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1. 6. Strength grading of structural timber and EWP laminations of Norway spruce : Development potentials and industrial applications

   Författare :Jan Oscarsson; Anders Olsson; Marie Johansson; Hans Joachim Blass; SE-351 96 Växjö Videum Science Park SP Technical Research Institute of Sweden SP Wood Technology; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fibre angle; grain angle; knots; laser scanning; machine strength grading; modulus of elasticity; side boards; strain; structural timber; wet gluing; wood; Byggteknik; Civil engineering;

   Sammanfattning : Machine strength grading of structural timber is a sawmill process by which considerable value is added to sawn products. The principle of such grading is that the strength of a timber member is predicted on the basis of a so called indicating property (IP) which, in general, represents an averaged value of the modulus of elasticity (MOE) measured over a board length of about one meter or more. LÄS MER

3. 7. On the Adhesion Between Substrates Covered with Polyelectrolyte Multilayers

   Författare :Rikard Lingström; Lars Wågberg; Lennart Piculell; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fibre; polyelectorlyte; multilayer; wettability; contact angle; paper strength; atomic force microscopy; surface force apparatus; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : This thesis examines the formation of Polyelectrolyte Multilayers (PEM) on cellulose fibres as a new way of influencing the fibre surface and the adhesion between wood fibres. The aim of the study was to enhance the fundamental understanding of the adsorption mechanisms behind the formation of Polyelectrolyte Multilayers on cellulose fibres; to study how the properties of the layers can be influenced and to show how the properties of the layers influence the adhesion between the fibres and the strength of paper sheets made from the PEM treated fibres. LÄS MER

4. 8. Strength grading of structural timber and EWP laminations of Norway spruce : Development potentials

   Författare :Jan Oscarsson; Anders Olsson; Marie Johansson; Mikael Perstorper; SP Sveriges Tekniska Forskningsinstitut; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; bending strength; fibre angle; grain angle; knots; laser scanning; machine strength grading; modulus of elasticity; strain measurement; structural timber; tensile strength; wood; böjhållfasthet; draghållfasthet; elasticitetsmodul; fibervinkel; konstruktionsvirke; kvistar; laserskanning; maskinell hållfasthetssortering; trä; töjningsmätning; Byggteknik; Civil engineering;

   Sammanfattning : Strength grading of structural timber is a process by which value is added to sawn products. It is to the greater part carried out using machine grading based on statistical relationships between so called indicating properties and bending strength. LÄS MER

5. 9. Hygroelastic behaviour of wood-fibre based materials on the composite, fibre and ultrastructural level

   Författare :Razvan Cristian Neagu; Kristofer Gamstedt; Staffan Toll; KTH; []
   Nyckelord :wood fibres; ultrastructure; structure-property relations; microfibril angle; composites; characterization methods; hygroelastic properties; micromechanics; modelling; reinforcement potential; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Wood fibres can be used as reinforcement in plastics for load carrying purposes. Some advantages compared with conventional man-made fibres are that wood fibres come from a renewable resource, have high specific stiffness and strength, are generally less hazardous to health, biodegradable, and can be manufactured at low cost and high volumes. LÄS MER

7. 10. Local variation in bending stiffness in structural timber of Norway spruce : for the purpose of strength grading

   Författare :Min Hu; Marie Johansson; Linnéuniversitetet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; digital image correlation; fibre angle; high resolution; laser scanning; local stiffness; MOE profile; mode shape curvature; strain field; strength grading; structural timber; tracheid effect; Digital image correlation; fibervinkel; laserskanning; lokal styvhet; MOE-profil; töjningsfält; hållfasthetssortering; konstruktionsvirke; trakeideffekt; Forestry and Wood Technology; Skog och träteknik;

   Sammanfattning : Most strength grading machines on the European market use an averagemodulus of elasticity (MOE), estimated on a relatively large distance along awood member, as the indicating property (IP) to bending strength. Theaccuracy of such grading machines in terms of coefficient of determination israther low at R2 ≈ 0.5. LÄS MER