Your search resulted in 751 documents. Displaying 25 entries per page.
Borates and their biological applications
1998 - IRG/WP 98-30178
This paper reviews some of the many biological applications of borates. Boron is a ubiquitous element found widely distributed in the environment and is a normal component of a healthy diet. Elemental boron does not exist in nature, but is always found combined with oxygen in compounds called borates. Boron is an essential micronutrient for plants, and there is evidence to suggest that boron is of...
J D Lloyd
Protecting wooden structures
1980 - IRG/WP 392
Chromium-containing chemicals that effectively retard weathering of wood improve performance of subsequently applied finishes. Current work is focusing on the performance of wood-derived products (plywood, hardboard, fiberboard, particle board) after surface treatment with inorganic chemicals. The overall objective of the continuing research is to investigate new environmentally safe procedures to...
W C Feist
A field test with Benzotar, an industrial residue, as a wood preservative
1985 - IRG/WP 3349
Benzotar, a residue of production of benzoic acid, was tested in field as a wood preservative. Results, after 6.5 years of exposure, showed that this product presents properties that improve the performance of wood in ground contact. This paper describes these results and presents a discussion an some aspects of its potential utilization in Brazil....
S Milano, L R Silva
Antifungal mechanism of dichloro-N-octylisothiazolone
1998 - IRG/WP 98-30183
4,5-dichloro-N-octylisothiazolin-3-one (DCOI) is a member of the isothiazolone class of preservatives, whose antimicrobial mechanism of action has been intensively studied over the last decade. DCOI has also been intensively studied for use in wood preservation. The isothiazolones are electrophilic molecules that rapidly react with thiol groups to form covalently bonded isothiazolone-thiol adducts. This ability to bond with thiol groups is crucial to their ability to act as preservatives.
Thiol groups are present in proteins as part of the amino acid cysteine, where they play an important role in maintaining protein structure and function. A number of enzymes have thiol groups at the site where the enzyme function is performed, and these thiol groups may participate in the enzyme reaction. If the isothiazolone reacts with this thiol group, the activity of the enzyme is inhibited. Our studies have shown that there are several enzymes in the Krebs cycle that are inhibited by isothiazolones and these enzymes are required to generate energy and perform many biosynthetic functions. Reflective of this, DCOI has been shown to be a rapid inhibitor of cellular respiration, causing the cell to cease consuming oxygen almost immediately upon contact with DCOI. The multiplicity of targets and their central importance to the metabolism of the cell, as well as the fact that all microbes use at least parts of the Krebs cycle, can be related to the low use levels and broad spectrum of activity of DCOI.
The antimicrobial mechanism of DCOI results in a potent rapid-acting preservative with a broad spectrum of antifungal and antibacterial activity that is effective at low levels.
J S Chapman, M A Diehl, K B Fearnside, L E Leightley
Report on marine borer attack on some timbers treated with CCA wood preservative and exposed for three months in sea-water
1985 - IRG/WP 4112
Destruction of timbers by marine borers has long been a problem for the coastal population of Thailand. The use of heavy durable timbers with frequent maintenance, or total replacement, is the only solution for fishermen with their fishing craft or marine installations, meanwhile wharves or other large scale constructions are usually made by using concrete pilings or concrete casings. In recogniti...
A Rananand, W Yoosukh, U Sittiphuprasert
A fixation model, based on the temperature dependence of CCA-C fixation
2000 - IRG/WP 00-40163
A model was prepared for the fixation of 1% CCA-C in red pine that allows the prediction of extent of fixation based on the temperature history of the treated wood following pressure treatment. The reaction kinetics of the rapid initial reaction and the slower main reaction were characterized using the Van t'Hoff equation. The initial reaction could be represented by a 10th order chemical...
P A Cooper, K M F Kazi, Jianbin Chen, Y T Ung
Checking of sodium pentachlorophenate fixation in wood
1990 - IRG/WP 3620
In order to estimate the volatilization of sodium pentachlorophenate from treated wood, wood samples treated with pentachlorophenate were analysed after various durations of an EN 73 weathering The results giving no clear evidence of volatilization, treated wood samples were put in a test chamber with precise climatic conditions, the air used in the experiment being analysed. The pentachlorophenat...
M Lamour, H Sageot
CCA fixation experiments. Part 2
1989 - IRG/WP 3505
CCA fixation in wood was measured by both squeezing solution from treated wood that had not been dried and analyzing the solution for copper, chromium and arsenic, as well as using a chromotropic acid test to detect the presence of chromium VI. Both methods provide useful information on the CCA fixation process and illustrate that chromium VI disappears as CCA becomes fixed within wood....
W S McNamara
Copper naphthenate-treated Southern Pine pole stubs in field exposure. -Part 2: Chemical characterization of full size pole stubs 12 years after treatment
2000 - IRG/WP 00-30246
This study examines the influence of pre-treatment and post-treatment steaming on the character and physio-chemical nature of copper naphthenate in hydrocarbon solvent treated pine in larger, pole diameter, pole stub-length samples. This work is the continuation of two projects that began almost a decade ago. Previous reports indicated that certain morphological changes might occur in small labora...
H M Barnes, D P Kamdem, M H Freeman
Diffusion of bifluorides and borates from preservative rods in laminated beams
1991 - IRG/WP 3644
Laminated beams from spruce, pine and larch were treated with two preservative rods, based on bifluorides and octaborate respectively. After 3 and 6 months placed in different climates (65% r.h., 100% r.h., water) the diffusion of the active ingredient was measured. After the 6 months period, the diffusion of the bifluorides was, in all species, ca. 5 times larger than the diffusion from octaborat...
H Militz
Copper based water-borne preservatives: The biological performance of wood treated with various formulations
1987 - IRG/WP 3451
Wood samples treated with the various components of CCA preservative singly and in combination were tested against a soft rot organism, a copper tolerant brown rot organism and in soil burial both unleached and after leaching. The results suggest that, of the elements tested, fixed copper is essential for preventing soft rot attack and fixed arsenic is essential for preventing attack by a copper t...
S M Gray, D J Dickinson
Evaluation of the leach resistance and preservative efficacy of novel biocides as surface treatments applied by brush to spruce (Picea abies)
1998 - IRG/WP 98-30170
The comparative leach resistance and preservative efficacy of a number of alternative organic preservatives (available from Zeneca Specialties) and selected commercially available biocides as surface coatings to wood in Hazard Class 3 have been assessed. Two concentrations of test preservatives were applied by brush to Spruce (Picea abies), including formulation and untreated controls. A leaching ...
I M Tierney, A Bruce, D C R Sinclair, T Yeates
In ground contact field trial results of preservative treated incised and unincised spruce
1996 - IRG/WP 96-40076
Field trials of treated spruce stakes have been demonstrated that incising the stake before treatment improves the preservative uptake both for CCA and creosote. This results in a substantially extended service life for the incised stakes over the unincised stakes for preservative concentrations at commercial levels. After 24 years in ground contact the majority of incised spruce samples are sound...
E D Suttie
Standardisation of tests of toxicity of preservatives to soft rot fungi
1978 - IRG/WP 2119
J G Savory
36 years of wood preservative tests in Tanzania
1992 - IRG/WP 92-3731
The performanee of major wood presevatives which are used widely commereially are given. These include creosote, CCA's and 5% Pentachlorophenol dissolved in heavy industrial diesel. Tests are conducted at three ecologically different using pine stakes. Results show that the striking performance of creosote and CCA's is noticeable at above 128 kg/m³ and 16 kg/m³ respectively....
K K Murira, P F Nangawe
A method of predicting the average life of field tests on preservative-treated stakes
1977 - IRG/WP 297
The paper presents an analysis of the results of completed field stake tests on untreated and preserved timber, and develops a method of predicting the average life of incomplete stake tests on wood preservatives from the failures that have occurred so far....
D F Purslow
Lignin-copper, a new wood preservative without arsenic and chromium
1992 - IRG/WP 92-3702
A more environmentally sound treatment for wood with preservatives containing no arsenic or chromium, has been developed and studied on a laboratory scale. The method involves a first step impregnation with an aqueous solution containing modified, water-soluble kraft lignin followed by a second step involving impregnation with a copper salt solution to give fixation of the lignin into a water-inso...
B Ohlsson, R Simonson
The variation in electrical resistance in the CCA-treated wood during the fixation
1989 - IRG/WP 3554
The curve commonly used in Scandinavia for describing the fixation period at different temperatures for CCA-impregnated wood is based on investigation by Dahlgren on the pH-variations in a mixture of sawdust and preservative solution. As far as we know there is no such investigation on solid wood. We have therefore measured the electrical resistance in CCA-treated solid wood to see if this will di...
F G Evans, B Nossen
Thirty-four year test of on-site preservative treatments to control decay in wood above ground
1993 - IRG/WP 93-30015
This research was initiated in 1958 to investigate efficacy of various preservatives and treating methods for new lumber going into exterior structures of buildings. Post-rail units (2x4 inches) constructed of Southern Pine sapwood, Douglas-fir heartwood, and mill run western hemlock were dip- or brush-treated before or after assembly. Units were trested with pentachlorophenol in various petroleum...
T L Highley, T C Scheffer
Termite field test results of preservative treated and modified woods in Kumamoto, Japan
2001 - IRG/WP 01-30275
Various preservative treated or modified wood stakes other than CCA, were buried in the soil, maximum for six years in Kumamoto, south west side of Japan. In this area, two main termite species, Coptotermes formosanus and Reticulitermes speratus, are distributed. After two years in field, untreated sapwood of sugi (Cryptomeria japonica) were observed severe attacks by termites, but the preservativ...
K Suzuki
Copper binding capacity of modified wood flour
1992 - IRG/WP 92-3709
Wood flour was modified by reaction with oxidising agents and CCA preservative. The copper chromium and arsenic were removed from the CCA treated wood flour by an acid leaching procedure. The modified wood flours were allowed to react with copper acetate solution and the level of copper fixation achieved was determined. The modified wood flours had greater affinity for copper ions present in solut...
N C Milowych, W B Banks, J A Cornfield
HCB - a new preservative combination for wood pole maintenance
1996 - IRG/WP 96-30122
New combination of heavy creosoted boron (HCB) applied on hardwood and softwood logs at different moisture content revealed successful diffusion of boron in all sapwoods within 7 days and in all sapwoods plus hardwoods within 15 days. The new cost effective paste sterilizes wood through diffusion and suitable for pole maintenance at groundline and above groundline e.g. cut ends, drilled holes, woo...
A K Lahiry
Preservative treatment of Pinus elliottii
1987 - IRG/WP 3435
The treatment of Pinus elliottii with copper-chrome-arsenic preservative by four alternative seasoning and treatment methods is investigated. Steam conditioning followed by either alternating pressure method (APM) or 'Q' treatment resulted in inadequate preservative penetration. Air drying or high temperature drying followed by the Bethell process resulted in a high standard of t...
P Vinden, L Carter
Adequate preservative treatment of tropical and subtropical hardwoods for electric anchor logs
1997 - IRG/WP 97-40101
Most available 27 different hardwood species grown in Bangladesh was investigated regarding suitability as CCA-C (chromated copper arsenate type-C) impregnated anchor logs for rural electrification programme. The kiln-drying properties, sapwood thicknesses, CCA treatability grades of sapwood and heartwood, natural durability of heartwood and CCA retainability at specific assay zone separated 27 ha...
A K Lahiry
The microbiological treatment of chlorophenolic preservative in spent utility poles
1993 - IRG/WP 93-50001-24
The number of pentachlorophenol (PCP) treated poles being removed from service is increasing, but disposal options for this material are limited. Biological Degradation of the preservatives in spent poles, before disposal or reuse, offers a promising technique. The reduction of PCP in treated timber, after inoculation with PCP-degrading bacterial species, Rhodococcus chlorophenolicus and Flavobact...
A McBain, F Cui, J N R Ruddick