Your search resulted in 288 documents. Displaying 25 entries per page.
Strength loss associated with steam conditioning and boron treatment of radiata pine framing
1987 - IRG/WP 3438
The combined effect of included defects and wood moisture content on the strength loss of second rotation radiata pine framing following conventional steam conditioning is investigated. The green Modulus of Elasticity (MOE) is reduced by approximately 13% after steaming. When dried after steaming, however, neither the MOE nor MOR is significantly different from unsteamed dried controls....
M J Collins, P Vinden
The performance of wood preservatives in soil-bed soft rot tests
1993 - IRG/WP 93-20007
Testing the efficacy of wood preservatives in soil is recognised as a fundamental part of the assessment of long-term wood protection in ground contact. Laboratory based tests can provide a hazardous environment in which a preservative can be challenged by a range of micro-organisms. This paper presents the results of tests carried out to investigate the performance of wood preservatives in a wet ...
G R Williams, S Caswell
Airborne algae as a wood degradation factor
1992 - IRG/WP 92-1549
The occurrence of airborne (aerophytic) algae on wood is a very frequent phenomenon. However, there is currently a lack of information concerning their effect on the wood tissue. Some important genus of algae infesting wood under natural conditions are listed, as well as the results of experimental studies in the "in vitro" culture concerning the effect of two selected algal species on some physic...
K J Krajewski, J Wazny
Decrease of the antidecay resistance of beech wood treated with organotin fungicides after its natural ageing
1998 - IRG/WP 98-30185
The antidecay resistance of beech-wood samples (120 x 8.5 x 8.5 (MM)) treated with tributyltin fungicides gradually decreased due to prolongation of their natural ageing:
tributyltin fungicides (TBTO, TBTS, TBTCA, TBT-DEDTK were applied by pressure impregnation technique in ethanole solutions (c = 0. 1%, 0.33% or 1%);
treated beech-wood samples were naturally aged without their contact with grou...
L Reinprecht
Treatment of wood with formaldehyde. Acid catalysis of the reaction between formaldehyde and wood
1980 - IRG/WP 3146
Formaldehyde reacts with the free OH-groups in wood forming cross-linking bonds. The reaction can be brought about without any catalyst but in that case the activation energy is very high and high temperatures and long reaction times are needed. Normally, the reaction is catalysed by different acids. Acid catalysts, however, tend to degrade the cellulose and the wood matrix causing reduction in th...
T Vihavainen, K Piispanen, P Mansikkamäki
Microscopical analysis of formaldehyde-acid modified wood
1981 - IRG/WP 3182
Cross-linking of wood with gaseous formaldehyde improves its hygroscopic and dimensional behaviour, and its resistance against micro-organisms. However, formaldehyde cross-linking reactions take place only in the presence of an acid catalyst, which results in losses in mechanical By optimization of a formaldehyde-sulfur dioxide vapour phase process the reaction conditions were established to limit...
M Stevens, N Parameswaran
The effect of extent and location of decay on strength loss in constructional timber
1994 - IRG/WP 94-30039
Radiata pine heartwood billets, 50 x 100 x 1000 mm³ were end-sealed and treated with copper-chrome-arsenate preservative (NZ Type I) to a range of retentions and penetration patterns. Cross-sections, 10 mm thick, were cut from the centre of each billet and used for determination of preservative distribution, for preservative analysis and for decay tests. The decay test consisted of laying samples...
M E Hedley, H Bier
Application of a novel strength evaluation technique during screening of wood preservatives
1986 - IRG/WP 2262
The effectiveness of CCA and ACA in treated aspen mini stakes tested using a novel bag procedure, with unsterile soil fortified with Chaetomium globosum and Ceratocystis albida, is reported. Good agreement between toxic limits determined using the standard weight loss procedure, and those determined by the strength technique were found, with some indication that the strength loss method is more se...
J N R Ruddick
Rapid loss of lignin at wood surfaces during natural weathering
1992 - IRG/WP 92-2390
Thin veneers of radiata pine (Pinus radiata D. Don) were exposed to natural weathering over a period of 30 days. Incident UV radiation was monitored at the test site. FTIR internal reflectance spectroscopy was used to study the chemical changes taking place at the veneer surface during weathering. Spectra obtained show that after only 3 days exposure there was substantial delignification at veneer...
P D Evans, K J Schmalzl, A J Michell
The comparative resistance to fungi of the wood munika (Pinus heldreichii Christ.), fir (Abies alba Mill.) and spruce (Picea excelsa Poir.) compared with Pinus sylvestris L. and some physical and mechanical characteristics of munika
1981 - IRG/WP 1129
The munika (Pinus heldreichii Christ.) is situated primarily in the Balkans, and partially in the south of the Apenine peninsula. As an endemic species, with a very little annual increment, it has not been used enough as a timber for mechanical conversion up till now, although the oldest trees can grow to 27 m in height, with a diameter at breast height of about 60 cm. According to data of many Ba...
M Petrovic, M Miric
Use of compression strength loss for measuring decay in the soil block test
1996 - IRG/WP 96-20083
The possibility of using radial direction compression strength of wood, rather than mass loss, was evaluated for both a brown-rot fungus (Gloeophyllum trabeum) and white-rot fungus (Trametes versicolor). With untreated pine wafers (5 x 19 x 19 mm³ - l x r x t) exposed to Gloeophyllum trabeum in a soil block test for five days, the compression strength loss was nearly 50% compared to a 5% mass los...
D D Nicholas, Zhongwei Jin
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
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
Biological durabilityof cement-bonded particleboard
1997 - IRG/WP 97-20115
Cement-bonded particleboard (CBP) is a panel product manufactured from a combination of wood particle and cement with various ratio. The wood particle is used as reinforced material and the cement as an inorganic binder. Because of its many excellent properties, such as high weathering resistance, sound attenuation, and good acceptance for a range of surface treatments, CBP is widely used as a fac...
Qiao Wang, M Takahashi
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
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
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
Decay rates and strength and stiffness loss in foundation beams
1992 - IRG/WP 92-1563
The TNO Centre for Timber Research has executed an extensive research programme into the rate of decay in foundation beams, as a result of lowering of ground water tables. The aim of the research was to develop a method, predicting the decrease in strength and stiffness in beams, due to wood decay during drytime of foundation beams. With the calculated extremes in decay, the damage caused by local...
P Esser, H S Buitenkamp
A comparison analysis of eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray
1991 - IRG/WP 2362
Investigations were previously carried out to compare eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray (some used in various countries as standard test strains): FPRL 12C (England), FPRL 12E (Germany), Warsaw III (Poland), HFP 7802 (Japan), DFP 16508, 16509, 16521 and 16522 (Australia). Studies included growth rate and dry mass of mycelium, decay capacity, reduction of compression stre...
J Wazny, J D Thornton
Mechanical strength of wood from the Vasa shipwreck
2008 - IRG/WP 08-20381
Samples from three ancient ship wrecks (Vasa, Elefanten, and Gröne Jägaren) and recent oak samples as reference were examined with regard to mechanical strength using the high-energy multiple impact (HEMI) - test method, which delivers the resistance to impact milling (RIM) of a material. Adoption and optimisation of the test method for the particular sample size of the wooden drilling cores was...
A O Rapp, C Brischke, C R Welzbacher, T Nilsson, C Björdal
Impact of decay and blue stain causing fungi on the structural integrity of wood
2009 - IRG/WP 09-10699
The potential influence of diverse decay patterns caused by different brown rot provoking basidiomycetes on the structural integrity of wood was investigated. Additionally the potential impact of blue stain on the structural integrity was examined. Therefore decayed Norway spruce (Picea abies Karst.) specimens representing a wide range of mass loss, caused by four different brown-rot fungi and one...
C Brischke, C Welzbacher, T Huckfeldt, F Schuh
Degradation of wood veneers by Fenton’s reagents: effects of low molecular weight phenolic compounds on hydrogen peroxide decay and tensile strength loss
2009 - IRG/WP 09-20400
Pine wood (Pinus sylvestris) veneers strips were incubated in acetate buffer containing hydrogen peroxide and iron to mimic mechanisms of brown rot decay and assess the degradation of cellulose through analysis of the tensile properties of the decayed wood. The tensile properties of thin wood strips treated with Fenton system reagents or precursors were determined and correlated to weight loss as ...
Yanjun Xie, R Well, Zefang Xiao, B Goodell, J Jellison, H Militz, C Mai
Photostabilization of Wood with Higher Molecular Weight UV Absorbers
2010 - IRG/WP 10-30524
Higher molecular weight UV absorbers were created by reacting the epoxy-functionalized UV absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP) with maleic, phthalic or succinic anhydride. The ability of the UV absorbers to photostabilize wood was then examined. FTIR-spectroscopy confirmed that HEPBP reacted with phthalic anhydride to create a polyester that preserved the UV-absorbing benzop...
P D Evans, M J Chowdhury
Preliminary Observations of the Photostabilization of Wood Surfaces with Cerium Oxide Nanoparticles
2010 - IRG/WP 10-40504
Reactive transition metal compounds, wood modification and grafting of UV absorbers have all been used to photostabilize wood. Some of these approaches are promising, but the toxicity of certain reactive transition metal compounds and the cost of wood modification and grafting have restricted their commercial applications. Hence, more cost-effective and environmentally friendly methods of protecti...
Chunling Liu, A Ahniyaz, P Evans