Digital Commons Network^™

Effect Of Rheology Modification On Fiber Orientation And Dispersion In 3d-Printed Ultra-High-Performance Concrete, Haodao Li, Alfred Addai-Nimoh, Seongho Han, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The extrusion process in 3D concrete printing (3DCP) facilitates horizontal alignment of steel fibers along the printing direction, thus enhancing the load-bearing capacity of printed elements. However, such shear-induced fiber alignment is highly sensitive to rheological properties. This study investigates how variations in dynamic yield stress (τd) and plastic viscosity (μ), influence the extrudability, fiber orientation and dispersion, and anisotropic mechanical behavior of ultra-high-performance concrete (UHPC). Five viscosity-modifying agent (VMA) types were incorporated at two content levels to modify the rheology of printable UHPC. Results showed that moderate VMA additions improved printability, whereas excessive contents markedly increased τd and μ; …

Reframing Soil Freezing As An Unsaturated Process, Antai Dong, Xiong Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Soil freezing and frost heave are inherently unsaturated soil phenomena. However, most existing numerical models are based on saturated soil mechanics or assume full saturation. This simplification introduces conceptual inconsistencies, requires modifications that violate fundamentals in soil mechanics and fluid mechanics, and often leads to the use of self-conflicting soil properties. To overcome these limitations, this study develops a physically consistent, fully coupled thermohydraulic model for soil freezing grounded in modern unsaturated soil mechanics. A soil freezing characteristic surface (SFCS) is introduced to represent unfrozen water content in partially frozen soils as a function of both suction and temperature. Recognizing …

High-Throughput Characterization Of Creep In Additively Manufactured 316l Stainless Steel, Raushan Kumar Singh

All Graduate Theses and Dissertations, Fall 2023 to Present

Advanced materials are widely used in industries such as nuclear energy, aerospace, and automotive engineering, where components are exposed to extreme temperatures and stresses over long periods of time. As new materials continue to emerge, researchers need efficient ways to evaluate their mechanical performance so they can be used safely and effectively. Among several mechanical challenges, creep is a major concern in these conditions. Creep is a type of mechanical failure in which materials gradually deform when exposed to high temperatures and constant load. Conventional methods for evaluating creep typically involve testing a single specimen at a time, which can …

Time-Frequency Analysis Of Arterial Pulse Signals Of Cardiovascular Disease Patients Measured By A Microfluidic-Based Tactile Sensor, Md Mahfuzur Rahman

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents a single-degree-of-freedom (SDOF) based time–frequency analysis framework that can simultaneously extract a comprehensive set of cardiovascular autonomic indices from arterial pulse wave recordings obtained at rest and post-exercise, supporting non-invasive monitoring of autonomic recovery during cardiac rehabilitation. The framework rests on three technical contributions.

First, an SDOF analytical model of motion artefacts quantifies two physically distinct distortion mechanisms: additive baseline drift and Time-Varying System Parameter (TVSP) generated distortion of the Tissue-Contact-Sensor (TCS) stack. Baseline drift is slowly varying and removable by filtering; TVSP distortion rides on all harmonics of the true pulse signal and cannot be removed …

Evaluation Of Ostomy Pouching Change Practices Among Hospital-Based And Community-Based Nurses, Hannah Gerlach

All Theses

An estimated 725,000 to 1 million Americans are living with an ostomy and depend on ostomy pouching systems as part of their daily care. Effective ostomy management requires regular pouch changes and consistent skin care to prevent peristomal skin complications. Many individuals living with an ostomy face long-term challenges in managing their ostomy care, which can negatively affect their health-related quality of life. There is a need to understand how professional experience across different care environments, such as hospital-based and community-based settings, influences ostomy nursing care practices.

This study evaluates how nurses working in hospital-based settings and community-based settings perform …

Developing A Rapid Urban Forest Assessment System For Sustainable City Greenification, Daniel Gonzalez

Master's Theses

This thesis presents the Rapid Urban Forest Assessment (RUFA) system, a web-based platform that integrates urban tree inventories and aerial tree detection to assess forest health across California’s census-designated places. RUFA combines inventoried tree records with coordinates detected from high-resolution multispectral imagery using convolutional neural networks, then computes a composite RUFA Score from four metrics: canopy cover percentage, trees per capita, tree diversity (TD-50), and tree evenness. The thesis addresses two engineering challenges in building the dashboard: querying and aggregating over seven million tree records in real time, and rendering spatial summaries at multiple zoom levels without recomputing cluster assignments …

Optimal Management Of Electric Vehicle Fast Charging Stations Via Lyapunov Optimization And Reinforcement Learning, Mohammad Hossein Abbasi

All Dissertations

The transportation sector is responsible for 28% of global energy-related emissions, with road transport accounting for most of these emissions. While electric vehicles (EVs) are essential for decarbonizing transportation, widespread adoption depends on fast, efficient charging. Fast charging reduces charging time but accelerates battery degradation, whereas slow charging increases range anxiety. In addition, fast charging stations (FCSs) impose significant stress on distribution grids, making their operation a critical challenge. Optimizing FCS operation can conflict with EV fast-charging objectives, yet existing research largely treats these problems independently despite their strong interdependence.

Current fast-charging methods focus on individual cells or small battery …

Human-Centered Design Of Extended Reality For Learning Adoption, Effectiveness, And Collaborative Training Performance, Bhargav Upadhyay

All Dissertations

Extended reality (XR) technologies like virtual reality (VR) and augmented reality (AR) can be used for technical training to help students learn and practice complex tasks in a safe digital environment. Despite known benefits evidence is required to explore the effectiveness of these technologies to support student learning outcomes. Furthermore, technical training programs need evidence about when these tools improve learning, what are the barriers to adoption of these technologies, and how training should be designed by leveraging these technologies. This dissertation examined how XR technologies can support higher education and workforce training, specifically focusing on barriers and facilitators to …

A Hybrid Vsm-Des Approach For Bottleneck Identification And Reduction In A Continous One-Piece Flow Assembly System, Ana Sofia Rey Nevarez

Open Access Theses & Dissertations

Identifying bottlenecks in a production line is rarely as easy as pointing to the slowest station and assuming that's where the problem is. The real question is which stations moves the system when you change them. Lean manufacturing has been one of the initiatives that major companies in the U.S. have been trying to adopt to remain competitive. This thesis aims to understand the results of applying a combination of a Discrete-Event Simulation (DES) with a Value Stream Mapping (VSM), to find the bottleneck of a continuous one-piece flow assembly line of a tier-1 power management manufacturer from the El …

Green Pathways For Phytic Acid Extraction From Agriculture Residue For Flame-Retardant Applications, Laura Fronchetti Guidugli

Theses and Dissertations

The increasing generation of agricultural residues and the growing demand for sustainable chemicals and materials have intensified the interest in valorization of biomass-derived resources within a circular economy setting. Wheat bran, a major by-product of the cereal processing industry, accounting for approximately 14-30% of the wheat grain, represents an abundant and underutilized feedstock rich in phytic acid (PA, IP6), a phosphorus-containing biomolecule with applications in the food preservation, antioxidant, and flame-retardant sectors. However, conventional phytic acid recovery methods rely heavily on acid-assisted extraction processes that generate significant waste streams and environmental burdens. Therefore, the objective of this dissertation was to …

Balancing War And Peace In Taekwondo Athlete Development: A Multi-Criteria Coaching Decision Support Framework Using Leadership Scale For Sports And Fuzzy Ahp, King Harold A. Recto, Hazel Jade L. Antonio, Jhyrald Anthony P. Dalida

Electronics, Computer, and Communications Engineering Faculty Publications

Coaching effectiveness is frequently evaluated through competitive outcomes, with the assumption that coaching behaviors directly influence athlete performance. This study examined the relationship between perceived coaching behaviors and individual win percentage among collegiate Taekwondo athletes using the Leadership Scale for Sports (LSS). Descriptive statistics, correlation analysis, and regression analysis were conducted across five coaching dimensions: Training and Instruction, Democratic Behavior, Autocratic Behavior, Social Support, and Positive Feedback. Results showed that none of the coaching dimensions demonstrated a statistically significant relationship with win percentage. Although coaching behaviors did not significantly predict win percentage, the findings suggest that athlete development is shaped …

Wind Effects Induced By Multivortex Tornadoes On A Low-Rise Building, Yi Zhao, Guirong Yan, Tetsuya Takemi, John Van De Lindt

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Multivortex tornadoes contain two or more subvortices that orbit within a parent vortex and can generate highly intermittent and localized near-ground wind fields. This study investigates how tornado flow structure affects wind effects on a low-rise building using large-eddy simulations. One single-vortex tornado and three multivortex tornadoes with different subvortex configurations are examined by systematically varying swirl ratio. Tornado translation is modeled using a relative-motion framework in which the building traverses the vortex field. Aerodynamic force and moment coefficients are evaluated along the traversing path. Additional stationary simulations are conducted to examine repeated load amplification associated with subvortex passages. Compared …

Toward Risk-Informed Design Of Supercooling Heat Exchangers: Statistical Inference And Experimental Investigation Of Heterogeneous Ice Nucleation, Daniel B. Gardner

All Graduate Theses and Dissertations, Fall 2023 to Present

Ice-based cooling storage systems can reduce electricity costs and grid strain by making ice during off-peak hours and using it for air conditioning during the day. One promising design works by chilling water below its freezing point as it flows through a heat exchanger, then allowing it to freeze in a separate storage tank. The challenge is that the chilled water can freeze prematurely inside the heat exchanger itself, blocking the flow and shutting the system down. Preventing this unwanted freezing requires understanding how and where ice begins to form on surfaces, a process called nucleation.

This dissertation investigates ice …

Multistage Integrated Systems For Wastewater Treatment And Resource Recovery: A Systematic Process Design Framework, Mahsa Golmohammadi, Ensiyeh Taheri, Ratish Ramyad Permala, Sebastien Allard, Mehdi Khiadani, Amir Razmjou

Research outputs 2022 to 2026

The wastewater treatment paradigm is shifting from pollutant removal toward integrated systems that simultaneously achieve contaminant treatment and resource recovery. Despite extensive literature on individual technologies, systematic frameworks for designing multistage integrated wastewater treatment and resource recovery systems remain notably absent. This review addresses this gap by developing a comprehensive decision framework that guides designers from influent characterization through technology selection across pretreatment, main process, and post-treatment stages. The framework accommodates diverse integration strategies, ranging from fully unified treatment processes to stage-specific configurations where each treatment stage employs technologies tailored to its designated function. Rather than optimizing for a single …

Validation Of A Portable Electrochemical Sensor For Real-Time Soil Nitrate Monitoring In Cotton Rhizosphere, Mohammad Solaiman, Elvis D. Sangmen, Ali Reza Galib, Tushar C. Sarker, Anil C. Somenahally, Shawana Tabassum

Electrical Engineering Faculty Publications and Presentations

Soil nitrate (NO3) exhibits rapid spatial and temporal variability that conventional point-sampling methods cannot effectively capture, limiting timely nutrient management and plant stress detection. This study aimed to validate a low-cost, threedimensional- printed electrochemical NO3 sensor for continuous in-soil monitoring and to evaluate whether sensor-derived NO3 dynamics reflect plant physiological responses. For this purpose, cotton (Gossypium hirsutum L.) plants were grown in pots under greenhouse conditions. The sensor was evaluated in two sequential phases: an initial calibration phase to characterize sensor response across a broad NO3 concentration range, followed by a validation phase in the cotton plant rhizosphere. In the …

Genwriter 2.0: A Hybrid Case-Based And Llm Rewriting Approach For Mitigating Implicit Gender Cues In Text, Shweta Soundararajan, Sarah Jane Delany

Conference papers

Gendered language is the use of words or phrases that indicate an individual's gender. Although useful in some contexts, gendered language can reinforce gender stereotypes and introduce bias, particularly in machine learning models for tasks involving people such as recruitment or occupation classification. When textual content about individuals, such as biographies, contain gender cues, models can learn spurious associations between gender and other characteristics of individuals, such as profession, potentially resulting in unfair outcomes such as reduced hiring opportunities for women.

To address this challenge, we propose GenWriter 2.0, a hybrid approach that integrates Case-Based Reasoning (CBR) with Large …

Practical On-Device Intelligence For Resource-Constrained Embedded And Wearable Devices, Xiao Ma

Dissertations and Theses Collection (Open Access)

Embedded and wearable devices increasingly rely on deep neural networks to support intelligent sensing applications directly on the device. However, building practical on-device intelligence remains challenging throughout the deployment lifecycle. Before deployment, models must remain accurate despite severe memory, computation, and energy budgets, and a single device often needs to support multiple sensing applications without deploying a separate model for each application. After deployment, the device continues to operate in changing real-world environments, where shifts in data distribution can degrade the model’s performance over time, so the model must be able to adapt to such shifts efficiently.

The first challenge …

Water-Heated Maisotsenko Cycle Humidifiers: A Component-Level Study On Evaporation And Exit Brine Concentration, Omar Abdulfattah Farag Omar A. Farag

Renewable Mechanical Energy

Maisotsenko-cycle (M-cycle) Heat-and-Mass Exchangers (HMXs) are usually assessed as part of complete cooling or desalination systems, which makes the behaviour of the humidifier itself difficult to distinguish. Here, a validated model is used to examine a water-heated M-cycle humidifier as an independent component. Inlet saline-water temperature, ambient temperature, Relative Humidity (RH), and water-to-air Mass-flow Ratio (MR) were varied, and performance was described by Water Evaporation Rate (WER), outlet-air specific humidity, and outlet brine salinity. Water heating and a larger MR produced the strongest increase in moisture addition because they maintained a warmer water film and greater transfer potential. At fixed …

A Review Of The Safety Alert Systems In Commercial Vehicles: Implementation Challenges And Trends For Electronic Logic Devices And In-Cab Alerts, Md Sadman Islam, Deep Patel, Ahmed Sajid Hasan, Mohammad Jalayer, Abdul S. Ngereza, Emmanuel Kidando

Civil and Environmental Engineering Faculty Publications

The trucking industry is crucial to the US economy, accounting for 73.1% of the value, 71.1% of the cargo, and 42.0% of the ton-miles of all commodities transported nationwide. Despite its pivotal role, the industry is affected by high crash rates, with truck crashes resulting in 5,472 fatalities in 2023 alone. These incidents not only exhibit a higher fatality rate per vehicle mile compared with passenger cars but also cause substantial economic disruptions. Predominantly, these crashes are attributed to the failure to stop or slow down because of insufficient sight distances. In recent years, trucking companies have implemented various technologies, …

Functionalized Loblolly Pine Derived Ultraporous Activated Hydrochars For Efficient Carbon Capture, Swarna Saha

Theses and Dissertations

The increasing concentration of anthropogenic carbon dioxide (CO₂) emissions has intensified the demand for efficient and sustainable carbon capture technologies. This dissertation investigates the development of functionalized ultraporous activated hydrochars derived from loblolly pine through hydrothermal carbonization (HTC) followed by chemical activation for enhanced CO₂ capture applications. Different functionalization strategies, including deep eutectic solvent (DES) modification, zeolite-assisted HTC, palladium-assisted HTC, and CO₂-assisted HTC, were systematically explored to evaluate the influence of pore structure, surface chemistry, and adsorption energetics on CO₂ capture performance. The synthesized materials were characterized using BET, FTIR, XRD, TGA, SEM, and adsorption isotherm modeling to establish the …

Five-State Seismic Damage Classification Of Steel-Girder Bridges On Soft Soil Using Directional Intensity Measures And Multi-Parameter Damage Indices, Ibrahim Alomari, Woubishet Zewdu Taffese, Mohammad Hossein Afsharmovahed, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Rapid yet accurate post-earthquake damage assessment of highway bridges is essential to ensure transportation network resilience. Traditional inspection, fragility analysis, and finite element modeling are time-consuming or inaccurate for real-time decision-making. This study compares ten machine-learning classifiers for the seismic damage states of highway steel-girder bridges that incorporate directional intensity measures to represent the variance of ground motions. Based on the nonlinear time-history analyses of two Missouri bridges, one Michigan bridge, and one Wisconsin bridge, multi-parameter structural damage indices were proposed and mapped to five damage states from none to collapse. Among ten supervised algorithms studied, the artificial neural network …

Field Calibration Of Flow Over Tilting Weirs In Canals, Joseph E. Pugh, Timothy K. Gates, S. Karan Venayagamoorthy, Caner Kutlu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Tilting weirs are widely used to regulate water levels in open channel irrigation systems and can also provide flow measurement capability that helps optimize irrigation efficiency and ensure equitable water distribution. This case study demonstrates adaptation of lab-based tilting weir ratings to field settings, where flow behavior is more complex. We compile and analyze an extensive data set derived from independent studies of five structures within three canal systems, featuring both lined and unlined channels with discharge ranging from 0.35 to 15 m3/s (12 to 530 ft3/s). Results indicate that lab-based rating equations can be calibrated to account for site-specific …

Barrier-Drainage Performance Of A Wicking Geotextile In Controlling Capillary Rise In Silt: Experimental Evaluation, Dahao Zou, Yipeng Guo, Jiejin Chen, Yafeng Li, Xiong Zhang, Yongjie Zhang, Luqiang Ding

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Capillary rise in silt significantly degrades its strength and durability, yet the hydraulic mechanisms governing moisture control using wicking geotextile in silt remain insufficiently understood. This study investigates the barrier-drainage performance of a wicking geotextile in silt through one-dimensional column experiments, supported by preliminary trials. Three configurations were examined: a control specimen without geotextile (CS), an embedded configuration (ES), and a surface-exposed configuration (SES). Volumetric moisture content and matric suction were monitored, capillary responses at the soil-geotextile interface and water storage behavior were evaluated. The results show that the wicking geotextile initially acts as a temporary capillary barrier due to …

Impact Of Climate Change On Extreme Windstorms And Implications For Structural Design In The United States, Teng Wu, Reda Snaiki, Frank Lombardo, Sihan Li, Michele Barbato, Guirong Yan, Robert J. Trapp

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Climate change impacts various extreme windstorms associated with specific meteorological phenomena in different ways. Because various windstorms contribute to the design wind speeds, this study systematically reviewed the state-of-the-art understanding of climate change effects on wind events that collectively contribute to structural wind design in North America, particularly the US, including extratropical cyclones (as well as nor'easters), tropical cyclones, thunderstorms, and tornadoes. For each windstorm type, the general evidence of climate change impacts on storm activities (e.g., occurrence frequency and intensity) are summarized, followed by the introduction of existing simulation frameworks for yearly (or subyearly) maximum storm winds under changing …

A Transfer-Learning And Continuous Optimization-Based Framework For Predicting Heat Treatment-Dependent Mechanical Properties Of Ded-Processed Low-Alloy Steels, Atiqur Rahman, Sung Heng Wu, Ranjit Joy, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Directed energy deposition (DED) of low-alloy steels involves strongly coupled effects among alloy composition, solidification behavior, and post-deposition heat treatment, making mechanical property prediction difficult when target-domain data are limited. This study develops a transfer-learning and continuous optimization framework for predicting heat treatment-dependent yield strength (YS), ultimate tensile strength (UTS), hardness (HV), and as-solidified phase fractions of martensite, ferrite, and austenite in DED-processed low-alloy steels. A CALPHAD-based dataset was generated for 125 low-alloy steel compositions. A multilayer perceptron (MLP) surrogate was first trained as a baseline model, then fine-tuned through transfer learning and progressively updated as staged continuous optimization; the …

A Laboratory Investigation Of Energy Dissipators At Embankment Dams, Nathan L. Young

All Graduate Theses and Dissertations, Fall 2023 to Present

Dams play a critical role in protecting communities from flooding and providing reliable water supplies. When large amounts of water pass through a dam’s spillway during floods, the discharge can travel at high speeds and carry potentially destructive kinetic energy that can damage the dam or erode downstream channels if that energy is not properly controlled. To reduce this risk, engineers commonly use hydraulic structures called energy dissipators that slow spillway discharge and safely release it downstream.

Commonly used energy dissipators at embankment dams include stilling basins that rely on a hydraulic jump – a sudden rise in water depth …

Nanostructured Negative Electron Affinity Gallium Arsenide Photocathodes With Enhanced Quantum Efficiency And Extended Charge Lifetime For Advanced Photoinjectors, Md Aziz Ar Rahman

Physics Theses & Dissertations

This dissertation presents a comprehensive experimental and computational investigation of nanostructured negative electron affinity (NEA) gallium arsenide (GaAs) photocathodes. This work was undertaken to achieve higher quantum efficiency (QE) and longer charge lifetime than conventional flat NEA GaAs electron sources commonly used in photoinjectors. Finite-Difference Time-Domain and charge-transport simulations of three types of nanostructure geometries reveal substantial QE enhancement over flat GaAs via Mie resonance mode excitation. Consequently, the truncated nanocone array (TNCA) photocathodes with heights of 400, 700, and 1000 nm were fabricated and NEA activated via Cs-NF₃ deposition. In a low-voltage ultra-high vacuum chamber with a base pressure …

Decarbonizing The C3 Splitter: Performance Optimization And Environmental Impact Of Mvr Integration, Dalia A. Ali Associate Prof.

Chemical Engineering

Due to the relatively low volatility (α) of propane and propene components, their separation is one of the most energy-intensive processes in the petrochemical industry. This study evaluates the technical, environmental and thermodynamic performance of a mechanical vapor recompression (MVR) heat pump integrated into a C3 splitter, compared to a conventional steam-heated distillation column. A sensitivity study was conducted using Aspen Plus software at different pressures, reflux ratios (RR) and at turndown operations. According to the results, the MVR system uses a compressor to raise the overhead vapor pressure to 38.7 bar to operate the heater without the need for …

From Screening To Risk: Assessment Of Potentially Toxic Elements In Children's Toys Along The El Paso, Tx, U.S.A.-Ciudad Juarez, Chih, Mex Border Region, Jesus Rodriguez-Loya

Open Access Theses & Dissertations

Children are uniquely vulnerable to potentially toxic elements (PTEs), absorbing them more readily than adults and encountering them through the hand-to-mouth behaviors of early childhood. Exposure carries element-specific consequences: lead (Pb) impairs cognitive development with no established safe threshold; cadmium (Cd) damages the kidneys and reduces bone mineralization; arsenic (As) is a recognized carcinogen and developmental neurotoxicant; hexavalent chromium (Cr) is carcinogenic and induces allergic dermatitis; nickel (Ni) is the leading cause of allergic contact dermatitis in children; and excess zinc (Zn) disrupts copper absorption and causes gastrointestinal distress. Toys are a distinctive source of such exposure, yet none had …

Investigating The Impacts Of Information Framing And Representation On Multi-Stakeholder Decision-Making For Tradespace Exploration, Meredith G. Sutton

All Dissertations

Tradespace exploration (TSE) is a decision-making process used in engineering design to search through a tradespace, containing all potential solutions to a design problem and their performance evaluations, in order to select optimal or near-optimal solutions. Solution optimality is driven by a desire to maximize the overall utility of a solution, which often cannot be done without making tradeoffs or compromises. The TSE process requires vast amounts of information which can be difficult to generate and understand, often leading to challenges including information overload, delays in decision-making, and suboptimal decisions, even for the most experienced designers. To address the challenges …