Engineering Commons^™

Electrochemically Active Liquid Organic Hydrogen Carriers For Energy Generation And Storage, Jinyao Tang

Theses and Dissertations

The growing demand for sustainable energy has spurred interest in hydrogen as a clean energy carrier, yet its widespread adoption is limited by storage and transport challenges. Liquid organic hydrogen carriers (LOHCs) offer a promising solution by enabling reversible hydrogen storage through chemical redox reactions under ambient conditions. Compared to conventional thermal methods, LOHC electrochemistry provides improved energy efficiency, operational safety, and integration into electrochemical systems. However, key challenges remain, such as catalyst deactivation, limited redox reversibility, and low system-level performance that hinder broader application. Alcohols like isopropanol (IPA) and cyclohexanol (CHOL), and amines like ethylamine, have emerged as promising …

Database Development For Reliable Small Object Detection In Maritime Environments, Jacob Matthew Whisenant

Theses and Dissertations

Achieving high reliability in small object detection is critical for advancing maritime and littoral intelligent navigation operations. Computer vision provides an undetectable form of perception that can be easily integrated into existing camera systems, offering a low-profile yet powerful solution for navigation and situational awareness in water-based environments. While deep learning techniques have significantly advanced the field of computer vision, the detection of small objects remains a persistent challenge. Limited pixel representation, the scarcity of large-scale small object datasets, and the reduced detail and indistinct features of small objects complicate detection efforts, especially in complex environments. These factors collectively hinder …

Saw Biosensor For The Detection Of Cyanobacteria And Cyanotoxin, Tally Bovender

Theses and Dissertations

The growing prevalence of cyanobacterial blooms and associated cyanotoxins, such as microcystin-LR (MC-LR), presents a significant threat to water quality and public health. Conventional detection methods, including ELISA and PCR, are often time-consuming, expensive, and require trained personnel, limiting their application in field settings. Hence, a miniaturized, quick testing sensor is proposed to circumvent the current sensing challenges for real time, in-situ diagnostics of MC-LR. The proposed high-frequency ultrasonic sensor employs surface acoustic waves (SAW). The sensor was designed using a multi-physics simulation tool to understand wave propagation in the piezoelectric substrate (lithium tantalate) and optimize the design of the …

Design Of Supercritical Reactors To Understand Supercritical Water Oxidation Process And Hydrothermal Flames, Victor Dubceac

Theses and Dissertations

Supercritical water oxidation (SCWO) has been a topic of immense interest as an effective technique/tool for hazardous aqueous waste disposal. SCWO can be achieved by introducing an oxidizer (e.g., H2O2), or a hydrothermal flame as an internal source of both heat and oxidizer species in an aqueous environment at conditions above the critical point of water (P > 218 atm and T > 647 K). SCWO poses important environmental advantages for the treatment of harmful organic materials contained in waste streams. An SCWO reactor has the potential to be compact in design and therefore can be an ideal alternative to existing technology …

Optical And Thermal Characterization Of Vertically Conducting Β-Ga₂O₃ Diodes Grown On 4h-Sic Substrates For Short-Wavelength (<254 Nm) Detection, Muhammad Hassan Tahir

Theses and Dissertations

The advancement of compact, thermally stable, and efficient devices for deepultraviolet (DUV) detection below 254 nm is critical for solar-blind sensing, radiation monitoring, and high-power electronics. This thesis presents the growth, fabrication, and detailed optical and thermal characterization of vertically conducting β-gallium oxide (βGa₂O₃) Schottky barrier diodes (SBDs) grown on n-type 4H-Silicon Carbide (4H-SiC) substrates using metal-organic chemical vapor deposition (MOCVD).

β-Ga₂O₃ is an ultra-wide bandgap (UWBG) semiconductor (~4.8 eV) with intrinsic DUV transparency and high breakdown electric field, making it an ideal candidate for short-wavelength photodetection. However, its low thermal conductivity limits its vertical device performance. To overcome this, …

Effect Of Growth Conditions On The Performance Of Vertically Conducting Beta-Ga2o3 Diodes On 4h-Sic Substrate By Mocvd, Nifat Jahan Nipa

Theses and Dissertations

This thesis highlights the critical influence of doping strategies, specifically co-delta doping with silicon (Si) and indium (In), on improving the structural quality and device performance of β-Ga₂O₃-based Schottky barrier diodes (SBDs). To achieve better thermal management, β-Ga₂O₃ thin film was grown on bulk 4H-SiC substrates using the Metal-Organic Chemical Vapor Deposition (MOCVD) technique, renowned for its precise control over composition, thickness and doping profile. The ultra-wide bandgap (UWBG), high critical breakdown field and low turn-on resistance of β-Ga₂O₃ make it a strong candidate for next-generation power electronics and short-wavelength detection in extreme environments. However, the presence of structural defects …

Characterizing The Relationships Between Cranial Geometry, Brain Morphometry, And Brain Mechanical Properties Using Mr Imaging And Elastography, Jessica Restivo

Theses and Dissertations

Traumatic brain injury (TBI) is a global health concern, with over 69 million cases annually. TBI risk depends on subject-specific neuroanatomical variation, yet research often only considers generic finite element (FE) models, based on the geometry and material composition of a 50th percentile male head. Although highly accurate, subject-specific models require expensive magnetic resonance (MR) imaging, elastography, and time-consuming computational resources. There is a need to create subject-specific TBI models that account for subject-specific variations, without neuroimaging. This study aims to create mathematical models to predict brain morphometry (dimensions, volume) [Objective 1] and mechanical properties (shear stiffness, damping ratio, octahedral …

Addressing Key Challenges In Mhz Power Converters, Aqarib Hussain

Theses and Dissertations

Power electronics are essential in applications such as aerospace, electric vehicles, and electric ships where compact, efficient, and high power-density converters are increasingly demanded. This push toward miniaturization has led to converter designs operating at switching frequencies in the megahertz (MHz) range. Higher-frequency operation enables significant reductions in passive component sizes—particularly transformers and inductors—thereby facilitating dense packaging. However, these benefits come with new challenges, including increased thermal stress, complex semiconductor behavior, higher-frequency magnetic design constraints, and elevated electromagnetic interference (EMI).

This research addresses several key challenges in MHz converter design. The first part involves the development of a 1-MHz, 1-kW …

Self-Regulated Thermal Management With Shape-Memory Alloy Torsional Tubes, Paula Sanjuan Espejo

Doctoral Dissertations and Master's Theses

The need for dynamic thermal management that adapts to varying system needs and requirements is a growing topic of interest in different engineering disciplines, most prominently aerospace and electronics. This demand for improved thermal management systems comes from the general increase of system efficiencies leading to an increase in component energy density. Shape-memory alloy actuators, which respond with a mechanical shape recovery to variations in temperature, can be used as self-regulated thermal management actuators that are able to respond to environmental thermal changes autonomously. In this dissertation, modeling and experimental analysis of a two-way shape-memory effect trained SMA torsional tube …

Embeddable Multi-Material Wireless Micro-Sensors Utilizing Additive Manufacturing And Enhanced Microstructure, Nicholas Reed

Doctoral Dissertations and Master's Theses

The development of embeddable, multi-material wireless microsensors offers transformative potential for structural health monitoring (SHM) in aerospace applications. This work integrates additive manufacturing (AM) techniques with advanced microstructural design to produce flexible, high-resolution sensors that can be directly embedded into polymer substrates. By utilizing the vat photopolymerization process, customized embedded sensors are seamlessly integrated into polymer AM structures. These sensors are then continuously refined, targeting increases in performance, both internal and external. Microstructural enhancements are explored to modify the rheological properties of the fabricated embedded sensing channels and enhance the adhesive bonding between the embedded sensor and the AM structure. …

Mtu-Llm: Llm-Based Multi-Robot Task Allocation And Path Planning For Heterogeneous Robots In Search And Rescue Operations, Kaushik Kannan, Jungyun Bae

Michigan Tech Publications

Urban Search and Rescue operations after natural disasters involve locating and assisting victims in hazardous environments, which is challenging. Classical Multi-Robot Task Allocation (MRTA) and path planning approaches have been used to deploy heterogeneous robot teams in unsafe areas. However, existing methods often lack focus on workload balance and requirement fulfillment and struggle to generalize across different scenarios. To address these challenges, we propose Multi-robot Task allocation Utilizing LLMs (MTU-LLM), a framework designed to reduce the development time for task allocation and path planning approaches, enabling faster robot deployment. The framework uses an LLM-based “prompt engineering” approach that generates task …

Evaluation Of Waste Plastic Addition Via Dry Method On Asphalt Mixture Performance, Isabella Madeira Bueno

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Incorporating waste plastic (WP) into hot mix asphalt (HMA) offers a promising approach to enhance recycling rates and improve asphalt concrete (AC) performance, particularly in moisture damage resistance. However, results vary widely due to differences in WP types, sizes, and mixing methods. The lack of standardized procedures, especially for the dry process, has led to inconsistent integration and unclear roles of WP in AC mixtures. Studies suggest that introducing WP to pre-heated aggregates at temperatures exceeding its melting point can enhance mixture resistance to rutting, cracking, and moisture damage. In this context, this study was conducted in two phases to …

A Discrete-Time Adaptive Sliding Mode Controller For A Multicopter With A Suspended Payload, John Helzer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents a Discrete-time Adaptive Sliding Mode Controller (DASMC) for control of a multicopter with a suspended payload. DASMC is designed to stabilize the multicopter at a desired position while minimizing the load oscillations induced by a significant hanging payload. The proposed DASMC minimizes the need for system-specific parameters like tunable gains and improves robustness to both external disturbances and model uncertainties compared with existing controllers. The controller is designed for direct digital implementation on a variety of multicopter platforms with considerations like discrete-time design, adaptive gain shrinking, and saturation handling. When deployed on a real multicopter in an …

Performance Characterization And Mechanistic Study Of Dry Process Wr/Sbs Composite Modified Asphalt Mixture, Hongfu Liu, Xiangyang Ren, Wenwen Ge, Zhengwei Yi, Dongzhao Jin, Xinghai Peng, Songtao Lv

Michigan Tech Publications

The dry process modification is characterized by simplicity, flexibility, low energy consumption, and low pollution, making it an ideal choice in pavement repair engineering. This study aims to optimize the use of waste rubber powder and SBS modifiers in dry process composite modification by preparing dry process WR/SBS composite modified particles (WR/SBS CMP) using a twin-screw extruder. The optimum mixing content of modified particles was determined through comparative analysis of pavement performance of dry process WR/SBS composite modified, wet-process SBS-modified, and matrix asphalt mixtures. The rheological properties and modification mechanism of the asphalt binder extracted from these mixtures were tested …

Jme 4110: Automatic Umbrella Opener, Sam Nieder, Adam Freeman

Washington University / UMSL Mechanical Engineering Design Project JME 4110

Manually opening and closing a patio umbrella can be time consuming and laborious. While there are remote controlled umbrellas for sale, they are expensive and may not be a reasonable option for most people. Our task was to create a device that can be retrofitted onto any patio umbrella, that allows it to be opened and closed remotely.

Jme 4110: Design And Evaluation Of A Remote-Operated Tool For High-Ceiling Light Bulb Maintenance, Faiq Kureshi, Austin Carr, Phuc Truong, Klevis Malaj

Washington University / UMSL Mechanical Engineering Design Project JME 4110

Changing light bulbs in high ceilings is a common but hazardous task. Existing tools are awkward, unstable, and often lead to dropped bulbs, damaged fixtures, or the need for ladders, increasing both risk and effort. There is a clear need for a safe, accurate, and efficient solution that allows bulb replacement from the ground without compromising speed or precision

Advancing Food Nutrition Estimation Via Visual-Ingredient Feature Fusion, Huiyan Qi, Bin Zhu, Chong-Wah Ngo, Jingjing Chen, Ee-Peng Lim

Research Collection School Of Computing and Information Systems

Nutrition estimation is an important component of promoting healthy eating and mitigating diet-related health risks. Despite advances in tasks such as food classification and ingredient recognition, progress in nutrition estimation is limited due to the lack of datasets with nutritional annotations. To address this issue, we introduce FastFood, a dataset with 84,446 images across 908 fast food categories, featuring ingredient and nutritional annotations. In addition, we propose a new model-agnostic Visual-Ingredient Feature Fusion (VIF2 ) method to enhance nutrition estimation by integrating visual and ingredient features. Ingredient robustness is improved through synonym replacement and resampling strategies during training. The ingredient-aware …

Data Annotations, Bradley M. Ratliff

Model Desert Terrain Monochromatic DoT Dataset

Pixel-wise object masks for each polarimetric scene in ASL file format for the Model Desert Terrain Monochromatic DoT data.

Performance Enhancement In Rewound Industrial Retrofit Solutions For Five- And Six-Phase Permanent Magnet Assisted Synchronous Reluctance Machines, Kotb B. Tawfiq, Ayman M. El-Refaie, Peter Sergeant, Hatem Zeineldin, Ahmed Al-Durra, Ehab F. El-Sadaany

Electrical and Computer Engineering Faculty Research and Publications

This paper investigates upgrading aging three-phase Permanent Magnet Assisted Synchronous Reluctance Machines (PMaSynRMs) into multiphase configurations—specifically six- and five-phase windings—without modifying the existing stator or rotor laminations. This retrofit supports circular economic principles by extending machine life and reducing material waste and cost. Four configurations are examined: the original three-phase winding, asymmetrical six-phase winding, symmetrical six-phase winding, and five-phase winding. The feasibility of rewinding existing three-phase stators is explored for different slot/pole combinations. Balanced rewound five-phase windings are feasible only when the stator's slot/pole ratio is greater than or equal to 9. Both symmetrical and asymmetrical rewound six-phase windings are …

Advances In Noninvasive Imaging For Detecting Radiation-Induced Lung Injury (Rili), Austen Nissen, Said H. Audi, Anne V. Clough, Brian Fish, Amit Joshi, Meetha Medhora, Jason Walter Sidabras, Heather A. Himburg

Biomedical Engineering Faculty Research and Publications

Purpose: Dr. Richard Hill performed pioneering work in the field of radiation-induced normal tissue injury to the lung including noninvasive imaging studies aimed at identifying imaging biomarkers of radiation-induced lung injury (RILI). RILI is a life-threatening toxicity of radiation exposure relevant to both cancer patients undergoing thoracic radiation therapy (RT) and victims of accidental radiation exposure. The ability to detect RILI noninvasively has the potential to guide treatment planning for RT and, in the case of victims of acute radiation exposures, inform the decision to start mitigative therapies. As part of this special issue of IJRB honoring Dr. Hill’s many …

Designing A Portable And Accessible Diffuse Reflectance Spectroscopy System For Real-Time Detection Of Cervical Intraepithelial Neoplasia, Allison Scarbrough, Diana Moses, Tongtong Lu, Bing Yu

Biomedical Engineering Faculty Research and Publications

Significance: Over 80% of cervical cancer cases occur in lower-to-middle income countries (LMIC’s). This is partly because current screening techniques lack affordability, accessibility, and/or reliability for use in LMIC’s.

Aim: To develop an optical technique for cervical cancer screening that is affordable, accessible, and reliable for use in LMIC’s.

Approach: We developed a portable diffuse reflectance spectroscopy (DRS) system, which costs < $2500 USD to manufacture, and employs a Raspberry Pi to extract the absorption (μ_a) and reduced scattering (μ'_s) coefficients of biological tissue. The system was subject to travel and intentional rough handling. It was further used to capture 320 DRS spectra taken from 64 tissue-mimicking phantoms. Two …

Identification Of Authentic Gnss Signals In Time-Differenced Carrier-Phase Measurements With A Software-Defined Radio Receiver, Zhen Zhu, Sanjeev Gunawardena, Eric Vinande, Jason Pontious

Faculty Publications

The time-differenced carrier phase can be computed from measurements recorded by a multi-global navigation satellite system software-defined radio receiver such as PyChips, from which the user displacement and receiver clock drift can be solved. PyChips is able to simultaneously track authentic and inauthentic signals in separate channels, which makes it possible to observe both types of measurements with corresponding navigation data. A random sample consensus algorithm has been introduced to assess the consistency between the measurements and data. This algorithm successfully separated authentic channels from inauthentic channels when they are broadcast simultaneously.

Conservation Management Effects On Soil And Agronomic Properties In A Furrow-Irrigated Corn System In East-Central Arkansas, Jeferson P. Pimentel, Christopher G. Henry, Kris R. Brye, Benjamin R. Runkle, Amanda J. Ashworth, Edgar Mersiovsky, Kevin C. Thompson

Biological and Agricultural Engineering Faculty Publications and Presentations

Cover crops can improve soil physical properties and help to sustain agricultural crop yields. A 6-year study conducted from 2017 to 2022 examined the effects of conservation soil management practices in a furrow-irrigated continuous corn (Zea mays L.) system on a silt-loam soil (Typic Albaqualf) in the Lower Mississippi River Delta region of eastern Arkansas. This study compared the effects of conventional tillage (CT), no-tillage (NT), and no-tillage with cover crops (CC) in selected soil physical and chemical properties (i.e., soil bulk density (D b), porosity (& fnof;t), field capacity (Theta FC), Permanent wilting point (Theta PWP), Plant available water …

Cell-Free Protein Synthesis Reactor Formats: A Brief History And Analysis, Dallin M. Chipman, Anna C. Woolley, Davu N. Chau, William A. Lance, Joseph P. Talley, Tyler P. Green, Benjamin C. Robbins, Bradley Charles Bundy

Faculty Publications

Cell-free protein synthesis (CFPS) has transformed protein production capabilities by eliminating cellular constraints, enabling the rapid expression of difficult-to-produce proteins in an open, customizable environment. As CFPS applications expand from fundamental research to industrial production, therapeutic manufacturing, and point-of-care diagnostics, the diverse array of reactor formats has become increasingly important yet challenging to navigate. This review examines the evolution and characteristics of thirteen major CFPS reactor formats, from traditional batch systems to advanced platforms. The historical development of CFPS reactors from the 1960s to present day is presented. Additionally, for each format, operational principles, advantages, limitations, and notable applications are …

Ac Electric Fields Manipulate And Concentrate Dna Molecules On Electrodes, Akila Wijesinghe, Dharmakeerthi Nawarathna

Graduate Student Government Association Research Conference

Point-of-care (POC) electric field-based biosensors have emerged as a promising tool to detect early cancer biomarkers such as circulating tumor DNA (ctDNA), microRNA (miRNA), and proteins. To be effective in screening in clinical settings, these biosensors must be simple and easy to use. In this study, we have studied the manipulation of short DNA molecules suspended in a sessile drop to achieve this goal. Alternative current (AC) electric fields were used to polarize DNA molecules and produce dielectrophoretic (DEP) force on DNA molecules. DEP force is used to manipulate polarized DNA molecules towards the higher electric field gradients (toward the …

The Utilization Of Basic Oxygen Furnace Slag As Fine Aggregates In Concrete: Physical, Mechanical, And Durability Properties, Hakan Ozkan

Journal of Sustainable Construction Materials and Technologies

This study examines the feasibility of using basic oxygen furnace slag (BOFS) as an alternative to fine crushed limestone aggregate in concrete. BOFS is sourced from two steel production facilities in Türkiye, designated as I-BOFS and E-BOFS. The experimental results showed that as the E-BOFS aggregate replacement ratio increased, the water-to-cement (w/c) ratio increased to maintain the target workability. The concrete mixtures incorporating E-BOFS exhibited consistent reductions in the compressive strength with an increase in the BOFS ratio. At the same time, I-BOFS maintained higher compressive strength, with only minor losses up to 80% of the substitution ratio. Flexural strength …

Development Of A Self-Cured Alkali-Activated Mortar, Kübra Ekiz Barış

Journal of Sustainable Construction Materials and Technologies

Alkali-activated mortars (AAM) can be produced with self-curing (SC), which supplies internal moisture to accelerate alkaline-activation reactions. The aim of using SC is to make AAMs with an early-age strength without any additional curing energy consumption and higher CO2 emissions, and to obtain in-situ practical advantages that enable the large-scale application of AAMs. The previous study produced natural pozzolan-based AAMs by applying energy-intensive heat (HC), microwave (MWC), and hybrid (HC+MWC) curing. This study investigates alternative curing regimes that reduce production energy without compromising material properties. The impacts of air curing (AC), water curing (WC), and SC on the properties were …

Naoh Molarity Effect On Mechanical And Hydrochloric Acid Resistance Of Geopolymer Mortar Based On Slag, Mahmoud Ziada, Zahraa Mohammed Kamil Al-Mayali

Journal of Sustainable Construction Materials and Technologies

The present research investigates the influence of different sodium hydroxide (NaOH) molarities on the mechanical characteristics and hydrochloric acid (HCl) resistance of geopolymer grouts manufactured from ground granulated blast-furnace slag (GGBS). Geopolymer mortars have attracted interest as sustainable substitutes for traditional cementitious materials due to their advantageous environmental effects and enhanced durability features. This study involved the fabrication of geopolymer mortar specimens by altering the NaOH molarity (M) from 6 M to 14 M. The mechanical and physical qualities were assessed using compressive strength, capillary water absorption, flexural strength, slump flow, and ultrasonic pulse velocity (UPV) tests. Subsequently, the geopolymer …

Effect Of Expanded Perlite And Exfoliated Vermiculite Aggregate Additives On Water Vapor Permeability Performance Of Cement-Based Lightweight Mortars, Lütfullah Gündüz, Şevket Onur Kalkan

Journal of Sustainable Construction Materials and Technologies

Vapor diffusion is the movement of water vapor molecules through porous materials such as wood, insulation products, and lightweight wall elements due to differences in vapor pressure. Vapor retarders are used to control vapor diffusion through wall sections and surfaces. All building materials provide some resistance to vapor diffusion, and the amount of resistance varies depending on the material's properties. These properties can vary with relative humidity and moisture content, age, temperature, and other factors. Vapor resistance is usually expressed using the inverse term of ``vapor permeability,'' which is the relative ease of vapor diffusion through a material. Water vapor …

Rubber-Modified Self-Compacting Mortar: Evaluating Setting Time And Strength Development, Navvar Makansi, Süleyman Ipek, Erhan Güneyisi

Journal of Sustainable Construction Materials and Technologies

The influence of using crumb rubber (CR) obtained from the second scraping of used tires as fine aggregate in manufacturing self-compacting mortar (SCM) was investigated experimentally in this study. To explore this, natural fine aggregate in SCM mixes was partially replaced with CR at levels ranging from 5% to 25% by total fine aggregate volume. Two mix series, one with a total binder of 500 kg/m3 and the other with a 540 kg/m3 binder, were designed at water-to-binder ratios of 0.40 and 0.33. Ordinary Portland cement (80% by weight) and fly ash (20% by weight) were used to manufacture mortars. …