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Analysis of tebuconazole in wood treated with Tanalith™ E
1999 - IRG/WP 99-20158
A simple gas chromatographic method for determining tebuconazole in Tanalith™ E treated wood is described. A two step sequential extraction procedure with methanol was used. Sample extracts were analysed without cleanup or concentration using capillary column GC with thermionic specific detection. The performance of the method was assessed using radiata pine (Pinus radiata) sapwood, radiata pine heartwood, and spotted gum (Corymbia citriodora) sapwood as substrates. Recoveries from fortified samples ranged from 97% to 103%. The precision of the method was assessed by analysing a number of actual treated wood samples over a range of retention levels, which produced relative standard deviations in the range of 3% to 8%.
D E Ferlazzo

Effect of asphyxiation on wood decay fungi treated with argon and nitrogen gas
2002 - IRG/WP 02-10452
The effects of low-oxygen conditions, achieved with either argon or nitrogen gas, on the viability of wood decay fungi Coniophora puteana, Antrodia vaillantii and Trametes versicolor, cultivated on PDA medium and infected wood samples, were examined. The fungal cultures were exposed to low oxygen concentration (below 10 ppm) for one to five weeks in hermetically sealed vessels. Anoxic treatment did not affect T. versicolor cultures in the time span of the experiment. Therefore treatment of only C. puteana and A. vaillantii mycelial cultures was extended to 10 and 16 weeks. After treatment, respiration and regeneration of mycelium were tested by measurements of CO2 production and resumed growth of hyphae onto fresh PDA growth medium. The effect of anoxic conditions on the mycelia of treated fungal species was expressed as an increased time needed for regeneration or as a complete absence of growth of inocula taken from the exposed cultures or wooden blocks reintroduced on new nutrient medium. The cultures that were retarded by the low oxygen concentration consequently produced less CO2. For C. puteana cultures, the effects of anoxic treatment became evident in the second week of the treatment. The number of affected cultures rose steadily with the prolongation of anoxic treatment. By the sixteenth week of the anoxic treatment, 80% of the inocula of C. puteana did not regenerate. A. vaillantii inocula regeneration was not affected until after the fourth week of treatment, and similarly for infected wood samples, after five weeks. The influence of anoxic treatment on the cultures of this species was more pronounced on the tenth and especially after the sixteenth week, when 67% of inocula did not regenerate. In general fungal species were differently sensitive to asphyxiation. T. versicolor cultures were not affected by anoxic conditions, caused by either argon or nitrogen gas, and A. vaillantii mycelial cultures proved to be less sensitive than those of C. puteana. In the test with infested wood blocks argon proved to be more effective, compared to nitrogen gas.
C Tavzes, F Pohleven, M Janisek, R J Koestler

Gas chromatographic determination of 1,8-naphthalimide, N-Hydroxy-1,8-naphthalimide (N,N-naphthaloylhydroxylamine) and the sodium salt of N-Hydroxy-1,8-naphthalimide
2003 - IRG/WP 03-20259
A number of naphthalimide (NI) derivatives are used as efficient laser dyes, in medicine or in scanning electron microscopy. Only N,N-naphthaloylhydroxylamine (NHA) has been shown to be an effective wood preservative against wood decay fungi and termite damage. However, limited information is available concerning the analytical detection of NI-derivatives in treated timber. There is a clear need for the analytical characterisation; e.g. with regard to the penetration depth or the assessment of retention after leaching. This paper describes the development of a gas chromatographic method for determination of NI and their derivatives in timber. These investigations were carried out by means of direct thermal desorption-gas chromatography-mass spectrometry (TD-GS-MS) using the pure substances in solution, as well as direct analysis of treated southern yellow pine (SYP). It was shown that the identification of NHA in treated SYP is possible using this analytical technique. Furthermore first evidence is given for determining quantitative data. Surprisingly, the chromatograms and especially mass spectra obtained for NHA and the sodium salt of NHA are identical to the mass spectra of NI. The first results show that TD-GC-MS can be an option in determining the retention levels of NI and their derivatives in wood.
E Melcher, F Green III

Volatile organic compounds (VOC) measured during drying of impregnated timber
2004 - IRG/WP 04-50216
Discussion about drying of impregnated timber has taken place in the Nordic countries under eighties and nineties and goes on nowadays. The drying increase the value of production and the customer gets fewer problems when handles the timber. This introduces a positive attitude to the impregnation as a process and its products. Beside the important information about the advantages of impregnated timber drying, a great help for the integrity of branch and customers will be the acquirement of drying schedules considering the timber quality and emissions of harmful VOC. The objective of the present study was to measure the total content of possible emissions containing organic substances in the vented air during drying of Scots pine timber impregnated for above ground use (preservatives of class AB). A drying charge of 6 m3 consisting of 28120-mm boards was prepared for impregnation. The preservative, a copper-HDO (Wolmanit CX-8, 2 % conc.) was impregnated in the boards according to the full cell process carried out in an industrial autoclave. The impregnated charge was further dried in a laboratory batch kiln to final moisture content of 18.1 %. The duration of drying was 86 h. The content of VOC emitted in the air from the aminoethanol in preservative was measured by gas chromatography technique. Samples from the air were taken directly in and beside the drying kiln. The measurements were carried out in the beginning, middle and at the end of drying. The gas chromatography technique showed to be appropriate for quantitative measuring of the VOC emitted during drying of timber impregnated with Wolmanit CX-8. The emissions measured in the kiln chimney were most intensive in the beginning of drying when the free water was evacuated (31.4 ppm) and decreased exponentially to 7.8 ppm at the end of the process. The study generated some ideas about the organisation of drying schedule for impregnated timber in order to decrease the content of VOC. The results are interpreted regarding the requirements approved by the environmental authorities in Sweden.
N Terziev, V Djokic

Detection of Termite Attack to Wood Stakes in a Monitoring Station Using Ceramic Gas Sensors and Acoustic Emission (AE) Sensor
2003 - IRG/WP 03-20271
To evaluate the termite activity in monitoring stations non-destructively, metabolic gas from termites and acoustic emission generated by feeding of termites were measured. Ten cylindrical stations with small wood stakes of Japanese red pine (Pinus densiflora) were buried around a house attacked by Coptotermes formosanus SHIRAKI. A sample air in the station was collected by sucking through a drilled hole of the station lid and analyzed using two types of ceramic gas sensors (odour- and hydrogen-selective sensors). Acoustic emissions (AEs) were detected by a PZT sensor attached to the cross section of one of the small stakes in the station. The concentrations of two components of the collected gas, odour and hydrogen, and AE event rate per 2 minutes were measured periodically from December 2001 to February 2003. The infestation activity in the station was also evaluated by visual inspection. In the early stage of the experiment, from the first to the third measurements, neither AEs nor significant level of the gas concentration was detected, and no termite was found in any stations. A higher gas concentration of odour and hydrogen and a larger number of AE events were detected since termites have invaded in the stations. These findings suggest that termite attack in the monitoring station can be evaluated by using two types of the gas sensors and AE sensor.
Y Yanase, Y Fujii, S Okumura, T Yoshimura, Y Imamura, T Maekawa, K Suzuki

Preservative treatment of wood-based composites with a mixture formulation of IPBC-silafluofen using supercritical carbon dioxide as a carrier gas
2003 - IRG/WP 03-40251
Wood-based composites treated with a mixture formulation of a fungicide, 3-iodo-2-propynyl butylcarbamate (IPBC) and a termiticide, silafluofen using supercritical carbon dioxide (SC-CO2) as a carrier solvent were tested for their resistance to decay and termite attack in the laboratory. The treatment solution was prepared by mixing both biocides (IPBC 10 + silafluofen 1) with a co-solvent, ethanol to have an identical ratio of each constituent in the commercial formulation for superficial treatment of wood. SC-CO2 treatments were conducted at 35oC/7.85 MPa, 35oC/9.81 MPa and 55oC/11.77 MPa with a direct introduction of the biocidal solution into the treatment vessel where specimens (210 x 30 mm x thickness) of medium density fiberboard, hardwood plywood, softwood plywood, particleboard and oriented strand board were placed. Laboratory tests were conducted with the treated materials according to Japanese standard methods. Results of laboratory tests indicated that the current treatment conditions significantly enhanced the resistance of the treated wood-based composites against fungal and termite attacks. Comparison with the results obtained for wood-based composites treated with an individual biocide showed that treatment with a mixture would not cause any negative effect to the efficacy of each biocide, although the amount of each constituent in a mixture formulation must be carefully decided to provide wood-based composites with a satisfactory performance against any biological degradation when SC-CO2 is used as a carrier solvent.
K Tsunoda, M Muin

Gaseous boron treatments of wood and wood products
1992 - IRG/WP 92-3691
Treatment of wood and wood products by gaseous organoborates has now been under study for about 5 years. This technique has potential for boron treatment of a wide range of substrates from solid wood through to wood composite materials such as particleboard or wet and dry formed fibreboards. The vapour treatment technique is proving to be very flexible in that it can be adapted to integrate into a wide range of process operations and can accommodate special loading requirements. This paper updates the present research in this area and describes treatment of different wood species and wood composite products. We will also anticipate where some of these developments may lead.
A J Bergervoet, R Burton, K Nasheri, D R Page, P Vinden

The potential application of rapid gas-chromatographic assay of microbial respiration to the monitoring of wood decay in field trial situations
1983 - IRG/WP 2196
Gas chromatographic detection of microbial activity (C02 production) within stakes in a field trial situation would appear to provide a sensitive, non-destructive and relatively rapid method for the quantitative assessment of preservative treatments. Most consistent results were obtained when stakes were removed from the soil, washed, saturated with water and incubated in sealed PVC tubes at 25°C for 24 h prior to assay of gas samples from the tubes. Each assay took 1.6 min to perform and stakes were returned to the field within 48 h. Microbial activity was readily detected in untreated Eucalyptus regnans stakes after 18 days field exposure. Stakes pressure impregnated with CCA, busan-30 or creosote displayed consistently low levels of activity to the present time (3 months after insertion).
M A Line

Detection of metabolic gas from termites using ceramic gas sensors
2001 - IRG/WP 01-20222
To evaluate termite attacks in wooden constructions by detecting the metabolic gas from termite colony, the basic performance of three types of ceramic gas sensors (odor-, methane- and hydrogen-selective sensors) was investigated. Four termite groups of different combinations of workers (100 to 1000) and soldiers (10 to 100) of Coptotermes formosanus Shiraki and a small specimen of Japanese red pine and / or wet paper were placed in a container to which the gas sensors were attached. We found that the concentration of gas detected by the hydrogen-selective sensor increased with the number of termites in the container. The performance of this sensor was not influenced by the gases released from the wood specimens. Similar findings were also obtained for the odor-selective sensor, but it detected odor not only from termites, but also from the wood. No significant increase in the gas concentration was noted using the methane-selective sensor, which we speculated may be due to the influence of the humidity changes 63 in the container on the performance of this sensor. The variations in gas concentration associated with the termite activity are also discussed.
Y Yanase, Y Fujii, S Okumura, T Maekawa, K Suzuki, T Yoshimura, Y Imamura

Gaseous preservative treatment of wood
1990 - IRG/WP 3631
A recent development in processing wood with a gaseous preservative means that dry, treated wood can be produced in under 30 hours with the benefits of product diversification, faster stock turnover and the ability to respond to short term demand. About 400,000 m³ of wood are treated each year in New Zealand with boron salts to protect from borer infestation. Traditionally this treatment is effected by dipping the freshly sawn wood into a solution of boron salts and then stacking the wood while the salts diffuse through it. For 50 mm thick timber the diffusion process takes from 5 to 8 weeks. The Forest Research Institute has developed a new technique whereby the treatment is carried out in the gas phase effecting full impregnation within seconds. This process is carried out in a pressure vessel, which acts as both a kiln, preservation vessel and steam conditioning chamber. The wood is first high temperature dried to a low moisture content, exposed to a vapourised organoborate and then steamed. Total time in the vessel is about 30 hours. Preservative treatment in the gas phase is a novel development for the wood processing industry. An outline of the development of the process is presented and the implications for this industry are discussed.
R Burton, A J Bergervoet, K Nasheri, P Vinden, D R Page

Stability of bifenthrin in a commercial phenol-formaldehyde plywood glue
2003 - IRG/WP 03-30311
Liquid phenol formaldehyde (PF) glue mixes used for plywood manufacture are strongly alkaline. At this pH insecticidal additives may not be stable for long periods. In order to establish practical working life of the synthetic pyrethroid insecticide, bifenthrin, in liquid PF glues the concentration of bifenthrin in the glue mix was measured under laboratory conditions over a 24 hour period. Glue batches were prepared in a laboratory mixer set up on an electronic balance with two dose rates of bifenthrin. The glue was stirred continuously, with a cover in place to reduce evaporation. Four replicate portions of glue were removed from the mixer and applied to fluoropolymer-coated rubber discs at fixed periods. The discs were cured immediately in an oven, during which time the film set and became detached from the surface. These discs were extracted with toluene-formic acid (90:10) mixture and the extracts analysed using capillary column GC with electron capture detection. Bifenthrin was found to be exceptionally stable in alkaline PF glue. When the glue was mixed under conditions preventing premature polymerisation, no measurable bifenthrin degradation occurred during the 24 hours.
M J Kennedy, P A Collins, R D Vella

A study of methanogenesis and sulphate-reduction: A possible source of explosive gas mixtures in a gold mine
1989 - IRG/WP 1399
Previous work isolated anaerobic bacteria from timbers and drainage water in a gold mine. The present work identifies the predominant methanogen in the mine ecosystem as Methanobacterium bryantii and sulphate-reducing isolates as Desulphovibrio desulphuricans and Desulphotomaculum antarcticum. Laboratory studies using model systems evaluate the activity of methanogenic and sulphate-reducing bacteria in situ. Most probable numbers (MPN) of bacteria indicate 3.5 x 105 methanogenic and 7.9 x 103 sulphate-reducing bacteria/ml drainage water. MPN values g-1 timber were lower for methanogens but comparable for sulphate-reducers. Laboratory model systems predict methanogenesis as the likely dominant terminal reaction in the mine ecosystem. Maximum calculated rates of methane production were approximately 5 ml methane g-1 wood day-1, however actual rates would never attain this value owing to nutrient limitations and environmental restrictions. Analyses of gas samples extracted from sealed areas verified the presence of methane.
L D Abraham, J F Putterill, A A W Baecker

Effects of Murgul Copper Process flue gases (SO2) on compression strength parallel to the grain of Beech (Fagus orientalis Lipsky.) wood
2008 - IRG/WP 08-40404
In this study was investigated the effect on the compression strength parallel to the grain as mechanical properties of Fagus orientalis Lipsky. wood exposed to SO2 gas and non-exposed. In the experiments the two of four (total) were obtained from Artvin-Ortaköy region and the other two from Artvin-Murgul region. The compression strength parallel to the grain was calculated at the compare of trees are taken from two distinct region. The obtained data of SO2 exposed specimens were compared with non-exposed ones. According to the obtained data of this study suggestions were given. At the end of study no effect of SO2 gas has been determined on the compression strength parallel to the grain of Fagus orientalis Lipsky. wood.
N Ay, E Topaloglu, A Uncu

Effects of Heat-Treatment in Hot Water and Steam Mediums on Gas Permeability of Beech Wood
2011 - IRG/WP 11-40557
Heat-treatment, as a major method of wood modification, improving dimensional stability, and natural durability, has been studied greatly from different aspects. The effect of heat-treatment on gas permeability, as an important physical property of wood, in two different mediums of hot water and steam, as well as in two buffers of 7 and 8, is the main topic of the present study. Hydrothermal treatment made gas permeability decrease to its lowest value among the other treatments (91.6% decrease comparing control treatment). Hydrothermal treatment in buffer 8 made the lowest impact on gas permeability (12.3% decrease). Decrease in gas permeability value was due to settlement of extractives on vessel perforation plates. Gas permeability showed a high significant correlation (0.88) with the amount of swelling in radial direction; it may therefore be concluded that gas permeability may be considered a suitable criterion for predicting the amount of swelling.
H Reza Taghiyari, A Talaei, A Karimi

Effects of Nano-Zycosil on Liquid and Gas Permeability of MDF
2012 - IRG/WP 12-40578
Effects were studied of zycosil nanoparticles, with size range from 30 to 90 nm, on liquid and gas permeability of medium density fiberboard. 100 g of nanozycosil was added to each kg of dry fibers. Density was kept constant at 0.67 g/cm3. The obtained results indicated that addition of zycosil to the mat resulted in a significant increase in gas permeability due to the lower fiber-content in the nanozycosil-treated specimens and the consequent micro-cavities that were formed in the boards. However, the water-repellant property of zycosil nanoparticles compensated for the micro-cavities to some extent, consequently the liquid permeability decreased significantly.
H Reza Taghiyari, K Heidarhaee, P Noori, A Karimi

Surface energy characterization of thermally modified wood using inverse gas chromatography
2013 - IRG/WP 13-20532
The objective of this work is to characterize surface energetics of thermally modified wood. Such information may be useful for a better understanding and predictions of adhesion properties between the modified wood and other material systems, e.g. coatings, adhesives or matrices in composites. Inverse gas chromatography (IGC) was used to study the surface energy characteristics of thermally modified spruce in particle form. Two different wood component samples were prepared, one with a larger and one with a smaller particle size distribution. Measurements of BET specific surface area and dispersive surface energy distribution of the particle samples are presented. Results indicate that a ground wood component of a finer size distribution of thermally modified wood is less energetically heterogeneous compared with a component with a larger size distribution.
S Källbom, K Segerholm, D Jones, M Wålinder

Nano-Zycosil in MDF. Part I: Gas and Liquid Permeability
2014 - IRG/WP 14-40652
Effects were studied of zycosil nanoparticles, with size range from 20 to 80 nm, on liquid and gas permeability of medium density fiberboard. Nanozycosil was used at four consumption levels of 0, 50, 100, and 150 g/kg dry wood fibers. Density of all treatments was kept constant at 0.67 g/cm3. The obtained results indicated that the addition of zycosil to the mat resulted in a significant increase in gas permeability due to the lower fiber-content in the nanozycosil-treated specimens and the consequent micro-cavities that were formed in the boards. However, the water-repellant property of zycosil nanoparticles compensated for the micro-cavities to some extent. High correlation was observed between gas and liquid permeability. The consumption level of 50 g of nanozycosil/kg can be recommended to improve the impermeability property of medium density fiberboard to water.
H Reza Taghiyari, A Karimi, P M D Tahir, O Schmidt, E Bari, P Nouri , A Jahangiri

How carbon stored in harvested wood products contribute in a greenhouse gas accounting perspective
2017 - IRG/WP 17-50327
In 2014 the net annual removal by Norwegian forests was 30.4 mill ton CO2-eqvivalents while the emissions in other sectors was 53.2 mill ton CO2-eqvivalents. Hence, forests can play a major role in the national greenhouse gas balance. But forests also contribute to the carbon pool stored in wood products. The aim of this paper is, by using Norway as an example, to illustrate how the greenhouse gas emission reporting of harvested wood products (HWP) are performed, what results it provides and what the trends are. According to the Norwegian convention reporting to United Nations Framework Convention on Climate Change (UNFCCC) the total Norwegian HWP pool served as a sink (net annual removals) until 2009, thereafter it has served as a source (net annual emissions). Why? The main reason is that since 2006 the number of paper factories in Norway has declined. This has resulted in a drastic reduction of export of paper and paperboards. Additional reasons for the change are periods with reduced use of sawnwood domestically and increased import at the expense of domestic production. The finance crisis in 2008 – 2009 resulted in a temporary marked drop in production value and downscaling of Norwegian production.
G Alfredsen, G Søgaard