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Harvesting Rare Earths From Coal Ash Using An Ionic Liquid, Laura Stoy May 2026

Harvesting Rare Earths From Coal Ash Using An Ionic Liquid, Laura Stoy

World of Coal Ash Proceedings

This presentation highlights a promising early-stage pathway for transforming coal fly ash from a long-term liability into a source of both critical minerals and construction materials. The speaker describes a recyclable ionic-liquid process that, at bench scale, demonstrates selective recovery of rare earth elements (REEs) from a wide range of U.S. fly ashes under mild conditions while preserving the treated solids for potential use as supplementary cementitious materials (SCMs). Attendees gain insight into why this chemistry is attracting attention: it avoids full acid digestion, shows strong preference for REEs over bulk metals, and enables repeated solvent reuse in a closed …


Testing Of Accelerated Pozzolanic Activity Of Fly Ash, Anne Oberlink, Tom Robl, Bob Jewell, Haley Johnson May 2026

Testing Of Accelerated Pozzolanic Activity Of Fly Ash, Anne Oberlink, Tom Robl, Bob Jewell, Haley Johnson

World of Coal Ash Proceedings

The determination of the pozzolanic reaction in fly ash by ASTM strength activity index has been shown to be problematic, frequently producing false positives. The use of Wenner probe resistivity has been demonstrated to be rapid, simple and non-destructive method, producing no false positives. However, using this method and confirming it with other techniques finds that the reaction itself is slow with a dilatancy of 28 days or more before the measurements become discriminatory, a major drawback to this method. This study used high-temperature, high humidity curing of OPC-based mortars with various fly ash sources to determine how pozzolanic activity …


Innovative Analysis Of Groundwater Data For Scalable, Defensible, And Predictive Compliance, Shannon Zahuranec May 2026

Innovative Analysis Of Groundwater Data For Scalable, Defensible, And Predictive Compliance, Shannon Zahuranec

World of Coal Ash Proceedings

Groundwater monitoring networks at coal combustion residual (CCR) facilities now yield dataset volumes that routinely exceed the capacity of traditional, univariate interpretation. This presentation introduces a scalable multivariate and machine learning (ML) framework that prioritizes understanding data structure before predictive models are applied. The workflow applies Principal Component Analysis and other multivariate statistics to groundwater datasets, to illustrate how unsupervised learning can rapidly reveal dominant sources and controls on impacted and unimpacted groundwater quality. The talk frames multivariate analysis as a practical portfolio management tool, emphasizing inference categories rather than concentrations or site identifiers. Fleet-scale multivariate screening offers strategic advantages …


Subsurface Delineation Of Coal Combustion Residuals Using Multiple Geophysical Methods, Eric Hageman, Adam Rak, Thomas Jordan, Kate Mckinley May 2026

Subsurface Delineation Of Coal Combustion Residuals Using Multiple Geophysical Methods, Eric Hageman, Adam Rak, Thomas Jordan, Kate Mckinley

World of Coal Ash Proceedings

Geophysical techniques provide alternative methods of Coal Combustion Residual (CCR) delineation and characterization to supplement more invasive boring programs used for beneficial reuse planning. A demonstration project was designed to characterize the electromagnetic and seismic stratigraphy of CCR material and test the effectiveness of three geophysical techniques: Electrical Resistivity Imaging (ERI), Transient Electromagnetic (TEM) induction, and Multi-channel Analysis of Surface Wave (MASW). The demonstration project was completed at a dry-stack CCR unit containing a variety of CCR ash, gypsum, and thin layers of drainage aggregate (limestone). During a single-day deployment, several geophysical survey tests were conducted in specific areas of …


Geopolymers For Construction And Mining: Material Characterization And Application Prospects, Radoslaw Pomykala, Gabriela Fuks May 2026

Geopolymers For Construction And Mining: Material Characterization And Application Prospects, Radoslaw Pomykala, Gabriela Fuks

World of Coal Ash Proceedings

Geopolymers have long been presented as an alternative to conventional concretes and cement-based binders, yet their practical use remains limited for various reasons. This paper examines both the material properties of such mixtures and their potential for broader application.

The study evaluated geopolymers produced from different types of fly ash, including typical siliceous ashes and ash with elevated CaO content. The influence of mixture components, such as solids content, activator type, and sample preparation and curing methods, on technological properties was investigated. Research covered fresh mixtures—rheological behavior and setting time—as well as hardened samples using mechanical testing, XRD, and SEM. …


Riki&Dolphin: Real Time Data Transmission From The Bottom Of A Cave To A Website, Luca Tringali, Giacomo Canciani Dr., Tecla Tripari, Alexander Debenjak, Caterina Bearzotti May 2026

Riki&Dolphin: Real Time Data Transmission From The Bottom Of A Cave To A Website, Luca Tringali, Giacomo Canciani Dr., Tecla Tripari, Alexander Debenjak, Caterina Bearzotti

International Journal of Speleology

Coming from over 10 years of experience in cave monitoring in northeast Italy, Gruppo Speleologico Talpe del Carso, has designed Riki and Dolphin: customizable, low cost, and easy to assemble tools for getting real time data transmission from the bottom of a cave, even underwater, to a webserver. Their use has been tested to monitor air temperature inside the Abisso Bonetti Cave (Classical Karst, Italy), proving for the first time that a cave in Gorizian Karst can systematically be colder than the outdoor temperature even in winter, recording an internal temperature even lower than 0°C. The Dolphin device can be …


Evolution Of Instrumentation Use For Ccr Unit Decision Making, Nick Mcclung, Victoria Bierwirth, Matt Bishop May 2026

Evolution Of Instrumentation Use For Ccr Unit Decision Making, Nick Mcclung, Victoria Bierwirth, Matt Bishop

World of Coal Ash Proceedings

Over the past decades, the power industry’s instrumentation needs and requirements have shifted to meet industry standards and regulations. In the early 2010s, piezometers and slope inclinometers were the primary types of instrumentation used to evaluate the stability of a CCR Unit. Some of the piezometers and slope inclinometers installed are still in use today to evaluate long-term stability for operations and closure. Since this time, additional instrument types were selected for installation including observation wells and temporary wells to further understand phreatic conditions within the CCR Unit. As utilities are faced with closures including removal of free liquids, data …


Evaluating The Properties Of Ohio Ponded Fly Ash For Reliable Use In Concrete Mixtures, Ayah Suliman May 2026

Evaluating The Properties Of Ohio Ponded Fly Ash For Reliable Use In Concrete Mixtures, Ayah Suliman

World of Coal Ash Proceedings

Concrete producers are under pressure to reduce the carbon footprint of concrete while maintaining a reliable supply of supplementary cementitious materials. Meanwhile, U.S. coal production in 2023 declined to less than half of its 2008 peak, significantly reducing the availability of fresh ASTM C618 compliant fly ash. At the same time Ohio contains more than 145 million cubic yards of coal combustion residuals stored in ponds, representing a large and underutilized source of potential fly ash for concrete applications. This study evaluates the suitability of harvested Ohio ponded fly ash for use in concrete through practical and specification-driven testing aligned …


Benefits Of Geophysical Imaging For Coal Combustion Residuals Management Unit Delineation, Gabriel Herbert May 2026

Benefits Of Geophysical Imaging For Coal Combustion Residuals Management Unit Delineation, Gabriel Herbert

World of Coal Ash Proceedings

Gabriel J. Hebert1, Gregory B. Byer1, Margaret Gentile1 1Arcadis U.S., Inc., 2839 Paces Ferry Road SE, Suite 1000, Atlanta, GA 30339 KEYWORDS: geophysical imaging, delineation, CCRMU ABSTRACT Under the 2024 Legacy CCR Rule detailed in 40 CFR Part 257, Section 75, all electric utility companies with a known legacy coal combustion residuals (CCR) surface impoundment are required to conduct a facility evaluation to identify the location, dimensions, and volumes of CCR placed and remaining on site and to assess structural stability. At a minimum, the presence or absence of CCR management units (CCRMUs) must be documented through a desktop records …


Extracting Rees From Refuse Pile Coal, Howard Mcclintic May 2026

Extracting Rees From Refuse Pile Coal, Howard Mcclintic

World of Coal Ash Proceedings

Concurrent Technologies Corporation (CTC) has a patented high temperature electric arc furnace (EAF) technology that reaches 4000-degree centigrade temperature(s). Such high temperatures are sufficient to extract each of the seventeen rare earth elements (REEs) from coal fly ash to ultimately manufacture diverse magnets. Neodymium iron boron magnets (NdFeB) are the strongest magnets produced, heretofore almost exclusively by the Chinese. For national security reasons, CTC has become part of the domestic supply chain, as an alternate to China. Scaling is the next hurdle, since our demonstration unit is operational. Nationwide, coal is decreasingly used as a fuel for generating electricity. However, …


Basin Ash Harvesting At The Brunner Island Station, Kyle Flynn May 2026

Basin Ash Harvesting At The Brunner Island Station, Kyle Flynn

World of Coal Ash Proceedings

Tribo-electrostatic separation has been used for the commercial beneficiation of coal combustion fly ash to produce a low carbon product for use as a cement replacement in concrete for over twenty-five years. With 24 separators in 18 coal-fired power plants and cement plants across the world, ST Equipment & Technology LLC’s (STET) patented electrostatic separator has been used to produce over 25 million tons of low carbon product that has been recycled for use in concrete or cement production. STET has developed and commercialized a new process for beneficiation of reclaimed fly ash from landfills and ponds that utilizes fly …


Adaptive Design And Execution In Ccr Pond Closure: A Case Study Of Technical And Regulatory Innovation, Jay Mokotoff, Angie Casbon-Scheller May 2026

Adaptive Design And Execution In Ccr Pond Closure: A Case Study Of Technical And Regulatory Innovation, Jay Mokotoff, Angie Casbon-Scheller

World of Coal Ash Proceedings

Closure by removal (CbR) of CCR impoundments presents complex challenges, particularly when unique hydrogeologic conditions exist. This presentation highlights the advance planning and ongoing closure of a Midwestern utility’s East Ash Pond (EAP), a relatively small facility with highly atypical characteristics. To comply with the CCR Rule, sluicing to the EAP ceased while the generating unit remained operational. Fly ash handling was converted to a dry system for beneficial reuse; however, wet sluicing of bottom ash continued. To avoid constructing a new regulated CCR impoundment, an innovative geotextile tube containment area (GTCA) was designed and implemented to capture bottom ash …


Recycling 3d Printing Waste In The Binghamton University Makerlab, Kevin Tejera May 2026

Recycling 3d Printing Waste In The Binghamton University Makerlab, Kevin Tejera

Library Research Scholars Program Spring 2026

3D printing is an important part of many university makerspaces. However, it comes with negative environmental consequences, including polylactic acid (PLA) filament waste. Currently, the MakerLab at Binghamton University has no closed-loop recycling system, leading to large quantities of used filament being sent to landfills, where it contributes to greenhouse gases and microplastic production.

This research project looks at the feasibility of an in-house PLA filament recycling program by examining the mechanical recycling process, cost/equipment needs, contamination issues, available space, and the effect of repeated recycling on the filament. An economic analysis will be completed through a break-even analysis and …


Phytomining Potential Of Native Rocky Mountain Plants, Halle Cogley May 2026

Phytomining Potential Of Native Rocky Mountain Plants, Halle Cogley

Honors Theses

Standard mining practices of the past have left valuable, critical minerals remaining within mine waste and tailings piles. Phytoremediation, or the use of plants to uptake and store heavy metals, has grown in popularity for these sites. A new technology, phytomining, is being developed that not only offers the benefits of phytoremediation but also allows a new pathway to extract and generate revenue from these untouched critical minerals. Certain plants have been identified as hyperaccumulators with the ability to bioaccumulate a high level of certain minerals in their plant tissue. This study explored different species of native plants within the …


Collector Blends For The Flotation Of Rare Earth Silicates, Padmore Fosu Amankwah May 2026

Collector Blends For The Flotation Of Rare Earth Silicates, Padmore Fosu Amankwah

Honors Theses

Rare earth elements (REEs) are critical for modern technologies, but their extraction from minerals remains challenging due to various factors, and their impact on mineral bonding and resulting crystal structure. Fundamental studies have shown that the concentration of rare earth minerals (REMs), such as rare earth silicates (RES), depends on factors such as Lanthanide contraction (LC), Coordination Number (NC), and silicate polymerization (SP). These influence flotation responses pending silicate type (e.g., sorosilicates, phylosilicates, nesosilicates, inosilicates, orthosilicates, etc.). To better understand this behavior and optimize REE recovery, samples from Halleck Creek, an American Rare Earth property in Wyoming, were obtained. Characterization …


A Systems Perspective On Workstation Ergonomic Principles And Their Application In Emergency Care Environments, James Espinosa, Alan Lucerna May 2026

A Systems Perspective On Workstation Ergonomic Principles And Their Application In Emergency Care Environments, James Espinosa, Alan Lucerna

Rowan-Virtua Research Day

Background: Workstation ergonomic principles are commonly included in mandatory healthcare training programs. These recommendations—monitor height relative to eye level, neutral arm positioning, and adjustable seating—derive largely from occupational ergonomics literature designed to reduce musculoskeletal strain and improve comfort during computer work. Emergency Departments (EDs), however, represent dynamic environments with shared workstations and workflow interruptions that may influence the implementation of these recommendations.

Objective: To summarize the evidence supporting commonly taught workstation ergonomic principles and frame them within a systems perspective of ED work environments.

Methods: Narrative review of occupational ergonomics guidelines, ergonomic intervention studies, and human factors literature relevant to …


Optimization Of Refolding, Purification, And Analytical Characterization Of Proinsulin(F25d) Soluble Antigen Array Immunotherapy, Abigail Richardson May 2026

Optimization Of Refolding, Purification, And Analytical Characterization Of Proinsulin(F25d) Soluble Antigen Array Immunotherapy, Abigail Richardson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Type 1 Diabetes (T1D) is characterized by autoreactive immune responses to insulin and its precursor, proinsulin. Soluble antigen arrays (SAgAs) displaying the metabolically inactive proinsulin variant, proinsulin(F25D), represent a promising antigen‑specific immunotherapy candidate for T1D. However, the production of these platforms is hindered by substantial practical challenges, including protein aggregation, inefficient refolding, and the lack of sensitive analytical tools to verify quality and dosage. This work establishes an integrated, scalable pipeline for the purification, conjugation, and quantification of a proinsulin(F25D) SAgA. First, we optimized the refolding of recombinant methionine-proinsulin(F25D) (M-PI(F25D)) from inclusion bodies using controlled buffer systems and created a …


Hybird Vtol Gust Load Alleviation Uav, Ryan Birch, Mouhamadou Diop, Sebastian J. Flores, Alan Alan Rubio-Saavedra May 2026

Hybird Vtol Gust Load Alleviation Uav, Ryan Birch, Mouhamadou Diop, Sebastian J. Flores, Alan Alan Rubio-Saavedra

Senior Design Project For Engineers

Here's a 250-word abstract:

Abstract

This paper presents the conceptual and preliminary design of a sub-500g hybrid vertical takeoff and landing (VTOL) fixed-wing unmanned aerial vehicle (UAV) equipped with an active gust load alleviation (GLA) system. The aircraft combines passive twist wingtip (PTWT) devices with an inertial measurement unit (IMU)-based adaptive feedforward control architecture to reduce peak wing-root bending moments by 30–40% relative to an unmitigated baseline configuration.

The propulsion system employs a twin tilt-rotor plus rear pusher arrangement within an 80g mass budget, enabling clean sensor inflow while supporting both hover and efficient cruise flight at 12–13 m/s. Electronic …


Lunar Manufacturing Systems And The Role Of Additive Recycling Technologies, Camille A. Newman May 2026

Lunar Manufacturing Systems And The Role Of Additive Recycling Technologies, Camille A. Newman

Honors Theses

Renewed international interest in sustained lunar exploration has created a growing demand for technologies to support long-duration space exploration. Part of the recent Artemis missions and the Moon to Mars initiative is to improve key mission capabilities and fill critical gaps necessary to sustain lunar habitation. Waste management, recycling systems, and manufacturing systems have been identified as critical technologies that need further development before a sustained mission is possible. This thesis explores the feasibility of an additive manufacturing and recycling system designed to process plastic waste generated during extended lunar habitation. Initial research focused on existing manufacturing and recycling technologies …


Engagement Modeling And Inference For Risk-Aware Path Planning Under Adversarial Uncertainty, Grant Stagg May 2026

Engagement Modeling And Inference For Risk-Aware Path Planning Under Adversarial Uncertainty, Grant Stagg

Theses and Dissertations

This dissertation develops methods for planning safe and efficient trajectories for autonomous vehicles operating in environments containing adversarial and environmental threats with uncertain parameters. The central objective is to quantify and control the risk of adverse events--such as interception or detection--when threat characteristics are imperfectly known. To address this challenge, probabilistic weapon engagement zone (PEZ) models are introduced to estimate the likelihood of violating adversarial engagement constraints under uncertainty in pursuer state and capabilities. Multiple computational strategies are developed for PEZ evaluation, including first-order sensitivity-based approximations, Monte Carlo estimation, and neural-network surrogate models. These approaches enable rapid engagement-probability assessment and …


Integrated Solar And Regenerative Braking System For Off-Grid Charging Of An Electric Motorcycle, Christian Soolany, Dhimas Oki Permata Aji, Sigit Suwarto, Setya Permana Sutisna, Furqon Furqon May 2026

Integrated Solar And Regenerative Braking System For Off-Grid Charging Of An Electric Motorcycle, Christian Soolany, Dhimas Oki Permata Aji, Sigit Suwarto, Setya Permana Sutisna, Furqon Furqon

Journal of Mechanical Engineering Science and Technology (JMEST)

This study introduces an off-grid charging system developed for a modified 110 cc electric motorcycle. The system incorporates a portable photovoltaic (PV) array and a regenerative braking feature, aimed at improving the motorcycle's energy efficiency. The setup includes a 72 V, 20 Ah lithium-ion battery, a 240 Wp portable PV array, and a 2 kW Brushless DC (BLDC) motor with regenerative braking to enhance the energy available on board. From the experiments, the vehicle demonstrated an average energy consumption of 44.9 Wh/km and achieved a range of about 32 km per charge. The PV system generated between 200 and 270 …


A Remote Sensing Approach To Identifying Zones Of Instability In Mine Tailings Impoundments Using Multi-Sensor Satellite Data, Arden K. Pierce May 2026

A Remote Sensing Approach To Identifying Zones Of Instability In Mine Tailings Impoundments Using Multi-Sensor Satellite Data, Arden K. Pierce

Honors Theses

Mine tailings impoundments are structures built to contain the chemical and sedimentary byproducts generated by ore extraction activities. In this common method of mining waste storage, the tailings can be pumped into containment ponds and held behind earthen embankments to prevent the release of hazardous substances into the surrounding environment. Monitoring environmental factors that influence the structural integrity of these impoundments is essential for identifying areas vulnerable to instability and failure. Soil moisture is a factor that can affect the stability of mine tailings impoundment structures. This study evaluates the relationship between satellite-derived soil moisture and surface deformation at mine …


Lunar Manufacturing Systems And The Role Of Additive Recycling Technologies, Camille A. Newman May 2026

Lunar Manufacturing Systems And The Role Of Additive Recycling Technologies, Camille A. Newman

Honors Theses

Renewed international interest in sustained lunar exploration has created a growing demand for technologies to support long-duration space exploration. Part of the recent Artemis missions and the Moon to Mars initiative is to improve key mission capabilities and fill critical gaps necessary to sustain lunar habitation. Waste management, recycling systems, and manufacturing systems have been identified as critical technologies that need further development before a sustained mission is possible. This thesis explores the feasibility of an additive manufacturing and recycling system designed to process plastic waste generated during extended lunar habitation. Initial research focused on existing manufacturing and recycling technologies …


Monitoring Groundwater Flow At Old Works Using Anisotropy, 3-D Electrical Geophysics, And Dem-Based Terrain Analysis, Yihaun Gao May 2026

Monitoring Groundwater Flow At Old Works Using Anisotropy, 3-D Electrical Geophysics, And Dem-Based Terrain Analysis, Yihaun Gao

Honors Theses

Groundwater flow in shallow heterogeneous environments is often difficult to characterize using a single geophysical method. This study applies an integrated approach combining azimuthal resistivity anisotropy, self-potential (SP) measurements, DEM-derived terrain indices, and three-dimensional electrical resistivity tomography (3-D ERT) to delineate preferential groundwater pathways at the Old Works Golf Course in Anaconda, Montana. Azimuthal anisotropy analysis from eighteen 2-D ERT profiles revealed a dominant directional dependence in electrical conductivity, indicating a structural or sedimentological control on subsurface flow. The anisotropy results indicate a preferred conductivity direction of approximately 200°–210° in azimuth (0° is north), suggesting that groundwater movement is guided …


Rf Properties Of Military Radio Enclosures, Ethan Messner May 2026

Rf Properties Of Military Radio Enclosures, Ethan Messner

Honors Theses

Ghost radios are used in a MANET setup by the 11th Airborne Division during operations in Alaska, however, the Ghost radios are limited by battery life and extreme cold temperatures. This work investigates the effects of different enclosures on the propagation characteristics of the Ghost radio. A testing setup was created to measure the S-parameters of a 2-port network in an open field to quantify the impact the enclosures will have on antenna gain. A finite element model of the final enclosure design was created in ANSYS HFSS to determine the effectiveness of adding an attachment onto the enclosure to …


Phytoextraction Potential Of Willows (Salix Spp.) For Common Heavy Metal Contaminants., Johannes Chandler May 2026

Phytoextraction Potential Of Willows (Salix Spp.) For Common Heavy Metal Contaminants., Johannes Chandler

Honors Theses

Phytoextraction is a method for removal and recovery of heavy metals from contaminated substrates using plants. There is a growing need to test, identify, and further understand species effective for phytoextraction to feasibly remove and recover heavy metals. In this study, the phytoextraction capacity of Willow (Salix) species was tested for metal contaminated soils and waters from legacy mining in Butte, Montana. The willows were grown in a hydroponic system in two 8-week long growth trials, employing a 2x2 factorial design of contaminated soil, clay beads, contaminated mine water and uncontaminated water as the media. Heavy metal concentrations (Mn, Zn, …


Voltage-Sensor–Targeting Modulators Of Iks: Identifying Critical Functional Groups Of C28 Via Electrophysiology And Sar Modeling, Jiacheng Huang May 2026

Voltage-Sensor–Targeting Modulators Of Iks: Identifying Critical Functional Groups Of C28 Via Electrophysiology And Sar Modeling, Jiacheng Huang

McKelvey School of Engineering Graduate Student Theses & Dissertations

IKs (KCNQ1/KCNE1) channels are essential for cardiac repolarization, and their dysfunction contributes to arrhythmogenic disorders such as Long QT Syndrome type 1 (LQT1). Pharmacological activation of IKs has therefore emerged as a promising therapeutic strategy. C28, a recently identified voltage-sensor–targeting activator, has been shown to markedly shift KCNQ1/KCNE1 voltage dependence and enhance current amplitude, validating the voltage-sensing domain (VSD) as a druggable site. However, the structural determinants that underlie C28’s activity remain incompletely understood. In this study, we aimed to identify critical functional groups of C28 by screening a structurally diverse set of C28-like analogs and evaluating their …


Toward Vehicle-Agnostic Driving Signatures For Cognitive Impairment Prediction From Naturalistic Driving Data, Aadarsha Gopala Reddy May 2026

Toward Vehicle-Agnostic Driving Signatures For Cognitive Impairment Prediction From Naturalistic Driving Data, Aadarsha Gopala Reddy

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis studies whether naturalistic driving data can help predict binary Clinical Dementia Rating (CDR) status while accounting for differences across vehicles. The final analytic dataset comprised 26,968 participant-weeks from 304 participants. Weekly driving features were derived from real-world telematics data and combined with four demographic covariates. Primary model comparisons used leave-one-participant-out (LOGO) cross-validation, with one individual held out at a time and pooled participant-level metrics used as the main reporting surface.

The main comparison includes six model families evaluated on the same dataset under a shared LOGO framework. Performance remained modest overall. GRU-DANN had the highest participant-level ROC AUC …


Largest 2-Regular Subgraphs In Complete S-Partite Graphs, Yiyang Jiang May 2026

Largest 2-Regular Subgraphs In Complete S-Partite Graphs, Yiyang Jiang

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, we focus on the class of complete $S$-partite graphs, for $S$ an undirected graph possibly with self-loops, and address the problem of finding largest $2$-regular subgraphs of these graphs, which can be formulated as an integer linear program. Roughly speaking, a complete $S$-partite graph is obtained by replacing every single node of $S$ with a number of nodes, preserving the edge/non-edge relations of $S$. Our motivation in studying largest $2$-regular subgraphs is rooted in the structural systems theory, particularly in the problem of finding largest subnetworks that can sustain controllability or asymptotic stability of the corresponding subsystems. …


Improving Semantic Precision In Text-To-Image Diffusion Models Via Latent-Space Optimization And Semantically-Parsed Evaluation, Mohammad Rouie Miab May 2026

Improving Semantic Precision In Text-To-Image Diffusion Models Via Latent-Space Optimization And Semantically-Parsed Evaluation, Mohammad Rouie Miab

McKelvey School of Engineering Graduate Student Theses & Dissertations

Text-to-image diffusion models can produce visually impressive images from natural-language prompts, but they often fail to satisfy the detailed semantic constraints expressed in compositional prompts. Typical failure modes include omitted objects, merged entities, incorrect quantities, incorrect attribute binding, and leakage of one entity's attributes onto another. This thesis studies the problem of semantic precision in text-to-image generation: how faithfully a generated image satisfies the structured meaning of its prompt.   The thesis makes two linked contributions. First, it presents a training-free inference-time refinement method for diffusion-based image generation. The method operates directly in latent space during denoising and uses noun-phrase-aware cross-attention …