Engineering Commons^™

Nonlinear Dielectric Behavior Of Field-Induced Antiferroelectric/Paraelectric-To-Ferroelectric Phase Transition For High Energy Density Capacitor Application, Mingyang Li

Dissertations, Master's Theses and Master's Reports

Electric field-induced antiferroelectric(AFE)/paraelectric(PE)-to-ferroelectric(FE) phase transitions are investigated for the associated nonlinear dielectric behavior, which could offer high dielectric capacity. The phenomenon in monolithic materials has been computed for Kittel antiferroelectric and BaTiO₃ model systems using the Landau-Ginzburg-Devonshire theory. The general switching curves give values of the polarization as a function of external electric field. A similar computation is performed for particle-filled polymer-matrix composites where an internal depolarization field is considered. The polarization-electric field response changes with different depolarization factors, which demonstrate the shape and alignment of the dielectric particles embedded in polymer-matrix are key factors for the composite to …

Influence Of Magnetic Nanoparticles And Magnetic Stress On An Ionic Liquid Electrospray Source, Kurt Joseph Terhune

Dissertations, Master's Theses and Master's Reports

Two electrospray sources were developed to operate on an ionic liquid ferrofluid; one source was a pressure‑fed capillary electrospray source and the other was a novel electrospray source which used a magnetically‑induced instability to produce a peak from which an electric field could extract electrospray. Multiple characteristics of electrospray operation were examined for both sources using faraday plates/cups, a quartz crystal microbalance, a retarding potential analyzer, and a time-of-flight mass spectrometer. The ILFF electrosprays for a capillary source were shown to operate in a mixed ion/droplet regime. The mass flow of the electrospray beam was primarily transported by larger particles …

Detecting Overpressure Zones By Using Model Based Inversion In Kupe Field, New Zealand, Timucin Cakir

Dissertations, Master's Theses and Master's Reports

Overpressure is a significant parameter during a drilling process in oil exploration. This phenomenon happens when pore pressure exceeds the limit of hydrostatic pressure in a formation and causes drastic hazards such as blow outs while drilling. This thesis focuses on the determination of possible overpressure areas and studies at three wells in Kupe Field, which is considered to be a natural-gas field in Taranaki Basin. In an effort to identify potential overpressure zones at the Kupe Field, acoustic impedance responses of 3D seismic data for three wells, along with their well log responses were evaluated.

Seismic inversion plays an …

Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian

Dissertations, Master's Theses and Master's Reports

Anthropocentric water resources management affects aquatic habitats by changing streamflow regime. Understanding the impacts of water withdrawal from different sources and consumption by various economic sectors at different spatial and temporal scales is key to characterizing ecologically harmful streamflow disturbances. To this end, we developed a generic, integrative framework to characterize catchment scale water stress at annual and monthly time scales. The framework accounts for spatially cumulative consumptive and non-consumptive use impacts and associated changes in flow due to depletion and return flow along the stream network. Application of the framework to the U.S. Great Lakes Region indicates that a …

Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale

Dissertations, Master's Theses and Master's Reports

In the past century, extensive research has been done regarding the sound propagation in arctic ice sheets. The majority of this research has focused on low frequency propagation over long distances. One of the most commonly used excitation methods for air-ice-water layers has been explosives. However, environmental regulation has become more stringent, disallowing the use of almost all explosive excitation types. Due to changing climate conditions in these environments, new experimentation is warranted to determine sound propagation characteristics in, through, and under thin ice sheets, in shallow water, over short distances. In April, 2016 several experiments were conducted approximately 2 …