Your search resulted in 229 documents. Displaying 25 entries per page.
Determining the natural durability on xylarium samples: mini-block test, wood powder and chemical profiling
2019 - IRG/WP 19-10944
Xylaria, or wood collections, can be considered sleeping beauties in terms of wood technological and biological output. In this study we focus on determining the natural durability of xylarium specimens from the Federal Xylarium in the Royal Museum for Central Africa. The Federal Xylarium contains over 80,000 specimens, covering more than 13,000 species, mainly from Central Africa. These specimens have a random format (disks, book-shapes…) and should be treated with care when sampling for testing, as these specimens are not only limited in size, but also have a significant historical and cultural value. This makes it impossible in most cases to retrieve standard specimen dimensions as required according to CEN/TS 15083-1 (2005). To gain information on the natural durability of these xylarium specimens, two tests were performed: a mini-block test similar to the test described by Bravery (1978) and an indirect assessment using chemical fingerprints. In total 1112 mini-block samples were prepared from 577 xylarium specimens, covering 33 tropical species and complemented with 545 reference specimen, covering 11 species for benchmarking. The natural durability of the wood samples was assessed using the white-rot fungus Trametes versicolor. Beech wood was included as a reference to check whether the fungus was sufficiently virulent. The resulting natural durability classes per species of the mini-block test are similar to those found in common literature. Erythropheum suaveolens and Millettia laurentii appear highly durable, while Pycnanthus angolensis and Terminalia superba performed worst. Chemical fingerprints for the xylarium test specimen were obtained using Direct Analysis in Real Time – Time of Flight Mass Spectrometry (DART TOFMS). Several ions/molecules appear to be correlated with natural durability, showing the potential towards quick screening of the natural durability potential of a certain specimen/species
V Deklerck, L De Ligne, J Van den Bulcke, E Espinoza, H Beeckman, J Van Acker
Biological screening assays of wood samples treated with creosote plus chemical additives exposed to Limnoria tripunctata
1980 - IRG/WP 408
Laboratory methods for exposure of treated wood coupons to Limnoria tripunctata are described. Chemical additions to creosote were screened using this method. Three pesticides, Endrin, Kepone, and Malathion proved particularly effective. The addition of varying percentages of naphthalene to creosote using several treatment methods are currently being assayed. Results to date show that the coupons treated by the empty cell method have better performance than those prepared by the toluene dilution method. The naphthalene coupons treated by the full cell method show no attack after six months' exposure.
B R Richards, D A Webb
The effect of certain wood extractives on the growth of marine micro-organisms
1977 - IRG/WP 438
S E J Furtado, E B G Jones, J D Bultman
Results of chemical analyses in the field of wood preservation in the Bundesanstalt für Materialprüfung
1973 - IRG/WP 321
The results of qualitative and quantitative chemical analyses of wood preservatives are often the basis for evaluating the various works in the field of wood preservation. In the past 10 to 15 years a number of such works was carried out in the Bundesanstalt fur Materialprüfung, Berlin-Dahlem, dealing with the identification and effectiveness of wood preservatives and with methods of wood preservation. Fundamental realisations were made which will be summarised below. It seems advisable to differentiate between inorganic and organic chemical wood preservatives and methods of analyses. These are two distinct fields which differ also with regard to the analytical techniques applied.
H J Petrowitz
The decay resistance of chemically modified aspen composites to the white rot fungus Coriolus versicolor (L.) Quelet
1998 - IRG/WP 98-40122
Chemical modification of Aspen wood (Populus tremula L.) in the form of solid wood, veneers and sawdust was undertaken by a two step procedure consisting of esterification with maleic anhydride (MA) and subsequent oligoesterification with MA and glycidyl methacrylate (GMA) or allyl glycidyl ether (AGE). Modified wood was thermoplastic and was thermally formed by hot-pressing to produce veneer or solid wood samples with smooth glossy surfaces, while plastic-like wafers were obtained by hotpressing modified sawdust. Chemical modification alone was shown to enhance the biological resistance of Aspen to decay by Coriolus versicolor. In addition, hot-pressing enhanced decay resistance of both unmodified wood and esterified wood veneer samples, although no improvement was found by hot pressing oligoesterified wood. The most effective treatment for the improvement of decay resistance was chemical modification of the sawdust in conjunction with hot-pressing. A microscopic examination of chemically modified and control samples following exposure to the fungus showed more extensive colonisation and decay in untreated, unpressed samples.
M C Timar, A J Pitman, M D Mihai
Chemical compounds from Eperua falcata and Eperua grandiflora heartwood and their biological activities against wood destroying fungus (Coriolus versicolor)
2005 - IRG/WP 05-30373
The chemistry analysis of the compounds present in dichloromethane and ethanolic fraction as well as bioassays enables to understand the durability differences of Eperua falcata and Eperua grandiflora. The principal distinction between these two species is the acidic subfraction of diterpenoic extract, which is antifungic in Eperua falcata when tested in in-vitro conditions. This study also enables to show that ethanolic fraction plays an important role in the mechanism of natural durability. It also reports the first isolation of cativic acid in Eperua falcata wood.
N Amusant, C Moretti, B Richard, E Prost, J M Nuzillard, M-F Thévenon
Protocol for evaluation and approving new wood preservative
1985 - IRG/WP 2159
M E Hedley, J A Butcher
Di-sodium fluorophosphate, a new fluorine containing, water-borne wood preservative
1986 - IRG/WP 3373
The physical, chemical properties of Di-sodiumfluorophosphate (Na2PO3F) are compared with those of a trade-mark SF-salt. The opposition of biological activity and toxicological data showed that Di-sodiumfluorophosphate may be a suitable alternative to SF-salts ( based on MgSiF6).
D Seepe, W Metzner
Discussion of diiodomethyl p-tolyl sulfone (Amical® 48) as a fungicide for wood preservatio
1987 - IRG/WP 3425
The effectiveness of diiodomethyl-p-tolyl sulfone (Amical® 48) as a fungicide for preservation of wood is supported by a discussion of results from the literature and current research programs.
J M Stamm, K J Littel, F M H Casati, M B Friedman
Preliminary results of investigations on screening test of chemical compounds suitable for the preservation of lignocellulosic materials against biodeterioration
1976 - IRG/WP 262
This paper investigates the possibilities of reducing the time needed for the determination of the effectiveness of chemical compounds from the point of view of their eventual application to lignocellulosic materials for preservation against decay and soft-rot.
K Lutomski, S S Neyman
Contribution to study of the degradation caused in Pinus spp. poles used in field test
1989 - IRG/WP 1417
The study of the degradation produced by soil natural microflora on wood in contact with it in the field, has been going on for several years now. Our contribution to this aim in the present work has dealt with the possible relationship of the microorganisms in the soil. The microscopic visualization of wood colonization by the microorganisms, and the chemical analysis of the degraded wood compared with the undergraded.
M T De Troya, A Garcia, M J Pozuelo, A M Navarrete, A Cabanas
Efficacy of anhydrides as wood protection chemicals - II. Performance against soft rot fungi
1998 - IRG/WP 98-30174
Pine sapwood modified with various anhydrides and with butyl isocyanate was tested for its resistance to soft rot decay. Small stakes were exposed for 20 months in unsterile soil in a fungal cellar test. Wood modified with butyl isocyanate performed better than any of the anhydrides tested, with a threshold level of protection (less than 3% weight loss) at 12% weight percent gain (WPG). Stakes acetylated to 15% WPG did not give complete protection against soft rot. Stakes modified with alkenyl succinic anhydride showed increasing resistance to soft rot with WPG up to about 10% WPG, above which no further improvements were evident. Succinic anhydride and phthalic anhydride treated stakes showed little or no noticeable protection.
S C Forster, M D C Hale, G R Williams
Electron microscopic detection and chemical analysis of three-lamellar structures in wood-destroying fungi
1984 - IRG/WP 1240
In the course of transmission electron microscopical investigations of pine wood decay by various brown- and white-rot fungi extracellular three-lamellar structures (TLS) formed by the fungi were found in specimens stained with ruthenium red. These structures occured in the lumen of the wood cell surrounding the hypha at the outermost layer of the fungal cell wall. In the course of the investigations these structures were also detected in fungi cultivated with glucose on a rotary shaker, where they showed forms similar to tubuli and vesicles. The three-lamellar structures formed by the white-rot fungus Sporotrichum pulverulentum, which were contained in the outermost cell wall layer, were isolated by disintegration of the fungal pellet and subsequent digestion of the fungal cell wall by snail enzyme. It was found that these structures are resistant to the enzymatic digestion and are composed of 80 to 90% carbohydrates, mainly consisting of glucose monomeres, 5 to 10% proteins, containing 5 fractions with molecular weights between 30000 and 200000, and finally 5 to 10% lipids which do not contain any phospholipid.
R Foisner, K Messner, H Stachelberger, M Röhr
Nitrogen content of soils at field sites
1981 - IRG/WP 1133
Nine participants in the Collaborative Field Experiment submitted samples for nitrogen analysis to this laboratory as requested by Leightley (IRG/WP/3162). These arrived in a variety of conditions e.g. wet, dried, sterilised and unsterilised and sometimes spent a considerable time in transit. Soils varied in cellular fraction organic matter content, some were obviously sieved prior to postage while others contained significant quantities of large vegetative detritus. Samples were also taken at different times of the year and seasonal and climatic factors may have influenced the values subsequently obtained by analysis.
B King, G Mowe
Decay patterns observed in butylene oxide modified ponderosa pine attacked by Fomitopsis pinicola
1983 - IRG/WP 1183
Small blocks of ponderosa pine chemically modified by butylene oxide to three different weight percent gains (WPG) were decayed for 2 months with the brown rot fungus Fomitopsis pinicola. Wood substance loss and the type of decay pattern recognised were fairly similar both for control and blocks treated to 8 and 15 WPG. No difference in attack was observed between radial or tangential walls in latewood tracheids. Microscopical examination of undecayed wood blocks treated to 23.7 WPG revealed numerous cracks in both the middle lamella regions of radial walls and in cell corners of latewood tracheids. The fungus had gained entry to the cracks, possibly via bordered pits and rays. Attack started from the cracks and progressed along the middle lamella and towards the cell lumen.
T Nilsson, R M Rowell
United States Federal Committee on Wood Protection
1971 - IRG/WP 43
A C Jewett
Collaborative soft rot tests: Results of analyses of soil samples
1976 - IRG/WP 263
C R Levy
Biological and chemical observation on the early fungal colonization of TBTO treated Swedish redwood stakes
1984 - IRG/WP 3311
Data on the early fungal colonization of Swedish redwood stakes, impregnated with 1% TBT0 / 0.5% dieldrin solution, both by double vacuum impregnation and immersion processes are presented. Results of chemical analyses of wood samples from the outer 1 mm of separate painted and unpainted stakes, exposed over the same twelve month period, are also discussed.
R Hill, A H Chapman, A Samuel, K Manners, G Morton
Chlorodioxines dans le pentachlorophénol
1975 - IRG/WP 346
Chemical investigation of 23-year-old CDDC treated southern yellow pine
1997 - IRG/WP 97-30141
The effect of 23 years exterior exposure on CDDC treated southern yellow pine was evaluated by the application of solid state analytical instrumentation. Analytical methods including environmental scanning electron microscopy (ESEM),energy dispersive X-ray analysis (EDXA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), inductively coupled plasma (ICP) and atomic absorption spectroscopy (AAS) were used to study CDDC treated wood. The results of this study support modification of CDDC in treated wood with time. Data from ICP and AAS analysis indicated that about 60% of copper and 81% of SDDC are removed from the 1/8"shell of the below ground portion of the stakes after 23 year field exposure. The molar ratio of SDDC to copper for freshly treated southern yellow pine is 2 while it is reduced to 1 after 23 years field exposure. ESEM micrographs and EDXA data confirm the presence of solids rich in copper and sulfur similar to that of CDDC in freshly treated samples. XRD patterns suggest some modifications in the CDDC solids remaining in wood after 23 years.
D P Kamdem, C R McIntyre
Chlorodioxins in pentachlorophenol
1975 - IRG/WP 346 E
At the 6th meeting of the IRG/WP plenary group held on 20 June, 1974, in Vienna, Mr Richardson expressed some concern about dioxins which might be contained as impurities in pentachlorophenol and in sodium pentachlorophenoxide or which might be formed during the combustion of treated wood. He mentioned the malformations that have been noted in Vietnam due to the teratogenic action of the 2, 3, 7, 8 tetrachlorodibenzo-p-dioxin contained in certain preparations of the 2, 4, 5 trichlorophenol used in defoliants. He also raised the question about analogous risks that might come from the presence of octachlorodibenzo-p-dioxin in pentachlorophenol. I specified that work has been carried out on this subject and that the octachlorodibenzo-p-dioxin could in no way be compared to tetra and presented practically no danger considering the doses at which it could be found in pentachlorophenol; consequently no action needed to be taken against it. As stated in point 31 of the minutes of the plenary group meeting, it seemed necessary to me to take stock of the question and to evaluate the possible influence of the presence of chlorodioxins in pentachlorophenol or its sodium salt or even in the combustion products of treated wood. This is the subject of this communication. It is seen that the conclusions are reassuring and they can be summarised in 3 points: (1) Pentachlorophenol does not contain 2, 3, 7, 8 tetrachlorodibenzo-p-dioxin which is by far the most toxic and dangerous chlorodioxin. (2) The chlorodioxins that might be found in pentachlorophenol are the octachlorodibenzo-p-dioxin which has no teratogenic action and is practically non-toxic at the doses at which it is found in pentachlorophenol, and, in much smaller quantities the hexachlorodibenzo-p-dioxin which is 1,000 to 100 times less toxic and less teratogenic than the 2, 3, 7, 8 tetrachlorodibenzo-p-dioxin. (3) The combustion of wood treated with pentachlorophenol or with sodium pentachlorophenoxide does not lead to the- formation of chlorodioxin, but on the contrary, tends to decrease the quantity in relation to that contained in the wood before burning.
About the water and biological resistance of some new chemically modified wood composites
1997 - IRG/WP 97-40077
As well known, wood represents a valuable natural composite material with a very large utilisation as solid wood or in wood based composite materials. Its qualities but also its defects as the dimensional instability, the susceptibility to biological attack, the anisotropy, are due to its complex structure. Research has demonstrated that the chemical modification of wood, meaning the involving of its main chemical components through their reactive alcoholic hydroxyl groups in chemical reactions with different chemical reagents, can be a new way to ameliorate the wood or wood composites but also to obtain new wood based materials. The chemical thermoplasticization of wood, studied theoretically and experimentally by the Japanese researchers as Matsuda, Mori, Morita, Nakano, Shiraishi, Ueda seems to be a very interesting possibility. The paper presents the results of our experiments concerning the chemical thermoplasticization of wood through oligoesterification and the obtaining and characterisation of some products based on this type of chemically modified wood. In fact the main goals of this stage of the researches were: - the obtaining and characterisation of the thermoplastic wood; - the study of the thermoformation possibilities for the thermally flowable material obtained as sawdust; - the evaluation of the possibilities to carry out this chemical modification process as a surface treatment for solid wood; - the evaluation of the water and biological resistance for the obtained products.
M C Timar, M D Mihai, G Baciu
Tebuconazole - Efficiacy, toxicity, physical properties
1995 - IRG/WP 95-30093
An overview ahout the physical properties and toxicology of tebuconazole as well as an update of efficacy data of this triazole are given.
Fipronil - le nouvel insecticide de Rhone Poulenc pour la preservation du bois
1995 - IRG/WP 95-30078
After the 3rd International Symposium in Cannes '95. More trial results and practical information on FIPRONIL, this new insecticide from Rhone Poulenc for Wood Preservation and PCO.
M G E J Van Maanen
Tolylfluanid - fungicide against blue stain in service
1992 - IRG/WP 92-3736
Physical and chemical properties and efficacy of Tolylfluanid are compared with the properties of Dichlofluanid. Whereas the difference in the molecular structure influences the physical properties significantly, the efficacy of both fungicides is comparable. The toxicological and ecotoxicological profile of Tolylfluanid is summarised.