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University of Central Florida

2023

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Articles 91 - 102 of 102

Full-Text Articles in Engineering

Exploring A Lab-Scale Cascade Upflow Bioreactor System For Nitrogen Removal Via Biosorption Activated Media, Alejandra Robles Lecompte Jan 2023

Exploring A Lab-Scale Cascade Upflow Bioreactor System For Nitrogen Removal Via Biosorption Activated Media, Alejandra Robles Lecompte

Graduate Thesis and Dissertation 2023-2024

Many Best Management Practices (BMPs) have been developed to reduce excessive nutrients in stormwater runoff and mitigate harmful algal blooms in downstream receiving water bodies. This study demonstrates a new BMP by comparing two green sorption media (i.e., specialty adsorbents) for nutrient removal in cascade upflow biofiltration systems operated in parallel. The proposed filtration technology can control hydraulic gradients, prevent clogging and settlements, and increase hydraulic loading while removing more nutrients in an integrated physicochemical and microbiological treatment process. The two green sorption media being tested in this study include zero-valent-iron and perlite-based green sorption media (ZIPGEM) and biochar, iron, …

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Coalition Formation And Beamsteering Optimization For Directional Software-Defined Radios, Sayanta Seth Jan 2023

Coalition Formation And Beamsteering Optimization For Directional Software-Defined Radios, Sayanta Seth

Graduate Thesis and Dissertation 2023-2024

Dynamic Spectrum Access (DSA), also known as Dynamic Spectrum Management, is the method of utilizing a set of spectrum techniques in real time to provide the ability to share wireless channels between Primary (or licensed) users (PUs) and Secondary (or unlicensed) users (SUs). The system is so designed that under normal circumstances, the PUs always get priority, but DSA enables the SUs to use the licensed bands as long as they do not create any interference on the PUs. Hence, the goal of utilizing the spectrum more efficiently can be achieved. Though DSA has been researched extensively as a new …

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Understanding Workforce Agility At Nasa Kennedy Space Center, Ledlyne H. Vazquez Jan 2023

Understanding Workforce Agility At Nasa Kennedy Space Center, Ledlyne H. Vazquez

Graduate Thesis and Dissertation 2023-2024

This study aims to define workforce agility via a literature review and a conducted research survey of the Kennedy Space Center (KSC) Engineering workforce. The survey results will help us determine the workforce agility of the KSC engineering team and understand what has allowed them to transition from the Space Shuttle Program to the new Exploration Ground System (EGS) program. Structural Equation Modeling was used to develop a model of relationships to test the hypotheses. The results show that organizational practices and psychological empowerment significantly support workforce agility. The implications of this study for understanding the characteristics of workforce agility …

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Thermal Management Strategies For Hypersonic Flight: Supercritical Co2 Jet Impingement Cooling Investigation For Leading Edge, Manoj Prabakar Sargunaraj Jan 2023

Thermal Management Strategies For Hypersonic Flight: Supercritical Co2 Jet Impingement Cooling Investigation For Leading Edge, Manoj Prabakar Sargunaraj

Graduate Thesis and Dissertation 2023-2024

This study addresses the critical need for effective thermal management in hypersonic vehicles facing intense heat at their leading edge due to high enthalpy flow. The objective is to propose an active impingement cooling system that ensures the structural stability and performance of these vehicles. This dissertation presents an in-depth exploration of the numerical simulations conducted on the hypersonic leading edge, focusing on a 3mm radius with active cooling utilizing supercritical carbon dioxide (sCO2) as the coolant. The research incorporates conjugate simulations that merge external hypersonic flow and sCO2 active cooling. Utilizing a thermodynamic non-equilibrium two-temperature model and various chemical …

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Safety Considerations For Setting Variable Speed Limits On Freeways, Md Tarek Hasan Jan 2023

Safety Considerations For Setting Variable Speed Limits On Freeways, Md Tarek Hasan

Graduate Thesis and Dissertation 2023-2024

This thesis focuses on evaluating the appropriate speed at which vehicles should travel under different traffic conditions on freeways and its impact on crash frequency. The common belief is that the lower speed results in fewer crashes as reduced speed provides drivers with more time to react effectively and avoid collisions. However, this perspective overlooks the interplay among traffic speed, average spacing between consecutive vehicles, and the distance available for stopping a vehicle. Hence, we propose a safety parameter termed ‘Safety Correlate' (SCORE), which is defined as the proportion of average spacing relative to the stopping distance. To determine the …

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Structural Transformations In Photo-Thermo-Refractive Glass For Hologram Recording, Roberto Alejandro Alvarez Aguirre Jan 2023

Structural Transformations In Photo-Thermo-Refractive Glass For Hologram Recording, Roberto Alejandro Alvarez Aguirre

Electronic Theses and Dissertations, 2020-

This dissertation focuses on the structural transformations in photo-thermo-refractive (PTR) glass that enable recording phase holograms for efficient transformation of optical beams and high resolution spectroscopy. PTR glass is a multicomponent silicate matrix doped with Ce, Ag, Sn and Sb. It is a holographic phase medium with the ability of permanent refractive index change after UV exposure and thermal development above 500°C due to the precipitation of a NaF crystalline phase. Electronic processes are studied by analyzing the structure of absorption and luminescence bands of PTR glass matrix and its dopants. We analyze the structural transformations in PTR glass from …

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Investigation Of Endothelial Mechanics On Primary Cell Functions: Endothelium Permeability And Wound Healing, Sean Beverung Jan 2023

Investigation Of Endothelial Mechanics On Primary Cell Functions: Endothelium Permeability And Wound Healing, Sean Beverung

Electronic Theses and Dissertations, 2020-

The endothelium composes the inner lining of blood vessels, the heart, and lymphatic vessels. Within the cardiovascular system, it is an extremely important structure, aiding in the regulation of blood pressure with the vascular tone, recruiting immune response, regulating the transfer of material in and out of the bloodstream, and the creation of new blood vessels through angiogenesis. The endothelium is composed entirely of endothelial cells. These cells lay in a flat squamous formation and are in direct contact with blood and aid in the regulation and transfer of material in and out of the bloodstream via active and passive …

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Design Considerations And Imaging Setup For Liquid Fuel Droplet Detonation Wave Experiments, Nicolas Berube Jan 2023

Design Considerations And Imaging Setup For Liquid Fuel Droplet Detonation Wave Experiments, Nicolas Berube

Electronic Theses and Dissertations, 2020-

Initial results, design considerations, and experimental validation of a new detonation tube are presented to further improve detonation wave interaction research. The new structure consists of four independent portions: the deflagration to detonation initiation section, transition expansion section, operating test section, and dump section. The initiation, transition, and test sections are designed to operate within a temperature limit of 150°C and a maximum detonation pressure of 100 bar. The test section is comprised of interchangeable 155 cm stainless steel 316 plates assembled to create a 10x10 cm square hollow structure, sealed with longitudinal O-rings between plates and lateral O-rings between …

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High-Efficieny Ultrafast Mid-Infrared Source For Strong Field Science, Fangjie Zhou Jan 2023

High-Efficieny Ultrafast Mid-Infrared Source For Strong Field Science, Fangjie Zhou

Electronic Theses and Dissertations, 2020-

The potential of high-energy sources within the mid-infrared region (3-8 μm) has garnered significant attention for diverse research and industrial applications. Millijoule pulses extending beyond 3 μm can facilitate the production of x-rays with photon energies in the keV range through high harmonic generation (HHG). These high-energy x-ray pulses enable the characterization of electron dynamics within molecules and condensed matter materials. Additionally, the atmospheric transmission window between 3-5 μm allows lasers within this spectral range to deliver energy efficiently to distant targets via optical filaments without divergence, highlighting promising prospects for defense applications. In contrast to laser amplifiers, which are …

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Active Photonic Integrated Devices And Circuits On Thin-Film Lithium Niobate Platform, Ehsan Ordouie Jan 2023

Active Photonic Integrated Devices And Circuits On Thin-Film Lithium Niobate Platform, Ehsan Ordouie

Electronic Theses and Dissertations, 2020-

This thesis delves into innovative active photonic integrated devices and circuits on the thin-film lithium niobate (TFLN) platform, focusing on their applications and potential future advancements. We introduce a new family of electrooptic modulators (EOMs), the Four-Phase Electrooptic Modulators (FEOMs), which are fabricated using the TFLN platform. These devices effectively mitigate bandwidth and dynamic-range constraints in optical communication systems by reducing dispersion penalties and common-mode noises. Their functionality is demonstrated in a photonic time-stretch system. A dual-polarization variant further exemplifies the mitigation of both dispersion penalties and common-mode noises in long-haul communication links, marking significant strides towards the practical implementation …

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Optimizing Biomechanical Models: Estimation Of Muscle Tendon Parameters And Ankle Foot Orthosis Stiffness, Sepehr Ramezani Jan 2023

Optimizing Biomechanical Models: Estimation Of Muscle Tendon Parameters And Ankle Foot Orthosis Stiffness, Sepehr Ramezani

Electronic Theses and Dissertations, 2020-

The complexity of the human musculoskeletal system presents challenges in accurately identifying its characteristics, particularly due to the presence of redundant actuators on a single joint. Non-invasive measures are necessary to overcome these challenges. Optimization algorithms have emerged as a crucial tool to advance subject-specific musculoskeletal modeling allows a more realistic representation of biomechanical behaviors, enhancing our understanding of human movement and enabling better clinical decision-making. Furthermore, optimization algorithms play a vital role in customizing rehabilitation and assistive devices, such as orthoses and prostheses. The current ankle-foot orthosis (AFO) stiffness measurement methods require bulky, complex designs, and often permanent modification …

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Design And Simulation Analysis Of A Bipv (Building Integrated With Pv) Air-Duct System For Residential High-Performance Development, Arash Zarmehr Jan 2023

Design And Simulation Analysis Of A Bipv (Building Integrated With Pv) Air-Duct System For Residential High-Performance Development, Arash Zarmehr

Electronic Theses and Dissertations, 2020-

A growing number of buildings are integrating building-integrated photovoltaics (BIPV) devices to increase energy efficiency and reduce energy costs. A building's heating and cooling loads are impacted by the thermal resistance of the air duct BIPV because of the change in thermal resistance. Therefore, augmenting the efficiency of (BIPV) devices will benefit many building architectures and mechanical engineering applications. This work introduces a low-cost and low- maintenance air duct system design augmenting BIPV systems. This novel approach increases airflow velocity and decreases air temperature for BIPV, resulting in improved performance for the PV system electricity output, increased PV lifespan due …

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