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 activation energy of diffusion of water in wood
SummaryThe diffusion equation for water in wood is expanded in terms of temperature and moisture gradient on the assumption that the driving force for the diffusion of water in wood is the partial pressure of water vapour. An analytic expression is then developed for the activation energy of diffusion in terms of enthalpy and entropy changes associated with the sorption process. The expression is compared with another published curve and some similarity was observed.
An isostere equation for some common seeds
Abstract Hygroscopy of food seeds affects storage, handling and processing. The thermodynamic relationship upon which the isostere equation is based was originally presented by Othmer. The ratio of latent heats (bound water to free water) is part of the isostere equation and is fitted to data for nine common food seeds using a transition function having logarithmic asymptotes. The isostere equation is completed by the evaluation of a further constant termed the intercept pressure. A reverted form of the isostere equation is also presented to assist with computation.