Search Results

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
open access

Cold-Formed Steel Bolted Connections without Washers on Oversized and Slotted Holes

Description: The use of the cold-formed steel sheet bolted connections without washers is so significant; however, the North American Specifications for the Design of Cold Formed Steel Structural Members, NASPEC, doesn't provide provisions for such connections. The bearing failure of sheet and the shear failure of sheet were considered in this study. For the sheet shear strength, it was found that the NASPEC (2007) design provisions can be used for oversized holes in both single and double shear configurati… more
Date: May 2009
Creator: Sheerah, Ibraheem
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
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.
open access

Design and Validation of an Automated Multiunit Composting System.

Description: This thesis covers the design of an automated multiunit composting system (AMUCS) that was constructed to meet the experimental apparatus requirements of the ASTM D5338 standard. The design of the AMUCS is discussed in full detail and validated with two experiments. The first experiment was used to validate the operation of the AMUCS with a 15 day experiment. During this experiment visual observations were made to visually observe degradation. Thermal properties and stability tests were perform… more
Date: December 2009
Creator: Pickens, Mark Everett
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
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.
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
open access

Effects of Minimum Quantity Lubrication in Drilling 1018 Steel.

Description: A common goal for industrial manufacturers is to create a safer working environment and reduce production costs. One common method to achieve this goal is to drastically reduce cutting fluid use in machining. Recent advances in machining technologies have made it possible to perform machining with minimum-quantity lubrication (MQL). Drilling takes a key position in the realization of MQL machining. In this study the effects of using MQL in drilling AISI 1018 steel with HSS tools using a vegetab… more
Date: December 2008
Creator: Shaikh, Vasim
open access

Electrical resistivity as a measure of change of state in substrates: Design, development and validation of a microprocessor-based system.

Description: Smart structures are relevant and significant because of their relevance to phenomena such as hazard mitigation, structural health monitoring and energy saving. Electrical resistance could potentially serve as an indicator of structural well-being or damage in the structure. To this end, the development of a microprocessor-based automated resistance measurement system with customized GUI is desired. In this research, a nodal electrical resistance acquisition circuit (NERAC) system was designed.… more
Date: December 2009
Creator: Le, Dong D.
open access

Factors influencing horizontal cracking in continuously reinforced concrete pavements (CRCP).

Description: This research presents the results on an experimental investigation to identify the significant factors influencing horizontal cracking in continuously reinforced concrete pavements (CRCP). An in-depth analysis of the microstructure, morphological characteristics of the interfacial transition zone (ITZ) and the observation of cracking using the environmental scanning electron microscope (ESEM) was done. Characterization of oxides using Fourier transform infrared spectroscopy (FTIR) and electron… more
Date: August 2008
Creator: Sudoi, Elias K.
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
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
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
open access

Hardware and Software Codesign of a JPEG2000 Watermarking Encoder

Description: Analog technology has been around for a long time. The use of analog technology is necessary since we live in an analog world. However, the transmission and storage of analog technology is more complicated and in many cases less efficient than digital technology. Digital technology, on the other hand, provides fast means to be transmitted and stored. Digital technology continues to grow and it is more widely used than ever before. However, with the advent of new technology that can reproduce d… more
Date: December 2008
Creator: Mendoza, Jose Antonio
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
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
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
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.
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.
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
open access

Micro-fabrication of a Mach-Zehnder interferometer combining laser direct writing and fountain pen micropatterning for chemical/biological sensing applications.

Description: This research lays the foundation of a highly simplified maskless micro-fabrication technique which involves incorporation of laser direct writing technique combined with fountain pen based micro-patterning method to fabricate polymer-based Mach-Zehnder interferometer sensor arrays' prototype for chemical/biological sensing applications. The research provides methodology that focuses on maskless technology, allowing the definition and modification of geometric patterns through the programming … more
Date: May 2009
Creator: Kallur, Ajay
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
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.
Back to Top of Screen