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open access

Characterization of Boron Nitride Thin Films on Silicon (100) Wafer.

Description: Cubic boron nitride (cBN) thin films offer attractive mechanical and electrical properties. The synthesis of cBN films have been deposited using both physical and chemical vapor deposition methods, which generate internal residual, stresses that result in delamination of the film from substrates. Boron nitride films were deposited using electron beam evaporation without bias voltage and nitrogen bombardment (to reduce stresses) were characterize using FTIR, XRD, SEM, EDS, TEM, and AFM technique… more
Date: August 2007
Creator: Maranon, Walter
Item Type: Refine your search to only Thesis or Dissertation
open access

Computer Virus Spread Containment Using Feedback Control.

Description: In this research, a security architecture based on the feedback control theory has been proposed. The first loop has been designed, developed and tested. The architecture proposes a feedback model with many controllers located at different stages of network. The controller at each stage gives feedback to the one at higher level and a decision about network security is taken. The first loop implemented in this thesis detects one important anomaly of virus attack, rate of outgoing connection. Tho… more
Date: December 2004
Creator: Yelimeli Guruprasad, Arun
Item Type: Refine your search to only Thesis or Dissertation
open access

Cost Savings Realized Through Proper Sizing of an Excessive Instrument Air System.

Description: The purpose of this research was to determine if installing a smaller air compressor could reduce the electrical usage of a large semiconductor manufacturing plant. A 200 horsepower Atlas Copco compressor was installed with the existing 500 horsepower Ingersoll-Rand compressors. Testing was conducted during the regular manufacturing process at MEMC Southwest in Sherman, Texas. Analysis of the data found that installing the new compressor could reduce electrical consumption. The study also found… more
Date: December 2003
Creator: Condron, Ewell D.
Item Type: Refine your search to only Thesis or Dissertation
open access

Determination of the Shelf Life of Aluminum Electrolytic Capacitors.

Description: The aluminum electrolytic capacitor is used extensively in the electric utility industry. A factor limiting the storage of spare capacitors is the integrity of the aluminum oxide dielectric, which over time breaks down contributing to a shelf life currently estimated at one nuclear power electric generating station to be approximately five years. This project examined the electrical characteristics of naturally aged capacitors of several different styles to determine if design parameters were… more
Date: May 2002
Creator: Wynne, Edward McFaddin
Item Type: Refine your search to only Thesis or Dissertation
open access

Effect of Amines as Corrosion Inhibitors for a Low Carbon Steel in Power Industry

Description: Commonly used amines in power industry, including morpholine, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), and DMA (dimethylallylamine) were evaluated for their effect on AISI 1018 steel at 250oF. Samples were exposed to an autoclave containing amine added aqueous solution at pH of 9.5 for 1, 2, 4, 6, 8, and 12 hours. Morphology studies were carried using scanning electron microscope (SEM), phase analysis was done utilizing Fourier transform infrared spectroscopy (FTIR), and weight loss was perfor… more
Date: December 2004
Creator: Díaz, Jorge G.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effects of a Surface Engineered Metallic Coating on Elastomeric Valve Stem Seal Leakage

Description: Valve stem seal leakage is a major source of fugitive emissions, and controlling these emissions can result in added expense in leak detection and repair programs. Elastomeric O-rings can be used as valve stem seals, and O-ring manufacturers recommend lubrication of elastomeric seals to prevent damage and to assure proper sealing. In this research, a metallic coating was applied as a lubricant using a vacuum vapor deposition process to the surface of elastomeric valve stem seals. Valve stem le… more
Date: December 2000
Creator: Taylor, John Abner
Item Type: Refine your search to only Thesis or Dissertation
open access

FEM of nanoindentation on micro- and nanocrystalline Ni: Analysis of factors affecting hardness and modulus values.

Description: Nanoindentation is a widely used technique to measure the mechanical properties of films with thickness ranging from nanometers to micrometers. A much better understanding of the contact mechanics is obtained mostly through finite element modeling. The experiments were modeled using the software package Nano SP1 that is based on COSMOSM™ (Structural Research & Analysis Corp, www.cosmosm.com), a finite element code. The fundamental material properties affecting pile-up are the ratio of the effec… more
Date: August 2005
Creator: Pothapragada, Raja Mahesh
Item Type: Refine your search to only Thesis or Dissertation
open access

Flow Accelerated Corrosion Experience at Comanche Peak Steam Electric Station

Description: Flow accelerated corrosion (FAC) is a major concern in the power industry as it causes thinning of the pipes by the dissolution of the passive oxide layer formed on the pipe surface. Present research deals with comparing the protection offered by the magnetite (Fe3O4) versus maghemite (γ-Fe2O3) phases thickness loss measurements. Fourier transform infrared spectroscopy (FTIR) is used in distinguishing these two elusive phases of iron oxides. Representative pipes are collected from high pressure… more
Date: May 2008
Creator: Nakka, Ravi Kumar
Item Type: Refine your search to only Thesis or Dissertation
open access

FPGA Prototyping of a Watermarking Algorithm for MPEG-4

Description: In the immediate future, multimedia product distribution through the Internet will become main stream. However, it can also have the side effect of unauthorized duplication and distribution of multimedia products. That effect could be a critical challenge to the legal ownership of copyright and intellectual property. Many schemes have been proposed to address these issues; one is digital watermarking which is appropriate for image and video copyright protection. Videos distributed via the Inter… more
Date: May 2007
Creator: Cai, Wei
Item Type: Refine your search to only Thesis or Dissertation
open access

Indoor Propagation Modeling at 2.4 GHz for IEEE 802.11 Networks

Description: Indoor use of wireless systems poses one of the biggest design challenges. It is difficult to predict the propagation of a radio frequency wave in an indoor environment. To assist in deploying the above systems, characterization of the indoor radio propagation channel is essential. The contributions of this work are two-folds. First, in order to build a model, extensive field strength measurements are carried out inside two different buildings. Then, path loss exponents from log-distance path l… more
Date: December 2005
Creator: Tummala, Dinesh
Item Type: Refine your search to only Thesis or Dissertation
open access

Investigation of the feasibility of non-invasive carbon dioxide detection using spectroscopy in the visible spectrum.

Description: Pulse oximeters are used in operating rooms and recovery rooms as a monitoring device for oxygen in the respiratory system of the patient. The advantage of pulse oximeters over other methods of oxygen monitoring is that they are easy to use and they are non-invasive, which means it is not necessary break the skin to extract blood for information to be obtained. The standard for the measurement of partial pressure of CO2 and O2 is an arterial blood gas analysis (ABG). However routine monitoring … more
Date: December 2007
Creator: Marks, Damian
Item Type: Refine your search to only Thesis or Dissertation
open access

Laser Cutting Machine: Justification of initial costs

Description: The Industrial Laser is firmly established in metalcutting as the tool of choice for many applications. The elevator division of Montgomery KONE Inc., in an effort to move towards quality, ontime, complete deliveries and 100% customer satisfaction, decided to invest in new equipment to improve manufacturing processes. A huge investment is proposed for a laser-cutting machine. It is the responsibility of Manufacturing Engineering to direct the management by justifying its benefits, which include… more
Date: May 2001
Creator: Nagaraja, Dwarakish
Item Type: Refine your search to only Thesis or Dissertation
open access

Linearity and monotonicity of a 10-bit, 125 MHz, segmented current steering digital to analog converter

Description: The purpose of this research is to determine the linearity and monotonicity of the THS5651IDW digital to analog converter (DAC), a prototype of the future Texas Instruments TLV5651, 10-bit, 125 MHz communication DAC. Testing was conducted at the Texas Instruments facility on Forest Lane, Dallas, Texas. Texas Instruments provided test equipment, software and laboratory space to obtain test data. Analysis of the data found the DAC to be monotonic since the magnitude of the differential nonlineari… more
Date: May 2000
Creator: Bittle, Charles C.
Item Type: Refine your search to only Thesis or Dissertation
open access

Liquid Nitrogen Propulsion Systems for Automotive Applications: Calculation of Mechanical Efficiency of a Dual, Double-acting Piston Propulsion System

Description: A dual, double-acting propulsion system is analyzed to determine how efficiently it can convert the potential energy available from liquid nitrogen into useful work. The two double-acting pistons (high- and low-pressure) were analyzed by using a Matlab-Simulink computer simulation to determine their respective mechanical efficiencies. The flow circuit for the entire system was analyzed by using flow circuit analysis software to determine pressure losses throughout the system at the required mas… more
Date: May 2008
Creator: North, Thomas B.
Item Type: Refine your search to only Thesis or Dissertation
open access

MBE Growth and Instrumentation

Description: This thesis mainly aims at application of principles of engineering technology in the field of molecular beam epitaxy (MBE). MBE is a versatile technique for growing epitaxial thin films of semiconductors and metals by impinging molecular beams of atoms onto a heated substrate under ultra-high vacuum (UHV) conditions. Here, a LabVIEW® (laboratory virtual instrument engineering workbench) software (National Instruments Corp., http://www.ni.com/legal/termsofuse/unitedstates/usH) program is dev… more
Date: May 2006
Creator: Tarigopula, Sriteja
Item Type: Refine your search to only Thesis or Dissertation
open access

Preliminary design of a cryogenic thermoelectric generator.

Description: A cryogenic thermoelectric generator is proposed to increase the efficiency of a vehicle propulsion system that uses liquid nitrogen as its fuel. The proposed design captures some of the heat required for vaporizing or initial heating of the liquid nitrogen to produce electricity. The thermoelectric generator uses pressurized liquid nitrogen as its cold reservoir and ambient air as the high-temperature reservoir to generate power. This study concentrated on the selection of thermoelectric mater… more
Date: May 2007
Creator: Sivapurapu, Sai Vinay Kumar
Item Type: Refine your search to only Thesis or Dissertation
open access

Propagation analysis of a 900 MHz spread spectrum centralized traffic signal control system.

Description: The objective of this research is to investigate different propagation models to determine if specified models accurately predict received signal levels for short path 900 MHz spread spectrum radio systems. The City of Denton, Texas provided data and physical facilities used in the course of this study. The literature review indicates that propagation models have not been studied specifically for short path spread spectrum radio systems. This work should provide guidelines and be a useful ex… more
Date: May 2006
Creator: Urban, Brian L.
Item Type: Refine your search to only Thesis or Dissertation
open access

Radio frequency propagation differences through various transmissive materials.

Description: The purpose of this research was to determine which of the commonly used wireless telecommunication site concealment materials has the least effect on signal potency. The tested materials were Tuff Span® fiberglass panels manufactured by Enduro Composite Systems, Lexan® XL-1 polycarbonate plastic manufactured by GE Corporation and Styrofoam™ polystyrene board manufactured by The Dow Chemical Company. Testing was conducted in a double electrically isolated copper mesh screen room at the Univer… more
Date: December 2002
Creator: Ryan, Patrick L.
Item Type: Refine your search to only Thesis or Dissertation
open access

A Study of Laser Direct Writing for All Polymer Single Mode Passive Optical Channel Waveguide Devices

Description: The objective of this research is to investigate the use of laser direct writing to micro-pattern low loss passive optical channel waveguide devices using a new hybrid organic/inorganic polymer. Review of literature shows previous methods of optical waveguide device patterning as well as application of other non-polymer materials. System setup and design of the waveguide components are discussed. Results show that laser direct writing of the hybrid polymer produce single mode interconnects w… more
Date: May 2008
Creator: Borden, Bradley W.
Item Type: Refine your search to only Thesis or Dissertation
open access

A Study of the Synthesis and Surface Modification of UV Emitting Zinc Oxide for Bio-Medical Applications

Description: This thesis presents a novel ZnO-hydrogel based fluorescent colloidal semiconductor nanomaterial system for potential bio-medical applications such as bio-imaging, cancer detection and therapy. The preparation of ZnO nanoparticles and their surface modification to make a biocompatible material with enhanced optical properties is discussed. High quality ZnO nanoparticles with UV band edge emission are prepared using gas evaporation method. Semiconductor materials including ZnO are insoluble in w… more
Date: May 2009
Creator: John, Sween
Item Type: Refine your search to only Thesis or Dissertation
open access

Sunlight readability and luminance characteristics of light-emitting diode push button switches.

Description: Lighted push button switches and indicators serve many purposes in cockpits, shipboard applications and military ground vehicles. The quality of lighting produced by switches is vital to operators' understanding of the information displayed. Utilizing LED technology in lighted switches has challenges that can adversely affect lighting quality. Incomplete data exists to educate consumers about potential differences in LED switch performance between different manufacturers. LED switches from four… more
Date: May 2004
Creator: Fitch, Robert J.
Item Type: Refine your search to only Thesis or Dissertation
open access

Susceptibility of a digital turbine control system to IEEE 802.11 compliant emissions.

Description: Within the nuclear industry, there have been numerous instances of radio transmissions interfering with sensitive plant equipment. Instances documented vary from minor instrument fluctuations to major plant transients including reactor trips. With the nuclear power industry moving toward digital technologies for control and reactor protection systems, concern exists regarding their potential susceptibility to contemporary wireless telecommunications technologies. This study evaluates the suscep… more
Date: December 2003
Creator: Carter, Clinton E.
Item Type: Refine your search to only Thesis or Dissertation
open access

Using Motor Electrical Signature Analysis to Determine the Mechanical Condition of Vane-Axial Fans

Description: The purpose of this research was a proof of concept using a fan motor stator as transducer to monitor motor rotor and attached axial fan for mechanical motion. The proof was to determine whether bearing faults and fan imbalances could be detected in vane-axial fans using Motor Electrical Signature Analysis (MESA). The data was statistically analyzed to determine if the MESA systems could distinguish between baseline conditions and discrete fault frequencies for the three test conditions: beari… more
Date: August 2002
Creator: Doan, Donald Scott
Item Type: Refine your search to only Thesis or Dissertation
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