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Articles 1  30 of 2032
FullText Articles in Electromagnetics and Photonics
Recursive NonLocal Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie
Recursive NonLocal Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie
Electrical and Computer Engineering Faculty Publications
In this paper, we propose a computationally efficient algorithm for video denoising that exploits temporal and spatial redundancy. The proposed method is based on nonlocal means (NLM). NLM methods have been applied successfully in various image denoising applications. In the singleframe NLM method, each output pixel is formed as a weighted sum of the center pixels of neighboring patches, within a given search window.
The weights are based on the patch intensity vector distances. The process requires computing vector distances for all of the patches in the search window. Direct extension of this method from 2D to 3D, for video ...
Combating Ground Reflection For Wireless Sensors, Ashutosh Tadkase, Nagarjun Srinivasan, Robert A. Iannucci
Combating Ground Reflection For Wireless Sensors, Ashutosh Tadkase, Nagarjun Srinivasan, Robert A. Iannucci
Bob Iannucci
Gui For MriCompatible Neural Stimulator And Recorder, Soo Han Soon, Nishant Babaria, Ranajay Mandal, Zhongming Liu
Gui For MriCompatible Neural Stimulator And Recorder, Soo Han Soon, Nishant Babaria, Ranajay Mandal, Zhongming Liu
The Summer Undergraduate Research Fellowship (SURF) Symposium
Functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) are useful tools to analyze brain activities given active stimulation. However, the electromagnetic noise from the MRI distorts the brain signal recording and damages the subject with excessive heat generated on the electrodes attached to the skin. MRIcompatible recording and stimulation systems previously developed at LIBI lab were capable of removing the electromagnetic noise during the imaging process. Previously, the hardware systems had required the integrative software that could control both circuits simultaneously and enable users to easily change recording and stimulation parameters. Graphical user interface (GUI) programmed with computer language informed ...
Optimization Of Miniaturized Resonant Microwave Cavities For Use In QThrusters, Joshua Steven Pennington
Optimization Of Miniaturized Resonant Microwave Cavities For Use In QThrusters, Joshua Steven Pennington
Theses and Dissertations
A gedankenexperiment was considered to compare a hypothetical thruster that used no reaction mass to propulsion methods currently in use. A brief discussion of previous research work done on closed resonant cavity thrust devices was conducted. Using the previous work as a template, a simulation plan was devised. Computational models of resonant microwave cavities were constructed and investigated using COMSOL software. These COMSOL simulations were verified against known analytical solutions using Matlab software as a computational tool. Multiphysics simulations were created to study the microwave heating environment of the resonant cavities. From the COMSOL study outputs, the electromagnetic field magnitude ...
Two Senior Projects: 2.4 Ghz, 40% Efficiency Radio Frequency Amplifier, Ieee Design Contest, & Design And Implementation Of A Software Costas Loop For Audio Frequencies, Robert J. Tong
Electrical Engineering
How to Read this Document:
This document combines two senior project reports. The first senior project documents designing a class AB RF amplifier. The second, discusses the design and implementation of a software Costas loop for audio frequencies. The first report begins on the next page, while the Costas loop report starts on page 24. The two reports are orthogonal from one another. It is not a prerequisite to read the RF amplifier report before reading the Costas loop report. This document is merely two reports combined into one document. The second report, about the Costas loop, was written as ...
SiBased Germanium Tin Semiconductor Lasers For Optoelectronic Applications, Sattar H. Sweilim AlKabi
SiBased Germanium Tin Semiconductor Lasers For Optoelectronic Applications, Sattar H. Sweilim AlKabi
Theses and Dissertations
Siliconbased materials and optoelectronic devices are of great interest as they could be monolithically integrated in the current Si complementary metaloxidesemiconductor (CMOS) processes. The integration of optoelectronic components on the CMOS platform has long been limited due to the unavailability of Sibased laser sources. A Sibased monolithic laser is highly desirable for full integration of Si photonics chip. In this work, Sibased germaniumtin (GeSn) lasers have been demonstrated as direct bandgap groupIV laser sources. This opens a completely new avenue from the traditional IIIV integration approach. In this work, the material and optical properties of GeSn alloys were comprehensively studied ...
LaserAssisted Metal Organic Chemical Vapor Deposition Of Gallium Nitride, Hossein Rabiee Golgir
LaserAssisted Metal Organic Chemical Vapor Deposition Of Gallium Nitride, Hossein Rabiee Golgir
Theses, Dissertations, and Student Research from Electrical & Computer Engineering
Due to its unique properties, gallium nitride is of great interest in industry applications including optoelectronics (LEDs, diode laser, detector), high power electronics, and RF and wirelss communication devices. The inherent shortcomings of current conventional deposition methods and the everincreasing demand for gallium nitride urge extended efforts for further enhancement of gallium nitride deposition. The processes of conventional methods for gallium nitride deposition, which rely on thermal heating, are inefficient energy coupling routes to drive gas reactions. A high deposition temperature (10001100 °C) is generally required to overcome the energy barriers to precursor adsorption and surface adatom migration. However, there ...
On The Simulation And Mitigation Of Anisoplanatic Optical Turbulence For Long Range Imaging, Russell C. Hardie, Daniel A. Lemaster
On The Simulation And Mitigation Of Anisoplanatic Optical Turbulence For Long Range Imaging, Russell C. Hardie, Daniel A. Lemaster
Russell C. Hardie
We describe a numerical wave propagation method for simulating long range imaging of an extended scene under anisoplanatic conditions. Our approach computes an array of point spread functions (PSFs) for a 2D grid on the object plane. The PSFs are then used in a spatially varying weighted sum operation, with an ideal image, to produce a simulated image with realistic optical turbulence degradation. To validate the simulation we compare simulated outputs with the theoretical anisoplanatic tilt correlation and differential tilt variance. This is in addition to comparing the long and shortexposure PSFs, and isoplanatic angle. Our validation analysis shows an ...
Analysis Of Various Classification Techniques For Computer Aided Detection System Of Pulmonary Nodules In Ct, Barath Narayanan Narayanan, Russell C. Hardie, Temesguen Messay
Analysis Of Various Classification Techniques For Computer Aided Detection System Of Pulmonary Nodules In Ct, Barath Narayanan Narayanan, Russell C. Hardie, Temesguen Messay
Russell C. Hardie
Lung cancer is the leading cause of cancer death in the United States. It usually exhibits its presence with the formation of pulmonary nodules. Nodules are round or ovalshaped growth present in the lung. Computed Tomography (CT) scans are used by radiologists to detect such nodules. Computer Aided Detection (CAD) of such nodules would aid in providing a second opinion to the radiologists and would be of valuable help in lung cancer screening. In this research, we study various feature selection methods for the CAD system framework proposed in FlyerScan. Algorithmic steps of FlyerScan include (i) local contrast enhancement (ii ...
Comparing Multiple Turbulence Restoration Algorithms Performance On Noisy Anisoplanatic Imagery, Michael Armand Rucci, Russell C. Hardie, Alexander J. Dapore
Comparing Multiple Turbulence Restoration Algorithms Performance On Noisy Anisoplanatic Imagery, Michael Armand Rucci, Russell C. Hardie, Alexander J. Dapore
Russell C. Hardie
In this paper, we compare the performance of multiple turbulence mitigation algorithms to restore imagery degraded by atmospheric turbulence and camera noise. In order to quantify and compare algorithm performance, imaging scenes were simulated by applying noise and varying levels of turbulence. For the simulation, a MonteCarlo wave optics approach is used to simulate the spatially and temporally varying turbulence in an image sequence. A PoissonGaussian noise mixture model is then used to add noise to the observed turbulence image set. These degraded image sets are processed with three separate restoration algorithms: Lucky Look imaging, bispectral speckle imaging, and a ...
Recursive NonLocal Means Filter For Video Denoising With PoissonGaussian Noise, Redha A. Almahdi, Russell C. Hardie
Recursive NonLocal Means Filter For Video Denoising With PoissonGaussian Noise, Redha A. Almahdi, Russell C. Hardie
Russell C. Hardie
In this paper, we describe a new recursive NonLocal means (RNLM) algorithm for video denoising that has been developed by the current authors. Furthermore, we extend this work by incorporating a PoissonGaussian noise model. Our new RNLM method provides a computationally efficient means for video denoising, and yields improved performance compared with the single frame NLM and BM3D benchmarks methods. NonLocal means (NLM) based methods of denoising have been applied successfully in various image and video sequence denoising applications. However, direct extension of this method from 2D to 3D for video processing can be computationally demanding. The RNLM approach takes ...
Recursive NonLocal Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie
Recursive NonLocal Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie
Russell C. Hardie
In this paper, we propose a computationally efficient algorithm for video denoising that exploits temporal and spatial redundancy. The proposed method is based on nonlocal means (NLM). NLM methods have been applied successfully in various image denoising applications. In the singleframe NLM method, each output pixel is formed as a weighted sum of the center pixels of neighboring patches, within a given search window. The weights are based on the patch intensity vector distances. The process requires computing vector distances for all of the patches in the search window. Direct extension of this method from 2D to 3D, for video ...
Simulation Of Anisoplanatic Imaging Through Optical Turbulence Using Numerical Wave Propagation With New Validation Analysis, Russell C. Hardie, Jonathan D. Power, Daniel A. Lemaster, Douglas R. Droege, Szymon Gladysz, Santasri BosePillai
Simulation Of Anisoplanatic Imaging Through Optical Turbulence Using Numerical Wave Propagation With New Validation Analysis, Russell C. Hardie, Jonathan D. Power, Daniel A. Lemaster, Douglas R. Droege, Szymon Gladysz, Santasri BosePillai
Russell C. Hardie
We present a numerical wave propagation method for simulating imaging of an extended scene under anisoplanatic conditions. While isoplanatic simulation is relatively common, few tools are specifically designed for simulating the imaging of extended scenes under anisoplanatic conditions. We provide a complete description of the proposed simulation tool, including the wave propagation method used. Our approach computes an array of point spread functions (PSFs) for a twodimensional grid on the object plane. The PSFs are then used in a spatially varying weighted sum operation, with an ideal image, to produce a simulated image with realistic optical turbulence degradation. The degradation ...
Block Matching And Wiener Filtering Approach To Optical Turbulence Mitigation And Its Application To Simulated And Real Imagery With Quantitative Error Analysis, Russell C. Hardie, Michael Armand Rucci, Barry K. Karch, Alexander J. Dapore
Block Matching And Wiener Filtering Approach To Optical Turbulence Mitigation And Its Application To Simulated And Real Imagery With Quantitative Error Analysis, Russell C. Hardie, Michael Armand Rucci, Barry K. Karch, Alexander J. Dapore
Russell C. Hardie
We present a blockmatching and Wiener filtering approach to atmospheric turbulence mitigation for longrange imaging of extended scenes. We evaluate the proposed method, along with some benchmark methods, using simulated and realimage sequences. The simulated data are generated with a simulation tool developed by one of the authors. These data provide objective truth and allow for quantitative error analysis. The proposed turbulence mitigation method takes a sequence of shortexposure frames of a static scene and outputs a single restored image. A blockmatching registration algorithm is used to provide geometric correction for each of the individual input frames. The registered frames ...
Second Order Phase Transition Temperature Of Single Crystals Of Gd5si1.3ge2.7 And Gd5si1.4ge2.6, Ravi L. Hadimani, Yevgen Melikhov, Deborah L. Schlagel, Thomas A. Lograsso, Kevin W. Dennis, R. William Mccallum, David C. Jiles
Second Order Phase Transition Temperature Of Single Crystals Of Gd5si1.3ge2.7 And Gd5si1.4ge2.6, Ravi L. Hadimani, Yevgen Melikhov, Deborah L. Schlagel, Thomas A. Lograsso, Kevin W. Dennis, R. William Mccallum, David C. Jiles
Thomas A. Lograsso
Gd5(Six Ge 1−x)4 has mixed phases in the composition range 0.32 < x < 0.41, which have not been widely studied. In this paper, we have synthesized and indexed single crystal samples of Gd5Si1.3 Ge 2.7 and Gd5Si1.4 Ge 2.6. We have investigated the first order and second orderphase transition temperatures of these samples using magnetic moment vs. temperature andmagnetic moment vs. magnetic field at different temperatures. We have used a modified Arrott plot technique that was developed and reported by us previously to determine the “hidden” second order phase transition temperature of the orthorhombic II phase.
Gd5(Si,Ge)4 Thin Film Displaying Large Magnetocaloric And Strain Effects Due To Magnetostructural Transition, Ravi L. Hadimani, Joao H. B. Silva, Andre M. Pereira, Devo L. Schlagel, Thomas A. Lograsso, Yang Ren, David C. Jiles, Joao P. Araújo
Gd5(Si,Ge)4 Thin Film Displaying Large Magnetocaloric And Strain Effects Due To Magnetostructural Transition, Ravi L. Hadimani, Joao H. B. Silva, Andre M. Pereira, Devo L. Schlagel, Thomas A. Lograsso, Yang Ren, David C. Jiles, Joao P. Araújo
Thomas A. Lograsso
Magnetic refrigeration based on the magnetocaloric effect is one of the best alternatives to compete with vaporcompression technology. Despite being already in its technology transfer stage, there is still room for optimization, namely, on the magnetic responses of the magnetocaloric material. In parallel, the demand for different magnetostrictive materials has been greatly enhanced due to the wide and innovative range of technologies that emerged in the last years (from structural evaluation to straintronics fields). In particular, the Gd5(Six Ge1−x)4 compounds are a family of wellknown alloys that present both giant magnetocaloric and colossal magnetostriction effects. Despite their ...
A GraphBased Formulation For Computational Characterization Of Bulk Heterojunction Morphology, Olga Wodo, Srikanta Tirthapura, Sumit Chaudhary, Baskar Ganapathysubramanian
A GraphBased Formulation For Computational Characterization Of Bulk Heterojunction Morphology, Olga Wodo, Srikanta Tirthapura, Sumit Chaudhary, Baskar Ganapathysubramanian
Srikanta Tirthapura
To improve the efficiency of organic solar cells, it is essential to understand the role of morphology and to tailor fabrication process to get desired morphologies. In this context, a comprehensive set of computational tools to quantify and classify the 2D/3D heterogeneous internal structure of thin films is invaluable. We present a graphbased framework to efficiently compute a broad suite of physically meaningful morphology descriptors. These morphology descriptors are further classified according to the physical subprocesses within OSCs – photon absorption, exciton diffusion, charge separation, and charge transport. This approach is motivated by the equivalence between a discretized 2D/3D ...
Computational EddyCurrent Probe Model For Composites, Metals And Semiconductors, L. David Sabbagh, John R. Bowler, Harold A. Sabbagh
Computational EddyCurrent Probe Model For Composites, Metals And Semiconductors, L. David Sabbagh, John R. Bowler, Harold A. Sabbagh
John R. Bowler
A comprehensive computer code for research and design studies in electromagnetic NDE is now at an advanced stage of development. It has the capability of predicting the impedance characteristics of fully threedimensional eddycurrent probes in the presence of metals, semiconductors and advanced composites. By using a combination of the conjugate gradient method applied to a matrix and fast Fourier transform techniques, the resulting algorithm is both efficient in CPU time and has modest storage requirements. The theoretical model was presented in [1].
Eddy Current Probe Impedances Due To Interaction With Advanced Composites, John R. Bowler, Harold A. Sabbagh, L. David Sabbagh
Eddy Current Probe Impedances Due To Interaction With Advanced Composites, John R. Bowler, Harold A. Sabbagh, L. David Sabbagh
John R. Bowler
Electromagnetic fields in uniaxial conductors have been studied in order to examine the induced current distributions excited by external alternating current sources. The problem is motivated by the need to evaluate eddy current testing techniques for the inspection of composites such as graphiteepoxy or boronepoxy. In particular it is important to understand how eddy currents behave in anisotropic materials, especially uniaxial conductors in which the conductivity in the axial direction may be several hundred times greater than the transverse conductivity [1].
Prediction And Analysis Of Transient EddyCurrent Probe Signals, J. R. Bowler
Prediction And Analysis Of Transient EddyCurrent Probe Signals, J. R. Bowler
John R. Bowler
In eddycurrent nondestructive evaluation, the electromagnetic field is usually excited by a probe carrying a timeharmonic current and flaw information inferred from the amplitude and phase of the probe signal. In principle, transient excitation of eddycurrents would seem to offer great advantages since the probe response contains the equivalent information of a spectrum of frequencies. This paper explores a number of basic transient solutions due to normal aircored coils and shows how the induced emf in a coil is related to its coupling coefficient.
Inversion Of Eddy Current Probe Impedance Data For Crack Reconstruction, John Bowler, D. J. Harrison, S. J. Norton
Inversion Of Eddy Current Probe Impedance Data For Crack Reconstruction, John Bowler, D. J. Harrison, S. J. Norton
John R. Bowler
The aim of eddy current inversion is to reconstruct an unknown flaw from probe signals measured as a function of probe position and frequency or time. In seeking the solution of an inverse problem, one can take advantage of an ability to solve forward problems by using predictions of probe signals calculated with a tentative estimate of the flaw. A well known inversion strategy adopted here for eddy current inversion, is that of varying the flaw estimate iteratively until the disparity between predicted and observed probe signals is minimized. Then the model flaw which gives the optimum predictions of the ...
Eddy Current Field Theory For A Flawed Conducting HalfSpace, John R. Bowler
Eddy Current Field Theory For A Flawed Conducting HalfSpace, John R. Bowler
John R. Bowler
By using dyadic Green’s functions the electromagnetic field in an unflawed conducting halfspace can be found for a general alternating current source distribution. A crack in the conductor gives rise to a secondary source which may be represented as a surface distribution of current dipoles. An integral equation for the secondary source distribution is derived and the dipole density evaluated numerically for a rectangular subsurface crack.
EddyCurrent Probe Interaction With Subsurface Cracks, John R. Bowler
EddyCurrent Probe Interaction With Subsurface Cracks, John R. Bowler
John R. Bowler
Electric current will flow around on open crack in a conductor and give rise to very abrupt variations in the field. If the crack has a negligible opening it acts as a surface barrier where the field is virtually discontinuous. Effectively the crack is then equivalent to a layer of current dipoles with the dipole orientation normal to the surface and pointing upstream. An integral equation for the dipole density has been derived for an idealised subsurface crack using the Green’s function method [1]. Numerical solutions have been found by assuming a piecewise constant dipole density and satisfying boundary ...
Pulsed EddyCurrent Measurements For The Characterization Of Thin Layers And Surface Treatments, M. J. Johnson, John R. Bowler
Pulsed EddyCurrent Measurements For The Characterization Of Thin Layers And Surface Treatments, M. J. Johnson, John R. Bowler
John R. Bowler
By using a transient excitation, eddycurrent probes exhibit a diffuse pulseecho response in the presence of stratified conductors. The response has been investigated in order to evaluate pulsed eddycurrent signals due to a single conducting layer over a uniform substrate of dissimilar conductivity. The aim of the investigation is to assess the feasibility of measuring the thickness and quality of surface treatments including the diffusion of aluminum into nickel parts and the case hardening of steel components.
Prediction Of EddyCurrent Probe Impedance Due To Surface Cracks In Ferromagnetic Steels, N. Harfield, John R. Bowler
Prediction Of EddyCurrent Probe Impedance Due To Surface Cracks In Ferromagnetic Steels, N. Harfield, John R. Bowler
John R. Bowler
Ferromagnetic steels usually have a high value of relative permeability which means that, for frequencies commonly used in eddycurrent nondestructive evaluation, the electromagnetic skindepth is typically much smaller than the depth of a crack. This behavior allows the use of approximate, thinskin theories to describe the interaction between induced eddycurrents and surfacebreaking cracks in steel. Thinskin approximations are also appropriate for use with nonmagnetic materials at sufficiently high frequency. Auld et al [1] treated the highfrequency, surfacecrack problem in aluminium using a magnetic scalar potential formulation. The surface impedance boundary condition was applied to the field on the crack faces ...
Measurement And Calculation Of Transient EddyCurrents In Layered Structures, John R. Bowler, D. J. Harrison
Measurement And Calculation Of Transient EddyCurrents In Layered Structures, John R. Bowler, D. J. Harrison
John R. Bowler
In transient eddycurrent inspection, an electromagnetic field pulse is excited in a conductor by causing a step change in the current through a coil. As this pulse propagates into the material, it is broadened by dispersion and scattered by discontinuities in the conductivity and permeability of the conductor. Subsurface defects cause part of the pulse to be scattered back to the surface of the conductor where it can be observed as a transient signal in the time domain, either as an EMF across the coil, or by direct measurement of the magnetic field using, for example, a Hall sensor. The ...
Highly Directional Receiver And Source Antennas Using Photonic Band Gap Crystals, Rana Biswas, Gary L. Tuttle, Ekmel Ozbay, Burak Temelkuran, Mihail Sigalas, KaiMing Ho
Highly Directional Receiver And Source Antennas Using Photonic Band Gap Crystals, Rana Biswas, Gary L. Tuttle, Ekmel Ozbay, Burak Temelkuran, Mihail Sigalas, KaiMing Ho
Gary Tuttle
A directional antenna made with photonic band gap structures has been presented. The directional antenna is formed with two photonic band gap structures oriented back to back and separated from each other by a distance to form a resonant cavity between the photonic band gap structures. An antenna element is placed in the resonant cavity. The resonant frequency of the cavity is tuned by adjusting the distance between the photonic band gap structures. The resonant cavity can be asymmetrical or symmetrical.
Ferromagnetism Of Magnetically Doped Topological Insulators In Crxbi2− Xte3 Thin Films, Yan Ni, Z. Zhang, Ikenna C. Nlebedim, M. Ravi Hadimani, Gary L. Tuttle, David C. Jiles
Ferromagnetism Of Magnetically Doped Topological Insulators In Crxbi2− Xte3 Thin Films, Yan Ni, Z. Zhang, Ikenna C. Nlebedim, M. Ravi Hadimani, Gary L. Tuttle, David C. Jiles
Gary Tuttle
We investigated the effect of magnetic doping on magnetic and transport properties of Bi2Te3thin films. CrxBi2−xTe3 thin films with x = 0.03, 0.14, and 0.29 were grown epitaxially on mica substrate with low surface roughness (∼0.4 nm). It is found that Cr is an electron acceptor in Bi2Te3 and increases the magnetization of CrxBi2−xTe3. When x = 0.14 and 0.29,ferromagnetism appears in CrxBi2−xTe3 thin films, where anomalous Hall effect and weak localization of magnetoconductance were observed. The Curie temperature, coercivity, and remnant Hall resistance of thin films increase with increasing Cr concentration ...
Implementation Of Range Autofocus For Sar Radar Imaging, Nicholas J. Testin, Philip Davis
Implementation Of Range Autofocus For Sar Radar Imaging, Nicholas J. Testin, Philip Davis
Honors College Capstones and Theses
The range calculation for an FMCW radar depends on accurate linear modulation. In some circumstances, linear modulation may not be available and must be corrected for. This paper describes an autofocus technique used to correct for phase error due to nonlinearities in the components of a FMCW radar. Also described here is the algorithm used in calculating the phase error and application of the phase correction with triangle modulation. Known errors were calculated at certain distances and applied to correcting the phase of data taken at similar distances. The results given were generated using a SAR working outside linear ranges.
Development Of Intermediate Band Solar Cell Through Ingan Quantum Well Structures, Kelly Mckenzie
Development Of Intermediate Band Solar Cell Through Ingan Quantum Well Structures, Kelly Mckenzie
Electrical Engineering Undergraduate Honors Theses
In the search for highefficiency solar cells, In_{x}Ga_{1x}N has come under scrutiny as a unique material with high potential. This is due to characteristics including an easily tunable bandgap, large range of potential bandgap values, and high heat resistance. However, one factor limiting its adaptation is the high density of crystal defects. In this thesis, the qualities of InGaN are discussed and the intermediate band solar cell structure is introduced. Additionally, the growth and characterization of two sets of InGaNbased solar cell devices are reported and evaluated.