Water Vapor Diffusion in Relatively Dry Soil: III. Steady-State Experiments1
- Ray D. Jackson2
Steady-state water vapor diffusion coefficients were measured for sorption and desorption on Adelanto loam and Pachappa loam at 27°C. The sorption diffusivities for both soil materials increase, and then decrease, with increasing water content. The desorption diffusivities for Adelanto loam are constant throughout the water content range studied, whereas the desorption diffusivities for the Pachappa loam exhibit a maximum similar to the sorption diffusivities. For both soil materials the transient and the steady-state diffusivity-water content curves have nearly the same shape and magnitude. Diffusivities calculated from adsorption isotherm data are similar to the measured diffusivities. Comparison of data from the three methods indicates that liquid diffusion becomes noticeable at water contents corresponding to relative pressures of 0.5 to 0.7 for Adelanto and 0.8 to 0.9 for Pachappa.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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