Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"high pressure experiments"”.
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Development of New Methods to Control Redox Conditions in High-pressure Experiments and their Application to Study Ore Metal Solubilities in Sulfur-bearing Magmatic Fluids
… calculated amounts of H2 gas to the argon pressure medium to impose desired fO2 values in hydrous experiments. Using CoPd alloy redox sensors, the method was shown to be accurate within 0.3 log units for the P-T range of 960 – 2060 bar and 800 – 1100⁰C. The rate of progressive oxidation …
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The electronic, optical and excitonic effects of high hydrostatic pressure on semiconductors
This thesis describes the results from high pressure experiments on semiconductors, and some theoretical background for those experiments. The primary goal is to better understand the properties of these useful materials through studies of the effect of hydrostatic pressure.
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Iron-Nickel-Sulfur-Carbon System Under High Pressure, With Implications To Earth’S Mantle
… Physically, Fe-Ni-S-C phases have distinctly higher densities, surface tensions, and electrical conductivities, and lower melting points than mantle silicates. Understanding the geochemical and geophysical impacts caused by Fe-Ni-S-C phases requires accurate quantification of the basic …
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Pressure-Temperature Phase Diagram of LiAlH4
High pressure behavior of complex hydrides is investigated in this thesis. Raman spectroscopy was performed at different temperatures and pressures to determine structural changes in LiAlH4. In situ high-pressure/high-temperature Raman spectroscopy experiments were carried out using resistively …
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Study of Functional Complex Oxides at High Pressure-Temperature Conditions
… representative complex oxides studied under high pressures and temperatures. Synchrotron X-ray diffraction, Raman spectroscopy, neutron scattering, and first-principles calculations were used to probe the structural response of Li2CoO2F across multiple length scales. These studies reveal how …
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Dynamical perspective of stability in glasses
… treatments including X-ray irradiation and high-pressure compression. Vibrational dynamics are characterized through the vibrational density of states measured by Nuclear Resonant Analysis of Inelastic X-ray Scattering and Raman spectroscopy, while slow relaxation processes are probed via …
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Experimental Constraints on Melting Processes in the Earth and Small Rocky Bodies
… a multidisciplinary approach that integrates high-pressure experiments, geochemical analysis, and petrologic modeling. In Chapter 1, I examine the mantle source lithology of Hawaiian pre-shield tholeiitic volcanism through high-pressure equilibrium experiments and geochemical modeling. In …
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The partial molar volume of carbon dioxide in peridotite partial melt at high pressure
… was determined for a komatiite composition using high pressure sink/float experiments in a multi-anvil press. The density of the experimental melt at pressure was determined by observing sinking and floating of pure forsterite (Fo100) and 90% forsterite (Fo90) buoyancy markers. Values for VCO2 …
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Chemical Physics of Hydrazine Under Pressure
… best known for its long-standing use as a high-performance rocket fuel. Its rich hydrogen-bonding network and reactive N–N bond make it an ideal system for investigating how pressure alters molecular interactions, structure, and thermodynamic stability. High pressure provides a unique …
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Absarokites from the Western Mexican Volcanic Belt : constraints on mantle wedge conditions
… Mexico. Sample M.102 was chosen because it has high MgO contents, a high Mg# and F090 olivine phenocrysts, indicating it is primitive mantle melt. High-pressure experiments on a synthetic analogue of the absarokite composition with a H2O content of either -1 7 wt% or -5.1 wt% were cared out in a …
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Computational modeling of the densification of silica glass under shock loading
Under extremely high pressures (greater than 10 GPa), glass undergoes a severe permanent reduction in volume. The permanent densification of glass serves as a mechanism for the material to absorb large amounts of energy under pressures potentially achievable during ballistic loading. This ability …
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Using Lunar Apatite to Assess the Volatile Inventory of the Lunar Interior
… lunar conditions. This composition was used high temperature, high pressure experiments which constrained volatile partitioning between apatite and silicate melt. Combining experiments from this study, and those of the literature, an empirical model was developed to back-calculate melt …
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Structure-property relationships of earth and engineered materials
… of these particles combined with particle-target experiments (conducted for different permutations of particle impact speed, angle of incidence, and target material type) reveal that erosion of targets from impacts of test dust particles is driven by normal particle impact velocity and target …
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Experimental, geochemical and isotopic insights on melting and degassing behavior on Earth
… Science problems, parallels are drawn between experiments investigating melting and degassing at high pressure, geochemical and isotopic fingerprints of the Earth’s oldest rocks, and kinetic processes associated with aqueous supercritical fluids. The main lines of investigation rely on the …
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HIGH-PRESSURE BEHAVIOUR AND CRYSTAL-FLUID INTERACTION OF THE ABC-6 ZEOLITES: THE CASE OF ERIONITE, OFFRETITE AND BELLBERGITE
… those more than 50 found as natural species, highlighting the considerable crystallographic diversity and the scientific and industrial interest on zeolites. In the last decades, the scientific community showed a rising interest on the high-pressure behaviour (ranging from few kbar to GPa) of …
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(Na,K) Aluminosilicate Hollandites: Structures, Crystal Chemistry, and High-pressure Behaviour
… of the K-Na system at different temperatures and pressures, and to determine the physical-chemical properties and high-pressure behaviour of silicate hollandite-type structures containing K and Na in different concentrations. The (Na,K)AlSi3O8 hollandite solid solution has been synthesised using …
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Geobarometry, phase relations and elasticity of eclogite under conditions of Earth’s upper mantle
… clinopyroxene is sensitive to temperature and pressure, therefore eclogitic outcrops and xenoliths can reveal important information on the chemical and mineralogical processes occurring during such episodes. This is particularly the case for lithospheric eclogitic xenoliths from Archean …
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Phosphor(V)-nitride durch Hochdruck-Hochtemperatur-Synthese
1. Development and establishment of the high-pressure high-temperature synthesis as a broad approach to nitridophosphates. In this thesis for the first time a broad access to nitridophosphates was developed and therefore the basis for a systematic investigation of this class of compounds was …