Search for dissertations about: "In-situ contact resistance."

Showing result 1 - 5 of 16 swedish dissertations containing the words In-situ contact resistance..

  2. 1. On Gas Contaminants, and Bipolar Plates in Proton Exchange Membrane Fuel Cells

    Author : Yasna Acevedo Gomez; Carina Lagergren; Göran Lindbergh; Rakel Wreland Lindström; Qinfeng Li; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PEM fuel cell; contaminants; ammonia; nitrogen dioxide; degradation; recovery; bipolar plates; electroplating; Ni-Mo; Ni-Mo-P; internal contact resistance; PEM bränslecell; föroreningar; ammoniak; kvävedioxid; degradering; återhämtning; bipolära plattor; elektroplätering; Ni-Mo; Ni-Mo-P; interna kontaktmotståndet; Chemical Engineering; Kemiteknik;

    Abstract : The proton exchange membrane (PEM) fuel cell is an electrochemical device that converts chemical energy into electrical energy through two electrocatalytic reactions. The most common catalyst used is platinum on carbon (Pt/C), which has shown the best performance in the fuel cell until now. READ MORE

  4. 2. Development of characterisation methods for the components of the polymer electrolyte fuel cell

    Author : Jari Ihonen; KTH; []
    Keywords : polymer electrolyte membrane fuel cell; contacct resistance; clamping pressure; stainless steel; membrane degradation;

    Abstract : In this work characterisation methods and fuel cell hardwarewere developed for studying the components of the polymerelectrolyte fuel cell (PEFC). Humidifiers and other componentswere tested in order to develop reproducible and reliableexperimental techniques. A set-up for testing larger cells andstacks was developed. READ MORE

  5. 3. Optimization of Ohmic Contacts and Surface Passivation for ‘Buffer-Free’ GaN HEMT Technologies

    Author : Chen Ding Yuan; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; QuanFINE; passivation; GaN HEMT; pretreatment; ohmic contact;

    Abstract : Gallium nitride high electron mobility transistors (GaN HEMTs) draw attention from high frequency and high power industries due to unique properties including high electron mobility and saturation velocity combined with high breakdown voltage. This makes GaN HEMTs suitable for power devices with high switching speed and high frequency applications with high power density requirements. READ MORE

  6. 4. Low-friction and wear-resistant carbon nitride coatings for bearing components grown by magnetron sputtering

    Author : Konstantinos Bakoglidis; Grzegorz Greczynski; Lars Hultman; Susann Schmidt; Witold Gulbinski; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Carbon nitride; magnetron sputtering; physical vapor deposition; coatings; bearings; rolling contact fatigue; adhesion; friction; wear; transmission electron microscopy; scanning electron microscopy; x-ray photoelectron spectroscopy; coatings tribology; nanotribology;

    Abstract : The scope of this thesis is the investigation of magnetron sputtered carbon nitride coatings suitable for roller bearing components. The research field of tribology of bearings focuses on minimizing friction between components by improving the lubricants. READ MORE

  7. 5. Electrode degradation in proton exchange membrane fuel cells

    Author : Alejandro Oyarce; Göran Lindbergh; Carina Lagergren; Steven Holdcroft; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PEMFC; PEFC; Porous electrodes; Carbon corrosion; Carbon nanotubes; Carbon fibers; Polyhedral carbon nanofoams; Phosphonated hydrocarbon ionomer; Mass-transport losses; Electrode morphology; Electrode collapse; Start-up and shut-down; System strategies; Stainless steel; Bi-polar plates; In-situ contact resistance.;

    Abstract : The topic of this thesis is the degradation of fuel cell electrodes in proton exchange membrane fuel cells (PEMFCs). In particular, the degradation associated with localized fuel starvation, which is often encountered during start-ups and shut-downs (SUs/SDs) of PEMFCs. At SU/SD, O2 and H2 usually coexist in the anode compartment. READ MORE