Physical Sciences and Mathematics Commons^™

Two-Dimensional Ferroelectricity By Design, E. Y. Tsymbal

Evgeny Tsymbal Publications

No abstract provided.

Interfacial Crystal Hall Effect Reversible By Ferroelectric Polarization, 257. D.-F. Shao, J. Ding, G. Gurung, S.-H. Zhang, And E. Y. Tsymbal

Evgeny Tsymbal Publications

No abstract provided.

Modulation Of Spin-Orbit Torque From Srruo3 By Epitaxial-Strain-Induced Octahedral Rotation, J. Zhou, X. Shu, W. Lin, D. F. Shao, S. Chen, L. Liu, P. Yang, E. Y. Tsymbal, And J. Chen

Evgeny Tsymbal Publications

No abstract provided.

In-Plane Quasi-Single-Domain Batio3 Via Interfacial Symmetry Engineering, J. W. Lee, K. Eom, T. R. Paudel, B. Wang, H. Lu, H. X. Huyan, S. Lindemann, S. Ryu, H. Lee, T. H. Kim, Y. Yuan, J. A. Zorn, S. Lei, W. P. Gao, T. Tybell, V. Gopalan, X. Q. Pan, A. Gruverman, L. Q. Chen, E. Y. Tsymbal, And C. B. Eom

Evgeny Tsymbal Publications

No abstract provided.

Spin-Neutral Currents For Spintronics, D.-F. Shao, S.-H. Zhang, M. Li, C.-B. Eom, And E. Y. Tsymbal

Evgeny Tsymbal Publications

No abstract provided.

Reversal Of The Magnetoelectric Effect At A Ferromagnetic Metal/Ferroelectric Hfo2 Interface Induced By Metal Oxidation, Z. Chen, Q. Yang, L. L. Tao, And E. Y. Tsymbal

Evgeny Tsymbal Publications

No abstract provided.

Transport Spin Polarization Of Noncollinear Antiferromagnetic Antiperovskites, . G. Gurung, D.-F. Shao, And E. Y. Tsymbal

Evgeny Tsymbal Publications

No abstract provided.

Synchronization And Analysis Of Multimodal Medical Data, Nafisa N. Mostofa

Honors Undergraduate Theses

The United States suffers from a significant disparity in the availability of the medical resources and expertise among different regions of the country. Patients in rural areas may not have the opportunity to consult with a physician until their disease progresses to later stages, resulting in a considerable decrease in quality of life. Advances in telemedicine systems that can provide remote communication, medical data acquisition, and medical data analysis promise a significant improvement to early access to medical care and diagnoses for disadvantaged individuals.

In this thesis, we make several contributions on topics that contribute to the improvement of telemedicine …

Analytical Chemistry Of Plastic Debris: Sampling, Methods, And Instrumentation, Robert C. Hale, Meredith E. Seeley, Ashley E. King, Lehuan H. Yu

VIMS Books and Book Chapters

Approaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include …

Transitioning A Mathematics Specialist Preparation Program Into An Interactive Online Program: Insights From The Developer And Candidate Perspectives, Aimee J. Ellington, Allison Yoder

Journal of Mathematics and Science: Collaborative Explorations

This paper will describe how the Virginia Commonwealth University mathematics specialist preparation program transitioned from a face-to-face format to a fully online format. We will describe the technology and instructional methods that are used for course meetings, activities, and assignments. We will describe the development and implementation of a mathematics activity from instructors designing the activity, participants completing the activity, and instructors providing feedback on the activity. One mathematics activity will be shared that demonstrates the process of the program model that includes independent work, small group work, and in-class discussions. We will describe one participant’s experience as she developed …

Nanomaterials In The Environment, Human Exposure Pathway, And Health Effects: A Review, Arindam Malakar, Sushil R. Kanel, Chittaranjan Ray, Daniel D. Snow, Mallikarjuna N. Nadagouda

Daugherty Water for Food Global Institute: Faculty Publications

Nanomaterials (NMs), both natural and synthetic, are produced, transformed, and exported into our environment daily. Natural NMs annual flux to the environment is around 97% of the total and is significantly higher than synthetic NMs. However, synthetic NMs are considered to have a detrimental effect on the environment. The extensive usage of synthetic NMs in different fields, including chemical, engineering, electronics, and medicine, makes them susceptible to be discharged into the atmosphere, various water sources, soil, and landfill waste. As ever-larger quantities of NMs end up in our environment and start interacting with the biota, it is crucial to understand …

Power And Statistical Significance In Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach

All Faculty Scholarship

Event studies, a half-century-old approach to measuring the effect of events on stock prices, are now ubiquitous in securities fraud litigation. In determining whether the event study demonstrates a price effect, expert witnesses typically base their conclusion on whether the results are statistically significant at the 95% confidence level, a threshold that is drawn from the academic literature. As a positive matter, this represents a disconnect with legal standards of proof. As a normative matter, it may reduce enforcement of fraud claims because litigation event studies typically involve quite low statistical power even for large-scale frauds.

This paper, written for …

Epidemic Spread Modeling For Covid-19 Using Hard Data, Anna Schmedding

Dissertations, Theses, and Masters Projects

We present an individual-centric model for COVID-19 spread in an urban setting. We first analyze patient and route data of infected patients from January 20, 2020 ,to May 31, 2020, collected by the Korean Center for Disease Control & Prevention (KCDC) and illustrate how infection clusters develop as a function of time. This analysis offers a statistical characterization of mobility habits and patterns of individuals. We use this characterization to parameterize agent-based simulations that capture the spread of the disease, we evaluate simulation predictions with ground truth, and we evaluate different what-if counter-measure scenarios. Although the presented agent-based model is …

Proton Spin Structure From Simultaneous Monte Carlo Global Qcd Analysis, Yiyu Zhou

Dissertations, Theses, and Masters Projects

Despite the great effort and achievements made towards understanding proton spin structure in the past few decades, a complete picture is still elusive. Parton distribution functions (PDFs), which in quantum chromodynamics (QCD) encode the momentum and helicity distributions of quarks and gluons inside a proton, provide the means by which to quantify the proton structure information. Being inherently nonperturbative, PDFs have to be extracted from unpolarized and polarized lepton-hadron and hadron-hadron scattering data. In particular, experiments that measure unpolarized and polarized jet observables can provide insight into the momentum and helicity distributions of gluons, which have generally been more difficult …

Combining Performance Profiling And Modeling For Accuracy And Efficiency, Hao Xu

Dissertations, Theses, and Masters Projects

Modern computer systems have evolved to employ powerful parallel architectures, including multi-core processors, multi-socket chips, large memory subsystems, and fast network communication. Given such powerful hardware, developers rely on performance profiling and modeling to guide their performance optimization. However, performance optimization is facing new challenges on efficiency and accuracy with emerging computer systems. In this dissertation, we propose approaches to address these challenges. We first study memory contention in Non-Uniform Memory Access (NUMA) architectures. We present DR-BW, a new tool based on machine learning to identify bandwidth contention in NUMA architectures and provide optimization guidance. DR-BW collects performance data with …

Indoor Chemistry: Development Of An Indoor Surface Extractor, Hannah Rose Przelomski

Dissertations, Theses, and Masters Projects

People spend around 90% of their time indoors. This means that indoor air can have an impact on human health. One of the main factors that makes indoor air differ from outdoor air is indoor areas have a higher surface area to volume ratio than outdoor areas. Surfaces give aerosol particles a place to deposit where they can stick or react. Some of this material can leave the surface and reenter the air. Being able to analyze the material on different indoor surfaces will help further the understanding of indoor surfaces’ impact on indoor air. A surface extractor was developed …

Virtual Tutor Personality In Computer Assisted Language Learning, Johanna Dobbriner, Cathy Ennis, Robert J. Ross

Conference papers

The use of intelligent virtual agents in language learning has increased in recent years. Studies into several aspects of personalisation aiming to increase user engagement are an ongoing research topic with avatar personality being one such aspect. As a step towards our development of intelligent virtual avatars, we present two of our initial experiments to explore differences in user interaction with two contrasting avatar personalities -- P1: open-minded, friendly and sociable and P2: closed-off, curt and distant. Each user interacted with a single personality in a video-call setting and gave feedback on the interaction. Our expectations, that P1 would be …

Interactive Learning Approach For Arabic Target-Based Sentiment Analysis, Husamelddin Balla, Marisa Llorens, Sarah Jane Delany

Conference papers

Recently, the majority of sentiment analysis researchers focus on target-based sentiment analysis because it delivers in-depth analysis with more accurate results as compared to traditional sentiment analysis. In this paper, we propose an interactive learning approach to tackle a target-based sentiment analysis task for the Arabic language. The proposed IALSTM model uses an interactive attentionbased mechanism to force the model to focus on different parts (targets) of a sentence. We investigate the ability to use targets, right and left contexts, and model them separately to learn their own representations via interactive modeling. We evaluated our model on two different datasets: …

Acute Growth Inhibition & Toxicity Analysis Of Nano-Polystyrene Spheres On Raphidocelis Subcapitata, Anthony Reynolds, Michelle Giltrap, Gordon Chambers

Articles

Micro/nano-plastics (MNPs) have been found within many environments and organisms including humans, making them a significant and growing concern. Initial research into the potential detrimental effects these MNPs both from acute and chronic exposure has been ongoing but still requires substantially more data to clarify. This research presents the response of nano-polystyrene (NPS) on Raphidocelis subcapitata, a freshwater alga, under an existing acute toxicity test along with additional analytical techniques to try identifying possible sources of toxicity. R. subcapitata cells were exposed for 72 h to a concentration range of 0–100 mg/l NPS. Growth Inhibition (GI) testing showed the …

Power Amplification Strategies Across Animals, Rayhan Asif

Williams Honors College, Honors Research Projects

Animals use muscles for movement, but some have evolved mechanisms to exceed maximum power used in a motion known as power amplification. In this literature review, I analyzed and compared the evolution of structures capable of power amplification between species. Structures capable of power amplification were broken down into the basic components of the engine, amplifier, and tool. The species analyzed were found to possess necessary structures for power amplification which were relatively similar to each other in morphology, but varied greatly in function. The ease with which these structures evolved was evaluated based on the amount of divergence which …

Secure Network Access Via Ldap, Nicholas Valaitis

Williams Honors College, Honors Research Projects

Networks need the ability to be access by secure accounts and users. The goal of this project is to configure and expand on LDAP configurations with considerations for AAA via TACACS+ and Radius for network equipment. This will provide adequate security for any given network in terms of access and prevent lose of access to devices which happens all to often with locally configured accounts on devices.

Preforming A Vulnerability Assessment On A Secured Network, Mathias Sovine

Williams Honors College, Honors Research Projects

A computer network will be built using 3 routers, 1 switch, and 4 computers. The network will be used to simulate the connections between an at home office and the internet. The network will be divided into 3 sub-networks. The routers will be secured using methods like access control lists, changing default admin passwords, and network encryption. The switch will be secured using methods like switchport security and setting access passwords. Once the network is secured, three penetration testing techniques and three exploits will be performed on the network. The results of the exploits and penetration testing techniques will be …

Smart Recycling Bin, Stephen Pirosko, Keith Small, Sergio Orozco, Brandon Bannavong

Williams Honors College, Honors Research Projects

The objective of this project is to design and prototype a device that accepts plastic, aluminum and glass bottles, mixed with other miscellaneous items of trash, and automatically sorts the materials into separate containers. The device will be able to differentiate between acceptable and unacceptable materials and sort them accordingly in order to prevent recycling contamination. The system will use different sensors and image recognition to determine the correct material. Once determined sorting actuators will put the material into the correct bin.

Continuing The Metalation And Ring Closure Of Biliazine, Joshua Villers

Williams Honors College, Honors Research Projects

Continuing previous research conducted by Dr. Ziegler and his Graduate Students in which different metals were selected to metalate the compound Biliazine as well as finding metals that could be used to close the ring system in Biliazine.

The Effects Of Heterogeneities And Syn-Deformational Partial Melting On Rock Strength Evolution And Melt Migration, Nicole Wagner

Williams Honors College, Honors Research Projects

In nature, the segregation of granitic melts at the source may be controlled by fabric and compositional heterogeneities in the source rock, such as foliation and lineation. To investigate the influence of foliation/lineation orientation and composition on rock strength and melt interconnectivity, I performed a series of experiments on cores of a fine-grained gneiss (Gneiss Minuti) and a fine-grained muscovite-bearing quartzite (Moine Thrust quartzite). These rocks were cored at six primary orientations parallel, 45 degrees, and perpendicular to the foliation and lineation and were deformed at a constant temperature of 900°C, pressure of ~2 GPa, and strain rate of ~10-6/s …

Synthesis Of Novel Porphyrin Derived Molecules For The Study Of Self Assembly And Photophysical Properties, Alex Nguyen

Williams Honors College, Honors Research Projects

The photochemical capabilities of self-assembling porphyrins holds the potential to eliminate the use of fossil fuels. Porphyrins have the ability to absorb solar energy to excite its electrons within the highly conjugated π system of the porphyrin ring. The excited electron can then be donated thus creating a charge separated state between the porphyrin donor and the electron acceptor. With self-assembly of porphyrin monomers into a supramolecular structure, this charge separated state can be emphasized and prolonged so the energy potential generated can be harvested. Here, the synthesis of porphyrin derivatives substituted with biologically found molecules is described. The lysine …

Design Project: Smart Headband, John Michel, Jack Durkin, Noah Lewis

Williams Honors College, Honors Research Projects

Concussion in sports is a prevalent medical issue. It can be difficult for medical professionals to diagnose concussions. With the fast pace nature of many sports, and the damaging effects of concussions, it is important that any concussion risks are assessed immediately. There is a growing trend of wearable technology that collects data such as steps and provides the wearer with in-depth information regarding their performance. The Smart Headband project created a wearable that can record impact data and provide the wearer with a detailed analysis on their risk of sustaining a concussion. The Smart Headband uses accelerometers and gyroscopes …

Understanding The Research And Applications Of Quantum Computing, Joshua Foss

Williams Honors College, Honors Research Projects

In-Depth research of current quantum computing understanding and practices. Presentation of possible new and creative applications of quantum computing.

Exploring Plane Partitions, Nicholas Heim

Williams Honors College, Honors Research Projects

The combinatorial theory of partitions has a number of applications including the representation theory of the symmetric group. A particularly important result counts the number of standard Young tableau of a given partition in terms of the hook lengths of the partition. In this paper we explore the analog of the hook length formula for plane partitions, the three-dimensional analog of ordinary partitions. We show that equality does not always hold but we conjecture that a certain inequality holds. Using a computer program, we verify this conjectured inequality for all 1982 plane partitions up to n = 11.

The Effects Of Increasing Positively Charged Metal Ions Within Synovial Fluid, Kandisi Anyabwile

Williams Honors College, Honors Research Projects

Osteoarthritis is a degenerative joint disease that affects 10% of men and 13% of women over age of 60. It is the degradation of the cartilage between two bones; obesity, age, overuse, or injury are major contributors to the development of this disease. The joint is incapsulated by the synovial sac filled with a viscous solution that aids in lubrication referred to as synovial fluid. If the synovial sac is ruptured due to injury, positive ions (K⁺, Na⁺, Ca²⁺, and Fe³⁺) may affect viscoelastic properties within the sac. The purpose of this …