Your search resulted in 84 documents. Displaying 25 entries per page.
Rubberwood anatomy and its influence on gaseous permeabilit
1993 - IRG/WP 93-40005
The anatomical structure in several rubberwood (Hevea brasiliensis Muell. - Arg.) samples was examined by use of a Cambridge Stereoscan 600 scanning electron microscope. A series of electron micrographs is presented which illustrate those features anticipated as having an influence on permeability. A series of gas permeability experiments were performed on oven dried samples of rubberwood to deter...
A J Pendlebury, J A Petty
Aspects of diffusion of boron through wood
1984 - IRG/WP 3298
Boron compounds have been shown to be toxic to a wide range of wood destroying insects and fungi. They are cheap, have low mammalian toxicity and their application in the treatment of wood does not demand specialized equipment. These attributes make them specially attractive to developing countries. Currently, however, little is known about the mechanism of diffusion of boron through wood. Effecti...
Comparison of cubic and plug samples for preparation and data assembly in permeability study
2000 - IRG/WP 00-20197
In order to determine if plug experimental samples (PES: 30 x 15 mm2 diameter) could be used for inspection of wood permeability characteristics, radial and longitudinal flow directions were prepared according to either PES or cubic experimental samples (CES: 100 x 20 x 20 mm3) from the sapwood zone of Sitka spruce and treated by tanalith-C according to full-cell process. Results from the two prep...
The use of pressure cycling to improve heartwood penetration in Pinus radiata (D. Don)
1995 - IRG/WP 95-40050
This study investigates the effect of cycling pressure on the treatability of radiata pine heartwood. The results indicate that liquid penetration into the heartwood is affected by the preconditioning method used and pressure treatment time. There is no significant improvement in the penetration of Pinus radiata (D. Don) heartwood when a cycling or pulsation process is used....
P R S Cobham, P Vinden
Co-operative research project on L-joint testing. Sampling after 8 months exposure
1983 - IRG/WP 2208
It was anticipated in Document No IRG/WP/2192 that exposure of L-joints by the European co-operators would take place on 1 April 1983. Where L-joints were exposed at this time, sampling after 8 months exposure is due on 1 December 1983. The present document draws attention to relevant previous documents which describe the sampling methods to be adopted. It also provides Tables for recording the re...
J K Carey, A F Bravery
Some characteristics of Pinus radiata wood from trees subjected to resin extraction
1987 - IRG/WP 3403
35 year old Pinus radiata trees growing in La Puntilla (lat. 37° south, long. 72,4° west), Chile, were subjected to resin extraction 5 years ago. After harvesting them simultaneously with control trees of the same place and age, probes were taken from the bottom of each pole, at 3.4 m, 7.8 m and 11.4 m height. Analysis of ethanol/benzene extract, CCA salt penetration tests and sapstain and brown-rot development rate were performed. The extract content differed in both groups. In the ascendent sense it decreases in unextracted trees and increases in extracted. CCA salt penetration was deeper in treated trees than in untreated. Wood subjectect to resin extraction was less susceptible to sapstain development. No significant difference was detected in both groups in relation to the development of brown-rot.
M C Rose, J Navarrete, G Sandoval, A Bedoya, L Ortega, R Zurita
Options for accelerated boron treatment: A practical review of alternatives
1985 - IRG/WP 3329
Boron wood preservatives are almost exclusively applied by momentary immersion and block diffusion storage. Alternative techniques are described which can be used to accelerate boron treatment. Diffusion coefficients have been derived to define the acceleration of diffusion with increasing temperature. Schedules are described for pressure impregnation of green timber, involving steam conditioning,...
P Vinden, T Fenton, K Nasheri
Direct measurement of fluid flow within wood
1986 - IRG/WP 2248
The problematics of fluid flow mechanism within wood using a permeability concept are highlighted, and the non-feasibility of a practical and versatile model is explained. An alternative method using a negative temperature coefficient thermistor to measure flow velocity directly is presented. The method has been verified in living trees and shows extreme sensitivity for flow above 1 meter/hour. Fo...
J P Hösli
Light organic solvent preservative treatment of glue-laminated radiata pine
1986 - IRG/WP 3380
The high permeability of radiata pine (Pinus radiata D. Don) is associated with ray-tissue and in particular the cross-field pits linking ray-tissue to tracheids. This pathway is absent in the tangential grain direction, leading to poor preservative penetration when treatment is restricted to the radial face - for example, timber fabricated into glue-laminated beams....
Factors affecting leaching of preservatives in practice
1978 - IRG/WP 3113
At the 7th Meeting of the IRG in Poland in May 1975, the findings of collaborative laboratory leaching techniques were discussed, and the dangers inherent in using such results to predict the behaviour of preservative-treated components in service were emphasised. In order to improve our understanding of the factors governing leaching of preservatives in practice, and to identify areas where furth...
R Cockcroft, R A Laidlaw
Co-operative research project on L-joint testing. Progress report to March 1988
1988 - IRG/WP 2315
Further sets of data received from CTFT (France), BAM (Germany) and PRL (UK) after 46-48 months exposure and STU (Sweden) after 22 months exposure are presented and discussed in conjunction with data reported previously. Colonisation and attack of the L-joints has progressed with increasing exposure period. The new data are generally in agreement with those presented previously and the major diffe...
J K Carey, A F Bravery
Fumigation as a remedial treatment: A review of North American literature
1983 - IRG/WP 3253
The development of the use of fumigants for eliminating decay in timber and roundwood in North America is reviewed. Initial experiments on oak wilt identified volatile chemicals which eradicated decay in roundwood. Subsequently, extensive experimentation on Douglas-fir poles in service showed that treatment with chloropicrin eliminated internal decay for more than ten years. Vorlex was also quite ...
J N R Ruddick
Analysing the characteristic role of moisture content for drying and fluid flow in Sitka spruce. - Part 1: The drying process of sapwood and heartwood of two different thickness of Sitka spruce using a kiln. - Part 2: Effects of moisture content on longitudinal permeability of Sitka spruce in vertical variation of the tree
2000 - IRG/WP 00-40173
The characteristic role of the moisture content in Sitka spruce (Picea sitchensis (Bong.) Carr.) that grown in the United Kingdom was examined by this study on the basis of (1) the reduction of moisture content in two different thickness of sapwood and heartwood by kiln drying process, and (2) the effects of moisture content to the longitudinal void volume filled of tanalith-C by the full-cell pro...
Laboratory fumigations to determine the minimum temperature for methyl bromide eradication of the oak wilt fungus in red oak
1983 - IRG/WP 3243
Laboratory chamber fumigations of naturally-infected ret oak log sections exterminatet the oak wilt fungus in sapwood at temperatures down to 0°C. Only low, sporadic fungus survival was observed when log sections were gassed with methyl bromide at -5°C and aired for 4 da. at 0°C. Lower temperature treatments were not effective even if gas levels or exposure times were increased by 50%....
E L Schmidt
Studies on the biological improvement of permeability in New Zealand grown Douglas fir
1983 - IRG/WP 3231
This report outlines progress towards optimizing conditions for water storage of New Zealand grown Douglas fir with the aim of improving permeability to water-borne preservatives, in particular CCA. Small scale laboratory tests are in progress but the need to scale up to potential commercial applications is being considered. Mixed populations of bacteria isolated from 10 week water sprinkled Dougl...
K J Archer
The effects of density on vertical variation of permeability of Sitka spruce within tree
2000 - IRG/WP 00-40156
Tree improvement of Sitka spruce is a combination of silviculture and tree breeding aimed at producing higher quality products including increased growth rate and timber yield, and wood density. It is useful to know annual ring structure and density distribution when studying the quality of wood, grading it, or determining how the wood structure affects residual flow in softwoods. Since density is...
Practical testing of wood preservatives to prevent weathering damage and infection by micro-organisms on spruce and pine
1989 - IRG/WP 3530
Brush application, is generally used to prevent wooden window frames from decay caused by influence of weathering and fungi. Accordingly 10 boards of pine (Pinus sylvestris) and spruce (Picea abies) were treated with 10 commercially used wood preservatives. The efficiency of fungicides by using chiptest and blue stain test (EN 152), the effectiveness against weathering as well as the course of col...
R Gründlinger, O Janotta, H Melzer, K Messner
Some relationship between physical characteristics and treatability of Bolivian woods
1987 - IRG/WP 3434
Using the available data on physical characteristics of 25 Bolivian woods, some relationships between porosity, specific gravity and treatability (hot and cold open tank process with 5% pentachlorophenol) were analysed. The aim of this report is to give information on technical characteristics of Bolivian hardwoods which have been studied in this country by Centro de Desarrollo Forestal and in Per...
A S Viscarra
Influence of a dipping preservative treatment on the performance of wood finished with waterborne coatings
1998 - IRG/WP 98-40121
Within a larger European research project on the performance of joinery finished with waterborne coatings, the influence of a water based dipping preservative treatment was studied in several ways. Six different waterborne coatings were tested with and without a preservative underneath the coating. The performance was tested on pine sapwood and spruce panels in a 2-year outdoor weathering trial on...
M De Meijer, J Creemers, W Cobben, P Ahola
Effect of permeability and extractives on the decay rate of southern pine sapwood in above grund exposure
2005 - IRG/WP 05-20310
The effects of wood permeability and hydrophilic and hydrophobic extractives on the decay rate of southern pine sapwood in above ground exposure were investigated. Permeability was determined by water sorption measurements, and the effect of extractives was studied by pre-extracting the test samples prior to outdoor exposure using water to extract hydrophilic extractives or sequential methanol/cy...
D D Nicholas, T Schultz, L Sites, D Buckner
Methyl bromide eradication of the oak wilt fungus in logs. Laboratory and field fumigation
1981 - IRG/WP 3168
Concern over accidental introduction of the oak wilt fungus (Ceratocystis fagacearum) into oak-importing nations has prompted a study supported by the U.S. National Lumber Exporter's Assn. to assess the efficacy of methyl bromide fumigation to eradicate the fungus from logs and lumber. Laboratory and field fumigation trials to develop a reliable and realistic treatment were performed on r...
E L Schmidt, M M Ruetze, D W French
The influence of gaseous oxygen concentration on fungal growth rates, biomass production and wood decay
1998 - IRG/WP 98-10283
The effects of air and several levels of oxygen balanced with nitrogen (% oxygen (v/v) nitrogen to 100%) on growth rates, biomass production and wood decay were investigated. The best technique for measuring daily growth rates in anaerobic jars was found to be by using 40 mm petri dishes which were attached to the walls of the jars. At the end of the test period the same petri dishes were also use...
S M Kazemi, D J Dickinson, R J Murphy
Microwave conditioning of Pinus radiata D. Don for preservative treatment
2000 - IRG/WP 00-40182
This paper reviews the effect of pressure steam conditioning on the permeability and treatability of green radiata pine heartwood and the potential for substituting microwave conditioning for steaming. The penetration of liquids into radiata pine occurs mainly in the radial tissue. The permeability of green radiata pine improves following steam conditioning by blowing out the soft radial tissue. T...
P Vinden, G Torgovnikov, J Romero
Co-operative research project on L-joint testing. Progress report to March 1984
1984 - IRG/WP 2211
Each participant was intended to expose L-joints in the main trial on 1 April 1983 and the first sampling, after 8 months exposure, was to be undertaken on 1 December 1983. Some participants have had to vary this schedule. Results are presented from CTFT (France) and PRL (United Kingdom). These show a greater effectiveness by the double vacuum treatments compared with the 1 minute dip treatments. ...
J K Carey, A F Bravery
Changed permeability and surface properties of hornbeam wood due to its degradation by erosive strain of Phanerochaete chrysosporium
2004 - IRG/WP 04-40290
Specimens of hornbeam wood were submitted to a medium-term degradations by erosive fungus Phanerochaete chrysosporium. Biodegradations of specimens resulted in their apparent structural alterations, changes in permeability and increased intensity of interactions with polar liquids. Modified physical properties of biodegraded wood may significantly influence its penetration with polar media and che...
R Solár, S Kurjatko, L Reinprecht, M Mamon, V Vacek