Physics Commons^™

First-Principles Simulations Of Materials Under Extreme Conditions, Kien Nguyen Cong

USF Tampa Graduate Theses and Dissertations

The investigation of materials at extreme conditions of high pressure and temperature (high-PT), has been one of the greatest scientific endeavors in condensed mater physics, chemistry, astronomy, planetary, and material sciences. Being subjected to high-PT conditions, materials exhibit dramatic changes in both atomic and electronic structure resulting in an emergence of exceptionally interesting phenomena including structural and electronic phase transitions, chemical reactions, and formation of novel compounds with never-previously observed physical and chemical properties. Although new exciting experimental developments in static and dynamic compression combined with new diagnostics/characterization methods allow to uncover new processes and phenomena at high P-T conditions, …

Millimeter-Wavelength Characterization Of The Co Emission Of Comets 174p/Echeclus, 29p/Schwassmann-Wachmann, And C/2016 R2 (Panstarrs), Kacper Wierzchos

USF Tampa Graduate Theses and Dissertations

Comets are fascinating minor solar system bodies. They contain some of the most pristine and unprocessed material found in the solar system. As a comet approaches the Sun it displays the characteristic cometary coma and tail. This is due to the release of volatile species through a variety of processes. In the present work I studied the carbon monoxide emission of three very unique comets; 174P/Echeclus, 29P/Schwassmann-Wachmann and C/2016 R2 (PanSTARRS) with different radio telescopes at millimeter wavelengths. After molecular hydrogen, carbon monoxide is the second most abundant molecule in the universe, and is also the most volatile of the …

Measuring And Utilizing High-Dimensional Information Of Optical Fields, Ziyi Zhu

USF Tampa Graduate Theses and Dissertations

Currently, many areas of optical techniques including imaging, inspection and communication emphasize the utilization of the high-dimensional information encoded in optical fields. There is also a requirement for novel measurement techniques to extract this high-dimensional information with high-speed and accuracy. We firstly introduce a scan-free direct measurement technique that is capable of simultaneously characterizing the amplitude and phase of a coherent scalar optical field. Our direct measurement approach is constituted of a weak polarization perturbation which is followed by the recording of a polarization-resolving imaging process. The weak perturbation rotates the linear polarization on the spatial frequency domain of the …

Modulations Of Lipid Membranes Caused By Antimicrobial Agents And Helix 0 Of Endophilin, Nawal Kishore Khadka

USF Tampa Graduate Theses and Dissertations

Understanding the cellular membrane interaction with membrane active biomolecules and antimicrobial agents provides an insight in their working mechanism. Here, we studied the effect of antimicrobial agents; a recently developed peptidomimetics E107-3 and colistin as well as the N-terminal helix H0, of Endophilin A1 on the lipid bilayer.

It is important to discern the interaction mechanism of antimicrobial peptides with lipid membranes in battling multidrug resistant bacterial pathogens. We study the modification of structural and mechanical properties with a recently reported peptidomimetic on lipid bilayer. The compound referred to as E107-3 is synthesized based on the acylated reduced amide scaffold …

Water And Salt At The Lipid-Solvent Interface, James M. Kruczek

USF Tampa Graduate Theses and Dissertations

Lipid bilayers are important biological structures. The changes in bilayer properties are induced by the composition of the bilayer as well as the solvent. In this work, we study the effects of different molecular makeups of lipids and ionic solvents with molecular dynamics simulations to determine their effect on the bilayer interface. In particular, we look at how different carbon chain bindings affect water viscosity at the interface and allow for a less permeable bilayer. Additionally, we examine the changes to the bilayer due to the presence of the most biologically relevant salt ions. Lastly, we show how the pharmacological …

Phase Evolution And Dynamic Behavior In Materials With Noncollinear Spin Textures, Eleanor M. Clements

USF Tampa Graduate Theses and Dissertations

Noncentrosymmetric magnetic materials have gained special attention due to their ability to stabilize topologically nontrivial magnetic states via the competition between symmetric exchange and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction. The spin struc- tures in these materials have become a center of interest for spintronics applications due to their stable, particle-like properties, and high degree of tunability via control of external parameters, such as magnetic and/or electric field and temperature. Understanding how these robust magnetic structures stabilize, evolve, dynamically respond, and adhere to existing models, all in the presence of external stimuli, are topics of fundamental interest. In this dissertation, the …

Exploring Variations In Diet And Migration From Late Antiquity To The Early Medieval Period In The Veneto, Italy: A Biochemical Analysis, Ashley B. Maxwell

USF Tampa Graduate Theses and Dissertations

This project tests the hypothesis that the Langobard migration into the Roman/Byzantine Veneto (northeastern Italy) resulted in significant dietary changes from Late Antiquity (4-5th centuries AD) to the Early Medieval period (6-8th centuries AD). At the end of the Great Germanic Migrations in AD 568, Langobards from Pannonia entered and occupied two-thirds of the Italian peninsula. It is unclear how large these migrations were, as historical documents exaggerate mass movements; however, conservative estimates suggest they made up 8% of the areas they occupied. The degree to which the Langobards influenced economic change and subsistence in this area is poorly understood. …

Estimating Coastal Water Turbidity Using Viirs Nighttime Measurement, Chih-Wei Huang

USF Tampa Graduate Theses and Dissertations

Coastal water turbidity is a key environmental factor that influences the relative clarity of the water, which therefore reduces sunlight penetration. The comprehensive spatial and temporal coverage of remote sensing allows mapping of water turbidity near the coast. Even in locations where time-consuming and expensive conventional turbidity monitoring programs exist, local technological limitations prevent complete coverage. Traditional optical satellite techniques using the visible band also have limitations in monitoring turbidity due to non-optimal observing conditions such as clouds, sun-glint, and thick aerosols. In this study, in order to complement the daytime satellite measurements, I used the data from Visible Infrared …

Tip-Enhanced Nano-Optical Imaging Of Superacid Treated Bilayer Mos2-Ws2 2d Lateral Heterostructures, Amala Dixit

USF Tampa Graduate Theses and Dissertations

Nanoscale optical characterization of two-dimensional (2D) materials and heterostructures is important for the design of novel optoelectronic flexible nano-devices. Nano-optical photoluminescence (PL) and Raman imaging of bilayer 2D materials has been a challenging problem due to weak signals. The exciton-dominated light emission of two-dimensional (2D) transition metal dichalcogenide (TMDC) materials is affected by the formation of defects and doping states. Previous studies have shown that chemical treatment modifies the defect and doping states of chemical vapor deposition (CVD)-grown monolayers of MoS₂ and WS₂, which provides a promising possibility for engineering the optoelectronic properties of these 2D TMDCs. …