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VOLUME 60, ISSUE 6/2019

3D cellulose mouldings: dewatering behaviour and process optimisation

Language: English
Pages: 5 - 10
Authors: René Kleinert, Tilo Gailat, Harald Großmann

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With respect to the politically and socially accelerated transformation towards a bio-economy, the demand for sustainable materials is put on a new level. To accelerate the laboratory process for the production of pure cellulose mouldings from highly fibrillated wood fibres (FibCell) it is necessary to analyse the impact of all relevant process parameters. Since the production of the mouldings starts from a highly diluted aqueous fibre suspension dewatering trials were carried out using Design of Experiment (DoE). The results clearly show the strong impact of grammage and temperature during the dewatering step and allow deriving optimization means. According to the findings the area of dewatering should be as high as possible and the temperature should be raised up to maximal 99 °C. This would reduce filtration resistance and would path the way to process cellulose suspensions into mouldings in a far more reasonable way.

An analysis of temperature and humidity measurements within CLT walls over a period of two years

Language: German
Pages: 11 - 17
Authors: Karl Entacher, Thomas Demschner, Hermann Kirchmayr, Jürgen Leonhartsberger

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This report contains a statistical evaluation of sensor data from humidity and temperature measurements within an insulated and uninsulated cross laminated timber wall over a period of two years. Three sensors were implemented into each wall, at the inner edge, in the middle and at the outer edge of the cross laminated timber element. Indoor and outdoor sensors complete the measurement setup. The project was carried out in Austria in cooperation with Stora Enso at Ybbs and the Holztechnikum Kuchl. The evaluation of the data demonstrates which temperature and humidity fluctuations a cross laminated timber wall can be exposed to over the years. The uninsulated wall in particular is subject to very high temperature and humidity differences with large seasonal fluctuations. The influence of the insulation is represented at the comparable places in the wall.

Modelling of wood cutting processes; Part 1: Introduction and basic considerations

Language: German
Pages: 18 - 25
Authors: Christian Gottlöber, André Wagenführ

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Modelling is the base of planning, forecasting and optimizing of wood cutting processes. Since long time ago many researches trying to find effective possibilities to get useful results therefor. Modelling means the finding of a single formula or a set of equations describing the dependency of certain input variables to certain output magnitudes of the process. The more the inputs and the more the variability of the material properties the more difficult and unreliable is the modelling result mostly. Especially the varying properties of wood as a natural, hygroscopic, inhomogeneous and anisotropic material make the modelling of wood cutting processes to a general challenging subject. Within the cutting process some output magnitudes are of interest representing the efforts and the benefits of the process. In terms of wood cutting the cutting capacity, cutting quality, the cutting energy respectively the cutting forces, the tool wear and the emissions of noise and dust are the categories of these magnitudes modelling is aiming. Input variables or influencing factors are the geometrical, kinematical and material properties which can be defined for the cutting process e. g. as wood species, moisture content, cutting direction, edge angles, cutting speed and chip thickness. Part 1 of the publication focuses on an introductory description of the situation, a systematic analysis of the machining process on wood and wood-based materials and the identification of levels of consideration for process modelling. In part 2, different modelling strategies and types as well as related model examples and possibilities of determining quantities using available sensors are discussed against the background of future requirements in autonomous, intelligent machines (smart machines).

The fluorescence lifetime in wood technology

Language: German
Pages: 26 - 30
Authors: Henry Burkhardt

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At the Institut für Holztechnologie Dresden (IHD) a confocal laser scanning microscope (CLSM) with equipment for time-correlated single photon counting (TCSPC) was acquired. It enables the determination of the fluorescence lifetime with spatial resolution on surfaces. This property can be used to obtain information about the chemical composition of the surface. In this article the fluorescence lifetime imaging is presented as a measuring method and some exemplary measuring tasks from the wood technology are mentioned, in whose solution the decay of the fluorescence at the surface of a sample can be used as an indicator.

Particleboard based on wood waste material bonded by leftover cakes of rape oil; Part 1: The mechanical and physical properties of particleboard

Language: English
Pages: 31 - 39
Authors: Mahmood Hameed, Eric Rönnols, Torleif Bramryd

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Alternatives to fresh wood and urea-formaldehyde as a synthetic adhesive system and other fossil origin adhesive systems are required. Wood waste materials are normally used for biofuel production or waste incineration. From environmental perspective, it is favourable to recycle wood material and use the concept of multiple sequential use, rather than just burning it for short-term energy production. The objective of this study was to investigate the feasibility of manufacturing particleboard from wood waste bonded by an adhesive system based on leftover cakes of rape oil in natural state complying with the European standard EN 312 (2010). The particleboards were produced with a target density of 640 kg/m³. For each panel variant the mechanical and physical properties were analysed. The results point out that it is possible to manufacture three-layered particleboard variants based on recycled wood waste material (type AI and AII) and bonded by a rape resin based on leftover cakes of rape oil in natural state. Furthermore, as a function of the used rape resin as a new adhesive system, the three-layered rape resinbonded particleboard variants show sufficient physical and mechanical properties complying with the standards of EN 312 (2010) and fulfilling the requirements of particleboard type P2. Specifically, the values of the modulus of elasticity (MOE), obtained for three-layered rape resinbonded particleboard variants, are higher than the limit listed in the standard. However, the results of internal bond (IB), achieved for three-layered rape-resin-bonded particleboard based on wood waste type AI are higher than the required values of European standard EN 312 (2010) for particleboard type P2.

Development of a monitoring system based on fibre-optic sensor technology that can be integrated into furniture constructions

Language: German
Pages: 40 - 43
Authors: Jens Wiedemann, Lars Blüthgen, Elke Thiele, Michael Kuhne

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Demographic change and an increasing shortage of skilled workers require new solutions in the area of care for people in need or older people. In particular, aids are needed to support nursing staff or caring relatives and to provide physical and temporal relief. The aim of a research project was therefore to develop a low-cost monitoring system based on textile-integrated fibre-optic sensor technology that can be combined with existing furniture systems. This article provides insights into the measurement principle used, describes the relationship between sensor topology and signal effect and summarises the results of the project.

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