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  • 151. Dahlblom, Ola
    et al.
    Ormarsson, Sigurdur
    Petersson, Hans
    Prediction of deformations by an extended two-dimensional formulation1996In: Quality wood drying through process modelling and novel technologies / [ed] Alain Cloutier, Yves Fortin, 1996, p. 69-76Conference paper (Refereed)
  • 152.
    Dahlblom, Ola
    et al.
    Lund Institute of Technology, Sweden.
    Persson, Kent
    Lund Institute of Technology, Sweden.
    Ormarsson, Sigurdur
    Petersson, Hans
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Stiffness and shape stability analysis of sawn timber based on experimentally found variations of wood properties1999In: Connection between Silviculture and Wood Quality through Modelling Approaches and Simulation Softwares, 1999Conference paper (Refereed)
  • 153.
    Dahlblom, Ola
    et al.
    Lund Institute of Technology, Sweden.
    Persson, Kent
    Lund Institute of Technology, Sweden.
    Petersson, Hans
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Ormarsson, Sigurdur
    Investigation of variation of engineering properties of spruce1999In: Wood Drying Research & Technology for Sustainable Forestry Beyond 2000, 1999Conference paper (Refereed)
  • 154.
    Dahlblom, Ola
    et al.
    Lund Institute of Technology.
    Petersson, Hans
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Ormarsson, Sigurdur
    Full 3-D FEM-Simulations of Drying Distortion in Spruce Boards based on Experimental Studies2001In: 7th International IUFRO Wood Drying Conference, 2001Conference paper (Refereed)
  • 155.
    Dahlblom, Ola
    et al.
    Lund University, Sweden.
    Petersson, Hans
    Chalmers University of Technology, Sweden.
    Ormarsson, Sigurdur
    Chalmers University of Technology, Sweden.
    Stiffness, strength and shape stability grading analysis of sawn timber based on experimentally found growth characteristics2000In: World Conference on Timber Engineering, 2000Conference paper (Refereed)
    Abstract [en]

    Stiffness, strength and shape stability analysis of sawn timber should be based on how the material properties vary in the stem due to different growth conditions. As part of an EU study, results from investigations of the modulus of elasticity, shrinkage coefficient and spiral grain angle of spruce are presented. The variation in properties with the position in the stem has been investigated. The specimens were sawn from 274 stems in 29 stands in five countries of the European Union. A total of about 7000 small specimens were tested. Results from the modelling of stiffness and moisture-induced deformations of battens are presented. The simulations were based on material data obtained from measurements performed on specimens sawn from the same logs as the battens. The simulation results are compared with experimental results and are of interest for the development of new grading procedures for sawn timber.

  • 156. Dahlblom, Ola
    et al.
    Petersson, Hans
    Persson, Kent
    Ormarsson, Sigurdur
    Experimental investigation of basic properties of spruce1998In: World Conference on Timber Engineering, 1998Conference paper (Refereed)
  • 157.
    Danesh, Mohammad Amin
    et al.
    Islamic Azad University, Iran.
    Ziaei Tabari, Hassan
    Islamic Azad University, Iran.
    Hosseinpourpia, Reza
    Georg-August University, Germany.
    Nazarnezhad, Noradin
    Sari Agricultural Science and Natural Resources University, Iran.
    Shams, Morteza
    Islamic Azad University, Iran.
    Investigation of the morphological and thermal properties of waste newsprint/recycled polypropylene/nanoclay composite2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 1, p. 936-945Article in journal (Refereed)
    Abstract [en]

    The main objective of this research was to study the potential of waste polypropylene and waste newsprint fiber for making wood-plastic nanocomposites. We used 30 wt.% waste newsprint fiber and 10 wt.% compatilizer in this study. Nanoclay was used at two levels: 2.5 and 5% by wt. Materials were mixed with either recycled or virgin polypropylene. The effects of nanoclay (NC) on the mechanical and thermal properties were also studied. The improvements in tensile properties of the blended composites with the addition of NC were further supported by Scanning Electron Microscope (SEM) micrographs and X-Ray Diffraction (XRD) data. Thermal degradation behavior of the composites showed that the degradation temperatures shifted to higher values after addition of nanoclay. The XRD data showed that the relative intercalation of composites with 2.5% nanoclay was higher than 5% nanoclay. The experimental results demonstrated that the waste materials could be used as appropriate alternative raw materials for making low cost wood-plastic composites (WPCs).

  • 158.
    de Borst, Karin
    et al.
    University of Glasgow, UK.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Structure-€“function relationships in hardwood: Insight from micromechanical modelling2014In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 345, p. 78-91Article in journal (Refereed)
    Abstract [en]

    Abstract A micromechanical model is presented that predicts the stiffness of wood tissues in their three principal anatomical directions, across various hardwood species. The wood polymers cellulose, hemicellulose, and lignin, common to all wood tissues, serve as the starting point. In seven homogenisation steps, the stiffnesses of these polymers are linked to the macroscopic stiffness. The good agreement of model predictions and corresponding experimental data for ten different European and tropical species confirms the functionality and accuracy of the model. The model enables investigating the influence of individual microstructural features on the overall stiffness. This is exploited to elucidate the mechanical effects of vessels and ray cells. Vessels are shown to reduce the stiffness of wood at constant overall density. This supports that a trade-off exists between the hydraulic efficiency and the mechanical support in relation to the anatomical design of wood. Ray cells are shown to act as reinforcing elements in the radial direction.

  • 159.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Non-Linear Connection Models in Timber Engineering2016In: Proceedings of the 2016 World Conference on Timber Engineering (WCTE) / [ed] J. Eberhardsteiner, W. Winter, A. Fadai, M. Pöll, Vienna: Vienna University of Technology , 2016Conference paper (Refereed)
    Abstract [en]

    In this contribution, a numerical model for connections in engineered timber structures, using specially designed connection elements, is presented. The model considers the non-linear load-displacement relation typical for many types of connections on different levels and is presented on the example of dowel-type connections. The structural levels investigated herein are a) the embedment behaviour of a dowel into wood; b) the behaviour of a singledowel connection; and c) a multi-dowel connection under a general load case typical for structural applications. A special characteristic considered in the formulation of the connector elements is the unloading behaviour, which is characterized by an initial high unloading stiffness but a very low stiffness when the load is fully removed. The latter is due to remaining permanent deformations in the wood as well as in the metal connector. The modelling approach was found to correlate well with experimental data and gave new insight in the behaviour of dowel connections, particularly as regards the unloading and reloading behaviour with alternating load directions on the single-dowel connection scale.

  • 160.
    Dvinskikh, Sergey V.
    et al.
    Royal Institute of Technology KTH, Division of Physical Chemistry and Industrial NMR Centre, SE-100 44 STOCKHOLM, .
    Furó, István
    Royal Institute of Technology KTH, Division of Physical Chemistry and Industrial NMR Centre, SE-100 44 STOCKHOLM, .
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Söderström, Ove
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Moisture content profiles and uptake kinetics in wood cladding materials evaluated by a portable nuclear magnetic resonance spectrometer2011In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 6, no 3, p. 119-127Article in journal (Refereed)
    Abstract [en]

    We have evaluated the capability of nuclear magnetic resonance (NMR) technology based on small portable magnets for in situ studies of the local moisture content in wood. Low field and low resolution 1H NMR with a unilateral permanent magnet was used to monitor and map the moisture content of wood cladding materials of various types in a spatially resolved manner. The results show that portable NMR equipment based on small open-access permanent magnets can be successfully used for non-invasive monitoring of the moisture content in various extended wood specimens. The moisture content was measured with a depth resolution of 0.2 mm and a maximum penetration depth of 3 mm. This makes the technique suitable for e.g. in situ local moisture content measurements beneath a coating layer in the claddings and it is also possible to relate the moisture level to specific properties of the wood material.

  • 161.
    Eitelberger, Johannes
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    de Borst, Karin
    Vienna University of Technology, Austria.
    Jäger, Andreas
    Vienna University of Technology, Austria.
    Multiscale prediction of viscoelastic properties of softwood under constant climatic conditions2012In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 55, p. 303-312Article in journal (Refereed)
    Abstract [en]

    This paper covers the development and validation of a multiscale homogenization model for linear viscoelastic properties of wood. Starting point is the intrinsic structural hierarchy of wood, which is accounted for by several homogenization steps. Using the correspondence principle, an existing homogenization model for the prediction of elastic properties of wood is adapted herein for upscaling of viscoelastic characteristics. Accordingly, self-consistent, Mori–Tanaka, and unit-cell-based techniques are employed, leading to pointwise defined tensorial creep and relaxation functions in the Laplace-Carson domain. Subsequently, these functions are back-transformed into the time domain by means of the Gaver-Stehfest algorithm. With this procedure the orthotropic macroscopic creep behavior of wood can be derived from the isotropic shear behavior of the lignin-hemicellulose phase. A comparison of model predictions for viscoelastic properties of softwood with corresponding experimentally derived values yields very promising results and confirms the suitability of the model.

  • 162.
    Eliasson, Lars
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ställ krav på virket: Rätt virke för produktion i framtidens trähusfabrik2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates the needs and opportunities for the Swedish wood house industry to obtain wood material with properties meeting demands of both producers and final customers. A common problem within the Swedish wood house industries is the insufficient quality of the wood material that companies purchase for their production. These flaws in quality can render an additional annual cost for the industry of approximately 10 million Euros.

    Wood house companies express a certain resignation regarding communication with wood material suppliers. However, timber suppliers claim that they rather receive very few complaints regarding timber quality from wood house companies and other purchasers. For a timber supplier, being able to offer an acceptable price is often a determining factor, since most deals will go to the supplier offering the lowest price.

    This has led to a non-existent dialogue between suppliers and purchasers regarding how to approach the wood quality issue. This study has, among other things, studied the preparation of sawn wood into finished components, for instance, the production of knotfree boards. The results illustrate the importance of carrying out evaluations of raw material and suppliers. Furthermore, results show that the cutting cost for wood components, including waste is approximately 1/3 of the total cost for ready-made components. However, in relation to the total cost of the house the timber cost is low. This means that a higher price for wood that fully meets the target specifications, will have limited impact on the total cost for the house.

    The wood house industry is recommended to present firm demands for a high-quality material and to evaluate material and suppliers. In addition to this, the wood house industry should aim towards becoming a modern manufacturing industry, like those most successful manufacturing industries in other fields.

  • 163.
    Eliasson, Lars
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Trähusföretag tappar fördel i slarvig tillverkning.2011In: Husbyggaren, ISSN 0018-7968, no 7, p. 24-27Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    BYGGMETODER Ska trä öka sin konkurrenskraft måste trähusföretag och virkesleverantörer bli bättre på att både ställa och uppfylla kravspecifikationer. Idag kan materialspill och felleveranser uppgå till närmare en femtedel av virkeskostnaden.

    Trähusbranschen står inför ett antal utmaningar. Avgörande är att kunna producera attraktiva bostäder till en kostnad som inte är högre än att människor har råd.

    Trähusföretagen utnyttjar inte fullt ut material och metoder som är anpassade för en effektiv produktion av hus i fabrik. I den kontexten får träets miljöfördelar en underordnad betydelse i konkurrensen med andra mindre miljömässigt uthålliga material.

  • 164.
    Elmkvist, Richard
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Transportlogistik: En undersökning av de logistiska flödena hos ett sågverk/- förädlingsföretag i Sverige2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    När företag har en snabb tillväxt genom konsolidering kan det ske att visa aspekter i organisationen blir eftersläpandes. I det här fallet upplever företaget en förlorad kontroll över sina transporter till följd av en allt mer komplex transportlogistik. Målet med den här undersökning var därför att kartlägga företagets transporter.För att effektivt transportera gods krävs det planering, det är viktigt att fordonens hela lastkapacitet utnyttjats, alltså fyllnadsgrad. Det är viktigt att planera efter kortaste sträckan, det är också viktigt att undvika onödig miljöpåverkan. Onödig miljöpåverkan kan ske genom ineffektiv planering som i sin tur resulterar i mindre nödvändiga godstransporter.Kartläggningen i denna undersökningen resulterade i en täckning av de interna transporterna samt transporter till de största avlägg på 85% av vad företaget uppskattar transporterats under ett 2018. Transporter för trärelaterade produkter 2016 uppgick till 4 miljoner tonkilometer, detta var cirka 9,8% av de totala transporterna med lastbil inom Sveriges gränser. En effektiv kedja av logistiska aktiviteter för trävaror garanterar en nedskärning av kostnaderna för transport. Eftersom hänsynen för miljöpåverkan också är stor i Sverige så är en effektiv logistik också nyckeln för att minska sina klimatavtryck.

  • 165. Eriksson, John
    et al.
    Ormarsson, Sigurdur
    Chalmers University of Technology, Sweden.
    Petersson, Hans
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Adaptive Finite Element Analysis of Non-linear Moisture Flow and Associated Distortion Behaviour in Wood2003In: ADMOS Conference on Adaptive Modelling and Simulation, 2003Conference paper (Refereed)
  • 166.
    Eriksson, John
    et al.
    Chalmers University of Technology.
    Ormarsson, Sigurdur
    Chalmers University of Technology.
    Petersson, Hans
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    An experimental and numerical study of the shape stability in glued columns2005In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 63, no 6, p. 423-429Article in journal (Refereed)
    Abstract [en]

    The study concerns the question of how the shape stability features of laminated columns of Norway spruce can be improved in terms of twist through optimal orientation of the individual laminates. Both experimental testing and numerical simulations were employed for evaluating twist stability. In all the columns studied, deformations were measured experimentally at different moisture content levels. A number of columns were also selected for numerical analysis in order to obtain a more thorough understanding of the twist behavior involved, their geometries and material properties of interest being determined. The experimental results showed the twist stability of the columns to be highly dependant upon the internal orientation of the individual laminates. It was also found that high quality columns in terms of shape stability could be manufactured, even when the center-core material has a strong twist tendency. The numerical simulations performed were in close agreement with the experimental results.

  • 167.
    Eriksson, John
    et al.
    Chalmers University of Technology.
    Ormarsson, Sigurdur
    Chalmers University of Technology.
    Petersson, Hans
    Chalmers University of Technology.
    Experimental study of shape stability in glued boards2004In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 62, no 3, p. 225-232Article in journal (Refereed)
    Abstract [en]

    An experimental study of shape stability in wooden glued boards was performed to verify certain results of particular interest obtained earlier in numerical simulations. Possibilities for achieving products of good shape stability by gluing boards together in an optimal way are discussed. Since twist is often the most serious form of distortion defects for the user, it was the main type of board deformation considered. Three types of glued products were tested. The experiments show clearly that glued boards can be produced that remain stable in shape when exposed to extreme variations in moisture. The results agree well with the numerical simulations performed earlier. It was found that initial twist could be reduced by proper application of pressure during gluing and that through gluing the occurrence of cracking defects on visible surfaces could be substantially reduced.

  • 168.
    Eriksson, John
    et al.
    Chalmers University of Technology .
    Ormarsson, Sigurdur
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Chalmers University of Technology .
    Petersson, Hans
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Finite element analysis of coupled nonlinear heat and moisture transfer in wood2006In: Numerical Heat Transfer, Part A Applications, ISSN 1040-7782, E-ISSN 1521-0634, Vol. 50, no 9, p. 851-864Article in journal (Refereed)
    Abstract [en]

    A nonlinear model for analysing heat and moisture flow in wood during drying below the fiber saturation point is presented. The model used considers wood at a macro level without taking the various moisture transports mechanisms at the microscopic level into account. Based on the finite-element method, a coupled system of equations resulting from the adopted heat and moisture transfer equations is established and an iterative scheme is proposed. The numerical procedure is verified by a test example. In a two-dimensional analysis, the influence of the coupling on the combined heat and moisture transfer is studied for a board subjected to a typical kiln-drying condition. How well the results agree with those obtained by introducing a commonly applied simplification is discussed.

  • 169.
    Erlandsson, Lars-Åke
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Rättvist trä: Livscykelanalys av träprodukter ur ett socialt hållbarhetsperspektiv2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the present degree project was to investigate the possibilities of assessing social sustainability and, on this basis, to carry out an equality analysis of wood as a construction material. The latter part of the purpose was met by carrying out social life cycle assessments focusing on gender equality: one for wood as anengineering material and one for house with wooden frame. The result was presented as a gender index which indicated the proportion of the work carried out by women. To gain more knowledge about wood as an engineering material a complete social life cycle assessment is necessary. A complete social life cycle analysis should not be reduced to a single measurement number by merging different effect categories of social sustainability. The conclusion in the report was that such an analysis is better to present in so-called polar diagrams where each individual impact category can be distinguished, but not necessarily all indicators. The method used to assess gender equality can be used to assess other impact categories.

  • 170.
    Esteban, Luis García
    et al.
    Ciudad Universitaria, Spain.
    Simón, Cristina
    Ciudad Universitaria, Spain.
    Fernández, Francisco García
    Ciudad Universitaria, Spain.
    Palacios, Paloma de
    Ciudad Universitaria, Spain.
    Martín-Sampedro, Raquel
    Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Spain.
    Eugenio, María Eugenia
    Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Spain.
    Hosseinpourpia, Reza
    Georg August University, Germany.
    Juvenile and mature wood of Abies pinsapoBoissie: sorption and thermodynamic properties2015In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 49, no 4, p. 725-738Article in journal (Refereed)
    Abstract [en]

    For industrial processes, it is important to study the hygroscopicity and thermodynamic properties of juvenile and mature wood. Samples of Abies pinsapo Boiss. collected in the natural areas of the species in Spain were used to study these properties in both types of wood. The equilibrium moisture contents were obtained, and the 15, 35 and 50 °C isotherms were plotted following the Guggenheim–Anderson–Boer–Dent model. The thermodynamic parameters were calculated using the integration method of the Clausius–Clapeyron equation. Chemical analyses, infrared spectra and X-ray diffractograms were applied to assess chemical modifications and possible changes in the cell wall structure. The chemical composition of the mature wood shows a decrease in the lignin and hemicelluloses content and an increase in the extracts and α-cellulose. The sorption isotherms for the three temperatures studied are higher in the mature wood than in the juvenile wood. Causes of this include the higher content of α-cellulose, the higher crystallinity index and the shorter crystallite length in the mature wood. No difference was found between the juvenile and mature wood in relation to the point of inflexion where the multilayer starts to predominate over the monolayer (approximately 30 %). In terms of the thermodynamic properties, the heat involved is greater in desorption than in adsorption, and more heat is involved in the mature wood than in the juvenile wood.

  • 171.
    Florisson, Sara
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    The effect of initial green state moisture gradients on stresses in timber boards during drying2016In: Eccomas 2016 Proceedings, 2016Conference paper (Refereed)
  • 172.
    Florisson, Sara
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    The effect of surface emission, diffusion and initial moisture profiles on stress development in timber boards2017In: CompWood 2017 : Computational Methods in Wood Mechanics – from Material Properties to Timber: Programme & book of abstract, TU Verlag , 2017Conference paper (Refereed)
  • 173.
    Foti, Dafni
    et al.
    Aristotle Univ Thessaloniki, Greece.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Voulgaridou, Eleni
    Aristotle Univ Thessaloniki, Greece.
    Voulgaridis, Elias
    Aristotle Univ Thessaloniki, Greece.
    Passialis, Costas
    Aristotle Univ Thessaloniki, Greece.
    Amiandamhen, Stephen
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Daniel, Geoffrey
    Swedish University of Agricultural Sciences, Sweden.
    Microstructure and compressive strength of gypsum-bonded composites with papers, paperboards and Tetra Pak recycled materials2019In: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 65, no 1, p. 1-8, article id 42Article in journal (Refereed)
    Abstract [en]

    The incorporation of recycled papers, paperboards and Tetra Pak as filling materials in brittle matrices presents aninteresting approach in the utilization of waste materials for building construction. This paper examines the compressivestrength and microstructure of gypsum-bonded wastepaper-based composites. Recycled wastepaper of varioustypes (office paper, magazine paper and newspaper), cardboards, paper boxes and Tetra Pak were shredded to shortlength strips of about 4 × 18 mm. The shredded materials were used as filling materials in natural gypsum in a ratioof 1:3 (v/v), and water was added to the mix. The paste was formed in cylindrical samples measuring 10 cm in lengthand 5 cm in diameter. Seven different types of composites were produced depending on the material used. Thecomposite products with newspaper and magazine paper had significantly lower density and compressive strength(p < 0.05) than the others. However, the differences were small to have any practical importance. The density valuesranged between 1.26 and 1.34 g/cm3, and compressive strength was the lowest (4.48 N/mm2) in the gypsum–magazinepaper composites and the highest (6.46 N/mm2) in the gypsum–Tetra Pak I composites. Since the samplesproduced in this study exhibited adequate compressive strength, the products could be suitable for such applicationsas interior walls in building constructions. Scanning electron microscopy (SEM) examination of the fractured surfacesrevealed needle-like structures of gypsite crystals surrounding the fibers, which indicates good adhesion between thehydrophobic matrix and lignocellulosic fibers.

  • 174. Fransson, Jonas
    et al.
    Olsson, Axel
    Witten, Thomas
    Blom, Åsa
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Sandberg, Dick (red)
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Svenska barr- och lövträd: - Andvändning och anatomi2007Report (Other academic)
    Abstract [en]

    Swedish softwoods and hardwoods – use and anatomy describe properties

    and macro- and microscopic structures for the most common species in

    Sweden. The softwood species described are pine, spruce and juniper. The

    hardwoods are birch, aspen, alder, beech, oak, ash and maple. The

    physical properties are placed in order of precedence between the different

    species, so that they easily can be compared with each other. Furthermore,

    some examples are given on uses for each species. The work is based on a

    literature survey of Swedish and international literature as well as on own

    studies of wood at a microscopic level. All the species (except aspen, alder

    and maple) are presented with our own pictures taken in a microscope.

    In the first part, the structures of the trees at a macroscopic level are

    described. Macroscopic structures that are described are for example rays,

    annual rings and vessels. This part also describes different cell types and

    the anatomy and chemistry of the cell. In the next part, a collection of

    facts about each species is included. A separation of soft- and hardwood is

    made, and the hardwoods are divided in diffuse-porous, semi-ring-porous

    and ring-porous species.

  • 175.
    Funk, Monika
    et al.
    University of Göttingen, Germany.
    Wimmer, Rupert
    Universität für Bodenkultur Vienna, Austria.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Diotomaceous earth as an inorganic additive to reduce formaldehyde emmissions from particleboards2017In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, no 2, p. 92-97Article in journal (Refereed)
    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.

  • 176.
    Füssl, Josef
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Computational Mechanics for Advanced Timber Engineering: from material modeling to structural applications2012In: IACM Expressions, no 32, p. 6-11Article in journal (Other academic)
  • 177.
    Gamstedt, E. Kristofer
    et al.
    Uppsala University.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    de Borst, Karin
    University of Glasgow, UK.
    Mixed numerical–experimental methods in wood micromechanics2012In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 47, no 1, p. 183-202Article in journal (Refereed)
    Abstract [en]

    Mixed numerical–experimental methods are increasingly used in various disciplines in materials science, recently also in wood micromechanics. Having a relatively irregular microstructure, direct interpretation of mechanical tests is not always possible since structurally specific properties are quantified rather than general material properties. The advent of combined numerical–experimental methods unlocks possibilities for a more accurate experimental characterization. A number of examples of mixed methods pertaining to both emerging experimental techniques and physical phenomena are presented: nano-indentation, moisture transport, digital-image correlation, dimensional instability and fracture of wood-based materials. Successful examples from other classes of materials are also presented, in an attempt to provide some ideas potentially useful in wood mechanics. Some general pit-falls in parameter estimation from experimental results are also outlined.

  • 178.
    Gamstedt, Kristofer
    et al.
    Uppsala University.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    de Borst, Karin
    University of Glasgow, UK.
    Mixed Numerical-Experimental Methods in Wood Micromechanics2012In: COST Action FP 0802: Experimental and computional micro-characterization techniques in wood mechanics, Edinburgh, UK, 2012, p. 86-87Conference paper (Other academic)
  • 179.
    Gascón-Garrido, P
    et al.
    Georg-August-University Göttingen, Germany.
    Oliver-Villanueva, JV
    Polytechnic University of Valencia, Spain.
    Ibiza-Palacios, MS
    Furniture and Packaging Research Institute, Spain.
    Militz, H
    Georg-August-University Göttingen, Germany.
    Mai, C
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Georg-August-University Göttingen, Germany ; Technological Educational Institute of Larissa, Greece.
    Resistance of wood modified with different technologies against Mediterranean termites (Reticulitermes spp.)2013In: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 82, p. 13-16Article in journal (Refereed)
    Abstract [en]

    A laboratory no-choice test following the standard EN-117 was conducted to evaluate the efficacy of wood modified with different technologies against subterranean termites of the genus Reticulitermes spp. European beech modified with DMDHEU, acetylated radiata pine, and furfurylated Southern yellow pine were used for termite testing. Before the bioassay, half the number of the specimens (including controls) was subjected to an accelerated aging test according to EN-84. The specimens were exposed for 8 wk to the termites. Additionally, mass losses were measured. The results indicated that the feeding pressure was sufficient according to EN-117 for a valid test. Acetylated wood and DMDHEU-modified wood were classified as durable, showing excellent termite resistance. Furfurylated wood was resistant in the case of non-leached specimens; however, the leaching process led to a classification of non-durable. Thus, the new modification technologies open a real possibility of their use in the Mediterranean region as alternative preventive treatments against subterranean termites.

  • 180.
    Gellerich, Antje
    et al.
    Georg-August-University Göttingen, Germany.
    Röhl, Kay
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Georg-August-University Göttingen, Germany.
    Militz, Holger
    Georg-August-University Göttingen, Germany.
    Evaluation of fungal infestation and decay in a simulated use class 3 situation (block test) after some years of exposure2012In: The 43rd Annual Meeting of IRG: Abstracts of documents, Stockholm, 2012Conference paper (Refereed)
    Abstract [en]

    The so named “block test” was designed as part of the assessment methodology for testing the behaviour of natural and modified wood used under use class 3 (EN 335-2) conditions. The test was developed to expose the wood close to the ground to an environment with high humidity and high biological activity, but not in soil contact. The present study describes the evaluation of fungal infestation and decay of untreated samples in different blocks depending on their exposure time, positioning within the block and wood species. After 4 years outside exposure samples showed visible signs of decay. The highest rate of decay was visible in the middle layers of the block. After 7 and 8 years outside exposure, samples of all layers were infested with a similar intensity of different types of decay. The results have shown that in the bottom layer close to ground the major type of decay is white rot as well as white rot in combination with soft rot. In contrast, samples from the middle layers and top layer were infested mainly by brown and white rot but also soft rot was observed. The test setup is according the definition of use classes a method for use class 3 applications because the samples are out of ground contact. But the infestation of samples in all layers by soft rot indicated that under use class 3 test conditions but with elevated moisture conditions soft rot attack can occur and should make part of a proper test design.

  • 181.
    Gečys, Tomas
    et al.
    Vilnius Gediminas Technical University, Lithuania.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Kajėnasa, Simonas
    Vilnius Gediminas Technical University, Lithuania.
    Influence of the rope effect on the slip curve of laterally loaded, nailed and screwed timber-to-timber connections2019In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 228, p. 1-13, article id 116702Article in journal (Refereed)
    Abstract [en]

    Timber-to-timber connections with different types of screws and nails were experimentally investigated with the aim to quantify the contribution of their axial resistance to their slip and their lateral load bearing capacity, which is the so-called rope effect in dowel-type timber connections. Five different types of screws, including partly threaded and double-threaded screws, as well as three types of nails, including smooth round nails, twisted square-sectioned and grooved nails, were used in the experimental investigations in order to cover a broad range of axial resistance of fasteners. Their behavior was tested in single shear and double shear timber-to-timber connections. In addition to connection testing, system and material properties were experimentally determined. This gave input to design equations and allowed for a comparison of the mechanical model in the European design standard for timber structures, Eurocode 5, with experiments. Experiments indicate that the initial slip modulus in the quasi-elastic domain is not influenced by withdrawal capacity of the fastener, while it shows pronounced influence on load-carrying capacity and the nonlinear shape of the slip curve of the connection at larger deformations. Rope effect strongly depends on fastener properties. High axial resistance of fasteners leads to highly non-linear slip curves and design equations tended to underestimate strength including the rope effect up to a displacement limit of 15 mm. Experimentally observed failure modes were well in line with the theoretical failure modes predicted by the design model. The provided experimental results are motivation for improvement of design models and development of analytical and numerical models that account for nonlinear effects in the complex load transfer mechanism.

  • 182.
    Gečys, Tomas
    et al.
    Vilnius Gediminas Technical University, Lithuania.
    Daniunas, Alfonsas
    Vilnius Gediminas Technical University, Lithuania.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Wagner, Leopold
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    3D finite element analysis and experimental investigations of a new type of timber beam-to-beam connection2015In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 86, p. 134-145Article in journal (Refereed)
    Abstract [en]

    Abstract A new type of semi-rigid timber beam-to-beam connection and its behavior under bending is presented. This connection consists of four identical steel parts, which are inserted into the timber beams in the tension and compression zone of the connection. These steel parts are easily connected by mounting bolts on the construction site. In order to avoid initial slip, gaps between the timber and the steel parts are filled using two different types of filler materials, namely cement based (CEM) or polyurethane based (PUR) filler. In this study, the connection is modeled by means of the Finite Element (FE) Method and the modeling results are compared to the results of an experimental assessment of the proposed connection under bending. The material model for timber encompasses a Hill criterion in combination with cohesive surface contact in order to depict both, yielding in compression and brittle failure in shear and tension perpendicular to the grain. The experimentally observed decisive failure mode, i.e. shear block failure, could be reproduced by the model. Subsequently, the FE model was used to investigate the effect of using different filler materials, or not considering the filler in the analysis at all. In addition, a particular influence of clamping bolts in the timber on the strength of the connection was revealed. The FE analysis excluding these bolts showed good agreement with the experiments in terms of the strength of the connection, while considering these bolts led to an overestimation of the strength. This is a consequence of the considerable influence of the clamping bolts on stresses perpendicular to the grain in the timber in the block-shear area, and therefore, on shear failure initiation. Using the CEM filler hardly changed the overall behavior of the connection as compared to the analyses without filler material, while the PUR filler leads to a less ductile overall behavior. This is well in line with experimental observations. The application of modeling approaches for timber has proven suitable for the analysis of such a type of timber beam-to-beam connection and, consequently, might be used for further optimization of this connection.

  • 183.
    Girhammar, Ulf Arne
    et al.
    Umeå universitet, Institutionen för tillämpad fysik och elektronik.
    Källsner, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Daerga, Per Anders
    Umeå universitet, Institutionen för tillämpad fysik och elektronik.
    Recommendations for design of anchoring devices for bottom rails in partially anchored timber frame shear walls2010In: Proceedings of the 11th World Conference on Timber Engineering / [ed] Ario Ceccotti, 2010Conference paper (Refereed)
  • 184.
    Gloimüller, Stefan
    et al.
    Vienna University of Technology, Austria.
    de Borst, Karin
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Determination of the linear elastic stiffness and hygroexpansion of softwood by a multilayered unit cell using poromechanics2012In: Interaction and Multiscale Mechanics, An International Journal, ISSN 1976-0426, Vol. 5, no 3, p. 229-265Article in journal (Refereed)
    Abstract [en]

    Hygroexpansion of wood is a known and undesired characteristic in civil engineering. When wood is exposed to changing environmental humidity, it adsorbs or desorbs moisture and warps. The resulting distortions or - at restrained conditions - cracks are a major concern in timber engineering. We herein present a multiscale model for prediction of the macroscopic hygroexpansion behavior of individual pieces of softwood from their microstructure, demonstrated for spruce. By applying poromicromechanics, we establish a link between the swelling pressure, driving the hygroexpansion of wood at the nanoscale, and the resulting macroscopic dimensional changes. The model comprises six homogenization steps, which are performed by means of continuum micromechanics, the unit cell method and laminate theory, all formulated in a poromechanical framework. Model predictions for elastic properties of wood as functions of the moisture content closely approach corresponding experimental data. As for the hygroexpansion behavior, the swelling pressure has to be back-calculated from macroscopic hygroexpansion data. The good reproduction of the anisotropy of wood hygroexpansion, based on only a single scalar calibration parameter, underlines the suitability of the model. The multiscale model constitutes a valuable tool for studying the effect of microstructural features on the macroscopic behavior and for assessing the hygroexpansion behavior at smaller length scales, which are inaccessible to experiments. The model predictions deliver input parameters for the analysis of timber at the structural scale, therewith enabling to optimize the use of timber and to prevent moisture-induced damage or failure.

  • 185. Godinho, Pedro Miguel Jesus de Sousa
    et al.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Eberhardsteiner, Josef
    Hellmich, Christian
    Multiscale modelling of transversely isotropic and anisotropic planar fiber networks: current results for elasticity and strength of paper, and potential applications to related materials2018In: Engineering Mechanics Institute Conference 2018 (EMI 2018), Cambridge, Massachusetts, USA, 2018Conference paper (Refereed)
  • 186.
    Godinho, Pedro M.J.S.
    et al.
    Vienna University of Technology, Austria.
    Jajcinovic, Marina
    Graz University of Technology, Austria.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    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 applications2017In: 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 , 2017Conference paper (Refereed)
  • 187. Godinho, Pedro M.S.J.
    et al.
    Jajcinovic, Marina
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fischer, Wolfgang J.
    Hirn, Ulrich
    Bauer, Wolfgang
    Hellmich, Christian
    A continuum micromechanics approach to the strength of planar fiber networks: paper material applications2017In: Vienna Young Scientists Symposium, June 1-2, 2017, Vienna, Austria, 2017Conference paper (Refereed)
  • 188.
    Grubîi, Victor
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Occurence of shake in oak (Quercus spp.) and its effect on flooring top-layer quality2018In: 8th Hardwood Conference. Sopron, Hungary. 25-26 October 2018: With special focus on "New Aspects of Hardwood Utilization - from Science to Technology" / [ed] Robert Németh, Alfred Teischinger, Peter Rademacher, Miklos Bak, Sopron, Hungary: University of Sopron Press , 2018, p. 59-60Conference paper (Refereed)
    Abstract [en]

    Oak (Quercus spp.) is generally preferred wood species as surface material in flooring products realization. The presence of defects such as cracks limits the utilization of the raw material and ultimately, limits the competitiveness of wood in the flooring market when compared to other materials.

    The objective of this study was to develop the theoretical aspects for crack-type identification based on the appearance of the sawn top-layer lamellas and evaluate the influence of crack occurrence on the quality of flooring top-lamellas.

    The results of this study provide an insight for crack-type identification on the surface of oak (Quercus spp.) flooring top-lamellas and wood quality optimisation aspects.

  • 189.
    Grubîi, Victor
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Occurrence of shake in oak (Quercus ssp.) and it's effect on flooring top-layer quality2018In: 8TH HARDWOOD CONFERENCE WITH SPECIAL FOCUS ON NEW ASPECTS ON HARDWOOD UTILIZATION - FROM SCIENCE TO TECHNOLOGY / [ed] Nemeth, R Teischinger, A Rademacher, P Bak, M, University of Sopron, Hungary , 2018, p. 59-60Conference paper (Refereed)
    Abstract [en]

    Oak (Quercus ssp.) is generally preferred wood species as surface material in flooring products realization. The presence of defects such as cracks limits the utilization of the raw material and ultimately, limits the competitiveness of wood in the flooring market when compared to other materials. The objective of this study was to develop the theoretical aspects for crack-type identification based on the appearance of the sawn top-layer lamellas and evaluate the influence of crack occurrence on the quality of flooring top-lamellas. The results of this study provide an insight for crack-type identification on the surface of oak (Quercus ssp.) flooring top-lamellas and wood quality optimisation aspects.

  • 190.
    Gustafsson, Per Johan
    et al.
    Lund University.
    Emilsson, Arne
    Lund University.
    Crocetti, Roberto
    Lund University.
    Ormarsson, Sigurdur
    Lund University.
    Provningar av limträs skjuvhållfasthet hösten 20092010Report (Other academic)
  • 191.
    Gustafsson, Åsa
    et al.
    Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Does quality matter?2016In: Implementation of wood science in woodworking sector: proceedings / [ed] Ivica Grbac, Zagreb: University of Zagreb, Faculty of Forestry , 2016, p. 263-270Conference paper (Refereed)
  • 192.
    Gustafsson, Åsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Rask, Lars-Olof
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Proposing a Research Agenda for Swedish Sawmill Distribution Channel Challenges2010In: Presented at SSFE 2010 / [ed] Bo Jellesmark Thorsen, 2010Conference paper (Refereed)
    Abstract [en]

    Purpose; The purpose of this study is to identify distribution channel research needs given the variety of distribution channel challenges among Swedish sawmill companies.

    Design / methodology / approach; Explorative case study research

    Findings: The paper proposes a typology of sawmill distribution channel challenges, as well as aligns research needs with distribution channel type. The typology is based on i) number of sawmill units within the firm, in combination with ii) distribution channel heterogeneity. Significant management decisions and research needs are identified for the different types.

    Research limitations / implications; This research makes tentative statements regarding typology of sawmill distribution channel challenges and potential research needs in the Swedish sawmill industry with regards to the respective typology. However, further research is needed in order to validate these results.

    What is original/value of paper: This paper focus on the sawmill industry distribution channels, which is a neglected but important area for sawmill’s competitive advantage. The paper also contributes to research by applying contingency theory and typology as an approach to deal with the variety of sawmills distribution channel challenges.

    Keywords; Typology, distribution channel challenges, research needs, and Swedish sawmill industry

  • 193.
    Habite, Tadios
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Automatic detection of pith location along boards of Norway spruce on the basis of data from optical scanning of longitudinal surfaces2019In: CompWood 2019 - International Conference on Computational Methods in Wood Mechanics - from material properties to Timber Structures, Växjö, Sweden, June 17-19, 2019, Växjö: Lnu Press , 2019, p. 64-64Conference paper (Refereed)
    Abstract [en]

    Different mechanical and physical properties of wood are related to the location of pith. Norway spruce wood from the centre of logs, close to the pith, is characterized by lower longitudinal MOE, larger spiral grain angle, and larger longitudinal shrinkage coefficient than what wood farther away from the pith is [1]. Thus, knowledge of pith location along timber boards may play an important role in both appearance grading and in assessment of mechanical properties such as strength [2]. The current work aims to develop an algorithm which is capable of automatically estimating the pith location of Norway spruce boards, along the boards’ length direction, by utilizing optical scanning of longitudinal surfaces. The initial step of the algorithm is to identify defect free sections along the timber board. This is done by utilizing data from tracheid effect scanning of the four sides of the timber board. Thereafter, a continuous wavelet transform (CWT), similar to fast Fourier transform, is applied on grey scale images from scanning, to analyse the variation of light intensity across the four surfaces at selected positions along the board. Obtained local frequencies correspond to the local annular ring pattern on surfaces. Then, assuming that annular growth rings are concentric circles with the pith in the centre, detected local annular ring wavelengths (using CWT) and artificial annual ring wavelengths corresponding to different hypothetical locations of pith are compared, and an optimization procedure is used to identify the location of pith that minimizes the discrepancy between the detected and artificial sets of annular ring wavelengths. Figure 1 shows grey scale images of short segments of longitudinal surfaces, graphs of the detected local annual ring widths, and a photograph of the board cross section where the determined location of pith is marked out. Preliminary results reveal that data from optical scanners and the suggested method allow for accurate detection of annular ring width and location of pith along boards.

  • 194.
    Habite, Tadios
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Detection of Pith Location of Norway Spruce Timber Boards on the Basis of Optical Scanning2019In: Proceedings, 21st international nondestructive testing and evaluation of wood symposium: Freiburg, Germany / [ed] Xiping Wang; Udo H. Sauter; Robert J. Ross, Madison, U.S.A: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory , 2019, p. 268-275Conference paper (Refereed)
    Abstract [en]

    Optical scanners are used in the woodworking industry to detect various defects, such as dead and live knots, cracks, and fibre distortions, which are important for the visual appearance grading of wood. Data from scanning is also used to assess mechanical properties such as bending and tensile strength, for the purpose of machine strength grading of sawn timbers. Knowledge of annular ring width and location of pith in relation to board cross-sections, and how these properties vary in the longitudinal direction of boards, is relevant for many purposes, such as assessment of shape stability and mechanical properties of timber. Therefore, the purpose of the present research is to evaluate possibilities to determine annular ring width and location of pith on the basis of scanning of surfaces parallel to the longitudinal board direction. The first step of this novel method is to identify clear wood sections, free of defects along boards. Then time-frequency analysis is applied to assess the variation of light intensity over surfaces of these sections, such that local wavelengths, related to the annular ring width patterns are detected on all four surfaces around the board. Finally, the location of pith is calculated by comparing annular ring width distributions on the different surfaces, and assuming that annular rings are concentric circles with the pith in the centre. Results indicate that optical scanners and the suggested method allow for accurate detection of annular ring width and location of pith along boards.

  • 195.
    Hafmar, Jonas
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Eliasson, Robert
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Fukthaltsförändringar för skogsbränsle: En jämförelse av torkförloppet i grönrisskotade och brunrisskotade vältor2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 196.
    Hallingbäck, Henrik R.
    et al.
    Swedish University of Agricultural Sciences.
    Högberg, Karl-Anders
    The Forestry Research Institute of Sweden.
    Säll, Harald
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Lindeberg, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Marie
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Jansson, Gunnar
    The Forestry Research Institute of Sweden.
    Optimal timing of early genetic selection for sawn timber traits in Picea abies2018In: European Journal of Forest Research, ISSN 1612-4669, E-ISSN 1612-4677, Vol. 137, no 4, p. 553-564Article in journal (Refereed)
    Abstract [en]

    In breeding Norway spruce, selection for improved growth and survival is performed at age 10-15 years in order to optimize genetic gain per year. We investigated whether a selection based on wood traits such as density and grain angle, measured under bark in the field at the same age would be informative enough with respect to structural quality traits of sawn boards. To achieve this objective, a sawing study was conducted on the butt logs of 401 trees from a 34-year-old Norway spruce progeny trial situated in southern Sweden. Stem discs were excised from the top of the logs and radial profile data of grain angle, and wood density was recorded for specific annual rings. The sawn and dried boards were assessed for structural traits such as twist, board density, bending stiffness (static modulus of elasticity, sMoE) and bending strength (modulus of rupture, MoR). Additive genetic correlations (r (a)) between single annual ring density measurements and board density, sMoE and MoR were consistently strong (r (a)> 0.7) for annual rings 5-13. Genetic correlations of similar magnitude between grain angle and board twist were estimated for all investigated annual rings (from 2 to around 26 under bark). Consequently, it was found that indirect selection for wood density and grain angle at the tree age 10-16 years would result in more genetic gain per year than selection at later ages. This makes it feasible to perform simultaneous selection of progeny in the field for both growth and wood traits at similar ages.

  • 197.
    Hameed, Mahmood
    Damascus University, Syria.
    On the Determination of some physical Properties of Charcoal from some wood Species (Quercus calliprinous, Quercus infectoria, Arbutus andrachne, Eucalyptus camaldulensis )2009In: Damascus University Journal for the agricultural Science, Vol. 2, p. 233-246Article in journal (Refereed)
    Abstract [en]

    This investigation has Determinated some physical Properties of Charcoal from some wood Species (Quercus calliprinous, Quercus infectoria, Arbutus andrachne, Eucalyptus camaldulensis). The Charcoal of Quercus calliprinous has heavy weight, full of rents in its cross section toward the rays; the annual growth rings are not clear on it. It has coarse or rough surface because the bark was pasted on the wood after the stem had charted or carbonized. It needs five minuets to start lighting and keeps glowing for ten minuets, no smoke or smell and it remains firm after glowing. While the Charcoal of Arbutus andrachne is lighter than the Charcoal of Quercus calliprinous , its cross section is smooth and has a clear luster moreover  shows clearly annual growth rings. It gives sparks during its lighting and needs six minuets to have a total glowing and destroyed after lighting or combustion. The Charcoal of Quercus infectoria   has a medium weight to compare with the Charcoal of Quercus calliprinous, its cross section has a little luster and relative clearly annual growth rings and rays, and it needs eight minuets to begin lighting. The Charcoal of Eucalyptus camaldulensis has light weight too and lighting slowly, its cross section has a luster and unclearly annual growth rings and rays. It gives smoke and smell during its lighting. The results of physical properties have established that the Charcoal of Quercus calliprinous has the highest value for heat of combustion, but the value of heat of combustion for Charcoal of Quercus infectoria is higher than that for the Charcoal of Arbutus andrachne. The Charcoal of Eucalyptus camaldulensis has the lowest value for the heat of combustion. Therefore the Charcoal of Quercus calliprinous is considered the best type of charcoal and superior. The Charcoal of Eucalyptus camaldulensis has the highest value for the specific heat capacity. While the Charcoal of Quercus calliprinous shows the lowest value for the specific heat capacity. The specific heat capacity for Charcoal of Quercus infectoria is lower than that for the Charcoal of Arbutus andrachne.                                                                                               

     

     

  • 198.
    Hameed, Mahmood
    Damascus University, Syria.
    The Influence of Parafin emulsion on the physical- and mechanical Properties of Medium Density Fiber board (MDF) from Cotton Stems (Gossypium sp.) bonded with Urea formaldehyde    resin (UF).2010In: Damascus University Journal for the agricultural Science., Vol. 26, no 2, p. 179-192Article in journal (Refereed)
    Abstract [en]

    This investigation has established the Possibility of improving the values of physical-(Water absorption and cross-swelling after 2, 24, and 48 hours) and mechanical Properties (binding strength and cross-tensile strength) of Medium Density Fiber board (MDF) from Cotton Stems (Gossypium sp.) bonded with Urea formaldehyde    resin (UF) by adding Parafin emulsion (0.5 % or 1 % to the dry weight of the fibers) when producing the Medium Density Fiber board (MDF) to reach the mean of values for the physical-(Water absorption and cross-swelling after 2, 24, and 48 hours) and mechanical Properties (binding strength and cross-tensile strength) of Medium Density Fiber board (MDF) in the European Standard.                                                           

  • 199. Hameed, Mahmood
    The Possibility of Producing Environment Products from Wastes by-Product of Olives2005In: Damascus University Journal for the agricultural Science, Vol. 2, no 113, article id 124Article in journal (Refereed)
    Abstract [en]

     This investigation has established the possibility of producing the following

    Environment friendly products from the wastes by-product of olives:

     1-Particleboard from Byrene (Waste after the oil has been extracted from the second time with Naphtha). This product has good physical-, mechanical- and chemical

    Properties and very economical.

     2-Barbecue charcoal from Dakka ( Dakka is produced by Partial burning of Byrene), which is superior to oak charcoal which is considered the best type of charcoal for barbecuing, in the following:

     -Instant lighting – no need for lighter fluid.

    -Long-lasting.

    -No smoke or smell.

    -Reusable after quenching with water.

    -High specific heat capacity and heat of Combustion.

    -Very economical.

    3-Organic fertilizer (Compost) from Byrene which can be used to improve the physical Properties of soils.

     

  • 200. Hameed, Mahmood
    The Possibility of Producing Medium Density Fiber board (MDF) from Cotton  Stems (Gossypium sp.) and Determination of its physical- and mechanical Properties2008In: Damascus University Journal for the agricultural Science, Vol. 2, p. 86-101Article in journal (Refereed)
    Abstract [en]

    This investigation has established the Possibility of Producing Medium Density Fiber board (MDF) from Cotton Stems (Gossypium sp.) left after cotton picking. This product has good physical-( moisture content, density, absorption and cross-swelling after 2, 24, and 48 hours) and mechanical Properties (binding strength and cross-tensile strength) and is very economical. Although the mean of values for cross swelling and absorption were higher than the mean of values for cross swelling and absorption of standard Medium Density Fiber board (MDF) which have been determined according to European Norms EN (DIN, 1999). These values were satisfactory, because we didn't use the water proofing material (Parafin emulsion) when producing the Medium Density Fiber board (MDF) which is normally used in Europe (between 0.25-1 % according to the dry weight of the fibers) Haygreen et. al., (2003).

     

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