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Mid-infrared absorption properties of green wood

Dupleix A., de Sousa Meneses D., Hughes M., Marchal R.. 2013. Wood Science and Technology, 47 (6) : p. 1231-1241.

There is a lack of quantitative data on the penetration depth and the amount of energy absorbed by green wood under infrared (IR) radiation. This lack of knowledge is a potential barrier to the development of IR heating as an alternative to soaking as a means of warming logs prior to peeling in the manufacture of plywood. Experimental measurements of normal hemispherical spectral reflectance and transmittance over the range 550¿5,500 cm-1 wavenumbers on four wood species, beech, birch, Douglas-fir and spruce have brought new knowledge on mid-infrared absorption properties of green wood and removed some uncertainties. For instance, it is not possible to deliver energy deeper than up to 0.3 mm below the wood surface because 70¿90 % of all incident IR radiation on the wood surface is absorbed in this layer. Some wood features, such as surface quality, the presence of knots and of free water in wood (the latter two having a more significant effect) influence the amount of energy absorbed. These results illustrate that IR radiation can heat the surface layers, but then heat penetrates deeper into the inside layers of wood by conduction. (Résumé d'auteur)

Mots-clés : propriété physicochimique; pseudotsuga menziesii; picea abies; betula alba; fagus sylvatica; traitement thermique; rayonnement infrarouge; Énergie; absorption; Écorçage; contreplaqué; bois

Thématique : Technologie des produits forestiers

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