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Full-Text Articles in Physical Sciences and Mathematics
Microstructural Characterization Of Kinked Germanate Olivine Grains, Alex Gregory Drue
Microstructural Characterization Of Kinked Germanate Olivine Grains, Alex Gregory Drue
UNLV Theses, Dissertations, Professional Papers, and Capstones
Olivine is the most common and the weakest mineral in the upper mantle. Thus the strength of olivine controls the rheology of the earth's upper mantle. The rheology of olivine in the upper mantle has important implications for mantle flow, mountain building, and rates of isostatic adjustment. Recent experimental measurements of the flow strength of deformed olivine polycrystals have assumed a homogeneous state of stress. X-ray synchrotron diffraction experiments have implied that this assumption is not always valid. Elastic Plastic Self Consistent (EPSC) modeling offers an approach to estimating the flow strength of olivine that does not assume a homogeneous …
Raman Spectroscopic Study Of Solid Solution Spinel Oxides, Brian D. Hosterman
Raman Spectroscopic Study Of Solid Solution Spinel Oxides, Brian D. Hosterman
UNLV Theses, Dissertations, Professional Papers, and Capstones
Solid solution spinel oxides of composition MgxNi1−xCr2O4, NiFexCr2−xO4, and FexCr3−xO4 were synthesized and characterized using x-ray diffraction and Raman spectroscopy. Frequencies of the Raman-active modes are tracked as the metal cations within the spinel lattice are exchanged. This gives information about the dependence of the lattice vibrations on the tetrahedral and octahedral cations. The highest-frequency Raman-active mode, A1g, is unaffected by substitution of the divalent tetrahedral cation, whereas the lower frequency vibrations are more strongly affected by substitution of the tetrahedral cation. The change in wavenumber of many phonons is nonlinear upon cation exchange. All detected modes of MgxNi1−xCr2O4 and …