Sökning: "gas diffusion layers"

Visar resultat 1 - 5 av 34 avhandlingar innehållade orden gas diffusion layers.

1. 1. On Diffusion Transport Properties in Fuel Cell Gas Diffusion Layers Using the Lattice Boltzmann Method

   Författare :Mayken Espinoza Andaluz; Värmeöverföring; []
   Nyckelord :PEFC; lattice Boltzmann method; gas diffusion layers; porosity; Gas-phase tortuosity; permeability; inertial coefficient; diffusibility; pore-scale modeling;

   Sammanfattning : The polymer electrolyte fuel cell (PEFC) is considered as one of the most promising devices for providing efficient, clean and noiseless conversion of chemical energy to electrical energy. This device can provide electrical and thermal energy for transport, mobile and stationary applications ranging in a wide range of power requirements. LÄS MER

3. 2. Hydrogen in nano-sized metals : Diffusion and hysteresis effects

   Författare :Wen Huang; Björgvin Hjörvarsson; Max Wolff; Gavin Walker; Uppsala universitet; []
   Nyckelord :Hydrogen; diffusion; hysteresis; optical technique; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : Metal hydrides can be used as hydrogen storage materials for fuel cells and batteries, and as sensors for detecting hydrogen gas. The use of metal hydrides for hydrogen storage can be hindered by poor kinetics and low capacity. Moreover, poor sensitivity, long recovery and response time, limit the applications of metal hydrides as hydrogen sensors. LÄS MER

4. 3. Molecular overlayers on homogeneous and heterogeneous metal surfaces studied by core-level photoemission

   Författare :Maria Smedh; Fysiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; photoelectron spectroscopy; core-level photoemission; electron energy loss spectroscopy; single crystal surfaces; metal surfaces; heterogeneous surfaces; adsorption; adsorbed molecules; hydrocarbons; molecular vibrations; carbon monoxide; adsorption sites; adsorption energy; diffusion; dissociation; Physics; Fysik; Fysicumarkivet A:2001:Smedh;

   Sammanfattning : The main topic of this thesis is the investigation of small molecules adsorbed on metal surfaces by means of core-level photoemission spectroscopy. The thesis consists of three parts; The first group of papers concerns the effects of internal molecular vibrations on the core-level photoemission spectra. LÄS MER

5. 4. Analysis of Deformation of Gas Diffusion Layers and the Impact on Performance of PEM Fuel Cells

   Författare :Jiatang Wang; Värmeöverföring; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; PEM fuel cell; compression ratio; assembly pressure; porosity; deformed GDL; electric resistance; transport phenomena; model; performance; analysis; OpenFOAM;

   Sammanfattning : Proton exchange membrane (PEM) fuel cells have been promoted due to significant breakthroughs in various aspects and increasing public interests. The porous features of the gas diffusion layer (GDL) and the necessary assembly processes generate localized pressure forces on the channel/shoulder structure of the bi-polar plates (BPP). LÄS MER

7. 5. Drying of Multicomponent Liquid Films

   Författare :Fabio Luna; KTH; []
   Nyckelord :ternary mixture; falling film; diffusion equation; gas-phase control; liquid-phase control; selectivity; stability analysis; polymeric solution; evaporation; azeotrope; batch drying; continuous drying;

   Sammanfattning : The convective drying of thin layers of multicomponentliquid mixtures into an inert gas, and the influence ofdifferent process controlling mechanisms on drying selectivityis studied. Drying experiments under gas-phase-controlledconditions are performed by low intensity evaporation, fromfree liquid surfaces, of ternary mixtures without non-volatilesolutes. LÄS MER