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Showing result 1 - 5 of 1207 swedish dissertations matching the above criteria.

  2. 1. Differential railway track settlement in a transition zone – Field measurements and numerical simulations

    Author : Kourosh Nasrollahi; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fibre Bragg grating sensors; dynamic vehicle–track interaction; heavy haul traffic; non-linear track model; 3MB slab track; Transition zone; empirical settlement model; condition monitoring;

    Abstract : In a transition zone between two different railway track forms, there is a discontinuity in track structure leading to a gradient in track stiffness. Examples include transitions between different superstructures, e.g., slab track to ballasted track, and/or between different substructures, e. READ MORE

  4. 2. Detection of Partial Discharges at Fast Rising Voltages

    Author : Thomas Hammarström; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Partial discharges; cavities; repetitive voltages; high dV dt.; square like voltages; short rise time; measurements;

    Abstract : 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. READ MORE

  5. 3. Submerged Transmission in Wave Energy Converters : Full Scale In-Situ Experimental Measurements

    Author : Erland Strömstedt; Mats Leijon; Hans Bernhoff; Jan-Olov Aidanpää; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wave energy converter; direct drive; submerged transmission; piston rod; seal housing; sealing system; laser triangulation sensor; offshore measurements; relative displacement; vibrations; tilt angle; tilting; wear estimation.; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Abstract : Different wave power technologies are in development around the world in different stages of prototype testing. So far only a few devices have been deployed offshore at full scale for extended periods of time. Little data is published about how these different devices perform. READ MORE

  6. 4. Converter interactions in VSC-based HVDC systems

    Author : Georgios Stamatiou; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Symbolic eigenvalue expressions; Frequency Domain Analysis; Droop control; Net damping; VSC; Passivity Analysis; MTDC; Poor damping; HVDC;

    Abstract : The main objective of this thesis is to perform stability and control studies in the area of VSC-HVDC. A major part of the investigation focuses on the explanation of poorly-damped conditions and instability that are linked to dc-side resonances. READ MORE

  7. 5. Contact stiffness in tyre/road noise modelling and speed dependencies of tyre/road noise generation mechanisms

    Author : Julia Winroth; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tyre road noise; Air-pumping; Tyre road contact stiffness; Speed exponent analysis; Tyre road contact modelling;

    Abstract : Tools for simulating tyre/road noise are highly valuable in the efforts to limit the negative consequences of road traffic noise.A numerical tyre/road noise simulation tool was in this study used to investigate how the contact stiffness parameter affects the predicted tyre/road noise. READ MORE