Hygroscopic porous materials

P.W. Gibson, M. Charmchi, Coupled heat and mass transfer through hygroscopic porous materials-application to clothing layers, Sen i gakkaishi 53 (5) (1997) 183—194. 

Stakic, M.B. Numerical Study on Hygroscopic Capillary-Porous Material Drying in Packed Bed. EFCE-WPD Technical Meeting, 2002. 

Wood is a hygroscopic, porous, anisotropic and non-homogeneous material. After log sawing, the lumber contains liquid water in fiber cavities (capillary water) and bound water inside the fiber wall (hygroscopic water). Porosity refers to volume fraction of void space. This void space can be actual space filled with air or space filled with both water and air. Capillary-porous materials are sometimes defined as those having pore diameter less than... 

Woody biomass, either gymnosperms (softwoods) or angiosperms (hardwoods) is inherently anisotropic and hygroscopic it is porous material, with the porosity caused by the hollow fibers that make up the woody material. Any number of wood technology texts (see, for example, Haygreen and Bowyer [13]) describe the physical structure of woody biomass. The porosity or void volume of wood exists as macropores—tracheids, rays, resin canals and related structures useful in moving moisture and nutrients within the tree. Chemically, woody biomass is comprised of cellulose, the hemicelluloses, one or another type of lignin, and extractives such as pinoresinol, catechin, pinosylvin, and related compounds. 

Gibson, P Charmchi, M. The Use of Volume-Averaging Techniques to Predict Temperature Transients Due to Water Vapor Sorption in Hygroscopic Porous Polymer Materials, J. Appl. Polym. Sci. 1997, 64,493-505. 

For a number of technical calculations, knowledge of the properties of gases is necessary. For example, this applies to treatment of subjects such as hygroscopic moisture absorption, carbonation of concrete, gas permeability of porous materials, and moisture diffusion in materials. For technical calculations, ideal gases are often assumed, which in most cases is an acceptable assumption. For these kinds of calculations, the concept of ideal gas is briefly explained in the following portions of this section. 

Gibson, P. W. Governing Equations for Multiphase Heat and Mass Transfer in Hygroscopic Porous Media with Applications to Clothing Materials, [Technical Report, Natick/TR-95/004], U.S. Army Natick Research and Development Center, Natick, MA. 1994. 

Bell, J.R. and Nissan, A.H. 1959. Mechanism of drying thick porous bodies during the falling-rate period. II. Hygroscopic material, AIChemE J., 5 344-347. 

Nonporous, capillary-porous, and hygroscopic solution, syrup, mud, gel, extruded material, crystalline, fabric, cardboard, and fiber... 

Wood is a porous, permeable, hygroscopic, and orthotropic material of extreme chemical diversity and physical complexity. Because of this, its properties vary between species, between trees within a species, and even within a tree. This variability can result in an adhesive to produce bonded joints that will perform inconsistently and with different levels of performance among the several types of timber species. 

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