Engineering Commons^™

Analysis Of An Electrospray Thruster With A Concave Propellant Meniscus, Adam Nicholas Huller

Masters Theses

The low thrust, high specific impulse, and low mass of electrospray thrusters (ETs) make them ideal for maneuvering nanosatellites, especially with the new requirement to deorbit a satellite within five years of completing its mission. These innovative thrusters use electrohydrodynamic principles of electrospray (ES) to provide thrust. These principles have been subject to much research over the past decade, though much more research is needed to fully understand the underlying physics of these thrusters. The first part of this study establishes a procedure for analyzing the theoretical thrust performance of an ET, by using propellant properties and well-documented ES scaling …

Preparation Of The Ej301d, A Deuterated Liquid Organic Scintillation Detector, For Spectroscopy Of Fast And High Energy Neutrons, Albert Du

Masters Theses

The focus of this research is on the preparation of a deuterated organic scintillation detector for fast and high energy neutron spectroscopy. The underlying physics of organic scintillation detectors, the process in which a neutron undergoes interaction with the detector material, as well as the readout and data processing procedure is introduced.

For methodology, a comprehensive setup of an EJ301-D deuterated organic scin- tillation detector is detailed. This includes algorithmic development for three distinct purposes. Firstly, it involves the creation of iterative unfolding algorithms, specif- ically the GRAVEL and Maximum Likelihood Expectation-Maximization (MLEM)

algorithm. The second development is conformal binning …

Nonlinear Finite Element Model For Functionally Graded Porous Circular/Annular Micro-Plates Under Thermal And Mechanical Load, Enrique Nava Munoz

Masters Theses

A nonlinear finite element model for micro circular/annular plates under thermal and mechanical loading is developed using a third order shear deformation theory. In the kinematic assumptions, the change of plate thickness is allowed and no transverse shear strains are considered on the top and bottom surfaces. A power-law distribution is utilized to account for variations of two constituents through the thickness of the plate. Three different types of porosity distributions are considered. The strain gradient effect in micro scale structures is considered using the modified couple stress theory. The dynamic version of the principle of virtual displacements is used …

Advancing Winter Weather Adas: Tire Track Identification And Road Snow Coverage Estimation Using Deep Learning And Sensor Integration, Parth Kadav

Masters Theses

No abstract provided.

Surface Location Error In Robotic Milling: Modeling And Experiments, Richard Henry Swan Jr.

Masters Theses

Robotic milling offers new opportunities for discrete part manufacturing as an alternative to milling using large conventional machine tools. The advantage of industrial robots is their large work volume, configurability, and comparatively low cost. However, robots are significantly less stiff than conventional machine tools, which can lead to poor surface finish, low machining accuracy, and low material removal rates. The purpose of this research is to predict the geometric errors, or surface location errors, that occur in a robotic mulling tool path, validate these predictions with machining tests, and compensate these errors by tool path modification. Compared with conventional machine …

A Case Study In Cmos Design Scaling For Analog Applications: The Ringamp Ldo, Steven Corum

Masters Theses

As CMOS process nodes scale to smaller feature sizes, process optimizations are made to achieve improvements in digital circuit performance, such as increasing speed and memory, while decreasing power consumption. Unfortunately for analog design, these optimizations usually come at the expense of poorer transistor performance, such as reduced small signal output resistance and increased channel length modulation. The ring amplifier has been proposed as a digital solution to the analog scaling problem, by configuring digital inverters to function as analog amplifiers through deadzone biasing. As digital inverters naturally scale, the ring amplifier is a promising area of exploration for analog …

Developing A Flexible System For A Friendly Robot To Ease Dementia (Fred) Using Cloud Technologies And Software Design Patterns, Robert James Bray

Masters Theses

In this work, we designed two prototypes for a friendly robot to ease dementia (FRED). This affordable social robot is designed to provide company to older adults with cognitive decline, create reminders for important events and tasks, like taking medication, and providing cognitive stimulus through games. This project combines several cloud technologies including speech-to-text, cloud data storage, and chat generation in order to provide high level interactions with a social robot. Software design patterns were employed in the creation of the software to produce flexible code base that can sustain platform changes easily, including the framework used for the graphical …

Uncertainty Quantification Framework For Design Optimization, Austin Ryan Williams

Masters Theses

Difficulty to obtain neutron sources of interest have driven the need for optimization
techniques to tailor a neutron generator as a replacement. A proposed solution uses
off-the-shelf neutron sources coupled with an energy-tuning assembly to mimic the
source of interest (i.e. AmLi, AmBe, thermonuclear fission spectra, etc.). These
energy-tuning assemblies have been designed with complex optimization algorithms
coupled with Monte Carlo simulations. These new system surrogate designs often
do not have an experimental counterpart for validation and comparison, and lack
non-statistical uncertainties. This work aims to improve confidence in the predictions
by providing a tool for fast uncertainty quantification to …

Modular Composite Sandwich Structures For Thermal And Structural Retrofitting Of Existing Buildings, Marc Al Ghazal

Masters Theses

Around 40% of global energy consumption and 30% of worldwide carbon dioxide (CO2) emissions are attributed to buildings. Most of this consumption is dedicated to ensuring thermal comfort. The goal of this research was to develop and field validate retrofit solutions to improve the energy efficiency of buildings. Exterior cladding panels were designed and tested to ensure adequate thermal and structural performance. Sandwich panels (glass fibers reinforced polymer (GFRP) skins and polymeric foam cores) were fabricated using the vacuum assisted resin transfer molding (VARTM) process. Extruded polystyrene (XPS) and polyurethane (PU) foams were compared as core materials through a series …

Optimizing Channel Formation In Peg Maleimide Hydrogels, Bakthavachalam Kannadasan

Masters Theses

Blood vessels including the arteries, veins, and capillaries are a critical and indispensable component of various organisms. Some studies estimate that if all the blood vessels present in our body are arranged in line, they would amount to a total length of approximately 60,000 miles. This distance is enough to circle the world two and a half times! In addition to being all pervasive, blood vessels perform certain key functions such as delivery of oxygen and nutrients to various tissues in the body. They also assist in the spread of diseases such as cancer. Therefore, it is important to study …

Machine Learning Modeling Of Polymer Coating Formulations: Benchmark Of Feature Representation Schemes, Nelson I. Evbarunegbe

Masters Theses

Polymer coatings offer a wide range of benefits across various industries, playing a crucial role in product protection and extension of shelf life. However, formulating them can be a non-trivial task given the multitude of variables and factors involved in the production process, rendering it a complex, high-dimensional problem. To tackle this problem, machine learning (ML) has emerged as a promising tool, showing considerable potential in enhancing various polymer and chemistry-based applications, particularly those dealing with high dimensional complexities.

Our research aims to develop a physics-guided ML approach to facilitate the formulations of polymer coatings. As the first step, this …

Analog Cancellation Of A Known Remote Interference: Hardware Realization And Analysis, James M. Doty

Masters Theses

The onset of quantum computing threatens commonly used schemes for information secrecy across wireless communication channels, particularly key-based data-level encryption. This calls for secrecy schemes that can provide everlasting secrecy resistant to increased computational power of an adversary. One novel physical layer scheme proposes that an intended receiver capable of performing analog cancellation of a known key-based interference would hold a significant advantage in recovering small underlying messages versus an eavesdropper performing cancellation after analog-to-digital conversion. This advantage holds even in the event that an eavesdropper can recover and use the original key in their digital cancellation. Inspired by this …

Thermal Conductivity And Mechanical Properties Of Interlayer-Bonded Graphene Bilayers, Afnan Mostafa

Masters Theses

Graphene, an allotrope of carbon, has demonstrated exceptional mechanical, thermal, electronic, and optical properties. Complementary to such innate properties, structural modification through chemical functionalization or defect engineering can significantly enhance the properties and functionality of graphene and its derivatives. Hence, understanding structure-property relationships in graphene-based metamaterials has garnered much attention in recent years. In this thesis, we present molecular dynamics studies aimed at elucidating structure-property relationships that govern the thermomechanical response of interlayer-bonded graphene bilayers.

First, we present a systematic and thorough analysis of thermal transport in interlayer-bonded twisted bilayer graphene (IB-TBG). We find that the introduction of interlayer C-C …

Mining High Impact Combinations Of Conditions From The Medical Expenditure Panel Survey, Arjun Mohan

Masters Theses

The condition of multimorbidity — the presence of two or more medical conditions in an individual — is a growing phenomenon worldwide. In the United States, multimorbid patients represent more than a third of the population and the trend is steadily increasing in an already aging population. There is thus a pressing need to understand the patterns in which multimorbidity occurs, and to better understand the nature of the care that is required to be provided to such patients.

In this thesis, we use data from the Medical Expenditure Panel Survey (MEPS) from the years 2011 to 2015 to identify …

Improving Irrigant Flow Characteristics For Enhanced Root Canal Therapy: A Numerical Study, Bibek Banjaday

Masters Theses

This numerical study investigates the flow characteristics within a root canal during a manual endodontic treatment. To underscore the difference in root canal geometry, a simplified root canal (frustum of a cone) and a more complex (realistic) root canal geometry were considered. The needle utilized in all simulations is a side-vented 30G KerrHaweIrrigation Probe, KerrHawe SA, Bioggio, Switzerland. For both root canal geometries, the effect of variation of fluid inlet velocity, needle insertion depth, and needle tilt angle on flow characteristics was examined via velocity contours, turbulent intensity, wall shear stress, and streamline and vector plots. The fluid was Sodium …

Enhancing Human Key Point Identification: A Comparative Study Of High-Resolution Vicon Dataset And Coco Dataset Using Bpnet, Bibash Lama

Masters Theses

Accurately identifying human key points is crucial for various applications, including activity recognition, pose estimation, and gait analysis. This study presents a high-resolution dataset created using the VICON motion capture system and three differently oriented 2D cameras, that can be used to train different neural networks for estimating the 2D key joint positions of the person from the 2D images or videos. The participants in the study included 25 healthy adults (17 males and 8 females) performing normal gait movements for about 2 to 3 seconds. The VICON system captured 3D ground truth data, while the three 2D cameras collected …

A Feasibility Study Of A Wearable Health Monitoring Device Powered By Thermoelectric Generators, Sarah Schneider

Masters Theses

Implementation of thermoelectric generators (TEGs) as a power source for embedded systems has increased with the push toward alternative and renewable energy sources. Thermoelectric generators produce electrical energy from thermal energy through the Seebeck effect. The Seebeck effect is a phenomenon seen when a temperature difference at a joint of two different metals generates a DC current and electromotive force [1]. This has made TEGs desirable for embedded system applications because it would allow for extended wireless operation. TEGs are based on solid-state technology which means they do not consist of any moving parts which reduces wear and tear with …

Analyzing The System Features, Usability, And Performance Of A Containerized Application On Cloud Computing Systems, Anoop Abraham

Masters Theses

This study analyzed the system features, usability, and performance of three serverless cloud computing platforms: Google Cloud’s Cloud Run, Amazon Web Service’s App Runner, and Microsoft Azure’s Container Apps. The analysis was conducted on a containerized mobile application designed to track real-time bus locations for San Antonio public buses on specific routes and provide estimated arrival times for selected bus stops. The study evaluated various system-related features, including service configuration, pricing, and memory & CPU capacity, along with performance metrics such as container latency, Distance Matrix API response time, and CPU utilization for each service. Easy-to-use usability was also evaluated …

Fingerprinting For Chiplet Architectures Using Power Distribution Network Transients, Matthew G. Burke

Masters Theses

Chiplets have become an increasingly popular technology for extending Moore's Law and improving the reliability of integrated circuits. They do this by placing several small, interacting chips on an interposer rather than the traditional, single chip used for a device. Like any other type of integrated circuit, chiplets are in need of a physical layer of security to defend against hardware Trojans, counterfeiting, probing, and other methods of tampering and physical attacks.

Power distribution networks are ubiquitous across chiplet and monolithic ICs, and are essential to the function of the device. Thus, we propose a method of fingerprinting transient signals …

The Current State Of Practice Of Building Information Modeling, Kevin P. Brooks

Masters Theses

Building Information Modeling (BIM) has become extremely prominent in the construction industry in the past twenty years. It serves as a digital repository that can, when used to its fullest potential, combine all aspects of designing, building, and managing a structure in one place, alongside all the data produced in those processes. The construction industry has to date struggled to increase productivity alongside similar fields, such as the manufacturing industry, though the construction industry generally has far more stakeholders on one project than the manufacturing industry. Further, building designs are becoming more complex while project schedules are becoming tighter. As …

Design And Fabrication Of A Trapped Ion Quantum Computing Testbed, Christopher A. Caron

Masters Theses

Here we present the design, assembly and successful ion trapping of a room-temperature ion trap system with a custom designed and fabricated surface electrode ion trap, which allows for rapid prototyping of novel trap designs such that new chips can be installed and reach UHV in under 2 days. The system has demonstrated success at trapping and maintaining both single ions and cold crystals of ions. We achieve this by fabricating our own custom surface Paul traps in the UMass Amherst cleanroom facilities, which are then argon ion milled, diced, mounted and wire bonded to an interposer which is placed …

Improving Energy Efficiency Of School Buildings With Solar-Assisted Cooling For The Maldives, Ahmed Fathhee

Masters Theses

Anthropogenic activities are responsible for the impact of global climate change because of burning fossil fuels releasing harmful gases into the environment. As a result, the global temperature has risen about 1.18 °C since 1880, causing the global sea level to rise by 178 mm over the past century. This is a threat to countries that are closer to the ocean, especially the low-lying countries such as the Maldives. It is predicted if the sea level keeps rising, most of these islands could be below sea level by 2030.

The Maldives has a tropical climate requiring cooling to achieve thermal …

The Effects Of Hurricane Wind Field Characteristics On Wind Blade Loads, Michael S. Tsai

Masters Theses

Over recent years, offshore wind energy has been growing around the world. This necessitates placing wind turbines directly in or near the oceans where hurricanes can be. Previous research has suggested that hurricane wind veer and direction change can have adverse loading effects on the turbine. Such effects can create damage to the blade or worsen existing ones. Currently, there is no known design standard for addressing wind veer and direction change specifically from hurricanes. Quantifying the loading contribution from these phenomena is not abundant either.

This thesis seeks to demonstrate a proposed procedure for defining design veer profiles and …

Post-Fire Damage Inspection Of Concrete Tunnel Structures, James Viglas

Masters Theses

In general, tunnels are designed with an abundance of safety regarding structural integrity, however, there can be uncertainty related to structural performance after a fire event. The residual condition of a tunnel after a fire is dependent on fire intensity and duration. The goal of this study is to correlate visual and material characteristics of structural and non-structural components of tunnels with fire temperature and exposure time. This can be further related to the residual capacity of structural members in a tunnel, providing insight into safety and overall functionality. Experimental results show that the visual response of materials with heat …

Sel4 On Risc-V - Developing High Assurance Platforms With Modular Open-Source Architectures, Michael A. Doran Jr

Masters Theses

Virtualization is now becoming an industry standard for modern embedded systems. Modern embedded systems can now support multiple applications on a single hardware platform while meeting power and cost requirements. Virtualization on an embedded system is achieved through the design of the hardware-software interface. Instruction set architecture, ISA, defines the hardware-software interface for an embedded system. At the hardware level the ISA, provides extensions to support virtualization.

In addition to an ISA that supports hypervisor extensions it is equally important to provide a hypervisor completely capable of exploiting the benefits of virtualization for securing modern embedded systems. Currently there does …

Boundary Layer Measurements On The Bolt Ii Geometry Using Pressure And Temperature Sensitive Paints, Jacob Gaetano Butera

Masters Theses

Hypersonic vehicles are subjected to an extreme aerothermodynamic environment dominated by intense thermal loading which is amplified further when the local boundary layer state transitions from a laminar to a turbulent state. Due to weight and complexity considerations, it is not feasible to incorporate thermal protection systems (TPS) over an entire hypersonic body. Therefore, it is critically important to identify and predict where the boundary layer will undergo transition such that the thermal protection system can be focused on the most at-risk areas. This work attempts to observe boundary layer transition on the Boundary Layer Transition (BOLT) II flight test …

A Computational Analysis Of Hypersonic Store Separations, Ryan C. Savery

Masters Theses

Many current hypersonic vehicles involve shrouds, fairings, boosters, or ejectable payloads separating during flight. It is imperative that they do not strike each other after separation as this typically results in damage or loss of vehicle. This requires a detailed understanding of the flow features involved such as shock waves, expansion waves, shock reflections, and shock wave boundary layer interactions influencing the vehicles' attitude and trajectory. Experimental and flight tests of these scenarios are costly and need massive infrastructure which require difficult measurement techniques to characterize the flow field. Alternatively, numerical simulations can provide accurate, low-cost, and efficient predictions of …

Flow Control Over An Airfoil Using Synthetic Jet, Satyam Anil Mistry

Masters Theses

In this study, the unsteady, turbulent flow over NACA 0015 was analyzed using synthetic jets. The study focused on applying the numerical method using the commercial CFD solver Ansys Fluent. The synthetic jet simulation was carried out for Re = 896,000 for two angles of attack: 10 and 14 degrees. The optimal jet amplitude and jet frequency were determined from a range of amplitudes of 2.0 to 4.0 and frequencies of 0.4 Hz to 1.2 Hz while the jet location, jet angle, and jet width were fixed. The results showed that for both angles, the optimal amplitude and frequency were …

Refractory High-Entropy Alloys: Design, Fabrication, Characterization, And Nanoparticle Synthesis, John Hutson Whitlow

Masters Theses

High-Entropy Alloys have been a highly researched area of metals ever since their introduction in 2004 by Brian Cantor and Jien-Weh Yeh. In the continued research of High-Entropy Alloys (HEAs), a specific area concerning Refractory High-Entropy Alloys (RHEAs) has emerged for their high-temperature applications. Although RHEAs have maintained high strength and toughness at high temperatures, their low ductility still needs to be addressed. A dataset was created to find correlations between various characteristics of RHEAs and their composition. A set of seven compositions were selected and fabricated. Mechanical tests were run on the seven compositions, and a proposal was written …

In Situ Process Monitoring And Machine Learning Based Modeling Of Defects And Anomalies In Wire-Arc Additive Manufacturing, Eduardo Miramontes

Masters Theses

Wire Arc Additive Manufacturing (WAAM) has made great strides in recent years however, there remain numerous persistent challenges still hindering more widespread adoption. Defects in the parts produced degrade their mechanical performance. Inconsistency in the geometry of the weld beads or undesirable anomalies such as waviness, or humps can lead to loss of geometric accuracy and in extreme cases, when anomalies propagate to subsequent layers, build failure. Such defects can be mitigated by a controls framework, which would require a model that maps undesirable outcomes to information about the process that can be obtained in real time. This thesis explores …