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2003

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Full-Text Articles in Engineering Science and Materials

Directional Solidification, Microstructures And Mechanical Properties Of Cr-Cr3si Eutectic Alloys, Hongbin Bei Dec 2003

Directional Solidification, Microstructures And Mechanical Properties Of Cr-Cr3si Eutectic Alloys, Hongbin Bei

Doctoral Dissertations

Alloys based on intermetallics have been considered for high temperature structural applications. However, many of these alloys suffer from intrinsic brittleness and low fracture toughness at ambient temperature. Therefore, ductile-phase-toughened intermetallic composites are being investigated as a means to improve the fracture toughness. A subset of this class of materials is in-situ composites produced by directional solidification of intermetallic eutectics. In this study, the Cr-Cr3Si eutectic system is selected as a model system to investigate composites by directional solidification, where the strong, but brittle Cr3Si is combined with a more ductile Cr-rich solid solution.

A series ...


Numerical Simulation Of Separating Flows Using Computational Models Based On The Vorticity Confinement Method, Lesong Wang Dec 2003

Numerical Simulation Of Separating Flows Using Computational Models Based On The Vorticity Confinement Method, Lesong Wang

Doctoral Dissertations

The objective of the present research is to investigate the recent development of the vorticity confinement method. First, a new formulation of the vorticity confinement term is studied. Advantages of the new formulation over the original one include the ability to conserve the momentum, and the ability to preserve the centroid motion of some flow properties such as the vorticity magnitude. Next, new difference schemes, which are simpler and more efficient than the old schemes, are discussed. At last, two computational models based on the vorticity confinement method are investigated. One of the models is devised to simulate inviscid flows ...


Chemical Kinetics And Thermal Hydraulics Of Lead Bismuth Flow Loops, Kanthi Kiran Dasika Dec 2003

Chemical Kinetics And Thermal Hydraulics Of Lead Bismuth Flow Loops, Kanthi Kiran Dasika

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of the thesis is to study the effect of chemical kinetics and thermal hydraulics of Lead Bismuth Eutectic (LBE) flow in the Materials Test Loop (MTL). The Materials Test Loop, also known as the Delta Loop, was built in Los Alamos National Laboratories (LANL) to obtain the experimental data for corrosion estimation and analysis. It is a well-known fact that corrosion plays an important role in the design of nuclear thermal hydraulic systems. Since the MTL is a multi-section closed system that differs in diameter from one part to another, an intensive study on the overall and regional ...


Effect Of Loading Frequency On Intervertebral Disc Cells., Kristen Nicole Loveless Dec 2003

Effect Of Loading Frequency On Intervertebral Disc Cells., Kristen Nicole Loveless

Masters Theses

Cells of the intervertebral disc have a limited capacity for matrix repair and may contribute to the onset and progression of degenerative disc changes. Disc degeneration contributes to declining nutrition, loss of viable cells, cell senescence, post-translational modification of matrix proteins, accumulation of degraded matrix molecules, and fatigue failure of the matrix. During daily activities intervertebral discs are exposed to oscillatory hydrostatic loads. It is known that dynamic loads with critical frequencies close to that of the human spine resonant frequency (4-8 Hz) have a destructive effect on disc tissue properties. Whether this destructive effect is purely mechanical due to ...


Modeling Of Circulation Zone And Shear Layers In Coaxial Injectors, Clayton Andrew White Dec 2003

Modeling Of Circulation Zone And Shear Layers In Coaxial Injectors, Clayton Andrew White

Masters Theses

Gaseous/gaseous hydrogen oxygen shear coaxial injectors were modeled to investigate grid parameters affecting solution and to determine if a steady state solution might exist if only one circulation zone was present. The General Equation Mesh Solver (GEMS), which implements the Reynolds Averaged Navier-Stokes equations with the k-ω turbulence model, was used to conduct the study. The Gambit grid generator was used to construct computational grids. Different grids were compared in a search for the optimum configuration while residual levels were monitored in search of a steady state solution.


Remote Monitoring Of Repository Integrity Using Passive Seismic Arrays, Barbara Luke, Evangelos Yfantis Sep 2003

Remote Monitoring Of Repository Integrity Using Passive Seismic Arrays, Barbara Luke, Evangelos Yfantis

Publications (YM)

Once radioactive waste is emplaced in the repository, the challenge of monitoring the continued integrity of the excavated openings (e.g., emplacement drifts) escalates tremendously. We envision a seismic monitoring array installed on the surface at Yucca Mountain, which operates automatically to monitor repository opening stability in the long term. The objective is to monitor and validate the structural integrity of the emplacement drifts through identifying and localizing rock falls that could compromise drift access, hinder waste retrievability, and potentially reduce the effective life of waste canisters. Collateral benefits of the system include the ability to address some outstanding uncertainties ...


The Development And Verification Of Three Matlab Analysis Applications Programmed Specifically For Engage Team Projects., Jonathan W. Huber Aug 2003

The Development And Verification Of Three Matlab Analysis Applications Programmed Specifically For Engage Team Projects., Jonathan W. Huber

Masters Theses

This thesis outlines the development of three analysis applications for use in the freshmen Engineering Fundamentals Program (engage) at the University of Tennessee. Engage teaches freshmen engineering mechanics concepts through a set of integrated components including Lecture, Analysis and Skills, Problem Session, Physical Homework, and Team Projects. Presently, the students have limited access to any software analysis tools to aid the design process. The students have little experience writing the types of complex programs needed to analyze a particular project. Even more, they do not have the time. The applications provide a means for the students to perform an accurate ...


A Study On The Prediction Of Viscosity With The Use Of Numerical Simulation Software, Brian Robinson Aug 2003

A Study On The Prediction Of Viscosity With The Use Of Numerical Simulation Software, Brian Robinson

Masters Theses

A study was undertaken to numerically simulate the flow of highly viscous fluid. Simulating a highly viscous flow within a parallel plate plastometer will hopefully begin to bridge the gaps in the current knowledge of these viscous models. The modeling of this flow was performed using the canned code FiDAP from Fluent Inc. The results are compared with the analytical results calculated by NASA Marshall researchers.


Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu Jul 2003

Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Corrosion is an extremely important issue in nuclear cooling system applications. Many scientific and engineering efforts have been contributed to the research of finding an ideal material, which has resistance to corrosive Lead Bismuth Eutectic (LBE). A Delta Loop was designed and constructed in Los Alamos National Lab (LANL) to obtain the experimental data. This loop is a multi-section closed system that differs in diameter from one part to another. As a result, an intensive study on the geometry effect is hence necessary and valuable. In this thesis, this problem was simulated by commercial software STAR-CD. Results provide a good ...


Optically Transparent, Scratch-Resistant, Diamond-Like Carbon Coatings, Xiao-Ming He, Deok-Hyung Lee, Michael A. Nastasi, Kevin C. Walter, Michel G. Tuszewski Jun 2003

Optically Transparent, Scratch-Resistant, Diamond-Like Carbon Coatings, Xiao-Ming He, Deok-Hyung Lee, Michael A. Nastasi, Kevin C. Walter, Michel G. Tuszewski

Mechanical & Materials Engineering Faculty Publications

A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleble to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit abherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced ...


Method For Producing Fluorinated Damond-Like Carbon Films, Marko J. Hakovirta, Michael Nastasi, Deok-Hyung Lee, Xiao-Ming He Jun 2003

Method For Producing Fluorinated Damond-Like Carbon Films, Marko J. Hakovirta, Michael Nastasi, Deok-Hyung Lee, Xiao-Ming He

Mechanical & Materials Engineering Faculty Publications

Fluorinated, diamond-like carbon (F-DLC) films are produced by a pulsed, glow-discharge plasma immersion ion processing procedure. The pulsed, glow-discharge plasma was generated at a pressure of 1 Pa from an acetylene (CH) and hexafluoroethane (CF) gas mixture, and the fluorinated, diamond-like carbon films were deposited on silicon <100>Substrates. The film hardness and wear resistance were found to be strongly dependent on the fluorine content incorporated into the coatings. The hardness of the F-DLC films was found to decrease considerably when the fluorine content in the coatings reached about 20%. The contact angle of water on the F-DLC coatings was found ...


Quelques Conseils À Nos Nouveau Diplomés, Fathi Habashi Jun 2003

Quelques Conseils À Nos Nouveau Diplomés, Fathi Habashi

Fathi Habashi

An advice, the old wise man Polonius offered to the young Hamlet was “Neither a borrower, nor a lender be”, may be no longer pertinent. Some more relevant advices are offered to new graduates of the twentieth century. Available in English, French, and Spanish


Abstracts, Review Of Progress In Quantitative Nondestructive Evaluation (Green Bay, Wi, July 27–August 1, 2003), Center For Nondestructive Evaluation, Iowa State University May 2003

Abstracts, Review Of Progress In Quantitative Nondestructive Evaluation (Green Bay, Wi, July 27–August 1, 2003), Center For Nondestructive Evaluation, Iowa State University

Review of Progress in Quantitative Nondestructive Evaluation

Abstracts of papers presented at the 2003 Review of Progress in Quantitative Nondestructive Evaluation (QNDE) conference, held in Green Bay, Wisconsin from July 27–August 1, 2003.


A Study Of The Electron Beam Scattering Under Various Gaseous Environment, Jing He May 2003

A Study Of The Electron Beam Scattering Under Various Gaseous Environment, Jing He

Masters Theses

There are three objectives in this work: to experimentally measure the profiles of electron beams scattered by interaction with a gas, to measure total scattering cross-sections for gases and to apply the cross-section data in a suitable Monte Carlo simulation to predict beam scattering profiles for comparison with experiment.
The experimentally measured profiles cover a wide range of intensity variation. There are two evidenced regions: an inner region and an outer skirt corresponding to inelastic (small angle) and elastic scattering respectively are appeared. These profiles use the planar p-n junction gives us an overall look at the electron beam spreading ...


Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann May 2003

Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann

Electrical & Computer Engineering Faculty Publications

The evolution of the band structure of β-In2 S3−3x O3x (BISO) thin films grown by physical vapor deposition, with composition x, is investigated using x-ray photoelectron spectroscopy. It is shown that the energy difference between the valence-band level and the Fermi level remains nearly constant as the optical band gap of the films increases. As a consequence, the difference between the conduction band level and the Fermi level increases as much as the optical band gap of the films. The calculation of the electronic affinity [ ] of the BISO thin films shows that it decreases linearly from 4.65 to ...


Fuzzy System Identification Based Upon A Novel Approach To Nonlinear Optimization, Raymond Scott Starsman Apr 2003

Fuzzy System Identification Based Upon A Novel Approach To Nonlinear Optimization, Raymond Scott Starsman

Electrical & Computer Engineering Theses & Disssertations

Fuzzy systems are often used to model the behavior of nonlinear dynamical systems in process control industries because the model is linguistic in nature, uses a natural-language rule set, and because they can be included in control laws that meet the design goals. However, because the rigorous study of fuzzy logic is relatively recent, there is a shortage of well-defined and understood mechanisms for the design of a fuzzy system. One of the greatest challenges in fuzzy modeling is to determine a suitable structure, parameters, and rules that minimize an appropriately chosen error between the fuzzy system, a mathematical model ...


On The Physicochemical Problems Of Aqueous Oxidation Of Polymetallic Gold Bearing Sulphide Ore In An Autoclave, Zeljko J. Kamberovic Jan 2003

On The Physicochemical Problems Of Aqueous Oxidation Of Polymetallic Gold Bearing Sulphide Ore In An Autoclave, Zeljko J. Kamberovic

Zeljko J Kamberovic

The paper presents a study on the physical and chemical changes of iron, copper and zinc sulphide minerals in process of pressure oxidation. Oxidation in autoclave is a pre-treatment unit operation for refractory sulphide ores and concentrates in order to valorisat gold, which is encapsuled mainly in pyrite matrix. Raw materials and solid residues are charasterisated. Basing on the results of chemical reactions and on shape of solids residue, we came to a conclusion concerning the mechanism of oxidation in autoclave. The results show that modelling of the process parameters of oxidation in autoclave can be used to predict efficiency ...


Leaching Of Copper(I) Sulphide By Sulphuric Acid Solution With Addition Of Sodium Nitrate, Zeljko J. Kamberovic Jan 2003

Leaching Of Copper(I) Sulphide By Sulphuric Acid Solution With Addition Of Sodium Nitrate, Zeljko J. Kamberovic

Zeljko J Kamberovic

Finely grained samples of copper(I) sulphide were leached by H2SO4 solution with added NaNO3. The occurrence probability of chemical reactions was analysed based on literature data and products which were formed during the process and the overall leaching reaction was defined. The effect of temperature, concentration of NaNO3 and H2SO4, stirring speed, phase ratio and time, on the leaching degree of copper was studied. The quantity of copper dissolved increases with growth of the values of all the parameters. Kinetic analysis shows that the leaching mechanism is very complex. By using appropriate mathematical kinetic models, it is found that ...


From Alchemy To Atomic Bombs. Book Review By George Kauffman, Fathi Habashi Jan 2003

From Alchemy To Atomic Bombs. Book Review By George Kauffman, Fathi Habashi

Fathi Habashi

Review of the book "From Alchemy to Atomic Bombs" by Fathi Habashi published by Métallurgie Extractive Québec. The review is written by Professor George Kauffman at California State University, Fresno.


High Strain Rate Properties Of Polymer Matrix Composites, Amol Jadhav Jan 2003

High Strain Rate Properties Of Polymer Matrix Composites, Amol Jadhav

LSU Master's Theses

The vast differences in strength, ultimate strain and modulus during high strain rate (HSR) deformation of materials have been a very long-standing subject of engineering interest. This thesis deals with characterization of mechanical properties of two composite materials, balanced angle-ply graphite epoxy laminates (fibrous composite) and syntactic foams (particulate composite). The focus of this study is to compare the mechanical properties of these composite materials at high strain rates and quasi-static conditions and to find out the effects of failure modes on HSR mechanical properties of these materials. Split Hopkinson Pressure Bar (SHPB) apparatus is used for the HSR testing ...


Alloy States In Dilute Gaas1-XNX Alloys (X<1%), X. D. Luo, Jinsong Huang, Z. Y. Xu, C. L. Yang, J. Liu, W. K. Ge, Y. Zhang, A. Mascarenhas, H. P. Xin, C. W. Tu Jan 2003

Alloy States In Dilute Gaas1-XNX Alloys (X<1%), X. D. Luo, Jinsong Huang, Z. Y. Xu, C. L. Yang, J. Liu, W. K. Ge, Y. Zhang, A. Mascarenhas, H. P. Xin, C. W. Tu

Mechanical & Materials Engineering Faculty Publications

A set of GaAs1-xNx samples with small nitrogen composition (x<1%) were investigated by continuous-wave photoluminescence (PL), pulse-wave excitation PL, and time-resolved PL. In the PL spectra, an extra transition located at the higher-energy side of the commonly reported N-related emissions was observed. By measuring the PL dependence on temperature and excitation power, the PL peak was identified as a transition of alloy band edge-related recombination in GaAsN. The PL dynamics further confirms its intrinsic nature as being associated with the band edge rather than N-related bound states.


Air-Coupled Ultrasonic Measurements In Composites, Vamshi K.R. Kommareddy Jan 2003

Air-Coupled Ultrasonic Measurements In Composites, Vamshi K.R. Kommareddy

Retrospective Theses and Dissertations

Air-coupled ultrasound is a non-contact technique and has clear advantages over water-coupled testing. This work aims at gaining quantitative understanding of the principles underlining air-coupled ultrasonic measurement. The beams of air transducers, with and without Apodization, were mapped out. The transmission of air-coupled ultrasonic energy through a plate is measured experimentally; model calculation of the transmission coefficient, taking into account the real transducer characteristics, is compared with the experimental results. The occurrence of "Poisson bright spot" in the flaw images of thin laminates and honeycomb composites were investigated; A qualitative comparison with a model based on the Fresnel's wave ...


Study Of A Growth Instability Of Γ-In[Sub 2]Se[Sub 3], C. Amory, J. C. Bernede, S. Marsillac Jan 2003

Study Of A Growth Instability Of Γ-In[Sub 2]Se[Sub 3], C. Amory, J. C. Bernede, S. Marsillac

Electrical & Computer Engineering Faculty Publications

γ-In[sub 2]Se[sub 3] thin film are deposited for various substrate temperatures in the range of 523–673 K. This study shows that at 573 and 673 K the thin films are well crystallized with grains aligned along the c axis. Between these temperatures, a domain of instability appears where the γ-In[sub 2]Se[sub 3] thin films have a randomly orientation and the c-lattice parameter increases. The presence of the metastable phase κ-In[sub 2]Se[sub 3], during the growth, can explain the existence of this domain of instability. The insertion of Zn during the ...


Freeway Accident Analysis Using Second Order Statistics, Khasim Khasimul Shaik Jan 2003

Freeway Accident Analysis Using Second Order Statistics, Khasim Khasimul Shaik

LSU Master's Theses

This research focuses on the use of historical freeway traffic data for comparison of the precursory traffic conditions to that accident occurrence by using 15-minute traffic speed contour maps. The second order statistics measures, namely angular second moment (ASM), contrast and entropy were used as the traffic performance measures in order to compare the two situations. The data used is from I-4 freeway traffic condition database, stored in a SQL server and 1999 year accident database for the same I-4 freeway. The study section is located in Orlando, Florida. The approach shows an approach to understand the performance of the ...


Progressive Fatigue Effects On Manual Lifting Factors, Anthony D'Wayne Banks Jan 2003

Progressive Fatigue Effects On Manual Lifting Factors, Anthony D'Wayne Banks

LSU Doctoral Dissertations

Much evidence suggests that the cause of lower back pain (LBP) and injury is frequently related to the posture of lifting, the load, muscle fatigue, and other factors. The purpose of this study was to evaluate the effect of progressive fatigue on factors that have previously been associated with increased risk of LBP in various occupational settings, during a repetitive lifting task where freestyle lifting technique was utilized. A laboratory experiment was conducted to evaluate several fatigue analysis, electromyography amplitude, kinematic, and kinetic parameters of repetitive freestyle lifting during a 2-hour lifting period. Each of ten (10) young adult male ...


Characterization Of Syntactic Foams And Their Sandwich Composites: Modeling And Experimental Approaches, Nikhil Gupta Jan 2003

Characterization Of Syntactic Foams And Their Sandwich Composites: Modeling And Experimental Approaches, Nikhil Gupta

LSU Doctoral Dissertations

Hollow particle filled polymers known as syntactic foams are lightweight and highly damage tolerant. Syntactic foams are used as core materials in sandwich composites. The use of such materials in aeronautical and space structures make it necessary to understand their characteristics for various environmental and loading conditions. The first part of the present work takes modeling and finite element analysis approach to understand and predict the deformation behavior of syntactic foams. Contact analysis is performed on single particle models by the finite element analysis approach. In the second part extensive experiments are carried out to characterize syntactic foams for hygrothermal ...


Optimization And Automation Of A Thermal Oyster Shucking Process, Daniel Edgar Martin Jan 2003

Optimization And Automation Of A Thermal Oyster Shucking Process, Daniel Edgar Martin

LSU Doctoral Dissertations

Louisiana Gulf Coast oysters (Crassostrea virginica) were subjected to thermal shucking treatments to effect adductor muscle release from both left and right valves. The oysters were instrumented with thermocouples to monitor and record process temperatures in the oysters and on the shell. Following treatment, the oysters were evaluated for relaxation and release of the adductor muscle, meat quality and texture, and for the effect of the treatments on the storage life of the oysters as measured by total microbial plate counts. The treatments of many oysters resulted in a complete release of the adductor muscle from the shell while maintaining ...


Finite-Horizon Operations Planning For A Lean Supply Chain System, Ahmad Diponegoro Jan 2003

Finite-Horizon Operations Planning For A Lean Supply Chain System, Ahmad Diponegoro

LSU Doctoral Dissertations

This dissertation studies an operational policy for a lean supply chain system consisting of a manufacturer, multiple suppliers and multiple buyers. The manufacturer procures raw materials from the suppliers and converts them into finished products, which are then shipped in batches to the buyers at certain intervals of times. Three distinct but inseparable problems are addressed: single supplier and single buyer with fixed delivery size (FD), multiple suppliers and multiple buyers with individual delivery schedule (MD), and time dependent delivery quantity with trend demand (TD). The mathematical formulations of these supply systems are categorized as mixed-integer, nonlinear programming problems (MINLAP ...


Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta Jan 2003

Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta

LSU Master's Theses

Diamondlike carbon (DLC) films have been explored extensively in the past due to their highly attractive properties. However, the high level of internal stress developed during growth prevents deposition of thick films. Synthesis of DLC/DLC multilayers (DDM) presents a venue to overcome this drawback. In the present study, DLC films and DDM were deposited on Si substrate using dc plasma of CH4 and Ar gas mixture. FTIR was used to analyze the structure of the DLC films. Mechanical properties of the films were characterized by microhardness testing and nanoindentation. The tribological properties were studied by conducting pin-on-disc experiments ...


Rotary Kiln Incineration Of Hazardous Wastes: Pilot-Scale Studies At Louisiana State University, John Sutherland Earle Jan 2003

Rotary Kiln Incineration Of Hazardous Wastes: Pilot-Scale Studies At Louisiana State University, John Sutherland Earle

LSU Doctoral Dissertations

Studies of incineration of surrogates for hazardous wastes are conducted in the pilot-scale rotary kiln incinerator (RKI) at Louisiana State University (LSU) in Baton Rouge, Louisiana. The purpose of the research is to investigate methods of treating and destroying hazardous wastes in a cost-effective and environmentally sound way. The objective is to provide process data that will contribute to increased knowledge for RKI design and operation. The LSU facility is a College of Engineering Combustion Laboratory that is unique in its large size as a university laboratory. It is equipped with individual instruments for analysis of O2, CO, CO ...