Search for dissertations about: "Rietveld"

Showing result 1 - 5 of 31 swedish dissertations containing the word Rietveld.

  1. 1. Crystal chemistry of Fe-Ti oxides in mafic rocks and metabasites: A study aimed at refinement of geological tools and interpretations

    University dissertation from Department of Mineralogy and Petrology, Lund University

    Author : Benyam Estifanos; Lunds universitet.; Lund University.; [1997]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fe-Ti oxide; hercynite; siderite; stilpnomelane; olivine corona; Swedish Caledonides; hysteresis; PIXE; synchrotron XRD; Rietveld; microprobe; red corundum; palaeomagnetism; eclogite; plagioclase clouding; dolerite; pyroxene gneiss; Geology; physical geography; Geologi; fysisk geografi;

    Abstract : This thesis consists of four subprojects: (A) ‘Clouding of plagioclase by Fe-Ti oxides’, (B) ‘Fe-Ti oxides during high-pressure metamorphism of mafic rocks’, (C) ‘Magnetic study of Fe-Ti oxides in mafic rocks and metabasites’, and (D) ‘Topotactic phase transitions in oxide minerals’. A) In southern Sweden dolerite dikes and gabbros with clouded plagioclase are common. READ MORE

  2. 2. Proton Conducting Ceramics; Synthesis, Characterization and Sample Cell Environments

    University dissertation from Department of Mineralogy and Petrology, Lund University

    Author : FRANCIS GACHAO KINYANJUI; [2012]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; perovskites; neutron diffraction; Rietveld refinements; BaSnO3; in-situ cell; deuteron position; proton conduction; BaZrO3;

    Abstract : Acceptor doped Perovskite ceramics have been shown to exhibit high levels of protonic conduction in humid atmospheres. However significant grain boundary resistance and long sintering times required to achieve sufficient grain size growth has hindered their widespread application as electrolyzers, fuel cells and gas separation membranes. READ MORE

  3. 3. Acceptor-Doped BaZrO3 Perovskite: Synthesis, Structure and Proton Conductivity

    University dissertation from Department of Mineralogy and Petrology, Lund University

    Author : Istaq Ahmed; [2008]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Impedance spectroscopy; Perovskite; Neutron diffraction; Rietveld refinement; BaZrO3.; Proton conductor;

    Abstract : Acceptor-doped perovskite oxides exhibit significant proton conductivity in hydrogen containing atmospheres. Therefore, they have potential for use as separator materials for various electrochemical devices including gas sensors, electrolysers and fuel cells. READ MORE

  4. 4. Influence of solid solutions on the properties of some apatite-type calcium salts relevant to the production of phosphate and silicate cements

    University dissertation from Simon Jegou Saint-Jean (or Pr. Staffan Hansen), Materials Chemistry, Lund University

    Author : Simon Jegou Saint-Jean; Lunds universitet.; Lund University.; [2004]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Materiallära; materialteknik; Chemical technology and engineering; Kemiteknik och kemisk teknologi; Material technology; isothermal calorimetry.; Rietveld method; X-ray diffraction; silicon; strontium; Portland cement; calcium phosphate cement; chlorellestadite; Solid solutions; apatite;

    Abstract : The effects of non-stoichiometry and isomorphic substitutions on the properties of some apatite-type compounds were investigated. These investigations were performed both in the fields of Portland cement chemistry and apatitic calcium phosphate-based biocements. READ MORE

  5. 5. The rational design of lithium insertion materials for battery applications

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Helena Berg; Uppsala universitet.; [1999]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemistry; cathode materials; lithium manganese oxide; in situ neutron diffraction; Rietveld refinement; band-structure calculations; Kemi; NATURAL SCIENCES Chemistry; NATURVETENSKAP Kemi; Inorganic Chemistry; oorganisk kemi;

    Abstract : The transition-metal oxide spine1 LiMn2O4 is a promising cathode material for high-capacity lithium-ion batteries. Structure-property relationships pertaining to the electrochemical cycling behaviour of LiMn2O4 have been studied. READ MORE