Digital Commons Network^™

Comparison Between The Effects Of Acute Physical And Psychosocial Stress On Feedback-Based Learning, Xiao Yang, Brittany Nackley, Bruce H. Friedman

Psychology Faculty Publications

Stress modulates feedback-based learning, a process that has been implicated in declining mental function in aging and mental disorders. While acute physical and psychosocial stressors have been used interchangeably in studies on feedback-based learning, the two types of stressors involve distinct physiological and psychological processes. Whether the two types of stressors differentially influence feedback processing remains unclear. The present study compared the effects of physical and psychosocial stressors on feedback-based learning. Ninety-six subjects (Mage = 19.11 years; 50 female) completed either a cold pressor task (CPT) or mental arithmetic task (MAT), as the physical or psychosocial stressor, while electrocardiography and …

A Dynamical Systems Approach To Characterizing Brain–Body Interactions During Movement: Challenges, Interpretations, And Recommendations, Derek C. Monroe, Nathaniel T. Berry, Peter C. Fino, Christopher K. Rhea

Rehabilitation Sciences Faculty Publications

Brain–body interactions (BBIs) have been the focus of intense scrutiny since the inception of the scientific method, playing a foundational role in the earliest debates over the philosophy of science. Contemporary investigations of BBIs to elucidate the neural principles of motor control have benefited from advances in neuroimaging, device engineering, and signal processing. However, these studies generally suffer from two major limitations. First, they rely on interpretations of ‘brain’ activity that are behavioral in nature, rather than neuroanatomical or biophysical. Second, they employ methodological approaches that are inconsistent with a dynamical systems approach to neuromotor control. These limitations represent a …

Control Of The Electroporation Efficiency Of Nanosecond Pulses By Swinging The Electric Field Vector Direction, Vitalii Kim, Iurii Semenov, Allen S. Kiester, Mark A. Keppler, Bennett L. Ibey, Joel N. Bixler, Ruben M. L. Colunga Biancatelli, Andrei G. Pakhomov

Bioelectrics Publications

Reversing the pulse polarity, i.e., changing the electric field direction by 180°, inhibits electroporation and electrostimulation by nanosecond electric pulses (nsEPs). This feature, known as “bipolar cancellation,” enables selective remote targeting with nsEPs and reduces the neuromuscular side effects of ablation therapies. We analyzed the biophysical mechanisms and measured how cancellation weakens and is replaced by facilitation when nsEPs are applied from different directions at angles from 0 to 180°. Monolayers of endothelial cells were electroporated by a train of five pulses (600 ns) or five paired pulses (600 + 600 ns) applied at 1 Hz or 833 kHz. Reversing …

Optimal Domain-Partitioning Algorithm For Real-Life Transportation Networks And Finite Element Meshes, Jimesh Bhagatji, Sharanabasaweshwara Asundi, Eric Thompson, Duc T. Nguyen

Civil & Environmental Engineering Faculty Publications

For large-scale engineering problems, it has been generally accepted that domain-partitioning algorithms are highly desirable for general-purpose finite element analysis (FEA). This paper presents a heuristic numerical algorithm that can efficiently partition any transportation network (or any finite element mesh) into a specified number of subdomains (usually depending on the number of parallel processors available on a computer), which will result in “minimising the total number of system BOUNDARY nodes” (as a primary criterion) and achieve “balancing work loads” amongst the subdomains (as a secondary criterion). The proposed seven-step heuristic algorithm (with enhancement features) is based on engineering common sense …

Gradient-Based Trade-Off Design For Engineering Applications, Lena A. Royster, Gene Hou

Mechanical & Aerospace Engineering Faculty Publications

The goal of the trade-off design method presented in this study is to achieve newly targeted performance requirements by modifying the current values of the design variables. The trade-off design problem is formulated in the framework of Sequential Quadratic Programming. The method is computationally efficient as it is gradient-based, which, however, requires the performance functions to be differentiable. A new equation to calculate the scale factor to control the size of the design variables is introduced in this study, which can ensure the new design achieves the targeted performance objective. Three formal approaches are developed in this study for trade-off …

Collaborative Leadership Skills And Competencies In Emergency Management And Resilience: Lessons And Implications From The Response To The Covid-19 Pandemic, Norah Abdullah A Alshayhan

School of Public Service Theses & Dissertations

Collaborative leadership is a critical component in emergency management and resilience. Although cross-sector leadership is considered compulsory in the management of many disasters, the skills and competencies for successful execution of collaborative leadership approaches in emergency management and resilience are still largely unknown, especially as it pertains to the COVID-19 pandemic response. The perspectives of emergency management and resilience leaders may fill in this research gap.

This qualitative study relies on semi-structured interviews to explore the needed skills and competencies for collaborative leadership in emergency management and resilience during the response to the COVID-19 pandemic in the South-Atlantic states. The …

Design And Construction Of A Longitudinally Polarized Solid Nuclear Target For Clas12, Victoria Lagerquist

Physics Theses & Dissertations

A new polarized nuclear target has been developed, constructed, and deployed at Jefferson Laboratory in Newport News, VA for use with the upgraded 12 GeV CEBAF (Continuous Electron Beam Accelerator Facility) accelerator and the Hall B CLAS12 (12 GeV CEBAF Large Acceptance Spectrometer) detector array. This ‘APOLLO’ (Ammonia POLarized LOngitudinally) target is a longitudinally polarized, solid ammonia, nuclear target which employs DNP (Dynamic Nuclear Polarization) to induce a net polarization in samples of protons (NH3) and deuterons (ND3) cooled to 1K via helium evaporation, held in a 5T polarizing field supplied by the CLAS12 spectrometer, and irradiated with 140 GHz …

Using Ozobots To Learn Character Traits, Kimberly Dawn Eure

Teaching & Learning Theses & Dissertations

Technology is utilized in everyday life. As such, teachers can employ educational robots and technology to assist in growing skills in collaboration, communication, computational thinking, and problem-solving. Educational robots also appear to increase engagement and motivation in students to participate in lessons. This study employed design-based research (DBR) to explore the use of Ozobots in teaching character traits in a fourth-grade classroom. Together with fourth-grade teachers, a set of lessons was created that employed Ozobots to engage students in learning character traits. Two technology integration frameworks, technological pedagogical and content knowledge (TPACK) and Substitution, Augmentation, Modification, and Redefinition (SAMR), were …

Modeling The Impacts Of Sea Level Rise In Coastal Virginia At Multiple Scales, George Murray Mcleod Iv

OES Theses and Dissertations

Relative sea level is increasing along the Mid-Atlantic coast of the United States and the rate of relative sea level rise (ΔRSL) for Coastal Virginia is approximately double the rate of global sea level rise (ΔSLRG)(1). The potential impacts posed to communities by ΔRSL are best understood by examining the spatial relationship between the upper limits of ocean-connected waters and the geographic positioning of critical natural and societal assets. This research examines this problem at three spatial scales to quantify the impacts of ΔRSL and storm flooding events on (i) structural and transportation infrastructure for the tide-influenced coastal zone of …

Opensim-Based Musculoskeletal Modeling: Foundation For Interactive Obstetric Simulator, Bahador Dodge

Electrical & Computer Engineering Theses & Dissertations

The use of mathematical and computational models to understand complex biological systems, such as the human birth process, is a rapidly growing field in medicine. These models can be used to optimize and personalize medical treatments for individual patients, enhance training, and aid in educational efforts. While recent advancements in healthcare, particularly in obstetrics, have improved care for mothers and babies, studies and government reports indicate a rising rate of maternal mortality in the United States.

Despite this rising trend, there is a lack of detailed studies concerning the use of modeling and simulation to develop an interactive obstetrics simulator …

Measurements Of Magnetic Field Penetration Of Materials For Superconducting Radiofrequency Cavities, Iresha Harshani Senevirathne

Physics Theses & Dissertations

Superconducting Radio Frequency (SRF) cavities used in particle accelerators are typically formed from or coated with superconducting materials. Currently high purity niobium is the material of choice for SRF cavities which have been optimized to operate near their theoretical field limits. This brings about the need for significant R&D efforts to develop next generation superconducting materials which could outperform Nb and keep up with the demands of new accelerator facilities. To achieve high quality factors and accelerating gradients, the cavity material should be able to remain in the superconducting Meissner state under high RF magnetic field without penetration of quantized …

An Autoethnography On Teaching Antiracism In The Current Sociopolitical Environment, Taylor M. Jacobson

Teaching & Learning Theses & Dissertations

In the course of American history, students from historically marginalized and underrepresented communities have been left out of the educational conversation. This has created an era of undereducated citizens who have historically used privilege to oppress students from these communities. Teachers must use their privilege to teach antiracist education that specifically encourages students to stand up for the justice needed to make a better world. Although this education is important, politicians, parents, and school board administrators are consistently putting teachers in an awkward position when they work towards implementing antiracist education by enacting policies that force them to stop or …

Terrence Loves You, Quentin Dakota Steadman

English Theses & Dissertations

TERRENCE LOVES YOU is a novel that highlights the queer, working-class South and the lifelong navigation between past trauma and present adversity - how these upheavals nourish a lifelong resignation for the future, convincing us we have no control over Fate.

In stories irrational as they are visceral, we follow Damian as he experiences the world on the heels of his transient and independent mother. From the backwoods of Kentucky to a nightmarish carnival, from a guitar store heist to the criminal underworld of Music City U.S.A., Damian is left stumbling behind, bearing witness to a disfigured love. When Damian …

Electric Vehicle Routing Problem – Models And Algorithms, Hesamoddin Tahami

Engineering Management & Systems Engineering Theses & Dissertations

The transportation sector is a major greenhouse gas emitter that is heavily regulated to reduce its dependence on oil. These regulations along with the growing customer awareness of global warming have led to the investigation of new transportation problems that consider using eco-friendly vehicle fleets. Promising alternatives to traditional fleets include alternative fuel vehicles (AFVs) and electric vehicles (EVs). These twenty-first-century vehicles offer an appealing advantage of consistently reducing their environmental impact, but due to the current technology, they exhibit bothersome limitations. The short driving range along with limited charging infrastructure may consequently cause issues related to range anxiety, i.e., …

Nanosecond Pulsed Electric Field Modulates Electron Transport And Mitochondrial Structure And Function, Lucas Nelson Potter

Biomedical Engineering Theses & Dissertations

Pulsed power treatment has been used to induce regulated cell death (RCD) in cells or ablate tumors in animals. A subset of pulsed power as electroporation with high voltage and pulse duration of milliseconds is used for biomedical treatment to induce pores in the plasma membrane of cells. Nanosecond Pulsed Electric Fields (nsPEFs)– an extension of electroporation, uses waveforms with pulse durations on the order of 10-900 nanoseconds. nsPEF treatment has demonstrated intracellular effects for potential biomedical applications. In this work, nsPEF treatment is used to demonstrate changes that affect viability, plasma membrane permeability ROS (Reactive Oxygen Species) in the …

Near Transfer After Direct Instruction: An Experimental Inquiry Within Aviation Technician Training, Francis Eamonn Powers

STEMPS Theses & Dissertations

This study put forth two instructional interventions set within a direct instruction (DI) framework specific to an aviation maintenance context. To evaluate the effectiveness of these two training interventions a criterion was established to measure near transfer during a performance evaluation on a live aircraft. Information learned within this study indicates that DI can be highly effective in technical training environments. This study also articulates how VR experiences may be included within these types of training contexts and discusses the factors and affordances that come with utilizing VR in instructional activities.

Additionally, this study revealed experiential characteristics of a DI …

Supporting Account-Based Queries For Archived Instagram Posts, Himarsha R. Jayanetti

Computer Science Theses & Dissertations

Social media has become one of the primary modes of communication in recent times, with popular platforms such as Facebook, Twitter, and Instagram leading the way. Despite its popularity, Instagram has not received as much attention in academic research compared to Facebook and Twitter, and its significant role in contemporary society is often overlooked. Web archives are making efforts to preserve social media content despite the challenges posed by the dynamic nature of these sites. The goal of our research is to facilitate the easy discovery of archived copies, or mementos, of all posts belonging to a specific Instagram account …

Validation Of Meta Motion Imu Sensors Through Measurement Of Knee Angles During Gait, Kerri Caruso

Biomedical Engineering Theses & Dissertations

The implementation of inertial measurement units (IMU) in the biomechanical field has become increasingly popular due to their robustness, simplicity, accuracy, and the ability to move research out of a lab and into the real world. In this study, the MetaMotion IMU sensors are assessed for validity against a dynamometer and the Vicon motion capture system. Both systems have proven their measuring accuracies in the biomechanics world and are used as the truth source for this validation study. In the first part of this study, the sensors are assessed for various common sensor errors. Individual sensor components of the IMU, …

Examining The Relationship Between Program Satisfaction, Credential Earnings, And Gender On Full-Time Employment Outcomes Of Career And Technical Program High School Graduates In Virginia, Margaret J. Turley

STEMPS Theses & Dissertations

Career and technical education (CTE) incorporates occupational skills, workforce readiness skills, and credentials that make high school graduates better prepared for the workforce. Students who complete CTE programs of study have higher employment rates after high school graduation and often go on to postsecondary education. For those who do not go on to postsecondary education, CTE programs can provide opportunities for increased earnings and more access to the labor market.

This quantitative study used binary logistic regression, using data collected by the Center for Survey Research of the University of Virginia’s Weldon Cooper Center to examine if satisfaction with CTE …

Sealion Cubesat Mission Architecture Using Model Based Systems Engineering With A Docs As Code Approach, Kevin Yi-Tzu Chiu

Mechanical & Aerospace Engineering Theses & Dissertations

CubeSats are a growing population within the space industry. Every year, universities launch numerous amounts of CubeSats due to their inexpensive cost of development, launch, and deployment. However, this comes with numerous challenges. As the number of university-CubeSats grow, so too do the numbers that fail. With development teams consisting mainly of students with little to no training, proper and yet easy to use tools or methods should be implemented to help ensure mission success. Especially in the critical stages of planning before and during development, a technical approach to quickly track life cycle development of a CubeSat is needed. …

Climbers’ Risk Perceptions Of Erosion From Flooding At Carderock Recreation Area, Chandler J. Berry

Human Movement Studies & Special Education Theses & Dissertations

Through increased temperature, precipitation, frequency of extreme weather, flooding, drought, and fire, climate change will alter where and how people can recreate. Extant research illustrates the effects of climate change on a variety of outdoor recreation activities; however, little research has been completed on the effects of climate change on rock climbing outside of the alpine environment. One such impact found at Carderock Recreation Area is riverine flooding and erosion. This study used a quantitative survey research design to understand how risk perceptions of erosion from flooding are affected by place attachment and the past use history of rock climbers …

Nb3Sn Coating Of Twin Axis Cavity And Other Complex Srf Cavity Structures, Jayendrika Kumari Tiskumara

Physics Theses & Dissertations

In the field of Accelerator Science, for the low cost and increased quality factor, thin films coated niobium cavities are used in the modern SRF research. Within the potential substances, Nb₃Sn has shown higher critical temperature than niobium. Here the tin vapor diffusion method is used as the preferred technique to coat niobium cavities. So far, only elliptical cavities have been coated with Nb₃Sn and this technique has not yet been applied to cavities with complex geometries, which are also helpful in the accelerator science field. The Half-wave resonator could provide us data across frequencies of …

Cardiac Ablation And Stimulation With Nanosecond Pulsed Electric Fields (Nspefs), Federica Serra

Biomedical Engineering Theses & Dissertations

Surgical ablation of cardiac tissue is the definitive treatment for the most common arrhythmia, atrial fibrillation. In current medical practice, myocardial tissue is often ablated by the application of radiofrequency (RF) currents which are delivered through an electrode to create lesions that block the electrical pathways that sustain reentrant arrhythmias and restore the normal heart rhythm. An alternative to RF is cryoablation, during which the endocardial or epicardial tissue is brought in contact with a cryoprobe. Both RF ablation and cryoablation have significant limitations. In RF ablation, tissue is heated in order to ablate it, but it is an open …

Towards A Formal Theory Of Humor In Organizations, Richard Joseph Hayes

Psychology Theses & Dissertations

Current theories and models of humor conceptualize humor at the individual, dyadic, and organizational level. These theories laid the foundation for research and empirical findings that have established humor’s impact in the workplace. Yet, because these theories are not integrated, they individually do not offer a comprehensive view of humor in the workplace across different levels, hindering the development of multilevel research designs. Additionally, the ambiguity of these narrative theories hampers empirical testing precision. This dissertation expands the literature by introducing a mathematical, multilevel model of humor and tests that theory using computational simulation methods. Synthetic environments reproduced observed correlations …

Generation Of Plasma With A Rotating Electric Field, Franklin Price Mosely

Electrical & Computer Engineering Theses & Dissertations

Nonthermal plasma generation is an important area of research that has many applications ranging from semiconductor production to medical applications including the treatment of cancers and sterilization of surfaces. Specific radicals and excited species and discharge powers are critical for the successful completion of these processes. It is important that these excited species are shown to be achievable for a given discharge system without leading to instabilities such as arcing.

The present thesis details the design, fabrication, testing, and analysis of a novel plasma generation system based on multiphase excitation. As predicted by theory, the experimental results demonstrate that a …

Human Psychology Factors Influencing Agile Team Autonomy In Post-Pandemic Remote Software Organizations, Ravikiran Kalluri

Engineering Management & Systems Engineering Theses & Dissertations

Agile project management methods are gaining in popularity in the software industry as software development teams are being asked to be adaptive to market needs and resilient to change and uncertainty. With increasing market uncertainty, global competition, and time-to-market pressure, it is becoming a challenge to develop an innovative product and deliver it on-time without the opportunity that comes from team autonomy to experiment and learn from failures in a remote workplace. To resolve this challenge, it is critical to understand the myriad human psychological factors in play that influence Agile team autonomy in a remote work environment.

The role …

Information And Communications Technology Within Coastal Resilience Planning Frameworks: The Case Of Jamaica, A Small Island Developing State, Ren-Neasha R. Blake Gilmore

School of Public Service Theses & Dissertations

Coastal areas increasingly grapple with coastal hazards like hurricanes, tropical storms, sea level rise, and flooding. Proactive and agile coastal resilience solutions are necessary to reduce such risks and their associated socio-economic and environmental impacts. For these reasons, global coastal planners are pursuing climate action through multi-sector collaborations, innovative hybrid natural and manufactured solutions, and feasible mid to long-term coastal resilience strategies. While climate action is high on governments’ agenda globally, integrating information and communications technology has diffused widely within the coastal planning space in small island developing states, drawing on more technology-driven solutions. Very few empirical studies in the …

Roboretrieve--In A Dual Role As A Hand-Held Surgical Robot And A Collaborative Robot End-Effector To Perform Spillage-Free Specimen Retrieval In Laparoscopy, Siqin Dong

Mechanical & Aerospace Engineering Theses & Dissertations

Recent advances in surgical robotics attempt to overcome limitations of manual surgery by augmenting the surgeon’s capabilities while performing suturing, incision, retraction, and retrieval tasks. This dissertation presents novel approaches for spillage-free specimen retrieval in confined spaces, targeted toward the surgical domain of minimally invasive robotic surgery. The retrieval task involves extraction of a resected specimen, residing in the abdominal cavity, completely outside of the patient’s body. A major challenge in this context is the spillage of content being retrieved, which may cause dissemination of malignancy. To address this challenge, this dissertation develops RoboRetrieve, a portable hand-held robot that …

Iot Health Devices: Exploring Security Risks In The Connected Landscape, Abasi-Amefon Obot Affia, Hilary Finch, Woosub Jung, Issah Abubakari Samori, Lucas Potter, Xavier-Lewis Palmer

School of Cybersecurity Faculty Publications

The concept of the Internet of Things (IoT) spans decades, and the same can be said for its inclusion in healthcare. The IoT is an attractive target in medicine; it offers considerable potential in expanding care. However, the application of the IoT in healthcare is fraught with an array of challenges, and also, through it, numerous vulnerabilities that translate to wider attack surfaces and deeper degrees of damage possible to both consumers and their confidence within health systems, as a result of patient-specific data being available to access. Further, when IoT health devices (IoTHDs) are developed, a diverse range of …

Firm Capabilities, Great Power Competition, And The Structural Reshaping Of Globalization, Samuel Wilson

Theses and Dissertations in Business Administration

The changing nature of modern globalization has given rise to strategic competition between great power states, who utilize global firms and policy interventions in commercial markets to pursue state-level objectives. Multinational executives operating in global markets must contend with the consequences of great power competition between countries like the US and China, developing novel strategies and capabilities to defend firm performance in the face of trade wars and geopolitical confrontation. Through the analysis of risk factor disclosures of foreign multinational firms operating in China, as well as cases of Chinese economic and industrial espionage against US firms, this study utilizes …