Engineering Commons^™

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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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 …

Fabrication Of Superhydrophobic Polystyrene Surfaces With Tunable Adhesion By Modulating Strain Recovery Temperature, Prasha Sarwate

Mechanical and Aerospace Engineering Theses - Archive

In this work, different superhydrophobic structures were fabricated on the surfaces of polystyrene (PS) blocks, using oxygen reactive ion etch (ORIE) and controllable strain recovery. The PS used here is a thermal shape memory polymer (SMP). Microhills are first generated on the surface of a PS block by ORIE. The PS block is then heated up, which triggers the strain recovery. During this process of recovering its original shape, the PS block gradually reduces its lateral dimensions, while increasing its thickness. Using different recovery temperatures, the surface morphologies can be controlled, which provides an approach to adjust surface wetting properties, …

Rfbr: Radio Frequency Beacon Receiver, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

The Space Dynamics Laboratory at Utah State University (SDL/USU), the Air Force Space and Missile Systems Center (SMC), and the Air Force Research Laboratory (AFRL) have teamed together to provide a portable ground-based radio frequency beacon receiver (RFBR) system capable of characterizing ionospheric parameters, including total electron content (TEC), amplitude, and phase scintillation. The system, derived almost entirely of COTS parts, can be configured to receive RF beacons such as those transmitted by existing on-orbit Coherent Electromagnetic Radio Tomography (CERTO) instrumentation, the upcoming Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC2), or other frequencies from VHF to S-band. By …

Comparative Analysis Of Gps Data, Kiel Von Lindenberg

Undergraduate Journal of Mathematical Modeling: One + Two

The goal of this project is to calculate the distance traveled during a bike ride around the University of South Florida using information gathered by a GPS (Global Positioning System) application on a smartphone. We calculate the route distance in two ways: from latitudes and longitudes using the haversine formula and 2) from velocities and times using the trapezoidal rule. These computed distances were compared to the distance given by the smartphone application.

Rocket Flight Path, Jamie Waters

Undergraduate Journal of Mathematical Modeling: One + Two

This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

Tacot V3.0, Jean Lachaud, Tom Van Eekelen, Daniele Bianchi, Alexandre Martin

Ablation Workshop: Code Comparison

No abstract provided.

Nonlinear Development And Secondary Instability Of Traveling Crossflow Vortices, Fei Li, Meelan M. Choudhari, Lian Duan, Chau-Lyan Chang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Building upon the prior research targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration, this paper investigates the secondary instability of traveling crossflow modes as an alternate scenario for transition. For the parameter range investigated herein, this alternate scenario is shown to be viable unless the initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by considerably more than one order of magnitude. The linear growth predictions based on the secondary instability theory are found to agree well with both parabolized stability equations and direct numerical simulation, and the …

Active-Passive Networked Multiagent Systems, Tansel Yucelen, John Daniel Peterson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper introduces an active-passive networked multiagent system framework, which consists of agents subject to exogenous inputs (active agents) and agents without any inputs (passive agents) and analyze its convergence using Lyapunov stability. Apart from the existing relevant literature, where either none of the agents are subject to exogenous inputs (i.e., average consensus problem) or all agents are subject to these inputs (i.e., dynamic average consensus problem), the key feature of our approach is that the states of all agents converge to the average of the exogenous inputs applied only to the active agents, where these inputs may or may …

Verifiable Frequency-Limited Adaptive Control Performance Based On Linear Matrix Inequalities, Mario Luca Fravolini, Tansel Yucelen, Daniel Wagner, Ali Albattat, Paolo Valigi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Adaptive controllers are often criticized for the lack of clear and easy verification procedures that relate design parameters to time domain performance especially during transients. For this reason, it is a challenge to rigorously certify existing adaptive control algorithms. To that end, we propose a validation framework where stability and performance requirements are formulated in terms of Linear Matrix Inequalities. This brings the advantage that adaptive controller design and verification can be analyzed and optimized via the solution of a convex optimization whose objective is to guarantee the evolution of the error components within an a-priori specified domain. This approach …

Radical Species Generation And Their Lifetime Extension By A Femtosecond And Nanosecond Dual-Laser System, Cheng Hsiang Lin, Zhi Liang, Jun Zhou, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

For Many Material Processes, Desired Radical Species at Excited States Are Produced Which Interact with a Given Substrate for a Certain Period of Time Allowing Chemical Reactions between Them to Occur and Complete. Hence, It is Important to Maintain the Population of the Excited Radical Species for an Extended Period of Time, I.e., their Lifetime, Which is Defined as the Time for Emission Intensity to Decay to 1/e of the Initial Intensity. in This Study, a Femtosecond-Nanosecond (Fs-Ns) Dual-Laser System Was Employed to Generate Desired Radical Species Via the Fs Laser And, Then, to Extend the Lifetime of the Radical …

Extremum-Seeking For Nonlinear Discrete-Time Systems With Application To Hcci Engines, H. Zargarzadeh, S. Jagannathan, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

For many control applications, identifying an optimal operating point by maximizing/minimizing a performance function is important. This paper applies the extremum-seeking method to nonaffine, nonlinear discrete-time systems stabilized by an optimal adaptive controller. First, a novel averaging method is used for the nonlinear discrete-time systems to show that their output unique extrema are stable equilibrium points. Then, a singular perturbation method in discrete time is employed to show that the overall closed loop system will dynamically converge to the extremum. The applicability of this scheme is numerically verified on a Homogeneous Charge Compression Ignition (HCCI) model validated experimentally and expressed …

Analysis And Implementation Of Pm Sampling Methodology Protocols To Aid In The Development Of An Arp (Aerospace Recommended Practice) For Aircraft Non-Volatile Pm Measurements, Brian Lowell Catron

Masters Theses

"Due to the growing concerns that particulate matter (PM) have on health and the environment, there is a need to include mass and number non-volatile PM measurements to current jet engine certification. This thesis looks at the necessary work required to help produce recommendations and perform background research to aid in the creation of an improved Aerospace Recommended Practice (ARP) (by the SAE E-31 Committee). This work addressed the following issues. The investigation began in the Missouri S&T Center of Excellence for Aerospace Particulate Emissions Reduction Research (COE) laboratory with an examination of the jet engine surrogate used, the miniCAST, …

Fabrication Of Glass Fiber-Reinforced Transparent Composites Using Vacuum Assisted Resin Transfer Molding Process, Gregory A. Taylor

Masters Theses

"The most commonly used transparent material is glass. Traditionally, glass is not desired for applications involving a low weight material while preserving high strength such as aerospace and military applications where armor must also be transparent. Some applications may include aircraft canopies and other vehicle windows. Development of a reliable transparent composite would fill a need for many of these applications where a transparent structure must both be strong and lightweight. A transparent polymer reinforced with a glass fiber fabric is a viable solution. To ensure transparency, both fiber and matrix must match in refractive index.

In the present work, …

The Effect Of Different Rollover Conditions Of The Vibrator On Human Injury, Qin Li, Hang Liu, Zhiqiang Huang, Yaping Ding, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Vibrator, as a crucial vehicle of oil and gas exploration, is challenged by the complex terrains. The probability of rollover accident is therefore high in bumpy terrain in which the drivers' life is seriously threatened. Finite element numerical analysis was used to study the injury of the driver's head, neck and chest in the rollover accidents of domestic KZ-28 type vibrator on different conditions. The injuries of three parts were evaluated based on the human injury criteria. Driver's safety on different rollover conditions was comparatively analyzed. The results indicated that the injury degree of human head caused by vibrator rollover …

Adaptive Control Of Uncertain Systems With Gain Scheduled Reference Models, Mehrdad Pakmehr, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper develops a new model reference adaptive control approach for uncertain systems with gain scheduled reference models in a multi-input multi-output (MIMO) setting. Specifically, adaptive state feedback for output tracking control problem of MIMO nonlinear systems is studied and gain scheduled reference model system is used for generating desired state trajectories. Using convex optimization tools, a single Lyapunov matrix is computed for multiple linearization's near equilibrium and non-equilibrium points of the nonlinear closed loop gain scheduled reference system. This approach guarantees stability of the closed loop gain scheduled system. Adaptive state feedback control scheme is then developed, and its …