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Automated Flow Path Design Optimization Using Mesh Morphing, William Dennis Gough
Automated Flow Path Design Optimization Using Mesh Morphing, William Dennis Gough
Theses and Dissertations
The use of CAD models and CFD analysis has become an essential part of fluid flow design. To reduce the time spent determining a design, optimization frameworks have been implemented to automate the process. Mesh morphing has been implemented within these frameworks to further reduce the time needed. While optimization methods have been developed to optimize a fluid flow path, the optimum design needs to be recreated in a CAD model. A method has been developed which eliminates the need to recreate the optimal results in CAD. This is accomplished by using mesh morphing, CAD and CFD together in an …
Analytical Comparison Of Multimicrophone Probes In Measuring Acoustic Intensity, Curtis P. Wiederhold
Analytical Comparison Of Multimicrophone Probes In Measuring Acoustic Intensity, Curtis P. Wiederhold
Theses and Dissertations
In the late 1970s, a method was developed to estimate acoustic intensity in one dimension by taking the cross-spectral density of two closely-spaced microphone signals. Since then, multimicrophone probes have been developed to measure three-dimensional intensity as well as energy density. Their usefulness has led to the design of various types of multimicrophone probes, the most common being the four-microphone orthogonal, the four-microphone regular tetrahedron, and the six-microphone designs. These designs generally either consist of microphones suspended in space near each other or mounted on the surface of a sphere. This work analytically compares the relative merits of each probe …
Sheet-Stamping Process Simulation And Optimization, Cynthia M. Tamasco
Sheet-Stamping Process Simulation And Optimization, Cynthia M. Tamasco
Theses and Dissertations
This thesis presents the development and implementation of a generalized optimization framework for use in sheet-stamping process simulation by finite element analysis. The generic framework consists of three main elements: a process simulation program, an optimization code, and a response filtering program. These elements can be filled by any combination of applicable software packages. Example sheet-stamping process simulations are presented to demonstrate the usage of the framework in various forming scenarios. Each of the example simulations is presented with a sensitivity analysis. These examples include analysis of a 2-dimensional single-stage forming, a 2-dimensional multi-stage forming, and two different 3-dimensional single-stage …
Modeling Wireless Networks For Rate Control, David C. Ripplinger
Modeling Wireless Networks For Rate Control, David C. Ripplinger
Theses and Dissertations
Congestion control algorithms for wireless networks are often designed based on a model of the wireless network and its corresponding network utility maximization (NUM) problem. The NUM problem is important to researchers and industry because the wireless medium is a scarce resource, and currently operating protocols such as 802.11 often result in extremely unfair allocation of data rates. The NUM approach offers a systematic framework to build rate control protocols that guarantee fair, optimal rates. However, classical models used with the NUM approach do not incorporate partial carrier sensing and interference, which can lead to significantly suboptimal performance when actually …
Automated Multidisciplinary Optimizations Of Conceptual Rocket Fairings, Ronald S. Smart
Automated Multidisciplinary Optimizations Of Conceptual Rocket Fairings, Ronald S. Smart
Theses and Dissertations
The purpose of this research is to develop and architect a preliminary multidisciplinary design optimization (MDO) tool that creates multiple types of generalized rocket fairing models. These models are sized relative to input geometric models and are analyzed and optimized, taking into account the primary objectives, namely the structural, thermal, and aerodynamic aspects of standard rocket flights. A variety of standard nose cone shapes is used as optimization proof of concept examples, being sized and compared to determine optimal choices based on the input specifications, such as the rocket body geometry and the specified trajectory paths. Any input models can …
Analytical Modeling And Optimization Of A Thermoelectric Heat Conversion System Operating Betweeen Fluid Streams, Stephen H. Taylor
Analytical Modeling And Optimization Of A Thermoelectric Heat Conversion System Operating Betweeen Fluid Streams, Stephen H. Taylor
Theses and Dissertations
Analytical, closed-form solutions governing thermoelectric behavior are derived. An analytical model utilizing a thermal circuit is presented involving heat transfer into, through, out of, and around a thermoelectric device. A nondimensionalization of the model is presented. Linear heat transfer theory is applied to the model to obtain a series of closed form equations predicting net power output for the thermoelectric device. Fluid streams flowing through shrouded heat sinks with square pin fins are considered for the thermal pathways to and from the device. Heat transfer and pressure drop are characterized in a manner conducive to an analytical model using previously …
Vapor-Grown Carbon Nanofiber/Vinyl Ester Nanocomposites: Designed Experimental Study Of Mechanical Properties And Molecular Dynamics Simulations, Sasan Nouranian
Vapor-Grown Carbon Nanofiber/Vinyl Ester Nanocomposites: Designed Experimental Study Of Mechanical Properties And Molecular Dynamics Simulations, Sasan Nouranian
Theses and Dissertations
The use of nanoreinforcements in automotive structural composites has provided promising improvements in their mechanical properties. For the first time, a robust statistical design of experiments approach was undertaken to demonstrate how key formulation and processing factors (nanofiber type, use of dispersing agent, mixing method, nanofiber weight fraction, and temperature) affected the dynamic mechanical properties of vapor-grown carbon nanofiber (VGCNF)/vinyl ester (VE) nanocomposites. Statistical response surface models were developed to predict nanocomposite storage and loss moduli as functions of significant factors. Only ~0.50 parts of nanofiber per hundred parts resin produced a roughly 20% increase in the storage modulus versus …
Multi-Objective Design Optimization Framework For Structural Health Monitoring, Danny Loren Parker
Multi-Objective Design Optimization Framework For Structural Health Monitoring, Danny Loren Parker
Theses and Dissertations
The purpose of this dissertation is to demonstrate the ability to design health monitoring systems from a systematic perspective and how, with proper sensor and actuator placement, damage occurring in a structure can be detected and tracked. To this end, a design optimization was performed to determine the best locations to excite the structure and to collect data while using the minimum number of sensors. The type of sensors used in this design optimization was uni-axis accelerometers. It should be noted that the design techniques presented here are not limited to accelerometers. Instead, they allow for any type of sensor …
A Minimum Spanning Tree Based Clustering Algorithm For High Throughput Biological Data, Harun Pirim
A Minimum Spanning Tree Based Clustering Algorithm For High Throughput Biological Data, Harun Pirim
Theses and Dissertations
A new minimum spanning tree (MST) based heuristic for clustering biological data is proposed. The heuristic uses MSTs to generate initial solutions and applies a local search to improve the solutions. Local search transfers the nodes to the clusters with which they have the most connections, if this transfer improves the objective function value. A new objective function is defined and used in the heuristic. The objective function considers both tightness and separation of the clusters. Tightness is obtained by minimizing the maximum diameter among all clusters. Separation is obtained by minimizing the maximum number of connections of a gene …
Control Of Multigenerators For The All-Electric Ship, Yamilka Isabel Baez Rivera
Control Of Multigenerators For The All-Electric Ship, Yamilka Isabel Baez Rivera
Theses and Dissertations
The next generation of U.S. Navy ships will see the integration of the propulsion and electrical systems as part of the all-electric ship. This new architecture brings advantages and challenges. One of the challenges is to develop a stable power system that can ride through various issues such as faults or changes in load. style='mso-spacerun:yes'> While terrestrial systems have been studied for a long time related to stability, the unique characteristics of the shipboard power system mean that not all of these results are directly applicable to the all-electric ship. Because of the new shipboard power system structure, more generators …
Characterization Of A Boron Carbide Heterojunction Neutron Detector, James E. Bevins
Characterization Of A Boron Carbide Heterojunction Neutron Detector, James E. Bevins
Theses and Dissertations
New methods for neutron detection have become an important area of research in support of national security objectives. In support of this effort, p-type B5C on n-type Si heterojunction diodes have been built and tested. This research sought to optimize the boron carbide (BC) diode by coupling the nuclear physics modeling capability of GEANT4 and TRIM with the semiconductor device simulation tools. Through an iterative modeling process of controllable parameters, optimal device construction was determined such detection efficiency and charge collection were optimized. This allows an estimation of expected charge collection and efficiency given a set of operating …