Electrical and Computer Engineering Commons^™

Miniature Embedded Module For Prognostic Health Monitoring (Phm) Of Electronic Systems, Liam Moore

Theses

Sensing systems for reliability prognostics are used extensively in life- and mission- critical electronics systems. They allow monitoring of reliability stresses in real time and scheduling of preventative maintenance before system failure. However, reliability prognostics systems are, in general, large and expensive and cannot be used in lower cost, small sized or portable products.

This thesis presents a sensing module for reliability prognostics which is only 1cm in volume and uses only commercial off-the-shelf components. In its 1cm package, the module combines all the necessary elements to act as an embedded prognostic sensor system for multi axial strain, vibration, humidity …

Protection Of Embedded Systems For Applications Involving High Loading Rate Mechanical Forces, Amjad Alsakarneh

Theses

This thesis describes the development of a methodology to optimise the dimensions and mechanical properties of force-absorbing layers surrounding miniaturised embedded electronic modules subject to high mechanical compressive/impact forces and vibration. While much has been published on the mechanical protection of electronic systems in larger scale applications, where traditional mechanical shock absorbers and springs can be used to protect the electronics, little has been published on the mechanical protection of miniature electronic modules embedded in smart structures and materials where traditional methods of mechanical protection are not feasible. The generalised system concept used in this thesis is of module encapsulation …

Diamond Based-Materials: Synthesis, Characterization And Applications, Qiang Hu

USF Tampa Graduate Theses and Dissertations

The studies covered in this dissertation concentrate on the various forms of diamond films synthesized by chemical vapor deposition (CVD) method, including microwave CVD and hot filament CVD. According to crystallinity and grain size, a variety of diamond forms primarily including microcrystalline (most commonly referred to as polycrystalline) and nanocrystalline diamond films, diamond-like carbon (DLC) films were successfully synthesized. The as-grown diamond films were optimized by changing deposition pressure, volume of reactant gas hydrogen (H2) and carrier gas argon (Ar) in order to get high-quality diamond films with a smooth surface, low roughness, preferred growth orientation and high sp3 bond …

Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) with different shapes and disk-shaped Ag NP pairs with varying interparticle distance is studied using dark-field optical microscopy and spectroscopy (DFOMS). Disk-, square-, and triangular-shaped Ag NPs were fabricated on indium tin oxide-coated glass substrates by electron beam lithography. The LSPR spectra collected from single Ag NPs within 5×5 arrays using DFOMS exhibited pronounced redshifts as the NP shape changed from disk to square and to triangular. The shape-dependent experimental LSPR spectra are in good agreement with simulations using the discrete dipole approximation model, although there are small deviations in the …

Ignition Of A Large Volume Plasma With A Plasma Jet, M. Laroussi, M. A. Akman

Electrical & Computer Engineering Faculty Publications

Here we report on a method to generate a long plasma plume and to ignite a large volume plasma by means of the jet. The plasma plume is generated by our tube reactor and then introduced into a chamber where the pressure is controlled. We discovered there are three operating phases:Aphasewhere the plume length remains approximately constant, followed by a second phase where the jet increases in length as the pressure decreases. Then at pressures below 70 Torr a mode transition occurs where the plume length decreases and the plasma expands until the entire chamber is filled.

Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler

Electrical & Computer Engineering Faculty Publications

The time evolution of the ground state wave function of a zero-temperature Bose-Einstein condensate (BEC) gas is well described by the Hamiltonian Gross-Pitaevskii (GP) equation. Using a set of appropriately interleaved unitary collision-stream operators, a qubit lattice gas algorithm is devised, which on taking moments, recovers the Gross-Pitaevskii (GP) equation under diffusion ordering (time scales as length²). Unexpectedly, there is a class of initial states whose Poincaré recurrence time is extremely short and which, as the grid resolution is increased, scales with diffusion ordering (and not as length³). The spectral results of J. Yepez et al. …

Application Of Spatial Bandwidth Concepts To Mas Pole Location For Dielectric Cylinders, James Richie

Electrical and Computer Engineering Faculty Research and Publications

The concept of effective spatial bandwidth (EBW) is extended from the case of an MAS solution for perfectly conducting (PEC) cylinders to dielectric cylinders. It is shown that the ideas and results for the conducting cylinder apply in a straightforward manner to the dielectric case. For the dielectric case, there are two auxiliary surfaces. Because the EBW calculations are independent of the scatterer material, the auxiliary surface for the scattered field will follow the same guidelines for both the PEC and dielectric cases. The guidelines for the second auxiliary surface are described and verified here. Guidelines for both a plane …

6.4 Ghz Acoustic Sensor For In-Situ Monitoring Of Afm Tip Wear, T.J. Cheng, Jun Hyun Han, Michael Ziwisky, Chung-Hoon Lee, S.A. Bhave

Electrical and Computer Engineering Faculty Research and Publications

This paper demonstrates an acoustic sensor that can resolve atomic force microscopy (AFM) tip blunting with a frequency sensitivity of 0.007%. The AFM tip is fabricated on a thin film piezoelectric aluminum nitride (AlN) membrane that is excited as a film bulk acoustic resonator (FBAR). We demonstrate that cutting 0.98 μm off of the tip apex results in a resonance frequency change of 0.4MHz at 6.387GHz. This work demonstrates the potential for in-situ monitoring of AFM tip wear.

Nano-Electromechanical Zero-Dimensional Freestanding Nanogap Actuator, Jun Hyun Han, Norimasa Yoshimizu, T.J. Cheng, Michael Ziwisky, S.A. Bhave, A. Lal, Chung-Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

Micromachined free standing nanogap with metal electrodes is presented. The gap size is as small as 17 nm, and can be reduced further with electrostatic or piezoelectric actuation. The nanoscale gap is fabricated by industrial standard optical lithography and anisotropic wet chemical Si etching. Electron transport between the metal electrodes with optical stimulus enhancing photon-electron coupling (plasmon) is presented.

Quantitative Carré Differential Interference Contrast Microscopy To Assess Phase And Amplitude, Donald D. Duncan, David G. Fischer, Amanda Dayton, Scott A. Prahl

Electrical and Computer Engineering Faculty Publications and Presentations

We present a method of using an unmodified differential interference contrast microscope to acquire quantitative information on scatter and absorption of thin tissue samples. A simple calibration process is discussed that uses a standard optical wedge. Subsequently, we present a phase-stepping procedure for acquiring phase gradient information exclusive of absorption effects. The procedure results in two-dimensional maps of the local angular (polar and azimuthal) ray deviation. We demonstrate the calibration process, discuss details of the phase-stepping algorithm, and present representative results for a porcine skin sample.

Simulation And Control Of A Quadrotor Unmanned Aerial Vehicle, Michael David Schmidt

University of Kentucky Master's Theses

The ANGEL project (Aerial Network Guided Electronic Lookout) takes a systems engineering approach to the design, development, testing and implementation of a quadrotor unmanned aerial vehicle. Many current research endeavors into the field of quadrotors for use as unmanned vehicles do not utilize the broad systems approach to design and implementation. These other projects use pre-fabricated quadrotor platforms and a series of external sensors in a mock environment that is unfeasible for real world use. The ANGEL system was designed specifically for use in a combat theater where robustness and ease of control are paramount. A complete simulation model of …

Artificial Neural Network Based Fault Location For Transmission Lines, Suhaas Bhargava Ayyagari

University of Kentucky Master's Theses

This thesis focuses on detecting, classifying and locating faults on electric power transmission lines. Fault detection, fault classification and fault location have been achieved by using artificial neural networks. Feedforward networks have been employed along with backpropagation algorithm for each of the three phases in the Fault location process. Analysis on neural networks with varying number of hidden layers and neurons per hidden layer has been provided to validate the choice of the neural networks in each step. Simulation results have been provided to demonstrate that artificial neural network based methods are efficient in locating faults on transmission lines and …

Effect Of A Silicon Tip On Absorption Cross Section, Field Enhancement, And Localized Surface Plasmon Resonance Of Different Sized Gold Nanoparticles Under Evanescent Wave Illumination, Gazi Mostafa Huda

University of Kentucky Master's Theses

We have numerically investigated the influence of a nanoscale silicon tip in proximity to an illuminated gold nanoparticle. We describe how the position of the high-permittivity tip and the size of a nanoparticle impact the absorption, peak electric field and surface plasmon resonance wavelength under different illumination conditions. We detail the finite element method (FEM) approach we have used for this, whereby we specify a volume excitation field analytically and calculate the difference between this source field and the total field (i.e., scattered-field formulation). We show that a nanoscale tip can locally enhance the absorption of the particle as well …

Application Of Stochastic Diffusion For Hiding High Fidelity Encrypted Images, Jonathan Blackledge, Abdulrahman Al-Rawi

Articles

Cryptography coupled with information hiding has received increased attention in recent years and has become a major research theme because of the importance of protecting encrypted information in any Electronic Data Interchange system in a way that is both discrete and covert. One of the essential limitations in any cryptography system is that the encrypted data provides an indication on its importance which arouses suspicion and makes it vulnerable to attack. Information hiding of Steganography provides a potential solution to this issue by making the data imperceptible, the security of the hidden information being a threat only if its existence …

Using Virtual Reality To Enhance Electrical Safety And Design In The Built Environment, Martin Barrett, Jonathan Blackledge, Eugene Coyle

Articles

— Electricity and the inherent risks associated with its use in the built environment have long since been a priority for the electrical services industry and also the general public who must live and work in this environment. By its nature virtual reality has the advantage of being safe for both the user and equipment. In addition, it offers the user an opportunity to be exposed to a range of scenarios and conditions that either occur infrequently or are hazardous to replicate. This paper presents a prototype desktop virtual reality model, to enhance electrical safety and design in the built …

Dielectric And Optical Study Of Biaxial Bent-Core Nematic Liquid Crystal, S. P. Sreenilayam, M. Nagaraj, Yuri Panarin, J. K. Vij, C. Keith, C. Tschierske

Articles

We report the observation of biaxial nematic phase in a bent-core molecular system in which the biaxiality exists on a microscopic scale using polarizing microscopy, electro-optics and dielectric spectroscopy. An application of electric field induces a macroscopic biaxiality and therefore electro-optic switching. The observed electro-optic switching is explained in terms of the interaction of the ferroelectric clusters with the electric field. Dielectric spectra of the sample shows existence of low-frequency collective processes related to the microscopic polar clusters. The dielectric constant changes its sign from positive to negative and again to positive values.

The Synchronized Short-Time-Fourier-Transform: Properties And Definitions For Multichannel Source Separation., Ruairí De Fréin, Scott Rickard

Articles

This paper proposes the use of a synchronized linear transform, the synchronized short-time-Fourier-transform (sSTFT), for time-frequency analysis of anechoic mixtures. We address the short comings of the commonly used time-frequency linear transform in multichannel settings, namely the classical short-time-Fourier-transform (cSTFT). We propose a series of desirable properties for the linear transform used in a multichannel source separation scenario: stationary invertibility, relative delay, relative attenuation, and finally delay invariant relative windowed-disjoint orthogonality (DIRWDO). Multisensor source separation techniques which operate in the time-frequency domain, have an inherent error unless consideration is given to the multichannel properties proposed in this paper. The sSTFT …

Lead Silicate Glass Microsphere Resonators With Absorption-Limited Q, Pengfei Wang, Genapathy Murugan, Timothy Lee, Xian Feng, Yuliya Semenova, Qiang Wu, Wei Loh, Gilberto Brambilla, James Wilkinson, Gerald Farrell

Articles

We report the fabrication and characterization of a lead-silicate glass microsphere resonator. We show that at the wavelengths near 1555 nm high Q modes can be efficiently excited from a 109 μm diameter lead-silicate glass microsphere via evanescent coupling using a tapered silica fiber with a waist diameter of 2 μm. Resonances with Q-factors as high as 0.9×10⁷ were observed. This is very close to the theoretical material-limited Q-factor and is the highest Q-factor reported so far from a nonlinear glass microsphere.

Magnetic Resonance Image Processing Using Levy Distributed Anisotropic Diffusion, Jonathan Blackledge, Matthew Blackledge

Conference papers

We consider the physical nature of the self-diffusion of water molecules in tissue and explore how (Nuclear) Magnetic Resonance (MR) imaging may be used as a means of measuring the rate of diffusion in vivo. A discussion is presented on how these techniques may be implemented as a non-invasive means of assessing the response of tumours to novel therapeutics including some of the basic advantages and disadvantages when compared to other methods. The physical basis and mathematical models for diffusion are considered together with models for the distribution of the diffusion co-efficient including a Levy distributed model. Using a …

Morphological Analysis From Images Of Hyphal Growth Using A Fractional Dynamic Model, Jonathan Blackledge, Dan Barry

Books/Book chapters

The development of methods capable of accurately characterising the morphology of filamentous microbes represents a significant challenge to biotechnologists. This is because the productivity of many industrial fermentation processes is heavily dependent on the morphological form adopted by an organism. It is therefore of significant value if a quantitative model and associated metric(s) for morphological forms determined by complex phenotypes can be determined non-invasively, e.g. through image analysis. Specific interest is in the quantification of the branching behaviour of an organism. This is due to the link between branching frequency, biomass and metabolite production. In this paper we present a …