Digital Commons Network^™

Synthesis, Characterization, And Drug Delivery Applications Of Carbohydrate Based Low Molecular Weight Gelators, Kristen Elizabeth Bashaw

Chemistry & Biochemistry Theses & Dissertations

The main aim of the research focuses on the study of self-assembly and gelation by several classes of simple sugar derivatives and the potential applications of them as drug delivery vehicles. Since carbohydrates are naturally abundant renewable resources and are therefore readily available and many of them are inexpensive compared to other raw materials. They are also biocompatible which makes them suitable for a wide variety of applications. Combining the use of carbohydrates with low molecular weight gelators (LMWGs) we can introduce a new class of soft materials that are able to self-assemble into spheres, fibers, sheets, and micelles in …

Sediment Resuspension In A Microtidal Estuary: Causative Forces And Links With Algal Blooms, Samantha C. Mcgill

OES Theses and Dissertations

After years of efforts to restore the Chesapeake Bay, bacterial levels are down and species diversity has increased, however, algal blooms (primarily dinoflagellates) persist, occurring nearly every summer. Dinoflagellates produce resting cysts that accumulate in the bottom sediments and are thought to provide seed populations for future algal blooms when they are resuspended. When estuarine sediments are advected from a bed, other materials, such as pollutants, nutrients, and organic matter are also released into the water column. Thus, resuspended sediments can contribute to the degradation of water quality, habitat, and aquatic life, and impart negative impacts on local ecosystems and …

Circum-Arctic Mineralogy & Pan-Arctic Chronostratigraphy Of Late Pleistocene Sediments: Developing A Comprehensive Age Model For The Western Arctic Ocean Using Unique Ice-Rafted Signals, Wesley Blake Myers

OES Theses and Dissertations

To improve understanding of geographic mineral distribution from the circum-Arctic Ocean, samples from the Arctic periphery were collected and analyzed for (semi-) quantitative mineral composition. Most samples were collected from the North American region of the Arctic Ocean, a region which has had limited mineral investigation. In addition, more than 1000 published clay mineral data points were gathered to provide the most comprehensive clay mineral distribution map to date. The identification of a smectite source within the Canadian Arctic may reduce the usefulness of this mineral as a unique provenance signal for the Eurasian region. Smectite speciation may be useful …

Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, Jeremy J. Peshl

Physics Theses & Dissertations

The plasma processing of superconducting radio-frequency (SRF) cavities has shown significant promise as a complementary or possible replacement for the current wet etch processes. Empirical relationships between the user-controlled external parameters and the effectiveness of Reactive Ion Etching (RIE) for the removal of surface layers of bulk niobium have been previously established. However, a lack of a physical description of the etching discharge, particularly as the external parameters are varied, limits the development of this technology. A full understanding of how these external parameters affect both the amount of material removed and the physical properties of the plasma would aid …

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki

Electrical & Computer Engineering Theses & Dissertations

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J/cm²) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C⁴⁺ are observed. When no acceleration voltage is applied between …

A Cfd Study Of Steady Fully Developed Laminar Flow Through A 90-Degree Bend Pipe With A Square Cross-Sectional Area, Subodh Sushant Toraskar

Mechanical & Aerospace Engineering Theses & Dissertations

Fluid flow through a closed curved conduit has always been a topic of extensive research, as it has many practical and industrial applications. The flow is generally characterized by a presence of secondary flow, vortical motions and pressure losses for different flow regimes. These observed irregularities may positively or negatively impact the flow. They are beneficial for cases where mixing of fluids is required, usually observed for multiphase flow regimes or detrimental for cases involving particles in the fluid. There are also instances where a particle-laden fluid transported through the curved pipe was directly related to corrosion- erosion related problems. …

Demonstration Of Visible And Near Infrared Raman Spectrometers And Improved Matched Filter Model For Analysis Of Combined Raman Signals, Alexander Matthew Atkinson

Electrical & Computer Engineering Theses & Dissertations

Raman spectroscopy is a powerful analysis technique that has found applications in fields such as analytical chemistry, planetary sciences, and medical diagnostics. Recent studies have shown that analysis of Raman spectral profiles can be greatly assisted by use of computational models with achievements including high accuracy pure sample classification with imbalanced data sets and detection of ideal sample deviations for pharmaceutical quality control. The adoption of automated methods is a necessary step in streamlining the analysis process as Raman hardware becomes more advanced. Due to limits in the architectures of current machine learning based Raman classification models, transfer from pure …

Tick Control Methods For Amblyomma Americanum In Virginia: Applications And Modeling, Alexis Lynn White

Biological Sciences Theses & Dissertations

Tick-borne diseases continue to increase in the United States, and yet no comprehensive method of tick control currently exists. The lone star tick, Amblyomma americanum, is an aggressive human-biting tick and vector of several pathogens which effect both humans and other animals. Standard control methods do not work as well for A. americanum as they do for the more commonly studied blacklegged tick, Ixodes scapularis. TickBot, a tick-killing robot, is a potential method to control A. americanum that lures ticks to its path with carbon dioxide and the ticks die from contact with a permethrin-treated cloth that is …

Electrohydrodynamic Simulations Of The Deformation Of Liquid-Filled Capsules, Pai Song

Mathematics & Statistics Theses & Dissertations

A comprehensive two- and three-dimensional framework for the electrohydrodynamic simulation of deformable capsules is provided. The role of a direct current (DC) electric field on the deformation and orientation of a liquid-filled capsule is thoroughly considered numerically. This framework is based on lattice Boltzmann method for the fluid, finite element method for the membrane structure of the capsule, fast immersed interface method for the electric field and immersed boundary method being used to consider the fluid-structure-electric interaction. Under the effect of electric field, two different types of equilibrium states, prolate or oblate are obtained. The numerical algorithm is also applied …

Computational Analysis Of Antipode Algorithms For The Output Feedback Hopf Algebra, Lance Berlin

Electrical & Computer Engineering Theses & Dissertations

The feedback interconnection of two systems written in terms of Chen-Fliess series can be described explicitly in terms of the antipode of the output feedback Hopf algebra. At present, there are three known computational approaches to calculating this antipode: the left coproduct method, the right coproduct method, and the derivation method. Each of these algorithms is defined recursively, and thus becomes computationally expensive quite quickly. This motivates the need for a more complete understanding of the algorithmic complexity of these methods, as well as the development of new approaches for determining the Hopf algebra antipode. The main goals of this …

Pulse Power Effects On Transient Plasma Ignition For Combustion, David Wayne Alderman Ii

Electrical & Computer Engineering Theses & Dissertations

Transient plasma ignition (TPI) uses highly non-equilibrium plasmas, driven by less than 100 nanosecond, high-voltage pulses, to initiate combustion. The effects of pulse repetition frequency (PRF) and ultrashort nanosecond rise times on TPI are investigated in this work using lean, stoichiometric, and rich air-fuel mixtures at atmospheric pressure. Experimental data show the transient plasmas driven by ultrashort rise time, high voltage pulses at high PRF’s enhance the combustion of lean or stoichiometric air-methane mixtures in a static chamber. In particular, increasing PRF enhances the combustion performance by means of reduced delay times independent of the equivalence ratio of the air-fuel …

Global Conservation Status And Threat Patterns Of The World’S Most Prominent Forage Fishes (Teleostei, Clupeiformes), Tiffany L. Birge

Biological Sciences Theses & Dissertations

Conserving biodiversity is one of the greatest ethical responsibilities and challenges humans face. Understanding the conservation status of taxonomic groups provides a systematic way to prioritize efforts to combat biodiversity loss. The 405 species within the order Clupeiformes are the herrings, shads, sardines, anchovies, menhadens and relatives that include many of the most important marine forage fishes. These small, schooling fishes are economically, ecologically and culturally significant globally. Despite their contribution to global fisheries and our increasing reliance on these fishes for food and industrial commodities, they are generally poorly known with limited information regarding basic biology and population trends. …

Communication Capability For A Simulation-Based Test And Evaluation Framework For Autonomous Systems, Ntiana Sakioti

Computational Modeling & Simulation Engineering Theses & Dissertations

The design and testing process for collaborative autonomous systems can be extremely complex and time-consuming, so it is advantageous to begin testing early in the design. A Test & Evaluation (T&E) Framework was previously developed to enable the testing of autonomous software at various levels of mixed reality. The Framework assumes a modular approach to autonomous software development, which introduces the possibility that components are not in the same stage of development. The T&E Framework allows testing to begin early in a simulated environment, with the autonomous software methodically migrating from virtual to augmented to physical environments as component development …

Validation Of Neutrino Energy Estimation Using Electron Scattering Data, Mariana Khachatryan

Physics Theses & Dissertations

To study neutrino oscillations, the knowledge of the initial neutrino energy is required. This energy cannot be determined directly because neutrino beams have a broad energy distribution. Instead, the initial energy for each event is estimated from the final state particles of a neutrino-nucleus interaction using two main approaches. It can be determined either from the total energy of all the final state particles or, if the neutrino scatters quasi-elastically from a bound nucleon, then the initial energy can be calculated approximately using the scattered angle and energy of the outgoing charged lepton. This requires a detailed understanding of neutrino-nucleus …

Spatiotemporal Downscaling Rainfall Predictions Of North American Regional Climate Change Assessment Program For Entire Virginia, Zhaoyi Cai

Civil & Environmental Engineering Theses & Dissertations

This thesis developed a statistical downscaling approach, which consists of a series of linear regression equations, to spatiotemporally downscale the rainfall predictions from North American Regional Climate Change Assessment Program (NARCCAP) in accordance with the 15-min observed rainfall data at the rain gauges across the state of Virginia. NARCCAP has generated twelve different region-global climate models (RCM-GCMs) with a temporal resolution of 3 hr and a spatial resolution of 50 km over the entire America. Although it has been downscaled already, such resolutions are still too coarse to represent the rain gauges. This means that the RCM-GCMs’ predictions need to …

Catalytic Transfer Hydrogenation Reactions Of Lipids, Alexander Asiedu

Civil & Environmental Engineering Theses & Dissertations

Catalytic transfer hydrogenation (CTH) of lipids was investigated using 2-propanol as hydrogen donor for producing liquid hydrocarbons, e.g. jet fuels. The main sources of lipids selected in this study were waste cooking oil (WCO) and oil-laden algae-derived biofuel intermediate (BI). Two different catalysts were employed in this study, namely activated carbon and trimetallic-doped zeolite.

The CTH reaction was between WCO and 2-propanol in a continuous flow reactor over a packed-bed activated carbon at near atmospheric pressure. Results revealed a high level of alkenes and aromatics compounds, which are not stable and are not environmentally unfriendly. To reduce these compounds in …

Nutrient Controls Over Cyanobacterial Synthesis Of The Neurotoxin Β-N-Methylamino-L-Alanine (Bmaa) And Its Potential Accumulation In The Blue Crab (Callinectes Sapidus), Madeline M. Hummel

OES Theses and Dissertations

Cyanobacteria are known to produce a variety of toxins that negatively impact both aquatic and terrestrial organisms. One putative neurotoxic compound is the non-protein amino acid β-N-methylamino-L-alanine (BMAA), which has epidemiological linkages to the development of several human neurological diseases. Three cyanobacterial species thought to produce BMAA —Microcystis aeruginosa, Synechococcus bacillaris, and Nostoc sp. —were grown in nutrient replete cultures to examine its synthesis and cellular distribution over a growth cycle. Production of BMAA was also examined in nutrient (nitrogen and phosphorus) deplete cultures of Microcystis aeruginosa. In addition, natural assemblages of phytoplankton dominated by …

The Evolution Of The El Niño-Southern Oscillation And Tropical Pacific Climate Across The Last Deglaciation, Ryan Hunter Glaubke

OES Theses and Dissertations

The El Niño – Southern Oscillation (ENSO) is the largest interannual component of Earth’s climate system, capable of exerting significant influence over global climate patterns that affect communities around the globe. Nevertheless, a comprehensive understanding of the ENSO system and its relationship to tropical Pacific climate dynamics remains unclear. Although new paleoceanographic proxies have shown promise in in their ability to constrain past ENSO change, little is known about how ENSO varied in response to millennial-scale climate events over the last 25,000 years. Here, I present new records of tropical Pacific mean state and ENSO variability over the last 25,000 …

Copula-Based Zero-Inflated Count Time Series Models, Mohammed Sulaiman Alqawba

Mathematics & Statistics Theses & Dissertations

Count time series data are observed in several applied disciplines such as in environmental science, biostatistics, economics, public health, and finance. In some cases, a specific count, say zero, may occur more often than usual. Additionally, serial dependence might be found among these counts if they are recorded over time. Overlooking the frequent occurrence of zeros and the serial dependence could lead to false inference. In this dissertation, we propose two classes of copula-based time series models for zero-inflated counts with the presence of covariates. Zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB), and zero-inflated Conway-Maxwell-Poisson (ZICMP) distributed marginals of the …

Using Feature Extraction From Deep Convolutional Neural Networks For Pathological Image Analysis And Its Visual Interpretability, Wei-Wen Hsu

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents a computer-aided diagnosis (CAD) system using deep learning approaches for lesion detection and classification on whole-slide images (WSIs) with breast cancer. The deep features being distinguishing in classification from the convolutional neural networks (CNN) are demonstrated in this study to provide comprehensive interpretability for the proposed CAD system using the domain knowledge in pathology. In the experiment, a total of 186 slides of WSIs were collected and classified into three categories: Non-Carcinoma, Ductal Carcinoma in Situ (DCIS), and Invasive Ductal Carcinoma (IDC). Instead of conducting pixel-wise classification (segmentation) into three classes directly, a hierarchical framework with the …

Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown

OES Theses and Dissertations

The Ganges-Brahmaputra-Meghna (GBM) Delta is one of the largest deltas in the world, covering more than 100,000 km². The GBM River system transports over one billion tons of sediment annually and delivers ~750 million tons to the Bay of Bengal, ~25% of which is advected by tides into the fluvially abandoned western delta plain. The Sundarbans National Forest (SNF) is located within the GBM Delta and, covering more than 10,000 km², is the world’s largest continuous mangrove stand. The present rate of sediment delivery allows the SNF platform elevation to keep pace with regional sea level …

Aggregating Private And Public Web Archives Using The Mementity Framework, Matthew R. Kelly

Computer Science Theses & Dissertations

Web archives preserve the live Web for posterity, but the content on the Web one cares about may not be preserved. The ability to access this content in the future requires the assurance that those sites will continue to exist on the Web until the content is requested and that the content will remain accessible. It is ultimately the responsibility of the individual to preserve this content, but attempting to replay personally preserved pages segregates archived pages by individuals and organizations of personal, private, and public Web content. This is misrepresentative of the Web as it was. While the Memento …

Scalable Parallel Delaunay Image-To-Mesh Conversion For Shared And Distributed Memory Architectures, Daming Feng

Computer Science Theses & Dissertations

Mesh generation is an essential component for many engineering applications. The ability to generate meshes in parallel is critical for the scalability of the entire Finite Element Method (FEM) pipeline. However, parallel mesh generation applications belong to the broader class of adaptive and irregular problems, and are among the most complex, challenging, and labor intensive to develop and maintain. In this thesis, we summarize several years of the progress that we made in a novel framework for highly scalable and guaranteed quality mesh generation for finite element analysis in three dimensions. We studied and developed parallel mesh generation algorithms on …

Early Information Access To Alleviate Emergency Department Congestion, Anjee Gorkhali

Theses and Dissertations in Business Administration

Alleviating Emergency Department (ED) congestion results in shorter hospital stay which not only reduces the cost of medical procedure but also increase the hospital performance. Length of patient stay is used to determine the hospital performance. Organization Information Processing (OIPT) Theory is used to explain the impact of information access and availability on the information processing need and ability of a hospital. Technical devices such as RFID that works as “Auto Identification tags” is suggested to increase the information availability as well as the information processing capability of the hospitals. This study suggests that the OIPT needs to be further …

Novel Use Of Neural Networks To Identify And Detect Electrical Infrastructure Performance, Evan Pierre Savaria

Computer Science Theses & Dissertations

Electrical grid maintenance and repairs are crucial services that keep America’s lights on. Electrical service providers make it their priority to uphold minimal interruptions to this service. Electricity is essential for modern technology within the home, such as cooking, refrigeration, and hot water. Organizations, such as schools, hospitals, and military bases, cannot properly function or operate without power. When analyzing the current electrical infrastructure, it is evident that considerable components of the power grid are aging and in need of replacement. Additionally, threats and damage continue to occur. These damages occur not only due to simple, single power line failure …

Developing Algorithms To Detect Incidents On Freeways From Loop Detector And Vehicle Re-Identification Data, Biraj Adhikari

Civil & Environmental Engineering Theses & Dissertations

A new approach for testing incident detection algorithms has been developed and is presented in this thesis. Two new algorithms were developed and tested taking California #7, which is the most widely used algorithm to date, and SVM (Support Vector Machine), which is considered one of the best performing classifiers, as the baseline for comparisons. Algorithm #B in this study uses data from Vehicle Re-Identification whereas the other three algorithms (California #7, SVM and Algorithm #A) use data from a double loop detector for detection of an incident. A microscopic traffic simulator is used for modeling three types of incident …

Success Factors Impacting Artificial Intelligence Adoption --- Perspective From The Telecom Industry In China, Hong Chen

Theses and Dissertations in Business Administration

As the core driving force of the new round of informatization development and the industrial revolution, the disruptive achievements of artificial intelligence (AI) are rapidly and comprehensively infiltrating into various fields of human activities. Although technologies and applications of AI have been widely studied, and factors that affect AI adoption are identified in existing literature, the impact of success factors on AI adoption remains unknown. Accordingly, the main study of this paper proposes a framework to explore the effects of success factors on AI adoption by integrating the technology, organization, and environment (TOE) framework and diffusion of innovation (DOI) theory. …

Lipid Biomarkers Of Bering And Chukchi Sea Euphausiids And Their Application To Diet History, Rachel L. Pleuthner

OES Theses and Dissertations

In the eastern Bering Sea, Thysanoessa raschii are the most abundant krill species and a keystone trophic member that serve as both an important grazer and link to upper level consumers. In this system krill experience large annual variation in food resources, especially during ice advance and retreat; multiple lipid classes are used to temper the effects of those fluctuations, as well as to fuel reproduction and growth. Two shipboard feeding experiments that occurred during late spring and early summer of 2010, respectively, monitored the lipid retention in adult T. raschii and examined the fluctuation of specific lipid biomarkers under …

A Dual Nanostructured Approach To Sers Amenable To Large-Scale Production, Kory Brian Castro

Chemistry & Biochemistry Theses & Dissertations

A SERS device was made using a dual-nanostructured surface comprised of silver nanoparticle and silver nanowires. The ability of each nanostructure to produce a uniform surface was characterized and the surface-enhanced Raman scattering (SERS) response of the resulting surfaces were examined using the reporter molecule 4-aminothiolphenol (ATP) and a 638 nm excitation laser.

A synthetic method was developed to produce silver nanowires with lengths of ~20 μm and diameters of ~100 nm with a narrow size distribution. The method utilized a simple, one-pot synthesis that is amenable to large-scale production. A selective precipitation method was used to the isolate the …

Latent Choice Models To Account For Misclassification Errors In Discrete Transportation Data, Lacramioara Elena Balan

Civil & Environmental Engineering Theses & Dissertations

One of the most fundamental tasks when it comes to analyzing data using statistical methods is to understand the relationship between the explanatory variables and the outcome. Misclassification of explanatory variables is a common risk when using statistical modeling techniques. In this dissertation, we define ‘misclassification,’ as a response that is reported or recorded in the wrong category; for example, a variable is registered as a one when it should have the value zero. Misclassification can easily happen in any data; for example, in an interview setting where the respondent misunderstands the question or the interviewer checks the wrong box. …