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  • 1.
    Hosseinpourpia, Reza
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Adamopoulos, Stergios
    Mai, Carsten
    Effects of acid pre-treatments on the swelling and vapor sorption of thermally modified Scots pine (Pinus sylvestris L.) wood2018Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, ISSN 1930-2126, Vol. 13, nr 1, 331-345 s.Artikel i tidskrift (Refereegranskat)
  • 2.
    Godinho, Pedro M.J.S.
    et al.
    Vienna University of Technology, Austria.
    Jajcinovic, Marina
    Graz University of Technology, Austria.
    Bader, Thomas K.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Fischer, Wolfgang. J.
    Graz University of Technology, Austria.
    Bauer, Wolfgang
    Graz University of Technology, Austria.
    Hellmich, Christian
    Vienna University of Technology.
    A continuum micromechanics approach to the strength of planar fiber networks: paper material applications2017Ingår i: CompWood 2017 - Computational Methods in Wood Mechanics - From Material Properties to Timber Structures: Programme & Book  of Abstract / [ed] Josef Füssl, Thomas K. Bader, Josef Eberhardsteiner, Vienna: TU verlag , 2017Konferensbidrag (Refereegranskat)
  • 3.
    Scheepers, Gerhard
    et al.
    RISE Research Institutes of Sweden.
    Wiberg, Pär
    Alent Dynamic, Skellefteå.
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    A method to estimate wood surface moisture content during drying2017Ingår i: MADERAS: Ciencia y Tecnología, ISSN 0717-3644, E-ISSN 0718-221X, Vol. 19, nr 2, 133-140 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A method to estimate the surface moisture content below the fibre saturation point that is a function of the surface temperature, wet- and dry bulb temperatures, equilibrium moisture content, and fibre saturation point was evaluated. The method is based on the premise that the surface temperature is solely influenced by the surface moisture content and the climate that the surface is exposed to. The prediction model contends that the surface moisture content is equal to the fibre saturation point when the surface temperature is equal to the wet bulb temperature, and equal to the equilibrium moisture content when the surface temperature is equal to the dry bulb temperature, with a linear interpolation between those two points. The model thus predicts that the average moisture content of a thin piece of veneer can be predicted with fairly good accuracy. Also, when drying boards in a fast changing climate, e.g. fan reversals in industrial kilns, the surface temperature and surface moisture content should change as abruptly as the climate does. Additionally, the surface moisture content should correlate to the known drying phases, with a consistently high surface moisture content during the capillary phase when the wet line is close to the surface, and a quickly decreasing surface moisture content when the wet line moves into the wood during the transition to the diffusion phase. The prediction model was tested in these three scenarios and the results suggest that the basic premise is reasonable, and that the method is useful for surface moisture content estimation.

  • 4.
    Cristina, Simón
    et al.
    Universidad Politécnica de Madrid - Ciudad Universitaria, Spain.
    Francisco, García Fernández
    Universidad Politécnica de Madrid - Ciudad Universitaria, Spain.
    Luis, García Esteban
    Universidad Politécnica de Madrid - Ciudad Universitaria, Spain.
    Paloma, de Palacios
    Universidad Politécnica de Madrid - Ciudad Universitaria, Spain.
    Hosseinpourpia, Reza
    Georg August University Göttingen, Germany.
    Carsten, Mai
    Georg August University Göttingen, Germany.
    Comparison of the saturated salt and dynamic vapor sorption methods in obtaining the sorption properties of Pinus pinea L.2017Ingår i: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 75, nr 6, 919-926 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several methods are available for obtaining the sorption isotherms of wood. Among these, the saturated salt and dynamic vapor sorption methods are the most frequently used  ones. For the first time, the hygroscopic response of wood obtained using these two methods is compared. This is done by determining the 35 and 50°C adsorption isotherms of juvenile and mature wood of Pinus pinea L. The hygroscopic behavior of the two types of wood is different, as the mature wood has a higher moisture content than the juvenile wood in the isotherms studied. Comparison of the static saturated salt method and dynamic vapor sorption shows few significant differences between the equilibrium moisture content obtained by each method during the adsorption process, both in a point by point comparison and in the comparison of quadratic polynomial forms of the Guggenheim Anderson-de Boer model. Moreover, in both methods the point of relative humidity from which multilayer sorption predominates over monolayer sorption is similar.

  • 5.
    Josef, Füssl
    et al.
    Technische Univerität, Austria.
    Bader, Thomas K.Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).Josef, EberhardsteinerTechnische Univerität, Austria.
    CompWood 2017 - Computational Methods in Wood Mechanics - From Material Properties to Timber Structures: Programme & Book of Abstracts2017Proceedings (redaktörskap) (Refereegranskat)
  • 6.
    Hemmilä, Venla
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Karlsson, Olov
    Luleå university of technology.
    Kumar, Anuj
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Development of sustainable bio-adhesives for engineered wood panels – A review2017Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, nr 61, 38604-38630 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Changes in both formaldehyde legislations and voluntary requirements (e.g. Germany RAL) are currently the driving factors behind research on alternatives to amino-based adhesives; moreover, consumer interest in healthy and sustainable products is increasing in bio-based adhesives. Sources of formaldehyde emissions in wood-based panels as well as different emission test methods have been discussed, and the main focus of this review is on the research conducted on sustainable bio-based adhesive systems for wood panels. Lignin, tannin, protein, and starch have been evaluated as both raw materials and adhesive alternatives to existing amino-based thermosetting adhesives. Adhesion improving modifications of these bio-based raw materials as well as the available and experimental crosslinkers have also been taken into account.

  • 7.
    Malmqvist, Cecilia
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Wallin, Elisabeth
    Dalarna University.
    Lindström, Anders
    Dalarna University.
    Säll, Harald
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Differences in bud burst timing and bud freezing tolerance among interior and coastal seed sources of Douglas fir2017Ingår i: Trees, ISSN 0931-1890, E-ISSN 1432-2285, Vol. 31, nr 6, 1987-1998 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The need for species that will grow well through ongoing climate change has increased the interest in Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] in Sweden. One of the most common problems seen in plantations of Douglas fir seedlings is damage caused by late spring frost, known to be highly correlated with the timing of bud burst. The objective of this study was to investigate spring-related bud development under Nordic conditions of seven Douglas fir provenances and to compare data with a local provenance of Norway spruce (Picea abies (L.) Karst). Results from a field trial and a greenhouse-based study were compared. The interior Douglas fir provenances exhibited an earlier bud burst than coastal provenances, both in the greenhouse and in the field trial. When comparing differences within the groups of interior and coastal Douglas fir provenances, no differences could be found. The local Norway spruce, only grown in the greenhouse, showed an intermediate bud development profile similar to the interior Douglas fir provenance Three Valley. We therefore suggest that Three Valley could be planted at the same locations as the investigated local provenance of Norway spruce in mid-Sweden. To avoid spring frost damage the Douglas fir seedlings need to be frozen stored and planted late in spring. Planting under shelterwood can also help protect the seedlings from spring frost damages. As similar results for bud development patterns of Douglas fir and Norway spruce provenances were obtained from the greenhouse and field trials, greenhouse tests could facilitate selection of provenances.

  • 8.
    Landscheidt, Steffen
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Kans, Mirka
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för maskinteknik (MT).
    Winroth, Mats
    Chalmers University of Technology.
    Differences on automation practices in wooden single-family houses manufacturing: Four case studies2017Ingår i: 23rd International Wood Machining Seminar Proceedings / [ed] Marcin Zbiec and Kazimierz Orlowski, Warsaw, Poland: Warsaw University of Life Sciences , 2017, 350-359 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In densely forested countries, forest and wood-based products are an important contributing factor to the country’s economy and also a valuable resource for house manufacturing. With rising demand for housing in Europe, wooden houses have become more of an alternative to concrete houses. Although wooden houses have always been popular in Nordic countries, higher demand puts more pressure on seemingly outdated production facilities and personnel in order to supply the market. Whereas many other industries strive to modern production concepts such as Industry 4.0 to adapt to new market conditions, industrial timber house building is still characterized by a high amount of manual labor.

    In Europe´s highly industrialized countries, labor costs influence wooden house manufacturers rather negatively and exert great pressure on them to stay competitive. Some companies have chosen outsourcing of their operations and production as means to survive. Another way, already successfully proven in other industries, is the automation and digitalization of production processes. Effective implementation of automation equipment depends on several factors, e.g. production volume, applied material, chosen application or cycle times. It is not entirely clear which factors are contributing to the successful change to a more automated production.

    Based on an Industry 4.0 readiness model, the purpose of this study is to seek out which dimensions correlate with each other in order to support improved production processes and efficiency for wooden single-house manufactures. 

    By applying a comparative case study approach, automation standards and practices in Sweden, Germany and Austria, are described and compared. Results of this case study reveal that a production strategy together with sound digital support and information sharing leads to the best production systems for single-wooden houses manufacturers.

  • 9.
    Funk, Monika
    et al.
    Georg-August-University Göttingen, Germany.
    Wimmer, Rupert
    Universität für Bodenkultur Vienna, Austria.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Diotomaceous earth as an inorganic additive to reduce formaldehyde emmissions from particleboards2017Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, nr 2, 92-97 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The presented research is about the use of a new type of a functional inorganic additive in particleboards, for the purpose of reducing free formaldehyde releases. One-layered particleboards were prepared in the laboratory by mixing industrial wood particles and urea-formaldehyde resin. Natural, abundantly and cheaply available nano-mesoporous diatomaceous earth (DE) was used, without and in combination with urea as a scavenger. Silica quartz sand was also added as a nonporous analogy. Particleboards were pressed at two press factors (9 and 15 s/mm). Formaldehyde release was determined using the rapid 3-hour-flask method (DIN EN 717-3). As a result, DE additions insignificantly reduced bending properties of particleboards. Internal bonding was in part significantly lowered. The particleboard produced with 3% urea loaded on 5% DE prior to application almost halved (–45%) the formaldehyde release. Formaldehyde release was on the average 17% lower when pressed at 15 s/mm instead of 9 s/mm. By loading urea onto the nano-mesoporous structure of DE, an improved scavenging function of urea could be shown.

  • 10.
    Blomqvist, Lars
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Nilson, Henrietta
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för organisation och entreprenörskap (OE).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Landscheidt, Steffen
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Downtime causes in a production cell for laminated veneer products2017Ingår i: 23rd International Wood Machining Seminar Proceedings / [ed] Marcin Zbiec and Kazimierz Orlowski, Warsaw, Poland: The Polish Chamber of Commerce of Furniture Manufacturers , 2017, 28-35 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Productivity is often used to determine how well resources are used for an operation. Most often, the ratio of what is produced to what is required to produce it determines productivity. Laminated veneer products are considered complicated products often with complex shapes, a raw material with high variation, and machining processes that create scrap materials that need to be handled. Therefore, keeping a high productivity in the industries producing such products may become challenging. This study reports productivity measurements in a production cell consisting of an adhesive, pressing and processing station. The study seeks to increase understanding of production-related problems in this industry. The research has been using productivity measurement as well as interactive discussions between researchers and workers.

    Measurement of downtime causes were made for 20 days, for a total of approximately 300 hours. The production cell had 1,299 minutes of stops. Of those, 450 minutes were one-time events. The rest were intermittent disturbances. Many of them could be explained by the dust-laden air and processing residues but were also related to veneer and adhesive. There is a need for determining material and processing parameters; however, the first priority is cleaning the factory.

    From a social perspective, some other issues must be added to the discussion of this paper. First and foremost, the business has gone through a transformation from a family business to a privately held firm. From the non-family employee’s view, this is a huge change. This has resulted in unclear roles and responsibilities within the company, which has also affected the productivity of the company.

  • 11.
    Hosseinpourpia, Reza
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). University of Goettingen, Germany.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Holstein, Nonna
    University of Goettingen, Germany.
    Mai, Carsten
    University of Goettingen, Germany.
    Dynamic vapour sorption and water-related properties of thermally modified Scots pine (Pinus sylvestris L.) wood pre-treated with proton acid2017Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 138, 161-168 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the effect of proton acid pre-treatment and subsequent thermal modification at relatively low temperatures (up to 180 °C) on wood with respect to dimensional stability and water vapour sorption properties. The effects are compared to those of solely thermally-modified wood at higher temperatures (up to 250 °C). Scots pine sapwood (P. sylvestris L.) was impregnated with a proton acid or demineralised water, and subsequently, thermally modified to various mass losses (ML). Acid pre-treatment and thermal modification improved the dimensional stability and reduced the equilibrium moisture content (EMC) until certain ML. Excess surface work (ESW) obtained from vapour sorption studies indicated that, at comparable ML, the acid pre-treatment reduced the available sorption sites as compared to sole thermal treatment. Samples pre-treated with acid also showed stronger decreasing courses of EMC- and ESW-ratios than sole thermally modified ones. This was attributed to degradation of amorphous wood polymers and a stiffer matrix due to cross-linking of the cell wall polymers as a consequence of acid pre-treatment. Electron spin resonance (ESR) analysis indicated that acid pre-treatment did not enhance the concentration of phenoxy radicals, whereas thermally modified wood showed a considerably higher concentration of phenoxy radicals, suggesting that high radical density cannot be used as an indicator for high matrix stiffness.

  • 12.
    Ahmed, Sheikh Ali
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Morén, Tom
    Luleå University of Technology.
    Sehlstedt-Persson, Margot
    Luleå University of Technology.
    Blom, Åsa
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Effect of oil impregnation on water repellency, dimensional stability and mold susceptibility of thermally-modified European aspen and downy birch wood2017Ingår i: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 63, nr 1, 74-82 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Conventional chemical wood preservatives have been banned or restricted in some applications due to human and animal toxicity and their adverse impact on the surrounding environment. New, low-environmental-impact wood treatments that still provide effective protection systems are needed to protect wood. Thermal modification of wood could reduce hygroscopicity, improve dimensional stability and enhance resistance to mold attack. The aim of this study was to investigate if these properties enhanced in thermally modified (TM) wood through treatments with oils. In this study, TM European aspen (Populus tremula) and downy birch (Betula pubescens) wood were impregnated with three different types of oil: water-miscible commercial Elit Träskydd (Beckers oil with propiconazole and 3-iodo-2-propynyl butylcarbamate, IPBC), a pine tar formulation and 100% tung oil. The properties of oil-impregnated wood investigated were water repellency, dimensional stability and mold susceptibility. The treated wood, especially with pine tar and tung oil, showed an increase in water repellency and dimensional stability. However, Beckers oil which contains biocides like propiconazole and IPBC showed better protection against mold compared with pine tar and tung oil. To enhance the dimensional stability of the wood, pine tar and tung oil can be used, but these oil treatments did not significantly improve mold resistance rather sometimes enhanced the mold growth, whereas a significant anti-mold effect was observed on Beckers oil treated samples.

  • 13.
    Bastani, Alireza
    et al.
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Militz, Holger
    Georg-August-University Göttingen, Germany.
    Effect of open assembly time and equilibrium moisture content on the penetration of polyurethane adhesive into thermally modified wood2017Ingår i: The journal of adhesion, ISSN 0021-8464, E-ISSN 1563-518X, Vol. 93, nr 7, 575-583 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of wood moisture content and open assembly time on penetration of polyurethane (PU) adhesive into thermally treated Scots pine (195 and 210°C) was investigated according to effective (EP) and maximum penetration (MP) measurements using fluorescence microscopy. For samples treated at 195°C, a higher EP was noted at 8.6% equilibrium moisture content (EMC) after both assembly times (15 and 30 min) while for samples treated at 210°C, increasing wood moisture content resulted in a significant decrease in EP at 12.5% EMC after 15 min assembly time. Extending open assembly time was found to increase the EP of PU adhesive only in the case of samples treated at 195°C and with 8.6% EMC. For samples treated at both treatment temperatures and after shorter open assembly time, the highest MP observed at moderate EMC levels of 8.6 and 8.2% and the lowest at the higher EMC levels of 13.2 and 12.5%.

  • 14.
    Trischler, Johann
    et al.
    Luleå University of Technology.
    Sandberg, Dick
    Luleå University of Technology.
    Dorn, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Effect of temperature during vital gluten adhesive preparation and application on shear-bond strength2017Ingår i: Journal of Adhesion Science and Technology, ISSN 0169-4243, E-ISSN 1568-5616, Vol. 32, nr 4, 448-455 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    If protein-based adhesives are to become a competitive bio-based alternative to synthetic adhesives, the preparation and application methods have to be considerable improved to reduce process time and thereby improve the economy of the adhesive system. The purpose of this study was to investigate the impact of the temperature during preparation and application on the shear-bond strength of an adhesive based on vital gluten for use in wood applications. Vital gluten was used in its natural form and mixed with water of different temperatures (preparation temperature 0 °C or 20 °C), and applied on beech veneer at different temperature (application temperature –10, 20, 60 and 100 °C). Tensile shear-bond strength samples were prepared and tested according to EN 205. The results showed that an increase in veneer temperature during application of the adhesive led to a decrease in the shear-bond strength, but that the preparation temperature of the adhesive had no influence on the strength.

  • 15.
    Jensen, Anna M.
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Löf, Magnus
    Swedish University of Agricultural Sciences.
    Effects of interspecific competition from surrounding vegetation on mortality, growth and stem development in young oaks (Quercus robur)2017Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 392, 176-183 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Facilitation by a neighboring woody understory has been suggested as a cost-effective and sustainable way to regenerate oaks. However, concerns about reduced plant growth and quality due to competing neighboring vegetation have hindered implementation. Here we studied competitive effects from herbaceous and woody vegetation on survival, growth, canopy development and stem quality in pedunculate oak (Quercus robur) in an open-field experiment in southern Sweden. Oaks were grown for eight years in four different competition treatments: no competing vegetation, with herbaceous vegetation (mainly grasses), with woody vegetation, and with both herbaceous and woody vegetation. During the first four years, competition had little effect on oak survival. However, after eight growing seasons, survival rates decreased to about 20% for oaks surrounded by woody vegetation, in contrast to oaks grown with only herbaceous vegetation that had a survival rate of near 100%. Competition from herbaceous and woody vegetation both reduced oak stem diameter and height growth, but they affected height growth differently. During the first growing seasons, oaks in the treatment with woody vegetation were able to keep up with the height growth of the surrounding vegetation. Thereafter, height growth stagnated, and after eight growing seasons heights of oaks in the treatment with woody competitors were only 30–39% that of oaks in the treatment without competing vegetation. In contrast, competition from herbaceous vegetation only restricted oak height development marginally. Interspecific competition not only restricted growth and survival but also shifted shoot architecture, resulting in a greater frequency of oaks with straight monopodial stems. Although competition from both herbaceous- and woody vegetation positively affected stem straightness, plots with woody vegetation had a greater proportion (0.42) of oaks with a single straight monopodial stem. Our results demonstrate that the facilitative competitive effects from herbaceous and woody vegetation could be used to control allocation patterns in young oaks, promoting development of tall straight monopodial stems. Considering the observed trade-off between high stem quality and survival, we recommend long-term assessment of this trade-off prior to application in practical forestry.

  • 16.
    Ormarsson, Sigurdur
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Johansson, Marie
    SP.
    FE-modell av en volymmodul - spännings- och stabilitetsanalys : Förstudie2017Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Trä är ett mycket användbart, prisvärt och förnyelsebart material som rätt utnyttjat har en extremt hög industriell potential inom området byggnadskonstruktion. Det finns ett stort intresse i Sverige att utforska nya sätt att utnyttja trä som huvudlastbärande material i olika typer av flervåningshus. Detta är en stor utmaning för träbyggnadsindustrin, forskare och konstruktörer eftersom det inte finns någon traditionell beräknings- och designprocedur för dessa typer av byggnader.

    I denna förstudie har en parametrisk FE-modell framtagits för att studera strukturmekaniska egenskaper (deformationer och styvhet) hos en typisk volymmodul som används för byggande av flerbostadshus i trä. Modellen är uppbyggd av olika typer av strukturelement (fjädrar, balk- och skalelement) för att den skall vara så snabb och flexibel som möjligt. Modellen inkluderar ett stort antal konnektor- och kopplingselement för att på ett optimalt sätt kunna simulera alla spik-, skruv- och bultförband i modulen. Modellen är också ganska flexibel eftersom den är parameterstyrd via ett antal geometriska parametrar. Modellen har använts för att studera globala deformationer och styvhetsegenskaper hos olika vägg- och volymelement när de belastas med olika mekaniska laster. Att få en uppfattning om hur styvhetsegenskaper hos de mekaniska förbanden (svaga delar i konstruktionen) påverkar det globala deformationsbeteendet hos olika vägg- och volymelement har varit en viktig del i denna förstudie.

    Modellen visar ett deformationsbeteende hos vägg- och volymelementen verkar rimliga men en experimentell verifiering återstår. Ett exempel på resultat är att väggelement som belastas i planskjuvning har en tydlig tendens att böja ut ur planet eftersom det finns gipsskiva enbart på insidan av regelstommen. Studien visar också att för volymmoduler med en gles skruvförbindning mellan vägg- och bjälklagselementen uppkommer stora gliddeformationer mellan elementen. En av de viktigaste slutsatser från denna förstudie är att det gick att skapa en snabb och effektiv strukturmekanisk tredimensionell FE-modell för den här typen av konstruktion. Beräkningstiden för en volymmodul var endast 5.5 minuter på en vanlig laptop computer. Dessa resultat visar därför att det finns goda förutsättningar för att kunna simulera och analysera hela flerbostadshus inom rimliga beräkningstider.

  • 17.
    Norby, Richard J.
    et al.
    Oak Ridge National Laboratory, USA.
    Gu, Lianhong
    Oak Ridge National Laboratory, USA.
    Haworth, Ivan C.
    Oak Ridge National Laboratory, USA.
    Jensen, Anna M.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Oak Ridge National Laboratory, USA.
    Turner, Benjamin L.
    Smithsonian Tropical Research Institute, Panama.
    Walker, Anthony P.
    Oak Ridge National Laboratory, USA.
    Warren, Jeffrey M.
    Oak Ridge National Laboratory, USA.
    Weston, David J.
    Oak Ridge National Laboratory, USA.
    Xu, Chonggang
    Los Alamos National Laboratory, USA.
    Winter, Klaus
    Smithsonian Tropical Research Institute, Panama.
    Informing models through empirical relationships between foliar phosphorus, nitrogen and photosynthesis across diverse woody species in tropical forests of Panama2017Ingår i: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 215, nr 4, 1425-1437 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Our objective was to analyze and summarize data describing photosynthetic parameters and foliar nutrient concentrations from tropical forests in Panama to inform model representation of phosphorus (P) limitation of tropical forest productivity.

    Gas exchange and nutrient content data were collected from 144 observations of upper canopy leaves from at least 65 species at two forest sites in Panama, differing in species composition, rainfall and soil fertility. Photosynthetic parameters were derived from analysis of assimilation rate vs internal CO2 concentration curves (A/Ci), and relationships with foliar nitrogen (N) and P content were developed.

    The relationships between area-based photosynthetic parameters and nutrients were of similar strength for N and P and robust across diverse species and site conditions. The strongest relationship expressed maximum electron transport rate (Jmax) as a multivariate function of both N and P, and this relationship was improved with the inclusion of independent data on wood density.

    Models that estimate photosynthesis from foliar N would be improved only modestly by including additional data on foliar P, but doing so may increase the capability of models to predict future conditions in P-limited tropical forests, especially when combined with data on edaphic conditions and other environmental drivers.

  • 18.
    Bader, Thomas K.
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Vessby, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Modeling displacement path dependence in nailed sheathing-to-framing connections2017Ingår i: CompWood 2017 - Computational Methods in Wood Mechanics - from Material Properties to Timber Structures: Programme & Books of Abstracs / [ed] Josef Füssl, Thomas K. Bader, Josef Eberhardsteiner, Vienna: TU verlag , 2017Konferensbidrag (Refereegranskat)
  • 19.
    Nilsson, Jonaz
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Ormarsson, Sigurdur
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Moisture-related distortion and damage of lightweight wood panels: experimental and numerical study2017Ingår i: Journal of the Indian Academy of Wood Science, ISSN 0972-172XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study was conducted to increase the knowledge of moisture-related distortion and damage in the field of wood-based lightweight panels. By increasing the possibilities of predicting moisture-related distortion and damage, the possibilities of using lightweight wood materials could increase. The study was performed through experiments and modelling work on a wooden panel product with numerous struts and two thin outer-face sheets of beech-wood glued tightly onto the struts, as well as reference panels of solid wood. During the testing period the results showed the density of the studied lightweight panels to vary from 170 to 290 kg/m3. These panels shrunk and swelled less than the solid wood panels and reacted faster to changes of surrounding humidity and temperature. Moisture related distortions such as twist and bow were not inferior compared to the solid wood panels. Shrinkage or swelling produced moisture related stresses. This may mean that the panel will have a risk of serious damage in the form of cracks or glue release between the outer face sheet and the struts when it is exposed to intense drying. The experimental tests also followed how various damages arose in the panels. Until the damage occurred, the deformation results showed a strong agreement between the experimental and the model findings. Better knowledge of how this type of panel reacts to climate variations is important for the further design and development of this type of product.

  • 20.
    Bader, Thomas K.
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Bocquet, Jean-Francois
    University of Lorraine, France.
    Schweigler, Michael
    Vienna University of Technology, Austria.
    Lemaitre, Romain
    University of Lorraine, France.
    Numerical modeling of the load distribution in multiple fastener joints2017Ingår i: International Conference on Connections in Timber Engineering – From Research to Standards: Proceedings of the Conference of COST Action FP1402 at Graz University of Technology / [ed] Reinhard Brandner, Andreas Ringhofer & Philipp Dietsch, Graz: Verlag der Technischen Universität Graz , 2017, 136-152 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Numerical modeling approaches, for the determination of load distribution in laterally loaded joints, as well as for the assignment of stiffness properties of joints for the structural analysis, are summarized in this contribution. The effect of the nonlinearity and the load-to-grain orientation dependence of connection slip, of elastic deformation in the surrounding wood matrix, and of the deviation between load and displacement direction are discussed. Comparison of various models demonstrates the pronounced effect of the load-to-grain orientation dependence and the nonlinearity in connection slip on the load distribution, particularly in case of moment loading. The effect of elastic deformation in the wood matrix on the load distribution increases with increased size of joints, even more pronounced when joints are loaded by a shear force perpendicular to the grain. In case of normal force loading, the non-uniform load distribution due to elastic deformation in the wood matrix reduces rapidly with increased relative joint displacement. Pros and cons of the modeling approaches as well as necessary input data are discussed in relation to the design process and European standardization.

  • 21.
    Ormarsson, Sigurdur
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Johansson, M.
    Numerical simulations of structural behaviour of volume modules used for construction of multifamily timber houses2017Ingår i: CompWood 2017 : Computational Methods in Wood Mechanics – from Material Properties to Timber: Programme & Book of abstract, 2017Konferensbidrag (Refereegranskat)
  • 22.
    Landscheidt, Steffen
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Kans, Mirka
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för maskinteknik (MT).
    Winroth, Mats
    Chalmers University of Technology.
    Opportunities for robotic automation in wood product industries: The supplier and system integrators´ perspective2017Ingår i: Procedia Manufacturing, ISSN 1873-6580, E-ISSN 2212-0173, Vol. 11, 233-240 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the opportunities for automation in the poorly automated wood product industry are highlighted. This isaccomplished by conducting a qualitative interview study of suppliers and system integrators for industrial robots active in thisparticular industry sector. Five case companies are chosen in order to explore the unique dimensions responsible for successfulautomation implantation in wood product companies. Results show that a low understanding of automation opportunities, unclearrequirements specifications, and small production volumes are the main problems for suitable automation solutions. Althoughwood is a fragile and changeable material, existing technology allows its manipulation with industrial robots.

  • 23.
    Hedwall, Per-Ola
    et al.
    Swedish University of Agricultural Science.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Brunet, Jorg
    Swedish University of Agricultural Science.
    Phosphorus and nitrogen co-limitation of forest ground vegetation under elevated anthropogenic nitrogen deposition2017Ingår i: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 185, nr 2, 317-326 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plant growth in northern forest ecosystems is considered to be primarily nitrogen limited. Nitrogen deposition is predicted to change this towards co-limitation/limitation by other nutrients (e.g., phosphorus), although evidence of such stoichiometric effects is scarce. We utilized two forest fertilization experiments in southern Sweden to analyze single and combined effects of nitrogen and phosphorus on the productivity, composition, and diversity of the ground vegetation. Our results indicate that the productivity of forest ground vegetation in southern Sweden is co-limited by nitrogen and phosphorus. Additionally, the combined effect of nitrogen and phosphorus on the productivity was larger than when applied solely. No effects on species richness of any of these two nutrients were observed when applied separately, while applied in combination, they increased species richness and changed species composition, mainly by promoting more mesotrophic species. All these effects, however, occurred only for the vascular plants and not for bryophytes. The tree layer in a forest has a profound impact on the productivity and diversity of the ground vegetation by competing for both light and nutrients. This was confirmed in our study where a combination of nitrogen and high tree basal area reduced cover of the ground vegetation compared to all the other treatments where basal area was lower after stand thinning. During the past decades, nitrogen deposition may have further increased this competition from the trees for phosphorus and gradually reduced ground vegetation diversity. Phosphorus limitation induced by nitrogen deposition may, thus, contribute to ongoing changes in forest ground vegetation.

  • 24.
    Malmqvist, Cecilia
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Planting and survivability of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) in Sweden: Questions of seedling storability, site preparation, bud burst timing and freezing tolerance2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The non-native Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) has been grown to a limited extent in the southern part of Sweden since the early 1900s. A more extensive use has probably been curtailed by its known susceptibility to damage by frost, pine weevil and other pests. Limited access to vital seedlings of suitable provenances has also restricted its more widespread growth. The need for valuable species that will grow well through ongoing climate change has increased the interest for Douglas fir in Sweden.

    This thesis addresses a number of important questions relating to the planting of Douglas fir in Sweden: seedling storability, freezing tolerance, timing of bud burst, frost damage and seedling response to site preparation. Seven Douglas fir provenances originating from British Columbia, Canada were used in the experiments and where applicable, compared with a local provenance of Norway spruce (Picea abies (L.) Karst.). The early bud burst of interior Douglas fir provenances, observed both in greenhouse tests and in the field, results in a high risk of damage by late spring frost. This type of damage does not seem, however, to be fatal and does not obviously retard the early growth of seedlings. The difference in growth between coastal and interior provenances was insignificant, but survival was greater for interior than for coastal provenances. All the provenances of Douglas fir studied showed a later development of freezing tolerance of shoots and roots in the autumn than Norway spruce, with the coastal provenances developing such tolerance even later than interior provenances. This could be a contributory cause for the severe damage by winter desiccation observed on seedlings of coastal origin. A thorough site preparation proved to be an effective way to increase survival and root growth. Interior provenances of Douglas fir became ready for storage earlier in autumn than coastal provenances. When freezing tolerance of shoots had increased sufficiently, Douglas fir seedlings could safely be kept in frozen storage using the same procedures used for Norway spruce. The results emphasise the need to gain further knowledge about how the remaining obstacles to establishment of Douglas fir could be reduced with different silviculture methods.

  • 25.
    Bader, Thomas K.
    et al.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    de Borst, Karin
    University of Glasgow, UK.
    Shear stiffness and its relation to the microstructure of 10 European and tropical hardwood species2017Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, nr 2, 82-91 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, shear stiffness properties of 10 different hardwood species and their relation to the corresponding species-specific microstructure are investigated. For this purpose, shear stiffness of 10 different hardwood species is experimentally measured by means of ultrasonic testing. In addition, a micromechanical model for hardwood is applied in order to illustrate the influence of certain microstructural characteristics such as mass density and volume fractions of vessels and ray cells on the shear stiffness. Comprehensive microstructural and mechanical data from previous investigations of the same hardwood material support the interpretation of the microstructure–shear stiffness relationships. Mass density was confirmed to be the dominant microstructural characteristic for shear stiffness. Also, ultrasound shear wave propagation velocity increases with density, particularly in the radial-tangential (RT) plane. In addition to density, comparably higher shear stiffness GLR can be explained by comparably higher ray content and lower vessel content. As for GLT, a ring porous structure seems to lead to higher shear stiffness as compared to a diffuse porous structure. For this shear stiffness, vessel and ray content were found to have a less impact. Also, the rolling shear stiffness GRT was found to be higher for a diffuse porous structure than for a ring porous one. Moreover, the data supports that ray cells act as reinforcements in the RT plane and lead to higher GRT

  • 26.
    Bastani, Alireza
    et al.
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Militz, Holger
    Georg-August-University Göttingen, Germany.
    Shear strength of furfurylated, N-methylol melamine and thermally modified wood bonded with three conventional adhesives2017Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, nr 4, 236-241 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The shear strength of furfurylated, N-methylol melamine (NMM) and thermally modified wood bonded with emulsion polymer isocyanate, polyvinyl acetate (PVAc), and polyurethane (PU) adhesives was examined. Furfurylation and NMM modification of Scots pine had a significant negative effect on the bonding strength with all adhesives irrespective of the treatment intensity. The obtained low-shear strength values were related to the brittle nature of the wood after modifications rather to the failure of the bondline. PVAc showed a better bonding performance with both furfurylated and NMM modified wood while the combination of furfurylated wood and PU gave the highest reduction in bonding strength (47–51%). Shear strength also decreased significantly after thermal modification in both Scots pine (36–56%) and beech (34–48%) with all adhesives. With the exception of thermally modified beech samples bonded with PU, bondline was found to be the weakest link in thermally modified wood as it was revealed by the wood failure surfaces. Bondline thickness and effective penetration of adhesives did not relate to the shear strength of all modified wood materials. The lower shear strength of modified wood could be attributed to other factors, such as the reduced chemical bonding or mechanical interlocking of adhesives, and the reduced strength of brittle modified wood substrate.

  • 27.
    Malmqvist, Cecilia
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Wallertz, Kristina
    Swedish University of Agricultural Sciences.
    Lindström, Anders
    Dalarna University ; Swedish University of Agricultural Sciences.
    Storability and freezing tolerance of Douglas fir and Norway spruce seedlings grown in mid-Sweden2017Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 32, nr 1, 30-38 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Climate change provides new challenges to Nordic forestry. Use of non-native species, such as Douglas fir, can be a means of mitigating the effects of climate change and meeting the growing demand for biomass. When Douglas fir is grown in Sweden, it is several degrees of latitude north of its normal range, which can affect timing of growth cessation, hardening of seedlings, and seedling storability. The objective of this study was to investigate tolerance to freezing and sub-zero storability of seven Douglas fir provenances and make comparisons with the native Norway spruce. Freezing tolerance and storability were evaluated by measuring the electrolytic leakage of shoots and roots after freezing, complemented with a three-week cultivation test after storage. All provenances of Douglas fir used in this study were able to tolerate frozen storage at −4°C for about four months. Norway spruce and the interior Douglas fir provenance, Three Valley, could be stored earlier in the autumn than the southern coastal Douglas fir provenances. Consequently, it should be possible to store Douglas fir seedlings with the same routines as for Norway spruce.

  • 28.
    Hochreiner, Georg
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Schweigler, Michael
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Structural behaviour and design of dowel groups: experimental and numerical identification of stress states and failure mechanisms of the surrounding timber matrix2017Ingår i: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 131, 421-437 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dowel-type fasteners in combination with steel plates are widely used in engineered timber structures. Since dowel groups are designed as semi-rigid connections subjected to an arbitrary set of internal forces, the corresponding structural behaviour of the surrounding timber matrix must be considered in the design process accordingly, including the effect of reinforcements. Corresponding stress states and failure mechanisms in the timber matrix of dowel groups are discussed herein. Surface strain fields from tests of dowel groups under complex loading situations were used to identify the sequence of cracking, as well as to assign the related failure modes. First cracking events were caused by stress peaks at the most loaded dowels and by a combination of shear stresses and stresses perpendicular to the grain, while later crack- ing events were associated with a predominant action of individual stress components. Thus, the non- linear global moment-relative rotation behaviour of dowel groups could be related to failure mechanisms in the surrounding timber matrix. The corresponding strain state was qualitatively as well as quantita- tively reproduced by means of a numerical model, which gave access to stresses in the timber matrix and has potential to be implemented as a sub-model in engineering design software. The numerical model supported the feasibility of a decomposition of the stress state due to the global bending moment into stresses caused by a couple of equal forces parallel and perpendicular to the grain, which could be used in the design process. Based on experimental and numerical findings, essential aspects for a design procedure for the timber matrix in dowel groups loaded by a combination of internal forces are proposed. 

  • 29.
    Kumar, Anuj
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Czech Technical University in Prague, Czech Republic.
    RIchter, Jan
    Czech Technical University in Prague, Czech Republic.
    Tywoniak, Jan
    Czech Technical University in Prague, Czech Republic.
    Hajek, Petr
    Czech Technical University in Prague, Czech Republic.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Šegedin, Urban
    University of Ljublijana, Slovenia.
    Marko, Petrič
    University of Ljublijana, Slovenia.
    Surface modification of Norway spruce wood by octadecyltrichlorosilane (OTS) nanosol by dipping and water vapour diffusion properties of the OTS-modified wood2017Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present research deals with a simple dipping method to insert octadecyltrichlorosilane (OTS) into cell walls of spruce wood and to deposit OTS layers on its inner and outer surfaces. Distribution and chemical interactions of OTS with wood polymers has been investigated by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The OTS/n-hexane solution penetrated into wood via capillary forces through ray tracheids and bordered pits and was deposited as OTS organic-inorganic layers on wood cell walls. The hypothesis is supported by the results, according to which the OTS molecules are hydrolysed by the wood moisture and by free OH groups of the cell wall components. The hydrolysed OTS molecules react with the OH groups and elevate the hydrophobicity of wood.

  • 30.
    Cintas, Olivia
    et al.
    Chalmers University of Technology.
    Berndes, Göran
    Chalmers University of Technology.
    Hansson, Julia
    Chalmers University of Technology ; IVL Swedish Environmental Research Institute.
    Poudel, Bishnu Chandra
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Börjesson, Pål
    Lund University.
    Egnell, Gustaf
    Swedish University of Agricultural Sciences.
    Lundmark, Tomas
    Swedish University of Agricultural Sciences.
    Nordin, Annika
    Swedish University of Agricultural Sciences.
    The potential role of forest management in Swedish scenarios towards climate neutrality by mid century2017Ingår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 383, nr Special Issue, 73-84 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Swedish climate policy targets net zero greenhouse gases (GHG) by mid-century, with road transport independent of fossil fuels by 2030, requiring far-reaching changes in the way energy is used. Forest management is expected to support carbon sequestration and provide biomass for various uses, including energy. In this paper, we combine two energy scenarios with four forest scenarios and quantify GHG balances associated with energy-use for heat, electricity, and road transport, and with forest management and production, use, and end-of-life management of various forest products, including products for export. The aggregated GHG balances are evaluated in relation to the 2-degree target and an allocated Swedish CO2 budget. The production of biofuels in the agriculture sector is considered but not analyzed in detail.

    The results suggest that Swedish forestry can make an important contribution by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The GHG neutrality goal is not met in any of the scenarios without factoring in carbon sequestration. Measures to enhance forest productivity can increase output of forest products (including biofuels for export) and also enhance carbon sequestration. The Swedish forest sector can let Sweden reach net negative emissions, and avoid “using up” its allocated CO2 budget, thereby increasing the associated emissions space for the rest of the world.

  • 31.
    Altgen, Michael
    et al.
    Georg-August University, Germany.
    Adamopoulos, Stergios
    Georg-August University, Germany.
    Militz, Holger
    Georg-August University, Germany.
    Wood defects during industrial-scale production of thermally modified Norway spruce and Scots pine2017Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, nr 1, 14-23 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This research investigates wood defects, particularly the formation of surface cracks, during the production of thermally modified wood and its exposure to cyclic moisture changes. Boards of Norway spruce and Scots pine originating from different steps within the production of ThermoWood® were collected and wood defects were investigated at macroscopic and microscopic scale. Subsequently, the wood was exposed to capillary wetting cycles to record its sensitivity towards cracking. After the modification process, typical anatomical defects of conventional kiln-drying became more frequent and severe, with the magnitude being to some extent depending on the presence of defects in the raw material. At microscopic scale, damages to ray parenchyma and epithelial cells as well as longitudinal cracks within the cell walls of earlywood tracheids were evident in thermally modified wood. Despite a lower water uptake and higher dimensional stability, thermally modified wood was more sensitive to surface cracking during wetting cycles than unmodified wood, i.e. at the outside face of outer boards (near bark). For limiting surface cracking of thermally modified wood during service life, the use of high-quality raw material, the exposure of the inside face of the boards (near pith) and the application of a surface coating are considered beneficial.

  • 32.
    Adamopoulos, Stergios
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Karastergiou, Sotirios
    Technological Educational Institute of Thessaly, Greece.
    Foti, Dafni
    Aristotle University, Greece.
    Filippou, Vasileios
    Aristotle University, Greece.
    ΑΝΑΚΤΗΣΗ ΞΥΛΟΤΕΜΑΧΙΔΙΩΝ ΑΠΟ ΑΠΟΣΥΡΟΜΕΝΕΣ ΜΟΡΙΟΠΛΑΚΕΣ ΜΕ ΥΔΡΟ-ΜΗΧΑΝΙΚΕΣ ΜΕΘΟΔΟΥΣ: [ Chips recovered from waste particleboards by hydro-mechanical methods ]2017Ingår i: ΠΡΑȀΤǿȀΑ : 18ου Πανελλήνιου Δασολογικού Συνεδρίου : “Η Ελληνική Δασοπονία μπροστά σε σημαντικές προκλήσεις: αειφορική διαχείριση δασών, δασικοί χάρτες, περιβαλλοντικές τεχνολογίες – δικτύωση και προστασία φυσικού περιβάλλοντος”: & International Workshop : “Information Technology, Sustainable Development, Scientific Network & Nature Protection” : 8-11 Οκτωβρίου 2017, ΕΔΕΣΣΑ ΠΕȁȁΑΣ, Περιοχή Βαρόσι, Hellenic Forestry Society , 2017, 349-356 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    It was studied the recovery of wood chips from waste particleboards by immersion in water at ambient temperature and by mechanical treatment (agitation and impact, waterblasting). Four different categories of waste particleboards were used, with and without coating, after their reduction in smaller pieces with dimensions of about 7 × 8 cm.  The investigated methods were: (I) immersion for 3 days-impregnation with vacuum and pressure-agitation and impact (II) immersion for 7 days-drying-rewetting for 12 hours-agitation and impact (III) immersion for 3 days-waterblasting. The maximum thickness swelling (about 90%) was achieved by immersing the particleboards in the water for 3 days, and therefore the vacuum and pressure impregnation step can be omitted in practice. Recovery of wood chips was significantly higher (51.54%) in the case of successive wetting and drying cycles compared to simple immersion in water (17.32%). Both these methods I and II, involving agitation and impact for recovering wood chips from waste particleboards, are easily applicable at the industry. Method III with waterblasting resulted in complete recovery of wood chips within a very short time, but its application requires more research

  • 33.
    Voulgaridis, Elias
    et al.
    Aristotle University, Greece.
    Passialis, Costas
    Aristotle University, Greece.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Foti, Dafni
    Aristotle University, Greece.
    Voulgaridou, Eleni
    Aristotle University, Greece.
    ΠΑΡΑΓΩΓΗ ΚΑΙ ΙΔΙΟΤΗΤΕΣ ΠΕΙΡΑΜΑΤΙΚΩΝ ΠΛΙΝΘΩΝ ΕΣΩΤΕΡΙΚΗΣ ΤΟΙΧΟΠΟΙΙΑΣ ΑΠΟ ΓΥΨΟ ΚΑΙ ΑΝΑΚΥΚΛΟΥΜΕΝΑ ΥΛΙΚΑ ΞΥΛΟΥ ΚΑΙ ΕΛΑΣΤΙΚΩΝ ΟΧΗΜΑΤΩΝ: [ Production and properties of experimental bricks for interior walls from gypsum and recycled materials of wood and rubber ]2017Ingår i: ΠΡΑȀΤǿȀΑ : 18ου Πανελλήνιου Δασολογικού Συνεδρίου : “Η Ελληνική Δασοπονία μπροστά σε σημαντικές προκλήσεις: αειφορική διαχείριση δασών, δασικοί χάρτες, περιβαλλοντικές τεχνολογίες – δικτύωση και προστασία φυσικού περιβάλλοντος”: & International Workshop : “Information Technology, Sustainable Development, Scientific Network & Nature Protection” : 8-11 Οκτωβρίου 2017, ΕΔΕΣΣΑ ΠΕȁȁΑΣ, Περιοχή Βαρόσι, Hellenic Forestry Society , 2017, 315-323 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Τhe manufacturing and testing of gypsum bonded solid bricks with wood chips from particleboard production residues and rubber and textile fibers from waste tires was investigated. The recovered rubber and wood materials were mixed in gypsum/water solutions for the fabrication of standard solid bricks with six holes by using appropriate molds. After drying, the compressive strength, the thermal conductivity, the air-flow resistance, the sound absorption coefficient and the emissions of volatile organic compounds (VOC) of the bricks were determined. The compressive strength of solid bricks was much greater than that required in interior walls. The bricks showed a better thermal insulation than both the extruded and pressed house bricks but lower than the insulating bricks. Emissions of volatile organic compounds of bricks were at acceptable levels according to regulations for construction products. The sound absorption coefficient of the solid bricks was 0,72 for the frequency of 1 kHz and decreased with increasing frequency. In addition, information on the raw materials and production cost are given.

  • 34.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    A laser drilling technique to improve impregnability of spruce and fir2016Ingår i: 3rd BASF Wolman Conference, 14 September 2016, Linnaeus University, Växjö, Sweden, 2016Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 35.
    Schweigler, Michael
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Hochreiner, Georg
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    A Novel Approach for the Load-Displacement Behavior of Single-Dowel Connections in Laminated Veneer Lumber2016Ingår i: 17th International Conference on Experimental Mechanics, Rhodes, Greece, July 3-7, 2016, 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The load-to-grain orientation dependence of the mechanical behavior of single-dowel connections is discussed in this contribution. The effect of the anisotropy of wood was experimentally assessed by means of a novel biaxial test set-up. Thus, lateral reaction forces in addition to forces parallel to the prescribed displacement direction could be quantified. Material properties of the components, namely the steel dowel and the Laminated Veneer Lumber were measured as well. This comprehensive experimental dataset was further exploited in an engineering model for single-dowel connections.

  • 36.
    Subramanian, Narayanan
    et al.
    Swedish University of Agricultural Sciences.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Ulf
    Swedish University of Agricultural Sciences.
    Nilsson, Urban
    Swedish University of Agricultural Sciences.
    Sallnäs, Ola
    Swedish University of Agricultural Sciences.
    Adaptation of Forest Management Regimes in Southern Sweden to Increased Risks Associated with Climate Change2016Ingår i: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 7, nr 1, 8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Even though the growth rates of most tree species in Sweden is expected to increase in the near future as a result of climate change, increased risks of damage by storms and various pests and pathogens, notably root rot and bark beetles, may also occur. Thus, forest management practices such as changes to thinning regimes, reductions in rotation lengths, and switching to other species (native or exotic) may represent adaptive management strategies to increase the resistance and resilience of Swedish forests to climate change. Clearly, thorough analyses examining the effects of anticipated climatic changes on damage levels, and the potentially relieving effects of possible management adaptations are needed before implementing such changes. In this study, damage caused by storms, root rot and bark beetles (single and in various combinations) under selected climate and management scenarios were simulated in Norway spruce (Pice abies L. Karst) stands. The results indicate that reductions in thinning intensity and rotation lengths could improve both volume production and profitability in southern Sweden. In addition, cultivation of rapidly growing species, such as hybrid larch (Larix × marschlinsii Coaz.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.), could be as profitable as Norway spruce cultivation, or even more profitable. However, slow-growing species, such as Silver birch (Betula pendula Roth), Downy birch (Betula pubescens Ehrh.) and European beech (Fagus sylvatica L.) indicated low economic output in terms of Land Expectation Value.

  • 37.
    Keskitalo, E. Carina H.
    et al.
    Umeå University.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Felton, Adam
    Swedish University of Agricultural Sciences.
    Björkman, Christer
    Swedish University of Agricultural Sciences.
    Berlin, Mats
    Uppsala Science Park.
    Axelsson, Petter
    Swedish University of Agricultural Sciences.
    Ring, Eva
    Uppsala Science Park.
    Agren, Anneli
    Swedish University of Agricultural Sciences.
    Roberge, Jean-Michel
    Swedish University of Agricultural Sciences.
    Klapwijk, Maartje J.
    Swedish University of Agricultural Sciences.
    Boberg, Johanna
    Swedish University of Agricultural Sciences.
    Adaptation to Climate Change in Swedish Forestry2016Ingår i: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 7, nr 2, 28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adaptation to climate change in forestry has become a growing concern, in part due to the impact of storms and other events that have raised the awareness of such risks amongst forest owners. Sweden is one of Europe's most densely-forested countries, with this sector playing a major role economically. However adaptation has, to a large extent, been limited to the provision of recommendations to forest managers, most of which have only been partially implemented. This paper summarizes research with direct implications for adaptation to climate change within the forestry sector in Sweden. The focus is based in particular on providing examples of adaptations that illustrate the specific Swedish orientation to adaptation, in line with its relatively intensive forest management system. The paper thus illustrates a specific Swedish orientation to adaptation through active management, which can be contrasted with approaches to adaptation in other forestry systems, in particular those with limited management or management based on maintaining natural forests in particular.

  • 38.
    Schweigler, Michael
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Hochreiner, Georg
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    An Engineering Modeling Approach for the Non-Linear Load-Displacement Behavior of Single Dowel Connections: Parameter Study2016Ingår i: Proceedings of the 2016 World Conference on Timber Engineering (WCTE), Vienna University of Technology, Austria , 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    A beam on non-linear elastic foundation model for consistent determination of the non-linear loaddisplacement behavior of single dowel connections is presented. The influence of certain parameters, like the load-tograin direction or the side member thickness on the connection behavior is demonstrated by means of a parameter study and compared to experimental findings.

  • 39.
    Hu, Min
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Olsson, Anders
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Johansson, Marie
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Oscarsson, Jan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Serrano, Erik
    Lund University.
    Assessment of a Three-Dimensional Fiber Orientation Model for Timber2016Ingår i: Wood and Fiber Science, ISSN 0735-6161, Vol. 48, nr 4, 271-290 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wood is an orthotropic material with very different properties along and across fibers, and every board has its own pattern of knots and fiber deviations. Therefore, detailed knowledge of the three-dimensional (3D) fiber orientation of individual boards would enable more accurate assessment of properties such as stiffness, strength, and shape stability. This paper presents a method for modeling 3D fiber orientation of side boards of Norway spruce. The method is based on dot laser scanning and utilization of the tracheid effect, and it is verified by a comparison between strain fields calculated on the basis of the fiber orientation model and corresponding strains determined using digital image correlation (DIC) technique. By means of the method, it is possible to identify knots and to reproduce the fiber orientation in clear wood in the vicinity of knots. Fiber orientation models of side boards including traversing edge knots were established and integrated in finite element models of boards used for simulation of four-point bending tests. The same boards were also tested in laboratory and displacement fields of the wide faces were recorded at different load levels using DIC technique. Comparisons of strain fields from measurements and simulations showed close agreement, regarding both strain patterns and strain levels. Local strain concentrations caused by very small defects were detected using the models and also found from the laboratory test results. The modeling approach may be used both to achieve improved accuracy of existing machine strength grading methods and, after further development, also for more advanced analysis of eg crack propagation and strength of timber.

  • 40.
    Landscheidt, Steffen
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Kans, Mirka
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för maskinteknik (MT).
    Automation Practices in Wood Product Industries: Lessons learned, current Practices and Future Perspectives2016Ingår i: The 7th Swedish Production Symposium SPS, 25-27 October, 2016, Lund, Sweden, Lund, Sweden: Lund University , 2016, , 9 s.E1Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wood product industries are a cornerstone of the Swedish industry and contribute vastly to the total Swedish export value. Wood as material itself has a promising perspective of becoming one of the most valuable resources. Sweden in particular has a long tradition and the knowledge of how to cultivate forests. In comparison to the highly automated forest industries, production systems of Swedish wood products industries are mostly characterized by a low degree of automation, tough manual labour and a relative low competency of the workforce. Facing fiercer competition on a global market, Swedish wood product industries are starting to lose touch with wood working industries in other industrialized European countries. Based upon established literature, this paper systematizes the status of automation practices in wood processing industries. The outcome of this study also outlines the expected effects and the future perspectives of digitalization and robotic automation for wood processing industries in high-1are not ready to implement the necessary standards to enter Industry 4.0. Not only are the technical prerequisites not fulfilled, but also a lack of appropriate production organization, logistics and economic basis is affecting negatively.

  • 41.
    Lindblad, Fredrik
    et al.
    ATEA Logistics.
    Schauerte, Tobias
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för maskinteknik (MT).
    Flinkman, Matti
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Changes in Industry Structure and Concentration?: Welfare Loss due to Perfect Competition in the Swedish Industry for Wooden Single-Family Houses2016Ingår i: 70th Forest Products Society annual convention - new horizons for the forest products industry, June 27-29, 2016, Portland, Madison: Forest Products Society, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    As studies based on data from 2012 show, the Swedish market for wooden single-family houses is highly competitive, with many firms offering relatively homogeneous products or services. In order to serve the demand on that market, only 38 % of the existing firms actually were needed. Thus, an uneven distribution of resource utilization let to welfare losses. Yet since 2012, the demand on the market increased by more than 35 %, which potentially had an effect on resource utilization.

    This study is aiming at describing the development of the structure and concentration in the Swedish industry for wooden single-family houses, for a five year period from 2010 to 2014. This could help to understand, if and how market demand affects structure, concentration rate and consequently welfare loss due to resource utilization. The required data were collected from the annual reports of the 52 relevant firms in the industry. By means of the Herfindahl-Hirschman Index and the Herfindahl-Hershamann Number Equivalent, industry structure and concentration rate was calculated.

    The results will show how the industry structure and concentration rate developed from 2010 to 2015, the distribution of resource for welfare purposes and thus, how many firms there actually were needed to serve the market.

  • 42.
    Lundmark, Tomas
    et al.
    Swedish University of Agricultural Sciences.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Nordin, Annika
    Swedish University of Agricultural Sciences.
    Fahlvik, Nils
    Swedish University of Agricultural Sciences.
    Poudel, Bishnu Chandra
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Comparison of carbon balances between continuous-cover and clear-cut forestry in Sweden2016Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, nr supplement 2, S203-S213 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Continuous-cover forestry (CCF) has been recognized for the production of multiple ecosystem services, and is seen as an alternative to clear-cut forestry (CF). Despite the increasing interest, it is still not well described how CCF would affect the carbon balance and the resulting climate benefit from the forest in relation to CF. This study compares carbon balances of CF and CCF, applied as two alternative land-use strategies for a heterogeneous Norway spruce (Picea abies) stand. We use a set of models to analyze the long-term effects of different forest management and wood use strategies in Sweden on carbon dioxide emissions and carbon stock changes. The results show that biomass growth and yield is more important than the choice of silvicultural system per se. When comparing CF and CCF assuming similar growth, extraction and product use, only minor differences in long-term climate benefit were found between the two principally different silvicultural systems.

  • 43.
    Nilsson, Josefin A.
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Customer requirements on solid wood material: A birch roundwood case-study2016Ingår i: Proceedings of the 12th meeting of the Northern European Network for Wood Science and Engineering (WSE): Wood Science and engineering - a key factor on the transition to Bioeconomy / [ed] Bruno Andersons and Arnis Kokorevics, Latvian State Institute of Wood Chemistry , 2016, 22-28 s.Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Today a majority of the pre-commercial thinning (PCT) cut birch stems in Sweden are retained on the site for biodegradation, since their market value is lower than the cost of harvesting. Some stems are removed as firewood. The uses of the PCT material can be difficult to find, and the costly PCT is carried out in expectation of greater returns later in the forest rotation. There is a growing body of literature that recognises the possibility of using low value wooden material for furniture and interior purposes. While some research has been carried out on character-marked wood, there have been few investigations on utilization of small-dimensioned roundwood. However, proper utilisation of this material requires appropriate matching of the material attributes with the end-user’s expectations on furniture or joinery products. The aim of this work is to understand challenges and possibilities for the utilization of small-dimensioned roundwood birch in furniture and joinery products. The study synthesizes literature on customers’ demands on hardwood and important material properties. A case-study approach was used to evaluate how a bench, made out of small-dimensioned roundwood birch, can meet the requirements from customers and manufacturing industries. The results demonstrate that opportunities exist within the customer segment appealed by naturalistic furniture design. Proposals are made for future research needed for successful use of small-dimensioned roundwood birch for furniture applications.

  • 44.
    Bastani, Alireza
    et al.
    George-August University, Germany.
    Militz, Holger
    George-August University, Germany.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Rohumaa, Anti
    Alto University School of Chemical Technology, Finland.
    Development of bonding strength of modified birch veneers during adhesive curing2016Ingår i: Wood research, ISSN 1336-4561, Vol. 61, nr 2, 205-214 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigated the bonding strength development of furfurylated, N-methylolmelamine (NMM) modified and thermally treated birch veneers glued with hot curing phenolformaldehyde (PF) adhesive in different pressing (20, 160 s) and open assembly times (20 s, 10min). For testing, the automated bonding evaluation system ABES was used with 2 N.mm-2applied pressure at 130°C. The bonding strength of both modified and unmodified samplesincreased significantly by prolongation of the pressing time from 20 to 160 s in all cases andfor both open assembly times. A deviation was observed for the samples treated at 220°C andat 20 s open assembly time. With the exception of NMM modified veneers, bonding strengthdid not change significantly by increasing the assembly time in the case of 20 s pressing forboth modified and unmodified samples. At 160 s pressing time, extension of the assembly timedeveloped a better bonding for controls, NMM modified and thermally treated veneers at 180°C.The combination of 10 min assembly time and 160 s pressing time proved as the optimal bondingcondition for controls, NMM modified and thermally treated veneers at 180°C while the highestbonding strength was noted in 20 assembly time and 160 s pressing time for furfurylated veneers.In most of the cases modification affected negatively the bonding performance of the veneers, inparticular for furfurylated and NMM modified samples.

  • 45.
    Gustafsson, Åsa
    et al.
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för ekonomistyrning och logistik (ELO).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Does quality matter?2016Ingår i: Implementation of wood science in woodworking sector: proceedings / [ed] Ivica Grbac, Zagreb: University of Zagreb, Faculty of Forestry , 2016, 263-270 s.Konferensbidrag (Refereegranskat)
  • 46.
    Hosseinpourpia, Reza
    et al.
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Mai, Carsten
    Georg-August-University Göttingen, Germany.
    Dynamic vapour sorption of wood and holocellulose modified with thermosetting resins2016Ingår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 50, nr 1, 165-178 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Micro-veneers of wood and holocellulose (HC) were modified with the thermosetting resins phenol formaldehyde and melamine formaldehyde. The dynamic water vapour sorption of the modified and untreated veneers was studied in a dynamic vapour sorption apparatus to assess the effects of resin modification. The adsorption of wood and HC as well as the desorption of wood was little affected by the modification in the low relative humidity (RH) range but decreased in the RH range above 60–70 %. The desorption isotherm of HC, however, was increased in the RH range of 15–80 % due to modification. Resin modification gradually decreased the EMC ratio of wood and HC and also influenced the moisture increment, equilibrium time and sorption rate in RH range above 50–60 % RH for wood and above 70–80 % RH for HC. HC exhibited a clearly lower hysteresis than wood. Modification of wood slightly reduced hysteresis compared to untreated wood, but modification of HC clearly increased hysteresis about to the same extent as that of wood. This indicates that the stiffening effect of lignin and thermosetting resins reduces the flexibility of the HC matrix, which results in increased hysteresis.

  • 47.
    Wang, Xiaodong Alice
    et al.
    Luleå University of Technology.
    Björnberg, Jonathan
    Luleå University of Technology.
    Hagman, Olle
    Luleå University of Technology.
    Ahmed, Sheikh Ali
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Wan, Hui
    Mississippi State University, USA.
    Niemz, Peter
    Swiss Federal Institute of Technology in Zurich, Switzerland.
    Effect of Low Temperatures on the Block Shear Strength of Norway Spruce Glulam Joints2016Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 4, 9638-9648 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The block shear strength of Norway spruce (Picea abies (L.) Karst.) glulam joints was tested under low temperature. Glulam samples were glued with the three of the most common outdoor structural adhesives. The cold temperatures tested were 20, −20, −30, −40, -50 and −60 °C. Within the temperature test range, the block shear strength of the glulam joints was resistant to the effect of temperature. As the temperature decreased, the joints’ block shear strength did not show any significant change. In most cases, phenol-resorcinol-formaldehyde (PRF) adhesive yielded the strongest block shear strength, while melamine-formaldehyde (MF) adhesive yielded the weakest block shear strength. Melamine-urea-formaldehyde (MUF) adhesive yielded similar results to those of MF adhesives for all temperatures tested. The block shear strengths of the glulam joints with PRF, MUF and MF adhesives were not sensitive to temperature change. The results indicated that PRF, MUF and MF adhesives are stable for outdoor structural engineered wood construction in cold climate. The results also suggest that the SS-EN 14080 (2013) standard for the block shear method may not be the proper standard for testing differences in shear strength at different temperatures. The EN 302-1 (2011) standard could be more suitable for this purpose.

  • 48.
    Soltani, Abolfazl
    et al.
    Shahid Rajee Teacher Training University, Iran.
    Hosseinpourpia, Reza
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Adamopoulos, Stergios
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Taghiyari, Hamid R.
    Shahid Rajee Teacher Training University, Iran.
    Ghaffari, Ehsan
    Shahid Rajee Teacher Training University, Iran.
    Effects of heat-treatment and nano-wollastonite impregnation on fire properties of solid wood2016Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 4, 8953-8967 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of nano-wollastonite (NW) suspension impregnation on the fire-retarding properties of heat-treated solid wood of three species (beech, poplar, fir) were studied. Heat treatment was performed at two temperatures of 180 °C and 200 °C. Impregnation was carried out at a pressure of 3 bars for 30 min. The fire properties included ignition time, glowing time, back-darkening, back-splitting, back-firing, and length and width of the burnt area. Both impregnation with NW and heat-treatment generally improved all fire-retarding properties, although not always to a significant level. As a mineral material, NW acted like a physical shield against fire penetration into the texture of wood specimens, thus improving fire properties. Moreover, the high thermal conductivity coefficient of wollastonite increased the thermal conductivity of wood, therefore preventing the accumulation of heat at the point nearest to a piloted flame and contributing to the improvement of fire properties. The chemical degradation of wood cell components caused by heat-treatment further improved the fire properties. Cluster analysis indicated the significant effect of species on fire properties. Significant R-square values were found amongst fire properties related to the spread of fire on the surface of specimens. The combination of thermal modification and impregnation with NW provides suitable fire properties for solid wood.

  • 49.
    Lindblad, Fredrik
    et al.
    ATEA Logistics.
    Schauerte, Tobias
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för maskinteknik (MT).
    Flinkman, Matti
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Evaluating profitability of Firms in the Swedish Industry for Wooden Single-Family Houses2016Ingår i: The 70th Forest Products Society annual convention - new horizons for the forest products industry, June 27-29, 2016, Portland, Madison: Forest Products Society, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    The market for Swedish wooden single-family house producers is characterized by perfect competition, i.e. products are highly substitutional and firms mainly compete by prices. Variance in net profit margins, as a key number for profitability, for firms in this industry ranges by 60 %. As net profit margin is defined as net profit divided by revenue, these latter two directly affect net profit margin. Yet, leaving the obvious determining mathematical explanations aside, other factors might affect the profitability of the firms, showing, what distinguishes successful firms from less successful ones.

    This study is aiming at exploring the factors affecting the profitability of Swedish firms producing wooden single-family houses. By means of those factors, variances in net profit margins might be explained more thoroughly. Data from annual reports were collected from 52 firms in the industry and a correlation analysis performed.

    The results will show if there are factors that correlate with net profit margins and if yes, what explanatory power these factors have. This in turn might serve as an input for the firms’ strategic development towards a higher profitability of their businesses.

  • 50.
    Bader, Thomas K.
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY). Vienna University of Technology, Austria.
    Schweigler, Michael
    Vienna University of Technology, Austria.
    Hochreiner, Georg
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Serrano, Erik
    Lund University.
    Dorn, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Enquist, Bertil
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Experimental Assessment of the Load Distribution in Multi-Dowel Timber Connections2016Ingår i: 17th International Conference on Experimental Mechanics, Rhodes, Greece, July 3-7, 2016, 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    An integrative, hierarchically organized testing procedure for the quantification of the load distribution in multi-dowel timber connections is presented herein. The use of contactless deformation measurement systems allowed the combination of test data from single dowel and multi-dowel connections, which gave access to the loads acting on each dowel over the full loading history. As a consequence of the anisotropic material behavior of wood, a nonuniform and progressively changing load distribution among the dowels was found.

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