Cluster theory for water sorption in wood

Hartley, Ian D.; Kamke, Frederick A.; Peemoeller, H.

doi:10.1007/bf00194465

Cited by 87 publications

(64 citation statements)

References 38 publications

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“…The reorganization of the wood ultrastructure in relation to sorption processes was also reported by Bonarski and Olek (2006). Additionally, Hartley et al (1991) suggested that during sorption processes not only wood components changed the ultrastructure but also bound water molecules might form water clusters. In Eq.…”

Section: Mathematical Modelsupporting

confidence: 58%

Implementation of a relaxation equilibrium term in the convective boundary condition for a better representation of the transient bound water diffusion in wood

2011

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In this work, a relaxation term was added to the convective boundary condition to increase the accuracy of the transient bound water diffusion modeling in wood. The implemented term accounts for a relaxation time constant in the equilibrium moisture content. The inverse finite element analysis approach was used to determine the values of all coefficients of the modified diffusion model. This procedure was performed for beech wood (Fagus sylvatica L.) in the radial and longitudinal directions. The experimental data obtained by Perré et al. (2007) for transient diffusion configurations were used here. The accurate control of moist air parameters and the improved procedure for mass measurements of a sample during sorption experiments were used. The influence of the modification of the boundary condition on accuracy of diffusion modeling was analyzed. Weight function List of symbolsGreek symbols C Points located at the two boundary sides of the domain (two points in the onedimensional model) r Surface emission coefficient (m/s) s Relaxation time (s) X Geometric domain of the R 1 space X Geometric domain of the R 1 space with the boundary

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Section: Mathematical Modelsupporting

confidence: 58%

Implementation of a relaxation equilibrium term in the convective boundary condition for a better representation of the transient bound water diffusion in wood

2011

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“…Freezing bound water exhibits a phase change between -10 and -20°C, whereas non-freezing bound water does not freeze down to -70°C (Berthold et al 1996). Freezing bound water has therefore been assumed to be less confined by and more loosely bound to the cell wall than non-freezing bound water, for example, as water clusters in line with theoretical considerations of Hartley et al (1992) and Hartley and Avramidis (1993). However, Berthold et al (1996) only found freezing bound water in ligno-cellulosic model compounds containing weak or strong acidic groups, that is, not in native wood.…”

Section: Green Wood and Fibre Saturationmentioning

confidence: 96%

A critical discussion of the physics of wood–water interactions

et al. 2012

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This paper reviews recent findings on wood-water interaction and puts them into context of established knowledge in the field. Several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps. The focus of this review is put on water in the broadest concept of wood products, that is, the living tree is not considered. Moreover, the review covers the basic wood-water relation, states and transitions. Secondary effects such as the ability of water to alter physical properties of wood are only discussed in cases where there is an influence on state and/or transition.

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“…BET model theory proposes a multilayer adsorption, a monolayer strongly attached to the chains of the material, and the subsequent layers thermodynamically tend to behave in the same way, however, different from the monolayer and with similar characteristics of liquid water (Hartley et al, 1992). The applicability of the BET model is limited to the low range of a w (0-0.75).…”

Section: Modeling Of Experimental Datamentioning

confidence: 99%

Modelling the effect of temperature on the water sorption isotherms of chitosan films

2016

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The interaction of the water molecules from the environment with foods and other materials can be evaluated using sorption isotherms. Films and biodegradable films are susceptible to changes in their functional characteristics due to adsorbed water. The amount of moisture that biodegradable films can adsorb depends on the temperature, relative humidity of the storage area and chemical composition. Several mathematical models can be used to describe the behavior of sorption isotherms in biodegradable films and some of them have been modified to include the temperature parameter into the equation. In this research, the original and modified BET, GAB, Halsey, Henderson and Dswin models were assessed to determine their suitability describing the behavior of moisture adsorption isotherms of chitosan films at 15, 20, 25 and 30 °C. The modified models of GAB, Dswin and Halsey gave the best fit to the experimental sorption data of the chitosan films, with R 2 values higher than 0.97 demonstrating that those models describe better the sorption isotherms at the temperatures studied.Keywords: chitosan film; moisture adsorption isotherm; GAB model. Practical Application:The knowledge of the relationship between the equilibrium moisture content, equilibrium relative humidity and temperature is very important in order to describe the effect of water activity on storage of foods. Several mathematical models were used to describe the water sorption behavior of chitosan edible films involving water activity, moisture content and temperature.

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Cluster theory for water sorption in wood

Cited by 87 publications

References 38 publications

Implementation of a relaxation equilibrium term in the convective boundary condition for a better representation of the transient bound water diffusion in wood

Implementation of a relaxation equilibrium term in the convective boundary condition for a better representation of the transient bound water diffusion in wood

A critical discussion of the physics of wood–water interactions

Modelling the effect of temperature on the water sorption isotherms of chitosan films

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