Your search resulted in 64 documents. Displaying 25 entries per page.
The lasting dehydration of wood treated by bifluorides worked up in Diffusec noticed by a continual drying of the wood
1999 - IRG/WP 99-30196
After an immersion of sound wood in a solution of Diffusec, in which a combination of acid potassium and ammonium bifluorides = FHF- in dissociated form is present, their potassium and ammonium fluoride ions together with the bifluoride ion = (FHF-) diffuse into the wood. They make use of the woodmoisture available as O-H-O bonds directly attached to the cellulose in the wood fibres to attract the...
H F M Nijman
Environmentally benign wood preservatives based on organic biocide antioxidant combinations: A brief review of laboratory and field exposure results and discussion of a proposed mechanism
2004 - IRG/WP 04-30335
The combination of various organic biocides with commercial antioxidants generally increased the biocides’ efficacy 2-3 fold against wood-destroying fungi in short-term laboratory decay tests, and some positive results have been obtained after 2-4 years of outdoor exposure. The two antioxidants principally examined, propyl gallate and butylated hydroxytoluene, are low cost and, since both are f...
T Schultz, D D Nicholas, W Henry, C Pittman, D Wipf, B Goodell
A diffusion and reaction model for the leaching of Cr-VI from unfixed CCA-treated wood
2001 - IRG/WP 01-50169
A physical model applicable to the leaching of any substance undergoing a first-order fixation reaction with wood is presented. Using this model and a laboratory leaching experiment with small wood samples immersed in water, the radial and tangential diffusion coefficients and the reaction rate constants of Cr-VI in unfixed CCA-treated red pine (Pinus resinosa Ait.) are measured. Reaction rate con...
L Waldron, P A Cooper
Evaluation of tropolone as a wood preservative : activity and mode of action
2002 - IRG/WP 02-30282
The fungicidal activity of 2-hydroxy cyclohepta-2,4,6-trienone (tropolone) analogue of b-thujaplicin a natural product responsible for the durability of heart wood of several
cupressaceous trees was investigated in vitro on growth of white and brown rot fungi. Results obtained show that tropolone, easily prepared from commercially available products,
possesses strong fungicidal activity similar ...
P Gérardin, M Baya, N Delbarre, P N Diouf, D Perrin, P Soulounganga, E Gelhaye,
J P Jacquot, C Rapin
Amine copper reaction with wood components: acidity versus copper adsorption
1997 - IRG/WP 97-30161
The bonding sites for copper in wood from CCA, as well as ammoniacal/amine based systems, has long been a topic of investigation. Both phenolic and carboxylic functional groups have been discussed as potential bonding sites for copper. However, no consensus on the adsorption mechanism has been realized. Thus, the selective adsorption of copper in southern yellow pine from ethanolamine-copper solut...
S M Thomason, E A Pasek
Examination of preservative-treated Pinus sylvestris using electron paramagnetic resonance
1992 - IRG/WP 92-3710
EPR is currently being used to help elucidate the nature and extent of the chemical reactions occurring between wood and copper based timber preservatives. In the work reported here treated Scots pine samples were examined at room temperature and in the frozen state. Plots of the electronic parameters A|| vs. g|| were found to be a useful index of the electronic properties of the various formulati...
A S Hughes, R J Murphy, J F Gibson, A J Cornfield
Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 4: Conversion reactions during storage
1974 - IRG/WP 332
Precipitates simulating those produced in wood by preservative fixation reactions were prepared by the reduction of Boliden K 33 and Celcure AP solutions with hydrogen peroxide and hydrazine. The pH changes on aging at 20 and 50°C were studied and related to the chemistry of fixation previously described. Hydrolysis of copper arsenates may render arsenic acid temporarily water soluble pending pre...
S-E Dahlgren
Comparative study of lignocellulolytic activities of Pleurotus spp. and white rot and brown-rot fungi
1997 - IRG/WP 97-10209
Field and fungal cellar trials have been set up to assess the biocontrol potential of a selected Trichoderma viride isolate in a situation representative of the end use of treated timber in ground contact situations. These trials are designed to give information about the efficacy of biological control as well as the suitability of existing chemical treatment methods for use with biocontrol fungi....
H L Brown, A Bruce
The bacterial transformation of organic biocides; a common mechanism?
2006 - IRG/WP 06-10585
It was found that a number of unformulated organic biocides showed a susceptibility to degradation by proteobacteria. Exposure of tebuconazole, a candidate biocide, chlorothalonil and IPBC to a Ralstonia strain was found to result in biocide detoxification, as demonstrated through HPLC and a bioassay. Exposure of the biocides to a previously identified extracellular factor was also found to resu...
D F Wallace, D J Dickinson
Chemical reactions involved in furfurylation of solid wood - An investigation by ATR-IR spectroscopy
2006 - IRG/WP 06-40347
Wood modification with furfuryl alcohol (FA) has gained renewed interest during the last five to ten years because of advances in process technology and because of increased focus on the environmental hazards of traditional wood impregnation. The reaction mechanisms involved in the furfurylation process are not yet understood in detail. In the work presented here, the chemical reactions and their ...
T Mark Venås, L Garbrecht Thygesen, S Barsberg
Arsenic removal by plant pumping mechanism from arsenic solution using activated aluminum oxide as adsorbent – a preliminary study
2006 - IRG/WP 06-50239
This study evaluated the performance of plant pumping mechanism for removal of arsenic from arsenic solution using activated aluminum oxide as adsorbent. Generally, plants absorb water from soil mainly by osmosis process and toxic elements present in soil also move along with water. To remove toxic elements present in contaminated soils/water, different chemical substances are widely used as
...
B Tarakanadha, H Koyanaka, T Hata, Y Imamura
Wood decay fungi from New Zealand ‘leaky’ buildings: PCR identification and laboratory decay tests of wood preservative-treated Pinus radiata (Part 1)
2007 - IRG/WP 07-10620
Fungi colonising Pinus radiata D. Don framing timber of ‘leaky’ New Zealand buildings were isolated to produce pure cultures. Mycelia from these cultures on agar media were collected to extract DNA. To identify the fungi to the species level, polymerase chain reaction (PCR) with primer pairs ITS1-F and ITS4 were performed followed by sequencing of the internal transcribed spacer (ITS) region. ...
D Stahlhut, R L Farrell, R Wakeling, M Hedley
The characteristics of biodegradation mechanism of gamma-irradiated wood
2007 - IRG/WP 07-20352
Gamma radiation, as an easy, fast and effective sterilisation method, changes molecular structure in pest’s living cells, but also in wooden cell walls. Radiation-induced depolymerisation causes significant changes in wood properties crucial for laboratory testing of wood-preservative effectiveness. Natural durability of wood against rot fungi in lab conditions dependency on different sterilisat...
R Despot, M Hasan, F Pohleven, M Humar, G Rep
Wood decay fungi from New Zealand leaky buildings – PCR identification (Part 2) and aerial spore trapping
2008 - IRG/WP 08-10649
Prior to this study, it was not know which species of decay fungi caused decay in New Zealand leaky buildings. Use of molecular biology methodology, polymerase chain reaction (PCR), and subsequent DNA sequencing, as well as classical mycological techniques based on morphology, has enabled identification of decay fungi and has provided insight into their relative importance based on isolation frequ...
D Stahlhut, R L Farrell, R Wakeling, M Hedley
Bi-oleothermal treatment of wood at atmospheric pressure: resistance to fungi and insects, resistance to weathering and reaction to fire results
2008 - IRG/WP 08-40418
Bi-oleothermal process is a simple treatment which has been developped by CIRAD in cooperation with FCBA. It allows a deep impregnation of wood with hydrophobic products using cheap facilities. The process includes two steps at atmospheric pressure. The first one is a dipping of wood samples in a hot oil bath (between 110 °C and 200°C) which creates an overpressure inside the wood. The second on...
L Podgorski, I Le Bayon, I Paulmier, J-D Lanvin, V Georges, D Grenier, H Baillères, J-M Méot
Antinomic natural self-protection mechanism in long-lasting woods: a case study with three tropical species from French Guiana
2009 - IRG/WP 09-10696
We demonstrate in this work through 3 examples that Amazonian trees may specialize long-lasting woods by means of at least to different approaches. Wallaba impregnates its wood with large amounts of weakly antifungal compounds acting in synergy, while tatajuba and louro vermelho woods are naturally impregnated with antifungal agents. Comparison of biological activities in vitro and concentrations ...
A Rodrigues, M Royer, N Amusant, J Beauchêne, G Herbette, V Eparvier, A Thibaut, L Salmen Espíndola, B Thibaut, D Stien
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
A theoretical-industrial correlation and perspective on copper-based wood preservatives - a review of thermodynamic and kinetic aspects on copper-wood fixation mechanism
2009 - IRG/WP 09-30499
Copper was and it will continue to remain one of the key active component in wood protection industry. Over the past decades, a significant effort from R&D teams in industry, academia and research institutes was directed toward understanding the copper-wood fixation mechanism, optimising the copper retentions in the wood and reduce leaching in order to maximized performance, prolong the lifetime o...
R Craciun, M Maier, J Habicht
Chemical mediated depolymerization of cotton cellulose for the understanding of non-enzymatic fungal decay
2010 - IRG/WP 10-10731
Small, low molecular weight non-enzymatic compounds have been linked to the early stages of brown rot decay as the enzymes involved with holocellulose degradation are found to be too large to penetrate the S3 layer of intact wood cells. The most pronounced of these which were analyzed in this study are hydrogen peroxide, iron, and oxalic. The compounds related to the Fenton reaction: the combinati...
A C Steenkjær Hastrup, B Jensen, F Green III
The Use of Micro-Tensile Testing to Assess Weathering Decay and Oxidative Degradation of Wooden Items
2010 - IRG/WP 10-20433
This paper presents a method to study the weathering performance of wooden items and to assess the oxidative degradation of wood via the Fenton reaction. Weathering resistance and photo-stability of wood was tested using pine wood (Pinus sylvestris) veneer strips measuring approximately 60 µm in thickness. The veneer strips were treated using a reactive chemical to impart surface protection. The ...
C Mai, Yanjun Xie, Zefang Xiao, P D Evans, H Militz
Communities of mold fungi on flooded building materials
2013 - IRG/WP 13-10799
A small building built to residential code was flooded using farmland pond water to a depth of two feet at Tuskegee University. The building was drained and left enclosed for an additional three weeks. A total of 168 material samples were removed either immediately after opening (wet) or seven months after flooding (dry). Wall materials sampled included fiberglass batt insulation, gypsum wallboard...
F Skrobot III, H Aglan, S V Diehl
Characterization of wood modification prepared by in situ polymerization with pre-polymer and the mechanism of modification
2013 - IRG/WP 13-40633
Chemical modification of wood is a potential way to obtain high quality wood. In this study, the fast-growing poplar was impregnated with modifier using a pulse-dipping machine by in situ polymerization. Fungal decay analysis, mechanical properties and dimension stability of the natural and modified woods were investigated. The wood samples were also characterized by X-ray diffraction (XRD) Therma...
Qian Lang, Zeng Bi, Junwen Pu
The Chelator Mediated Fenton System in the Brown Rot Fungi: Details of the Mechanism, and Reasons Why it has Been Ineffective as a Biomimetic Treatment in some Biomass Applications – a Review
2014 - IRG/WP 14-10828
The chelator-mediated Fenton (CMF) reaction requires the action of two types of chelating compounds. The first chelator, oxalate, solubilizes and then sequesters iron, and the second chelator reduces iron. Iron reduction must be controlled near the fungal hyphae to prevent damaging Fenton chemistry from occurring in that location. Similarly, iron reduction must be promoted within the wood/plant ce...
B S Goodell, M Nakamura, J Jellison
Modern Instrumental Methods to Investigate the Mechanism of Biological Decay in Wood Plastic Composites
2014 - IRG/WP 14-40674
Various instrumental techniques were used to study the fungal decay process in wood plastic composite (WPC) boards. Commercial boards exposed near Hilo, Hawaii (HI) for eight years in both sun and shadow locations were inspected and tested periodically. After eight years of exposure, both boards were evaluated using magnetic resonance imaging (MRI), while a selected area of the board exposed in sh...
G Sun, R Ibach, M Gnatowski, J Glaeser, M Leung, J Haight
Durability of reaction to fire performance of FRT wood products in different end use applications – Methods and results
2015 - IRG/WP 15-40705
Fire retardant treatments (FRT) may considerably improve the reaction to fire properties of wood-based products and the highest fire classifications for combustible products can be reached, but the maintained reaction to fire performance e. g. in exterior applications needs to be addressed in order to form a basis for new and reliable wood products with improved fire performance.
A European Techn...
B Östman, L Tsantaridis