Digital Commons Network^™

Improving Ground Penetrating Radar Calibration For Chloride Assessment In Reinforced Concrete Bridge Decks, Camila Silva Wendland

Engineering Theses

This study investigates how ground penetrating radar (GPR) can be used to estimate chloride content in reinforced concrete bridge decks. Chloride buildup at the rebar level can lead to corrosion and structural damage, but current testing methods are destructive and limited to small sample areas. GPR offers a non-destructive alternative, but interpreting reflection amplitudes is challenging because they are affected by multiple factors, including moisture content and rebar depth. To address this, a simulation-based calibration method was developed. Finite-difference time-domain simulations were used to study how chloride, moisture, and rebar depth influence GPR reflection amplitudes. A depth correction method was …

A Comprehensive Statistical And Regional Analysis Of Lng-Powered Marine Vessels On Ghg Mitigation Strategies Considering Existing Bunkering Stations And Gwp Values, Canberk Hazar, Onur Yuksel, Murat Bayraktar

Journal of Marine Science and Technology–Taiwan

This study aims to quantify and analyse emissions from marine vessels that can operate on liquefied natural gas (LNG) but continue to use conventional fuels, largely due to the limited availability of LNG bunkering stations (BSs) over long distances. Four regions have been identified as having high concentrations of LNG-fueled vessels but limited access to operational BSs: the West Coast of the United States of America (USA), South Africa–Good Hope–Madagascar, Northwest Africa, and Brazil. This selection is based on the geographical distribution of these ships and the existing infrastructure. Hourly greenhouse gas (GHG) emissions have been calculated by considering the …

Characterization Of Tomographic Piv System For Single-Phase Immersion Cooling Applications, Joel Joshua Oommen

Mechanical and Aerospace Engineering Theses

As the rapid expansion of Artificial Intelligence (AI) infrastructure and High-Performance Computing (HPC) pushes power requirements to new heights, traditional air-cooling methods have become inadequate for modern server demands. Consequently, single-phase immersion cooling (SPIC) has emerged as one of the effective and sustainable alternatives, utilizing dielectric fluids to remove heat through direct contact with electronic components. Despite numerous thermal and reliability studies, the complex three-dimensional movement of buoyant thermal plumes around intricate component shapes are not yet fully understood in confined spaces.

This thesis provides a detailed characterization of Tomo-PIV and a component level experimental study of flow patterns in …

Investigation Of Automated 3d Scanning Strategies For Large-Scale Polishing Applications, Casey Egan

Open Access Master's Theses

In automated scanning for industrial refinishing applications, large workpieces often exceed the reach of a single robot base position, and may require the environment to be scanned from multiple locations and stitched to a common reference frame. This thesis compares two robotic scanning workflows for such an object: a full scan that reconstructs the object from a single robot base position, and a segmented scan occurring across multiple simulated robot base positions that are stitched together through fiducial-based localization. The results from both workflows are compared for measurement accuracy of the object's bounding box against known dimensions, position of the …

Scalar Source Localization Using Multi-Sensor Domains Of Dependence In Turbulent Channel Fow, Zejian You, Xiaowei Zhu, Qi Wang

Mechanical and Materials Engineering Faculty Publications and Presentations

Tracking hazardous events such as wildfire smoke, coastal oil spills, or chemical releases in natural environments is complicated by turbulent dispersion and molecular diffusion. This study presents a method to localize pollutant sources rapidly and accurately using infinite time-averaged measurements from a multi-sensor network, leveraging the duality between mean forward and adjoint scalar fields. The forward-adjoint duality states that measurements at the sensor (forward feld) are equal to the adjoint field at the source, providing crucial spatial information about the source. Consequently, the adjoint scalar fields can be interpreted as the domain of dependence for the sensor observations [1, 2]. …

Detecting And Repairing Conflicting Constraints In Co-Trained Physics-Informed Neural Networks For Composite Curing Processes, Cooper J. Evans

Dissertations, Master's Theses and Master's Reports

Composite materials have become a critical component of modern manufacturing, especially in the automotive and aerospace industries. The curing process for these composites has been modeled using a variety of partial differential equations representing the heat transfer and composite curing kinetics. Optimizing the applied temperature profile is critical for maximizing the efficiency and capacity of composite part manufacturers. Constraints must be placed on the inputs and outputs of the model, including but not limited to, the applied temperature profile, part temperature, and final degree of cure. Conflicting sets of constraints are easy to unknowingly impose due to the highly coupled …

Torque-Based Detection And Isolation Of Bucket-Specific Load Variations In A Continuous Bucket Ladder Excavator, Mason R. Krause

Dissertations, Master's Theses and Master's Reports

Understanding how cutter geometry, material, and operating conditions influence excavation performance is critical for the design of lunar surface systems operating in regolith environments. This work presents a torque-based methodology for detecting and quantifying bucket-specific load variations in a continuous bucket ladder excavator. A nine-bucket excavator was constructed to record drivetrain torque while operating in a regolith simulant over multi-day test periods. Each bucket featured a unique combination of cutting edge material and geometry. A method was developed to separate the continuous torque data into individual excavation events, enabling identification of individual bucket interactions. Analysis of the resulting event-based dataset …

Analytical Study Of Transient Mixed Convective Radiative Jeffrey Fluid Flow With Diffusion–Thermo And Chemical Reaction, V. Sathiya, R. Vijayaragavan, B. Rushi Kumar

Mansoura Engineering Journal

This research examines the behavior of unsteady mixed convective radiative Jeffrey fluid flow over a permeable moving plate with a diffusion thermo effect. The study incorporates multiple factors, including aligned magnetic fields, heat generation, radiation, and chemical reactions. The behavior of Jeffrey fluid under these combined conditions is particularly relevant to the design of efficient heat exchangers, MHD generators, and cooling systems for electronic components. A regular perturbation technique was employed to solve the governing equations, yielding distributions for velocity, temperature, and species concentration. These solutions enabled the derivation of expressions for skin friction, Nusselt number, and Sherwood number. Through …

Gradient-Based, Post-Optimality Sensitivity Analysis With Respect To Parameters Of State Equations, Gene Hou, Jonathan Degroff

Mechanical & Aerospace Engineering Faculty Publications

Design optimization is a computational tool that can enable a designer to investigate the effectiveness of a design concept in an organized format. However, this design process requires the design variables, constraints, and objective function to be properly defined and expressed in mathematical forms. Post-optimality analysis thus becomes a necessary step to investigate different variations in the problem formulation and parameters to ensure that optimization produces a stable and trustworthy outcome. One efficient way to achieve this aim is to compute the local derivative of the optimized objective function with respect to the optimization problem parameters, such as bounds on …

Uncertainty-Aware Estimation, Planning, And Control For Tracking Multiple Drifting Patches In Flow Fields, Daniel O. Akanji, Krishnanand N. Kaipa, Cong Wei

Mechanical & Aerospace Engineering Faculty Publications

In this study, we present a replay-based framework for uncertainty-aware persistent tracking of multiple advected surface patches using an autonomous marine vehicle operating in spatiotemporal-varying currents. The method combines three components: local flow estimation, covariance-aware patch-boundary propagation with intermittent boundary fusion, and mission-level scheduling over multiple patches. Each patch is represented by a polygonal boundary, whose vertices are propagated through the estimated flow field while carrying per-vertex covariance, thereby quantifying uncertainty growth during advection. A flow-aware gain-scheduled linear quadratic regulator (LQR) was designed to shape the desired surge speed to take advantage of favorable currents. When the vehicle services a …

Influence Of Motion Artifacts On Instantaneous Frequency Based Heart Rate Variability Of Arterial Pulse Signals Measured By A Tactile Sensor: An Analytical Study, Mamun Hasan, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

Objective: Heart rate variability (HRV), quantified via the instantaneous frequency (IF) of arterial pulse signals, is a key indicator of cardiovascular (CV) regulation. This study presents a theoretical and experimental investigation of how motion artifacts (MA) influence IF-and thus HRVmeasured with a tactile sensor, emphasizing underlying mechanisms rather than population-level validation. Approach: Building on a previously developed single-degree-of-freedom (SDOF) model of the tissue-contact-sensor (TCS) stack between the sensor and the artery, MA is represented as low-frequency baseline drift and time-varying system parameters (TVSP) of the TCS stack. Analytical expressions quantify the effect of MA on the IF of each harmonic …

Radical-Based Oxidative Pretreatment Enhances Biofuel Production From Lignocellulosic Biomass Via Hydrothermal Liquefaction, João Vitor Dos Santos, Louis C. Bondurant, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The sustainable production of biofuels from lignocellulosic biomass is a central goal in the transition to low-carbon energy systems. However, hydrothermal liquefaction (HTL), a promising thermochemical conversion pathway, is constrained by the high oxygen content and complex aromatic structure of lignin, which lowers bio-oil quality. Here, we used a model system of brown-rot-degraded white oak (Quercus alba) to test whether radical-based oxidative pretreatment could enhance HTL performance by converting lignin into more aliphatic intermediates. Oxidation was performed under simulated Fenton conditions using fixed Fe(II) (60 ppm) and two hydrogen peroxide concentrations (3 and 8 M), resulting in extensive lignin depolymerization …

Autonomous Coupler Alignment Using Position-Based Visual Servoing In A Ros~2 Framework, Nickolas Giffen

Graduate Research Theses & Dissertations

As robotic arms are becoming increasingly common alongside humans as collaborative robots, their high precision in motion enables tasks to be performed at significantly higher speeds with reduced disruption in the environment. The Fermi National Accelerator Laboratory is exploring this application by incorporating a UR16e from Universal Robots in a cleanroom setting during assembly of couplers to superconducting radio frequency cavities as part of the PIP-II project. The goal of the robotic assembly process is to precisely position the UR16e robot so that the coupler flange, mounted on the robot’s end-effector, is accurately aligned with and pressed against the cavity …

Gaussian Process Regression–Based Uncertainty Quantification For Unmanned Aircraft System Traffic Management And Advanced Air Mobility Applications, Aakarshan Khanal

Mechanical and Aerospace Engineering Dissertations

Uncertainty quantification has gained significant attention in recent years as a research area in dynamical systems. Mathematical representations of the physical system, combined with an understanding of model uncertainties, enable the propagation of uncertainty in temporal space, which allows us to make informed decisions. However, what if the true dynamics of the system is unknown or too complex to define explicitly? In such cases, the system’s behavior can instead be inferred or learned from observed input–output data rather than from an analytical or physics-based model. To this end, this dissertation focuses on developing a data-driven framework for nonparametric dynamics modeling, …

Stoichiometry-Controlled Surface Reconstructions In Epitaxial Abo3 Perovskites For Sustainable Energy Applications, Habib Rostaghi Chalaki, Ebenezer Seesi, Gene Yang, Mohammad El Loubani, Dongkyu Lee

Faculty Publications

ABO₃ perovskite oxides are a versatile class of materials whose surfaces and interfaces play essential roles in sustainable energy technologies, including catalysis, solid oxide fuel and electrolysis cells, thermoelectrics, and energy-relevant oxide electronics. The interplay between point defects and surface reconstructions strongly affects interfacial stability, charge transport, and catalytic activity under operating conditions. This review summarizes recent progress in understanding how oxygen vacancies, cation nonstoichiometry, and electronic defects couple to atomic-scale surface rearrangements in representative perovskite systems. We first revisit Tasker’s classification of ionic surfaces and clarify how defect chemistry provides compensation mechanisms that stabilize otherwise polar or metastable …

Guitar Amplifier Directivity, Rachel C. Edelman, Brian E. Anderson, Samuel D. Bellows, Timothy W. Leishman

Directivity

No abstract provided.

A Mold Mating Surface Temperature Monitoring System For Injection Molding Using Infrared Thermography And Mahalanobis Distance, Yoshio Fukushima, Makoto Fukushima, Sho Shibuya, Keigo Kudo, Yuta Abe

ASEAN Journal on Science and Technology for Development

In plastic injection molding, minimizing defects is crucial for sustainable and stable manufacturing because resin behavior and molding conditions fluctuate due to variations in material lots, seasonal shifts, and factory environmental factors such as temperature and humidity. Among various process parameters, mold temperature　- specifically the mold mating surface temperature immediately after part ejection-　 plays a critical role in mitigating these variations and maintaining consistent product quality. However, embedding conventional sensors into the mating surface is structurally difficult. While non-contact infrared thermography is an effective alternative, shiny metallic mold surfaces suffer from low emissivity, leading to inaccurate readings. Furthermore, high-end …

Castrip Process Technology: Non-Grain Oriented (Ngo) Si Steels Extension And Carbide-Free Bainitic (Cfb) For Flat Products, Naram Naidu Meesala

Masters Theses

"This research explores the development of advanced steel grades manufactured through Castrip® twin-roll thin strip casting technology, with particular attention to non-grain-oriented electrical Si-Steels (NGOES) and carbide-free bainitic (CFB) steels. The Castrip® process offers a near-net-shape route for producing thin steel strips, which greatly decreases the number of processing stages, lowers energy demand, and reduces carbon dioxide emissions when compared with traditional steel production methods.

In the NGOES part of the study, several industrial Fe–Si steel compositions were cold rolled to final thicknesses ranging from 0.35 mm to 0.15 mm. These materials were then exposed to short-duration continuous annealing at …

Critical Parameters Controlling Oxide Scale Formation And Hydro-Descaling Efficiency During Steelmaking, Tochukwu Princewill Ojiako

Doctoral Dissertations

In modern steelmaking, cast slabs are exposed to high-temperature oxidizing environments during secondary cooling, reheating, and hot rolling, resulting in the formation of multilayer oxide scales on the steel surface. These scales interact with mold-flux residues originating from the casting process (CC). The morphology, chemistry, and adhesion of oxide scale strongly influence its removability during high-pressure hydraulic descaling and ultimately determine the surface quality of hot-rolled products. However, the mechanistic relationship between oxide scale evolution, scale-steel interfacial structure, and hydraulic descaling performance remains poorly understood.

This dissertation investigates oxide scale formation, modification, and removal in low-carbon thin-slab steels produced by …

Manufacturing And Performance Evaluation Of Carbon/Epoxy Laminated Composites Cured Using Single- And Six-Magnetron Microwave Applications, Nayan Pundhir

Doctoral Dissertations

Microwave curing is fast, energy-efficient, and a viable alternative to conventional thermal curing processes. It has been widely adopted for processing carbon fiber-reinforced polymer (CFRP) composites because the high electrical conductivity of carbon fibers enables strong microwave coupling, leading to rapid volumetric heating and reduced energy consumption. The aim of this study is to investigate the use of microwave curing for manufacturing CFRP composites. IM7/Cycom 5320-1 unidirectional prepreg was utilized to fabricate laminated composites in two thickness ranges: 16-layer laminates (2.5 mm thickness) and 64-layer laminates (9.2 mm thickness). Two lay-up configurations were examined: symmetric cross-ply and quasi-isotropic. Different curing …

Simulation And Characterization Of Fuel Cell System Incorporated Internet Of Things, Ahmad N. Alhjouj

Mechanical Engineering Theses

Small air-cooled proton exchange membrane fuel cell (PEMFC) systems are increasingly relevant for portable and distributed applications, yet practical modeling and monitoring methods remain limited: high-fidelity physics-based models are too costly for real-time use, while purely data-driven models discard physical interpretability. This thesis develops an experimentally grounded gray-box framework for the characterization, reduced-order modeling, and IoT-enabled monitoring of a small hydrogen PEMFC system. A low-order nonlinear state-space model couples an electrochemical voltage layer to a lumped thermal layer, with parameters identified in stages using self-adaptive differential evolution. Identifiability analysis shows that static loss parameters are well constrained, while dynamic parameters …

Computational Study Of Rotating Detonation Combustors, Aditya Balasubramaniam

Mechanical and Aerospace Engineering Theses

Rotating detonation combustors (RDCs) are pressure-gain combustion devices that sustain one or more continuously rotating detonation waves, offering potential thermodynamic and performance advantages over conventional deflagration-based systems. Their behavior depends strongly on combustor geometry and operating conditions. Understanding these effects is therefore essential for the design and optimization of practical RDCs. Accordingly, this thesis numerically investigates annular RDCs with two primary objectives: (1) to evaluate the effects of propellant mass flux and (2) to assess the influence of annular width on detonation-wave dynamics and combustor performance.

A finite-volume framework is used to solve the compressible reactive Euler equations with hydrogen–air …

Electron Beam Irradiation Effects On Bulk Metals: A Comparative Study Of Polycrystalline Versus Single-Crystalline Structures, A. A. Elmustafa, N. A. Sultana, A. H. Al-Allaq, M. Ojha, Y. S. Mohammed, J. Vennekate, H. Baumgart

Mechanical & Aerospace Engineering Faculty Publications

This study investigates the effects of electron beam (e-beam) irradiation on the mechanical and structural properties of eight bulk metallic samples, comprising both polycrystalline (PC) and single-crystalline (SC) forms of Ni, Cr, V, and Ti. These metals were evaluated as potential candidates for beam exit windows in high-power (MW-class) particle accelerators. The primary objective is to identify metals capable of withstanding the conditions of high-power/MW-class e-beam accelerators and serve effectively as exit windows. Selection criteria were based on each metal’s intrinsic properties, power dissipation capability, and irradiation-induced changes in mechanical behavior, including hardness, elastic modulus, and defect density. Comprehensive characterization …

Field-Assisted Post-Processing Of Cold-Sprayed Pure Copper, Alan Hensley

Theses and Dissertations--Mechanical and Aerospace Engineering

The properties of materials processed through cold spray, and many other AM processes, are non-uniform and unpredictable. In most cases, post-processing is required to achieve desired properties and better uniformity. In cold spray, the typical method is an annealing heat treatment (AHT), which can improve bond strength, reduce porosity, and restore ductility, among other effects. AHT alone, however, is unable to completely remedy any of the unfavorable properties. In addition, long treatments at high temperatures are often needed for satisfactory results. This increases energy consumption and extends production times for products made by the process. For these reasons, numerous investigations …

Multiphysics Transport In Porous Thermal Protection Systems: Experimental Characterization Of Gas Permeability And Radiative Properties, Yejajul Hakim

Theses and Dissertations--Mechanical and Aerospace Engineering

Porous thermal protection systems (TPS) used in hypersonic vehicles exhibit coupled gas and radiative transport across multiple regimes and length scales. Accurate performance prediction requires reliable characterization of permeability, slip-flow behavior, and radiative transport properties, particularly for low-permeability and charred materials where existing data are limited. This dissertation presents experimental methods for characterizing multiphysics transport in porous TPS materials. A modular flow system was developed to measure permeability and slip behavior in both virgin and charred materials under relevant environments. A transient pressure decay method enables accurate permeability estimation in low-permeability regimes and provides insight into effective pore structure. Results …

Reciprocity-Based Transfer Function Techniques For Acoustic Source Reconstruction, Spring Isolator Characterization And Structural Damping Assessment, David Pum Thian Lal Paite Neihguk

Theses and Dissertations--Mechanical and Aerospace Engineering

Reciprocity implies that a system responds identically when the source and receiver positions are interchanged. This dissertation applies this principle to address three practical challenges in noise and vibration characterization, where conventional approaches are limited by inaccessible interfaces, constrained excitation conditions, or metrics that do not fully capture vibroacoustic behavior.

The first study develops and validates an inverse method to characterize ducted acoustic sources using acoustic free velocity. Acoustic reciprocity is applied to simplify transfer function measurements. The method is extended to large cross-section ducts, where the source is reconstructed as a collection of point sources along a plane. Validation …

Process-Guided Learning Via Data-Driven Modeling And Controller Synthesis, Benton Clark

Theses and Dissertations--Mechanical and Aerospace Engineering

This work introduces process-guided learning, a framework in which process characteristics and learning algorithms are combined in the modeling process of engineering applications with the aim of uniting traditional and data-driven modeling and control techniques. Traditional engineering methods using simplified analytic models fail to capture the increasing complexities of engineering problems with sufficient accuracy to achieve modern requirements. More advanced modeling and control techniques using high-fidelity models often produce a computational burden that is infeasible for real-time solutions. Data-driven modeling offers a simple and flexible algorithm for producing real-time capable, high-fidelity models, but naive implementations lack the physical constraints of …

Physics-Constrained Generative Adversarial Networks For Dimensionality Reduction In Optimization, Samuel Sisk, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft make a unique form of urban air mobility due to their low noise, zero emission, and precision control. To maximize efficiency, high-fidelity simulation-based multidisciplinary design optimization discovers the optimal balance among subsystems within an eVTOL. However, conventional multidisciplinary design optimization is computationally intensive due to excessive high-fidelity model evaluations. Moreover, complex nonlinear constraints deteriorate optimization efficiency and convergence. While surrogate models enable efficient design optimization, surrogate modeling suffers in large-scale applications and surrogate-based optimization still has to deal with nonlinear constraints. To address these challenges, the authors' previous work proposed physics-constrained generative adversarial …

Optimal Takeoff Trajectory Prediction Of Electric Drones Based On A Fully Automated Optimal Experimental Design Method, Jiachen Wang, Dheeraj Paramkusham, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft is attracting great interest as a viable solution to promote urban aerial mobility with promising flexibility as well as emission reductions. However, the low specific energy of the current battery is still a strong constraint on the range and endurance of eVTOL flights, especially considering the significant power demands during the takeoff process. Engineering design optimization permits promising solutions for the minimum takeoff energy consumption but can be computationally intensive due to iteratively evaluating simulation models. Surrogate-based design optimization is efficient but still relies on optimization iterations which prohibit real-time decision-making. To fill …

Atomized Oxidative Polymerization As A 3d Printing Platform For Binder-Free, Bulk Conductive Polymer Architectures, Tazdik Patwary Plateau, Hiep Pham, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Translating the ultrahigh intrinsic conductivity of conjugated polymers into bulk 3D architectures remains a formidable challenge due to the fundamental dichotomy between rheological printability and electronic purity. Existing strategies necessitate a compromise: solution-processing requires insulating binders that degrade charge transport, while binder-free vapor-phase polymerization (VPP) is kinetically confined to surface-limited thin films by diffusion constraints. Here, we introduce atomized oxidative polymerization (AOP), a manufacturing paradigm that overcomes these kinetic barriers via active, layer-by-layer monomer atomization. This approach ensures stoichiometric reaction conditions throughout the printed volume, driving a structural transition toward highly conductive quinoid-dominant chains with enhanced π-π stacking. The resulting …