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Visar resultat 1 - 5 av 114 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Iron Losses in Electrical Machines - Influence of Material Properties, Manufacturing Processes, and Inverter Operation

   Författare :Andreas Krings; Juliette Soulard; Oskar Wallmark; Annette Mütze; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; AC machines; cobalt-iron; eddy current losses; electrical steel sheets; inverter-fed machines; iron alloys; iron loss measurements; machine design; magnetic hysteresis; magnetic losses; magnetic materials; nickel-iron; permanent magnet machines; silicon-iron; soft magnetic composites; slot-less machines; soft magnetic materials; thermal effects.; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : As the major electricity consumer, electrical machines play a key role for global energy savings. Machine manufacturers put considerable efforts into the development of more efficient electrical machines for loss reduction and higher power density achievements. LÄS MER

3. 2. Thermodynamic and kinetic properties of Fe-Cr and TiC-ZrC alloys from Density Functional Theory

   Författare :Vsevolod Razumovskiy; Pavel Korzhavyi; Andrei Ruban; Malin Selleby; Sergei Dudarev; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio; first principles; point defects; vacancy clusters; alloys; steels; iron; carbides; diffusion; phase diagram; density functional theory; elastic constants; elastic properties; thermodynamic modelling;

   Sammanfattning : The complete and accurate thermodynamic and kinetic description of any systemis crucialfor understanding and predicting its properties. A particular interest is in systemsthat are used for some practical applications and have to be constantly improved usingmodification of their composition and structure. LÄS MER

4. 3. On the hot crack formation during solidification of iron-base alloys

   Författare :Karin Hansson; KTH; []
   Nyckelord :hot cracking; hot tearing; cracking fracturing ; tearing; ductility; brittleness; embrittlement; fractures; ductile brittle transition; solidification; iron; copper; nickel; Invar; steels; free machining steels; stainless steels; penetration; crack;

   Sammanfattning : Hot cracking during solidification is a severe problem inmany casting processes, for example in continuous casting.Combinations of low strength and low ductility of the materialat high temperatures and applied tensile stress can cause hotcracking. LÄS MER

5. 4. Microscopy of high temperature oxidation of iron and some stainless steels

   Författare :Torbjörn Jonsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; water vapour; sulphur dioxide; FIB; X20; stainless steel; 353MA; EDX; KCl; FIB SEM; SEM; microstructure; TEM; iron; High-temperature oxidation; in-situ ESEM;

   Sammanfattning : This thesis concerns the high temperature oxidation of iron and some stainless steels. The oxide scales, as well as the subjacent metal, were investigated using a range of electron and ion microscopy techniques, including SEM, TEM, EDX and FIB. The aim was to link the microstructural observations to the oxidation mechanisms of the materials. LÄS MER

7. 5. Mechanisms of Metal Dusting

   Författare :Peter Szakálos; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; metal dusting; mechanism; driving force; kinetics; high temperature corrosion; carburization; stainlesssteel; Ni-base alloys; iron; alumina formers; FeCrAl; oxidation; carbon nanotubes; discontinuous precipitation; Materials science; Teknisk materialvetenskap;

   Sammanfattning : The primary intention with this Doctoral thesis is to fillin the knowledge gaps and raise the level of understandingregarding the different metal dusting mechanisms in general andexplain the process in detail for high alloyed materials.Considerable effort is put into identifying the driving forcesand elucidating the diffusional processes in metal dusting. LÄS MER