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The effect of added nutrients on growth rate and decay capacity of Serpula lacrymans
1990 - IRG/WP 1427
At the previous meeting a new technique was presented that enables both fungal growth rate and wood decay rate to be measured using the same timber specimen. The technique (IRG/WP/1384) has previously been carried out with 1% malt as the sole nutrient within the small jar that provides the inoculum for this method. Results presented here relate to an additional level of 5% malt, with or without a nitrogen source in the form of ammonium sulphate at either 0.01 g or 1.0 g per litre. Two isolates of Serpula lacrymans (one of European and one of Australian origin) were used at a temperature setting of 20°C. The linear growth front was measured, on the 200 mm long specimens of Pinus radiata sapwood, between 10 and 21 days after the specimens were introduced to the inoculum. Mass loss values of these same specimens were determined after 12 weeks' exposure. Replication comprised three specimens, within each of three large jars, of each treatment. For both strains, increasing the malt level caused some reduction in growth rate, with the addition of nitrogen resulting in no further growth rate changes. In contrast, mass loss of timber was increased for both strains at the higher malt level. Furthermore, for each of the two malt levels tested, the mass loss due to both strains was further increased at the high nitrogen level.
J D Thornton, A McConalogue

On the use of probit analysis for assessing the toxicity of wood preservatives
1974 - IRG/WP 244
To elucidate the general character of the action of the toxic material on the fungus, it is sufficient to carry out preservative tests using the previously described procedure, but in doing so, it is necessary somewhat to change the number of specimens and their arrangement in jars. Five concentrations of toxic material are tested simultaneously. For the testing of one preservative ten jars should be used in each of which are placed 50 specimens, comprising 10 of each of the five concentrations. The proposed arrangement of the specimens in jars makes due allowance both for the variation in the reaction of the individual sections of the mycelium in one jar (ten specimens) and for the variation in the reaction of the fungus in the different jars (ten groups of specimens). The effect of each concentration of toxic material on the fungus may, therefore, be assessed from the result of observing its reaction on a hundred specimens tested in all ten jars. With this procedure the author investigated the toxicity to Coniophora of sodium fluoride, sodium chloride and sodium silicofluoride, copper sulphate, zinc chloride, ammonium fluoride and ammonium pentaborate. The results are given in Table 1. Complete curves of the toxic effect were not obtained for all the formulations, but for the majority of them levels of transition from incomplete to practically complete protection of the timber against destruction by the fungus were established. The test results for sodium fluoride, using the given procedure, are represented graphically in Fig.1 (curve 2). It can be seen from Fig.1 that the change of reaction of Coniophora in timber containing different amounts of NaF is well described by an S-shaped curve, similar to the integral function of a normal distribution. Similar graphs are also obtained when testing other preservatives. The nature of the curve shows yet again that different probit-analysis methods may be used when testing preservatives in timber. Fig.3 shows the probit curves of the effect of sodium fluoride. Since in our case the curve is symmetrical and not lengthy, there was no need to use a logarithmic scale for the axis of abscissae. It can be seen from Fig.3 that, by using a normal distribution as a model for transforming the NaF toxic effect curve, rectilinear graphs are obtained. With such graphs it is easy to find the different levels of timber protection, and also to assess the variation of the reaction of the wood-destroying fungus by computing the mean dose and the standard deviation by the known methods of probit-analysis. From the probit v. NaF content graph (Fig.3) is found the amount of sodium fluoride necessary for protecting the timber of pine sapwood against destruction by Coniophora in 95 per cent of cases. It is 0.168 kg/m³. When determining the said level of protection by the author's proposed procedure, the value obtained was 0.136 kg/m³, i.e. 0.032 kg/m³ less. This is due to the fact that in the latter case the number of specimens tested was comparatively small. The proposed method, therefore, gives an overall picture of the protection of the timber by a specific preservative against the action of wood-destroying fungus and enables the amount of toxic material, which should be selected for a more detailed investigation by the previously reported procedure, to be determined.
D A Belenkov

Effect of fire retardants (monoammonium phosphate and diammonium phosphate, mixture of monoammonium phosphate and borax and ammonium sulphate) on beech wood with dipping and Lowry methods
2006 - IRG/WP 06-40350
In this study, the possibilities of using four kinds of chemicals as fire retardants with 12% concentration for beechwood (Fagus orientalis Lipsky) was surveyed. Providing testing samples that are related to the measurement of fire resistance properties according to JIS A-1321-1975 standard were evaluated. Wood samples were impregnated with Lowry and dipping methods. In this study, samples impregnated with diammonium phosphate by Lowry method had the best fire resistance properties. Wood samples impregnated with diammonium phosphate had the highest compression parallel to grain and highest resistance of hardness and samples impregnated by ammonium sulphate had the least total shrinking.
M Akhtari, D Parsapajouh, M Arefkhani

Effect of fire retardants (monoammonium phosphate and diammonium phosphate, mixture of monoammonium phosphate and borax and ammonium sulphate) on beech wood with dipping and Lowry methods
2006 - IRG/WP 06-40350
In this study, the possibilities of using four kinds of chemicals as fire retardants with 12% concentration for beechwood (Fagus orientalis Lipsky) was surveyed. Providing testing samples that are related to the measurement of fire resistance properties according to JIS A-1321-1975 standard were evaluated. Wood samples were impregnated with Lowry and dipping methods. In this study, samples impregnated with diammonium phosphate by Lowry method had the best fire resistance properties. Wood samples impregnated with diammonium phosphate had the highest compression parallel to grain and highest resistance of hardness and samples impregnated by ammonium sulphate had the least total shrinking.
M Akhtari, D Parsapajouh, M Arefkhani

Observations on the colonization of freshly-felled timber treated with prophylactic chemicals by mould and sapstain fungi
1989 - IRG/WP 1394
Field tests using freshly felled pine sapwood were set up to determine the effectiveness of a range of antisapstain compounds and to study the problems of colonization by mould and sapstain fungi. Differences were recorded both in the overall performance of the compounds and also their selectivity in controlling specific fungal types. These results were found to be useful in gaining a better understanding of biocide - fungal interactions.
G R Williams, D A Lewis

The influence of previous anti-blue-stain preservative treatments on the fixation of CC in spruce
1997 - IRG/WP 97-30134
Freshly cut and kiln dried spruce boards were treated with 4 different anti-blue stain preservatives (ABP). After a period of 10 days allowing the samples to dry and fixate, the samples were treated with CC (chromium, copper formulation) using a vacuum pressure cycle. After impregnation the wood was steam fixed. A submersion leaching test showed differences in the leachable quantity of copper and chromium. When related to the retention of both salts after impregnation, no differences could be found between samples previously treated with anti-blue-stain preservatives and untreated samples. However, the retention of CC diminished significantly by application of quaternary ammonium compounds.
M Van der Zee, W J Homan

Kinetic modelling of adsorption of quaternary ammonium compounds by Scots pine wood sawdust (Pinus sylvestris L.)
2005 - IRG/WP 05-30369
The adsorption of new quaternary ammonium compounds from aqueous solutions onto Scots pine wood (Pinus sylvestris L.) sawdust was studied. The pseudo first- and second- order kinetic models were used for the mathematical description of the sorption dynamic process of QACs onto wood. The highest correlation coefficients were obtained for the pseudo-second order kinetic model, those suggest that chemisorption is involved in the adsorption process.
J Zabielska-Matejuk

Conditions for basidiospore production in the brown rot fungus Gloeophyllum separium in axenic culture
1984 - IRG/WP 1232
Attempts to control and optimize the production of hymenial structures and basidiospore production in Gloeophyllum sepiarium in axenic culture resulted in the proposal of the following conditions as being suitable. The dikaryotic mycelia originally isolated from basidiocarps could consistently be induced to produce hymenial structures and pure basidiospore collects if illuminated by near ultraviolet light with emission maximum at 355 nm ("black light") at a temperature of 15°C on a chemically defined medium, where the concentration of the carbon and the nitrogen sources were shown to be of critical significance. The necessary conditions for basidiospore production in lignicolous fungi in general are is briefly discussed.
J Bjurman

The performance of wood preservatives in soil-bed soft rot tests
1993 - IRG/WP 93-20007
Testing the efficacy of wood preservatives in soil is recognised as a fundamental part of the assessment of long-term wood protection in ground contact. Laboratory based tests can provide a hazardous environment in which a preservative can be challenged by a range of micro-organisms. This paper presents the results of tests carried out to investigate the performance of wood preservatives in a wet soil environment using both strength loss and weight loss as the main criteria for performance assessment.
G R Williams, S Caswell

Proposed degradation pathway for quaternary ammonium compounds by mould fungi
1996 - IRG/WP 96-10166
One group of chemicals that has attracted considerable attention as potential wood preservatives are the quaternary ammonium compounds (QACs). Based upon results of previous research this study confirmed the degradation pathway employed in QAC-tolerant fungi. For this experiment the two dialkylammonium compounds didecyldimethylammonnium chloride and dioctyldimethylammonium chloride were used. QAC-treated wood blocks were inoculated with the tolerant fungi Gliocladium roseum and Verticillium bulbillosum. After incubation the remaining QACs were extracted with acidified acetonitrilic and HPLC was used to quantify and detect the degradation products.
J L Bürgel, J Dubois, J N R Ruddick

Soil-bed studies (Part 3): A cause of failure of multisalt preservatives following soil-bed exposure
1983 - IRG/WP 3261
P Vinden, J F Levy, D J Dickinson

The effect of temperature on the rate of fixation of an alkyl ammonium compound (AAC) wood preservative
1984 - IRG/WP 3293
The rate of fixation of an alkyl ammonium compound wood preservative was measured by soaking samples of wood wool in various preparations of the preservative for arbitrary times followed by immediate leaching in water. The wood wool was then analysed for residual preservative. The results indicated that fixation was very rapid and increased at higher temperatures.
P Vinden

Interaction mechanisms of F/Cr/As/B type preservative and wood
1981 - IRG/WP 3183
The paper reports results of investigations on the fixation of the components of a F/Cr/As/B preservative in wood and its lignin and cellulosic components.
N Ermush, I Andersone

Lignin-copper, a new wood preservative without arsenic and chromium
1992 - IRG/WP 92-3702
A more environmentally sound treatment for wood with preservatives containing no arsenic or chromium, has been developed and studied on a laboratory scale. The method involves a first step impregnation with an aqueous solution containing modified, water-soluble kraft lignin followed by a second step involving impregnation with a copper salt solution to give fixation of the lignin into a water-insoluble form and to achieve complementary protection. The two steps can be performed without intermediate drying of the wood in a conventional reactor for vacuum-pressure impregnation. The treatment has been shown to give good protection against degrading fungi, tunnelling bacteria and termites, and a lower growth of mould on the wood surface. Field tests (NTR test) indicate, after 4 years of exposure, very good protection gained by this new treatment. Fibre and particle boards made from wood fibres and wood particles, treated with this method show increased dimensional stability and rot resistance.
B Ohlsson, R Simonson

Effect of borate on uptake and efficacy of an anti-sapstain treatment
2005 - IRG/WP 05-30380
The potential for using borates to enhance uptake and efficacy of propiconazole-based anti-sapstain chemicals was assessed on ponderosa pine sapwood wafers. Borates had no consistent effect on either net solution absorption or propiconazole distribution in the wood. Even small amounts of borate, however, markedly improved the performance of propiconazole against fungal discoloration. These results are consistent with previous tests of borate addition to other fungicides and highlight the potential for using less expensive ingredients to boost the performance of more costly biocides.
Jianju Luo, Hua Chen, J J Morrell

Antifungal properties of new quaternary ammonium and imidazolium salts against wood decay, staining and mould fungi
2004 - IRG/WP 04-30347
The biological activity of twenty-four potential wood preservatives – imidazolium and quaternary ammonium salts with a modified anion structure was determined employing screening agar-plate and agar-block methods. Experiments were carried out on Scots pine (Pinus sylvestris L.) wood. The aim of the performed studies was to investigate the effect of structure modification of IC and QAC with organic anions or copper (ll) and zinc complexes on their biological activity against wood decay, staining and mould fungi. The fungicidal value of new compounds for Coniophora puteana ranged from 0.64 kg/m3 to 2.2 kg/m3. Aspergillus niger turned out to be the most resistant fungus to the action of modified IC and QACs, whereas Sclerophoma pityophila was effectively inhibited by the examined salts. The performed soil-block tests showed that the IC and QAC were leached from the experimental wood in conditions of contact with moist soil and revealed their fungal detoxification by mould fungi, especially by Gliocladium roseum. Observations made using the scanning electron microscope of the colonization and decay of treated wood by mould fungi confirmed tolerance of mould fungi to QACs.
J Zabielska-Matejuk, W Wieczorek

Remedial treatment of joinery. Comparison of distribution of organic solvent preservative and ammonium bifluoride
1978 - IRG/WP 3115
It is some years since it was recognised in the United Kingdom that there was a problem of premature decay in untreated external joinery. Consequently, recommendations for preservative treatment were made by the Building Research Establishment, Princes Risborough Laboratory. In addition, the National House-Building Council has also included the preservative treatment of external joinery in its requirements. Thus, a large proportion of external joinery manufactured in the U.K. is now preservative treated, mainly in double vacuum impregnation plants. There still remain, however, relatively new buildings where preservative treatment has not been specified and where fungal decay is a problem. Decay occurs most frequently in the lower horizontal members such as cills, and the lower rails of opening lights. The damage is often most severe at the joints, where entry of water is facilitated by exposure of end grain. In some circumstances such as in Local Authority buildings where some of the more exposed joinery has already decayed, it has been considered economic to treat the remaining sound or near-sound joinery in situ in order to prevent future attack and to arrest any slight decay that may already be present. This treatment is normally applied by injecting organic solvent preservative under pressure in the region of the joints and where considered necessary along the lower horizontal member. As an alternative method of treatment, we have investigated the possible use of ammonium bifluoride, since diffusion of gaseous hydrogen fluoride may be expected to penetrate more extensively into wet timber than organic solvent preservative. The work described below was carried out in order to assess the comparative penetration of fluoride and organic solvent preservative in redwood (Pinus sylvestris).
J M Taylor

Evaluation of an alkyl ammonium compound as a fungicide to control sapstain and mould during diffusion storage
1984 - IRG/WP 3282
An alkyl ammonium compound ('Akzo' ES 255) was evaluated for its effectiveness against mould and sapstain during diffusion storage of boron-treated rubber wood. Though ES 255 at 1.0% concentration was effective against mould (71%) and sapstain (89%) it is less satisfactory compared to 0.5% sodium pentachlorophenoxide against mould (92%) and sapstain (98%).
R Gnanaharan

The Chemical and Biological Properties of Polymeric Betaine
2009 - IRG/WP 09-30512
Didecyl polyoxyethyl ammonium borate (DPAB), also known as Polymeric Betaine, was developed as a co-biocide for chromium-free copper based wood preservatives in Europe in the 1980’s. DPAB as a wood preservative has been reported previously. This paper summarizes the chemical, physical, and biological properties of DPAB.
H Härtner, S Schmitt, Futong Cui, H M Barnes

A potential anti-sapstain chemical for sawmills
1984 - IRG/WP 3300
Several biocidal formulations were tested under laboratory conditions in order to discover an alternative antisapstain chemical to chlorophenoxides. The formulations tested were experimental water solutions containing a quaternary ammonium chloride, a commercial fungicide and/or a sodium salt of some carboxylic acids. The effect of sodium carbonate and borax decahydrate in mixture with a quaternary compound was also examined. The best cost-effectiveness was obtained with trimethylcocoammoniumchloride in combination with a sodium salt of a branched-chain aliphatic acid. This finding was later confirmed in pilot and mill scale tests.
I A Linderborg

Sterilization of mango wood (Mangifera indica L.) without heat
1995 - IRG/WP 95-30065
Researches revealed that boric acid can play an important role for sterilizing wood instead of heating. Wet (green) mango boards (Mangifera indica L.) were pressure treated in treating cylinder at initial vacuum of 508 mm Hg for 15 minutes and impregnation pressure of 7 kg/cm² for 4 hours with 5% solution (w/v) of 1:1:1 commercial grade (95% pure) sodium dichromate, copper sulphate and boric acid. Penetratons of copper sulphate and boric acid were examined by using standard reagents. Copper sulphate penetrated superficially but boric acid penetrated completely through the boards. In most hazardous conditions during rainy season the treated boards were saved like heatsterilized boards from the attack of decay fungi and insects. Untreated boards (control) were found decayed and damaged within three months with the decrease of strength significantly. Where heatsterilization and kiln-drying are practically impossible during rainy season, wet timbers can be stored after impregnating those with at least 2% solution (w/v) of boric acid which diffuses through wet wood successfully and can protect wood from decay fungi, and wood destroying borers.
A K Lahiry

Natural exposure weathering tests: Their role in the assessment of wood preservative efficacy
1993 - IRG/WP 93-20006
Previous work has demonstrated the potential and usefulness of natural ageing procedures in e evaluation of wood preservative efficacy. This results from the combination of physico-chemical influences and microbiological interactions with both substrate and wood preservative. In this paper, results are presented for a range of biocide types. Discussions are centred on the value of natural exposure weathering tests for preservative efficacy assessment and the importance of biological persistence in the design of effective wood preservatives.
G R Williams, J Brown

The fungal degradation of quaternary ammonium compounds in wood
1998 - IRG/WP 98-10263
This work focuses on the biodegradation of didecyldimethylammonium chloride (DDAC) by the mould fungus Gliocladium roseum within a woody matrix. Three sawdust types, distinguished by their treatment and amount of DDAC retained, were inoculated with the fungus and their DDAC loss was measured over 11 weeks. The rates of degradation varied depending on the sawdust; however, a significant loss of DDAC was observed for all three. A metabolic by-product coincided with the fungal degradation of DDAC. The metabolite was separated using preparative HPLC and identified by proton-NMR and infrared spectroscopy to be a hydroxylated QAC.
J W Dubois, J N R Ruddick

Composting of waste building up in sawmill dipping basins
1990 - IRG/WP 3570
We have studied composting of waste building up in dipping basins at sawmills although this waste can also be disposed of by incineration. Controlled composting within the sawmill area seems to be a feasible method. Another possibility is to accomplish composting directly at the local dumping site. Waste containing antistain chemicals is generally classed as hazardous. It cannot therefore be placed as such at common dumps. However after successful composting the permission to do so can probably be obtained. The composted dipping basin waste might also be suitable as land filling or in some cases as soil improvement material - at least in parks and green belt areas.
I A Linderborg, U Ek

Adsorption of ACQ and CuMEA Wood Preservatives in Red pine
2005 - IRG/WP 05-30374
The rates of stabilization or fixation of ACQ subcomponents (CuO, DDAC and MEA) in red pine (Pinus resinosa) were compared for different solution concentrations (0.75%, 1.5%, 2.25% and 3% ACQ-D) and post treatment conditioning temperatures. Preservative solutions were impregnated into red pine sapwood by a full-cell treatment. Copper and MEA adsorptions from copper monoethanolamine solutions without DDAC were also evaluated for comparison. After the treatments, samples were conditioned without drying either at 22° C for seven weeks or at 50° C for one week. At different times after treatment, expressate from the specimen blocks was analyzed for copper, DDAC and MEA. Copper and MEA adsorption by the wood cell walls followed similar trends. The equilibrium copper adsorption ranged from 44% at high ACQ retentions to about 95% for the lowest retention while the values in the CuMEA system were slightly higher for the higher retentions, ranging from about 54% to 93%. This suggests that DDAC may compete with CuMEA for reaction sites at high ACQ concentrations. Adsorption of DDAC into the wood cell wall matrix was rapid; at all solution concentrations, more than 80% of DDAC was adsorbed by red pine sapwood within minutes after treatment.
C Tascioglu, P A Cooper, Y T Ung

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