Contemporary Examples. 1  He campaigned and governed in poetry, and we are all the richer for it. 2  Its essays, criticism, reportage, and poetry are not âproduct.â. 3  Laskey, who earned a degree in psychology, enjoys painting and poetry. 4  poetry would be too obvious, too âportrait of the artist as a young nuisanceâ.
Low emissivity - Definition. 1  Emissivity is the value given to materials based on the ratio of heat emitted compared to a perfect blackbody, on a scale from zero to one. A blackbody would have an emissivity of 1 and a perfect reflector would have a value of 0.
(1) Where P (watts) is the radiated power from a body of area A (m2) at temperature T (K). Îµ is emissivity, a dimensionless number between 0 and 1 that determines the. efficiency of a body to radiate and absorb energy. A perfect radiator and absorber has an emissivity of 1. Soil, ice, rock, asphalt and human skin have emissivities slightly less than 1. Ï -8is the Stefan-Boltzmann constant, 5.67 x10 Wm-2T-4 T is the body temperature in Kelvin. So if absolute temperature (in Kelvin degrees) doubles, radiated power increases by a factor of sixteen. Also, changes in temperature alter radiation peak wavelengths. Temperature increases move peak radiation to smaller wavelengths and vice-versa. Equilibrium and Solid Angles