Digital Commons Network^™

Investigation Of The Properties Of Nickel Titanium Shape Memory Alloys For Applications In Self-Healing Materials, Muhammad Istiaque Haider

Theses and Dissertations

This research explores the design and properties of self-healing metal-metal composites, with a specific focus on incorporating shape memory alloys (SMAs) and investigating the characteristics of post-constrained recovery residual stresses (PCRRS). The objective is to enhance the functionality, durability, and longevity of mechanical structures through the realization and optimization of self-healing materials.

The research delves into the experimental and analytical studies to gain a comprehensive understanding of the underlying mechanisms of PCRRS and SMA-reinforced self-healing metal matrix composites, specifically examining the interface strength between nickel-titanium (NiTi) wire and bismuth-tin (BiSn) solder. NiTi SMAs manifest a distinctive property, termed as PCRRS, …

Multi-Order Modeling Of Linear Magnetic Motor System, Ming-Jen Chen

Theses and Dissertations

Numerical simulations have been proven to be a powerful tool for predicting, testing, and validating the capabilities of new designs. However, given the high demand for simulating extremely complicated geometries and nonlinear physical phenomena, simulations can often be significantly time consuming. Consequently, the development of high-precision reduced-order models becomes indispensable to reduce computational time. In this study, we simplified and characterized an industrial motion system based on linear magnetic motor technology using accurate full 3-D numerical model. The system behavior was explored through various scenarios, including extreme conditions, to gain a deeper understanding of its thermal behavior during operation. The …

Embedded Ultrasonic Inspection Of Liquid Filled Pressure Vessels, Trevor Wenzel

Theses and Dissertations

Structural health monitoring and ultrasonic inspection techniques can be used to inspect a structure for degradation. There are several different approaches for doing this including the use of an embedded sensing system which uses elastic wave propagation through the structure. Previous work using this method has explored ultrasonic inspection of a simple, flat plate structure, however, structures often have more complex geometry, and the flat plate offers only a basic understanding of elastic wave propagation. Therefore, experimental approaches and results drive how these techniques can be used for ultrasonic inspection of complex vessels where challenges arise due to the potential …

Aerodynamic Flow Control Using Micro Rotating Cylinders, Alejandro Daniel Carrizales

Theses and Dissertations

This research investigates the aerodynamic and flow field characteristics of a NACA 0010 airfoil equipped with rotating cylinders near the leading edge, subjected to a flow with a freestream turbulence intensity of 4.3%. The airfoil was modified to integrate five micro-DC motors positioned at 14.5% of the chord length from the leading edge. The cylinders, with dimensions of 0.75 inches in diameter and 0.5 inches in width, exposed 3mm of their length to the incoming flow. A modified leading edge with eight sinusoidal protrusions (tubercles) was employed to compare the performance of the micro-rotating cylinder airfoil with an unmodified baseline …

Developing Control System For Manufacturing Processes, Md Shahriar Forhad

Theses and Dissertations

Process control has been a critical component in today's manufacturing industry. Industrialists nowadays want reliable control to assure precision manufacturing. Modern control systems must be more dynamic, so that any needed modifications may be made quickly to accomplish the desired product change. For innovative research and development, system customization is critical to ensure freedom for experimental works. In addition, full control of manufacturing systems is necessary to realize and implement Industry 4.0. Often, it is difficult to achieve such control due to limited access to proprietary equipment. To this end, this thesis focuses on developing a custom control platform for …

Two-Dimensional Nanomaterials And Nanocomposites For Sensing, Separation, And Energy Applications, Md Ashiqur Rahman

Theses and Dissertations

Two-dimension (2D) nanomaterials have gained popularity for the last few decades due to their excellent mechanical, electrical and thermal properties. These unique properties of 2D nanomaterials can be exploited in various applications specially in sensor, energy, and separation devices. In this study, the sensing and energy generation performance of PVDF/PAni fiber mat systems made by the forcespinning method with and without graphene coating. The graphene-coated nanocomposites show an average output voltage of 75 mV (peak-to-peak) which is 300% higher compared to bare fiber mats and an output current of 24 mA (peak-to-peak) by gentle finger pressing. Moreover, the graphene-coated PVDF/PAni …

Liquid Cooling System For A High Power, Medium Frequency, And Medium Voltage Isolated Power Converter, Hooman Taghavi

Theses and Dissertations

Controlling and transforming electrical power from one form into another is the Primary function of the power electronics systems that are employed today. These systems have a wide variety of applications and are utilized in things like industrial automation, electric cars, consumer electronics, and renewable energy systems, among other things. The functioning of power electronics systems results in the production of a substantial quantity of heat, despite the fact that these systems are very dependable and efficient. This heat must be dispersed to preserve system performance and avoid component damage. By ensuring that the working temperature of the components stays …

Automated Fiber Placement Through Thickness Defect Stacking Optimization, Noah Christopher Swingle

Theses and Dissertations

In its 2022 commercial market outlook, Boeing forecasted an 80% increase in the global fleet through 2041 compared to 2019 pre-pandemic levels. This sharp rise in demand will drive pressure onto airframe manufacturers to ramp up production and find more efficient ways to design and manufacture airplanes. Complicating this challenge is the industry’s recent transformation from traditional metal-based airframes towards hybrid composite-metal aircraft. While composites have been used in aviation for decades, aircraft manufacturers are still struggling to design and manufacture quality parts at a high rate. Automated Fiber Placement (AFP) is one of the main manufacturing techniques used to …

Image Segmentation With Human-In-The-Loop In Automated De-Caking Process For Powder Bed Additive Manufacturing, Vincent Opare Addo Asare-Manu

Theses and Dissertations

Additive manufacturing (AM) becomes a critical technology that increases the speed and flexibility of production and reduces the lead time for high-mix, low-volume manufacturing. One of the major bottlenecks in further increasing its productivity lies around its post-processing procedures. This work focuses on tackling a critical and inevitable step in powder-bed additive manufacturing processes, i.e., powder cleaning or de-caking. Pressing concerns can be raised with human involvement when performing this task manually. Therefore, a robot-driven automatic powder cleaning system could be an alternative to reducing time consumption and increasing safety for AM operators. However, since the color and surface texture …

Tio2 Coating Methods On Sb2o3 And Their Use As Anode Material In Lithium-Ion Batteries, Kithzia Czarina Gomez

Theses and Dissertations

The following thesis is concentrated on the development of TiO2Sb2O3 composite material through the hydrolysis of TiCl4 to be applied as anode material for lithium-ion batteries. Antimony (Sb) has been a material of interest due to its high capacity and good chemical properties. The TiO2 accommodated the harsh volume expansion that Sb encounters during the alloying process while still preserving the high capacity offered by Sb. Its electrochemical performance exhibited a stabilized capacity of 523 mAhg-1 after reaching 40 cycles with a capacity loss of 2.4% till reaching 100 cycles. High reversible capacity characteristics were present with an initial capacity …

Gpu-Enabled Genetic Algorithm Optimization And Path Planning Of Robotic Arm For Minimizing Energy Consumption, Yichuan Cao

Theses and Dissertations

The robotic arm represents a complicated mechanical system and advanced engineering principles in robotics, enabling precise and efficient manipulation and interaction with objects in a variety of applications, such as manufacturing, healthcare, space exploration, and other industries. In most cases, energy consumption of robotic tools has been given little consideration due to their perceived insignificance compared to the benefits they offer. However, the increasing capacity demands of factories and the expanding use of robotic arms necessitate careful evaluation and reduction of energy consumption. In this regard, given a task configuration, adjusting the arm's movement path emerges as one of the …

An Empirical Investigation Of The Behavior And Cognition Of Engineering Designers While Describing Domains Of Design Problems, John Kochenberger

Theses and Dissertations

This thesis presents a protocol study that examines the behavioral and cognitive patterns in human designers when they describe a problem domain of engineering interest through constructing concept maps. Understanding various design problem domains usually comes in design projects before the start of the formal design process and is crucial for discovering the pain points of given scenarios and identifying opportunities for creating value to improve them. Thus, this activity relies on the entrepreneurial aspects of engineering design that leads to identifying the right design problem to solve. While concept maps have been used to examine various research questions in …

Construction Of A Real-Time Forecast Model With Deep Learning Techniques For Coastal Engineering & Processes: Nested In Basin Scale Suite Of Models, Md Ahsan Habib

Theses and Dissertations

The study aims to develop a robust and adaptable real-time forecasting system for coastal and estuarine regions, considering the challenges of limited or unavailable forecast data. To address the challenge of data unavailability, this study proposes the application of a deep learning model (DLM). This research involves the development of a high-resolution numerical model nested within global models. Calibration and validation are performed by comparing the model with observed data. The study explores the effects of various parameters, such as vertical resolution, wind variability, and bottom roughness, on model performance. It finds that the 10-layer model improves vertical stratification and …

Development Of Atomistic Machine Learning Approaches For Thermal Properties Of Multi-Component Solids And Liquids, Alejandro David Rodriguez

Theses and Dissertations

Currently, heat transfer in many industries is the limiting factor for innovation, especially in the energy sector. For example, maximizing thermal conductivity of ceramic coatings in power plant devices improves the overall electrical to thermal energy ratio, whereas minimizing thermal conductivity is required for desirable heat-to-electricity conversion in thermoelectric devices. As such, rapid discovery of new materials with extreme thermal conductivity values is quintessential for the near-future deployment of current and developing energy applications.

The vibrational properties of crystalline materials are essential for their ability to conduct heat. Fundamentally, the restorative atomic forces of displaced atoms are sufficient to represent …

Additive Manufacturing Of Stretchable Strain Sensors: Fabrication, Optimization And Application, John Nady Shihat Bastawrous

Theses and Dissertations

In this project, a novel strain sensor design is fabricated employing different additive manufacturing techniques. The spring sensor's primary material is PLA-Like resin with a nanocomposite encapsulation layer as the functional material. The main principle of Straining the sensors results in a change in resistivity as the distances among the conductive carbon particles change according to the strain applied.

Sensor fabrication consists of two parts: spring manufacturing and development of nanocomposite encapsulation The nanocomposite matrix is developed through the dispersion of Graphene and Carbon nanotubes in Thermoplastic Polyurethane through sonication and magnetic hotplate stirring. While the spring itself is manufactured …

Computational Study On The Acoustic Footprint Of Stenosis In Larger Arteries, Ahmed Abdelnabi

Theses and Dissertations

We identify a new (acoustic) frequency-stenosis relations whose frequencies fall within the recommended auscultation threshold for stethoscopy (< 120 Hz) in this study. We demonstrate that these relations can be used to extend the application of phonoangiography (the measurement of the degree of stenosis from bruits) to stethoscopes that are broadly available. The First relationship is successfully identified using an analysis limited to the acoustic signature of the von Karman vortex street, which we automatically isolate using a metric based on an area-weighted average of the Q-criteria for the post-stenotic region. Specifically, we conduct LES-CFD simulations on simplified 2D internal flow geometries that represent blood vessels with varying degrees of stenosis. Then, using the Ffowcs Williams-Hawkings (FW-H) equation, we extract their emitted acoustic signals, which we subtract from a pure signal (stenosis-free) at the same heart rate. Next, we transform this differential signal to the frequency domain and meticulously classify its acoustic signatures according to six stenosis-invariant flow phases of a cardiac cycle. Using our Q-criterion-based metric, we then automatically restrict our acoustic analysis to the noises emitted by the von Karman vortex street (phase 4). Our analysis of its acoustic signature demonstrates a strong linear relationship between the degree of steno- sis and its dominant frequency, which differs significantly from the break frequency and heart rate (previously identified dominant frequencies). For the Second relationship, we develop a frequency-stenosis scaling law for particularly supravalvular aortic stenosis that falls within the preferred frequency range (30-120 Hz) for echocardiography. We expand to 3D patient specific geometry using Simulia’s Living Heart Human Model (LHHM), which has an anatomically accurate aorta geometry. This LHHM geometry is modified with stenoses ranging from 30 to 80 percent (moderate to severe). For physiologically consistent hemodynamic boundary conditions, we expand the study to employ the Windkessel model, which has been implemented on Fluent using UDF. We demonstrate that physiological boundary conditions reduce simulation time significantly compared to static boundary conditions. The FW-H model extracted the flow-generated acoustic signal of the stenotic geometries and analysed it at clinically relevant receiver locations. A preferred receiver location consistent with clinical practise is determined, and a correlation between the degree of stenosis and the prevalent acoustic frequency (within the frequency range of 70-120 Hz) is established. The obtained second scaling law is shown to be clinically reliable in assessing stenotic severity. Future research will investigate incorporating the vibroacoustic role of adjacent organs and tissue to expand the clinical applicability of our findings. Expansion of clinical and numerical datasets will be pursued in future research to enhance the reliability of our scaling law, possibly by leveraging much-needed ML-based acceleration schemes.

Methodology For Designing Assistive Robots For Activities Of Daily Living Assistance, Javier Dario Sanjuan De Caro

Theses and Dissertations

The growing prevalence of Upper or Lower Extremities Dysfunctions (ULED), often linked to central nervous disorders such as stroke, Spinal Cord Injury (SCI), and Multiple Sclerosis (MS), underscores the urgent need for innovative support solutions. Over 5.35 million Americans currently live with ULED, a situation that places a significant socioeconomic burden on families and society. Despite invaluable support from caregivers and family members, the need for more scalable, practical solutions persists.

Wheelchair-mounted assistive robots emerge as a promising alternative in this context. These devices, offering continuous and reliable assistance, significantly alleviate caregiver fatigue and enhance the independence and quality of …

Development Of A Modular Agricultural Robotic Sprayer, Paolo Rommel P. Sanchez

Theses and Dissertations

Precision Agriculture (PA) increases farm productivity, reduces pollution, and minimizes input costs. However, the wide adoption of existing PA technologies for complex field operations, such as spraying, is slow due to high acquisition costs, low adaptability, and slow operating speed. In this study, we designed, built, optimized, and tested a Modular Agrochemical Precision Sprayer (MAPS), a robotic sprayer with an intelligent machine vision system (MVS). Our work focused on identifying and spraying on the targeted plants with low cost, high speed, and high accuracy in a remote, dynamic, and rugged environment. We first researched and benchmarked combinations of one-stage convolutional …

Flexural Wave Manipulation By Non-Hermitian Planar Elastic Metasurface, Katerina Stojanoska

Theses and Dissertations

It has been demonstrated that metasurfaces with spatially asymmetric inner geometry exhibit unidirectional scattering effects, which can be used to control waves in a directional fashion. In this thesis, a planar Non-Hermitian elastic metasurface exhibiting unidirectional focusing of flexural waves is proposed. Asymmetrically loaded piezoelectric disks and metallic blocks comprise the unit cells. By using a negative capacitance shunting, a tunable material loss is embedded into the system. With suitable engineering of the induced loss profile, resonating building blocks are designed, which are capable of independently accessing unidirectional zero reflection. A planar metasurface is then created so that constructive interference …

A Screening Tool For The Implementation Of Electric And Thermal Energy Storage Systems At Commercial And Industrial Facilities, Mckenna P. Amerson

Theses and Dissertations

The integration of on-site renewable systems with energy storage devices is an important topic in improving energy management for commercial buildings and industrial facilities. Energy storage technologies have the ability to impact the end user’s power reliability while creating measurable energy and cost savings. However, the potential yet remains to increase the application of these systems. To determine the feasibility of renewables and energy storage in commercial and industrial applications, a pre-screening software tool is developed using data-driven algorithms to complete an energy, cost, and carbon savings analysis of storage implementation. A case study of a standalone retail building is …

An Electric Commerce Platform For Material Testing Laboratories, John Ferris Mitchener

Theses and Dissertations

The emergence of the Internet has allowed businesses to create new sales and marketing channels to provide value for their customers in the marketplace. Engineering manufacturers and suppliers have taken advantage of the internet to automate the customer service aspects of their businesses as well as to market their services in a cost-effective but widespread manner. This work aims to apply the practices and benefits of electronic commerce (e-commerce) to a material testing laboratory through the creation of a functioning website with e-commerce features. The effects of Search Engine Optimization, website accessibility issues, marketing considerations, security concerns, and common business …

Investigation Into Strain Sensing With Reduced Graphene Oxide, And Applications In Low-Cost Leak Detection And Health Monitoring Of Water Equipment, Armin Yazdi

Theses and Dissertations

Strain gauges are one of the most important transducers that can be used in many applications such as robotics, structural health monitoring, medicine etc. The expensive mass production, as well as lack of high sensitivity, high strain tolerance or high quality can be some of the challenges with the current strain gauges. The reduced graphene oxide possesses many of the excellent properties of graphene while being easy and inexpensive to be mass-produced. However, its electromechanical behavior under strain (especially large strains) has not been well studied. In this dissertation, strain sensing by reduced graphene oxide with Polydimethylsiloxane substrate is investigated …

Developing Executable Digital Models With Model-Based Systems Engineering – An Unmanned Aerial Vehicle Surveillance Scenario Example, Viviana Guadalupe Lopez

Theses and Dissertations

There is an increase in complexity in modern systems that causes inconsistencies in the iterative exchange loops of the system design process and in turn, demands greater quality of system organization and optimization techniques. A recent transition from document-centric systems engineering to Model-Based Systems Engineering (MBSE) is being documented in literature from various industries to address these issues. This study aims to investigate how MBSE can be used as a starting point in developing digital twins (DT). Specifically, the adoption of MBSE for realizing DT has been investigated, resulting in various literature reviews that indicate the most prevalent methodologies and …

The Synthesis And Characterization Of Metal Oxide Nanomaterial-Based Composites And Their Use As Antibacterial Agents, Jo A. Sanchez

Theses and Dissertations

The work presented in this thesis discusses the antibacterial properties of various metal oxides and metal oxide/polymer composite fibers. Polyvinylpyrrolidone (PVP) fibers embedded with Zinc Oxide nanoparticles (ZnO NPs) were prepared by centrifugal spinning from PVP aqueous solutions) and ZnO NPs. The ZnO NPs were synthesized and coated with different surfactants, cetyltrimethylammonium bromide (CTAB) and hexadecyltrimethylammonium bromide (HTAB). The effect of surfactant coating on the antibacterial activity of ZnO NPs and PVP/ZnO nanocomposite fibers against escherichia coli (e. coli) and bacillus megaterium (b. megaterium) bacteria was systematically investigated. The results showed that coating the ZnO NPs …

Wave Excited Mass-Spring-Damper System For A Self-Recharging Autonomous Underwater Vehicle, Mahmodul Hasan Maheen

Theses and Dissertations

Autonomous underwater vehicles' (AUVs) endurance is constrained by the lifetime of their batteries and the distance that tether wires can traverse. Solving the endurance problem of AUV using the enormous potential of ocean wave energy is the motivation behind this thesis. The objective of this research is to model a mass-spring-damper system to emulate the permanent magnet linear generator (PMLG) of a self-recharging AUV and identify its energy absorption capability through numerical simulation and experimental testing. The research activities started with modeling and fabricating a 1:5 scale model. The scaling was done by comparing the most common AUV size of …

The Effects Of Carbon Coating On The Electrochemical Performance Of Metal-Oxide Short Fiber Anodes For Lithium-Ion Batteries, David A. Sanchez

Theses and Dissertations

This thesis focuses on the process of oxidizing centrifugally spun precursor fibers and the subsequent process of carbon coating via chemical vapor deposition (CVD) for use as anode material in lithium-ion batteries (LIBs). Metal oxides have been studied as a potential replacement for graphite as they have been shown to have high theoretical capacities, good electronic conductivity, and can be synthesized using low-cost, scalable methods. However, metal oxides with high theoretical capacities also have low cycle life. To avoid this, metal oxides have been integrated with carbon to expand their life cycle. The work in this thesis shows the synthesis …

Using Actor-Critic Reinforcement Learning For Control Of A Quadrotor Dynamics, Edgar Adrian Torres

Theses and Dissertations

This paper presents a quadrotor controller using reinforcement learning to generate near-optimal control signals. Two actor-critic algorithms are trained to control quadrotor dynamics. The dynamics are further simplified using small angle approximation. The actor-critic algorithm’s control policy is derived from Bellman’s equation providing a sufficient condition to optimality. Additionally, a smoother converter is implemented into the trajectory providing more reliable results. This paper provides derivations to the quadrotor’s dynamics and explains the control using the actor-critic algorithm. The results and simulations are compared to solutions from a commercial, optimal control solver, called DIDO.

Near-Optimal Control Of A Quadcopter Using Reinforcement Learning, Alberto Velazquez-Estrada

Theses and Dissertations

This paper presents a novel control method for quadcopters that achieves near-optimal tracking control for input-affine nonlinear quadcopter dynamics. The method uses a reinforcement learning algorithm called Single Network Adaptive Critics (SNAC), which approximates a solution to the discrete-time Hamilton-Jacobi-Bellman (DT-HJB) equation using a single neural network trained offline. The control method involves two SNAC controllers, with the outer loop controlling the linear position and velocities (position control) and the inner loop controlling the angular position and velocities (attitude control). The resulting quadcopter controller provides optimal feedback control and tracks a trajectory for an infinite-horizon, and it is compared with …

Improving The Learning Efficiency Of Adaptive Optimal Control In Information-Limited Environments, Omar Ghassan Qasem

Theses and Dissertations

This work investigates the adaptive optimal control problems for continuous-time linear and nonlinear systems. A novel adaptive dynamic programming method, namely hybrid iteration (HI) is presented. Different from the existing adaptive dynamic programming methods, i.e., policy iteration (PI) and value iteration (VI), the HI does not require an initial admissible control policy compared to the PI. On the other hand, the HI converges to the optimal control policy in much less learning iterations and CPU time compared to the VI due to the ensured quadratic rate of convergence of the HI method, which is much faster than the sub-linear convergence …

Understanding The Effectiveness Between Modern Technologies And Traditional Training Methods Of E-Learning On An Individual’S Learning Curve, Content Retention, And Satisfaction, Andressa Camacho Ortiz

Theses and Dissertations

E-learning has become a widespread and valuable tool for skill development. After the COVID-19 pandemic, the necessity and adaptability of this method increased drastically. Hence, numerous studies focused on understanding the effectiveness of this method. The academic literature highlights the need to explore alternative solutions that can increase a learner’s content retention and satisfaction when learning remotely. Modern technologies can be a great solution for this need with the correct application and development. This thesis analyzes the effects of technology on content retention, satisfaction, and learning curve through the following technologies: online platform, virtual reality (VR), and hologram display. A …