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• 41. [Article] Optomechanical Light Storage and Related Transient Optomechanical Phenomena

  An optomechanical system consists of an optical cavity coupled to a mechanical oscillator. The system used for this work was a silica microsphere. In a silica microsphere, the optical cavity is formed ...

  Citation × Citation Citation Abstract Copy Title: Optomechanical Light Storage and Related Transient Optomechanical Phenomena Author: Fiore, Victor Year: 2015 An optomechanical system consists of an optical cavity coupled to a mechanical oscillator. The system used for this work was a silica microsphere. In a silica microsphere, the optical cavity is formed by light that is confined by total internal reflection while circulating around the equator of the sphere. The mechanical oscillator is the mechanical breathing motion of the sphere itself. The optical cavity and mechanical oscillator are coupled by radiation pressure and by the mechanical oscillator physically changing the length of the optical cavity. The optomechanical analog to electromagnetically induced transparency (EIT), known as optomechanically induced transparency (OMIT), has previously been studied in its steady state. One topic of this dissertation is an experimental study of OMIT in the time domain. The results of these experimental demonstrations continue comparisons between EIT and OMIT, while also building a foundation for optomechanical light storage. In OMIT, an off-resonance control laser controls the interaction between on-resonance light and the mechanical oscillator. Optomechanical light storage makes use of this arrangement to store an optical signal as a mechanical excitation, which is then retrieved at a later time as an optical signal. This is done by using two temporally separated off-resonance control laser pulses. This technique is extremely flexible in frequency and displays a storage lifetime on the order of microseconds. Use of optomechanical systems for quantum mechanical applications is hindered by the thermal background noise of the mechanical oscillator. Addressing this issue by first cooling the mechanical oscillator is costly and fraught with difficulties. The final topic presented in this dissertation deals with this issue through the use of an optomechanical dark mode. Two optical modes can interact with the same mechanical mode. The dark mode is a state that couples the two optical modes but is decoupled from the mechanical oscillator. While our specific optomechanical system is limited by its somewhat modest optomechanical cooperativity, this conversion process can, in principle, preserve the quantum state of the signal, even at room temperature, opening the possibility for this technique to be applied in quantum information processing. Title: Optomechanical Light Storage and Related Transient Optomechanical Phenomena Author: Fiore, Victor Year: 2015 An optomechanical system consists of an optical cavity coupled to a mechanical oscillator. The system used for this work was a silica microsphere. In a silica microsphere, the optical cavity is formed by light that is confined by total internal reflection while circulating around the equator of the sphere. The mechanical oscillator is the mechanical breathing motion of the sphere itself. The optical cavity and mechanical oscillator are coupled by radiation pressure and by the mechanical oscillator physically changing the length of the optical cavity. The optomechanical analog to electromagnetically induced transparency (EIT), known as optomechanically induced transparency (OMIT), has previously been studied in its steady state. One topic of this dissertation is an experimental study of OMIT in the time domain. The results of these experimental demonstrations continue comparisons between EIT and OMIT, while also building a foundation for optomechanical light storage. In OMIT, an off-resonance control laser controls the interaction between on-resonance light and the mechanical oscillator. Optomechanical light storage makes use of this arrangement to store an optical signal as a mechanical excitation, which is then retrieved at a later time as an optical signal. This is done by using two temporally separated off-resonance control laser pulses. This technique is extremely flexible in frequency and displays a storage lifetime on the order of microseconds. Use of optomechanical systems for quantum mechanical applications is hindered by the thermal background noise of the mechanical oscillator. Addressing this issue by first cooling the mechanical oscillator is costly and fraught with difficulties. The final topic presented in this dissertation deals with this issue through the use of an optomechanical dark mode. Two optical modes can interact with the same mechanical mode. The dark mode is a state that couples the two optical modes but is decoupled from the mechanical oscillator. While our specific optomechanical system is limited by its somewhat modest optomechanical cooperativity, this conversion process can, in principle, preserve the quantum state of the signal, even at room temperature, opening the possibility for this technique to be applied in quantum information processing. Close

• 42. [Article] Oxygen and hydrogen investigation of volcanic rocks: Petrogenesis to paleoclimate

  Knowledge of the isotopic evolution of volcanic eruptions is essential to volcanologists, geochemists, and paleoclimatologists. I isotopically evaluate the evolution of magmas from their initial formation, ...

  Citation × Citation Citation Abstract Copy Title: Oxygen and hydrogen investigation of volcanic rocks: Petrogenesis to paleoclimate Author: Seligman, Angela Year: 2016 Knowledge of the isotopic evolution of volcanic eruptions is essential to volcanologists, geochemists, and paleoclimatologists. I isotopically evaluate the evolution of magmas from their initial formation, to eruption, and then to their alteration during the diffusion of environmental waters into volcanic glass. I focus first on the formation and evolution of large, caldera-forming eruptions from both Gorely volcano in Kamchatka, Russia and 30–40 Ma caldera forming eruptions through Oregon in the United States of America. I utilize oxygen (δ18O), hafnium (εHf), strontium (87Sr/86Sr), and neodymium (143Nd/144Nd) isotopes to document the creation of caldera-forming eruptions at these eruptive centers through the melting of surrounding crust. I also use U-Pb and 40Ar/39Ar to document the timescales of the formation of these large-volume silicic eruptions. Following eruption, the volcanic glass in tephra and ash can slowly take in environmental water. It is thought that the hydrogen isotopic ratio (δD) of these waters can be used to determine paleoenvironments from the time that the volcanic glass was deposited. The latter portion of my dissertation focuses on the use of hydrogen isotopes of environmentally hydrated volcanic glass to determine paleoenvironments, and the calibration of the TCEA to analyze oxygen isotopes of hydrated volcanic glass. I first focus on the rate of diffusion of water at ambient temperature to better understand the time frame necessary to hydrate volcanic glass for use as a paleoenvironmental indicator. I also document the hydrogen isotopic ratios that result from the diffusion of water into volcanic glass, which is documented as a decrease in δD with an increase in secondary hydration in all regions worldwide except equatorial. Finally, I focus on the earliest stages of diffusion of water into volcanic glass by analyzing tephra deposits that were collected within days of the 1980 eruptions of Mount St. Helens as well as tephra deposits recently collected in 2015 to identify changes in water concentration and hydrogen isotopic ratios over an ~35 year period. Title: Oxygen and hydrogen investigation of volcanic rocks: Petrogenesis to paleoclimate Author: Seligman, Angela Year: 2016 Knowledge of the isotopic evolution of volcanic eruptions is essential to volcanologists, geochemists, and paleoclimatologists. I isotopically evaluate the evolution of magmas from their initial formation, to eruption, and then to their alteration during the diffusion of environmental waters into volcanic glass. I focus first on the formation and evolution of large, caldera-forming eruptions from both Gorely volcano in Kamchatka, Russia and 30–40 Ma caldera forming eruptions through Oregon in the United States of America. I utilize oxygen (δ18O), hafnium (εHf), strontium (87Sr/86Sr), and neodymium (143Nd/144Nd) isotopes to document the creation of caldera-forming eruptions at these eruptive centers through the melting of surrounding crust. I also use U-Pb and 40Ar/39Ar to document the timescales of the formation of these large-volume silicic eruptions. Following eruption, the volcanic glass in tephra and ash can slowly take in environmental water. It is thought that the hydrogen isotopic ratio (δD) of these waters can be used to determine paleoenvironments from the time that the volcanic glass was deposited. The latter portion of my dissertation focuses on the use of hydrogen isotopes of environmentally hydrated volcanic glass to determine paleoenvironments, and the calibration of the TCEA to analyze oxygen isotopes of hydrated volcanic glass. I first focus on the rate of diffusion of water at ambient temperature to better understand the time frame necessary to hydrate volcanic glass for use as a paleoenvironmental indicator. I also document the hydrogen isotopic ratios that result from the diffusion of water into volcanic glass, which is documented as a decrease in δD with an increase in secondary hydration in all regions worldwide except equatorial. Finally, I focus on the earliest stages of diffusion of water into volcanic glass by analyzing tephra deposits that were collected within days of the 1980 eruptions of Mount St. Helens as well as tephra deposits recently collected in 2015 to identify changes in water concentration and hydrogen isotopic ratios over an ~35 year period. Close

• 43. [Article] Vulnerability to Climate Change: Assessing Trees on the University of Oregon Campus

  85 pages. Examining committee chair: Dr. Chris Enright

  Citation × Citation Citation Abstract Copy Title: Vulnerability to Climate Change: Assessing Trees on the University of Oregon Campus Author: Jorgensen, Matthew R. Year: 2016 85 pages. Examining committee chair: Dr. Chris Enright Title: Vulnerability to Climate Change: Assessing Trees on the University of Oregon Campus Author: Jorgensen, Matthew R. Year: 2016 85 pages. Examining committee chair: Dr. Chris Enright Close

• 44. [Article] Mantle flow and melting beneath young oceanic lithosphere: Seismic studies of the Galápagos Archipelago and the Juan de Fuca Plate

  In this dissertation, I use seismic imaging techniques to constrain the physical state of the upper mantle beneath regions of young oceanic lithosphere. Mantle convection is investigated beneath the Galápagos ...

  Citation × Citation Citation Abstract Copy Title: Mantle flow and melting beneath young oceanic lithosphere: Seismic studies of the Galápagos Archipelago and the Juan de Fuca Plate Author: Byrnes, Joseph Year: 2017 In this dissertation, I use seismic imaging techniques to constrain the physical state of the upper mantle beneath regions of young oceanic lithosphere. Mantle convection is investigated beneath the Galápagos Archipelago and then beneath the Juan de Fuca (JdF) plate, with a focus on the JdF and Gorda Ridges before turning to the off-axis asthenosphere. In the Galápagos Archipelago, S-to-p receiver functions reveal a discontinuity in seismic velocity that is attributed to the dehydration of the upper mantle. The depth at which dehydration occurs is shown to be consistent with prior constraints on mantle temperature. A comparison between results from receiver functions, seismic tomography and petrology shows that mantle upwelling and melt generation occur shallower than the depth of the discontinuity, despite the expectation of high viscosities in the dehydrated layer. Beneath the JdF and Gorda Ridge, low Vs anomalies are too large to be explained by the cooling of the lithosphere and are attributed to partial melt. The asymmetry, large Vs gradients, and sinuosity of the anomalies beneath the JdF Ridge are consistent with models of buoyancy-driven upwelling. However, deformation zone processes appear to dominate mantle flow over seafloor spreading beneath the Explorer and Gorda diffuse plate boundaries. Finally, S-to-p receiver functions reveal a seismic discontinuity beneath the JdF plate that can only be attributed to seismic anisotropy. Synthesis of the receiver function results with prior SKS splitting results requires heterogeneous anisotropy between the crust and the discontinuity. Models of anisotropy feature increasing anisotropy before the decrease at the discontinuity, but well below the base of the lithosphere, and a clockwise rotation of the fast direction with increasing depth. In these results and even in the SKS splitting results, additional driving mechanisms for mantle flow such as density or pressure anomalies are required. Title: Mantle flow and melting beneath young oceanic lithosphere: Seismic studies of the Galápagos Archipelago and the Juan de Fuca Plate Author: Byrnes, Joseph Year: 2017 In this dissertation, I use seismic imaging techniques to constrain the physical state of the upper mantle beneath regions of young oceanic lithosphere. Mantle convection is investigated beneath the Galápagos Archipelago and then beneath the Juan de Fuca (JdF) plate, with a focus on the JdF and Gorda Ridges before turning to the off-axis asthenosphere. In the Galápagos Archipelago, S-to-p receiver functions reveal a discontinuity in seismic velocity that is attributed to the dehydration of the upper mantle. The depth at which dehydration occurs is shown to be consistent with prior constraints on mantle temperature. A comparison between results from receiver functions, seismic tomography and petrology shows that mantle upwelling and melt generation occur shallower than the depth of the discontinuity, despite the expectation of high viscosities in the dehydrated layer. Beneath the JdF and Gorda Ridge, low Vs anomalies are too large to be explained by the cooling of the lithosphere and are attributed to partial melt. The asymmetry, large Vs gradients, and sinuosity of the anomalies beneath the JdF Ridge are consistent with models of buoyancy-driven upwelling. However, deformation zone processes appear to dominate mantle flow over seafloor spreading beneath the Explorer and Gorda diffuse plate boundaries. Finally, S-to-p receiver functions reveal a seismic discontinuity beneath the JdF plate that can only be attributed to seismic anisotropy. Synthesis of the receiver function results with prior SKS splitting results requires heterogeneous anisotropy between the crust and the discontinuity. Models of anisotropy feature increasing anisotropy before the decrease at the discontinuity, but well below the base of the lithosphere, and a clockwise rotation of the fast direction with increasing depth. In these results and even in the SKS splitting results, additional driving mechanisms for mantle flow such as density or pressure anomalies are required. Close

• 45. [Article] Noise Modeling Using Internet of Things

  101 pages. A thesis presented to the Department of Computer & Information Science and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor ...

  Citation × Citation Citation Abstract Copy Title: Noise Modeling Using Internet of Things Author: Deodhar, Anupama Vijay Year: 2017 101 pages. A thesis presented to the Department of Computer & Information Science and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017 Title: Noise Modeling Using Internet of Things Author: Deodhar, Anupama Vijay Year: 2017 101 pages. A thesis presented to the Department of Computer & Information Science and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017 Close

• 46. [Article] Novel Method for Additive Manufacture of Rubber with Exploration in Support Structure and Material Performance

  153 pages. A thesis presented to the Department of Product Design and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, ...

  Citation × Citation Citation Abstract Copy Title: Novel Method for Additive Manufacture of Rubber with Exploration in Support Structure and Material Performance Author: Hashiguchi, Sarah Elizabeth Year: 2017 153 pages. A thesis presented to the Department of Product Design and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017 Title: Novel Method for Additive Manufacture of Rubber with Exploration in Support Structure and Material Performance Author: Hashiguchi, Sarah Elizabeth Year: 2017 153 pages. A thesis presented to the Department of Product Design and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017 Close

• 47. [Article] Wavelet Analysis of Northeastern United States Climate Data

  59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2...

  Citation × Citation Citation Abstract Copy Title: Wavelet Analysis of Northeastern United States Climate Data Author: Womack, Michael Thomas Year: 2017 59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2017 Title: Wavelet Analysis of Northeastern United States Climate Data Author: Womack, Michael Thomas Year: 2017 59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2017 Close

• 48. [Article] Oocyte Meiotic Spindle Assembly in <italic>Caenorhabditis elegans</italic>

  As in many organisms, Caenorhabditis elegans oocytes assemble bipolar meiotic spindles in the absence of centrosomes. While the assembly of the mitotic spindle in C. elegans has been studied in some detail, ...

  Citation × Citation Citation Abstract Copy Title: Oocyte Meiotic Spindle Assembly in <italic>Caenorhabditis elegans</italic> Author: Connolly, Amy Year: 2014 As in many organisms, Caenorhabditis elegans oocytes assemble bipolar meiotic spindles in the absence of centrosomes. While the assembly of the mitotic spindle in C. elegans has been studied in some detail, how the poles assemble in the absence of centrosomes remains poorly understood. In an ongoing screen for temperature-sensitive (TS), embryonic-lethal mutants, we have identified TS mutations in multiple genes required for oocyte meiotic spindle pole assembly. We have so far identified mutations in four genes: or1178ts in mei-1, which encodes the catalytic domain of the microtubule severing complex katanin; or447ts in klp-18, which encodes a kinesin 12 family member; or645ts in aspm-1, which encodes a microtubule scaffolding protein; and or1092ts and or1292ts in klp-7, which encode a kinesin 13/MCAK family member. By using live cell imaging of oocytes from transgenic strains expressing GFP and mCherry fusion to proteins associated with the spindle, we have found and confirmed other findings that klp-18 promotes spindle bipolarity and that MEI-1 promotes pole assembly both by severing microtubules and by recruiting ASPM-1. More recently, we have found that klp-7 is required for maintaining bipolarity in the meiotic spindle by preventing the number of poles that can form. In klp-7(-) mutants, we observed in addition to extraneous poles an excess accumulation of microtubules during Meiosis I. Futhermore, reducing klp-7 function can restore bipolarity in a klp-18(-) monopolar spindle mutant background. We also observed that disruption of the kinetochore factor KNL-1 in klp-7(-) mutants exacerbates the extra spindle pole phenotype. We suggest that in oocyte meiosis, klp-7 is required to limit microtubule accumulation and pole assembly and that it may carry out these functions in a kinetochore-dependent manner. This dissertation includes previously published co-authored material. Title: Oocyte Meiotic Spindle Assembly in <italic>Caenorhabditis elegans</italic> Author: Connolly, Amy Year: 2014 As in many organisms, Caenorhabditis elegans oocytes assemble bipolar meiotic spindles in the absence of centrosomes. While the assembly of the mitotic spindle in C. elegans has been studied in some detail, how the poles assemble in the absence of centrosomes remains poorly understood. In an ongoing screen for temperature-sensitive (TS), embryonic-lethal mutants, we have identified TS mutations in multiple genes required for oocyte meiotic spindle pole assembly. We have so far identified mutations in four genes: or1178ts in mei-1, which encodes the catalytic domain of the microtubule severing complex katanin; or447ts in klp-18, which encodes a kinesin 12 family member; or645ts in aspm-1, which encodes a microtubule scaffolding protein; and or1092ts and or1292ts in klp-7, which encode a kinesin 13/MCAK family member. By using live cell imaging of oocytes from transgenic strains expressing GFP and mCherry fusion to proteins associated with the spindle, we have found and confirmed other findings that klp-18 promotes spindle bipolarity and that MEI-1 promotes pole assembly both by severing microtubules and by recruiting ASPM-1. More recently, we have found that klp-7 is required for maintaining bipolarity in the meiotic spindle by preventing the number of poles that can form. In klp-7(-) mutants, we observed in addition to extraneous poles an excess accumulation of microtubules during Meiosis I. Futhermore, reducing klp-7 function can restore bipolarity in a klp-18(-) monopolar spindle mutant background. We also observed that disruption of the kinetochore factor KNL-1 in klp-7(-) mutants exacerbates the extra spindle pole phenotype. We suggest that in oocyte meiosis, klp-7 is required to limit microtubule accumulation and pole assembly and that it may carry out these functions in a kinetochore-dependent manner. This dissertation includes previously published co-authored material. Close

• 49. [Article] Synthesis and Characterization of Rotationally Disordered Intergrowths Containing PbX and TiX2 (X = Se and Te)

  The method of modulated elemental reactants (MER) is used to prepare the layered compound Ti1+xSe2. Using a thin-film precursor prepared by sequentially depositing elemental titanium and selenium by ...

  Citation × Citation Citation Abstract Copy Title: Synthesis and Characterization of Rotationally Disordered Intergrowths Containing PbX and TiX2 (X = Se and Te) Author: Moore, Daniel Year: 2015 The method of modulated elemental reactants (MER) is used to prepare the layered compound Ti1+xSe2. Using a thin-film precursor prepared by sequentially depositing elemental titanium and selenium by physical vapor deposition, the binary compound is readily formed by short-duration annealing at 350°C. The structural and electrical properties of this compound are investigated and suggest that the film is markedly different from the bulk crystalline material. The synthesis is then expanded to produce the first TiSe2 turbostratically disordered misfit layer compound, (PbSe)1.16TiSe2. With the synthesis technique established, the second compound in this family, (PbSe)1.18(TiSe2)2, was synthesized and compared to the misfit layer compound synthesized by bulk methods. The rotationally disordered compound demonstrated an increased Seebeck coefficient and reduced resistivity at room temperature, sparking interest in this family of compounds as potential thermoelectric materials. Designed synthesis of several targeted compounds is reported with interest in evaluating thermoelectric potential of these rotationally disordered compounds. The first nine members of this family were synthesized with m and n values 1 - 3 and evaluated for their thermoelectric properties. Results from this study indicated compounds with larger n values could be of further interest and many more of these compounds are synthesized and reported. Designed synthesis using the MER synthesis method is then pushed further to synthesize the first telluride misfit layer compounds. Four new compounds of the [(PbTe)1.17]m(TiTe2)n family are reported, and their structures were examined by a variety of X-ray diffraction techniques. The robustness of the MER method is revealed by the synthesis of these layered intergrowths which would not be possible using other synthesis methods available. This work consists, in part, of previously published and coauthored material. Title: Synthesis and Characterization of Rotationally Disordered Intergrowths Containing PbX and TiX2 (X = Se and Te) Author: Moore, Daniel Year: 2015 The method of modulated elemental reactants (MER) is used to prepare the layered compound Ti1+xSe2. Using a thin-film precursor prepared by sequentially depositing elemental titanium and selenium by physical vapor deposition, the binary compound is readily formed by short-duration annealing at 350°C. The structural and electrical properties of this compound are investigated and suggest that the film is markedly different from the bulk crystalline material. The synthesis is then expanded to produce the first TiSe2 turbostratically disordered misfit layer compound, (PbSe)1.16TiSe2. With the synthesis technique established, the second compound in this family, (PbSe)1.18(TiSe2)2, was synthesized and compared to the misfit layer compound synthesized by bulk methods. The rotationally disordered compound demonstrated an increased Seebeck coefficient and reduced resistivity at room temperature, sparking interest in this family of compounds as potential thermoelectric materials. Designed synthesis of several targeted compounds is reported with interest in evaluating thermoelectric potential of these rotationally disordered compounds. The first nine members of this family were synthesized with m and n values 1 - 3 and evaluated for their thermoelectric properties. Results from this study indicated compounds with larger n values could be of further interest and many more of these compounds are synthesized and reported. Designed synthesis using the MER synthesis method is then pushed further to synthesize the first telluride misfit layer compounds. Four new compounds of the [(PbTe)1.17]m(TiTe2)n family are reported, and their structures were examined by a variety of X-ray diffraction techniques. The robustness of the MER method is revealed by the synthesis of these layered intergrowths which would not be possible using other synthesis methods available. This work consists, in part, of previously published and coauthored material. Close

• 50. [Article] Investigating Variation in Coral Reef Morphology with Photomosaics and Analysis of Percent Cover

  42 pages

  Citation × Citation Citation Abstract Copy Title: Investigating Variation in Coral Reef Morphology with Photomosaics and Analysis of Percent Cover Author: Culman, Justin Year: 2017 42 pages Title: Investigating Variation in Coral Reef Morphology with Photomosaics and Analysis of Percent Cover Author: Culman, Justin Year: 2017 42 pages Close