Engineering Commons^™

Radiometric Correction Of Multispectral Cameras Using Photosensor Irradiance For Agronomy Applications, Nicholas S. Mitchell

Electronic Thesis and Dissertation Repository

Cloud coverage has a significant impact on the reflectance maps generated by multispectral cameras mounted on UAV's in small farm settings. The current approach is to calibrate the camera once before every flight and use the radiometric calibration map for the entire flight. In this work we have designed and built a downwelling and upwelling photosensor to work in sync with our custom multispectral camera. A dual reflectance panel implementation for the time dependent radiometric calibration of the multispectral camera is completed. The solar spectral irradiance curve is approximated using the current measurements from the downwelling photosensor and the ground …

Antenna Radiation Element Designs For 5g Applications, Zhijun Gui

Electrical Engineering Undergraduate Honors Theses

This thesis introduced the advantage of the fifth-generation network and gave examples to the three major classes of applications categorized by International Telecommunication Union-Radiocommunication Sector. In this work, a patch antenna and a board-band bow-tie antenna with microelectromechanical switch design were modified to meet 5G communication purposes. The revised patch antenna produced a minimum S11 of -57.92dB, a resonant frequency at the 28GHz, and bandwidth of 4.55GHz. The modified design meets the requirements for wireless communication purposes. During the duplication process of the board-band bow-tie antenna design, multiple discrepancies were found, and the proposed results were not able to achieve. …

Sparse Bases And Bayesian Inference Of Electromagnetic Scattering, John Lee

Theses and Dissertations

Many approaches in CEM rely on the decomposition of complex radiation and scattering behavior with a set of basis vectors. Accurate estimation of the quantities of interest can be synthesized through a weighted sum of these vectors. In addition to basis decompositions, sparse signal processing techniques developed in the CS community can be leveraged when only a small subset of the basis vectors are required to sufficiently represent the quantity of interest. We investigate several concepts in which novel bases are applied to common electromagnetic problems and leverage the sparsity property to improve performance and/or reduce computational burden. The first …

Electromagnetic Interference Estimation Via Conditional Neural Processing, Edgar E. Gomez

Theses and Dissertations

The goal of this thesis is to determine the efficacy of employing Machine Learning (ML) to solve Joint Urgent Operational Need (JUON) CC-0575, which aims to develop a Common Operating Picture (COP) of the Global Positioning System (GPS) Electromagnetic Interference (EMI) environment. With the growing popularity of Artificial Neural Networks (ANNs), ML solutions are quickly gaining traction in businesses, academia and government. This in turn allows for problem solutions that were previously inconceivable using the classical programming paradigm. This thesis proposes a method to develop a COP of the battlefield via ANN ingestion of multiple-source signals and sensors. We conduct …

Development And Characterization Of Metal Contacts For Graded Composition Ingan Solar Cells, Reem E. Alhelais

Graduate Theses and Dissertations

There is an increasing demand for high-power electronic components and optoelectronic devices with low-loss and high efficiency. III-nitride semiconductor materials have demonstrated great potential for high-power, high-frequency, and high-temperature applications because of their remarkable and wide-ranging electronic and physical properties. These material systems, including alloys of AlN, GaN, and InN, are currently being explored for their potential to develop efficient photovoltaic cells. They can potentially achieve higher efficiency because of their very high direct wide band edge, absorption coefficients, and resistance to defects. The compositionally graded Group III-nitride alloy allows access to a large range of energies by varying the …

Fourier Transform Infrared Spectroscopy For The Measurement Of Gesn/(Si)Gesn, Solomon Opeyemi Ojo

Graduate Theses and Dissertations

Photoluminescence (PL) and Electroluminescence (EL) characterization techniques are important tools for studying the optical and electrical properties of (Si)GeSn. Light emission from these PL and EL measurements provides relevant information on material quality, bandgap energy, current density, and device efficiency. Prior to this work, the in-house PL set-up of this lab which involves the use of a commercially-obtained dispersive spectrometer was used for characterizing both GeSn thin film and fabricated devices, but these measurements were limited by issues bordering on low spectral resolution, spectral artifacts, and poor signal-to-noise ratio (SNR) thereby resulting in the possible loss of vital information and …

Multiphoton Microscopy And Deep Learning Neural Networks For The Automated Quantification Of In Vivo, Label-Free Optical Biomarkers Of Skin Wound Healing, Jake D. Jones

Graduate Theses and Dissertations

Non-healing ulcerative wounds that occur frequently in diseases such as diabetes are challenging to diagnose and treat due to numerous possible etiologies and the variable efficacy of wound care products. With advanced age, skin wound healing is often delayed, leaving elderly patients at high risk for developing these chronic injuries. As it is challenging to discriminate age-related delays from disease-related chronicity, there is a critical need to develop new quantitative biomarkers that are sensitive to wound status. Multiphoton microscopy (MPM) techniques are well-suited for 3D imaging of epithelia and are capable of non-invasively detecting metabolic cofactors (NADH and FAD) without …

Simulation Of An Sp8t 18 Ghz Rf Switch Using Smt Pin Diodes, Andre De Souza Vigano

Master's Theses

Radio frequency (RF) and microwave switches are widely used in several different applications including radar, measurement systems, telecommunications, and other areas. An RF switch can control a radar’s transmit vs. receive mode, select the operating band, or direct an RF signal to different paths. In this study, a single pole eight throw (SP8T) switch using only Surface Mount (SMT) components is designed and simulated in Keysight’s Advanced Design System (ADS). Single pole eight throw is defined as one input and eight possible outputs. A star network configuration with series-shunt PIN diode switches is used to create the 8-way RF switch. …

Detailed Modeling Of The Flash Hydrolysis Of Algae For Biofuel-Production In Comsol Multiphysics, Noah Joseph Legrand

Mechanical & Aerospace Engineering Theses & Dissertations

Algae-derived biofuels are being commercialized as an important renewable energy source. Like any new technology, conversion improvements are desired, including reductions in process complexity and better utilization of the entire microalgae feedstock. The Old Dominion Biomass Laboratory has focused on flash hydrolysis for algae biofuel production. That process involves rapidly heating algae and water mixed as a slurry to a subcritical state. Results from small-scale bench tests are promising, but process scale up is a challenge. Currently there exists a pilot laboratory scale system utilizing induction heating in order to reach controlled reaction temperatures with a reaction duration of 10 …

On-Chip Nonreciprocal Components For Full-Duplex Communications And Gaussian Regulated Gate Driver For Electromagnetic Interference Reduction, Chang Yang

Electrical Engineering Theses and Dissertations

This dissertation is comprised of two unrelated design endeavors. The first one is about two CMOS nonreciprocal components: 1) an isolator and 2) a circulator. To make the components compact enough for the next generation communication systems with wide bandwidth, both components operate at 100 GHz band for full-duplex transceivers for ultra-high-data-rate millimeter-wave wireless communication. The proposed nonreciprocal structures are based on a time-domain modulation by signals at around 1/6 of the RF frequencies and spatial duplexing over the RF signal paths, demonstrating over 45 dB isolation in a bandwidth of 1.5 GHz over the tuning range of 85-110 GHz. …

Design And Analysis Of Fully-Electronic Magnet-Free Non-Reciprocal Metamaterial, Swadesh Poddar

Theses and Dissertations

Reciprocity is a fundamental and very important characteristics of the vast majority of electronic devices, and requires that signals travel in both forward and reverse directions in the same manner. Similarly, electromagnetic non-reciprocity or one way wave propagation, implies that the field created by a source at an observation point is not the same when source and observation points are interchanged. Non-reciprocal devices such as isolators, circulators, phase shifters, polarizers,

switches, tunable resonators, tunable filters, and gyrators enable new applications from radio frequencies to optical frequencies. However, non-reciprocity has been implemented in the past using ferrites in the presence of …

Validation Of Nanosecond Pulse Cancellation Using A Quadrupole Exposure System, Hollie A. Ryan

Biomedical Engineering Theses & Dissertations

Nanosecond pulsed electric fields (nsPEFs) offer a plethora of opportunities for developing integrative technologies as complements or alternatives to traditional medicine. Studies on the biological effects of nsPEFs in vitro and in vivo have revealed unique characteristics that suggest the potential for minimized risk of complications in patients, such as the ability of unipolar nsEPs to create permanent or transient pores in cell membranes that trigger localized lethal or non-lethal outcomes without consequential heating. A more recent finding was that such responses could be diminished by applying a bipolar pulse instead, a phenomenon dubbed bipolar cancellation, paving the way …

Advanced Parallel Algorithms In Computational Electromagnetics, Shu Wang

Electrical and Computer Engineering ETDs

The rapid development of high performance computing has pushed the computational electromagnetic(CEM) towards high accuracy, high fidelity and extreme computational scales. There is a great need for existing CEM solvers to have enhanced parallelism and scaling capability. The purpose of this dissertation is to investigate advanced parallel algorithms for both frequency and time domain solvers.

In frequency domain, this work first develop the underpinnings of parallel preconditioning technique and high-order transmission condition in the context of multi-solver scheme. The result is a computing resource-aware and implementation wise compact solver. Then this work targeted at developing efficient algorithms for cases where …

Conducted Emi Mitigation In Power Converters Using Active Emi Filters, Balaji Narayanasamy

Graduate Theses and Dissertations

Wide bandgap devices enable high power density power converters. Despite the advantages of increased switching frequency, the passive components are still a major bottleneck towards enabling high power density. Among the passive components in the converter, the passive EMI filters are unavoidable to ensure compliance with conducted EMI standards. Active EMI filters help reduce the volume of the passive components and have been around for three decades now. Firstly, this work presents a summary of all the different active EMI filters based on the type of noise-sensing, noise-processing, the type of active circuits used and the type of control methods. …

Investigation Of The Structural, Electronic, And Thermoelectric Properties Of Mono- Chalcogenides, Aida Sheibani

Graduate Theses and Dissertations

The structural, electronic, and thermoelectric properties of GeTe are studied using density functional theory and Boltzmann transport equations. This material has a rhombohedral crystal structure in ambient temperature with a ferroelectric behavior due to lack of inversion symmetry. This study suggests that the presence of asymmetry in GeTe can lead to an improvement in the thermoelectric properties of this material. In addition, studies on introducing Group III, IV, and V dopants to GeSe show that while these impurities can improve the power factor and decrease the lattice thermal conductivity, they cannot enhance the figure of merit.

Development Of High-Density Propulsion System Technologies For Interplanetary Small Satellites And Cubesats, Morgan Andrew Roddy

Graduate Theses and Dissertations

The goal of this research was to support the development of a novel propulsion system for small satellites (<180 kg) and CubeSats. This was pursued by conducting a collection of studies that were designed to provide engineering data that would be critical in designing a functional prototype. The novel propulsion system was conceived by the author to provide best-in-class performance for the small satellite and CubeSat families of spacecraft. This context presents specific design requirements that the presented technology attempts to satisfy. The most critical among these is high density; the propellant was designed to be stored with high density and the thruster was designed to be as compact as possible. The propulsion system is composed of two primary elements, a propellant generator and a thruster. The propellant generator works by sublimating a solid crystal into vapor and then using this vapor to etch a dense metal. The resulting gaseous byproducts of this reaction are the propellant. This dissertation used xenon difluoride (XeF2) vapor to etch tungsten (W) which react to form xenon gas (Xe) and tungsten hexafluoride (WF6). This approach gave a theoretical propellant storage density 5.40 g/cm3; and 5.17 g/cm3 was demonstrated. The sublimation dynamics of the XeF2 were studied as a function of surface area and temperature and it was found to be suitable for the intended application due to its high effluence rate; that is, it sublimates fast enough to be useful. The sublimation rates are on the order of 10’s of µg/s. The etch rate of XeF2 on W was also studied and found to be suitably fast to provide useful amounts of reactants for use as a propellant, again on the order of 1’s of µg/s. The thruster is an electrostatic radio frequency (RF) ion thruster design and is manufactured with Low Temperature Co-Fired Ceramic (LTCC) materials system and manufacturing technology. Manufacturing samples of the thruster were built at the University of Arkansas in July 2015 and tested at NASA’s Marshall Space Flight Center in May 2018. Testing validated the viability of the LTCC thruster and provided valuable information on how to improve the thruster’s design.

Coffee Can Radar System, Dale Coker

Honors Theses

A Radio Detection and Ranging (“radar”) system detects a target and accurately determines its range and velocity using radio frequency (RF) waves. In the presence of a target, these RF waves are reflected, received, and processed. Until recently, radar systems have been too expensive to implement as undergraduate research projects, primarily because of the cost of the associated RF components. Recently, MIT has developed a low-cost radar system as part of an open-source course. Therefore, one objective of this project is to design and construct a radar system based on the MIT design. A further objective is to develop a …

Neutrino Detection Antenna, Samuel D. Keechler

Electrical Engineering

Neutrinos carry valuable information about deep space events that researchers can utilize to study the early universe. Since the first neutrino was detected in 1956, it is a relatively new physics research topic. A new state-of-the-art research facility, the Radio Neutrino Observatory in Greenland (RNO-G), was developed to detect Ultra-High Energy (UHE) neutrinos, ones with energy greater than 100 PeV (1015 electronvolts). For reference, this amount of energy lifts an apple 5 cm, or drives a neutrino, a particle 1034 times smaller by mass, near the speed of light [1]. UHE neutrino events typically occur less than five times a …

High Efficiency Rf Amplifier Design, Evan W. Johnson

Electrical Engineering

High efficiency RF power amplifiers are key to the operation of modern wireless systems. From reducing power consumption at base stations to increasing battery life in handsets, high efficiency amplifiers help system designers to meet key performance criteria for their customers. The advent of the Internet of Things and 5G will lead to mass proliferation of battery operated wireless devices, increasing demand for high efficiency systems. In this project, a high efficiency 4W narrowband PA operating at 1GHz is designed, built and tested for the IMS2020 high efficiency power amplifier (HEPA) design competition. Emphasis is placed on achieving maximum power-added …

The Characterization Of Effective Electromagnetic Fields On The Safety And Quality Of Low-Moisture Foods (Effs) - Prototype Device Development, Joe G. Sandoval

Electrical Engineering

Contamination of low-moisture foods including flour, wheat grain, baby formula, and more, have increasingly become a concern due to sanitizing challenges. While industrial food processors have long used RF heating to sanitize mass quantities, an equivalent consumer device is absent from the market today. The Characterization of Effective Electromagnetic Fields on the Safety and Quality of Low-Moisture Foods (EEFS) project is an interdisciplinary effort to develop an RF heating consumer device to sanitize low-moisture foods.

A prototype device was designed to sanitize low-moisture food items using RF heating acceptable for commercial or consumer applications.

Spectral 3d Reconstruction Based On Macroscopic Oct Imaging, Xingyu Zhou

Theses

Various optical technologies have been utilized to improve art conservation by art conservators, such as laser triangulation, stereophotogrammetry, structured light, laser scanner and time of flight sensors. These methods have been deployed to capture the 3D or surface topography information of sculptures and architectures. Optical coherence tomography (OCT) has introduced new imaging methods to study the surface features and subsurface structures of delicate cultural heritage objects. However, despite its higher spatial resolution, the field of view (FOV) of OCT severely limits the size of the scanning area and does not allow macroscopic examination. To solve this issue, we develop and …

Control And Locomotion Of Inertially And Magnetically Actuated Multi-Scale Robotic Systems, Ehab Al Khatib

Mechanical Engineering Research Theses and Dissertations

In this research, two actuation systems were introduced, inertial and magnetic actuation. In the inertial actuation, the robot used the transfer of momentum to navigate, and this momentum could be generated by spinning masses and wheels. Recent studies in our System Laboratory proved that a wide range of inertially actuated locomotion systems could be generated. This can be achieved by using a family tree approach, starting from a very simple system, and progressively evolving it to more complex ones. The motion diversity of these robots inspired us to extend their locomotion from a macro scale to millimeter and micro scales. …

Development And Test Of High Temperature Surface Acoustic Wave Gas Sensors, Armando E. Ayes Moncada

Electronic Theses and Dissertations

The demand for sensors in hostile environments, such as power plant environments, exhaust systems and high-temperature metallurgy environments, has risen over the past decades in a continuous attempt to increase process control, improve energy and process efficiency in production, reduce operational and maintenance costs, increase safety, and perform condition-based maintenance in equipment and structures operating in high-temperature, harsh-environment conditions. The increased reliability, improved performance, and development of new sensors and networks with a multitude of components, especially wireless networks, are the target for operation in harsh environments. Gas sensors, in particular hydrogen gas sensors, operating above 200°C are required in …

Design And Verification Of Search Coil Inductance For Pulse Induction Metal Detection, David Desrochers

Electrical Engineering Undergraduate Honors Theses

As violent attacks have increased at different venues such as schools, the need for affordable and effective metallic weapon detection has increased. Probing and scanning detection wands are the most common seen in use by guards. This project seeks to combine both probing and scanning coils into one pulse induction metal detector. The use of one drive circuit for both LC coil tank circuits further economizes the system. ANSYS Maxwell electromagnetic simulations are used to develop the geometries needed for sensitive metal detection. Analytical, simulation, and experimental methods are used to first verify the design flow for solenoid inductors. These …

Early Warning Solar Storm Prediction, Ian D. Lumsden, Marvin Joshi, Matthew Smalley, Aiden Rutter, Ben Klein

Chancellor’s Honors Program Projects

No abstract provided.

Advancing Compact Pulsed Power, Jon C. Pouncey

Electrical and Computer Engineering ETDs

The first two decades of the 21^st century have seen significant interest in expanding the application of pulsed power technology beyond its traditional use in physics and nuclear weapons research. Applications in the field of national defense, which present unique constraints on system size, have provided impetus to increase the exploration of compact pulsed power solutions. Innovations related to energy density, insulation, switching, and power conversion systems have been realized, bringing deployable compact pulsed power systems closer to realization than ever before. However, recent systems integration efforts have shown that work still remains to develop needed tools and technologies …

Development Of A Monolithic Implantable Neural Interface From Cubic Silicon Carbide And Evaluation Of Its Mri Compatibility, Mohammad Beygi

USF Tampa Graduate Theses and Dissertations

One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from device material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. In the first section of this dissertation, the fabrication and initial electrochemical characterization of a monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe is reported. …

Dynamic Micromechanical Fabry-Perot Cavity Sensors Fabricated By Multiphoton Absorption Onto Optical Fiber Tips, Jeremiah C. Williams

Theses and Dissertations

This research leveraged two-photon polymerization microfabrication to integrate dynamic mechanical components with Fabry-Perot resonators onto the ends of low-loss optical fibers to prototype 3 micro-optic devices. The first device featured a multi-positional mirror that enabled thin-film deposition onto cavities of any length with mirrors of significant curvature, for refractive index sensing. The second device combined an FP cavity with a spring body featuring easily scalable stiffness for pressure sensing. The third device presented a high-speed rotating micro-anemometer for measuring a wide range of gas flows. All devices represent a significant reduction in size and weight over commercially available devices.

Characterization And Sensitivity Analysis Of 6 Meter Cassegrain Antenna, James L. Harris

Theses and Dissertations

This paper will characterize a 6 meter in diameter cassegrain antenna. The cassegrain antenna is a special form of a dual reflector antenna which uses a main reflector following a parabolic curve and a sub reflector which follows a hyperbolic curve. Cassegrain style antennas have multiple parameters which can be tuned to achieve specific design goals. Performing a sensitivity analysis will establish relationships between design parameters, directivity, side lobe levels, and effects of strut geometry. The initial design parameters will be assumed based on typical values. Results from the sensitivity analysis will be used to provide a performance band for …

Focused Beam System Biaxial Material Characterization, Nicholas A. O'Gorman

Theses and Dissertations

Electromagnetic material characterization is the process of determining the constitutive parameters (complex permittivity and permeability) of given a sample. Due to the large number of unknowns involved, multiple unique measurements are required for material property extraction. Many measurement methods, such as waveguides and striplines, possess a rigid internal structure that the sample being measured must adhere to. This rigidity limits these methods to samples that fit within the device and inhibits oblique sample orientations, limiting the number of independent measurements that can be obtained. A focus beam system, due to being an open system with greater freedom in sample size …