Physical Sciences and Mathematics Commons^™

Signature Of Recent Sediment Accumulating In Prince William Sound, Alaska: A Record Of Storms, Earthquakes, And Seasonal Inputs, Nicole R. Marshall

Dissertations, Theses, and Masters Projects

This study focuses on the development o f provenance signatures for sediments accumulating in Prince William Sound, with an emphasis on interpreting mechanisms of sediment deposition using historical earthquake, wave, river discharge, and glacial outburst flood records. A highresolution sedimentary sequence in Prince William Sound, Alaska contains sediments sourced from local watersheds as a result of seasonal and event-driven sedimentation. This study contributes to the development of paleo-proxies for sediment provenance, earthquakes, shelf sediment resuspension, and Copper River discharge. Geochemical studies of sediment cores and end-member samples using X-ray fluorescence and inductively coupled plasma mass spectrometry allows for the development …

Determining The Efficacy Of The Extended Kinetic Method For Determination Of Thermochemical Properties Of Small, High-Entropy, Organic Molecules, Mary Grace Pisano

Dissertations, Theses, and Masters Projects

No abstract provided.

The Influence Of Environmental Factors And Resource Availability On Zostera Marina Flowering Intensity, Andrew J. Johnson

Dissertations, Theses, and Masters Projects

Sexual reproduction and the production of seeds are important for the resilience of all angiosperm species. For clonal species, such as the seagrass Zostera marina, resource allocation is complicated because these species reproduce both asexually and sexually, and the factors contributing to allocation to these two processes remains unknown. The goal of this study was, therefore, to investigate the importance of critical light, nutrient, and rhizome resources on Z.

marina sexual reproduction and flowering intensity. To evaluate the importance of sediment nutrients on Z. marina flowering intensity two distinct field manipulative experiments and one field survey were initiated: 1. Sediments …

Developing Methodologies For Studying Elasmobranchs And Other Data-Poor Species, Kristen L. Omori

Dissertations, Theses, and Masters Projects

Fisheries have become increasingly important to manage and conserve, and this is particularly challenging for data-poor species. Elasmobranchs are commonly considered data-poor or data-limited species. Their life history characteristics make their populations susceptible to depletion from fishing pressures and habitat degradation. Thus, it is important to understand the movement patterns and habitat use of the targeted species as well as the models used in the stock assessment for the species. This thesis involves developing techniques and information for data-poor species, such as elasmobranchs. The objectives of this research were to 1) identify the wintering grounds for the cownose rays (Rhinoptera …

The Influence Of Zostera Marina And Ruppia Maritima On Habitat Structure And Function In A Changing Environment In The Chesapeake Bay, Emily D. French

Dissertations, Theses, and Masters Projects

Seagrasses modify the coastal areas they occupy by trapping sediments and improving water clarity, providing habitat for marine animals, and cycling nutrients. Populations are in decline worldwide, and in the lower Chesapeake Bay, U.S., Zostera marina populations are decreasing due to poor water quality and high summertime temperatures. Ruppia maritima, a seagrass that is smaller, but has a greater tolerance of high temperatures than Z. marina, is replacing Z. marina in some areas. This study examined bed characteristics and microbial community structures of each seagrass species, as well as mixed assemblages, at three sites in the lower Chesapeake Bay where …

Diel, Seasonal, And Interannual Patterns In Mesozooplankton Abundance In The Sargasso Sea, Jami Alora Ivory

Dissertations, Theses, and Masters Projects

Temporal changes in mesozooplankton community structure are influenced by a combination of environmental factors. Epipelagic mesozooplankton biomass in the Sargasso Sea has increased over the last two decades, with a related increase in zooplankton-mediated carbon export. Unknown, however, are the patterns and variability at different temporal scales (diel, seasonal, and interannual) in abundance of each major zooplankton taxon, and how these patterns relate to physical and other environmental changes. I enumerated major taxa of mesozooplankton collected from monthly day and night net tows in the epipelagic zone at the Bermuda Atlantic Time-series Study (BATS) site in the Sargasso Sea from …

Human Induced Cyclical Erosion Due To Altered Sediment Bypassing Mechanisms Of A Barrier Island And The Resultant Impact On The Housing Market, Andrew R. Fallon

Dissertations, Theses, and Masters Projects

No abstract provided.

Noble Metal Free Catalysts For Hydrogen Generation From Aqueous Solutions, Dan Liu

Dissertations, Theses, and Masters Projects

The current energy crisis is becoming more and more serious due to the industrial development and increasing population. Mimicking photosynthesis in plants provides a new way to solve this crisis. The goal is to harness solar energy and convert it into energy stored in chemical bonds such as methanol or hydrogen gas. Currently, most catalysts for proton reduction contain precious metals, such as palladium, platinum and ruthenium. The main goal of our research is to develop catalysts made of earth abundant metals. By incorporating organic ligands in our complexes, we can make catalysts that have similar catalytic activity as those …

Ultracold Rubidium And Potassium System For Atom Chip-Based Microwave And Rf Potentials, Austin R. Ziltz

Dissertations, Theses, and Masters Projects

In this dissertation we study the development of microwave and RF near-field potentials for use with atom chip trapped atomic gases. These potentials are inherently spin-dependent, able to target individual spin states simultaneously. In contrast with traditional atom chip potentials, these RF traps can be operated at arbitrary bias magnetic field strengths and thus be combined with magnetic Feshbach resonances. Furthermore, these potentials can strongly suppress the potential roughness that plagues traditional atom chip potentials. We present a dual chamber atom chip apparatus for generating ultracold 87Rb and 39K atomic gases. The apparatus produces quasi-pure Bose-Einstein condensates of 104 87Rb …

Enabling Parallel Execution Via Principled Speculation., Zhijia Zhao

Dissertations, Theses, and Masters Projects

No abstract provided.

Assessing The Impact Of Climate Change On Proposed Restoration Of The Lynnhaven River Ecosystem, Emily E. Skeehan

Dissertations, Theses, and Masters Projects

Environmental degradation of the Chesapeake Bay (CB) and its sub-estuaries has been linked to population growth in the surrounding coastal zone, rapid development in the watershed and resultant nutrient loading into the Bay. Consequently, the federal government and its partners have developed restoration plans to mitigate the effects of eutrophication and improve essential ecosystem functions, though few restoration plans have considered the interactive effects of climate change. Climate change and other anthropogenic drivers are causing changes in ecosystem structure and function, thereby impacting the beneficial services ecosystems provide. While some studies have attempted to quantitatively predict the benefits of ecosystem …

Surface-Enhanced Raman And Single-Molecule Spectroscopy Studies Of Fugitive Artists' Pigments, Kristen A. Frano

Dissertations, Theses, and Masters Projects

No abstract provided.

Bay Scallop, Argopecten Irradians, Restoration In The Virginia Coastal Bays: The Role Of Predation On Spring Vs Fall Cohort Survival, Erika L. Schmitt

Dissertations, Theses, and Masters Projects

While the importance o f predation in controlling many natural bivalve populations is well established, it is often overlooked in the restoration strategies for depleted populations. Adult bay scallops {Argopecten irradians concentricus) along the U.S. mid-Atlantic coast spawn multiple times per year, typically once in the early summer and again in the early fall. Larvae generally settle on seagrass leaves to avoid benthic predators, but shift to the sediment surface around 20 mm in size when they become less vulnerable to predation. The objectives o f this study were to 1.) Determine proportional survival o f two distinct size classes …

The Influence Of Short-Term Events On The Hydrographic And Biological Structure Of The Southwestern Ross Sea, Randolph M. Jones

Dissertations, Theses, and Masters Projects

Relative to the rest of the Southern Ocean, the Ross Sea continental shelf experiences very high productivity and phytoplankton biomass, which supports an extensive food web including high concentrations of upper trophic level biomass. Conventional observational methods, including ship-based sampling, instrumented moorings, satellite imagery, and computer-based modelling, have illustrated the seasonal progression of the phytoplankton bloom over the past four decades. While we have been sampling phytoplankton variability in the Ross Sea on a variety of relatively large scales, with observations at specific locations or times, over spans of time, or at specific depths, our understanding of smaller scales of …

Optical Characterization Of Ferromagnetic And Multiferroic Thin-Film Heterostructures, Xin Ma

Dissertations, Theses, and Masters Projects

This thesis presents optical characterization of the static and dynamic magnetic interactions in ferromagnetic and multiferroic heterostructures with time-resolved and interface-specific optical techniques. The focus of the thesis is on elucidating the underlying physics of key physical parameters and novel approaches, crucial to the performance of magnetic recording and spintronic devices.;First, time-resolved magneto-optical Kerr effect (TRMOKE) is applied to investigate the spin dynamics in L10 ordered FePt thin films, where perpendicular magnetic anisotropy Ku and intrinsic Gilbert damping alpha0 are determined. Furthermore, the quadratic dependence of Ku and alpha0 on spin-orbit coupling strength xi is demonstrated, where xi is continuously …

Heavy Flavor Interactions And Spectroscopy From Lattice Quantum Chromodynamics, Zachary S. Brown

Dissertations, Theses, and Masters Projects

In the present work, spectroscopy and interactions of hadrons containing heavy quarks is investigated. In particular, a focus is placed on properties of exotic heavy hadronic states, including doubly and triply heavy baryons and doubly heavy tetraquark states. The framework in which these calculations are carried out is provided by lattice quantum chromodynamics, a discrete formulation of the modern theory of the strong interaction. The main body of the thesis had two main project focuses. For the first project, an extensive calculation of the mass spectrum of doubly and triply heavy baryons including both charm and bottom quarks is carried …

Spread And Interaction Of Epidemics And Information On Adaptive Social Networks, Yunhan Long

Dissertations, Theses, and Masters Projects

The spread of diseases and opinions has profoundly affected the development of human societies. The structure of the underlying social network may change as a result of individuals changing their social connections in response to an ongoing epidemic or opinion spreading, either for self protection or as an expression of personal values. The interaction of spreading processes and the underlying network structure has been a focus of many recent studies. In this dissertation, we construct models to better incorporate heterogeneous responses to disease spread and attempted opinion spread.;We first model the simultaneous spread of an epidemic and awareness about the …

Electronic Properties Of Chiral Two-Dimensional Materials, Christopher Lawrence Charles Triola

Dissertations, Theses, and Masters Projects

In this dissertation we study the electronic properties of certain two-dimensional chiral electron systems. We study the static and dynamic screening of gapped bilayer graphene and find important qualitative differences between the dielectric screening function obtained using a simplified 2-band model and that obtained using a more sophisticated 4-band model. We also formulate a continuum model to study the low-energy electronic properties of heterostructures formed by graphene on a strong three-dimensional topological insulator (TI) both for the case of commensurate and incommensurate stacking. We find that the proximity of the TI induces a strong enhancement of the spin-orbit coupling in …

Providing Efficient Services For Smartphone Applications, Yifan Zhang

Dissertations, Theses, and Masters Projects

Mobile applications are becoming an indispensable part of people's lives, as they allow access to a broad range of services when users are on the go. We present our efforts towards enabling efficient mobile applications in smartphones. Our goal is to improve efficiency of the underlying services, which provide essential functionality to smartphone applications. In particular, we are interested in three fundamental services in smartphones: wireless communication service, power management service, and location reporting service.;For the wireless communication service, we focus on improving spectrum utilization efficiency for cognitive radio communications. We propose ETCH, a set of channel hopping based MAC …

Internally Hydrogen-Bonded Prodan Derivatives, Douglas William Cheek

Dissertations, Theses, and Masters Projects

No abstract provided.

A Mathematical Model Of Tau Protein Hyperphosphorylation: The Effects Of Kinase Inhibitors As A Theoretical Alzheimer's Disease Therapy, Patrick Neil Blank

Dissertations, Theses, and Masters Projects

No abstract provided.

Development Of Boron-Containing Polyimide Materials And Poly(Arylene Ether)S For Radiation Shielding, Brittani May Collins

Dissertations, Theses, and Masters Projects

No abstract provided.

Two-Component, Four Reaction Domino Sequence Toward Novel Tricyclic 1,4-Dihydro-2h-Benzo(F)Sochromenes, Yuzhou Chen

Dissertations, Theses, and Masters Projects

The synthesis of complex molecules usually

Advancing Feedback-Driven Optimization For Modern Computing., Mingzhou Zhou

Dissertations, Theses, and Masters Projects

No abstract provided.

Sterile Neutrino Search With Minos., Alena V. Devan

Dissertations, Theses, and Masters Projects

No abstract provided.

Studies Of Molecular Dynamics Of Fmoc Amino Acids Using Solid State Deuteron Nuclear Magnetic Resonance Spectroscopy, Wei Xu

Dissertations, Theses, and Masters Projects

The purpose of devising and validating models for intramolecular motions for FMOC amino acids is to quantify side chain motion in proteins which plays an important role in understanding biological structure function relations of proteins. In this thesis, spin lattice relaxation times (Ti) of FMOC amino acids were m easured under both static and magic angle spinning (MAS) condition at variable tem peratures. Lower activation energies of the relaxation times than the normal amino acids observed indicate a less sterically crowded environment for the rotation methyl group. A three-site jump model for the methyl group w as developed to fit …

The Reproductive Biology Of Striped Bass (Morone Saxatilis) In Chesapeake Bay, Carissa L. Gervasi

Dissertations, Theses, and Masters Projects

The Striped Bass (Morone saxatilis) is an anadromous finfish that supports a lucrative fishery along the Atlantic coast of the United States and serves as a vital component of estuarine food webs. Once Striped Bass stocks were restored after crashing in the late 1980s, abundance skyrocketed to record levels. Over the past decade however, abundance has steadily declined, concurrent with an outbreak of mycobacteriosis. Disease prevalence is currently >50%, and previous research has demonstrated diseasepositive fish exhibit slower growth and increased natural mortality compared to diseasenegative fish. The purpose of this research was to provide a contemporary description of Chesapeake …

Mercury Reduces Avian Reproductive Success Through Direct Embryotoxicity Rather Than Altered Parental Behavior, Stephanie Yen Chin

Dissertations, Theses, and Masters Projects

No abstract provided.

A Model Of Carrying Capacity And Ecosystem Impacts In A Large-Scale, Bivalve-Dominated Agro-Ecosystem: Hard Clam Aquaculture In Cherrystone Inlet, Va, Michael A. Kuschner

Dissertations, Theses, and Masters Projects

With the recent growth of the hard clam aquaculture industry, sites of intensive aquaculture have emerged as large-scale agro-ecosystems where the success of aquaculture production is dynamically linked to ecosystem function. Large scale clam aquaculture operations are associated with a range of potential positive and negative feedbacks related to nutrient dynamics, water and sediment quality, proliferation of macroalgae, and carrying capacity. Quantitative modeling tools are needed to support system-level planning related to site selection, scale of operations, production capacity and ecosystem function. The purpose of this study was to develop a model for Cherrystone Inlet, VA, where one-third (1.9 km2) …

Storm Event Impact On Organic Matter Flux, Composition And Reactivity In Taskinas Creek, Va, Sarah Schillawski Cammer

Dissertations, Theses, and Masters Projects

Carbon export from the land to the ocean are an important part of the global carbon cycle, linking terrestrial watersheds and the global carbon cycle. Burial of terrestrial organic carbon represents a long term sink for atmospheric CO2. Approximately 0.4 Pg Cy-1 is delivered to the global ocean from rivers, equally divided between POC and DOC. However, the amount of carbon entering the ocean is a small portion of the total amount entering rivers from the terrestrial environment, suggesting a large amount of processing in inland waters and estuaries. Most monitoring efforts have focused the processing of organic matter on …