Doctor of Philosophy, Miami University, 2025, Chemistry and Biochemistry

The purpose of this dissertation is to observe physical properties of molecules in solution. Structural dynamics information is provided for three systems: a cobalt-centered complex converting between three coordination states at low temperature, a lanthanide complex adopting two NMR-active enantiomers according to identity of the metal center, and a chaperone protein interaction determining binding symmetry. These systems are investigated using a variety of analytical methods – including crystallography, NMR spectroscopy, Density Functional Theory calculations, and Molecular Dynamics simulations. Chapter 2 examines the dynamics of TpPh,Me Cobalt (II) NO3 (TpPh,MeCoNO3) [TpPh,Me = tris-3-phenyl-5-methylpyrazolylborate]. Solid-state XRD structure of TpPh,MeCoNO3 is presented for the first time, showing a five-coordinate Co (II) complex with TpPh,Me with NO3 bound as a bidentate ligand. Variable temperature NMR spectra are complicated at low temperature, with signals coalescing as temperature is increased. The high temperature NMR spectra indicate a four-coordinate structure above room temperature. Spectral analysis demonstrates the TpPh,MeCoNO3 complex occupies three concurrent structures at low temperatures. These three structures are analyzed using Density Functional Theory (DFT) calculations of four- and five-coordinate structures generated in silica from the crystal structure. In Chapter 3, the conformational interconversion of two NMR-active LnDOTAM structures (Ln=La-Lu; DOTAM=1,4,7,10-tetrakis(acetamido)-1,4,7,10-tetraaza-cyclododecane) are examined using a series of 13 lanthanide ions. Variable-temperature 1H NMR spectra demonstrate the concentration of the two identifiable conformations in solution depends on the identity of the metal ion. At low temperature, early LnDOTAM (Ce-Nd) have a high concentration of the twisted square antiprismatic geometry (TSAP), and later LnDOTAM (Sm, Eu, Tb-Yb) have a higher concentration of the square antiprismatic geomet (open full item for complete abstract)

Committee: David Tierney (Advisor); Rick Page (Committee Chair); Michael Crowder (Committee Member); Dominik Konkolewicz (Committee Member); Luis Actis (Committee Member) Subjects: Chemistry; Inorganic Chemistry; Molecular Biology; Physical Chemistry

PhD, University of Cincinnati, 2016, Engineering and Applied Science: Engineering Mechanics

Corrosion and erosion damage pose fundamental challenges to operation of oil and gas infrastructure. In order to manage the life of critical assets, plant operators must implement inspection programs aimed at assessing the severity of wall thickness loss (WTL) in pipelines, vessels, and other structures. Maximum defect depth determines the residual life of these structures and therefore represents one of the key parameters for robust damage mitigation strategies. In this context, continuous monitoring with permanently installed sensors has attracted significant interest and currently is the subject of extensive research worldwide. Among the different monitoring approaches being considered, significant promise is offered by the combination of guided ultrasonic wave technology with the principles of model based inversion under the paradigm of what is now referred to as guided wave tomography (GWT). Guided waves are attractive because they propagate inside the wall of a structure over a large distance. This can yield significant advantages over conventional pulse-echo thickness gage sensors that provide insufficient area coverage – typically limited to the sensor footprint. While significant progress has been made in the application of GWT to plate-like structures, extension of these methods to pipes poses a number of fundamental challenges that have prevented the development of sensitive GWT methods. This thesis focuses on these challenges to address the complex guided wave propagation in pipes and to account for parametric uncertainties that are known to affect model based inversion and which are unavoidable in real field applications. The main contribution of this work is the first demonstration of a sensitive GWT method for accurately mapping the depth of defects in pipes. This is achieved by introducing a novel forward model that can extract information related to damage from the complex waveforms measured by pairs of guided wave transducers mounted o (open full item for complete abstract)

Committee: Francesco Simonetti Ph.D. (Committee Chair); Jongguen Lee Ph.D. (Committee Member); Guirong Liu Ph.D. (Committee Member); T. Douglas Mast Ph.D. (Committee Member) Subjects: Acoustics

Doctor of Philosophy, The Ohio State University, 2015, Geological Sciences

The structure, dynamics, and composition of Earth's deep interior have direct control on plate tectonics and surface-to-interior exchange of material, including water and carbon. To properly interpret geophysical data of the Earth's interior, accurate and precise measurements of the material properties of the constituent mineral phases are required. Additionally, experimentally derived data need to be augmented by computational chemistry and modeling of physical properties to elucidate the effect of compositional variations and deep storage of volatile components (e.g. H2O and CO2) within the crystalline phases. This dissertation uses in situ high pressure, high-temperature experiments in the laser-heated diamond anvil cell (LHDAC) coupled with synchrotron-based x-ray diffraction. The thermal expansion and bulk modulus of Ni and SiO2 are measured to P = ~110 GPa and T = ~3000 K. Nickel is a significant component of the Earth's core and SiO2 is the fundamental building block of the Earth's mantle and crust. We have designed the first controlled-geometry samples of Ni and SiO2, manufactured using nanofabrication techniques, and specifically tuned to reduce systematic errors in the measurement. Knowledge of the thermoelastic properties of Ni and SiO2 has implications for subduction rates, plume buoyancy, dynamics of the Earth's convective heat engine, and planetary formation. Complimentary to the Ni/SiO2 experiments, the energetics of different hydrogen defect mechanisms in garnet (MgSiO3-Mg3Al2Si3O12) and associated geophysical properties (P- and S-wave velocities) are calculated using atomistic simulations and first-principles calculations to a depth of 700 km. Garnet accounts for as much as 40 percent of the rock volume at 500 km. By calculating and comparing the defect energies associated with charge-balanced substitutions of hydrogen for magnesium or silicon, the hydrogarnet defect has the lowest energy and is therefore predicted to be the most favorable in the ga (open full item for complete abstract)

Committee: Wendy Panero (Advisor); Berry Lyons (Committee Member); Michael Barton (Committee Member); David Cole (Committee Member) Subjects: Earth; Geological

Doctor of Philosophy, The Ohio State University, 2006, Electrical Engineering

A collective uniform geometrical theory of diffraction (UTD) ray solution is developed for describing the fields radiated by large array apertures that are conformal to a doubly curved, smooth convex PEC surface. Such conformal array apertures may either be physical array apertures formed by simple antenna elements located directly on a convex PEC surface, or be equivalent apertures defined by more complex flush mounted radome-covered antenna arrays whose elements are slightly recessed in a cavity structure just below the skin line of a convex PEC boundary. The present UTD solution describes all at once the radiation from the whole array aperture in terms of just a few rays which are launched from specific critical points in the interior and on the array aperture boundary. Hence, it is relatively highly efficient as compared to the conventional element-by-element field summation approach. More importantly, it provides useful physical insights into the array radiation mechanisms. In most practical applications, the large array is situated conformally on an even larger platform, e.g. an aircraft, a spacecraft, or a naval ship, etc. In these realistic cases, the very large platform part can be modeled efficiently by the high-frequency UTD method, while the large array part can be modeled locally by numerical methods (FEM, FE-BI, etc.). The coupling of the array fields to the external platform is then achieved by the present collective UTD solution which launches the collective ray fields from the array aperture or window to then interact with the rest of the platform. Such a hybrid numerical-collective UTD method provides a useful, tractable and relatively efficient analysis of large arrays on a very large platform. Numerical results are presented to demonstrate the accuracy and efficiency of the present collective UTD ray solution for describing the fields radiated by large conformal antenna phased arrays on a smooth convex PEC surface.

Committee: Prabhakar Pathak (Advisor) Subjects:

Bachelor of Science in Petroleum Engineering, Marietta College, 2013, Petroleum Engineering and Geology

It has been hypothesized that utilizing current well logging practices, with Dual Water Theory, it is possible to identify all minerals within rock formations. The purpose of this study was to develop software that supports this hypothesis. It also was created to demonstrate a hypothesized plotting correlation discovered by Professor Ben Ebenhack. The results show promise in supporting this hypothesis correct, and recommendations for future adjustments to the software are given.

Committee: Ben Ebenhack (Advisor); Robert Van Camp (Committee Member); David Brown (Committee Member) Subjects: Petroleum Engineering; Petroleum Geology