Sökning: "Hydrogen Impurities"

Visar resultat 1 - 5 av 33 avhandlingar innehållade orden Hydrogen Impurities.

  1. 1. Hydrogen Impurities and Dislocations in Transition Metals

    Författare :Björn von Sydow; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Motion of impurities and dislocations is essential for many material properties of metals. In the present thesis we have made use of different atomistic simulation techniques to study the behavior of hydrogen and edge dislocations in transition metals. We have carried out molecular-dynamics (MD) simulations for hydrogen diffusion in niobium. LÄS MER

  3. 2. The Impact of Hydrocarbon and Carbon Oxide Impuritiesin the Hydrogen Feed of a PEM Fuel Cell

    Författare :Katrin Kortsdottir; Rakel Wreland Lindström; Göran Lindbergh; Tanja Kallio; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fuel Cell; Hydrogen Impurities; Carbon Monoxide; Carbon Dioxide; Ethene; Propene; Methane; Propane; Toluene; Electrochemically Active Surface Area; Cyclic Voltammetry; Mass Spectrometry; bränslecell; vätgasföroreningar; kolmonoxid; koldioxid; eten; propen; metan; propan; toluen; elektrokemisk aktiv yta; cyklisk voltammetri; masspektrometri; Chemical Engineering; Kemiteknik;

    Sammanfattning : The proton exchange membrane fuel cell generates electricity from hydrogen and oxygen (from air) through electrocatalytic reactions in an electrochemical cell. The Pt/C catalyst, commonly used in PEM fuel cells, is very sensitive to impurities that can interact with the active catalyst sites and limit fuel cell performance. LÄS MER

  4. 3. Gyrokinetic simulations of microturbulence and transport in tokamak plasmas

    Författare :Daniel Tegnered; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ITG; Joint European Torus; impurities; transport; fusion; TEM; tokamak; turbulence; plasma physics; gyrokinetics;

    Sammanfattning : Fusion power is one of few viable and sustainable means of energy production. The tokamak is arguable the most mature technology to magnetically confine fusion plasmas. In these devices, heat and particle transport is dominated by small-scale turbulent fluctuations. LÄS MER

  5. 4. Electrochemical Reactions in Polymer Electrolyte Fuel Cells

    Författare :Maria Wesselmark; Svein Sunde; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fuel cell; model electrodes; oxygen reduction; methanol oxidation; formic acid oxidation; hydrogen oxidation; CO oxidation; degradation; tungsten oxide; carbon support; Bränslecell; modellelektroder; syrgasreduktion; metanoloxidation; myrsyraoxidation; vätgasoxidation; CO oxidation; degradering; wolfram oxid; kolsupport; Chemical engineering; Kemiteknik;

    Sammanfattning : The polymer electrolyte fuel cell converts the chemical energy in a fuel, e.g. hydrogen or methanol, and oxygen into electrical energy. The high efficiency and the possibility to use fuel from renewable sources make them attractive as energy converters in future sustainable energy systems. LÄS MER

  7. 5. Atomic Spectroscopy on Fusion Relevant Ions and Studies of Light Impurities in the JET Tokamak

    Författare :Magnus Tunklev; Partikel- och kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Active and Passive Charge Exchange; Transport; Diffusion; Convection; Neutral Background Densities; Ion temperatures; Fusion; Isoelectronic sequences; Plasma; Atom- och molekylärfysik; Fysicumarkivet A:1999:Tunklev; Ritz formalism; Plume; Atomic and molecular physics;

    Sammanfattning : The spectrum and energy levels C IV and the 3l4l' system of the Mg-like ions in the iron group elements has been investigated. This has led to several hundred identified transitions, many of them previously unknown. LÄS MER