Sökning: "outdoor insulation"

Visar resultat 21 - 25 av 32 avhandlingar innehållade orden outdoor insulation.

  1. 21. Electrical Charges on Polymeric Insulator Surfaces and their Impact on Withstand Performance

    Författare :Sarath Kumara; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; impulse corona; Surface charge; impulse flashover voltage; corona charging; streamer criterion; surface potential decay; charge relaxation;

    Sammanfattning : Use of polymeric materials for high voltage outdoor insulation systems is increasing continuously. Insulating polymers gradually replace traditional materials like porcelain and glass and become dominant at ultra high voltages, e.g., in 1000 kV ac and 800 kV dc overhead power transmissions, which are presently being developed. LÄS MER

  3. 22. Moisture Conditions in Exterior Wooden Walls and Timber During Production and Use

    Författare :Lars Olsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; laboratory test; MRD-index; moisture; driving rain; hysteresis; wood; precipitation; timber; weather barrier; mould growth; façade; wall; wind barrier; measurement; field test; mold;

    Sammanfattning : Thermal insulation of building envelopes has improved over the years. This means that building envelope have become more susceptible to defects, with an increased risk of moisture damage. The criteria for energy consumption have become more rigorous, but the shift should not lead to moisture problems. LÄS MER

  4. 23. Inhibited electrical discharges in air

    Författare :Anders Larsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; elektronik; Electronics;

    Sammanfattning : Modem society requires a stable electricity supply, the reliability of which is partlydetermined by the dielectric strength of the outdoor high-voltage insulation systems.This thesis concentrates upon one particular discharge phenomenon that occurs whensuch a system is subjected to rain, namely the inhibited discharge. LÄS MER

  5. 24. Identification and evaluation of slip and fall risk on ice and snow

    Författare :Chuansi Gao; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Industrial Work Environment; Industriell produktionsmiljö;

    Sammanfattning : Roads and pavements covered with ice and snow during winter in the Nordic and other cold regions are slippery, which result in the prevalence of slip and fall accidents among not only the public, but also outdoor workers. Literature and injury statistics revealed that the most frequently specified contributory factor for occupational slip, trip and fall accidents in Sweden is snow and ice. LÄS MER

  7. 25. Loss and recovery of hydrophobicity of polydimethylsiloxane after exposure to electrical discharges

    Författare :Henrik Hillborg; KTH; []
    Nyckelord :silicone rubber; polydimethysiloxane; dydrophobicity; corona; air-plasma; oxygen-plasma; surface characterisation;

    Sammanfattning : Silicone rubber based on polydimethylsiloxane is used ashigh voltage outdoor insulation, due to its ability to preservethe hydrophobic surface properties during service and evenregain hydrophobicity after exposure to electrical discharges.The underlying processes for the hydrophobic recovery arediffusion of low molar mass siloxanes from the bulk to thesurface and reorientation by conformational changes ofmolecules in the surface region. LÄS MER