Sökning: "oxygen impurities"

Visar resultat 1 - 5 av 41 avhandlingar innehållade orden oxygen impurities.

  1. 1. Critical potential and oxygen evolution of the chlorate anode

    Författare :Linda Nylén; Göran Lindbergh; Yohannes Kiros; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; chlorate; chloride oxidation; oxygen evolution; critical anode potential; chromate; DSA; mass transport; RDE; Chemical engineering; Kemiteknik;

    Sammanfattning : In the chlorate process, natural convection arises thanks to the hydrogen evolving cathode. This increases the mass transport of the different species in the chlorate electrolyte. There is a strong connection between mass transport and the kinetics of the electrode reactions. LÄS MER

  3. 2. Local structure and composition : in additively manufactured bulk metallic glasses and composites

    Författare :Inga Katharina Goetz; Jochen M. Schneider; Björgvin Hjörvarsson; Ulf Jansson; Maria Teresa Pérez Prado; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; additive manufacturing; bulk metallic glasses; nanoscale clustering; convective flow; laser nitriding; laser powder bed fusion; metallic glass - ceramic composites; oxygen impurities; mechanical properties; magnetic properties; viscosity; Fysik; Physics;

    Sammanfattning : Additive manufacturing enables the production of complex multi-material geometries and bulk metallic glass parts beyond their critical casting thickness. The local modification of structure, composition, and properties is explored in this thesis with the aim to design novel composite materials and functional gradients. LÄS MER

  4. 3. 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

  5. 4. Tailored process gases for laser powder bed fusion

    Författare :Camille Nicole Géraldine Pauzon; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Helium; Laser powder bed fusion; AM process productivity; Spatter particles; Residual oxygen; 316L stainless steel; Argon; Nitrogen; Additive manufacturing; Process atmosphere; Process stability; Residual stresses.; Ti-6Al-4V; Alloy 718;

    Sammanfattning : Metal laser powder bed fusion (L-PBF) allows for production of complex components using the energy from a laser to locally melt micron-sized powder following a layer-wise approach. Considerable scientific efforts are focused on addressing the influence of the process parameters on the melting stability and the control of material properties, while developing necessary monitoring and characterization tools. LÄS MER

  7. 5. Powder degradation during powder bed fusion processing

    Författare :Ahmad Raza; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser-based powder bed fusion; Alloy 718; Powder degradation; Oxidation; Electron beam powder bed fusion; Additive manufacturing; AlSi10Mg; Residual oxygen; Spatter particles; Sublimation.;

    Sammanfattning : Powder bed fusion (PBF) techniques, including laser-based powder bed fusion (LB-PBF) and electron beam powder bed fusion (EB-PBF), are two rapidly growing additive manufacturing (AM) processes due to their ability to produce complex geometries in near-net shapes. To attain reproducibility and repeatability in PBF processes, a consistent set of powder properties is vital. LÄS MER