Your search resulted in 10 documents.
Correlation between a laboratory bioassay and field trial conducted to determine the termiticidal effectiveness of bifenthrin
2002 - IRG/WP 02-20248
Details are given of a laboratory bioassay and field trial undertaken to determine the termiticidal effectiveness of the synthetic pyrethroid bifenthrin, when impregnated into Pinus radiata D. Don sapwood specimens. Results show a strong correlation between the laboratory and field methods of evaluation. Protection threshold limits obtained were the same for the two test species of termite employed, Mastotermes darwiniensis Froggatt and Coptotermes acinaciformis (Froggatt). Lower and upper threshold limits obtained for M. darwiniensis in both the laboratory and field were 10 and 20 g/m3. The threshold limits for C. acinaciformis were not determined, but must be less than the lowest retentions tested (<2.5 g/m3 in the laboratory and <5 g/m3 in the field).
J W Creffield, K Watson
Natural durability of wood in ground contact - A correlation between field and laboratory tests
1985 - IRG/WP 2182
A field test is being carried out to evaluate the natural durability of 20 hardwoods. The resistance to decay and termite attack was evaluated in accelerated laboratory tests. The results of the field test after 6 years and 8 months indicate that there is not necessarily agreement between results from laboratory and field tests. It is pointed out that apart from the artificiality of the laboratory tests, a possible cause of the discrepancies can be the different performance of the same wood species in different test sites.
M S Cavalcante, G A C Lopez, R G Montagna, M E S Fosco Mucci
Correlation between different international standard assessment procedures with termites. Part 1: Field exposure
1983 - IRG/WP 1198
Ramin treated with copper-chrome-arsenic (CCA), pentachlorophenate and lindane, each at three retentions, and three other untreated timbers were assessed in the field against Coptotermes lacteus and Nasutitermes exitiosus. Replicate specimens were exposed around five mounds of each termite species over a period of five years in south-eastern Australia. The field results provided the basis for judgement of corresponding laboratory trials conducted accordingly to the standard procedures of Europe, U.S.A. and Australia. In the field none of the wood preservative treatments with-stood termite attack for the full period of five years, not even CCA at the highest retention of 2.3 kg/m³. Merbau and Jarrah were the most resistant timbers but there was noticeable variation between trees.
M Lenz, C D Howick, N Tamblyn, J W Creffield, M Westcott
Correlation between changes in colour and chemical composition during photo-degradation of wood surfaces
2005 - IRG/WP 05-40301
Changes in colour of wood (yellowing) during photo degradation or weathering reflect chemical changes in wood. Therefore, the relationship between changes in chemical composition and CIELAB colour parameters is very important to characterize photodegradation of lignocellulosic surfaces. In this study, the changes in chemical composition and yellowing due to photo-degradation was studied by exposing wood surfaces of Pinus roxburghii (chir pine) to a xenon source. Changes in chemical composition were monitored by measuring IR and fluorescence spectra and were correlated with colour changes. A linear correlation between degradation of lignin and total colour change (E) was observed.
K K Pandey
Natural durability, density and extractive contents of 42 wood species of Bangladesh.
2003 - IRG/WP 03-10490
Natural durability, density and major extractive contents of 42 lesser used or unused wood species of Bangladesh have been studied. Correlation analysis between these properties has been performed. It has been shown that natural durability of these species neither explained by water soluble nor by alcohol benzene extractive contents. Density has a weak but significant positive correlation with durability which indicates that density might have some influence on durability of these wood species.
S Akhter, K Akhter, S C Das
Correlation between modulus of elasticity, mass losses and FTIR spectra of copper treated decayed wood
2006 - IRG/WP 06-10580
The composition of copper-based preservatives will change from copper-chromium to copper-ethanolamine, due to environmental demands. The most important drawback of copper-impregnated wood is the presence of tolerant fungal organisms that have developed an ability to degrade such preserved wood. In order to elucidate these processes, specimens (0.5×1.0×15 cm) made of Norway spruce (Picea abies) were vacuum-impregnated with copper-, chromium-, and copper-ethanolamine-based aqueous solutions (cCu=0.5%), and afterwards exposed to copper-sensitive Gloeophyllum trabeum and copper-tolerant Antrodia vaillantii for various times, between one and eight weeks. After incubation, specimens were isolated, and modulus of elasticity (MOE) losses determined using a nondestructive technique. Mass losses, FTIR spectra, and color changes were measured as well. The results showed that there is significant difference between brown rot decay caused by G. trabeum and A. vaillantii. Decay caused by A. vaillantii is more selective than that caused by G. trabeum. Additionally, it was proven that copper effectively protected spruce from G. trabeum, but not completely against A. vaillantii. Decay of copper-impregnated wood by copper-tolerant fungi is similar to decay of control, unimpregnated wood. Whereas decay of copper-impregnated specimens by G. trabeum, was effectively stopped in its initial stage.
M Humar, B Bucar, F Pohleven
Laboratory bioassay and field trial on imidacloprid and cypermethrin as glueline treatments for softwood plywood
2006 - IRG/WP 06-30405
The effectiveness of imidacloprid and cypermethrin as glueline treatments for protecting phenol formaldehyde (PF)-bonded Pinus radiata (radiata pine) plywood from attack by subterranean termites was evaluated both in the laboratory and field. Imidacloprid was evaluated in two plywood constructions (19 ply x 1.6 mm-thick veneers and 5 ply x 3.2 mm-thick veneers) whereas cypermethrin was evaluated in only one (19 ply x 1.6 mm-thick veneers). There was a strong correlation between the results obtained from the laboratory bioassay and the subsequent field trial. Results of both the laboratory bioassay and field trial demonstrated that imidacloprid at the retention of 20 g a.i./m3 failed to adequately protect test specimens of radiata pine plywood (19 ply x 1.6 mm-thick veneers) from attack by both Coptotermes acinaciformis and Mastotermes darwiniensis. However, it was noted that imidacloprid only marginally failed against attack by C. acinaciformis in the field. In contrast, imidacloprid at the retention of 20 g a.i./m3 was successful in protecting test specimens of radiata pine plywood (5 ply x 3.2 mm-thick veneers) from significant attack by C. acinaciformis, but comprehensively failed against M. darwiniensis. Cypermethrin at the retention of 420 g a.i./m3 was successful in protecting test specimens of radiata pine plywood (19 ply x 1.6 mm-thick veneers) from significant attack by C. acinaciformis. The same retention of cypermethrin performed well in protecting radiata pine plywood test specimens from attack by M. darwiniensis, even though it marginally failed in the laboratory. It is hypothesised that the longer hot pressing time used for the manufacture of plywood test panels of 19 ply x 1.6 mm-thick veneers may have caused more degradation of the imidacloprid active than in panels of 5 ply x 3.2 mm-thick veneers.
J W Creffield, D K Scown
A theoretical-industrial correlation and perspective on copper-based wood preservatives - a review of thermodynamic and kinetic aspects on copper-wood fixation mechanism
2009 - IRG/WP 09-30499
Copper was and it will continue to remain one of the key active component in wood protection industry. Over the past decades, a significant effort from R&D teams in industry, academia and research institutes was directed toward understanding the copper-wood fixation mechanism, optimising the copper retentions in the wood and reduce leaching in order to maximized performance, prolong the lifetime of the treated wood and protect the environment. Significant understanding of copper fixation was achieved in the CCA system, but there are still many uncertainties and grey areas for the newer systems based on copper. Various studies dealing with copper-based systems discussed possible ways to enhance the copper fixation process by either treatment process optimization (e.g. steaming or heating) or by modifying the treatment solution using reactive additives (significant patent activity in this area both from industry and academia). The aim of this study is to review some of the key recent developments and findings on copper fixation mechanism and, starting from a theoretical point of view (thermodynamic and kinetics aspects), identify new possible routes to understand and improve copper-wood fixation in the copper based systems and discuss them also from an industrial/business perspective. The study is also trying to find compelling correlations between various physical and chemical factors and treatment or product parameters which can influence the kinetics of the impregnation process or shift the thermodynamic equilibrium of the copper treatment of wood toward a better copper fixation. The industrial feasibility of these approaches will be reviewed and discussed. As concluding remarks, the study could offer a basis for discussions, new scientific studies, practical and viable approaches to be taken by the wood preservation industry, capable to better understand the copper-wood fixation mechanism, ultimately improving and optimizing the treatment process of wood, and protecting the environment.
R Craciun, M Maier, J Habicht
Correlation of %Acetyl and Fiber Saturation in Acetylated Southern Pine Boards
2012 - IRG/WP 12-40598
Wood acetylation represents a chemical modification that increases the hydrophobicity of wood. The level of acetylation in the wood structure determines the extent of hydrophocity with higher levels providing reduced moisture affinity. Due to the reduced hygroscopic nature of acetylated wood, performance features such as dimensional stability, resistance to termites, and resistance to rot and decay fungi are significantly improved. The fiber saturation point (FSP) represents the theoretical moisture content at which wood cell walls are completely saturated with water and no additional water can be absorbed into the wall structure as bound water. The fiber saturation point of acetylated wood is reduced as compared to unacetylated wood also due to its increased hydrophobicity. In this work, the fiber saturation point of a series of 30.5 cm x 14 cm x 2.54 cm acetylated Southern Pine radius edged deck boards with varied levels of acetyl was determined by measuring the width as a function of moisture content. It was found that the fiber saturation point of acetylated wood correlates with the level of acetyl in the wood substrate. A linear relationship is found between these two factors with increasing levels of acetyl providing a reduction in fiber saturation point. The method used to determine the fiber saturation point in this work provides consistent results with that previously determined via an alternate technique. Unacetylated Southern Pine deck boards were also studied in this work and revealed fiber saturation points consistent with prior determinations in the literature and fitted the relationship between acetyl level and fiber saturation point.
J Dickerson, E Cwirko, J Allen
Three-Dimensional Digital Image Correlation of Strains in Profiled Wood Decking Exposed to Wetting & Drying
2017 - IRG/WP 17-20611
We use three dimensional digital image correlation to measure the strains that develop at the surface of profiled radiata pine (Pinus radiata D. Don) deck boards subjected to a wetting and drying cycle. We hypothesise that surface profiling will change the pattern of strain distribution at the surface of deck boards by concentrating stresses at the base of profile grooves. Five groups of three deck board samples were produced from five different pieces of machine stress-graded radiata pine wood. Two wavy profiles, ribble or ripple, were tested. Flat unprofiled boards acted a control. Each board was fixed to a rigid frame and subjected to a wetting and drying cycle. Full field surface strain data was collected using 3D digital image correlation. Strains varied across the surface of both flat and profiled boards. Profiling changed surface strain patterns; strain maxima and minima developed in the profile ridges and grooves during wetting, respectively, but this pattern of strains reversed during drying. Such a pronounced reversal of strains was not observed when flat boards were exposed to wetting and drying, although there was a shift towards negative strains when flat boards were dried. We conclude that profiling changes surface strain distribution in deck boards exposed to wetting and drying, and causes high strains to develop in the grooves of profiled boards. These findings help explain why checks in profiled deck boards are mainly confined to profile grooves where they are difficult to see, and the success of profiling at reducing the negative effects of checking on the appearance of wood decking.
J Mallet, S Kalyanasundaram, P D Evansa