Engineering Commons^™

Devices And Dining: A Cross-Cultural Analysis Of Mobile Device Use In Italian And American Restaurants, O'Malley Jenkins

Senior Theses

The field of technology ethics has seen increasing growth and interest over the years. Many have begun to consider the impacts of technology’s use and whether it is being employed in a healthy manner by users. However, there has been limited investigation into whether the ways in which technology use varies across cultures. This study begins to address this gap by researching Italian and American device usage in fast food settings. Non-participant naturalistic observations were used to record data for 89 Italian and 88 American customers of fast food restaurants. Analysis of the collected data indicates that Americans use their …

A Comprehensive Ml And Ai Framework For Intersection Safety: Assessing Contributing Factors, Surrogate Safety Measures, Non-Compliance Behaviors, And Cost-Inclusive Methodology, Deep Patel

Theses and Dissertations

Intersection safety, particularly in traffic management, has emerged as a pressing concern due to its substantial contribution to road crashes and fatalities. In recent years, understanding road users' behavior and conflicts at intersections has become essential for evaluating traffic safety. According to the Federal Highway Administration (FHWA), in 2020, over 50% of fatal and injury crashes occurred at or near intersections, necessitating further investigation. This study addresses this issue through an innovative blend of comprehensive literature review, advanced machine learning algorithms, artificial intelligence (AI) technologies, surrogate safety measures (SSMs), non-compliance behavior, and emphasizing the economic aspects of traffic incidents. First, …

Investigation Of The Operational Benefits Of Flipped Left Diamond Interchange, Nazmus Salehin Asif,

Theses (2016-Present)

Interchange is an important element to accommodate the critical movement between arterials and freeways. To operate efficiently, innovative interchange designs have been suggested by transportation professionals. Recently, an innovative interchange design called flipped left diamond interchange (FLDI) design has been proposed. That aims to increase capacity and improve efficiency by flipping the left-turn lanes in opposing directions, eliminating conflicts between opposing left-turn movements. So, the signal timing of the left turn movements and through movements are independent which indicates the signal timing of these movements can be determined based on their volume. Due to this independence, any signal timing sequences …

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 …

Ridds: Removal Of Irregular Debris Using Double Nets, Kayann Coote

Doctoral Dissertations and Master's Theses

The quantity of debris in Earth’s orbit is increasing at an alarming rate, and without a sustainable solution, this will detriment the space environment, impacting the future of space travel and space traffic management. While numerous debris removal concepts and designs have been proposed, very few have made it to actual flight tests, and none can remove debris at a fast enough rate to stop debris growth. For debris currently in orbit, most proposed systems are costly on a large scale and cannot adapt to the wide variety of debris shape and geometry and tumbling. The purpose of the proposed …

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 …

Durability Assessment And Service Life Prediction Of Concrete In Extreme Aggressive Environment, Mohamed Ismail

Doctoral Dissertations and Master's Theses

The objective of this research is to enhance the durability of newly constructed structural elements by assessing the performance of various concrete mixes for chloride resistance. The study focuses on establishing and developing correlations between chloride diffusion rates and concrete resistivity. By identifying these correlations and based on the target service life, the research aims to set appropriate thresholds for Surface Resistivity (SR) and Bulk Resistivity (BR) tests, which will be used to qualify concrete mixes used in in extremely aggressive chloride environments. To achieve these objectives, the research uses a systematic approach that combines experimental testing with analytical modeling. …

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 …

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 …

Integrating Digital Twin Technology For Real Time Blockage Detection In Water Cooled Electronics, Richard Scott Hainey Jr.

Theses and Dissertations

This paper presents a culmination of research into integrating Digital Twin (DT) technology in water-cooled electronic systems to improve system reliability by detecting faults in the cooling system that maintains the proper operation of heat-producing electronic components and systems. A DT is a virtual representation of a physical twin (PT). This PT can represent real-world systems, individual components, or processes. Using the DT, operators can gain insight into the behavior and characteristics of the PT, thereby facilitating informed decisions to improve its health and optimize processes. The DT system is designed to detect obstructions forming in the waste heat-producing components …

Investigation And Comparative Analysis Of Onset Of Nucleate Boiling (Onb) In A Narrow Rectangular Channel In Microgravity And Earth Gravity Environments, Fahim Foysal

Theses and Dissertations

Understanding the onset of nucleate boiling (ONB) in different gravitational environments is crucial for a wide variety of industrial and space applications of flow boiling systems for thermal management. This thesis provides a comparative analysis of ONB in both microgravity (µg) and Earth gravity (1g) environments, with the aim of identifying the key differences. NASA’s experimental facility called Flow Boiling and Condensation Experiment (FBCE) equipped with Flow Boiling Module (FBM) was used for both the experiment onboard the International Space Station (ISS) and on Earth. The experiment was conducted in a rectangular channel of 5mm (depth) ×2.5 mm (width) ×114.6 …

Investigating Electrochemical Performance And Interfacial Stability Of Solid-State Lithium Metal Batteries: A Study Of Hybrid Polymer-Ceramic Electrolyte Systems, Ziba Rahmati

Theses and Dissertations

Solid-state batteries (SSBs) are emerging as a promising energy storage technology, surpassing traditional liquid electrolyte (LE) counterparts in performance and safety. A critical component in SSBs is the solid-state electrolyte (SSE), which plays a pivotal role in safety, efficiency and stability. SSEs, including sulfides, halides, oxides, and polymers, present distinct advantages and challenges compared to LEs. Among these, oxide-based SSEs are particularly attractive for their balance in ionic conductivity and chemical stability.

This study addresses key challenges related to interfacial stability and electrochemical performance in SSBs by focusing on hybrid polymer-ceramic electrolyte systems. A major challenge to such a SSB …

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 …

Experimental Comparison Of Open Chamber Spark Plug And Passive Prechamber Spark Igniters On The Combustion Of Fumigated Natural Gas For Heavy Duty Engine Applications, John Richard Valla

Master's Theses (2009 -)

Methane the primary component of natural gas, has 80 times the global warming potential of CO2. As a result methane emissions regulations have rapidly increased in recent years. This posses a challenge for heavy duty spark ignited (SI) natural gas engine OEMs, in efforts to reduce methane and other criteria pollutant emissions such as NOx. Heavy duty natural gas engine OEMs are pushing engine efficiency and reducing emissions by running higher compression ratios and leaner air fuel ratios. This reduces fuel consumption and combustion temperature which decreases NOx emissions, but tends to increase methane emissions. Unfortunately, lean high compression ratio …

Adaptive Control And Estimation Of The Center Of Mass Of A 5-Degree-Of-Freedom Spacecraft Testbed, Pol Fontdegloria Balaguer

Doctoral Dissertations and Master's Theses

In space applications, on-ground experimentation is an essential step in control algorithm validation before real mission application. However, on-ground conditions greatly differ from space ones, where satellites operate under extremely low gravity and friction conditions. A common way to simulate these conditions is with air-bearing-based testbeds. These testbeds reduce friction significantly to almost space-like conditions. Air-bearing technology can provide virtually frictionless translational and rotational motion. However, when frictionless rotational motion is achieved, the testbed becomes highly sensible gravity torque. This external torque is produced by the offset between the predetermined geometrical center of rotation (CoR) and the center …

Effect Of Storage Time And Temperature On Aggregation Of Alzheimer's Disease Amyloid-Β Protein, Amy Veihdeffer

Theses and Dissertations

Amyloid-β protein (Aβ) is widely studied due to its key role in Alzheimer’s disease (AD) pathology. One characteristic of patients suffering from AD is the deposition of amyloid plaques comprised of Aβ aggregates, which are associated with synapse damage. Thus, studying Aβ aggregation and aggregation inhibition may provide pathological and therapeutic insights. Aggregation of Aβ is a nucleation dependent process that may be influenced by the presence of pre-formed Aβ aggregate seeds that can facilitate formation of protein aggregates. These seeds may appear during preparation or storage of monomer, posing impact on experiments that study the aggregation process and the …

Interpretation Of Surface Roughness Of Stainless Steel 316l In Laser Powder Bed Fusion Additive Manufacturing, Tianyu Zhang

Theses and Dissertations

Laser Powder Bed Fusion (L-PBF), a widely used metal additive manufacturing (AM) method, is emerging as a key technology in the modern manufacturing industry. Its applications span across aerospace, transportation, energy, and biomedical industries, aiming to maximize product functionality, quality, and manufacturing efficiency.

Surface roughness, an important measure of product quality, impacts geometrical tolerances and plays a critical role in mechanical and functional properties. Although post-process techniques such as machining, shot peening, and chemical processing can be used to refine surfaces, internal surfaces in complex geometries remain difficult to treat, limiting part performance due to undesired surface features. The …

The Accurate Conversion Of Biological Experiments From Cesium Irradiation To X-Ray Irradiation: The Significance, Problems, And The Future Of Experimental Radiation Research, Gretchen Carpenter

Dartmouth College Master’s Theses

Preclinical small animal irradiation studies, once conducted on Cesium irradiators, are increasingly being performed with X-ray-based irradiators. The transition stems from concerns regarding national security risks, making X-ray irradiators which are compact and easy to operate an enticing alternative. However, questions regarding the relative biological effectiveness between the two sources have revealed a lack of adequate dosimetric characterization of X-ray beams, standardized protocol for dose calibration, and thorough understanding of experimental biological parameters. A literature review conducted on orthovoltage irradiators has revealed that there are over 54 different types of beam structures used, a dramatic departure from the one uniform …

Hardware Control Unit For Trusted Program Verification System, Jake Owen Alt

Master's Theses

Trust in the underlying hardware is the foundational step towards trusting the correctness and integrity of a software application. However, verifying that today's extremely complex processors work exactly as intended has not been feasible, as evidenced by several recent hardware bugs. Trustworthy, formally verified processors currently forego intricate performance enhancements such as out-of-order execution, hampering them substantially versus their less secure counterparts.

The Containment Architecture with Verified Output (CAVO) system solves this problem by isolating the host system and requiring the result of each instruction to be validated by a small, trusted hardware module called the Sentry. Any transmissions to …

Temporal Forecasting Of High-Rate Dynamic Using Physics-Informed Machine Learning And Hardware-Software Co-Design, Puja Chowdhury

Theses and Dissertations

Due to aging, fatigue, corrosion, and even natural disasters; the health of the structure is prone to degradation throughout its service life. The explosively-fast growing efforts on Structural health monitoring (SHM) always try to exploit different aspects of the automation of damage detection, localization, and prognosis tasks. One of the main challenges is the hardware and software co-design to implement the model in real-life situations. On the other hand, the fast-advancing artificial intelligence draws the researchers' attention to adopt different data-driven approaches in this field. This brings other challenges like domain-specific model adaptation, data bias, data scarcity, model validation by …

Sex Differences In Active Avoidance And Neural Circuit Mechanisms In Contextual Fear Generalization, Carly Vincent

Theses and Dissertations

The current studies were aimed to investigate two behavioral hallmarks of anxiety and stress-related disorders, avoidance responses and the over-generalization of fear. In the first set of studies, active avoidance and extinction learning, that parallels exposure therapy in preclinical rodent models, were used. It is known that stress can influence aversive learning and extinction training, which can result in poor extinction retention. However, it is not well understood how the stress response is facilitating extinction resistance in active avoidance learning across sexes. Therefore, the first set of studies aimed to investigate the role of biological sex and glucocorticoid receptor (GR) …

Design And Application Of Redox-Mediated Flow Electrode Electrodialysis For Ion Removal And Recovery, Rongxuan Xie

Theses and Dissertations

To meet the growing demand for freshwater driven by population growth and rising living standards, the first desalination plants were established in the late 1950s. As energy costs have risen over time, research has increasingly focused on reducing the overall cost of water treatment. Electrodialysis (ED), which facilitates the migration of anions and cations across ion exchange membranes under the influence of an electric field, has gained significant attention as a treatment method for saline water and brine due to its simplicity, low cost, and scalability. However, its traditional batch operation mode and the potential for generating flammable gases have …

Autonomous Real-Time Model Updating Within Digital Twin Frameworks For Thermal Systems, Braden Robert Priddy

Theses and Dissertations

As engineering systems increase in scale and complexity in the era of the Fourth Industrial Revolution, data-driven solutions will become essential in enabling the next generation of these systems. One of the trending tools that can aid in this transition is digital twins. As physical systems degrade throughout their life cycles, their behavior also changes. Digital twins use data assimilation to continuously update virtual models to represent the current state of their physical counterparts. A reliable digital twin can be leveraged by a system operator to perform diagnostics, optimize, and tests without ever needing the physical system. However, implementing effective …

Advancement Of The Zinc Ion Battery: Polymer Electrolyte And Electrode Development For Aqueous Zinc-Ion Batteries, Roya Rajabi

Theses and Dissertations

Rechargeable aqueous zinc-ion batteries (ZIBs) have garnered significant attention in recent years as a promising candidate for stationary large-scale energy storage due to their distinct safety features and cost-effectiveness compared to conventional lithium-ion batteries. Despite their great potential, ZIBs are currently facing critical challenges for commercialization, including poor cycle stability at low discharge rates, lower energy density (Wh/kg) and higher self-discharge rate. These issues must be addressed for them to become a viable energy storage solution. The above challenges are fundamentally rooted in the bulk properties of electrolytes and interactions with electrodes, such as; 1) formation of insulating layered double …

Augmented Reality (Ar) And Virtual Reality (Vr)-Based Data Visualization Frameworks For The Manufacturing Industry, Nitol Saha

Theses and Dissertations

Industry 4.0 is transforming the manufacturing industry by integrating digital technologies throughout the production lifecycle, leading to the development of smart factories. The integration of Augmented Reality (AR) and Virtual Reality (VR) alongside smart manufacturing is transforming traditional industry practices by establishing a robust cyber-physical infrastructure, enhanced data visualization, and improved task execution. This thesis aims to develop AR and VR-based data visualization frameworks for the manufacturing industry, focusing on detailed implementation strategies, initial results, and key findings of these frameworks. One major focus of these frameworks is the generalization of the technological assets so that these frameworks can be …

Electroless Deposition And Galvanic Displacement For The Control Of Supported Nanoparticle Size And Composition, Haiying Zhou

Theses and Dissertations

Catalyst performances can be greatly affected by properties such as particle size, composition, geometry, and cleanliness of the active surface. To achieve optimal catalytic performance, appropriate synthesis methods are required to synthesize the desired structures. Supported metal particle catalysts are usually prepared by impregnation and precipitation methods in industry. Although these two methods are simple, they exhibit poor control over surface morphology, leading to a wide particle size distribution and uncontrolled distribution of different metal components. In this dissertation, three topics on controlling surface morphology are discussed.

For structure sensitive reactions, reactivity and selectivity can be strongly affected by particle …