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Visar resultat 1 - 5 av 49 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Activity concentrations of radionuclides in energy production from peat, wood chips and straw

    Författare :Robert Hedvall; Kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radionuclides; peat; wood; chips; straw; bioenergy; biomass; district heating; emission; Cs; Physics; Chernobyl; Radioactivity; Fysik; Technological sciences; Teknik; Fysicumarkivet A:1997:Hedvall;

    Sammanfattning : In this thesis quantitative analyses of radionuclide concentrations in bioenergy fuels such as peat, wood chips and straw are presented. For comparison a brief description is included of radionuclide concentrations and radiation doses from other sources of power and also from some industrial applications. LÄS MER

  3. 2. Aerosol Particle Sources Affecting the Swedish Air Quality at Urban and Rural Level

    Författare :Adam Kristensson; Kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; wood combustion; traffic; long distance transport; nucleation; urban; background; PM2.5; PM10; source contribution; PIXE; Physics; Environmental technology; Fysik; pollution control; emissions; Aerosol particle; sources; Miljöteknik; kontroll av utsläpp; size distribution; Fysicumarkivet A 2005:Kristensson;

    Sammanfattning : During the last decades anthropogenic aerosol particles have attracted much attention due to their adverse health effects and their influence of climate change, and in Sweden, there are mainly three aerosol sources that affect the air quality; domestic wood combustion, traffic, and long distance transport, which includes new particle formation. This work concerns the characterization of these sources and an estimate of how much they contribute to the aerosol particle number (ToN) and mass concentrations (PM) in Swedish cities and at background locations. LÄS MER

  4. 3. Electromagnetic Modelling for the Estimation of Wood Parameters

    Författare :Therese Sjödén; Sven Nordebo; Börje Nilsson; Andreas Fhager; Växjö universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cramér Rao bound; electromagnetic modelling; estimation; grain angle; microwave; wood properties.; Cramér Rao-gräns; elektromagnetisk modellering; estimering; fibervinkel; mikrovågor; träegenskaper.; Engineering physics; Teknisk fysik; Physics; Fysik;

    Sammanfattning : Spiral grain in trees causes trouble to the wood industry, since boards sawn from trees with large grain angle have severe problems with form stability. Measurements of the grain angle under bark enable the optimisation of the refining process. LÄS MER

  5. 4. Microwave treatment of wood

    Författare :Lars Hansson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wood Physics; Träfysik;

    Sammanfattning : Drying wood using microwave energy is not very common, but could be a complement to conventional air-circulation drying due to the possibility to dry wood faster than the conventional drying methods with preserved quality. Furthermore, this technique could be used to condition boards with too high moisture content gradient. LÄS MER

  7. 5. Properties of solid wood : responses to drying and heat treatment

    Författare :Margot Sehlstedt-Persson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wood Physics; Träfysik;

    Sammanfattning : The hygro-thermal processes that wood is exposed to during drying and heat treatment lead to different reactions or responses in the wood material. The objective of this thesis has been to study the impact of different drying and heat-treatment strategies on various responses, such as strength, sorption/desorption behaviour, dimensional stability and colour changes. LÄS MER