Your search resulted in 287 documents. Displaying 25 entries per page.
The Effect on Biological and Moisture Resistance of Epichlorohydrin Chemically Modified Wood
2002 - IRG/WP 02-40224
Southern pine solid wood and fiber were chemically modified with epichlorohydrin to help in understanding the role of moisture in the mechanism of biological effectiveness of chemically modified wood. The solid wood had weight gains from 11% to 34%, while the fiber had weight gains from 9% to 75%. After modification, part of the specimens were water leached
for 2 weeks or extracted for 2 hours ...
R E Ibach, B-G Lee
The nature of osmiophilic particles and their distribution during different stages of brown and white rot decay
1983 - IRG/WP 1213
The distribution of osmiophilic particles during the course of brown and white rot decay was investigated by applying transmission electron microscopic (TEM) methods. It was found that it correlates with the brown and white rot pattern.The osmiophilic particles are produced by the fungus and are supposed to be wood rotting enzymes....
K Messner, H Stachelberger
Preservative treatment of rubber wood (Hevea brasiliensis) to increase its service life
2005 - IRG/WP 05-40320
Rubber wood (Hevea brasiliensis) possess excellent properties for interior designing, wood working and furniture making. But it is very much susceptible to sap stain and mould fungi which decreases the service life. For profitable uses , it is necessary to increase the service life of rubber wood. To protect the rubber wood from wood degrading agents, the sawn timber were treated with Borax – b...
K Akhter
Screening of modified linseed oils on their applicability in wood protection
2004 - IRG/WP 04-30346
In this study modified linseed oils, rape oil and three waxes were screened on their efficacy as wood protecting agents. By testing all products when impregnated with high retentions in Scots Pine sapwood on water repellence qualities, additionally an accelerated weathering test, drying quality, accelerated brown rot and blue stain test, an indication is formed of the capability of these products ...
A Treu, J Lückers, H Militz
Hyphal tunnelling of belian (Eusideroxylon zwageri) wood cell walls
1996 - IRG/WP 96-10152
Belian (Eusideroxylon zwageri) is highly regarded among the naturally durable Malaysian hardwoods. Visual inspections at the groundline of belian transmission poles from Sarawak, Malaysia, showed only surface decay of wood after 20 years in service. The cause of decay in belian was investigated by light and transmission electron microscopy. Light microscopy of transverse sections of surface tissue...
A P Singh, A H H Wong
Diffusion and interaction of components of water-borne preservatives in the wood cell wall
1988 - IRG/WP 3474
This study investigates the rates of diffusion and ultimate distributions of copper and arsenate components of wood preservatives in wood cell walls following vacuum treatment. Adsorption studies of copper on red pine (Pinus resinosa) and trembling aspen (Populus tremuloides) wood confirm the importance of cation exchange reactions on the ultimate distribution of copper in the wood substance and i...
P A Cooper
Evidence for actinomycete degradation of wood cell walls
1990 - IRG/WP 1444
Several unique patterns of degradation occurring in wood cell walls have been observed in wooden stakes inserted in unsterile soil in the laboratory. Some of the patterns have also been observed in coniferous wood taken from forest floors. All the observed attack types occur within wood cell walls, mainly within the S2 layer. Attack is characterised by channels of varying diameter or small fusifor...
T Nilsson, G F Daniel, S L Bardage
On the nature of the tertiary wall in wood cells. Summary of lecture given at 9th Annual Meeting, Noordwijk-aan-Zee, Holland
1977 - IRG/WP 169
During recent discussions on the possible causes of failure of treated hardwood species by soft rot fungi, the uneven micro distribution of toxic components was found to be of importance; this might be attributed to a restricted diffusion of the preservative from the cell lumina into the cell wall.·In this context, the nature of the tertiary wall as the inner lining of wood cells merits special a...
W Liese
Ingestion of wood-degrading micro-organisms
1991 - IRG/WP 4169
An ultrastructural study was carried out on the digestive tract contents of Limnoria lignorum, frass, gallery walls and surface structures of the animals. The purpose of the study was to determine whether wood-degrading bacteria, fungi and other microbes and/or wood degraded by these microbes were present in gut regions and therefore could provide indirectly a nutritional source for Limnoria. Both...
G F Daniel, S M Cragg, T Nilsson
Immunolocalization of extracellular metabolites from Poria placenta
1988 - IRG/WP 1361
Polyclonal antisera produced to Poria placenta extracellular metabolites was used in immuno-fluoresence microscopy and immuno-gold TEM studies. In the fluorescence work, labelling of Poria placenta hyphae in wet fixed wood material was observed but not in infected wood which was oven dried prior to sectioning and immunolabelling. TEM studies provided better resolution, with gold labelling detected...
B Goodell, G F Daniel, J Jellison, T Nilsson
Comparison of thermally modified wood originating from four industrial scale processes – durability
2002 - IRG/WP 02-40229
This study examined the differences in biological wood properties of heat treated wood originating from four different European industrial heat treatment plants. The manufacturers of heat treated material were: PLATO Hout B.V./Netherlands, Thermo Wood/Finland, New Option Wood/France and Menz Holz/Germany where Oil-Heat treated Wood (OHT) is produced.
The results of miniblock tests with basidiomyc...
C R Welzbacher, A O Rapp
Extracellular osmiophilic particles in connection with brown rot and white rot
1982 - IRG/WP 1157
The way of attack on Pine woodblocks of two brown-rot fungi (Fomitopsis pinicola, Coniophora puteana) differing in their cellulase activities, and one white-rot fungus (Trametes hirsuta) has been investigated by transmission electron microscopy. Even at early stages of decay, osmiophilic particles were found with all the fungi investigated. In the brown-rotted wood, the osmiophilic particles occur...
K Messner, H Stachelberger
A quantitative weathering study of wood surfaces modified by chromium VI and iron III compounds
1989 - IRG/WP 2330
Thin veneers of Pinus radiata were treated with dilute aqueous solutions of chromium VI and iron III compounds and exposed to natural weathering for 35 days. Zero-span tensile strength and weight losses of treated veneers were compared with losses observed in untreated specimens In a study designed to demonstrate the applicability of strength and weight loss measurements to the rapid quantitative ...
P D Evans, K J Schmalzl
Cavitation bacteria
1984 - IRG/WP 1235
A form of bacterial wood degradation is described. The term "cavitation bacteria" has been coined in order to describe the discrete cavities that are formed within the wood cell walls. The bacteria observed within the cavities appeared to be polymorphic with rounded as well as filamentous forms recognised. TEM studies suggest that the bacteria produce diffusable wood-degrading enzymes. Cavitation ...
T Nilsson, A P Singh
Bending strength of heat-treated spruce and pine timber
2002 - IRG/WP 02-40242
Heat-treatment of spruce (Picea abies) and pine (Pinus sylvestris) beams (45 x 145 mm) gave a reduction in bending strength of approximately 50%. The bending stiffness (modulus of elasticity) only decreased by 3.5%. Tests were carried out according to EN 408. Another effect of the heat-treatment was increased variation in bending strength. The 5th percentile value of the bending strength, the so c...
C Bengtsson, J Jermer, F Brem
The development of soft rot decay in bamboo fibres
1992 - IRG/WP 92-1572
The development of decay by soft rot fungus Chaetomium globosum was investigated in young and mature culms of bamboo Phyllostachys virideglaucescens. Soft rot decay was influenced both quantitatively and qualitatively by the differing levels of lignification in the material. Weight loss was significantly greater in the younger culm compared with the older, more heavily lignified culm. The distribu...
O Sulaiman, R J Murphy
Characteristics of thermally modified wood in vacuum
2004 - IRG/WP 04-40287
In commercial thermal wood modification processes nitrogen, steam or oil has been used for the reduction of oxygen content in the reactor atmosphere. In present study no special heating medium, but an initial vacuuming step has been used for this purpose. Mass loss, resistance to fungal decay, dimensional stability, bending strength and modulus of elasticity of heat treated wood were evaluated and...
G Rep, F Pohleven, B Bucar
Bacterial degradation of wood cell wall: A review of degradation patterns
1990 - IRG/WP 1460
Information from bacterial degradation studies of 60's and 70's was reviewed by Nilsson in 1982. The application of electron microscopy to this area in recent years has provided much useful information and has eliminated earlier scepticism among workers about the ability of bacteria to degrade lignified wood cell walls. Studies using transmission electron microscopy together with...
A P Singh, J A Butcher
Chemically modified tannin and tannin-copper complexes as preservatives for wood
2001 - IRG/WP 01-30271
The efficacy of Mimosa tannin, chemically modified tannin, and tannin-copper complexes as wood preservatives was studied. When the tannin-ammonia-CuCl2 solutions were impregnated into wood specimens in a one-step procedure, a large quantity of the tannin-copper complex was fixed in the specimens. Little of the complex was leached from specimens by a weathering treatment, and these specimens showed...
H Yamaguchi
Preliminary pole treatment trials with chlorothalonil in hydrocarbon solvent
1994 - IRG/WP 94-40027
A series of 460-mm long, end-sealed southern pine pole stubs were treated with chlorothalonil in hydrocarbon solvent. Over sixty sections were treated using various combinations of initial seasoning (kiln-drying, steam-conditioning), treating temperature (ambient, 200°F), initial air pressure, and final conditioning (steam flash + vacuum, expansion bath + vacuum, steam distillation + vacuum). Dis...
H M Barnes
Utilisation of carbohydrates by stain fungi in agar culture
1998 - IRG/WP 98-10248
Stain fungi are often defined by their ability to utilise the starch and free sugars found in ray parenchyma cells, and their inability to utilise other wood constituents. However, several species of stain fungi produce bore holes in wood cell walls. This suggests that enzymatic activity capable of degrading structural polysaccharides and/or lignin is associated with the growth of the appressorium...
J Snow, P Vinden, S M Read
A field evaluation of modified and unmodified alkylammonium compounds
1987 - IRG/WP 3436
Laboratory soil block studies of alkylammonium compounds (AAC's) at Forintek and other research establishments have shown that they can prevent decay by standard wood-destroying fungi. Their performance in field tests, however, has been disappointing. Following investigation of possible causes for this poor field performance, stakes treated with modified AAC's were installed at W...
J N R Ruddick
Degradation of woods by obligately anaerobic fungi
1990 - IRG/WP 1452
Little is known about the processes occurring during the degradation of wood by obligately anaerobic fungi. When woods from a range of hardwood species were incubated for 11 days with a strain of the Chytrid Neocallimastix frontalis many of the woods were measurably fermented; Fagus sylvatica (23%) was the most highly degraded. Microscopic examination of Populus tremuloides wood after incubation w...
K N Joblin, G E Naylor
A Novel Type of Multiple Cavity Attack in Wood Cell Walls of Heat-treated Timber Exposed in Seawater – Preliminary Observations
2004 - IRG/WP 04-10523
Samples of untreated and heat-treated Norway spruce and Douglas fir were submerged in Langstone Harbour, Portsmouth for 4 years at a depth of ca. 0.3 metres. The heat-treated samples had been prepared using the Plato process. Samples were initially assessed for the severity of marine borer damage and were then examined microscopically for evidence of microbial decay. Longitudinal and transverse wo...
R A Eaton, C Björdal, T Nilsson
Exclusion of anions from the wood cell wall
1991 - IRG/WP 3661
Anionic components of wood preservatives and fire retardants such, as arsenates and phosphates, equilibrate at much lower concentrations in the cell wall bound water than in the free solution in the cell lumens. A degree of anion exclusion is expected in wood, due to the Donnan membrane effect. Fixed anions in the wood cell wall, produced by pH-dependent dissociation of the weak acid groups in woo...
P A Cooper