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Matthias Noll - One of the best experts on this subject based on the ideXlab platform.
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material resistance of weathered wood plastic composites against Fungal Decay
International Biodeterioration & Biodegradation, 2012Co-Authors: Annette Naumann, Ina Stephan, Matthias NollAbstract:Abstract Material performance testing of wood-plastic composites (WPC) requires adequate and time-efficient evaluation of the resistance against Fungal colonisation and Decay. This study investigates the effects of weathering on WPCs and subsequent material degradation by fungi. Weathering using UV radiation, water spray and repeated frost incidents caused micro- and macro-cracks. Fourier transform infrared spectroscopy (FTIR) demonstrated delignification of wood particles at the weathered WPC surface. Despite of increased surface area, accessibility for Fungal hyphae and moisture content, weathering enhanced mass loss due to Fungal Decay only subtly but not significantly. These potentially enhancing effects for Fungal Decay are assumed to be outbalanced by delignification due to photo-oxidation and leaching of degradation products resulting in loss of nutrient sources essential for Fungal growth.
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material resistance of flame retarded wood plastic composites against fire and Fungal Decay
Polymer Degradation and Stability, 2012Co-Authors: Annette Naumann, Matthias Noll, Ina Stephan, Henrik Seefeldt, Ulrike BraunAbstract:Flame retarded wood-plastic composites (WPCs) should allow safe application in areas of fire risk. Halogen-free flame retardants can contain high amounts of nitrogen, phosphorus or sulphur, which may serve as nutrition source for wood degrading fungi and accelerate wood Decay. Therefore, the material resistance of WPCs with each of four flame retardants against both fire or Fungal Decay was examined in comparison to WPC without flame retardant. Expandable graphite showed the best performance against fire in cone calorimetry and radiant panel testing. Two ammonium polyphosphates and a third nitrogen-containing flame retardant were not as effective. Contrary to the possibility that flame retardants might enhance Fungal Decay of WPC, the opposite effect occurred in case of the wood-degrading fungi Trametes versicolor and Coniophora puteana according to determination of mass loss and decrease of bending modulus of elasticity. Only the surface mould Alternaria alternata slightly increased the degradation of WPCs with nitrogen-containing flame retardants compared to WPC without flame retardant according to mass loss data and FTIR-ATR analyses. Finally, WPC including expandable graphite as flame retardant was effective against both fire and Fungal Decay.
Christian Brischke - One of the best experts on this subject based on the ideXlab platform.
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Effect of size and shape of specimens on the mass loss caused by Coniophora puteana in wood durability tests
European Journal of Wood and Wood Products, 2020Co-Authors: Christian Brischke, Leopold K. Grünwald, Susanne BollmusAbstract:The experimental basis for testing the biological durability of wood often includes incubation experiments with wood-destroying basidiomycetes. Numerous parameters can affect the mass loss by Fungal Decay (ML_F) in laboratory durability tests and therefore being decisive for the resulting durability classification. Among others, the dimension of the wood specimen and the time of incubation impact on Fungal Decay. Hence, both parameters were examined within this study using 19 different specimen formats and four different incubation times. Specimens of larch heartwood ( Larix decidua Mill.) were incubated with pure cultures of the brown rot fungus Coniophora puteana . Scots pine sapwood ( Pinus sylvestris L.) was used as a reference. The wood specimens’ format turned out to significantly affect both mass loss by Fungal Decay (ML_F) and resulting x-values when ML_F of larch was compared with that of the reference Scots pine sapwood. Both measures were highest for specimen formats with moderate surface-volume ratios. ML_F and x-values depended on specimen size and shape as well as on the time of incubation. Reducing the specimen volume generally led to higher ML_F at a given incubation time, but prolonging incubation times led to higher x-values and thus to lower durability expressed as durability classes (DC). In summary, it appeared highly questionable that results of basidiomycete durability tests can be easily compared to each other when specimen format and/or incubation time deviate from the standard conditions.
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Wood-water relationships and their role for wood susceptibility to Fungal Decay
Applied Microbiology and Biotechnology, 2020Co-Authors: Christian Brischke, Gry AlfredsenAbstract:Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for Fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Wood is porous and hygroscopic; it can take up water in liquid and gaseous form, and water is released from wood through evaporation following a given water vapour pressure gradient. During the last decades, the perception of wood-water relationships changed significantly and so did the view on moisture-affected properties of wood. Among the latter is its susceptibility to Fungal Decay. This paper reviews findings related to wood-water relationships and their role for Fungal wood decomposition. These are complex interrelationships not yet fully understood, and current knowledge gaps are therefore identified. Studies with chemically and thermally modified wood are included as examples of Fungal wood substrates with altered moisture properties. Quantification and localization of capillary and cell wall water – especially in the over-hygroscopic range – is considered crucial for determining minimum moisture thresholds ( MMThr ) of wood-Decay fungi. The limitations of the various methods and experimental set-ups to investigate wood-water relationships and their role for Fungal Decay are manifold. Hence, combining techniques from wood science, mycology, biotechnology and advanced analytics is expected to provide new insights and eventually a breakthrough in understanding the intricate balance between Fungal Decay and wood-water relations. Key points • Susceptibility to wood-Decay fungi is closely linked to their physiological needs. • Content, state and distribution of moisture in wood are keys for Fungal activity. • Quantification and localization of capillary and cell wall water in wood is needed. • New methodological approaches are expected to provide new insights
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Wood-water relationships and their role for wood susceptibility to Fungal Decay.
Applied Microbiology and Biotechnology, 2020Co-Authors: Christian Brischke, Gry AlfredsenAbstract:Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for Fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Wood is porous and hygroscopic; it can take up water in liquid and gaseous form, and water is released from wood through evaporation following a given water vapour pressure gradient. During the last decades, the perception of wood-water relationships changed significantly and so did the view on moisture-affected properties of wood. Among the latter is its susceptibility to Fungal Decay. This paper reviews findings related to wood-water relationships and their role for Fungal wood decomposition. These are complex interrelationships not yet fully understood, and current knowledge gaps are therefore identified. Studies with chemically and thermally modified wood are included as examples of Fungal wood substrates with altered moisture properties. Quantification and localization of capillary and cell wall water – especially in the over-hygroscopic range – is considered crucial for determining minimum moisture thresholds (MMThr) of wood-Decay fungi. The limitations of the various methods and experimental set-ups to investigate wood-water relationships and their role for Fungal Decay are manifold. Hence, combining techniques from wood science, mycology, biotechnology and advanced analytics is expected to provide new insights and eventually a breakthrough in understanding the intricate balance between Fungal Decay and wood-water relations. • Susceptibility to wood-Decay fungi is closely linked to their physiological needs. • Content, state and distribution of moisture in wood are keys for Fungal activity. • Quantification and localization of capillary and cell wall water in wood is needed. • New methodological approaches are expected to provide new insights
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Changes in sorption and electrical properties of wood caused by Fungal Decay
Holzforschung, 2019Co-Authors: Christian Brischke, Simon Stricker, Linda Meyer-veltrup, Lukas EmmerichAbstract:As wet wood is prone to degradation by wood-destroying fungi, the monitoring of the moisture content (MC) of wood can be used to quantify the risk of Fungal infestation. Fungal Decay alters the sorption and electrical conductivity of wood, and thus the goal of the present study was to measure the electrical resistance (R) of wood after Fungal Decay as a function of MC. Scots pine sapwood (Pinus sylvestris L.) and European beech wood (Fagus sylvatica L.) were submitted to Decay by Coniophora puteana (a brown rot fungus, BR) and Trametes versicolor (a white rot fungus, WR) and the mass loss (ML) due to the Fungal metabolism was measured. The sorption isotherms were determined by dynamic vapor sorption (DVS), and comparative gravimetric- and R-based MC measurements were conducted. BR and WR reduced the sorption of wood and lowered its R in the hygroscopic range, where the Decay led to an overestimation of wood MC, while wood MC was dramatically underestimated above fiber saturation (FS). Specimens showed an MC well above FS if measured directly after harvesting and an increased R compared to unDecayed wood at a given MC. BR-Decayed specimens were dried and rewetted, and such specimens showed an elevated R beyond FS. In the case of WR-Decayed wood, the R was reduced at a given MC.
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critical moisture conditions for Fungal Decay of modified wood by basidiomycetes as detected by pile tests
Holzforschung, 2016Co-Authors: Linda Meyer, Christian Brischke, Andreas Treu, Pia LarssonbrelidAbstract:The aim of cell wall modification is to keep wood moisture content (MC) below favorable conditions for Decay organisms. However, thermally modified, furfurylated, and acetylated woods partly show higher MCs than untreated wood in outdoor exposure. The open question is to which extent Decay is influenced by the presence of liquid water in cell lumens. The present paper contributes to this topic and reports on physiological threshold values for wood Decay fungi with respect to modified wood. In total, 4200 specimens made from acetylated, furfurylated, and thermally modified beech wood (Fagus sylvatica L.) and Scots pine sapwood (sW) (Pinus sylvestris L.) were exposed to Coniophora puteana and Trametes versicolor. Piles consisting of 50 small specimens were incubated above malt agar in Erlenmeyer flasks for 16 weeks. In general, pile upward mass loss (ML) and MC decreased. Threshold values for Fungal growth and Decay (ML≥2%) were determined. In summary, the minimum MC for Fungal Decay was slightly below fiber saturation point of the majority of the untreated and differently modified materials. Surprisingly, T. versicolor was able to degrade untreated beech wood at a minimum of 15% MC, and growth was possible at 13% MC. By contrast, untreated pine sW was not Decayed by C. puteana at less than 29% MC. © 2016 by De Gruyter 2016.
Jody Jellison - One of the best experts on this subject based on the ideXlab platform.
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Effects of hot water extraction and Fungal Decay on wood crystalline cellulose structure
Cellulose, 2011Co-Authors: Caitlin Howell, Barry Goodell, Anne Christine Steenkjær Hastrup, Rory Jara, Flemming Hofmann Larsen, Jody JellisonAbstract:The effect of hot-water extraction and two types of Fungal Decay, brown rot and white rot, on wood crystalline cellulose structure was examined using a combination of X-ray diffraction (XRD) and ^13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Although having opposite effects on the overall crystallinity of the wood, the XRD results revealed that both extraction and brown-rot Decay caused a significant decrease in the 200 crystal plane spacing ( d -spacing) not seen for the white-rotted samples. This effect was found to be additive, as samples that were first extracted, then Decayed showed a double decrease in d -spacing compared to that caused by extraction alone. This suggested that, despite having a similarly directed effect on the spacing of the crystalline planes, the two treatment methods facilitate a decrease in d -spacing in different ways. NMR results support the conclusion of differing structural effects, suggesting that the hot-water extraction procedure was causing a co-crystallization of existing crystalline domains, while the brown rot Decay was depolymerizing the cellulose chains of the crystals, possibly allowing the remaining crystalline material the freedom to relax into a more energetically favorable, tightly packed state. These findings could have important implications for those seeking to understand the effects of modification treatments or biodegradation of crystalline cellulose nanostructures in their native states.
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Fungal Decay of Wood : Soft Rot-Brown Rot-White Rot
2008Co-Authors: Barry Goodell, Yuhui Qian, Jody JellisonAbstract:Wood Decay by fungi is typically classified into three types: soft rot, brown rot and white rot. Brown rot fungi are the most prevalent with regard to attack on coniferous, structural wood products in North America. The wood Decayed by brown rot fungi is typically brown and crumbly and it is degraded via both non-enzymatic and enzymatic systems. A series of celluloytic enzymes are employed in the degradation process by brown rot fungi, but no lignin degrading enzymes are typically involved. White rot fungi are typically associated with hardwood Decay and their wood Decay patterns can take on different forms. White rotted wood normally has a bleached appearance and this may either occur uniformly, leaving the wood a spongy or stringy mass, or it may appear as a selective Decay or a pocket rot. White rot fungi possess both cellulolytic and lignin degrading enzymes and these fungi therefore have the potential to degrade the entirety of the wood structure under the correct environmental conditions. Soft rot fungi typically attack higher moisture, and lower lignin content wood and can create unique cavities in the wood cell wall. Less is known about the soft rot degradative enzyme systems, but their degradative mechanisms are reviewed along with the degradative enzymatic and non-enzymatic systems known to exist in the brown rot and white rot fungi. As we learn more about the non-enzymatic systems involved in both brown and white rot degradative systems, it changes our perspective on the role of enzymes in the Decay process. This in turn is affecting the way we think about controlling Decay in wood preservation and wood protection schemes, as well as how we may apply Fungal Decay mechanisms in bioindustrial processes.
Gry Alfredsen - One of the best experts on this subject based on the ideXlab platform.
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Wood-water relationships and their role for wood susceptibility to Fungal Decay
Applied Microbiology and Biotechnology, 2020Co-Authors: Christian Brischke, Gry AlfredsenAbstract:Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for Fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Wood is porous and hygroscopic; it can take up water in liquid and gaseous form, and water is released from wood through evaporation following a given water vapour pressure gradient. During the last decades, the perception of wood-water relationships changed significantly and so did the view on moisture-affected properties of wood. Among the latter is its susceptibility to Fungal Decay. This paper reviews findings related to wood-water relationships and their role for Fungal wood decomposition. These are complex interrelationships not yet fully understood, and current knowledge gaps are therefore identified. Studies with chemically and thermally modified wood are included as examples of Fungal wood substrates with altered moisture properties. Quantification and localization of capillary and cell wall water – especially in the over-hygroscopic range – is considered crucial for determining minimum moisture thresholds ( MMThr ) of wood-Decay fungi. The limitations of the various methods and experimental set-ups to investigate wood-water relationships and their role for Fungal Decay are manifold. Hence, combining techniques from wood science, mycology, biotechnology and advanced analytics is expected to provide new insights and eventually a breakthrough in understanding the intricate balance between Fungal Decay and wood-water relations. Key points • Susceptibility to wood-Decay fungi is closely linked to their physiological needs. • Content, state and distribution of moisture in wood are keys for Fungal activity. • Quantification and localization of capillary and cell wall water in wood is needed. • New methodological approaches are expected to provide new insights
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Wood-water relationships and their role for wood susceptibility to Fungal Decay.
Applied Microbiology and Biotechnology, 2020Co-Authors: Christian Brischke, Gry AlfredsenAbstract:Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for Fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Wood is porous and hygroscopic; it can take up water in liquid and gaseous form, and water is released from wood through evaporation following a given water vapour pressure gradient. During the last decades, the perception of wood-water relationships changed significantly and so did the view on moisture-affected properties of wood. Among the latter is its susceptibility to Fungal Decay. This paper reviews findings related to wood-water relationships and their role for Fungal wood decomposition. These are complex interrelationships not yet fully understood, and current knowledge gaps are therefore identified. Studies with chemically and thermally modified wood are included as examples of Fungal wood substrates with altered moisture properties. Quantification and localization of capillary and cell wall water – especially in the over-hygroscopic range – is considered crucial for determining minimum moisture thresholds (MMThr) of wood-Decay fungi. The limitations of the various methods and experimental set-ups to investigate wood-water relationships and their role for Fungal Decay are manifold. Hence, combining techniques from wood science, mycology, biotechnology and advanced analytics is expected to provide new insights and eventually a breakthrough in understanding the intricate balance between Fungal Decay and wood-water relations. • Susceptibility to wood-Decay fungi is closely linked to their physiological needs. • Content, state and distribution of moisture in wood are keys for Fungal activity. • Quantification and localization of capillary and cell wall water in wood is needed. • New methodological approaches are expected to provide new insights
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Decay of wooden commodities – Moisture risk analysis, service life prediction and performance assessment in the field
Wood Material Science & Engineering, 2014Co-Authors: Thomas Bornemann, Christian Brischke, Gry AlfredsenAbstract:AbstractOne key issue in wood construction is durability. Constant wetting and suitable temperatures for Fungal growth promote the risk of Decay and thus a decrease in structural stability and performance. Hence, performance-based prediction models seem to be reasonable to predict the in-service performance of wooden structures in different outdoor exposure situations. Within this study continuous wood moisture content (MC) and temperature measurements were conducted on five different test objects. Four test set-ups were installed at a test site in Hannover, Germany. A fifth set-up was exposed in As, Norway. Data-sets were applied to a dose–response performance model considering wood MC and temperature as key factors for Fungal Decay. The expected service life (SL) was calculated for different materials and constructions. In addition, the depth and distribution of Decay was assessed using a pick test and compared with the calculated SL. Differences regarding the risk of Fungal Decay for various constructi...
Annette Naumann - One of the best experts on this subject based on the ideXlab platform.
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material resistance of weathered wood plastic composites against Fungal Decay
International Biodeterioration & Biodegradation, 2012Co-Authors: Annette Naumann, Ina Stephan, Matthias NollAbstract:Abstract Material performance testing of wood-plastic composites (WPC) requires adequate and time-efficient evaluation of the resistance against Fungal colonisation and Decay. This study investigates the effects of weathering on WPCs and subsequent material degradation by fungi. Weathering using UV radiation, water spray and repeated frost incidents caused micro- and macro-cracks. Fourier transform infrared spectroscopy (FTIR) demonstrated delignification of wood particles at the weathered WPC surface. Despite of increased surface area, accessibility for Fungal hyphae and moisture content, weathering enhanced mass loss due to Fungal Decay only subtly but not significantly. These potentially enhancing effects for Fungal Decay are assumed to be outbalanced by delignification due to photo-oxidation and leaching of degradation products resulting in loss of nutrient sources essential for Fungal growth.
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material resistance of flame retarded wood plastic composites against fire and Fungal Decay
Polymer Degradation and Stability, 2012Co-Authors: Annette Naumann, Matthias Noll, Ina Stephan, Henrik Seefeldt, Ulrike BraunAbstract:Flame retarded wood-plastic composites (WPCs) should allow safe application in areas of fire risk. Halogen-free flame retardants can contain high amounts of nitrogen, phosphorus or sulphur, which may serve as nutrition source for wood degrading fungi and accelerate wood Decay. Therefore, the material resistance of WPCs with each of four flame retardants against both fire or Fungal Decay was examined in comparison to WPC without flame retardant. Expandable graphite showed the best performance against fire in cone calorimetry and radiant panel testing. Two ammonium polyphosphates and a third nitrogen-containing flame retardant were not as effective. Contrary to the possibility that flame retardants might enhance Fungal Decay of WPC, the opposite effect occurred in case of the wood-degrading fungi Trametes versicolor and Coniophora puteana according to determination of mass loss and decrease of bending modulus of elasticity. Only the surface mould Alternaria alternata slightly increased the degradation of WPCs with nitrogen-containing flame retardants compared to WPC without flame retardant according to mass loss data and FTIR-ATR analyses. Finally, WPC including expandable graphite as flame retardant was effective against both fire and Fungal Decay.
