Your search resulted in 103 documents. Displaying 25 entries per page.
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
Durability of heat-treated wood
1999 - IRG/WP 99-40145
Heat-treated wood from the French process were laboratory tested against decay using agar block test and a modified soil block test. Water absorption, bending strength, lignin content and acid number were also determined to evaluate the effect of heat treatment. Heat treated samples exhibit a higher lignin content and a lower acid number compared to untreated control indicating the degradation of ...
D P Kamdem, A Pizzi, R Guyonnet, A Jermannaud
Über Hausbock Hylotrupes bajulus (L.), (Col., Cerambycidae), in Laubholz: Versuche mit Laubholzarten, Prüfung der Wirkung von Ligninstoffen und von Ginkgo biloba, Beobachtungen an Hesperophanes. [On House-longhorn Beetle Hylotrupes bajulus (L.), (Col., Cerambycidae) in hardwood: Investigations with several hardwood-species, tests on activity of lignin components and Ginkgo biloba, observations on Hesperophanes]
1982 - IRG/WP 1144
Hylotrupes bajulus-larvae feed and develop in softwoods, hardwood acts as a feeding poison. The reason for this is still little known. According to literature some observations contradict this established opinion and the question was raised, whether the colour-strain scutifer (= lividus) is able to live in hardwood. Testing ten European and tropical hardwood-species (following the DIN-EN test proc...
S Cymorek
Relationship between degradation of wood, cellulose or lignin-related compounds and production of hydroxyl radical or accumulation of oxalic acid in cultures of brown-rot fungi
1994 - IRG/WP 94-10062
The degradation activities of brown rot fungi against wood, cellulose, and lignin-related compounds were measured in cultures containing glucose or wood as a carbon source. Also the activities of one-electron oxidation and hydroxyl radical production and the amount of oxalic acid present in the cultures were measured. The degradation activities of the fungi against wood, crystalline cellulose and ...
S Itakura, T Hirano, H Tanaka, A Enoki
Tunnelling bacteria
1983 - IRG/WP 1186
The micromorphology of decay in wood caused by a certain group of single-cell bacteria, called tunnelling bacteria (TB), is described. TB are characterised by their tunnelling ability within the secondary cell walls of wood fibres. Pure cultures of TB have not yet been obtained although the typical decay patterns can be reproduced using mixed bacterial cultures. Some indications of lignin degradin...
T Nilsson, G F Daniel
Regulation of hyphal sheath formation iron-chelator production by the brown rot fungi Gloeophyllum trabeum and Postia placenta
1994 - IRG/WP 94-10074
Hyphal sheath formation and iron-chelator production by liquid cultures of the brown rot fungi Gloeophyllum trabeum and Postia placenta were monitored over time. The effects of incubation at various temperatures, pH's and concentrations of iron, manganese and nitrogen were determined. Hyphal sheath production was observed microscopically and quantified with JAVA video analysis. The hyphal...
Y Chen, J Jellison
The influence of drying and chemical stress on the lignin degradation in aspen by Phanerochaete chrysosporium
1992 - IRG/WP 92-1573
Wood wafers of Populus tremuloides sapwood were incubated on common media with the white rot fungus Phanaerochaete chrysosporium (wild isolate) and subjected to cyclic drying or chemical agents (low levels of borate or trifluoperazine [a calmodulin antagonist]). After a mass loss of approximately 5.5%, wafers were dried and analyzed for acid-insoluble lignin. Those wafers containing chemical agent...
E L Schmidt, Y-L Lin
Dimensional stabilization and decay resistance of wood treated with brown-rotted lignin and copper sulfate
1990 - IRG/WP 3608
The objective of this study was to evaluate the potential usefulness of brown-rotted lignin (BRL) as a dimensional stabilization and copper complexing agent for wood treatment. For dimensional stabilization, aqueous solutions of the lignin extract were combined with either copper sulfate, glyoxal or other additives. Anti-shrink efficiency (ASE) values as high as 42% were obtained with wood treated...
L Jin, D D Nicholas, T Schultz
Mechanistic aspects of the reactions of copper complexes with lignin in the presence of hydrogen peroxide and lipid hydroperoxide model compounds as proposed for white rot fungi
2001 - IRG/WP 01-10399
The structural principles and the oxidative reactions of the catalytic system consisting of copper, hydroperoxides, and copper coordination compounds that contain aromatic nitrogen atoms are similar to those of catalytic centers of oxidative enzymes involved in delignification reactions of white rot fungi. The system is capable of selectively degrading lignin and its low molecular weight would all...
K Fackler, P Lamaipis, E Srebotnik, M Humar, C Tavzes, F Pohleven, M Sentjurc, T Watanabe, K Messner
Influence of variable lignin content amongst hardwoods on soft-rot susceptibility and performance of CCA preservative
1982 - IRG/WP 1151
This paper presents the outline of an argument, based on both new and established data, which relates varying lignin content to variation of soft-rot susceptibility between hardwood species and of performance of CCA preservatives in controlling soft-rot. Although more data need to be generated to prove this relationship, sufficient evidence exists for the hypothesis to be given close attention, pa...
J A Butcher, T Nilsson
Weathering of copper-amine treated wood
2000 - IRG/WP 00-40155
Copper ethanolamine (Cu-EA) treated southern pine (SP) were artificially weathered with a QUV Weathering Tester. The weathering regime was composed of a continuous UV-light irradiation for 2 hours followed by a water spray for 18 minutes for a total time of 1200 hours. The changes on the surface of the weathered samples were characterized by Fourier transform infrared spectroscopy (FTIR) analysis,...
J Zhang, D P Kamdem
EPR observation of Mn(II) in decayed wood
2002 - IRG/WP 02-10443
Preliminary Electron Paramagnetic Resonance (EPR) studies of copper/chromium (CC) treated spruce wood, subjected to laboratory soil decay test showed increased intensities of Mn(II) EPR signal in partially decayed specimens. Several reasons might be responsible for this phenomenon: Mn(II) could originate from the wood after being released from the typical ligand binding, from reduction of other Mn...
M Petric, M Humar, P Kalan, F Pohleven, U Schoknecht, M Šentjurc
Genetic Engineering in tree breeding
1998 - IRG/WP 98-10294
The genetic improvement of forest trees by classical breeding is a slow process in comparison with that of annual crops. Tree breeding however is of great importance and has led to trees with better growth characteristics and better disease resistance. An important wood characteristic which has been neglected in breeding programs is wood durability. The durability of the wood will determine for wh...
J Van Doorsselaere, H Beeckman, M Van Montagu, W Boerjan
Comments on soft rot attack in timbers treated with CCA preservatives: A document for discussion
1982 - IRG/WP 1167
This paper is not based on any particular results but rather on several observations of soft-rot during many years of studies, and on a review of the existing literature. The short time available has unfortunately not permitted a detailed review of the literature. Data and knowledge of important facts are lacking for several aspects of soft-rot attack and for reactions occurring in the wood as a r...
T Nilsson
Surface characteristics of wood treated with various AAC, ACQ and CCA formulations after weathering
1991 - IRG/WP 2369
Wood samples treated with various alkylammonium compounds (AACs) as well as ammoniacal copper quat (ACQ) and chromated copper arsenate (CCA) have been studied in accelerated weathering experiments. Microscopic examination of the surfaces of these samples after exposure in a weatherometer revealed several different changes. Samples treated with didecyldimethyl ammonium chloride (DDAC) show consider...
L Jin, K J Archer, A F Preston
Micromorphology of oak wood degraded by brown rot fungus Coniophora puteana
2000 - IRG/WP 00-10356
To characterize the degradation of hardwood by brown rot fungus, Coniophora puteana was incubated on the wood blocks of Quercus accutissima. For comparison, the same fungus was also incubated on the pine wood blocks of Pinus densiflora. In softwood, the shape of the wood cells and thickness of the cell appeared unchanged even the loss of birefringence in the affected areas. In contrast, oak wood d...
Yoon Soo Kim, Seung-Gon Wi, Kwang-Ho Lee
FTIR characterization of copper ethanolamine - wood interaction
1999 - IRG/WP 99-20154
The interaction of copper ethanolamine (Cu-EA) and wood components was studied by using Fourier transform infrared spectroscopy (FTIR). In Cu-EA treated wood, significant reduction was noticed on the band attributed to carbonyl vibration from carboxylic groups at 1735±5 cm-1 and an increase in band intensity was obtained from carbonyl in carboxylate at 1595±5 cm-1. The same observation was made ...
Jun Zhang, D P Kamdem
The examination of preservative-treated radiata pine using electron spin resonance spectroscopy
1987 - IRG/WP 3423
Electron spin resonance spectroscopy (ESR) may be used to characterise the molecular environment of chemical species containing unpaired electrons. These species include free radicals, bi-radicals, point defects in solids, localised crystal imperfections and many transition metal ions. ESR has previously been applied to the examination of wood weathering or wood pyrolysis and now FRI and Massey Un...
D V Plackett, E W Ainscough, A M Brodie
Micromorphological and chemical changes of archaeological woods from wrecked ship's timbers
1987 - IRG/WP 4136
Micromorphological and chemical alterations of sea-waterlogged woods obtained from the ship-wrecked materials which had been submerged in Yellow Sea for over 700 years were investigated. The woods were deteriorated in varying degrees by marine organisms depending on species and parts of the woods. Under the light and scanning electron microscope the morphological characteristics of deteriorated wo...
Y S Kim
FTIR studies on the weathering of didecyldimethylammonium compound (DDAC) treated wood
1993 - IRG/WP 93-30013
Wood treated with alkylammonium compounds (AACs), such as DDAC, weathered more rapidly than untreated wood. In order to examine the influence of DDAC treatment of wood on its weathering, treated and untreated microtomed sections of southern yellow pine earlywood of various thicknesses, were prepared and weathered for approximately one month. The changes in these samples were monitored using FTIR. ...
R Liu, J N R Ruddick
Defining fungal decay types - A proposal for discussion
1985 - IRG/WP 1264
The present definitions of the fungal decay types, white rot, brown rot, and soft rot are somewhat vague. The definitions are based on a mixture of criteria involving morphological and chemical aspects of decay as well as taxonomic affiliation of the responsible fungal species. The present vague definitions have led some fungi being erroneously places in a wrong decay type. Furthermore, some fungi...
T Nilsson
A substantively bonded water repellent treatment based on chromium carboxylates
1985 - IRG/WP 3344
Chromium carboxylates soluble in toluene have been synthesised and applied to Scots pine (Pinus sylvestris) sapwood. Without any further treatment, the compounds may be readily leached from wood surfaces with toluene. After a period of heating however, they become fixed to the cell wall, substantial amounts being resistant to leaching even under reflux conditions for several hours. Treatment of wo...
J K Wright, W B Banks, W J Eilbeck
Experimental variations in the distribution of CCA preservative in lignin and holocellulose as a function of treating conditions (temperature, concentration, pH, species, and time)
1984 - IRG/WP 3277
The exact distributions between lignin and holocellulose and retentions on wood of copper, chromium and arsenic as a function of various sets of conditions in a 3x3x4x2 factorial experiment in which combinations of three temperatures of treatment, three CCA solution concentrations, four pH's of the initial CCA solution and two timber species, namely Pinus radiata and Eucalyptus grandis, a...
A Pizzi, E Orovan, M Singmin, A Jansen, M C Vogel
Extracellular laccase production in brown-rot fungus Coniophora puteana
2001 - IRG/WP 01-10391
Coniophora puteana, one of representing brown-rot fungus, was investigated in terms of extracellular ligninolytic enzyme production. Three fungal strains of C. puteana were inoculated in liquid culture medium with sawdust of pine and oak wood. Extracellular laccase production was observed in some strains of C. puteana in the culture medium with sawdust of oak wood. The highest activity occurred at...
Kwang-Ho Lee, Seung-Gon Wi, Yoon Soo Kim
Influence of ethanolamine on lignin depolymerization and copper leaching from treated Norway spruce and beech wood
2007 - IRG/WP 07-30423
Copper-ethanolamine based wood preservatives are replacing several classical copper-chromium based solutions, due to foreseen ban of chromium. Fixation of copper-ethanolamine based wood preservatives is not as good as fixation of copper-chromium ones. The main object of this manuscript was to prove, that ethanolamine is the prime reason for insufficient fixation of copper-ethanolamine formulations...
M Humar, B Bucar, M Zupancic, D Žlindra, F Pohleven