Sökning: "middle lamella"

Hittade 5 avhandlingar innehållade orden middle lamella.

  1. 1. Composition of lignin in outer cell-wall layers

    Författare :Maria Christiernin; Gunnar Henriksson; Gösta Brunow; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lignin; thioacidolysis; primary wall; middle lamella; Populus balsamifera; Populus tremula L. x P. tremuloides Michx.; Picea abies; Picea glauca; Cellulose and paper engineering; Cellulosa- och pappersteknik;

    Sammanfattning : The composition of lignin in the outer cell-wall layers of spruce and poplar has been studied and the data obtained have been compared with those of the mature reference wood in which the secondary cell wall predominates. Materials with exclusively or predominantly outer cell-wall layers were examined. LÄS MER

  3. 2. Ultrastructure of the wood cell wall

    Författare :Jonas Hafrén; KTH; []
    Nyckelord :;

    Sammanfattning : The ultrastructure of wood fibres has been studied incambial cells, differentiating fibres and mature xylem fibres,using the Rapid-Freeze Deep-Etching (RFDE) technique combinedwith transmission electron- and epifluorescence microscopy.Pectin distribution in mature wood fibres, and in fibres duringdevelopment, have been studied by immunolabelling. LÄS MER

  4. 3. Cell wall bulking and distribution of different chemicals in pine, Pinus Sylvestris

    Författare :Lennart Wallström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Träteknik; Wood Technology;

    Sammanfattning : The interaction between wood, Pinus sylvestris, (60% RH) and polyethyleneglycol (PEG) of different molecular weights (PEG 200 and PEG 1500), pentaerythritol and glycerol, impregnated into the wood, has been investigated using Scanning Electron Microscopy, EDS-analysis, dynamical mechanical techniques (DMTA), X-ray diffraction (WAXS) and macroscopic dimensional measurement. Reduced dimensional changes after impregnation when exposed to environments with changing moisture content, showed that the stabilization effect of glycerol and PEG 200 impregnation is very good. LÄS MER

  5. 4. Mechanical Pulp. Effects of Pretreatment and Wood Source on Fiber Separation and Pulp Properties

    Författare :Lars Johansson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; torsional stress; pulp properties; chips; impregnation; screw press; SEM; mechanical pulp; sulfonation; shear stress; fracture surface; wood quality; temperature;

    Sammanfattning : The work presented in this thesis concerns the mechanical pulping process and the effects of wood source and pretreatment conditions on the pulp properties. In the first part, the deformation of Norway spruce (Picea abies) wood samples was investigated under shear and torsional loading at different temperatures (20-95°C) and sulfonation conditions. LÄS MER

  7. 5. Physicochemical properties of root fiber suspensions. A comparison between parsnip (Pastinaca sativa) and yacon (Smallanthus sonchifolius)

    Författare :Alejandra Castro; Avdelningen för livsmedel och läkemedel; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; physicochemical properties; parsnip; yacon; plant suspensions; particle size distribution; rheology; fructans; dietary fiber;

    Sammanfattning : The physicochemical properties of two root suspensions, parsnip (Pastinaca sativa) and yacon (Smallanthus sonchifolius), were studied and compared at different concentrations and after being subjected to processes such as homogenization and heating. The study and the evaluation of the physicochemical properties of these plant materials in the form of pastes might help to increase the interest in these two roots, and possibly encourage their further industrial use. LÄS MER