Sökning: "hydrogen gas"

Visar resultat 1 - 5 av 432 avhandlingar innehållade orden hydrogen gas.

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; Chalmers tekniska högskola; []
   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

3. 2. Full gas mot en (o)hållbar framtid : Förväntningar på bränsleceller och vätgas 1978 - 2005 i relation till svensk energi- och miljöpolitik

   Författare :Martin Hultman; Jonas Anshelm; Christer Nordlund; Linköpings universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Environmental history; discourse; STS; history of technology; sociology of expectations; hydrogen; fuel cell; utopia; material~semiotics; cultural studies; Miljöhistoria; mijlöteknik; teknik- och vetenskapsstudier; energipolitik; diskurs; utopier; förväntanssocilogi; materiell- semiotik; kulturstudier; teknikhistoria; vätgas; bränsleceller; INTERDISCIPLINARY RESEARCH AREAS; TVÄRVETENSKAPLIGA FORSKNINGSOMRÅDEN;

   Sammanfattning : I föreliggande avhandling undersöker Hultman hur bränsleceller och vätgas underolika tidpunkter beskrivits som delar i ett framtida energisystem 1978 – 2005. Detempiriska materialet som analyseras är statliga utredningar, böcker, rapporter,tidningsartiklar och riksdagstryck. LÄS MER

4. 3. Cyanobacterial Hydrogen Metabolism - Uptake Hydrogenase and Hydrogen Production by Nitrogenase in Filamentous Cyanobacteria

   Författare :Pia Lindberg; Peter Lindblad; Kornél Kovács; Uppsala universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Microbiology; cyanobacteria; biohydrogen; Nostoc; hydrogen production; hydrogen evolution; hydrogen metabolism; nitrogenase; hydrogenase; hydrogen; uptake hydrogenase; hupSL; hydrogen uptake mutant; uptake hydrogenase mutant; photobioreactor; hydrogenase accessory genes; hyp; transcription; RT-PCR; NtcA; mass spectrometry; heterocyst; Mikrobiologi; Microbiology; immunology; infectious diseases; Mikrobiologi; immunologi; infektionssjukdomar;

   Sammanfattning : Molecular hydrogen is a potential energy carrier for the future. Nitrogen-fixing cyanobacteria are a group of photosynthetic microorganisms with the inherent ability to produce molecular hydrogen via the enzyme complex nitrogenase. This hydrogen is not released, however, but is recaptured by the bacteria using an uptake hydrogenase. LÄS MER

5. 4. Electrochemical reduction of protons and organic molecules in hydrogen technologies : Liquid Organic Hydrogen carrier and Hydrogen Evolution

   Författare :Hamid Ghorbani Shiraz; Magnus Berggren; Xavier Crispin; Ola Wendt; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrogen Storage; LOHC; Hydrogen Evolution; Electrocatalyst;

   Sammanfattning : In accordance with preventable actions to mitigate the effect of climate change in the modern societal applications, renewable energy is an unavoidable and decisive factor in the energy industry. The energy sources that offer non-depleted and environment-friendly pathways for the energy sector are in focus. LÄS MER

7. 5. Synchrotron radiation studies of gas phase molecules : from hydrogen to DNA sugars

   Författare :Gemma Vall-llosera; Elisabeth Rachlew; Stacey Sorensen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; KTH thesis; synchrotron radiation; gas phase; bio molecules; Atomic and molecular physics; Atom- och molekylfysik;

   Sammanfattning : This thesis summarises experimental results on the molecular spectroscopy of gas phase molecules excited by synchrotron radiation in the VUV and soft X-ray regions. We have used three different detection techniques, photon induced fluorescence spectroscopy, photoionisation mass spectroscopy and near edge X-ray absorption fine structure spectroscopy to study molecular deuterium, hydrogen sulphide, ammonia, methanol, pyridine, pyridazine, pyrimidine, pyrazine, s-triazine, and 2-deoxy-D-ribose, the last one also known as the DNA sugar. LÄS MER