Electro osmotic pulsing technology has been transferred from civil engineering field to the wood protection field. In civil engineering the system is used for drying porous material and keeping them at a certain moisture level. This is achieved by employing a definite set- up and a fixed pulse pattern. In wood protection electric field is noted to defend wood from fungal attack. One suggested reason is that fungi are unable to get nutrition because of the occurring water movement under applied electric field.
The wood protection application uses different set-up than the electro osmotic drying system therefore water transport in wood has not yet been documented and only hypotheses have been made on that topic.
A test was conducted to determine water uptake of pine sapwood (Pinus sylvestris L.) and beech wood (Fagus sylvatica). Wood samples were attached to the pulse generator and an electric field was applied. Test samples were exposed to different relative humidity while the temperature of the test remained the same. The test started at a low relative humidity and gradually advanced to high humidity. The test samples were compared to reference samples without external electric field.
Throughout the test the samples were attached to a current logger to determine the relationship between wood moisture content and the running current penetrating the samples. The detected current was small since most of the testing occurred under fiber saturation point.
The equilibrium moisture content of electro pulses samples was recorded to be higher than the reference samples without external electric field. This trend was observed in both wood species.
Keywords: sorption under pulsating electric field, wood protection
Authors
Kängsepp K.
Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås
Militz H.
Department of Wood Biology and Wood Products, Georg-August-Universität Göttingen, Göttingen
Larnøy E.
Norwegian Forest and Landscape Institute, Ås
Goodell B.
Department of Sustainable Biomaterials, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
Salbu B.
Norwegian University of Life Sciences, Ås
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