A further note on the activation energy of diffusion
SummaryThe activation energy of diffusion can be expressed in terms of thermodynamic quantities such as entropy and enthalpy of sorption. A substantial simplification to such a published expression is presented.
On the basic equation of sorption and the isosteric heat
SummaryPrecise derivations are given for the basic equation of sorption, -RT ln r = Δh -T Δs. and for the isosteric heat. The prefix Δ indicates the change from sorbed liquid to free liquid. The above basic equation is interpreted as an equilibrium moisture constant (emc) equation. It is shown how Δs/R varies with temperature under the assumption that Δh/l is a function of moisture content only. The above ratios are the obvious non-dimensional expressions for Δh and Δs and these are evaluated for wood as typified by klinki pine (Araucaria klinkii Lauterb.).
The thermodynamics of sorption with reference to klinki pine
SummaryAn investigation into the bonding energy relationships for water in wood indicates that as the temperature increases at constant total moisture content, water moves from within the chemical structure to the adsorption surface. The analysis is evaluated for the wood Araucaria klinkii Lauterb and it is indicated that at 25 °C, less water is held in the chemical structure during adsorption than during desorption.