Eberswalde University Of Applied Sciences

Eberswalde, Germany
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Stork M.,University of Heidelberg | Schulte A.,Free University of Berlin | Murach D.,Eberswalde University Of Applied Sciences
Biomass and Bioenergy | Year: 2014

Woody biomass (dendromass) today already has an important role in bioenergy production and will even increase in the future as a renewable resource for energetic as well as for material use. In eastern Germany, an increasing demand for dendromass in renewable energy production is unlikely to be covered by sustainable forest wood production. Hence, a deficit for the federal state of Brandenburg of 4.02 million tonnes per year is predicted. Besides imports, one option of increasing dendromass supply in Brandenburg is short rotation coppice (SRC) on arable land. The potential of SRC on arable land is determined by the economic competitiveness of SRC compared to conventional annual crops. This factor is strongly influenced by the water supply, expressed as the transpiration water supply (TWS) in the growing season, and the soil quality. First evaluations of SRC potentials in Brandenburg identify large areas of arable land where SRC seems to be able to compete with annual crops. Potential areas in the Dahme river catchment, located in the south of Berlin, were identified at a regional scale through a GIS-based approach. The results indicate that lowland river catchments like the Dahme basin have great potentials for fuelwood production. Especially the large amount of arable land with accessible groundwater resources offers water for transpiration in a region where average annual precipitation and water storage capacity of soils is relatively low (550mm and 100-150mmm-1 resp.) and thus too small to meet the demands of optimal SRC growth. In total, 340,000 tonnes fuelwood could be produced annually in the Dahme river catchment, if all potential sites were transformed into SRC. This accounts for 8.5% of the deficit produced on just 1.8% of the federal state of Brandenburg's total agricultural area by 2030 and meet the heating energy demand of approximately 130,000 people. The results show that the applied method is an effective way to identify biomass potentials in mesoscale river basins and demonstrates the relevance of the Dahme catchment for a sustainable energy supply in the future. © 2014 Elsevier Ltd.

Lawes M.J.,Charles Darwin University | Richards A.,CSIRO | Dathe J.,Eberswalde University Of Applied Sciences | Midgley J.J.,University of Cape Town
Plant Ecology | Year: 2011

We investigated the fire resistance conferred by bark of seven common tree species in north Australian tropical savannas. We estimated bark thermal conductance and examined the relative importance of bark thickness, density and moisture content for protecting the cambium from lethal fire temperatures. Eucalypt and non-eucalypt species were contrasted, including the fire-sensitive conifer Callitris intratropica. Cambial temperature responses to bark surface heating were measured using a modified wick-fire technique, which simulated a heat pulse comparable to surface fires of moderate intensity. Bark thickness was a better predictor of resistance to cambial injury from fires than either bark moisture or density, accounting for 68% of the deviance in maximum temperature of the cambium. The duration of heating required to kill the cambium of a tree (τ c) was directly proportional to bark thickness squared. Although species did not differ significantly in their bark thermal conductance (k), the thinner barked eucalypts nevertheless achieved similar or only slightly lower levels of fire resistance than much thicker barked non-eucalypts. Bark thickness alone cannot account for the latter and we suggest that lower bark moisture content among the eucalypts also contributes to their apparent fire resistance. Unique eucalypt meristem anatomy and epicormic structures, combined with their bark traits, probably facilitate resprouting after fire and ensure the dominance of eucalypts in fire-prone savannas. This study emphasises the need to take into account both the thermal properties of bark and the mechanism of bud protection in characterising the resprouting ability of savanna trees. © 2011 Springer Science+Business Media B.V.

Klausler O.,ETH Zurich | Clauss S.,ETH Zurich | Lubke L.,Eberswalde University Of Applied Sciences | Trachsel J.,ETH Zurich | Niemz P.,ETH Zurich
International Journal of Adhesion and Adhesives | Year: 2013

Tensile strength, Young's modulus and stress-strain behaviour of adhesive films were investigated by means of tensile tests at 23 °C under various ambient moisture conditions (5-95% RH, water exposure and redrying). The adhesive films were produced from two one-component moisture-curing polyurethane adhesives (1C PUR), one phenol-resorcinol-formaldehyde resin (PRF) and one melamine-urea-formaldehyde resin (MUF). These four adhesive films are commonly used for structural bonding of wood. In addition, films were made from three non-commercial 1C PUR prepolymers, all of which had their ethylene oxide (EO) proportions specifically modified. For all the tested adhesives other than PRF, the findings of the tensile tests revealed a linear dependency of tensile strength and Young's modulus on the relative humidity (RH). Both parameters decreased significantly with increasing RH. The redried samples illustrate the reversibility of this effect. These observations are mainly attributed to physical bonds like hydrogen bonds, which are disrupted by water molecules entering the polymer film and re-established whilst re-drying. No evidence was found for an influence of the EO content of the prepolymers on their tensile strength or Young's modulus at high RH. Regarding the 1C PURs at high RH the findings revealed an influence of hydrophilic catalyst on tensile strength, but not on Young's modulus. Under all tested ambient conditions, the fracture strain of PRF and MUF specimens remained below 5%, whereas that of the 1C PURs and the prepolymers reached at least 20%. This illustrates the ductility of the tested 1C PUR polymers on all tested climate stages in contrast to the brittleness of MUF and PRF polymers. © 2013 Elsevier Ltd.

Pfriem A.,Eberswalde University Of Applied Sciences
Drvna Industrija | Year: 2015

The unique mechanical and acoustical properties of wood and its aesthetic appeal still make it the material of choice for musical instruments. Here tropical hardwoods are typically used in musical instruments. This paper gives an overview of how the use of thermally modified wood can contribute to the use of raw materials for musical instruments. It is shown that a mild thermal treatment leads to clear changes of the measurable acoustic characteristics, such as Young’s modulus, damping and sound velocity. In conclusion, thermally modified wood (mild treatment) is a material with favorable characteristics for making musical instruments. © 2015, Journal Drvna Industrija. All rights reserved.

The aim of the investigations was to evaluate the influence of a thermal modification on the water absorption behaviour of spruce (Picea abies (L.) Karst.). After recording the water uptake of wood samples by partial immersion, a water absorption coefficient of the material could be determined according to EN ISO 15148:2002. The thermal modification results in an alteration of the water absorption behaviour in dependence on the sectional area. In radial and tangential direction the water absorption decreases with the modification. In contrast, in longitudinal direction the water uptake increases.

Herold N.,Eberswalde University Of Applied Sciences | Pfriem A.,Eberswalde University Of Applied Sciences
European Journal of Wood and Wood Products | Year: 2013

Due tomechanical restrictions veneer application on surfaces is limited to simple shapes. To enhance the moulding performance veneer samples were impregnated with furfuryl alcohol for improved plasticization. The plasticizing effect of furfuryl alcohol was determined according to the Erichsen cupping test and results were compared to control samples and water saturated samples. The extent of furfuryl alcohol plasticization is comparable to the use of water with the shaping path being distinctly improved by 71 % for water and 86 % for furfuryl alcohol. Little changes were observed for maximum load. © Springer-Verlag Berlin Heidelberg 2013.

Pfriem A.,Eberswalde University Of Applied Sciences | Dietrich T.,TU Dresden | Buchelt B.,TU Dresden
Holzforschung | Year: 2012

The densification of wood leads to better mechanical properties, e.g., an increased hardness and dimensional stability. However, densified or shaped wood in contact with water springs back into its original shape without fixation. Hence, the aim of this study was the development of a combined densification and fixation procedure. Beech wood samples (Fagus sylvatica L.) were impregnated with a solution consisting of furfuryl alcohol and maleic anhydride. The compression of these impregnated samples to approximately 30 followed by a curing process in a heating press resulted in a significant increase of hardness and dimensional stability. The spring-back-effect was clearly reduced by the in situ polymerization of the furfuryl alcohol solution to furan resins. © 2012 by Walter de Gruyter Berlin Boston 2012.

Richards A.E.,CSIRO | Dathe J.,Eberswalde University Of Applied Sciences | Cook G.D.,CSIRO
Soil Biology and Biochemistry | Year: 2012

Soil respiration (R s) is the second-largest source of CO 2 to the atmosphere in terrestrial systems. In tropical savannas seasonal moisture availability and frequent fires drive ecosystem dynamics and may have a considerable impact on soil carbon (C) cycling, including R s. In order to test the effect of fire on soil C cycling we measured R s in annually burnt and unburnt plots in wet and dry seasons at a long-term fire experiment established in savanna woodlands of northern Australia. There was a significant interaction between season and fire, with highest rates of daily R s (722 mmol CO 2 m -2 d -1) observed in the wet season on unburnt, leaf litter patches. The three fold higher R s rate on unburnt plots in the wet season was due to greater root-derived respiration (R root: 356 mmol CO 2 m -2 d -1), while smaller changes to soil-derived respiration (R soil: 51 mmol CO 2 m -2 d -1) were simply the result of C moving through decomposition rather than combustion pathways. Relationships between instantaneous R s and soil temperature showed hysteresis with variable direction, suggesting that season and fire treatment also influence the soil depth at which CO 2 is produced. We suggest that (1) changes to fire regimes, through active management or climate change, in tropical savannas could have an impact on R s, and (2) the direct effect of fire on soil C cycling is limited to the removal of aboveground litter inputs. © 2012.

Schneeweiss J.,University of Gottingen | Schatz T.,Eberswalde University Of Applied Sciences
Quaternary International | Year: 2014

The Höhbeck, an insular elevation in the middle of the vast Elbe River floodplain, was a strategically important place in the Early and High Middle Ages. This is reflected in an unusually high density of strongholds. The Meetschow site was of major importance for several centuries, even when political power changed. Saxons, Franks, Slavs and Germans all kept their main fortification at this place - obviously because of its topographical position, controlling the intersection of a water route and a land route. The significance of Meetschow ended with the end of the 10th c. and was declining until the final abandonment. Lenzen on the other bank of the river took over the functions of Meetschow and developed into the administrative and political centre of the region. Geoarchaeological research revealed evidence for a short phase of heavy natural flooding events sometime between 950 and ca. 980 A.D. Its impact on the topographical situation around the Höhbeck is discussed in the light of the political situation. The paper focuses on the coincidences in the history of strongholds and flood activity in the 8th-10th c. at the Höhbeck. It is stressed that the documented large scale natural events should be possible to detect in a wider area of northern Europe. © 2014 Elsevier Ltd and INQUA.

The aim of the cooperative research project was the development of a wood-cement in-situ concrete used as local filler and stiffening element in wooden ceiling elements. For further processing, only water should be added to the mineralized particles, whereby the amount of added water is relevant to the adjustment of the consistence and fl owing characteristics. Portland cement was used as binding component. Particle residues of Scots Pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.) from sanding with 60 grit paper, as filling components, were supplied by Lignotrend GmbH, an industrial manufacturer of solid wood structural elements (cross laminated timber) and project partner. The mineralization of these wood particles has also been studied. Three different ways to accelerate the hydration of the cement and therefore to counteract the effect of the so called cement poisons were examined. Moreover, the compressive strength of hardened concrete had to be set to not less than 3.2 N/mm2, which was also examined. © 2015, Journal Drvna Industrija. All rights reserved.

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