Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Potentials of Liquefied CCB Treated Waste Wood for Wood Preservation  [PDF]
Miha Humar,Franc Budija,David Hrastnik,Bo?tjan Lesar
Drvna Industrija , 2011,
Abstract: Recovered wood is frequently contaminated with biocides and therefore its use is limited. Even more, wood, impregnated with classical chromated copper arsenate (CCA) preservatives is classified as a hazardous waste, therefore solutions for reuse or recovery of this material are sought. One of the options, discussed in this paper is liquefaction and further applications of liquefied wood containing biocide remainings. In order to elucidate this possibilty, spruce and beech wood was impregnated with liquefi ed CCB treated and untreaded spruce wood of various concentrations and exposed to wood decay fungi according to the EN 113 procedure. In paralel, the leaching experiments (ENV 1250-2) were performed as well. The results do not clearly show that liquefied wood is bio-inactive. In most cases the mass loss by fungal attack is decreased compared to the untreated controls. On the other hand, copper leaching from spruce wood, impregnated with the liquefi ed CCB treated wood was significantly reduced. Thus, there are indications that the liquefied wood could be utilized as a binding agent for inorganic biocides.
Optimization of Resinification of Liquefied Products from Trash Antiseptic Wood  [cached]
Fang DING,Hui CHEN,Xiao SUN,Qiuhui ZHANG
Advances in Natural Science , 2011, DOI: 10.3968/j.ans.1715787020110402.l780
Abstract: In this study, Anticorrosive fir was liquefied in phenol, and the liquefied wood were used to produce adhesive by resinification. The effect of resinification time, resinification temperature, molar ratio (NaOH/liquefied wood) and molar ratio (methanal/liquefied wood) on resinification was investigated by orthogonal experiments in term of the viscosity, solid content and pH of resinification product. Adhesive produced by resinification was then used for plywood production, and plywood strength was detected to assess adhesive. According to experiment results, the optimal conditions of resimification are as follow: resinification time of 150 min, resinification temperature of 90°C, molar ratio (NaOH/liquefied wood) of 0.5 and molar ratio (methanal/liquefied wood) of 1.8. Using adhesive produced under the optimal conditions to bond plywood, the bonding strength and formaldehyde emission of plywood produced accorded with related national standard (china), and the plywood produced belonged to calss I. Key words: Antiseptic woods; Resinification; Liquefaction; Phenol; Adhesive
Eficiência do CCB na resistência da madeira de algaroba (Prosopis juliflora (Sw.) D.C.) em ensaio de apodrecimento acelerado
Ramos, Ildefonso Egydio Coutinho;Paes, Juarez Benigno;Farias Sobrinho, Desmoulins Wanderley de;Santos, Gilvan José Campelo dos;
Revista árvore , 2006, DOI: 10.1590/S0100-67622006000500015
Abstract: the objective of research was to analyze the "osmose ccb" preservative efficiency to improve the wood prosopis juliflora (sw) d.c. resistance to postia placenta fungus. in order to meet the objectives proposed, round pieces of p. juliflora were treated by sap displaced method in 1; 2 and 3% of active ingredients of ccb solutions, by 3, 6, 9, 12 and 15 days. wood disks were obtained at three positions (50 cm from the base, middle and top) of the treated pieces. ccb penetration and retention were analyzed at these positions, as well as the resistance to p. placenta fungus (accelerated laboratory test decay) it was found better penetration and retention in pieces submitted to 2% of ccb solutions. the ccb penetration and retention, as well as the resistance of treated wood, in general, decreased from base to top of pieces. the preservative treatment conferred high-level resistance against p. placenta fungus to p. juliflora pieces. this has not occurred only for samples from the top (1% ccb and 15-day treatment; 2% and 9 days; 3% and 3, 12 and 15 days) and from the middle of pieces (3% ccb and 3 and 12-day treatment), which were classified as resistant.
Biodegrading effects of some rot fungi on Pinus caribaea wood
EA Emerhi, BA Ekeke, BA Oyebade
African Journal of Biotechnology , 2008,
Abstract: Wood samples were collected from a ten-year old plantation of Pinus caribaea (morelet) in Ijaiye Forest Reserve, 38 km northwest of Ibadan, Nigeria. The wood samples were inoculated separately with two species of white-rot fungi; Corioliopsis polyzona and Pleurotus squarrosulus, and two species of brownrot fungi; Lentinus lepideus and Gleophyllum, striatum. Wood weight loss due to biodegradation varied from 1.5 – 48.1% for Corioliopsis polyzona, 9.6 – 58.0% for Pleurotus squarrosulus, 40.4 – 78.1% for Lentinus lepideus and 6.8 – 49.2% for Gleophyllum striatum degrading activities. The mode of wood degradation was peculiar with each fungus. Wood decay varied along the tree bole but was not related to height above the ground. The results indicated that biodegradation by rot fungi differs in intensity according to the fungus species and this suggested that preservative impregnation and retention may be the best way to control the rots to make P. caribaea a utility wood.
The most significant fungi: Agents of wood decay in oak forests of Serbia
Milija?evi? Tanja,Karad?i? Dragan
Glasnik ?umarskog Fakulteta , 2007, DOI: 10.2298/gsf0795095m
Abstract: The most widely distributed oak species in Serbia are Q. petrea (sessile oak), Q. cerris (Turkey oak) and Q. frainetto (Hungarian oak) and Quercus robur (common oak), and lignicolous fungi are the major agents of wood decay in natural and coppice oak forests. In this research, 33 species of fungi were identified. Eleven species were described, among which the most significant are: Armillaria mellea, Fomes fomentarius, Hypoxylon deustum Laetiporus sulphureus, Lenzites quercina and Phellinus robustus. This paper presents the morphological characteristics of the most significant identified fungi, their distribution, host plants and significance.
The Influence of Solvent Content in Liquefied Wood and of the Addition of Condensed Tannin on Bonding Quality  [PDF]
Ale? Ugov?ek,Franc Budija,Mirko Kari?,Milan ?ernek
Drvna Industrija , 2011,
Abstract: Liquefied wood (LW) is a promising natural material that can be used as a part of the adhesive formulation. However, adhesive bonds made of LW only, have low durability. The aim of this study was, therefore, to increase the durability of adhesive bonds containing LW. LW was obtained with liquefaction of black poplar wood in ethylene glycol (EG) as the solvent and sulphuric acid (SA) as the catalyst. An optimal time of 120 minutes and a wood/EG mass ratio of 1:3 was defi ned for liquefaction at 180 °C. After liquefaction, the EG was evaporated in order to achieve a low solvent content LW with a fi nal mass ratio of 1:1. A hydroxyl number for 1:3 and 1:1 LW was determined in order to examine the reduction of hydroxyl groups. Four different adhesive mixtures were prepared: LW with a mass ratio of 1:1 (LW1:1 ), LW with a mass ratio of 1:3 (LW1:3 ), LW with a mass ratio of 1:1 and added condensed tannin (CT) (LW1:1 /CT), and LW with a mass ratio of 1:3 and added CT (LW1:3 /CT). The solid beech wood lamellas, which were bonded with these adhesive mixtures, were tested directly after bonding, and later on, after 7, 30 and 50 days. The test results indicated greater bonding shear strength in the case of LW1:1 compared to LW1:3. The addition of CT did not contribute to essentially higher shear strength values. The adhesive mixtures LW1:1 and LW1:1 /CT (uncured and cured) were analyzed using FT-IR spectroscopy. No significant differences were observed between the cured LW1:1 and the LW1:1 /CT samples.
Impact of stereoide fungi on decomposition of oak wood and possibility of its protection  [PDF]
Miri? Milenko
Glasnik ?umarskog Fakulteta , 2005, DOI: 10.2298/gsf0591031m
Abstract: Four stereoide fungi, causers of decay of oak wood, have been investigated as follows: Stereum hirsutum, Chondrostereum purpureum, Stereum rugosum and Xylobolus frustulatus. The field tests have been undertaken in order to determine the influence of the stereoide fungi on the wood of Sessile oak (Quercus petraea) and Austrian oak (Quercus robur). Artificial inoculations with mycelia have been provoked in vital standing trees, as well as in laying trunks. The appearance of dying back symptoms, the rate of mycelia spread through the stem, speed of wound callusing and appearance of fruit bodies or decay symptoms, have been observed. The protection possibility of trunks has been tested as well by using preservatives based on chromo-cupric boron salts, dichlorfluanide and chlorinepyriphos, cupric naphtenates, as well as with antiseptic paste. Microscopically analysis of attacked oak wood has been performed by utilizing of scanning electron (SEM) and standard optical microscope providing normal, fluorescence, polarized and UV light, so that anatomical changes of the wood structure elements influenced by fungal activity have been noted.
Journal of Applied Sciences in Environmental Sanitation , 2012,
Abstract: In the present study 212 specimens of wood decaying fungi were collected from Chhattisgarh, India, during survey in rainy season, 2009- 2010. These were identified, brought in pure culture by tissue culture method on Potato dextrose agar medium. Out of these, 33 species were screened and tested for cellulose degradation capability using filter paper cellulose. The ability of host fungus to utilize insoluble form of cellulose was measured. It was found that, all the 33 wood decaying fungi were able to decompose cellulose at varying degree. Biodegradation of cellulose and CAI were observed maximum with Navisporus floccosus whereas, Pyrofomes tricolor showing minimum biodegradation of cellulose and Flavodon flavus show minimum CAI. It is concluded that cellulose decomposition pattern was vary not only among the genera but also between the species of same genus.
Network Analysis Reveals Ecological Links between N-Fixing Bacteria and Wood-Decaying Fungi  [PDF]
Bj?rn Hoppe, Tiemo Kahl, Peter Karasch, Tesfaye Wubet, Jürgen Bauhus, Fran?ois Buscot, Dirk Krüger
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088141
Abstract: Nitrogen availability in dead wood is highly restricted and associations with N-fixing bacteria are thought to enable wood-decaying fungi to meet their nitrogen requirements for vegetative and generative growth. We assessed the diversity of nifH (dinitrogenase reductase) genes in dead wood of the common temperate tree species Fagus sylvatica and Picea abies from differently managed forest plots in Germany using molecular tools. By incorporating these genes into a large compilation of published nifH sequences and subsequent phylogenetic analyses of deduced proteins we verified the presence of diverse pools corresponding to functional nifH, almost all of which are new to science. The distribution of nifH genes strongly correlated with tree species and decay class, but not with forest management, while higher fungal fructification was correlated with decreasing nitrogen content of the dead wood and positively correlated with nifH diversity, especially during the intermediate stage of wood decay. Network analyses based on non-random species co-occurrence patterns revealed interactions among fungi and N-fixing bacteria in the dead wood and strongly indicate the occurrence of at least commensal relationships between these taxa.
Fourier Transform Infrared Radiation Spectroscopy Applied for Wood Rot Decay and Mould Fungi Growth Detection  [PDF]
Bj?rn Petter Jelle,Per Jostein Hovde
Advances in Materials Science and Engineering , 2012, DOI: 10.1155/2012/969360
Abstract: Material characterization may be carried out by the attenuated total reflectance (ATR) Fourier transform infrared (FTIR) radiation spectroscopical technique, which represents a powerful experimental tool. The ATR technique may be applied on both solid state materials, liquids, and gases with none or only minor sample preparations, also including materials which are nontransparent to IR radiation. This facilitation is made possible by pressing the sample directly onto various crystals, for example, diamond, with high refractive indices, in a special reflectance setup. Thus ATR saves time and enables the study of materials in a pristine condition, that is, the comprehensive sample preparation by pressing thin KBr pellets in traditional FTIR transmittance spectroscopy is hence avoided. Materials and their ageing processes, both ageing by natural and accelerated climate exposure, decomposition and formation of chemical bonds and products, may be studied in an ATR-FTIR analysis. In this work, the ATR-FTIR technique is utilized to detect wood rot decay and mould fungi growth on various building material substrates. An experimental challenge and aim is to be able to detect the wood rot decay and mould fungi growth at early stages when it is barely visible to the naked eye. Another goal is to be able to distinguish between various species of fungi and wood rot. 1. Introduction Wood rot decay and mould fungi growth on building materials represent a challenging problem. In addition to the building damages, for example, wood rot decay, often due to unwanted water ingress, one of the large risks is related to mould fungi growth. Trapped water or moisture, for example, between watertight barriers, which has no possible way to dry or drain out, may lead to mould fungi growth under certain conditions. Unfortunately, these conditions are often fulfilled. The mould fungi initiation and growth are dependent upon the following factors:(i)availability of fungal spores, which are almost always present, except under sterile conditions,(ii)nourishment, for example, wood,(iii)moisture,(iv)temperature,(v)oxygen,(vi)time. Many different species of mould fungi exist, each of them with various requirements to the above initiation and growth factors. For example, a specific fungal specimen may be latent with no growth below a certain temperature and might be exterminated above a certain temperature, where the temperature range will vary for each specimen. The exact relationship between mould fungi growth, with release of airborne fungi, and health problems is not yet fully
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.