Engineering Commons^™

Local Charge Distortion Due To Cr In Ni-Based Concentrated Alloys, Jacob Fischer

All Theses

Due to the presence of multiple elements consisting of a range of atomic radii, local lattice distortion (LLD) is commonly observed in concentrated (and high entropy) alloys. However, since these elements also have diverse electronegativities, recent works show that atoms can have a range of atomic charges. In this work, using density functional theory (DFT), we investigate electronic charge distribution in face centered cubic (FCC) Ni-based alloys and find significant charge-density distortion in HEAs. Specifically, Cr atoms have large charge density distortion that results in a wide range of bond lengths, atomic charges, and electronic density of states in Cr-containing …

Trust: The Inertia Taxonomy Of Trust And Learning Outcomes Of Trust Building Exercises, Ann B. Lyons

All Theses

This study investigates United States construction professionals’ view of trust in the workplace. In particular the focus is on building trust through trust building exercises. In order to accomplish this, a literature review was conducted focusing on trust in the worldwide construction industry. This was followed by interviews with US construction professionals who focus on team building. These interviews informed a survey sent to a wide variety of US construction professionals. The survey had two sections of content questions, 1. view of trust indicators and 2. perception of trust building exercises. Finally, experts in the field of construction team building …

Predicting The Ductility Of Tungsten Based Bcc Refractory High Entropy Alloys: A Computational Science Driven Study, Akshay Korpe

All Theses

Bcc refractory high entropy alloys (HEAs) are a relatively new category of metallic alloys that promise excellent irradiation resistance and strength retention at high temperatures but exhibit brittle behavior at room temperatures limiting their formability. Understanding the deformation mechanisms and predicting their ductility at room temperature is a topic of interest in contemporary research.

In this work, multiple independent ductility criteria for quantifying the ductility of these HEAs were studied, calculated and compared using Density Functional Theory (DFT) calculations and continuum mechanics frameworks. These ductility parameters were calculated for various W-Ta-Cr-V alloys and the trends were analyzed for each criteria …

Developing An Assessment Tool For Ideation Effectiveness: A Survey-Based Approach For The Shah’S Method Of Design Space Exploration, Venkat Jaya Deep Jakka

All Theses

The research is focused on creativity in engineering design. The goal is to understand if creativity in engineering design can be assessed using a less resource-intensive approach, specifically a survey, compared to design exercises. The survey builds on the metrics established by Shah and colleagues. The four metrics are Novelty, Quality, Variety and Quantity. The metrics are measured with the help of a design activity that is deployed to the participants. These metrics have been used in comparative analysis to assess treatments such as new design methods and personality types. However, the downside of the metrics is that they require …

Expandable Tissue-Engineered Living Surgical Pulmonary Heart Valve For Pediatric Patients, Jacob M. Lautenschlager

All Theses

Cardiovascular disease is the most common cause of mortality in developed countries, with 607.74 million cases globally in 2020.^1,2 Advances in medicine have changed the current demographic suffering from heart valve disease into an aging population suffering from degenerative heart valve disease, creating a growing population treated by surgical or transcatheter intervention.^3-6 Current treatments of valvular heart disease are therefore directed toward valve replacements for the adult population, leaving a treatment gap for pediatric patients suffering from heart valve disease.^7-10

Congenital heart defects are defined as structural abnormalities of the heart or intrathoracic great vessels and are …

Extraction Of Neutron-Gamma Irradiated Diffusion Pump Oils, Cooper L. Tillman

All Theses

This work successfully demonstrates solvent extraction methods for separation of oil from the by-products when two commercially available vacuum pump oils were exposed to an intense neutron and gamma-ray radiation environment. Nuclear fusion power at a commercial scale has accelerated the need for radiation resistant vacuum technology, such as oil-based diffusion pumps. Polyphenyl ether and aromatic silicone oils were irradiated at the Rhode Island Nuclear Science Center (RINSC) up to MGy absorbed doses with neutron and gamma-ray radiation. Solvent extractions were performed using hexane and isopropanol to characterize the oil extraction as a function of total absorbed dose. The by-products …

Hydrogen Isotope Exchange On Diffusion Pump Oils, Carson G. Allen

All Theses

The extent of isotopic exchange of deuterium and tritium with protium atoms in hydrocarbon pump oil was investigated as a means to quantify the chemical stability of a mineral oil, a silicone oil, and a polyphenyl ether oil as candidates for implementation in a diffusion pump. In its target application at a fusion power plant, a chemically stable and radiation hard oil offers substantial reductions in tritium inventory, electrical consumption, and operational pump expenses over alternate solutions for vacuum induction. Select oils were introduced to deuterium and tritium isotopes in a high temperature environment, analogous to an operating vacuum pump. …

Using Efficient Vision Transformers To Improve Perception Systems In Autonomous Off-Road Vehicles, Adam S. Pickeral

All Theses

The development of autonomous vehicles has become one of the greatest research endeavors in recent years. These vehicles rely on many complex systems working in tandem to make decisions. For practical use and safety reasons, these systems must not only be accurate, but also be quick to make decisions. In Autonomous Vehicle research, the environment perception system is one of the key com- ponents of development. The environment perception system allows the vehicle to understand its surroundings using cameras, light detection and ranging (LiDAR), and other sensor systems or modalities. Deep learning computer vision algorithms have shown to be the …

Assessing Even Flat-Fan Nozzles For Spot Spray Herbicide Applications, Thiago H. Vitti

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Herbicide efficiency in row-crop agriculture can be improved using precision technologies for controlling weeds and minimize agronomic, economic, and environmental impacts. Site-specific weed management technologies, such as spot-sprayers, allow herbicides to be sprayed only where weeds are present in the field. Understanding application parameters and their influence on weed control for site-specific spot-spray applications is essential. This research involved laboratory and greenhouse studies to investigate the coverage and coefficient of variation (CV) of even flat-fan spray nozzles under different spot-spray application scenarios, as well as the effect of weed size and application method on the control of various weed species …

Experimental And Computational Investigation Of Green Laser Propagation Through Turbulent Medium In A Water Tank, Richard Owusu Adansi

Open Access Theses & Dissertations

Turbulence medium poses significant challenges to the propagation of laser beams, impacting applications such as free-space optical communication, remote sensing, and laser weapons systems. Therefore, comprehending and mitigating turbulence effects are vital for enhancing the performance of these systems. Analysis of a strong turbulence impact on electromagnetic wave propagation requires extensive knowledge of the Earth's atmospheric and Oceanic phenomena and Maxwell's electromagnetic theory of light as a propagating wave of electric and magnetic fields. Optical systems' propagation often encounters Strong Turbulence, causing interference and diffraction. Nonetheless, light propagation through randomly fluctuating media has been an exciting and active area of …

Reactive Processing Of Hf-Nb-Ti-Ta Melts Into A B4c/C Packed Bed, Laura Leticia Sandoval

Open Access Theses & Dissertations

The reactivity of liquid Hf-Nb-Ti-Ta alloy in B4C/C packed bed to form boride-carbide precipitates for ultra-high temperature ceramics was investigated at 2800 K. The objectives were to predict the thermodynamic phases formed and verify them with microstructural characterization. A pseudo-isopiestic technique was used to significantly lower the oxygen potential as the liquid Hf alloy infused and reacted into a B4C packed bed within a graphite enclosure. The technique had a low temperature region (at 1300 K) to control the oxygen potential with a Y-Al/Y2O3-Al2O3/carbide mixture as a liquid Hf alloy at 2800 K and reacted with B4C/C. In addition, any …

Home Care Work Of Caregivers For Mexican American Adults With Dementia: A Culturally Informed Model Integrating Work System Analyses And Health Disparities Research Framework, Laura Cristina Tovar Felix

Open Access Theses & Dissertations

Dementia is an umbrella term for different diseases such as Alzheimer's, vascular dementia, Lewy body, frontotemporal, and mixed dementias. Dementia is caused by a variety of diseases that cause damage to brain cells interfering with the ability of brain cells to communicate between each other. Dementia is associated with different types of brain cell damage in a specific region of the brain (What Is Dementia?, 2024).Dementia affects 55 million people worldwide, where the most affected population is the low-income and the middle-income countries. (Greenblat, 2023). Every 20 years the number almost double, and by 2039 is estimated to reach 78 …

Development Of Electric Vehicle Charging Station Microgrid With Simulation Modelling, Tenzin Lhaden

Open Access Theses & Dissertations

The rapid adoption of electric vehicles (EVs) necessitates innovative solutions to overcome challenges in energy management, sustainability, and grid reliance. This research develops a hybrid simulation model for EV charging stations, integrating renewable energy sources, such as solar photovoltaic (PV) systems, with energy storage systems (ESS). Leveraging discrete-event simulation (DES) and agent-based modeling (ABM) in AnyLogic, the model offers a comprehensive analysis of charging station operations, incorporating stochastic EV arrivals, dynamic energy allocation, and user-defined customization.Key contributions include the development of hybrid simulation model integrating solar PV, energy storage, and energy management systems (EMS) that dynamically optimizes energy distribution from …

Alabama Women Part 1 (Before 1900), Ashley S. Mcguire

Patent Coloring Books

Patent coloring book

Power Controller For Insulated Solar Electric Cooker, Ryan Koshy, Justin Tae-Hoon Kim

Electrical Engineering

Insulated Solar Electric Cookers, or ISECookers, are devices created to aid those in impoverished regions improve safety, sustainability, and quality of life regarding their cooking practices. ISECookers present an alternative to traditional biofuel/biomass energy sources and provide a closed-loop, self-sustaining system that can be used in a variety of environments. These devices present solutions to widespread issues such as pollution, deforestation, and hazardous emissions as a result of traditional cooking in developing regions around the world. A notable obstacle of these devices is power delivery. Given the varying conditions experienced by a solar panel (inclement weather, irradiance irregularities, etc.), it …

Organizational Reliability And Resilience As A Dynamic System: Knowledge Modeling With Fuzzy Cognitive Maps, Antonie J. Jetter, Ahmed A. Alibage, Nan Peter Liang

Engineering and Technology Management Faculty Publications and Presentations

Safety research in complex environments recommends that high-hazard industries improve reliability and increase their capacity for resilience by enacting principles for high-reliability organizing (HRO). This view has been highly influential in many industries, ranging from aviation to hospitals, and is at the core of many safety culture programs. However, even though HRO principles originated in business practice and were observed in diverse organizations, practitioners frequently struggle to enact them in the contexts of their work. This is likely caused by two limitations of current research: principles are insufficiently specified and the interdependencies between them, such as mutually reinforcing vs. tradeoff …

Power Resilience Planning Under The Threat Of Artificial Intelligence, Chip Corbett, Cuong Nguyen, Dahm M. Hongchai, Prajakta Thorat, Pavithra Prasad, Sarah Von Schimmelmann, Charles M. Weber, Timothy R. Anderson

Engineering and Technology Management Faculty Publications and Presentations

The earth is an unstable planet. Change is constant and frequently chaotic. It is very important to plan carefully to manage changes that can be anticipated now, and to cover potential issues that might not yet have been discovered. The dawn of artificial intelligence (AI) presents a host of new concerns and opportunities. The criteria for evaluation are diverse and complex. Cybersecurity is absolutely essential, yet advances in technology have created an internet of things (IoT) where threat vectors might gain access to critical command and control elements through trillions of connected IoT devices. Whereas elegant zero trust cybersecurity models …

Quantifying Relationships In Fuzzy Cognitive Maps Based On Content Analysis Of Unstructured Research Texts, Ahmed Alibage, Antonie J. Jetter, Elpiniki Papageorgiou

Engineering and Technology Management Faculty Publications and Presentations

FCM projects often rely on knowledge-based approaches, such as expert interviews, which can be challenging to conduct because they require extensive expert participation. We propose a novel alternative to create FCM models based on expert knowledge that is already codified in research texts and other publications. In this approach, thematic network analysis identifies FCM concepts and signed causal connections, while computation of t-coefficient is used to determine the weights of the identified edges. We introduce and evaluate the approach in the context of a real-world system modeling project that is based on 47 carefully selected, peer reviewed research publications on …

Improving Attendance To Achieve Organizational Goals: A Case Study Of Human-Centered Design In A Small Us Plant-Based Food Manufacturer, Angel Contreras-Cruz, Eduardo Ahumada-Tello

Engineering and Technology Management Faculty Publications and Presentations

Plant-based food manufacturing companies face high staff turnover rates and attendance problems. It is challenging for those companies to maintain an acceptance level of employee retention and attendance to achieve their objectives. Companies rely on front-line employees to meet production plans, but employees who do not show up at work jeopardize companies' operations. Additional challenges, such as retaining and attracting talent after the COVID-19 pandemic, are present daily for several U.S. organizations. This study analyzes attendance data from the case study company to design an attendance policy. Attendance data suggested that nearly 60 percent of the operational workforce had attendance …

Mental Models Of Translational Scientists, Rasnia Tabpla, Antonie J. Jetter

Engineering and Technology Management Faculty Publications and Presentations

Translational science aims to bridge the gap between scientific discoveries and practical application yet faces challenges in achieving high success rates. This study examines the effective engagement of translational scientists, who play a key role in the translation process. It uses Fuzzy Cognitive Maps (FCMs) to analyze the scientists' mental models and identify common concepts related to success factors, such as ability, resources, opportunity, and entrepreneurial competencies. It then compares the mental models of the scientists and finds that mental models exhibit similarities, yet variations exist such as density and connectedness. Scenario analysis with FCM is then used to identify …

Technology Convergence And Its Influence On Innovation Networks: An Assessment Of Emerging Trends, Shuying Li, Wudan Ma, Xiaoyu Wang, Xian Zhang, Haiyun Xu, Edwin Garces, Tugrul U. Daim

Engineering and Technology Management Faculty Publications and Presentations

AI-age technologies will evolve at an accelerated pace, driven by long-term mutually beneficial symbiosis. Technology convergence will disrupt existing industrial technology fields in general. Assessing and predicting technology convergence will become an important technology management issue in the AI era, providing new clues for distinguishing key technologies in innovation. Existing analytical models prefer to detect retrospective convergence. The role of emerging converging technologies in developing new technologies, generating new applications, and facilitating collaboration and commercialization across different phases is not well understood. In this paper, we build a technology co-occurrence network from the perspective of technology evolution and community detection, …

Iot Technologies To Enable Location Based Services (Lbs) For Smart Tourism, Dharmik Chhatbar

University Honors Program Senior Projects

Location-based Services (LBS) are special types of services that are triggered to deliver certain content (e.g., text, image, video) to users with respect to the users’ exact or approximate location or proximity to certain points of interest. LBS can address the field of smart museums with a goal of enhancing the museum experience for visitors with dynamic and personalized content. In this UHP thesis, we explore a set of Internet of Things (IoT) technologies that can enable the work of LBS in the field of smart museums. The project envisions an immersive museum journey where visitors can seamlessly access interactive …

Bi-Modal Excitation Of A Supersonic Rectangular Jet, Benjamin Malczewski

Doctoral Dissertations and Master's Theses

This work addresses the issue of supersonic rectangular jet noise via bi-modal excitation. A Mach 1.5 heated rectangular jet with a 2:1 aspect ratio is considered. Theoretical work is presented in which a Reduced-Order Model (ROM) is used in conjunction with the Linearized Euler Equations to predict the nonlinear growth and decay of various frequencies due to the interaction between harmonically related modes and the mean flow. Scope is limited to a symmetric disturbance. The case of no interaction is used to help identify a dominant coherent structure, referred to as “f”. For the symmetric disturbance, a Strouhal number of …

Technology Acceptance Of Virtual Reality For Aircraft Maintenance Training, Lusine Carlsson

Doctoral Dissertations and Master's Theses

A study was conducted to investigate Virtual Reality (VR) technology acceptance for aircraft maintenance training by student mechanics. The study employed a survey methodology using the extended Technology Acceptance Model (TAM) as the theoretical framework. Participants were student mechanics from Federal Aviation Administration (FAA) approved aircraft maintenance schools within the United States. The study attempted to address how the variables of perceived usefulness (PU) and perceived ease of use (PEU) influence the students' behavioral intention (BI) to use VR technology for aircraft maintenance training, and how external variables of self-efficacy (SE), perceived enjoyment (PE), perceived health risk (PHR), performance expectancy …

Harnessing Nlp And Large Language Models For Pattern Discovery And Information Extraction In Electric Health Reports, Mina Esmail Zadeh Nojoo Kambar

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, we report on a series of natural language processing tools and models to improve the efficiency and accuracy of information discovery from clinical trials and pharmacological studies. Our main contributions are: 1. The development of an open-source platform Tri-AL that • Enables dynamic tracking of clinical trials information over time, • Excels in data visualization and user interaction with a particular emphasis on enhancing the analysis and representation of race and ethnicity data to foster equity in clinical research, and • Includes a predictive model utilizing machine learning to decipher drug mechanisms of action. 2. Heterogeneous Graph …

Image Processing Techniques For Water Droplet Penetration Time And Contact Angle Estimation, Sai Balaji Jai Kumar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water droplet behavior on soil surfaces plays a critical role in numerous environmental processes, including soil erosion, hydrological dynamics, and ecosystem health. Accurate characterization of soil water repellency, quantified by parameters such as water droplet penetration time (WDPT) and contact angles (WDCA), is essential for informed decision-making in agricultural management, forestry practices, and land-use planning. Despite the significance of these parameters, challenges exist in reliably estimating them due to the complex and dynamic nature of soil-water interactions. This thesis address challenges in estimating WDPT and WDCA, by leveraging state-of-the-art image processing techniques and machine learning algorithms. The research focuses on …

Dynamic Model Of An Overhead Crane, Leonard Ruesga

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis a novel spatial model of an overhead crane was developed. The model includes: bridge, trolley, driving and follower wheels for the bridge and trolley, drum, cable, and the payload. The model accounts for the winding/unwinding of the cable around the drum as the payload is raised/lowered. The cable and the payload were considered as rigid bodies with uniformly distributed mass. First, the kinematic equations of the model were developed by using constraint equations. Second, the dynamic equations were derived through use of Newton’s Laws. Developing the rotational dynamic equations required the determination of the angular momentum vectors …

A Heuristic Approach To Operations And Control Of Btm-Ders For Bill Management And Grid Services, Md Arshad Rashid Shaon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Behind-The-Meter (BTM) distributed energy resources (DERs) have emerged as a critical and transformative force within the energy sector. These decentralized energy assets, which include solar photovoltaic (PV) systems, battery energy storage systems (BESS), and thermostatically controlled loads (TCLs), are increasingly essential for empowering customers by granting them greater control over their energy production and consumption, thereby reducing reliance on centralized power sources. Additionally, they have the potential to play a pivotal role in enhancing grid resilience by providing grid services. This study investigates the management of customer electricity bills and grid services through the integration of various BTM-DERs, particularly solar …

A Hierarchical Framework For Interpretable, Safe, And Specialised Deep Reinforcement Learning, Ammar Abbas

Doctoral

Safety-critical systems, which are crucial for human safety and the environment, are difficult to control and operate. Traditional controllers need precise models of these complex systems, which is hard to develop. \acrfull{drl} offers a potential solution by learning from interactions rather than detailed models, but it faces limitations such as non-transparent decision-making and an expensive, unsafe learning process. Additionally, a key challenge in DRL is ensuring effective decision-making in rare situations.

This thesis proposes a novel approach called the \acrfull{prop_frame} that enables safe and reliable control of critical systems. SRLA combines probabilistic modelling with reinforcement learning to create an interpretable …

Magnetic Sensor Compensation Utilizing Factor Graph Estimation, Frederic W. Lathrop, Clark N. Taylor, Aaron Nielsen

Faculty Publications

Recently, there has been significant interest in the ability to navigate without GPS using the magnetic anomaly field of the Earth (magnav). One of the key technical bottlenecks to achieving magnav is obtaining an accurate magnetic sensor calibration, taking into account own-ship and sensor effects. The Tolles-Lawson magnetic calibration method continues to be the industry standard and was developed when airborne magnetic survey aircraft were first employed over 70 years ago. In this paper, we present a magnetic calibration algorithm based on a factor graph optimization using inertial measurements as well as inputs from both a vector and scalar magnetometer. …