Microwave-Based Navigation Of Femtosatellites Using On-Off Keying,
2014
University of Texas at Arlington
Microwave-Based Navigation Of Femtosatellites Using On-Off Keying, Namrata J. Kamte
Mechanical and Aerospace Engineering Theses - Archive
The objective of this research is to validate that a custom-built microchip-scale satellite transmitting a signal modulated with a Pseudo Random Noise code using On-Off Keying, can be tracked. The weak GPS satellite signal is modulated with a Pseudo Random Noise (PRN) code that provides a mathematical gain. Our signal is modulated with the same PRN code using On-Off Keying (OOK) unlike Phase Shift Keying used in GPS satellites. Our goal is to obtain timing and positioning information from the microchip-scale satellite via a ground station using the concepts of PRN encoding and the OOK modulation technique.Decimeter scale satellites, with …
Use Of Nanoparticle Enhanced Phase Change Material (Nepcm) For Data Center Cooling Application,
2014
University of Texas at Arlington
Use Of Nanoparticle Enhanced Phase Change Material (Nepcm) For Data Center Cooling Application, Harshal Gujarathi
Mechanical and Aerospace Engineering Theses - Archive
This study attempts to take advantage of nanoparticles with high thermal conductivity and the latent heat capacity of phase change materials together to enhance heat transfer rate. The main difficulty in using PCM for energy application is its low thermal conductivity in solid state. So, when solidification starts it makes it hard for evacuation of energy. A paraffin-based nanoparticle containing various volume fractions of Cu was applied. The suspended nanoparticles caused an increase in thermal conductivity of nanoparticles enhanced phase change material (NEPCM) compared to conventional PCM, resulting in heat transfer enhancement and a higher melting rate. The higher temperature …
Improving Air Cooling Efficiency Of 2ou High-End Web Server By Using Bigger Rack Level Fans And Controlling Flow Using Bimetallic Strips,
2014
University of Texas at Arlington
Improving Air Cooling Efficiency Of 2ou High-End Web Server By Using Bigger Rack Level Fans And Controlling Flow Using Bimetallic Strips, Ravi Teja Mutyala
Mechanical and Aerospace Engineering Theses - Archive
Due to the doubling of processing power ever so often, designing an efficient thermal management system for database centers is becoming more and more difficult. Two studies have been done, one on air cooling using bigger rack level fans and another in liquid cooling minimizing the size of flow control devices. Fans are one of the most inefficient and power hungry devices used in an air cooled database center. Study has been done to improve the air cooling efficiency using larger rack level fans on 2OU open compute server. Simulations have been done using commercial computational fluid dynamic (CFD) software …
Composite Materials Equivalent Properties In Lamina, Laminate, And Structure Levels,
2014
University of Texas at Arlington
Composite Materials Equivalent Properties In Lamina, Laminate, And Structure Levels, Kamran Tavakoldavani
Mechanical and Aerospace Engineering Theses - Archive
Increasing use of thick composite structures requires a large model for structural analysis. In the analysis, equivalent properties of composites are often used. The equivalent properties of a composite are defined as the properties of a homogeneous orthotropic composite to representative an anisotropic heterogeneous composite material.A set of equations for equivalent mechanical and thermal properties in lamina and laminate as well as structures was developed. The developed model for lamina and laminate of composite was based upon the equivalent structural characteristics of 0? lamina and homogenized 0? laminate for lamina and laminate level, respectively. The concept of narrow beam was …
Evaluating Heat Sink Performance In An Immersion-Cooled Server System,
2014
University of Texas at Arlington
Evaluating Heat Sink Performance In An Immersion-Cooled Server System, Trevor Dean Mcwilliams
Mechanical and Aerospace Engineering Theses - Archive
As operating power within server systems continues to increase in support of increased data usage across networks worldwide, it is necessary to explore options outside of traditional air-cooled systems. In this study, a specific server will be immersed and cooled using circulated mineral oil. The challenges associated with an emerging cooling technology are numerous. Trying to adapt existing air-cooled systems into oil-cooled systems has its difficulties. The viscous properties of oil make it resistive to traveling through the narrow fins of a conventional heat sink, and thermal mixing is not easy to achieve as it is in air due to …
Optimal Design Variable Considerations In The Use Of Phase Change Materials In Indirect Evaporative Cooling,
2014
University of Texas at Arlington
Optimal Design Variable Considerations In The Use Of Phase Change Materials In Indirect Evaporative Cooling, Ankit Paul Chilakapaty
Mechanical and Aerospace Engineering Theses - Archive
The demand for sustainable, energy efficient and cost effective heating and cooling solutions is exponentially increasing with the rapid advancement of computation and information technology. Use of latent heat storage materials also known as phase change materials (PCMs) for load leveling is an innovative solution to the data center cooling demands. These materials are commercially available in the form of microcapsules dispersed in water, referred to as the microencapsulated phase change slurries and have higher heat capacity than water. The composition and physical properties of phase change slurries play significant role in energy efficiency of the cooling systems designed implementing …
Modeling And Simulation Of Nanofluid For Heat Storage,
2014
University of Texas at Arlington
Modeling And Simulation Of Nanofluid For Heat Storage, Yatish Nagaraj
Mechanical and Aerospace Engineering Theses - Archive
This work models the dynamic behavior of molten nitrate salt mixture to investigate the formation of interfacial nanostructures in ionic liquid nano-fluids which is responsible for increase of heat capacity of the mixture. A key application of these fluids is in heat storage in solar collector where the heat capacity determines the amount of energy storage and therefore the efficiency of a solar collector system. The heat capacity can be significantly increased by the addition of a small amount of nanoparticles, of radius 1 to 100 nanometers in a concentration of approximately 1 by weight. This increase appears to be …
Experimental Testbed For Robot Skin Characterization And Interaction Control,
2014
University of Texas at Arlington
Experimental Testbed For Robot Skin Characterization And Interaction Control, Kyle Shook
Mechanical and Aerospace Engineering Theses - Archive
This thesis presents the research and work we conducted with an experimental testbed designed for testing and characterizing various types of robot skin with tactile sensing. The main goal of this research is to develop reduced-order models of robot skin for use in physical human-robot interaction simulations. The reduced-order models are developed from data collected by the testbed. The experimental testbed presented is designed around a National Instruments compactRIO (cRIO). The cRIO controls and reads from a linear actuator and can collect synchronous measurements from multiple force sensors. The software developed for different test scenarios is also presented. Experiments were …
Multi-Variable Design Optimization Of A Contemporary Cold Plate For A Fixed Pumping Power For Minimizing The Thermal Resistance,
2014
University of Texas at Arlington
Multi-Variable Design Optimization Of A Contemporary Cold Plate For A Fixed Pumping Power For Minimizing The Thermal Resistance, Pratik Kekre
Mechanical and Aerospace Engineering Theses - Archive
Due to reliability concerns, thermal management of microprocessors has and continues to become a major challenge in electronic packaging. High circuit densities in modern integrated circuit semiconductor devices require the heat generated by their operation be efficiently removed, in order to maintain the temperatures of the device within limits which will consequently follow the design guideline for operating parameters.Air-cooling is still the preferred method of cooling electronic systems and especially in terms of cost. Air cooling, however, is starting to reach its limits for some of the higher end electronic systems and as such there is a need to investigate …
Board Level Reliability Assessment Of Thick Fr-4 Qfn Assemblies Under Thermal Cycling,
2014
University of Texas at Arlington
Board Level Reliability Assessment Of Thick Fr-4 Qfn Assemblies Under Thermal Cycling, Tejas Shetty
Mechanical and Aerospace Engineering Theses - Archive
Quad Flat No-Lead (QFN) packages gained popularity in the industry during the last decade or so due to its superior thermal/electrical characteristics, low cost and compact size. QFN packages are widely used in handheld devices where space is a constraint; however, some customers require it for industry application demanding thicker printed circuit boards (PCB's). As the thickness of PCB increases, the fatigue life (MTTF) of the solder joints decreases. QFN being a leadless package, its board level thermo-mechanical reliability is a critical issue. This provides the motivation for this work. The QFN package on thick board was experimentally characterized under …
Computational Analysis Of A Multistage Axial Compressor,
2014
University of Texas at Arlington
Computational Analysis Of A Multistage Axial Compressor, Chaithanya Mamidoju
Mechanical and Aerospace Engineering Theses - Archive
Turbo machines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed …
Reduced Order Modeling Of Low-Temperature Gas Discharges In Glow Mode,
2014
University of Texas at Arlington
Reduced Order Modeling Of Low-Temperature Gas Discharges In Glow Mode, Esteban Cisneros
Mechanical and Aerospace Engineering Theses - Archive
Gas discharge actuation of fluid dynamics phenomena has garnered significantattention in recent years due to their low-power requirements andtheir geometrical simplicity, amongst others. However, many of their actuationmechanisms and physical couplings are still not well-understood,calling for numerical efforts to address many of theseproblems. Modeling and simulation of plasma-flow interaction is anexhaustive task because of the multi-physics, multi-scale nature ofthe problem. One particular concern is the appropriate modeling of thedischarge detailed chemistry in order to reduce the computationalcost associated with it while capturing all of its finest features. \\Modern reduction techniques attempt to create reduced-order models ofchemical kinetics by identifying low-dimensional …
Development Of A Conceptual Design Weight Estimation Method Library And Documentation,
2014
University of Texas at Arlington
Development Of A Conceptual Design Weight Estimation Method Library And Documentation, Andrew S. Walker
Mechanical and Aerospace Engineering Theses - Archive
The state of the art in estimating the volumetric size and mass of flight vehicles is held today by an elite group of engineers in the Aerospace Conceptual Design Industry. This is not a skill readily accessible or taught in academia. To estimate flight vehicle mass properties, many aerospace engineering students are encouraged to read the latest design textbooks, learn how to use a few basic statistical equations, and plunge into the details of parametric mass properties analysis. Specifications for and a prototype of a standardized engineering "tool-box" of conceptual and preliminary design weight estimation methods were developed to manage …
Dynamic Simulation Of Multibody Systems In Simultaneous, Indeterminate Contact And Impact With Friction,
2014
University of Texas at Arlington
Dynamic Simulation Of Multibody Systems In Simultaneous, Indeterminate Contact And Impact With Friction, Adrian Rodriguez
Mechanical and Aerospace Engineering Dissertations - Archive
This research is focused on improving the solutions obtained using theory in contact and impact modeling. A theoretical framework is developed which can simulate the performance of dynamic systems within a real world environment. This environment involves conditions, such as contact, impact and friction. Numerical simulation provides an easy way to perform numerous iterations with varying conditions, which is more cost effective than building equivalent experimental setups. The developed framework will serve as a tool for engineers and scientists to gain some insight on predicting how a system may behave. The current field of research in multibody system dynamics lacks …
Design And Fabrication Of Microfluidic Photoelectrochemical Reactors For Efficient Conversion Of Carbon Dioxide To Liquid Fuel,
2014
University of Texas at Arlington
Design And Fabrication Of Microfluidic Photoelectrochemical Reactors For Efficient Conversion Of Carbon Dioxide To Liquid Fuel, Homayon Homayoni
Mechanical and Aerospace Engineering Dissertations - Archive
The world's energy demand is expected to increase dramatically over the next few decades. At the same time the availability of cheap fossil fuels is expected to decrease. In addition to the increase in energy cost, the use of fossil fuels results in the release of greenhouse gases into the atmosphere. A lot research effort has been invested in the development of renewable energy resources that are cost competitive, sustainable, and emission free. Although these renewable technologies are available, many are not implemented widely due low efficiency and high capital cost. Therefore, fossil fuels are expected to remain a major …
Enhancement Of Pool Boiling And Evaporative Heat Transfer Using High Temperature Thermally Conductive Microporous Coatings,
2014
University of Texas at Arlington
Enhancement Of Pool Boiling And Evaporative Heat Transfer Using High Temperature Thermally Conductive Microporous Coatings, Ajay Gurung
Mechanical and Aerospace Engineering Dissertations - Archive
The present research is an experimental study of the enhancement of pool boiling and evaporative heat transfer using high temperature thermally conductive microporous coatings. Two major types of coatings were investigated: one that is based on copper powders on copper substrate and the other on aluminum powders on aluminum substrate. Both coatings were easy to fabricate with low costs compared to conventional sintering and plasma spraying techniques, yet have high bonding strength and some of them can operate at temperatures up to 670 oC. Multiple coating options were fabricated and tested in pool boiling of water in order to optimize …
Experimental Study Of Separated Ramp-Induced Shock/Boundary-Layer Interaction With Upstream Micro-Vortex Generator At Mach 2.5,
2014
University of Texas at Arlington
Experimental Study Of Separated Ramp-Induced Shock/Boundary-Layer Interaction With Upstream Micro-Vortex Generator At Mach 2.5, Yusi Shih
Mechanical and Aerospace Engineering Dissertations - Archive
Shock wave/boundary layer interactions (SBLIs) are important issues for high-speed vehicles. SBLIs reduce the performance of aerodynamic surfaces and engine inlets, amongst a number of adverse effects. Micro-vortex generators (MVGs) are a flow control method with strong potential to mitigate the effects of SBLI by energizing the boundary layer through momentum transfers from the freestream. They have been implemented in actual configurations at low speeds. The present research includes a combined experimental and theoretical analysis of the evolution of the perturbation downstream the MVG, the formation of vortices, and their interaction with the shock front. Experiments were performed with a …
Analytical Solutions Of Steady-State Heat Conduction In Multi-Layer Stack Packaging,
2014
University of Texas at Arlington
Analytical Solutions Of Steady-State Heat Conduction In Multi-Layer Stack Packaging, Saeed Ghalambor
Mechanical and Aerospace Engineering Dissertations - Archive
Analytical models that can be utilized in modeling the steady-state temperature solutions of planar and 3D packaged integrated circuits are discussed. This mathematically-driven model will include solutions for uniform and non-uniform footprint die stack systems as well as planar flip chip packages. These analytically obtained temperature solutions will include the contribution of thermal resistance for both cases as well as perfect contact scenarios. The acquired solution will accommodate any kind of boundary conditions (first, second and third kind) on the top and bottom surfaces of the stack system with the sides being adiabatic. Furthermore, the algorithm developed will consider volumetric …
Computational Analysis Of Nanostructures Formed In Molten Salt Nanofluids,
2014
University of Texas at Arlington
Computational Analysis Of Nanostructures Formed In Molten Salt Nanofluids, Vidula B. Pawar
Mechanical and Aerospace Engineering Theses - Archive
Meeting the continuously increasing demand of `clean' energy is the biggest challenge of the energy research field. Amongst the many renewable sources of energy, energy from the Sun is one of the biggest sources in the form of light and heat. Photovoltaic cells and concentrated solar power are few of the solar energy harnessing technologies. Photovoltaic cells use semiconductor materials to directly convert energy from sun into electricity. CSP uses a combination of solar receivers (mirrors or lenses) to concentrate the solar thermal energy which is further converted into electricity using the common thermodynamic cycle. One of the Photovoltaic (PV) …
Thermo-Mechanical Feasibility Study Of Copper And Gold Wirebonds In 3d Electronic Package,
2014
University of Texas at Arlington
Thermo-Mechanical Feasibility Study Of Copper And Gold Wirebonds In 3d Electronic Package, Gaurang Naware
Mechanical and Aerospace Engineering Theses - Archive
3 Dimensional (3D) Electronics Packaging has emerged as a revolutionary trend in the micro-electronics industry. It has made possible cost-effective system integration and size scaling while reducing the interconnect delay. The ever increasing demand for better mechanical, thermal, electrical performance, improved reliability and cost effective semiconductor manufacturing technology has encouraged the engineers to replace Gold (Au) by Copper (Cu). In a survey conducted by Semiconductor Equipment and Materials International, to study the industry mood related to wirebond technology, it was observed that 72% of the leading semiconductor companies are considering switching to Cu [1]. The only major concern regarding the …
