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Captive Model Test For Hydrodynamic Derivatives Of Ship Maneuvering In Regular Head Waves, Pin-Yuan Huang, Zih-Yao Lin, Tsung-Yueh Lin, Fu-En Lee, Yan-Wei Lai

Journal of Marine Science and Technology–Taiwan

The motion of ship in wave can be discussed in seakeeping and maneuvering. In model tests, the former is found by the motion response of waves while the latter requires captive model test to acquire hydrodynamic derivatives. The hydrodynamic derivatives in waves are discovered to be different from those in calm water. To understand better the behavior of maneuverability in waves, maneuvering tests in a wide range of waves are performed in this study. This study presents an experimental investigation into the maneuvering behavior of a container ship in regular waves, covering a wide range of wavelengths from half to …

Measuring The Impact Of 3d Printers On The Health Of Youth, Alexis Kostin, Olla Obeid, Oz Trost

Wetterhahn Science Symposium Posters

3D printers are used more widely than ever before; they can be found in factories, hospitals, and even schools. However, the health effects of the VOCs and UFPs that these machines emit have yet to be fully understood. In collaboration with the University of Nevada, Las Vegas, this study utilizes an Air Gradient One sensor at the Diamond Lab to monitor VOC and UFP emissions before, during, and after 3D printing sessions. By comparing these levels to EPA and CDC safety standards, we aim to quantify the respiratory risks posed to youth.

Numerical And Machine Learning Based Recreation Of Damage Morphologies Of Barely Visible Impact Damage, Oscar A. Valdez

Mechanical and Aerospace Engineering Dissertations

Composite laminates are highly sought after in the aerospace industry as they provide strength without dramatically increasing the weight of manufactured structures. However, composite laminates are susceptible to barely visible impact damage caused by routine activities. This type of damage can easily go unnoticed while significantly reducing the load-carrying capability of the laminate. Current non-destructive evaluation techniques, such as ultrasonic scanning, can reveal the damage footprint but provide no insight into delamination through-the-thickness due to the shadowing effect. Micro-computed tomography offers ply-by-ply damage resolution but is unsuitable for field inspections and is constrained by specimen size. This study aims to …

Set-Theoretic Reachability-Informed Model Predictive Control For Mechanical And Aerospace Systems, Jinaykumar Nitinkumar Patel

Mechanical and Aerospace Engineering Dissertations

Modern mechanical and aerospace systems increasingly operate autonomously in environments characterized by nonlinear dynamics, uncertainty, and safety constraints. In these settings, estimation and control methods based on nominal models and single-point trajectory predictions are usually insufficient to ensure safe and reliable operation. This dissertation uses a set-theoretic perspective, in which the system state, uncertainty, and admissible behavior are described by sets instead of point estimates. The key question is not only what the state is, but what set of states remains consistent with the dynamics, disturbances, control limits, and available measurements. This provides bounded descriptions of uncertainty and supports control …

Experimental Thermal Characterization And Comparison Of Direct Liquid Cooling And Air Cooling For A High-Density Gpu Server Thermal Test Vehicle, Oluwagbolahan Esan

Mechanical and Aerospace Engineering Theses

As the power density of artificial intelligence (AI) and high-performance computing (HPC) servers escalates, air cooling is approaching fundamental scaling limits set by air's low convective heat transfer coefficient and rising parasitic fan power. This thesis presents an experimental comparison of direct-to-chip liquid cooling and air cooling for a high-density GPU server, using a Thermal Test Vehicle (TTV) that emulates the device layout and power-density regime of an 8-GPU SXM5-class baseboard (eight emulated GPU blocks and four NVLink Switch modules). The liquid configuration was tested at 8.8 kW (8.0 kW GPU, 800 W switch) across three Coolant Distribution Unit (CDU) …

Computational Modeling Of Biophysical Transport: Respiratory Drug Delivery And Tissue-Level Physics, Md Tariqul Hossain

Electronic Theses and Dissertations

The nasopharynx, the upper part of the pharynx located at the back of the nose serves as a critical hotspot for initial respiratory infections via inhaled transmission, largely due to the presence of specific surface receptors that pathogens can exploit for cell invasion, combined with a relatively sparse local mucociliary substrate. To enhance the therapeutic efficacy against certain pathogens, such as the SARS and Influenza viruses, it is therefore essential to improve the targeted delivery of drugs to the nasopharynx. This study explores the use of intranasal sprays as a method for drug administration and models the transport of sprayed …

Numerical Investigation Of Injector Location And Equivalence Ratio In A Flame‐Holder Cavity Scramjet, Matthew Sorenson

Electronic Theses and Dissertations

This thesis presents a CFD-based parametric study of injector location and fuel rate in an ethylene-fueled flame-holder cavity scramjet using STAR-CCM+. Simulations are performed for three injector locations (x/D = 18, 36, and 54) and nine equivalence ratios spanning from ϕ = 0.2 to 1.0 in 0.1 increments. The study aims to determine how injector placement and fueling level alter scramjet performance across a broad operating sweep. The results show a clear regime change between ϕ = 0.2 and ϕ ≥ 0.3. At ϕ = 0.2, combustor behavior is weakly sensitive to injector location compared to the higher-fueling cases. For …

Cross-Linking Peg Microgels With Mesoporous Organosilica Nanoparticles To Engineer Microporous Annealed Particle Scaffold Properties, Jonathan M. Zuidema, Alessandro Ajo, Marco Carofiglio, Luisa De Cola

Mechanical Engineering Faculty Publications

Microporous annealed particle (MAP) scaffolds composed of cross-linked microgels are emerging as important biomaterials due to their modular design, high porosity, and large surface area, which allow for highly tailored properties, cellular infiltration, nutrient and waste exchange, and improved drug release characteristics. To further expand on these technologies and enhance their modular design, thiolated mesoporous organosilica nanoparticles (ssMSN-SH), which degrade in response to glutathione, were first cross-linked inside of 4-arm poly(ethylene glycol) maleimide microgels. The microgel size, rheological properties, and payload release characteristics were determined. Hierarchical MAP scaffolds were then created by cross-linking 4-arm poly(ethylene glycol) maleimide microgels with ssMSN-SH. …

Rope Cutting Task Module, Rebecca Usher

Engineering Theses

This project focuses on the design and evaluation of a rope-cutting module for use with robotic platforms developed by New England Robotics Validation and Experimentation Center (NERVE) and the University of Massachusetts Lowell. The system is designed to cut nylon rope using a specialized robotic cutting arm that can be attached to the robot.

The system consists of a module task box that has two pegs that hold two arms to each one. One arm where the spring- mechanism inside of the task module and the second arm the one on top of the box hold the string in place …

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, …

A Framework For Enhanced Circular Product Development With Total Life Cycle Considerations, Gisele Bortolaz Guedes, Fazleena Badurdeen, Ibrahim S. Jawahir

Mechanical Engineering Faculty Publications

Advancing circular product development (CPD) requires design decisions that account for the entire product life cycle, from material sourcing and manufacturing to use and end-of-use (EoU) stages, to ensure enhanced sustainability performance. Existing Product Development Process (PDP) models tend to emphasize isolated phases or perspectives with limited explicit consideration of the total product life cycle. This hinders the systematic embedding of various Circular Economy (CE) strategies during product development. Thus, designers and engineers lack a unified framework to determine when and where critical decisions should be made to effectively incorporate CE strategies such as effective resource selection, extending product use-life, …

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 Unified Finite Element Framework For Cardiac Growth And Remodeling In Mitral Regurgitation Incorporating Fiber Reorientation And Baroreflex, Mohammad Mehri, Jonathan F. Wenk

Mechanical Engineering Faculty Publications

Mitral regurgitation (MR) triggers complex cardiac remodeling responses that alter the structure and function of the left ventricle (LV). While several models have been developed to predict myocardial growth in MR, they often neglect key concurrent adaptive mechanisms that influence both the pattern and severity of LV dilation. This study presents a unified finite element framework to systematically evaluate the individual and combined contributions of fiber reorientation (FR) and baroreflex regulation to LV growth and remodeling, along with the effects of myocardial material property changes associated with the acute and chronic phases of MR. A healthy baseline model and multiple …

Vibration-Based Fault Diagnosis In Industrial Rotating Machinery, Yaman Pandey

All Graduate Theses, Dissertations, and Other Capstone Projects

Unplanned downtime caused by rotating machines results in a significant percentage of the total downtime in manufacturing plants. These downtimes cause significant loss of production time. While preventative maintenance helps minimize lot of these downtimes, it can’t predict the upcoming downtimes and prevent them from occurring. That gave birth to predictive maintenance. While various techniques are used for predictive maintenance, vibration analysis is one of them. In this study, data driven and expert validated diagnosis using vibration analysis for rotary machinery is used. The data is collected from a manufacturing site in Minnesota where 32 rotating assets, including motors and …

Nonlinear Oscillations In Structural Dynamics: Computational Techniques, Data-Driven Tools, And Model Order Reduction, Dalton Stein

Open Access Dissertations

Funding and support for this research was provided by the National Institute for Undersea Vehicle Technology (NIUVT) through the Office of Naval Research (ONR). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research.

The content of this dissertation has been removed because it is CUI.

Influence Of Surface Features On Heat Transfer During Dropwise Condensation Over Superhydrophobic Surfaces In Shear Flow, Shaur Humayun, R. Daniel Maynes, Julie Crocket, Brian D. Iverson

Faculty Publications

This study investigates heat transfer during dropwise condensation (DWC) on superhydrophobic (SH) surfaces in humid air shear flow, emphasizing the effect of increased drop mobility and the influence of surface micro/nanostructure on heat transfer rates. Experiments were conducted on smooth hydrophobic, microstructured SH, nanostructured carbon-infiltrated carbon nanotube (CICNT) surfaces, and two-tiered SH surfaces with both micro and nanostructures. Heat transfer rates were measured under humid air flow rates in the range of 2–4 CFM. Experimental results demonstrate that surfaces with nanostructure (including two-tiered structures) exhibit increased drop mobility and coalescence-induced drop jumping, enhancing drop removal rates and overall heat transfer …