Sökning: "partial effect"

Visar resultat 1 - 5 av 498 avhandlingar innehållade orden partial effect.

  1. 1. Effect of Partial Screening on Runaway-Electron Dynamics

    Författare :Linnea Hesslow; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fokker-Planck equation; runaway electrons; tokamak; fusion; plasma physics;

    Sammanfattning : One of the essential results of kinetic plasma physics is the runaway phenomenon: sufficiently large electric fields can accelerate a fraction of an electron population to relativistic energies. While such runaway electrons are fundamentally interesting objects of study in astrophysical settings, they are also of great practical relevance to fusion research. LÄS MER

  2. 2. Electrical Characterization of Partial Discharge Resistant Enamel Insulation

    Författare :Tuan Anh Hoang; Chalmers University of Technology; []
    Nyckelord :Enamel wire insulation; dipolar polarization; charge injection; charge transport; chromium oxide; dc conductivity; partial discharge; twisted pair.; dielectric permittivity;

    Sammanfattning : Adjustable speed drives for rotating machines have become increasingly popular as they provide possibilities of smooth and accurate process control as well as for energy savings. In such systems, due to the fact that the voltage applied at terminals of motor windings is no longer purely sinusoidal but characterized by a high content of harmonics, the appearing electrical and thermal stresses yield premature failures of the winding insulation, mainly because of an increased partial discharge (PD) activity. LÄS MER

  3. 3. Detection of Partial Discharges at Fast Rising Voltages

    Författare :Thomas Hammarström; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Partial discharges; cavities; repetitive voltages; high dV dt.; square like voltages; short rise time; measurements;

    Sammanfattning : The present demand for higher efficiency and flexibility in the energy sector has ledto an increased use of power electronic generated waveforms as these allow energyconversion between different frequencies including DC. The generated waveformsare usually synthesized by so called Pulse Width Modulation (PWM) techniques,where the desired waveform is approximated by a number of square shaped pulseswith a short rise time. LÄS MER

  4. 4. Modelling of cavity partial discharges at variable applied frequency

    Författare :Cecilia Forssén; Roland Eriksson; Hans Edin; Peter H.F. Morshuis; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharges; measurements; modelling; variable frequency; cavities; disc-shaped; polycarbonate; Electric power engineering; Elkraftteknik;

    Sammanfattning : The presence of partial discharges (PD) in high voltage components is generally a sign of defects and degradation in the electrical insulation. To diagnose the condition of high voltage insulation, PD measurements is commonly used. LÄS MER

  5. 5. The Competition for Forest Raw Materials in the Presence of Increased Bioenergy Demand : Partial Equilibrium Analysis of the Swedish Case

    Författare :Elina Bryngemark; Patrik Söderholm; Anne Toppinen; Luleå tekniska universitet; []
    Nyckelord :SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; bioenergy; biodiversity; partial equilibrium model; forest raw materials; market competition; Sweden; Economics; Nationalekonomi;

    Sammanfattning : Growing energy use and greenhouse gas emissions have implied an increased attention to the development of renewable energy sources. Bioenergy from forest biomass is expected to be one of the cornerstones in reaching renewable energy targets, especially in forest-rich countries such as Sweden. LÄS MER