Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2005
Sammendrag
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Sammendrag
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Sammendrag
In recent years chitosans have been investigated as a natural chemical for wood preservation against fungal decay, and chitosan in aqueous solutions has been used in impregnation studies. To evaluate the retention of chitosan after an impregnation process and to evaluate the fixation of chitosan in wood a method for determination of chitosan in wood and water samples has been developed based on acidic hydrolysis of chitosan to glucosamine followed by online derivatization by o-phthalaldehyde, chromatographic separation and fluorescent detection. For wood samples the method was linear up to 45mgg−1 chitosan in wood and had a recovery of 86%. The yield of chitosan in water was 87% at 1%(w/v) concentration.
Sammendrag
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Sammendrag
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Sammendrag
The uptake of chitosan based impregnation solutions were tested on Scots pine (Pinus sylvestris L), Beech (Fagus sylvatica L.), Downy birch (Betula pubescens Ehrh.) and Norway spruce (Picea abies L. Karst.) in longitudinal, radial and tangential directions separately. The four chitosans tested had a fraction of acetylated residues (FA) of 0.198 and average molecular weights ranging from 18 to 129kDalton. The kinetic viscosity of the 2.4% (weight/volume) solutions at pH 5.0 was in the range of 2.95 to 28.8mm2s-1. The general trend showed that there was an increase in uptake of chitosan based impregnation solutions with decreasing viscosity, and the chitosan solution with the lowest viscosity had almost comparable uptake with water for Pine and Beech in the longitudinal direction. In general, the lower the ability for uptake of impregnation solution, the more the viscosity influences the uptake.
Forfattere
Gry AlfredsenSammendrag
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Forfattere
Gry AlfredsenSammendrag
Det er ikke registrert sammendrag
Sammendrag
In this study modified wood samples were tested according to the extended standardised test procedures of ENV 807 (3 types of soils). A Round Robin test was carried out at two laboratories: Swedish National Testing and Research Institute and Norwegian Forest Research Institute.The different soil types used were conifer forest soil (pH 4.6), soil from the Simlngsdalen test field (pH 5.2) and garden compost soil (pH 7.4). The wood modifications used were furfurylation (Visorwood), acetylation and heat treatment (Thermowood). Other materials tested were linseed oil impregnated pine, reference preservative (CC and CCA) treated pine and Robinia psuedoaccacia heartwood.A dynamic MOE (MOEdyn) test device based on measurement of ultrasonic pulse propagation was used for non-destructive decay strength evaluation during the incubation period. The MOE values were correlated to measured decay mass loss of the test specimens after different periods of exposure to the soils. Type of fungal attack was also evaluated using light microscopy.Results from preliminary studies indicate that ultrasound seems to be an excellent tool for evaluation of early brown rot decay. It also seems to be feasible for detecting white rot. However it does not seem to be very accurate in evaluating early stages of soft rot decay.
Sammendrag
Wood samples treated with ammonium copper quat (ACQ 1900 and ACQ 2200), chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes on the surface of the weathered samples were characterized by roughness and color measurements on the samples with 0, 200, 400 and 600 h of total weathering.The objective of this study was to investigate the changes created by weathering on impregnated wood with several different wood preservatives. This study was performed on the accelerated weathering test cycle, using UVirradiation and water spray in order to simulate natural weathering. Surface roughness and color measurement was used to investigate the changes after several intervals (0200400600 h) in artificial weathering of treated and untreated wood.