Study of Restricted Diffusion in Wood

An NMR study of restricted diffusion of water in Douglas-fir wood was undertaken using the pulsed field gradient method. The measurements were performed at 25 C and at two different moisture contents. Analysis of the results shows that the restricted diffusion of water molecules in this sample can be adequately described using a restricted diffusion model that considers diffusion to occur between infinite planar barriers. Two different barrier separations were incorporated into the model in order to obtain a good correspondence between the calculated and experimental results. Excellent agreement exists between parameters deduced from the NMR measurements and known anatomical data.