Modelling the process of absorption and desorption of water in two dimensions (transverse) in a square wood beam

Mounji, H.; Bouzon, J.; Vergnaud, J.M.

doi:10.1007/bf00225689

Cited by 11 publications

(8 citation statements)

References 9 publications

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“…The moisture absorbed into the wood takes place due to the capillary force and presence of accessible hydroxyl groups when the MC is below the fibre saturation point (FSP). Above the FSP, free water moves into wood as a result of capillary forces [22,23]. This pressure force is related to a moisture and air gradient of nearby cells.…”

Section: Of Solid Woodmentioning

confidence: 99%

Combining electrical resistance and 3-D X-ray computed tomography for moisture distribution measurements in wood products exposed in dynamic moisture conditions

Bulcke

Windt

et al. 2013

Building and Environment

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Strength and durability of wood-based products are substantially influenced by moisture. It is, therefore, crucial to monitor the moisture content (MC) distribution in wood products to fully understand their behaviour in dynamic moisture conditions. In this paper, we present a combined X-ray CT method and an adapted version of the electrical resistance MC measurement method for detailed studies on MC distribution in wood products. The X-ray CT method is evaluated using the gravimetrically recorded MC of solid wood. Subsequently, the recorded MC of electrical method is evaluated by using X-ray CT method. Three wood products are used for this purpose, i.e. solid wood, plywood and oriented strand board (OSB) panels. It is proven that X-ray CT method can accurately determine the MC of wood products and thus has great potential for non-destructively measuring the MC distribution in 3D. Furthermore, the results show that electrical method can effectively record the local MC when the MC distribution in this region is even. Otherwise, the position of the electrodes, with regard to specific wood properties has a substantial influence on its performance. Compared with solid wood and OSB, the electrical method performs best in plywood due to its layered structure. The adapted electrical method is an effective tool for continuously monitoring the MC distribution of wood products, taking into account that the electrodes are installed correctly according to the structure of the material and research questions. Combined with X-ray CT scanning, MC distribution of wood-based products under in-service applications, can be monitored.

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Section: Of Solid Woodmentioning

confidence: 99%

Combining electrical resistance and 3-D X-ray computed tomography for moisture distribution measurements in wood products exposed in dynamic moisture conditions

Bulcke

Windt

et al. 2013

Building and Environment

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“…In solving the diffusion equation for moisture variations in wood, some authors have assumed that the diffusion coefficient depends strongly on moisture content (e.g., Hougen et al 1940, Meroney 1969, Simpson 1993, Skaar 1954, Van Arsdel 1947, while others have taken the diffusion coeffi cient as constant (e.g., Avramidis and Siau 1987, Choong and Skaar 1972, Droin et al 1988, Mounji et al 1991, Soderström and Salin 1993. Also, different boundary conditions have been assumed by different authors (e.g., Crank 1975, Plumb et al 1985, Salin 1996, Hukka 1999.…”

Section: Introductionmentioning

confidence: 99%

An Inverse Moisture Diffusion Algorithm for the Determination of Diffusion Coefficient

2001

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The finite difference approximation is applied to estimate the moisture-dependent diffusion coefficient by utilizing test data of isothermal moisture desorption in northern red oak (Quercus rubra). The test data contain moisture distributions at discrete locations across the thickness of specimens, which coincides with the radial direction of northern red oak, and at specified times. Also, the rate of moisture variation at each specified time and location must be known or correctly esti mated. The functional form of the diffusion coefficient as well as the boundary conditions at the surfaces are not known a priori. The resulting system of finite difference equations defines an inverse problem, whose solution may be sensitive *Corresponding author. E-mail: jliu@fs.fed.us † The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright. 1555Published by Marcel Dekker, Inc.www.dekker.com LIU, SIMPSON, AND VERRILLto small changes of input data. Results indicate that the diffu sion coefficient increases with increasing moisture content below the fiber saturation point, which defines the upper limit applied by the diffusion theory.

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“…Many studies have been made on wood in contact either with moisture (Skaar 1958;Stamm 196o;Comstock 1963;Choong 1965;Moscher and Martin 1968;Droin et al, 19881;Droin et al, 19882;Droin et al, 19891;Droin et al, 19892) or with liquid water (Mounji et al, 19911;Mounji et al, 19912;Mounji et al, 19913;El Kouali and Vergnaud, 1991;E1 Kouali et al, 1991;Mounji and Vergnaud, 1992; E1 Kouali et al, 1992). In both these cases, the matter transfer through the wood can be successfully described by a diffusional process (Skaar 1958;Stamm 196o;Cornstock 1963;Choong 1965;Moscher and Martin, 1968;Droin et al, 1988 x, Droin et al, 19882;Droin et al, 19891;Droin et al, 19892;Mounji et al, 19911;Mounji et al, 19912;Mounji et al, 19913; E1 Kouali and Vergnaud, 1991;E1 Kouali et al, 1991E1 Kouali et al, , 1992Mounji and Vergnaud, 1992), in spite of the fact that the driving force may be the pressure gradient instead of a gradient of concentration (Bramhall 1976).…”

Section: Introductionmentioning

confidence: 99%

“…In both these cases, the matter transfer through the wood can be successfully described by a diffusional process (Skaar 1958;Stamm 196o;Cornstock 1963;Choong 1965;Moscher and Martin, 1968;Droin et al, 1988 x, Droin et al, 19882;Droin et al, 19891;Droin et al, 19892;Mounji et al, 19911;Mounji et al, 19912;Mounji et al, 19913; E1 Kouali and Vergnaud, 1991;E1 Kouali et al, 1991E1 Kouali et al, , 1992Mounji and Vergnaud, 1992), in spite of the fact that the driving force may be the pressure gradient instead of a gradient of concentration (Bramhall 1976). The main characteristics of the absorption process of moisture or water are the following: i) The wood is an anisotropic material with three main axes of diffusion, ii) The three main diffusivities are quite different, the longitudinal diffusivity being much larger than the other two.…”

Section: Introductionmentioning

confidence: 99%

“…The main characteristics of the absorption process of moisture or water are the following: i) The wood is an anisotropic material with three main axes of diffusion, ii) The three main diffusivities are quite different, the longitudinal diffusivity being much larger than the other two. iii) A rather low amount of water is absorbed when the wood is in contact with moisture, while a larger amount is absorbed when the wood is immersed in water (Mounji et al, 19911;Mounji et al, 19912;Mounji et al, 19913;E1 Kouali and Vergnaud, 1991;E1 Kouali et al, 1991E1 Kouali et al, , 1992Mounji and Vergnaud, 1992). iv) The diffusivities are concentration-dependent when the wood sample is in contact with moisture in air (Skaar 1958;Stamm 196o;Comstock 1963;Choong 1965;Moscher and Martin 1968;Droin et al, 19881, Droin et al, 19882;Droin et al, 19891;Droin et al, 19892).…”

Section: Introductionmentioning

confidence: 99%

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Process of absorption and desorption of methanol with a 3-dimensional transport through Picea wood

et al. 1994

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The process of absorption of methanol in liquid state by a wood sample, as well as the following step of desorption, is studied. A 3-dimensional transfer takes place within a cubic wood sample, this cube being cut in such a way that the sides of the cube are parallel with the longitudinal, radial and tangential axes of diffusion. A numerical model taking into account all the facts, e. g. diffusion within the solid and constant concentration on the surface during the stage of absorption, and diffusion within the solid and evaporation from the surface during the stage of desorption, is built and successfully tested. A pseudo-equilibrium of absorption is attained after an immersion time of about 3 hours in the liquid, and the whole amount of methanol is evaporated during the stage of desorption. The process can be described by a 3-dimensional diffusion with constant principal diffusivities.

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Modelling the process of absorption and desorption of water in two dimensions (transverse) in a square wood beam

Cited by 11 publications

References 9 publications

Combining electrical resistance and 3-D X-ray computed tomography for moisture distribution measurements in wood products exposed in dynamic moisture conditions

Combining electrical resistance and 3-D X-ray computed tomography for moisture distribution measurements in wood products exposed in dynamic moisture conditions

An Inverse Moisture Diffusion Algorithm for the Determination of Diffusion Coefficient

Process of absorption and desorption of methanol with a 3-dimensional transport through Picea wood

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