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  • 1
    Electronic Resource
    Electronic Resource
    Modelling the structure of the softwood cell wall for computation of mechanical properties (1976)
    Springer
    Wood science and technology 10 (1976), S. 19-28 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A means to quantitatively construct two layer models of the wood cell-wall utilising basic density and mean microfibril angle data is discussed. It is assumed that the lignin distribution is uniform in the secondary wall layers, that there is a fixed polysaccharide ratio throughout the wall and that variation in wall thickness arises only from variation in S2 layer thickness. It is shown that the relative thickness of those cell wall layers in which the cellulose is transversely oriented (M+P, S1 and S3) have a significant effect on longitudinal shrinkage and that variance between computed and measured shrinkage values is reduced when compared with earlier models if both basic density and mean microfibril angle are taken into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376381
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  • 2
    Electronic Resource
    Electronic Resource
    Modelling moisture-related mechanical properties of wood Part I: Properties of the wood constituents (1978)
    Springer
    Wood science and technology 12 (1978), S. 75-86 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary By starting with simple concepts of the molecular structure and building up through the various levels of organisation in the wood cell wall it is possible to construct a model that simultaneously predicts the variation with moisture content change of both the longitudinal Young's modulus and longitudinal shrinkage of wood. To do this it is first necessary to define the stiffness and swelling characteristics of the lignin, hemicellulose and cellulose constituents of the wood as moisture content changes. It is suggested here that it is the bound fraction of the sorbed water that is responsible for the changes in swelling stress as well as for change in stiffness in the lignin and hemicellulose. The magnitudes of the stiffness of each of the constituents appear to be quite closely circumscribed by experimental values for longitudinal Young's modulus and shrinkage of wood and it is apparent that the stiffness characteristics of the in situ constituents are compatible with available experimental evidence for extracted lignin and hemicellulose and for native cellulose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390012
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  • 3
    Electronic Resource
    Electronic Resource
    Modelling moisture-related mechanical properties of wood Part II: Computation of properties of a model of wood and comparison with experimental data (1978)
    Springer
    Wood science and technology 12 (1978), S. 127-139 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Starting with simple concepts of the molecular structure and models of the stiffness and swelling behaviour of lignin, hemi-cellulose and cellulose and building up through the various levels of organisation in the wood cell wall a model has been constructed that simultaneously predicts the variation with moisture content change of both the longitudinal Young's modulus and longitudinal shrinkage of wood. The model closely predicts both longitudinal shrinkage and Young's modulus as they vary with the moisture content of the wood. The model also takes into account structural variations in the form of changes in cell wall layer thicknesses and mean cellulose microfibril orientation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350818
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  • 4
    Electronic Resource
    Electronic Resource
    The anisotropic elasticity of the plant cell wall (1968)
    Springer
    Wood science and technology 2 (1968), S. 268-278 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Die pflanzliche Zellwand wird im allgemeinen behandelt wie ein im wesentlichen aus zwei Phasen bestehendes Fasermaterial, bei dem die Fasern in einer isotropen Matrixsubstanz gelöst und in der Zellwandebene mit einem Winkel f(θ) verteilt sind. Sofern f(θ) normal verteilt ist, können die elastischen Konstanten der Zellwand verhältnismäßig einfach berechnet werden. Diese Theorie wird auf das Modell von Kiefern-Frühholz (Pinus radiata) angewendet, und die theoretisch ermittelte Änderung des longitudinalen Youngs Moduls mit der mittleren Faserrichtung wird mit experimentell bestimmten Werten verglichen.
    Notes: Summary The plant cell wall is treated as a two phase fibre composite material in which the fibres are dispersed, in an isotropic matrix, in the plane of the cell wall with an angular distribution f(θ). If f (θ) can be represented by a gaussian it is shown that the elastic stiffness constants of the cell wall can be easily evaluated. The theory is applied to a model of the earlywood of Pinus radiata and the theoretical variation of the longitudinal Young's Modulus with mean fibrilar direction is compared with that determined experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350273
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  • 5
    Electronic Resource
    Electronic Resource
    The longitudinal Young's modulus of Pinus radiata (1969)
    Springer
    Wood science and technology 3 (1969), S. 40-48 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Die Änderung des Young-Moduls in longitudinaler Richtung mit dem mittleren Winkel der Cellulose-Mikrofibrillen in der Frühholzsubstanz von Nadelholz wurde an kleinen, fehlerfreien Proben bestimmt. Der longitudinale Young-Modul fällt mit zunehmendem Winkel zwischen Längsachse und mittlerer Mikrofibrillen-Richtung in der Zellwand steil ab. Die Änderung wurde nach Form und Größe durch Anwendung der Elastizitätstheorie für ein faseriges Material mit wechselnden Faserrichtungen auf ein Modell aus dem Versuchsmaterial erklärt. Das Zwei-Phasen-Modell der Pflanzenzellwand wird damit bestätigt, soweit es sich um die elastischen Eigenschaften von starren, kristallinen Cellulose-Mikrofibrillen handelt, die in einer isotropen Matrix aus amorphem, parakristallinen Material eingebettet sind.
    Notes: Summary The variation of the longitudinal Young's modulus with mean cellulose microfibril angle of the wood substance of the earlywood of a softwood has been determined from small clear samples. The longitudinal Young's modulus falls steeply as the angle between the longitudinal axis and the mean microfibril direction in the cell walls increases. The variation has been explained in both form and magnitude by applying the elastic theory of a fibre composite material with distributed fibre directions to a model of the experimental material. It confirms the two phase concepts of the plant cell wall, as far as the elastic properties are concerned, of rigid crystalline microfibrils embedded in an isotropic matrix of amorphous and paracrystalline materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349983
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  • 6
    Electronic Resource
    Electronic Resource
    Theory of X-ray measurement of microfibril angle in wood (1997)
    Springer
    Wood science and technology 31 (1997), S. 143-152 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The property of fibre symmetry as exhibited by wood cellulose can be used to derive an explicit relationship between the orientation of a cellulose microfibril and the orientation of the X-ray beam diffracted by any of its crystallographic planes. The solution applies to a microfibril of any orientation and so is well suited to evaluating the microfibril angle distribution in wood containing cells of any cross-sectional shape. The (002) and (040) reflections of cellulose have complementary properties that could be exploited to enable current problems associated with the use of each individually for evaluating the mean microfibril angle of the S2 layer to be overcome. It is expected that it will be possible to measure the microfibril angle distribution throughout the whole cell wall and also measure the average cell cross-section of a wood sample, by analysing (002) and (040) diffraction profiles in conjunction with each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705881
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  • 7
    Electronic Resource
    Electronic Resource
    Theory of X-ray measurement of microfibril angle in wood (1997)
    Springer
    Wood science and technology 31 (1997), S. 225-234 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary A diffraction intensity function for material bodies composed of arrays of crystalline fibres such as occurs with the cellulose of wood has been derived. It is implied in the analysis that the crystalline fibres making up the body have fibre symmetry- that there is a tendency for groups of fibres to have one set of crystal axes parallel while in the orthogonal direction the axes assume a low degree of order. It is further assumed that the patterns of the angular arrangement of the fibre groups relative to one axis of the body is independent of the direction about that axis. These conditions are believed to be compatible with the cellulosic structure found in wood. Thus it becomes possible to calculate the expected diffraction intensity profiles of realistic (and therefore complex) models of wood. This has aided the interpretation of the reflections from the (040) crystal planes of cellulose which are contaminated by low level reflections from other crystal planes, and it has been found that it might be possible by conjoint analysis of the paratropic (002) reflections and the diatropic (040) reflections to measure the complete cell wall planar microfibril angle distribution and the shape of the cell wall cross-section.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702610
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  • 8
    Electronic Resource
    Electronic Resource
    A theory of the shrinkage of wood (1972)
    Springer
    Wood science and technology 6 (1972), S. 284-292 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary A relation describing the shrinkage properties of a fibre-composite is applied to a multilayered thin-walled model of wood. With the theory developed it is possible to specify shrinkage with respect to moisture content, as well as with factors involved in cell-wall geometry and composition. However, until more is known of the properties of the water-reactive matrix component of the composite it is only practicable to describe shrinkage with respect to the geometrical and compositional factors at the moisture-content of the stress free state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00357050
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  • 9
    Electronic Resource
    Electronic Resource
    Swelling of a fibre reinforced composite in which the matrix is water reactive (1972)
    Springer
    Wood science and technology 6 (1972), S. 157-161 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The swelling behaviour of an elastic fibre reinforced composite consisting of an inert fibrous phase embedded in a water reactive matrix is described. It is supposed that the addition of water causes the matrix to swell and become more compliant while the fibres passively resist the swelling stresses exerted by the matrix. A concise relation for the shrinkage or swelling strain is derived in terms of moisture content, the volume proportions of the phases, the overall elastic constants of the composite, the elastic constants of the matrix, and the moisture content at which the reinforcing elements are stress free.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350828
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  • 10
    Electronic Resource
    Electronic Resource
    Theory of X-ray measurement of microfibril angle in wood Part 2. The diffraction diagram X-ray diffraction by materials with fibre type symmetry (1997)
    Springer
    Wood science and technology 31 (1997), S. 225-234 
    Details
    ISSN: 0043-7719
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary A diffraction intensity function for material bodies composed of arrays of crystalline fibres such as occurs with the cellulose of wood has been derived. It is implied in the analysis that the crystalline fibres making up the body have fibre symmetry- that there is a tendency for groups of fibres to have one set of crystal axes parallel while in the orthogonal direction the axes assume a low degree of order. It is further assumed that the patterns of the angular arrangement of the fibre groups relative to one axis of the body is independent of the direction about that axis. These conditions are believed to be compatible with the cellulosic structure found in wood. Thus it becomes possible to calculate the expected diffraction intensity profiles of realistic (and therefore complex) models of wood. This has aided the interpretation of the reflections from the (040) crystal planes of cellulose which are contaminated by low level reflections from other crystal planes, and it has been found that it might be possible by conjoint analysis of the paratropic (002) reflections and the diatropic (040) reflections to measure the complete cell wall planar microfibril angle distribution and the shape of the cell wall cross-section.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002260050030
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