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Miha Humar - One of the best experts on this subject based on the ideXlab platform.
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performance of copper treated utility poles and posts used in service for several years
International Biodeterioration & Biodegradation, 2017Co-Authors: Miha Humar, Nejc ThalerAbstract:Abstract Copper based Wood Preservatives are among the most important Wood Preservatives for heavy-duty applications. Wood treated with copper-based Preservatives performs excellently if applied according to preservative specifications. If used improperly, premature failures can appear. In order to elucidate the properties of copper treated Wood in use, utility poles and posts treated with copper-based Preservatives were investigated. Poles were cut into smaller specimens, and copper and chromium penetration, retention, mechanical properties, extractive content, short-term water uptake and fungicidal properties were then determined. The results clearly showed that Wood retains its properties if treated with sufficient amounts of copper-based Wood Preservatives. Insufficient amounts of Preservatives applied result in premature failures of Wood commodities. Regardless of the type of Wood preservative used, the central part of spruce Wood poles and piles is the weakest point, where the majority of the failures occurs.
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Montan wax improves performance of boron-based Wood Preservatives
International Biodeterioration & Biodegradation, 2009Co-Authors: Bostjan Lesar, Polona Kralj, Miha HumarAbstract:Abstract Importance of boron compounds in Wood preservation is increasing due to their low environmental impact, high efficacy and the fact that many other active ingredients have been removed from the market after the introduction of the Biocidal Products Directive. The most important drawback of boron is prominent leaching in wet environment. In order to improve their fixation, and performance against Wood decay fungi, boric acid was combined with montan wax emulsion. Possible synergistic effects of boric acid and montan wax were determined according to modified EN 113 procedure. Norway spruce and beech Wood specimens were exposed to three white rot ( Trametes versicolor , Pleurotus ostreatus and Hypoxylon fragiforme ) and brown rot Wood decay fungi ( Gloeophyllum trabeum , Antrodia vaillantii and Serpula lacrymans ) for 12 weeks. Boron leaching from vacuum/pressure treated Norway spruce Wood was determined according to the continuous (EN 84 and ENV 1250-2) and non-continuous (OECD and prCEN/TS 15119-1) procedures. Boron was determined with ICP mass spectrometry in collected leachates. The results of the fungicidal tests clearly showed that montan wax emulsion and boric acid act synergistically against tested Wood decay fungi. Approximately 50% lower boric acid retentions are required in combination with montan wax emulsions to achieve sufficient protection against Wood rotting fungi. However, it is even more important that all leaching tests performed proved that the addition of montan wax decreased boron leaching from impregnated specimens for 20% up to 50%.
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influence of dipping time on uptake of preservative solution adsorption penetration and fixation of copper ethanolamine based Wood Preservatives
European Journal of Wood and Wood Products, 2009Co-Authors: Miha Humar, Bostjan LesarAbstract:Copper-ethanolamine based Wood Preservatives are the most important products for protection of Wood in use class III and IV applications. These Preservatives can be applied using different procedures. One of them is dipping, a method which is predominantly used in less industrialised countries. The most important parameter, that influences the quality of this treatment, is dipping time. Influence of various dipping times on copper retention, adsorption, penetration, colour of the specimens and copper fixation was examined. In this paper copper-ethanolamine solutions of two different concentrations were utilised (cCu=0.05% or 0.25%). The results showed that longer dipping treatments resulted in higher uptakes of preservative solution, better penetrations and lower leaching of copper-ethanolamine based Wood Preservatives from Norway spruce Wood. After one week of dipping, samples retained on average 275 kg/m3 of preservative solution, copper active ingredients penetrated on average 3 mm into the specimens, and only 2.3% of copper was emitted from Wood impregnated with aqueous solution of the higher concentration, when subjected to ENV 1250 leaching procedure.
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fungicidal properties of individual components of copper ethanolamine based Wood Preservatives
International Biodeterioration & Biodegradation, 2008Co-Authors: Miha Humar, Bostjan LesarAbstract:Abstract The importance of copper–ethanolamine-based Wood Preservatives is increasing. These Preservatives usually consist of copper as a fungicide, ethanolamine as a fixative, and secondary fungicides (boron, triazoles) and other additives (water repellents, fixatives, wax emulsions, etc.). Questions arise as to how each of these ingredients interacts with Wood-decay fungi, and whether there are any synergistic effects between the components. In order to elucidate these questions, Norway spruce Wood specimens were impregnated with five different aqueous solutions consisting of one single component only and of complete formulation of five different concentrations. These specimens were exposed to two brown-rot fungi, Antrodia vaillantii and Gloeophyllum trabeum , as well as to the white-rot fungus Trametes versicolor for 8 weeks according to mini block procedure. In parallel, petri dishes with nutrient medium containing different quantities of ingredients and of complete Wood preservative were inoculated with the same fungal species, and their growth was compared with growth on media without chemicals. The results showed that both experimental methods give similar results. In general, there was no synergistic effect determined. Ethanolamine did not decrease fungicidal properties of the system, while on the other hand octanoic acid has a positive effect on the growth of brown-rot fungi. The minimal effective concentration of tested copper–ethanolamine preservative was determined by the minimum effective concentration of the most fungi-toxic ingredient.
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performance of waterborne cu ii octanoate ethanolamine Wood Preservatives
Holzforschung, 2003Co-Authors: Miha Humar, Franc Pohleven, Marjeta Sentjurc, Marjan Veber, Polona Razpotnik, Rebecca Pogni, M PetricAbstract:Summary Various aqueous Wood preservative solutions containing Cu(II) in the form of copper(II) sulphate or copper(II) octanoate, ethanolamine and in one case octanoic acid were investigated by spectrophotometry, polarography and Electron Paramagnetic Resonance (EPR) spectroscopy. Results have shown the same coordination environment around Cu(II) in all solutions with ethanolamine. Computer simulation of the EPR spectra also revealed that the coordination in the first coordination sphere of copper is the same at low concentration of ethanolamine. At 20% ethanolamine concentration, a mixture of two complexes (one with two nitrogens and the other with three) could be detected. The active compound in the investigated ethanolamine containing solutions is the same when previously synthesised copper(II) octanoate was used, or when copper(II) sulphate and octanoic acid were utilized instead. Fungicidal and leaching experiments with the treated Wood resulted in the same conclusion: it is not necessary to use pre-synthesised copper(II) octanoate for the preparation of waterborne copper/ethanolamine Wood Preservatives. Preservative preparation time and costs can be reduced by simply dissolving copper(II) sulphate and octanoic acid in aqueous ethanolamine solutions.
In Yang - One of the best experts on this subject based on the ideXlab platform.
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antifungal efficacy of environmentally friendly Wood Preservatives formulated with enzymatic hydrolyzed okara copper or boron salts
Environmental Toxicology and Chemistry, 2011Co-Authors: Hoyong Kim, Sye Hee Ahn, Ingyu Choi, Hanseob Jeong, Youngho Yoon, Byeong Cheol Min, In YangAbstract:Okara, an organic waste product obtained from soy milk production, was used with copper chloride or sodium borate to formulate new Wood Preservatives as a substitute for expensive Wood Preservatives, such as copper-azole-based Preservatives and ammoniacal copper quaternary. Before formulating the Preservatives, okara was hydrolyzed by enzymes (cellulase, pectinase, and protease) to augment penetration and fix the biocide salts of the Preservatives into Wood blocks. The Preservatives were injected into Wood blocks by vacuum pressure to measure the treatability of the Preservatives. The treated Wood blocks were placed in hot water for 3 d to measure leachability. The treatability and leachability of the Preservatives were affected by the type and loading amount of enzymes and the addition of sodium borate into okara-based Wood preservative formulations. The treatability and leachability of the Preservatives formulated with copper chloride and okara hydrolysates were 63.38 and 3.15%, and those of the Preservatives with copper chloride, okara hydrolysates, and sodium borate were 61.47 and 3.32%, respectively. Despite the hot water leaching, Wood blocks treated with Preservatives formulated with 2% cellulase, pectinase, and protease hydrolyzed okara, CuCl(2), and sodium borate showed only 1.98% average weight loss against Fomitopsis palustris over 12 weeks. Microscopic observation revealed how okara-based Preservatives work in Wood blocks. Okara has potential as a raw material for cost-effective and environmentally friendly Wood Preservatives.
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environmentally friendly Wood Preservatives formulated with enzymatic hydrolyzed okara copper and or boron salts
Journal of Hazardous Materials, 2010Co-Authors: Sye Hee Ahn, Ingyu Choi, Gyuseong Han, Hanseob Jeong, Ki Woo Kim, Youngho Yoon, In YangAbstract:Novel biocides, such as copper azole (CuAz) and ammoniacal copper quaternary (ACQ), are extensively used as substitutes for chromate copper arsenate (CCA) in Wood preservation. However, the expense of these biocides has necessitated the development of cost-effective and environmentally friendly Wood Preservatives. This study was conducted to investigate the effectiveness against decaying fungi of the Preservatives formulated with enzymatic-hydrolyzed okara (OK), which is an organic waste produced from the manufacture of tofu, CuCl2 (CC) and/or Na2B4O7·10H2O (B). With the addition of NH4OH as a dissociating agent, the addition of OK facilitated the target retention of most of the OK/CC and OK/CC/B preservative formulations in Wood blocks. The OK-based Wood Preservatives (OK-WPs) were stable against hot-water leaching. When compared with control and CC-treated Wood blocks, the leached Wood blocks treated with OK/CC and OK/CC/B formulations showed excellent decay resistance against both Postia placenta and Gloeophyllum trabeum, especially when OK was hydrolyzed by Celluclast at a loading level of 0.1 ml/g. Scanning electron microscopy (SEM) and SEM-energy dispersive X-ray (SEM-EDX) spectrometry analyses demonstrated that preservative complexes, such as OK–CC and OK–CC–B, existed in the Wood blocks treated with OK/CC and OK/CC/B formulations. This study results support the potential application of OK-WPs as environmentally friendly Wood Preservatives capable of replacing CuAz and ACQ.
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effects of acid concentration and the addition of copper boron salts on the efficacy of okara based Wood Preservatives
Journal of the Korean Institute of Resources Recycling, 2009Co-Authors: Hanseob Jeong, Sye Hee Ahn, Ingyu Choi, Hoyong Kim, Gyuseong Han, In YangAbstract:This research was carried out to formulate environmentally friendly Wood Preservatives with okara and to investigate the effects of the acid concentration used for the hydrolysis of okara and salt type on the decay resistance of the Preservatives. Okara-based Preservatives were formulated with okara hydrolyzates, which were prepared with 0, 1%, and 2% sulfuric acid at for 1 hr, and salts such as copper chloride and/or sodium borate. The Preservatives were treated into Wood blocks by vacuum-pressure method, and then the treated Wood blocks were leached in hot water for 72 hrs. The fungal treatments of the leached Wood blocks were conducted by brown-rot fungus, Tyromyces palustris, and white-rot fungus, Trametes versicolor, to examine the decay resistance of the Preservatives. As the acid concentration used for hydrolysis of okara increased, the treat-ability and decay resistance of the Preservatives were improved, which the leachability was decreased. Wood blocks treated with the okara/copper or okara/copper/borax, showed very good decay resistance against T. palustris and T. versicolor. However, Wood blocks treated with the okara/borax and okara-free preservative solutions, were observed the fungal decay by T. palustris. The optimal conditions for the preparation of okara-based Wood Preservatives were formulated with okara hydrolyzed with 1% sulfuric acid, copper chloride and borax.
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efficacy of Wood Preservatives formulated from okara with copper and or boron salts
Journal of Wood Science, 2008Co-Authors: Sye Hee Ahn, Ingyu Choi, Hoyong Kim, In YangAbstract:As a substitute for high-cost copper azole (CuAz) and alkaline copper quaternary (ACQ) Wood Preservatives, alternative Wood Preservatives were formulated with okara, which is an organic waste from the production of tofu, and copper chloride and/or borax. Each preservative was used in treatment of Wood blocks in a reduced-pressure method to measure its treatability. The treated Wood blocks were placed in hot water for 3 days to examine the stability of the Preservatives against hot-water leaching. The Preservatives successfully penetrated into Wood blocks, probably due to the use of ammonium hydroxide as a dissociating agent. However, the stability of okara-based Preservatives dropped as the concentration of acid in the solutions used for hydrolysis of okara increased. The treatability and leachability of the Preservatives were not affected by hydrolysis temperature but were negatively affected by the addition of borax. Leached Wood blocks treated with okara-based Preservatives and exposed to decay fungi Gloeophyllum trabeum and Postia placenta over 12 weeks showed good decay resistance. Okara-based Wood Preservatives can protect Wood against fungal attack as effectively as CuAz, and have potential for use as environmentally friendly Wood Preservatives.
Bostjan Lesar - One of the best experts on this subject based on the ideXlab platform.
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Montan wax improves performance of boron-based Wood Preservatives
International Biodeterioration & Biodegradation, 2009Co-Authors: Bostjan Lesar, Polona Kralj, Miha HumarAbstract:Abstract Importance of boron compounds in Wood preservation is increasing due to their low environmental impact, high efficacy and the fact that many other active ingredients have been removed from the market after the introduction of the Biocidal Products Directive. The most important drawback of boron is prominent leaching in wet environment. In order to improve their fixation, and performance against Wood decay fungi, boric acid was combined with montan wax emulsion. Possible synergistic effects of boric acid and montan wax were determined according to modified EN 113 procedure. Norway spruce and beech Wood specimens were exposed to three white rot ( Trametes versicolor , Pleurotus ostreatus and Hypoxylon fragiforme ) and brown rot Wood decay fungi ( Gloeophyllum trabeum , Antrodia vaillantii and Serpula lacrymans ) for 12 weeks. Boron leaching from vacuum/pressure treated Norway spruce Wood was determined according to the continuous (EN 84 and ENV 1250-2) and non-continuous (OECD and prCEN/TS 15119-1) procedures. Boron was determined with ICP mass spectrometry in collected leachates. The results of the fungicidal tests clearly showed that montan wax emulsion and boric acid act synergistically against tested Wood decay fungi. Approximately 50% lower boric acid retentions are required in combination with montan wax emulsions to achieve sufficient protection against Wood rotting fungi. However, it is even more important that all leaching tests performed proved that the addition of montan wax decreased boron leaching from impregnated specimens for 20% up to 50%.
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influence of dipping time on uptake of preservative solution adsorption penetration and fixation of copper ethanolamine based Wood Preservatives
European Journal of Wood and Wood Products, 2009Co-Authors: Miha Humar, Bostjan LesarAbstract:Copper-ethanolamine based Wood Preservatives are the most important products for protection of Wood in use class III and IV applications. These Preservatives can be applied using different procedures. One of them is dipping, a method which is predominantly used in less industrialised countries. The most important parameter, that influences the quality of this treatment, is dipping time. Influence of various dipping times on copper retention, adsorption, penetration, colour of the specimens and copper fixation was examined. In this paper copper-ethanolamine solutions of two different concentrations were utilised (cCu=0.05% or 0.25%). The results showed that longer dipping treatments resulted in higher uptakes of preservative solution, better penetrations and lower leaching of copper-ethanolamine based Wood Preservatives from Norway spruce Wood. After one week of dipping, samples retained on average 275 kg/m3 of preservative solution, copper active ingredients penetrated on average 3 mm into the specimens, and only 2.3% of copper was emitted from Wood impregnated with aqueous solution of the higher concentration, when subjected to ENV 1250 leaching procedure.
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fungicidal properties of individual components of copper ethanolamine based Wood Preservatives
International Biodeterioration & Biodegradation, 2008Co-Authors: Miha Humar, Bostjan LesarAbstract:Abstract The importance of copper–ethanolamine-based Wood Preservatives is increasing. These Preservatives usually consist of copper as a fungicide, ethanolamine as a fixative, and secondary fungicides (boron, triazoles) and other additives (water repellents, fixatives, wax emulsions, etc.). Questions arise as to how each of these ingredients interacts with Wood-decay fungi, and whether there are any synergistic effects between the components. In order to elucidate these questions, Norway spruce Wood specimens were impregnated with five different aqueous solutions consisting of one single component only and of complete formulation of five different concentrations. These specimens were exposed to two brown-rot fungi, Antrodia vaillantii and Gloeophyllum trabeum , as well as to the white-rot fungus Trametes versicolor for 8 weeks according to mini block procedure. In parallel, petri dishes with nutrient medium containing different quantities of ingredients and of complete Wood preservative were inoculated with the same fungal species, and their growth was compared with growth on media without chemicals. The results showed that both experimental methods give similar results. In general, there was no synergistic effect determined. Ethanolamine did not decrease fungicidal properties of the system, while on the other hand octanoic acid has a positive effect on the growth of brown-rot fungi. The minimal effective concentration of tested copper–ethanolamine preservative was determined by the minimum effective concentration of the most fungi-toxic ingredient.
Francis W. M. R. Schwarze - One of the best experts on this subject based on the ideXlab platform.
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biological control of Wood decay basidiomycetes using trichoderma spp
2020Co-Authors: Javier Ribera, Francis W. M. R. SchwarzeAbstract:Abstract Wood is still one of the most used construction materials due to its abundancy, strength-to-weight ratio, production costs, and environmental benefits. However, as Wood is biodegradable, it has a limited service life. Wood products in ground contact have to be treated with Cu-based Wood Preservatives owing to the favorable conditions for Wood decay, e.g., soft rot fungi. However, a range of Wood destroying fungi have developed resistance mechanisms against Cu-based Wood Preservatives formulations. Screening of a Trichoderma strain with a highly antagonistic potential against Wood destroying basidiomycetes maybe promising sustainable integrated Wood protection strategy in combination with chromium-free Wood Preservatives.
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non biocidal preservation of Wood against brown rot fungi with a tio2 ce xerogel
Green Chemistry, 2018Co-Authors: Francis W. M. R. Schwarze, Javier Ribera, Markus Heeb, Huizhang Guo, Erik Valentine Bachtiar, Ingo BurgertAbstract:The use of Wood as an eco-friendly building material requires the development of environmentally benign Wood Preservatives, which are ideally non-toxic during and after the service life. However, too little is known about the protection of Wood against Wood decay fungi using non-biocidal methods, and as a result, simple but effective methods that increase the service life without environmental or health risks are still rare. A novel Wood protection method is described that is based on a titanium isopropoxide gel, and cerium(IV) ammonium nitrate, as a stabilizer for the treatment of Wood. The hydrolysis of titanium isopropoxide is initiated by the OH-groups of Wood, as well as the moisture in the Wood cell wall, and subsequently results in a cerium-doped TiO2 layer, which not only seals the Wood surface from direct exposure to hydrolytic enzymes but also occludes the micro/nano-pores of the Wood cells. The cerium dopant acts as a radical scavenger that quenches the hydroxyl radicals in the initial stage. Our studies revealed that Norway spruce Wood can be better protected against Wood decay by Gloeophyllum trabeum, Rhodonia placenta and Coniophora puteana. The TiO2/Ce xerogel coating also improves resistance against weathering, as modified specimens showed good anti-fungal properties even after accelerated weathering treatments. This novel Wood protection method provides a greener and safer alternative to traditional biocidal Wood Preservatives and has the potential to extend the service life of Wood materials particularly in outdoor applications as well as for archaeological Wood conservation.
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integrated control of Wood destroying basidiomycetes combining cu based Wood Preservatives and trichoderma spp
PLOS ONE, 2017Co-Authors: Francis W. M. R. Schwarze, Javier Ribera, Siegfried Fink, Maria Del Carmen BasAbstract:The production of new generation of Wood Preservatives (without addition of a co-biocide) in combination with an exchange of Wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of Wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against Wood Preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against Wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on Wood colonization and degradation by five Wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of Wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based Preservatives was also examined by mass loss and histological changes in the Wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on Wood specimens against four Wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based Wood Preservatives demonstrated that after 9 months incubation with two Wood destroying basidiomycetes, Wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55–65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0–25%). Histological studies on one of the Wood destroying basidiomycetes revealed typical decomposition of Wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in Wood specimens previously exposed to T. harzianum. It is concluded that carefully selected Trichoderma isolates can be used for integrated Wood protection against a range of Wood destroying basidiomycetes and may have potential for integrated Wood protection in the field.
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resistance of bioincised Wood treated with Wood Preservatives to blue stain and Wood decay fungi
International Biodeterioration & Biodegradation, 2011Co-Authors: Mark Schube, Thomas Volkme, Christia Lehringe, Francis W. M. R. SchwarzeAbstract:Bioincising is a biotechnological process that aims at the improvement of Wood preservative uptake in Wood species with a low permeability, such as Norway spruce (Picea abies (L.) Karst). The process is based on a short-term pre-treatment with white-rot fungus Physisporinus vitreus. During incubation the membranes of bordered and half bordered pits are supposed to be degraded by fungal activity resulting in a better treatability of the Wood structure for Wood Preservatives. In the present study, first of all the resistance of bioincised Norway spruce heartWood and untreated controls against blue-stain and Wood- decay fungi (white- and brown-rot) was determined. Then, bioincised and untreated specimens were dipped or vacuum impregnated with six Wood Preservatives and substance uptake was assessed gravimetrically. Additionally, the penetration of 3-iodo-2-propynyl butylcarbamate (IPBC) into the Wood was analyzed by high-pressure liquid chromatography (HPLC). Finally, Wood resistance was assessed according to the European standards EN 152 and EN 113. Results showed no difference between bio- incised Wood without Preservatives and the untreated Wood against blue-stain discolouration. However, a significant (P < 0.05) increase in susceptibility against Wood decay was recorded. In the bioincised Wood samples a significantly higher uptake of all the different Preservatives was determined and the HPLC-method revealed that IPBC penetrated deeper into bioincised Wood than into control samples. The improved uptake of Preservatives into bioincised Wood resulted in a significantly higher resistance against white- and brown-rot fungi. However, only a slight protection against Wood discolouration by blue-stain fungi was recorded. The results of this study show for the first time that the biotechnological process with P. vitreus can be used to improve Wood durability by increasing the uptake and penetration of Wood Preservatives.
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permeability changes in heartWood of picea abies and abies alba induced by incubation with physisporinus vitreus
Holzforschung, 2006Co-Authors: Francis W. M. R. Schwarze, Helge Landmesser, Bruno Zgraggen, Markus HeebAbstract:The present study shows that isolates of P. vitreus have an extraordinary capacity to induce substantial permeability changes in heartWood of P. abies without causing significant losses in impact bending strength. The degradation of pit membranes by P. vitreus is an important aspect that could also have significant benefits in Wood protection processes. Further studies are currently in progress with the objective of optimising the uniformity of Wood colonisation and duration of incubation, so as to improve the permeability of water-borne Wood Preservatives or hydrophobic substances applied by brushing, dipping and impregnation.
Frederick Green - One of the best experts on this subject based on the ideXlab platform.
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the role of particle size of particulate nano zinc oxide Wood Preservatives on termite mortality and leach resistance
Nanoscale Research Letters, 2011Co-Authors: Carol A. Clausen, Rachel A Arango, Nami S Kartal, Frederick GreenAbstract:Historically most residential Wood Preservatives were aqueous soluble metal formulations, but recently metals ground to submicron size and dispersed in water to give particulate formulations have gained importance. In this study, the specific role nano-zinc oxide (ZnO) particle size and leach resistance plays in termite mortality resulting from exposure to particulate ZnO-treated Wood was investigated. Southern yellow pine (SYP) sapWood impregnated with three concentrations of two particle sizes (30 and 70 nm) of ZnO were compared to Wood treated with soluble zinc sulphate (ZnSO4) preservative for leach resistance and termite resistance. Less than four percent leached from the particulate nano-ZnO-treated specimens, while 13 to 25% of the zinc sulphate leached from the soluble treated Wood. Nano-ZnO was essentially non-leachable from Wood treated with 5% formulation for the 30-nm particle size. In a no-choice laboratory test, eastern subterranean termites (Reticulitermes flavipes) consumed less than 10% of the leached nano-ZnO-treated Wood with 93 to 100% mortality in all treatment concentrations. In contrast, termites consumed 10 to 12% of the leached ZnSO4-treated Wood, but with lower mortality: 29% in the 1% treatment group and less than 10% (5 and 8%, respectively) in the group of Wood blocks treated with 2.5 and 5.0% ZnSO4. We conclude that termites were repelled from consuming Wood treated with nano-ZnO, but when consumed it was more toxic to eastern subterranean termites than Wood treated with the soluble metal oxide formulation. There were no differences in leaching or termite mortality between the two particle sizes of nano-ZnO.
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natural durability of tropical and native Woods against termite damage by reticulitermes flavipes kollar
International Biodeterioration & Biodegradation, 2006Co-Authors: Rachel A Arango, Frederick Green, Patricia K Lebow, Kristina Hintz, Regis B MillerAbstract:Abstract Environmental pressure has resulted in voluntary removal of chromated copper arsenate (CCA) from Wood Preservatives in residential applications in the United States. A new generation of copper organic Preservatives was formulated as replacements, but these Preservatives may not provide a permanent solution to all related problems. Some of these issues include concern over copper in aquatic environments and corrosion of fasteners. Copper Preservatives in general are also poor inhibitors of mould. Therefore, we still need to evaluate alternative solutions in order to address current inadequacies of copper organic Wood Preservatives. In this study, six hardWoods and six softWoods were evaluated for their ability to resist termite damage by Reticulitermes flavipes. Mass loss versus specific gravity showed an inverse correlation in tropical hardWood species, but a slightly positive correlation in native softWood species. Also, southern yellow pine and Douglas-fir Wood blocks were evaluated after treatment with 0.1% copper borate, water-borne (WB) copper naphthanate, and N′N-naphthaloylhydroxylamine (NHA). Erisma, juniper, ipe, and white-cedar were highly resistant. The NHA-protected Douglas-fir and southern pine resisted attack as effectively as copper borate or WB copper naphthanate treatment. These results indicate that selected naturally durable Wood species, both tropical and native, inhibit R. flavipes damage as effectively as preservative treatment.
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Tolerance of Serpula lacrymans to copper-based Wood Preservatives
International Biodeterioration & Biodegradation, 2005Co-Authors: Anne Christine Steenkjær Hastrup, Carol A. Clausen, Frederick Green, Bo Boye Busk JensenAbstract:Serpula lacrymans, the dry rot fungus, is considered the most economically important Wood decay fungus in certain temperate regions of the world, namely northern Europe, Japan, and Australia. Previously, copper-based Wood Preservatives were commonly used for pressure treatment of Wood for building construction, but some decay fungi are known to be copper tolerant. In this study, soil-block tests were undertaken to clarify the effect of copper, copper citrate, and alkaline copper quaternary-type D (ACQ-D) on the decay capabilities of S. lacrymans compared with an alternative Wood preservative not containing copper. Twelve isolates of the dry rot fungus S. lacrymans and four other brown-rot species were evaluated for weight loss on Wood treated with 1.2% copper citrate, 0.5% ACQ-D, and 0.5% naphthaloylhydroxylamine (NHA). Eleven out of 12 isolates of S. lacrymans were shown to be tolerant towards copper citrate. The ACQ-D and NHA Preservatives, on the other hand, were both effective against the dry rot isolates.
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oxalic acid overproduction by copper tolerant brown rot basidiomycetes on southern yellow pine treated with copper based Preservatives
International Biodeterioration & Biodegradation, 2003Co-Authors: Carol A. Clausen, Frederick GreenAbstract:Accumulation of oxalic acid (OA) by brown-rot fungi and precipitation of copper oxalate crystals in Wood decayed by copper-tolerant decay fungi has implicated OA in the mechanism of copper tolerance. Understanding the role of OA in copper tolerance is important due to an increasing reliance on copper-based Wood Preservatives. In this study, four copper-tolerant brown-rot fungi were evaluated for decay capacity and OA production in early stages of exposure to four waterborne copper-based Wood Preservatives (ammonical copper quat type B and D, ammonical copper citrate, and chromated copper arsenate, type C) and one oilborne copper-based Wood preservative (oxine copper) in southern yellow pine blocks. Weight losses were less than 14% during the 4-week incubation. The presence of copper in waterborne Preservatives uniformly stimulated OA production by the test fungi within 2 weeks of exposure of the treated blocks to test fungi; 66% to 93% more OA was produced in treated blocks than untreated controls. Oxine copper, a nickel-containing oilborne preservative, prevented both weight loss and OA production in all fungi tested.
