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- Adamopoulos, Stergios, et al.
(författare)
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Impregnation of timber and regulations applied to preservation practice in Greece
- 1998
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Konferensbidrag (refereegranskat)abstract
- The practice of wood preservation in Greece was started about 80 years ago and refer to creosote-treated timber used in ground contact (i.e. railway sleepers, poles). At present, three creosote impregnation plants and thirteen CCA or CCB units exist in Greece treating about 90.000 m3 of wood per year. Most of the research on wood preservation has been carried out in the last 15-20 years and refer to the application of creosote and water soluble preservatives (CCA, CCB) to native wood species. However, research on a number of specific topics of wood impregnation is lacking. Impregnation of wood is of great importance for Greece, a country with great wood deficit, and, for this reason, the elongation of wood durability is strongly desirable. On the other hand, the environmentally safe impregnation of timber and the use of preservatives in a non-hazardous manner to humans or animals are gaining an increasing importance. There are some national and EU regulations applied to the use of preservatives, while the Greek Organization of Standardization (ELOT) is responsible for approving European standards. The organizations of Greek Telecommunication, Electricity and Railway apply their own standards.
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| 3. |
- Carlsson, Peter, et al.
(författare)
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Optimization, a tool with which to create an effective drying schedule
- 1998
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Ingår i: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 52:5, s. 530-540
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Tidskriftsartikel (refereegranskat)abstract
- A method for defining effective schedules for kiln drying of wood is presented. The method is designed in such a way that it proposes an optimized variation of temperature and humidity which yields the minimum total drying time, with the condition that the moisture content and the deformation not exceed specified limits after the drying and that the stress not exceeds a specified level at any time during the drying process in order to avoid crack development. To demonstrate the capability of the optimization method numerical results are presented. It should be noted that ill this first approach, drying starts from moisture content corresponding to the fibre-saturation point, i.e. approximate to 30%).
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| 4. |
- Carlsson, Staffan, et al.
(författare)
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Utvärdering av deplacementmetod med vatten för bestämning av träets torrdensitet.
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Evaluation of the deplacement method with water for determination of dry wood density.by Staffan Carlsson, Stephan Eskilander and Dick SandbergAbstractA new method (SP-method) for determination of wood density at 12 % moisture content has been developted at the Swedish National testing and Research Institute (SP). The method is a futher development of the deplacement method with water as. The volume of the specimens is determined with use of Archimeds principle. The specimen is immersed in water and a computer program compensate for errors in the measurement as a result of wateruptake in the specimen.This investigation describes the correlation between the dry density of wood, determined by the SP-method and a "traditional" method. Traditional method means that the dimensions of the specimen are measured with a slide-calliper in order to calculate the volume of the specimen. The test materials were taken from Scots pine and Norway spruce with dimension 40 x 60 x 120 mm.The results show a difference less than 3 % between dry density determined by the two methods. The correlation coefficient (R2) was 0.99 when linear regression was used. Repetition test showed mean deviation of 0.2 % when dry density for same specimens were determined two times with the SP-method.
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| 9. |
- Dahlblom, O., et al.
(författare)
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Simulation of wood deformation processes in drying and other types of environmental loading
- 1996
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Ingår i: Annales des Sciences Forestieres. - : Elsevier. - 0003-4312 .- 1878-6545. ; 53:4, s. 857-866
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Tidskriftsartikel (refereegranskat)abstract
- Deformation processes in wood exposed to drying and other types of environmental loading are simulated by use of the finite element method. In the material model applied, the orthotropic structure of the wood material is considered. The differences of properties in the longitudinal, radial and tangential directions for stiffness parameters as well as for moisture shrinkage parameters are taken into account. As an illustration of possible application areas, the deformation development of boards during drying is simulated. In the analyses, the influence of spiral grain and the variation of wood properties with the distance from the pith are considered. The simulation yields information about unfavourable deformations that develop during the drying process., Le processus de déformation du bois exposé au séchage et autres types de charges environnementales est simulé par la méthode des éléments finis. La structure orthotropique du bois est prise en considération sur le modèle de matériel utilisé. Les différences existant au niveau des propriétés des directions longitudinales, radiales et tangentielles sont prises en compte pour les paramètres de rigidité et de contraction par humidité. Une des possibilités du champ d'applications est illustrée par le fait que l'évolution de la déformation des planches pendant le séchage est simulée. À l'échelon des analyses, l'influence du grain spiral et la variation des propriétés du bois avec la distance depuis la moelle sont pris en compte. La simulation permet d'obtenir des informations concernant l'évolution des déformations défavorables pendant le processus de séchage.
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