Sökning: "Stefan Jonsson"

Visar resultat 16 - 20 av 48 avhandlingar innehållade orden Stefan Jonsson.

1. 16. Development of a ferritic ductile cast iron for improved life in exhaust applications

   Författare :Madeleine Ekström; Stefan Jonsson; Pamela Henderson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material development; SiMo51; HK30; exhaust manifolds; high-temperature corrosion; high-temperature low-cycle fatigue;

   Sammanfattning : Due to coming emission legislations, the temperature is expected to increase in heavy-duty diesel engines, specifically in the hot-end of the exhaust system affecting components, such as exhaust- and turbo manifolds. Since the current material in the turbo manifold, a ductile cast iron named SiMo51, is operating close to its limits there is a need for material development in order to maintain a high durability of these components. LÄS MER

3. 17. Oxidation and corrosion fatigue aspects of cast exhaust manifolds

   Författare :Madeleine Ekström; Stefan Jonsson; Ulf Olofsson; Babette Tonn; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cast exhaust manifolds; high-temperature corrosion; high-temperature low-cycle fatigue; high-temperature corrosion fatigue; ductile cast irons; cast stainless steel; Materials Science and Engineering; Teknisk materialvetenskap;

   Sammanfattning : Emission regulations for heavy-duty diesel engines are becoming increasingly restrictive to limit the environmental impacts of exhaust gases and particles. Increasing the specific power output of diesel engines would improve fuel efficiency and greatly reduce emissions, but these changes could lead to increased exhaust gas temperature, increasing demands on the exhaust manifold material. LÄS MER

4. 18. Effects of manufacturing chain on mechanical performance : Study on heat treatment of powertrain components

   Författare :Johan Fahlkrans; Arne Melander; Bengt Lindberg; Stefan Jonsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Heat treatment; case hardening; carburising; induction hardening; gas quenching; tempering; straightening; fatigue strength; contact fatigue; fracture mechanics; Industriell ekonomi och organisation; Industrial Economics and Management; Production Engineering; Industriell produktion; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : The increasing demands for lightweight designs with high strength call for improved manufacturing processes regarding heat treatment of steel. The manufacturing process has considerable potential to improve the mechanical performance and to obtain more reliable results with less variation. LÄS MER

5. 19. Evolution of artificial defects during shape rolling

   Författare :Mirjana Filipovic; Stefan Jonsson; Per-Olov Perä; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; shape rolling; wire rod rolling; artificial defects; defect evolution; surface cracks; porosity; FEM; high speed steel; stainless steel; Other materials science; Övrig teknisk materialvetenskap; Initiering och utveckling av defekter under spårvalsning;

   Sammanfattning : Very often defects are present in rolled products. For wire rods, defects are very deleterious since the wire rods are generally used directly in various applications. For this reason, the market nowadays requires wire rods to be completely defect-free. Any wire with defects must be rejected as scrap which is very costly for the production mill. LÄS MER

7. 20. Regimes of Hospitality : Urban Citizenship between Participation and Securitization – the Case of the Multiethnic French Banlieue

   Författare :Christophe Foultier; Stefan Jonsson; Magnus Dahlstedt; Irene Molina; Linköpings universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES;

   Sammanfattning : This thesis analyzes various local development policies in Europe’s big urban areas. Striving to understand the respective places accorded to the measures to increase the participation of the inhabitants on the one hand, and to improve for security and public peace in the context of social and territorial policies on the other, I examine how urban policies define models of urban citizenship. LÄS MER