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  • 1.
    Alfredsen, Gry
    et al.
    Norwegian Forest and Landscape Institute, Norway.
    Pilgård, Annica
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad.
    Postia placenta decay of acetic anhydride modified wood: effect of leaching2014Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, nr 3, s. 162-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is well established that acetylation of wood by the use of acetic anhydride is able to impart a significant degree of decay resistance. The aim of this work was to study how a standardized leaching procedure with water (EN 84) affected the degradation of acetic anhydride modified samples by the brown rot fungi Postia placenta compared to no leaching prior to incubation. Three different levels (low, medium, and high) of acetic anhydride modified Southern yellow pine (SYP; Pinus spp.) were tested. The samples were harvested after 4 and 28 weeks. Wecompared changes in mass loss, wood moisture content, fungal DNA, and gene expression from five genes. If leaching changes the acetylated samples and makes them more susceptible for fungal deterioration, the expected effect would be higher levels of these parameters. Generally, leaching resulted in few differences between leached and nonleached samples at low levels of acetylation, while no changes were found for the highest acetylation level. No differences were found in gene expressions after 28 weeks. The possible protection of acetylated wood against oxidative fungal degradation is suggested to be interpreted in combination with the lowered wood moisture content.

  • 2.
    Berglund, Anders
    et al.
    Luleå University of Technology, Sweden.
    Dahlquist, Simon
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Grönlund, Anders
    Luleå University of Technology, Sweden.
    Detection of saw mismatch in double-arbor saw machines using laser triangulation2013Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 8, nr 4, s. 219-225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the sawing process of a sawmill, not only are the target sizes of great importance, but the saw mismatch that may occur in double-arbor saw machines is also an essential parameter that affects the planing allowance, as well as the quality of the sawn products. In this study, a newly developed measurement equipment for detecting saw mismatch in the green sorting line of a sawmill has been evaluated in an initial experimental test. The obtained data has been compared to manual measurements of saw mismatch with good results. Also, based on a small sample, 75-95% of the boards with a maximal saw mismatch exceeding 0.5 mm are detected. The rate of detection depends on the number of cameras used.

  • 3.
    Blomqvist, Lars
    et al.
    RISE Research Institutes of Sweden, Samhällsbyggnad, Bygg och fastighet.
    Ormarsson, Sigurdur
    Linnaeus University, Sweden.
    Ziethén, Rune
    RISE Research Institutes of Sweden, Samhällsbyggnad, Bygg och fastighet.
    Stress distribution in veneers under lamination and simultaneously bending: an experimental and numerical investigation2023Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, nr 3, s. 995-1002Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Laminated veneer products (LVPs) are veneers glued together into a predetermined shape. Experimental and numerical investigations were performed under lamination and simultaneously bending of veneer laminate to study the stress distribution in the laminate. Laminates of different thicknesses were made of peeled veneers of European beech. The veneers were coated with adhesive, inserted in a mould which had the shape of a semicircle, and finally pressed at 20°C to a laminate. Two Teflon-polymer films including sensors for measurement of the contact pressure were placed on both sides of the laminate to measure the local contact pressure (contact stress) between the laminate and the mould. At the beginning of the bending process, the contact stresses were locally distributed over the laminate in a similar pattern as in a three-point bending; after the laminate was further bent, the stress distribution rearranged to be as in four-point bending. In the end of the moulding, the local contact stresses increased over the entire laminate and reached a ‘peak-value’ over bent area in the middle part of the mould. A finite-element model was created to study the bending process. Regarding the overall development of the contact stress variations, the experimental and the numerical results agreed.

  • 4.
    Blomqvist, Lars
    et al.
    RISE Research Institutes of Sweden, Samhällsbyggnad.
    Sterley, Magdalena
    RISE Research Institutes of Sweden, Bioekonomi och hälsa.
    Influence of pressure on bond-line shear strength in laminated veneer products2022Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 17, nr 6, s. 1020-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the bond-line strength of different bonding pressure of veneers in dry (9% moisturecontent) and wet (immersed in water) conditions was investigated. The results show that peeledEuropean beech veneers need approximately 0.5– 1.2 MPa pressure to achieve a proper bond-linewhen a urea-formaldehyde adhesive was used. The pressure variation within this range did notsignificantly affect the strength of the dry veneer, but the strength of the wet veneers decreasedas the bonding pressure increased. The type of failure varied, especially for the wet veneers. Athigh pressure, the wood were stronger than the cohesive strength of the adhesive and thestrength of the adhesion between the adhesive and the wood. High pressure, however, caused acompression of the bond-line and resulted in a lack of adhesion.

  • 5. De Vetter, Liesbeth
    et al.
    Pilgård, Annica
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Treu, Andreas
    Westin, Mats
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Van Acker, Joris
    Combined evaluation of durability and ecotoxicity: A case study on furfurylated wood2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 30-36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modified wood is commercially available and merchandized as a new, environmentally friendly and durable wood species. However, there are no standards focusing on the evaluation of modified wood. Combining resistance against fungal decay and good ecotoxicological properties may be a start. In this study softwood and hardwood species were furfurylated using different treatment processes and treating solutions. The durability was determined by exposing the treated wood to a range of Basidiomycetes and the ecotoxicity was studied on two aquatic organisms. It was the purpose to come to a strategy and how to unite efficacy and ecotoxicity, since this is important in product development. The results show that the selection of fungus used for mass loss determination and the choice of ecotoxicity method is decisive, confirming that a combination of methods is valuable. A tiered approach to find the optimal treatment seems the best option. First, adequate protection against wood-rotting fungi should be attained, followed by ecotoxicity evaluation of the wood leachates. If necessary, the optimization process should be repeated until both durability and ecotoxicity are within satisfactory limits. This process could be extended with other evaluation criteria, e.g. dimensional stability of the modified wood or a risk analysis of its leachate.

  • 6. Ekevad, Mats
    et al.
    Lundgren, Nils
    Flodin, Jens
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Drying shrinkage of sawn timber of Norway spruce (Picea abies): Industrial measurements and finite element simulations2011Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 6, nr 1-2, s. 41-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industrial measurements of green and dry cross-section dimensions were performed for 189 Norway spruce (Picea abies) centre-yield boards with dry dimensions 51 × 149 mm. Two, three or four boards were sawn from each log, depending on log size. Different approaches were used for simulations of cross-section shrinkage during drying. An analytical model, an elastic, an elastic– mechanosorptive and an elastic– plastic finite element simulation model were tested. Thickness and width shrinkage and deformation were simulated. Shrinkage results were compared with each other and with the experimental results. All simulation models gave roughly the same degree of agreement with experimental results except for the centre board from the three-board sawing pattern. For the other boards, the analytical model was not generally better or worse than the results from the finite element models. Shrinkage deformations in finite element models that included mechanosorption or plasticity were nearly the same as for the elastic finite element model except for the centre board of the three-board sawing pattern. The mechanosorptive model was the best model for the shrinkage of the centre board of this sawing pattern except for mid-thickness shrinkage. Comparison between the different finite element simulation models of stresses in the centre board revealed large differences.

  • 7.
    Englund, Finn
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Bryne, Lars Elof
    Ernstsson, Marie
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor.
    Lausmaa, Jukka
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Wålinder, Magnus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Some aspects on the determination of surface chemical composition and wettability of modified wood2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 80-85Artikel i tidskrift (Refereegranskat)
  • 8.
    Englund, Finn
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Bryne, Lars Elof
    Ernstsson, Marie
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor.
    Lausmaa, Jukka
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Wålinder, Magnus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP - Sveriges Tekniska Forskningsinstitut, SP Trä.
    Spectroscopic studies of surface chemical composition and wettability of modified wood2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 80–85-Artikel i tidskrift (Refereegranskat)
  • 9. Fechter, J-O.
    et al.
    Englund, Finn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Emission of glycol ethers from medium-density fibreboard surfaces coated by a waterborne lacquer under different drying conditions2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, nr 1-2, s. 21-28Artikel i tidskrift (Refereegranskat)
  • 10. Fechter, J-O.
    et al.
    Englund, Finn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Lundin, A
    Association between temperature, relative humidity and concentration of volatile organic compounds from wooden furniture in a model room2006Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 1, nr 2, s. 69-75Artikel i tidskrift (Refereegranskat)
  • 11.
    Fredriksson, Magnus
    et al.
    Luleå University of Technology, Sweden.
    Broman, Olof
    Luleå University of Technology, Sweden.
    Persson, Fredrik
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Förädling och processer (TRf).
    Axelsson, Ann
    Luleå University of Technology, Sweden.
    Ah Shenga, Pedro
    Luleå University of Technology, Sweden.
    Rotational position of curved saw logs and warp of the sawn timber2014Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, nr 1, s. 31-39Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the development of scanning technology in sawmills, it is possible to optimise log rotational position when sawing. However, choosing a different rotational position than horns down might be detrimental for the board shape after drying, especially for curved logs. Thus, there is a need to investigate at what level of log curve it is possible to freely rotate logs without causing board warp. This study was carried out through a test sawing that was conducted at a sawmill situated in the middle of Sweden. The tests were made on 177 Norway spruce logs, with varying amount of curve. Half of the logs were sawn in the horns-down position, half were sawn rotated perpendicular to horns down. Log shape and warp of the dried boards were measured. The results indicated a relationship between board spring, log curve and choice of rotational position. Furthermore, board bow was related to log curve but not rotational position. It can be concluded that for straight logs, with a bow height of less than 15 mm, an unconventional rotational position does not cause excess spring in the boards. Bow and twist are not affected by the rotational position at all.

  • 12. Hameury, Stéphane
    et al.
    Sterley, Magdalena
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Magnetic resonance imaging of moisture distribution in Pinus sylvestris L. exposed to daily indoor relative humidity fluctuations2006Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 1, nr 3, s. 116-126Artikel i tidskrift (Refereegranskat)
  • 13.
    Honfi, Daniel
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Byggteknik. Lund University, Sweden.
    Time-variant reliability of timber beams according to Eurocodes considering long-term deflections2019Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 26, nr 3, s. 167-178Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to achieve a consistent level of failure probability, structural design codes are optimized using probabilistic methods. This optimization process traditionally focuses on the ultimate limit states (ULS). However, in the design of timber structures the performance of the structural members is often governed by the serviceability limit state (SLS) associated with different load levels than applied in the ULS. The probability of serviceability failure is strongly dependent on the loading sequence and the time-dependent response of timber; therefore, a time-variant probabilistic model is recommended to estimate them properly. This study aims to investigate the time-dependent reliability for long-term deflections of timber office and residential floor beams according to the specifications of the Eurocodes. A simple creep model is used to calculate the deflections and Monte Carlo simulation is carried out to determine the reliability index. It was found that the creep factor and the suggested deflection limits given in Eurocode 5 might not be appropriate to achieve the expected target reliabilities. To obtain a more consistent reliability, more suitable values for the mentioned parameters were suggested. However, the primary aim was to present a framework to determine appropriate deflection limits for structural codes.

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  • 14. Inoue, Masafumi
    et al.
    Kawai, Shuichi
    Wålinder, Magnus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Rowell, Roger
    Dimensional stabilization of compressed laminated veneer lumber by hot pressing in an airtight frame2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, nr 3-4, s. 119-125Artikel i tidskrift (Refereegranskat)
  • 15. Inoue, Masafumi
    et al.
    Morooka, Toshiro
    Norimoto, Misato
    Englund, Finn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Mechanism of partial fixation of compressed wood based on a matrix non-softening method2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, nr 3-4, s. 126-130Artikel i tidskrift (Refereegranskat)
  • 16.
    Johansson, Erik
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad. Luleå University of Technology, Sweden.
    Berglund, Anders
    Luleå University of Technology, Sweden.
    Skog, Johan
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad.
    Comparing predictability of board strength between computed tomography, discrete X-ray, and 3D scanning of Norway spruce logs2016Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 11, nr 2, s. 116-125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Strength graded boards of Norway spruce (Picea abies (L.) Karst.) are important products for many Scandinavian sawmills. If the bending strength of the produced boards can be predicted before sawing the logs, the raw material can be used more efficiently. In previous studies it is shown that the bending strength can be predicted to some extent using discrete X-ray scanning of logs. In this study, we have evaluated if it is possible to predict bending strength of Norway spruce boards with higher accuracy using computed tomography (CT) scanning of logs compared to a combination of discrete X-ray and 3D scanning. The method was to construct multivariate models of bending strength for three different board dimensions. Our results showed that CT scanning of logs produces better models of bending strength compared to a combination of discrete X-ray and 3D scanning. The main reason for this difference was the benefit of knowing the position of where the boards were cut from the logs and therefore detailed knot information could be used in the prediction models. Due to the small number of observations in this study, care should be taken when comparing the resulting prediction models to results from other studies.

  • 17.
    Lerman, Peter
    et al.
    Linnaeus University, Sweden.
    Scheepers, Gerhard
    RISE Research Institutes of Sweden, Samhällsbyggnad, Bygg och fastighet.
    Determination of a mass-transfer coefficient for wood drying by means of thermography2023Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, it was demonstrated that mass transfer and mass transfer coefficients related to the wood drying process can be satisfactorily quantified using thermography. The method was based on continuous measurements of the wood’s surface temperature, which were converted to a vapor pressure at the wood surface. The results showed that the values of the experimentally obtained transfer coefficients were in the same order of magnitude as values obtained with classical empirical correlations that apply in boundary layer theory. The measurements also showed that an average value of the mass transfer coefficient obtained during drying satisfactorily describes the complete process. The measurement set-up makes it possible to determine a surface potential accurately and continuously, which is useful in the assessment of wood drying processes. © 2023 The Author(s). 

  • 18.
    Lerman, Peter
    et al.
    Linnaeus University, Sweden.
    Scheepers, Gerhard
    RISE Research Institutes of Sweden, Samhällsbyggnad, Bygg och fastighet.
    Wiberg, Pär
    IKEA, Sweden.
    A laboratory setup for measuring the wood-surface temperature during drying by means of thermography2023Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, nr 2, s. 701-706Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The surface temperature of a drying wooden board is strongly related to the drying process. However, it is relatively difficult to determine the surface temperature accurately during drying. In this paper, an experimental setup for analyzing the wood surface during drying by thermal imaging as well as dry and wet-bulb temperature reference surfaces was tested. Spruce sapwood samples were dried in various climates and evaluated with respect to both mass loss and surface temperature. The experimental setup enabled both qualitative and quantitative analysis of the wood drying process. The results showed that thermal imaging enabled a detailed view of the drying progression. The distinct correlation between surface temperature and mass change showed that an accurate determination of a basic, often considered, and difficult-to-determine drying potential is possible. © 2022 The Author(s). 

  • 19.
    Markström, Emilia
    et al.
    Luleå university of technology, Sweden.
    Kitek Kuzman, Manja
    University of Ljubljana, Slovenia.
    Bystedt, Anders
    RISE - Research Institutes of Sweden, Bioekonomi, Biobaserade material.
    Sandberg, Dick
    Luleå university of technology, Sweden; Czech University of Life Sciences, Czech Republic.
    Use of wood products in multi-storey residential buildings: views of Swedish actors and suggested measures for an increased use2019Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 14, nr 6, s. 404-419Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many studies have shown that wooden buildings in general have a lower climate impact than buildings built of conventional materials such as concrete and steel. In Sweden, however, only about 10% of the multi-dwelling buildings are built with timber frames. The goal of this empirical study is to provide a broad picture of the views of Swedish actors regarding the use of wood products in multi-storey residential buildings and suggest measures for an increased use. A questionnaire concerning the use of wood products in construction was sent out to Swedish developers, main contractors, and architects and 100 answers were received. The study shows that the views of the groups of actors differ in some respects and factors that may either facilitate or be obstacles to an increased use of wood products were identified and discussed.

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  • 20.
    Olofsson, Linus
    et al.
    Luleå University of Technology, Sweden.
    Broman, Olof
    Luleå University of Technology, Sweden.
    Skog, Johan
    RISE - Research Institutes of Sweden, Bioekonomi, Biobaserade material.
    Fredriksson, Magnus
    Luleå University of Technology, Sweden.
    Sandberg, Dick
    Luleå University of Technology, Sweden.
    Multivariate product adapted grading of Scots pine sawn timber for an industrial customer, part 1: Method development2019Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 14, nr 6, s. 428-436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rule-based automatic grading (RBAG) of sawn timber is a common type of sorting system used in sawmills, which is intricate to customise for specific customers. This study further develops an automatic grading method to grade sawn timber according to a customer’s resulting product quality. A sawmill’s automatic sorting system used cameras to scan the 308 planks included in the study. Each plank was split at a planing mill into three boards, each planed, milled, and manually graded as desirable or not. The plank grade was correlated by multivariate partial least squares regression to aggregated variables, created from the sorting system’s measurements at the sawmill. Grading models were trained and tested independently using 5-fold cross-validation to evaluate the grading accuracy of the holistic-subjective automatic grading (HSAG), and compared with a re-substitution test. Results showed that using the HSAG method at the sawmill graded on average 74% of planks correctly, while 83% of desirable planks were correctly identified. Results implied that a sawmill sorting station could grade planks according to a customer’s product quality grade with similar accuracy to HSAG conforming with manual grading of standardised sorting classes, even when the customer is processing the planks further.

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  • 21.
    Olofsson, Linus
    et al.
    Luleå University of Technology, Sweden.
    Broman, Olof
    Luleå University of Technology, Sweden.
    Skog, Johan
    RISE - Research Institutes of Sweden, Bioekonomi, Biobaserade material.
    Fredriksson, Magnus
    Luleå University of Technology, Sweden.
    Sandberg, Dick
    Luleå University of Technology, Sweden.
    Multivariate product adapted grading of Scots Pine sawn timber for an industrial customer, part 2: Robustness to disturbances2019Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 14, nr 6, s. 420-427Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Holistic-subjective automatic grading (HSAG) of sawn timber by an industrial customer’s product outcome is possible through the use of multivariate partial least squares discriminant analysis (PLS-DA), shown by part one of this two-part study. This second part of the study aimed at testing the robustness to disturbances of such an HSAG system when grading Scots Pine sawn timber partially covered in dust. The set of 308 clean planks from part one of this study, and a set of 310 dusty planks, that by being stored inside a sawmill accumulated a layer of dust, were used. Cameras scanned each plank in a sawmill’s automatic sorting system that detected selected feature variables. The planks were then split and processed at a planing mill, and the product grade was correlated to the measured feature variables by partial least squares regression. Prediction models were tested using 5-fold cross-validation in four tests and compared to the reference result of part one of this study. The tests showed that the product adapted HSAG could grade dusty planks with similar or lower grading accuracy compared to grading clean planks. In tests grading dusty planks, the disturbing effect of the dust was difficult to capture through training.

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  • 22.
    Ormondroyd, Graham Alan
    et al.
    Bangor University, UK; University of Bath, UK.
    Källbom, Susanna K.
    KTH Royal Institute of Technology, Sweden.
    Curling, Simon F.
    Bangor University, UK.
    Stefanowski, B.K.
    Bangor University, UK.
    Segerholm, Kristoffer
    KTH Royal Institute of Technology, Sweden.
    Wålinder, Magnus E.P.
    RISE., SP – Sveriges Tekniska Forskningsinstitut. KTH Royal Institute of Technology, Sweden.
    Jones, Dennis
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Water sorption, surface structure and surface energy characteristics of wood composite fibres refined at different pressures2017Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, nr 4, s. 203-210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During fibre processing, wood fibres are subjected to a range of physical and chemical conditions sufficient to slightly alter their chemical composition and hence their ultimate performance when used in the manufacture of wood fibre-based composites. In order to better understand the effects of refiner conditions on material performance, wood fibres were subjected to processing at different refiner pressures (4, 6, 8 and 10 bar) and subsequently dried in a flash drier. The fibres were analysed for changes in surface area, surface energy, surface structure and water vapour sorption characteristics. The methods applied were nitrogen adsorption utilising the Brunauer–Emmett–Teller theory, inverse gas chromatography, scanning electron microscopy and dynamic vapour sorption. It was found that increasing refiner pressure resulted in fibres of lower surface area, accompanied by increasing dispersive surface energies up to operating refiner pressures of 8 bar. It was found with fibres refined at different pressures that as the refiner pressure increased the equilibrium moisture content of the fibre decreased at the set relative humidities. However, it was also noted that the hysteresis was not significantly different between each of the refiner pressures. The results suggest that different refiner pressures can be used to tune the surface characteristics which may be beneficial to product development and the improvement of the environmental profile of the wood fibre composites. 

  • 23.
    Pupure, LIva
    et al.
    Luleå University of Technology, Sweden.
    Varna, Janis
    Luleå University of Technology, Sweden.
    Joffe, Roberts
    RISE - Research Institutes of Sweden (2017-2019), Material och produktion, SICOMP. Luleå University of Technology, Sweden.
    Berthold, Fredrik
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Biobaserade material.
    Miettinen, Arttu
    University of Jyväskylä, Finland; Paul Scherrer Institute, Switzerland.
    Mechanical properties of natural fiber composites produced using dynamic sheet former2018Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 15, nr 2, s. 76-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Composites formed from wood fibers and man-made cellulosic fibers in PLA (polylactic acid) matrix, manufactured using sheet forming technique and hot pressing, are studied. The composites have very low density (due to high porosity) and rather good elastic modulus and tensile strength. As expected, these properties for the four types of wood fiber composites studied here improve with increasing weight fraction of fibers, even if porosity is also increasing. On the contrary, for man-made cellulosic fiber composites with circular fiber cross-section, the increasing fiber weight fraction (accompanied by increasing void content) has detrimental effect on stiffness and strength. The differences in behavior are discussed attributing them to fiber/ fiber interaction in wood fiber composites which does not happen in man-made fiber composites, and by rather weak fiber/matrix interface for man-made fibers leading to macro-crack formation in large porosity regions.

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  • 24. Rowell, Roger
    et al.
    Ibach, R.E.
    McSweeny, James
    Nilsson, Thomas
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Understanding decay resistance, dimensional stability and strength changes in heat-treated and acetylated wood2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 14-22Artikel i tidskrift (Refereegranskat)
  • 25.
    Salin, Jarl-Gunnar
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Modelling water absorption in wood2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, nr 3, s. 102-108Artikel i tidskrift (Refereegranskat)
  • 26.
    Salin, Jarl-Gunnar
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Wamming, Thomas
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Drying of timber in progressive kilns. Simulation, energy consumption and drying cost considerations2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 1&2, s. 12 to 20-Artikel i tidskrift (Refereegranskat)
  • 27.
    Salin, Jarl-Gunnar
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Wamming, Thomas
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Drying of timber in progressive kilns: Simulation, quality, energy consumption and drying cost considerations2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, nr 1-2, s. 12-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Progressive (semi-continuous) kilns for softwood drying are very common in Finland and Sweden and are used in some other countries too. A simulation program has been developed that covers all three types of this kiln. The program calculates the climate in the length direction of the kiln and moisture content, moisture profile, wood temperature, slicing test gap and stress development. Energy consumption and drying costs may also be determined. The temperature level is the most important parameter regarding kiln efficiency. Two-zone progressive kilns are found to be more efficient than single-zone kilns. Progressive kilns have lower energy consumption and drying costs than batch kilns. Experimental full-scale tests show that the timber quality from a progressive kiln is comparable to, or in some cases even better than, timber dried in batch kilns

  • 28.
    Sandberg, Karin
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Degradation of Norway spruce (Picea abies) heartwood and sapwood during 5.5 years’ above-ground exposure2008Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, nr 3&4, s. 83-93Artikel i tidskrift (Refereegranskat)
  • 29.
    Sandberg, Karin
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Byggande och boende (TRb).
    Mostolygin, Kirill
    Luleå University of Technology, Sweden.
    Hagman, Olle
    Luleå University of Technology, Sweden.
    Effect of lamellas annual-ring orientation on cracking of glulam beams investigated with computer tomography and image processing2013Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 8, nr 3, s. 166-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cracks in glulam beams can reduce their strength, depending on the crack's depth, length, and location and can also be a passage for the accumulation of water and dirt. To avoid cracks, the relationship between cracks (area of cracks, mm2) and annual-ring orientation in glulam beams of spruce (Picea abies), and pine (Pinus sylvestris) with different dimensions and surface treatments was investigated using RGB images of the surface and tomography images of the cross-sections. Image processing was used to measure characteristics visible in the photos such as crack area and lamella position in the beam. Combination of lamellas in lay up was measured from computer tomography images. Four types of combinations were defined; type 1 (pith side facing outward), types 2 and 3 (pith to the same side), and type 4 (pith sides meet pith side). It was found that the area close to the glue line in the lamellas in combination type 4 is the most subject to cracking, whereas combinations of type 1 show the highest resistance to cracking. This means that type 4 should not be used in glulam beams, because the lamellas shrink apart from each other causing stresses and resulting cracks.

  • 30.
    Segerholm, B.K.
    et al.
    KTH Royal Institute of Technology.
    Walkenström, P.
    IFP Research.
    Nyström, Birgitha
    RISE - Research Institutes of Sweden (2017-2019), Material och produktion, SICOMP.
    Wålinder, M.E.P.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Larsson Brelid, P.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Micromorphology, moisture sorption and mechanical properties of a biocomposite based on acetylated wood particles and cellulose ester2007Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 2, s. 106-117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the major issues in a long-term perspective for the use of wood-plastic composites (WPCs) in outdoor applications is the moisture sensitivity of the wood component and the consequent dimensional instability and susceptibility to biological degradation of the composite. In this work, the effects of using an acetylated wood component and a cellulose ester as matrix on the micromorphology, mechanical performance and moisture uptake of injection-moulded WPCs have been studied. Composites based on unmodified and acetylated wood particles, specially designed with a length-to-width ratio of about 5-7, combined with both cellulose acetate propionate (CAP) and polypropylene (PP) matrices were studied. The size and shape of the wood particles were studied before and after the processing using light microscopy, and the micromorphology of the composites was studied using a newly developed surface preparation technique based on ultraviolet laser irradiation combined with low-vacuum scanning electron microscopy (LV-SEM). The water vapour sorption in the composites and the effect of accelerated weathering were measured using thin samples which were allowed to reach equilibrium moisture content (EMC). The length-to-diameter ratio was only slightly decreased for the acetylated particles after compounding and injection moulding, although both the unmodified and the acetylated particles were smaller in size after the processing steps. The tensile strength was about 40% higher for the composite based on acetylated wood than for the composite with unmodified wood using either CAP or PP as matrix, whereas the notched impact strength of the composite based on acetylated wood was about 20% lower than those of the corresponding unmodified composites. The sorption experiments showed that the EMC was 50% lower in the composites with an acetylated wood component than in the composites with an unmodified wood component. The choice of matrix material strongly affected the moisture absorptivity of the WPC. The composites with CAP as matrix gained moisture more rapidly than the composites with PP as matrix. It was also found that accelerated ageing in a Weather-Ometer® significantly increased the moisture sensitivity of the PP-based composites.

  • 31.
    Segerholm, Kristoffer
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Walkenström, Pernilla
    Nyström, Birgitha
    RISE., Swerea, SICOMP.
    Wålinder, Magnus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Larsson Brelid, Pia
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Micromorphology, moisture sorption and mechanical properties of a biocomposite based on acetylated wood particles and cellulose ester2007Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 2, nr 3-4, s. 106-117Artikel i tidskrift (Refereegranskat)
  • 32.
    Skog, Johan
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Vikberg, Tommy
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Oja, Johan
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Sapwood moisture-content measurements in Pinus sylvestris sawlogs combining X-ray and three-dimensional scanning2010Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 5, nr 2, s. 91-96Artikel i tidskrift (Refereegranskat)
  • 33.
    Sterley, Magdalena
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP Trä.
    Gustafsson, P. J.
    Shear fracture characterization of green-glued polyurethane wood adhesive bonds at various moisture and gluing conditions2012Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 7, nr 2, s. 93-100Artikel i tidskrift (Refereegranskat)
  • 34.
    Vikberg, Tommy
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad. Luleå University of Technology, Sweden.
    Elustondo, Diego
    Luleå University of Technology, Sweden.
    Basic density determination for Swedish softwoods and its influence on average moisture content of wood packages estimated by measuring their mass2016Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 11, nr 4, s. 248-253Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, a set-up with a device measuring the mass of wood packages is examined as an aid to estimate the average moisture content (MC) of wood packages. As the basic density needs to be presumed in the set-up, an estimator of the basic density as a function of log diameter is determined for Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris). In total, 1920 specimens were collected at two different sawmills and analysed for this purpose. Specimens collected at the butt-end of pine had the greatest variation in basic density and it is recommended that they should be omitted when sawmills create their own functions for basic density estimation. Furthermore, the variation in basic density was shown to have the greatest impact on the estimated MC. A maximum error estimator of the MC became 14% at a MC of 70% and 9% at a MC of 10%. It was therefore concluded that the described method should not be used to estimate the MC of packages after drying but can serve as a valuable indicator of average green MC of a drying batch.

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  • 35.
    Vikberg, Tommy
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad. Luleå University of Technology, Sweden.
    Hägg, Linus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Förädling och processer (TRf).
    Elustondo, Diego
    Luleå University of Technology, Sweden.
    Influence of fan speed on airflow distribution in a batch kiln2015Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 10, nr 2, s. 197-204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study reports experimental data of airflow distribution as a function of fan speed in an industrial batch kiln. Measurements were conducted with 20 hot-film anemometers distributed throughout the load at two occasions. The main result was that airflow distribution did not change significantly as the fan speed was reduced, and no positions where the air movement stopped were found. It was also found that relatively more air ran in the bolster spaces in comparison to the adjacent packages as the air ran through the load.

  • 36.
    Wang, Tianxiang
    et al.
    KTH Royal Institute of Technology, Sweden.
    Wang, Yue
    KTH Royal Institute of Technology, Sweden.
    Crocetti, Roberto
    KTH Royal Institute of Technology, Sweden.
    Wålinder, Magnus
    KTH Royal Institute of Technology, Sweden.
    Bredesen, Ronny
    DYNEA AS, Norway.
    Blomqvist, Lars
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Adhesively bonded joints between spruce glulam and birch plywood for structural applications: experimental studies by using different adhesives and pressing methods2023Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, nr 3, s. 1141-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Due to the increasing interest in reducing the usage of metals in the construction sector, birch plywood has shown good potential in structural engineering and timber connections as a substitute for the more conventional slotted-in metal plate solutions. However, a proper way of bonding birch plywood with other timber parts that results in adequate connection strength has not been fully investigated. In this paper, experimental studies were carried out to investigate the proper workflow when manufacturing bonded connections made of birch plywood and spruce glulam beams. Tensile shear mechanical tests were then conducted on produced bonded joints to evaluate the bond strength. Three adhesives, i.e. melamine-urea-formaldehyde (MUF), phenol–resorcinol–formaldehyde (PRF), and two-component polyurethane (2C PUR) were evaluated in dry and moist conditions. The influence of three pressing methods, i.e. (a) screw-gluing, (b) clamping by means of clamps, and (c) clamping by application of weight loads, on the bonding strength was investigated. The bonding strength was thereafter compared with the shear strength of spruce glulam and the wood failure percentage was also examined in this study. © 2023 The Author(s). 

  • 37.
    Westin, Mats
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Rapp, A.O.
    Nilsson, T
    Field Test of Resistance of Modified Wood to Marine Borers2006Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 1, nr 1, s. 34-38Artikel i tidskrift (Refereegranskat)
  • 38.
    Westin, Mats
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Sterley, Magdalena
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Rossi, Frédéric
    Hervé, Jean-Jérémie
    Compreg-type products by furfurylation during hot-pressing2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 67-75Artikel i tidskrift (Refereegranskat)
  • 39.
    Wålinder, Magnus
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Editorial: The new journal Wood Material Science and Engineering2006Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 1, nr 1, s. 2-3Artikel i tidskrift (Refereegranskat)
  • 40.
    Wålinder, Magnus
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Omidvar, Asghar
    Seltman, Joachim
    Segerholm, Kristoffer
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Micromorphological studies of modified wood using a surface preparation technique based on ultraviolet laser ablation2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 46-51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of this paper is to demonstrate an ultraviolet (UV) laser ablation technique as a tool for sample preparation in microscopy studies of modified wood. Improved techniques for studying the microstructure of modified wood are crucial for a deeper understanding of many of their physical, mechanical and durability properties. The surface preparation technique is described in this paper. An illustration of micrographs of the micromorphology and polymer distribution in some examples of modified wood is also presented. It is clearly demonstrated that in contrast to conventional surface preparation techniques used for light microscopy and scanning electron microscopy, i.e. razor blade and microtome cutting techniques, UV laser ablation does not introduce any mechanically induced microcracks and redistribution of polymers or other mobile substances in the prepared surface. Results also show that, in particular, this technique seems to be suitable for studying polymer distribution in resin-impregnated wood, as well as detection of microcracks in modified wood cell walls.

  • 41.
    Wålinder, Magnus
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Omidvar, Asghar
    Seltman, Joachim
    Segerholm, Kristoffer
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, Trätek.
    Micromorphology Studies of Modified Wood Using a Surface Preparation Technique Based on UV-Laser Ablation2009Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, nr 1-2, s. 46-51Artikel i tidskrift (Refereegranskat)
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