IRG Documents Database and Compendium


Search and Download IRG Documents:



Between and , sort by


Displaying your search results

Your search resulted in 29 documents. Displaying 25 entries per page.


The influence of carrier fluid type on the efficacy of a wood preservative against cavity forming soft rot
2000 - IRG/WP 00-30244
Propiconazole was applied to Scots pine sapwood (Pinus sylvestris) and beech (Fagus sylvatica) using three different carrier systems selected on their varying ability to swell timber. The effects of microdistribution on the activity of cavity forming soft rot fungi were examined to determine the practical benefits of using swelling and non-swelling carriers with this active ingredient. Efficacy of the active ingredient delivered by different carriers against micro-fungi was assessed using EN (V) 807 (1998). After exposure, the relative mean mass loss of the timber samples was used to measure the extent of decay.
P A Hodges


Hydrofluoroalkanes as carrier solvents for timber preservation
2009 - IRG/WP 09-40463
Hydrofluoroalkanes are a specific category of hydrofluorocarbon (HFC) commonly used in refrigeration applications. Some HFCs hold potential for use as carrier fluids for preservatives used to protect timber above ground. They do not share the most significant disadvantages of currently used carriers for these applications. At ‘conventional’ operating pressures, they are capable of rapid, full penetration of some timbers generally considered refractory, such as spruce and the heartwood of radiata pine. But they are comparatively expensive and, while they are not detrimental to the ozone layer, they would contribute significantly to the greenhouse effect if released. Impregnation process conditions can be optimised to maximise biocide solubility and impregnation speed and depth.
M J Kennedy, B Walker, C Erskine


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. For measuring lower velocities, the method needs improvement.
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 process from base (1 m) to apex (3 m) of the tree in sapwood zone. Accordingly, conclusions on indication of the drying process of sapwood and heartwood, and vertical variation of longitudinal flow with effects of moisture were listed separately: (1) Comparison of Drying Characteristic of Sapwood and Heartwood: The two different thickness (300x30x30 mm3 and 300x20x20 mm3) of sapwood and heartwood of Sitka spruce was dried using the suggested drying schedule in kiln. The reduction of moisture was schematically diagrammed according to sapwood and heartwood stakes. The reduction of moisture followed the same downward trend that sapwood (S) loses more moisture than heartwood (H) although the small stakes of S and H lost moisture rapidly compared with the large ones. (2) Vertical Variation of Moisture Content and Longitudinal Permeability: The 90 kiln dried defect free sapwood stakes (150x25x25 mm3) of Sitka spruce was taken from base to apex of the trees at 1, 2 and 3 m above ground level. After having the determination of moisture content in each experimental stake, the treatment was carried out by the full-cell process with CCA preservative (Tanalith-C) using a model pressure treatment plant. Significant differences observed among the tree heights from 1 to 3 m showing that slightly increases of moisture content from base to apex and conversely decreases of longitudinal void volume filled by preservative fluid.
I Usta


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 alternative ways. The developed strategy is described in this paper and illustrated by a few examples. Part B - The second one is based on an oxidative degradation of organic compounds directly in the wood: oxidative degradation by fungi. Few examples are presented in this paper. Three fungi are tested directly on treated wood. High levels of contaminants are tested around 0.6 g of PCP/kg and 3.7 g of 8 PAH/kg of wood. Few oxidation products generated by this biological treatment are identified. An ecotoxicological assessment is performed to validate this process. Technical feasibility of these developed processes as well as economic aspects are discussed,
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 rupture differed among individual pressure levels, but the effects on bending strength were less definitive. TCMTB retention had little or no effect on properties, suggesting a lack of chemical interactions between the lignocellulosic matrix and this biocide. The effect of treatment on bending properties was unexpected as previous trials on smaller specimens and selected composite panels had shown no negative effects. Further trials of other wood samples with increased replication are planned to more fully understand potential treatment effects on strength properties.
Gyu-Hyeok Kim, S Kumar, E S Demessie, K L Levien, J J Morrell


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 increasing ring width. The change of the longitudinal fluid uptake from base to apex showed an inverse trend to density. Site had an effect on density and increased density reduced fluid uptake. Seed origin had a marked effect on density and fluid uptake but the two factors showed no correlation. Some seed origins showed a variety of desirable characteristics and recommendations are made for the selection of seed origins for further UK plantations based on growth rate, density, tree form and permeability.
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 using locally grown Sitka spruce, Queen Charlotte Islands (QCI) provenance, from Beddgelert Forest in North Wales. The full cell experimental schedules used were: initial vacuum 15 minutes at -0.84 bar and various pressure periods that was 5 bar pressure in radial flow direction for 15, 45, and 60 minutes, 3 bar pressure in longitudinal flow direction for 3, 6, and 9 minutes. No final vacuum was applied. After the treatment, the fluid uptake was calculated, and the fluid retention was determined on a whole-block basis. After fixation, plugs were dried and cut longitudinally through the centre and copper penetration was determined by spraying a 1% solution of Chrome Azurol-S on the cut surface and observing the blue colour indicative of copper. The preservative penetration was then measured by image analyser as depth (mm) and as total treated area (%). From the experimental data, it was concluded that the suitable schedules are 5 bar pressure for 45 minutes for the radial flow direction, and 3 bar pressure for 7 minutes for the longitudinal flow direction. Therefore these schedules are suggested to be used to examine the permeability of the different seed origins in both radial and longitudinal flow directions.
I Usta


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 microscopically. Both cell wall damage and smooth fracture surfaces appeared in the cellular structure. Damage was related to the rates of pressurization and venting and appeared to be species-specific. Cell walls were damaged during pressurization, whereas fracture damage occurred during venting. Specimen dimensions, permeability and anatomical structure are critical variables in developing SCF processes for biocide treatment of wood and wood-based products.
M E Anderson, R J Leichti, J J Morrell


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), basswood (Tilia americana), red pine (Pinus resinosa) and American beech (Fagus grandifolia). Samples at 20-25% MC were sealed to permit either radial only or tangential only penetration or left unsealed and vacuum or pressure treated with catalysed and pigmented styrene. The styrene was polymerized in situ and the gross retention and penetration evaluated and the distribution in various cell types evaluated by light microscope. There were higher retentions and penetrations for tangential flow than for radial flow for all examined hardwoods except for red oak; red pine also was penetrated more readily in the radial direction. For transverse flow, the fibres were the most important flow paths in most hardwoods, with relatively little ray penetration, except in oak and the red pine (softwood). In uncoated samples, the vessels were the main flow paths, as expected, but the fibres were also significantly penetrated.
P A Cooper, T S Janezic, U Srinivasan, A Omidvar


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 supercritical fluid impregnation of cyproconzaole was evaluated on Douglas-fir heartwood using temperature decrease to induce biocide deposition. The results showed that biocide movement was slower than expected, and suggested that diffusion was the primary phenomena accounting for biocide penetration into the interior of sample. Further trials will be required to better understand the mechanism of biocide movement.
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 modulus of elasticity between specimens treated with supercritical fluid at selected pressures, temperatures or exposure periods or between treated and untreated control samples. Furthermore, no evidence of crushing or deformation were noted in specimens exposed to higher pressures. These results indicate that exposure to supercritical conditions should not adversely affect material properties of spruce.
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 alternative ways. The developed strategy is described in this paper and illustrated by a few examples. Part A - The first one is based on the use of supercritical fluid as C02 to solubilize organic compounds as organochlorine compounds and Polycyclic Aromatic Hydrocarbons (creosote) from treated wood. Kinetics results of this extractive process are presented on the basis of 200 g of wood.
L Schrive, C Perre, G Labat


Controlled envelope treatments of Pinus sapwood, achieved by modifications to impregnation process and carrier solvents
2003 - IRG/WP 03-40258
Specimens of slash pine or radiata pine were treated to a target retention of 0.02% m/m permethrin with conventional light organic solvent fluids or with oil-modified fluids (Tanalith® T). Best achievable envelopes from LOSP fluids were poorly controlled, penetrating not only the target outer 0-5 mm zone (mean 0.019%, RSD 28%), but also breaking through into the 5-10 mm zone (mean 0.013%, RSD 37%) and further into the >10 mm zone (mean 0.011%, RSD 52%). With the oil-modified fluids, the target 0-5 mm zone received a mean retention of 0.024% (RSD 30%), with 0.003% (RSD 44%) in the 5-10 mm zone and <0.002% the >10 mm zone. This tight control of toxicant distribution facilitates economical termite control.
M J Kennedy, P R S Cobham


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 treatment vessel. Subcritical conditions during these time periods sharply reduce biocide solubility, setting the stage for more variable treatment results. One approach to limiting these variations would be to deliver a large percentage of the biocide into the wood prior to SCF treatment. This would place the biocide closer to their intended locations with in the wood as it was solubilized. The potential for using a dip treatment to deliver biocide into the wood surface followed by SCF impregnation was assessed using Douglas-fir heartwood blocks and cyproconazole. Dipping in biocide tended to produce slightly more uniform internal retentions, however, inclusion of otherwise untreated samples in the vessels indicated that biocide also diffused from the blocks into the SC-CO2 where it was available for uptake into other wood. The results suggest that surface loading of wood prior to SCF treatment produced only marginal gains in uptake and is probably not practical.
Sung-Mo Kang, J J Morrell


Preservative treatment of wood-based composites with a mixture formulation of IPBC-silafluofen using supercritical carbon dioxide as a carrier gas
2003 - IRG/WP 03-40251
Wood-based composites treated with a mixture formulation of a fungicide, 3-iodo-2-propynyl butylcarbamate (IPBC) and a termiticide, silafluofen using supercritical carbon dioxide (SC-CO2) as a carrier solvent were tested for their resistance to decay and termite attack in the laboratory. The treatment solution was prepared by mixing both biocides (IPBC 10 + silafluofen 1) with a co-solvent, ethanol to have an identical ratio of each constituent in the commercial formulation for superficial treatment of wood. SC-CO2 treatments were conducted at 35oC/7.85 MPa, 35oC/9.81 MPa and 55oC/11.77 MPa with a direct introduction of the biocidal solution into the treatment vessel where specimens (210 x 30 mm x thickness) of medium density fiberboard, hardwood plywood, softwood plywood, particleboard and oriented strand board were placed. Laboratory tests were conducted with the treated materials according to Japanese standard methods. Results of laboratory tests indicated that the current treatment conditions significantly enhanced the resistance of the treated wood-based composites against fungal and termite attacks. Comparison with the results obtained for wood-based composites treated with an individual biocide showed that treatment with a mixture would not cause any negative effect to the efficacy of each biocide, although the amount of each constituent in a mixture formulation must be carefully decided to provide wood-based composites with a satisfactory performance against any biological degradation when SC-CO2 is used as a carrier solvent.
K Tsunoda, M Muin


A novel chemical barrier system, KORDON® TMB, for the protection of buildings against subterranean termites using a synthetic matrix as carrier for the chemical
1998 - IRG/WP 98-10264
Kordon TMB is a new chemical barrier system for installation beneath concrete slab-on-ground constructions using a matrix other than soil as carrier for the termiticide. The product consists of a synthetic foraminous web (blanket) carrying the synthetic pyrethroid deltamethrin. The blanket is laminated on the upper side to a standard 0.2mm thick moisture vapour membrane of low density polyethylene (LDPE) and on the other side to a sheet of black 0.05mm UV-stabilised LDPE. Installation of the barrier follows existing building practice of setting down and sealing the vapour barrier, as required, during site preparation for building. Results of the evaluation of component materials and key features of the Kordon TMB system, which has been ongoing for the past eight years, are briefly discussed in this paper. Experiments simulated the use of treated webbing with or without LDPE under concrete slabs at sites near Griffith (New South Wales) in a semi-arid part of eastern Australia and near Darwin (Northern Territory) in the wet/dry tropics of northern Australia. In these trials timber has been protected from subterranean termite attack for more than seven to eight years at rates of 0.25 -2.50 g/m2 deltamethrin. In another series of studies, samples of wood protected by the webbing with LDPE were exposed to termites using a below-ground exposure method. To date, these trials have demonstrated successful protection of timber from termite attack for periods of six months to two years for rates from 0.01 - 1.00g/m2 deltamethrin. Laboratory studies have been conducted to simulate the Kordon TMB seals around service penetrations through the concrete slab. The first trial was conducted at incubation temperatures optimal to termite requirements, while a second series investigated the effectiveness of seals at lower temperatures more closely resembling conditions under a concrete slab. Based primarily on this work, Kordon TMB has been developed in Australia for approval by regulators.
M Lenz, P Morrow, S Runko


Methods for improving preservative penetration into wood: a review
2002 - IRG/WP 02-40227
Pressure treatment technologies have been available since the mid-1830&apos;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 approaches have altered the characteristics of the treatment fluid primarily by reducing viscosity. None of these methods has been completely successful. This paper reviews the methods employed to improve preservative penetration in wood and outlines research needs for addressing treatment of refractory wood species.
J J Morrell, P I Morris


Performance of Oriented Strandboard, Medium Density Fiberboard, Plywood, and Particleboard Treated with Tebuconazole in Supercritical Carbon Dioxide
2005 - IRG/WP 05-30364
The performance of oriented strandboard (OSB), medium density fiberboard (MDF), particleboard and plywood treated with tebuconazole using supercritical carbon dioxide was investigated over a 48 month exposure under harsh above ground conditions in Hilo, Hawaii. Samples treated to low retentions (<0.20 kg/m3) tended to experience decay at rates that were only slightly lower than those found with untreated controls. This was particularly true with aspen OSB, which failed within 30 months regardless of treatment level. Most other samples treated to higher retentions remained free of fungal decay over the test period. Tebuconazole treated Douglas-fir plywood provided the best performance, demonstrating the benefits of combining a moderately durable heartwood with supplemental preservative treatment. The results indicate that SCF-treated wood provides reasonable performance in non-soil exposures under severe decay conditions.
J J Morrell, M N Acda, A R Zahora


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 between those of many preservatives. Before impregnation, apart from the uncoated specimens, some samples were coated with epoxy resin such that lateral flow along with longitudinal flow could be studied. Full cell process with the exception of final vacuum was applied for impregnation. Thin sections from the treated wood were prepared to be microscopically examined for distribution study. The results indicated uniform fluid distribution in lateral flow (both in radial and tangential) and non-uniform distribution in longitudinal flow as well as flow in uncoated specimens. Since uniform distribution of preservative among different cell types is very important, it is recommended that in some cases such as poles, piles, posts and sleepers, end coating of wood should be done before impregnation.
A Omidvar, M H Schneider


Internal pressure development within Oriented Strand Board during supercritical fluid impregnation
2000 - IRG/WP 00-40175
Supercritical fluids (SCF) offer an attractive alternative to conventional treatment processes for delivering material into wood, but there are many unanswered questions concerning the technology. One major concern is the potential for the development of excessive pressure gradients in the wood that might exceed the material properties and lead to crushing or other pressure-induced damage. Previous studies suggest that the pressure gradients in solid wood of some species exceed the material properties of the wood, resulting in collapse or splitting, but there is little data on these processes in composites. The rates of pressure change were studied in oriented strand board (OSB) during SCF treatment with carbon dioxide. In general, pressure equilibrated far more rapidly in OSB than in solid wood. The presence of gaps and voids in the composite apparently permit more rapid equilibration of pressure, thereby avoiding the problems found with less permeable solid woods. Further studies are underway to incorporate the pressure development data into a model to predict solubility of biocides in the composite during treatment.
G Oberdorfer, P E Humphrey, R J Leichti, J J Morrell


Efficacy of Avermectin B1 dust and bait formulations in new simulated and accelerated field tests
1985 - IRG/WP 1257
Avermectin B1 on a silica carrier dust was used in dust and bait formulations whose efficacy against Reticulitermes flavipes was assessed in new simulated and accelerated field tests. A 0.5 mg avermectin/mg dust and a bait with 50 ppm avermectin in paper pulp sandwiched between pieces of corrugated boxboard caused nearly complete mortality in bioassays and suppression of foraging in field tests. These results indicate that the formulations can be developed into control effective gallery injection and/or bait treatments.
G R Esenther


Development of preservative treatment method using sub and super critical carbon dioxide
2007 - IRG/WP 07-40385
Significant efforts have been devoted for developing biocide impregnation method into wood materials using supercritical fluid. Developing better understandings of fluid phase and its effect on treatment results would facilitate a more rational development of supercritical fluid (SCF) impregnation. In this project, the preservative treatabilities under super- and sub-critical fluid conditions were evaluated using Pinus Radiata sapwood. Treating characteristics are discussed in relation to different fluid phases and treatabilities (biocide penetration, distribution, and retention).
Myeung-Won Cho, Sung-Mo Kang, Gyu-Hyeok Kim


Comparison of permeability at different levels of moisture content in Bornmullerian fir (Abies bornmulleriana Mattf.) and Eastern spruce (Picea orientalis L.) impregnated under vacuum/pressure through full-cell method by using CCA and CCB of different concentrations
2007 - IRG/WP 07-40366
In this study, a comparison has been made in terms of the combined, longitudinal, tangential, and radial permeability of the species of Bornmullerian fir (Abies bornmulleriana Mattf.) and Eastern spruce (Picea orientalis L.) with moisture contents of 50 % and 15 %, which were impregnated under vacuum/pressure through full-cell method by using water-borne wood preservatives (impregnation materials) of Tanalith-C (CCA : copper-chromium-arsenic) and Wolmanit-CB (CCB: copper-chromium-boron) in concentrations of 2.5 % and 3.0 %. The experimental data obtained were examined in terms of the wood species concerned, level of moisture, type of the impregnation material used, concentration of the solution and the direction of the liquid flow, by taking as basis the level of absorption of the two different impregnation materials by the cell cavities of the wood species tested. Results of the tests made by using the impregnation materials of CCA and CCB in different concentrations (2.5 % and 3.0 %) have shown that the level of absorption (in the species of Bornmullerian fir and Eastern spruce) was the highest when the wood was dry (with a moisture of 15 %); and that when the wood was wet (with a moisture of 50 %), absorption of the wood preservative liquid was the highest in both of the species particularly when CCB is used. The results of this study have also revealed that the level of absorption of the impregnation material under all the experimental conditions was higher in the wood of Bornmullerian fir, compared to that of the Eastern spruce. The analyses made by using different concentrations of the impregnation materials have shown that in general, the impregnation materials of lower concentrations were absorbed relatively better by the wood, based on the direction of the liquid flow. In order to see the level of absorption of the impregnation materials, the amounts of liquid flow in different anatomic directions were compared in both species, and it was seen that under all the experimental conditions, the decreasing order of absorption according to direction was: combined>longitudinal>tangential>radial.
I Usta


Next Page