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Articles 1591 - 1620 of 4566

Full-Text Articles in Engineering

Meshless Direct Numerical Simulation Of Turbulent Incompressible Flows, Andres Vidal Urbina Jan 2015

Meshless Direct Numerical Simulation Of Turbulent Incompressible Flows, Andres Vidal Urbina

Electronic Theses and Dissertations

A meshless direct pressure-velocity coupling procedure is presented to perform Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of turbulent incompressible flows in regular and irregular geometries. The proposed method is a combination of several efficient techniques found in different Computational Fluid Dynamic (CFD) procedures and it is a major improvement of the algorithm published in 2007 by this author. This new procedure has very low numerical diffusion and some preliminary calculations with 2D steady state flows show that viscous effects become negligible faster that ever predicted numerically. The fundamental idea of this proposal lays on several important inconsistencies …

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An Improved Biosolid Gasifier Model, Hannah Mclean Jan 2015

An Improved Biosolid Gasifier Model, Hannah Mclean

Electronic Theses and Dissertations

As populations increase and cities become denser, the production of waste, both sewage sludge and food biomass, increases exponentially while disposal options for these wastes are limited. Landfills have minimal space for biosolids; countries are now banning ocean disposal methods for fear of the negative environmental impacts. Agricultural application of biosolids cannot keep up with the production rates because of the accumulation of heavy metals in the soils. Gasification can convert biosolids into a renewable energy source that can reduce the amount of waste heading to the landfills and reduce our dependence on fossil fuels. A recently published chemical kinetic …

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Predictive Modeling For Assessing The Reliability Of Bypass Diodes In Photovoltaic Modules, Narendra Shiradkar Jan 2015

Predictive Modeling For Assessing The Reliability Of Bypass Diodes In Photovoltaic Modules, Narendra Shiradkar

Electronic Theses and Dissertations

Solar Photovoltaics (PV) is one of the most promising renewable energy technologies for mitigating the effect of climate change. Reliability of PV modules directly impacts the Levelized Cost of Energy (LCOE), which is a metric for cost competitiveness of any energy technology. Further reduction in LCOE of PV through assured long term reliability is necessary in order to facilitate widespread use of solar energy without the need for subsidies. This dissertation is focused on frameworks for assessing reliability of bypass diodes in PV modules. Bypass diodes are critical components in PV modules that provide protection against shading. Failure of bypass …

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A Roughness Correction For Aquarius Ocean Brightness Temperature Using The Conae Microwave Radiometer, Yazan Hejazin Jan 2015

A Roughness Correction For Aquarius Ocean Brightness Temperature Using The Conae Microwave Radiometer, Yazan Hejazin

Electronic Theses and Dissertations

Aquarius/SAC-D is a joint NASA/CONAE (Argentine Space Agency) Earth Sciences satellite mission to measure global sea surface salinity (SSS), using an L-band radiometer that measures ocean brightness temperature (Tb). The application of L-band radiometry to retrieve SSS is a difficult task, and therefore, precise Tb corrections are necessary to obtain accurate measurements. One of the major error sources is the effect of ocean roughness that "warms" the ocean Tb. The Aquarius (AQ) instrument (L-band radiometer/scatterometer) baseline approach uses the radar scatterometer to provide this ocean roughness correction, through the correlation of radar backscatter with the excess ocean emissivity. In contrast, …

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Modified System Design And Implementation Of An Intelligent Assistive Robotic Manipulator, Nicholas Paperno Jan 2015

Modified System Design And Implementation Of An Intelligent Assistive Robotic Manipulator, Nicholas Paperno

Electronic Theses and Dissertations

This thesis presents three improvements to the current UCF MANUS systems. The first improvement modifies the existing fine motion controller into PI controller that has been optimized to prevent the object from leaving the view of the cameras used for visual servoing. This is achieved by adding a weight matrix to the proportional part of the controller that is constrained by an artificial ROI. When the feature points being used are approaching the boundaries of the ROI, the optimized controller weights are calculated using quadratic programming and added to the nominal proportional gain portion of the controller. The second improvement …

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Investigating Simulation-Based Pattern Recognition Training For Behavior Cue Detection, Crystal Maraj Jan 2015

Investigating Simulation-Based Pattern Recognition Training For Behavior Cue Detection, Crystal Maraj

Electronic Theses and Dissertations

The U.S. military uses pattern recognition training to observe anomalies in human behavior. An examination of the pattern recognition training literature for Warfighters reveals a gap in training to discern patterns of human behavior in live environments. Additionally, the current state of warfare is evolving and requires operations to change. As a result, pattern recognition training must accommodate new practices to improve performance. A technique used to improve memory for identifying patterns in the environment is Kim's game. Kim's game establishes patterns to identify inanimate objects, of which information retains in memory for later recall. The paper discusses the fundamental …

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A Multi-Scale Cfd Analysis Of Patient-Specific Geometries To Tailor Lvad Cannula Implantation Under Pulsatile Flow Conditions: An Investigation Aimed At Reducing Stroke Incidence In Lvads, Ray Prather Jan 2015

A Multi-Scale Cfd Analysis Of Patient-Specific Geometries To Tailor Lvad Cannula Implantation Under Pulsatile Flow Conditions: An Investigation Aimed At Reducing Stroke Incidence In Lvads, Ray Prather

Electronic Theses and Dissertations

A Left Ventricular Assist Device (LVAD) is a mechanical pump that provides temporary circulatory support when used as bridge-to-transplantation and relieves workload demand placed on a failing heart allowing for myocardia recovery when used as destination therapy. Stroke is the most devastating complication after ventricular assist device (VAD) implantation, with an incidence of 14-47% over 3-6 months. This complication due to thrombus formation and subsequent transport through the vasculature to cerebral vessels continues to limit the widespread implementation of VAD therapy. Patient-specific computational fluid dynamics (CFD) analysis may elucidate ways to reduce this risk. We employed a multi-scale model of …

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Phase Transformations And Microstructural Evolution In The U-10 Wt.% Mo Alloy With Various Zr Additions At 900c And 650c, Nicholas Eriksson Jan 2015

Phase Transformations And Microstructural Evolution In The U-10 Wt.% Mo Alloy With Various Zr Additions At 900c And 650c, Nicholas Eriksson

Electronic Theses and Dissertations

The Reduced Enrichment for Research and Test Reactor (RERTR) now known as the Material Minimization and Management Reactor Control program (MMMRC) seeks to replace the use of highly enriched uranium (HEU) fuels used in research and test nuclear reactors around the world. The low enriched uranium (LEU) fuels must have fissionable uranium densities comparable to the HEU fuels. After extensive investigation by various researchers around the world, the U-Mo alloys were selected as a promising candidate. The Mo alloyed with U allows for the stabilization of the face-centered cubic ?-U phase, which demonstrated favorable irradiation behavior. However, deleterious diffusional interaction …

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An Agile Roadmap For Live, Virtual And Constructive-Integrating Training Architecture (Lvc-Ita): A Case Study Using A Component Based Integrated Simulation Engine, Tae Woong Park Jan 2015

An Agile Roadmap For Live, Virtual And Constructive-Integrating Training Architecture (Lvc-Ita): A Case Study Using A Component Based Integrated Simulation Engine, Tae Woong Park

Electronic Theses and Dissertations

Conducting seamless Live Virtual Constructive (LVC) simulation remains the most challenging issue of Modeling and Simulation (M&S). There is a lack of interoperability, limited reuse and loose integration between the Live, Virtual and/or Constructive assets across multiple Standard Simulation Architectures (SSAs). There have been various theoretical research endeavors about solving these problems but their solutions resulted in complex and inflexible integration, long user-usage time and high cost for LVC simulation. The goal of this research is to provide an Agile Roadmap for the Live Virtual Constructive-Integrating Training Architecture (LVC-ITA) that will address the above problems and introduce interoperable LVC simulation. …

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Towards Improving Human-Robot Interaction For Social Robots, Saad Khan Jan 2015

Towards Improving Human-Robot Interaction For Social Robots, Saad Khan

Electronic Theses and Dissertations

Autonomous robots interacting with humans in a social setting must consider the social-cultural environment when pursuing their objectives. Thus the social robot must perceive and understand the social cultural environment in order to be able to explain and predict the actions of its human interaction partners. This dissertation contributes to the emerging field of human-robot interaction for social robots in the following ways: 1. We used the social calculus technique based on culture sanctioned social metrics (CSSMs) to quantify, analyze and predict the behavior of the robot, human soldiers and the public perception in the Market Patrol peacekeeping scenario. 2. …

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Providing Context To The Clues: Recovery And Reliability Of Location Data From Android Devices, Connie Bell Jan 2015

Providing Context To The Clues: Recovery And Reliability Of Location Data From Android Devices, Connie Bell

Electronic Theses and Dissertations

Mobile device data continues to increase in significance in both civil and criminal investigations. Location data is often of particular interest. To date, research has established that the devices are location aware, incorporate a variety of resources to obtain location information, and cache the information in various ways. However, a review of the existing research suggests varying degrees of reliability of any such recovered location data. In an effort to clarify the issue, this project offers case studies of multiple Android mobile devices utilized in controlled conditions with known settings and applications in documented locations. The study uses data recovered …

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A Generic Framework For Multi-Method Modeling And Simulation Of Complex Systems Using Discrete Event, System Dynamics And Agent Based Approaches., Konstantinos Mykoniatis Jan 2015

A Generic Framework For Multi-Method Modeling And Simulation Of Complex Systems Using Discrete Event, System Dynamics And Agent Based Approaches., Konstantinos Mykoniatis

Electronic Theses and Dissertations

Decisions about Modeling and Simulation (M&S) of Complex Systems (CS) need to be evaluated prior to implementation. Discrete Event (DE), System Dynamics (SD), and Agent Based (AB) are three different M&S approaches widely applied to enhance decision-making of complex systems. However, single type M&S approaches can face serious challenges in representing the overall multidimensional nature of CS and may result in the design of oversimplified models excluding important factors. Conceptual frameworks are necessary to offer useful guidance for combining and/or integrating different M&S approaches. Although several hybrid M&S frameworks have been described and are currently deployed, there is limited guidance …

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Integrated Maritime Simulation Complex Management, Quality And Training Effectiveness From The Perspective Of Modeling And Simulation In The State Of Florida, Usa (A Case Study), Yaser Sendi Jan 2015

Integrated Maritime Simulation Complex Management, Quality And Training Effectiveness From The Perspective Of Modeling And Simulation In The State Of Florida, Usa (A Case Study), Yaser Sendi

Electronic Theses and Dissertations

Naturally, maritime training simulators at all events are valuable instructional and pedagogical tools. Through the history, the maritime simulation was utilized to train prospective maritime apprentices in whom it has filled the gap left by the acute shortage of opportunities for jobs onboard vessels around the globe. However, professional seafarers are the axis of success and competitiveness in the field of maritime training. They are the ones that, who are well trained and have the responsibilities of their work and the surrounding environment. In order to achieve the success along with effective training skills, both maritime companies and seafarers should …

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Lyapunov-Based Robust And Adaptive Control Design For Nonlinear Uncertain Systems, Kun Zhang Jan 2015

Lyapunov-Based Robust And Adaptive Control Design For Nonlinear Uncertain Systems, Kun Zhang

Electronic Theses and Dissertations

The control of systems with uncertain nonlinear dynamics is an important field of control science attracting decades of focus. In this dissertation, four different control strategies are presented using sliding mode control, adaptive control, dynamic compensation, and neural network for a nonlinear aeroelastic system with bounded uncertainties and external disturbance. In Chapter 2, partial state feedback adaptive control designs are proposed for two different aeroelastic systems operating in unsteady flow. In Chapter 3, a continuous robust control design is proposed for a class of single input and single output system with uncertainties. An aeroelastic system with a trailingedge flap as …

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Mechanism Of Hip Dysplasia And Identification Of The Least Energy Path For Its Treatment By Using The Principle Of Stationary Potential Energy, Mohammed Abdulwahab M. Zwawi Jan 2015

Mechanism Of Hip Dysplasia And Identification Of The Least Energy Path For Its Treatment By Using The Principle Of Stationary Potential Energy, Mohammed Abdulwahab M. Zwawi

Electronic Theses and Dissertations

Developmental dysplasia of the hip (DDH) is a common newborn condition where the femoral head is not located in its natural position in the acetabulum (hip socket). Several treatment methods are being implemented worldwide to treat this abnormal condition. One of the most effective methods of treatment is the use of Pavlik Harness, which directs the femoral head toward the natural position inside the acetabulum. This dissertation presents a developed method for identifying the least energy path that the femoral head would follow during reduction. This is achieved by utilizing a validated computational biomechanical model that allows the determination of …

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Research On High-Performance And Scalable Data Access In Parallel Big Data Computing, Jiangling Yin Jan 2015

Research On High-Performance And Scalable Data Access In Parallel Big Data Computing, Jiangling Yin

Electronic Theses and Dissertations

To facilitate big data processing, many dedicated data-intensive storage systems such as Google File System(GFS), Hadoop Distributed File System(HDFS) and Quantcast File System(QFS) have been developed. Currently, the Hadoop Distributed File System(HDFS) [20] is the state-of-art and most popular open-source distributed file system for big data processing. It is widely deployed as the bedrock for many big data processing systems/frameworks, such as the script-based pig system, MPI-based parallel programs, graph processing systems and scala/java-based Spark frameworks. These systems/applications employ parallel processes/executors to speed up data processing within scale-out clusters. Job or task schedulers in parallel big data applications such as …

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Theoretical And Experimental Investigation Of The Cascading Nature Of Pressure-Swirl Atomization, Pretam Choudhury Jan 2015

Theoretical And Experimental Investigation Of The Cascading Nature Of Pressure-Swirl Atomization, Pretam Choudhury

Electronic Theses and Dissertations

Pressure swirl atomizers are commonly used in IC, aero-engines, and liquid propellant rocket combustion. Understanding the atomization process is important in order to enhance vaporization, mitigate soot formation, design of combustion chambers, and improve overall combustion efficiency. This work utilizes non-invasive techniques such as ultra -speed imaging, and Phase Doppler Particle Anemometry (PDPA) in order to investigate the cascade atomization process of pressure-swirl atomizers by examining swirling liquid film dynamics and the localized droplet characteristics of the resulting hollow cone spray. Specifically, experiments were conducted to examine these effects for three different nozzles with orifice diameters .3mm, .5mm, and .97mm. …

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Data-Driven Simulation Modeling Of Construction And Infrastructure Operations Using Process Knowledge Discovery, Reza Akhavian Jan 2015

Data-Driven Simulation Modeling Of Construction And Infrastructure Operations Using Process Knowledge Discovery, Reza Akhavian

Electronic Theses and Dissertations

Within the architecture, engineering, and construction (AEC) domain, simulation modeling is mainly used to facilitate decision-making by enabling the assessment of different operational plans and resource arrangements, that are otherwise difficult (if not impossible), expensive, or time consuming to be evaluated in real world settings. The accuracy of such models directly affects their reliability to serve as a basis for important decisions such as project completion time estimation and resource allocation. Compared to other industries, this is particularly important in construction and infrastructure projects due to the high resource costs and the societal impacts of these projects. Discrete event simulation …

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Pressurized Metal Bellows Shock Absorber For Space Applications., John Trautwein Jan 2015

Pressurized Metal Bellows Shock Absorber For Space Applications., John Trautwein

Electronic Theses and Dissertations

Numerous spacecraft designs exist for exploring the surfaces of planetary bodies and each have their own advantages and disadvantages. All successful landings have been made by stationary landers or wheeled rovers that rely on one-time use mechanisms, such as crushable aluminum honeycomb shock absorbers or inflatable airbags, to reduce shock loading to the spacecraft during landing. The stationary lander is the simplest type of lander, but can only take data from one location. Wheeled rovers add complexity in exchange for mobility to explore different locations. Rovers are limited by the terrain they can traverse; rovers becoming stuck have ended missions. …

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Performance Optimization Of Lateral-Mode Thin-Film Piezoelectric-On-Substrate Resonant Systems, Hedy Fatemi Jan 2015

Performance Optimization Of Lateral-Mode Thin-Film Piezoelectric-On-Substrate Resonant Systems, Hedy Fatemi

Electronic Theses and Dissertations

The main focus of this dissertation is to characterize and improve the performance of thin-film piezoelectric-on-substrate (TPoS) lateral-mode resonators and filters. TPoS is a class of piezoelectric MEMS devices which benefits from the high coupling coefficient of the piezoelectric transduction mechanism while taking advantage of superior acoustic properties of a substrate. The use of lateral-mode TPoS designs allows for fabrication of dispersed-frequency filters on a single substrate, thus significantly reducing the size and manufacturing cost of devices. TPoS filters also offer a lower temperature coefficient of frequency, and better power handling capability compared to rival technologies all in a very …

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Applications Of Computer Vision Technologies Of Automated Crack Detection And Quantification For The Inspection Of Civil Infrastructure Systems, Liuliu Wu Jan 2015

Applications Of Computer Vision Technologies Of Automated Crack Detection And Quantification For The Inspection Of Civil Infrastructure Systems, Liuliu Wu

Electronic Theses and Dissertations

Many components of existing civil infrastructure systems, such as road pavement, bridges, and buildings, are suffered from rapid aging, which require enormous nation's resources from federal and state agencies to inspect and maintain them. Crack is one of important material and structural defects, which must be inspected not only for good maintenance of civil infrastructure with a high quality of safety and serviceability, but also for the opportunity to provide early warning against failure. Conventional human visual inspection is still considered as the primary inspection method. However, it is well established that human visual inspection is subjective and often inaccurate. …

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Base Flow Recession Analysis For Streamflow And Spring Flow, Debapi Ghosh Jan 2015

Base Flow Recession Analysis For Streamflow And Spring Flow, Debapi Ghosh

Electronic Theses and Dissertations

Base flow recession curve during a dry period is a distinct hydrologic signature of a watershed. The base flow recession analysis for both streamflow and spring flow has been extensively studied in the literature. Studies have shown that the recession behaviors during the early stage and the late stage are different in many watersheds. However, research on the transition from early stage to late stage is limited and the hydrologic control on the transition is not completely understood. In this dissertation, a novel cumulative regression analysis method is developed to identify the transition flow objectively for individual recession events in …

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Propagation Of Unit Location Uncertainty In Dense Storage Environments, Patrick Reilly Jan 2015

Propagation Of Unit Location Uncertainty In Dense Storage Environments, Patrick Reilly

Electronic Theses and Dissertations

Effective space utilization is an important consideration in logistics systems and is especially important in dense storage environments. Dense storage systems provide high-space utilization; however, because not all items are immediately accessible, storage and retrieval operations often require shifting of other stored items in order to access the desired item, which results in item location uncertainty when asset tracking is insufficient. Given an initial certainty in item location, we use Markovian principles to quantify the growth of uncertainty as a function of retrieval requests and discover that the steady state probability distribution for any communicating class of storage locations approaches …

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Sustainability Assessment Of A Municipal Utility Complex: A System Of Systems Approach, Tarek Fahmy Jan 2015

Sustainability Assessment Of A Municipal Utility Complex: A System Of Systems Approach, Tarek Fahmy

Electronic Theses and Dissertations

Construction of municipal utility complexes has to support continuing population growth, economic development, and a widespread of social interest in environmental preservation. Municipalities face challenges in designing, constructing, and operating environmentally sustainable utility complexes, and their primary goal in developing such a complex is to minimize the environmental impact resulting from energy production and waste treatment (both liquid and solid), management, and disposal. However, decision and policy makers lack a system of systems approach that takes into account multiple interdependent systems comprised of the functional system (infrastructure, facilities, operations within the complex…), the economic system, the social/cultural system, and the …

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Exploring 3d User Interface Technologies For Improving The Gaming Experience, Arun Kulshreshth Jan 2015

Exploring 3d User Interface Technologies For Improving The Gaming Experience, Arun Kulshreshth

Electronic Theses and Dissertations

3D user interface technologies have the potential to make games more immersive & engaging and thus potentially provide a better user experience to gamers. Although 3D user interface technologies are available for games, it is still unclear how their usage affects game play and if there are any user performance benefits. A systematic study of these technologies in game environments is required to understand how game play is affected and how we can optimize the usage in order to achieve better game play experience. This dissertation seeks to improve the gaming experience by exploring several 3DUI technologies. In this work, …

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Exploration And Development Of Crash Modification Factors And Functions For Single And Multiple Treatments, Juneyoung Park Jan 2015

Exploration And Development Of Crash Modification Factors And Functions For Single And Multiple Treatments, Juneyoung Park

Electronic Theses and Dissertations

Traffic safety is a major concern for the public, and it is an important component of the roadway management strategy. In order to improve highway safety, extensive efforts have been made by researchers, transportation engineers, Federal, State, and local government officials. With these consistent efforts, both fatality and injury rates from road traffic crashes in the United States have been steadily declining over the last six years (2006~2011). However, according to the National Highway Traffic Safety Administration (NHTSA, 2013), 33,561 people died in motor vehicle traffic crashes in the United States in 2012, compared to 32,479 in 2011, and it …

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A Framework For Safety Training Using Virtual Reality Software, Rana Riad Jan 2015

A Framework For Safety Training Using Virtual Reality Software, Rana Riad

Electronic Theses and Dissertations

Safety training is a vital component to the well-being of individuals in all industries. With technology advancing at the current pace, conventional training methods are no longer the most effective way to communicate information. There is a strong need for safety training that incorporates new methods and forms of communication to obtain higher levels of comprehension. Virtual reality systems offer a highly customizable and interactive form of delivering information to users. This research addresses major gaps in the field of safety training using virtual reality systems and provides a design framework for creating a virtual safety-training system. A model for …

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Mathematical Modeling Of Carbon Removal In The A-Stage Activated Sludge System, Thomas Nogaj Jan 2015

Mathematical Modeling Of Carbon Removal In The A-Stage Activated Sludge System, Thomas Nogaj

Electronic Theses and Dissertations

This research developed a dynamic activated sludge model (ASM) to better describe the overall removal of organic substrate, quantified as chemical oxygen demand (COD), from A-stage high rate activated sludge (HRAS) systems. This dynamic computer model is based on a modified ASM1 (Henze et al., 2000) model. It was determined early in the project that influent soluble COD, which is normally represented by a single state variable in ASM1, had to be subdivided into two state variables (SBs and SBf, or slow and fast fractions) to simulate the performance of A-stage systems. Also, the addition of state variables differentiating colloidal …

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Development Of Velocity Profile Generating Screens For Gas Turbine Components, Joseph Tate Jan 2015

Development Of Velocity Profile Generating Screens For Gas Turbine Components, Joseph Tate

Electronic Theses and Dissertations

Laboratory experiments on components of complex systems such as gas turbines require many conditions to be met. Requirements to be met in order to simulate real world conditions include inlet flow conditions such as velocity profile, Reynold's number, and temperature. The methodology to be introduced designs a velocity profile generating screen to match real world conditions through the use of perforated plates. The velocity profile generating screen is an array of jets arranged in a manner to produce sections of different solidities, a ratio of area that obstructs fluid flow compared to that of the total area. In an effort …

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A Study On The Analyzing Priority Of Limiting Factors In Live, Virtual, And Constructive (Lvc) Simulation Interoperability Using Analytic Hierarchy Process (Ahp) Method, Youngkun Yoo Jan 2015

A Study On The Analyzing Priority Of Limiting Factors In Live, Virtual, And Constructive (Lvc) Simulation Interoperability Using Analytic Hierarchy Process (Ahp) Method, Youngkun Yoo

Electronic Theses and Dissertations

Each Live, Virtual, and Constructive (LVC) simulation model has been developed and used with many benefits. When system developers created each simulation model, focused on specific standards to fit to their own respective purposes. Consequently, there have been interoperability issues among simulation models that have many limitations. To be specific, despite various efforts to achieve and maintain complete interoperability in LVC simulation environment, substantial limiting factors have remained in technical and managerial fields. Thus, analyzing and prioritizing limiting factors in LVC simulation is the effective way to solve interoperability problems while saving budget and time. The purpose of this research …

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