Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions
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Walter Sonderegger
,
Manuele Vecellio
Abstract
The combined bound water and water vapour diffusion of wood is of great interest in the field of building physics. Due to swelling stresses, the steady-state-determined diffusion coefficient clearly differs from the unsteady-state-determined diffusion coefficient. In this study, both diffusion coefficients and the water vapour resistance factor of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) were investigated for the principal anatomical directions (radial, tangential and longitudinal) and in 15° steps between these directions. The values were determined with the cup method as the basic principle. The unsteady-state-determined diffusion coefficient is, independent of the direction, about half that of the steady-state-determined diffusion coefficient. Both diffusion coefficients are about two to three times higher for spruce than for beech. They are up to 12 times higher in the longitudinal direction than perpendicular to the grain for spruce, and up to 15 times higher for beech. With increasing moisture content, the diffusion coefficients exponentially increase. The water vapour resistance factor shows converse values to the diffusion coefficients.
©2011 by Walter de Gruyter Berlin Boston
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- Meetings
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Articles in the same Issue
- Original Papers
- Fundamental understanding of pulp property development under different thermomechanical pulp refining conditions as observed by a new Simons’ staining method and SEM observation of the ultrastructure of fibre surfaces
- Enhancing dewatering of thermo-mechanical pulp (TMP) based papermaking through enzymatic treatment
- Mechanisms of TMP peroxide bleaching using Mg-based alkalis
- Properties of wood chips for thermomechanical pulp (TMP) production as a function of spout angle
- Determination of local material properties of OSB sample by coupling advanced imaging techniques and morphology-based FEM simulation
- Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions
- Oxygen plasma-treated enzymatic hydrolysis lignin as a natural binder for manufacturing biocomposites
- Influence of the adhesive formulation on the mechanical properties and bonding performance of polyurethane prepolymers
- Characterizing perpendicular-to-grain compression (C⊥) behavior in wood construction
- Predicting the strength of Populus spp. clones using artificial neural networks and ε-regression support vector machines (ε-rSVM)
- X-ray scattering and microtomography study on the structural changes of never-dried silver birch, European aspen and hybrid aspen during drying
- Equilibrium moisture content (EMC) in Norway spruce during the first and second desorptions
- Fungal degradation of bamboo samples
- qPCR as a tool to study basidiomycete colonization in wooden field stakes
- Meetings
- Meetings
