Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item The rise of caldera forming eruptions: refining tools for understanding magma ascent(Montana State University - Bozeman, College of Letters & Science, 2022) Harris, Megan Ann; Chairperson, Graduate Committee: Madison Myers; This is a manuscript style paper that includes co-authored chapters.The rate at which magma moves from the magma chamber to the surface influences the amount of degassing and crystallization that occurs, which in turn controls the style and intensity of the ensuing eruption. Thus, our understanding of magma ascent rates is crucial to understanding and mitigating future volcanic hazards. The bulk of this dissertation revolves around using the diffusion of water through melt-filled pockets (embayments) in quartz crystals as an ascent speedometer, coupled with geochemical and textural analysis of co-erupted material. In Chapter Two, I apply and refine the water diffusion speedometer to establish timescales of ascent for the two eruptions that formed the modern-day Valles Caldera, with the aim of understanding whether these rates change during subsequent eruptions from the same caldera. In Chapter Three, I apply the diffusion speedometer to the opening behavior of the 1991 eruption of Mount. Pinatubo and compare the results to ascent rates obtained using independent petrologic methods (bubble number density and microlite number density). This chapter seeks to reconcile the several orders of magnitude offset in ascent rates produced by various geospeedometers. Finally, in Chapter Four, I explore the mechanisms by which embayments are formed in magmatic systems. I do this by conducting a survey of cathodoluminescence images of crystals taken from five volcanic systems to determine how the embayments interact with the internal zoning of the crystal. I then attempt to form embayments experimentally using a cold-seal pressure vessel under variable magmatic conditions. The culmination of this work emphasizes that embayments are robust and faithful recorders of a magma's journey from its source to the surface and may be a critical piece of evidence for unraveling the magmatic history leading to eruption. This dissertation includes both previously published and unpublished co-authored work.Item Rare earth doped crystals for classical and quantum information(Montana State University - Bozeman, College of Letters & Science, 2021) Woodburn, Philip Joseph 'Tino'; Chairperson, Graduate Committee: Rufus L. Cone; This is a manuscript style paper that includes co-authored chapters.High-quality rare-earth-ion (REI) doped materials are a prerequisite for many applications such as quantum memories, ultra-high-resolution photonic signal processing, and quantum-limited sensing. Realization of practical solid-state photonic technologies critically depends on finding materials that offer necessary combinations of optical and spin-state coherence, spectral multiplexing capacity, transition wavelengths, and many other key properties. To realize these advances, we continue to improve the fundamental understanding and control of physical processes that govern ion-ion, ion-spin, and ion-lattice interactions. Furthermore, exploring the role of material chemistry and fabrication in determining the observed properties is crucial. With these motivations, we study a range of rare-earth-doped optical materials using powders and single crystals to understand and optimize the properties relevant to quantum memory, quantum transduction, photonic signal processing, and optical cooling applications. In addition to producing, measuring, and analysing spectroscopic and coherence properties of promising material systems, we highlight the engineering of lattice defects to manipulate both static and dynamic disorder. This work spans nine different REI doped materials: four single crystals, Tm 3+:Y 3Ga 5O 12, Yb 3+:YVO 4, Er 3+:Y 3Al 5O 12, and Er 3+:Y 2SiO 5, and five crystalline powders, Er 3+:LiNbO 3, Tm 3+:Y 3Al 5O 12, Tb 3+:Y 3Al 5O 12, Yb 3+:YAG, and Eu 3+:CaCO 3. These choices are based on material properties unique to each system, need for investigation, or potential for systematic comparison of fabrication methods and stoichiometry. Spectral hole burning (SHB), optical and spin coherence measurement techniques are sensitive quantitative characterization tools, complementing traditional optical, chemical, and structural analysis. We find that coherence and spin lifetimes are especially sensitive to low levels of strain and defects in the crystal, undetected by other methods. Properties of REI doped materials are found to vary by orders of magnitude depending on the source, synthesis, and implementation of the materials. Even mild mechanical processing producing large variations in spin lifetimes and SHB properties. These variations are attributed to low levels of glass-like dynamics in the crystalline lattice introduced by inhomogeneous strain and chemical defects, which can be reduced or eliminated by annealing or improved fabrication. Overall, these studies reveal that SHB or coherence measurements are needed to identify material dynamics and guide the fabrication process to reach the true fundamental capabilities of REI materials.Item Crystal pressure of pharmaceuticals in nanoscale pores(Montana State University - Bozeman, College of Engineering, 2017) Berglund, Emily Anne; Chairperson, Graduate Committee: James WilkingMany pharmaceutical compounds are poorly soluble in water. This is problematic because most pharmaceuticals are delivered orally and must dissolve in the gastrointestinal fluid to be absorbed by the body. Drug dissolution rate is proportional to surface area, so a common formulation strategy is to structure drugs as small as possible to maximize surface area. A simple approach to create very small particles is to structure the compounds within the nanoscale pore space of a colloidal packing. The resulting composite undergoes rapid disintegration in water and the exposed drug exhibits dramatically improved dissolution rates. We hypothesize that composite breakup is driven by the growth of nanoscale crystals, which exert a pressure on the walls of the confining pores. To test this hypothesis, we systematically vary the amount of water permitted into the composite and use calorimetry to monitor the evolution of the crystal size distribution as a function of water content. To exert sufficient pressure to overcome the tensile yield stress of the composite, the crystals must be fed by a supersaturated phase. Our results suggest that differences in crystal curvature due to crystal confinement and crystal size polydispersity generate the necessary supersaturation. These results are relevant not just for drug formulations, but for understanding physical processes such as salt damage to buildings and road damage due to frost heave.Item A neutron diffraction and NMR study of ferroelectric and antiferroelectric ordering in CsH2PO4 at high pressure(Montana State University - Bozeman, College of Letters & Science, 1988) Schuele, Paul JohnItem Crystal and molecular structure of phosphetane oxides(Montana State University - Bozeman, College of Letters & Science, 1974) Campbell, James AllenItem Structural studies of organo-phosphorus (V) esters and thioesters(Montana State University - Bozeman, College of Letters & Science, 1973) Warrant, Ronald Wade