Engineering Commons^™

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …

5g New Radio Access And Core Network Slicing For Next-Generation Network Services And Management, Abdullah Ridwan Hossain

Dissertations

In recent years, fifth-generation New Radio (5G NR) has attracted much attention owing to its potential in enhancing mobile access networks and enabling better support for heterogeneous services and applications. Network slicing has garnered substantial focus as it promises to offer a higher degree of isolation between subscribers with diverse quality-of-service requirements. Integrating 5G NR technologies, specifically the mmWave waveform and numerology schemes, with network slicing can unlock unparalleled performance so crucial to meeting the demands of high throughput and sub-millisecond latency constraints.

While conceding that optimizing next-generation access network performance is extremely important, it needs to be acknowledged that …

Assessing The Feasibility And Mechanism Of Destructive Removal Of Per- And Polyfluoroalkyl Substances (Pfas) From Water, Kaushik Vinaykumar Londhe

Dissertations

One of the most pertinent challenges faced by the drinking water community is the widespread contamination of per- and polyfluoroalkyl substances (PFAS). These anthropogenic chemicals have been ubiquitously used in everyday products such as carpets, stain repellents, dyes, shampoos, non-stick cookware as well as in aqueous firefighting foams. PFAS are linked with adverse health effects in humans such as thyroid disease, obesity, immunological and reproductive disorders and linked to cancer in adults and low birth weight and developmental defects in infants.

Conventional water treatment technologies have proven to be largely ineffective in PFAS remediation, due to their extreme stability and …

Gen-Acceleration: Pioneering Work For Hardware Accelerator Generation Using Large Language Models, Durga Lakshmi Venkata Deepak Vungarala

Theses

Optimizing computational power is critical in the age of data-intensive applications and Artificial Intelligence (AI)/Machine Learning (ML). While facing challenging bottlenecks, conventional Von-Neumann architecture with implementing such huge tasks looks seemingly impossible. Hardware Accelerators are critical in efficiently deploying these technologies and have been vastly explored in edge devices. This study explores a state-of-the-art hardware accelerator; Gemmini is studied; we leveraged the open-sourced tool. Furthermore, we developed a Hardware Accelerator in the study we compared with the Non-Von-Neumann architecture. Gemmini is renowned for efficient matrix multiplication, but configuring it for specific tasks requires manual effort and expertise. We propose implementing …

The Effects Of Blue Light From Digital Displays On Visual Fatigue, Victor Taboadela

Theses

With the ever-increasing viewing time of digital displays, the potential effects of blue light emitted from these displays on eye health and eye fatigue are a real concern. This study presents a literature review of six laboratory studies conducted between 2014 and 2022 on the effect of using filters to attenuate the harmful effects of blue light. The review delves into smartphone and computer screen effects, recent literature reviews on blue light, and potential hazards associated with short-wavelength light. Although the majority of the studies recommended blue light filters, only three of the six laboratory studies (Shi et al. 2021, …

Borophene And Graphene For Non-Enzymatic Biosensor- Ab-Initio Study, Omar A. Ismail

Theses and Dissertations

Non-enzymatic glucose sensing holds promise to overcome limitations associated with glucose oxidase, such as oxygen dependence and short shelf life. This study explores the potential sensing capabilities of borophene and graphene through direct interaction with various compounds, including β-glucose, uric acid, ascorbic acid, fructose, and acetaminophen. Using Density Functional Theory (DFT), we calculated binding energies and the respective Density of States (DOS) for these adsorbates on both graphene and borophene surfaces. Preliminary results suggest that borophene might exhibit nearly twice the affinity for β-glucose compared to graphene. Moreover, the calculated Density of States reveals distinct distortions in the electronic states …

Rans-Dns Simulations For Uncertainty Quantification In Dns Data Of Turbulent Mixing Layer, Mohamed Abuhegazy

Mechanical Engineering ETDs

Mixing layer flow is one of the canonical free shear flows in fluid dynamics. Such a flow is formed when two fluid streams move along one another with different velocities. Investigation of this flow development has been an active topic of research for many decades not only due to a wide range of environmental and technological applications where this flow may be observed, but also because of large discrepancies in the results obtained experimentally and numerically regardless this flow simple geometry. In this dissertation, the quality and uncertainty of extracted turbulent statistics of mixing layer flow are analyzed by applying …

Uncertainty Quantification Of Live Load Effect In Buried Rc Box Culverts, Mohd Firoj

Dissertations and Theses

Although buried and mostly invisible to the traveling public, bridge-sized culverts (i.e., culverts with span around or longer than 20 ft) account for a large proportion of state-managed bridges. As per Oregon Department of Transportation inventory, there are approximately 35,000 culverts in the state highway system. Among them, 10,862 are in poor conditions and need to be analyzed for load rating purposes. The prediction and understanding of live load effects in culverts are crucial to the design, evaluation, and life-cycle maintenance of culverts. These live load effects include maximum bending moments and shear forces at different critical cross sections.

This …

Estimating And Detecting Slow-Wave Events In Eeg Signals, Zhenghao Xiong

McKelvey School of Engineering Theses & Dissertations

Slow wave activity (SWA) is an electroencephalogram (EEG) pattern commonly occurring during anesthesia and deep sleep, and is hence a candidate biomarker to quantify such states and understand their connection to various phenotypes. SWA consists of individual slow waves (ISW), high-amplitude deflections lasting for approximately 0.5 to 1 second, and occurring quasi-periodically. This latter fact poses a challenge for conventional power spectral density EEG analysis methods that perform best when there is persistency of oscillatory activity. In this work, we pursue a time-domain detection framework for identifying and quantifying ISWs as a metric for SWA. Our method works, in essence, …

A Systems Approach To Process Design And Sustainability - Synergy Via Pollution Prevention, Control, And Source Reduction, Emmanuel Apau Aboagye

Theses and Dissertations

Historically, process design prioritized efficiency and profitability, often overlooking environmental and societal implications. However, given the global challenges like climate change and resource scarcity, there is a growing emphasis on embedding sustainability into process design. Adopting a systems-oriented approach provides a comprehensive view, spanning from raw material acquisition to end-of-life product management. Such an approach not only identifies potential sustainability challenges but ensures that solutions foster both environmental responsibility and economic viability. In this study, a comprehensive framework for designing industrial systems is introduced, aiming to encompass the entire lifecycle impacts of chemical processes. The research initially delves into two …

Towards Patient Specific Mitral Valve Modelling Via Dynamic 3d Transesophageal Echocardiography, Patrick Carnahan

Electronic Thesis and Dissertation Repository

Mitral valve disease is a common pathologic problem occurring increasingly in an aging population, and many patients suffering from mitral valve disease require surgical intervention. Planning an interventional approach from diagnostic imaging alone remains a significant clinical challenge. Transesophageal echocardiography (TEE) is the primary imaging modality used diagnostically, it has limitations in image quality and field-of-view. Recently, developments have been made towards modelling patient-specific deformable mitral valves from TEE imaging, however, a major barrier to producing accurate valve models is the need to derive the leaflet geometry through segmentation of diagnostic TEE imaging. This work explores the development of volume …

Robust Visual Observer And Controller Design For System Modeled On Se(3) With Camera Measurements, Tong Zhang

Electronic Theses and Dissertations

This dissertation presents a controlling method that utilizes visual observation to address the challenge of driving an autonomous vehicle with a kinematic model on SE(3), by using the data obtained from the onboard cameras. This controlling framework is applicable when direct retrieval of the vehicle's attitude information is not possible or when precision control of the vehicle is necessary. However, addressing several challenges to attain closed-loop stability for the observer-based control for autonomous vehicles on SE(3) is essential. 1. The analysis is further complicated by the presence of multiple equilibria in the error dynamics associated with the suggested method. 2. …

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 …

Optimal Method To Obtain Soil Strength Properties In Sands For Laterally Loaded Pile Analysis In Lpile, Troy Roger Washburn

Theses and Dissertations

One common software program developed for analyzing single laterally loaded piles is called LPILE. Soil properties are required as input into LPILE. For sands, the soil properties required are effective soil unit weight, γ’; subgrade modulus, k; and the internal friction angle, ϕ’. There are two commonly used methods to obtain ϕ’ and subsequently k: the API method and Bolton method. Fourteen different pile test sites were used in the analysis of the API and Bolton methods to obtain soil strength properties in sands for laterally loaded single pile tests. Between the fourteen pile test sites, a total of 26 …

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, …

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 …

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. …

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 …

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, …

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, …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Investigation Of Thermofluid Processes In A Pcm Based Thermal Storage Module, Luca M. Crnjac

Electronic Thesis and Dissertation Repository

Latent heat thermal energy storage systems can capture and store solar thermal energy, enhancing the reliability of solar energy by facilitating a continuous and consistent energy supply. However, phase change materials used in these systems suffer from low thermal conductivities making it difficult to achieve suitable charging and discharging rates. The present research investigated this issue using computational and experimental approaches to improve the design of a thermal storage module through heat transfer enhancement. Various heat transfer enhancements including a finned honeycomb structure, and metal wool were incorporated into a thermal storage module to analyze their effect on charging and …