C is the specific heat capacity of the particle, [T.sub.p] is the particle temperature, [T.sub.air] is the ambient air temperature, h is the heat transfer coefficient, [h.sub.m ] is the mass transfer coefficient, [L.sub.subl], is the latent heat of sublimation, [[omega].sub.air] is the water vapor mass fraction in the ambient air, and [[omega].sub.p] is the water vapor mass fraction at the particle surface.