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Full-Text Articles in Physical Sciences and Mathematics

Adaptation Of A Low-Cost Hyperpolarization Technique For Use With Single-Sided Nmr, Ruth A. Beaver May 2020

Adaptation Of A Low-Cost Hyperpolarization Technique For Use With Single-Sided Nmr, Ruth A. Beaver

Undergraduate Honors Theses

Nuclear magnetic resonance (NMR) suffers from inherent signal problems due to low levels of nuclear polarization at room temperature. These problems are especially prevalent in single-sided NMR, which allows for a more flexible measurement geometry and simpler, cheaper instrumentation than traditional NMR. Hyperpolarization techniques can remedy this by providing artificially high levels of polarization for a single measurement. Signal Amplification By Reversible Exchange (SABRE) hyperpolarization is particularly advantageous, since it can be produced quickly using relatively cheap and simple instrumentation. While SABRE hyperpolarization has been successfully demonstrated with traditional NMR, it has not yet been adapted for single-sided NMR. Here ...


Non-Linear Modifications Of Black-Scholes Pricing Model With Diminishing Marginal Transaction Cost, Kaidi Wang May 2020

Non-Linear Modifications Of Black-Scholes Pricing Model With Diminishing Marginal Transaction Cost, Kaidi Wang

Undergraduate Honors Theses

In the field of quantitative financial analysis, the Black-Scholes Model has exerted significant influence on the booming of options trading strategies. Publishing in their Nobel Prize Work in 1973, the model was generated by Black and Scholes. Using Ito’s Lemma and portfolio management methodology, they employed partial differential equation to provide a theoretical estimate of the price of European-style options.

This paper is interested in deriving non-linear modifications of the Black-Scholes model with diminishing marginal transaction cost.


Conservation Of Orbital Angular Momentum In Degenerate Four-Wave Mixing Via Rubidium Vapor, Kangning Yang May 2020

Conservation Of Orbital Angular Momentum In Degenerate Four-Wave Mixing Via Rubidium Vapor, Kangning Yang

Undergraduate Honors Theses

We present an experimental platform which can generate quantum-correlated beams with Orbital Angular Momentum (OAM) via degenerate Four-Wave Mixing (FWM) in Rubidium vapor. We further investigated the conservation of OAM before and after FWM by performing LG mode decomposition using interferometer. To compare our experimental result with theoretical prediction, we simulated a simplified version of our set up. Moreover, we used this toy model to study the conservation of radial and angular intensity profile through changing parameters limited by our set up. In general, we found that FWM preserves most information consisted in OAM, but has a rather loose control ...


Determination Of Thermodynamic Properties Of Non-Protein Amino Acids And Characterization Of Multimers Of Carbamazepine, Gwendylan Turner May 2020

Determination Of Thermodynamic Properties Of Non-Protein Amino Acids And Characterization Of Multimers Of Carbamazepine, Gwendylan Turner

Undergraduate Honors Theses

This study has two seemingly unrelated parts that come together remarkably in displaying the comprehensive interplay between chemical structure and properties as well as the variety of analytical applications of mass spectrometry.

The first part of this study describes the determination of thermodynamic properties of several non-protein amino acids using the extended kinetic method. This is a continuation of work started in the Poutsma lab in Spring of 2017. The non-protein amino acids (NPA) studied here hold notable relevance in their unique ability to be mis-incorporated into peptide chains, as shown by the Hartman group at Virginia Commonwealth University.[1 ...


Four-Wave Mixing With Orbital Angular Momentum Transfer, Hana Warner May 2020

Four-Wave Mixing With Orbital Angular Momentum Transfer, Hana Warner

Undergraduate Honors Theses

We explore the conservation of orbital angular momentum (OAM) in the four-wave mixing (FWM) process in hot rubidium vapor. Since most modern communication systems send data in pulses corresponding to bits, we can use OAM to encode more information in each pulse by assigning structure to each signal. Furthermore, because FWM can be used to generate entangled photon pairs, we can use this process to bring enhanced signal security. We experimentally studied FWM with a wide range of Laguerre-Gaussian modes and their superpositions and observed OAM transfer from the probe field to a generated Stokes field. By studying the output ...


Gait Characterization Using Computer Vision Video Analysis, Martha T. Gizaw May 2020

Gait Characterization Using Computer Vision Video Analysis, Martha T. Gizaw

Undergraduate Honors Theses

The World Health Organization reports that falls are the second-leading cause of accidental death among senior adults around the world. Currently, a research team at William & Mary’s Department of Kinesiology & Health Sciences attempts to recognize and correct aging-related factors that can result in falling. To meet this goal, the members of that team videotape walking tests to examine individual gait parameters of older subjects. However, they undergo a slow, laborious process of analyzing video frame by video frame to obtain such parameters. This project uses computer vision software to reconstruct walking models from residents of an independent living retirement ...


Unmasking A Terrane Triple Point In Central Virginia, Ryan Walter May 2020

Unmasking A Terrane Triple Point In Central Virginia, Ryan Walter

Undergraduate Honors Theses

The central and southern Appalachian Piedmont contains terranes with both Laurentian and Gondwanan affinities that were amalgamated during a series of Paleozoic orogenies. In the southwestern Virginia Piedmont, the Smith River Allochthon (SRA) is interpreted as a peri-Gondwanan or distal Laurentian regional scale thrust sheet of metaclastic and meta-igneous rocks. The SRA was first identified in southern Virginia, and regional-scale maps extend the SRA northeast into the central Virginia Piedmont along the boundary between the Blue Ridge (BR) and western Piedmont (WP). In southern Virginia, the Bowens Creek fault separates the BR from the WP, and regional maps project this ...


Studies In Seop Hyperpolarized 3he: Measuring Ko And The Spatial Dependence Of Alkali Polarization, Michael Cairo May 2020

Studies In Seop Hyperpolarized 3he: Measuring Ko And The Spatial Dependence Of Alkali Polarization, Michael Cairo

Undergraduate Honors Theses

3He is an isotope of helium whose nucleus is composed of two protons and one neutron. The proportion of atoms whose spins are pointed along the same direction in a volume of 3He gas is known as the polarization. This study entails two experiments in the field of 3He polarimetry concerned with measuring the polarization of a 3He cell and reducing the uncertainty associated with it. 3He cells are full of gaseous 3He, along with alkali metal vapors, K and Rb in our case. The polarization of a 3He cell can be measured ...


Computational Simulations Of Temperature-Dependent Dynamics In Type Ii Superconductors Using A Material Specific Formulation Of Ginzburg Landau Theory, Aiden Harbick May 2020

Computational Simulations Of Temperature-Dependent Dynamics In Type Ii Superconductors Using A Material Specific Formulation Of Ginzburg Landau Theory, Aiden Harbick

Undergraduate Honors Theses

Superconducting Radio Frequency (SRF) cavities play a fundamental role in particle accelerators. Efficient operation depends on expelling magnetic flux from the cavity, and any residual flux that remains trapped after cooling below the critical temperature can have a significant impact on performance. Experimental evidence suggests that material defects as well as cooling protocols can have a strong impact on subsequent performance. To better understand these phenomena, we use time-dependent Ginzburg-Landau theory implemented as finite-element simulations. We adapt the theory to allow spatial variation of material-specific parameters along with realistic temperature dependencies. We report on numerical experiments for different configurations of ...


Development Of Wearable Sensors For Gait Analysis, Jorden Smyth May 2020

Development Of Wearable Sensors For Gait Analysis, Jorden Smyth

Undergraduate Honors Theses

In an ongoing experiment being conducted at The Williamsburg Landing by The Center for Balance and Aging Studies (CBAS), gait analysis is being performed on senior citizens in order to identify gait characteristics that are predictive of an increased likelihood to fall. This thesis describes the design and analysis of wearable sensors meant to assist the Williamsburg Landing study by increasing the efficiency and breadth of data collection. These sensors collect distance data from the foot to the ground over the course of multiple steps and return an approximation of the average step cycle for the subject. From my analysis ...


Stage-Structured Blue Crab Population Model With Fishing, Predation And Cannibalism, Fangming Xu May 2020

Stage-Structured Blue Crab Population Model With Fishing, Predation And Cannibalism, Fangming Xu

Undergraduate Honors Theses

Blue crab is a species of crab commonly found in the waters of the western Atlantic Ocean. It is one of the most important shellfish in the Chesapeake Bay. The blue crab fishing industry has a notable impact on the local economy, and blue crabs form a key link in the Chesapeake Bay food web. Between the mid-1990s and 2004, the blue crab population dropped by two thirds. Factors such as habitat loss, harvest pressure and climate change may have contributed to the decline. However, there hasn’t been enough research on the long term dynamic equilibrium, making it difficult ...


Dynamics Of Sensory Integration Of Olfactory And Mechanical Stimuli Within The Response Patterns Of Moth Antennal Lobe Neurons, Harrison Tuckman May 2020

Dynamics Of Sensory Integration Of Olfactory And Mechanical Stimuli Within The Response Patterns Of Moth Antennal Lobe Neurons, Harrison Tuckman

Undergraduate Honors Theses

Odors emanating from a biologically relevant source are rapidly embedded within a windy, turbulent medium that folds and spins filaments into fragmented strands of varying sizes. Environmental odor plumes therefore exhibit complex spatiotemporal dynamics, and rarely yield an easily discernible concentration gradient marking an unambiguous trail to an odor source. Thus, sensory integration of chemical input, encoding odor identity or concentration, and mechanosensory input, encoding wind speed, is a critical task that animals face in resolving the complex dynamics of odor plumes and tracking an odor source. In insects, who employ olfactory navigation as their primary means of foraging for ...


Learning & Planning For Self-Driving Ride-Hailing Fleets, Jack Morris May 2020

Learning & Planning For Self-Driving Ride-Hailing Fleets, Jack Morris

Undergraduate Honors Theses

Through simulation, we demonstrate that incorporation of self-driving vehicles into ride-hailing fleets can greatly improve urban mobility. After modeling existing driver-rider matching algorithms including Uber’s Batched Matching and Didi Chuxing’s Learning and Planning approach, we develop a novel algorithm adapting the latter to a fleet of Autos – self-driving ride-hailing vehicles – and Garages – specialized hubs for storage and refueling. By compiling driver-rider matching, idling, storage, refueling, and redistribution decisions in one unifying framework, we enable a system-wide optimization approach for self-driving ride-hailing previously unseen in the literature. In contrast with existing literature that labeled driverless taxis as economically infeasible ...


Modeling Movement: A Machine-Learning Approach To Track Migration Routes After Displacement, Ethan Harrison May 2020

Modeling Movement: A Machine-Learning Approach To Track Migration Routes After Displacement, Ethan Harrison

Undergraduate Honors Theses

Over the past decade, the number of individuals internally displaced by conflict (IDPs) has reached unprecedented levels. Humanitarian actors and first-responders face persistent information gaps in meeting the needs of these populations. Specifically, they face challenges in understanding where and how IDPs move after they are displaced, which is necessary to locate them in conflict-affected situations and provide them with life-saving assistance. In this paper, I propose a framework, using established machine-learning methods, to forecast the migration routes of these displaced populations (Chapter 1). In a case study of displacement in Yemen, my models predict 80% of IDPs' migration routes ...


Chemical Transformation Of Biomass Burning Organic Aerosols Due To Photolytic Aging, Hongmin Yu May 2020

Chemical Transformation Of Biomass Burning Organic Aerosols Due To Photolytic Aging, Hongmin Yu

Undergraduate Honors Theses

Biomass burning organic aerosol (BBOA), organic aerosol that derived from burning of biomass fuels, has been a major research focus because of its special role in the global budget of atmospheric chemistry and radiative forcing. Due to its chemical complexity, there are gaps in our knowledge about the chemical aging processes of BBOA in the atmosphere. Since many photochemical aging experiments on BBOA are usually conducted for only a few hours, less is known about the photo-aging pathways of the system over an extended timescale. This study presents the analyses of three BBOA filter samples derived from three types of ...


Development And Upgrade Of A Laser Cooling And Trapping System Of Ultracold Potassium Atoms, Bennett Atwater May 2020

Development And Upgrade Of A Laser Cooling And Trapping System Of Ultracold Potassium Atoms, Bennett Atwater

Undergraduate Honors Theses

This thesis describes work to improve the apparatus that cools and loads potassium atoms onto the atom chip. This work consists of two main thrusts: a laser trap translator to help cool and load atoms onto the atom chip and a temperature stabilization system for the lasers that are used to laser cool potassium atoms. The current iteration of the beam translator has the ability to vertically translate a beam ±4.5 mm relative to its incident height. The translator has been shown to not alter the spatial profile of the beam through interference or obstruction. The translator’s rotation ...


Studying And Correcting For Helicity-Correlated False Asymmetries In The Prex Ii And Crex Experiments, Carrington Metts May 2020

Studying And Correcting For Helicity-Correlated False Asymmetries In The Prex Ii And Crex Experiments, Carrington Metts

Undergraduate Honors Theses

The goal of the PREx II and CREx experiments are to determine the size of the neutron distribution in 208Pb and 48Ca, respectively. Because these isotopes have a large discrepancy in between the number of neutrons and protons, theoretical models predict that some of the neutrons will arrange themselves in a “skin” on the nucleus’s surface. Prior results from the PREx I experiment confirmed the existence of the neutron skin in 208Pb. All of the mentioned experiments employ the technique of parity-violating electron scattering. Electron-nucleus weak interactions are dominated by electron-neutron scattering, which is an order ...


Analysis Of Modelling Deficiencies That Contributed To The High Unanticipated Loan Losses Incurred During The Housing Price Collapse Of The Great Recession, Jennifer Shulman May 2020

Analysis Of Modelling Deficiencies That Contributed To The High Unanticipated Loan Losses Incurred During The Housing Price Collapse Of The Great Recession, Jennifer Shulman

Undergraduate Honors Theses

In this paper the data, modelling and the environmental factors that contributed to the collapse of the US housing market and the high mortgage loan losses during the Great Recession are explored. Deficiencies in data and modelling are discussed with an emphasis on the deficiencies in the mathematical modeling that failed to predict the high level of risk associated with mortgage originations in the mid-2000's. It is suggested that the lack of effective modelling significantly contributed to banks offering aggressive origination guidelines and that this was a major contributing factor that led up to the housing price collapse in ...


Vims 2019 York River Estuary Data In Support Of: Improved Penetrometer Performance In Stratified Sediment For Cost-Effective Characterization, Monitoring And Management Of Submerged Munitions Sites (Serdp Project: Mr18-1233), Grace M. Massey, Cristin L. Wright, Carl T. Friedrichs May 2020

Vims 2019 York River Estuary Data In Support Of: Improved Penetrometer Performance In Stratified Sediment For Cost-Effective Characterization, Monitoring And Management Of Submerged Munitions Sites (Serdp Project: Mr18-1233), Grace M. Massey, Cristin L. Wright, Carl T. Friedrichs

Data

This work complements the efforts by the Virginia Tech Department of Civil & Environmental Engineering in SERDP MR18-1233, as described in the project’s final report (Stark et al, 2020) and in the Master’s thesis by Dennis Kiptoo (Kiptoo, 2020). One of the objectives of the project was to improve calibration of the Bluedrop free fall penetrometer (FFP) with high resolution sampling of a variety of sediment types. To accomplish this, a series of 9 stations over 12 cruises were visited along the York River, an estuary in the Virginia portion of the Chesapeake Bay, and in the Pamunkey River ...


Vims 2019 Potomac River Estuary Data In Support Of: Improved Penetrometer Performance In Stratified Sediment For Cost-Effective Characterization, Monitoring And Management Of Submerged Munitions Sites (Serdp Project: Mr18-1233), Grace M. Massey, Cristin L. Wright, Carl T. Friedrichs May 2020

Vims 2019 Potomac River Estuary Data In Support Of: Improved Penetrometer Performance In Stratified Sediment For Cost-Effective Characterization, Monitoring And Management Of Submerged Munitions Sites (Serdp Project: Mr18-1233), Grace M. Massey, Cristin L. Wright, Carl T. Friedrichs

Data

This work complements the efforts by the Virginia Tech Department of Civil & Environmental Engineering in SERDP MR18-1233, as described in the project’s final report (Stark et al, 2020) and in the Master’s thesis by Dennis Kiptoo (Kiptoo, 2020). Previous work on this project, conducted in the York River during 2018-2918 worked to improve calibration of the Bluedrop free fall penetrometer (FFP) with high resolution sampling of a variety of sediment types (Massey et al, 2020a). Calibration methods developed (Kiptoo, 2020) were used to rapidly identify different sediment types from a grid of 59 Bluedrop PPF stations sampled on ...


Data Acquisition And Analysis For Helicity-Correlated Asymmetries In Prex-Ii, Quinn Campagna Apr 2020

Data Acquisition And Analysis For Helicity-Correlated Asymmetries In Prex-Ii, Quinn Campagna

Undergraduate Honors Theses

The goal of PREx-II is to measure the radius of the neutron distribution in the nucleus of 208Pb to a precision of +/-1%, the original proposed goal of PREx-I. This is done by scattering polarized electrons off of a lead target, taking advantage of the parity-violating nature of the weak interaction. The difference in the scattering cross section for each helicity state allows us to extract the neutron radius of the nucleus. There can, however, be helicity-correlated beam asymmetries that are not related to the weak interaction. In order to extract these errors, we periodically modulate the beam energy ...


Rmse-Minimizing Confidence Intervals For The Binomial Parameter, Kexin Feng Apr 2020

Rmse-Minimizing Confidence Intervals For The Binomial Parameter, Kexin Feng

Undergraduate Honors Theses

Let X1, X2, . . . , Xn be independent and identically distributed Bernoulli(p) random variables with unknown parameter p satisfying 0 < p < 1. Let X = Pn i=1 Xi be the number of successes in the n mutually independent Bernoulli trials. The maximum likelihood estimator of p is ˆp = X/n. For fixed n and α, there are n + 1 distinct 100(1 − α)% confidence intervals associated with X = 0, 1, 2, . . . , n. Currently there is no known exact confidence interval for p. Our goal is to construct the confidence interval for p whose actual coverage is closest to the stated coverage, using the root mean squared error, RMSE, to measure the difference between the actual coverage and the stated coverage. The approximate confidence interval for p developed here minimizes the RMSE for a sample size n and a significance level α.


Atomic Magnetometry For The Detection Of Cardio-Magnetic Fields, Alexander Fay Apr 2020

Atomic Magnetometry For The Detection Of Cardio-Magnetic Fields, Alexander Fay

Undergraduate Honors Theses

We demonstrate a method of measuring small constant gradients on top of a large constant background magnetic field using Electromagnetically Induced Transparency (EIT). The Earth provides a constant magnetic field of 25-50 μT, and as such, measuring much smaller magnetic fields as well as smaller gradients presents a challenge often requiring special shielding. We show that by making use of common mode noise subtraction from a dual rail setup, our measurement is insensitive to these large fields, and in theory our method does not require shielding. Our dual rail setup allows us to measure small magnetic field gradients by utilizing ...


Vulnerability And Resilience Of Tidal Marshes Along An Estuarine Salinity Gradient, Megan Gillen Apr 2020

Vulnerability And Resilience Of Tidal Marshes Along An Estuarine Salinity Gradient, Megan Gillen

Undergraduate Honors Theses

Tidal marshes are coastal landforms that provide invaluable ecosystem services but are vulnerable to sea-level rise and saltwater intrusion. Processes at the marsh seaward and landward boundaries control their size and survival. At the seaward boundary, a primary cause of marsh loss is erosion. However, it is currently unknown how increased saltwater intrusion will affect erosion rates. At the landward boundary, marshes migrate into adjacent terrestrial uplands which undergo stresses from rising sea-level, expanding wetland lateral extent. This thesis assesses marsh vulnerability to saltwater intrusion by quantifying marsh erodibility and migration potential along a salinity gradient in the York River ...


Development Of Convolutional Neural Nets For Κ/Π Differentiation At The Gluex Experiment, Matthew Mceneaney Apr 2020

Development Of Convolutional Neural Nets For Κ/Π Differentiation At The Gluex Experiment, Matthew Mceneaney

Undergraduate Honors Theses

Lattice Quantum Chromodynamics (QCD) calculations predict a whole spectrum of exotic hybrid mesons thought to arise from gluonic excitation between a quark and antiquark. A systematic survey of strange and non-strange decay modes would be necessary to confirm this, and in particular studying decays to kaonic final states could confirm initial lattice QCD predictions. The GlueX experiment at Jefferson Lab studies the non-perturbative regime of the strong interaction and searches for hybrid mesons through light-quark meson spectroscopy; thus, kaon identification is critical for the GlueX experiment. Currently, the GlueX DIRC (Detection of Internally Reflected Cherenkov light) detectors provide clear kaon ...


Nonnegative Matrix Factorization Problem, Junda An Apr 2020

Nonnegative Matrix Factorization Problem, Junda An

Undergraduate Honors Theses

The Nonnegative Matrix Factorization (NMF) problem has been widely used to analyze high-dimensional nonnegative data and extract important features. In this paper, I review major concepts regarding NMF, some NMF algorithms and related problems including initialization strategies and near separable NMF. Finally I will implement algorithms on generated and real data to compare their performances.


Massive Pollutants Released To Galveston Bay During Hurricane Harvey: Understanding Their Retention And Pathway Using Lagrangian Numerical Simulations, Jiabi Du, Kyeong Park, Xin Yu, Yinglong J. Zhang, Fei Ye Feb 2020

Massive Pollutants Released To Galveston Bay During Hurricane Harvey: Understanding Their Retention And Pathway Using Lagrangian Numerical Simulations, Jiabi Du, Kyeong Park, Xin Yu, Yinglong J. Zhang, Fei Ye

VIMS Articles

Increasing frequency of extreme precipitation events under the future warming climate makes the storm-related pollutant release more and more threatening to coastal ecosystems. Hurricane Harvey, a 1000-year extreme precipitation event, caused massive pollutant release from the Houston metropolitan area to the adjacent Galveston Bay. 0.57 × 106 tons of raw sewage and 22,000 barrels of oil, refined fuels and chemicals were reportly released during Harvey, which would likely deteriorate the water quality and damage the coastal ecosystem. Using a Lagrangian particle-tracking method coupled with a validated 3D hydrodynamic model, we examined the retention, pathway, and fate of the ...


Surface Water Nitrogen Attenuation From The Accomack County, Va Southern Landfill Groundwater Discharge, Richard A. Snyder, Paige G. Ross Feb 2020

Surface Water Nitrogen Attenuation From The Accomack County, Va Southern Landfill Groundwater Discharge, Richard A. Snyder, Paige G. Ross

Reports

Previous sampling of the stream crossing Bobtown Road (Rt 178) near the intersection of Hollies Church Road (Rt. 620), had indicated high levels of nitrogen in the stream flow (Snyder and Ross, 2019a). The proximity of the retired Accomack County Landfill upstream of the site triggered a higher resolution sampling of the stream in an attempt to isolate a source of the nitrogen loading (Snyder and Ross, 2019b). Accomack County has requested repeated sampling of this stream segment to monitor nutrient attenuation trends from the site, and stations were established for that purpose. This is the first report of that ...


Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2019 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee Jan 2020

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2019 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twenty-second year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2019, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on two fishery-independent monitoring programs using anchor gillnets in the Rappahannock River (year 2) and the Chickahominy River (year 5; a major tributary of the James River), to determine relative abundance and stock structure for the adult spawning run of river herring ...


Water Quality In Accomack County Freshwater Streams, Richard A. Snyder, Paige G. Ross Jan 2020

Water Quality In Accomack County Freshwater Streams, Richard A. Snyder, Paige G. Ross

Reports

Expansion of poultry house operations and use of litter as a soil amendment in Accomack County Virginia has raised concerns for water quality impacts both seaside and bayside of the Eastern Shore of Virginia (ESVA). This ongoing investigation is examining freshwater stream water quality in Accomack Virginia to identify water quality impairments from poultry operation storm water runoff. Sampling in 2019 followed two inch rainfall events covering 83 streams at road crossings in southern and northern Accomack County. Estimates of land cover in the drainages for these streams were used to determine correlations between stream water nutrient levels and the ...