Engineering Commons^™

Liquid Crystal Materials And Tunable Devices For Optical Communications, Fang Du

Electronic Theses and Dissertations

In this dissertation, liquid crystal materials and devices are investigated in meeting the challenges for photonics and communications applications. The first part deals with polymer-stabilized liquid crystal (PSLC) materials and devices. Three polymer-stabilized liquid crystal systems are developed for optical communications. The second part reports the experimental investigation of a novel liquid-crystal-infiltrated photonic crystal fiber (PCF) and explores its applications in fiber-optic communications. The curing temperature is found to have significant effects on the PSLC performance. The electro-optic properties of nematic polymer network liquid crystal (PNLC) at different curing temperatures are investigated experimentally. At high curing temperature, a high contrast, …

An Analysis Of The Conventional Wire Maintenance Methods And Transition Wire Integrity Programs Utilized In The Aviation Industry., Susan Jeruto Kiptinness

Electronic Theses and Dissertations

Aging aircraft wiring poses a significant threat to both commercial and military aircraft. Recent air disasters involving aging aircraft wiring have made it clear that aging wiring can be catastrophic. Aging of an electrical wiring system can result in loss of critical functions of equipment or loss of information regarding equipment operation. Either result can lead to an electrical failure causing smoke and fire, consequently being a danger to public health and aircraft safety.

Conventional maintenance practices do not effectively manage aging wiring problems. More proactive methods are needed so that aircraft wiring failures can be anticipated and wiring systems …

Investigation And Improvement Of The Conveyor System At A Bottle Packaging Operation., Dirk Lee Fugate

Electronic Theses and Dissertations

This investigation examines the bottle packaging conveyor system and its impact on the overall efficiency at a bottle packaging plant in Anderson, South Carolina. The purpose of this study is to demonstrate the existing opportunity to reduce bottle unit cost, increase productivity, decrease the risk of work related injuries, and improve line reliability along with employee moral with the conveying system alone.

Data was gathered for this study in three ways: One, bottle packaging line lead operators were required to document the start and stop times of the conveyor system on their respective lines for six weeks. Two, a conveyor …

The Removal Of Motion Artifacts From Non-Invasive Blood Pressure Measurements, Paresh Thakkar

Electronic Theses and Dissertations

Modern Automatic Blood Pressure Measurement Techniques are based on measuring the cuff pressure and on sensing the pulsatile amplitude variations. These measurements are very sensitive to motion of the patient or the surroundings where the patient is. The slightest unexpected movements could offset the readings of the automatic Blood Pressure meter by a large amount or render the readings totally meaningless. Every effort must be taken to avoid subjecting the body of the patient or the patient's surroundings to motion for obtaining a reliable reading. But there are situations in which we need Blood Pressure Measurements with the patient or …

Raindrop Size Distribution Retrieval And Evaluation Using An S-Band Radar Profiler, Fang Fang

Electronic Theses and Dissertations

Vertical pointing Doppler radar profilers are used to explore the vertical structure of precipitation cloud systems and to provide validation information for use in weather research. In this thesis, a theoretical radar rain-backscatter model was developed to simulate profiler Doppler spectra as a function of assumed rain parameters, of which the raindrop size distribution (DSD) is the fundamental quantity used to describe the characteristics of rain. Also, profiler observations during stratiform rain are analyzed to retrieve the corresponding rain DSD’s. In particular, a gamma distribution model is introduced, which uses Rayleigh scattering portion of the Doppler velocity spectrum to estimate …

Techniques For Assessing And Improving Performance In Navigation And Wayfinding Using Mobile Augmented Reality, Brian Goldiez

Electronic Theses and Dissertations

Augmented reality is a field of technology in which the real world is overlaid with additional information from a computer generated display. Enhancements to augmented reality technology presently support limited mobility which is expected to increase in the future to provide much greater real world functionality. This work reports on a set of experiments that investigate performance in search and rescue navigating tasks using augmented reality. Augmentation consisted of a spatially and temporally registered map of a maze that was overlaid onto a real world maze. Participants were required to traverse the maze, answer spatially oriented questions in the maze, …

Hydrogen Sulfide Flux Measurements And Dispersion Modeling From Constr, Sangho Eun

Electronic Theses and Dissertations

Odor problems are a common complaint from residents living near landfills. Many compounds can cause malodorous conditions. However, hydrogen sulfide (h2s) has been identified as a principal odorous component from construction and demolition (c&d)debris landfills. Although several studies have reported the ambient concentrations of h2s near c&d landfills, few studies have quantified emission rates of h2s. The most widely used and proven technique for measuring gas emission rates from landfills is the flux chamber method. Typically the flux chamber is a cylindrical enclosure device with a spherical top which limits the gas emission area. Pure zero grade air is introduced …

Analysis Of Type And Severity Of Traffic Crashes At Signalized Intersections Using Tree-Based Regression And Ordered Probit Models, Joanne Marie Keller

Electronic Theses and Dissertations

Many studies have shown that intersections are among the most dangerous locations of a roadway network. Therefore, there is a need to understand the factors that contribute to traffic crashes at such locations. One approach is to model crash occurrences based on configuration, geometric characteristics and traffic. Instead of combining all variables and crash types to create a single statistical model, this analysis created several models that address the different factors that affect crashes, by type of collision as well as injury level, at signalized intersections. The first objective was to determine if there is a difference between important variables …

Expression Morphing Between Different Orientations, Tao Fu

Electronic Theses and Dissertations

How to generate new views based on given reference images has been an important and interesting topic in the area of image-based rendering. Two important algorithms that can be used are field morphing and view morphing. Field morphing, which is an algorithm of image morphing, generates new views based on two reference images which were taken at the same viewpoint. The most successful result of field morphing is morphing from one person's face to the other one's face. View morphing, which is an algorithm of view synthesis, generates in between views based on two reference views which were taken at …

Investigation Of Ground Penetrating Radar For Detection Of Leaking Pipelines Under Roadway Pavements And Development Of Fiber-Wrapping Repair Technique, Pedro F. Suarez

Electronic Theses and Dissertations

Nowadays, it has become a common practice to observe urban roadways undergo severe distress characterized by substantial depressions. In some cases, these pavement depressions are caused by leakages in the connecting joints of sewage pipelines laid beneath the roadway pavement. Manual inspection of pipe leakages has become costly and complex since sewage pipes with relative small diameters do not allow inspection from inside and digging may be required. On the other hand, pipes with large diameters, in which inspection can be made from pipe interior, inspector can not remain inside of the pipe for long periods of time because of …

Planar Magnetics Design For Low-Voltage Dc-Dc Converters, Shangyang Xiao

Electronic Theses and Dissertations

The objectives of this thesis are to design planar magnetic devices based on accurate electromagnetic analysis and miniaturize magnetics within desired low profile as well as small footprint. A novel methodology based on FEM simulation is proposed. By introducing Maxwell 2D simulator, optimal interleaving structures can be found to reduce AC losses that cannot otherwise be accounted for by conventional method. And 3D simulator is employed to make the results more realistic. Thus, high-efficiency high-power density magnetics is achieved.

Modeling Of Membrane Solute Mass Transfer In Ro/Nf Membrane Systems, Yu Zhao

Electronic Theses and Dissertations

Five articles describing the impact of surface characteristics, and development of mass transfer models for diffusion controlled membrane applications are published in this dissertation. Article 1 (Chapter 3) describes the impact of membrane surface characteristics and NOM on membrane performance for varying pretreatment and membranes during a field study. Surface charge, hydrophobicity and roughness varied significantly among the four membranes used in the study. Membrane surface characteristics, NOM and SUVA measurements were used to describe mass transfer in a low pressure RO integrated membrane system. Inorganic and organic solute and water mass transfer coefficients were systematically investigated for dependence on …

Biostability In Drinking Water Distribution Systems Study At Pilot-Scale, Michael Le Puil

Electronic Theses and Dissertations

Biostability and related issues (e.g. nitrification) were investigated for 18 months in 18 pilot distribution systems, under various water quality scenarios. This study specifically investigated the impact of steady-state water changes on HPC levels in chlorinated and chloraminated distribution systems. Chlorination was more effective than chloramination in reducing HPC levels (1-2 log difference). There was a rapid increase in HPC corresponding to the change in steady-state water quality, which was observed in all PDS. Modeling effort demonstrated that HPC levels reached a maximum within five days after water quality change and return to initial level ten days after the change. …

Effects Of The Soil Properties On The Maximum Dry Density Obtained Fro, Andres Arvelo

Electronic Theses and Dissertations

In the construction of highways, airports, and other structures, the compaction of soils is needed to improve its strength. In 1933 Proctor developed a laboratory compaction test to determine the maximum dry density of compacted soils, which can be used for specifications of field compaction. The Compaction of soils is influenced by many factors, the most common are the moisture content, the soil type and the applied compaction energy. The objective of this research is the analysis of the maximum dry density values based on the soil classification and characterization. The method of choice in the determination of the maximum …

Predicting Air Quality Near Roadway Intersections Through The Applicat, Brian Kim

Electronic Theses and Dissertations

With substantial health and economic impacts attached to many highway-related projects, it has become imperative that the models used to assess air quality be as accurate as possible. The United States (US) Environmental Protection Agency (EPA) currently promulgates the use of CAL3QHC to model concentrations of carbon monoxide (CO) near roadway intersections. This model uses steady-state and macroscopic methods to model the physical phenomena (e.g., emission rates, atmospheric dispersion, etc.) occurring at intersections. These methods are not straightforward and unintuitive for the users. Therefore, this project investigated the possibility of developing a model that is theoretically more realistic and flexible …

Performance Analysis Of Low-Power, Short-Range Wireless Transceivers, Usha Neupane

Electronic Theses and Dissertations

To address the various emerging standards like BluetoothTM, Home RF, Wi-fiTM (IEEE 802.11), ZigBeeTM etc., in the field of wireless communications, different transceivers have been designed to operate at various frequencies such as 450 MHz, 902-920 MHz, 2.4 GHz, all part of designated ISM band. Though, the wireless systems have become more reliable, compact and easy to develop than before, a detailed performance analysis and characterization of the devices should be done. This report details the performance analysis and characterization of a popular binary FSK transceiver TRF6901 from Texas Instruments. The performance analysis of the device is done with respect …

Modeling Crash Frequencies At Signalized Intersections In Central Flor, Smitha Kowdla

Electronic Theses and Dissertations

A high percentage of highway crashes in the United States occur at intersections. These crashes result in property damage, lost productivity, injury, and even death. Identifying intersections associated with high crash rate is very important to minimize future crashes. The purpose of this study is to develop efficient means to evaluate intersections, which may require safety improvements. The area covered by the analysis in this thesis includes Orange and Seminole Counties and the City of Orlando. The aforementioned counties and city thus represent Central Florida. Each County/City provided data that consisted of signalized intersection drawings that were either in the …

Effects Of Deposition Temperature And Post Deposition Annealing On The Electrical Properties Of Barium Strontium Titanate Thin Film For Embedded Capacitor Applications, Ranganathan, Ravip Peelamedu

Electronic Theses and Dissertations

A higher degree of system level integration can be achieved by integrating the passive components into semiconductor devices, which seem to be an enabling technology for portable communication and modern electronic devices. Greater functionality, higher performance and increase in reliability can be achieved by miniaturizing and reducing the number of components in integrated circuits. The functional potential of small electronic devices can be enormously increased by implementing the embedded capacitors, resistors and inductors. This would free up surface real estate allowing either a smaller footprint or more silicon devices to be placed on the same sized substrate. This thesis focuses …

Performance Of Interface Elements In The Finite Element Method, Kairas Rabadi

Electronic Theses and Dissertations

The objective of this research is to assess the performance of interface elements in the finite element method. Interface elements are implemented in the finite element codes such as MSC.NASTRAN, which is used in this study. Interface elements in MSC.NASTRAN provide a tool to transition between a shell-meshed region to another shell-meshed region as well as from a shell-meshed region to a solid-meshed region. Often, in practice shell elements are layered on shell elements or on solid elements without the use of interface elements. This is potentially inaccurate arising in mismatched degrees of freedom. In the case of a shell-to-shell …

Autonomous Robotic Automation Systemwith Vision Feedback, Jeffery Rosino

Electronic Theses and Dissertations

In this thesis, a full design, development and application of an autonomous robotic automation system using vision feedback is performed. To realize this system, a cylindrical manipulator configuration is implemented, using a personal computer (PC) based PID controller from National Instruments. Full autonomous control will be achieved via a programmable human machine interface (HMI) developed on a PC using Borland C++ Builder. The vision feedback position control is accomplished using an ordinary "off-the-shelf" web camera. The manuscript is organized as follows; After Chapter 1, an introduction to automation history and its role in the manufacturing industry, Chapter 2 discusses and …

Failure Mode Identifications Of Rc Beams Externally Strengthened With, Chris O'Riordan-Adjah

Electronic Theses and Dissertations

The application of carbon reinforced-fiber polymers (CFRP) to structures is a new development that is still under intense research. However, the rehabilitation or retrofit of damage reinforced concrete members by the external bonding of CFRP is becoming increasingly popular in the construction industry. The objective of the tests presented in this thesis is to study different CFRP designs on the reinforced concrete beams and compare their failure modes. The main goal is to determine the CFRP design on the reinforced concrete beams that result in a progressive and gradual failure mode with enough warning before final failure. Different CFRP designs …

Decision Support Model For Construction Crew Reassignments, Angela M. Sist

Electronic Theses and Dissertations

The reassignment of crews on a construction project in response to changes occurs on a frequent basis. The factors that affect the crew reassignment decision can be myriad and most are not known with certainty. This research addresses the need for a decision support model to assist construction managers with the crew reassignment problem. The model design makes use of certainty factors in a decision tree structure. The research helped to determine the elements in the decision tree, the appropriate combination rules to use with the certainty factors, and the method for combining the certainty factors and costs to develop …

Factors Affecting The Practices Of Iso 9001:2000 Quality Management System In Saudi Business Organizations, Mohammad Mesaad Al-Asiri

Electronic Theses and Dissertations

Since it's release in Dec 2000, there has been a slow movement towards the new version of ISO 9001:2000 by ISO 9000:1994 certified organizations. Of the 561,747 ISO 9000 certified businesses, 167,210 are certified under the new ISO 9001:2000, which is less than 30 % of the total ISO 9000 certified companies. Although many studies have been conducted to understand and assess the practices of ISO 9000:1994 standards, no research has been done to investigate the practices of ISO 9001:2000 in Saudi Arabia. This study is designed to investigate the implementation practices of the new ISO 9001:2000 standard in Saudi …

Antenna-Coupled Tunnel Diodes For Dual-Band Millimeter-Wave/Infrared F, Mohamed Abdel Rahman

Electronic Theses and Dissertations

The infrared and millimeter-wave portions of the spectrum both have their advantages for development of imaging systems. Because of the difference in wavelengths, infrared imagers offer inherently high resolution, while millimeter-wave systems have better penetration through atmospheric aerosols such as fog and smoke. Shared-aperture imaging systems employing a common focal-plane array that responds to both wavebands are desirable from the viewpoint of overall size and weight. We have developed antenna-coupled sensors that respond simultaneously at 30 THz and at 94 GHz, utilizing electron-beam lithography. Slot-antenna designs were found to be particularly suitable for coupling radiation into metal-oxide-metal (MOM) tunnel diodes …

Self Designing Pattern Recognition System Employing Multistage Classification, Manal M. Abdelwahab

Electronic Theses and Dissertations

Recently, pattern recognition/classification has received a considerable attention in diverse engineering fields such as biomedical imaging, speaker identification, fingerprint recognition, etc. In most of these applications, it is desirable to maintain the classification accuracy in the presence of corrupted and/or incomplete data. The quality of a given classification technique is measured by the computational complexity, execution time of algorithms, and the number of patterns that can be classified correctly despite any distortion. Some classification techniques that are introduced in the literature are described in Chapter one. In this dissertation, a pattern recognition approach that can be designed to have evolutionary …

Finite Element Analysis Of Left-Handed Waveguides, Balasubramaniam, Vellakkinar

Electronic Theses and Dissertations

In this work, waveguides with simultaneous negative dielectric permittivity and magnetic permeability, otherwise known as left-handed waveguides, are investigated. An approach of formulating and solving an eigenvalue problem with finite element method resulting in the dispersion relation of the waveguides is adopted in the analysis. Detailed methodology of one-dimensional scalar and two-dimensional vector finite element formulation for the analysis of grounded slab and arbitrary shaped waveguides is presented. Based on the analysis, for waveguides with conventional media, excellent agreement of results is observed between the finite element approach and the traditional approach. The method is then applied to analyze left-handed …

A Mobile Robotic Computing Platform For Three-Dimensional Indoor Mappi, Kenneth Mccoig

Electronic Theses and Dissertations

There are several industries exploring solutions to quickly and accurately digitize unexplored indoor environments, into useable three-dimensional databases. Unfortunately, there are inherent challenges to the indoor mapping process such as, scanning limitations and environment complexity, which require a specific application of tools to map an environment precisely with low cost and high speed. This thesis successfully demonstrates the design and implementation of a low cost mobile robotic computing platform with laser scanner, for quickly mapping with high resolution, urban and/or indoor environments using a gyro-enhanced orientation sensor and selectable levels of detail. In addition, a low cost alternative solution to …

Nonlinear Adaptive Estimation Andits Application To Synchronization Of Lorenz System, Yufang Jin

Electronic Theses and Dissertations

Synchronization and estimation of unknown constant parameters for Lorenz-type transmitter are studied under the assumption that one of the three state variables is not transmitted and that transmitter parameters are not known apriori. An adaptive algorithm is proposed to estimate both the state and system parameters. Since Lorenz system shows the property of sensitivity to initial conditions and evolves in different mode with parameter variation, an equivalent system is introduced. The adaptive observer is designed based on this equivalent system without any requirement on initial conditions of the observer. It is shown by Lyapunov arguments and persistent excitation analysis that …

Chemical Structure - Nonlinear Optical Property Relationships For A Series Of Two-Photon Absorbing Fluorene Molecules, Joel Mccajah Hales

Electronic Theses and Dissertations

This dissertation reports on the investigation of two-photon absorption (2PA) in a series of fluorenyl molecules. Several current and emerging technologies exploit this optical nonlinearity including two-photon fluorescence imaging, three-dimensional microfabrication, site-specific photodynamic cancer therapy and biological caging studies. The two key features of this nonlinearity which make it an ideal candidate for the above applications are its quadratic dependence on the incident irradiance and the improved penetration into absorbing media that it affords. As a consequence of the burgeoning field which exploits 2PA, it is a goal to find materials that exhibit strong two-photon absorbing capabilities. Organic materials are …

Effect Of Coriolis And Centrifugal Forces On Turbulence And Transport At High Rotation And Buoyancy Numbers, Ahmad Khalaf Sleiti

Electronic Theses and Dissertations

This study attempts to understand one of the most fundamental and challenging problems in fluid flow and heat transfer for rotating machines. The study focuses on gas turbines and electric generators for high temperature and high energy density applications, respectively, both which employ rotating cooling channels so that materials do not fail under high temperature and high stress environment. Prediction of fluid flow and heat transfer inside internal cooling channels that rotate at high rotation number and high density ratio similar to those that are existing in turbine blades and generator rotors is the main focus of this study. Both …