Your search resulted in 303 documents. Displaying 25 entries per page.
Correlation between changes in colour and chemical composition during photo-degradation of wood surfaces
2005 - IRG/WP 05-40301
Changes in colour of wood (yellowing) during photo degradation or weathering reflect chemical changes in wood. Therefore, the relationship between changes in chemical composition and CIELAB colour parameters is very important to characterize photodegradation of lignocellulosic surfaces. In this study, the changes in chemical composition and yellowing due to photo-degradation was studied by expos...
K K Pandey
Wood-based composites exposed to fungal degradation: Laboratory results
2001 - IRG/WP 01-40215
Oriented strandboard (OSB) and laminated veneer lumber (LVL) are widely used as residential construction materials. The durability of OSB and LVL against biological degradation has not been studied comprehensively. The objective of this research was to investigate the durability of OSB and LVL when exposed to wood decay fungi. Fourteen brown-rot and eight white-rot wood decay fungi were screened f...
V W Yang, B Illman, L A Ferge, R J Ross
The multi-phase pressure (MPP) process. One stage CCA treatment and accelerated fixation process
- Concepts proved by repetitive pilot plant treatments
1997 - IRG/WP 97-40079
Twenty-four charges of radiate pine roundwood or sawn timber were treated using the MPP Process and hot CCA solution. Treated timber met the CCA retention and penetration requirements of the NZ Timber Preservation Council for Hazard Classes H3 to H5. The objectives of the trials were: (1) To "stress" CCA solution by repetitive heating, treating and cooling to determine its stability in the process...
A J Pendlebury, J A Drysdale, K Nasheri, H Pearson, M E Hedley
A study on the pressure impregnation of Eucalyptus globulus fence posts with CCA preservatives. Part 1
1988 - IRG/WP 3470
This paper describes the impregnation with CCA preservatives by full-cell process of Eucalyptus globulus fence-posts. Several treatments were made for different times of initial vacuum and treating pressure, with fence-posts from two coppice plantations (1st and 2nd rotations), assembled into three diameter classes: small, medium, large. The results concerning the absorption and lateral penetratio...
D De Sousa Castro Reimão, L Nunes
Molecular analysis of the basidiomycete Coniophora puteana
1992 - IRG/WP 92-1534
Sodium dodecylsulphate polyacrylamide gel electrophoresis and Western Blotting, using a polyclonal antiserum produced against a whole cell extract of Coniophora puteana, were used to analyse the major proteins and antigens of the wet rot organism Coniophora puteana. The macromolecule profiles of this organism were different from other members of the Coniophora genus and from a set of unrelated org...
H E McDowell, D Button, J W Palfreyman
The fungal degradation of quaternary ammonium compounds in wood
1998 - IRG/WP 98-10263
This work focuses on the biodegradation of didecyldimethylammonium chloride (DDAC) by the mould fungus Gliocladium roseum within a woody matrix. Three sawdust types, distinguished by their treatment and amount of DDAC retained, were inoculated with the fungus and their DDAC loss was measured over 11 weeks. The rates of degradation varied depending on the sawdust; however, a significant loss of DDA...
J W Dubois, J N R Ruddick
Investigation of temperature effect on fixation of Celcure preservative (ACC) in beech (Fagus orientalis)
2001 - IRG/WP 01-40200
In this research, the fixation speed of Celcure 2% (ACC) preservative salt, under temperature of 17°C, 27°C and 50°C, on intact and stained wood specimens of beech was investigated. For this purpose, blocks of wood with 5x5x7 cm dimensions were prepared and saturated with 2% ACC concentration by full-cell process. The specimens were put in three incubators at the above-mentioned temperatures. F...
A Karimi, M Ghorbani
Effect of angle of exposure on degradation of radiata pine during weathering trials
1988 - IRG/WP 2301
The importance of angle of exposure on the degree of weathering of materials has not been adequately resolved. In conventional tests, specimens are exposed at an angle of 45° facing the equator, but more recently experiments on polymeric materials have suggested that an angle of 0° may be preferable since this angle maximises levels of received ultra-violet radiation. In this paper the degradati...
P D Evans
The degradation of wood surfaces by water
1984 - IRG/WP 3289
Thin radial/longitudinal sections (~100 µ) of Scots Pine (Pinus sylvestris) and lime (Tilia vulgaris), were exposed to deionised water over the temperature range 25-65°C. Losses in wet tensile strength and toughness occurred rapidly at temperatures from about 50°C upwards. After about 2 months' exposure pine lost some 10-30% of its tensile strength and 20-60% of its toughness. For lime...
W B Banks, P D Evans
Distinguishing isolates of Aureobasidium on the basis of their ability to utilise lignin breakdown products as a sole carbon source
1996 - IRG/WP 96-10151
Wild isolates of Aureobasidium were obtained by dilution plating from a ca 20 year old painted pine window frame. Four isolates were obtained from the paint/wood interface region and four isolated from regions deep in the wood. The isolates were then used to inoculate liquid cultures containing ferulic acid, a lignin breakdown product, present as the sole carbon source. Ability of the isolates to ...
M W Schoeman, D J Dickinson
Microscopic characteristics of microbial attacks of CCA-treated radiata pine wood
1993 - IRG/WP 93-10011
Light and electron microscopic observations were made of CCA-treated radiata timbers, which had been placed in service in a vineyard soil as supporting poles and as part of a house pile, to determine the cause of their deterioration. The house pile had failed in service after between 9 and 13 years and was of particular interest because decay was more severe in deeper regions than at the surface a...
A P Singh, R N Wakeling
Effects of alkali treatment on some mechanical and chemical properties of creosote treated oaks
1991 - IRG/WP 2366
To date, there is a lack of information on the effects of chemical treatment on the performance of creosote preservative treated oak sleepers. This factorial experiment was designed to analyze three main effects: species (Quercus alba and Quercus rubra) creosote treatment (treated and untreated), and alkali (NaOH) soaking (0, 1, and 10 percent). The modulus of elasticity (MOE) and fiber stress at ...
P Chow, A J Reinschmidt, E J Barenberg, L C Chang
Biodegradation of wood in wet environments: A review
1997 - IRG/WP 97-10217
Wood in wet environments is attacked and degraded by soft rot fungi and erosion and tunnelling bacteria, which are more tolerant to high moisture and reduced oxygen conditions than basidiomycetes, such as white and brown rot fungi. Since basidiomycetes are normally more aggressive and can degrade wood faster than soft rot fungi and bacteria wood in wet environments can survive longer. In fact, arc...
A P Singh, Yoon Soo Kim
Effect of treating process on efficacy of CCA in a laboratory decay test
1990 - IRG/WP 3628
Test samples of Pinus radiata sapwood measuring 40x40x500 mm³ were treated with a range of concentrations of the copper-chrome-arsenate (CCA) formulation "Tanalith C" using Rueping (empty cell), Lowry (empty cell) and Bethell (full cell) treatment processes. Samples were then reduced to 40x40x7 mm³ test blocks and exposed to the decay fungus Coniophora puteana using an agar/block technique. Repl...
M E Hedley, K Nasheri, J G Van der Waals
Production of exraxellular hydrogen peroxide and oxalic acid by brown-rot fungus Poria placenta
1995 - IRG/WP 95-10112
Hydrogen peroxide and oxalic acid have been suggested to be essential in the degradation of wood carbohydrates by brown-rot fungi. Hydrogen peroxide has been suggested to be one of the diffusible low molecular weight agents produced by brown-rot fungi for the degradation of wood carbohydrates by generating highly active radicals. The production of hydrogen peroxide and oxalic acid by Poria placent...
A-C Ritschkoff, M Rättö, J Buchert, L Viikari
Degradation of lignin model compounds with coordinated copper in the presence of peroxide
1998 - IRG/WP 98-10282
A novel diffusible system capable of decomposing lignin model compounds with copper, coordinators and peroxides has been proposed. When pyridine was used as a copper coordinator, two synthetic dyes, Poly-R and RBBR were intensively decolorized with Cu(II) and H2O2 in aqueous solutions at room temperature. Although reactions with Cu(II) and H2O2 produce a strong oxidant, hydroxyl radical, via a Fen...
K Koller, K Messner, T Watanabe
A study on the pressure impregnation of Eucalyptus globulus fence-posts with CCA preservatives. Part 2
1989 - IRG/WP 3514
This paper describes the second part of a study on pressure impregnation of Eucalyptus globulus fence-posts with CCA preservatives presented at the IRG 19th Meeting. Fence-posts of three diameter classes, were treated, considering only one treatment schedule. The results show possibility of vacuum-pressure impregnation of blue gum fence-posts, with diameter less than 9 cm, though mainly by longitu...
L Nunes, D De Sousa Castro Reimão
The rôle of lignin in the nutrition of several Australian termites
1983 - IRG/WP 1191
The ability of Nasutitermes exitiosus (Hill), Coptotermes acinaciformis (Frogatt), Coptotermes lacteus (Froggatt) and Mastotermes darwiniensis (Froggatt) to degrade 14C-lignin preparations was examined. The lower termites were unable to degrade lignin. Nasutitermes exitiosus was able to cause a 5-8% degradation of hardwood lignins and a synthetic lignin. It failed to degrade the lignin of Pinus ra...
L J Cookson
A technique for the rapid assessment of wood surface degradation during weathering
1987 - IRG/WP 2281
Radiate pine (Pinus radiata D. Don) sapwood samples taken from four trees were converted into thin strips 100 x 10 x 0.085 (85 µm) mm³, (longitudinal x radial x tangential) in size and exposed in preweighed hatches to the weather inclined at 45° facing equatorially for 10, 20, 40, 60, 80 and 100 days. Significant (P < 0.001) weight losses occurred with time over the exposure period. Differen...
P D Evans, D Abbott, S Thein
A novel guide for the determination of the physical properties of wood including kiln drying and full-cell preservative treatment
2004 - IRG/WP 04-20298
An ideal flow chart for the sequential experimental determination of a range of physical properties relevant to wood drying and subsequent preservation was designed as a novel guide to assist wood scientists. In this manner, data assembly and experimental processing are shown. This was designed according to experience and published literature. Aspects emphasised in this review were the physical p...
I Usta, M D C Hale
Trial to determine a suitable schedule for radial and longitudinal treatment of plug samples by comparison of changes in the fluid retention and the treated area
2001 - IRG/WP 01-40211
A full-cell process was carried out using different treatment schedules for radial and longitudinal samples because of the anisotrophy of flow. When timbers are impregnated with preservatives much better penetrations are obtained via the end grain than laterally (across the grain). Therefore, suitable schedules for radial and longitudinal flow directions were determined in an trial experiment usin...
I Usta
Studies of the ray parenchyma cell ends on the radial flow of Sitka spruce (Picea sitchensis)
2000 - IRG/WP 00-40164
It is widely accepted that either ray tracheids or ray parenchyma cells offer the major flow pathways radially for the impregnation of softwood with preservative chemicals. It is now generally recognised that, if radial flow does occur through ray parenchyma cells, the cross-field pits play a dominating role for the liquid movement in the radial direction. In this case, the radial flow of fluid is...
I Usta
The degradation of wood by metal fastenings and fittings
1972 - IRG/WP 302
As well as the hazards of biological decay, timber used in boat building is subject to the effects of chemical decay associated with the corrosion of metallic fastenings. The title has been deliberately chosen to emphasize that in wooden construction the troubles are not just those of corrosion of the fastenings, but also the destructive secondary effects on the wood caused by the products of the ...
L C Pinion
Bacteria are important degraders of cooling tower timbers: New Zealand experience
1995 - IRG/WP 95-10128
Microscopic examinations of CCA-treated Pinus radiata timbers in industrial cooling towers in New Zealand showed bacteria and soft rot fungi to be primarily responsible for the decay of these timbers. Of these micro-organisms, erosion bacteria appeared to be most widespread, attacking wood cell walls independently as well as together with tunnelling bacteria and soft rot fungi. Tunnelling bacteria...
A P Singh, R N Wakeling
New approaches to practical evaluation method of bio-degradation of wooden construction - Non-destructive detection of defects using radar technique
2000 - IRG/WP 00-20214
There have been a number of researches and developments on the techniques and apparatus for the nondestructive evaluation of the biological deterioration in wood and wooden constructions, such as decay or insect attack in house, public buildings or in historically important architectures. As for the detection of the decay in wood, techniques using sound in audible or in ultrasonic frequency ranges...
Y Fujii, Y Komatsu, Y Yanase, S Okumura, Y Imamura, M Tarumi, H Takiuchi, A Inai