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Power Supply On Chip Dc-Dc Converter Identification Using Black-Box Modeling Techniques, Charles Craig Bilberry
Power Supply On Chip Dc-Dc Converter Identification Using Black-Box Modeling Techniques, Charles Craig Bilberry
Theses and Dissertations
With recent developments in power conversion technologies and market trends that are driving those technologies toward further miniaturization and greater integration, the need for verifying an empirically based modeling methodology for proprietary power converters such as Power Supply on Chip (PwrSoC) products has risen significantly. This need motivates the investigation of black-box models which require little or no knowledge of the internal workings of a system, for those areas of industry adopting PwrSoC technology as a point-of-load solution. This thesis reports a black-box modeling method tailored to accommodate but not limited to the requirements of a specific commercially available PwrSoC …
On Modeling And Experimental Validation Of Extrusion Process Of Lightweight Alloys, Abdul Afoo H Parkar
On Modeling And Experimental Validation Of Extrusion Process Of Lightweight Alloys, Abdul Afoo H Parkar
Theses and Dissertations
Laboratory-scale extrusion facilitated a parametric study of the metal extrusion process under controlled conditions. Hot extrusion experiments were performed on billets of both aluminum Al1100 as well as, magnesium alloys AZ61 and AM30. Tests were designed and executed with the purpose of recording load and temperature data to validate full-scale thermo-mechanical simulations performed with the commercial code HyperXtrude. Various aspects of flat die and conical die extrusion were observed, studied and modeled with the code. Conventional sine hyperbolic inverse material model was used in the simulations due to present limitations of HyperXtrude. Although this model showed a perfect viscoplastic response …
An Evaluation Of Constitutive Laws And Their Ability To Predict Flow Stress Over Large Variations In Temperature, Strain, And Strain Rate Characteristic Of Friction Stir Welding, Katherine Lynn Kuykendall
An Evaluation Of Constitutive Laws And Their Ability To Predict Flow Stress Over Large Variations In Temperature, Strain, And Strain Rate Characteristic Of Friction Stir Welding, Katherine Lynn Kuykendall
Theses and Dissertations
Constitutive laws commonly used to model friction stir welding have been evaluated, both qualitatively and quantitatively, and a new application of a constitutive law which can be extended to materials commonly used in FSW is presented. Existing constitutive laws have been classified as path-dependent or path-independent. Path-independent laws have been further classified according to the physical phenomena they capture: strain hardening, strain rate hardening, and/or thermal softening. Path-dependent laws can track gradients in temperature and strain rate characteristic to friction stir welding; however, path-independent laws cannot. None of the path-independent constitutive laws evaluated has been validated over the full range …
Hexahedral Mesh Refinement Using An Error Sizing Function, Gaurab Paudel
Hexahedral Mesh Refinement Using An Error Sizing Function, Gaurab Paudel
Theses and Dissertations
The ability to effectively adapt a mesh is a very important feature of high fidelity finite element modeling. In a finite element analysis, a relatively high node density is desired in areas of the model where there are high error estimates from an initial analysis. Providing a higher node density in such areas improves the accuracy of the model and reduces the computational time compared to having a high node density over the entire model. Node densities can be determined for any model using the sizing functions based on the geometry of the model or the error estimates from the …
A Simulation Environment For A Personal Portable Power System, Shane Leland Morrison
A Simulation Environment For A Personal Portable Power System, Shane Leland Morrison
Theses and Dissertations
With the increased requirements for personal portable power systems to be more capable and better matched to the load and the mission, manufacturers have become interested in improved methods for predicting the performance of these systems. Personal portable power systems must meet challenging energy and portability requirements that require better predictive knowledge of these systems in integrated systems with realistic mission scenarios. This thesis presents the development of a modeling and simulation environment to further expand and predict the needs and requirements of personal portable power systems. The proposed personal portable power system is a diverse system consisting of energy …
Assessment And Prediction Of Streambank Erosion Rates In A Southeastern Plains Ecoregion Watershed In Mississippi, John Jairo Ramirez Avila
Assessment And Prediction Of Streambank Erosion Rates In A Southeastern Plains Ecoregion Watershed In Mississippi, John Jairo Ramirez Avila
Theses and Dissertations
The Town Creek Watershed (TCW) is a representative area of the Tombigbee River Basin and the Southeastern Plains Ecoregion in Mississippi. The principal channel and four main tributaries have been included for several years within the MS Section 303(d) list of waterbodies biologically impaired due to sediment. The TMDL developed for TCW recommended that streams located near cultivated lands, road crossings and construction activities are a priority for streambank and riparian buffer zone restoration and sediment loads reduction. Development of remedial measures and future BMPs within TCW for reducing water quality impairment and downstream dredging costs requires identification of sediment …
Modeling Eurasian Watermilfoil (Myriophyllum Spicatum) Habitat With Geographic Information Systems, Joby Michelle Prince
Modeling Eurasian Watermilfoil (Myriophyllum Spicatum) Habitat With Geographic Information Systems, Joby Michelle Prince
Theses and Dissertations
Eurasian watermilfoil (Myriophyllum spicatum) habitat was predicted at multiple scales, including a lake, regional, and national level. This dissertation illustrates how habitat can be predicted for M. spicatum using publically-available data for both presence and environmental variables. Models were generated using statistical procedures and quantative methods to determine where the greatest likelihood of presence was located. For the single lake, presence and absence data were available, but the larger-scale models used presence-only methods of prediction. These models were paired with a Geographic Information System so that data could be visualized on a map. For the selected lake, Pend Oreille (Idaho), …
Accelerating Finite State Projection Through General Purpose Graphics Processing, Thomas Trimeloni
Accelerating Finite State Projection Through General Purpose Graphics Processing, Thomas Trimeloni
Theses and Dissertations
The finite state projection algorithm provides modelers a new way of directly solving the chemical master equation. The algorithm utilizes the matrix exponential function, and so the algorithm’s performance suffers when it is applied to large problems. Other work has been done to reduce the size of the exponentiation through mathematical simplifications, but efficiently exponentiating a large matrix has not been explored. This work explores implementing the finite state projection algorithm on several different high-performance computing platforms as a means of efficiently calculating the matrix exponential function for large systems. This work finds that general purpose graphics processing can accelerate …
Broadband Pumping Effects On The Diode Pumped Alkali Laser, Paul Nathaniel Jones
Broadband Pumping Effects On The Diode Pumped Alkali Laser, Paul Nathaniel Jones
Theses and Dissertations
This research seeks to gain greater insight on the mechanics of The Diode Pumped Alkali Laser through analytic modeling techniques. This work is an extension to a previous model developed by Dr. Gordon Hager, and focuses on the addition of pump-beam bandwidth. Specifically, it seeks to determine the effect that broadband pumping has on laser performance. The model incorporates all the fundamental parameters within the laser system, including alkali concentrations, collision partner concentrations, pump bandwidth, length and temperature of gain medium, transmission, and reflectivity. Baseline operating conditions set Rubidium (Rb) concentrations ranging from 1012 - 1014 atoms/cm3 …