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Full-Text Articles in Engineering
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Theses and Dissertations
The majority of literature regarding the numerical simulation of arc discharges in gaseous environments has used a plasma physics approach. Virtually all simulations treat the discharge as an idealized gaseous plasma, which can be described by temperature, pressure, and electric field. This approach can work well if the media is a shielding gas such as Argon; however, the approach does not work well for processes such as underwater welding, EDM, and underwater discharges used to generate high purity particles. The reason these discharges do not have many extensive simulation efforts as described in the literature is because they occur in …
Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas
Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas
Theses and Dissertations
A novel method of calculating viscosity from molecular dynamics simulations is developed, benchmarked, and tested. The technique is a transient method which has the potential to reduce CPU requirements for many conditions. An initial sinusoidal velocity profile is overlaid upon the peculiar velocities of the individual molecules in an equilibrated simulation. The transient relaxation of this initial velocity profile is then compared to the corresponding analytical solution of the momentum equation by adjusting the viscosity-related parameters in the constitutive equation that relate the shear rate to the stress tensor. The newly developed Transient Molecular Dynamics (TMD) method was tested for …
Probabilistic Remediation Evaluation Model For Chlorinated Solvents Considering Uncertainty, Hailian Liang
Probabilistic Remediation Evaluation Model For Chlorinated Solvents Considering Uncertainty, Hailian Liang
All Dissertations
The complex processes and expensive costs of source and plume remediation of dense, non-aqueous phase liquid (DNAPL) complicate the decision-making process for site remediation. Selection of remediation alternatives has been a big challenge due to the lack of tools that simultaneously evaluate the effectiveness of source and plume remediation and access the uncertainties in all major parameters. In this research, a new probabilistic remediation model, Probabilistic Remediation Evaluation Model for Chlorinated solvents sites (PREMChlor), has been developed. This is achieved through linking the analytical model REMChlor to a Monte Carlo modeling simulation package GoldSim via a FORTRAN Dynamic Link Library …
Computational Investigations Of Characteristic Performance Improvements For Subkilogram Laser Micropropulsion, Richard Joel Thompson
Computational Investigations Of Characteristic Performance Improvements For Subkilogram Laser Micropropulsion, Richard Joel Thompson
Masters Theses
Experimental investigations have evaluated the feasibility of using laser-driven plasma microthrusters for small-thrust, high-specific-impulse space maneuvers, particularly for micro- and nanosatellite missions. Recent work made use of the Mach2 hydromagnetics code for the construction of an adequate computational model of the micro-thruster opera- tion. This thesis expounds on this previous work by extending the computational modeling capabilities, allowing for the determination of plasma plume properties and characteristic performance assessment of the microthruster; this allows for further computational investi- gation of the performance improvements achieved by new design considerations. Two par- ticular design changes are implemented and measured: (i) the simulation …
Development Of A Nonlinear Ride Quality Model To Aid In Tweelå© Parameter Selection, Marc Paradiso
Development Of A Nonlinear Ride Quality Model To Aid In Tweelå© Parameter Selection, Marc Paradiso
All Theses
The ride comfort of a vehicle is very important to both automotive and tire manufacturers. Unfortunately the ride comfort provided by the tire has an inverse relationship with the handling ability of the vehicle. Michelin has sought to decouple ride comfort and handling capability by developing a non-pneumatic tire they have dubbed the TWEEL©. To better understand what effects fitting a TWEEL with specific characteristics would have on the ride comfort of a vehicle a computer simulation was developed to study the effects of TWEEL stiffness and deflection on ride comfort.
The vehicle model used in the simulation is a …
Unified Large And Small Signal State-Space Based Modeling And Symbolic Simulation For Pwm Converters, Ehab Shoubaki
Unified Large And Small Signal State-Space Based Modeling And Symbolic Simulation For Pwm Converters, Ehab Shoubaki
Electronic Theses and Dissertations
In this Dissertation, which concentrates on discrete modeling for control purposes of DC/DC converters and simulation through symbolic techniques. A Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulation of the converter switches, and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulation, this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic …
Safety And Operational Evaluation Of Dynamic Lane Merging In Work Zones, Rami Harb
Safety And Operational Evaluation Of Dynamic Lane Merging In Work Zones, Rami Harb
Electronic Theses and Dissertations
Traffic safety and mobility of roadway work zones have been considered to be one of the major concerns in highway traffic safety and operations in Florida. In intent to expose Florida's work zones crash characteristics, the Florida Traffic Crash Records Database for years 2002, 2003 and 2004 were explored. Statistical models were estimated and Florida's work zone crash traits for single vehicle crashes and two-vehicle crashes were drawn. For the single-vehicle crashes, trucks were found more likely to be involved in single vehicle crashes in freeway work zones compared to freeways without work zones. Straight level roadways are significantly affected …
Dod Acquisition Workforce Education: An Sba Education Case Study, Richard Davenport
Dod Acquisition Workforce Education: An Sba Education Case Study, Richard Davenport
Electronic Theses and Dissertations
A Department of Defense (DoD) M&S education task force is in the process of studying the Modeling and Simulation (M&S) education of the acquisition workforce. Historically, DoD acquisition workforce education is not referred to as education, but rather what the Defense Acquisition University (DAU) refers to as "practitioner training, career management, and services." The DAU is the organization primarily responsible for training the DoD acquisition corps in conjunction with service schools and strategic partners in the civilian sector. DAU programs primarily focus on program management, contracting, and management of logistics across the system life cycle. Further, the examples and cases …
Presence-Dependent Performance Differences Between Virtual Simulations And Miniature Worlds, Andre Huthmann
Presence-Dependent Performance Differences Between Virtual Simulations And Miniature Worlds, Andre Huthmann
Electronic Theses and Dissertations
The purpose of simulation is to avoid reality-based constraints by the implemen-tation of a synthetic model. Based on this advantage, interactive simulations have conquered all areas of applications from acquisition, and training, to research. Simulation results are transferred in many ways into reality and conclusions are drawn from the simulation to the application. Many anecdotal observations on human-in-the-loop simulations have shown a significant difference in actor behavior between simulations and reality-based applications. It seems that the factors that makes simulation so attractive, namely the absence of constraints and especially of imminent danger for persons and equipment, influence the behavior and …
The Calibration, Validation, And Comparison Of Vissim Simulations Using The Two-Fluid Model, Jeremy Crowe
The Calibration, Validation, And Comparison Of Vissim Simulations Using The Two-Fluid Model, Jeremy Crowe
Electronic Theses and Dissertations
The microscopic traffic simulation program VISSIM is a powerful tool that has been used by transportation engineers and urban planners around the world. A VISSIM simulation is meant to depict the performance of the physical road network through the use of modeling tools and behavioral parameters. The process which gets the model to the point of matching real world conditions is called calibration and requires a means of relating the real world to the simulated world. The topic of this thesis discusses a new means of calibration using the two-fluid model. The two-fluid model is a macroscopic modeling technique which …
High Voltage Dc Converter Systems Modeling, Simulation And Analysis, Manish A. Dalal
High Voltage Dc Converter Systems Modeling, Simulation And Analysis, Manish A. Dalal
Browse all Theses and Dissertations
The thesis provides insights into important modeling techniques to model the converter system, machine design, control and power stages and integration of the various sub systems to simulate the system level performance. This innovative modeling and simulation project is very relevant to optimizing the system performance, designing the sub circuits, components selection, predicting the system stability and impulse responses. The thesis presents modeling and simulation of three different 270VDC converter systems and comparing their performances against each other. The 270VDC converter system accepts either Generator 3-phase AC voltages or fixed three voltage source followed by single or dual converter stages …
Photocatalytic Reaction In Monolithic Optical Fiber Reactor With Inverse Opal Catalyst, Maoming Ren
Photocatalytic Reaction In Monolithic Optical Fiber Reactor With Inverse Opal Catalyst, Maoming Ren
LSU Doctoral Dissertations
The development of photocatalytic reactor is essential for the successful application of heterogeneous semiconductor in environmental study, which has been shown to be photoactive and effective to oxidate organic pollutant and photoreduce CO2 to useful compounds. In this dissertation, a monolithic optical fiber reactor (MOFR) coated with inverse opal titania, which uses optical fibers as light-transmitting conductor and support of catalyst, was developed for both photodegradation and photoreduction. 1,2-dichlorobenzene, a volatile organic compound (VOC), was selected as the organic pollutant. This configuration of reactor and catalyst provides a high surface area, enhances mass transfer within the catalyst, manipulates photons transmission …
Passenger Car Equivalents Of Trucks Under Lane Restriction And Differential Speed Limit Policies On Four Lane Freeways, John Stanley
Passenger Car Equivalents Of Trucks Under Lane Restriction And Differential Speed Limit Policies On Four Lane Freeways, John Stanley
LSU Master's Theses
Lane restriction for trucks and differential speed limits for trucks and cars are becoming more common and feasible policies to improve the efficiency and safety of a freeway. It is believed that passenger car equivalents for trucks are impacted by these non typical freeway operating conditions, which are not explicitly addressed by the latest edition of the Highway Capacity Manual. Using simulated and real world data an elevated 18- mile four lane freeway was modeled under the restriction policies. The section which was used as a test bed was simulated under various control variables. Some of the control variables used …