Engineering Commons^™

Characterization Of Friction At The Tool/Material Interface In Friction Stir Welding, Bryan Gonzalo Ramos Gonzales

Theses and Dissertations

Friction Stir Welding (FSW) process development is very costly, and it is still experimental. A predictive model would optimize the weld by changing parameters and obtaining results that reflect the physical process. Friction is the primary adjustable parameter in FSW modeling. Currently, friction model selection is not physic-based. It is based on what is available and contributes to the best fit between the model and experimental data. The research objective is to characterize the interface tool/base material by studying the effect of tool friction coefficient and thermal properties. This is accomplished by changing welding parameters such as force, rpm, and …

Motives And Methodologies For Improving 3d Displays, Dylan Charles Barton

Theses and Dissertations

This work contains two key contributions to the development of 3D displays. First a successful exploratory human trial research study. By comparing multiple real displays in human trials, the factors of ease of use, time, and accuracy were able to be examined in a general setting, instead of isolated to only a specific type of 3D display. These human tests showed that 3D displays in general offer better ease of use and accuracy compared to 2D displays when showing 3D media. This differs from previous studies where only a single display was examined or theoretical papers discussing factors on paper. …

Cost Minimization For Charging Electric Bus Fleets, Daniel Mortensen, Jacob Gunther, Greg Droge, Justin Whitaker

Electrical and Computer Engineering Student Research

Recent attention for reduced carbon emissions has pushed transit authorities to adopt battery electric buses (BEBs). One challenge experienced by BEB users is extended charge times, which create logistical challenges and may force BEBs to charge when energy is more expensive. Furthermore, BEB charging leads to high power demands, which can significantly increase monthly power costs and may push the electrical infrastructure beyond its present capacity, requiring expensive upgrades. This work presents a novel method for minimizing the monthly cost of BEB charging while meeting bus route constraints. This method extends previous work by incorporating a more novel cost model, …

A Symbiotic Content Caching Approach In Next-Generation Information-Centric Networks Based On Game Theory, Aisha B Rahman

Electrical and Computer Engineering ETDs

The continuous growth of mobile data traffic with strict time requirements calls for the development of sustainable edge content caching solutions. This becomes more prominent in the setting of Information-Centric Networking (ICN) architectures, where different ICNs are leasing caching slices to the available content providers (CPs), who in turn offer their services to the users. In this thesis, we introduce a novel symbiotic content caching framework that provides the necessary economic benefits to the ICNs and the CPs to mutualistically collaborate among each other. The corresponding mutualistic interactions among the ICNs and CPs are studied under the prism of two …

Essays In Robust Optimization With Applications To Finance And Renewable Energy, Hao Jiang

Operations Research and Engineering Management Theses and Dissertations

Real-world optimization problems are often sensitive to uncertainties caused by estimation errors, forecasting inaccuracy, and imprecise data information. These uncertainties bring significant challenges to decision-making in many areas. Robust optimization (RO) is a tool for addressing the challenges of parameter uncertainty. In this dissertation, we focus on the studies of RO on two problems. (1) In the study of finance, we proposed a tractable RO model for a Mean-Variance portfolio selection problem. We consider Markowitz's Mean-Variance Optimization when stock returns are modeled using Sharpe's single-index framework, but the model coefficients Alpha and Beta, are not precisely known. This study assumes …

A Bio-Inspired Alternative Positioning, Navigation, And Timing Approach Based On A Potential Game-Theoretic Model, Md Sadman Siraj

Electrical and Computer Engineering ETDs

This thesis addresses the challenge of designing of alternative Positioning, Navigation, and Timing (PNT) solutions. Inspired by the evolution of biological ecosystems, we introduce a novel symbiotic PNT solution, based on the principles of Game Theory and the exploitation of Reconfigurable Intelligent Surfaces (RISs). A set of actors, consisting of anchor nodes and RISs with known coordinates, collaborator nodes having a rough estimate of their positions, and targets of unknown positions, are cooperating to accurately determine the targets’ positioning and timing. The key objective is to minimize the estimation error of each target and collaborator node, as well as of …

Design And Fabrication Of A Low Power 7.2 Terabit Transmitter For Exascale Computing, Scott Mcwilliams

Electrical Engineering Theses and Dissertations

Enhanced Coupled Strength (ECS) gratings fabricated into III-V based devices offer high reflected power per unit length and broad band reflectivity as compared to conventional 1st order gratings, desired qualities for short-haul high speed transmitters that can be implemented without the need for chip-level temperature control, contributing to the low power per transmitted bit. For commercial DBR lasers, the grating reflectivity results in an extremely narrow reflectivity spectrum, which is highly desired for most/many applications, but requires a power hungry thermo-electric cooler to maintain a fixed frequency. The proposed LEAM (laser electro-absorption modulator) requires a broad reflectivity spectrum, which, by …

Series Aperture Coupled Fed Phased Array Antenna, Guang Yang

Electrical Engineering Theses and Dissertations

Phased arrays are employed in a wide range of civil and Military contexts, including RADAR, cellular communications, and satellite communications. However, modern phased-array antennas require complex design and bulky structure at high costs, hindering their implementation in many applications. The critical aspect of a phased array design lies in power splitting with a proper phase to each radiating element. Conventional power splitters such as quarter-wavelength or Wilkinson power splitters suffer problems associated with complex array network and high power dissipation. Furthermore, popular phase shifters such as MEMS switch, ferrite-based or PIN diode have drawbacks of low power-handling capability, expensive packaging, …

On The Integration Of Hydrogen Into Integrated Energy Systems: Reliability Assessment And Optimal Operation And Planning, Tao Wu

Electrical Engineering Theses and Dissertations

Hydrogen, regarded as one of the cleanest energy carriers, is gaining momentum to support the realization of net-zero emissions integrated energy systems due to its versatile applications across various energy sectors. In the near-term, blending hydrogen into integrated energy systems offers opportunities to promote hydrogen integration considering the current high levelized cost of hydrogen. However, because of the different physical properties of hydrogen, the impact of hydrogen on the reliability and optimal operation of integrated energy systems should be investigated to maximize the share of hydrogen without degrading the functionality of integrated energy systems. In the long-term, the optimal planning …

Quantum And Classical Learning Algorithms For Grid Integration Of Energy Storage And Renewables: Operation, Modelling, And Planning, Bin Huang

Electrical Engineering Theses and Dissertations

With the pressing net-zero objectives, renewable energy sources (RESs) and energy storage systems (ESSs), which serve as the main force in providing low-carbon energy and flexibility, are being integrated into the power systems at an unprecedented rate. The rising penetration trend of RESs and ESSs brings both opportunities and challenges. In the short term, the inherent intermittency of RESs and high capital costs of ESSs introduce obstacles to revenue maximization for hybrid power plants and complicate the provision of privacy-ensured, high-fidelity network modeling. Long-term planning faces the hurdle of expanding ESS capacity in microgrids while maintaining power supply resilience with …

Early-Age Strength And Failure Characteristics Of 3d Printable Polymer Concrete: Numerical Modelling And Experimental Testing, Mohammad Amin Dehghani Najvani

Civil Engineering ETDs

The time-dependent rheological and early-age strength parameters of Polymer concrete (PC) were investigated. PC flow decreased, and the static yield stress and thixotropy increased as the specimen aged, while the dynamic yield stress remained unchanged. The study found that the Herschel-Bulkley model can accurately describe the PC’s rheological behavior over time. The change in cohesion strength and internal friction angle over time was observed using uniaxial unconfined compression and direct shear tests of fresh PC. A time-dependent MohrCoulomb failure criterion was established. Temperature analysis was used to determine the gel time and explain the evolution of the time-dependent early-age strength …

Modeling Of Asphalt Concrete For Cross-Anisotropic Visco-Elasticity And Heterogeneity, Zafrul Hakim Khan

Civil Engineering ETDs

Asphalt Concrete (AC) is a cross-anisotropic viscoelastic material. This study has developed a methodology to backcalculate the cross-anisotropic properties of the AC layer from the Falling Weight Deflectometer (FWD) sensor and pavement response data from embedded sensors inside a pavement section. This study has also developed a two-way coupled Multiscale Finite Element Model (MsFEM) with Phase Field Fracture (PFF) to study the microstructural heterogeneity and damage of the AC layer based on the actual field loadings. A Finite Difference Time Domain (FDTD) and Machine learning-based backcalculation algorithm were developed to determine the layer thickness and dielectric constant from air-coupled Ground …

Aerodynamic Dimpling For The Nose Cone Of A High-Power Competition Rocket, Graham Geoffrey Monroe

Mechanical Engineering ETDs

This thesis investigates nose cone dimpling for the reduction of the aerodynamic drag of a Level 3 High-Power amateur rocket. Two rocket launches were conducted. The first used a COTS nose cone with a smooth surface. A dimple distribution was created according to dimensions calculated by Sandia National Laboratories’ proprietary Right- Size Dimple Evaluator. A dimpled nose cone, designed with geometry matching the COTS component, was 3D printed. Axial acceleration and barometric pressure data, recorded by an onboard flight computer, were used to calculate and plot the drag coefficient as a function of the Reynolds number for the smooth and …

Main Effects Screening Study Of Fe/Kclo4 Thermal Battery Heat Pellet Resistive Activation, Bryan T. Steiner

Mechanical Engineering ETDs

Thermal battery iron-potassium perchlorate (Fe/KClO₄) heat pellets are often ignited by explosive igniters or heat paper. An alternative direct electrical ignition method via resistive heating is explored, which could improve thermal battery manufacturability and design flexibility. A main effects screening experiment was performed with the goal of confirming prior observed trends under more realistic test conditions and ranking the importance of design factors, to optimize future experiments and develop knowledge of the performance space. Relevant literature is examined to advance a theoretical understanding of resistive activation. Ignition sensitivity (go/no-go and time to ignition) and ignition energy are primary …

Control Of Fully-Actuated Aerial Manipulators And Omni-Directional Multirotors, Riley M. Mccarthy

Mechanical Engineering ETDs

This thesis details the system modeling, design, control, simulation, construction, and
testing of both a fully-actuated and omni-directional multirotor aerial system created
for the primary purpose of performing active tasks with their environment. This work
verifies the capabilities of both systems through empirical testing, and demonstrates
how through the use of new control methods and physical designs multirotors can
expand their purpose from passive inspection based tasks to active contact based
tasks. These systems take advantage of newly implemented control allocation features present in the PX4 flight control software, version 1.14. The use of which makes designing controllers for such …

Design, Fabrication And Characterization Of Zero Power Sensor/Harvester For Smart Grid Applications, Zeynel Guler

Mechanical Engineering ETDs

This study presents a flexible sensor/harvester device to be used in both electromagnetic sensing and energy harvesting applications for smart grids. When a current passes through a wire, the sensor detects the magnetic field created by that current. The sensor magnet interacts with the wire magnetic field resulting in a transfer of energy through the piezoelectric cantilever. Piezoelectric, conductive, magnetic, and magnetostrictive composite thin films were prepared to fabricate this device.

Initially, the magnet of the cantilever was optimized considering its shape, thickness, length, taper angle etc. via both simulations and experiments. Peak to peak voltage versus cantilever position graph …

Colloid Fabrication For Biomedical Engineering Applications Through Droplet Microfluidics, Lewis I. Larsen

Biomedical Engineering ETDs

The goal of this work was to leverage soft colloid fabrication through droplet microfluidics to improve the biomedical fields of radiotracer microspheres for selective internal radiation therapy (SIRT) and 3D hydrogel tissue constructs for cell culture with future potential as a platform to study liver diseases and drug response. The importance of positron emission tomography (PET) imaging microspheres infused with positron-emitting radioisotopes such as Ga-68, Cu-64, and F-18 is that they accurately map tumor-to-liver uptake (TLR) ratio and lung shunting factor of hepatocellular carcinoma. These pretreatment radiotracers model the intravascular accumulation behavior of radioactive therapeutic Y-90 SIRT microspheres. Qualifying patients, …

Physical Properties Of Copper Niobium Nanolamellar Composites Fabricated By Accumulative Roll Bonding, Jared Justice

Nuclear Engineering ETDs

Nanolamellar composites with high interface density have increased strength due to interfaces serving as barriers to dislocation movement and high radiation damage resistance. However, these interfaces also serve as barriers to electron motion, reducing the electrical resistivity and thermal conductivity. This work seeks to understand the inherent tradeoff between strength and physical properties of nanolamellar composites produced by accumulative roll bonding with layer thickness ranging from 25 nm to 193 nm. The electrical resistivity was investigated over temperatures ranging from 2 K to 300 K. The effect of longitudinal rolling and cross rolling was also investigated. Electrical resistivity results were …

Volumetric Imaging Using The Pupil-Matched Remote Focusing Technique In Light-Sheet Microscopy, Sayed Hassan Dibaji Foroushani

Optical Science and Engineering ETDs

ABSTRACT

The dissertation explores innovative techniques in light sheet microscopy, a pivotal tool in biomedical imaging, to enhance its speed, resolution, and efficiency in capturing dynamic biological processes. Light sheet microscopy allows for quick 3D imaging of biological specimens ranging from cells to organs with high spatiotemporal resolution, large field-of-view, and minimal damage, making it vital for in vivo imaging.

The first project introduces a novel optical concept designed to optimize Axially Swept Light Sheet Microscopy (ASLM). This technique is crucial for imaging specimens ranging from live cells to chemically cleared organs due to its versatility across different immersion media. …

Screw Dislocations In A Holed Wedge, Gregory T. Whiteside

Mechanical Engineering ETDs

A numerical code has been designed and implemented to find the stress at any material point in a holed-wedge material due to any number of crystal or real screw dislocations in the wedge. The code implements the image dislocation method together with the collocation point method to find stresses at any material point. We demonstrate that the combined analytical-numerical method (analytical with the image dislocations and numerical with the collocation-point method) is valid in that it produces stress fields giving rise to zero traction on free surfaces as well at an arbitrary number of collocation points on void surfaces. Additionally, …

Location Aware Task Offloading Framework For Edge Computing Empowered By Reconfigurable Intelligent Surfaces, Md Sahabul Hossain

Electrical and Computer Engineering ETDs

In this thesis, an energy efficient task offloading mechanism in a multi-access edge computing (MEC) environment is introduced, based on the principles of Contract Theory. The technology of Reconfigurable Intelligent Surfaces (RIS) is adopted and serves as the enabler for the energy efficient task offloading, from the perspective of location-awareness and improved communication environment. Initially a novel positioning, navigation, and timing solution is designed, based on the RIS technology and an artificial intelligent method that selects a set of RISs to perform the multilateration technique and determine the Internet of Things (IoT) nodes’ positions in an efficient and accurate manner …

Short-Term Forecasting Airport Passenger Flow During Periods Of Volatility: Comparative Investigation Of Time Series Vs. Neural Network Models, David H. Hopfe, Kiljae Lee, Chunyan Yu

Publications

Recurrent Neural Networks (RNNs), known for handling complex data tasks like language translation and speech recognition, are seldom employed in airport management practice for daily and weekly passenger flow forecasting tasks. In this paper, we evaluate the effectiveness and adaptability of various neural network models (RNN, LSTM, GRU, Deep LSTM, Bidirectional LSTM, multivariate RNN, and multivariate LSTM) against standard time series models (ARIMA, SARIMA, and SARIMAX) for a short-term forecasting airport security checkpoint passenger flows at five major U.S. airports during the pandemic.

At Atlanta's Hartsfield-Jackson Airport (ATL), the RNN notably surpasses SARIMA's forecasting accuracy by 34% (DM= 3.44, p …

Socially Engaged Engineering: A Framework For K-8 Education, Christine M. Cunningham, Gregory J. Kelly, Ashwin Mohan

Journal of Pre-College Engineering Education Research (J-PEER)

Socially engaged engineering provides for student learning of the design, analysis, and practices of engineering as well as the ways that engineering is situated in sociocultural contexts. This paper provides a conceptual framework regarding socially engaged engineering for K-8 educators, researchers, and curriculum designers. The framework identifies ways to support youth learning of engineering and considerations of technical, social, environmental, and ethical dimensions of engineering. As engineering enters K-8 educational settings, it is important to introduce the discipline in equity-oriented ways. We draw from the field of engineering for social justice to build this framework for examining engineering at the …

A Preliminary Study On Floating Flexible Otec Cold Water Pipe, Nai Kuang Liang, Hai Kuan Peng

Journal of Marine Science and Technology–Taiwan

Ocean Thermal Energy Conversion (OTEC) requires a large amount of cold seawater. The traditional rigid pipe, semi-rigidly fixed onto the ship bottom is not easy to install and disassemble, so the Floating Flexible Cold Water Pipe (FFCWP) flexibly connected to the ship is proposed. A small FFCWP was designed, fabricated, and successfully installed and recovered in the sea. The flexible pipe adopts commercially available fire ventilation snake pipe. The pipe wall material strength must be improved in the future. Assuming that the drag coefficient Cd value is 1.5, a numerical calculation is employed to simulate the FFCWP attitude from the …

Machine Learning With Multi-Source Data To Predict And Explain Marine Pilot Occupational Accidents, Gokhan Camliyurt, Youngsoo Park, Daewon Kim, Won Sik Kang, Sangwon Park

Journal of Marine Science and Technology–Taiwan

Marine pilot occupational accidents during transfer to/from ships are the primary concern of the International Marine Pilots’ Association (IMPA) and industry professionals. There are multiple transfer methods for marine pilots, with the most common being the pilot boat. To reach the mother ship bridge, the following stages must be safely completed: car transfer, walking on the pier, pier to pilot boat, pilot transfer by boat, cutter to pilot ladder, mother ship freeboard climbing, and ship deck to the bridge. Each stage has its own risk. Previous accident records and expert opinions are commonly used to conduct a risk analysis and …

Evaluation Of Operational Performance Of Wusongkou Cruise Port Through Network Data Envelopment Analysis, Qian-Feng Wang, Guo-Ya Gan, Xin-Liang Ye, Hsuan-Shih Lee

Journal of Marine Science and Technology–Taiwan

As major hubs for cruise berthing and passenger transfers, cruise ports in China were developing rapidly in the years before the COVID-19 pandemic because of an ever-growing regional market. Wusongkou Cruise Port is the most important port for cruise ships in China, and this study evaluated the operational performance of this port during 2011–2020. To this end, two-stage network data envelopment analysis was conducted to evaluate the port’s operation performance; subsequently, the change trajectory of the port’s operational efficiency during 2011–2020 was determined, and the potential reasons for the identified changes are discussed. Finally, suggestions for improving the operational performance …

Enhancing Wettability Prediction In The Presence Of Organics For Hydrogen Geo-Storage Through Data-Driven Machine Learning Modeling Of Rock/H2/Brine Systems, Zeeshan Tariq, Muhammad Ali, Nurudeen Yekeen, Auby Baban, Bicheng Yan, Shuyu Sun, Hussein Hoteit

Research outputs 2022 to 2026

The success of geological H2 storage relies significantly on rock–H2–brine interactions and wettability. Experimentally assessing the H2 wettability of storage/caprocks as a function of thermos-physical conditions is arduous because of high H2 reactivity and embrittlement damages. Data-driven machine learning (ML) modeling predictions of rock–H2–brine wettability are less strenuous and more precise. They can be conducted at geo-storage conditions that are impossible or hazardous to attain in the laboratory. Thus, ML models were utilized in this research to accurately model the wettability behavior of a ternary system consisting of H2, rock minerals (quartz and mica), and brine at different operating geological …

Optimal Control Of Ion Exchange Process For Chromate Removal And Protein A Chromatography For Antibody Extraction, Fadi Ghanem

Theses and Dissertations

Ion exchange resins are widely used in the extraction of hazardous chemicals as well as the recovery of precious molecules. Therefore, an early breakthrough from the resin system can lead to toxic compounds affecting the drinking water quality or inefficient use of costly resins. Hence, accurate modeling of the ion exchange process and control strategy can enable decisions that assist in avoiding leakage when facing fluctuations in the inlet contaminant concentrations. In this work, the ion exchange process is modeled via the method of moments where the system uncertainties are captured via stochastic modeling using Ito processes. The flow rate …

Air-Jet Bioprinting Of Stem Cell-Encapsulated Alginate Micro-Droplets For Organoid Biomanufacturing, Mirabella B. Stump

Electronic Theses and Dissertations

Biomanufactured 3D-organoids show promise for modeling and treating various conditions, particularly insulin-dependent diabetes mellitus (type-1 diabetes). Pancreatic islet organoids serve as sustainable sources of insulin-producing β-cells, potentially restoring insulin regulation in patients and providing a long-term solution for diabetes. Hydrogel droplet printing is an emerging technique in regenerative medicine due to its advantageous tunability and biocompatibility; however, challenges of consistency, quality control, and scalability persist. To address these issues, we developed a novel air-jetting based droplet bioprinting system for the generation of monodispersed alginate micro-droplets. The objective of this project was to incorporate human induced pluripotent stem cells (hiPSCs) into …

Large - Scale Manufacturing Of Fluorescent Perfluorocarbon Nanoemulsions For Oxygen Delivery, Anneliese Troidle

Electronic Theses and Dissertations

Over 100,000 Americans are currently waiting for a life – saving organ transplant, yet 17 patients die daily waiting for a transplant they will never receive [1]. Preservation of organs is an area that has seen innovation throughout the years and can improve rates of transplantation, yet vascularized composite allotransplantation preservation has not followed suit [2]. Current standard of care is use of electrolyte solutions such as Histidine – Tryptophan – Ketoglutarate (HTK) or University of Wisconsin (UW) Solution, yet these perfusates lack an oxygen carrying component [3]. Hemoglobin – based oxygen carriers (HBOCs) …