A = surface area of the opaque solid boundary a = spectral radiation exergy loss per unit surface a = spectral radiation exergy loss per unit volume c = speed of light eM; = local net exergy increment in the wall medium due to absorbing spectral radiation heat eR; = local net increment of spectral radiation exergy in the radiative field at the opaque wall eM; = local net exergy increment of the semitransparent medium due to absorbing spectral radiation heat eR; = local net increment of spectral radiation exergy in radiative field in the semitransparent medium h = Planck’s constant Ib; = spectral radiative intensity of the blackbody I = spectral radiative intensity Lb; = spectral radiative entropy intensity of the blackbody L = spectral radiative entropy intensity nw = unit outward normal vector of the boundary wall Q = net spectral radiation heat absorbed by matter r = position vector SG; = local spectral radiative entropy generation due to radiation processes at the opaque solid wall S G; = local spectral radiative entropy generation due to absorption and emission processes in the semitransparent medium SG; = local spectral radiative entropy generation due to scattering processes in the semitransparent medium s = direction vector TM = medium temperature T = spectral radiation temperature T0 = temperature of environment V = volume a; = spectral absorption coefficient s; = spectral scattering coefficient = wavelength = single scattering phase function = spectral radiative exergy intensity = solid angle