Engineering Commons^™

Electromagnetic Propagation Prediction Inside Aircraft Cabins, Genevieve Hankins

Electrical & Computer Engineering Theses & Dissertations

Electromagnetic propagation models for signal strength prediction within aircraft cabins are essential for evaluating and designing a wireless communication system to be implemented onboard aircraft. There are many commercially available software packages for predicting wireless system performance in conventional indoor environments. It is of interest to examine the available software to determine if the aircraft's electromagnetic environment (EME) can be modeled successfully without developing an aircraft specific prediction tool. EnterprisePlanner ®, a registered product of Wireless Valley Communications, Incorporated, was selected for the present effort. The performance of the prediction model was evaluated through a comparison with field measurements taken …

Modeling And Simulation Of \Sub-Microsecond Electrical Breakdown In Liquids With Application To Water, Jun Qian

Electrical & Computer Engineering Theses & Dissertations

In this dissertation, the inherent physics and sub-microsecond electrical breakdown of water stressed to high voltages is analyzed, and several relevant models are constructed for quantitative analysis. A bubble-based, drift-diffusion (DD) model proposed here includes almost all the important physical process of the system, and successfully explains many important features routinely observed in sub-microsecond water electrical breakdown. Here many physical properties and response characteristics typical for high-field stressing of liquid water have been analyzed through numerical calculations. The internal temperature profile in the water system has been calculated by Finite Difference Time Domain (FDTD) method to probe possible heating and …

High Power 121.6 Nm Radiation Source For Advanced Lithography, Jianxun Yan

Electrical & Computer Engineering Theses & Dissertations

A novel high power 121.6 nm radiation source based on dielectric barrier discharge (DBD) has been developed for advanced lithography applications. The discharge unit consists basically of a hollow tube made of a dielectric material with two loop-electrodes wrapped on the outside of the tube. The discharge is generated inside the tube by means of a 13.56 MHz RF power system. The discharge unit is located in a vacuum chamber that provides a dynamic gas flow and windows for radiation transmission.

A very intense and spectrally clean Lyman-α line at 121.6 nm was observed by operating the DBD discharge in …

Design And Implementation Of One And Two-Degree-Of-Freedom Magnetic Suspension And Balance Systems, Mark W. Adams

Electrical & Computer Engineering Theses & Dissertations

The main objectives of this research were to design and implement one and two-degree-of-freedom (1 DOF and 2-DOF) magnetic levitation systems to levitate permanent magnet cores contained in PVC pipes, 8.4 cm and 76.2 cm in length, respectively. This project used the components of a Magnetic Suspension and Balance System (MSBS) that is being built to provide obstruction free positioning of test models in six degrees of freedom (6-DOF) inside the Princeton University/Office of Naval Research High Reynolds Number Test Facility (HRTF). The HRTF, a specialized wind tunnel designed to simulate undersea conditions by creating a low-speed, 3500 PSI air …

Carbon Nanotubes And Tungsten Oxide Nanorods: Synthesis And Applications, Bing Xiao

Electrical & Computer Engineering Theses & Dissertations

Synthesis and applications of two types of one-dimensional nanomaterials, carbon nanotubes (CNTs) and tungsten oxide nanorods, are investigated in this dissertation. Multi-walled CNTs have been successfully synthesized using two types of chemical vapor deposition (CVD) methods: microwave plasma enhanced CVD and atmospheric pressure thermal CVD. CNTs and their synthesis processes are characterized with various analysis techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and optical emission spectroscopy. Ultra-thin and high quality multi-walled CNTs are discovered in CNT films produced by MPCVD, which exhibit good field emission performance that is found to be dependent on the synthesis …

Melting And Solidification Study Of Indium And Bismuth Nanocrystals Using Reflection High-Energy Electron Diffraction, Mohamed K. Zayed

Electrical & Computer Engineering Theses & Dissertations

As technology begins to utilize nanocrystals for many chemical, biological, medical, electrical, and optoelectrical applications, there is a growing need for an understanding of their fundamental properties. The study of melting and solidification of nanocrystals is of interest to fundamental understanding of the effect of reduced size and crystal shape on the solid-liquid phase transition. Melting and solidification of as-deposited and recrystallized indium and bismuth nanocrystals were studied using reflection high-energy electron diffraction (RHEED). The nanocrystals were thermally deposited on highly oriented 002-graphite substrate at different deposition temperatures. The growth dynamics of the nanocrystals was studied using in situ RHEED …

Multi-Modal Enhancement Techniques For Visibility Improvement Of Digital Images, Li Tao

Electrical & Computer Engineering Theses & Dissertations

Image enhancement techniques for visibility improvement of 8-bit color digital images based on spatial domain, wavelet transform domain, and multiple image fusion approaches are investigated in this dissertation research.

In the category of spatial domain approach, two enhancement algorithms are developed to deal with problems associated with images captured from scenes with high dynamic ranges. The first technique is based on an illuminance-reflectance (I-R) model of the scene irradiance. The dynamic range compression of the input image is achieved by a nonlinear transformation of the estimated illuminance based on a windowed inverse sigmoid transfer function. A single-scale neighborhood dependent contrast …

Modeling And Simulation Of Photonic Crystal Fibers And Distributed Feedback Photonic Crystal Fiber Lasers, Feng Wu

Electrical & Computer Engineering Theses & Dissertations

A photonic crystal fiber (PCF) is comprised of a solid or air core surrounded by periodically arranged air holes running along the length of the fiber, which guides light in a fundamentally new way compared to conventional optical fibers, affecting almost all areas of optics and photonics. To analyze the dispersion and loss properties of PCFs, a two-dimensional (2D) finite-difference frequency-domain (FDFD) method combined with the technique of perfectly matched layer (PML) is developed. The propagation constant and loss can be obtained with accuracies in the orders of ∼10-6 and ∼10 -3, respectively.

The Bragg fiber is a kind of …