Search for dissertations about: "Spark discharge"

Showing result 1 - 5 of 20 swedish dissertations containing the words Spark discharge.

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

    Author : Liliana Arevalo; Vernon Cooray; Dan Windmar; Uppsala universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  4. 2. Theoretical and Experimental Studies of the Formation of Ionized Gases in Spark Ignition Engines

    Author : Raymond Reinmann; Förbränningsfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Thermal Ionization; Calorimetry; Interferometry; Spark Ignition Engine; Current and Voltage Measurements; Engine Control.; fluid dynamics; Gases; plasmas; Gaser; plasma; fluiddynamik; Breakdown; Arc; Glow; Flame Ionization; Chemi-Ionization; Spark; Townsend; Fysicumarkivet A:1998:Reinmann;

    Abstract : The processes that govern the formation, existence and consumption of ions in gases have been studied both experimentally and theoretically. The aim of the work is targeted at increasing the understanding of these phenomena in the working gases inside an engine. READ MORE

  5. 3. Experimental Studies of Advanced Ignition Systems for Lean Burn Natural Gas Engines

    Author : Jessica Dahlström; Förbränningsmotorer; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ignition system; spark energy; internal combustion engine; engine; spark ignition; natural gas;

    Abstract : One of the greatest challenges for the transport sector today is reducing its environmental impact. This applies especially to the emission aspects, much due to increasingly stringent emissions legislations. READ MORE

  6. 4. Enhanced Active Resonant DC Circuit Breakers for HVDC Grids

    Author : Tim Augustin; Hans-Peter Nee; Marley Becerra; Jürgen Biela; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Active damping; Actuator; DC circuit breakers; DC grid; DC power systems; Fast mechanical switch; Fault handling strategy; Gas discharge devices; HVDC; HVDC circuit breakers; Multilevel converters; Multiterminal HVDC; Power transmission; Spark gaps; Thomson-coil actuator; Vacuum interrupter; Voltage Source Converter VSC ; Electrical Engineering; Elektro- och systemteknik;

    Abstract : High-voltage DC (HVDC) grids are considered promising for the electricity grid expansion required to integrate renewable energy sources into the existing infrastructure. DC fault currents increase rapidly and lack a current zero crossing. READ MORE

  7. 5. Aerosol Metal Nanoparticles and their Role in Particle-Assisted Growth of III–V Nanowires

    Author : Robert Hallberg; NanoLund: Centre for Nanoscience; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aerosol formation; III–V semiconductor materials; catalyst particles; Palladium nanoparticles; Gold nanoparticles; Spark discharge generation; MOVPE; MOCVD; Transmission electron microscopy TEM ; Phase stability; Nanoparticle deposition; Nanoparticle generation; nanoparticles characterization; Nanowire NW ; Nanowire growth;

    Abstract : Semiconductor nanowires have properties that make them potentially useful for applications in future electronic, photovoltaic, and optoelectronic devices. A powerful nanowire fabrication technique is the use of a nanoparticle as a preferential nucleation site, from which a nanowire grows. READ MORE