Your search resulted in 197 documents. Displaying 25 entries per page.
Influence of acidification on decay processes of CCB treated wood
2004 - IRG/WP 04-10514
The phenomenon of copper tolerance by brown rot fungal strains has been known for a long period but the complete mechanism of copper tolerance by these fungi is not understood yet. Copper tolerance has previously been linked to oxalic acid excreted by copper tolerant brown rot fungal strains. This acid reacts with copper in the wood to form an insoluble and therefore less toxic copper oxalate. The...
M Humar, S A Amartey, M Šentjurc, F Pohleven
Old and new facts on the dry rot fungus Serpula lacrymans
1991 - IRG/WP 1470
The article collates some of the recent literature on the biology of the dry rot fungus Serpula lacrymans. The fungus can grow at 28°C, and maximum wood moisture is above 55%. Serpula Iacrymans degrades crystalline cellulose. The intensive production of extracellular oxalic acid is neutralized by calcium and iron. There is considerable variation among the strains with regard to factors such as gr...
O Schmidt, U Moreth-Kebernik
Properties of cellulose degraded by the brown rot fungus, Postia placenta
1988 - IRG/WP 1350
To gain further understanding of the nature of the cellulose depolymerizing agent or agents of brown-rot fungi, brown-rotted cellulose was chemically and physically characterized. Various culture conditions, such as low nitrogen and elevated oxygen levels, did not induce degradation of cellulose by Postia placenta in liquid cultures. Therefore, brown-rotted cellulose for analysis was prepared by a...
T L Highley, R E Ibach, T K Kirk
Experiments on the degradation of tributyltin oxide: A progress report
1984 - IRG/WP 3287
A variety of experiments designed to assess the chemical and physical factors affecting the degradation of tributyltin oxide in treated timber are described. Simple procedures in which temperature and oxygen availability were increased in the presence of wood and water suggest that the wood itself was of prime importance. Attempts to decrease degradation with antioxidants were unsuccessful but led...
R J Orsler, G E Holland
Practical experiments with Boracol 10 Rh used as a fungicide in the repair process after attack by the dry rot fungus (Serpula lacrymans)
1987 - IRG/WP 3458
The test is carried out in an old house in Nyhavn, Copenhagen. The roof and the walls close to were heavily attacked by dry rot fungus (Serpula lacrymans) because damage to the zinc covering the frontspice were letting in water to the wood and wall construction. An attack by the dry rot fungus is more complicated to repair compared with other wood destroying fungi because beside the damage on wood...
J Bech-Andersen
A possible role of unique TCA cycles in wood-rotting basidiomycetes
2003 - IRG/WP 03-10461
The copper tolerant brown-rot fungus, Fomitopsis palustris, acquires metabolic energy by use of the constitutively-occurring Kornberg’s glyoxylate cycle coordinating with oxalate biosynthesis and glucose oxidation (Erman Munir et al. Proc. Natl. Acad. Sci. USA, (2001) 98, 11126-11130). Furthermore, this fungus does not have the normal TCA cycle, lacking 2-oxoglutarate dehydrogenase which is a ke...
E Munir, T Hattori, M Shimada
The lasting dehydration of wood treated by bifluorides worked up in Diffusec noticed by a continual drying of the wood
1999 - IRG/WP 99-30196
After an immersion of sound wood in a solution of Diffusec, in which a combination of acid potassium and ammonium bifluorides = FHF- in dissociated form is present, their potassium and ammonium fluoride ions together with the bifluoride ion = (FHF-) diffuse into the wood. They make use of the woodmoisture available as O-H-O bonds directly attached to the cellulose in the wood fibres to attract the...
H F M Nijman
Production, function and neutralization of oxalic acid produced by the dry rot fungus and other brown rot fungi
1987 - IRG/WP 1330
The formation of oxalic acid by the wood-destroying fungi causing brown rot, is found to be the key which by hydrolysing the hemicellulose brings the cellulose in the tracheid wall in contact with the cellulase enzymes and yeld watersoluble sugars leaving only a lignin skeleton. To control the pH in the substrate the excess oxalic acid is precipitated to water insoluble calcium oxalate by the dry ...
J Bech-Andersen
The effect of acid rain on CCA treated timber
1990 - IRG/WP 3579
The effect of acid precipitation on the leaching of copper, chromium and arsenic from timber treated with different CCA preservatives was studied in the presence of three types of soil under simulated field conditions. Pine sapwood, embedded in soil, was subjected to simulated rainfall at three different levels of acidity. The CCA preservative formulations tested were:- American Wood Preservers&am...
R J Murphy, D J Dickinson
Hydrolysis of bordered pits during colonization of conifers by brown-rot fungi
1995 - IRG/WP 95-10103
Brown-rot decay results in rapid reduction in degree of polymerization (DP) of holocellulose with concomitant strength loss (MOR) without removing lignin. Development of new methods of wood protection will require focusing on early events in the sequence of depolymerization. Bordered pit membranes (sapwood) represent a readily available source of non-lignified carbohydrate, ie. pectin and cellulos...
F Green III, J L Tschernitz, T A Kuster, T L Highley
Biological degradation resistance of wood acetylated with thioacetic acid
1983 - IRG/WP 3223
Chemically, modification of wood is being considered as an alternative to conventional preservation by toxic chemicals. Acetylated wood has been reported to be quite resistant to most biodegrading organisms at weight percent gains (WPG) around 15-19. The conventional acetylation techniques with acethic anhyrdride result in generation of acetic acid. However, acetylation with thioacetic acid overco...
S Kumar, S C Agarwal
An anti-termite formulation for soil treatment with natural products and its efficacy against Coptotermes formosanus Shiraki
2003 - IRG/WP 03-30319
An anti-termite formulation of an environmental conservation type for soil treatment was developed. The formulation was composed of decanoic acid (n-capric acid, an fatty acid derived from coconut oil with ten carbons) as an active ingredient and other natural products. Experiments to examine the efficacy of the formulation against Coptotermes formosanus Shiraki were conducted at the termite field...
S Yoshida, T Nakagaki, A Igarashi, A Enoki
Oxalic acid metabolism of Postia placenta
1992 - IRG/WP 92-1566
The oxalic acid metabolism of Postia placenta was studied in liquid culture in order to identify the metabolic pathways of biosynthesis and to determine whether oxalic acid physiology could be correlated with efficiency in wood decay. Oxalic acid production was determined for test strain MAD698 grown in a basal defined medium with a variety of different carbohydrate and nitrogen sources. The highe...
J A Micales
Serpula lacrymans the dry rot fungus. Revue on previous papers
1989 - IRG/WP 1393
It is found that the Dry rot fungus Serpula lacrymans grows in houses only because of its need for basic materials to neutralize the oxalic acid production or heavy metals which celate the oxalic acid. The average distance from the mycelium to the basic materials is found in average to be 14.2 cm with a variation from 0-100 cm. In contrast to Serpula lacrymans the Coniophora puteana and the Rigido...
J Bech-Andersen
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
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
Performance of Copper-Chrome-Arsenic (CCA) and Copper-Chrome-Boric (CCB) treated panels of Bombax ceiba and Paraserianthus falcataria against bio-deterioration at Krishnapatnam harbour, east coast of India
2003 - IRG/WP 03-30310
Results of investigations on the durability of light weight timber species (Specific gravity below 0.4) i.e., Bombax ceiba and Paraserianthus falcataria in treated and untreated condition conducted at Krishnapatnam harbour (Lat 13o28’ to 13o59’ N; Long: 80o10’ to 80o16’E) along the east coast of India are reported in the paper. Exposure trails were conducted with panels (Size: 30 x 3.8 x...
B Tarakanadha, N R Raveendra Prasad, K S Rao
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
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
CCA removal from treated wood by chemical, mechanical and microbial processing
1998 - IRG/WP 98-50101-26
Most preservative-treated wood produced and consumed in the U.S. is treated with toxic inorganic compounds containing copper, chromium, and arsenic. Because chromated copper arsenate (CCA) is fixed to the wood, treated wood has not been considered toxic or hazardous and is currently landfilled. Increasing public concern about environmental contamination from treated wood combined with increasing q...
C A Clausen, R L Smith
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
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