Sökning: "Urban density"

Visar resultat 16 - 20 av 98 avhandlingar innehållade orden Urban density.

  1. 16. Electromagnetic Analysis of Hydroelectric Generators

    Författare :Martin Ranlöf; Urban Lundin; Georg Traxler-Samek; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Contra-rotating rotors; damping torque; damper winding; finite element method; hydroelectric generators; permeance model; pole shoe shape; rotational losses; single machine infinite bus; slot ripple; synchronizing torque; synchronous machines; voltage waveform.; Engineering physics; Teknisk fysik; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Hydropower maintains its position as the most important source of renewable electric energy in the world. The efficiency of large hydropower plants is unsurpassed, and after more than hundred years of development, the technology is mature and highly reliable. LÄS MER

  3. 17. Measurement and modelling of unbalanced magnetic pull in hydropower generators

    Författare :Mattias Wallin; Urban Lundin; Antero Arkkio; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Damper winding; eddy currents; field winding short circuit; finite element method; hydropower generator; parallel circuits; rotor eccentricity; salient poles; synchronous generators; synchronous machines; UMP; unbalanced magnetic pull.; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Hydropower research is often perceived to be an old and exhausted field of study but with ageing equipment and the need for more intermittent operation caused by an increased share of other renewable energy sources new challenges lie ahead.The main focus of this dissertation are the electromagnetic forces resulting from nonuniform air gap flux, whether it be caused by rotor eccentricity or a faulty field winding. LÄS MER

  4. 18. Proposing Combined Approaches to Remove ECG Artifacts from Surface EMG Signals

    Författare :Sara Abbaspour; Maria Lindén; Urban Wiklund; Mälardalens högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Electromyography (EMG) is a tool routinely used for a variety of applications in a very large breadth of disciplines. However, this signal is inevitably contaminated by various artifacts originated from different sources. LÄS MER

  5. 19. Controlled growth of hexagonal GaN pyramids and InGaN QDs

    Författare :Anders Lundskog; Erik Janzén; Urban Forsberg; Per-Olof Holtz; Lars-Erik Wernersson; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : Gallium-nitride (GaN) and its related alloys are direct band gap semiconductors, with a wide variety of applications. The white light emitting diode (LED) is of particular importance as it is expected to replace energy inefficient light bulb and hazardous incandescent lamps used today. LÄS MER

  7. 20. Time-resolved CVD of Group 13-Nitrides

    Författare :Polla Rouf; Henrik Pedersen; Urban Forsberg; Nathan O´brien; Ola Nilsen; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Group 13 nitrides (AlN, GaN and InN) and their alloys are semiconductor materials with a wide bandgap span covering from UV down to IR range. Their excellent electronic properties make them extremely attractive materials for light emitting diodes (LEDs) and different kind of transistor structures, especially high electron mobility transistors (HEMTs). LÄS MER