Physical Sciences and Mathematics Commons^™

Generation Of Large-Volume Diffuse Plasma By An External Ionization Wave From A Single-Electrode Plasma Jet, Seyed Hamid Razavi Barzoki

Electrical & Computer Engineering Theses & Dissertations

A non-thermal transient diffuse plasma can be generated remotely in a nonconductive reduced pressure chamber by an external guided fast ionization wave (FIW). We found that an atmospheric-pressure low-temperature plasma jet (APPJ) can be a source of FIW which transfers an enhanced electric field at the wave front across a reduced pressure Pyrex glass chamber with no electrical connection to the chamber. Here, we studied the formation and propagation of the APPJ plasma, the interaction of atmospheric-pressure guided FIW with a dielectric surface which forms the wall of the reduced-pressure system, and the formation and propagation of the reduce-pressure FIW …

Deep Learning For Segmentation Of 3d Cryo-Em Images, Devin Reid Haslam

Computer Science Theses & Dissertations

Cryo-electron microscopy (cryo-EM) is an emerging biophysical technique for structural determination of protein complexes. However, accurate detection of secondary structures is still challenging when cryo-EM density maps are at medium resolutions (5-10 Å). Most existing methods are image processing methods that do not fully utilize available images in the cryo-EM database. In this paper, we present a deep learning approach to segment secondary structure elements as helices and β-sheets from medium- resolution density maps. The proposed 3D convolutional neural network is shown to detect secondary structure locations with an F1 score between 0.79 and 0.88 for six simulated test cases. …

Potential Interaction Analysis Of Offshore Wind Energy Areas And Breeding Avian Species On The Us Mid-Atlantic Coast, Jeri Lynn Wisman

Biological Sciences Theses & Dissertations

Due to increasing US interest in developing wind energy sites in offshore waters, we synthesized existing data on colonial breeding seabird populations with the potential risk of interacting with lease areas in the mid-Atlantic. Previous efforts by BOEM and NOAA have predicted avian density using at-sea survey data; we seek to complement this work by focusing specifically on birds during the critical and energetically demanding breeding life history stage. We combined colony size and location for each species along the mid-Atlantic coast with buffers around the colonies that correlate with the species’ foraging range. We integrated population size, vulnerability to …

Plastics And Microplastics As Vectors For Bacteria And Human Pathogens, Amanda Lee Laverty

OES Theses and Dissertations

Since plastics degrade very slowly, they remain in the environment on much longer timescales than most natural substrates and can thus provide a novel habitat for colonization by bacterial communities. The full spectrum of relationships between plastics and bacteria, however, is little understood. The objective of this study was to examine marine plastic pollution as a substrate for bacteria, with particular focus on Vibrio spp., including the human pathogens, Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus.

Colonization experiments were set up in a tributary of the lower Chesapeake Bay to follow Vibrio spp. colonization and …

Analysis Of Bulk Power System Resilience Using Vulnerability Graph, Md Ariful Haque

Computational Modeling & Simulation Engineering Theses & Dissertations

Critical infrastructure such as a Bulk Power System (BPS) should have some quantifiable measure of resiliency and definite rule-sets to achieve a certain resilience value. Industrial Control System (ICS) and Supervisory Control and Data Acquisition (SCADA) networks are integral parts of BPS. BPS or ICS are themselves not vulnerable because of their proprietary technology, but when the control network and the corporate network need to have communications for performance measurements and reporting, the ICS or BPS become vulnerable to cyber-attacks. Thus, a systematic way of quantifying resiliency and identifying crucial nodes in the network is critical for addressing the cyber …

New Methods To Improve Protein Structure Modeling, Maha Abdelrasoul

Computer Science Theses & Dissertations

Proteins are considered the central compound necessary for life, as they play a crucial role in governing several life processes by performing the most essential biological and chemical functions in every living cell. Understanding protein structures and functions will lead to a significant advance in life science and biology. Such knowledge is vital for various fields such as drug development and synthetic biofuels production.

Most proteins have definite shapes that they fold into, which are the most stable state they can adopt. Due to the fact that the protein structure information provides important insight into its functions, many research efforts …

The Importance Of Keeping The Big Ones: Harvest Slot Limits And Marine Protected Areas For The Management Of The Caribbean Spiny Lobster, Gayathiri Gnanalingam

Biological Sciences Theses & Dissertations

Fishing typically removes the oldest and/or largest individuals from populations undermining stability and reproductive success. Traditional fisheries management tools fail to protect these oldest and/or largest individuals, but two less conventional tools: marine protected areas (MPAs), and harvest slot limits have the potential to do so. Here I tested the possible use of these tools for the Caribbean spiny lobster, Panulirus argus, an iconic and economically valued species. After decades of intense fishing, the largest lobsters have largely been wiped out. The loss of the largest lobsters is significant as large lobsters have considerably greater reproductive potential than their …

Advances In Amino Acid Analysis For Marine Related Matrices And Its Application To Coastal Shelf Settings In The Canadian Arctic, Rachel M. Mcmahon

OES Theses and Dissertations

Amino acids comprise up to 50% of organic matter in cellular material and are a major fraction of oceanic organic carbon. Amino acids are also considered highly labile during organic matter recycling, making them useful proxies for organic carbon cycling. Nevertheless, analysis of individual amino acids has been burdened by lengthy derivatization and complex analysis since the 1950s. In this thesis, I describe the modification of advanced analytical techniques, developed in the biomedical field, for analysis of marine matrices which allow the determination of at least 40 amino acids without the need for lengthy sample preparation and derivatization, twice the …

Novel Technique For Gait Analysis Using Two Waist Mounted Gyroscopes, Ahmed Nasr

Computer Science Theses & Dissertations

Analysis of the human gait is used in many applications such as medicine, sports, and person identification. Several research studies focused on the use of MEMS inertial sensors for gait analysis and showed promising results. The miniaturization of these sensors and their wearability allowed the analysis of gait on a long term outside of the laboratory environment which can reveal more information about the person and introduced the use of gait analysis in new applications such as indoor localization.

Step detection and step length estimation are two basic and important gait analysis tasks. In fact, step detection is a prerequisite …

Fabrication Of An Apparatus For All-Optical Production Of Metastable Krypton, Lindsay M. Thornton

Physics Theses & Dissertations

Atom Trap Trace Analysis (ATTA) has made radiokrypton dating of polar ice and groundwater samples a possibility for scientists all over the world, allowing them to date samples further back in time and more accurately than other methods. However, this technique is hampered by the 36-hour cleaning process required for production of metastable-state krypton atoms via a radio-frequency driven plasma. Production of metastable krypton all-optically would dramatically increase the rate at which samples could be measured. Attempts to build an apparatus that could accomplish this have been done in the past but were lacking in aordability and practicality for widespread …

The Effect Of Soxhlet Extraction And Synthesis Temperature On Properties Of Polyaniline, Samuel Watson Stahl

Chemistry & Biochemistry Theses & Dissertations

Polyaniline was synthesized by the chemical oxidation of aniline in an HCl solution by ammonium persulfate. The temperature of the synthesis was varied to increase the molecular weight of the polymer from 37,600 Da to 52,400 Da. Soxhlet extraction using methanol as the primary solvent was performed on half the sample in order to further increase the average molecular weight by approximately 3150 Da and decrease the polydispersity index by 0.8. Films were cast from 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU) and N-methyl-2-pyrrolidone (NMP) and then doped with trifluoromethanesulfonic acid.

The effect of the soxhlet extraction and synthesis temperature on the polymer’s properties …

Non-Destructive Evaluation For Composite Material, Desalegn Temesgen Delelegn

Electrical & Computer Engineering Theses & Dissertations

The Nondestructive Evaluation Sciences Branch (NESB) at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) has conducted impact damage experiments over the past few years with the goal of understanding structural defects in composite materials. The Data Science Team within the NASA LaRC Office of the Chief Information Officer (OCIO) has been working with the Non-Destructive Evaluation (NDE) subject matter experts (SMEs), Dr. Cheryl Rose, from the Structural Mechanics & Concepts Branch and Dr. William Winfree, from the Research Directorate, to develop computer vision solutions using digital image processing and machine learning techniques that can help identify …

Characterizing The Activity Of Antimicrobial Peptides Against The Pathogenic Bacterium Clostridium Difficile In An Anaerobic Environment, Adenrele Mojeed Oludiran

Chemistry & Biochemistry Theses & Dissertations

Clostridium difficile is an anaerobic Gram-positive pathogen with high treatment costs and mortality and very high antibiotic tolerance. Antimicrobial host-defense peptides (HDPs) produced naturally by animal immune systems are promising candidates to develop novel therapies for bacterial infection because they cause oxidative stress that damages multiple targets in bacterial cells, so it is difficult for bacteria to evolve resistance to these attacks.

Piscidins, fish-derived HDPs that can also form complexes with copper (Cu) to enhance their activities, are very active against multiple bacterial species in an aerobic environment. We examined their activity against C. difficile and other species in an …

Identifying Marine Key Biodiversity Areas In The Greater Caribbean Region, Michael S. Harvey

Biological Sciences Theses & Dissertations

Anthropocene biodiversity extinction rates are increasing, suggesting a possible sixth global mass extinction event. Biological conservation planners are consequently seeking ways to more effectively protect species at national, regional and global scales. In 2010, the Convention on Biological Diversity (CBD) issued a number of conservation goals (Aichi Targets), including the establishment of protected areas (PA) in terrestrial, freshwater and marine areas of eminent conservation concern by 2020 to reduce and eventually eliminate species’ extinctions, as well as preserve hotspots of biodiversity and dynamic ecosystems. While well-established, adequately enforced PAs increase the likelihood of preserving species and habitats most at risk …

Identification And Optimal Linear Tracking Control Of Odu Autonomous Surface Vehicle, Nadeem Khan

Mechanical & Aerospace Engineering Theses & Dissertations

Autonomous surface vehicles (ASVs) are being used for diverse applications of civilian and military importance such as: military reconnaissance, sea patrol, bathymetry, environmental monitoring, and oceanographic research. Currently, these unmanned tasks can accurately be accomplished by ASVs due to recent advancements in computing, sensing, and actuating systems. For this reason, researchers around the world have been taking interest in ASVs for the last decade. Due to the ever-changing surface of water and stochastic disturbances such as wind and tidal currents that greatly affect the path-following ability of ASVs, identification of an accurate model of inherently nonlinear and stochastic ASV system …

Odu, City Of Norfolk To Host Neighbors Building Neighborhoods Conference June 23, Noell Saunders

News Items

No abstract provided.

Odu, Mit Solve And Rise Co-Host Workshop For Local Entrepreneurs Focused On Coastal Resilience Solutions, Betsy Hnath

News Items

No abstract provided.

Ms Analysis Of A Dilution Series Of Bacteria: Phytoplankton To Improve Detection Of Low Abundance Bacterial Peptides, Emma Timmins-Schiffman, Molly P. Mikan, Ying Sonia Ting, H. Rodger Harvey, Brook L. Nunn

OES Faculty Publications

Assigning links between microbial activity and biogeochemical cycles in the ocean is a primary objective for ecologists and oceanographers. Bacteria represent a small ecosystem component by mass, but act as the nexus for both nutrient transformation and organic matter recycling. There are limited methods to explore the full suite of active bacterial proteins largely responsible for degradation. Mass spectrometry (MS)-based proteomics now has the potential to document bacterial physiology within these complex systems. Global proteome profiling using MS, known as data dependent acquisition (DDA), is limited by the stochastic nature of ion selection, decreasing the detection of low abundance peptides. …

Spectroscopic Constants And Line Positions For Tio Singlet States, Dror M. Bittner, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

consistent set of spectroscopic constants for the a¹Δ,d¹Σ⁺,b¹Π,c¹Φ, and f¹Δ states of ⁴⁸Ti¹⁶O has been determined from analysis of the b¹Π–a¹Δ,b¹Π–d¹Σ⁺,c¹Φ–a¹Δ, and f¹Δ–a¹Δ systems. Three Fourier transform emission spectra have been used for the analysis. New bands of the b¹Π–a¹Δ and c¹Φ–a¹Δ systems have been fitted. The first analysis of the c¹Φ–a¹Δ system using Fourier …

Integrating Statistical Methods In Engineering Technology Courses, Sanjeevi Chitikeshi, Jake Hildebrant, Otilia Popescu, Orlando M. Ayala, Vukica M. Jovanovic

Engineering Technology Faculty Publications

Statistical methods and procedures are very important in engineering applications. In most of the engineering fields electronic devices are used as sensing and controlling components. Lack of proper calibration of these devices and of performance analysis using different statistical methods may lead to erroneous measurements and results. In medical or manufacturing areas such errors in the experimental results could be catastrophic. Applying different statistical tests and procedures enhance the quality of engineering work. Traditionally, most engineering curricula have at least one required course in applied statistics in engineering, but that is not generally the case in engineering technology programs. Most …

Description And Mechanisms Of The Mid-Year Upwelling In The Southern Caribbean Sea From Remote Sensing And Local Data, Digna T. Rueda-Roa, Tal Ezer, Frank E. Muller-Karger

CCPO Publications

The southern Caribbean Sea experiences strong coastal upwelling between December and April due to the seasonal strengthening of the trade winds. A second upwelling was recently detected in the southeastern Caribbean during June-August, when local coastal wind intensities weaken. Using synoptic satellite measurements and in situ data, this mid-year upwelling was characterized in terms of surface and subsurface temperature structures, and its mechanisms were explored. The mid-year upwelling lasts 6-9 weeks with satellite sea surface temperature (SST) ~1-2°C warmer than the primary upwelling. Three possible upwelling mechanisms were analyzed: cross-shore Ekman transport (csET) due to alongshore winds, wind curl (Ekman …

Temporal And Spatiotemporal Investigation Of Tourist Attraction Visit Sentiment On Twitter, Jose J. Padilla, Hamdi Kavak, Christopher J. Lynch, Ross J. Gore, Saikou Y. Diallo

VMASC Publications

In this paper, we propose a sentiment-based approach to investigate the temporal and spatiotemporal effects on tourists' emotions when visiting a city's tourist destinations. Our approach consists of four steps: data collection and preprocessing from social media; visitor origin identification; visit sentiment identification; and temporal and spatiotemporal analysis. The temporal and spatiotemporal dimensions include day of the year, season of the year, day of the week, location sentiment progression, enjoyment measure, and multi-location sentiment progression. We apply this approach to the city of Chicago using over eight million tweets. Results show that seasonal weather, as well as special days and …

Electron- And Positron-Impact Ionization Of Inert Gases, R. I. Campeanu, H. R. J. Walters, Colm T. Whelan

Physics Faculty Publications

Triple-differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions which cannot be separately detected in an experiment with a single projectile. A comparison is presented between theory and the recent experiments of [Gavin, deLucio, and DuBois, Phys. Rev. A95, 062703 (2017)] for e^± and contrasted with the …

Developing A Framework To Identify Local Business And Government Vulnerability To Sea-Level Rise: A Case Study Of Coastal Virginia, Sarah L. Stafford, Alexander D. Renaud

May 11, 2018: Adaptation Policy

In this paper we develop methods for identifying local business and government vulnerabilities to sea-level rise and the natural hazards associated with it. Unlike the fairly large literature on measuring social vulnerability to natural hazards, there are very few papers that discuss methods for measuring local business or local government vulnerability even though businesses and governments are also differentially affected natural hazards. Our goal is to create measures that are easily replicable using readily available data and that are easy to explain to local planners, policy makers, and citizens. We implement our measures of local business and government vulnerability for …

Power Corrections To Tmd Factorization For Z-Boson Production, I. Balitsky, A. Tatasov

Physics Faculty Publications

A typical factorization formula for production of a particle with a small transverse momentum in hadron-hadron collisions is given by a convolution of two TMD parton densities with cross section of production of the final particle by the two partons. For practical applications at a given transverse momentum, though, one should estimate at what momenta the power corrections to the TMD factorization formula become essential. In this paper we calculate the first power corrections to TMD factorization formula for Z-boson production and Drell-Yan process in high-energy hadron-hadron collisions. At the leading order in N_c power corrections are expressed in …

Hard Exclusive Pion Electroproduction At Backward Angles With Clas, K. Park, M. Guidal, R. W. Gothe, B. Pire, G. Charles, C. E. Hyde, S E. Kuhn, J. Poudel, Y. Prok

Physics Faculty Publications

We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, ep → e'nπ⁺, above the resonance region at backward pion center-of-mass angles. The ϕ∗ π-dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs). These non-perturbative objects are defined as matrix elements of threequark-light-cone-operators and characterize partonic correlations with a particular emphasis on baryon charge distribution inside a nucleon.

Statistical Analysis And Comparison Of Optical Classification Of Atmospheric Aerosol Lidar Data, Kwasi Gyening Afrifa

Electrical & Computer Engineering Projects for D. Eng. Degree

This dissertation presents a new study for the analysis and classification of atmospheric aerosols in remote sensing LIDAR data. Information on particle size and associated properties are extracted from these remote sensing atmospheric data which are collected by a ground-based LIDAR system. This study first considers optical LIDAR parameter-based classification methods for clustering and classification of different types of harmful aerosol particles in the atmosphere. Since accurate methods for aerosol prediction behaviors are based upon observed data, computational approaches must overcome design limitations, and also consider appropriate calibration and estimation accuracy. Consequently, two statistical methods based on generalized linear models …

Light Availability And Phytoplankton Growth Beneath Arctic Sea Ice: Integrating Observations And Modeling, Victoria J. Hill, Bonnie Light, Michael Steele, Richard C. Zimmerman

OES Faculty Publications

Observations of the seasonal light field in the upper Arctic Ocean are critical to understanding the impacts of changing Arctic ice conditions on phytoplankton growth in the water column. Here we discuss data from a new sensor system, deployed in seasonal ice cover north‐east of Utqiaġvik, Alaska in March 2014. The system was designed to provide observations of light and phytoplankton biomass in the water column during the formation of surface melt ponds and the transition from ice to open water. Hourly observations of downwelling irradiance beneath the ice (at 2.9, 6.9, and 17.9 m depths) and phytoplankton biomass (at …

Characterization And Analysis Of Ultrathin Cigs Films And Solar Cells Deposited By 3-Stage Process, Grace Rajan, Krishna Aryal, Shankar Karki, Puruswottam Aryal, Robert W. Collins, Sylvain Marsillac

Electrical & Computer Engineering Faculty Publications

In view of the large-scale utilization of Cu(In,Ga)Se₂ (CIGS) solar cells for photovoltaic application, it is of interest not only to enhance the conversion efficiency but also to reduce the thickness of the CIGS absorber layer in order to reduce the cost and improve the solar cell manufacturing throughput. In situ and real-time spectroscopic ellipsometry (RTSE) has been used conjointly with ex situ characterizations to understand the properties of ultrathin CIGS films. This enables monitoring the growth process, analyzing the optical properties of the CIGS films during deposition, and extracting composition, film thickness, grain size, and surface roughness which …

Single-Stage, Venturi-Driven Desalination System, Brandon Proetto

Mechanical & Aerospace Engineering Theses & Dissertations

Water demand is increasing at a rapid pace due to population increase, industrial expansion, and agricultural development. The use of desalination technology to meet the high water demands has increased global online desalination capacity from 47 million m^3/d in 2007 to 92.5 million m^3/d as of June 2017 [49]. Membrane and thermal processes are the two mainstream desalination categories used worldwide for desalination plants. Reverse Osmosis (RO) is the most widely used membrane process and it has become the dominant technology for building desalination plants over recent decades. Thermal distillation, however, has become less and less competitive due to its …