| 1. |
- Brischke, C., et al.
(författare)
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Modeling the material resistance of wood—part 2 : Validation and optimization of the meyer-veltrup model
- 2021
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Service life planning with timber requires reliable models for quantifying the effects of exposure-related parameters and the material-inherent resistance of wood against biotic agents. The Meyer-Veltrup model was the first attempt to account for inherent protective properties and the wetting ability of wood to quantify resistance of wood in a quantitative manner. Based on test data on brown, white, and soft rot as well as moisture dynamics, the decay rates of different untreated wood species were predicted relative to the reference species of Norway spruce (Picea abies). The present study aimed to validate and optimize the resistance model for a wider range of wood species including very durable species, thermally and chemically modified wood, and preservative treated wood. The general model structure was shown to also be suitable for highly durable materials, but previously defined maximum thresholds had to be adjusted (i.e., maximum values of factors accounting for wetting ability and inherent protective properties) to 18 instead of 5 compared to Norway spruce. As expected, both the enlarged span in durability and the use of numerous and partly very divergent data sources (i.e., test methods, test locations, and types of data presentation) led to a decrease in the predictive power of the model compared to the original. In addition to the need to enlarge the database quantity and improve its quality, in particular for treated wood, it might be advantageous to use separate models for untreated and treated wood as long as the effect of additional impact variables (e.g., treatment quality) can be accounted for. Nevertheless, the adapted Meyer-Veltrup model will serve as an instrument to quantify material resistance for a wide range of wood-based materials as an input for comprehensive service life prediction software. © 2021 by the authors.
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| 2. |
- Brischke, C., et al.
(författare)
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Modelling the material resistance of wood—Part 3 : Relative resistance in above and in ground situations—Results of a global survey
- 2021
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Durability-based designs with timber require reliable information about the wood properties and how they affect its performance under variable exposure conditions. This study aimed at utilizing a material resistance model (Part 2 of this publication) based on a dose–response approach for predicting the relative decay rates in above-ground situations. Laboratory and field test data were, for the first time, surveyed globally and used to determine material-specific resistance dose values, which were correlated to decay rates. In addition, laboratory indicators were used to adapt the material resistance model to in-ground exposure. The relationship between decay rates in-and above-ground, the predictive power of laboratory indicators to predict such decay rates, and a method for implementing both in a service life prediction tool, were established based on 195 hardwoods, 29 softwoods, 19 modified timbers, and 41 preservative-treated timbers. © 2021 by the authors..
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| 3. |
- Popescu, Carmen-Mihaela, et al.
(författare)
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Structural characterization and mechanical properties of wet-processed fibreboard based on chemo-thermomechanical pulp, furanic resin and cellulose nanocrystals
- 2020
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003. ; 145, s. 586-593
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Tidskriftsartikel (refereegranskat)abstract
- Fibreboards are made of lignocellulosic fibres and synthetic adhesive which connect them. These synthetic adhesives, while relatively low-cost, are usually non-biodegradable and may cause health and environmental issues. Therefore, in recent years, there has been an increased demand for replacing these adhesives with bio-derived adhesives. The present study aims to develop fibreboards from chemo-thermomechanical pulp (CTMP) and a furanic resin based on prepolymers of furfuryl alcohol via wet-processing. To improve the bonding properties, maleic acid, aluminium sulphate, and cellulose nanocrystals (CNCs) were added. The resulting fibreboards were evaluated for their structural features and mechanical properties. The bending strength was improved when CNCs were added into the fibre's suspension, and the morphology indicated a more compact structure. The combination of the CTMP with CNC and Biorez resulted in the same mechanical behaviours as those noted for CTMP alone, the best performance being observed for the boards in which Al2(SO4)3 was added. Infrared spectroscopy and X-ray diffraction also proved the presence of cellulose nanocrystals and resin in the boards by increased specific bands intensity and crystallinity index, respectively.
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| 4. |
- Treu, A., et al.
(författare)
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Durability and protection of timber structures in marine environments in Europe : An overview
- 2019
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Ingår i: BioResources. - : North Carolina State University. - 1930-2126. ; 14:4, s. 10161-10184
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Tidskriftsartikel (refereegranskat)abstract
- Timber structures in marine applications are often exposed to severe degradation conditions caused by mechanical loads and wood-degrading organisms. This paper presents the use of timber in marine environments in Europe from a wood protection perspective. It discusses the use of wood in coastline protection and archeological marine wood, reviews the marine borer taxa in European waters, and gives an overview of potential solutions for protection of timber in marine environments. Information was compiled from the most relevant literature sources with an emphasis on new wood protection methods; the need for research and potential solutions are discussed. Traditionally, timber has been extensively utilized in a variety of marine applications. Although there is a strong need for developing new protection systems for timber in marine applications, the research in this field has been scarce for many years. New attempts to protect timber used in marine environments in Europe have mainly focused on wood modification and the use of mechanical barriers to prevent colonization of marine wood borers. The importance of understanding the mechanisms of settlement, migration, boring, and digestion of the degrading organisms is key for developing effective systems for protecting timber in marine environments
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| 5. |
- Meyer-Veltrup, Linda, et al.
(författare)
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The combined effect of wetting ability and durability on outdoor performance of wood : development and verification of a new prediction approach
- 2017
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Ingår i: Wood Science and Technology. - : Springer Verlag. - 0043-7719 .- 1432-5225. ; 51:3, s. 615-637
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Tidskriftsartikel (refereegranskat)abstract
- Comprehensive approaches to predict performance of wood products are requested by international standards, and the first attempts have been made in the frame of European research projects. However, there is still an imminent need for a methodology to implement the durability and moisture performance of wood in an engineering design method and performance classification system. The aim of this study was therefore to establish an approach to predict service life of wood above ground taking into account the combined effect of wetting ability and durability data. A comprehensive data set was obtained from laboratory durability tests and still ongoing field trials in Norway, Germany and Sweden. In addition, four different wetting ability tests were performed with the same material. Based on a dose–response concept, decay rates for specimens exposed above ground were predicted implementing various indicating factors. A model was developed and optimised taking into account the resistance of wood against soft, white and brown rot as well as relevant types of water uptake and release. Decay rates from above-ground field tests at different test sites in Norway were predicted with the model. In a second step, the model was validated using data from laboratory and field tests performed in Germany and Sweden. The model was found to be fairly reliable, and it has the advantage to get implemented into existing engineering design guidelines. The approach at hand might furthermore be used for implementing wetting ability data into performance classification as requested by European standardisation bodies.
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| 6. |
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| 7. |
- Olsson, Sara, et al.
(författare)
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A SEM study on the use of epoxy functional vegetable oil and reactive UV-absorber as UV-protecting pretreatment for wood
- 2015
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Ingår i: Polymer degradation and stability. - : Elsevier BV. - 0141-3910 .- 1873-2321. ; 113:SI, s. 40-45
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigates the ageing performance of a UV protective system for wood, comprising the reactive UV absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP) and epoxy functional vegetable oils (linseed and soybean oil). Scots pine samples of radial or cross-sectional surfaces were treated using a combination of the two components, or using only one of the oils. The treated samples were then aged in a Weather-Ometer for 2 x 60 h and analysed using VPSEM to follow the degradation of the wood substrate in the exact same spot before, during and after ageing. The results of the radial surfaces show slightly less degradation of samples treated with a combination of HEPBP and oil, and for the cross-sectional surfaces an even stronger protective effect is visible. For samples treated with only one of the two oils, no improvement was detectable. The radial surfaces were also analysed using FTIR where the results indicate presence of the protective treatment even after 120 h of exposure. Overall the combined pretreatment of HEPBP and epoxy functional linseed oil was concluded to have a photo-stabilising effect of the wood substrate.
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| 8. |
- Sandin, Gustav
(författare)
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Life cycle assessment in the development of forest products : Contributions to improved methods and practices
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The prospect of reducing environmental impacts is a key driver for the research and development (R&D) of new forest products. Life cycle assessment (LCA) is often used for assessing the environmental impact of such products, e.g. for the purpose of guiding R&D. The aim of this thesis is to improve the methods and practices of LCA work carried out in the R&D of forest products. Six research questions were formulated from research needs identified in LCA work in five technical inter-organisational R&D projects. These projects also provided contexts for the case studies that were used to address the research questions. The main contributions of the research are as follows:Regarding the planning of LCA work in inter-organisational R&D projects, the research identified four characteristics that appear to be important to consider when selecting the roles of LCAs in such projects: (i) the project’s potential influence on environmental impacts, (ii) the degrees of freedom available for the technical direction of the project, (iii) the project’s potential to provide required input to the LCA, and (iv) access to relevant audiences for the LCA results.Regarding the modelling of future forest product systems, it was found that (i) it is important to capture uncertainties related to the technologies of end-of-life processes, the location of processes and the occurrence of land use change; and (ii) the choice of method for handling multi-functionality can strongly influence results in LCAs of forest products, particularly in consequential studies and in studies of relatively small co-product flows.Regarding the assessment of environmental impacts of particular relevance for forest products, it was found that using established climate impact assessment practices can cause LCA practitioners to miss environmental hot-spots and make erroneous conclusions about the performance of forest products vis-à-vis non-forest alternatives, particularly in studies aimed at short-term impact mitigation. Also, a new approach for inventorying water cycle alterations was developed, which made it possible to capture catchment-scale effects of forestry never captured before.To connect the LCA results to global challenges, a procedure was proposed for translating the planetary boundaries into absolute product-scale targets for impact reduction, e.g. to be used for evaluating interventions for product improvements or for managing trade-offs between impact categories.
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