Engineering Commons^™

Cost-Effective Strengthening And Automated Inspection Of One-Way Precast Reinforced Concrete Flat Slab Bridges In South Carolina, Laxman Kc

Theses and Dissertations

In South Carolina, the South Carolina Department of Transportation (SCDOT) manages 90% of the state's inventory of 9,400 bridges built in the 1950s. With more than 30% of its bridges having been under-designed and experiencing decades of service deterioration, the implications for public safety, the economy, and the transportation system are significant. To prioritize safety and address these concerns, SCDOT is in the process of conducting thorough inspections of bridges, load ratings, and exploring cost-effective and practical methods to strengthen the bridges and reduce load postings. This study is a part of the multi-year research investigation supported by the SCDOT. …

First Principles Doping Analysis Of Perovskite- And Ruddlesden-Popper-Based Solid Oxide Fuel Cells, Nicholas Alexander Szaro

Theses and Dissertations

Solid oxide fuel cells (SOFCs) have shown significant promise as a high efficiency energy conversion technology. SOFCs are solid-state, high temperature (600 – 1000 °C), and electrochemical conversion devices that can operate with a wide variety of fuels such as hydrogen, syngas, and hydrocarbon feedstocks. The state-of-the-art SOFC is manufactured with a lanthanum strontium manganite (LSM) cathode, an yttria-stabilizedzirconia electrolyte (YSZ), and a nickel on yttria-stabilized-zirconia (Ni/YSZ) cermet anode. LSM || YSZ || Ni/YSZ SOFCs operate at or above 800 °C to achieve sufficient oxide mobility. The high temperatures introduce problems such as long device start-up, particle sintering, and material …

Leveraging Programmable Switches To Enhance The Performance Of Networks: Active And Passive Deployments, Elie Kfoury

Theses and Dissertations

The performance of networks today is drastically affected by: 1) switches equipped with large buffers, referred to as “bloated buffers”: due to the lack of programmability and traffic visibility in legacy switches, operators nowadays configure large buffers statically without considering the characteristics or dynamics of flows. Such buffers increase the delays on packets, causing the Quality of Service (QoS) of networked applications (e.g., voice over IP, web browsing) to degrade; 2) switches forwarding packets on a best-effort basis: traffic crossing a switch is heterogeneous in many ways. Mixing such traffic in a single queue without any QoS measures can drastically …

Revisiting The Volumetric Swing Frequency Response Method For The Determination Of Limiting Mass Transfer Mechanisms Of N2 And O2 In Carbon Molecular Sieve 3k172, Adam Marshall Burke

Theses and Dissertations

Adsorption-based separations processes, along with the adsorbents that enable them, have benefited from a greater particular focus in recent years, following a desire to improve process energy efficiencies and cost economics. One such adsorbent, carbon molecular sieves (CMS), have likewise been a greater focus. CMS materials offer several key practical uses, such as the separation of nitrogen and oxygen, and the removal of carbon dioxide from methane process streams. In order to effectively design and implement an industrial scale process using a CMS material, the behavior of these gases on the chosen material must be known, including the limiting mass …

Extending The Convolution In Graph Neural Networks To Solve Materials Science And Node Classification Problems, Steph-Yves Mike Louis

Theses and Dissertations

The usage of graph to represent one's data in machine learning has grown in popularity in both academia and the industry due to its inherent benefits. With its flexible nature and immediate translation to real life observed objects, graph representation had a considerable contribution in advancing the state-of-the-art performance of machine learning in materials.

In this dissertation proposal, we discuss how machines can learn from graph encoded data and provide excellent results through graph neural networks (GNN). Notably, we focus our adaptation of graph neural networks on three tasks: predicting crystal materials properties, nullifying the negative impact of inferior graph …

Impact Of Dam Height And Grain Size Distribution On Breaching Of Non-Cohesive Dams Due To Overtopping, Heather O'Donal

Theses and Dissertations

The National Inventory of Dams reports 74,400 earthen dams in the United States in 2021, of these dams approximately 27% are considered at high or significant hazard risk, that is dam failure will cause widespread damage and loss of lives. The most frequent cause of dam failure is breaching caused by overtopping. Accurate predictions of breach evolution are thus crucial to determine flood hydrographs for the safety of communities and properties at risk. Laboratory experiments were conducted on non-cohesive, compacted embankments to understand the role of dam height and sediment grain size on breaching caused by overtopping. Dam heights varied …

Predicting Material Structures And Properties Using Deep Learning And Machine Learning Algorithms, Yuqi Song

Theses and Dissertations

Discovering new materials and understanding their crystal structures and chemical properties are critical tasks in the material sciences. Although computational methodologies such as Density Functional Theory (DFT), provide a convenient means for calculating certain properties of materials or predicting crystal structures when combined with search algorithms, DFT is computationally too demanding for structure prediction and property calculation for most material families, especially for those materials with a large number of atoms. This dissertation aims to address this limitation by developing novel deep learning and machine learning algorithms for effective prediction of material crystal structures and properties. Our data-driven machine learning …

A Systems Approach To Design And Plan Sustainable Antifragile Infrastructure Based On Aggregate Footprint And Satisfaction, Farboud Khatami

Theses and Dissertations

The concepts of robustness and sustainability in planning and design of water and energy infrastructures have been extensively explored in previous research, primarily focusing on system reliability, environmental considerations, and economic aspects. This study aims to broaden the understanding of these concepts by offering comprehensive frameworks that capture the essence of robustness and sustainability at two distinct levels.

The first level of investigation focuses on the performance of infrastructure networks during natural disasters. Traditionally, this has been addressed using reliability, resilience, and vulnerability metrics. However, these methods rely on static, deterministic, and non-stationary data, which is inadequate when dealing with …

Automated Fiber Placement Through Thickness Defect Stacking Optimization, Noah Christopher Swingle

Theses and Dissertations

In its 2022 commercial market outlook, Boeing forecasted an 80% increase in the global fleet through 2041 compared to 2019 pre-pandemic levels. This sharp rise in demand will drive pressure onto airframe manufacturers to ramp up production and find more efficient ways to design and manufacture airplanes. Complicating this challenge is the industry’s recent transformation from traditional metal-based airframes towards hybrid composite-metal aircraft. While composites have been used in aviation for decades, aircraft manufacturers are still struggling to design and manufacture quality parts at a high rate. Automated Fiber Placement (AFP) is one of the main manufacturing techniques used to …

Dechlorination Of Waste Pvc (Polyvinyl Chloride) Using Hydrothermal Liquefaction Method, Vahab Ghalandari

Theses and Dissertations

In 2019, waste plastic production in the United States (U.S.) amounted to approximately 73 million metric tons. Projections indicate that by 2030, the generation of waste plastic in the U.S. will increase to nearly 90 million metric tons, and by 2060, it is expected to surpass 140 million metric tons. One prominent type of waste plastic is polyvinyl chloride (PVC), characterized by its high chlorine content, making it a halogenated plastic. This dissertation presents a comprehensive investigation of the dechlorination of waste PVC (WPVC) through various hydrothermal liquefaction (HTL) methods to produce environmentally friendly solid and liquid products. In this …

An Ml Based Digital Forensics Software For Triage Analysis Through Face Recognition, Gaurav Gogia, Parag H. Rughani

Journal of Digital Forensics, Security and Law

Since the past few years, the complexity and heterogeneity of digital crimes has increased exponentially, which has made the digital evidence & digital forensics paramount for both criminal investigation and civil litigation cases. Some of the routine digital forensic analysis tasks are cumbersome and can increase the number of pending cases especially when there is a shortage of domain experts. While the work is not very complex, the sheer scale can be taxing. With the current scenarios and future predictions, crimes are only going to become more complex and the precedent of collecting and examining digital evidence is only going …

Genetic Algorithm Theory In Simulation Programs As A Tool For Improving The Environmental Performance Of Office Buildings, Somaia Mohamed Arafa, Esraa Mohamed Elazab, Nanees Abd Elhamid Elsayyad

Mansoura Engineering Journal

Globally, a large proportion of a building's energy is consumed to achieve thermal comfort, as promoting energy efficiency and environmental sustainability of buildings is an important global goal. Therefore, the new building regulations are geared explicitly toward energy-saving projects. However, there are usually many competitive priorities, such as maximizing energy use in office buildings, leading to the complex multi-objective optimization topic. The main objective of this research was to reduce the energy consumed for cooling load in the office buildings in the city of Cairo, which is located in a hot desert climate. This was achieved by optimizing ten different …

Digital Health Design For Improving Treatment Decisions, Akanksha Singh

Theses and Dissertations

In the age of artificial intelligence and large datasets, information retrieval by querying large databases is an impossible task for the common user due to the information overload. Recommender Systems (RS) for commercial applications like YouTube, Amazon and Netflix were designed to support users by finding items of interest based on their user profiles and various filtering techniques. Health Recommender Systems (HRS) is a category of RSs that provides immense opportunities for application across several healthcare domains and contexts including treatment decision support. Unlike RS applications that focus on analyzing consumer choices, a key differentiator for HRS applications is the …

Gpu-Enabled Genetic Algorithm Optimization And Path Planning Of Robotic Arm For Minimizing Energy Consumption, Yichuan Cao

Theses and Dissertations

The robotic arm represents a complicated mechanical system and advanced engineering principles in robotics, enabling precise and efficient manipulation and interaction with objects in a variety of applications, such as manufacturing, healthcare, space exploration, and other industries. In most cases, energy consumption of robotic tools has been given little consideration due to their perceived insignificance compared to the benefits they offer. However, the increasing capacity demands of factories and the expanding use of robotic arms necessitate careful evaluation and reduction of energy consumption. In this regard, given a task configuration, adjusting the arm's movement path emerges as one of the …

Streamwise And Vertical Dispersal Of Tracer Stones From A Continuously Supplied Source, Amanda Grace Balkus

Theses and Dissertations

Individual movement of sediment grains is oftentimes studied with the use of tracer stones. Studies performed both in the field, in the laboratory and with numerical models involve installing a patch of stones (tracers) on the bed surface and rarely deep in the deposit. Once installed, particle displacement is monitored over time scales varying from one flood to several years. These studies are useful, for example, to study bedload transport dynamics, understand contaminant fate and transport as well as to identify and define stream restoration practices (e.g. quality of fish habitat). Here we use a vertically continuous model to study …

Implementation Of A 3d Laser Profiler System Into A Non-Contacting Method For Rnt & Stress Measurements, Caio Neto Penna

Theses and Dissertations

Continuous welded rail (CWR) is susceptible to the development of internal forces in the rail due to thermal effects that can lead to track buckling. Railroads typically deal with the internal stresses in the rail through the inspection of the rail neutral temperature (RNT) which is the temperature at which the internal force is zero. The existing methods in the industry to measure RNT are contacting, destructive, disruptive to railroad operations, and ineffective. The proposed concept is a promising non-contacting, non-disruptive and reference-free technique to measure RNT and the stress state in the rail. The method is based on the …

Assessment And Development Of Collaboration Framework For Less-Than-Truckload Carriers, Bhavya Padmanabhan

Theses and Dissertations

The growth of e-commerce is changing consumer expectations for delivery services. Competition is making “faster and cheaper” a nonnegotiable part of success; hence, retailers are seeking carriers that can deliver with ever-shorter lead times and at the lowest possible cost. In this environment, large carriers have a competitive advantage due to their market power. For small-to-medium-sized less-than-truckload (LTL) carriers to stay in business, they must improve their efficiency and lower cost. A potential strategy to achieve these goals is to collaborate with other carriers. In collaborating, carriers would exchange and perform certain jobs for each other to lower their transportation …

Liquid Cooling System For A High Power, Medium Frequency, And Medium Voltage Isolated Power Converter, Hooman Taghavi

Theses and Dissertations

Controlling and transforming electrical power from one form into another is the Primary function of the power electronics systems that are employed today. These systems have a wide variety of applications and are utilized in things like industrial automation, electric cars, consumer electronics, and renewable energy systems, among other things. The functioning of power electronics systems results in the production of a substantial quantity of heat, despite the fact that these systems are very dependable and efficient. This heat must be dispersed to preserve system performance and avoid component damage. By ensuring that the working temperature of the components stays …

Conceptual Design And Preliminary Safety Analysis Of A Proposed Nuclear Microreactor For Mobile Application, A. S. M. Fakhrul Islam

Theses and Dissertations

Conceptual design and preliminary safety analysis of a proposed helium-cooled Micro Nuclear reactor In ONe megawatt (MINION) thermal output is done through three-dimensional computational analysis. Compared with the conventional high temperature gas-cooled reactors (HTGR) that use tri-structural or bi-structural isotropic (TRISO or BISO) fuel particles, MINION uses traditional clad fuel pellets. This greatly simplifies the core design and allows for a substantially more compact design thanks to the fuel’s signif-icantly higher U-235 atom density. Uranium carbide (UC) enriched up to 19.75% in U-235 is used as fuel. In the power-flattened design, U-235 enrichment varies radially between 19.75% and 10.5% in …

The Effect Of Microstructural Defects And Geometrical Features On Fatigue Behavior Of Superelastic Nitinol Wires, Parisa Shabani Nezhad

Dissertations (1934 -)

Nitinol is an alloy of nickel and titanium, which exhibits outstanding functional properties, such as shape memory and superelastic behavior. Superelastic nitinol wires exhibit recoverable strains that are significantly greater than traditional alloys. In most of its applications, nitinol is exposed to cyclic loads, which results in functional and/or structural fatigue that ultimately leads to failure. The classical fatigue theories do not appropriately address the fatigue performance of superelastic nitinol due to the complex nature of the martensitic transformation. It has been shown that the main fatigue crack initiation sites, other than surfaces, are microstructural inhomogeneities such as voids and …

Mapping Ecotourism Potential In Bangladesh: The Integration Of An Analytical Hierarchy Algorithm And Geospatial Data, Muhallil Abtahee, Afra Anika Islam, Md. Nazmul Haque, Hasan Zonaed, Samiha Mahzabin Ritu, S. M. Imdadul Islam, Atiq Zaman

Civil Engineering Faculty Publications

The significance of ecotourism has been increasing due to its potential for biodiversity preservation, economic advancement, and the promotion of sustainability awareness. In this research, geospatial analysis and the Analytical Hierarchy Process (AHP) was employed to identify feasible ecotourism sites in Bangladesh. The study applied Geographical Information System–Remote Sensing (GIS-RS) parameters and weighted overlay techniques for selected ecotourism characteristics, such as natural attractiveness, topographic features, accessibility, proximity to facilities, and community characteristics. The study found that a significant proportion (around 44%) of Bangladesh’s land exhibits high potential for ecotourism. Cox’s Bazar, Chittagong, and Rangamati are particularly favorable ecotourism locations. However, …

Deep Cnn-Based Automated Optical Inspection For Aerospace Components, Shashi Bhushan Jha

Doctoral Dissertations and Master's Theses

ABSTRACT

The defect detection problem is of outmost importance in high-tech industries such as aerospace manufacturing and is widely employed using automated industrial quality control systems. In the aerospace manufacturing industry, composite materials are extensively applied as structural components in civilian and military aircraft. To ensure the quality of the product and high reliability, manual inspection and traditional automatic optical inspection have been employed to identify the defects throughout production and maintenance. These inspection techniques have several limitations such as tedious, time- consuming, inconsistent, subjective, labor intensive, expensive, etc. To make the operation effective and efficient, modern automated optical inspection …

Resilience Model For Teams Of Autonomous Unmanned Aerial Vehicles (Uav) Executing Surveillance Missions, Robert Koeneke

Doctoral Dissertations and Master's Theses

Teams of low-cost Unmanned Aerial Vehicles (UAVs) have gained acceptance as an alternative for cooperatively searching and surveilling terrains. These UAVs are assembled with low-reliability components, so unit failures are possible. Losing UAVs to failures decreases the team's coverage efficiency and impacts communication, given that UAVs are also communication nodes. Such is the case of a Flying Ad Hoc Network (FANET), where the failure of a communication node may isolate segments of the network covering several nodes. The main goal of this study is to develop a resilience model that would allow us to analyze the effects of individual UAV …

Inventory-Responsive Donor-Management Policy: A Tandem Queueing Network Model, Taozeng Zhu, Nicholas Teck Boon Yeo, Sarah Yini Gao, Gar Goei Loke

Research Collection Lee Kong Chian School Of Business

Problem definition: In the blood-donor-management problem, the blood bank incentivizes donors to donate, given blood inventory levels. We propose a model to optimize such incentivization schemes under the context of random demand, blood perishability, observation period between donations, and variability in donor arrivals and dropouts. Methodology/results: We propose an optimization model that simultaneously accounts for the dynamics in the blood inventory and the donor’s donation process, as a coupled queueing network. We adopt the Pipeline Queue paradigm, which leads us to a tractable convex reformulation. The coupled setting requires new methodologies to be developed upon the existing Pipeline Queue framework. …

Extending The Service-Life Of Bridges Using Sustainable And Resilient Abutment Systems: An Experimental Approach To Electrochemical Characterization Of Lightweight Mechanically Stabilized Earth, Fariborz M. Tehrani, Kenneth L. Fishman, Farmehr M. Dehkordi

Mineta Transportation Institute

Bridges are critical components of transportation infrastructure. This research addresses the need to extend the service life of bridges by improving the safety and reliability of bridge abutments and reducing their life-cycle cost and footprints. Mechanically stabilized earth (MSE) is a known strategy to enhance the economy and performance of bridge abutments. In addition, the application of rotary-kiln-manufactured lightweight aggregate backfills improves the performance of MSE bridge abutments with a leaner structural system. Such improvements include a reduction of structural demands due to a lower density, free drainage of granular materials, a high internal friction angle, less settlement with no …

Electrical Vehicle Charging Infrastructure Design And Operations, Yu Yang, Hen-Geul Yeh

Mineta Transportation Institute

California aims to achieve five million zero-emission vehicles (ZEVs) on the road by 2030 and 250,000 electrical vehicle (EV) charging stations by 2025. To reduce barriers in this process, the research team developed a simulation-based system for EV charging infrastructure design and operations. The increasing power demand due to the growing EV market requires advanced charging infrastructures and operating strategies. This study will deliver two modules in charging station design and operations, including a vehicle charging schedule and an infrastructure planning module for the solar-powered charging station. The objectives are to increase customers’ satisfaction, reduce the power grid burden, and …

Jme 4110: Door Cycling Station, Briana Kagy, Alexander Clark, William Todd, Seth Flamm

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The objective of this project was to design and build a door cycling station to be used for fatigue testing commercial refrigerator doors, including the door gaskets, hinges, and handles. The system must be low maintenance and reliable for at least two million cycles, and it must fit within the provided budget. The design concept includes a rodless pneumatic cylinder and a system of wear-resistant ropes, eyebolts, and pulleys.

Learning Deep Time-Index Models For Time Series Forecasting, Jiale Gerald Woo, Chenghao Liu, Doyen Sahoo, Akshat Kumar, Steven Hoi

Research Collection School Of Computing and Information Systems

Deep learning has been actively applied to time series forecasting, leading to a deluge of new methods, belonging to the class of historicalvalue models. Yet, despite the attractive properties of time-index models, such as being able to model the continuous nature of underlying time series dynamics, little attention has been given to them. Indeed, while naive deep timeindex models are far more expressive than the manually predefined function representations of classical time-index models, they are inadequate for forecasting, being unable to generalize to unseen time steps due to the lack of inductive bias. In this paper, we propose DeepTime, a …

Imitation Improvement Learning For Large-Scale Capacitated Vehicle Routing Problems, The Viet Bui, Tien Mai

Research Collection School Of Computing and Information Systems

Recent works using deep reinforcement learning (RL) to solve routing problems such as the capacitated vehicle routing problem (CVRP) have focused on improvement learning-based methods, which involve improving a given solution until it becomes near-optimal. Although adequate solutions can be achieved for small problem instances, their efficiency degrades for large-scale ones. In this work, we propose a newimprovement learning-based framework based on imitation learning where classical heuristics serve as experts to encourage the policy model to mimic and produce similar or better solutions. Moreover, to improve scalability, we propose Clockwise Clustering, a novel augmented framework for decomposing large-scale CVRP into …

Estimation Of Recursive Route Choice Models With Incomplete Trip Observations, Tien Mai, The Viet Bui, Quoc Phong Nguyen, Tho V. Le

Research Collection School Of Computing and Information Systems

This work concerns the estimation of recursive route choice models in the situation that the trip observations are incomplete, i.e., there are unconnected links (or nodes) in the observations. A direct approach to handle this issue could be intractable because enumerating all paths between unconnected links (or nodes) in a real network is typically not possible. We exploit an expectation–maximization (EM) method that allows dealing with the missing-data issue by alternatively performing two steps of sampling the missing segments in the observations and solving maximum likelihood estimation problems. Moreover, observing that the EM method could be expensive, we propose a …