Your search resulted in 298 documents. Displaying 25 entries per page.
Bacterial degradation of wood cell wall: A review of degradation patterns
1990 - IRG/WP 1460
Information from bacterial degradation studies of 60's and 70's was reviewed by Nilsson in 1982. The application of electron microscopy to this area in recent years has provided much useful information and has eliminated earlier scepticism among workers about the ability of bacteria to degrade lignified wood cell walls. Studies using transmission electron microscopy together with...
A P Singh, J A Butcher
Chemically modified tannin and tannin-copper complexes as preservatives for wood
2001 - IRG/WP 01-30271
The efficacy of Mimosa tannin, chemically modified tannin, and tannin-copper complexes as wood preservatives was studied. When the tannin-ammonia-CuCl2 solutions were impregnated into wood specimens in a one-step procedure, a large quantity of the tannin-copper complex was fixed in the specimens. Little of the complex was leached from specimens by a weathering treatment, and these specimens showed...
H Yamaguchi
Oral toxicity of TIM-BOR®, Bora-Careä, boric acid and ethylene glycol against the formosan subterrean termite and easter subterrean termite
1993 - IRG/WP 93-10045
Oral toxicities (LD50) of boric acid, TIM-BOR® (disodium octaborate tetrahydrate: DOT) and BORA-CAREä (40% DOT in ethylene glycol) and ethylene glycol (ca. 80% monoethylene and ca. 20% polyethylene glycol) were estimated. Oral toxicities of BORA-CAREä were significantly higher (LD50: 256.2 µg/g DOT and 304.9 mg/g BAE) than TIM-BOR® alone (LD50: 408.2 µg/g DOT and 485.7 µg/g BAE); indicating...
M Tokoro, N-Y Su
The degradation of wood surfaces by dilute acids
1985 - IRG/WP 3326
Thin radial/longitudinal sections(~100 µ) of Corsican Pine (Pinus nigra) and Lime (Tilia vulgaris), were exposed to Sulphuric, Sulphurous, nitric, acetic, and formic acid at 40°C in the pH range 2-6. After about 3 months exposure to Sulphuric, nitric, acetic and formic acid at pH 2.0 Pine lost some 20-25% of its tensile strength. Losses in tensile strength due to sulphurous acid were greater bei...
P D Evans, W B Banks
The fixation of copper in Pinus sylvestris using the sodium salts of two polyhydroxycarboxylic acids
1992 - IRG/WP 92-3706
As part of the research concerned with the development of fixed, copper based preservatives, the salts of polyhydroxycarboxyIic acids, have been used in copper sequestration studies and fixation trials in Pinus sylvestris splinters. Selected compounds have been shown to be effective sequestrants at low concentrations allowing alkaline solutions to be formulated. Leaching trials following a 48 hour...
M Bacon, J A Cornfield
A model for attack at a distance from the hyphae based on studies with the brown rot Coniophora puteana
1995 - IRG/WP 95-10104
In timber infested by brown rot fungi, a rapid loss in strength is attributed to production of hydroxyl radicals (HO·) at a distance from the hyphae. The immediate precursor is Fenton's reagent (Fe(II)/H2O2), but the pathways leading to Fe(II) and H2O2 have remained unclear. Cellobiose dehydrogenase, purified from cultures of Coniophora puteana, will couple oxidation of cellodextrins to ...
S M Hyde, P M Wood
Detrimental effects of boric acid on symbiotic protozoa in Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)
2000 - IRG/WP 00-10366
In laboratory choice bioassays, Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki were offered a tunneling soil consisting of boric acid (BA) mixed with sterilized soil at concentrations of 0.05, 0.25, 0.50, 1.00, 2.00, or 4.00 percent AI (wt:wt). Termites could choose to remain in their main nest that contained non-treated artificial substrate and adequate food, or tunnel throug...
B M Kard
Anti-sapstain chemicals for diffusion treatment of rubber wood
1986 - IRG/WP 3367
Performance of Sinesto B and Akzo EN 494, two formulated products of alkyl ammonium compounds, was tested as fungicidal additive in the boron solution to control mould and stain during diffusion storage of rubber wood. Sinesto B at 2.0% (a.i.) concentration has given good control over mould and its protection against sapstain was only satisfactory. Akzo EN 494 at 0.7% (a.i.) concentration has give...
R Gnanaharan
Removing Cu, Cr and As from CCA treated yellow pine by oleic acid
2003 - IRG/WP 03-50202
In this study, CCA treated yellow pine utility poles were cut into three different dimensions and 4 different pH levels (2, 2.5, 3.5 and 5) of Oleic acid was used. The leached wood samples were collected at the end of the 1, 3, 7 and 14 days to determine the remaining Cu, Cr and As concentrations. The concentrations of Cu, Cr and As were determined by X-RF. The effects of pH, dimension and duratio...
E D Gezer, Ü C Yildiz, S Yildiz, E Dizman, A Temiz
The efficacy of boron preparations
1987 - IRG/WP 3400
The toxicity threshold of boric acid for egg larvae of Hylotrupes bajulus Linné is approx. 0.4 kg/m³ of wood (71 g B/m³) over a 12-week test period, and approx. 0.3 kg/m³ of wood (53 g B/m³) over a 6-month test period. The corresponding values for borax are 0.5-0.6 kg/m³ of wood (56-68 g B/m³) and 0.3-0.4 kg/m³ of wood (34-45 g B/m³). The values are somewhat lower in the case of the egg l...
J T De Jonge
A study of methanogenesis and sulphate-reduction: A possible source of explosive gas mixtures in a gold mine
1989 - IRG/WP 1399
Previous work isolated anaerobic bacteria from timbers and drainage water in a gold mine. The present work identifies the predominant methanogen in the mine ecosystem as Methanobacterium bryantii and sulphate-reducing isolates as Desulphovibrio desulphuricans and Desulphotomaculum antarcticum. Laboratory studies using model systems evaluate the activity of methanogenic and sulphate-reducing bacter...
L D Abraham, J F Putterill, A A W Baecker
Redistribution of boric acid in radiata pine during drying after preservative treatment
1993 - IRG/WP 93-40010
Samples of 100 x 50 mm² radiata pine were processed with a variety of options to produce dry, boron-treated wood. Concentrations of boric acid in the central one-ninth and in the whole of the wood cross-sections were determined by chemical analysis and compared. Diffusion treated material was dried by air, conventional kiln (70/60°C), or high temperature kiln (120/70°C). Four different predryin...
A J Bergervoet, D R Page, J A Drysdale
A comparison of fatty acid and molecular profiles for identification of wood colonizing basidiomycota
2003 - IRG/WP 03-20278
Two methods that are currently being employed to detect and identify wood decay fungi are Fatty Acid Methyl Ester (FAME) analysis and Restriction Fragment Length Polymorphism (RFLP) analysis. A FAME library and RFLP library for 9 species and up to 10 strains within each species have been developed. The profiles generated by these methods have been compared for each species and strain to test for...
T C McElroy, L Prewitt, S V Diehl
Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 4: Conversion reactions during storage
1974 - IRG/WP 332
Precipitates simulating those produced in wood by preservative fixation reactions were prepared by the reduction of Boliden K 33 and Celcure AP solutions with hydrogen peroxide and hydrazine. The pH changes on aging at 20 and 50°C were studied and related to the chemistry of fixation previously described. Hydrolysis of copper arsenates may render arsenic acid temporarily water soluble pending pre...
S-E Dahlgren
Effects of the sulfuric acid modification of CCA treating solution
1987 - IRG/WP 3415
Sulfuric acid modification of CCA treating solution is often used to control the formation of sludges and undesirable deposits on the surface of treated wood. The consequences of sulfuric acid addition are examined in this work and negative effects are shown to far outweigh any benefits. Major risks include the loss of copper due to leaching from treated wood and the accelerated corrosion of treat...
R F Fox, H J Fry, E A Pasek, A S Ross
Preservation of basidiomycete hyphae in ancient waterlogged wood materials
1992 - IRG/WP 92-1536
Studies on waterlogged archaeological wood show that basidiomycete hyphae may persist as long as 800 years. In two pine wood samples with Phellinus pini heartrot, one from the foremast of the ship Vasa and the other from a bulwark constructed in the first part of the 12th century, numerous resin covered hyphae were observed. Hyphae with clamp connections that were associated with brown and white r...
T Nilsson, G F Daniel
A combined method for drying and preserving wood in a single step process
2000 - IRG/WP 00-40183
Based on a convective dryer, this process allows to dry and treat wood blocks with diffusible preservatives in the same time. A boric acid solution (heated to fix the wet temperature of the system) is pumped and introduced in the flow system through a venturi, where the air coming back from the drying cell also arrives. The role of the venturi is to create a dispersion of boric acid solution micro...
O Colin, C Dupuis, E Mougel, A Zoulalian, M-F Thévenon
Antifungal activity in metabolites from Streptomyces rimosus
1991 - IRG/WP 1495
The objective of this study was to evaluate the efficacy of antifungal metabolites from Streptomyces rimosus for controlling the growth of sapwood-inhabiting fungi: sapstain fungi - Ceratocystis coerulescens, Ceratocystis minor, Ceratocystis pilifera, and Aureobasidum pullulans; mold fungi - Aspergillus niger, Penicillium spp, and Trichoderma spp. Production of antifungal metabolites by Streptomyc...
S C Croan, T L Highley
Effects of hard water, sea water and humic acid on the release of CCA components from treated wood
2005 - IRG/WP 05-50228
Leaching medium is an important factor affecting release of preservative components from treated wood because physical and chemical characteristics of medium increase or decrease the solubility of fixed preservative components. This study evaluated the leaching properties of copper, chromium and arsenic elements from chromated copper arsenate (CCA)-treated wood specimens subjected to laboratory le...
S N Kartal, W J Hwang, Y Imamura
Diffusion treatment of gauged radiata pine timber using "Boracol 20"
1987 - IRG/WP 3437
Green gauged 100 x 50 mm radiata pine timber was preservative treated by brush application of "Boracol 20" followed by diffusion storage. Preservative retention analyses indicated that retention requirements in the core could be achieved within a six week diffusion period, thus representing a time saving of 25% over conventional boron treatment of rough-sawn radiata pine. Similar treatment of kiln...
D R Page, P Vinden, S Retter
Environmental impact of PCP and NaPCP in the aquatic and atmospheric compartment
1995 - IRG/WP 95-50040-06
PCP and NaPCP were studied for their aquatic toxicity on bacteria, microalgae and daphnids and for their behaviour in the atmospheric compartment with a climatic chamber. Results of aquatic toxicity bioassays showed that toxicity was higher at low pH. This can be explained by the pKa value of 4.7 of PCP and the higher concentration of the non dissociated form of the pesticide at more acidic pH. Vo...
P Marchal, P Vasseur, G Ozanne
A physiological role of the glyoxylate and TCA cycles in fruitbody formation of the coppertolerant brown-rot fungus Fomitopsis palustris
2002 - IRG/WP 02-10430
Changes in activity of the representative enzymes involved in biosynthesis of oxalic acid (oxalate) and carbon metabolism of glucose were investigated in relation to the fruit body formation of the copper-tolerant brown-rot fungus Fomitopsis palustris. Changes in specific activities of the two glyoxylate (GLOX) cycle key enzymes (isocitrate lyase (ICL) and malate synthase (MS)), the two oxalate-fo...
Jeong-Jun Yoon, T Hattori, M Shimada
The role of oxalic acid in short fiber formation by the brown-rot fungus Postia placenta
1993 - IRG/WP 93-10028
The mechanism by which brown-rot fungi depolymerize wood and cellulose remains a perplexing problem. Current evidence favors oxidation by low-molecular weight, non-enzymatic fungal metabolites. During attack of cotton cellulose by Postia placenta MAD-698, the degree of polymerization (DP) decreases to limit of degree of polymerization (LODP) over a period of 5-6 weeks with relatively low weight lo...
F Green III, J M Hackney, C A Clausen, M J Larsen, T L Highley
New Observations and Interpretation for Tunnelling Bacteria Decay
2006 - IRG/WP 06-10579
Decay micromorphology was studied systematically for diversely preservative treated Pinus radiata and Fagus sylvatica 20 x 20 x 500 mm stakes across 13 in-ground field test sites, during a 6.5 year exposure. Sites were selected to maximise occurrence of a diverse range of decay types. Micromorphology that suggested orientation of tunnelling bacteria with the cellulose microfibrils of the S2 and S1...
R Wakeling
The role of oxalic acid in tolerance to N’N-naphthaloylhydroxylamine in Tyromyces palustris
2006 - IRG/WP 06-10584
Certain wood decay fungi exhibit tolerance to one or more wood preservatives. Copper tolerance of brown-rot fungi has been studied in our laboratory for the past six years. We have observed some degree of tolerance to N’N-naphthaloylhydroxamine (NHA), a recently patented termite bait, by the brown-rot fungus Tyromyces palustris TYP-6137. In an effort to try and confirm this tolerance in other is...
R A Arango, C A Clausen, F Green III