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Engineering Science and Materials Commons

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2009

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Articles 1 - 30 of 117

Full-Text Articles in Engineering Science and Materials

Method Of Transferring Strained Semiconductor Structure, Michael Nastasi Dec 2009

Method Of Transferring Strained Semiconductor Structure, Michael Nastasi

Mechanical & Materials Engineering Faculty Publications

The transfer of strained semiconductor layers from one substrate to another substrate involves depositing a multilayer structure on a substrate having surface contaminants. An interface that includes the contaminants if formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the deposited multilayer structure is bonded to a second substrate and is separated away at the interface, which results in transferring a multilayer structure from one substrate at least one strained semiconductor layer and at least one strain-induced seed layer. The strain-induced seed layer can be ...


Modeling And Computer Simulation Of Fault Calculations For Transmission Lines, Dr. Adel A. Elbaset Dec 2009

Modeling And Computer Simulation Of Fault Calculations For Transmission Lines, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

Calculation of transmission line faults has a fundamental importance in the fault detection, classification, and location determination of faults in transmission line. This paper presents a proposed computer program based on Matlab software to calculate all ten types of shunt faults that may occur in a transmission line. Various fault scenarios (fault types, fault locations and fault impedance) are considered in this paper. The inputs of the proposed program are line length, source voltage, positive, negative and zero sequence for source impedance, line charging, and transmission line impedance. The output of the algorithm is used to train an artificial intelligence ...


A Use Of Theory Of Constraints Thinking Processes For Improvements In The Merged Beams Experiment At Oak Ridge National Laboratory., Bryan Richard Gross Dec 2009

A Use Of Theory Of Constraints Thinking Processes For Improvements In The Merged Beams Experiment At Oak Ridge National Laboratory., Bryan Richard Gross

Electronic Theses and Dissertations

Thinking exercises used in the Theory of Constraints (TOC) were used to find and remove constraints at the Merged Beams Experiment at Oak Ridge National Laboratory. The goal of this project was to significantly reduce the amount of time used to take a certain type of measurement during an experimental cycle. After the TOC exercises were used, a basic plan for change was discovered. Preliminary data were taken to establish a baseline of performance from which changes were made. Post-Modification was analyzed showing the project was a success.

The overlying reasoning for this exercise was to prove successfully that continuous ...


Multiscale Modeling And Simulation Of Nanocrystalline Zirconium Oxide, Chaojun Wang Dec 2009

Multiscale Modeling And Simulation Of Nanocrystalline Zirconium Oxide, Chaojun Wang

Engineering Mechanics Dissertations & Theses

Nanocrystalline zirconium oxide (ZrO2) nanofibers fabricated with the sol-gel electrospinning process are expected to provide a new class of super-strong yet ultra-flexible materials. To predict their mechanical properties, we have carried out multiscale modeling and analyses. A computational model that combines the Voronoi polycrystal simulation of nanocrystalline structure with the finite element analysis has been developed. It enables the use of the first-principles predictions for the three ZrO2 crystal phases in continuum analysis of the elastic stress and strain fields in the nanofibers under uniaxial-stress tension. Calculations have been performed for each of the three phases and for ...


College Of Engineering Senior Design Competition Fall 2009, University Of Nevada, Las Vegas Dec 2009

College Of Engineering Senior Design Competition Fall 2009, University Of Nevada, Las Vegas

Senior Projects (COE)

Each student in his or her senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. The senior design project encourages the student to use everything learned in the engineering program to create a practical, real-world solution to an engineering challenge.

A highlight of the year-long senior design project is the senior design competition. This competition, which usually takes place the week before finals each semester, helps focus the senior students on increasing the quality and potential for commercial application for their design projects.

Judges from local industry evaluate the projects on innovation, commercial ...


Hydrometallurgical Process For Extraction Of Metals From Electronic Waste-Part I: Material Characterization And Process Option Selection, Zeljko J. Kamberovic Dec 2009

Hydrometallurgical Process For Extraction Of Metals From Electronic Waste-Part I: Material Characterization And Process Option Selection, Zeljko J. Kamberovic

Zeljko J Kamberovic

Used electronic equipment became one of the fastest growing waste streams in the world. In the past two decades recycling of printed circuit boards (PCBs) has been based on pyrometallurgy, higly polluting recycling technology whic causes a variety of environmental problems. The most of the contemporary research activities on recovery of base and precious metals from waste PCBs are focused on hydrometallurgical techniques as more exact, predictable and easily controlled. In this paper mechanically pretrated PCBs are leached with nitric acid. Pouring density, percentage of magnetic fraction, particle size distribution, metal content and leachability are determined using optical microscopy, atomic ...


Design, Reconstruction And Evaluation Of A Dynamometer For Quarter Scale, Samuel Sanchez Dec 2009

Design, Reconstruction And Evaluation Of A Dynamometer For Quarter Scale, Samuel Sanchez

BioResource and Agricultural Engineering

This project discusses the design, reconstruction, and evaluation of a dynamometer. A new test stand for the Quarter Scale team would improve the testing of the engines and the Continuously Variable Transmission (CVT). All the readings will be done electronically in order to provide the most accurate data collection. The dynamometer will be a closed hydraulic system for ease of use. This system will be able to test all of Quarter Scale engines. The data collected will be used to determine which engines are in the best condition, and which may need to be fixed. With the new design, the ...


Evaluation Of Fluid Diodes As Pulmonary Heart Valve Replacements, Tiffany Camp Dec 2009

Evaluation Of Fluid Diodes As Pulmonary Heart Valve Replacements, Tiffany Camp

All Dissertations

Children born with congenital heart disease often times suffer from severe chronic pulmonary insufficiency. Palliative treatments for this condition may come early on in the life of the patient; however, if it becomes severe enough, a pulmonary valve replacement may be required. There currently is not a permanent option for a replacements valve. Therefore, a need exists to develop a permanent solution. Knowing that the right heart circulation is more tolerant of moderate levels of regurgitation (0 - 35%) and pressure gradient (0 - 30 mmHg), this study investigates the hypothesis that a fluid diode, a motionless valve that offers low resistance ...


Dynamics Of Ultrasonic Consolidation, James Gibert Dec 2009

Dynamics Of Ultrasonic Consolidation, James Gibert

All Dissertations

Ultrasonic consolidation (UC) is a solid state rapid manufacturing process derived from ultrasonic welding of thin metal foils coupled with contour milling to achieve functional accurate components. The bonding of metal is accomplished by the local application of high frequency vibration energy under pressure producing a metallurgical bond without melting the base material. Its unique nature allows the design and fabrication of structural panels for satellites, production of injection molding tools, functionally graded structures, metal-matrix composites, embedded sensors, armor, and fiber embedded adaptive structures. It is commonly theorized that interfacial motion and friction at the bonding interface play a prominent ...


Linguistic Analysis Of Natural Language Engineering Requirements, Carl Lamar Dec 2009

Linguistic Analysis Of Natural Language Engineering Requirements, Carl Lamar

All Theses

In engineering design, the needs of the customer are expressed through engineering requirement statements. These requirement statements are often expressed using natural language because they are easily created and read. However, there are several problems associated with natural language requirements including but not limited to ambiguity, incompleteness, understandability, testability and over specificity. Several representation and analysis tools have been proposed to address these problems within a requirement statement. These tools include formal languages, such as UML and SysML, requirement management tools, such as IBM Telelogic Doors, and natural language processors such as QuARS. These tools assist in the systematic elicitation ...


Experimental Characterization Of Stress Relaxation In Glass, Hemanth Kadali Dec 2009

Experimental Characterization Of Stress Relaxation In Glass, Hemanth Kadali

All Theses

Glass viscoelasticity has gained importance in recent years as glass lens molding appeared as a valuable alternative to the traditional grinding and polishing process for manufacturing glass lenses. In the precision lens molding process, knowledge of viscoelastic properties of glass in the transition region, which affect the stress relaxation behavior, is required to precisely predict the final size and shape of molded lenses. The purpose of this study is to establish a step-by-step procedure for characterizing the viscoelastic behavior of glass in the glass transition region using a finite term Prony series of a Generalized Maxwell model. This study focuses ...


Vibrations Of Thin Plate With Piezoelectric Actuator: Theory And Experiments, Parikshit Mehta Dec 2009

Vibrations Of Thin Plate With Piezoelectric Actuator: Theory And Experiments, Parikshit Mehta

All Theses

Vibrations of flexible structures have been an important engineering study owing to its both deprecating and complimentary traits. These flexible structures are generally modeled as strings, bars, shafts and beams (one dimensional), membranes and plate (two dimensional) or shell (three dimensional). Structures in many engineering applications, such as building floors, aircraft wings, automobile hoods or pressure vessel end-caps, can be modeled as plates. Undesirable vibrations of any of these engineering structures can lead to catastrophic results. It is important to know the fundamental frequencies of these structures in response to simple or complex excitations or boundary conditions.
After their discovery ...


Charging Kinetics Of Electric Double Layer Capacitors, Clint Cagle Dec 2009

Charging Kinetics Of Electric Double Layer Capacitors, Clint Cagle

All Theses

A recent increase in the popularity of EDLCs and AC-EOF has necessitated a deeper understanding of the structure and charging kinetics of electrical double layers (EDLs) at electrode-electrolyte interfaces. Here, the charging kinetics of EDLs in nanoscale EDLCs is studied by a circuit model, a Poisson-Nernst-Planck (PNP) mo del, and molecular dynamics (MD) simulations. The results of the MD simulations demonstrate a linear charging behavior of EDLs near planar electrodes for both aqueous and organic electrolytes at charging below 90% and time larger than tens of picoseconds. Additionally, we will show that the circuit and PNP models are capable of ...


Design And Analysis Of Alternating Spoke Pair Concepts For A Non-Pneumatic Tire With Reduced Vibration At High Speed Rolling, Shashank Bezgam Dec 2009

Design And Analysis Of Alternating Spoke Pair Concepts For A Non-Pneumatic Tire With Reduced Vibration At High Speed Rolling, Shashank Bezgam

All Theses

Recently, Michelin has invented an innovative non-pneumatic tire which has potential for improved handling, grip, comfort, and less rolling resistance when compared to a traditional pneumatic tire. The non-pneumatic wheel is manufactured from a molding process with integrated shear ring and collapsible spokes designed to provide optimal uniform ground contact patch with low rolling resistance. The shear band is constructed from a polyurethane material with imbedded inextensible reinforcements. During high speed rolling in initial testing, the original prototype showed high noise levels at frequencies above 100 Hz. A possible source of noise could be due to vibration initiated from the ...


Robust Parameter Design And Finite Element Analysis For A Non-Pneumatic Tire With Low Vibration, Amarnath Proddaturi Dec 2009

Robust Parameter Design And Finite Element Analysis For A Non-Pneumatic Tire With Low Vibration, Amarnath Proddaturi

All Theses

During rolling of a non-pneumatic tire, vibration may be produced by the interaction of collapsible spokes with a shear deformable ring as they enter the contact region, buckle and then snap back into a state of tension. Other potential sources of vibration include the interaction of tire tread with the ground and ring vibration. In the present work, a systematic study of the effects of key geometric design parameters is presented using Taguchi's Robust Parameter Design Method and Orthogonal Arrays.
In the present work, a 2D planar finite element model with geometric non-linearity and explicit time-stepping is used to ...


Relationships Between Lane Change Performance And Open-Loop Handling Metrics, Robert Powell Dec 2009

Relationships Between Lane Change Performance And Open-Loop Handling Metrics, Robert Powell

All Theses

This work deals with the question of relating open-loop handling metrics to driver-in-the-loop performance (closed-loop). The goal is to allow manufacturers to reduce cost and time associated with vehicle handling development. A vehicle model was built in the CarSim environment using kinematics and compliance, geometrical, and flat track tire data. This model was then compared and validated to testing done at Michelin's Laurens Proving Grounds using open-loop handling metrics. The open-loop tests conducted for model validation were an understeer test and swept sine or random steer test. Four commonly used handling metrics (steady state yaw rate gain, yaw rate ...


Monitoring Co Concentration In Fuel Cells Using Microcantilever Sensors, Tugba Demir Dec 2009

Monitoring Co Concentration In Fuel Cells Using Microcantilever Sensors, Tugba Demir

All Theses

Estimating the concentration of gases including carbon monoxide (CO) in the hydrogen fuel exiting the reformer and entering the fuel cell is imperative. A high concentration of CO can cause fuel-cell catalyst poisoning, which permanently destroys the cell. Current practices call for utilizing expensive and bulky spectral analyzers to achieve this task. In addition to their high cost, these methodologies, undoubtedly, hinder the portability and self-containment of the cell. To overcome these problems and achieve the desired objectives of a portable, self-contained, and real-time measurement module, this thesis presents and experimentally investigates a new enabling technology based on utilizing an ...


Friction Stir Welding Process And Material Microstructure Evolution Modeling In 2000 And 5000 Series Of Aluminum Alloys, Harshavardhan Yalavarthy Dec 2009

Friction Stir Welding Process And Material Microstructure Evolution Modeling In 2000 And 5000 Series Of Aluminum Alloys, Harshavardhan Yalavarthy

All Theses

Interactions between the rotating and advancing pin-shaped tool (terminated at one end with a circular-cylindrical shoulder) with the clamped welding-plates and the associated material and heat transport during a Friction Stir Welding (FSW) process are studied computationally using a fully-coupled thermo-mechanical finite-element analysis. To surmount potential numerical problems associated with extensive mesh distortions/entanglement, an Arbitrary Lagrangian Eulerian (ALE) formulation was used which enabled adaptive re-meshing (to ensure the continuing presence of a high-quality mesh) while allowing full tracking of the material free surfaces. To demonstrate the utility of the present computational approach, the analysis is applied to the cases ...


Straight Line Braking Performance Of A Road Vehicle With Non Linear Tire Stiffness Formulation, Anup Khekare Dec 2009

Straight Line Braking Performance Of A Road Vehicle With Non Linear Tire Stiffness Formulation, Anup Khekare

All Theses

The capability of a road vehicle equipped with an Anti-Lock Braking System (ABS) to come to a safe stop depends on factors such as dynamic force between tire and road, surface adhesion coefficient, and the vertical profile of the road. When in panic, a driver's reaction is to step hard on the brakes to make the vehicle stop as soon as possible. Although the use of modern technologies such as ABS and Electronic Stability Control (ESC) have reduced the number of accidents significantly, any further improvement in stopping distance would only complement these technologies.
Michelin has undertaken the development ...


Identifying The Optimum Process Parameters Of Precision Glass Molding For Aspherical Lenses, Waqas Iqbal Dec 2009

Identifying The Optimum Process Parameters Of Precision Glass Molding For Aspherical Lenses, Waqas Iqbal

All Theses

The purpose of this research is to determine the optimum process parameters for the Precision Glass Molding (PGM) Process using Manufacturing Design, Design of Experiments and Metrology (for measuring the geometry of lenses). First, a custom machine is designed and manufactured which can carry out Precision Glass Lens Molding Experiments. This machine is then modified to improve temperature, position and force control. A literature review is performed to obtain data for process parameters that have been used in previous PGM studies. The collected data is then used in Design of Experiments to create twenty seven experiments that determine the optimum ...


Principal Component Thermography For Steady Thermal Perturbation Scenarios, Rohit Parvataneni Dec 2009

Principal Component Thermography For Steady Thermal Perturbation Scenarios, Rohit Parvataneni

All Theses

The work focuses on the qualitative enhancement of Thermographic Inspection data using Principal Component Analysis technique. A new processing tool named Economical Singular Value Decomposition (SVD) is proposed for analyzing the infrared image sequences acquired from the test specimen.
Experiments are carried out on test sample using thermal excitation modalities such as flash, halogen and induction to create temperature variations. The infrared (IR) image sequence containing the information about the sample is captured using IR cameras. The acquired IR image sequences are processed using the proposed Economical SVD which projects the matrix of raw pixel values of image sequence into ...


Modeling The Cooling Phase Of The Lens Molding Process, Saravanan Kannan Dec 2009

Modeling The Cooling Phase Of The Lens Molding Process, Saravanan Kannan

All Theses

The lens molding process is a relatively new technique used to manufacture lenses, in particular, high precision aspheric lenses. In order to achieve the desired size and shape of the lens, the cooling process after pressing must be controlled precisely because of the time and temperature dependent viscoelastic behavior of glass near and below the molding temperature. This thesis gives a detailed description of a three-dimensional computational model for analyzing the cooling phase of the lens molding process. Conduction, convection and radiation are considered in the model by coupling a computational fluid dynamics analysis of the flow of nitrogen through ...


User Study Of Information Extracted From Engineering Representations, Rachel Hannah Dec 2009

User Study Of Information Extracted From Engineering Representations, Rachel Hannah

All Theses

It is important for designers to understand the usefulness of different engineering representations in order to save time and money throughout a project. Designers often rely on past experience to decide which model to construct; yet students without this experience have no help. Interestingly there are noticeable gaps in the research literature with respect to how and when to select representations and modeling approaches for engineering designs. This thesis examines the differences between three types of engineering representations, specifically sketches, drawing packages, and physical prototypes. The amount of information designers can extract from these representations and also the correctness and ...


The Effect Of A Surfactant Monolayer On Gas Exchange Across An Air-Water Interface During Mixed Convection, Richard Lee Dec 2009

The Effect Of A Surfactant Monolayer On Gas Exchange Across An Air-Water Interface During Mixed Convection, Richard Lee

All Theses

A set of laboratory experiments are presented that reveal the effect of a surfactant monolayer on the transport of oxygen across an air-water interface during mixed convection conditions. The experiments were conducted in a wind/water tunnel with water tanks of differing depth. Forced convection was imposed via the air flow, while natural convection was imposed by heating the water bulk above the air temperature. For the range of wind speeds being considered, mixed convection conditions resulted. Experiments were also conducted with only forced convection present. The data acquired during these experiments were used to develop a parameterization between the ...


Wetting Behavior Of Polymer Melts With Refractory Coatings At High Temperature, Robin Woracek Dec 2009

Wetting Behavior Of Polymer Melts With Refractory Coatings At High Temperature, Robin Woracek

Masters Theses

Within the scope of this thesis, an experimental system has been designed, developed and manufactured for the determination of the wetting behavior of liquids and polymer melts with solid surfaces (coated and uncoated) at high temperatures (> 200 ºC). The measurement system incorporates a modified Wilhelmy plate technique, using a precision weighing module, a vertical linear stage, custom developed application software using LabView with suitable hardware and a high temperature furnace with thermocouple feedback control. Experiments have been performed and are reported to evaluate the performance of the testing system, using liquids of known wetting properties. A suitable testing procedure based ...


Effects On Digital Image Quality When Photographing Through A Transparent Material Used To Hold Or Flatten An Original Object, Paul E. Howell Dec 2009

Effects On Digital Image Quality When Photographing Through A Transparent Material Used To Hold Or Flatten An Original Object, Paul E. Howell

Master's Theses

An increasing number of libraries and archives are initiating projects where new and updated technologies make it practical to digitize materials containing color and fine detail. Many of the imaging systems and methods used for this process require that some type of glass or plastic be placed over the original to hold it flat and in the correct position during image capture. The physical properties of a material placed between an original object and the capture system or camera, during digitization, could possibly affect the accuracy of image color and quality being reproduced by the system. This investigation provides an ...


Relationship Between Impact Energy And Fracture Toughness Of Prestressed Concrete Railway Sleepers, Sakdirat Kaewunruen, Alexander Remennikov Sep 2009

Relationship Between Impact Energy And Fracture Toughness Of Prestressed Concrete Railway Sleepers, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering - Papers (Archive)

The prestressed concrete sleepers (or railroad ties), which are installed in railway track systems as the crosstie beam support, are designed to carry and transfer the wheel loads from the rails to the ground. It is well known that railway tracks are subject to impact loading conditions, which are attributable to the train operations with either wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration. In addition, there exists the potential of repeated load experience during the design life of prestressed concrete sleepers. Prestressed concrete has played a ...


Utilization Of Virtual Globes For Open Source Industrial Symbiosis, William Doyle, Joshua M. Pearce Sep 2009

Utilization Of Virtual Globes For Open Source Industrial Symbiosis, William Doyle, Joshua M. Pearce

Joshua M. Pearce

Several proprietary industrial symbiosis software tools have been developed, however, without long term financial commitments these endeavors fall short of creating generalizable and sustainable tools. The recent development of virtual globes such as Google Earth (GE), an information service that provides imagery and three dimensional data depicting the entire physical earth, provides an opportunity to use a new sustainable method of navigating information to save energy and use materials more efficiently in the real world. To test this open source methodology, a data set was used from the Department of Environmental Protection in Pennsylvania, which has mandated reporting the location ...


Waves In Inhomogeneous Solids, Arkadi Berezovski, Mihhail Berezovski, Juri Engelbrecht Aug 2009

Waves In Inhomogeneous Solids, Arkadi Berezovski, Mihhail Berezovski, Juri Engelbrecht

Publications

The paper aims at presenting a numerical technique used in simulating the propagation of waves in inhomogeneous elastic solids. The basic governing equations are solved by means of a finite-volume scheme that is faithful, accurate, and conservative. Furthermore, this scheme is compatible with thermodynamics through the identification of the notions of numerical fluxes (a notion from numerics) and of excess quantities (a notion from irreversible thermodynamics). A selection of one-dimensional wave propagation problems is presented, the simulation of which exploits the designed numerical scheme. This selection of exemplary problems includes (i) waves in periodic media for weakly nonlinear waves with ...


Doppler Broadening Analysis Of Steel Specimens Using Accelerator Based In Situ Pair Production, V. Makarashvili, Douglas P. Wells, Ajit K. Roy Aug 2009

Doppler Broadening Analysis Of Steel Specimens Using Accelerator Based In Situ Pair Production, V. Makarashvili, Douglas P. Wells, Ajit K. Roy

Mechanical Engineering Faculty Publications

Positron Annihilation Spectroscopy (PAS) techniques can be utilized as a sensitive probe of defects in materials. Studying these microscopic defects is very important for a number of industries in order to predict material failure or structural integrity. We have been developing gamma‐induced pair‐production techniques to produce positrons in thick samples ( ∼4–40 g/cm2, or ∼0.5–5 cm in steel). These techniques are called ‘Accelerator‐based Gamma‐induced Positron Annihilation Spectroscopy’ (AG‐PAS). We have begun testing the capabilities of this technique for imaging of defect densities in thick structural materials. As a first step, a linear ...