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2007

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Articles 1921 - 1950 of 3831

Full-Text Articles in Engineering

Compact Optical Fiber Sensor Smart Node, Seth W. Lloyd, Jason A. Newman, Daniel R. Wilding, Richard H. Selfridge, Stephen M. Schultz Mar 2007

Compact Optical Fiber Sensor Smart Node, Seth W. Lloyd, Jason A. Newman, Daniel R. Wilding, Richard H. Selfridge, Stephen M. Schultz

Faculty Publications

We present a new optical fiber sensor interrogator specifically designed for an embedded instrumentation system. The proposed system consists of a super luminescent diode as a broadband source, a high speed tunable micro-electro-mechanical system (MEMS) filter, photodetector, and an integrated microprocessor for data aggregation, processing, and communication. The entire system is integrated together in a compact package to create a fiber "smart" sensor. The system is capable of interrogating a variety of multiplexed fiber sensors, processing the data, and communicating the results digitally. As an example, the system has been calibrated with an array of fiber Bragg grating sensors

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Objective Test Methods For Waveguide Audio Synthesis, Steven Gregory Wood Mar 2007

Objective Test Methods For Waveguide Audio Synthesis, Steven Gregory Wood

Theses and Dissertations

Acoustic Physical Modeling has emerged as a newer musical synthesis technique. The most common form of physical modeling synthesis in both industry and academia is digital waveguide synthesis. Commercially available for the past thirteen years, the top synthesizer manufacturers have chosen to include physical modeling synthesis in their top of the line models. In the area of audio quality testing, the most common tests have traditionally been group listening tests. While these tests are subjective and can be expensive and time-consuming, the results are validated by the groups' proper quality standards. Research has been conducted to evaluate objective testing procedures …

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An Evaluation Of American Companies That Outsource Manufacturing To China: Decision-Making And Performance, Michael Kenyon Favreau Mar 2007

An Evaluation Of American Companies That Outsource Manufacturing To China: Decision-Making And Performance, Michael Kenyon Favreau

Theses and Dissertations

The topic of outsourcing ranks at the top of business issues for a wide variety of companies (Wery, 2004; Ezrati, 2004). The majority of American companies believe that offshore-related matters rank as the most strategic decisions that management is expected to make in the next 12 months (Wery, 2004). “Outsourcing in China can help many companies save money, but it can be very frustrating if not done right" (Ting, 2004). The perceived benefits of outsourcing production to China are tremendously enticing, but a lack of understanding of the total costs involved lures many companies into outsourcing when it is not …

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Particle Size, Gas Temperature, And Impingement Cooling Effects On High Pressure Turbine Deposition In Land Based Gas Turbines From Various Synfuels, Jared M. Crosby Mar 2007

Particle Size, Gas Temperature, And Impingement Cooling Effects On High Pressure Turbine Deposition In Land Based Gas Turbines From Various Synfuels, Jared M. Crosby

Theses and Dissertations

Four series of tests were performed in an accelerated deposition test facility to study the independent effects of particle size, gas temperature, and metal temperature on ash deposits from two candidate power turbine synfuels. The facility matches the gas temperature and velocity of modern first stage high pressure turbine vanes while accelerating the deposition process. This is done by matching the net throughput of particulate out of the combustor with that experienced by a modern power turbine. In the first series of tests, four different size particles were studied by seeding a natural-gas combustor with finely-ground coal ash particulate. The …

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Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard Mar 2007

Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard

Theses and Dissertations

Construction of tunnels and small- to medium-span bridges is a $12 billion per year industry in the United States, with a significant portion going into buried arch structures. Notwithstanding such expenditure, modern arch design and construction, in many cases, is highly conservative. This is because the closed-form solutions used by most designers today do not correctly account for soil-structure interaction. In fact, soil-structure interaction makes a closed form solution impossible. With the advent of high power computers in recent years, some designers have turned to finite element (FE)modeling as the main vehicle of analysis. Such numerical procedures provide an accurate …

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Lifetime Testing Of Wire-Grid Polarizers With Selected Over-Coatings, Steven J. Malone Mar 2007

Lifetime Testing Of Wire-Grid Polarizers With Selected Over-Coatings, Steven J. Malone

Theses and Dissertations

Wire-grid polarizers (WGPs) offer superior extinction, durability, angle of incidence, and heat resistance when compared to traditional organic polarizers. WGPs are found in applications such as high lumen lighting, laser devices, high lumen digital cinema projectors, LED packaging, and other integrated optical applications and are driving the need for over-coatings. Over-coating a WGP has been found to increase lifetime and durability. This research provides lifetime data on coated and uncoated WGPs. WGPs over-coated with 100nm of SiO2, 300nm of MgF2, and with no over-coating were heated to temperatures of 450 ºC, 500 ºC, and 550 ºC and timed until they …

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Early Age Assessment Of Cement Treated Materials, Tyler B. Young Mar 2007

Early Age Assessment Of Cement Treated Materials, Tyler B. Young

Theses and Dissertations

In order to avoid the occurrence of early-age damage, cement-treated base (CTB) materials must be allowed to cure for a period of time before the pavement can be opened to traffic. The purpose of this research was to evaluate the utility of the soil stiffness gauge (SSG), heavy Clegg impact soil tester (CIST), portable falling-weight deflectometer (PFWD), dynamic cone penetrometer, and falling-weight deflectometer for assessing early-age strength gain of cement-stabilized materials. Experimentation was performed at four sites on a pavement reconstruction project along Interstate 84 near Morgan, Utah, and three sites along Highway 91 near Richmond, Utah; cement stabilization was …

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Magnetic Annealing Of Ferromagnetic Thin Films Using Induction Heating, Paul L. Bergstrom, Melissa L. Trombley Mar 2007

Magnetic Annealing Of Ferromagnetic Thin Films Using Induction Heating, Paul L. Bergstrom, Melissa L. Trombley

Michigan Tech Patents

A method of performing magnetic annealing of a ferromagnetic thin film applied to a substrate includes applying an oscillating magnetic field to the ferromagnetic thin film to induce a current therein and heat the ferromagnetic thin film. A directional magnetic field is applied to the ferromagnetic thin film at the same time as the ferromagnetic thin film is heated, and the ferromagnetic thin film is allowed to acquire a desired magnetic characteristic, and then the oscillating magnetic field is removed and the ferromagnetic thin film is allowed to cool.

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Ceas E-News 03.20.2007, College Of Engineering And Applied Sciences Mar 2007

Ceas E-News 03.20.2007, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

Workshop focuses on bridge construction, assessment, and rehabilitation techniques

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An Investigation Of Wear-Resistant Coatings On An A390 Die-Cast Aluminum Substrate, D. Adam Mower Mar 2007

An Investigation Of Wear-Resistant Coatings On An A390 Die-Cast Aluminum Substrate, D. Adam Mower

Theses and Dissertations

In this investigation, four coatings were tested for their ability to increase the wear life of A390 aluminum primary clutch sheaves used in continuously variable transmission (CVT). The coatings tested were: hard chrome, electroless nickel metal, hard coat anodizing and composite ceramic coating. The primary clutch sheave material is a die-cast A390 aluminum. A wear test stand was developed to duplicate wear found on CVTs currently in use. The wear was evaluated using four methods. First, the change in shift characteristics of the CVT while running on the wear test stand, second a change in performance using an ATV and …

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Effects Of Spanwise And Discrete Disturbances On Separating Boundary Layers On Low Pressure Turbine Blades, Daniel D. Reimann Mar 2007

Effects Of Spanwise And Discrete Disturbances On Separating Boundary Layers On Low Pressure Turbine Blades, Daniel D. Reimann

Theses and Dissertations

Flow measurements were made on two highly loaded, low pressure turbine blade configurations in a low-speed, linear cascade facility. The L1M blade has a design Zweifel coefficient of 1.34 with a peak cp near 47% cx (mid-loaded) and the Pack B blade has a design Zweifel coefficient of 1.15 with a peak cp at 63% cx (aft-loaded). Flow velocity and surface pressure measurements were taken for Rec=20,000 and 3% inlet freestream turbulence. For these operating conditions, a large separation bubble forms on the blade suction surface, beginning at 59% cx and reattaching at 86% cx on the L1M blade and …

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Rotating Or Rotatable Compensator Spectroscopic Ellipsometer System Including Multiple Element Lenses, Blaine D. Johs, Martin M. Liphardt, Jeffrey S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, John A. Woollam Mar 2007

Rotating Or Rotatable Compensator Spectroscopic Ellipsometer System Including Multiple Element Lenses, Blaine D. Johs, Martin M. Liphardt, Jeffrey S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed are spectroscopic ellipsometer systems which include polarizer and analyzer elements which remain fixed in position during data acquisition, and at least one continuously rotating or step-wise rotatable compensator which transmits an electromagnetic beam therethrough and imposes a continuously variable or plurality of sequentially discrete polarization states on a beam of electromagnetic radiation; and at least one multiple element lens which also transmits the electromagnetic beam therethrough.

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Significant Trade Contractor Performance Characteristics As Evaluated By Big-D Construction, Conrad C. Johnson Mar 2007

Significant Trade Contractor Performance Characteristics As Evaluated By Big-D Construction, Conrad C. Johnson

Theses and Dissertations

The purpose of this research is to determine which aspects, other than price, of trade contractor performance are the most important to the general contractor, Big-D Construction. The impression a trade contractor leaves on the project manager and superintendent provides an indication of their performance. To determine what tasks trade contractors perform that most greatly impact overall perception of the general contractor's project manager and superintendent, hundreds of trade contractors were evaluated in ten separate categories and were then given an overall rating. The correlation between each category and the overall rating was found. The categories were then sorted from …

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The Effects Of Vortex Generator Jet Frequency, Duty Cycle, And Phase On Separation Bubble Dynamics, Matthew J. Bloxham Mar 2007

The Effects Of Vortex Generator Jet Frequency, Duty Cycle, And Phase On Separation Bubble Dynamics, Matthew J. Bloxham

Theses and Dissertations

Vortex generator jets (VGJs) have proven to be effective in minimizing the separation losses on low-pressure turbine blades at low Reynolds numbers. Experimental data collected using phase-locked particle image velocimetry and substantiated with a hot-film anemometer were used to answer fundamental questions about the influence of VGJs on a separated boundary layer. The data were collected on the suction surface of the Pack B blade profile, which has a non-reattaching separation bubble beginning at 68% axial chord. Two VGJ pulse histories were created with different frequencies, jet durations, and duty cycles. The mechanisms responsible for boundary layer separation control were …

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Forecasting Demand For Civilian Pilots: A Cost Savings Approach To Managing Air Force Pilot Resources, Justin W. Collup Mar 2007

Forecasting Demand For Civilian Pilots: A Cost Savings Approach To Managing Air Force Pilot Resources, Justin W. Collup

Theses and Dissertations

The purpose of this research was to create a model that could potentially predict demand for military trained pilots in the airline industry. Specifically, this thesis sought to answer the research question addressing whether or not military trained pilots are currently more in demand or less in demand. The research questions were answered through a comprehensive literature review, collection of data relevant to airline industry growth, and regression analysis. The Aviation Continuation Pay Bonus, offered to all eligible Air Force aviators, has risen from $12,000/year to its current value of $25,000/year. With shrinking budgets, and ever increasing costs of war, …

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A Layered Social And Operational Network Analysis, Jennifer L. Geffre Mar 2007

A Layered Social And Operational Network Analysis, Jennifer L. Geffre

Theses and Dissertations

To provide maximal disruption to a clandestine/terrorist network's ability to conduct missions, we must develop a means to determine the individuals' importance to the network and operations. In a network centric world, this importance is represented as an additive value of their criticality across the convergence of multiple layers of network connections. The connections layers of the network are comprised of social layers (Acquaintance, Friendship, Nuclear Family, Relatives, Student-Teacher, and Religious Mentors, Reverent Power and others), as well as layers representing interactions involving Resources, Knowledge/Skills and Temporal Local. The social criticality of an individual is measured by centrality. Event Trees …

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Modeling Dissolved Oxygen In Lake Powell Using Ce-Qual-W2, Nicholas Trevor Williams Mar 2007

Modeling Dissolved Oxygen In Lake Powell Using Ce-Qual-W2, Nicholas Trevor Williams

Theses and Dissertations

Water quality models in the Colorado River Basin have been developed for the basin, river, and individual reservoirs. They are used to support water quality programs within the basin. The models are periodically reviewed and updated to improve the accuracy of simulations. Improving the usefulness of the Lake Powell model, one of the key reservoirs in the basin, is the subject of this study. Lake Powell is simulated using a hydrodynamic and water quality model, CE-QUAL-W2. Previously the model has been used at Lake Powell to simulate hydrodynamics, temperature, and total dissolved solids with a reasonable degree of accuracy. An …

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Characterizing The Frictional Interface In Friction Stir Welding, Daryl A. Stratton Mar 2007

Characterizing The Frictional Interface In Friction Stir Welding, Daryl A. Stratton

Theses and Dissertations

Quantitative understanding of frictional phenomena between the tool and the workpiece is essential for accurate modeling of the Friction Stir Welding (FSW) process. Two methods of measuring the tool-workpiece interface are proposed that allow frictional measurements to be made under extreme conditions. The first method uses a cylindrically curved surface in contact with a flat plate. The ranges of temperature, velocity, and normal force used in this method are 100–600°C, 0.38–2.0 m/s (75–400) surface feet per minute (SFM)), and 450–2700 N (100–600 lbf), respectively. Data are gathered at different parameter level combinations to provide enough data to create an empirical …

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Rapid Runway Repair (Rrr): An Optimization For Minimum Operating Strip (Mos) Selection, David J. Duncan Mar 2007

Rapid Runway Repair (Rrr): An Optimization For Minimum Operating Strip (Mos) Selection, David J. Duncan

Theses and Dissertations

Minimum Operating Strip (MOS) selection determines the exact placement of the MOS on the damaged runway, and therefore, the amount of munitions that need to be neutralized and the amount of damage that will need to be repaired. MOS selection, in essence, is the key determinant of the time required to attain an operational takeoff and recovery surface. Since the MOS selection stage determines the events and scope of work for all of the Rapid Runway Repair (RRR) stages that follow, it could be argued that this is the most important stage in the entire RRR process. The primary purpose …

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A Multireference Density Functional Approach To The Calculation Of The Excited States Of Uranium Ions, Eric V. Beck Mar 2007

A Multireference Density Functional Approach To The Calculation Of The Excited States Of Uranium Ions, Eric V. Beck

Theses and Dissertations

An accurate and efficient hybrid Density Functional Theory (DFT)/Multireference Configuration Interaction (MRCI) model for computing electronic excitation energies in heavy element atoms and molecules was developed. This model incorporated relativistic effects essential for accurate qualitative and quantitative spectroscopic predictions on heavy elements, while simultaneously removing spin-multiplicity limitations inherent in the original model on which it is based. This model was used to successfully compute ground and low-lying electronic states for atoms in the first two rows of the period table, which were used for calibration. Once calibrated, calculations on carbon monoxide, bromine fluoride, the bromine atom, uranium +4 and +5 …

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A Multivariate Magnitude Robust Control Chart For Mean Shift Detection And Change Point Estimation, Ryan M. Harrell Mar 2007

A Multivariate Magnitude Robust Control Chart For Mean Shift Detection And Change Point Estimation, Ryan M. Harrell

Theses and Dissertations

Statistical control charts are often used to detect a change in an otherwise stable process. This process may contain several variables affecting process stability. The goal of any control chart is to detect an out-of-control state quickly and provide insight on when the process actually changed. This reduces the off-line time the quality engineer spends assigning causality. In this research, a multivariate magnitude robust chart (MMRC) was developed using a change point model and a likelihood-ratio approach. Here the process is considered in-control until one or more normally distributed process variables permanently and suddenly shifts to out-of-control, stable value. Using …

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A Qualitative Study Of Selected Quality Knowledge And Practices In Guangdong Province, China, Tyler R. Thomas Mar 2007

A Qualitative Study Of Selected Quality Knowledge And Practices In Guangdong Province, China, Tyler R. Thomas

Theses and Dissertations

The manufacturing industry has become very competitive in today's global market environment. Many US companies are faced with the choice of keeping their manufacturing domestic or looking to low cost off-shore countries to take advantage of the labor costs differences. To gain an understanding of the state of manufacturing in China, a major focus in the manufacturing world today, this thesis was undertaken. This thesis presents the findings of research conducted in Guangdong Province, China in June - July, 2005. This research addressed customer focus, leadership and general manufacturing and quality knowledge and practices of small, medium and large sized …

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Decision Analysis With Value Focused Thinking As A Methodology To Select Building For Deconstruction, Erika E. Maiorano Mar 2007

Decision Analysis With Value Focused Thinking As A Methodology To Select Building For Deconstruction, Erika E. Maiorano

Theses and Dissertations

The purpose of this research was to examine the reuse and recycling of building materials on Wright-Patterson Air Force Base. There are a variety of conflicting factors concerning the removal of a building and the model quantitatively evaluates alternatives with respect to the decision maker’s values. The research questions were addressed with both a comprehensive literature review as well as the implementation of the value focused thinking methodology. The model found that the temporary living facilities are the alternatives that achieve the highest value. The result of this research effort was a value model that aids decision makers in identifying …

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Development Of An Experimental Platform For Testing Autonomous Uav Guidance And Control Algorithms, Justin R. Rufa Mar 2007

Development Of An Experimental Platform For Testing Autonomous Uav Guidance And Control Algorithms, Justin R. Rufa

Theses and Dissertations

With the United States' push towards using unmanned aerial vehicles (UAVs) for more military missions, wide area search theory is being researched to determine the viability of multiple vehicle autonomous searches over the battle area. Previous work includes theoretical development of detection and attack probabilities while taking into account known enemy presence within the search environment. Simulations have been able to transform these theories into code to predict the UAV performance against known numbers of true and false targets. The next step to transitioning these autonomous search algorithms to an operational environment is the experimental testing of these theories through …

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Calibration Procedure For A Microscopic Traffic Simulation Model, Carole Turley Mar 2007

Calibration Procedure For A Microscopic Traffic Simulation Model, Carole Turley

Theses and Dissertations

The inputs to a microscopic traffic simulation model generally include quantitative, but immeasurable data describing driver behavior and vehicle performance characteristics. Engineers often use default values for parameters such as car-following sensitivity and gap acceptance because it can be difficult to obtain accurate estimates for these parameters. While recent research has indicated that the accuracy of a simulation model can significantly improve if driver behavior parameters are calibrated to local data, this is not a typical practice. Manual calibration of these parameters is often too time-consuming to be cost-effective. Researchers have applied automated calibration procedures using genetic algorithms to these …

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On-Chip Atomic Spectroscopy, Donald B. Conkey Mar 2007

On-Chip Atomic Spectroscopy, Donald B. Conkey

Theses and Dissertations

This thesis presents the integration of atomic vapor cells with anti-resonant reflecting optical waveguides (ARROWs) fabricated on silicon chips. These potentially provide a compact platform for a number of optical applications, including the study of quantum coherence effects such as electromagnetically induced transparency and single-photon nonlinearities, as well as frequency stabilization standards. The use of hollow waveguides allows for light propagation in low index (vapor) media with compact mode areas. ARROWs make particularly attractive waveguides for this purpose because they can be interfaced with solid core waveguides, microfabricated on a planar substrate, and are effectively single mode. ARROW fabrication utilizes …

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Semi Autonomous Vehicle Intelligence: Real Time Target Tracking For Vision Guided Autonomous Vehicles, Jonathan D. Anderson Mar 2007

Semi Autonomous Vehicle Intelligence: Real Time Target Tracking For Vision Guided Autonomous Vehicles, Jonathan D. Anderson

Theses and Dissertations

Unmanned vehicles (UVs) are seeing more widespread use in military, scientific, and civil sectors in recent years. These UVs range from unmanned air and ground vehicles to surface and underwater vehicles. Each of these different UVs has its own inherent strengths and weaknesses, from payload to freedom of movement. Research in this field is growing primarily because of the National Defense Act of 2001 mandating that one-third of all military vehicles be unmanned by 2015. Research using small UVs, in particular, is a growing because small UVs can go places that may be too dangerous for humans. Because of the …

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Internet Protocol Geolocation: Development Of A Delay-Based Hybrid Methodology For Locating The Geographic Location Of A Network Node, John M. Roehl Mar 2007

Internet Protocol Geolocation: Development Of A Delay-Based Hybrid Methodology For Locating The Geographic Location Of A Network Node, John M. Roehl

Theses and Dissertations

Internet Protocol Geolocation (IP Geolocation), the process of determining the approximate geographic location of an IP addressable node, has proven useful in a wide variety of commercial applications. Commercial applications of IP Geolocation include market research, redirection for performance enhancement, restricting content, and combating fraud. The potential for military applications include securing remote access via geographic authentication, intelligence collection, and cyber attack attribution. IP Geolocation methods can be divided into three basic categories based upon what information is used to determine the geographic location of the given IP address: 1) Information contained in databases, 2) information that is leaked during …

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Wide Area Search And Engagement Simulation Validation, Michael J. Marlin Mar 2007

Wide Area Search And Engagement Simulation Validation, Michael J. Marlin

Theses and Dissertations

As unmanned aerial vehicles (UAVs) increase in capability, the ability to refuel them in the air is becoming more critical. Aerial refueling will extend the range, shorten the response times, and extend loiter time of UAVs. Executing aerial refueling autonomously will reduce the command and control, logistics, and training efforts associated with fielding UAV systems. Currently, the Air Force Research Lab is researching the various technologies required to conduct automated aerial refueling (AAR). One of the required technologies is the ability to autonomously rendezvous with the tanker. The goal of this research is to determine the control required to fly …

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Active Control Of A Thin Deformable In-Plane Actuated Mirror, Thomas P. Gabriele Jr. Mar 2007

Active Control Of A Thin Deformable In-Plane Actuated Mirror, Thomas P. Gabriele Jr.

Theses and Dissertations

The constitutive relations traditionally used for finding shear stress and heat flux in a fluid become invalid in non-equilibrium flow. Their derivation from kinetic theory only demonstrates they are valid only for small deviations from equilibrium. Because it is fundamentally linked to non-equilibrium, entropy generation is used to investigate the limits of the continuum constitutive relations. However, the continuum equations are inherently limited to near equilibrium conditions due to the constitutive relations; thus kinetic theory must be used as a basis for comparison. Direct Simulation Monte Carlo (DSMC), a particle method alternative to continuum methods, is based on kinetic theory …

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