Mass Diffusivity of Beech Determined in Unsteady-State Using a Magnetic Suspension Balance

Abstract

This article presents an experimental device and the procedure used to determine the mass diffusivity coefficient of beech from adsorption/desorption cycles. The experimental device is built around a magnetic suspension balance that is able to achieve accurate mass measurements over a wide range of temperature and relative humidity. The value of mass diffusivity is determined using a slope method from the transient period of relative humidity steps. Experimental values are presented for beech in longitudinal and tangential directions.

Influence of geometrical structure on sorption isotherms of Jersey and yarns made of cotton at two temperatures

“…The software, developed in Visual Basic, also controls the position of the magnetic coupling in order to avoid the balance shift by tarring at regular time intervals. This automatic procedure removes any balance drift even over very long periods of time [43]. This is a very important advantage of the magnetic suspension balance.…”

“…1. The balance and the electromagnet are completely disconnected from the measuring cell in order to avoid disturbance that may be generated by high values of temperature and pressure [43,44]. The balance and the upper part of the electromagnet are in an ambient environment.…”

“…Two different vertical positions of the suspension magnet can be chosen [43]. They correspond to two different measuring positions ( Fig.…”

Implementation of a relaxation equilibrium term in the convective boundary condition for a better representation of the transient bound water diffusion in wood

“…The sorption experiments were made in a setup designed and built in LERFoB, AgroParisTech, Nancy France (Perré et al 2007). In the setup, the concept of a magnetic suspension balance was used.…”

“…This procedure was performed for beech wood (Fagus sylvatica L.) in the radial and longitudinal directions. The experimental data obtained by Perré et al (2007) for transient diffusion configurations were used here. The accurate control of moist air parameters and the improved procedure for mass measurements of a sample during sorption experiments were used.…”