Sökning: "frictional resistance"

Visar resultat 1 - 5 av 19 avhandlingar innehållade orden frictional resistance.

1. 1. The Enemy Below - Adhesion and Friction of Ship Hull Fouling

   Författare :Dinis Oliveira; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ship resistance; in-water hull cleaning; roughness; biofouling; hull grooming; frictional resistance; adhesion strength; turbulent boundary layer; hull form factor;

   Sammanfattning : Below the waterline, commercial ships are good targets for marine organisms to attach and proliferate, a problem commonly known as biofouling. A fouled hull means higher hydrodynamic resistance, which can result in significant fuel penalties. LÄS MER

3. 2. Electrical and Frictional Performance of Tin-Coated Contacts Exposed to Wear and Fretting Corrosion

   Författare :Tag Hammam; Åke Öberg; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Friction; Fretting; Wear; Contact resistance; Tin; Connectors; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Sammanfattning : The complexity of electronic systems in vehicles is rapidly increasing, and as a consequence, the long-term reliability of automotive connectors has become an important issue. The aims of this thesis have been: 1. to characterize the friction, wear and electrical properties of tin coatings, 2. LÄS MER

4. 3. Synthesis, Characterization, and Evaluation of Ag-based Electrical Contact Materials

   Författare :Fang Mao; Ulf Jansson; Mikael Olsson; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electrical contact; bulk; coating; Ag-based alloys; Ag-based delafossite; AgI; graphene; graphene oxide; combinatorial material science; dc magnetron sputtering; friction; wear; hardness; contact resistance;

   Sammanfattning : Ag is a widely used electrical contact material due to its excellent electrical properties. The problems with Ag are that it is soft and has poor tribological properties (high friction and wear in Ag/Ag sliding contacts). LÄS MER

5. 4. Fiber push-out testing of sapphire fiber alumina matrix composites

   Författare :David Le Pagne; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material Mechanics; Materialmekanik;

   Sammanfattning : A current area of international research and development concerns composite materials consisting of oxides reinforced with continuous oxide fibers. These materials have an inherent resistance to oxidation and therefore have potential as structural materials for applications at extremely high temperatures. LÄS MER

7. 5. The Hydrodynamics of Waterjet/Hull Interaction

   Författare :Arash Eslamdoost; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; trim angle; vena-contracta; transom clearance; net thrust; waterjet hull interaction; waterjet propulsion; capture area; exit drag; non-linear free-surface; intake drag; gross thrust; sinkage; streamtube; RANS; thrust deduction; potential flow; VOF;

   Sammanfattning : The objective of the present investigation is to explore the physics behind the waterjet/hull interaction, and in particular the negative thrust deduction often reported in the semi-planing speed range. Another objective is to propose a validated numerical technique for computing the hydrodynamics of waterjet-driven hulls. LÄS MER