Implementation of sorption hysteresis in multi-Fickian moisture transport
-
Henrik Lund Frandsen
Abstract
In the cellular structure of wood, bound-water diffusion and water-vapor diffusion interact via sorption in a complex moisture-transportation system. At low relative humidities, moisture transport may be modeled by a Fickian diffusion equation with a good approximation. At higher relative humidities, slow sorption and faster bound-water diffusion cause effects, which have been referred to as non-Fickian or anomalous, as they cannot be modeled by one Fickian diffusion equation. Previous research has demonstrated that a set of coupled diffusion equations, namely the multi-Fickian model, can represent this behavior. The multi-Fickian model describes the combined transport of bound water and vapor and their interaction through sorption. The bound-water concentration is also influenced by sorption hysteresis. In the worst case, sorption hysteresis may result in deviations of up to 30–35% in moisture content. Hence, for a precise moisture content computation, sorption hysteresis must be taken into account. The present paper explains the relation between sorption hysteresis and multi-Fickian moisture transport, and clarifies how models for the two phenomena are coupled. To illustrate the effects, a finite element simulation, which is based on the combined model, is presented.
©2007 by Walter de Gruyter Berlin New York
Articles in the same Issue
- Acknowledgement
- Subject index
- Contents Volume 61 (2007)
- Author index
- Species index (scientific names)
- Meetings
- Improvement of Pinus pinaster Ait elite trees selection by combining near infrared spectroscopy and genetic tools
- Direct method for the determination of phenolic hydroxyl groups in pulp
- Comparative effect of ozone, chlorine dioxide, and hydrogen peroxide on lignin: Reactions affecting pulp colour in the final bleaching stage
- Structural modification of eucalypt pulp lignin in a totally chlorine-free bleaching sequence including a laccase-mediator stage
- Analysis of wood tissues by time-of-flight secondary ion mass spectrometry
- Isolation and identification of residual chromophores from aged bleached pulp samples
- Studies on oxidative modifications of cellulose in the periodate system: Molecular weight distribution and carbonyl group profiles
- Lignin-carbohydrate network in wood and pulps: A determinant for reactivity
- Cross polarisation/magic angle spinning 13C-NMR spectroscopic studies of cellulose structural changes in hardwood dissolving pulp process
- Fungal decay of spruce and beech wood assessed by near-infrared spectroscopy in combination with uni- and multivariate data analysis
- Paper mill sludge as a component of wood adhesive formulation
- Implementation of sorption hysteresis in multi-Fickian moisture transport
- Time/temperature equivalence in the dry wood creep response
- Neural network prediction of bending strength and stiffness in western hemlock (Tsuga heterophylla Raf.)
- Bending properties of particleboard and MDF layers
- Gold as an X-ray CT scanning contrast agent: Effect on the mechanical properties of wood plastic composites
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
Articles in the same Issue
- Acknowledgement
- Subject index
- Contents Volume 61 (2007)
- Author index
- Species index (scientific names)
- Meetings
- Improvement of Pinus pinaster Ait elite trees selection by combining near infrared spectroscopy and genetic tools
- Direct method for the determination of phenolic hydroxyl groups in pulp
- Comparative effect of ozone, chlorine dioxide, and hydrogen peroxide on lignin: Reactions affecting pulp colour in the final bleaching stage
- Structural modification of eucalypt pulp lignin in a totally chlorine-free bleaching sequence including a laccase-mediator stage
- Analysis of wood tissues by time-of-flight secondary ion mass spectrometry
- Isolation and identification of residual chromophores from aged bleached pulp samples
- Studies on oxidative modifications of cellulose in the periodate system: Molecular weight distribution and carbonyl group profiles
- Lignin-carbohydrate network in wood and pulps: A determinant for reactivity
- Cross polarisation/magic angle spinning 13C-NMR spectroscopic studies of cellulose structural changes in hardwood dissolving pulp process
- Fungal decay of spruce and beech wood assessed by near-infrared spectroscopy in combination with uni- and multivariate data analysis
- Paper mill sludge as a component of wood adhesive formulation
- Implementation of sorption hysteresis in multi-Fickian moisture transport
- Time/temperature equivalence in the dry wood creep response
- Neural network prediction of bending strength and stiffness in western hemlock (Tsuga heterophylla Raf.)
- Bending properties of particleboard and MDF layers
- Gold as an X-ray CT scanning contrast agent: Effect on the mechanical properties of wood plastic composites
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
