature of the black body (K), which is equal to the observed temperature.
Emissivity is a material's physical property that defines its ability to release heat through radiation.
For example, the Split Window algorithm and Day/Night algorithm are used for the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Temperature and Emissivity Separation (TES) algorithm is used for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [4-7].
In this review, we discuss the mean free path of the neutrinos and emissivity of neutrinos from neutron star in Sections 2 and 3, respectively.
[10] and Wu and Yu [11] studied the effects of modified Al on the gloss and IR emissivity. However, these methods mainly concentrated on the effects of modified filler on LIREC.
Each of these models can be classified into direct sky temperature models and atmospheric emissivity correlations.
Thus, a selective coat is required to have a high absorption ([alpha]) in the solar wavelength range and an accompanying low thermal emissivity ([epsilon]) in the near infrared (NIR) and far-infrared (FIR) wavelength ranges.
22-23], they are never made from materials whose emissivity is strongly directional.
The heat sinks seem colder in the images only due to emissivity, because they have the lowest emissivity comparing with transformer, inductor or PCB.
The influence of operating temperature, emissivity of the surface, orientation, and geometries on the total heat loss of the receiver was investigated.