Engineering Commons^™

Tunable Graphene Chem-Fet And Graphene/Si Heterojunction Chemi-Diode Sensors, Amol Kumar Singh

Theses and Dissertations

Graphene, a two-dimensional material with very high charge carrier concentration, has drawn large research interest for sensing chemical species based upon charge exchange. Atomically thin 2-dimensional arrangement of carbon in hexagonal fashion in graphene, where each carbon atom is attached to 3 neighboring carbon atoms, and presence of π* and π bands imparts it many amazing properties. Some of these properties such as very high mobility, low 1/f and thermal noise, modulation of carrier concentration and Fermi level by electrical, optical, and chemical means, and very high surface to volume ratio make graphene very promising sensing material. In order to …

Cryoimaging-Microscopy Implementation For 3d Optical Imaging, Mohammad Masoudimotlagh

Theses and Dissertations

The structures and biochemistry properties of biological tissues are mostly affected by diseases. The visualization of organ structure and biochemistry helps in early detection and progression monitoring of diseases.

Although, 2D imaging has traditionally been used to gain information from the tissue, it does not accurately represent many of the structures and functions. There currently exists a need for sensitive and specific methods to show detailed information about the structure of the tissue with high resolution and in 3D. The potential advantage of the high resolution 3D images is the ability to accurately probe structural and biochemical properties of the …

Coupled Electromagnetic And Thermal Analysis And Design Optimization Of Synchronous Electric Machines, Yi Wang

Theses and Dissertations

A new technique for coupling the electromagnetic, thermal, and air-flow analysis is proposed for electronically controlled synchronous machines. A computationally efficient finite element analysis (CE-FEA) technique is employed for the electromagnetic field analysis. An equivalent circuit network is used for thermal and air-flow analysis. An iterative algorithm, which exploits the fact that the type of machines studied have very low rotor losses and also a relatively reduced dependency of core losses with temperature and load, has been developed. The overall computational time is significantly reduced in comparison with the conventional coupling method, such that the new technique is highly suitable …

Short-Term Forecasting Of Wind Speed And Wind Power Based On Bp And Adaboost_Bp, Sibei Mi

Theses and Dissertations

Due to wind is intermittent and less dispatchable, wind power fluctuates as the wind fluctuating and is uncontrollable. Therefore, when wind power accounts for a higher proportion of total electricity generation of the system, power generation plan needs to arrange according to the variation of wind power output. The way to solve the problem is forecasting the wind power.

In this paper, we focus on the wind speed and wind power forecasting in the time scales of 10min, 1h and 3h in the future. BP Neural Network and Adaboost_BP Neural Network are selected as the forecasting model for wind speed …

Optimal Dc Power Distribution System Design For Data Center With Efficiency Improvement, Xuechao Wang

Theses and Dissertations

Data Center Power Distribution design is very popular today focusing on improved energy efficiency and reduced operating cost. Conventionally data centers use low efficiency electrical power distribution systems with large AC power transformers, high power losses, and AC UPS and PDU power conversions. Most IT servers utilize low voltage level (12V or 48V) as the power source, which requires a step-down transformer and AC to DC rectifiers in every PDU. The "Proposed 380V DC Power Distribution System" promises to deliver high transmission efficiency and low power component cost.

This is a comprehensive design including data center physical architecture and equipment …

Propagation Of An Optical Vortex In Fiber Arrays With Triangular Lattices, Muhammad Abdulrahman Mushref

Theses and Dissertations

The propagation of optical vortices (OVs) in linear and nonlinear media is an important field of research in science and engineering. The most important goal is to explore the properties of guiding dynamics for potential applications such as sensing, all-optical switching, frequency mixing and modulation. In this dissertation, we present analytical methods and numerical techniques to investigate the propagation of an optical vortex in fiber array waveguides. Analytically, we model wave propagation in a waveguide by coupled mode Equations as a simplified approximation. The beam propagation method (BPM) is also employed to numerically solve the paraxial wave Equation by finite …

Verifying Molecular Dynamics Using Dielectric Spectroscopy, Joshua Dee Smith

Theses and Dissertations

The electrical properties of proteins in solution are important for their structure and function. Computational biophysics studies of proteins need accurate parameters to ensure that numerical simulations match physical reality. Past work in this eld has compared the electrical properties of proteins obtained from dielectric spectroscopy to numerical simulations of proteins in water with adjustment of pKa values to try to capture the inevitable changes in electrical conformation that will occur in a complex structure such as a folded protein. However, fundamental veri cation of the charge parameters of the amino acid building blocks in common molecular dynamics software packages …

Design And Analysis Of Receiver Systems In Satellite Communications And Uav Navigation Radar, Matthew Robertson Morin

Theses and Dissertations

The design of a low cost electronically steered array feed (ESAF) is implemented and tested. The ESAF demonstrated satellite tracking capabilities over four degrees. The system was compared to a commercial low-noise block downconverter (LNBF) and was able to receive the signal over a wider angle than the commercial system. Its signal-to-noise ratio (SNR) performance was poor, but a proof of concept for a low cost ESAF used for tracking is demonstrated. Two compact low profile dual circularly polarized (CP) reflector feed antenna designs are also analyzed. One of the designs is a passive antenna dipole array over an electromagnetic …

Recursive-Ransac: A Novel Algorithm For Tracking Multiple Targets In Clutter, Peter C. Niedfeldt

Theses and Dissertations

Multiple target tracking (MTT) is the process of identifying the number of targets present in a surveillance region and the state estimates, or track, of each target. MTT remains a challenging problem due to the NP-hard data association step, where unlabeled measurements are identified as either a measurement of an existing target, a new target, or a spurious measurement called clutter. Existing techniques suffer from at least one of the following drawbacks: divergence in clutter, underlying assumptions on the number of targets, high computational complexity, time-consuming implementation, poor performance at low detection rates, and/or poor track continuity. Our goal is …

Scalable System Design For Covert Mimo Communications, Jason R. Pennington

Theses and Dissertations

In modern communication systems, bandwidth is a limited commodity. Bandwidth efficient systems are needed to meet the demands of the ever-increasing amount of data that users share. Of particular interest is the U.S. Military, where high-resolution pictures and video are used and shared. In these environments, covert communications are necessary while still providing high data rates. The promise of multi-antenna systems providing higher data rates has been shown on a small scale, but limitations in hardware prevent large systems from being implemented.

Proton Damage Effects On Carbon Nanotube Field-Effect Transistors, Evan R. Kemp

Theses and Dissertations

This research investigated the effects of proton damage on single-walled carbon nanotube (SWCNT) transistors. The transistors were irradiated by 1.8 MeV protons to determine the damage induced in the SWCNTs and the device substrate using Raman spectroscopy, and to observe the effect on transistor functionality by measuring current-voltage characteristics. Irradiation of the SWCNT transistors to a fluence of 1x10¹³ protons/cm² resulted in 67% increase in the Raman D/G peak intensity ratio, while at a fluence of 2x10¹³ protons/cm² the increase in the D/G ratio was only 18%, likely due to radiation annealing. Current-voltage measurements indicated an …

Single Event Mitigation For Aurora Protocol Based Mgt Fpga Designs In Space Environments, Alexander Stanley Harding

Theses and Dissertations

This work has extended an existing Aurora protocol for high-speed serial I/O between FPGAs to provide greater fault recovery in the presence of high-energy radiation. To improve on the Aurora protocol, additional resets that affect larger portions of the system were used. Detection for additional error modes that occurred but were not detected by the Aurora protocol was designed. Radiation testing was performed on the Aurora protocol with the additional mitigation hardware. The test gathered large amounts of data on the various error modes of the Aurora protocol and how the additional mitigation circuitry affected the system. The test results …

Target Motion Estimation Techniques For Single-Channel Sar, Mark T. Crockett

Theses and Dissertations

Synthetic aperture radar (SAR) systems are versatile, high-resolution radar imagers useful for providing detailed intelligence, surveillance, and reconnaissance, especially when atmospheric conditions are non-ideal for optical imagers. However, moving targets in SAR images are smeared. Along-track interferometry is a commonly-used method for extracting the motion parameters of moving targets but requires a dual-aperture SAR system, which may be power- size- or cost-prohibitive. This thesis presents a method of estimating target motion parameters in single-channel SAR data given geometric target motion constraints. I test this method on both simulated and actual SAR data. This estimation method includes an initial estimate, computation …

Signal-To-Noise Measurements And Particle Focusing In Liquid-Core Waveguides, Michael A. Olson

Theses and Dissertations

This thesis presents an analysis of the signal-to-noise ratio in liquid core anti-resonant reflecting optical waveguides (ARROWs) and the application of hydrodynamic focusing to the waveguides. These concepts are presented as a method to improve the detection capabilities of the ARROW platform. The improvements are specifically targeted at achieving single molecule detection (SMD) with the devices. To analyze the SNR of the waveguides a test platform was designed and fabricated. This test platform was then used to examine relationship between the SNR and the location of the excitation region. It was determined that the excitation region should be moved closer …

Enhancement To Camera Calibration: Representation, Robust Statistics, And 3d Calibration Tool, Qiaotian Li

Theses and Dissertations

This thesis demonstrates theenhancement to camera calibrationin three aspects: representation of pose, robust statistics and 3D calibration tool. Camera calibration is the reconstruction of digital camera information based on digital images of an object in 3D space, since the digital images are 2D projections of a 3D object onto the camera sensor. Camera calibration is the estimation of the interior orientation (IO) parameters and exterior orientation (EO) parameters of a digital camera. Camera calibration is an essential part of image metrology. If the quality of camera calibration cannot be guaranteed, neither can the reliability of the subsequent analysis and applications …

System Theoretic Analysis Of Battery Equalization Systems, Haoqi Chen

Theses and Dissertations

Battery equalizers are widely used in multi-battery systems to maintain balanced charge among individual battery cells. While the research on the hardware realization of battery equalizers has received significant attention, rigorous analysis of battery equalization from the system's point of view remains largely unexplored. In this research, we study three types of battery equalization system structures: series-based, layer-based, and module-based. Specifically, we develop mathematical models that describe the system-level behavior of the battery equalization processes under these equalization structures. Then, based on the mathematical models, analytical methods are derived to evaluate the performance of the equalization processes. We also carry …

Design Of A Micro-Focus X-Ray Source Validated By Model Protein Crystals, Lavanya Ramachandran

Theses and Dissertations

The main objective of this thesis was to build a Laboratory Microfocus X-ray Source for Protein Crystallography (LMXS-PC), an X-ray source that would provide prospective users programmatic control and remote capability.

A study of the crystal was conducted using Photoactive Yellow protein (PYP) and cytochrome c nitrite reductase (ccNiR). The instrument was then tested by mounting the crystal in the instrument and collecting data.

The other objective of my research work was to determine the crystal structure of PYP using X-ray crystallography techniques. I attempted many trials in PYP crystal in an effort to achieve a high-quality diffraction pattern; however, …

Monitoring Changes In Hemodynamics Following Optogenetic Stimulation, Seth Thomas Frye

Theses and Dissertations

The brain is composed of billions of neurons, all of which connected through a vast network. After years of study and applications of different technologies and techniques, there are still more questions than answers when it comes to the fundamental functions of the brain. This project aims to provide a new tool which can be used to gain a better understanding of the fundamental mechanisms that govern neurological processes inside the brain. In order for neural networks to operate, blood has to be supplied through neighboring blood vessels. As such, the increase or decrease in the blood supply has been …

Optical Studies Of Oxidative Stress In Lung Tissue: Rodent Models, Reyhaneh Sepehr

Theses and Dissertations

Objectives: There currently exists a need for reliable measurements of tissue metabolic state at cellular levels. The objective of this research was to study tools capable of evaluating cellular redox states in intact tissue. To meet this goal, three different instruments (cryoimager, fluorometer, and fluorescent microscope) were used to study the metabolism and functions of the mitochondria at different levels and regimes (cryo, ex vivo, in vivo and in vitro).

Introduction: Through optical monitoring of autofluorescent mitochondrial metabolic coenzymes, as well as exogenous fluorophores, the state of mitochondria can be probed in real time in many intact organs and in …

Modeling And Protection Scheme For Ieee 34 Radial Distribution Feeder With And Without Distributed Generation, Sidharth Parmar Ashok

Theses and Dissertations

The existing power system was not designed with distribution generation (DG) in mind. As DG penetration is being considered by many distribution utilities, there is a rising need to address many incompatibility issues which puts a big emphasis on the need to review and implement suitable protection scheme. The usual practice for existing distribution feeders is the Overcurrent scheme which includes coordination between fuses and reclosers. But when DG is added to the distribution feeder, the configuration is no more radial as there is contribution of fault currents from the DG's and if the existing protection scheme is applied then …

Transverse Anderson Localization In Disordered Optical Fibers, Salman Karbasivalashani

Theses and Dissertations

In any wave-guiding system, disorder and randomness in the wave propagation medium are

considered as annoyances that result in wave scattering and inefficient wave transport. In contrast, in this work, the disorder is utilized in the transverse directions of an optical fiber for an effective light transport. The transversely disordered refractive index profile is invariant along the direction of propagation that results in transverse Anderson localization of light. A launched beam of light into the disordered fiber initially expands until it reaches the localization regime then propagates without further expansion in the transverse directions.

A disordered polymer optical fiber composed …

Infrared Leaky Wave Antenna Coupled Bolometer, Navaneeth Premkumar

Theses and Dissertations

A four-element infrared leaky-wave antenna coupled bolometer was investigated with the goal of characterizing signal extraction as a long wave infrared (LWIR) detector. Simulations were carried out using Ansys HFSS. Various simple loading techniques were seen and their behavior characterized. A transmission line loaded antenna coupled bolometer was investigated using an incident-wave excitation and angle of sensing inaccuracies were observed. A position pertaining to the design criterion of angular scanning in frequency was then parametrically tuned for. The leaky-wave antenna was then simulated in the transmitting scenario. A waveport fed case was explored and far-field pattern generated. Transmission line losses …

Resonant Coupling Of An Infrared Metasurface With Pmma, Michael Francis Finch

Theses and Dissertations

Resonance coupling between a metasurface or planar metamaterial and PMMA’s, polymethyl methacrylate, phonon resonance corresponding to the C=O molecular bond at 1733 cm-1 (52 THz) is investigated. Two metasurfaces, nano rod and nano slot, are modeled using ANSYS HFSS and measured material optical properties for gold and PMMA in inferred spectrum. Both metasurfaces exhibited normal mode splitting also known as avoidance crossing, quantum level repulsion, or vacuum Rabi splitting. Normal mode splitting is shown to be a result of coupling between the PMMA phonon resonance and the resonance of the metasurface. Analytical models, which are tied to physical descriptions, are …

Power Side-Channel Dac Implementations For Xilinx Fpgas, Daniel Chase Savory

Theses and Dissertations

This thesis presents a novel power side-channel DAC (PS-DAC) which is constructed from user-controllable short circuits in FPGAs and which manipulate overall system power through dynamic power dissipation. Alternately, similar PS-DACs are created using shift-register primitives(SRL16E) which manipulate system power through switching logic, for means of comparison with short-circuit-based PS-DACs. PS-DACs are created of various sizes using both short-circuit-based and shift-register-based methods. These PS-DACs are characterized in terms of output linearity,monotonicity, and frequency distortion. Applications explored in this thesis which use PS-DAC technology include a Simple Power Analysis (SPA) side-channel transmitter, and a frequency watermarking application. These applications serve as …

Passive And Electronically Steered Array Planar Feeds For Satellite Communications, Kyle C. Browning

Theses and Dissertations

As the need for more bandwidth increases, satellite communication (SatCom) terminals are forced to climb higher in frequency. Higher frequency means greater propagation losses, and so antenna gain and sensitivity have to increase. The higher the gain, the more difficult it is to point the antenna. To make matters even more challenging, consumers are requesting satellite links in harsher environments and on moving vehicle and planes. In order to meet today's challenges and improve on dish feeds, research is ongoing to replace fixed-beam feedhorns with smaller, cheaper, and lighter PCB based antennas and to develop low-cost electronically steered array feeds …

Application Improvements Of Slab-Coupled Optical Fiber Sensors, Spencer L. Chadderdon

Theses and Dissertations

This dissertation explores techniques for improving slab-coupled optical fiber sensor (SCOS) technology for use in specific applications and sensing configurations. SCOS are advantageous for their small size and all-dielectric composition which permit non-intrusive measurement of electric fields within compact environments; however, their small size also limits their sensitivity. This work performs a thorough analysis of the factors contributing to the performance of SCOS and demonstrates methods which improve SCOS, while maintaining its small dimensions and high level of directional sensitivity. These improvements include increasing the sensitivity by 9x, improving the frequency response to include sub 300 kHz frequencies, and developing …

Airborne Wireless Communication Modeling And Analysis With Matlab, Matthew J. Vincie

Theses and Dissertations

Over the past decade, there has been a dramatic increase in the use of unmanned aerial vehicles (UAV) for military, commercial, and private applications. Critical to maintaining control and a use for these systems is the development of wireless networking systems [1]. Computer simulation has increasingly become a key player in airborne networking developments though the accuracy and credibility of network simulations has become a topic of increasing scrutiny [2-5]. Much of the inaccuracies seen in simulation are due to inaccurate modeling of the physical layer of the communication system. This research develops a physical layer model that combines antenna …

Electrical Characterization Of Spherical Copper Oxide Memristive Array Sensors, James P. Orta

Theses and Dissertations

A new System Protection (SP) technology is explored by using electrical and mechanical interference-sensing devices that are implemented with granular memristive material. The granular materials consist of oxide-coated copper spheres with radii of about 700 µm that are placed in contact to produce thin oxide junctions which exhibit memristive behavior. Processes for etching, which compared acetic acid and nitric acid etches, and thermal oxidation at 100°C are performed and compared to produce copper spheres with a copper oxide layer over the sphere surface. Oxidized copper spheres are tested as sensor arrays by loading into a capillary tube in an aligned …

Gps Multipath Reduction With Correlator Beamforming, Jason M. Barhorst

Theses and Dissertations

This research effort investigates the feasibility of beamforming using a single Global Positioning System (GPS) front end. Traditional methods of beamforming use multiple front ends, typically one per antenna element. By enabling a receiver to sample a switched antenna array, the hardware cost of implementing a GPS antenna array can be significantly reduced. Similar techniques of reducing the number of receivers have been used by Locata Corporation in the design of their non-GPS positioning systems. However, Locata Corporation's local transmitters provide a signal strength much higher than GPS's signal strength. For this reason, the inclusion of low-noise amplifiers into the …

Modulation And Synchronization For Aeronautical Telemetry, Christopher G. Shaw

Theses and Dissertations

Aeronautical telemetry systems have historically been implemented with constant envelope modulations like CPM. Shifts in system constraints including reduced available bandwidth and increased throughput demands have caused many in the field to reevaluate traditional methods and design practices. This work examines the costs and benefits of using APSK for aeronautical telemetry instead of CPM. Variable rate turbo codes are used to improve the power efficiency of 16- and 32-APSK. Spectral regrowth in nonlinear power amplifiers when driven by non-constant envelope modulation is also considered. Simulation results show the improved spectral efficiency of this modulation scheme over those currently defined in …