Your search resulted in 336 documents. Displaying 25 entries per page.
Lignin degradation by a non-enzymatic system supposed to be active in white rot fungi
2000 - IRG/WP 00-10340
Electron microscopic investigations have shown that ligninolytic enzymes of white-rot fungi are only able to penetrate the wood cell wall in late stages of degradation. Thus, the selective degradation of lignin of certain white-rot fungi can only be explained on the basis of a low molecular weight, highly diffusible system. A system, consisting of copper, a coordination compound and either H2O2 or...
P Lamaipis, W Gindl, T Watanabe, K Messner
Aspects of leaching
1976 - IRG/WP 267
With respect to Document No: IRG/WP/246, and the recommendation that an economic leaching test can be based on a non-changing volume of water (500 ml/block), I would like to relate our experiences with this suggestion. Following 14 days of continuous immersion in de-ionized water it was found that blocks treated with moderate and above concentrations of a preservative gave no problems, but those b...
R S Smith
Permanence of permethrin and bifenthrin in framing timbers subjected to hazard class 3 exposure
2005 - IRG/WP 05-30383
End-sealed Pinus radiata specimens measuring 235 x 90 x 35 mm were treated using a modified Lowry schedule with permethrin or bifenthrin in white spirit to Hazard Class 2 (H2) retentions. After conditioning, the specimens were exposed at 45o on north facing racks near Melbourne (Australia). Samples of the specimens were taken before installation, and after three and six months exposure. Analyses o...
A C Hunt, D G Humphrey, R Wearne, L J Cookson
Aspects of the fungal degradation of quaternary ammonium compounds in liquid culture
1997 - IRG/WP 97-30160
Didecyldimethylammonium chloride (DDAC) is a quaternary ammonium compound (QAC) that has found use as an anti-sapstain preservative for the transportation of softwood lumber from Canada to overseas markets. However, its use is limited by the knowledge that certain mould fungi seem capable of degrading it. The aim of this research was to gain knowledge about the fungal degradation of DDAC. The effe...
J W Dubois, J N R Ruddick
Immuno-electron microscopic localization of extracellular metabolites in spruce wood decayed by brown-rot fungus Postia placenta
1990 - IRG/WP 1441
Degradation by Postia placenta in spruce and birch wood was shown to occur not only in the wood cell wall but also in the middle lamellae region. Middle lamellae was often found to be degraded along the centerline so that cells could separate along this line. Extracellular membrane structures were found surrounding the hyphae and this matrix labelled positively with antisera produced to Postia pla...
Y S Kim, B Goodell, J Jellison
Respiration measurement of dry-rot
1995 - IRG/WP 95-10095
Methods for measuring the production of carbondioxide from wood infected with the dry-rot fungus were evaluated. By enclosing whole wood blocks and measuring the concentration of gas in the headspace by gas chromatography, an exponential increase in the concentration of CO2 was observed for at least 2 months. This technique could therefore present a method for evaluating various treatments of dry-...
L Toft
Determination of N-cyclohexyl-diazeniumdioxide (HDO) containing compounds in treated wood using GC-MS
2000 - IRG/WP 00-20201
Beside the biological effectiveness the approval of a chemical wood preservative requires also techniques for the analytical determination of active ingredients in different matrices. Fulfilling of the last requirement is particularly difficult in the case of impregnated timber treated with wood preservatives containing organic compounds. This paper describes a procedure for the determination of t...
P Jüngel, J Wittenzellner, E Melcher
Alternative technologies for wood wastes recycling - Part A: Supercritical extraction of PAH compounds from wood wastes
1998 - IRG/WP 98-50101-18 a
Alternative technologies have been investigated to detoxify treated wood. Two classes of organic compounds are studied. Creosote-treated wood are classified in France as dangerous wood wastes. A conventional incineration could be provided for these wood wastes but the cost of this elimination could be very high (> 2000 FFR/ton). For these reasons, we have tested two kinds of new processes as al...
L Schrive, C Perre, G Labat
Extracellular substance from the white rot basidiomycete Irpex lacteus involved in wood degradation
1992 - IRG/WP 92-1571
Cellulases, phenol oxidase, and a substance that both produced and reduced H2O2 were isolated from cultures containing wood or glucose on which the white-rot fungus Irpex lacteus was growing. The rate of wood degradation by the fungus with different amounts of glucose in the medium was measured. More of the substance that produced and reduced H2O2 was found extracellularly in cultures containing w...
H Tanaka, T Hirano, G Fuse, A Enoki
Investigation of the suitability of silver fir (Abies alba Mill.) for thermal modification
2004 - IRG/WP 04-40275
In this study the suitability of silver fir (Abies alba Mill.) was examined for thermal modification. Comparative experimental investigations were performed with silver fir and Norway spruce (Picea abies Karst.) after thermal treatments. Besides properties, which characterize the quality of heat treatments, like dimensional stability and resistance against fungal attack, strength properties of the...
C Brischke, A O Rapp
Premature failure of CCA treated vineyard posts from brown rot
1993 - IRG/WP 93-10016
A survey of CCA (AWPA Type C) treated posts used as grape vine trellis supports, to determine the extent and type of decay was carried out at a terraced vineyard in the Hawkes Bay region of the North Island of New Zealand. Of 357 posts examined out of a total of 970 in the vineyard, 47% had moderate to severe decay or had failed, 20% had established decay, 10% had a trace of decay and 23% had no s...
R N Wakeling, A P Singh
Relationship between degradation of wood, cellulose or lignin-related compounds and production of hydroxyl radical or accumulation of oxalic acid in cultures of brown-rot fungi
1994 - IRG/WP 94-10062
The degradation activities of brown rot fungi against wood, cellulose, and lignin-related compounds were measured in cultures containing glucose or wood as a carbon source. Also the activities of one-electron oxidation and hydroxyl radical production and the amount of oxalic acid present in the cultures were measured. The degradation activities of the fungi against wood, crystalline cellulose and ...
S Itakura, T Hirano, H Tanaka, A Enoki
Durability aspects of (hydro)thermal treated wood
2000 - IRG/WP 00-40160
Samples of several wood species were treated in a two steps process, subsequently hydrothermal and dry heat-treated, by the so-called PLATO-process and analysed for their resistance against fungal attack. Both PLATO-treated and dry heat-treated specimen were prepared and analysed, in order to study the influence of moisture during hydrothermal treatment of wood. The resistance against all of the s...
B F Tjeerdsma, M Stevens, H Militz
The role of oxidation in wood degradation by brown-rot fung
1992 - IRG/WP 92-1562
Brown-rot fungi are suggested to degrade cellulose by oxidation with hydrogen radicalsformed eg. in the conversion of hydrogen peroxide in the Fenton type reactions. The stuctural changes in the holocellulose in wood induced by Fenton's reaction on wood components are very similar to those caused by brown-rot fungi. In this work the effect of the Fenton reaction on wood components was stu...
A-C Ritschkoff, J Pere, J Buchert, L Viikari
Study of the degradation caused by micro-organisms in Pinus sp. waterlogged wood
1989 - IRG/WP 1411
So far, the different Centers are trying the restoration and the conservation of wood structures, coming from subaquatic archeological deposits, with interest from the historic - artistic point of view. The main objective of this paper has been the determination of the decay level of Pinus sp. wood coming from a roman ship (approximately 2000 years old), where we have analyzed their physical prope...
M T De Troya, M C Escorial, J Garcia, A Cabanas
Effect of some resin treatments on fungal degradation reactions
1999 - IRG/WP 99-10318
The effect of impregnation of wood with vegetable oil, tall oil and two water soluble on fungal degradation reactions was assessed by hydrolysis and enzyme activity measurements. The experiments were carried out by using isolated enzyme preparations and a living brown-rot fungus Poria placenta. The results indicate that the inhibitory effect of treatments was clearly directec towards the enzymatic...
A-C Ritschkoff, M Rättö, A J Nurmi, H Kokko, A O Rapp, H Militz
Resistance of acetylated wood to biological degradation. Evaluation of field test
1997 - IRG/WP 97-30139
Acetylated wood samples were tested in ground contact (stake test) at two test fields, one in Simlångsdalen, Sweden, and one in Viikki, Finland, according to European standard EN 252. The test samples were inspected annually and their condition was compared with that of untreated controls and of samples treated with two reference CCA preservatives. The use of untreated controls and preservative t...
P Larsson Brelid, R Simonson, Ö Bergman
The identification of organic compounds in wood using thermal desorption GC-MS - possibilities and limitations
2001 - IRG/WP 01-20224
There is a clear need for the analytical characterisation and identification of organic compounds and their derivatives in different phases especially in timber. In this context the paper describes a rapid and powerful gas chromatographic method for the determination of insecticides, biocides and "other" organic substances in treated and/or modified wood. The main advantage of this procedure is th...
P Jüngel, E Melcher
Differences in pH, electrical resistance, cation composition and NIR spectra of red spruce wood during early stages of brown rot degradation
2002 - IRG/WP 02-10449
Red spruce sapwood was exposed to degradation by the brown rot fungi Coniophora puteana, Postia placenta, Gloeophyllum trabeum and Serpula lacrymans for 0, 1, 2 or 3 weeks using a modified soil block assay design. Average weight losses over time ranged from 0-8.9% during this time period. Detectable changes in pH, electrical resistance and cation compostion were observed in the wood as early as 1 ...
J Jellison, S Kelley, B Goodell, D Hui, A Ostrofsky
Cytoplasmic and extracellular localization of manganese II dependent peroxidase(s) in white rot fungi during degradation of woody materials
1989 - IRG/WP 1416
The manner by which lignin is degraded in-situ in natural substrates by white rot fungi still remains a controversial issue particularly the distribution and role(s) played by lignin degrading enzymes (i.e. manganese II peroxidase and lignin peroxidase). In the present study, use was made of anti-manganese II peroxidase and immunolabelling techniques in conjunction with transmission electron micro...
G F Daniel, B Pettersson, T Nilsson, J Volc
Influences of the hydro-thermal treatment on physical properties of beech wood (Fagus orientalis)
2005 - IRG/WP 05-40303
Influences of the hydro-thermal treatment on physical properties of beech wood were studied. Wood specimens (2×2×2cm) were treated in two steps. At first step, samples were treated at 160,180 & 200ºC for 4, 5 & 6 hours. At second step, treated samples were cured based on their first step treatment temperatures (160,180 & 200ºC) for 16 hours. The treated samples were soaked in water...
B Mohebby, I Sanaei
Microbial decay in an extremely durable Malaysian hardwood Belian (Eusideroxylon zwageri) - an overview
1997 - IRG/WP 97-10216
The heartwood of Belian (Eusideroxylon zwageri) is highly regarded among the naturally durable Malaysian hardwoods, and is therefore a choice timber for soilcontact use in the humid tropics such as untreated telecommunication poles, fence posts and railway sleepers. The high microbial resistance of the wood is evidenced by the mere superficial degradation observed in some pole samples after 20 yea...
A H H Wong, A P Singh
Assessing the importance of degradation mechanisms on the loss of effectiveness of wood preservatives
2000 - IRG/WP 00-20193
Accelerated ageing systems developed for application to samples in the laboratory prior to biological tests, should reflect those natural deterioration processes that are likely to occur in the hazard classes defined in EN 335-1. Losses through evaporation or the effects of leaching have been recognised, however their importance, relative to other mechanisms has not been quantified. Degradation me...
E D Suttie, R J Orsler, T Dearling
Thermal modification of non-durable wood species 2. Improved wood properties of thermal treated wood
1998 - IRG/WP 98-40124
Properties of wood treated in a new heat-treatment process called the PLATO-process have been studied. Several wood species have been treated using this new thermal modification process using a range of process conditions (mainly time and temperature). In this study the characteristics of the treated wood were determined using samples from whole planks treated on pilot plant scale. The modified ch...
B F Tjeerdsma, M J Boonstra, H Militz
Bacterial degradation of Pinus radiata compression wood
1996 - IRG/WP 96-10153
An inspection of twelve year old, CCA-treated Pinus radiata wood from an industrial cooling tower showed extensive surface decay of wood. Electron microscopic examination of decaying compression wood indicated that compression wood cells were attacked exclusively by bacteria, which were of erosion and tunnelling types. As compared to the normal wood, compression wood appeared to be more resistance...
A P Singh, R N Wakeling