Your search resulted in 82 documents. Displaying 25 entries per page.
Development of markers to predict decay durability of heat treated wood
2010 - IRG/WP 10-40496
Effect of heat treatment temperature on elemental composition of Scots pine sapwood (Pinus sylvestris) has been investigated in the range of temperatures between 220 and 250°C. Results revealed an important increase of carbon content, while oxygen content significantly decreases. Independently of the heat treatment temperature, elemental composition is strongly correlated with the mass losses due to thermal degradations. Carbons content as well as O/C ratio seem to represent valuable markers to estimate wood degradation after heat treatment. Heat treated specimens were exposed to fungal decay using the brown rot fungus Poria placenta and the weight losses due to fungal degradation were determined. Correlations between weight losses recorded after fungal exposure and elemental composition indicated that carbon content or O/C ratio can be used to predict wood durability conferred by heat treatment allowing to envisage the development of a proper method to evaluate the quality of heat treated wood and predict its durability. These results also confirm that chemical modifications of wood cell wall polymers are the main factors responsible for wood durability improvement against fungal decay after heat treatment.
Ž Šušteršic, A Mohareb, M Chaouch, M Pétrissans, M Petric, P Gérardin
Sequestration of copper ions by the extracellular mucilaginous material (ECMM) of two wood rotting basidiomycetes
2004 - IRG/WP 04-10533
The radial growth rate of colonies originating from either whole or ECMM-free inocula of Coriolus versicolor was investigated. The presence of ECMM allowed colonies to maintain higher growth rates than those form ECMM-free inocula up to 2 mM CuSO4 in the medium. The ECMM of C. versicolor and G. trabeum was able to reduce the diffusion of copper ions in solution. The ‘raw’ ECMM of both fungi had a greater ability to reduce the diffusion of copper ions than ECMM which had been subject to dialysis to remove soluble, low molecular weight components. The ‘insoluble’ fraction of ECMM for both species was more effective than the ‘soluble’ fraction at reducing the diffusion of copper ions. It is concluded that ECMM confers some protection to hyphae against the toxic effects of copper ions on growth in vivo and that this due to the binding of copper ions to both the polysaccharide and to low molecular weight components of the ECMM
D Vesentini, D J Dickinson, R J Murphy
Mould resistance of lignocellulosic material treated with some protective chemicals
1984 - IRG/WP 3294
Effectiveness of preserving lignocellulosic material against moulding by treatement with water solutions of commercial wood preservatives and mixtures of various inorganic salts was investigated and compared with the effectivenes of sodium pentachlorophenoxide and boric acid.
Contribution to the testing of wood based board material
1982 - IRG/WP 2176
R G Lea
Review of remediation methods of sites contaminated by wood preservatives - testing of filter material for use in permeable barrier technology
1999 - IRG/WP 99-50141
Several treatment methods are currently available for treatment of contaminated sites. Soil and water can be treated by immobilisation, separation or destruction of contaminants. It has been common to use intensive treatment methods starting with soil excavation to reach strict purification goals. However, technical and financial reasons make it difficult to reach the desired treatment criteria. As a result, alternative treatment methods are now being allowed. Less intensive in situ methods are being developed, such as natural attenuation, phytoremediation and permeable barriers. A permeable barrier is a passive treatment method for contaminated groundwater. A study was conducted to test various barrier materials for filtering creosote contaminated groundwater. Peat, compost, bark, sewage sludge and sewage sludge pellets were tested out for sorption of phenol, 2-methylphenol and 2,4-dimethylphenol. Peat and compost showed best sorption efficiency. Peat and compost were mixed with sand in various fractions to see if sand can be used to improve hydraulic properties of the filter material.
G Rasmussen, H Iversen, S Andersen
Evaluation of some polyurethanes as protective marine coatings for wood
1985 - IRG/WP 4115
Several polyurethane formulations were evaluated in the marine environment as possible replacements for Irish felt used on U.S. Navy minesweepers as a marine borer barrier between the main wooden hull and an outer, wooden sheathing which covers it. Pine panels coated with the candidate materials were tightly juxtaposed with untreated pine baitwood to simulate the hull/sheathing configuration, the baitwood serving as a substrate in which settling borer larve could metamorphose. Primarily, the purpose was to see if adult borers could perforate the coatings at the coating/wood interface and enter the wood beneath, however the ability of these coatings to survive in sea water for an extended time was also noted. Panels were exposed from 48 to 89 months in Panamanian waters. Teredinids were able to perforate four of the coatings from the baitwood; pholads were able to perforate all of the coatings with ease and were the major cause of coating damage at the coating/baitwood interface. None of the coating surfaces exposed directly to the sea water were damaged by teredinids or pholads, however the coatings on some of the panels were eventually reduced to tatters with large sections of the original specimen missing. This was a result of borer infestation of the underlying wood via prior pholad-induced holes which were uncovered when the panel faces were reversed in the panel/baitwood configuration during the exposure.
J D Bultman, J E Pinto
Radio frequency heating times for sterilization radiata pine solid piles
2017 - IRG/WP 17-40815
In this work was sterilized wood packaging material of radiata pine, stacked as solid piles without stickers, for determining the heating times using radiofrequency treatment. The experiments were performed in a radio frequency semi-industrial equipment. The results showed that the radio frequency heating times increases with wood volume and that radio frequency treatments were faster than conventional vapour heat treatment.
H Esquivel, V Sepúlveda, J Torres, L Salvo, R A Ananías
SEM investigation of the production of extracellular mucilaginous material (ECM) by some wood inhabiting and wood decay fungi when grown in wood
1997 - IRG/WP 97-10193
Previous reports have illustrated the involvement of extracellular mucilage (ECM) in wood decay by Basidiomycetes. Its production is investigated in a range of stain, mould and soft rot fungi in Corsican pine, Scots pine and European beech. Fungi examined were: Chaetomium globosum, Ceratocystis coerulescens, Trichoderma harzianum, Ophiostoma piceae, Mucor sp. and Penicillium. sp. The samples were examined in the frozen hydrated (FH) and freeze dried (FD) conditions using SEM. Most of the fungi tested produced ECM with the amounts produced varying from one fungus to the other. Different morphological forms of the mucilage were observed. ECM produced by C. coerulescens was mostly fibrillar, and interesting morphological forms of the ECM were associated with hyphae of T. harzianum. Small amounts of mucilage were produced by O. piceae and Penicillium sp. Further investigation is necessary on the ECM production in Mucor sp.
A R Abu, D J Dickinson, R J Murphy
Determination of the water sorption properties and preliminary results from field tests above ground of thermally modified material from industrial scale processes
2004 - IRG/WP 04-40279
In this study the differences in moisture behavior and durability above ground of heat treated wood originating from different European industrial heat treatment plants by means of the water sorption properties as well as field tests were examined. The manufacturers of heat treated material were: PLATO Hout B.V./Netherlands, Thermo Wood (Premium wood)/ Finland and Menz Holz/ Germany, where Oil-Heat treated Wood (OHT) is produced. Temporary evaluation of field tests showed a substantially improved resistance against biological attack of the thermally modified material compared to controls. The results of the laboratory tests regarding the determination of the Moisture induced Risk Index (MRI) showed a significantly reduced MRI of heat treated material compared to references. Material from the PLATO process and Oil-Heat treated material revealed significantly lower MRI values than Thermowood. Natural weathering above ground had so far no significant influence on the MRI of thermally modified specimens compared to the initial values.
C R Welzbacher; A O Rapp
Preservative effect of cellulose insulation material against some mould fungi and brown rot fungus Coniophora puteana in pine sapwood
1991 - IRG/WP 1484
The influence of mineral wool and loose-fill cellulose wool on biodeterioration of pine sapwood was studied. The test fungi were mould fungi Aspergillus versicolor, Cladosporium sphaerospermum, Penicillium sp. and Aureobasidium pullullans and brown rot fungus Coniophora puteana. Cellulose wool inhibited the growth of mould fungi on the face of wood contacted with insulation material at RH of 97 and 100%. During 6 months' incubation boron compounds added in cellulose wool diffused into the wood. No growth of brown rot fungus was detected in "treated wood". Mineral wool had no preventive effect on the growth of mould fungi and brown rot fungus Coniophora puteana.
SEM investigation of the production of extracellular mucilaginous material (ECM) by some wood inhabiting and wood decay fungi when grown on inert surfaces
1997 - IRG/WP 97-10194
A range of wood inhabiting and wood decay fungi have been studied for their production of extracellular mucilage when grown on inert surfaces, for comparison with their growth on wood. The species tested were: Coniophora puteana, Coriolus versicolor, Chaetomium globosum, Trichoderma harzianum, Ceratocystis coerulescens, Ophiostoma piceae, Mucor sp. and Penicillium sp. They were grown on plastic meshes, melinex sheets and glass cover slips and were examined in the freeze dried (FD) and frozen hydrated (FH) conditions. For most of the fungi tested, the ECM production was induced upon contact with the inert surface, although the amount of the ECM produced was far less than that produced by the same fungi in wood. The ECM produced by C. puteana and C. versicolor was similar and more extensive, when compared to that produced by the other fungi. ECM was not produced by Mucor sp. and Penicillium sp.
A R Abu, R J Murphy, D J Dickinson
Resistance of wood inorganic material composites against decay fungi and subterranean termites
1996 - IRG/WP 96-40062
Double diffusion process was applied to the treatment of small sound sapwood specimens [20(T) x 20(R) x 10(L) mm³] of Cryptomeria japonica D. Don. The specimens were consecutively dipped in the two kinds of acqueous solutions to form water insoluble deposits within the wood after an expected reaction between the solutes. Following the comparison of deposits formed and treating conditions (temperature and solution concentrations), BaHPO4 as a water insoluble precipitation performed best against decay fungi (Coriolus versicolor and Tyromyces palustris) and subterranean termites (Coptotermes formosanus Shiraki) in the standardized laboratory tests. Addition of boric acid enhanced the performance of the wood inorganic material composites. Relatively low weight percent gain by deposits (<3%) was proved effective in controlling biological deterioration of the treated samples when boric acid was added to the treating solutions
K Tsunoda, T Yoshimura, M Takahashi, S Hirao, H Usui
Invasion and colonisation of bamboo culm material by stain and decay fungi
2002 - IRG/WP 02-10453
Two distinct stages of the fungal infection of bamboo culms can be identified: entry into the culm itself (invasion) and further colonisation by spread within the culm wall tissue. This laboratory study aimed to characterise different invasion strategies of a variety of fungi. Well-known isolates of white- (Coriolus versicolor, Schizophyllum commune), brown- (Coniophora puteana, Gloeophyllum trabeum, Poria placenta), soft-rotting (Chaetomium globosum) and stain fungi (Lasiodiplodia theobromae) were used as test organisms in culm wall material of Moso Bamboo (Phyllostachys edulis). By giving the fungus defined “entrances” into the specimen and by introducing a “baiting” method, routes of entry taken by fungal hyphae during infection of the culm tissue were investigated using light and scanning electron microscopy. he results show clearly that typical bamboo decay fungi such as S. commune and C. globosum can infect the fresh, undamaged culms via the dense outer epidermis if growth conditions are optimal. No part of the culm was identified as a barrier. Small bore holes in the epidermis, caused by penetrating hyphae were identified using scanning electron microscopy. It is proposed that this was the main pathway of entry into the culm tissue.
G Kleist, I Morris, R J Murphy
Effects of cyproconazole and copper sulphate on the length of the hyphal growth unit (HGU) of the white-rot fungus Coriolus versicolor
2003 - IRG/WP 03-10473
Wood decay basidiomycetes have been shown to produce appreciable quantities of extracellular mucilaginous materials (ECMM). The relationship between ECMM and total biomass production has been investigated in the white-rot fungus Coriolus versicolor (CTB 863 A). Differences in the amount of ECMM produced by the fungus proportionally to the total biomass, were observed under a range of physiological conditions, including the presence of biocides. Such differences suggest that stress may have a role in stimulating an increase in the amount of ECMM produced by C. versicolor. The rationale behind this study is that the increase in the proportional amount of ECMM produced by the organism under a range of different stress conditions, may be explained by the hypothesis of the Hyphal Growth Unit length (HGU). The results presented in this paper support the hypothesis that the length of the HGU is strongly related to the environmental conditions. Cyproconazole at 0.1 mmols l-1 in the growth medium, reduced total biomass by approximately 50% and decreased the length of the HGU by approximately 50%. This change in the HGU length reflects a change in the hyphal behaviour to a highly brached mycelial habit. Associated with this was a 100% increase in the proportion of ECMM in relation to the hyphal biomass. Since ECMM is known to be secreted at the tip of actively growing hyphae, it is hypothesised that by adjusting the length of the HGU, filamentous fungi are able to produce a highly branched mycelium, which leads to the production of high levels of ECMM. This could offer protection against adverse environmental conditions, such as the presence of biocides. These results are discussed with regard to the possible role(s) of ECMM in the decay process and its interaction with preservative treatments.
D Vesentini, D J Dickinson, R J Murphy
Wood kiln drying. Simple process of material treament or soft method of preservation? (Le séchage arificiel du bois. Simple opération de traitement du metériau ou méthode douce de préservation?)
1993 - IRG/WP 93-50001-14
Among the processes enabling to extend wood durability, kiln drying can be considered as a treatment and soft preservation method. Dry woods are naturally durable provided they are not subject to important retaking of the moisture. Drying thanks to the application of temperatures from 50 to120°C enable to execute a thermic treatment which kills grubs and mushrooms to ensure a sterilization that can be durable if wood doesn't retake water. Noumerous connections and analogies between drying process and the preservation one enable to conclude that kiln drying is a real operation of wood treatment either curative or to a smaller extent preventive.
Investigation of extracellular mucilaginous material in some wood decay fungi
1996 - IRG/WP 96-10188
The external morphology of the extracellular mucilagenous material (ECM) produced by Coriolus versicolor and Coniophora puteana during colonization of Scots pine and beech was studies using SEM. Specimens were examined in the frozen hydrated, freeze-dried and critical point dried state. All technics produced artefacts but the ECM was best preserved when examined the frozen hydated state. Critical point drying damaged the ECM extensively but was useful in partly explaining its nature. ECM was found to line much of the lumen and coated aerial fungal mycelium. Some morphological patterns in which the ECM and fungal hyphae were involved are also descibed.
A R Abu, D J Dickinson, R J Murphy
Deterioration and preservation of Japanese pampas grass as a roofing material
1991 - IRG/WP 1490
The deterioration and preservation of Japanese pampas grass as a roofing material were investigated. The pith of stem and sheath were more rapidly decomposed. The vessels were the most important pathway of microbial prevalence. Hyphae invaded into the cell wall of fiber and parenchyma, and made the cavities with conical ends. The contacting cell wall of parenchyma in pith with hyphae was decomposed like dissolving. The isolated fungi were mainly microfungi and macrofungi (basidiomycetes) appeared rarely. The strength of stem vigrously decreased by the deterioration. Lignin and 1% alkali extractives increased and polysaccharide decreased in the deteriorated pampas grass. Xylan was decomposed faster than glucan. Structural difference was shown between the deteriorated and undeteriorated lignin. By combining vacuum and pressure process, the effective impregnation of water solution was achieved. The permeation process due to capillary action with kerosene solution was practical use and useful for the economical preservation of pampas grass. Acetylation was effective for the preservation, however this process removed the original luster of pampas grass.
Glass splinters as physical termite barriers: Optimized material properties in use with and without insecticidal pretreatment minimizes environmental contaminations
1991 - IRG/WP 1476
The major advantage of physically acting barriers against termites using sand or cinder is to be impenetrable for a number of termite species by showing environmental compatibility in a high degree. The major disadvantage of these barriers is the ability of termites to build galleries over them. Glass or glass-like materials are showing optimum material properties: crushed to a particle size from 0.5 to 1.5 mm very thin layers (10 to 20 mm thickness) reliably prevent termite penetration of Reticulitermes santonensis (de Feytaud) and Heterotermes indicola (Wasman) in laboratory studies as well as the penetration of Coptotermes formosanus (Shiraki) in Japanese field tests. On the other hand, the extremely high affinity of pyrethroids to this type of material makes it highly suitable for a stationary pyrethroid-carrier. Gallery-building by termites is completly suppressed after superficial treatment of glass splinters with pyrethroids. The high affinity of pyrethroids to glass surfaces causes high contact insecticidal properties by minimizing leaching and biodegradation-effects at the same time.
M Pallaske, A Igarashi
Le pin: Matériau à contact alimentaire [Pine wood as a material for food contact]
1995 - IRG/WP 95-50040-01
Monoterpenes emitted to air from woods of pine (Pinus nigra, Pinus laricio, Pinus pinaster and Pinus sylvestris) were determined on the one hand by static analysis and by other hand by sampling on the Tenax adsorbent, followed by analysis using thermal desorption, both being combined with gas chromatography coupled with mass spectrometric detection. The major monoterpenes were alpha-pinene and 3-carene from Pinus sylvestris and alpha-pinine and beta-pinene from Pinus pinaster. Camphene, myrcene and limonene were also detected at lower concentration. Alpha-pinene is the major component of Pinus nigra and Pinus laricio. A toxicological evaluation in bibliography was carried out. It suggests in terms of toxicology that pine is a suitable wood species for food contact. At this stage, the study concludes that this conclusion must be confirmed by a panel of experts on organoleptic/olfactive effects of above sustances.
A Waymel, M Lamour, G Labat
Effects of biocides on the extracellular mucilaginous material (ECMM) produced by two wood rotting basidiomycetes
2003 - IRG/WP 03-10469
Growth and production of extracellular mucilaginous material (ECMM) by the brown-rot fungus Gloeophyllum trabeum (FPRL 108 N) and the white-rot fungus Coriolus versicolor (CTB 863 A) was assessed in liquid culture, supplemented with the biocides CuSO4 and cyproconazole. The production of biomass in G. trabeum was significantly influenced by the concentration of CuSO4 in the medium. When CuSO4 was added at 1.0 mmols l-1, biomass was reduced by approximately 35%. At this concentration, the production of ECMM, both absolute and relative to biomass, was increased. Cyproconazole had a similar effect to that observed for CuSO4, although much lower concentrations of the biocide were required to achieve a similar response. Addition of 0.1 mmols l-1 of cyproconazole to the growth medium caused a decrease of approximately 35% in the amount of biomass produced and a 200% increase in the proportional amount of ECMM produced by the fungus. A similar behaviour was also confirmed for C. versicolor . In this case, higher concentrations of CuSO4 were required in order to achieve the same levels of inhibition observed for G. trabeum. Cyproconazole-supplemented cultures also behaved similarly to G. trabeum. A concentration of cyproconazole of 0.1mmols l-1 caused a reduction of 50% in biomass and a 100% increase in the proportional amount of ECMM produced by this fungus. The presence of biocide also led to qualitative changes in the composition of ECMM. Galactose, xylose and glucose were the main components of the polysaccharide fractions of the ECMM produced by the two species growing on control media. As biocides were introduced, the proportion of galactose in the ECMM increased. This was always associated with a decrease in the proportion of glucose for G. trabeum and with a decrease in the proportion of xylose in the ECMM produced by C. versicolor. The results are discussed with regard to the possible role(s) of ECMM in the decay process and its interaction with preservative treatments.
D Vesentini, D J Dickinson, R J Murphy
A bioassay of remedially treated pole material
1987 - IRG/WP 3453
Stubs prepared from treated and untreated utility poles were installed in a test plot and pressure spade treated at the groundline with one of four preservative greases. At one and three year intervals, core samples were removed from the stubs and the improvement in the preservative efficacy due to the greases was assessed. The bioassay investigation showed that only bis(tributyltin) oxide (TBTO) and pentachlorophenol (PCP) reduced fungal growth, although chemical analysis of cores from the stubs suggested that the copper naphthenate grease treatment should also have enhanced protection. This observation may be related to the vapour pressures of the TBTO and PCP, the importance of which has not been established for the protection of wood products in service.
J N R Ruddick, L Parker
Wood preservation in Nigeria - Its increasing relevance, observed constraints and potential as a forest conservation option
1992 - IRG/WP 92-3732
The paper discusses the demand and supply of wood and wood products in Nigeria and points out that in view of the large population (88 million) and search for wood for housing and furniture, the demand exceeds supply. There is great shortage of industrial and domestic woods resulting in underutilization of installed machineries in forest industries and low profit margin. Under this prevailing condition, wood preservation has a definite positive role to play in reducing pressure on productive high forests and timber plantations for logs by prolonging the service life of woods in storage and in service. However, factors such as high depreciation of the local currency, Naira against the U.S. Dollar and British Pound Sterling, high cost of imported wood preservatives, low income per capita especially in the rural areas where over 70% of the population live, have tended to slow the pace of advancement of wood preservation practice in the country. With rising costs of sawn timbers and other wood products coupled with the urgent need to enhance their performance and prolong their service life, the paper concludes that wood preservation has a bright future in Nigeria. Moreover, development of less-toxic and environmentally safe wood preservatives, application of fire retardant preservatives, remedial treatment of utility poles and timbers as well as dimensional stabilization of woods will help greatly to raise the status of wood preservation in Nigeria.
M A Odeyinde, S C Ifebueme
A questionnaire survey to establish the perceptions of UK specifiers concerning the key material attributes of timer for use in marine and fresh water engineering
2004 - IRG/WP 04-10519
Engineers have a key role in making informed decisions on the type of materials to be used in the schemes they design and construct. Currently, in England and Wales, it is believed that some £500m per year is invested in flood and coastal defence engineering. There is a lack of centralised data in the UK holding information on timber for usage in fluvial and, particularly coastal engineering. A questionnaire survey of engineers was carried out. The survey identified the key material properties of timber required by engineers for different end uses. In addition, the survey identified that there was a lack of reliable technical information to support the use of lesser known hardwood species that did not have an established track record of use in marine and fluvial engineering in the UK
J R Williams, G S Sawyer, S M Cragg, J Simm
New method to find out the volatile organic compounds (VOC) of wooden material
2000 - IRG/WP 00-20189
Volatile organic compounds (VOC) of pine, spruce and larch wood were studied using a new technique developed at VTT Chemical Technology. 50 mg of crushed wood material was placed into glass tubes. The tubes were closed with a glass wool, which is pressed with a tube cap. Wood samples were analysed with a gas chromatograph after thermal desorption using four different temperatures (50°C, 100°C, 150°C and 200°C). The gas chromatograph is equipped with a flame ionisation detector (FID) and a mass selective detector (MSD). Green sapwood and heartwood of pine and spruce was studied. For larch wood, fresh and dried heartwood material was analysed. The quality and quantity of volatile organic compounds were quite different in pine sap and heartwood. The amount of total volatile organic compounds (TVOC) was at least five times higher in pine heartwood than TVOC in pine sapwood. The dominating compounds in pine sapwood were carbonyl compounds and in pine heartwood mainly terpenes. Within spruce material, the wide difference between sap and heartwood was not found. In larch wood, the volatile organic compounds was quite different compared with pine and spruce. In larch heartwood, the amount of terpenes was much lower than in pine heartwood but in pine and spruce, no acetic acid was found. The technique can be used for rapid analyse of the quality of wood. The result can be used for reference of decay tests and other properties of wood species.
H Viitanen, K Villberg, K Saarela
Bamboo: A Material Rediscovered
2006 - IRG/WP 06-10577
Bamboo has resurfaced as a valuable raw material as an inexpensive substitute for wood and a variety of value added products for engineered composites. Being a fast growing material available in the tropics, its real value was not realized until recently. Property evaluation studies and efforts to develop processing methods were initiated in the bamboo growing countries in the nineteenth century. Being available almost free its use was limited to handicrafts, paper and low cost housing in rural and tribal areas around the world. These areas having very little access to the developed world developed their own tradition methods to use bamboo for different application. Shortage of wood helped in rediscovery of bamboo. With its recognition as a wonderful material having fastest growth rates, many bamboo-growing nations have chalked out ambitious plans to promote its utilization and raise plantations to relieve pressure on forests. Government of India has initiated an elaborate program to promote bamboo. National Mission on Bamboo Applications an initiative of the Department of Science &Technology, Government of India plans to establish 10 common facility cum training centers in bamboo rich states to realize real value from this versatile material, neglected so far. This paper is intended to bring out the developments featuring processing of bamboo and its utilization in the first half of the 20th century. An update covering the later half of the 20th century will be covered later.