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open access

Design of a Monitoring System for a Plasma Cleaning Machine

Description: Plasma cleaning is the most effective dry process to remove surface contaminates from a SAW (Surface Acoustical Wave) device. Consistent gas pressures, flows, and good electrical connections between the chamber shelves are necessary for the process to function predictably. In addition, operation of the monitoring system must be transparent to the plasma cleaning unit. This thesis describes a simple solution to the complex problem of monitoring a plasma cleaning system. The monitoring system use… more
Date: May 1999
Creator: Fooks, Terry M. (Terry Max)
Partner: UNT Libraries

A model for designing a new telecommunication system in Mongolia

Description: The objective of this research is to design, and determine the feasibility of, a telecommunication system for the city of Erdenet, Mongolia. The Mongolian Telecommunication Company, Telecommunication Company of Erdenet city, and the National Statistical Office of Mongolia provided the data required for telecommunication forecasting of Erdenet. The literature review and analysis of the telecommunication forecasting indicate the need for a model of a new Telecommunication system in Erdenet, Mongo… more
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Date: May 2001
Creator: Baatarjav, Enkhbat
Partner: UNT Libraries
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
Partner: UNT Libraries
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
Partner: UNT Libraries
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.
Partner: UNT Libraries
open access

A Computer-Based Process Control System for a Target Station in a LINAC Facility

Description: An event-driven, sequential, process control system was designed for International Isotopes, Inc., to automate and remotely control a target station at the company's linear accelerator facility. The designed system consisted of two major sections: a software program (virtual instrument), which was developed by LabVIEW, and a hardware interface (FieldPoint Modular Distributed I/O System by National Instrument), which had to be a pre-developed system that did not require customization. The design… more
Date: May 1999
Creator: Al-Shantaf, Abdulraouf O.
Partner: UNT Libraries
open access

A Data Acquisition System Experiment for Gas Temperature and Pressure Measurements on a Liquid-Nitrogen-Powered Vehicle

Description: A data acquisition system was set up to measure gas temperatures and pressures at various points on a liquid-nitrogen-powered vehicle. The experiment was attempted to develop a data acquisition method for applications on engines that use liquid air as the fuel. Two thermocouples and a pressure transducer were connected using data acquisition instruments interfaced to a laptop computer to acquire data.
Date: May 1998
Creator: Lui, Samson Sze-Sang
Partner: UNT Libraries
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
Partner: UNT Libraries
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
Partner: UNT Libraries

Effects of Thickness and Indenter Tip Geometry in Nanoindentation of Nickel Films

Description: Nanoindentation has become a widely used technique to measure the mechanical properties of materials. Due to its capability to deform materials in micro- and nano-scale, nanoindentation has found more applications in characterizing the deformation behavior and determining the mechanical properties of thin films and coatings. This research deals with the characterization of samples received from Center for Advanced Microstructures and Devices (CAMD) and Integran Technologies Inc., Toronto, Canad… more
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Date: May 2004
Creator: Parakala, Padma
Partner: UNT Libraries

Design of Power Amplifier Test Signals with a User-Defined Multisine

Description: Cellular radio communication involves wireless transmission and reception of signals at radio frequencies (RF). Base stations house equipment critical to the transmission and reception of signals. Power amplifier (PA) is a crucial element in base station assembly. PAs are expensive, take up space and dissipate heat. Of all the elements in the base station, it is difficult to design and operate a power amplifier. New designs of power amplifiers are constantly tested. One of the most important co… more
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Date: May 2004
Creator: Nagarajan, Preeti
Partner: UNT Libraries
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.
Partner: UNT Libraries

Synthesis of cubic boron nitride thin films on silicon substrate using electron beam evaporation.

Description: Cubic boron nitride (cBN) synthesis has gained lot of interest during the past decade as it offers outstanding physical and chemical properties like high hardness, high wear resistance, and chemical inertness. Despite of their excellent properties, every application of cBN is hindered by high compressive stresses and poor adhesion. The cost of equipment is also high in almost all the techniques used so far. This thesis deals with the synthesis of cubic phase of boron nitride on Si (100) wafers … more
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Date: May 2004
Creator: Vemuri, Prasanna
Partner: UNT Libraries

Nodal Resistance Measurement System

Description: The latest development in the measurement techniques has resulted in fast improvements in the instruments used for measurement of various electrical quantities. A common problem in such instruments is the automation of acquiring, retrieving and controlling the measurements by a computer or a laptop. In this study, nodal resistance measurement (NRM) system is developed to solve the above problem. The purpose of this study is to design and develop a compact electronic board, which measures elect… more
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Date: May 2005
Creator: Putta, Sunil Kumar
Partner: UNT Libraries

Characterization of Iron Oxide Deposits Formed at Comanche Peak Steam Electric Station

Description: The presence of deposits leading to corrosion of the steam generator (SG) systems is a major contributor to operation and maintenance cost of pressurized water reactor (PWR) plants. Formation and transport of corrosion products formed due to the presence of impurities, metallic oxides and cations in the secondary side of the SG units result in formation of deposits. This research deals with the characterization of deposit samples collected from the two SG units (unit 1 and unit 2) at Comanche P… more
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Date: May 2003
Creator: Namduri, Haritha
Partner: UNT Libraries
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.
Partner: UNT Libraries
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
Partner: UNT Libraries
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.
Partner: UNT Libraries
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
Partner: UNT Libraries
open access

The Design and Development of Lightweight Composite Wall, Roof, and Floor Panels for Rigid Wall Shelter

Description: This thesis presents a research effort aimed at developing a stronger, lighter, and more economic shelter using rigid wall panels. Reported herein is insulation research, wall and roof panel design and testing, floor section modeling and strength calculations, and cost and weight calculations. Beginning stages focus on developing solid wall and roof panels using cold-formed steel corrugated sheathing and members, as well as polyurethane spray foam for insulation. This research includes calculat… more
Date: May 2018
Creator: Artman, Jeremy J
Partner: UNT Libraries
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.
Partner: UNT Libraries
open access

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

Description: This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable… more
Date: May 2017
Creator: Yata, Vishnu Vardhan Reddy
Partner: UNT Libraries
open access

Design, Modeling, and Experiment of a Piezoelectric Pressure Sensor based on a Thickness-Shear Mode Crystal Resonator

Description: This thesis presents the design, modeling, and experiment of a novel pressure sensor using a dual-mode AT-cut quartz crystal resonator with beat frequency analysis based temperature compensation technique. The proposed sensor can measure pressure and temperature simultaneously by a single AT-cut quartz resonator. Apart from AT-cut quartz crystal, a newly developed Langasite (LGS) crystal resonator is also considered in the proposed pressure sensor design, since LGS can operate in a higher tempe… more
Date: May 2017
Creator: Pham, Thanh Tuong
Partner: UNT Libraries
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
Partner: UNT Libraries
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