Sökning: "wood properties."

Visar resultat 1 - 5 av 488 avhandlingar innehållade orden wood properties..

  1. 1. Multiphase continuum modeling of wood : A hybrid mixture theory approach

    Författare :Winston Mmari; Björn Johannesson; Lynn Schreyer; Linnéuniversitetet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Moisture transport; Coupled heat and moisture; Over-hygroscopic; Hybrid mixture theory; Mixture theory; Swelling; Hygro-mechanical; Non-linear elasticity; Large deformation; Phase field crack model; Anisotropic cracking; FEM; Numerical model; Norway spruce; Wood; Porous media; Forestry and Wood Technology; Skog och träteknik;

    Sammanfattning : Wood has been used as a construction material for a very long time. The development of efficient industrial production processes of wood has expanded the use of the material with the introduction of new products, such as engineered wood products. LÄS MER

  3. 2. Local variability in chemical and physical properties of spruce wood fibers

    Författare :Anna Bergander; KTH; []
    Nyckelord :cell walls; chemical composition; elastic constants; elastic strength; Fiber properties; Fibril angles; Mathematical models; Microscopy techniques; Picea Abies; Stiffness; Tensile properties; Wood polymers; Wood;

    Sammanfattning : Wood is well known to be a heterogeneous native materialwith large variations in its composite properties, includingvariations whose origins have not yet been completelyidentified. Traditionally, the macroscopic variations in woodhave received the most attention; for example, the variation indensity from the pith to the bark in trees. LÄS MER

  4. 3. Wood Hemicelluloses - Fundamental Insights on Biological and Technical Properties

    Författare :Jennie Berglund; Mikael Lindström; Gunnar Henriksson; Francisco Vilaplana; Jakob Wohlert; Martin Lawoko; Maija Tenkanen; KTH; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; hemicellulose; wood; glucomannan; xylan; structure; acetylation; flexibility; solubility; interaction with cellulose; stability.; hemicellulosa; trä; glukomannan; xylan; struktur; acetylering; flexibilitet; löslighet; interaktion med cellulosa; stabilitet.; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : Hemicelluloses are a group of heterogeneous polysaccharides representing around 30 % of wood where the dominating types are xylans, glucomannans and xyloglucans. Hemicelluloses complex molecular structure makes it difficult to understand the relationship between structure and properties entirely, and their biological role is not yet fully verified. LÄS MER

  5. 4. Moisture-induced stress and distortion of wood : A numerical and experimental study of wood's drying and long-term behaviour

    Författare :Sara Florisson; Sigurdur Ormarsson; Johan Vessby; Kent Persson; Linnéuniversitetet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; analytical method; calibration; controlled climate; creep; distortion; experimental methodology; FEM; fibre orientation; mechano-sorption; moisture transport; natural climate; Norway spruce; numerical model; three-dimensional; timber beam; validation; wood; Byggteknik; Civil engineering; Forestry and Wood Technology; Skog och träteknik;

    Sammanfattning : With the current advances made in three-dimensional modelling of wood, it is possible to provide an overall picture of moisture flow, and moisture-induced stress and deformations, whereas previously, experiments only provided local measurements. The main aim of the doctoral thesis is to investigate the possibilities of the developed three-dimensional numerical model to predict the behaviour of wood when simultaneously exposed to a mechanical load and a particular climate. LÄS MER

  7. 5. Acetylation of Solid Wood. Wood Properties and Process Development

    Författare :Pia Larsson Brelid; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microwave heating; deformation; wood; hardness; adhesive bonding; power penetration depth; shear strength; delamination; acetylation; pH; bending strength; dielectric properties; stability;

    Sammanfattning : The influence of acetylation on selected wood properties has been determined for Scandinavian pine and spruce wood, in order to predict the behavior of acetylated wood when it is used in different applications. Only minor differences in both bending strength and the modulus of elasticity were obtained for acetylated wood when compared with unmodified wood, and can, for practical applications, be considered unaltered. LÄS MER