Mechanical Engineering Commons^™

Development Of A Micro-Catbed For Miniature Thrusters, Chance Paul Garcia

Open Access Theses & Dissertations

The goal of this work is to develop a micro catalytic bed for miniature thrusters. A test bed was constructed for experimental testing to characterize several parts of the micro catalytic bed. The reactant fluid studied is 90% Hydrogen Peroxide (H2O2) by weight. Three different cross sectional area designs were tested to determine decomposition efficiency, temperature reaction propensity, optimum flow rate, and temperature distribution across each bed. The products of decomposition were condensed to measure the oxygen released from decomposition. The results will be used to develop the basis for a micro catalytic bed design to implement into future miniature …

Processing Of Zrb2-Zrc-Zrxsiy Ceramic By Reactive Metal Penetration, Nischel B. Maheswaraiah

Open Access Theses & Dissertations

The processing of ZrB2-ZrC-ZrxSiy composite by reactive metal penetration was investigated as a successor to the ZrB2-SiC composites for hypersonic vehicles application, which cannot be used for extended time at temperatures greater than 1600C due to formation of SiO and CO gases. Zirconium (Zr), zirconium disilicide (ZrSi2), and boron carbide (B4C) were reacted in graphite crucibles for 60, 120, 180, and 240 minutes. Microscopy and x-ray diffraction (XRD) deduced the formation of a heterogeneous microstructure of ZrB2-ZrC-ZrxSiy precipitates surrounded by a solidified Zr-Si melt. Unreacted boron carbide was observed in samples held at 1860C for 60 minutes and 120 minutes, …

Combustion Characteristics Of Alh3 Flame, Sudipa Sarker

Open Access Theses & Dissertations

The combustion characteristics of Al hydride and Al were compared using a combustion chamber. Burning rate, ignition energy and temperature at atmospheric temperature and pressure in carbon dioxide and O2 were tested with a volumetric flow rate that ranged from 10 to 50% in Ar. A spark ignition system was used to ignite the Alane and Aluminum. The combustion rate was measured using a high speed camera. Results showed the combustion rate of Alane and Aluminum decreases with increasing volumetric flow rate of oxidizer. And the combustion rate of Alane is higher than that of Aluminum. Alane needs more ignition …

Scaffold Based In-Vitro Osteodistraction For Bone Tissue Engineering, Cesar Adrian Terrazas

Open Access Theses & Dissertations

Engineering of hard tissues such as bone is a challenge because of the limited ability of the body to heal large defects. Current treatment options, such as employing bone sections from the patient or a deceased donor have been utilized for some time now with various degrees of success. However, these methods still exhibit many limitations such as limited supply and the possibility of transmission of disease.

To address the many limitations of bone grafts, synthetic engineered substitutes have been developed and widely researched for nearly three decades. Generally termed scaffolds, these are matrices that serve the purpose of temporary …

Multidisciplinary Collaborative Model For Complex, Angel Ernesto Delgado

Open Access Theses & Dissertations

Nowadays, most devices with advanced technology require the development of embedded systems with mechanical and electrical components as well as software including more than one discipline. These are devices that are usually complex in terms of composition and functionality and that design must follow a methodology in order to successfully design and launch a device of this nature. Hence, the assembly of a multidisciplinary engineering group is required to carry out such complex devices and develop a fully functional product. The group may also need an expert on the field that can provide guidance and knowledge where needed. This is …

Sensitivity Analysis Of The Johnson-Cook Plasticity Model For Hypervelocity Impacts: A Hydro-Code Study, Carlos David Castellanos

Open Access Theses & Dissertations

Computer simulations have been in use for decades in the modeling of hypervelocity impacts and general large deformation problems. Several computer codes have been developed to simulate this type of problems under a variety of geometric configurations and for any number of materials. These codes make use of several constitutive material models to simulate the response of the material under a variety of thermo-mechanical conditions. The Johnson-Cook constitutive model is widely used in the simulation hypervelocity impacts for the simulation of crater formation and even perforation of target structures. This thesis presents the results of a sensitivity study of this …

Automated Fluid Handling And Leveling System For Multiple Material Stereolithography, Yinko I. Grajeda

Open Access Theses & Dissertations

This work addresses the development of an automated multiple material fluid handling and leveling system for its implementation into a Multiple-Material Stereolithography (MMSL) apparatus. A patent filed by Wicker et al. (US Patent 7,556,490) disclosing a MMSL apparatus served as the basis for the development of this work. The system is designed to operate in a variety of MMSL apparatus configurations. Fluid vats are designed to meet the enclosure constraints, facilitate the interface to the pump and sensor, and support the handling of the fluids. Due to its fluid isolation and bi-directional flow capabilities, a digital drive peristaltic pump is …

An Investigation On Pulsing Performance Of Mn Class Bi-Propellant Thrusters, Carlos Francisco Gomez

Open Access Theses & Dissertations

With the advancement of technology and machining methods, considerable attention has been focused in manufacturing micro thrusters for micro spacecraft applications (Yetter et al, 2003). Micro propulsion systems are currently being investigated for Miniature Kill Vehicles (MKV) and Micro Satellite Systems (MSS) with an emphasis in reducing weight and cost but without affecting performance. Reducing the weight seems practical when reducing the size of the propulsion system, but problems are encountered with system design.

In addition, propulsion requirements strongly influence choice in propellant and complexity. A thorough understanding of stabilizing thrust levels and the ability to control the propulsion system …

A Variational Approach To Non-Newtonian Flow In Angular Pores: An Application To Enchanced Oil Recovery, Nithin Kavoori

Open Access Theses & Dissertations

With an alarming rise in carbon dioxide (CO2) emission from anthropogenic sources, CO2 sequestration has become an attractive choice to mitigate the emission. Some popular storage media for CO2 are oil reservoirs, deep coal-bed, deep oceanic-beds. These have been used for the long term CO2 storage. Due to special lowering viscosity and surface tension property of CO2, it has been widely used for enhanced oil recovery. The sites for CO2 sequestration or enhanced oil recovery mostly consist of porous rocks. In this thesis work, I focus on understanding the flow through porous at pore-level using variational approach.

Variational approach is …

Computational Study Of Fluid-Valve Interaction Involving Deep Vein Thrombosis, Upendra Parimi

Open Access Theses & Dissertations

The venous valves in veins carry on the important function of eliminating the retrograde (re-verse) flow of blood in veins and help the veins to carry on their work effectively. The abnormal functioning of venous valves can cause deep vein thrombosis (DVT) which is a phenomena caused by clotting in deep veins. The importance of the thesis work lies in understanding the role of blood flow dynamics in Deep Vein Thrombosis (DVT). Elderly People and pregnant women are the ones who are most likely to develop DVT. It was determined from previous studies that women in their postpartum period are …