Engineering Commons^™

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

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

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

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

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

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

McKelvey School of Engineering Graduate Student Theses & Dissertations

I_Ks (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 I_Ks 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

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

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

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 …

Interaction-Aware Safe Planning For Human-Robot And Multi-Robot Systems, Haoyi Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Robots operating in shared environments must interact safely not only with static obstacles but also with other decision-making agents, including humans and other robots. In such settings, both safety and task completion depend on the ability to reason about interaction. Two major challenges arise. In human-robot interaction, future human behavior depends on latent internal factors, such as attentiveness and behavioral style, that are not directly observable to the robot. In multi-robot systems, decentralized reactive navigation can fail in cluttered environments when reciprocal interactions create deadlocks that prevent progress through narrow passages or bottlenecks. This thesis investigates these two challenges from …

Temperature And Environmental Implications On Ti3c2cl2 Mxene Degradation Process, Yang Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

MXenes, a rapidly emerging class of two-dimensional transition metal carbides and nitrides, have attracted considerable attention owing to their exceptional electrical, mechanical, and chemical properties. However, the inherent thinness of their atomic structure and the reactivity of their functional groups render MXenes susceptible to environmental degradation, whereby the lattice integrity is compromised and desirable material functionalities are dimin- ished. In this work, ex situ electron microscopy characterisation is performed on Ti₃C₂Cl₂ MXene specimens subjected to controlled gas environments — nitrogen gas (N₂) and air — at annealing temperatures of 200°C and 600°C, with …

Evaluating Team Formation Strategies With Algorithms, Ethan E. Lopez, Andy Vo

Student Scholar Symposium Abstracts and Posters

Effective teamwork is essential for collaborative learning, yet forming compatible student groups remains a persistent challenge. This study explores how algorithmic team-building methods influence students’ social and academic compatibility overtime. To support this investigation, we designed a visual survey system called “The Disco Ball." Evaluating work ethics, lifestyles, behaviors, and communication styles, students were initially assigned to project teams using one of three conditions: (1) random assignment (control), (2) a “most matches” condition maximizing similarity between students, and (3) a “diverse communication styles” condition designed to balance differing interaction preferences. After an initial collaboration period, students were given the opportunity …

Coal Ash-Derived Aluminosilicate Precursors: A Chemical Engineering Approach To Geopolymer Characterization, Hafiz Abdul Basit, Abdullah Bashir, Abdur Raafey

World of Coal Ash Proceedings

The chemical and microstructural evaluation of coal-derived aluminosilicate precursors is critical for understanding their suitability in advanced construction material systems. In this study, a characterization of Class F fly ash, ground granulated blast furnace slag (GGBFS), and Silica Fumes (SF) was conducted to elucidate their morphological and elemental features. Scanning Electron Microscopy (SEM) was used to assess particle morphology and surface characteristics (porosity, particle diameter, particle geometry), and Energy-Dispersive X-ray Spectroscopy (EDS) to determine elemental composition and distribution. The analysis revealed distinct morphological and compositional differences among the precursors, including spherical fly ash particles, calcium-rich slag phases, and ultra-fine silica …

State Permitting Program Update, Jessica Reiss

World of Coal Ash Proceedings

State Permitting Program Update Jessica L. Reiss, Barnes & Thornburg LLP, 11 South Meridian Street, Indianapolis, IN 46204 KEYWORDS: states, permitting, permit program, rulemaking ABSTRACT At the end of 2016, the United States Congress authorized states to establish permit programs for coal combustion residuals (CCR) surface impoundments and landfills.[1] Since then, several states have established such programs, and the United States Environmental Protection Agency (U.S. EPA) has approved programs for Oklahoma,[2] Georgia,[3] Texas,[4] and North Dakota,[5] proposed approval for Wyoming,[6] and denied approval for Alabama.[7] Other states, such as Indiana,[8] are actively working through the state rulemaking process and plan …

Zero-Waste And High-Value Valorization Of Coal Combustion Residues Via Critical Minerals Recovery And Cementitious Materials Production, Hongyan Ma

World of Coal Ash Proceedings

Coal combustion residues (CCRs) pose significant environmental and disposal challenges, yet they also represent an untapped resource rich in aluminosilicates and critical minerals. This work presents a zero-waste, high-value valorization pathway that integrates critical mineral recovery with the production of cementitious materials. Advanced separation and extraction techniques are employed to recover strategically important elements such as gallium and rare earths, while the mineral-rich residues are simultaneously processed into supplementary cementitious materials (SCMs) for blended cements and concretes. This integrated approach not only offsets the environmental burden of CCR disposal but also supports domestic supply chains of critical minerals and reduces …

Revolutionizing Closure Systems: The Performance Advantages Of Structured Geomembranes, Scott Perugia

World of Coal Ash Proceedings

Coal combustion residual (CCR) containment facilities have traditionally been closed using methods that have changed little over several decades, but structured geomembranes are now reshaping closure design by improving slope stability, increasing interface friction, enhancing drainage, and providing long-term durability. Two systems are emerging as leading solutions: a structured geomembrane paired with a geotextile and vegetative cover, and a structured geomembrane paired with engineered turf. This presentation compares these approaches using field performance data, laboratory testing, and lessons learned, with emphasis on key factors such as infiltration control, drainage efficiency, slope stability, constructability, and regulatory compliance. The engineered turf system …

Developing Concentrated Brines / Salt Slurries For Disposal Of Coal Ash Wastewaters., Lance Edling

World of Coal Ash Proceedings

If coal ash wastewater is not fully concentrated to the greatest extent possible, then this results in greater disposal volumes and costs. However, concentrating a wastewater stream high in scaling compounds can be difficult. Membranes are prone to scale and Vacom thermal systems are higher in operating cost. This presentation will discuss the need to minimize disposal volumes by concentrating wastewater that is readily prone to scale and foul. The discussion will present past project examples of waste streams that were concentrated until salt crystals formed and the method used to minimize fouling and scaling during the concentration process. In …

Recinis™ Wet Beneficiation Process For Landfilled Coal Ash, Tim Sambrook

World of Coal Ash Proceedings

The decline of coal-fired power generation has reduced fresh “Run-of-Station” ash availability, increasing reliance on reclaimed ash from landfills to meet supplementary cementitious material (SCM) demand. This shift has lowered OPC replacement rates and raised concrete costs due to inconsistent ash quality. ReCinis™ offers a low-capex wet beneficiation solution for landfill-aged, saturated, and variable-quality coal ash. With over 5 billion tons of ash impounded in the U.S., this process enables long-term supply security where dry beneficiation is unsuitable. Combining proven mineral processing techniques with coal ash expertise, ReCinis™ can be deployed as a 150,000 tpa skid-mounted plant or scaled to …

Lessons Learned From A Full-Scale Discrete In-Situ Stabilization Project For Ccr Impoundment Closure, Tony Moran, Paul Jennings, Jacob Susser, Tim Silar

World of Coal Ash Proceedings

ENTACT, in collaboration with Silar Services, Inc., the patent holder of Discrete In-Situ Solidification (DISS) technology, has successfully performed a full-scale implementation of DISS in a Coal Combustion Residual (CCR) impoundment. DISS hydraulically isolates ash from surrounding groundwater by constructing a low-permeability barrier at the impoundment bottom to treat a layer of ash and tying into underlying natural soil layers. DISS enables targeted stabilization within a designated treatment zone, minimizing the disturbance of overburden compared to traditional excavation methods and reducing the use of costly cementitious reagents. The process starts with Reagentless Drilling of the overburden CCR utilizing a specialized …

From Clogs To Compliance: Overcoming Persistent Leachate Head Issues In Ccr Landfills, Breanne Kahnk, Zachary Bauman

World of Coal Ash Proceedings

State and federal regulations require that landfills, including coal combustion residual (CCR) landfills, be designed and operated to maintain leachate head levels of less than 30 centimeters (approximately 1 foot). While proper leachate collection system design and routine maintenance are critical for meeting this requirement, challenges such as clogging of drainage media, pipes, fittings and/or pipeline perforations, settlement of collection pipes, and breaks in the piping system can lead to elevated leachate levels, posing risks to compliance and long-term system performance. TRC will provide an overview of leachate collection system regulatory requirements along with design, operation, and maintenance strategies that …

Plasma Coal Ash Processing For Enhanced Recovery Of Rare Earth Elements & Precious Metals: Proven From R&D To Commercial Plants, George Paskalov, Victoria Campbell, Jason Honigberg

World of Coal Ash Proceedings

Our Radio-frequency Plasma System is an ash pretreatment before the application of extractive metallurgy and addresses current elemental, methodological, and technological limitations of complex and refractory coal ash. Our system data shows from 10-20% improved recovery, to 9x-100x. RFP can access all metals contained in coal ash. Our focus is not on the alteration of established methodologies, such as cyanidation for non-refractory ore, which has a proven return and capacity to achieve target revenue at-scale. Using the RFP systems, no waste is created, overburden can be more easily dealt with, and no metal content will be left behind. We assert …

Probing The Critical Element Chemistry Of Coal-Combustion Fly Ash: Electron Microbeam Investigations Of The Spent Ash From The Pilot-Scale Acid Extraction Of Rare Earth Elements From A Beneficiated Kentucky Fly Ash, James Hower

World of Coal Ash Proceedings

Fly ash derived from the combustion of an eastern Kentucky high volatile bituminous coal blend was beneficiated to yield a <75-μm product with a reduction in the carbon and spinels and reacted with a strong acid in a pilot-scale unit to extract rare earth elements. Electron microscopy showed a wide range of rare earth-bearing minerals. The acid-extracted fly ash had a rim that was depleted in REE and in most other elements except silicon.

Standardization Of Coal Ash Testing, Classification, And Harvesting, Benjamin Gallagher, Chris Frishcosy, Eric Hageman

World of Coal Ash Proceedings

Standards such as product specifications, test methods, practices and guides play a crucial role in supporting both commerce and science. Standardization helps build consistency and reliability whether it pertains to the performance of an ingredient in a product or in the measurement of a material characteristic. Coal combustion products, such as coal ash and synthetic gypsum, exhibit unique characteristics and many standard have been developed to characterize these materials and support their beneficial use. ASTM is a voluntary, consensus-based organization, and publishes many standards related to coal combustion products. Currently, there are seven ASTM standards related to chemical analysis of …

Leachate Quantification And Reduction – One Facility’S Path To Zld, Cedric Ruhl

World of Coal Ash Proceedings

The Environmental Protection Agency (EPA) promulgated Effluent Limitation Guidelines (ELG) that govern liquids discharged from energy production facilities. According to the ELG, energy production facilities that burn coal beyond December 31, 2034 must convert to a Zero Liquid Discharge (ZLD) system by December 31, 2029*. This presentation focuses on one coal-burning facility’s strategy to meet ZLD requirements. The predominant source of liquid that will be treated by the proposed ZLD system is leachate from an active coal combustion residual (CCR) landfill. Is the ZLD’s design capacity suitable for average leachate flow conditions? Is there enough leachate storage volume to manage …

Ai-Guided Upcycling Of Coal Combustion Residues In Blended Cement And Concrete, Hongyan Ma

World of Coal Ash Proceedings

Coal combustion residues (CCRs), including fly ash, bottom ash, desulfurization gypsum, etc., on specification or off-specification, remain an abundant yet underutilized byproduct of power generation. While these materials have long been considered as supplementary cementitious materials (SCMs), their variable chemical and physical characteristics limit broader adoption in blended cement and concrete. This study introduces an AI-guided framework to accelerate the upcycling of CCRs into high-performance construction materials. By integrating materials informatics, machine learning models, and experimental validation, the framework enables rapid property prediction and performance-based preprocessing recommendation or mix design optimization for diverse CCR sources. Preliminary results demonstrate the ability …

Comparison Of Residuals From Neighboring Power Stations With Different Coal Combustion Technologies, Allan Kolker, Denise Levitan, Brett Valentine

World of Coal Ash Proceedings

Due to the ongoing need for critical minerals, coal combustion residuals (CCR), like fly ash, have been evaluated as a potential source of critical minerals, particularly rare earth elements (REEs). Previous studies have found that REEs in fly ash are largely contained within aluminosilicate glass from which they are difficult to extract. However, these studies have predominantly studied CCR from conventional pulverized coal fired (PCF) plants. PCF plants use higher temperatures (≥1300°C) than do circulating fluidized-bed (CFB) plants (~900-950°C). Samples of feed coal, fly ash, and bottom ash were collected from two adjacent Vietnamese coal-fired power stations, one with a …

Impacts Of Updating Background Groundwater Statistics For Ccr Compliance, May Raad, Molly Reeves

World of Coal Ash Proceedings

In 2017, many power utilities adopted statistical methods to comply with the EPA’s Coal Combustion Residuals (CCR) Rule under the Hazardous and Solid Waste Management System. By 2017–2018, most owners completed initial statistical evaluations for detection and assessment monitoring to meet CCR deadlines. Groundwater sampling and analysis requirements in Parts 257.95, 257.98, and 257.102 are critical for compliance, yet implementation is complex. Subsections 257.93(f) and (g) lack clarity on which statistical tests to apply or how to address distributions and outliers. Additionally, the Rule does not specify when or how to update background threshold values (BTVs), though EPA’s Unified Guidance …

Advancing Ccr Site Management With Rapidly Deployable Gccm Technology For Runoff And Drainage Control, Nathan Ivy

World of Coal Ash Proceedings

GCCM’s were first invented over 20 years ago. These products combine both a concrete – hard armor – top surface for protection and durability and a geomembrane bottom surface for lower permeability. Originally used for erosion control, smaller drainage channel and remediation projects, this presentation discusses the newest iteration in GCCM technology. This product incorporates a 12 mil LLDPE backing which allows for thermal bonding and significant reduction in seepage at the joints. It can be used in a wide variety of applications from drainage ditches and swales to water and wastewater conveyance along with slope protection and erosion control …

Ccr 2026: The Plot Thickens—Your Complete Guide To What’S Next, Mark Rokoff

World of Coal Ash Proceedings

The landscape of CCR management is poised for significant transformation with the proposed EPA regulation introduced in early 2026. This presentation will provide a clear and enhanced summary of the key points in the proposed rule, highlighting the significant changes and implications for the industry. Where appropriate, it will be further enhanced by benchmarking data to compliment the key points and the effect to the “CCR Universe”. The proposed regulation aims to adjust the requirements for effective CCR management, introducing new compliance measures and timelines that will impact owner/operators across the board. Key discussion points will include: • Summary of …