Avancerad sökning

Hittade 3 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Computational electromagnetics : software development and high frequency modeling of surface currents on perfect conductors

    Författare :Sandy Sefi; Jesper Oppelstrup; Francisco Saez de Adana; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; High frequency approximations; Maxwell’s equations; Method of Moments; Physical Optics; Geometrical Theory of Diffraction; Extraction Extrapolation; Numerical analysis; Numerisk analys;

    Sammanfattning : In high frequency computational electromagnetics, rigorous numerical methods be come unrealistic tools due to computational demand increasing with the frequency. Instead approximations to the solutions of the Maxwell equations can be employed to evaluate th electromagnetic fields. LÄS MER

  3. 2. Wind-wave interaction effects on offshore wind energy

    Författare :Ali Al Sam; Strömningsteknik; []
    Nyckelord :wind-wave; swell; atmospheric boundary layer; marine atmospheric boundary layer; atmospheric turbulence; Large-eddy simulation; actuator line; wind sea; offshore technology; wind energy; wind turbine; aerodynamic;

    Sammanfattning : This thesis is devoted to the investigation of the impacts of fast moving ocean surface waves on the aerodynamics of offshore wind turbines. The impacts of non-locally generated waves (swell) on the Marine Atmospheric BoundaryLayer (MABL) and thereby on offshore wind turbine aerodynamics are studied numerically by using Large Eddy Simulations and the Actuator Line Method. LÄS MER

  4. 3. Long-term performance of poly(vinyl chloride) cables : mechanical and electrical performances and the effect of plasticizer migration

    Författare :Maria Ekelund; Ulf W. Gedde; Minna Hakkarainen; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Poly vinyl chloride cables; ageing; mechanical properties; plasticizer migration; Polymer chemistry; Polymerkemi;

    Sammanfattning : Cables insulated with plasticized poly(vinyl chloride) were aged at temperatures between 80 and 180 °C in air and their conditions were assessed by indenter modulus measurements, tensile testing, infrared (IR) spectroscopy, differential scanning calorimetry (DSC) and liquid chromatography (HPLC). Electrical testing of oven-aged cable samples was performed in order to relate the electrical functionality during a high-energy line break accident to the mechanical properties and to establish a lifetime criterion. LÄS MER