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Licensed Unlicensed Requires Authentication Published by De Gruyter June 29, 2009

Non-destructive determination and quantification of diffusion processes in wood by means of neutron imaging

  • David Mannes , Walter Sonderegger , Stefan Hering , Eberhard Lehmann and Peter Niemz
From the journal Holzforschung

Abstract

Diffusion processes in samples of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] Karst.) were determined and quantified by means of neutron imaging (NI). The experiments were carried out at the neutron imaging facility NEUTRA at the Paul Scherrer Institute in Villigen (Switzerland) using a thermal neutron spectrum. NI is a non-destructive and non-invasive testing method with a very high sensitivity for hydrogen and thus water. Within the scope of this study, diffusion processes in the longitudinal direction were ascertained for solid wood samples exposed to a differentiating climate (dry side/wet side). With NI it was possible to determine the local distribution and consequently the total amount of water absorbed by the samples. The calculated values scarcely differ from those ascertained by weighing (≤3%). The method yields profiles of the water content over the whole sample, thus allowing the local and temporal resolution of diffusion processes within the sample in the main transport direction (longitudinal). On the basis of these profiles, it was possible to calculate the diffusion coefficients along the fibre direction according to Fick's second law.


Corresponding author. Department of Civil, Environmental and Geomatic Engineering, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland Phone: +41-44-632-3228 Fax: +41-44-632-1174

Received: 2009-2-3
Accepted: 2009-5-11
Published Online: 2009-06-29
Published Online: 2009-06-29
Published in Print: 2009-09-01

©2009 by Walter de Gruyter Berlin New York

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