Sökning: "Staffan Jacobson"

Visar resultat 6 - 10 av 26 avhandlingar innehållade orden Staffan Jacobson.

  1. 6. On the Nature of Cemented Carbide Wear in Rock Drilling

    Författare :Ulrik Beste; Staffan Jacobson; Mikael Olsson; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; cemented carbide; wear; rock drilling; rock; Materialvetenskap; Materials science; Teknisk materialvetenskap;

    Sammanfattning : WC/Co cemented carbide is a composite material for highly demanding wear applications. The unique combination of hardness (from the WC-phase) and toughness (from the binder Co) gives a material especially suitable for rock drilling. LÄS MER

  3. 7. Protective Tribofilms on Combustion Engine Valves

    Författare :Robin Elo; Staffan Jacobson; Mikael Åstrand; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Internal combustion engine; valve; sealing surface; tribofilm; oil residue; test rig; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

    Sammanfattning : Inside the complex machinery of modern heavy-duty engines, the sealing surfaces of the valve and valve seat insert have to endure. Right next to the combustion, temperatures are high and high pressure deforms the components, causing a small relative motion in the interface. LÄS MER

  4. 8. Combustion Valve Wear : A Tribological Study of Combustion Valve Sealing Interfaces

    Författare :Peter Forsberg; Staffan Jacobson; Rob Dwyer-Joyce; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Combustion valves; wear; tribofilm; test rig; combustion residue; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

    Sammanfattning : The exhaust valve system of combustion engines experiences a very complex contact situation of frequent impact involving micro sliding, high and varying temperatures, complex exhaust gas chemistry and possible particulates, etc. In addition, the tribological situation in the exhaust valve system is expected to become even worse due to strict future emission regulations, which will require enhanced combustion and cleaner fuels. LÄS MER

  5. 9. Tribology of Metal-Graphite Composites : A Study of Sliding Electrical Contact Surfaces

    Författare :Martina Grandin; Wiklund Urban; Staffan Jacobson; Ulf Jansson; Christian Holzapfel; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tribology; tribofilm; surface analysis; wear; friction; electrical contacts; metal-graphite; contact resistance; cross-section; nanocomposite coating; copper; silver; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

    Sammanfattning : An environmentally sustainable production of electrical power is important for preserving the earth’s natural resources. In order to utilize this power as efficiently as possible, it is of great importance to minimize the losses, for example in sliding electrical contacts. LÄS MER

  7. 10. Triboactive Component Coatings : Tribological Testing and Microanalysis of Low-Friction Tribofilms

    Författare :Fredrik Gustavsson; Staffan Jacobson; Bojan Podgornik; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tribofilms; low-friction coatings; tungsten disulfide; TEM; Materialvetenskap; Materials Science;

    Sammanfattning : Coatings are often used on critical components in machines and engines to reduce wear and to provide low friction in order to reduce energy losses and the environmental impact.A triboactive coating not only provides this desired performance, it also actively maintains the low friction by a structural or chemical change in a very thin top layer of these already micrometer thin coatings. LÄS MER