e_s "nif(
lowT, e_w,
midT , e_mix,
e_c)" "Surface emissivity change as a function of composition at sample surface"
lowT T<450[K] "Low temperature condition"
midT "T >= 450[K] && T <= 550[K]" "Middle temperature condition"
e_mix "e_w + (T-450[K])/(550[K]-450[K])*(e_c-e_w)" "Surface emissivity at middle temperature condition"
q0 "hconv * (T_gas - T) + sigma_const * e_s * (T_furnace^4 - T^4)" "Heat flux through the sample outer surface"