Digital Commons Network^™

Predictive Maintenance In Naval Vessel Propulsion Systems For Enhanced Marine Operations Using A Bigmm-Hmm Framework With Divergence-Based Clustering, Farshid Javadnejad, Hyoshin John Park, Samuel Kovacic, Andres Sousa-Poza

Engineering Management & Systems Engineering Faculty Publications

This study introduces a BiGMM-HMM Integration Framework designed to improve predictive maintenance strategies for naval vessel propulsion systems, addressing the need for efficient and reliable operation in marine engineering applications. The framework effectively manages multimodal sensor data by leveraging a unique combination of Gaussian Mixture Models (GMMs) and Hidden Markov Models (HMMs) in a bidirectional architecture. It analyses the dynamic interactions between sensors and subsystems. Two preprocessing methods are evaluated: Method 1 focuses on subsystem interactions, employing divergence-based root cause analysis to identify key sensor variables by clustering of sensors and subsystems. In contrast, Method 2 processes the entire dataset …

A Comparative Analysis Of Preprocessing Filters For Deep Learning-Based Equipment Power Efficiency Classification And Prediction Models, Sang-Ha Sung, Chang-Sung Seo, Michael Pokojovy, Sangjin Kim

Mathematics & Statistics Faculty Publications

The quality of input data is critical to the performance of time-series classification models, particularly in the domain for industrial sensor data where noise and anomalies are frequent. This study investigates how various filtering-based preprocessing techniques impact the accuracy and robustness of a Transformer model that predicts power efficiency states (Normal, Caution, Warning) from minute-level IIoT sensor data. We evaluated five techniques: a baseline, Simple Moving Average, Median filter, Hampel filter, and Kalman filter. For each technique, we conducted systematic experiments across time windows (360 and 720 min) that reflect real-world industrial inspection cycles, along with five prediction offsets (up …

A Comparison Of Microcrystal Electron Diffraction And X-Ray Powder Diffraction For The Structural Analysis Of Metal-Organic Frameworks, Erik Biehler, Silvana Pagola, Daniel Stam, Johannes Merkelbach, Christian Jandl, Tarek M. Abdel-Fattah

Chemistry & Biochemistry Faculty Publications

This study successfully implemented microcrystal electron diffraction (microED) and X-ray powder diffraction (XRPD) for the crystal structure determination of a new phase, TAF-CNU-1, Ni(C₈H₄O₄)·3H₂O, solved by microED from single microcrystals in the powder and refined at the kinematic and dynamic electron diffraction theory levels. This nickel metal–organic framework (MOF), together with its cobalt and manganese analogues with formula M (C₈H₄O₄)·2H₂O with M = Mn ^II or Co^II, were synthesized in aqueous media as one-pot preparations from the corresponding hydrated metal chlorides and sodium terephthalate, as a promising `green' synthetic route to moisture-stable MOFs. The crystal structures of the …

Application Of Telc Model To Better Elucidate Neural Stimulation By Touch, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

Aim: This study is to better understand how the transient ion transport activity of touch receptors could change the graded potential to stimulate an action potential firing.

Methods: The latest transmembrane-electrostatically localized protons/cations charges (TELC) theory is employed for numerical analysis to calculate the neural touch signal transduction responding time required to fire an action potential spike.

Results: A neural action potential spike was constructed successfully using newly developed time-dependent TELC-based neural transmembrane potential integral equations (Equations 5, 6, and 7). The results explicated that the TELC curve has an inverse relationship with neural transmembrane potential since its curve appears …

Emerging Nanotechnology Approaches For Blood Disorders: A Comprehensive Review Of Nano-Hematinics And Plant-Based Nanomedicines, Hassan Abdulsalam Adewuyi, Khairat Shamsudeen, Fatima Mahmoud Muhammad, Adeola Kolawole Victor, Sakariyau Adio Waheed, Adepeju Matilda Adekoya, Kashim Ibrahim Muhammad, Blessing Temitayo Longe, Abdulgaffar Abdulquddus

Chemistry & Biochemistry Faculty Publications

Background: Disorders affecting blood components, such as anemia, coagulopathies, and hematologic malignancies, continue to pose significant global health burdens. Traditional therapies often fall short due to adverse effects, limited bioavailability, and insufficient targeting of disease sites.

Objective: This review synthesizes current advances in nano-hematinics and plant-based nanomedicines (phyto-nanomedicines) as innovative strategies for managing blood-related conditions. These nanoscale interventions are designed to enhance therapeutic precision, bioactivity, and safety.

Methods: A systematic review was conducted using major scientific databases including PubMed, Scopus, Web of Science, and ScienceDirect. Search terms were carefully selected to retrieve literature published between 2015 and 2024 that discussed …

Experimental Evaluation Of Corrosion Of Strands And Wires To Estimate Corrosion Rate In Grout And Concrete, Dipendra Shrestha

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Premature failure of prestressed and post-tensioned concrete structures is frequently caused by undetected corrosion of prestressing steel. Although extensive research has addressed corrosion rates in conventionally reinforced concrete, the interpretation of non-destructive parameters, such as half-cell potential (HCP) and concrete/grout resistivity, for estimating corrosion rates in prestressing steel are not adequately investigated.

This research experimentally evaluates chloride-induced corrosion of prestressing steels to establish material-specific relationships between in-situ measurable parameters and corrosion rate. Thirty-six macrocell specimens incorporating plain wires, indented wires, and seven-wire strands in structural concrete and commercial post-tensioning grout- half with pre-formed surface cracks, were subjected to accelerated cyclic …

Laser-Induced Graphene Sensor For The Electrochemical Detection Of Acetaminophen, Abdellatif Ait Lahcen, Mazhar Sher, Sikander Ameer, Gymama Slaughter

Center for Bioelectronics Publications

Here we present a simple and efficient method for fabricating laser-induced graphene (LIG) electrodes for the electrochemical detection of acetaminophen (AAP), a crucial analgesic and antipyretic that can become toxic at elevated concentrations. Unlike conventional sensors that require intricate chemical modifications, the fabricated LIG-based sensor eliminates the need for functionalization, offering a streamlined sensing solution. The LIG electrodes were characterized using scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy, which confirmed the formation of a highly porous graphene network with excellent purity and conductivity. Cyclic voltammetry analysis with a ferricyanide redox probe revealed a large electroactive surface area of 1.21 …

Centralized Deep Reinforcement Learning For Homogeneous Multi-Component Maintenance Optimization, Joseph W. Wittrock

Theses and Dissertations

This thesis explores an application of reinforcement learning (RL) in maintenance optimization. Recent advances in hardware-accelerated computation and deep learning have made RL a powerful tool for solving optimization problems which are too complex for traditional methods. Maintenance optimization involves improving the efficiency and effectiveness of maintenance activities through data-driven approaches, ultimately reducing costs and increasing asset availability. Making informed maintenance decisions is crucial to long-term sustainability.

A desirable maintenance policy maximizes a utility signal while minimizing the cost of maintenance. Techniques in sequential decision making such as dynamic programming (DP) and RL have found success in optimizing these maintenance …

แนวทางการบูรณาการโครงการความรับผิดชอบต่อสังคม กรณีศึกษากองทัพอากาศไทย, ศิริกัญญารัตน์ สวนสีดา

Chulalongkorn University Theses and Dissertations (Chula ETD)

การศึกษาครั้งนี้มีวัตถุประสงค์เพื่อเสนอแนวทางการบูรณาการโครงการความรับผิดชอบต่อสังคมขององค์กร (CSR Integration) ของกองทัพอากาศให้เชื่อมโยงกับวิสัยทัศน์ พันธกิจ ภารกิจหลักด้านความมั่นคง ยุทธศาสตร์ชาติ 20 ปีและเป้าหมายการพัฒนาที่ยั่งยืน (SDGs) โดยการทบทวนวรรณกรรมร่วมกับการสัมภาษณ์เชิงลึกกับผู้ที่เกี่ยวข้อง ซึ่งผลการศึกษาพบว่า กองทัพอากาศมีศักยภาพอย่างมากในการดําเนินกิจกรรมความรับผิดชอบต่อสังคมขององค์กรที่มุ่งเน้นการช่วยเหลือ สร้างความเข้าใจและความสัมพันธ์อันดีกับประชาชน แต่มีข้อจํากัดสําคัญ ได้แก่ การขาดความต่อเนื่องของโครงการจากการโยกย้ายกําลังพล ขาดระบบส่งต่องาน การประชาสัมพันธ์ที่ไม่ทั่วถึง ซึ่งแนวทางบูรณาการโครงการความรับผิดชอบต่อสังคมของกองทัพอากาศทั้งหมด 5 โครงการ ได้แก่ (1) โครงการด้านสุขภาพและคุณภาพชีวิต (2) โครงการพัฒนาศักยภาพคนและการศึกษา (3) โครงการสังคมปลอดภัยและวัฒนธรรมรับผิดชอบร่วม (4) โครงการชุมชนสีเขียว และ (5) โครงการพลังงานสีเขียวและการรับมือการเปลี่ยนแปลงสภาพภูมิอากาศ จะช่วยให้กิจกรรมความรับผิดชอบต่อสังคมของกองทัพอากาศที่มีอยู่ได้รับการต่อยอดและเชื่อมโยงกับเป้าหมายการพัฒนาที่ยั่งยืน (SDGs) จากเดิม 6 ด้านเป็น 13 ด้าน อีกทั้งขยายผลกรอบแนวคิด The “5 Ps” เพิ่มเติมใน 4 ด้าน ได้แก่ Planet People Prosperity และPartnership ที่ครอบคลุม ESG ได้ทุกด้าน รวมถึงเสนอการพัฒนาเชิงนโยบาย 4 ระดับ ตั้งแต่ระดับยุทธศาสตร์ องค์กร บุคลากร และสังคม เพื่อขับเคลื่อนกองทัพอากาศไปสู่การบูรณาการเชิงยุทธศาสตร์และการสร้างคุณค่าร่วม (CSV) สามารถพัฒนาเป็น “กองทัพเพื่อความมั่นคงและความยั่งยืนแห่งชาติ” ได้อย่างเป็นรูปธรรม

Electrical Homeostasis Of The Inner Mitochondrial Membrane Potential, Peyman Fahimi, Lázaro A. M. Castanedo, P. Thomas Vernier, Cherif F. Matta

Bioelectrics Publications

The electric potential across the inner mitochondrial membrane must be maintained within certain bounds for the proper functioning of the cell. A feedback control mechanism for the homeostasis of this membrane potential is proposed whereby an increase in the electric field decreases the rate-limiting steps of the electron transport chain (ETC). An increase in trans-membrane electric field limits the rate of proton pumping to the inter-membrane gap by slowing the ETC reactions and by intrinsically induced electroporation that depolarizes the inner membrane. The proposed feedback mechanism is akin to a Le Chatelier's-type principle of trans-membrane potential feedback control.

Correlation Of Internal Pressure To The Fundamental Aging Mechanism Of Li-Ion Batteries, Kayla Garcia

Electrical Engineering Theses - Archive

As technology continues to evolve, the demand for more reliable and longer-lasting batteries is growing rapidly in the electronics industry. Batteries are vital for powering a wide range of technologies, from smartphones and consumer electronics to automotive systems and high-end tools used across multiple sectors. Lithium-ion batteries (LIBs) have helped bridge the power and energy gap that these different technologies require while achieving sufficient efficiency and reliability to make carrying them around feasible and long lasting. To further enhance the performance and longevity of a these devices, a deeper understanding of the degradation mechanisms occurring inside LIBs is crucial. The …

Design And Validation Of A Multiple Axis, Passive 3d-Printed Ankle-Foot Prosthetic For Functional Gait, Brogan Rene Landeen

Dissertations and Theses

By 2050, an estimated 3.6 million individuals will be living with lower limb loss, with transtibial (below the knee) amputations being the most common type of lower limb surgery. Prosthetic devices are the standard of care for rehabilitating these amputees; each device is explicitly designed to enhance stability, energy storage and release, flexibility, and active propulsion. Prosthetic selection is based on user specifications, including activity level, comfort, and anthropometry. Despite the consensus that prosthetics help to restore impaired gait, traditional, commercial prosthetics fabricated with carbon fiber via injection molding are expensive and often require multiple modifications by a prosthetist before …

Private Property Vs. Public Access: Socio-Engineering Framework For Managing Non-Meandering Waters In South Dakota’S Prairie Pothole Region, Lydia Loken, Sushant Mehan

The Journal of Undergraduate Research

This study addresses the growing importance of balancing private ownership and public interest of Non-Meandering Waters (NMWs) overlaying private property in the South Dakota Prairie Pothole Region (PPR) through both a legal and socio-engineering lens. This study aims to develop an integrated management framework for Non-Meandering Waters in the South Dakota Prairie Pothole Region that combines water allocation principles, the Public Trust Doctrine, and water quality objectives to guide policy decisions, ensuring equitable access, long-term sustainability, and a balanced approach to both public and private interests. Data collection from October 2024 through February 2025 and included a literature review of …

Little Problems: Photosynthetic Textile Treatments As A Source Of Oxygen, Morgan Campbell

Open Access Master's Theses

During human space travel, oxygen (O2) must be stored and carried aboard the shuttle for the entire journey; compressed O2 is highly flammable and combustible, thus doing so puts the crew’s lives at risk in the event of a fire (Mandel, 2019). By creating O2 onsite, the necessity of compressed O2 canisters and the associated risks can be reduced or erased entirely. Photosynthesis, the process through which plants convert atmospheric carbon dioxide (CO2) into O2, is one method of creating O2 (Lorch, 2020). The National Aeronautics and Space Administration (NASA) has experimented with photosynthetic O2 systems since its inception but …

Development Of An Autonomous Lab-On-Paper Device For Enzymatic Activity Assays- Proof Of Concept, Cameron Hahn

Open Access Master's Theses

This work aims to build on URI’s autonomous Lab on Paper (LoP) platform technology, which was used to conduct enzyme-linked immunosorbent assays (ELISAs), to conducting enzymatic activity assays. This requires new optimizations and designs to accommodate the test. In this work we use alkaline phosphatase (ALP) enzyme as the model analyte for the proof-of-concept. To accompany the new device, new MATLAB analytical tools were written and tested, to aid in robust colorimetric signal analysis. The test fixture was designed to be reusable, when a new paper circuit and reagent vials are supplied, however, it was assumed that an eventual final …

Predicting The State Of Health Of Samsung 25r Lithium Ion Batteries, Matthew O'Donnell

Open Access Master's Theses

This thesis may contain material at the Controlled Unclassified Information (CUI) level. The full document cannot be released.

Magnetic Heating Efficiency Of Magnetite Nanoparticles: Dependence On Size And Alternating Magnetic Field, Sarah E. Kubican

Theses and Dissertations--Biomedical Engineering

Magnetic heating mediated by magnetic iron oxide nanoparticles (MION) has several clinical applications including cancer thermal therapy, tissue thawing for organ preservation, and magnetogenetics. However, current models of magnetic heating, including the widely used linear response theory, inadequately predict MION heating efficiency. An experimental study covering alternating magnetic field (AMF) strengths and frequencies ranging from 3.98 – 27.85 kA/m and 103.6 – 984.1 kHz, respectively, with a range of MION core diameters 9.5- 30.3 nm was conducted to elucidate the relationships between these AMF parameters and MION sizes and the resulting heating efficiencies. Heating efficiency was found to increase approximately …

Pathogen Surveillance Of Viruses And Antimicrobial Resistance Through Wastewater Based Epidemiology, William Strike

Theses and Dissertations--Biomedical Engineering

Pandemic surveillance is a cornerstone in public health safety, as it enables identification of pathogens circulating within a community before they become widespread outbreaks. Wastewater based epidemiology has blossomed in recent years due to its success in the SARS-CoV-2 pandemic, but this form of public health surveillance has a global equity problem. A large majority of the wastewater-based surveillance work has been done in large metropolitan cities with access to advanced testing infrastructure, which poses a challenge as we consider where pandemics have historically emerged. Therefore, there is a need to identify, adapt, and develop workflows to meet the needs …

Measuring Accessibility Of Electric Vehicle Charging Infrastructure: A Case Study In Kentucky, Oluwasola Elijah Fagbohun

Theses and Dissertations--Civil Engineering

This thesis assesses spatial accessibility to electric vehicle charging infrastructure across Kentucky by investigating methodological approaches to measure accessibility: provider-topopulation ratios, regional accessibility metrics, and several methods in the family of gravity models. The Enhanced Two-Step Floating Catchment Area method was employed to measure electric vehicle charging station accessibility across Kentucky using a network-based approach in ArcGIS Pro. The analysis integrated 2023 American Community Survey 5-year Census block group data, Kentucky road network datasets, charging station locations from the Alternative Fuels Data Center, and Alternative Fuel Corridor designations. We examined existing infrastructure and proposed stations outlined in the Kentucky electric …

A Scoring Approach For Evaluating And Ranking Complete Streets Projects, Eirini Stavropoulou

Theses and Dissertations--Civil Engineering

Complete Streets is a vital strategy for developing an equitable transportation network that provides access to all users and transportation options to communities. A growing interest in this concept has been noted in the United States, with over 1,700 Complete Streets-related policies implemented nationwide. The Kentucky Transportation Cabinet (KYTC) has developed the “Complete Streets, Roads, and Highways Manual” and the “Complete Streets Policy” aiming to promote a safer and more inclusive transportation system statewide through Complete Streets implementation. A recent KYTC initiative was the development of a scorecard to systematically evaluate Complete Streets projects competing for funding. The scorecard is …

Adjusting Benefit Estimation For Pedestrian And Bicycle Facilities For Kentucky, Dionysios Tzamakos

Theses and Dissertations--Civil Engineering

The growing shift of commuters towards active transportation (AT) in the U.S. has led transportation agencies to place greater emphasis on improving bicycle and pedestrian facilities. Such improvement efforts can be integrated into multi-modal highway planning and development or be implemented through stand-alone pedestrian and bicycle projects both resulting in additional AT demand. Measuring the benefits of infrastructure improvement is central to prioritizing projects, as active transportation contributes to health, congestion reduction, safety, and recreational benefits. This study aims to calibrate the demand estimates for walking and cycling and estimate the associated benefits for the state of Kentucky. Population density …

Advancing Vapor Intrusion Science Using Systematic Frameworks To Foster Informed Decision Making, Hong Cheng Tay

Theses and Dissertations--Civil Engineering

Vapor intrusion, the migration of subsurface vapors into indoor air spaces, is an important source of indoor air contamination to consider at hazardous waste sites contaminated by volatile organic compounds (VOCs). There is considerable uncertainty and variability in the factors that influence vapor intrusion processes, which poses a significant challenge for decision making, despite advancements in vapor intrusion science. This dissertation consolidates knowledge from existing scientific advances and investigates scientific gaps associated with the vapor intrusion preferential pathway conceptual model (i.e. conduit vapor intrusion), associated with the vapor entry pathway into buildings via sewer systems. The overall goal of this …

Earthquake Wrangler: Leveraging Ios Technology For Earthquake Detection And Early Warning Application To Enhance Public Safety., Luis F. Salome

Theses and Dissertations--Civil Engineering

Earthquakes are devastating natural phenomena and generate secondary hazards such as tsunamis, landslides and fires. Their catastrophic impacts span both developed nations including the United States, Japan, Turkey, and Italy and developing countries such as El Salvador, Haiti, Nepal and the Philippines, where disparities in early warning infrastructure remain important. Seismic events start with stress waves generated by tectonic plate motion, with body waves (P- waves and S-waves) and surface Rayleigh and love waves that carry energy through the earth. While some regions have adopted advanced early warning systems based on seismic hazard models and strong ground motion analysis, others …

Collision Avoidance Information System Utilizing Machine Learning Image Recognition, Michael W. Long

Theses and Dissertations--Mining Engineering

This thesis addresses significant safety challenges presented by powered haulage fatalities in underground mining by developing and evaluating a machine learning-driven Collision Avoidance Information System (CAIS). The research utilized a ZED 2i camera to capture both RGB and depth data for enhanced spatial awareness in visually limited underground environments. A specialized dataset of underground mining equipment was captured from limestone and zinc mines, annotated, and used to train a segmentation network. The CAIS was field-tested in diverse underground settings, achieving an accuracy of 82% in a limestone mine similar to the training data, but a lower accuracy of 45% in …

Temporal Machine Learning For Predicting Accidents And Violations In The Mining Industry, Nathan T. Kelley

Theses and Dissertations--Mining Engineering

This thesis examines the predictive capability of a temporal machine learning model for forecasting future accidents and violations at individual mines, based on historical data. Mine accidents were categorized by accident classification and violations were categorized by the Part Section. The primary datasets utilized were the mine safety and health administration’s (MSHA’s) Accident Injuries and Violations datasets. The available datasets were cleaned and organized by mine type and commodity, then divided into separate subsets for training, validating, and testing. Different models, cutoff metrics, learning rates, number of hidden layers, data processing methods, data processing divisions, number of points observed …

An Autonomous Robotic Inspection System For Underground Mines Using Unmanned Aerial Vehicles (Uavs), Kiazoa M. Joao

Theses and Dissertations--Mining Engineering

Underground mining environments pose unique safety challenges for workers due to poor visibility, unstable ground conditions, and the absence of GPS signals. To adhere to safety and health standards, underground mines are required to perform safety inspections regularly. Conventional safety inspections require personnel to enter the hazardous environment, highlighting the need for a safer, remote alternative. The use of UAVs for safety inspection in underground mines is a somewhat novel idea but has shown great promise. While Unmanned Aerial Vehicles (UAVs) cannot eliminate all hazards associated with mining, they provide critical support by accessing hazardous or restricted zones that are …

Simplified Molecular Diagnostics Methods For Environmental Testing Of Pathogens And Other Applications, Mohammad Dehghan Banadaki

Theses and Dissertations--Mechanical and Aerospace Engineering

Environmental Surveillance (ES) has emerged as a powerful tool to monitor the emergence and persistence of a pathogen within a facility or community using wastewater/water analysis. Over the past four years, implementation of ES has experienced an explosive acceleration, driven by efforts to monitor the spread of SARS-CoV-2, which has made ES a routinely used public health tool in many locations. We can now use ES to measure the emergence/presence/abundance of different viruses (e.g., SARS-CoV-2, influenza, mpox), bacteria (e.g., E. coli, V. cholerae, antibiotic-resistant strains), fungi (e.g., C. auris), and other biological markers indicative of infectious diseases. However, its broad …

Acoustic Characterization Of A Quadcopter Using A Test Stand, Jared Schmal

Theses and Dissertations--Mechanical and Aerospace Engineering

Unmanned Aerial Vehicles (UAVs) with multirotor propulsion and control, commonly called drones or multicopters, generate a complex acoustic field that is not entirely understood. Many components and their interactions contribute to the overall noise level and behavior of the acoustic field. However, performing acoustic measurements on a multicopter in a confined space, such as a small anechoic chamber, can be an extremely difficult and time-consuming process. A test stand was developed to allow for rapid and safe acoustic measurements in a controlled environment. The design, development, and initial measurements are discussed. The performance and acoustic response are assessed to examine …

In-Situ Informed Modeling And Characterization Of Friction And Built-Up Edge In Machining Of Aerospace Alloys, Avery Hartley

Theses and Dissertations--Mechanical and Aerospace Engineering

Machining is by no means a new manufacturing process. However, it is separated from other traditional deformation processes by its extreme temperatures and strain rates. The function and life of a multitude of products and mechanical components are dependent on the material properties induced by changing the surface through machining. Furthermore, the tools used within machining are often expensive and material reserves are sparse. The understanding the mechanics of the machining process, especially related to the friction of the tool and workpiece, helps to further the life of tools and parts to minimize economic and environmental impact.

Current friction modeling …

High-Altitude Balloon-Launched Uncrewed Aircraft System Measurements Of Atmospheric Turbulence And Qualitative Comparison With Infrasound Microphone Response, Anisa Haghighi

Theses and Dissertations--Mechanical and Aerospace Engineering

This study explores the use of a balloon-launched uncrewed aircraft system (UAS) to measure atmospheric turbulence in the troposphere and lower stratosphere using both wind velocity measurements and infrasonic acoustic energy. The UAS, a glider configured for autonomous descent along a predefined trajectory, had on board, in situ sensors to capture thermodynamic and kinematic atmospheric parameters. Additionally, it carried an infrasonic microphone to evaluate its potential for remotely detecting clear-air turbulence by capturing infrasonic waves. The system’s performance was assessed over the course of three test flights conducted in New Mexico, USA, in 2021. The descent enabled high-resolution profiling, with …