Your search resulted in 48 documents. Displaying 25 entries per page.
Detection of feeding behaviour of termites using AE monitoring
1991 - IRG/WP 1514
Using acoustic emission (AE) monitoring, the feeding activity of the termite inhabiting a wood specimen was investigated. The amplitude and the rate of AE from the specimen of Coptotermes formosanus Shiraki was larger than that of Reticulitermes speratus Kolbe. The AE event rate was higher in the specimen with soldiers than without soldiers. The AE event rate decreased according to the resistance of wood specimens against termite attack.
Y Imamura, M Tokoro, M Owada, Y Fujii, M Noguchi
Feasibility of termite control using crushed cement-stabilized sludge (Polynite) as a physical barrier and acoustic emission (AE) monitoring
2000 - IRG/WP 00-10381
In Japan, the damages by the subterranean termites (Coptotermes formosanus Shiraki and Reticulitermes speratus Kolbe) are more common. Recently, the more attention is paid to the methods of the termite controls of less- or non-chemical. As one of the non- chemical treatment, physical barrier using particles as basalts 1) , granites, and gravels 2) were investigated in terms of its safety, cost effectiveness and duration of performance, and there were also examples that the physical barriers using some particles have been put to practical use in a few countries except in Japan. Ebeling and Pence showed that the relationship between particle size and termite body size is an important factor in controlling tunneling activity of subterranean termites, and the crushed volcanic cinders of 0.85-2.36 mm in diameter prevented R. hesperus from penetrating 3) . Tamashiro and co- workers indicated that the particles of particular sizes (1.70-2.40 mm in diameter) prevented C. formosanus from penetrating 4) . Su and co- workers investigated the penetration of the sand barrier consisting of crushed quartz rocks and fossilized coral by C. formosanus in laboratory- and field-testing 5, 6) . These results show that it is important to investigate the relationships between the size of termites and particles to evaluate the effects of the physical barrier using particles. On the other hand, in Japan surplus soils and sludge of sixty million tons per annum are discharged from construction sites. The recycle techniques using the surplus soils and sludge and the development of the market for these recycled products are the theme of importance. The crushed cement- stabilized sludge (Polynite) as one of the recycled products of surplus soils and sludge is one of the newly developed and recycled material. It is technically suitable for mass production, has grate cost effectiveness, and is easy to uniform the particle size. In this study, the feasibility of a physical barrier using Polynite uniformed the particle size for termite was examined in a laboratory testing. AE monitoring 7-13) as a method forthe detection of the penetration of termites into the Polynite barrier at an early stage was also investigated, for the application of Polynite barrier in the house.
Y Yanase, M Shibata, Y Fujii, S Okumura, K Iwamoto, T Nogiwa, T Yoshimura, Y Imamura
Feasibility of AE (Acoustic Emission) monitoring for the detection of the activities of wood-destroying insects
1992 - IRG/WP 92-2416
The feasibility of acoustic emission (AE) as a nondestructive testing method for the detection of the wood destroying insects was investigated. AEs were detected from the wood specimens under feeding attack of sugi bark borers or powder-post beetles. However, the feasible monitoring area of an AE sensor is influenced by the attenuation of AE amplitude, so that this could be a problem in the practical AE measurements, especially with wood specimens of higher moisture content.
Y Fujii, Y Imamura, E Shibata, M Noguchi
Detection of Acoustic Emission (AE) generated by termite attack in a wooden house
1999 - IRG/WP 99-20166
Recently, considerable attention has been paid to methods for termite control, which involves few or no chemicals. To reduce the amount of termiticide needed, it is necessary to detect termite attack in wood as early as possible. The feasibility of acoustic emission (AE) monitoring for the nondestructive detection of termite attack has been discussed previously. In this study, we propose some technical solution for the application of AE monitoring to practical control operations. Using a needle-type waveguide combined with an AE sensor (PZT sensor), AEs generated and propagated within floors and walls could be detected effectively. A 0.04 mm-thick sample of the piezoelectric polymer PVDF, which was inserted between the construction members of wooden houses, could detect Aes propagated both in such members and at joint surfaces, although PVDF film is less sensitive than a PZT sensor. The feasibility of using a portable AE detector as the input device for a total security system against termite attack in a house is also discussed.
Y Fujii, Y Yanase, T Yoshimura, Y Imamura, S Okumura, M Kozaki
Detection of termite attack in wood using AE monitoring
1990 - IRG/WP 2355
An acoustic emission (AE) monitoring method for detecting termite activity in wood was applied to lumber of 3 by 3 cm to 10 by 10 cm square, 1 m long. Furthermore, the propagation of AEs due to the feeding activities of termites in the specimens and the locations of AE sources were analyzed. Also discussed was the feasibility of the method applied to posts out in the field of subterranean termites. The results obtained from laboratory and field tests suggest that AE monitoring could be an effective non-destructive method to detect feeding activity of termites even in the incipient stages of the termite attack in wood.
Y Fujii, M Owada, M Noguchi, Y Imamura, M Tokoro
A Long-term Observation of Termite Activity in The Nest by Continuous Acoustic Emission (AE) Monitoring
2003 - IRG/WP 03-20280
In order to evaluate the influence of temperature on the termite activity, acoustic emission (AE) monitoring was applied to two nests of Coptotermes formosanus SHIRAKI; a nest in the stem of a standing tree and a nest in the underground of a wooden house, respectively. Temperature change in and around the nests were continuously measured for about one year using thermocouples at four points; the centre of the nest, the periphery of the nest, the environment around the nest, and the underground, respectively. AEs were detected at the centre of nest and underneath the nest sphere by using wave-guides inserted into the nest of the standing tree and at the centre of nest. AEs were also detected at the wooden construction member near the nest in the wooden house. The termites in the nests were periodically stimulated by rotating, drawing and sticking the wave-guides. The temperatures in the both nests varied from 5 to 35 °C during the experiment. The highest and the lowest temperatures were recorded in August and February, respectively. The highest AEs event rate was recorded when the temperature of the nest in the tree was between 30 and 35 °C and when the temperature of the nest under the house was above 25 °C. In winter, when the nest temperature was below 10 °C, no significant numbers of AE were detected. These findings clearly show that AE generation has a close relation to the termite activities, which are influenced by the temperature in the nest.
Y Yanase, Y Fujii, S Okumura, T Yoshimura, Y Imamura
Using AE monitoring for detecting economically important species of termites in California
1991 - IRG/WP 2375
Acoustic emission (AE) monitoring was conducted on wooden samples containing three economically important species of termites in California (dampwood termite, Zootermopsis nevadensis, Western drywood termite, Incisitermes minor, and Western subterranean termite, Reticulitermes hesperus). Laboratory AE studies included varying termite species, as well as 7 day studies exploring the periodicity of termite behavior. The results from the laboratory tests revealed significant differences in AE events between species, days, and sensors used. In a second study, the distance that AE signals could be detected in 2.6 m (8 ft.) long, 52 x 102 mm² (2 by 4 in.) wooden studs was also explored for the dampwood termite. Acoustic emission signals were detectable for up to 2.2 m in wood for dampwood termites. This study is compared with other investigations exploring the feasibility of using AE to detect termites.
V R Lewis, R L Lemaster, F C Beall, D L Wood
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
Control of termite attack using a trapping method and acoustic emission (AE) monitoring a case study at an electric power plant
1997 - IRG/WP 97-10224
To prevent subterranean termites (Coptotermes formosanus Shiraki and Reticulitermes speratus Kolbe) from invading the buildings of an electric power plant and to control their attack, artificial traps were buried around the buildings. The attack of the termites in and around the traps was monitored by detecting acoustic emissions (AE) generated by the feeding behavior of the workers. The cylindrical artificial traps were 600 mm long and 300 mm in diameter, and consisted of pieces of Japanese red pine surrounded by slender polystyrene foam sticks. Termite inhabitation was observed in eight of the ten traps set, and particularly high levels were found in three traps. The traps were renewed every one or two months. The amount of termites inhabiting the traps decreased drastically after the first renewal, but varied only slightly over the following two and a half years. The amount of termites in the traps increased when the traps were not renewed. Termite activity was significantly restricted by installing artificial traps and no additional serious attacks were found in or around the buildings during the study period. AEs generated by feeding activities were monitored by piezoelectric AE sensors attached to the wooden sticks in the traps or to wooden bait stakes near the trap. The rate of AE events varied according to feeding activity which was associated with the number of termites in the trap and the temperature.
Y Fujii, Y Imamura, E Iwatsubo, S Yamamoto
Make ready of a detection system for insect attack by acoustical method
1996 - IRG/WP 96-10183
A contract CRAFT of European research allowed to build a detector prototype able to diagnose on site the presence of Hylotrupes bajulus and termites, even during the first stages of infestation when no sign of activity is visible. Based on non destructive control technics, the device picks up the acoustical waves emitted by the insects in the wood fibers. The amplification and the filtering of the signal delivered by the piezo-electric sensors is made by an electronic module. The signal is numerized and transfered to a calculation processor. The diagnosis and automatic insect identification require a computer treatment by neuro-fuzzy processing. With the help of neural networks, it memorizes the sign of insects identified by an expert. This knowledge, translated in fuzzy logic is exploited to analyze in true time all sign coming in and automatically diagnose the level of infestation.
M Hyvernaud, F Wiest, M-M Serment, M Angulo, O Winkel
Detection of termite attack in wood using acoustic emission
1989 - IRG/WP 2331
Acoustic emission (AE) is the elastic wave produced by the strain energy released in the process of fracture of a material and propagates through it. The object of this report is to detect AEs produced by the termite activities and to evaluate the possibility of using an AE monitoring test to nondestructively detect the termite attack in wood. It was revealed that AEs were detected from the specimens under termite-attack and the rate of AE events increased according to the number of the inhabiting termites. As no AE was detected from the specimens with soldiers only, it was assumed that workers should generate AEs through feeding activities. It was also revealed that the distribution of AE sources corresponded to that of the region attacked by termites in the specimen.
Y Fujii, M Noguchi, Y Imamura, M Tokoro
Use of Acoustic Emission (AE) to detect activity of common European dry-woodboring insects: some practical considerations
2013 - IRG/WP 13-10803
Old house borer (Hylotrupes bajulus), Furniture beetle (Anobium punctatum), and Deathwatch beetle (Xestobium rufovillosum) are common dry-woodboring insects occurring throughout Europe. With the aim to prevent unnecessary use of biocidal products, to protect valuable wooden elements and objects from unwanted influences, and to have a more objective method, SHR has started to study the use of acoustic emission (AE) to assess activity of attack by these insects. This manuscript deals with the results of some experiments done in order to collect knowledge about the influence of (low) temperature or possible daily rhythms on the activity of the insects. Such knowledge is crucial for a trustworthy application of AE detection for European dry-woodboring insects in practice. Based on an 8-day-test with Hylotrupes with normal daily variation in temperature it is concluded that under these circumstances, temperature is the main influencing factor regarding insect activity. For individual larvae, phases of inactivity exist with a duration of up to 30 minutes. In practice, where probably more than one larva is present at one specific time, in the absence of AE events, measuring periods may need to be extended to at least these 30 minutes. With regard to minimum temperatures for detection, the insect species studied show small differences in behaviour at low temperature. Because the number of registered hits for all species shows a marked decrease at temperatures becoming lower than 10 °C, it is recommended that decisive assessments using AE for detection of activity of these dry-woodboring insects should be done at (wood) temperatures of 10 °C or higher.
J G M Creemers
Nondestructive Detection of Biodeterioration in Indonesian Traditional Wooden Construction of “Joglo”
2014 - IRG/WP 14-10834
To decide the repairing and reinforcement method for wooden constructions, it is necessary to get the enough and precise information on the status of the construction beforehand, especially the distribution and the degree of the biodeterioration, such as decay or insect attack (e.g. termite attack). In this study, damage of biodeterioration to teak wood used in Indonesian traditional wooden construction of “Joglo” was investigated by evaluating ultrasonic velocity, moisture content, acoustic emission, and so on. Damages by dry-wood termite or fungi were found in joglo constructions in sultans’ palaces and in the area of Kotagete. The relationship of damages by dry-wood termite or fungi to ultrasonic velocity in the teak wood and to moisture content was discussed. The monitoring of acoustic emission generated by dry-wood termite attack was also carried out for the detection of termite attack in the wooden structure.
Y Yanase, T Mori, T Yoshimura, Y P Prihatmaji, J Sulistyo, S Doi
Remote sensing for detection of termite infestations—Proof of Concept
2015 - IRG/WP 15-10846
This paper reports the results of a search to discover the most cost effective and robust method of detecting Reticulitermes flavipes infestations in structural members of remote bridges, homes and other wooden structures and transmitting these results to internet cloud storage thus obviating routine travel to these structures for periodic visual inspections. Duplicate stainless steel tanks were constructed for housing R. flavipes colonies and commodity size dimension lumber members. Overall, results indicated that the simplest and cheapest independent variables to measure and send were: temperature (ºC), relative humidity (% RH); dew point (DPºC) and wood moisture content (WPE %) using off-the-shelf commercially available sensor systems. Above ground termite bait stations were determined to be the best method of housing the various sensors to permit ease of subsequent baiting if any termite activity was detected. We conclude that it is feasible and cost effective to monitor valuable wooden structures, like historic covered bridges, against termite infestation and potential structural damage.
F Green III, R A Arango, C R Boardman, K J Bourne, J C Hermanson, R A Munson
Nondestructive analysis of oviposition of the bamboo powderpost beetle Dinoderus minutus using acoustic emission and X-ray CT
2017 - IRG/WP 17-10889
The bamboo powderpost beetle Dinoderus minutus is a major pest of dry bamboo culms in Japan. In this study, acoustic emission (AE) and X-ray computed tomography (CT) was applied to the nondestructive analysis of the ovipositional behavior of adult D. minutus beetles inside bamboo pieces. Newly mated adult females were individually exposed to oviposition bamboo pieces prepared from culms of Phyllostachys bambusoides. AE measurement of the bamboo pieces were conducted continuously using AE sensors with a resonant frequency of 150 kHz. The bamboo pieces were scanned by the microfocus X-ray CT system with intervals of 2–5 d to observe the oviposition tunnels and eggs inside. Time courses of hourly AE hit rate showed that the female adults immediately started tunneling, and the tunneling activity continued almost ceaselessly. Oviposition tunnels bored across vascular bundles of bamboo and eggs deposited in the vessels were captured in X-ray CT images, and the length of oviposition tunnels and the number of eggs were measured.
H Watanabe, Y Yanase, Y Fujii
Comparison of AE-apparatus for detection of activity of Old house borer larvae, including reality check
2021 - IRG/WP 21-10981
As part of the German funded project ‘InsectDetect’ comparative measurements were done with three different Acoustic-Emission-(AE)-apparatus on 14 pine beams in order to assess presence of active attack by the Old house borer (Hylotrupes bajulus (L.)). In all beams active attack was measured, though in varying intensity. This was corroborated by completely dissecting 10 of the beams. All three AE-systems proved suitable to find active attack, although their results in terms of numbers of events are different even when used in the same situation. Therefore, it is important that the operator is familiar with the technical functioning of the system that is used in order to be able to interpret the results reliably. The dissection of the beams showed that there is also an element of chance in these measurements regarding proximity of sensors to gnawing larvae and temporal larval inactivity. Still, such measurements with these apparatuses can give an answer to the question whether active attack of wood-boring insects is present.
J Creemers, B Plinke, U Noldt
Modélisation sur maquette du rejet accidentel d'un gaz toxique et inflammable dans l'atmosphere - Emission de type "bouffée d'oxyde d'éthyléne [Water model simulation of toxic and flammable gases in the environment on industrial sites - Puff of ethylen oxide]
1990 - IRG/WP 3576
Acoustic communication between Microcerotermes crassus Snyder
1982 - IRG/WP 1158
An unusual acoustic communication within a nest of Microcerotermes crassus SNYDER is reported. The signals produced by the termites are described and possible reasons for this behavior are considered.
Rates of emission from CCA-treated wood in the marine environment: measurement, modelling and requirements for further research
2001 - IRG/WP 01-50166-12
Accurate estimates of rates of emission of leachate from preservative treated wood are crucial for realistic predictions of the environmental impact of its use in maritime construction. Estimates are available for some commonly used preservatives, but these vary widely. Though variable, these measurements suggest that emission generally decreases exponentially with time. Part of the variation is due to differences in methodology employed. Physical and chemical characteristics of the seawater used (e.g. temperature, salinity, pH and oxygen content) affect emission rate. So too do the specifics of the treatment process especially the preservative formulation used, and pre- and post-treatment handling of the wood. The nature of the treated wood samples is also important, with misleadingly high estimates being obtained from samples with unrepresentatively high proportions of cross-cut surfaces. A suggested strategy for developing an informative and standardised methodology is discussed. To form useful models of impacts of leaching, emission rates need to be considered in conjunction with site-specific information regarding a) water exchange rates between the area where leaching occurs and the sea, and b) the extent of partitioning of leachate between the water column, biota and sediment. The risk of environmental impact may be reduced by modification to treatment procedures and by careful planning of installation.
S M Cragg, C J Brown, R A Albuquerque, R A Eaton
Methane emission by termites, Coptotermes formosanus Shiraki
1995 - IRG/WP 95-10099
Association of methanogenic bacteria only with the smallest-sized symbiotic protozoa Spirotrichonympha leidyi Koidzumi was evidenced by epifluorescence microscopic observations. Workers, which were collected from a laboratory colony and placed in a test container with water supply emitted methane at a relatively constant rate with a peak of 0.76 nmol/termite/hr within the first 72 hrs after the initiation of measurement. Soldiers, as expected, produced less methane with a maximum rate of 0.019 nmol/termite/hr. Although methane formation is considered important to termites in order to keep physiological balance, that undesirably contributes to global warming.
K Tsunoda, W Ohmura, M Tokoro, T Yoshimura
A review of environmental emissions from building and construction materials in comparison with preserved wood
2005 - IRG/WP 05-50224-11
A review of the public domain literature concerning emissions to the environment from materials which are used in the construction of buildings (e.g. Concrete, Asphalt, Galvanised Steel), in comparison with preserved wood, and a review of the approaches taken by the construction sector in assessing the risk from environmental emissions, in comparison with the approaches taken by the wood preservation sector.
E F Baines
Measurement of VOC emissions from curative treated wood: A new emission test chamber
2001 - IRG/WP 01-50166-13
A poor indoor air quality (IAQ) is now recognized as a potential factor affecting occupants health. There are three basic strategies to improve IAQ: source control, improvement of the ventilation and use of air cleaners. Usually, the most efficient way to improve IAQ is to eliminate the different pollutant sources or to reduce their emissions. In order to precisely measure emissions from building products and estimate the potential heath impact of emitted pollutants, standardised analytical methods are needed. The aim of this paper is to present the new standards prepared by the European Committee for Standardization (CEN) and the International Organization for Standardization (ISO) for the measurement of indoor air pollutants and their application to the characterization of emissions from wood products. The prestandard ENV 13419, subdivided in three parts, has been prepared by the CEN technical committee 264 : ??ENV 13419-1 : Building products - Determination of the emission of volatile organic compounds - Part 1 : Emission test chamber method, ??ENV 13419-2 : Building products - Determination of the emission of volatile organic compounds - Part 2 : Emission test cell method, ??ENV 13419-3 : Building products - Determination of the emission of volatile organic compounds - Part 3 : Procedure for sampling, storage of samples and preparation of test specimens. The two first parts of the prestandard ENV 13419 specify a general laboratory test method for the determination of the area specific emission rate of volatile organic compounds (VOCs) from newly produced building products under defined climate conditions in a test chamber (Part 1) or cell (Part 2). The third part specifies for solid, liquid or combined products, the sampling procedure, transport and storage conditions and preparation of test specimens. In France, those European prestandards have been translated by the French Normalisation Association (AFNOR) in three experimental standards : XP ENV 13419-1, XP ENV 13419-2 and XP ENV 13419-3 [1-3]. In parallel to the ongoing work at CEN, the technical committee 146 of International Organization for Standardization (ISO) has prepared the draft international standard ISO/DIS 16000 related to indoor air. Part 6 of this standard specifies a method for the determination of the emission of single volatile organic compounds (VOCs) and total volatile organic compounds (TVOC) from building materials using test chambers and cells : ??ISO/DIS 16000-6 : Indoor air - Part 6 : Determination of volatile organic compounds in indoor and chamber air by active sampling on TENAX TA sorbent, thermal desorption and gas chromatography using MS/FID. It is intended that, after the final voting stage, the CEN prestandards (Parts 1-3) will be taken over by ISO and that Part 6 of the ISO standard will be taken over by CEN as the fourth part of the ENV 13419 prestandard. As an example, the volatile organic compounds emissions from preservative treated wood samples were characterised according to the CEN ENV 13419-1 prestandard describing the emission test chamber method and to the ISO/DIS 16000-6 prestandard for the analytical method. Two representative wood preservatives (hydrodispersable and petroleum solvent formulation) were tested for this purpose. The VOCs concentrations in the test chamber were monitored during 6 days following a simulated curative wood treatment.
F Maupetit, O Ramalho, C Yrieix
How to determine what is a realistic emission from treated wood - basic reflections
1998 - IRG/WP 98-50105
Emissions from treated wood occur by evaporation and by leaching. Up to date by far more experience exists on leaching tests than on evaporation test. The methods applied will be of interest to give answers to the questions about the quantity of possible emissions. Standardisation on leaching started very early. One of the first attempts to quantify the effect of leaching on the remaining efficacy was the German DIN 52176-2 (1941) which was the basis for EN 84 first published by CEN in 1978. A specific German standard for the determination of leachates was published in 1972 (DIN 52172-2), however, the viewpoint was still the efficacy of wood preservatives. With respect to pollution of the environment EN 1250-2 (1995) has to be mentioned, however, this is more or less only a modification of EN 84 and as such not very satisfactory. Evaporation tests started as late as in the 50th mainly in connection with fluorides and later with PCP. Examples for a standard to determine the remaining efficacy are the German Pre-Standard DIN 52172-3 (1971) and EN 73, based on the German standard and first published in 1978. A specific standard for emissions is EN 1250-1 (1995). The reflections presented in the paper consider evaporation as well as leaching tests where the general requirements and the statements to the kind of specimens and to the treatment apply to both types of emissions at the same time. For the test procedure itself, however, different methods are needed.
H Willeitner, R-D Peek
Effect of leaching temperature and water acidity on the loss of metal elements from CCA treated timber in aquatic conditions. Part 2: Semi-industrial investigation
1995 - IRG/WP 95-50040-13
In continuation of previous leaching research on the quantification and modelling of metal elements released from CCA treated timber, a series of experiments has been carried out dealing with the influence of temperature and pH of the relative aquatic environment. The leaching method used is the Dutch prestandard for building materials, a long term static leaching test simulating practical bank-shoring situations. Parameters of study are type of fixation, wood species and specimen profiles. With decreasing water temperature, significantly less leaching of copper, chromium and arsenic is observed. An outdoors/indoors temperature ratio of 0.7 could be established. Increasing acidity of the leaching water mainly enhances the release of copper, whereas chromium and arsenic show a minimum leaching tendency at neutral pH. Both conditioning chamber fixation and steam fixation prove to be effective in fixing the metal elements in the wood substrate. With steam fixed timber, however, a higher loss of copper is observed during the early leaching cycles, due to the presence of copper salts on the wood surface. With regard to specimen profiles, boards in comparison with posts demonstrate a remarkable resistance to leaching of active ingredients, presumably due to the different heartwood/sapwood distribution and the specimen dimensions. In conclusion, the observations made confirm the results obtained from previous leaching studies. Converting the emission data into leaching fluxes, a highly correlated double logarithmic flux formula is regarded the best tool for curve fitting, however, for a limited time span. Other models which are more suitable for extrapolation of emitted quantities over a longer period of time are still under investigation. Likewise, proprotional metal ratios versus retention levels highlight the relativity of experimental data obtained with standard emission tests.
G M F Van Eetvelde, W J Homan, H Militz, M Stevens
Emission of trimethyl borate and methanol from radiata pine (Pinus radiata D. Don)
1995 - IRG/WP 95-30088
Sawn and kiln dried radiata pine conditioned to 3, 6, and 12% moisture content was treated with trimethyl borate (TMB). The treated wood samples were placed in mini-desiccators maintained at 20 or 40°C. The air space within the mini-desiccator was analysed for TMB and methanol. An initial period of emission of TMB and methanol was observed. This was followed by a period of gradual dissipation of both TMB and alcohol. There was an equilibrium of 2 ppm and 60 ppm respectively of TMB and methanol for 12% moisture content timber stored at 20°C. Dissipation was slower for 6% and 3% moisture content timber. Higher temperatures resulted in higher concentrations of TMB and methanol during the emission and dissipation stage.
F J Romero, P Vinden, J A Drysdale