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Laser Assisted Direct Writing Of Liquid Metal For Microprinting Applications, Olga Vargas Cruz
Laser Assisted Direct Writing Of Liquid Metal For Microprinting Applications, Olga Vargas Cruz
Theses and Dissertations
This paper presents a research study for potential printing of a Liquid Metal (LM) Eutectic Gallium Indium alloy (EGaIn) through the applications of the innovative additive manufacturing technology LIFT (Laser Induced Forward Transfer). LIFT is a precise printing technology that allows to create small, detailed printing. The liquid metal in study, EGaIn, has demonstrated great potential for microelectronics applications due to its minimum toxicity and high conductivity. Throughout this research different printing parameters are studied to comprehend the behavior of EGaIn printing with LIFT technique, these include laser energy, laser pulse, receiver material substrate, donor layer thickness, and …
Process-Structure-Property Relationships Of Nanofibers For Biomedical Applications, Dipasree Bhowmick
Process-Structure-Property Relationships Of Nanofibers For Biomedical Applications, Dipasree Bhowmick
Theses and Dissertations
This thesis explores the fabrication, characterization, and applications of nanofiber membranes utilizing Forcespinning® technology. Two distinct nanofiber systems were developed and evaluated, one focusing on pH-responsive Eudragit-baicalin loaded nanofibrous membranes for wound healing and the second one on thermo-responsive nanofiber-hydrogel (PNIPAAm) systems for biosensing applications, specifically dopamine detection. In the first project, nanofiber membranes loaded with Eudragit and baicalin demonstrated superior antibacterial properties against both gram-negative (E. coli) and gram-positive (B. meg) bacteria. Additionally, these membranes exhibited antioxidant properties and enhanced cell proliferation of 3TT cells, making them promising candidates for wound healing dressings. In the second project, a …
Human-Centric Smart Cities: A Digital Twin-Oriented Design Of Interactive Autonomous Vehicles, Oscar G. De Leon-Vazquez
Human-Centric Smart Cities: A Digital Twin-Oriented Design Of Interactive Autonomous Vehicles, Oscar G. De Leon-Vazquez
Theses and Dissertations
Autonomous vehicle (AV) technology is introduced as a solution to improve transportation safety by eliminating traffic accidents caused by human error, which is the leading cause of 90% of accidents. One key feature of AVs is sensing and perceiving their surrounding environment through processing observations collected from the environment. The perception system is essential for an AV to make informed decisions and safely navigate the environment. This study presents an image semantic segmentation algorithm developed in the area of computer vision to improve AV perception. The U-Net-based algorithm is trained and validated using a synthetically generated dataset in a simulation …
Developing Control System For Manufacturing Processes, Md Shahriar Forhad
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
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 …
Vibration-Based Machine Learning Models For Condition Monitoring Of Railroad Rolling Stock, Sergio M. Martinez
Vibration-Based Machine Learning Models For Condition Monitoring Of Railroad Rolling Stock, Sergio M. Martinez
Theses and Dissertations
One of the primary causes of rail rolling stock derailments is attributed to bearing and wheel axle failures. The health of train bearings is primarily monitored at target locations through wayside detection systems. This practice is susceptible to bearing failure and potential derailments at points in between these wayside systems. To remedy this, the University Transportation Center for Railway Safety (UTCRS) has developed a wireless onboard monitoring system that can continuously monitor the vibration response, which directly correlates to the health of bearings. This data is used to train regression-based machine learning algorithms and long-term prediction neural networks to predict …
Design And Implementation Of A Load Sensor In A Bearing Adapter Assembly For Freight Railcar Applications, Prince E. Mensah
Design And Implementation Of A Load Sensor In A Bearing Adapter Assembly For Freight Railcar Applications, Prince E. Mensah
Theses and Dissertations
The U.S. freight rail network, which covers approximately 140,000 route miles, is commonly regarded as the largest, safest, and most economical freight system in the world. It generates more than 167,000 jobs nationwide and has additional advantages over other modes of transportation, such as lower costs for logistics, public infrastructure upkeep, and decreases in traffic congestion, highway deaths, fuel consumption, and greenhouse gas emissions. Knowing the exact weight of cargo hauled by freight railcars can help avoid exceeding the loading thresholds set by the Association of American Railroads (AAR). Moreover, knowing the exact load applied to each bearing on the …
Aerodynamic Flow Control Using Micro Rotating Cylinders, Alejandro Daniel Carrizales
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 …
Image Segmentation With Human-In-The-Loop In Automated De-Caking Process For Powder Bed Additive Manufacturing, Vincent Opare Addo Asare-Manu
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
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 …
Wave Excited Mass-Spring-Damper System For A Self-Recharging Autonomous Underwater Vehicle, Mahmodul Hasan Maheen
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 …
Developing Executable Digital Models With Model-Based Systems Engineering – An Unmanned Aerial Vehicle Surveillance Scenario Example, Viviana Guadalupe Lopez
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
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 …
Using Actor-Critic Reinforcement Learning For Control Of A Quadrotor Dynamics, Edgar Adrian Torres
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
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 …
The Effects Of Carbon Coating On The Electrochemical Performance Of Metal-Oxide Short Fiber Anodes For Lithium-Ion Batteries, David A. Sanchez
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 …