Digital Commons Network^™

Study And Simulation Of Model-Reference Adaptive Control Via The Heffron-Philips Model For Enhanced Power System Stability, Laila Ayman Dallol

Graduate Theses and Dissertations

Improving power transmission and quality has been an area of research interest over the past decades and was improved using renewable energy resources, mainly wind, and solar generation. Renewable energy penetration into power grids aims to replace some traditional synchronous generators, affecting the overall power system with reduced gas emissions that help with climate change and pollution issues. However, renewable generation in power systems ranging from microgrids to national grids is subjected to large disturbances that affect its transient stability, which is measured by its critical clearing time. As increased amounts of renewable generation connected to power systems have resulted …

Unraveling Nucleation Mechanisms In Membrane Distillation: A Molecular Dynamics And Enhanced Sampling Approach, Nazanin Abbasi

Graduate Theses and Dissertations

Membrane distillation offers a promising route for desalination but remains limited by salt scaling, where mineral crystals nucleate and grow in concentrated brines. To inform strategies that mitigate scaling, this thesis investigates homogeneous nucleation in supersaturated aqueous NaCl solutions using molecular dynamics and enhanced sampling techniques. Several collective variables (CVs) are tested to capture the early stages of ion aggregation and crystal formation, including ion–ion coordination number, dehydration, and bond orientational order parameters Q₄ and Q₆. Enhanced sampling techniques, such as metadynamics and umbrella sampling, are employed to overcome the high free energy barriers associated with the formation of critical …

Volume Status Detection With Integral Pulse Frequency Modulation Model Of Peripheral Venous Pressure, Jeremiah Rhys Wimer

Graduate Theses and Dissertations

This thesis studies the effectiveness of utilizing a modified integral pulse frequency modulation (IPFM) algorithm to synthesize peripheral venous pressure (PVP) waveforms for the detection of several physiological conditions using logistic regression. PVP waveforms are collected from 18 human patients and 4 porcine subjects. Human data are used to train models for determining the hypovolemic status of the patient, while the porcine data are used to train models for determining level of anesthesia and detecting internal hemorrhaging. In the human dataset, the waveforms collected from the 18 patients are classified into two groups according to serum chloride levels: resuscitated (≥100 …

Flood-Level Estimation Using Aerial Imagery, Yisen Zhang

Electrical & Computer Engineering Projects for D. Eng. Degree

Reliable flood-level estimation using aerial UAV (Unmanned aerial vehicle) imagery is essential for effective post-disaster assessment and rapid emergency response. This study utilizes a UAV-based dataset, referred to as the UVA dataset, which integrates multiple public datasets and manually labeled UAV images, together with a multi-stage vehicle-centric framework for flood-depth estimation. The UVA dataset integrates images from multiple public sources, including Unmanned Drone Water Assessment (UDWA), Unmanned Aerial Vehicle Detection and Tracking (UAVDT), Car Parking Lot (CARPK), and additional UAV-view images collected from the internet, followed by manual annotation for water depth, viewing angle, and altitude labels. In the proposed …

An Integrated Modeling Framework To Evaluate Circularity Of The Corn–Water–Ethanol–Beef Nexus, Heydi Han

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

This dissertation examines the transition from conventional linear agricultural and food bioenergy systems toward more circular, resilient, and resource-efficient configurations. Prior research indicates that spatial and temporal variability in soil, weather, animal biological responses, and management decisions strongly influences productivity, nutrient-use efficiency, and profitability. Studies have also shown that a diversified circular system can buffer these sources of variability, improving stability and adaptive capacity. Building on these insights, the central focus of this work is to develop an integrated modeling framework to evaluate circularity within the Corn-Water-Ethanol-Beef (CWEB) nexus and explore how climate variability and management choices shape system-wide performance. …

Synthesis And Study Of Stable Organic Radicals For Mri Contrast Agents And New Materials, Sabina Dhakal

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

The first part of this dissertation focuses on the design, synthesis, and characterization of a thermally robust S =1/2 phototetrazolinyl monoradical and the development of synthetic methodologies for a high-spin (S = 1) phototetrazolinyl diradical. Electrochemical studies of the phototetrazolium cation (precursor to the monoradical) revealed a remarkably narrow electrochemical band gap (Ecell ≈ 0.82 V), suggesting promising electrical conductivity. Thermal analysis of the monoradical demonstrated excellent stability, with the onset of decomposition at 232 °C. Building on the excellent thermal stability and promising properties for electrical conductivity of the monoradical, we developed two condensation-based synthetic routes that provide viable …

Rainfall-Runoff Modelling In An Indonesian Humid Tropical Area Using Satellite-Based Precipitation Products, Noordiah Helda

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

This dissertation explores three rainfall-runoff models in the humid tropical regions of Indonesia using satellite-based precipitation products (SBPPs) and develops integrated machine-learning modeling frameworks. Several ground-based observations from BMKG (Badan Meteorologi, Klimatologi, dan Geofisika (also known as the Indonesian Agency for Meteorology, Climatology, and Geophysics)) stations across Indonesia (133−165 stations) are compared and evaluated against satellite products, indicating that GPM performs well, with R-squared values ranging from 0.54 to 0.76 and correlation coefficients ranging from 0.45 to 0.69, respectively.

In the Martapura Watershed, South Kalimantan, due to a lack of observational discharge data, streamflow was generated using the FJ Mock …

Residential Hvac Installation Faults: Field Prevalence, Drivers, And Energy Impacts, Seyed Ali Rooholghodos

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

Faults in residential comfort systems can have detrimental effects on the performance of the system, reducing the energy efficiency, affecting indoor comfort, and shortening equipment lifespan. Many of the faults occur at installation. However, there has not previously been a systematic and nationally representative study to indicate the prevalence of the faults, meaning the distribution of faults by fault type and fault intensity. Understanding true fault prevalence is essential to be able to identify derivers, and to assess the incremental electricity consumption of the new installation systems.

This study presents on-site data from 341 new central cooling systems—air conditioners and …

Large-Scale Experimental Study On The Impact Of Air Cleaning & Ventilation On Indoor Air Quality And Student Illness-Related Absenteeism, Daud Nosham

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

This large-scale randomized experimental field study investigated the effect of portable air purifiers (PAPs) on classroom’s air quality and student’s illness related absenteeism. PAPs were installed in 317 classrooms from various school districts located in Eastern Nebraska. The classrooms were randomly assigned into four conditions: three treatment conditions (T1, T2 & T3) and one control condition (device without any filter). T1 was equipped with HEPA filters, T2 added Activated Carbon (AC) layer to HEPA, and T3 further integrated Germicidal Ultraviolet (GUV) alongside HEPA and AC filters. The measured variables were carbon dioxide (CO2), fine particles (PN2.5) and coarse particles (PNcoarse), …

Air Force Institute Of Technology Research Report 2023, Air Force Institute Of Technology

AFIT Documents

This report summarizes the research activities of the Air Force Institute of Technology's Graduate School of Engineering and the Graduate School of Logistics and Acquisition Management. It describes research interests and faculty expertise; list student theses/dissertations; identifies research sponsors and contributions; and outlines the procedure for contacting either school.

Polypropylene/Polyethylene Blends With Asymmetric Viscosity: Fabrication, Characterization, And Recycling Potential, Bernadine Daichendt

All Dissertations

Polyolefin materials, polypropylene (PP) and polyethylene (PE), are widely used in day-to-day life both commercially and industrially, offering versatile applications due to their mechanical and chemical properties. The high consumption rate of these materials makes them important targets for recycling efforts. However, there are multiple contributing factors leading to low recycling of PP and PE, chiefly sorting factors: chemical similarity, changed properties after multiple rounds of processing, and the use of processing aids. It is necessary to point out that, because of multiple melt processing cycles, recycled PP has decreased molecular weight due to chain scission. Conversely, recycled PE molecular …

Degradation Of Cobalt Chrome Molybdenum Hip And Knee Implants In Vivo And In Vitro, Peter William Kurtz

All Dissertations

Cobalt Chrome Molybdenum (CoCrMo) remains a popular material choice for femoral condyles in total knee arthroplasty and for acetabular liners in dual mobility total hip designs. CoCrMo has been phased out of conventional THA designs due to its correlation with adverse effects such as ALTR and ALVAL. It is less understood if the mechanisms (i.e. abrasive wear to the surface of the implant) that release metal ions into the surrounding tissue occur at similar rates as seen in conventional THA. Additionally, it is unknown what effect the secondary damage modes such as electrocautery damage and adhesive wear have on these …

Power Distribution Controller For Formula Sae Vehicles, Michael Yuen

Electrical Engineering

The Power Distribution Controller (PDC) is designed for low-voltage (12V) automotive applications, specifically Formula SAE vehicles. It aims to replace the current and outdated MOSFET-based system, which suffers from inefficiencies such as lossy current sense resistors and limited configurability. Instead, this new system uses a PROFET-based architecture controlled over the Controller Area Network (CAN) and an updated microcontroller, enabling intelligent power management and data logging.

Designed with FSAE regulations in mind, the PDC not only enhances the reliability of low-voltage systems but also provides a quickly adaptable solution to fuse boxes. It achieves this by providing firmware-adjustable overcurrent protection, incorporating …

Development And Application Of Deep-Level Spectroscopy Systems For Characterizing Irradiation-Induced Traps In Gallium Nitride Schottky Diodes, Donald Hodgson

Open Access Theses & Dissertations

Crystal defects are a natural consequence of the gallium nitride (GaN) crystal growth process and may also be introduced by exposure to radiation environments, leading to degradation of device performance. Detection of these defects are completed through various methods of characterization including Deep-Level Transient Spectroscopy (DLTS) and Deep-Level Optical Spectroscopy (DLOS). In this work, a custom DLOS measurement system was developed and validated to investigate deep-level defects in GaN Schottky diodes before and after irradiation. GaN Schottky diode structures and wafer layouts were designed based on baseline technology provided by the University of New Mexico (UNM) and modified to meet …

The Hunga Volcanic Eruption Atmospheric Impacts Report, Simon Carn

Michigan Tech Publications

No abstract provided.

Deep-Learning-Enhanced Automated Coherent-Light Diffraction System For High-Speed, Highly Accurate Strain-Specific Foodborne Bacterial Recognition, Yang Tian, Ziyu Liu, Yinuo Huang, Ramesh Bahadur Bist, Yiting Xiao, Samantha Marrianne Howe, Tsung Cheng Tsai, Terry Howell, Jeyam Subbiah, Michael L. Looper, Dongyi Wang

Biological and Agricultural Engineering Faculty Publications and Presentations

Rapid, accurate differentiation of bacterial pathogens at both species and strain levels is critical for clinical diagnostics, food safety, and epidemiological surveillance. We report a fully automated laser-diffraction platform that achieves rapid, label-free identification of bacterial pathogens at both species and strain levels. The system integrates dual cameras, an automated X-Y stage, and deep-learning classifiers to deliver sub-second, nondestructive diagnostics without reagents or culture. Using diffraction patterns from eight strains, including Escherichia coli O157:H7, K12, ATCC 25922, F18, Salmonella enterica, Listeria monocytogenes, Listeria innocua, and Staphylococcus aureus, a custom YOLO11x model attained 100 % Top-1 accuracy under five-fold stratified cross-validation …

Exploratory Diver Geotechnical Equipment (Edge), Angel Villicana, Merrick Zellers, Erik Heuchert, Lucas Heuchert

Mechanical Engineering

The goal of this report is to showcase how our final Core Sampler design and prototype address the needs of Navy Divers. Geotechnical equipment for Navy divers has not been updated since the early to mid-1980s, resulting in imprecise and outdated sampling methods. The primary purpose of this project is to enhance, modernize, and redesign a tool to collect a minimally disturbed core sample of the seabed for geotechnical evaluation. This report presents the full development of our project from concept to verification and final outcomes. It begins with the statement of disclaimer, followed by a four-panel executive summary and …

Intrinsic Disinfection Byproducts In Free Chlorine And Chloramine Systems: Formation Of Chlorite, Chlorate, Perchlorate, And Chloronitramide Anion, Julian L. Fairey, Ashley D. Pifer, David G. Wahman

Civil Engineering Faculty Publications and Presentations

Intrinsic disinfection byproducts are formed by reactions between disinfectant species and/or their decomposition products. In this review, we focus on a subset that accumulates in free chlorine and chloramine drinking water systems. First, we review the sequential formation of chlorite, chlorate, and perchlorate in hypochlorite feedstocks. Model simulations indicate chlorate and perchlorate can accumulate under realistic dosing conditions and can be managed with less concentrated feedstocks and climate-controlled storage. Second, we review the formation pathways of dichloramine and chloronitramide anion. Chloronitramide anion accumulation may be mitigated by increasing monochloramine stability and quenching reactive nitrogen species in its formation pathway.

Deterministic Methods To Improve The Field-Of-View For Direction Finding Using Sparse Digital Arrays, Nolan J. Egging

Master's Theses

Direction finding algorithms are used with digital phased arrays to determine the incoming angle of arrival (AoA) of an incident signal. These algorithms, and direction finding as a whole, have a wide range of civilian and military applications from radar, electronic reconnaissance, mobile communication, et cetera. However, for situations where the spacing between antenna elements needs to be large, gating lobes appear in the radiation pattern of analog arrays. This work demonstrates that for digital beamforming algorithms, the field of view (FoV) of a uniform linear digital array matches the grating lobe free range of a similarly spaced analog array. …

Development And Test Of An Automatic Mass Balancing System For Cal Poly's Spacecraft Attitude Dynamics Simulator, Cameron B. Zorio

Master's Theses

The Cal Poly Spacecraft Attitude Dynamics Simulator (SADS) is an ongoing project to develop an air-bearing platform capable of recreating on-orbit rotational dynamics with near frictionless and torque-free rotations. However, any offset between the platform's center of rotation and its center of mass will introduce a torque due to gravity.

This thesis presents the design, implementation, and experimental evaluation of a low-cost, automatic mass balancing system for the SADS to address this challenge. A new modular sliding mass system was developed that overcomes issues faced in previous iterations of the SADS, providing real-time positional control of the masses and a …

Using Hydraulic And Hydrologic Modeling To Determine Scour At Toro Creek Under Climate Change Conditions, Gabriel E. Alaniz

Master's Theses

ABSTRACT

This study evaluates bridge scour at the Toro Creek crossing of Highway 1 in Morro Bay, California, under present conditions and future climate conditions with more frequent extreme rainfall events. California infrastructure is becoming increasingly vulnerable to extreme storm events and increased intense precipitation events brought by climate change. This analysis focuses on the calculation of scour for both the northbound and southbound spans. Highway 1 plays a vital role in California’s coastal transportation infrastructure by carrying more than 20,000 vehicles daily (Caltrans, 2017). In this thesis, a hydrological model (HEC-HMS) is used to simulate runoff under present-day and …

A Low-Power Mixed-Signal Potentiostat System-On-Chip With Integrated Dual-Slope Adc, Seth Mcrobert

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

This thesis presents the design and characterization of a low-power mixed-signal potentiostat that was integrated with a 65 nm core in a SoC for low-power electrochemical sensing applications. The system integrates a low-noise transimpedance-based potentiostat front end with a 12-bit dual-slope analog-to-digital converter (ADC) for accurate current-to-digital conversion. The potentiostat core—comprising the control amplifier, current-mirror network, and transimpedance amplifier—consumes 38.2 µA from a 2.5 V supply (95.5 µW) and achieves an input-referred noise floor of 113 µVRMS over a 330 Hz bandwidth, while having an input current range from 1 nA to 20 µA and a noise-limited sensitivity of 56.4 …

The Equity Implications Of Pecuniary Externalities On An Electric Grid, Charles Sims, Gasser G. Ali, J Scott Holladay, Tim Roberson, Chien-Fei Chen, Islam H. El-Haddad

Civil Engineering Faculty Publications

The adoption of rooftop photovoltaic (PV) systems can create upward pressure on retail electricity rates as utilities are forced to spread their fixed costs of generation and transmission across a smaller customer base. Since high-income households are more likely to purchase PV systems, low-income households may be disproportionately impacted by these rate increases. Using a novel combination of agent-based computational economic modeling and a choice experiment of rooftop solar adoption, we show how this pecuniary externality between low- and high-income customers increases low-income electricity bills by 10% in an area with some of the highest poverty rates in the United …

Curvilinear Image Segmentation Using Multiscale Variational U-Net, Rebekah Fortes

LSU New Orleans Theses and Dissertations

Segmentation of curvilinear structures such as water contours, cracks in cement, and vascular networks in biomedical imaging, poses unique challenges due to extreme class imbalance, irregular morphology, low contrast against complex backgrounds, and the need to preserve global connectivity while detecting fine-scale details. We propose a Multiscale Variational U-Net (MSVU-Net) architecture designed specifically to address these challenges. The model integrates multiscale convolutional filters to capture both global context and local detail, while embedding a variational model in the bottleneck layer to enhance structural representation. To mitigate class imbalance and improve fidelity, the network optimizes a hybrid loss function that combines …

Private Sand Mining In The Mississippi River: Sediment Budget And Morphology Implications Between Baton Rouge And Belle Chasse, Louisiana, Brett Mcmann

LSU New Orleans Theses and Dissertations

This analysis examined how private sand mining within the Mississippi River between Baton Rouge, LA and Belle Chasse, LA affected its sand budget from 2004-2012.

Records assembled indicated that private mining removed an annual average of 2.8 million cubic yards of sand. A HEC-RAS one-dimensional sediment transport model was utilized to assess this practice. Three scenarios were simulated: a baseline without mining, conditions reflecting documented mining rates, and a hypothetical case with excessive extraction.

Results suggest that private mining constituted approximately 26 percent of the total sand deficit between Baton Rouge and Belle Chasse. Mining appeared to cause localized changes …

G2pdeep-V2: A Web-Based Deep-Learning Framework For Phenotype Prediction And Biomarker Discovery For All Organisms Using Multi-Omics Data, Shuai Zeng, Trinath Adusumilli, Sania Zafar Awan, Manish Sridhar Immadi, Dong Xu, Trupti Joshi

Biomedical Sciences

Multi-omics data offers rich insights into complex traits across organisms, yet integrating and analyzing these datasets for phenotype prediction and marker discovery remains challenging. Researchers need accessible tools that combine deep learning, hyperparameter optimization, visualization, and downstream analysis in a unified web platform. To address this, we developed G2PDeep-v2, a web-based platform powered by deep learning for phenotype prediction and marker discovery from multi-omics data across a wide range of organisms, including humans and plants. The server provides multiple services for researchers to create deep-learning models through an interactive interface and train these models using an automated hyperparameter tuning algorithm …

Development And Validation Of A Thermal Model For An Electric Vehicle Transmission, Ghazal Rajabikhorasani

Dissertations

This research investigates the thermal behavior of a high-speed electric vehicle (EV) helical gearbox with the goal of improving the prediction accuracy of component temperatures and total power losses under a range of operating conditions. The study focuses on developing a physics-based lumped-parameter thermal network model capable of capturing the main heat generation and dissipation mechanisms within the transmission. The model integrates experimentally validated loss correlations for gears, bearings, seals, and churning, as well as convective and radiative heat transfer paths.

The thermal network model was coded in MATLAB and validated through a series of controlled experiments performed on an …

Enhancing Ad/Adrd Management Through Ihelpcare: A Compliant And Culturally Sensitive Ai-Driven Digital Healthcare Platform, Trisha Bhowmick

Master's Theses

The digital healthcare field is expanding fast, and now it requires platforms that use advanced technology and maintain robust data security and compliance practices. In the present paper, we present the main structure, key methods, and compliance strategies of the digital healthcare system iHelpCare, which, while fully meeting the HIPAA/GDPR requirements, provides health services more accessible, efficient, and inclusive. The proposed platform is powered by AI for personalized care solutions, with the main emphasis on preventive health management and providing tools for people with disabilities.

iHelpCare achieves real-time patient monitoring while securing medical data management and easy communication between patients, …

Llm-Powered Question Answering For Object States In Virtual Reality, Shiyi Ding

Master's Theses

Recent advances in large language models (LLMs) and multimodal large language models (MLLMs) enable natural language–based querying in virtual reality (VR). However, VR environments are highly localized, personalized, and dynamic, making it challenging for general-purpose models to answer environment-specific queries or reason about subtle object state changes. To address these challenges, this thesis develops two systems for 3D question answering in VR.

First, we present RAG-VR, the first retrieval-augmented 3D question-answering system designed for VR. RAG-VR augments an LLM with external knowledge retrieved from a localized knowledge database and includes a pipeline for extracting environmental and user-related information. To improve …

Polydopamine-Coated Magnetic Nanoparticles Data, William G. Pitt

ScholarsArchive Data

This data archive contains raw data and processed data related to research and development of magnetic nanoparticles that adhere to bacteria. This data is the foundation of data in the MS thesis of Bowen Houser, and publications and presentations related to that research effort. Polydopamine-coated magnetic nanoparticles are found to be very adhesive to gram-positive bacteria, and less adhesive to gram-negative bacteria. These data files contain information for S. aureus, S. epidermidis, S. mutans, E. coli, P. aeruginosa, and N. perflava. Some data include the kinetics of capture.