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Christian Brischke - One of the best experts on this subject based on the ideXlab platform.
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combined effect of Wood Moisture content drill bit rotational speed and feed rate on drilling resistance measurements in norway spruce picea abies l karst
Wood Material Science and Engineering, 2020Co-Authors: Evgenii Sharapov, Holger Militz, Christian Brischke, Elena SmirnovaAbstract:An IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the combined effect of Wood Moisture content (MC), drill bit rotational speed...
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prediction of modulus of elasticity in static bending and density of Wood at different Moisture contents and feed rates by drilling resistance measurements
European Journal of Wood and Wood Products, 2019Co-Authors: Holger Militz, Evgenii Sharapov, Christian Brischke, Elena SmirnovaAbstract:An IML-RESI PD 400 drilling tool and a standard spade drill bit were used to find the correlations of drilling and feeding resistance with the modulus of elasticity in static bending and density of Wood. In total, 1575 drillings at 0.5, 1.0 and 1.5 m/min feed rates were made in specimens of Scots pine (Pinus sylvestris L.), European beech (Fagus sylvatica L.), English oak (Quercus robur L.) and common lime (Tilia europaea L.), which were oven-dried, conditioned at 20 °C/65% RH and 20 °C/95% RH and vacuum-impregnated with water. The feed rate (feed rate per major cutting edge or uncut chip thickness) had a significant impact on the prediction of density and modulus of elasticity through drilling resistance measurements and should be considered for comparison of properties and internal conditions of Wood. Because of stronger correlation between drilling resistance and tested Wood properties compared to feeding resistance, drilling resistance is recommended for density and MOE prediction of sound Wood. Moisture content had no significant impact on the modulus of elasticity prediction by the drilling resistance measurements, while density can be predicted by linear models for two stages of Moisture content variation, below and above fibre saturation.
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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, Andreas Treu, Christian Brischke, 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.
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resistance based Moisture content measurements on native modified and preservative treated Wood
European Journal of Wood and Wood Products, 2014Co-Authors: Christian Brischke, Stefan Clemens LampenAbstract:Resistance characteristics were determined for a total of 27 Wood-based materials containing native soft- and hardWoods, differently modified timbers and preservative treated timbers. A functional relation between measured electrical resistance and gravimetrical Wood Moisture content (MC) was established in a range between 15 and 50 % MC. Most precise MC estimation was found for salt-treated timber (±2.5 %), followed by native timber (±3.5 %) and modified timber (±7 %) in the hygroscopic range. As expected, preciseness decreased above fiber saturation, but was still sufficient for native timber (±8 %) and preservative treated Wood (±5 %) at approx. 50 % MC.
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dose response relationships between Wood Moisture content Wood temperature and fungal decay determined for 23 european field test sites
Wood Science and Technology, 2008Co-Authors: Christian Brischke, Andreas Otto RappAbstract:Scots pine sapWood (Pinus sylvestris L.) and Douglas fir heartWood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at 23 different European test sites under different exposure conditions (in total 27 test sets). The material climate in terms of Wood Moisture content (MC) and Wood temperature was automatically monitored over a period of up to 7 years and compared with the progress of decay. The overall aim of this study was to establish dose–response relationships between climate factors and decay as a basis for the service life prediction of Wood. The “Scheffer Climate Index” based on weather data collected at official meteorological stations at the different test sites poorly correlated with the corresponding decay progress and was therefore not a suitable tool for estimating site-specific decay potential. In contrast, the use of the combined material climatic parameters MC and Wood temperature led to a feasible dose–response function and turned out to be a useful basis for service life prediction of Wood.
Andreas Otto Rapp - One of the best experts on this subject based on the ideXlab platform.
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influence of Wood Moisture content and Wood temperature on fungal decay in the field observations in different micro climates
Wood Science and Technology, 2008Co-Authors: Christian Brischke, Andreas Otto RappAbstract:In this study, Scots pine sapWood (Pinus sylvestris L.) and Douglas fir heartWood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at four different exposure sites and under different exposure conditions (in total ten test sets). The material climate of Wood in terms of Wood Moisture content (MC) and Wood temperature was automatically monitored over a period of 6 years and compared with the progress of decay. The aim of this study was to highlight the interrelationship between microclimate, material climate, and decay as a basis for the establishment of dose-response functions to be used for service life prediction of Wood and Wood-based products. Differences in resulting decay dynamics between the test sites as well as between the different types of exposure were quantified and discussed with respect to corresponding microclimatic and material climatic conditions. The time between the beginning of exposure and the first occurrence of visible decay varied between the sites and influenced the total decay development. The fundamental importance of direct decay factors, such as MC and Wood temperature, were underlined and basic requirements for establishing dose-response-functions to be used in service life prediction models were derived.
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dose response relationships between Wood Moisture content Wood temperature and fungal decay determined for 23 european field test sites
Wood Science and Technology, 2008Co-Authors: Christian Brischke, Andreas Otto RappAbstract:Scots pine sapWood (Pinus sylvestris L.) and Douglas fir heartWood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at 23 different European test sites under different exposure conditions (in total 27 test sets). The material climate in terms of Wood Moisture content (MC) and Wood temperature was automatically monitored over a period of up to 7 years and compared with the progress of decay. The overall aim of this study was to establish dose–response relationships between climate factors and decay as a basis for the service life prediction of Wood. The “Scheffer Climate Index” based on weather data collected at official meteorological stations at the different test sites poorly correlated with the corresponding decay progress and was therefore not a suitable tool for estimating site-specific decay potential. In contrast, the use of the combined material climatic parameters MC and Wood temperature led to a feasible dose–response function and turned out to be a useful basis for service life prediction of Wood.
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decay influencing factors a basis for service life prediction of Wood and Wood based products
Wood Material Science and Engineering, 2006Co-Authors: Christian Brischke, Rolf Bayerbach, Andreas Otto RappAbstract:Abstract The need for a reliable database and a corresponding methodology to predict service life of Wood and Wood-based products emanates from the European Construction Products Directive, as well as from a strong interest by the building industry. A literature review on decay-influencing factors and on previous approaches to implement methods and tools for service life estimations was the basis for a concept for service life prediction of Wooden components. The effect of various indirect decay factors was found to be reducible to a few direct decay factors, with material resistance, as well as Wood Moisture content, Wood temperature and their dynamics among the key factors for fungal decay. Approaches that consider only indirect factors, e.g. climate indices, suffer from poor correlation with service life or decay rates. Therefore, the overall consideration of all possible influences, reduced on the key direct decay factors in first instance, is recommended. To fill a theoretical model with a reliable d...
Yoshio Otani - One of the best experts on this subject based on the ideXlab platform.
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effects of Moisture content and burning period on concentration of smoke particles and particle bound polycyclic aromatic hydrocarbons from rubber Wood combustion
Aerosol and Air Quality Research, 2009Co-Authors: Jiraporn Chomanee, Surajit Tekasakul, Perapong Tekasakul, Masami Furuuchi, Yoshio OtaniAbstract:Physical and chemical characteristics of particles from rubber-Wood combustion in a natural rubber sheet smoking process were studied. Experimental parameters include Wood Moisture content and Wood-burning period. The size distribution of smoke particles was measured by using an 8-stage Andersen air sampler. Total smoke particle concentration was determined by collecting particles using a modified high volume sampler. Polycyclic Aromatic Hydrocarbons (PAHs) were extracted with Benzene-Ethanol by using ultrasonic technique and analyzed by HPLC/UV detection. Results show that the size distribution of smoke particles is single-mode in which the mass median aerodynamic diameter (MMAD) is 0.68 μm and the average smoke concentration is 15.806 mg/m^3. This is equivalent to a mass emission to workplace of 4.33 kg/month/room. The smoke particle concentration and associated PAH concentration clearly depend on the Wood Moisture content and burning period. The highest PAH concentration and smoke particle concentrations were found to be 60.59 to 118.06 μg/m^3 and 23.35 to 47.54 mg/m^3, respectively, for a Wood Moisture content of 37.4 to 73.6% d.b. (dry basis) at the initial period. Smoke particle-bound PAHs are dominated by 4-6 ring PAH compounds that contribute to more than 60% of the total PAHs.
Holger Militz - One of the best experts on this subject based on the ideXlab platform.
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combined effect of Wood Moisture content drill bit rotational speed and feed rate on drilling resistance measurements in norway spruce picea abies l karst
Wood Material Science and Engineering, 2020Co-Authors: Evgenii Sharapov, Holger Militz, Christian Brischke, Elena SmirnovaAbstract:An IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the combined effect of Wood Moisture content (MC), drill bit rotational speed...
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prediction of modulus of elasticity in static bending and density of Wood at different Moisture contents and feed rates by drilling resistance measurements
European Journal of Wood and Wood Products, 2019Co-Authors: Holger Militz, Evgenii Sharapov, Christian Brischke, Elena SmirnovaAbstract:An IML-RESI PD 400 drilling tool and a standard spade drill bit were used to find the correlations of drilling and feeding resistance with the modulus of elasticity in static bending and density of Wood. In total, 1575 drillings at 0.5, 1.0 and 1.5 m/min feed rates were made in specimens of Scots pine (Pinus sylvestris L.), European beech (Fagus sylvatica L.), English oak (Quercus robur L.) and common lime (Tilia europaea L.), which were oven-dried, conditioned at 20 °C/65% RH and 20 °C/95% RH and vacuum-impregnated with water. The feed rate (feed rate per major cutting edge or uncut chip thickness) had a significant impact on the prediction of density and modulus of elasticity through drilling resistance measurements and should be considered for comparison of properties and internal conditions of Wood. Because of stronger correlation between drilling resistance and tested Wood properties compared to feeding resistance, drilling resistance is recommended for density and MOE prediction of sound Wood. Moisture content had no significant impact on the modulus of elasticity prediction by the drilling resistance measurements, while density can be predicted by linear models for two stages of Moisture content variation, below and above fibre saturation.
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effect of open assembly time and equilibrium Moisture content on the penetration of polyurethane adhesive into thermally modified Wood
Journal of Adhesion, 2017Co-Authors: Alireza Bastani, Stergios Adamopoulos, Holger MilitzAbstract:ABSTRACTThe effect of Wood Moisture content and open assembly time on penetration of polyurethane (PU) adhesive into thermally treated Scots pine (195 and 210°C) was investigated according to effective penetration (EP) and maximum penetration (MP) measurements using fluorescence microscopy. For samples treated at 195°C, a higher EP was noted at 8.6% equilibrium Moisture content (EMC) after both assembly times (15 and 30 min) while for samples treated at 210°C, increasing Wood Moisture content resulted in a significant decrease in EP at 12.5% EMC after 15 min assembly time. Extending open assembly time was found to increase the EP of PU adhesive only in the case of samples treated at 195°C and with 8.6% EMC. For samples treated at both treatment temperatures and after shorter open assembly time, the highest MP was observed at moderate EMC levels of 8.6 and 8.2% and the lowest at the higher EMC levels of 13.2 and 12.5%.
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Wood Moisture content during the thermal modification process affects the improvement in hygroscopicity of scots pine sapWood
Wood Science and Technology, 2016Co-Authors: Michael Altgen, Tamais Hofmann, Holger MilitzAbstract:Elevated Wood Moisture contents during the thermal modification process have been shown to adversely affect the improvement in dimensional stability and hygroscopicity. This study tested the hypothesis that the effect of elevated Wood Moisture content is based on the impact of water on chemical reactions which determine the cell wall matrix stiffness. Samples of Scots pine sapWood (Pinus sylvestris L.) were thermally modified in saturated water vapor at different peak temperatures and durations starting either in oven-dry or in water-saturated state. For a given mass loss caused by the modification process, the improvement in maximum swelling and equilibrium Moisture content was stronger for oven-dry samples. After removal of water-soluble degradation products, which caused a cell wall bulking effect, the maximum swelling even increased after modification in water-saturated state. Based on dynamic vapor sorption measurements, it was evidenced that the modification in oven-dry state increased the cell wall matrix stiffness which improved dimensional stability and hygroscopicity. Enhanced bond formation in the polymeric network, i.e., via condensation and cross-linking reactions during the treatment of oven-dry Wood, is suggested as a cause for this increase in matrix stiffness. In contrast, the modification in water-saturated state enhanced the flexibility of the cell wall matrix, which increased the cell wall swelling and limited the improvement of hygroscopicity to the reduction in OH groups by removal of hemicelluloses. This enhanced matrix flexibility was potentially caused by predominant hydrolytic cleavage of bonds in case of water-saturated samples, evident from the chemical analysis of soluble degradation products, which increased the free volume between adjacent matrix polymers.
Steffen Rust - One of the best experts on this subject based on the ideXlab platform.
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electric resistivity tomography shows radial variation of electrolytes in quercus robur
Canadian Journal of Forest Research, 2010Co-Authors: Dirk Bieker, Steffen RustAbstract:Electric resistivity tomograms of English oak (Quercus robur L.) show a very distinct pattern of electric resistivity that has not been found in any other tree species yet and that cannot be related to the distribution of Wood Moisture content over the stem cross section. To reveal the factors underlying this two-dimensional pattern of electric resistivity, the variation of specific gravity and Wood Moisture content was analyzed in 18 cross sections of six roadside English oak trees after electric resistivity tomography. pH and electrolyte content were analyzed in two representative cross sections. Results show that electric resistivity correlates neither with Wood Moisture content nor density. The steep increase in electric resistivity at the sapWood–heartWood boundary correlates well with decreasing pH, potassium, and magnesium. The decreasing electric resistivity within the heartWood of English oak correlates with potassium and magnesium, increasing from the sapWood–heartWood boundary to the pith. More...
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non destructive monitoring of early stages of white rot by trametes versicolor in fraxinus excelsior
Annals of Forest Science, 2010Co-Authors: Dirk Bieker, Rolf Kehr, Gesine Weber, Steffen RustAbstract:Keywords: development / ERT / monitoring / tomography / Wood fungal decay Abstract • Non-destructive detection of fungal decay in living trees is relevant for forest management of valu- able species, hazard tree assessment, and research in forest pathology. A variety of tomographic methods, based on stress wave timing, radioactive radiation, or electrical resistivity have been used to detect decay in standing trees non-destructively. But apart from mobile gamma ray computed tomog- raphy (Habermehl and Ridder, 1993) which is virtually unavailable, the detection of incipient stages of decay is still not possible. • Wood Moisture and electrolyte content influence the electric resistivity of Wood. Both are changed by fungal decay. Therefore electric resistivity tomography (ERT) should detect decay in its early stages. Then it could be used to monitor the spatial and temporal progress of degradation. • We infected four Fraxinus excelsior trees with Trametes versicolor using Wooden dowels and mea- sured two-dimensional electric resistivity tomograms 3, 10, 13 and 21 months after infection. Imme- diately after the last electric resistivity measurement trees were felled for further analyses of stem cross-sections. Wood Moisture content and raw density had significantly increased in infected areas, but dry density had not significantly changed after 21 months. Areas of very low electric resistiv- ity around the infected wounds correlated very well with infected Wood in the stem cross-sections. Increasing areas of low electric resistivity around the infected wounds during consecutive measure- ments indicate increasing areas of infected Wood. • We conclude that the growth of white rot by Trametes versicolor can be monitored with electric resistivity tomography (ERT) beginning from incipient stages, even before Wood density decreases. ERT could therefore be a powerful research tool for decay dynamics as well as a method for diagnos- ing Wood decay in forestry and arboriculture.
