Search for dissertations about: "Electric arc"

Showing result 21 - 25 of 47 swedish dissertations containing the words Electric arc.

  2. 21. Studies on Current Commutation in Hybrid DC-breakers

    Author : Jesper Magnusson; Göran Engdahl; Magne Runde; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Commutation; Hybrid DC-breakers; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Compared to conventional AC-circuit breakers, a DC-breaker has to act fast and force the current down to zero. Many different DC-breaker topologies are available, and this thesis is focused on the hybrid DC-breaker comprising a mechanical switch and high power semiconductors. READ MORE

  4. 22. The use of LCA for the environmental evaluation of the recycling of galvanized steel

    Author : Christina Viklund-White; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Process Metallurgy; Processmetallurgi;

    Abstract : The goal for this project was to build and spread knowledge about the use of LCA in the metallurgical industry, as well as to evaluate the use of LCA within the metallurgical industry in general, particularly for the management of waste- and by-products. For this, the assessment of the recycling of zinc coated scrap to an electric arc furnace was considered as a suitable case study. READ MORE

  5. 23. Solitary waves and enhanced incoherent scatter ion lines

    Author : Jonas Ekeberg; Lars Eliasson; Kristof Stasiewicz; Jan Trulsen; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; plasma waves and instabilities; nonlinear phenomena; solitons and solitary waves; ionosphere; Sun: corona; incoherent scatter radar; MHD; plasmavågor och instabiliteter; ickelinjära fenomen; solitoner och solitära vågor; jonosfär; solen: korona; inkoherent spridningsradar; MHD; Geocosmophysics and plasma physics; Geokosmofysik och plasmafysik; Space physics; Rymdfysik; Plasma physics; Plasmafysik; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos; fysik; Physics; rymd- och plasmafysik; Space and Plasma Physics;

    Abstract : This thesis addresses solitary waves and their significance for auroral particle acceleration, coronal heating and incoherent scatter radar spectra. Solitary waves are formed due to a balance of nonlinear and dispersive effects. READ MORE

  6. 24. Multi-spectral analysis of fine scale aurora

    Author : Hanna Dahlgren; Göran Marklund; Nickolay Ivchenko; Fred Sigernes; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Plasma physics; Plasmafysik; Optics; Optik;

    Abstract : The Aurora Borealis is the visible manifestation of the complex plasma interaction between the solar wind and the Earth's magnetosphere and ionosphere. Ground based and in situ measurements demonstrate a prevalence of dynamic fine structure within auroral displays, with spatial scales down to tens of metres and time variations occurring on a fraction of a second. READ MORE

  7. 25. Studies on Carbothermic Reduction of Chromite in the Presence of FeOx

    Author : Xianfeng Hu; Yongxiang Yang; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Process Metallurgy; Processmetallurgi;

    Abstract : Direct chromium alloying by chromite ore is a promising technology for producing Crcontainingsteels, as the ferrochrome production process and the chromium alloying processare integrated into a single step, which has the potential of saving energy and raw materials.In this work Thermogravimetric Analysis experiments and induction furnace experiments (upto 80-kg scale) have been carried out to investigate the carbothermic reduction process ofchromite in the presence of FeOx (iron, mill scale or magnetite). READ MORE