Your search resulted in 37 documents. Displaying 25 entries per page.
A review of the configuration of bordered pits to stimulate the fluid flow
2005 - IRG/WP 05-40315
As the bordered pits have generally been thought to have an influence on the refractory nature of softwoods, structural behaviour of this conducting pathways is discussed according to the published literature. Various theories on the role of bordered pits to axial flow are expounded in respect to preservative treatment. Pit aspiration is also reviewed....
I Usta
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
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...
I Usta
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
Penetration and distribution of styrene in pressure treated hardwoods
1997 - IRG/WP 97-40094
A styrene impregnation method was used to compare liquid distribution in several species as affected by flow direction, sapwood/heartwood, and method of impregnation. Twenty-five mm ( 1") cubes were cut from the sapwood and heartwood of red maple (Acer rubrum), white birch (Betula papyrifera), yellow poplar (Liriodendron tulipifera), trembling aspen (Populus tremuloides), red oak (Quercus rubra), ...
P A Cooper, T S Janezic, U Srinivasan, A Omidvar
Methods for improving preservative penetration into wood: a review
2002 - IRG/WP 02-40227
Pressure treatment technologies have been available since the mid-1830's, but the processes used for wood treatment are still largely unable to overcome the fundamental limitations of flow through semi-permeable pit membranes. Instead, methods have arisen that attempt to improve treatability of the wood including incising, compression rolling, through boring, or radial drilling. Other a...
J J Morrell, P I Morris
Evaluation of fluid distribution in pressure treated wood in different flow directions
2004 - IRG/WP 04-40281
Among different methods, polymerization technique was chosen to study distribution of fluid through cell types in treated wood. Red maple wood specimens with the size of 2 by 2 by 4 cm (radial, tangential and longitudinal, respectively) were prepared. Styrene monomer was used as the fluid for impregnation; because its physical properties such as surface tension, specific gravity and viscosity fall...
A Omidvar, M H Schneider
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...
S Iddi
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...
I Usta
New technique to analyze impregnation processes
1988 - IRG/WP 2304
Equipment has been developed to measure liquid flow in wood during impregnation processes. Basic principles of flow measurements using directly heated negative temperature coefficient thermistors, and some characteristics of the hardware developed are presented in this paper....
J P Hösli
Flow charts for termite and decay tests to determine the natural durability of Japanese cedar (Cryptomeria japonica D. Don)
2008 - IRG/WP 08-20385
This paper deals with the experimental flow charts that were used for determination the effects of fungal decay and termite attack on Sugi heartwood during the course of the study of “Comparative studies of natural durability of Japanese cedar (Cryptomeria japonica D. Don) among the geographic cultivate”, which was carried out by Usta et al (2006)....
I Usta, S Doi
Creosote movement from treated wood immersed in fresh water: Initial PAH migration
2003 - IRG/WP 03-50201
Creosote has a long history of successful use as a wood preservative, but polycyclic aromatic hydrocarbons (PAHs) in this preservative have raised environmental concerns, particularly when creosote-treated wood is used in aquatic environments. A number of models have been developed to predict the risk of creosote use in aquatic environments, but one limitation of these models is a lack of data o...
Sung-Mo Kang, J J Morrell, J Simonsen, S T Lebow
Alternative technologies for wood wastes recycling - Part B: Biotreatment of PCP- and creosote-treated wood
1998 - IRG/WP 98-50101-18 b
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...
S Legay, P Marchal, G Labat
Bending properties of TCMTB-treated Southern pine sapwood using supercritical carbon dioxide impregnation process
1997 - IRG/WP 97-40080
The effects of elevated pressure and treatment with thiocyanomethylthiobenzothiazole (TCMTB) on the bending properties of Southern pine sapwood were evaluated at pressures ranging from 1,800 to 3,600 psi. All bending properties were affected to some extent by supercritical fluid treatment. Modulus of elasticity and work to maximum load were not significantly affected by pressure levels. Modulus of...
Gyu-Hyeok Kim, S Kumar, E S Demessie, K L Levien, J J Morrell
The treatment of sawn whitewood with organic solvent wood preservative
1982 - IRG/WP 3192
The impregnation schedules approved in the UK for the treatment of sawn European whitewood (Picea abies) with organic solvent borne preservatives result in comparitively high loadings relative to the limited depth of penetration they achieve. Results are presented, which show how substantial reduction in the overall loading may be achieved without concomitant reduction in penetration. A model for ...
L D A Saunders
Probing red maple pit membrane pore size at FSP and OD using polystyrene macromolecules
2001 - IRG/WP 01-40217
A modified solute exclusion technique was used to pressure impregnate a polystyrene molecular weight (MW) series dissolved in styrene into red maple samples at approximately the fiber saturation point (FSP) and oven dry (OD). Radial penetration was less than tangential and FSP less than OD. There was a marked penetration change with MW in the tangential direction, although there appeared to be a ...
A Omidvar, M H Schneider, A R P Van Heiningen
Effects of seed origin and site on both wood density and longitudinal fluid uptake of Sitka spruce (Picea sitchensis (Bong.) Carr.) with height in the tree grown in the United Kingdom
2002 - IRG/WP 02-40226
The variation in density and longitudinal fluid uptake was investigated in short specimens of wood taken from eight seed origins of Sitka spruce trees grown at two sites in the UK. Five trees of each seed origin at each site were sampled at three heights (1, 2 and 3 m above ground
level). The density of the samples decreased with increasing height within the stem. This corresponded with increasin...
I Usta, M D C Hale
Efficiency of wood impregnation processes
1980 - IRG/WP 3151
Many wood impregnation processes have been in use for a very long time, up to 150 years, but they have not been progressively modified. This paper considers impregnation processes in relation to current requirements, particularly impregnation efficiency and energy consumption. The term 'pore' is used throughout in its physical sense and is not confined to botanical 'pore...
B A Richardson
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
A novel solvent penetration assessment technique for wood preservativation treatments using waterborne systems
1990 - IRG/WP 2346
Solvent and hence solute (a.i.) penetration during any wood preservation treatment cycle and the flow pathways taken by the solvent in the wood are crucial elements in determining the adequacy of any treatment. Inadequate solvent penetration into specimens or an inappropriate tissue throughflow pattern during impregnation will markedly affect the distribution pattern achieved by many non-diffusibl...
A J Pendlebury, J Coetzee, E Sorfa, A Botha
Cellular and fractural failure after supercritical fluid impregnation of four wood species
2004 - IRG/WP 04-10503
Supercritical fluids (SCFs) have been investigated for delivering biocides into sawn wood. Pressure differentials during treatment may exceed the compressive or tensile strength perpendicular to grain, creating a potential for transverse deformations that exceed elastic strain limits. Wood treated by SCF processing with CO2, a potential biocide carrier, was inspected macroscopically and microscopi...
M E Anderson, R J Leichti, J J Morrell
Supercritical fluid impregnation of Douglas-fir heartwood with cyproconazole using temperature induced deposition
2003 - IRG/WP 03-40259
A limited understanding of the fundamental aspects of supercritical fluid (SCF) impregnation in wood remains an obstacle to the development of this technology. Developing a better understanding of the effects of various process parameters on treatment results would facilitate more rational development of SCF impregnation. In this project, the effect of treating period and specimen length on su...
Sung-Mo Kang, J J Morrell
Supercritical fluid treatment: Effects on bending strength of white spruce heartwood
1993 - IRG/WP 93-20008
The effects of supercritical carbon dioxide on wood strength were evaluated using white spruce heartwood, a species known to be especially susceptible to collapse during exposure to higher pressures. The effects of pressures of 2000 or 3600 psig and temperatures of 40 or 80°C were evaluated using 30 or 60 minute exposure periods. No significant differences were noted in modulus of rupture or modu...
S M Smith, J J Morrell, E Sahle-Demessie, K L Levien
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
Potential for using dip/supercritical fluid treatments for wood impregnation
2004 - IRG/WP 04-40276
While supercritical fluid impregnation offers tremendous potential for impregnating wood species that resist conventional liquid preservative treatments, the resulting treatments are often not uniform among samples in a charge or between charges. One factor that influences treatment is the dynamic change in pressure that occurs during introduction of the biocide laden supercritical fluid into the ...
Sung-Mo Kang, J J Morrell