A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
-
Henrik Lund Frandsen
Abstract
This paper presents a study and a refinement of the sorption rate model in a so-called multi-Fickian or multi-phase model. This type of model describes the complex moisture transport system in wood, which consists of separate water vapor and bound-water diffusion interacting through sorption. At high relative humidities, the effect of this complex moisture transport system becomes apparent, and since a single Fickian diffusion equation fails to model the behavior, it has been referred to as non-Fickian or anomalous behavior. At low relative humidities, slow bound-water transport and fast sorption allow a simplification of the system to be modeled by a single Fickian diffusion equation. To determine the response of the system, the sorption rate model is essential. Here the function modeling the moisture-dependent adsorption rate is investigated based on existing experiments on thin wood specimens. In these specimens diffusion is shown to be negligible, allowing a separate study of the adsorption rate. The desorption rate has been observed to be slower at higher relative humidities as well, and an expression analogous to the adsorption rate model is proposed. Furthermore, the boundary conditions for the model are discussed, since discrepancies from corresponding models of moisture transport in paper products have been found.
©2007 by Walter de Gruyter Berlin New York
Articles in the same Issue
- Meetings
- Chemical composition of 36 Brazilian Amazon forest wood species
- Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp
- Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion
- Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
- Synthesis of light-colored rosin glycerol ester
- Studies on fluorescence of cellulosics
- Fluorescence spectroscopy for chromophore studies on bleached kraft pulps
- Influence of surface structure on wetting of coated offset papers
- Fundamental study of the interaction of Ti atoms with spruce surfaces
- Surface analysis of groundwood paper treated by diffuse coplanar surface barrier discharge (DCSBD) type atmospheric plasma in air and in nitrogen
- Ultrastructural aspects of fibre development during the stone groundwood process: New insights into derived pulp properties
- Stabilization of peracetic acid with aspartic acid diethoxy succinate (AES)
- Stabilization of H2O2 in the presence of Fe(II) and Mn(II) impurities under alkaline conditions
- Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
- Thermoforming of wood veneer composite sheets
- A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
- Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test
- Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test
- Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests
- Insecticidal activity of essential oil from Chamaecyparis formosensis Matsum
- Knotwood as a window to the indirect measurement of the decay resistance of Scots pine heartwood
- Field assessment of wood stake decomposition in forest soil
Articles in the same Issue
- Meetings
- Chemical composition of 36 Brazilian Amazon forest wood species
- Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp
- Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion
- Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
- Synthesis of light-colored rosin glycerol ester
- Studies on fluorescence of cellulosics
- Fluorescence spectroscopy for chromophore studies on bleached kraft pulps
- Influence of surface structure on wetting of coated offset papers
- Fundamental study of the interaction of Ti atoms with spruce surfaces
- Surface analysis of groundwood paper treated by diffuse coplanar surface barrier discharge (DCSBD) type atmospheric plasma in air and in nitrogen
- Ultrastructural aspects of fibre development during the stone groundwood process: New insights into derived pulp properties
- Stabilization of peracetic acid with aspartic acid diethoxy succinate (AES)
- Stabilization of H2O2 in the presence of Fe(II) and Mn(II) impurities under alkaline conditions
- Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
- Thermoforming of wood veneer composite sheets
- A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
- Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test
- Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test
- Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests
- Insecticidal activity of essential oil from Chamaecyparis formosensis Matsum
- Knotwood as a window to the indirect measurement of the decay resistance of Scots pine heartwood
- Field assessment of wood stake decomposition in forest soil
