Sökning: "negative discharge"

Visar resultat 1 - 5 av 95 avhandlingar innehållade orden negative discharge.

  1. 1. Numerical Simulations of Long Spark and Lightning Attachment

    Författare :Liliana Arevalo; Vernon Cooray; Dan Windmar; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; breakdown; discharge; leader channel; lightning attachment; negative discharge; positive discharge; streamer; Electrical engineering; Elektroteknik; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : The research work presented here is concerned with numerical simulations of two different electrical phenomena: Long gap electrical discharges under switching impulses and the lightning attachment process associated with positive upward leaders. The development of positive upward leaders and the progression of discharges in long gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. LÄS MER

  3. 2. Computer Modelling of Electrophysical Phenomena in High Voltage Insulation

    Författare :Yuriy Serdyuk; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric properties; discharge plasma; composite material; computer model; numerical simulations; electrical discharge;

    Sammanfattning : Different kinds of dielectrics are used for high voltage insulation. In most of the cases, they are combined into complex insulating systems forming macro- and micro-scale composite structures. LÄS MER

  4. 3. Hindrances and Feasibilities that Affect Discharge Planning : Perspectives Before and After the Development and Testing of ICT Solutions

    Författare :Sofi Nordmark; Eva Lidén; Luleå tekniska universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Nursing; Omvårdnad;

    Sammanfattning : Deficits in collaboration and information exchange during patient discharge from the hospital can cause negative consequences for the patient, such as delayed discharge, readmission, inadequate post-discharge care, and reduced quality of life. Information and communication technology (ICT) can contribute to easing and securing information exchange and collaboration at care transitions from one care provider to another. LÄS MER

  5. 4. Si negative electrodes for Li-ion batteries : Aging mechanism studies by electrochemistry and photoelectron spectroscopy

    Författare :Fredrik Lindgren; Fredrik Björefors; Kristina Edström; Anna Andersson; Miguel Ángel Muñoz; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis is focusing on the challenges when using Si as a possible new negative electrode material in Li-ion batteries. The overall aim is to contribute to a general understanding of the processes in the Si electrode, to identify aging mechanisms, and to evaluate how they influence the cycling performance. LÄS MER

  7. 5. Partial Discharge Analysis at Arbitrary Voltage Waveform Stimulus

    Författare :Xiaolei Wang; Hans Edin; Elisabeth Lindell; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Partial discharge (PD) detection is widely used to diagnose the defects and degradation in an electrical insulation system. Generally, PD are measured with 50 Hz AC sinusoidal voltage in the on-line situation, but can also be detected at other voltage stimulus in some off-line situations. LÄS MER