Experimental Study of the Linear Diffusion of Water in Clonal Eucalyptus Wood
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Experimental Study of the Linear Diffusion of Water in Clonal Eucalyptus Wood Mahyoub Amer1 · Bousselham Kabouchi1 · Mohamed Rahouti2 · Abderrahim Famiri3 · Abdelwahed Fidah3 · Salah El Alami1 · Mohsine Ziani4 Received: 4 April 2020 / Accepted: 27 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract For wood, water diffusivity is an important factor that influences its mechanical and physical properties. In this experimental study, the water absorption and desorption were investigated in linear directions for woods of two Eucalyptus clones; Eucalyptus grandis and Eucalyptus camaldulensis. The diffusion model based on Fick’s second law was applied to assess both water absorption and desorption processes on cubic wood samples of (20 × 20 × 20) mm3. The diffusion coefficient, absorption coefficient, surface emission and diffusivity resistance were estimated. The study of sorption kinetics was carried out at ambient temperature about 25 °C and desorption kinetics at 30 °C for 12 h. The obtained results indicate that the sorption and desorption kinetics as well as the diffused quantities of water in the wood of these two clones were greater in the longitudinal direction than in the radial direction and that they were the lowest in the tangential direction. Wood samples of E. grandis exhibit higher average values of diffusion coefficient, absorption coefficient, and surface emission coefficient in both absorption and desorption processes in the linear directions than those of E. camaldulensis. However, they display lower average values of resistance diffusivity in all directions than those E. camaldulensis in both absorption and desorption processes. Keywords Clonal eucalyptus · Diffusion coefficient · Resistance diffusivity · Surface emission coefficient · Water diffusivity · Wood
1 Introduction Wood is a porous, hygroscopic, anisotropic and complex natural polymer; it has a layered structure. The wood moisture varies constantly with the environmental conditions due to absorption and/or desorption of humidity from the surrounding air [1–4]. * Mahyoub Amer [email protected] Extended author information available on the last page of the article
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International Journal of Thermophysics
(2020) 41:142
Moisture content in wood has an important influence on its physical and mechanical properties, dimensional stability and durability, which limit its uses in construction and numerous applications of engineering [5–9]. Water can be present in two states in wood. The first state called bound water exists in cell walls. The second state or free water is located in the cell lumen and void spaces [10–12]. The water transfer in wood is a very complex process. The mechanism of water diffusion depends on wood density, type of wood, moisture content, relative humidity, temperature, anatomical direction (longitudinal, radial or tangential) and the duration of the exposure [13–17]. The water diffusion coefficient describes the rate of water transfer f
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