Sökning: "gas permeability"

Visar resultat 1 - 5 av 56 avhandlingar innehållade orden gas permeability.

  1. 1. Factors Related to the Formation of Gas Porosity in Grey Cast Iron: Investigation of Core Gas Evolution and Gas Concentrations in Molten Iron

    Författare :Jessica Orlenius; [2008]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; core binders; Gas porosity; hydrogen; grey iron; gas absorption; nitrogen; oxygen; gas evolution rate; green sand; mould filling; gas volume; gas solubility;

    Sammanfattning : Since gas porosity is a major casting problem, it is of greatest importance to increase the knowledge about the foundry process in order to minimise the presence of gas porosity and thereby improving the casting quality. Gas porosity is generally considered to originate from gases precipitated during solidification of iron and from entrained gas picked up by the metal during the mould filling. LÄS MER

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

    Detta är en avhandling från Department of Energy Sciences, Lund University

    Författare :Mayken Espinoza Andaluz; [2017]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 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. 3. Alternative methods for analysing moisture transport in buildings Utilisation of tracer gas and natural stable isotopes

    Detta är en avhandling från Stockholm : KTH

    Författare :Kjartan Gudmundsson; KTH.; [2003]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tracer gas; water vapour permeability; diffusion; surface diffusion; isotopic analysis; deuterium; oxygen-18; fractionation; vapour barrier; transient numerical modelling of diffusion; TECHNOLOGY Civil engineering and architecture Building engineering; TEKNIKVETENSKAP Samhällsbyggnadsteknik och arkitektur Byggnadsteknik;

    Sammanfattning : New methods, based on tracer gas measurements and isotopicanalysis can be used to evaluate the moisture properties ofbuilding materials and provide the means for forensic analysisof the origins and history of excessive water in buildings, theimmediate practical consequences of which will be the abilityto improve the moisture performance of constructions.It is shown, in theory and through measurements how thewater vapour permeability of porous building materials can witha good degree of accuracy be estimated with tracer gasmeasurements that provide an efficient alternative to the cupmethod. LÄS MER

  4. 4. Transport in Oxides Studied by Gas Phase Analysis

    Detta är en avhandling från Stockholm : KTH

    Författare :Qian Dong; KTH.; [2007]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Gas Phase Analysis; metal; oxide; platinum; vitreous silica; yttria stabilized zirconia; diatomic gas; oxidation; dissociation; permeation; uptake release.; TECHNOLOGY Chemical engineering; TEKNIKVETENSKAP Kemiteknik;

    Sammanfattning : The transport in oxides is studied by the use of gas phase analysis (GPA). An experimental method to identify transported species of gases and their contribution to the overall transport of gases in oxides and an experimental method to evaluate the parameters diffusivity, concentration, permeability of gases in oxides and effective pore size in oxides are developed, respectively. LÄS MER

  5. 5. Investigations of proton conducting polymers and gas diffusion electrodes in the polymer electrolyte fuel cell

    Detta är en avhandling från Stockholm : KTH

    Författare :Peter Gode; KTH.; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical chemistry; polymer electrolyte fuel cell; proton conducting membrane; porous electrode; gas permeability; degradation; water transport; Teoretisk kemi; NATURAL SCIENCES Chemistry Theoretical chemistry; NATURVETENSKAP Kemi Teoretisk kemi;

    Sammanfattning : Polymer electrolyte fuel cells (PEFC) convert the chemically bound energy in a fuel, e.g. hydrogen, directly into electricity by an electrochemical process. Examples of future applications are energy conversion such as combined heat and power generation (CHP), zero emission vehicles (ZEV) and consumer electronics. LÄS MER