Digital Commons Network^™

Near-Wall Void Distribution Characterization In Pebble Bed Reactor Using Gamma-Ray Ct And Dem Simulation, Ahmed Jasim, Mauricio Maestri, Abdullah Al Zubaidi, Omar Farid, Muthanna Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Accurate characterization of void-fraction distributions in pebble-bed reactors (PBRs) is essential for predicting flow, heat transfer, and neutronic behavior. High-fidelity experimental benchmark data for validating such predictions remain scarce, largely due to the challenges of non-invasive measurements. In this study, gamma-ray computed tomography (CT) was employed to measure radial and cross-sectional porosity in a laboratory-scale pebble bed containing 6cm graphite pebbles. A Discrete Element Method (DEM) simulation was implemented and validated against these measurements, then applied to the full-scale geometry of the Xe-100 high-temperature gas-cooled pebble-bed reactor. Analyses included radial and axial void-fraction profiles in the cylindrical section and conical …

Graphene Synthesis: A Reactor-Oriented Review Of Conventional And Emerging Production Methods, Paul C. Ani, Zeyad Zeitoun, Hasan J. Al-Abedi, Joseph D. Smith

Chemical and Biochemical Engineering Faculty Research & Creative Works

Graphene's unparalleled electrical, mechanical, and thermal properties have positioned it as a transformative material across diverse sectors, including electronics, energy storage, biomedicine, and environmental remediation. However, scalable, cost-effective, and high-quality production remains a critical challenge. This review presents a comprehensive, reactor-oriented analysis of both conventional and emerging graphene synthesis methods, categorized into top-down and bottom-up approaches. Special emphasis is placed on the role of reactor configurations in determining product quality, layer control, scalability, and economic viability. Key synthesis techniques explored include chemical vapor deposition (CVD), epitaxial growth, electrochemical exfoliation, ultrasonic-assisted methods, microwave reactors, combustion synthesis, and plasma-enhanced processes. By evaluating …

A Dataset Of Precipitate-Containing Multi-Principal Element Alloys, Anshu Raj, Xin Wang, Matthew Luebbe, Haiming Wen, Kun Lu, Shuozhi Xu

Materials Science and Engineering Faculty Research & Creative Works

We report a curated dataset that brings together composition, processing conditions, microstructural details, and mechanical properties for 396 combinations of alloy composition and processing condition drawn from 100 peer-reviewed research articles on precipitate-containing multi-principal element alloys (MPEAs). The dataset was created by first utilizing a generative large language model for information extraction, followed by expert review to ensure accurate recovery of materials data. Compositional information was taken directly from tables and text, while processing routes — including homogenization, rolling, recrystallization, and aging — were converted into uniform temperature and time metrics. Microstructural descriptors, including precipitate phases and sizes, were consolidated …

Corrigendum To “Advanced Techniques In Quartz Wafer Precision Processing: Stealth Dicing Based On Filament-Induced Laser Machining” [Opt. Laser Technol. 171 (2024) 110474] (Optics And Laser Technology (2024) 171, (S0030399223013671), (10.1016/J.Optlastec.2023.110474)), Yun Wang, Yutang Dai, Farhan Mumtaz, Kaiyan Luo

Electrical and Computer Engineering Faculty Research & Creative Works

The authors regret, that the affiliation for author Yun Wang was incomplete. To accurately reflect both the author's academic affiliation and the research platform where the work was conducted. The correct affiliation for Yun Wang is updated as above. The authors would like to apologize for any inconvenience caused.

Visual Pattern Mining With Similarity Metrics For Model-Free Trading In The Korean Futures Market, Juhyeon Jang, Jaeyun Kim, David Enke

Engineering Management and Systems Engineering Faculty Research & Creative Works

The fractal market hypothesis highlights multi-scale dynamics in financial time series and provides a theoretical foundation for pattern-based analysis. This study proposes a model-free visual pattern mining framework that transforms high-frequency market data into image representations to support intelligent decision-making. By converting 1-minute KOSPI200 futures data into candlestick chart and Bollinger band images, the method effectively captures structural patterns and volatility dynamics. The framework applies similarity metrics and Intersection over Union (IoU)-based visual comparison to identify historically similar patterns and generate intelligent trading signals without model training or complex parameter tuning. Experimental results demonstrate that combining visual features of candlestick …

Dendrimer Nanogels With Built-In Free Radical Scavenging Enable Efficient Topical Delivery Of A Hydrophilic Antioxidant To Restore Lens Redox Balance For Cataract Treatment, Lin Qi, Huari Kou, Anna Chernatynskaya, Da Huang, Vimalin Jeyalatha Mani, Humeyra Karacal, Nuran Ercal, Hu Yang

Chemistry Faculty Research & Creative Works

Cataract is a leading cause of vision impairment worldwide and are primarily caused by oxidative stress that damages and aggregates lens proteins, leading to lens opacification. However, the eye's anatomical barriers limit the penetration and bioavailability of antioxidant therapies. To address this challenge, a dendrimer-based nanogel with a built-in reactive oxygen species (ROS)-scavenging capability developed by us was employed to deliver the antioxidant N-acetylcysteine (NAC) to the lens. NAC was loaded into a generation-5 PEGylated poly(amidoamine) dendrimer (G5-PEG-TK, termed the GPT) nanogel. The resulting NAC-GPT was characterized for its ROS-scavenging activity, bioavailability, and corneal permeability. The efficacy of NAC-GPT was …

Electromyography, Prosthetic Properties, And Running Biomechanics In Recreationally Active Persons With Lower Extremity Amputation, Paige M. Agnew

Rehabilitation Sciences Theses & Dissertations

Lower extremity loss affects nearly 150,000 individuals in the United States yearly yielding extreme health care costs annually. Typically, prosthetic devices are prescribed for 5-8 years despite known changes to an individual’s gait as time progresses. Patients can expect to undergo approximately 8-12 weeks of gait retraining to improve their comfort and efficiency. Biomechanical changes occur when running with a specific running prosthetic including considerable biomechanical and neuromuscular interlimb asymmetries and alterations in loading patterns. The purpose of this dissertation was to investigate the biomechanical demands for lower extremity prosthesis users during running. The first study synthesized peer reviewed evidence …

Bioengineering The Future Of The Human Species: H+’S Ideological Iterations Of Trans-/Posthumanity As Exemplified By Futurist Literary Texts = (Bio)Technological Solutions For (And/Or) Reification Of Systemic Inequities?, Marjorie E. Bomhower

English Theses & Dissertations

While humanity has, throughout our species’ history, endeavored to dream and create astonishing, and ever-evolving, (bio)technologies with the utopian ideals of bettering our day-to day lives and achieving greater longevity, our endeavors have (thus far) not only produced remarkable, beneficial advances in longevity and quality of life, but have also yielded devastating and dire outcomes; often at the cost and victimization of marginalized communities. This dissertation focuses on select (bio)technologies – particularly, those promoted by H+ (the most current and popular technoutopianist non-profit, “educational,” organization) – with an investigation of current and nascent (bio)technological evolutions, futurist literary texts, and critical/digital …

Exploring Hemodynamic Signatures Using Event Camera, Zaid Ahmed

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis investigates event-based sensing for hemodynamic measurements in transmission mode through the human finger. Conventional frame-based imagers are limited by exposure time, frame rate, and motion blur, which reduce sensitivity to fast optical transients. To address these bottlenecks, this thesis introduces a novel transmission-mode sensing framework using a Prophesee EVK4 HD neuromorphic sensor. By capturing asynchronous ON/OFF events generated by local intensity changes, this work presents a new approach to three tasks: intra-finger pulse transit time (PTT) and pulse wave velocity (PWV) estimation, event-based transmission mode laser speckle contrast imaging (LSCI), and Flicker Spike Arrival Time (FSAT) Delay Mapping, …

Workforce Resilience In Public Transportation Agencies, Kristal D. Metro

Civil Engineering ETDs

A strong, resilient public workforce is necessary to keep the United States’ infrastructure system running smoothly. Across the public sector, hiring is lagging behind increasing retirement rates, leaving public agencies facing the loss of institutional knowledge at unprecedented levels. Combined with above-average retirement rates, low unemployment rates, and below-average salaries, workforce shortages are expected to become critical, putting the resilience of the public transportation workforce, and by extension, the United States public infrastructure and services at risk. The purpose of this research is to determine the best practices for recruiting and retaining employees at public transportation agencies, thereby positively influencing …

Design And Construction Of Prestressed Concrete Balanced Cantilever Bridges, Ahmed S. Elareshy, Ashraf M. Osman, Ismail. M. Kamal, Amr A. Abdelrahman

HBRC Journal

Balanced cantilever concrete bridges have recently been widely used in mid and long-span bridges. This paper presents a comprehensive review of the development and design of prestressed concrete balanced cantilever (PCBC) bridges, focusing on research related to real case studies of both precast and cast-in-place box-girder bridges investigated through finite element modeling (FEM) or field measurements. The research strategy targeted peer-reviewed journal articles, conference papers, and technical reports published over the last two decades in major engineering databases. Construction methods, design methodology, and structural behavior of this type of bridge are discussed, alongside key findings on long-term response, dynamic performance, …

Efficiency Comparison Of Reduced Graphene Oxide (Rgo) Composite-Incorporated Polyacrylonitrile Nanofibrous Filters For Respirable Crystalline Silica Dust And Coal Dust, Mahsa Moradi, Ashish Kakoria, Lina Zheng, Guang Xu

Mining Engineering Faculty Research & Creative Works

The health of miners working in underground mines is greatly threatened by their exposure to respirable crystalline silica (RCS) found in coal dust. While coal dust includes RCS, it is important to know the specific filtration efficiency for RCS particles compared to coal dust to improve protective measures. This study compares the filtration efficiency of reduced graphene oxide (rGO) composite-incorporated Polyacrylonitrile (PAN) nanofibrous filters at four different concentrations of rGO (0, 2, 6, and 10 wt.%) for RCS particles and coal dust. The filters were made using the electrospinning method. They were tested separately with RCS particles and coal dust …

Propagation And Interaction Of Gravity Currents Induced By Successive Release Of Two Lock Fluids, Khem Prasad Bhattarai, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study investigates the dynamics of sequentially released gravity currents in a lock-exchange configuration consisting of two lock fluids using high-resolution numerical simulations and compares them with the classical single-lock exchange. The results demonstrate that, in a two-lock-fluid configuration, the overtaking of the lighter lock current by the heavier lock current alters the current's front dynamics, leading to complex velocity transitions. Before overtaking occurs, the front propagation is slower than in the classical single-lock-fluid case because of lower density contrast, but after overtaking, the heavier lock fluid accumulates at the head region of the current and enhances its speed. The …

Community Engagement Through Robotics Mentoring – Unlv, First Nv, And High School Robotics Teams, Brendan O'Toole

Community Engagement Expo Research Posters

The UNLV Robotics Mentorship program includes a two-semester course that trains students to support local high school FIRST Robotics Competition (FRC) teams. ‘ME 464 Robotics Mentoring I’ provides training in design, mentoring,  fabrication, and programming. ‘ME 465 Robotics Mentoring II’, pairs students with local high school teams to serve as technical mentors for the competition season.

Voltage Breakdown Strength And Energy Density Of Ceramic Srtio₃ At Cryogenic Temperatures From 295 K To 77 K, Hung Trinh, Alan Devoe, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

The low-temperature dependence of the DC dielectric breakdown strength (EBD) and the energy storage density (W) of capacitors, fabricated from high purity polycrystalline strontium titanate, were investigated in the temperature range from 295 K to 77 K. Test samples were constructed with a process similar to that used for multilayer ceramic capacitors (MLCCs). The permittivity, loss tangent, leakage current, and breakdown strength were measured as a function of temperature and voltage. Weibull statistical analysis was used to quantify breakdown distributions. Despite electric-field suppression of permittivity, breakdown strength increased significantly with decreasing temperatures, leading to enhanced energy density. The breakdown field …

AiXGa1−XN (0.7 < X < 1) Schottky Diodes Using Distributed Polarization Doped Layer With A Current Density Of 14 Ka/Cm2, Tariq Jamil, Abdullah Al Mamun Mazumder, Mafruda Rahman, Muhammad Ali, Grigory Simin, M. Asif Khan

Faculty Publications

High Al-content Al_xGa_1-xN (0.7 < x < 1) quasi-vertical Schottky barrier diodes (SBDs) with distributed polarization doping were grown on the bulk AlN substrate. They exhibit excellent rectification behavior with a large forward current density (~14 kA/cm² ) and a high breakdown field of ~8.3 MV/cm. The SBDs also exhibited low ideality factors of (n~1.2) with a high Schottky barrier height (Φ _b~ 1.7 eV). Thus, this study demonstrates the feasibility of the distributed polarization doping approach for high current–high voltage devices.

Flaked Paraffin Wax-Based Thermally Enhanced Composite Phase Change Materials: Toward A Highly Efficient Thermally Responsive Temperature-Regulating Asphalt Pavement, Feng Ma, Meng Pang, Zhen Fu, Xinye Jiang, Qiang An, Yingjie Hou, Wenhao Dong, Jenny Liu, Jiasheng Dai

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

To mitigate high-temperature distress in asphalt pavements and enhance thermal regulation, flaked paraffin wax (FPW) was selected as the PCM and incorporated into asphalt. To prevent leakage, FPW was microencapsulated (FPW-MPCM). To boost thermal conductivity, FPW-MPCM was combined with expanded graphite (EG) via two methods: One method involves using EG as an adsorption carrier to prepare EG-adsorbed FPW phase change microcapsules (FPW-MPCM-EG); the other method uses EG as the core material to prepare FPW/EG graphite phase change microcapsules (FPW/EG-MPCM). These four PCMs were added to asphalt at 3 %, 6 %, 9 %, and 12 % (wt.%) to prepare phase-change …

Reconstruction Of Information System Acceptance Model In The Era Of Integrated Artificial Intelligence: A Systematic Literature Review, Ilham, Merlin Apriliyanti

Library Philosophy and Practice (e-journal)

This study aims to explain the rapid development of Artificial Intelligence (AI) which has driven significant transformations in the development and use of information systems. However, most classical information system acceptance models, such as the Technology Acceptance Model (TAM) and  (UTAUT), have not been able to fully explain the unique characteristics of AI-based systems that are autonomous, adaptive, and complex. This study aims to reconstruct the information system acceptance model in the era of integrated AI through a Systematic Literature Review (SLR) approach. This study was conducted using the PRISMA protocol on 130 leading scientific articles indexed by Scopus and …

The Waldo Dataset, Mary E. Koone, Rosie Kallie, Vassilis Athisos, Laurel S. Stvan

Computer Science and Engineering Datasets - Archive

Distinct from the task of predicting the author of a document (authorship attribution), we focus on addressing the issue of how to estimate the similarity between the written language styles of authors. To do so, we present a dataset of metadata derived by asking human annotators, who were presented with three documents, to identify which two were written by the same author and which was written by a different author. The dataset has over 400 such annotations, creating a companion to the Amazon Web Services (AWS) customer review dataset, laying the groundwork for crowdsourcing applications to other natural language processing …

Deep Learning Based Control System For Multi-Zone Hvac Residential Buildings, Mohammad H. Z. Alghalayeeni

Mechanical Engineering Theses

Heating, ventilation, and air conditioning (HVAC) systems are major contributors to residential energy consumption. However, most homes continue to rely on single zone thermostat control, which regulates temperature based on a single sensor and cannot account for thermal variations across multiple rooms. This often leads to uneven thermal conditions and inefficient energy use in multi-zone residential buildings. This thesis presents a deep reinforcement learning based approach for improving HVAC zoning control through dynamic airflow distribution. A physics based multi zone thermal model of a residential house was developed to simulate heat transfer processes including conduction, convection, solar and internal heat …

Virtual Humans In Virtual Reality: A Scoping Review On Sociability, Fidelity, And Expression, J K Sangeeth Chandran, Marisa Llorens Salvador, Cathy Ennis

Articles

Introduction:

Virtual reality (VR) systems have evolved significantly over the past decade, enabling immersive experiences with enhanced realism and interactivity. This has motivated an interest in socially oriented applications. As user proxies, Virtual Humans (VHs) play essential roles in such applications. However, despite technological advancements, achieving realistic, expressive, and socially responsive VHs continues to present design and implementation challenges. In this scoping review, we present the state-of-the-art of VR VHs, examining the impact of VHs on the user experience.

Methodology:

We reviewed 59 papers retrieved from five databases across three core themes: the implementation and impact of VH facial expressions, …

Mechanical Performance Of Equilateral Triangular Lattices: The Role Of Nodal Fillets, Fakhreddin Emami, Andrew J. Gross

Faculty Publications

Triangular lattices are widely employed for their high strength to weight ratios, yet their mechanical performance is sensitive to geometric features, particularly the nodal geometry. This study investigates the influence of nodal geometry on the mechanical behavior of equilateral triangular lattices across a broad range of relative densities using high fidelity finite element simulations. We characterize the elastic properties, and strength limits as functions of fillet radius. Our results confirm the expected trend that, in stretching-dominated lattices with low relative density, the introduction of fillets reduces both stiffness and buckling resistance. In contrast, at higher relative densities, filleted nodes can …

Electrochemical Sensors And Processes In Molten Salts: Chlorine Production, Electroanalytical Chemistry, And Thin-Layer Electrodes, Tyler Williams

Theses and Dissertations

Molten salt electrochemistry has historically played a substantial role in the metallurgical industry, and this trend is only accelerating in areas of green steel, direct ore processing, and rare-earth processing. In addition, the recent surge of interest in molten salt nuclear reactors has provided an additional application for molten salt electrochemical processes, including the reprocessing of used nuclear fuels and the development of electrochemical sensors for nuclear applications. In this work, the development of a chloride volatility separation process for used nuclear fuel is advanced; electroanalytical methods are improved for identifying and quantifying unknown analytes with and without the presence …

Photoplethysmography For Measuring Cognitive Load In Xr Environments: A Systematic Review, Alya Alshehhi, Qammer H. Abbasi, Rami Ghannam

School of Engineering Technology Faculty Publications

Photoplethysmography (PPG) is a low-cost, low-power biosensing technology with growing applications in education, particularly for monitoring cognitive load in eXtended Reality (XR) learning environments. Measuring cognitive load is critical for preventing overload and optimising immersive learning, yet existing approaches such as self-reports or Electroencephalography (EEG) are often intrusive, costly or impractical for real-time use. This systematic review is the first to synthesize a decade of research (2015–2025) on the use of PPG for cognitive load measurement in XR. Twenty-three studies were identified and analysed according to PRISMA guidelines, with attention to sensor placement, integration with other modalities, research design, and …

Arid: Agglomerative Regionalization Via Information Divergence, A Novel Clustering Algorithm For Geo-Spatial Data, Joshua David Sills

Dissertations and Theses

Regionalization is a clustering problem that seeks to partition geospatial data into geographically contiguous regions while remaining internally homogeneous in their attributes. It has been successfully applied towards the development of urban planning, natural resource discovery, and ecological analysis. Existing popular approaches optimize homogeneity using Euclidean or variance-based criteria, which ignore distributional differences such as variance shifts, multimodality, and higher-order dependence. This thesis introduces ARID (Agglomerative Regionalization via Information Divergence), a spatially constrained agglomerative clustering framework that replaces distance-based merging with an information-theoretic, Ward-like criterion that utilizes the Kullback-Leibler (KL) divergence. ARID constructs a neighborhood graph from coordinate space and …

Generalizing Networks To Address Data Imbalance For Facial Action Unit Recognition, Andrew W. Sumsion

Theses and Dissertations

Facial action unit (AU) recognition is used in a variety of downstream applications, including sign language translation, dementia detection, pain detection, and other high-impact tasks that require understanding facial motion. Although AU recognition is a well-established field, a number of unresolved issues remain. An initial problem is the need to improve overall performance on the benchmark datasets, as measured by the average F1 score. Also, the performance across all individual AUs, not just the average F1 score, needs to be increased. Recently, the field has shifted its attention towards ensuring that AU recognition models generalize beyond the distributions represented in …

Tusqh: Topological Control Of Volume-Fraction Meshes Near Small Features And Dirty Geometry, Brian Reese Shawcroft

Theses and Dissertations

This work develops a framework to create meshes with user-specified homology from potentially dirty geometry by coupling background grids, persistent homology, and a generalization of volume fractions. For a mesh with fixed grid size, the topology of the output mesh changes predictably and monotonically as its volume-fraction threshold decreases. Topological anti-aliasing methods are introduced to resolve pinch points and disconnected regions that are artifacts of user choice of grid size and orientation, making the output meshes suitable for downstream processes including analysis. The methodology is demonstrated on geographical, mechanical, and graphics models in two-dimensions (2D) and three-dimensions (3D) using a …

Impact Of Urban Roadway Work Zones On Road Users And Other Stakeholders, Lyndsey Renee Harris

Lyles School of Civil Engineering Graduate Student Reports

As urban populations continue to rise at an unprecedented rate, the need for highly maintained infrastructure in cities -- buildings, utilities, and transportation networks -- has become increasingly critical. An urban work zone refers to a designated area within a city where roadway construction, maintenance, or rehabilitation activities are taking place. These zones are typically characterized by high traffic volumes, complex roadway networks, and proximity to residential, institutional, and commercial land uses. Urban work zones often involve lane closures, detours, reduced speed limits, and temporary traffic control measures to ensure safety for road workers and road users. Due to the …

Wasting The Risk, Or Risking The Waste? Understanding The Trends Of Critical Raw Material Loss Into Waste Streams During Copper And Aluminium Processing, Ella Lausberg, Joël Brugger, Rahul Ram, John R. Owen, Deanna Kemp, Micheal S. Moats, Jonathan Hamisi, Vanessa N.L. Wong

Materials Science and Engineering Faculty Research & Creative Works

Many critical raw materials (CRM) necessary in the transition to carbon-neutral energy reside in the waste streams of mining projects, as they are by-products and often not recovered alongside the primary metal. This work aims to document (i) the loss and potential recovery of by-product metals during the host commodity processing and (ii) the consequences of non-recovery, via a multi-scale risk–reward analysis. The information on the deportment of by-product metals through processing circuits is crucial for treating them as a resource, without which they risk near-permanent loss when treated as 'waste'. We review the deportment of tellurium and selenium as …

Engineering 50 Years From Today: A Purdue Engineering Community Perspective, Arvind Raman

Purdue University Press Books

Since opening its doors in 1874, Purdue University’s College of Engineering and its graduates have been at the forefront of technological breakthroughs and are now poised to lead the next generation of engineers in the United States and around the globe. Featuring more than twenty-five essays from former Boilermakers, Engineering 50 Years From Today both celebrates the program’s 150th anniversary and looks ahead, exploring what the field of engineering might look like half a century from now. Leading luminaries from Purdue’s engineering community, including prominent university professors as well as innovators working in the private sector, reveal how technologies related …