Engineering Commons^™

Control Of Turbulent Flow Over An Articulating Turret For Reduction Of Adverse Aero-Optic Effects, Ryan Wallace

Mechanical and Aerospace Engineering - Dissertations

Turbulent flows such as wakes and shear layers are highly detrimental to the intensity of any collimated light beams that pass through these regions. The work presented in this thesis utilized suction flow control to help mitigate the adverse affects of the wake and shear layer over a flat aperture on the hemisphere of a three dimensional turret. The hemisphere of the turret was capable of dynamically articulating in two degrees of freedom: pitch and azimuthal rotation. The experiments were performed in the Syracuse University wind tunnel at a Mach number of 0.1, giving a Reynolds number of 500,000. Steady …

Issues On Clean Diesel Combustion Technology Using Supercritical Fluids: Thermophysical Properties And Thermal Stability Of Diesel Fuel, Ronghong Lin

Biomedical and Chemical Engineering - Dissertations

The clean diesel combustion technology using supercritical fluids is aimed to both improve fuel economy and reduce harmful emissions. This novel process involves preparation, injection and combustion of supercritical fuel/diluents mixtures. Design and development of this new process require a deep understanding of fuel properties. The current study has attempted to address three fuel property related issues: fuel surrogates, diffusivity and thermal stability.

Fuel surrogates are often used in engine research to mimic real fuel properties. In this work, ten diesel fuel surrogates were investigated, and the ability of these surrogates to predict diesel fuel properties was evaluated. It was …

Network-Aware Active Wardens In Ipv6, Grzegorz Lewandowski

Electrical Engineering and Computer Science - Dissertations

Every day the world grows more and more dependent on digital communication. Technologies like e-mail or the World Wide Web that not so long ago were considered experimental, have first become accepted and then indispensable tools of everyday life. New communication technologies built on top of the existing ones continuously race to provide newer and better functionality. Even established communication media like books, radio, or television have become digital in an effort to avoid extinction. In this torrent of digital communication a constant struggle takes place. On one hand, people, organizations, companies and countries attempt to control the ongoing communications …

Towards An Information Theoretic Framework For Evolutionary Learning, Stuart William Card

Electrical Engineering and Computer Science - Dissertations

The vital essence of evolutionary learning consists of information flows between the environment and the entities differentially surviving and reproducing therein. Gain or loss of information in individuals and populations due to evolutionary steps should be considered in evolutionary algorithm theory and practice. Information theory has rarely been applied to evolutionary computation - a lacuna that this dissertation addresses, with an emphasis on objectively and explicitly evaluating the ensemble models implicit in evolutionary learning. Information theoretic functionals can provide objective, justifiable, general, computable, commensurate measures of fitness and diversity.

We identify information transmission channels implicit in evolutionary learning. We define …

Comparison Of Silicon-On-Insulator And Body-On-Insulator Finfet Based Digital Circuits With Consideration On Self-Heating Effects, Peijie Feng, Prasanta Ghosh

Electrical Engineering and Computer Science - All Scholarship

In summary, we have compared SOI and BOI FinFET device characteristics and the performance of digital circuits designed with those devices. For low voltage supply, SHE is modest in both devices and during digital circuit operations. SOI FinFET CMOS inverter and SRAM cell characteristics are very similar to BOI ones. Considering the lesser fabrication complexity, SOI FinFET thus would be more preferable than BOI FinFET for the design of low voltage digital circuits.

A Biomimic Self-Healing Shape Memory Polymer Based Syntactic Foam For Smart Structural Composites, Jones Nji

LSU Doctoral Dissertations

This study explored the development of a new self-healing Polystyrene Shape Memory Polymer (PSMP) based syntactic foam for service life extension in structural polymeric composites. The objective was to self-heal structural-length scale damage in an autonomous, efficient, timely and repeatable manner at the molecular-length scale. Self-healing is achieved through a novel two step close-then-heal (CTH) self-healing scheme, designed to mimic the natural biological process of wound healing in humans. A new methodology to fabricate three-dimensional (3-D) fiber reinforced shape memory polymer syntactic foam for structural applications was developed. The effect of impact energy on the ability for the 3-D fiber …

Decoupling User Interface Design Using Libraries Of Reusable Components, Rajesh Sankaran

LSU Doctoral Dissertations

The integration of electronic and mechanical hardware, software and interaction design presents a challenging design space for researchers developing physical user interfaces and interactive artifacts. Currently in the academic research community, physical user interfaces and interactive artifacts are predominantly designed and prototyped either as one-off instances from the ground up, or using functionally rich hardware toolkits and prototyping systems. During this prototyping phase, undertaking an integral design of the interface or interactive artifact’s electronic hardware is frequently constraining due to the tight couplings between the different design realms and the typical need for iterations as the design matures. Several current …

Evaluation Of A Stream‐Aquifer Analysis Test For Deriving Reach‐Scale Streambed Conductance, Garey A. Fox, Derek M. Heeren, Michael A. Kizer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Extracting groundwater from pumping wells located adjacent to streams can reduce streamflow, a result that is known as alluvial well depletion. Numerous analytical solutions have been developed for alluvial well depletion that vary in their mathematical complexity. Predicted drawdown by the analytical solutions can be matched to observed drawdown from a stream–aquifer analysis (SAA) test (i.e., a pumping test adjacent to a stream) to simultaneously estimate aquifer and streambed hydrologic parameters. However, only a few SAA tests have been documented in the literature and compared to field–measured streambed parameters. Therefore, the objective of this research was to perform an SAA …

Characterization Of Room Temperature Terahertz Direct Detectors, Carla Renee Boggs

Browse all Theses and Dissertations

Room temperature direct detectors operating in the so-called Terahertz (THz) region of the electromagnetic spectrum, and representing the most common detection technologies currently available, were characterized at 104, 280 GHz or 600 GHz within their intended range of operating frequencies. These detectors included commercial Schottky-diode rectifiers (Virginia Diodes and Spacek Labs), commercial pyroelectric detectors (Spectrum Detector), and a commercial Golay cell (QMCI). The characterization included antenna patterns, responsivity, electrical noise, noise equivalent temperature difference (NEΔT ), and noise equivalent power (NEP). Since all the characterization measurements were made the same way, quantitative comparisons can be made between the performances of …

Efficient Risk Assessment Using Probability Of Fracture Nomographs, Venkateswaran Shanmugam

Browse all Theses and Dissertations

The traditional risk-based design processes involve designing the structure based on risk estimates obtained during several iterations of an optimization routine. This approach is computationally expensive for large-scale aircraft structural systems because of the iterative nature of the risk assessment methods. Therefore, this research introduces the concept of risk-based design plots that can be used for both structural sizing and risk assessment of stiffened plates when maximum allowable crack length information is available. These plots are obtained using normalized probability density functions of load and material properties and are applicable for any arbitrary load and strength magnitudes that follow similar …

Drag Reduction Of A Modern Straight Truck, Drew Landman, Matthew Cragun, Mike Mccormick, Richard Wood

Mechanical & Aerospace Engineering Faculty Publications

A wind tunnel test program was conducted at the Langley Full Scale Tunnel (LFST) to evaluate the performance of five passive drag reduction configurations on a modern straight truck at full scale. Configurations were tested in a build-up fashion with results representing a cumulative effect. Tested configurations include a front valance, a front box fairing, a boat-tail, an ideal side-skirt, and a practical side-skirt. Configurations were evaluated over a nominal 9 degree yaw sweep to establish wind averaged drag coefficients using SAE J1252. Genuine replicate yaw sweeps were used in an uncertainty analysis. Results show up to 28% improvement in …

An Investigation Into The Effect Of Blood Glucose Level Changes On Lf/Hf Parameter Of Hrv Signal In Non-Diabetic And Diabetic Individuals, Reza M. Amanipour

Open Access Theses & Dissertations

The analysis of time duration between consecutive R waves of electrocardiogram (ECG) is a standard method to evaluate the variations in heart rate. The physiological literature reveals that blood glucose levels modulate the autonomic nervous system (ANS) activity and heart rate variability (HRV) is representative of the cardiovascular autonomic function. In the research, an investigation was carried out to investigate the relationship between HRV signal measures derived from ECG and arterial blood glucose changes in five non-diabetic and five diabetic individuals during normoglycemic and mildly hyperglycemic conditions. A CleveLabs BioCapture wireless device was used to acquire ECG signals from ten …

Separation Of Humic Matter From Groundwater Via Anion Exchange Resin: Comparison Of Bead And Powder Form, Sandra June Everett

Open Access Theses & Dissertations

This work describes a comparison of a bead and powder form of anion exchange resin for removing humic matter from groundwater. The materials and procedures described herein involve a manufactured dry humic matter and two forms of the same anion exchange resin. Spectroscopy was the chosen procedure for analysis of organics.

Preliminary experiments were required to gain a better understanding of the materials and to prepare the best conditions for actual experimental research. Five concentrations of humic acid were used for experimental purposes at 0.5, 1, 5, 10 and 20 mg/L. Three concentrations of resin were used: 500, 750 and …

Development Of A New Evolutionary Algorithm Based On Adaptive Echolocation Applied To A Multi Objective Version Of The Redundancy Allocation Problem, Karla Rocio Gutierrez

Open Access Theses & Dissertations

The intention of this research is to develop a new algorithm that it is mainly focus in the principle of echolocation or also called biosonar. This principle is active in many animals such as: birds, shrews, dolphins and bats, these last ones are going to be a fundamental part of our study. These animals use it as radar in order to find food, obstacles or just to locate objects.

These animals use ultrasound beams with a certain degree of angle and multiple receivers; such as the two ears that are located slightly apart, so at the time of the returning …

Solving The Partial Differential Equation Of Vibrations With Interval Parameters Using The Interval Finite Difference Method, Brenda G. Medina

Open Access Theses & Dissertations

Accuracy and efficiency are among the main factors that drive today's innovative disciplines. As technology rapidly advances, efficiency takes on new meanings but what about accuracy? How accurate is accurate? Human error, uncertainties in measurement, and rounding errors are just some causes of inaccuracy. Interval Computations is an area that allows for such issues to be taken into account; for each measurement attained (for example), an interval can be built by considering the error associated with the measurement, and such an interval can be utilized in the mathematical computations of interest.

We consider the partial differential equation (PDE) of vibrations …

Evaluation Methods For Health Monitoring Of Aerospace Structure Rotary Joints, Sergio Armando Navarro

Open Access Theses & Dissertations

In September 2007, the excessive vibrations played a significant role in the station operation since one of the rotary joints, which provides the station electrical energy, presented an anomaly. The replacement of its bearing components and re-lubrication were necessary to reduce the problem. To avoid a new anomaly, the inspection of the rotary joints performance continues by using the accelerometers data. This thesis presents three new approaches to monitor the vibrations at the International Space Station based on Root-Mean-Square, kurtosis, and Approximate Entropy (ApEn). MATLAB functions and codes were necessary to implement the three monitoring techniques results from the provided …

Aether, Thomas Cameron, Kristine Colton, Daren Childers

Electrical Engineering

Aether is a RC-style autonomous air vehicle that utilizes GPS positioning along with a wireless communication system to achieve a computer-controlled flight.

This report will incorporate the acquisition, design, integration, implementation and testing phases of the UAV development. Furthermore a discussion of troubleshooting as well as improvements for future projects will be included.

Wireless Energy Transfer, Ryan Sasur

Electrical Engineering

Phones are now an integral component in the daily lives of people. Smartphones give access to movies, internet, and even books. This versatility and increased use can also lead to a shorter battery life. A phone with video viewing capabilities will be a heavy load on the unit’s battery. With phones utilizing 3G and 4G technology, even heavier demands are placed on the battery. As technology improves even further to provide for a larger entertainment experience on the phone, this could also lead to further battery degradation if the current battery situation isn’t addressed. To have a fully operational phone …

Characterizing Wireless And Powerline Communication Channels With Applications To Smart Grid Networks, Sabih Guzelgoz

USF Tampa Graduate Theses and Dissertations

Smart grid aims at improving the efficiency, reliability, security, and quality of service (QoS) of the current electricity grid by exploiting the advances in communication and information technology. In parallel to size of the electricity grid, smart grid communication infrastructure should cover a very large geographical area that may extend from remote generation sites to densely populated residential regions and inside buildings, homes, and electricity-power-system environments. In such an extensive communication network, different communication technologies operating on different communication medium are likely to coexist. Among the communication technologies available, wireless and power line communication (PLC) based solutions are comparatively attractive …

Design Issues In Magnetic Field Coupled Array: Clock Structure, Fabrication Defects And Dipolar Coupling, Anita Kumari

USF Tampa Graduate Theses and Dissertations

Even though silicon technology is dominant today, the physics (quantum electron tunneling effect), design (power dissipation, wire delays) and the manufacturing (lithography resolution) limitations of CMOS technology are pushed towards the scaling end. These issues motivated us towards a new paradigm that contributes to a continued advancement in terms of performance, density, and cost. The magnetic field coupled computing (MFC) paradigm, which is one of the regimes where we leverage and utilize the neighbor interaction of the nanomagnets to order the single-domain magnetic cells to perform computational tasks. The most important and attractive features of this technology are: 1) room …

Magneto-Dielectric Polymer Nanocomposite Engineered Substrate For Rf And Microwave Antennas, Cesar A. Morales

USF Tampa Graduate Theses and Dissertations

This dissertation presents the first reported systematic investigation on the implementation of multilayer patch antennas over Fe3O4-based polymer nanocomposite (PNC) magneto-dielectric substrates. The PNC substrate is created by the monodispersion of Fe3O4 nanopthesiss, with mean size of 7.5nm, in a polymeric matrix of Polydimethylsiloxane (PDMS).

Recently, magneto-dielectric substrates have been proposed by several researchers as a means for decreasing the size and increasing the bandwidth of planar antennas. Nevertheless, factors such as high loss and diminished control over magnetic and dielectric properties have hindered the optimal performance of antennas. In addition, the incompatibility and elevated complexity prevents integration of conventional …

Evanescent Wave Coupling Using Different Subwavelength Gratings For A Mems Accelerometer, Al-Aakhir A. Rogers

USF Tampa Graduate Theses and Dissertations

A novel technique of coupling near-field evanescent waves by means of variable period subwavelength gratings (1.2 ìm and 1.0 ìm), using a 1.55 ìm infrared semiconductor laser is presented for the use of an optical MEMS accelerometer. The subwavelength gratings were fabricated on both glass and silicon substrates respectively.

Optical simulation of the subwavelength gratings was carried out to obtain the maximum coupling efficiency of the two subwavelength gratings; the grating thickness, grating width, and the grating separation were optimized. This was performed for both silicon and glass substrates.

The simulations were used to determine the total system noise, including …

Design, Synthesis And Test Of Reversible Circuits For Emerging Nanotechnologies, Himanshu Thapliyal

USF Tampa Graduate Theses and Dissertations

Reversible circuits are similar to conventional logic circuits except that they are built from reversible gates. In reversible gates, there is a unique, one-to-one mapping between the inputs and outputs, not the case with conventional logic. Also, reversible gates require constant ancilla inputs for reconfiguration of gate functions and garbage outputs that help in keeping reversibility. Reversible circuits hold promise in futuristic computing technologies like quantum computing, quantum dot cellular automata, DNA computing, optical computing, etc. Thus, it is important to minimize parameters such as ancilla and garbage bits, quantum cost and delay in the design of reversible circuits.

The …

Application Of The Tdma Technique Toward The Size And Charge Distribution Measurement Of Graphite, Gold, Palladium, And Silver Aerosols, Matthew Paul Simones

All Graduate Theses, Dissertations, and Other Capstone Projects

The knowledge of charge distributions among aerosol particles has been an important topic for many years because of the strong electrostatic interactions which can greatly influence aerosol transport and evolution. Theoretical models have been developed although experimental verification has been limited because of the difficulty in measuring charged aerosols. Recently a method utilizing a tandem differential mobility analyzer (TDMA) has been shown to be applicable toward measuring both the size and charge distributions of nanosized combustion aerosols. The goal of this work is on further exploration of this method toward the measurement of non-combustion aerosols and in particular those associated …

Perspectives On Quality Coordination And Assurance In Global Supply Chains, Ling Li, John N. Warfield

Information Technology & Decision Sciences Faculty Publications

The 2007 recall of Berko Electric Toe-Space Heaters made in the US, the recall of backpack blowers made in Japan, the recalls of toys and pet food produced in China have exposed the potential of global supply chain disruptions. This product recall storm leads to the issue of quality assurance in global supply chain management. Product recalls indicate that manufacturing companies are particularly vulnerable to ensure quality when they source via a global supply chain with poor visibility. Obviously, a supply chain cannot afford this kind of sourcing and supply structure that threatens the supply-chain integrity. This special issue on …

Quasi-Steady Capillarity-Driven Flows In Slender Containers With Interior Edges, Mark M. Weislogel, J. Alex Baker, Ryan M. Jenson

Mechanical and Materials Engineering Faculty Publications and Presentations

In the absence of significant body forces the passive manipulation of fluid interfacial flows is naturally achieved by control of the specific geometry and wetting properties of the system. Numerous 'microfluidic' systems on Earth and 'macrofluidic' systems aboard spacecraft routinely exploit such methods and the term ‘capillary fluidics’ is used to describe both length-scale limits. In this work a collection of analytic solutions is offered for passive and weakly forced flows where a bulk capillary liquid is slowly drained or supplied by a faster capillary flow along at least one interior edge of the container. The solutions are enabled by …

Numerical Study Of Drop Formation From Dripping To Jetting, Allouah Kadjo

Mechanical and Aerospace Engineering Theses - Archive

The formation of liquid droplet from a capillary tube has been examined using numerical simulations. The dimensions of the capillary tube and the flow velocity have been varied to observe the regimes of drop formation. There are three main regimes of drop formation, which are the periodic dripping, the dripping faucet and the jetting regimes. The mechanism of drop formation changes from one regime to another and involves different parameters. A particular emphasis has been placed on the velocity limits between the different regimes and the critical role played by instabilities in the generation of satellite drops. The algorithm used …

Numerical Modeling Of A Parallel Plate Electrowetting-On-Dielectric (Ewod) Device, Kevin Tully

Mechanical and Aerospace Engineering Theses - Archive

Numerical modeling and simulations have been performed in this study that focuses on modeling the fluid dynamics of an Electrowetting-on-Dielectric (EWOD) device. The case to be modeled in the present study is a droplet cutting problem where a droplet is sandwiched between two plates of Teflon and an electrical actuation will cause the droplet to cut or split into two smaller droplets. A finite difference method has been used to solve the Navier-Stokes equations, along with the continuity equation. An algorithm used for tracking the free surface is the Volume of Fluid (VOF) method. Along with using the VOF method …

Understanding The Influence Of Blog On The Development Of Social Capital, Reza Vaezi, Gholamreza Torkzadeh, Jerry Cha-Jan Chang

Management, Entrepreneurship and Technology Faculty Research

The rapid use and application of blogs in diverse areas such as education, marketing, journalism, and human resource management in recent years underlines the need for a better understanding of the impact of this new technology on social capital. Social capital reflects the norm of reciprocity and the level of trust among individuals who connect, interact, and benefit from one another. Blog is expected to influence the extent and the scope of this interaction by providing new means of networking among people. This paper examines the relationship between blog use and social capital and reports on the results of an …

Management Of Change To Ensure Is Success: A Longitudinal Study, Pauline Ash Ray, Wenli Wang, Jerry Cha-Jan Chang, Geoffrey Hubona

Management, Entrepreneurship and Technology Faculty Research

This paper aims to understand the effect of management of change on the success of information system (IS) implementation. Drawing on change management research and self-determination theory, a research model is developed. Data collected from a longitudinal field survey before, during, and after an enterprise-wide IS implementation are analyzed to test the proposed hypotheses. The results indicate that management of change can be used to increase readiness for change and end-user computing satisfaction during and after the implementation. Readiness for change positively impacts satisfaction during an implementation but not after. Contrary to the literature, No significant relationship exists between resistance …