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Modeling Solid Propellant Ignition Events, Daniel A. Smyth
Modeling Solid Propellant Ignition Events, Daniel A. Smyth
Theses and Dissertations
This dissertation documents the building of computational propellant/ingredient models toward predicting AP/HTPB/Al cookoff events. Two computer codes were used to complete this work; a steady-state code and a transient ignition code Numerous levels of verification resulted in a robust set of codes to which several propellant/ingredient models were applied. To validate the final cookoff predictions, several levels of validation were completed, including the comparison of model predictions to experimental data for: AP steady-state combustion, fine-AP/HTPB steady-state combustion, AP laser ignition, fine-AP/HTPB laser ignition, AP/HTPB/Al ignition, and AP/HTPB/Al cookoff. A previous AP steady-state model was updated, and then a new AP …
Fabrication Of Horizontal Silicon Nanowires Using A Thin Aluminum Film As A Catalyst, Khaja Hafeezuddin Mohammed
Fabrication Of Horizontal Silicon Nanowires Using A Thin Aluminum Film As A Catalyst, Khaja Hafeezuddin Mohammed
Graduate Theses and Dissertations
Silicon nanowires have been the topic of research in recent years for their significant attention from the electronics industry to grow even smaller electronic devices. The semiconductor industry is built on silicon. Silicon nanowires can be the building blocks for future nanoelectronic devices. Various techniques have also been reported in fabricating the silicon nanowires. But most of the techniques reported, grow vertical silicon nanowires. In the semiconductor industry, integrated circuits are designed and fabricated in a horizontal architecture i.e. the device layout is flat compared to the substrate. When vertical silicon nanowires are introduced in the semiconductor industry, a whole …
Investigation Of Aluminum Equation Of State Generation, Aaron Ward
Investigation Of Aluminum Equation Of State Generation, Aaron Ward
Master's Theses (2009 -)
There are many forms and methods to construct equations of state, EOSs. These methods are usually tailored for the particular problem of interest. Here, the EOSs of interest are those used in modeling shock responses. These EOSs cover a wide range of physical characteristics such as detonation and explosions, armor and anti-armor materials, and space structures protection. Aluminum will be the primary focus of this work. Aluminum was chosen because it has been studied in great length in the shock regime and is a common component in shock experiments and space type vehicles.
Friction Bit Joining Of 5754 Aluminum To Dp980 Ultra-High Strength Steel: A Feasibility Study, Britney Weickum
Friction Bit Joining Of 5754 Aluminum To Dp980 Ultra-High Strength Steel: A Feasibility Study, Britney Weickum
Theses and Dissertations
In this study, the dissimilar metals 5754 aluminum and DP980 ultra-high strength steel were joined using the friction bit joining (FBJ) process. The friction bits were made using one of three steels: 4140, 4340, or H13. Experiments were performed in lap shear, T-peel, and cross tension configurations, with the 0.070" thick 5754 aluminum alloy as the top layer through which the friction bit cut, and the 0.065" thick DP980 as the bottom layer to which the friction bit welded. All experiments were performed using a computer controlled welding machine that was purpose-built and provided by MegaStir Technologies. Through a series …
The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner
The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner
Theses and Dissertations
Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a …
Impurity And Interdiffusion In The Magnesium-Aluminum System, Sarah Tiffany Brennan
Impurity And Interdiffusion In The Magnesium-Aluminum System, Sarah Tiffany Brennan
Electronic Theses and Dissertations
Magnesium alloys offer a base of lightweight engineering materials for electronic, military and transportation applications where weight reduction is crucial for higher efficiency. Understanding fundamental diffusion behavior in Mg alloys elicits better materials properties through the optimization of processing techniques and heat treatments, whose material responses are affected by diffusion. The main objective of this study is to provide a clear, comprehensive description of the diffusion behavior in the technically important magnesium-aluminum binary metallic system. In this study, diffusion in the Mg-Al system was observed through solid diffusion couples and thin film specimens in the temperature range of 673-523K. The …
Mechanical Characterization And Numerical Simulation Of A Light-Weight Aluminum A359 Metal-Matrix Composite, James P. Demarco
Mechanical Characterization And Numerical Simulation Of A Light-Weight Aluminum A359 Metal-Matrix Composite, James P. Demarco
Electronic Theses and Dissertations
Aluminum metal-matrix composites (MMCs) are well positioned to replace steel in numerous manufactured structural components, due to their high strength-to-weight and stiffness ratios. For example, research is currently being conducted in the use of such materials in the construction of tank entry doors, which are currently made of steel and are dangerously heavy for military personnel to lift and close. However, the manufacture of aluminum MMCs is inefficient in many cases due to the loss of material through edge cracking during the hot rolling process which is applied to reduce thick billets of as-cast material to usable sheets. In the …
Effect Of Process Parameter On Temperature Distribution, Microstructure, And Mechanical Properties Of Self-Reacting Friction Stir Welded Aluminum Alloy 6061-T651, Monica Adriana Torres
Effect Of Process Parameter On Temperature Distribution, Microstructure, And Mechanical Properties Of Self-Reacting Friction Stir Welded Aluminum Alloy 6061-T651, Monica Adriana Torres
Open Access Theses & Dissertations
Self-reacting friction stir welding is the latest FSW tool configuration developed, it employs two shoulders--one on top and one on the bottom of the workpiece-- this tool configuration offers many advantages over conventional welding techniques. However, the current lack of information and specifications limits its understanding and application. This investigation analyzed the effect of process parameters on temperature distribution, microstructure evolution, and final mechanical properties of 6061-T651 SR-FS welds. A factorial experiment was carried out, in which three-process parameters were analyzed--rotational speed, travel speed, and tool plunge force-- three levels were analyzed for each parameter, except for a tool plunge …
Combustion Of Lunar Regolith Mixed With Energetic Additives: Thermodynamic Calculations And Experimental Studies, Francisco Alvarez
Combustion Of Lunar Regolith Mixed With Energetic Additives: Thermodynamic Calculations And Experimental Studies, Francisco Alvarez
Open Access Theses & Dissertations
The future of space exploration will require longer missions in order to better understand the conditions of near-Earth celestial objects, like the Moon or Mars. Future space missions will require the development of goods, such as propulsion fuel and structural materials, produced using the extraterrestrial resources available. The area that develops these technologies is called In-Situ Resource Utilization (ISRU). ISRU allows reducing the payload, and as a consequence reduces the energy consumption and cost of space travel. The production of structural materials on the Moon can be accomplished using Self-Propagating High-Temperature Synthesis (SHS). This work describes the combination of ISRU …
Process-Dependent Microstructure And Severe Plastic Deformation In Sicp?? Reinforced Aluminum Metal Matrix Composites, Catalina Uribe-Restrepo
Process-Dependent Microstructure And Severe Plastic Deformation In Sicp?? Reinforced Aluminum Metal Matrix Composites, Catalina Uribe-Restrepo
Electronic Theses and Dissertations
Discontinuously reinforced MMCs with optimized microstructure are sought after for exceptional high strain rate behavior. The microstructure evolution of a stir-cast A359 aluminum composite reinforced with 30 vol.% SiCp after isothermal anneal, successive hot-rolling, and high strain rate deformation has been investigated. Quantitative microstructural analysis was carried out for the as-cast, annealed (470°C, 538°C and 570°C) and successively hot rolled specimens (64, 75, 88, and 96% rolling reductions). Selected composites were also examined after high strain rate deformation. X-ray diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy were employed for microstructural characterization. The strength and ductility of the …
The Effects Of Solidification Under Pressure On Properties Of Cast Aluminum Alloys, Santosh B. Ghanti
The Effects Of Solidification Under Pressure On Properties Of Cast Aluminum Alloys, Santosh B. Ghanti
All ETDs from UAB
The mechanical properties of aluminum alloy castings are affected by porosity which is caused by a combination of dissolved gases and shrinkage. The objective of this research is to study the effects of solidification under pressure on microstructure and mechanical properties of two aluminum alloys, A356-T6 and A206-T6. Wedge-shaped aluminum castings were produced with chemically bonded sand molds. Castings were poured at 704ºC (1300ºF) or 760ºC (1400ºF) and solidified under 1 atmosphere or 10 atmospheres of applied pressure. Density, x-ray radiography, metallographic inspection, and tensile testing were performed on samples from various section sizes of the castings. For aluminum alloy …
Design, Fabrication, And Testing Of High-Transparency Deep Ultra-Violet Contacts Using Surface Plasmon Coupling In Subwavelength Aluminum Meshes, Clarisse Mazuir
Design, Fabrication, And Testing Of High-Transparency Deep Ultra-Violet Contacts Using Surface Plasmon Coupling In Subwavelength Aluminum Meshes, Clarisse Mazuir
Electronic Theses and Dissertations
The present work aims at enhancing the external quantum efficiencies of ultra-violet (UV) sensitive photodetectors (PDs) and light emitting diodes (LEDs)for any light polarization. Deep UV solid state devices are made out of AlGaN or MgZnO and their performances suffer from the high resistivity of their p-doped regions. They require transparent p-contacts; yet the most commonly used transparent contacts have low transmission in the UV: indium tin oxide (ITO) and nickel-gold (Ni/Au 5/5 nms) transmit less than 50% and 30% respectively at 300 nm. Here we investigate the use of surface plasmons (SPs) to design transparent p-contacts for AlGaN devices …