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VOLUME 51, ISSUE 2/2010

Swelling of cross-laminated wooden panels; Part 2: Partial restrained swelling

Language: German
Pages: 5 - 10
Authors: Sebastian Clauß, Ulrike Kröppelin, Peter Niemz

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Internal stresses in multilayered solid wood boards during climate change are caused by the crosswise gluing of their single layers. These stresses may partly be released in cracks during drying. In the current investigation we measured the free swelling, the swelling pressure and the internal stresses after a climate change from 20° C/35 % to 20° C/85 % RH. Therefore we tested single layers of spruce wood (Picea abies Karst.) and MDF as well as multilayered solid wood boards. In part 1 of the publication we presented an overview of free and restrained swelling and described the used methods and materials. The partial restrained swelling and the internal stresses are subject of the second part. By means of a three dimensional swelling pressure measurement and determination of the internal stresses between the layers we could make assumptions about the stress state of the boards after changed environmental conditions. The calculated swelling pressure was significantly lower than the internal stresses. According to this, the main part of the stresses is transmitted by the bond line and released by plastic deformations.

Changes in colour and mechanical properties of woodplastic composites (WPC) based on polyolefins after QUV-weathering and water soaking tests; Part 2: Mechanical property changes

Language: German
Pages: 11 - 16
Authors: Anke Schirp, Brigitte Köhler, Kirsten Wittenberg

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Mechanical properties and colour changes of polyolefin-based WPC after artificial weathering (QUV) for 4032 hours were determined according to modified DIN EN 927-6 (2006). In addition, water uptake and swelling of WPC products were determined

without prior weathering. The mechanical properties of the tested WPC were strongly affected in some instances; however, a significant reduction in strength properties was also determined for the wood species Bangkirai under the same conditions. Thickness swelling of the various WPC after 28 days of water soaking varied considerably with values raging from 1,2 % to 6,4 %. Swelling in width and length after water soaking was between 0.5 % and 1 %. The results for the colour changes of WPC following artificial weathering are shown in part 1 of this series.

Technologies and manufacturing equipment for the forming of solid wood; Part 1 Methods of plasticization

Language: German
Pages: 17 - 24
Authors: Ulrich Schwarz

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The non-cutting shaping of wood is a centuries-old technology. With the application of CNC milling technology, this kind of forming has almost disappeared. This trend is strengthening implementation of curved elements in furniture manufacturing. Nevertheless, there are in the Federal Republic of Germany only a few companies who have mastered this technology. The literature shows that there is a very high level of knowledge which is still available but not used anymore.

Detection of 27 wood decay fungi by DNA chip technology

Language: German
Pages: 25 - 30
Authors: Daniel Müller, Natalya Rangno, Caroline Hiller, Kordula Jacobs, Dana Tusche, Sebastian Begemann, Wolfram Scheiding, Werner Brabetz

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According to DIN 68800-4 (1992), the specific identification of fungi is essential for accurate appraisal and elimination of fungus damage to wooden constructions. In addition to conventional diagnostics objective, standardized and highly sensitive

molecular biological methods have been increasingly used. In cooperation with Institut für Holztechnologie Dresden gemeinnützige GmbH (IHD) Biotype Diagnostic GmbH developed a DNA microarray for the unambiguous identification of 27 relevant wood-destroying basidiomycetes. The specificity of these DNA probes was demonstrated by using the polymerase chain reaction (PCR) and by microarray detection technology. By using a two-step assay, comprising the PCR amplification of the ITS region with basidiomycete specific primers and the ALR with species and genus specific DNA probes, a high analytical specificity for fungal detection is approved. The correct species determination of practice samples confirmed that the Mycotype® BasidioQS Microarray Detection Kit is suitable for the identification and differentiation of wood decay fungi in routine diagnostics.

Qualitative classification of softwood round timber according to European standard EN 1927, part 1

Language: German
Pages: 31 - 37
Authors: Udo Hans Sauter, Stephan Verhoff

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In the last years the existing pre-standard prEN 1927, part 1- 3 has been revised and published as European standard in 2008. The standard includes regulations concerning quality classification of the following softwood roundwood species: spruces and firs (part 1), pines (part 2) and larches and Douglas fir (part 3). For Germany the previous work on a European scale is important, because the national regulations are also under revision and the intension is, to integrate important contents of European standards into those national regulations. The first part of this paper deals with the background and basic principles of the standard in general and describes the European standard for

spruces and firs. The second part, which will follow later, will describe the remaining softwood species and will give an overall view.

Furniture supply chain management – a key to success? Why many companies still don’t seem to care, despite low profit margins

Language: German
Pages: 38 - 43
Authors: Nicholas Boone, Tim Quisbrock

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Supply chain management is frequently underestimated in the furniture industry. Thus, considerable approaches to improve profitability are left untouched. An empirical study shows that integrated IT-based operations are considered to be of exceptional

importance for a company’s success. However, in the furniture industry, few IT or supply chain standards have been successfully implemented. In the study, forecasting and sales control were identified as key areas for improvement. Logistics service

providers were not considered to be of great importance. All in all, there is a lack of scientific research with regard to provensuccessful concepts for systematically identifying and exploiting supply chain management potentials in the furniture industry.

Review: Market potential of Wood-Plastic-Composite (WPC) boards

Language: German
Pages: 44 - 50
Authors: Hans Korte

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The most potential market for WPC-panels is concrete formwork, mostly panel wall formwork. Concrete formwork on one hand is a very big market on the other hand plastic panels and composite panels made from plywood and plastic surfaces are

already introduced into the market. Therefore the market introduction of WPC-panels is easy to argue. Container floors of transportation containers show a big market potential, too. WPC may compete with plywood due to its higher durability against microbial attack. The market for façade elements shows a high diversity. Technically WPC-panels may have a high potential in façade application but market introduction is much more regulated than in other fields. Facades need to have a CE-certificate. Solid plastic panels may be replaced by WPC-panels in caravan, yacht or interior applications. There is also interest in panels for racks in food industry for easy cleaning purposes. Easy cleaning and hygiene control are favourable for boxes in hog pens. Sandwich structures may replace hollow chamber profiles which are difficult in hygiene control.

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