Search for dissertations about: "corona"

Showing result 1 - 5 of 100 swedish dissertations containing the word corona.

2. 1. Evaluating Resistance to Corona and Ozone in Polymeric Materials for High Voltage Outdoor Applications

   Author : Bin Ma; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ozone; housing material; nano-composite; corona; Outdoor insulation; composite insulation;

   Abstract : Resistance to corona discharges and ozone, the well known ageing factors for polymeric materials used in outdoor insulation, has been listed as being of great importance among twelve properties identified by CIGRE WG D1.14 – Material Properties for Non-ceramic Outdoor Insulation. READ MORE

4. 2. Electrical Charges on Polymeric Insulator Surfaces and their Impact on Withstand Performance

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

   Abstract : 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. READ MORE

5. 3. The coronal heating problem

   Author : Boris V. Gudiksen; Göran Scharmer; James Klimchuk; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Solen; Corona; Magneto hydro dynamik; Astronomy and astrophysics; Astronomi och astrofysik;

   Abstract : The heating of the solar corona has been investigated during four of decades and several mechanisms able to produce heating have been proposed. It has until now not been possible to produce quantitative estimates that would establish any of these heating mechanism as the most important in the solar corona. READ MORE

6. 4. Loss and recovery of hydrophobicity of polydimethylsiloxane after exposure to electrical discharges

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

   Abstract : 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. READ MORE

7. 5. Microwave Breakdown in Inhomogeneous Fields

   Author : Joel Rasch; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; corona; inhomogeneous fields; Microwave breakdown; multipactor;

   Abstract : Microwave breakdown continues to be a risk in many applications involving the transmission and reception of microwave frequency signals. Satellite communication is especially interesting from the research point of view because of the extreme costs, and limited testing possibilities. READ MORE