Your search resulted in 199 documents. Displaying 25 entries per page.
A quantitative weathering study of wood surfaces modified by chromium VI and iron III compounds
1989 - IRG/WP 2330
Thin veneers of Pinus radiata were treated with dilute aqueous solutions of chromium VI and iron III compounds and exposed to natural weathering for 35 days. Zero-span tensile strength and weight losses of treated veneers were compared with losses observed in untreated specimens In a study designed to demonstrate the applicability of strength and weight loss measurements to the rapid quantitative ...
P D Evans, K J Schmalzl
Relationship between the bending strength and the degree of termite attacks on western hemlock by Coptotermes formosanus Shiraki
1990 - IRG/WP 1434
For the examination of the relationship between the bending strength and the degree of termite attacks, Western Hemlock (Tsuga heterophylla Sarg.) was used. Sixty specimens (4.5 x 4.5 x 82 cm³) were attacked by termites at the culture room of Coptotermes formosanus Shiraki. The termites were introduced on the central parts (10 cm) of specimens. In the case of the 2 points loading, the bending mom...
K Suzuki, T Tanaka
Protection of pile tops using combinations of internal treatments and water shedding caps
1993 - IRG/WP 93-30020
Preservative treatment produces an excellent barrier against fungal, insect, and marine borer attack; however, fabricators often disrupt this barrier during construction, creating avenues for entry of decay agents. This problem is particularly acute in marinas along the coastal United States. Standards recommend the application of a water-shedding cap at the time of installation to prevent pile to...
P Schnieder, M A Newbill, J J Morrell
Nondestructive assessment of biodegradation in southern pine sapwood exposed to attack by natural populations of decay fungi and subterranean termites
1994 - IRG/WP 94-20042
Field methods for evaluating decay resistance of experimentally treated materials lack a means for quantitative measurement of residual strength. Quantitative relationships between speed of impact-induced waves travelling parallel to the grain and residual compressive strength have been demonstrated in softwood attacked by brown rot-decay fungi, but the effects of termites have not been documented...
R C De Groot, R J Ross, W Nelson
Studies and experiences of occurrence and development of soft rot in salt-treated poles of pine (Pinus sylvestris) installed in Swedish transmission lines in the years 1940-1945
1977 - IRG/WP 277
The present work describes the result of microscopic examinations of some 2,000 borings extracted from 20 to 23-year-old salt-treated poles (Scots pine) from the southern and central parts of Sweden. The purpose was to map out the occurrence of soft rot in Sweden and its influence on the mechanical strength of the poles as well as to contribute to the development of new and more satisfactory metho...
H Friis-Hansen
Biodetioration and strength reductions in preservative treated aspen waferboard
1983 - IRG/WP 2195
Experimental aspen waferboards, bonded with liquid or powdered phenol formaldehyde resins and treated by various methods with a wide selection of preservatives, were tested for fungal resistance in accelerated laboratory trials. Mold growth on the surface as well as weight and strength losses due to the actions of decay fungi were determined. Testing of board strength after decay in high and moder...
E L Schmidt, H J Hall, R O Gertjejansen, R C De Groot
A comparison of the diffusion of boron from two types of solid preservative rods into the heartwood of 3 Eucalypt pole species
2000 - IRG/WP 00-30227
The ability of boron to diffuse from polyborate and boron/fluoride rods through the heartwood of three eucalypt pole species (blackbutt, red ironbark and spotted gum) was examined. The aim was simply to determine the effects of rod type, wood species and time on the longitudinal diffusion of boron in eucalypt heartwood. Rapid diffusion of boron from polyborate or boron/fluoride preservative rods o...
P J Beutel, P D Evans
Three years of field tests with "Lignomer" stakes in ground contact
1981 - IRG/WP 3166
The "Lignomer" (Wood Polymer Composite) is a material obtained during the polymerisation of various monomers or its mixtures in wood. As laboratory tests have shown, this material is characterized by a high resistance against biological deteriorating agents. The laboratory investigations on the durability of various materials against biological deterioration are in many instances extended by field...
K Lutomski
Laser incising of spruce lumber for improved preservative penetration
1991 - IRG/WP 3646
Red spruce heartwood specimens were incised using a range of laser beam power levels and pulse durations. The penetration of CCA through these holes into the wood was monitored after pressure treatment. In addition, green and dried spruce samples were incised using two patterns with incision densities of either 16.1 holes/in² or 21.3 holes/in². Following CCA pressure treatment the samples were t...
B Goodell, F A Kamke, Jing Liu
Internal pressure development in Douglas fir lumber during pressure treatment
1997 - IRG/WP 97-40091
Preservative treatment of Douglas fir lumber to meet current industry standards poses a major challenge and a variety of methods have been developed to overcome these problems. One aspect for treatment improvement that has received less attention is the relative effect of treatment parameters on changes in pressure within the wood. Previous studies of spruce and radiata pine suggest that internal ...
P F Schneider, J J Morrell
Biological control of internal decay in Scots pine poles: A seven year experiment
1992 - IRG/WP 92-1529
The interactions between key fungi were monitored, by non-destructive and destructive sampling methods, during the course of an experiment on the effectiveness of Scytalidium sp. and Trichoderma spp. for eliminating established infections of Lentinus lepideus (Fr. ex Fr.) Fr. in creosoted Pinus sylvestris poles. Although extensively isolated at the beginning and end of the experiment, Trichoderma ...
P I Morris, D J Dickinson, B Calver
Changes in some important mechanical and physical properties of untreated and treated mining timber after exposure to the conditions of a colliery
1996 - IRG/WP 96-20082
Each of salt treated and untreated mining timber (wedge) pairs with 5x15 cm² cross-section and 155 cm length prepared from Scots pine, Bornmüller's fir and oriental beech was cut in the small standard test specimens to determine changes in some important mechanical and physical properties, 13 month after exposure to the conditions of Kozlu Hard Coal Mines in the depth of 52 m. Thus, the...
A Bobat
Bending strength of heat-treated spruce and pine timber
2002 - IRG/WP 02-40242
Heat-treatment of spruce (Picea abies) and pine (Pinus sylvestris) beams (45 x 145 mm) gave a reduction in bending strength of approximately 50%. The bending stiffness (modulus of elasticity) only decreased by 3.5%. Tests were carried out according to EN 408. Another effect of the heat-treatment was increased variation in bending strength. The 5th percentile value of the bending strength, the so c...
C Bengtsson, J Jermer, F Brem
Evaluation of a laboratory soft rot test on basis of weight loss and residual strength
1989 - IRG/WP 2336
Based on the principles of different previously reported experimental procedures dealing with laboratory soft rot testing, a study was conducted on treated poplar and beech. Preservatives used were CCA, CCF, AAC, Azaconazole and TCMTB. Treated samples were exposed for three months in a vermiculite substrate to Chaetomium globosum. Evaluation was based on absolute mass loss, percentage weight loss ...
W Verbeke, J Van Acker, M Stevens
A new factory applied preservative treatment for joinery
2002 - IRG/WP 02-40246
Conventional pre-treatment processes involve the principle of applying preservatives to the external surfaces of wood to achieve the necessary penetration and retention of the chemicals although the heartwood remains difficult to treat.
The present development involves the production of internal reservoirs within new joinery components, which are subsequently filled with a specially developed g...
I M Robertson, W Beauford
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. Previou...
G Oberdorfer, P E Humphrey, R J Leichti, J J Morrell
The potential use of impregnated coconut wood for power line poles in rural areas of Java
1980 - IRG/WP 3130
Electrification of rural areas in Java needs thousands of power line poles which are relatively cheap in price, but have adequate strength and are fairly durable. A choice of wood species is available in the country. One alternative is coconut wood found in abundance in the villages. This may give a solution to Java's needs since supplies are readily available almost everywhere. Based on ...
H Yudodibroto
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
Determination of toxicity data for preservatives against Basidiomycetes by measuring the reduction in compression strength of wood
1988 - IRG/WP 2297
Blocks of Pinus radiata D. Don were treated to 12 retention levels with CCA and NaPCP. These were exposed for 12 weeks in agar jars to the dry rot (brown rot) Serpula lacrymans (Schum. ex Fr.) S.F. Gray. After mass loss determination, the same blocks were tested for reduction in compression strength parallel to the grain. Using both these parameters, together with interpolated 6 week strength loss...
J Wazny, J D Thornton
Glue-line additives for protecting plywood. A review
1978 - IRG/WP 2102
The conclusions of this review are: 1) Insecticidal glue-line additives can be used satisfactorily to protect plywood against insect attack. 2) It is uncertain, in spite of some claims, wether fungicidal glue-line additives can be similarly used to protect plywood against fungi under damp conditiones. There is a need for further work to validate the mycological tests that may be used to investigat...
R Cockcroft
The effect of moisture content on the electrical resistance of timber as detected by a pulsed current reistance meter (Shigometer)
1984 - IRG/WP 2212
The literature concerning the use of the Shigometer® for detecting decay in standing trees and wood poles is reviewed and the differences of opinion over the effect of timber moisture content on electrical resistance are highlighted. A simple experiment designed to test this effect is described and the implications of the results for testing poles in service are discussed. There was a large diffe...
P I Morris, D J Dickinson
The effect of oil-borne preservative treatments on the shear strength of FRP/wood composite adhesive bonds
2003 - IRG/WP 03-40265
Reinforcement of structural wood components with Fiber Reinforced Polymer (FRP) will enhance the beam’s strength, but actual data on long-term durability is sparse, not well documented or not readily accessible. In this study, bond properties of FRP-wood composite materials were investigated following treatment with creosote or copper naphthenate preservatives. The properties investigated inclu...
B Herzog, B Goodell, R Lopez-Anido
Supply of wooden transmission and telephone poles in Tanzania: Problems and possible solutions
1987 - IRG/WP 3424
The eucalypts which have been used widely for utility poles for more than 30 years have dwindled remarkably from traditional supply areas. Consequently, pole-using authorities are considering importing poles from abroad. This alternative is considered unrealistic and costly. The aims of this paper are: - to dispel fears of pole scarcity and to show that an abundant resource of a variety of tree sp...
K K Murira, S A Diwani
Selecting fumigants for treatment of internal decay in wood
1986 - IRG/WP 3370
A number of potential fumigants were screened with respect to their toxicity to decay fungi, (Poria carbonica, and Lentinus lepideus) and their sorption characteristics on Douglas Fir (Pseudotsuga menziesii Mirb. Franco) wood. Wafers of infected wood were exposed to different fumigant concentrations for various times then cultured to determine viability. The lethal concentration X time (ct) factor...
P A Cooper
Examination of power poles by computerized tomography
1980 - IRG/WP 2142
The technique known as computed axial tomography (CAT or CT) has become widely known because of the success it has achieved in medical imaging and diagnostics. It has now been used to give non-destructive crosssectional pictures of a variety of industrial objects, including wooden power poles, with a spatial resolution of about 1 mm (0.04 in.). It is obvious the benefits that would be derived from...
J A Taylor, I L Morgan, H Ellinger