Engineering Commons^™

Interlaboratory Study Of The Operational Stability Of Automated Sorption Balances, Samuel L. Zelinka, Samuel V. Glass, Eleanor Q. D. Lazarcik, Emil E. Thybring, Michael Altgen, Lauri Rautkari, Simon Curling, Jinzhen Cao, Yujiao Wang, Tina Kunniger, Gustav Nystrom, Christopher Hubert Dreimol, Ingo Burgert, Mohd Khairun Anwar Uyup, Tumirah Khadiran, Mark G. Roper, Darren P. Broom, Matthew Schwarzkopf, Arief Yudhanto, Mohammad Subah, Gilles Lubineau, Maria Fredriksson, Marcin Strojecki, Wieslaw Olek, Jerzy Majka, Nanna Bjerregaard Pedersen, Daniel J. Burnett, Armando R. Garcia, Els Verdonck, Frieder Dreisbach, Louis Waguespack, Jennifer Schott, Luis G. Esteban, Alberto Garcia-Iruela, Thibaut Colinart, Romain Remond, Brahim Mazian, Patrick Perre, Lukas Emmerich, Ling Li

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Automated sorption balances are widely used for characterizing the interaction of water vapor with hygroscopic materials. These instruments provide an efficient way to collect sorption isotherm data and kinetic data. A typical method for defining equilibrium after a step change in relative humidity (RH) is using a particular threshold value for the rate of change in mass with time. Recent studies indicate that commonly used threshold values yield substantial errors and that further measurements are needed at extended hold times as a basis to assess the accuracy of abbreviated equilibration criteria. However, the mass measurement accuracy at extended times depends …

Iterative Correction Of Robotic Grinding Using Spatial Feedback For Precision Applications, Philip A. Olubodun, Joseph D. Fischer, Douglas A. Bristow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Since the advent of robots, many tasks that were originally performed by humans have now been tasked to industrial robots. From a manufacturing standpoint, robots have primarily been used in pick-and-place or other non-machining operations that require high repeatability. However, with the increasing availability of CAD/CAM software and the development of high-precision metrology, comes the opportunity to integrate robots into a wider variety of manufacturing processes through the use of feedback control. One such machining operation that is being explored is precision grinding of metal parts. Most other work in this area has focused on force regulation to improve grind …

A Feedforward Kinematic Error Controller With An Angular Positioning Deviations Model For Backlash Compensation Of Industrial Robots, Mitchell R. Woodside, Tian Hao Cui, John Emelko, Soichi Ibaraki, Robert G. Landers, Douglas A. Bristow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The accuracy of industrial robots, typically on the order of several millimeters, has inhibited their adoption in advanced aerospace manufacturing applications, such as robotic machining. For this reason, extensive investigations have been conducted to develop solutions to improve their accuracy. These solutions can be categorized into offline and online compensation strategies, both of which have advantages and limitations. Offline compensation has been shown to improve the accuracy of industrial robots by two to three orders of magnitude; however, the sensitivity of these solutions to environmental changes and external disturbances can degrade their performance. In contrast, online compensation, which utilizes real-time …

Wind Shear Induced Tornados With Full Thermodynamic Effects, Kakkattukuzhy M. Isaac

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Wind shear-induced Tornado behavior under full thermodynamic formulation using the ideal gas equation is investigated. The computational fluid dynamics model that includes the energy equation is used to obtain solutions of a natural-scale tornado under pressure and temperature boundary conditions that account for their variations vs. altitude in the atmosphere. The present results show significant differences from previous isothermal simulations and those using the Boussinesq model for buoyancy under small temperature differences. Results show that the downdraft observed in tornados originating from supercells, often accompanied by rain and hail can be captured using the present model that simulates the genesis, …

A Review On Photoacoustic Spectroscopy Techniques For Gas Sensing, Dakshith Ruvin Wijesinghe, Md Abu Zobair, Mina Esmaeelpour

Electrical and Computer Engineering Faculty Research & Creative Works

The rapid growth of industry and the global drive for modernization have led to an increase in gas emissions, which present significant environmental and health risks. As a result, there is a growing need for precise and sensitive gas-monitoring technologies. This review delves into the progress made regarding photoacoustic gas sensors, with a specific focus on the vital components of acoustic cells and acoustic detectors. This review highlights photoacoustic spectroscopy (PAS) as an optical detection technique, lauding its high sensitivity, selectivity, and capability to detect a wide range of gaseous species. The principles of photoacoustic gas sensors are outlined, emphasizing …

Fly Like A Naval Aviator: Effect Of Procedural Angle-Of-Attack Training On Pilot Comprehension And Decision-Making In General Aviation, Tara Samuels

Doctoral Dissertations and Master's Theses

To make life-saving equipment more accessible to general aviation (GA) aircraft owners and operators, the FAA streamlined installation of angle of attack (AOA) systems in GA fleets. Yet studies suggest GA pilots are ill-equipped to use these systems without training. Pilot performance suffers when an AOA is added to the flight deck because pilots’ knowledge with these systems is merely declarative (know-what) and not sufficiently procedural (know-how). Furthermore, GA pilots struggle to integrate the indicator into their existing (and well-rehearsed) mental models.

The study used a two-way mixed-design analysis of variance with a within-between- subjects approach to examine the effect …

Assessing The Influences Of Electronic Flight Bags On General Aviation Single Pilots’ Situation Awareness In Various Conditions, Dongguang Yu

Doctoral Dissertations and Master's Theses

The widespread adoption of Electronic Flight Bags (EFBs) among general aviation pilots prompts safety concerns regarding transitioning from traditional, heavily loaded paper-based flight bags. However, studies evaluating the impact of EFBs on general aviation pilots’ situation awareness are limited. This study aimed to determine whether EFBs enhanced or hindered general aviation pilots’ situation awareness.

The research compared EFBs with traditional paper-based flight bags to investigate pilots’ situation awareness in a single-pilot flight deck under visual flight rules, normal and emergency flight scenarios, and different mounting positions. A sample of 38 participants was recruited, including flight students, flight instructors, and retired …

In-Situ Characterization And Machine Learning Applications For Composite Processing, Pragathi Agraharam Chan

Doctoral Dissertations and Master's Theses

Numerous aircraft and spacecrafts utilize carbon fiber-reinforced polymer structures to significantly enhance their operational efficiency and overall performance. Autoclave composite processing offers a solution for the intricate design of complex structures. However, the rapid temperature and strain fluctuations experienced during the processing gives rise to a multitude of defects and residual stresses in the composite. In this study, we have devised an in-situ methodology that leverages Digital Image Correlation (DIC) and Machine Learning Applications to effectively observe and track defect deformations occurring throughout the process. This process presents a dataset derived from the curing process of 40 carbon fiber-reinforced polymer …

Model Predictive Control For Autonomous Landing In Complex Scenarios, Konstantinos Sotirakos

Doctoral Dissertations and Master's Theses

The autonomous flight industry is ever-expanding and continuing to push the boundaries of what is possible within the limitations of technology. Multiple companies are exploring the use of autonomous flight for intra-city travel with air taxi services and package delivery vehicles. Other companies are exploring the use of autonomous vehicles for military applications, such as Sikorsky with a next generation Black Hawk helicopter to ensure the safety of soldiers in high threat or altogether dangerous scenarios. In this thesis model predictive control (MPC) algorithms are developed to enable a quadcopter to operate and land autonomously in challenging environments. Specifically, MPC …

Assessing The Impact Of Femur Morphological Variations On Pediatric Hip Joint Biomechanics Using Statistical Shape Modeling, Tamara Chambers

Doctoral Dissertations and Master's Theses

This dissertation aimed to (1) quantify morphological variations in the pediatric hip joint and (2) evaluate the sensitivity of an infant musculoskeletal model (MSM) to these variations, considering hip joint center estimation errors. A shape statistical model (SSM) of decedent infant femurs from the Ortolani collection was created using ShapeWorks, capturing key morphological features, such as variations in the femoral neck-shaft and anteversion angles. Seven synthetic femurs were generated from the SSM to create SSM-informed MSMs, which were systematically evaluated through kinematics and kinetics analyses in OpenSim. Incorporating the SSM led to slight changes in the pediatric MSMs’ kinematics but …

Dynamic Estimation Of Large-Scale Flow Events In Open Cavity Flows, Alexandre Mota

Doctoral Dissertations and Master's Theses

Flow over an open cavity has a dynamically complex flowfield, generating pressure fluctuations that can amplify shear stress and cause structural damage to the stores within it and the aircraft as a whole. These pressure loads are linked to large-scale resonant shear layer phenomena. Consequently, it is crucial to establish this link by characterizing the large-scale flow events conditional upon pressure measurements to improve the prediction and control of the detrimental pressure fluctuations. In this study, a link between the pressure measurements (to control) and large-scale shear layer events (to actuate) will be established using a combination of two data-driven …

Optical Investigation Of A Low-Pressure Plasma In A Superconducting Radio-Frequency Cavity, Zachary A. Caudell

Electrical & Computer Engineering Theses & Dissertations

The state-of-the-art cryomodules for particle accelerators use superconducting radio-frequency (SRF) cavities. It is known that accumulation of hydrocarbon impurities reduces the cavity surface work function, decreasing cryomodule performance metrics such as field emission, thermal stability, and accelerating gradients. An in-situ method of plasma processing has recently been developed to clean the cavities and restore cryomodule performance [1]. This study is to understand the properties of the low-pressure plasmas generated in a C100 SRF cavity and ultimately to improve the performance of plasma surface cleaning using optical emission spectroscopy. Using a 500 mm focal length Czerny-Turner monochromator coupled with a photomultiplier …

An Exploratory Case Study Of Complex System Governance Diagnostics, Satya N. Moorthy

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this study was to conduct an initial diagnosis of the state of Complex System Governance (CSG) using a case study research design. The field of Complex System Governance (CSG), rooted in systems theory and management cybernetics, is the “design, execution, and evolution of the metasystem functions necessary to provide control, communication, coordination, and integration of a complex system.” This research explored literature in the fields of CSG, Organizational Diagnostics, and Performance Measurement as contributing literature streams for CSG Diagnostics and identified a gaps in the literature. This research addresses those gaps by exploring what results from applying …

Real-Time Navigation System For Breast Cancer Surgery With Pre- And Intra-Operative Imaging Using Neural Networks, Motaz Alqaoud

Biomedical Engineering Theses & Dissertations

Breast cancer is one of the most frequently diagnosed malignancies in women worldwide, necessitating precise diagnosis and treatment. Breast-conserving surgery (BCS) is the primary treatment for nonpalpable cases, yet current approaches often lack accuracy due to the absence of real-time 3D imaging during surgery. This limitation impairs surgeons’ ability to visualize tumor locations, compromising outcomes and potentially leading to repeat surgeries with higher risks, undesirable cosmetic results, increased costs, and, in some cases, mastectomy. Thus, there is a critical need for a navigation system to facilitate accurate tumor excision in nonpalpable breast cancer through real-time patient-specific 3D tracking.

This study …

Intercellular Mitochondrial Transfer Contributes To Microenvironmental Fate Redirection Of Mammary Cancer Cells, Julie Sofie Bjerring

Biomedical Sciences Theses & Dissertations

The dynamic cellular microenvironment, made up of resident cells and various macromolecules, differs markedly across tissues in the body. The multidirectional signals that cells receive from this microenvironment, along with the signaling they send back, heavily influence their physiology and behavior. Recent important findings have further validated this notion as the mammary microenvironment has been shown to suppress tumor progression by redirecting cancer cells to adopt a normal mammary epithelial progenitor fate in vivo. However, the mechanism(s) driving changes in metabolic reprogramming and cancer fate redirection is understudied. The work presented in this dissertation focuses on exploring the impact of …

Simulating The Compound Impacts Of Climate Change And Sea-Level Rise On Coastal Shallow Groundwater Using An Integrated Surface-Subsurface Hydrologic Model, Zhaoyi Cai

Civil & Environmental Engineering Theses & Dissertations

As climate change intensifies and sea levels rise, coastal aquifers become increasingly vulnerable to interacting oceanic and terrestrial processes. This dissertation examines the combined impacts of climate change and sea-level rise (SLR) on coastal shallow groundwater using an integrated surface-subsurface hydrologic model, focusing on the low-lying Little Creek watershed (LCW) in Norfolk, Virginia. The SWAT-MODFLOW model, a coupled system, unifies land surface, streamflow, and groundwater processes, providing a comprehensive framework for watershed-aquifer analysis. Model parameters were derived from U.S. Geological Survey datasets, relevant literature, station records, and technical reports, followed by meticulous calibration. The validated model first simulated baseline groundwater …

Computer Based Modeling For Small E-Vtol Propeller Performance, Ege Konuk

Mechanical & Aerospace Engineering Theses & Dissertations

The emerging field of urban air mobility (UAM) offers a novel transportation method for civil, commercial, and military applications. Vertical take-off and landing (VTOL) configurations present challenges for performance prediction during crucial flight operations. An advanced computational framework for predicting propeller performance in electric vertical takeoff and landing (eVTOL) aircraft during transition flight is essential for future concept designs. This research extends the Blade Element Momentum Theory (BEMT) to model propeller behavior at high incidence angles, crucial for eVTOL operation.

The study begins with a review of tilt-wing/rotor configurations for eVTOLs and tackles the complex aerodynamic phenomena associated with rotors …

Comprehensive Study Of Energy Capturing, Conversion, And Transportation Behaviors In A Piezoelectric Vibration Energy Harvesting System, Bingqi Zhao

Mechanical & Aerospace Engineering Theses & Dissertations

Piezoelectric vibration energy harvester (PEH) is one of the hottest research areas to address renewable energy issues with over 10,000 journal articles published in the last two decades. However, several critical issues, such as the proof mass effects, electrical impedance, mechanical resonance, and energy charging processing, remain open. This dissertation presents a comprehensive study addressing the above issues.

To obtain reliable results, a professional quality flextensional PEH (FPEH) and multiple comprehensive experimental methods were developed, and ANSYS FEM modelling was used. Study of the proof mass effect indicated that the generated voltage linearly increased with the weight ratio of the …

Feasibility Study Of Oyster Shell Filtration Media For Stormwater Pollutants Removal, Sadiq Omer

Civil & Environmental Engineering Theses & Dissertations

The depletion of resources has raised interest in reusing or incorporating by-products into alternative materials. In the effort for net zero emissions, waste reduction, and a circular economy, it is crucial to reinvent the alternative utilization strategy for by-products as construction materials sustainably. This research examines the alternative utilization strategy for oyster shell by-products in regular stormwater pollutant removal best management practices (BMPs).

Numerous research has examined the utilization of oyster shell waste as a construction material in Asia and Europe, specifically focusing on the physical properties of crushed oyster shells as alternatives for aggregates. No studies have been identified …

Roles Of The His-Purkinje System In Long Qt Syndrome Mediated Arrhythmias, Anthony Owusu-Mensah

Biomedical Engineering Theses & Dissertations

Long QT syndrome (LQTS) is a genetic or drug-induced electrophysiological disorder in the heart that prolongs the QT interval on the electrocardiogram. LQTS is present in considerable proportions (1:3000 to 1:5000) of the general population. LQTS has a high incidence of malignant ventricular arrhythmias during physical and emotional stress and is a significant cause of sudden death in younger subjects. This poses a substantial medical burden on the healthcare system in terms of morbidity, mortality, and finances. Despite extensive genetic research into LQTS, the mechanisms underlying spontaneous initiation and maintenance of arrhythmias are not fully understood. Beta-blockers are the standard …

An Interaction Between Mental Integration And Levels Of Automation: An Analytic Approach Applying Systems Factorial Technology, Shelby Kate Scarbrough Long

Psychology Theses & Dissertations

Automation has become nearly ubiquitous in modern society, supporting human performance in personal and professional tasks. Recent works have begun to focus on human-automation performance in speeded perceptual-cognitive tasks using workload capacity analysis, a novel mathematical analysis to measure efficiency of a human-automation team. The present dissertation examined how level of automation and demand for mental integration of information influence human-automation efficiency. Participants performed a multi-element probabilistic decision task with or without the assistance of an automated aid where level of automation and task demand were manipulated. Experiment 1 employed a mixed design with Automation (present vs. absent) and Task …

An Integrated Theoretical Socio-Technical Framework For Implementing Service Robots’ Integration In Healthcare, Sujatha Alla

Engineering Management & Systems Engineering Theses & Dissertations

Healthcare workers, either clinical or non-clinical, are obligated to serve patients. However, lack of a sufficient number of professionals leads to burnout, severe stress, and, consequently, decreased quality of services. In this context, very few countries have been successful in employing service robots to perform dull, dirty, and/or dangerous tasks related to patient wellbeing/healthcare, while most countries are still skeptical about it. As robotics advances, there is an opportunity for healthcare to take advantage of this technology to reduce personnel workload and to reduce the possibility of exposure to contagious pathogens. However, healthcare is a vulnerable environment and requires critical …

Gratings In Optical Waveguides And Lasers, Weida Zhang

Electrical Engineering Theses and Dissertations

Gratings play a crucial role in Distributed Bragg reflector (DBR) lasers, influencing their performance and characteristics. The focus of this work is aimed at the design of DBR lasers that significantly impact the laser's spectral and temporal behavior, making it a key component in optimizing DBR laser functionality.

The SMU developed grating software, compared with commercially available photonics software, has improved accuracy and much smaller computation times. The improved accuracy and reduced computation times compared with commercial photonics software occur because commercial software is typically based on numerical methods such as finite-difference time-domain (FDTD), eigenmode expansion and beam propagation methods …

Inexact Methods For Large-Scale Stochastic Programming, Niloofar Fadavi

Operations Research and Engineering Management Theses and Dissertations

This dissertation addresses the development of inexact methods for solving large-scale stochastic programming problems, with a focus on two-stage and multistage settings. Stochastic programming is a robust approach for managing uncertainty in decision-making, with applications across various domains like supply chain management, power systems, and logistics. However, solving large-scale stochastic programming problems, especially those with a nonlinear structure, is computationally challenging due to the high-dimensional nature of uncertainties and the need for efficient optimization techniques.

This work introduces novel inexact proximal bundle algorithms designed to solve two-stage stochastic quadratic programming problems. The proposed methods utilize dual-based and partition-based approaches to …

Feasibility Of Creating A Non-Profit And Nongovernmental Organization Cybersecurity Incident Dataset Repository Using Osint, Stanley Mierzwa, Iassen Christov

Center for Cybersecurity

Organizations of all types are prone to cybersecurity and information security attacks. Non-Profit Organizations (NPOs) and Non-Governmental Organizations (NGOs) are not exempt from using information technology solutions and, thus, have been the recipient victims of cyber attackers. There exist many areas and venues where data are collected to report back annually on the status and numbers of cybersecurity attacks against many sectors of our society. The Department of Homeland Security (DHS) Cybersecurity and Infrastructure Security Agency (CISA) catalogs sixteen critical sectors that are considered vital to the United States. However, finding where the NPO and NGO community should reside with …

Utilizing A Virtual Firewall Appliance For Introducing And Reinforcing The Concepts And Implementation Of Devices To Improve Security In A Computing Environment, Stanley Mierzwa, Christopher Eng

Center for Cybersecurity

The educational realm of higher education cybersecurity curriculum continues to evolve to provide more opportunities for experiential hands-on and work role-related practical applications of technology solutions. Gaining more excellent competencies is quickly becoming a standard requirement for programs with the National Security Agency Center of Academic Excellence designation. The work roles of cybersecurity include a variety of knowledge, skills, and abilities, depending on the activity category or task. Firewalls have been a staple cybersecurity, network security, and information security device and strategy to protect organization networks and computing environments. This paper will provide details and a description of the effort …

Substrate Interference And Strain In The Second-Harmonic Generation From Mose2 Monolayers, Sudeep Puri, Sneha Patel, Jose Luis Cabellos, Luis Enrique Rosas-Hernandez, Kaitlin Reynolds, Hugh O.H. Churchill, Salvador Barraza-Lopez, Bernardo S. Mendoza, Hiroyuki Nakamura

Physics Faculty Publications and Presentations

Nonlinear optical materials of atomic thickness, such as non-centrosymmetric 2H transition metal dichalcogenide monolayers, have a second-order nonlinear susceptibility (χ⁽²⁾) whose intensity can be tuned by strain. However, whether χ⁽²⁾ is enhanced or reduced by tensile strain is a subject of conflicting reports. Here, we grow high-quality MoSe₂ monolayers under controlled biaxial strain created by two different substrates and study their linear and nonlinear optical responses with a combination of experimental and theoretical approaches. Up to a 15-fold overall enhancement in second-harmonic generation (SHG) intensity is observed from MoSe₂ monolayers grown on SiO₂ when …

Characterization Of A Carbon Fiber Based Broadband Microwave Absorber, Ha Tran, Branimir Pejcinovic, Robert Doneker, Kent Thompson, Adithya Ramachandran

Electrical and Computer Engineering Faculty Publications and Presentations

This paper reports the development and characterization of a novel ultra-wideband microwave absorber material (MAM) based on vertically aligned carbon fibers and ferrite beads. This specific material combination and manufacturing process allows MAM design that is thin, lightweight, and broadband. The material is prepared using a flocking process in which its components are electrostatically deposited on top of an adhesive substrate. Distinct material properties of the substrate and materials layers require characterization done with two separated layers. The microwave absorption characteristics are studied first by rectangular waveguide measurements at X and Ku bands that yield complex electric permittivity and magnetic …

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Burn Cost Modeling For Surface Grinding Optimization, Taiwo Fasae

Dissertations (1934 -)

Surface grinding plays a pivotal role in the machining industry, constituting roughly 25% of all machining operations worldwide. Its precision and efficiency are crucial, particularly in sectors requiring high-quality surface finishes, such as aerospace and semiconductor manufacturing. For thermal damage prevention, traditional approaches to parameter selection use thresholds to exclude burn-prone parameters. However, by omitting the cost of burn, the threshold-exclusion strategy yields outcomes that fail to reflect the true costs of grinding. This dissertation introduces a novel burn cost model that transcends these limitations, offering a more nuanced and cost-effective approach to managing grinding burn. The burn cost model …