Engineering Commons^™

Sub-Synchronous Resonance Analysis And Detection, Igor Brandao Machado Matsuo

Electrical Engineering Dissertations

With the increasing penetration of renewable generation resources, power grids have become more susceptible to sub-synchronous resonance phenomena, especially to sub-synchronous control interaction, which produces fast-growing oscillations. The power system operation requirements for a reliable, fast and accurate detection and monitoring system for protection and mitigation purposes are increasing. Besides, risk assessment analysis during grid planning and update studies can be extremely time-consuming due to a large number of possible grid configurations and small time-steps required for the simulation of detailed electromagnetic transient (EMT) models. The first part of this dissertation aims to provide an optimized tool for SSR risk …

Pseudo-Stereo Audio Processor, Zachariah David Bunce

Electrical Engineering

Due to both technical and resource limitations, non-professional audio production must often record with a single microphone, creating a mono audio signal. Even some originally multi-channel audio files often combine the separate channels into a single channel to save memory. However, this channel limitation makes any music held within the audio duller during listening. The Pseudo-Stereo Audio Processor remedies this situation, introducing a quadrature phase shift onto a given single-channel audio signal, producing multiple phase shifted output signals. These separate fixed-phase output signals are then recombined to produce a variable phase difference, emulated two-channel version of the input signal, allowing …

Development Of A 2d Scr Catalyst On A Diesel Particulate Filter Model For Design And Control Applications To A Ultra Low Nox Aftertreatment System, Venkata Chundru

Dissertations, Master's Theses and Master's Reports

This research focuses on modeling and control of PM and NO_x in diesel engine exhaust using an SCR catalyst on a Diesel Particulate Filter (SCR-F). A 2D SCR-F model was developed that is capable of predicting internal states: 2D temperature, PM and NH₃storage distributions and filtration efficiency, pressure drop, PM mass retained in the PM cake and substrate wall and outlet NO, NO₂and NH₃concentrations. The SCR-F model was used to simulate a DOC + SCR-F + DOC + SCR ultra-low NOx system that can achieve > 99.5% NOx conversion efficiency.

The model was calibrated …

Microelectromechanical Systems Inertial Measurement Unit As An Attitude And Heading Reference System, Francisco Javier Salcedo Ortega

Open Access Theses & Dissertations

Microelectromechanical systems inertial measurement units (MEMS IMU) are an accessible technology that can be used as an attitude and heading reference system (AHRS); they are low cost and functional enough to be used in many Inertial Navigation Systems (INS). However, the gyroscope component on the IMU tends to severely drift over time without the use of filtering or other navigation systems reference such as a Global Positioning System (GPS) device. This Thesis is focused on working with a variety of IMUs to describe the accuracy, precision, and error propagation. It also works as an introductory guide to the world of …

Nanophotonics For Dark Materials, Filters, And Optical Magnetism, Mengren Man

Open Access Dissertations

Research on nanophotonic structures for three application areas is described, a near perfect optical absorber based on a graphene/dielectric stack, an ultraviolet bandpass filter formed with an aluminum/dielectric stack, and structures exhibiting homogenizable magnetic properties at infrared frequencies. The graphene stack can be treated as a effective, homogenized medium that can be designed to reflect little light and absorb an astoundingly high amount per unit thickness, making it an ideal dark material and providing a new avenue for photonic devices based on two-dimensional materials. Another material stack arrangement with thin layers of metal and insulator forms a multi-cavity filter that …

Analysis Of Waveguides Filled With Uniaxial Media And Metamaterials For Filter Applications Using The Mode Matching Method, Luke Murphy

Dissertations - ALL

This dissertation will explore the analysis of waveguide discontinuities for the purpose of dielectric filled waveguide filter analysis and design. The filling media studied are uniaxial media and uniaxial media embedded with metamaterial. A literary search provides numerous methods and numerical techniques for analyzing waveguide class problems, but ultimately the Mode Matching Method (MMM) is chosen as the numerical analysis technique for this dissertation.

An overview of waveguide theory and its application to the Mode Matching Method are presented. The Mode Matching Method is then used to analyze simple cases to confirm the numerical accuracy. Once accuracy is confirmed, Mode …

Filter Synthesis And Design Techniques For Highly Adaptable Systems, Eric James Naglich

Open Access Dissertations

Software defined radio and cognitive radio (SDR/CR) are promising concepts toward more optimally using the electromagnetic spectrum for communications and data transfer. These systems are highly agile in terms of modulation technique and frequency of operation due to early digitization and software processing of received radio frequency signals. However, the front ends of SDR/CR systems often use static antennas and switched banks of static, wide bandwidth filters before the digitization process. These components limit the ability of SDR/CR systems to operate in environments with high levels of interference and are therefore a bottleneck in the path to achieving optimal adaptation …

3d Electromagnetic Simulation Tool Exposure For Undergraduate Electrical Engineers: Incorporation Into An Analog Filters Course, Bobby B. Pheng

Master's Theses

With the growth of wireless communications, comes the need for engineers knowledgeable in 3D electromagnetic (EM) simulation of high-frequency circuits. To give electrical engineering students a better understanding of the behavior of electromagnetic fields, experiments including the use of 3D EM simulation software were proposed. Most students get lost in differential equations, curls, and divergences; this thesis aims to remedy that by exposing them to 3D EM simulation, which may motivate them toward further study in electromagnetics. Also, experience using EMPro is very beneficial for future RF/microwave/antenna engineers, as use of 3D EM simulation is becoming a requirement for this …

Art In A New Light: Design And Assessment Of Illuminants To Reduce Photochemical Degradation Of Works Of Art, Monica Fabiola Delgado

Open Access Theses & Dissertations

The purpose of this research is to design the best lighting that will minimize long term photochemical degradation of Old Master Drawings and/or other works of art, while maintaining the patron's appreciation of the object's color and detail. The present approach is a technological refinement to the basic underlying earlier work on fluorescent lighting by W. A. Thornton, W.A. at General Electric1. Thin-film dielectric, multi-coating technology is used to create filters that eliminate ultraviolet light, near infrared light and significant unnecessary parts from the visible spectrum, thus maximizing the reduction in photochemical degradation, while maintaining optimal color rendering. Three interference …

A Study Of Equatorial Ionopsheric Variability Using Signal Processing Techniques, Xiaoni Wang

Electronic Theses and Dissertations

The dependence of equatorial ionosphere on solar irradiances and geomagnetic activity are studied in this dissertation using signal processing techniques. The statistical time series, digital signal processing and wavelet methods are applied to study the ionospheric variations. The ionospheric data used are the Total Electron Content (TEC) and the critical frequency of the F2 layer (foF2). Solar irradiance data are from recent satellites, the Student Nitric Oxide Explorer (SNOE) satellite and the Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite. The Disturbance Storm-Time (Dst) index is used as a proxy of geomagnetic activity in the equatorial region. The results are summarized …

Two-Dimensional Guided Mode Resonant Structures For Spectral Filtering Applications, Sakoolkan Boonruang

Electronic Theses and Dissertations

Guided mode resonant (GMR) structures are optical devices that consist of a planar waveguide with a periodic structure either imbedded in or on the surface of the structure. The resonance anomaly in GMR structures has many applications as dielectric mirrors, tunable devices, sensors,and narrow spectral band reflection filters. A desirable response from a resonant grating filter normally includes a nearly 100% narrowband resonant spectral reflection (transmission), and a broad angular acceptance at either normal incidence or an oblique angle of incidence. This dissertation is a detailed study of the unique nature of the resonance anomaly in GMR structures with two-dimensional …

Understanding Wavelet Analysis And Filters For Engineering Applications, Chethan Bangalore Parameswariah

Doctoral Dissertations

Wavelets are signal-processing tools that have been of interest due to their characteristics and properties. Clear understanding of wavelets and their properties are a key to successful applications. Many theoretical and application-oriented papers have been written. Yet the choice of a right wavelet for a given application is an ongoing quest that has not been satisfactorily answered. This research has successfully identified certain issues, and an effort has been made to provide an understanding of wavelets by studying the wavelet filters in terms of their pole-zero and magnitude-phase characteristics. The magnitude characteristics of these filters have flat responses in both …

Optimum Monotonic Step Response Filters, Peter H. Halpern

Retrospective Theses and Dissertations

The problem of designing sharp cutoff filters with monotonic step responses is addressed. The impulse responses of the filters are expanded in terms of finite duration trigonometric polynomials. The coefficients of the trigonometric polynomials are obtained, for arbitrary frequency penalty functions, by solving a generalized eigenvalue problem. Once the trigonometric polynomial is specified the network can be synthesized with known techniques. Two theorems which assist in the numerical solution are proven.

Description Of Sand-Water Pumping Experiment And Preliminary Photographic Investigation, Allen F. Westerdahl

Bachelors Theses and Reports, 1928 - 1970

The objective of this report is threefold: to provide a brief description of the Sand-Water pumping experiment; to describe the flow of sand and water in the experimental equipment; and to present the results of a preliminary photographic investigation of fluorescent minerals in clear plastic pipes.