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The ratio of the radiation emitted by a surface to the radiation emitted by a blackbody at the same temperature.


(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


(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.
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.
Each of these models can be classified into direct sky temperature models and atmospheric emissivity correlations.
And in most cases the camera readings need to be adjusted to take this emissivity into account.
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.
One big source of error in temperature measurements of MCMs with an infrared camera is the emissivity variation over their surface.
The painted asphaltic surface showed high thermal emissivity and lost about half of its initial albedo (solar reflectance) within two years.
A common example is the use of a high emissivity coating (e.
However few studies investigate the measurement of emissivity of calibration load which is essential for industrial application.
Low-E or low emissivity glasses act like transparent thermal insulations and they have much lower heat transfer comparing to normal glasses.
The coating line will be up and running from October 2012 and will produce high performance, low emissivity glazing products to complement Pilkington's renowned K Glass, as well as its solar control glass products.