An analysis of moisture diffusion by diffusion equation considering the Coulomb friction

Following a previous paper, another type of diffusion equation accounting for the Coulomb friction is proposed in this paper. For the drying experiments Sitka spruce bars were used with dimensions L×R×T=10×2×2 cm, and the density was 0.4 g/cm3. The specimens were prepared at 20°C and 60% R.H., and were dried in the desiccator with silica gel at 20°C. After 1,200 h, the specimens were cut in half and dried in the desiccator again. The moisture contents were determined by using the oven-dry method and were also calculated from the above theories. The results considering friction are in good agreement with the experimental results. © Springer-Verlag 2003.