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Articles 6271 - 6300 of 77828

Full-Text Articles in Engineering

Molecular-To-Continuum Scale Modeling Of Aerosols: Atmospheric Application And Beyond, Ella Ivanova May 2024

Molecular-To-Continuum Scale Modeling Of Aerosols: Atmospheric Application And Beyond, Ella Ivanova

Dissertations

Aerosol modeling is critical for various applications, such as climate forecasting, air quality, and human health impact assessment. During their lifetime, aerosols undergo a complex evolution, usually divided into several stages — formation, processing, transport, and removal — that occur on different scales. Thus, the choice of modeling methods depends on the stage considered. For example, certain stages of particle formation may require nano-scale modeling while aerosol-cloud interactions span from microscale to mesoscale. This study examines the modeling of aerosol behavior over a wide range of scales, from nano to microscale, with implications to mesoscale.

This dissertation focuses on two …


Microplastic Abundance And Removal In Stormwater Using Green Infrastructure, Meghana Parameswarappa Jayalakshmamma May 2024

Microplastic Abundance And Removal In Stormwater Using Green Infrastructure, Meghana Parameswarappa Jayalakshmamma

Dissertations

Microplastics (MPs) are increasingly recognized as a pervasive environmental contaminant, conveying other contaminants, accumulating in aquatic organisms, and posing ecological risks. The existing research has primarily focused on MPs in wastewater treatment plant effluents in surface waters. However, the role of stormwater systems in MP transport has been less explored. Given the rise in MPs from urban sources, stormwater runoff from urban areas may serve as a critical conduit for transporting land-based MPs into aquatic environments. Green infrastructures (GIs) have been recognized for mitigating flooding and improving water quality from minor storms by trapping stormwater pollutants. Yet, the capability of …


Reproducible Fluid Structure Interaction For Complex Flows In Engineered Systems, Allen Prasad Varghese May 2024

Reproducible Fluid Structure Interaction For Complex Flows In Engineered Systems, Allen Prasad Varghese

Dissertations

This dissertation focuses on the application of numerical models to study Fluid Structure Interaction (FSI) in the industrial context. The emphasis is on a series of case studies belonging to practical applications in design and manufacturing and that are solved by a synergistic use of theoretical and computational models. The first study looks into the hydrodynamic actions experienced by vibrating slender structures immersed in viscous fluids near the free surface. This study case is relevant to applications such as, for example, marine propulsion, micro-electro-mechanical systems, and atomic force microscopy. The hydrodynamic problem is governed by three parameters, namely the frequency, …


Development Of Super Hydrophobic Membranes And Their Applications, Sumona Paul May 2024

Development Of Super Hydrophobic Membranes And Their Applications, Sumona Paul

Dissertations

Effective liquid phase separation is vital across industries, especially in aviation, chemicals, fuels, and textiles. Membrane technology offers advantages over traditional methods like distillation, with low energy consumption and protection for heat-sensitive molecules. Membrane performance is assessed based on factors such as materials, surface modification, and interactions. This research targets superhydrophobic membranes for liquid-liquid filtration and antiwetting omniphobic membranes for membrane distillation, focusing on properties like contact angle and thermal resistance.

This study presents a highly hydrophobic membrane achieved by immobilizing carbon nanotubes (CNTs) onto a PTFE microfiltration membrane. It's designed for dewatering organic-water mixtures with trace water content via …


Effects Of Exoskeletal-Assisted Walking Rehabilitation On Gait Of Patients Post Stroke, Archisha Kanchan May 2024

Effects Of Exoskeletal-Assisted Walking Rehabilitation On Gait Of Patients Post Stroke, Archisha Kanchan

Theses

Stroke can have detrimental effects on one's body. Its symptoms can range from lightheadedness to blurred vision to body paralysis. One of the more common effects of stroke is difficulty walking where many of the patients who have suffered from stroke are unable to ambulate fully. To mitigate gait difficulties, patients typically follow through with various kinds of physical therapy to help with their gait movements. Recently, robotic exoskeleton (RE) walking therapy has been used as a more innovative approach to gait rehabilitation, in conjunction with other physical therapy session techniques. However, studies involving RE therapy within the stroke population …


The Next Strike: Pioneering Forward-Thinking Attack Techniques With Rowhammer In Dram Technologies, Nakul Kochar May 2024

The Next Strike: Pioneering Forward-Thinking Attack Techniques With Rowhammer In Dram Technologies, Nakul Kochar

Theses

In the realm of DRAM technologies this study investigates RowHammer vulnerabilities in DDR4 DRAM memory across various manufacturers, employing advanced multi-sided fault injection techniques to impose attack strategies directly on physical memory rows. Our novel approach, diverging from traditional victim-focused methods, involves strategically allocating virtual memory rows to their physical counterparts for more potent attacks. These attacks, exploiting the inherent weaknesses in DRAM design, are capable of inducing bit flips in a controlled manner to undermine system integrity. We employed a strategy that compromised system integrity through a nuanced approach of targeting rows situated at a distance of two rows …


Strawberry Nectar Preservation Through Innovative Techniques And Energy Evaluation For High-Pressure Processing, Caterina Scaioli May 2024

Strawberry Nectar Preservation Through Innovative Techniques And Energy Evaluation For High-Pressure Processing, Caterina Scaioli

Theses

Strawberries are universally adored by people of all ages, owing to their richness in vitamins, nutrients, and antioxidants, offering myriad health benefits, including combating free radicals. However, despite their popularity, strawberry juices or nectars are not commonly found in markets due to their delicate structure, which makes them prone to rapid deterioration of their prized qualities and vibrant red color. In the food industry, preventing browning and nutrient deterioration are often the primary challenges faced when processing red juices. Traditional preservation methods, such as pasteurization, are inadequate in maintaining their freshness. The focus of this study is to explore alternative …


Machine Learning Based Analysis Of Civil Infrastructure In The Presence Of Sparse Data, Megan Butcher May 2024

Machine Learning Based Analysis Of Civil Infrastructure In The Presence Of Sparse Data, Megan Butcher

Doctoral Dissertations and Master's Theses

The high computational cost of estimating engineering demand parameters (EDPs) via finite element (FE) models, which incorporate uncertainties in earthquake events and material properties, limits the application of the Performance-Based Earthquake Engineering (PBEE) framework. Previous efforts to replace FE models with surrogate models have typically focused only on building parameters, necessitating re-training for new, unseen earthquakes. This paper introduces a machine learning-based surrogate model framework that addresses both earthquake and material parameter uncertainties to predict responses for unseen seismic events. Earthquakes are characterized by their projections on an orthonormal basis, computed using Singular Value Decomposition (SVD) of a representative ground …


Consequences Of Spatial Heterogeneity For Turbulent Wake Development, Ryan Scott May 2024

Consequences Of Spatial Heterogeneity For Turbulent Wake Development, Ryan Scott

Dissertations and Theses

Spatial heterogeneity is an fundamental property of natural systems. In fluid dynamics subtle variations in fluid motion give rise to chaotic turbulent flows. When a fluid passes an object it retains an imprint of the object as a momentum deficit known as a wake. The resulting spatial structure of the wake is intrinsically linked to the object responsible for its creation. The coupling between geometric complexity in wake producing entities and turbulent wake evolution is considered in terms of spatial heterogeneity from individual wakes through turbulent canopy flows. First a novel Lacunarity-based method is developed for quantifying spatial heterogeneity in …


Electrochemical Nitrate Reduction To Ammonia On Cu Based Nanoparticles Using Quantum Mechanical Simulations, Kathan Bhavin Shukla May 2024

Electrochemical Nitrate Reduction To Ammonia On Cu Based Nanoparticles Using Quantum Mechanical Simulations, Kathan Bhavin Shukla

Theses

Nitrate reduction to ammonia (NRA) is critical for environmental remediation and energy conservation, as it can remove harmful nitrate (NO3-) from water sources while producing usable ammonia (NH3). Cu represents one of the most promising non-noble-metal NRA electrocatalysts. However, the intrinsic catalytic activity of Cu facets and their influence under different pH conditions remain unclear, particularly in the presence of ions commonly found in wastewater such as Cl-, Na+, Mg2+, and Ca2+. Using density functional theory (DFT) calculations, we evaluated the nitrate reduction to ammonia (NRA) pathways …


Neural Operator For Accelerating Coronal Magnetic Field Computations In Bifrost Mhd Model, Yutao Du May 2024

Neural Operator For Accelerating Coronal Magnetic Field Computations In Bifrost Mhd Model, Yutao Du

Theses

The application of the Tensorized Fourier Neural Operator (TFNO) to significantly enhance the computational efficiency of coronal magnetic field calculations within the Bifrost Magnetohydrodynamics (MHD) model is introduced in this study. Leveraging simulated data from the European Sunrise Science Data Center, the TFNO? an extension of the Fourier Neural Operator (FNO) that incorporates tensor decomposition for improved handling of high-dimensional data?is employed to solve time-varying partial differential equations (PDEs) over a 3D domain. The performance of the TFNO is compared with traditional machine learning methods, including Vision Transformer and CNN-RNN (encoder-decoder) architectures, to demonstrate its accuracy, computational efficiency, and scalability. …


Marking Estimation In Petri Nets Using Dynamic Mode Decomposition, Aditya Kale May 2024

Marking Estimation In Petri Nets Using Dynamic Mode Decomposition, Aditya Kale

Theses

Petri Nets (PNs) are a well-established framework for modeling and analyzing complex systems with interacting, concurrent processes. This thesis extends traditional Petri Net methodologies by integrating Dynamic Mode Decomposition (DMD), a technique originally developed for fluid dynamics, to analyze Continuous Petri Nets (CPNs). By applying DMD to CPN marking evolution, this research constructs a reduced-order model that captures its dynamics through dynamic modes and eigenvalues, enabling prediction of future markings without detailed knowledge of transition firings or underlying deterministic models. The principal contribution of this research is extending the kit of tools available for analysis of CPN dynamics, providing insights …


Targeted Drug Delivery: Investigating Protein Corona Behavior, Atharva Markale May 2024

Targeted Drug Delivery: Investigating Protein Corona Behavior, Atharva Markale

Theses

Due to high specificity and less toxicity, nanoparticles have become promising for targeted drug delivery against cancer, although they face challenges when they enter the bloodstream, making their behavior unpredictable. The deposition of proteins on nanoparticles, the protein corona, changes their biosignature, affecting their circulation, drug release potency, targeting ability, and immunogenicity. The continuous exchange of protein layers on a nanoscale is complex to analyze.

Nanoparticle tracking analysis (NTA) is a method to characterize nanoparticles in blood plasma by combining principles of light scattering microscopy and Brownian motion. In this work, time-dependent experiments with plasma were conducted to analyze the …


Methodology For Developing Biodegradable Polymer Blends And Composites For Agriculture, Fangzhong Xing May 2024

Methodology For Developing Biodegradable Polymer Blends And Composites For Agriculture, Fangzhong Xing

Theses

The use of polyethylene (PE) films to improve soil conditions and to increase crop yield has produced microplastics that are harmful to our ecosystem. The overall objective of this thesis is to develop an effective biodegradable polymer/composite to replace PE, and hence, to reduce microplastic pollution. The focus of this research is to develop a systematic protocol for assessing the suitability of the biodegradable films based on industry standards in agriculture. For this purpose, a range of biodegradable polymer blends are prepared using polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT) with varying PLA to PBAT ratios. Solvent casting combined with …


Modeling And Forecasting Cyanobacterial Harmful Algal Blooms (Cyanohabs) In Lake Pontchartrain, Shekhar Mahat May 2024

Modeling And Forecasting Cyanobacterial Harmful Algal Blooms (Cyanohabs) In Lake Pontchartrain, Shekhar Mahat

LSU Master's Theses

Harmful algal blooms (HABs) frequently occur in coastal waters worldwide, adversely affecting economies, human health, aquatic ecosystems, and recreational activities. Lake Pontchartrain, an oligohaline estuary, experienced frequent HABs from 2018 to 2023. While NOAA’s NCCOS and USEPA’s CyAN currently monitor cyanobacteria harmful algal blooms (CyanoHABs) in coastal, freshwater, and riverine systems, there is a notable lack of systems monitoring phycocyanin concentrations in the lake. This thesis utilizes satellite remote sensing environmental stressors to model and predict CyanoHABs in Lake Pontchartrain using machine learning techniques. A key focus of this study is assessing the forecasting capabilities of the random forest method …


Protectnic - Smartnic Ransomware Detection, Arnav Choudhury, Eason Liu, Anson Xu May 2024

Protectnic - Smartnic Ransomware Detection, Arnav Choudhury, Eason Liu, Anson Xu

Computer Science and Engineering Senior Theses

Ransomware, a form of malware that restricts access to data until a ransom is paid, accounts for 20% of all cyber crimes. Although companies and organizations often require their personnel to take training for awareness of such bad actors, social engineering is constantly evolving and ransomware slips through the cracks every year. In this paper, we suggest a system that would help detect ransomware using a Smart Network Interface Card (SmartNIC) which runs machine learning algorithms to detect ransomware before it enters the system. This relieves computers in the network of the burden of detecting malware, freeing CPU capacity to …


Design And Implementation Of Non-Isolated High Gain Dc-Dc Converter For Photovoltaic Application, Rajesh R May 2024

Design And Implementation Of Non-Isolated High Gain Dc-Dc Converter For Photovoltaic Application, Rajesh R

Theses and Dissertations

Fossil fuel-based power plants emit 25% of greenhouse gases and 40% of carbon emissions globally. Therefore, several countries focus on deploying RES-based electricity production (such as solar and wind). As per the International Energy Agency report, solar PV might be the lowest-cost option for generating electricity in the future. Solar energy is highly emission-free, but it is still a key challenge in procuring the maximum amount of energy from solar PV due to its non–linear characteristics. Therefore, a DC-DC converter must integrate with solar PV to increase the output voltage level. Many existing topologies exist in the literature, but the …


Connection-Saving Gate Assignment: A Computational Approach, Rob Mailley May 2024

Connection-Saving Gate Assignment: A Computational Approach, Rob Mailley

Computer Science Senior Theses

The growth of the commercial aviation industry has yielded many interesting problems in the field of Operations Research, many of which are now able to be solved as both technology and mathematical optimization improve. A particularly interesting problem in airport operations re- search is the Aircraft Gate Assignment Problem (AGAP), which seeks to create a feasible match- ing between planes and flights at an airport. This problem is well-suited to modeling with Integer Programming, and has attracted research since the 1970s. Researchers of the AGAP have considered many different objectives, ranging from airline-focused objectives to more passenger-focused objective functions. In …


Revealing Long Vehicle Dynamics: A Comprehensive Journey From Visualization Tools For Heavy Vehicles To Conversion Factors And Public Transit Performance Analysis, Eren Yuksel May 2024

Revealing Long Vehicle Dynamics: A Comprehensive Journey From Visualization Tools For Heavy Vehicles To Conversion Factors And Public Transit Performance Analysis, Eren Yuksel

USF Tampa Graduate Theses and Dissertations

Over the past few decades, there has been an increasing fascination with Intelligent Transportation Systems (ITS) and Connected and Autonomous Vehicle (CAV) technology, particularly in the realm of data collection and traffic management. Thanks to the possibilities unlocked by ITS and CAV technology, traffic data collection now serves a diverse array of safety and mobility applications, delivering real-time or near-real-time information for both road users and transportation professionals.

The integration of ITS and CAV technology is crucial for the creation of safer, more reliable, and sustainable transportation environments. As traffic-related data collection, analysis, and visualization form essential components of this …


Design Of Multi-Objective Optimization Algorithms For Vlsi Floor Planning, Srinivasan B May 2024

Design Of Multi-Objective Optimization Algorithms For Vlsi Floor Planning, Srinivasan B

Theses and Dissertations

VLSI floorplanning is a key design step that determines the optimal placement of circuit modules to minimize chip area, wire length, and heat generation. Existing swarm intelligence–based metaheuristics improve area and wire length but often ignore thermal effects.

To address this, the Multi-Objective Firefly Optimization–based Floorplanning (MOFO-FP) technique is introduced, using a Heat-Aware Firefly Optimization (HAFO) algorithm that minimizes heat, space, and wire length under fixed outline constraints. Each firefly represents a floorplan, with brightness indicating solution quality; dimmer fireflies move toward brighter ones to find optimal placements.

A second method, the Hybridized Multicriteria Ant Colony and …


Digitally Beamformed 2d Scanning Phased Array Radar For Networked Unmanned Air Vehicle Detection And Tracking, Carson Reed Brown May 2024

Digitally Beamformed 2d Scanning Phased Array Radar For Networked Unmanned Air Vehicle Detection And Tracking, Carson Reed Brown

Theses and Dissertations

Radar systems vary significantly in size, weight, power, and cost (SWaP-C) characteristics with many high SWaP-C models being inaccessible to consumers. Recognizing this, we have engineered an effective but low SWaP-C networked radar system tailored for detecting and tracking unmanned air vehicle (UAV) traffic. Using field-programmable gate arrays (FPGAs), and custom-designed printed circuit boards (PCBs), our system achieves remarkable efficiency without compromising performance. We use patch antennas for our transmitter and in our 4x4 receiver array. With our low SWaP-C system we have successfully concluded outdoor range testing, detecting corner reflector targets at a remarkable 10dB above our noise floor …


Mobile Robot Path Planning Optimization Problem Using Multi- Objective Genetic Algorithm, Suresh Ks May 2024

Mobile Robot Path Planning Optimization Problem Using Multi- Objective Genetic Algorithm, Suresh Ks

Theses and Dissertations

Mobile Robot Path Planning problem (MRPPP) is the most prominent research area employed in different real-time environments. The research domain of robotics offers abundant opportunities for researchers in various engineering fields with different dimensions. The automation of physical movements of the robots with intelligence to make dynamic decisions for interacting with the environment opens up a lot of challenges to the research community.

A variety of approaches are employed to solve the Mobile Robot Path Planning Problem (MRPP), which is to derive a feasible collision-free path to reach the destination from the given starting point by avoiding obstacles. The solution …


Synthesis Of Geopolymer Using Coal Fly Ash And Corn Stover, Anu Paneru May 2024

Synthesis Of Geopolymer Using Coal Fly Ash And Corn Stover, Anu Paneru

Master's Theses

The development of each nation is dependent on its infrastructure, and nations are competing with others in infrastructure, especially in the construction of roadways, since they play a vital role in the economic and social development of the nation. The conventional materials used for road construction are cement and asphalt, which pose significant environmental challenges. This thesis explores the potential of fly ash (FA) and corn stover (CS) in synthesizing geopolymer, as an alternative material for the construction of roads. The study examines the impact of FA and CS percentages and the particle sizes of CS on the compressive strength, …


Comparing Proliferation Rates And Collagen Production Of Cells Treated With Cuhars, Katie Elizabeth Mckenzie May 2024

Comparing Proliferation Rates And Collagen Production Of Cells Treated With Cuhars, Katie Elizabeth Mckenzie

Master's Theses

Cartilage is the padding in joints that protects the bones and aids in motion. Problems with the cartilage in the knee can be caused by mechanical damage or diseases like osteoarthritis. Chondrocytes make cartilage. The objective of this study is to determine the doubling time of chondrocytes per passage. I also want to determine the base amount of collagen-II created by chondrocytes as they age. I also want to determine how long it takes CuHARS to break down in different cell medias. Chondrocytes, human dermal fibroblasts, and CRL 2303 cells were grown and cultured for over a year. During that …


Impact Of Student Beliefs And Self-Efficacy On Performance In Higher Education Stem Courses, Lauren Nicole Fogg May 2024

Impact Of Student Beliefs And Self-Efficacy On Performance In Higher Education Stem Courses, Lauren Nicole Fogg

Doctoral Dissertations

In engineering education, students often face feelings of inadequacy, leading to academic struggles and potential dropout. This dissertation investigates the impact of interactive course materials on students' confidence and self-efficacy in problem-solving, focusing on an Engineering Materials class at Louisiana Tech University. Over four quarters, involving seven sections and 218 students, a 13-question Likert scale survey was administered repeatedly, alongside demographic data and textbook usage surveys. The study aims to compare students’ attitudes and beliefs when not using a textbook versus when using an interactive web-native book. Hypotheses suggest that the interactive book will enhance problem-solving beliefs, confidence, and grades. …


Phase Interface Dynamics And Heat Transfer Mechanisms In Evaporating Droplet And Pool Boiling Processes, Md Tanbin Hasan Mondal May 2024

Phase Interface Dynamics And Heat Transfer Mechanisms In Evaporating Droplet And Pool Boiling Processes, Md Tanbin Hasan Mondal

Doctoral Dissertations

Despite the significant importance and widespread use of phase-change cooling techniques, there are still fundamental questions about the microscopic processes that govern the heat transfer mechanisms. In order to gain a better understanding of the underlying physics involved, it is essential to have information at the microscale regarding the surface temperature distribution with time as well as the location and speed of the moving contact line (MCL). A comprehensive understanding of heat transfer mechanisms and phase-interface behavior during phase-change cooling is crucial for improving heat transfer models, optimizing surface engineering, and maximizing overall effectiveness. Firstly, this dissertation presents a capacitance-based …


Development Of Quantum True Random Number Generators And Implementation On Ibm Cloud Lab, Vaishnavi K May 2024

Development Of Quantum True Random Number Generators And Implementation On Ibm Cloud Lab, Vaishnavi K

Theses and Dissertations

Random numbers are the lifeline of any cryptographic operation in modern computing. Quantum mechanics has the intrinsic ability to generate truly random numbers, making it an ideal alternative for scientific applications that require high-quality randomness. Quantum True Random Number Generators (QTRNGs) can yield real random data to replace random-looking periodic sequences. To construct such a random number generator, this work uses the IBM Q Experience platform called Qiskit.

This research focuses on the development and analysis of quantum-based TRNGs along with their prime characteristics. Qubits and quantum gates are the predominant sources of true randomness on quantum platforms. These inherent …


Combinatorial Studies Of Noble Metal Catalysts For Carbon Utilization, Natalie Leong Page May 2024

Combinatorial Studies Of Noble Metal Catalysts For Carbon Utilization, Natalie Leong Page

Theses and Dissertations

Electrocatalysts demonstrate significant promise for sustainable processes like carbon capture and generating recycled carbon fuels which are needed to achieve net zero carbon emissions. However, the commercialization of these processes is limited by several factors, one of which is the high cost of catalysts. The discovery and development of cheaper alternatives has been difficult due to constraints in experimental methodologies, scalability limitations, and a lack of understanding of reaction mechanisms. Within this dissertation is the development of a novel scanning electrochemical system and its implementation for high-throughput data generation from combinatorially sputtered material libraries. Combinatorial Pd-Au alloys were investigated for …


Design And Test Of Asynchronous Systems Using The Link And Joint Model, Ebelechukwu Esimai May 2024

Design And Test Of Asynchronous Systems Using The Link And Joint Model, Ebelechukwu Esimai

Dissertations and Theses

Asynchronous circuits offer numerous advantages, including low energy consumption and good composability and scalability. However, they remain meagerly adopted in the mainstream semiconductor industry. One reason is the limited number of design tools available to help designers navigate design complexity, particularly the myriad of asynchronous implementation styles.

This dissertation focuses on managing the myriad of asynchronous implementation styles by utilizing a circuit-neutral model, called Links and Joints, and embedding this Link-Joint approach into a design flow. Although years of past work have already laid the groundwork, the work in this dissertation identifies and addresses key missing pieces.

First, the …


Design And Development Of Contactless Capacitive Coupled Electrodes For Cardiovascular Signal Acquisition, Ramya Lakshmi Vs May 2024

Design And Development Of Contactless Capacitive Coupled Electrodes For Cardiovascular Signal Acquisition, Ramya Lakshmi Vs

Theses and Dissertations

In biosignal acquisition and physiological monitoring, developing advanced electrode technologies is crucial in enhancing signal quality, minimizing interference, and improving overall reliability. One such innovative approach is the utilization of capacitive-coupled electrodes, a cutting-edge solution that addresses some of the challenges associated with traditional electrodes in biosignal recording.

Capacitive-based sensors have become prominent in physiological signal measurement over the past decade. The electric field from the external affects both the human body and the electrode. The primary aim while designing the capacitive electrode is to maximize the signal-to-noise ratio. Hence, we introduce shielding and guarding techniques to improve the signal-to-noise …