Sökning: "tower"

Visar resultat 21 - 25 av 86 avhandlingar innehållade ordet tower.

  1. 21. Resistance of Circular and Polygonal Steel Towers for Wind Turbines : Down scale component experiments and Finite element analysis

    Författare :Anh Tuan Tran; Florea Dinu; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel Structures; Stålbyggnad;

    Sammanfattning : With increasing demand of sustainable energy production, the harvesting of wind power by using wind turbines have become increasingly important over the last few decades. Most of the wind turbine towers are made from steel. Towers are an important part of the investment in wind parks and contribute about 20% of costs for the onshore towers. LÄS MER

  3. 22. Noise from wind turbines

    Författare :Olivier Fégeant; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; masking; vibration transmission; diffraction; ambient noise; pseudo-noise; cylindrical shell. Perturbation methods; structural mobility; axoustic outdoor measurement; Building engineering; Byggnadsteknik;

    Sammanfattning : A rapid growth of installed wind power capacity is expectedin the next few years. However, the siting of wind turbines ona large scale raises concerns about their environmental impact,notably with respect to noise. LÄS MER

  4. 23. Dualities, Symmetries and Unbroken Phases in String Theory : Probing the Composite Nature of the String

    Författare :Johan Engquist; Joseph Minahan; Charlotte Kristjansen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Theoretical Physics; String Theory; M-Theory; Higher Spin Gauge Theory; Super Yang-Mills Theory; Anti-de Sitter Spacetime; Singletons; Massless Higher Spin Gauge Fields; AdS CFT Correspondence; Spin Chains; Semiclassical Strings; Tensionless Limits; Conformal Symmetry; Supersymmetry; Higher Spin Gauge Symmetry; Integrability; Fysik; Physics; Fysik;

    Sammanfattning : The thesis treats aspects of string/M-theory in anti-de Sitter spacetimes and their supersymmetric completions. By applying the AdS/CFT correspondence, as well as models of spin chains and singletons, we try to attain a better understanding of the underlying symmetries and the unbroken phases of string/M-theory. LÄS MER

  5. 24. Friction connections with slotted holes for wind towers

    Författare :Wylliam Husson; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel Structures; Stålbyggnad;

    Sammanfattning : In a constantly increasing and competitive market the efficiency of the whole wind power plant is an issue. The tubular steel towers supporting wind turbines account for about 15 to 20% of the total installation costs and their optimization may lead to substantial savings with regard to costs and use of material. LÄS MER

  7. 25. Temporal Characteristics of Boreal Forest Radar Measurements

    Författare :Albert Monteith; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; antenna array; Synthetic aperture radar; temporal coherence; tomography; backscatter; remote sensing;

    Sammanfattning : Radar observations of forests are sensitive to seasonal changes, meteorological variables and variations in soil and tree water content. These phenomena cause temporal variations in radar measurements, limiting the accuracy of tree height and biomass estimates using radar data. LÄS MER