Engineering Commons^™

Two-Dimensional Numerical Modeling Of A Proposed Freshwater Diversion From The Bonnet Carre Spillway To The Labranche Wetlands, Josef Patrick Hoffmann

LSU Master's Theses

Engineered modifications to the lower Mississippi River within the past century have limited the magnitude and frequency of flood events in wetlands along the Louisiana coast. Without this natural delivery of freshwater, sediment, and nutrients, the ecological health of these wetlands are now degrading. A recent study within the Bonnet Carre Spillway has revealed that the 7,623 acres of floodway between the Mississippi River and Lake Pontchartrain is one of the few areas in Louisiana that is actively accreting land as a result of pulsed sediment-laden freshwater input during high discharge events in the Mississippi River. On the other hand, …

A Semantic Agent Framework For Cyber-Physical Systems, Jing Lin, Sahra Sedigh, Ann K. Miller

Electrical and Computer Engineering Faculty Research & Creative Works

The development of accurate models for cyber-physical systems (CPSs) is hampered by the complexity of these systems, fundamental differences in the operation of cyber and physical components, and significant interdependencies among these components. Agent-based modeling shows promise in overcoming these challenges, due to the flexibility of software agents as autonomous and intelligent decision-making components. Semantic agent systems are even more capable, as the structure they provide facilitates the extraction of meaningful content from the data provided to the software agents. In this book chapter, we present a multi-agent model for a CPS, where the semantic capabilities are underpinned by sensor …

Direct Digital Frequency Synthesizer Architecture For Wireless Communication In 90 Nm Cmos Technology, Tri Trong Nguyen

Browse all Theses and Dissertations

Software radio is one promising field that can meet the demands for low cost, low power, and high speed electronic devices for wireless communication. At the heart of software radio is a programmable oscillator called a Direct Digital Synthesizer (DDS). DDS has the capabilities of rapid frequency hopping by digital software control while operating at very high frequencies and having sub-hertz resolution. Nevertheless, the digital-to-analog converter (DAC) and the read-only-memory (ROM) look-up table, building blocks of the DDS, prevent the DDS to be used in wireless communication because they introduce errors and noises to the DDS and their performances deteriorate …

Design Of A Low Power And Area Efficient Digital Down Converter And Sinc Filter In Cmos 90-Nm Technology, Steven John Billman

Browse all Theses and Dissertations

A digital down converter (DDC) typically receives a digital input that has been generated by an analog to digital converter (ADC) operating at intermediate frequency (IF) in an RF receiver chain. The function of the DDC is to down convert the IF signal to baseband in phase (I) and quadrature (Q) signals and is a very important component in wireless receivers. A Digital Down Converter (DDC) is developed based on square wave local oscillators facilitating a multiplier-less implementation with no constraints on the sampling frequency. The DDC includes a pseudo multi-rate SINC low pass filter which exhibits better performance compared …

Dynamic Control For A Pneumatic Muscle Actuator To Achieve Isokinetic Muscle Strengthening, Kara Lynn Hall

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A pneumatic muscle actuator (PMA) is a device that mimics behavior of skeletal muscle by contracting and generating force in a nonlinear manner when activated. PMAs have a high power to weight ratio and possess unique characteristics which make them ideal for human interaction. Due to their nonlinear dynamics, PMAs are difficult to control, presenting challenges in system implementation. Despite these challenges, PMAs have great potential as a source of resistance for strength training and rehabilitation. The main goal of this work was to control a PMA for use in isokinetic exercise, potentially benefiting anyone in need of optimal strength …

Influence Of Design Parameters On Cup-Stem Orientations For Impingement Free Range Of Motion In Hip Implants, Dishita Prakashbhai Patel

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The objective of this investigation is to determine the optimum positions of the prosthesis in total hip arthroplasty that produce least amount of impingement. Theoretical ranges of six basic hip motions were determined under walking, stumbling, internal rotation at 90 flexion and external rotation at 0 extension with 15 abduction, using mathematical models and validated for impingement using finite element analysis. A generalized approach, where impingement does not occur, was developed in this study to understand influence of design parameters such as head-neck ratio, neck-shaft angle, oscillation angle, and stem offset on cup-stem orientations such as cup inclination, cup anteversion, …

Structured Silicon Macropore As Anode In Lithium Ion Batteries, Xida Sun

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Porous silicon (PS) membranes for lithium-ion batteries (LIBs) anode applications were developed, demonstrated and characterized systematically in this work. Electrochemical measurements were conducted on both Si-wafer supported and free-standing porous Si membranes. It turned out that the specific capacity of LIBs was enhanced remarkably by PS based anode. PS was fabricated by using electrochemical anodization in a mixed solution of Dimethylformamide (DMF) and Hydrofluoric acid (HF wt.49%). By varying the anodization conditions, including HF concentration, anodization etching time and current density, pores were formed in a p-type (1-20Ω cm) boron-doped silicon substrate. Scanning electron microscopy (SEM) was employed to investigate …

A Validation Of A Prototype Dry Electrode System For Electroencephalography, Jason Monnin

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Current physiologically-driven operator cognitive state assessment technology relies primarily on electroencephalographic (EEG) signals. Traditionally, gel-based electrodes have been used; however, the application of gel-based electrodes on the scalp requires expertise and a considerable amount of preparation time. Additionally, discomfort can occur from the abrasion of the scalp during preparation, and the electrolyte will also begin to dry out over extended periods of time. These drawbacks have hindered the transition of operator state assessment technology into an operational environment. QUASAR, Inc., (San Diego, CA) has developed a prototype dry electrode system for electroencephalography that requires minimal preparation. A comparison of the …

Effects Of Large-Scale Transient Loading And Waste Heat Rejection On A Three Stream Variable Cycle Engine, Michael William Corbett

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The objective of the research presented in this document was to gain an understanding of the feasibility of extracting large amounts of transient shaft power from a variable cycle engine and to reject waste heat into the third stream bypass duct. This first required the development of a transient engine and controller simulation. After performing basic verification of the model, such as ensuring conservation of mass, tests were run for three missions using a low-efficiency periodic load which both required shaft power and created low quality waste heat. The waste heat generated by that load was lifted by a cooling …

Quantification Of Model-Form, Predictive, And Parametric Uncertainties In Simulation-Based Design, Matthew E. Riley

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Traditional uncertainty quantification techniques in simulation-based analysis and design focus upon on the quantification of parametric uncertainties-inherent natural variations of the input variables. This is done by developing a representation of the uncertainties in the parameters and then efficiently propagating this information through the modeling process to develop distributions or metrics regarding the output responses of interest. However, in problems with complex or newer modeling methodologies, the variabilities induced by the modeling process itself-known collectively as model-form and predictive uncertainty-can become a significant, if not greater source of uncertainty to the problem. As such, for efficient and accurate uncertainty measurements, …

Three Deadly Venoms: Phenomenology, Existentialism, And Philosophical Constructs To Expand Engineering Education Research Methodologies And Philosophy, George Dante Ricco

School of Engineering Education Graduate Student Series

The Engineer through a Multidisciplinary Lens Our work invokes multiple theoretical approaches to the question of the engineer’s perception of his/her place in the field of engineering through lenses within social psychology and modern philosophy. We aim to help augment current conversations on and further dialogue as to what engineering is from ethnomethodological (or existential phenomenological) and symbolic interactionism points of view. The foundation of our work is the current state of engineering and how to address the engineer’s negotiation of his/her state of affairs. We believe this work has strong implications amidst recent publications invoking epistemologies based upon modern …

Person-Thing Orientation As A Predictor Of Engineering Persistence And Success, Ida Ngambeki, Demetra Evangelou Dr, William Graziano, Diana N Bairaktarova, Sara E Branch, Anna Woodcock

School of Engineering Education Graduate Student Series

Interest, especially in the United States, is an important motivation for students in choosing a major and the strength of their commitment to remaining in that major. In the examination of engineering students’ reasons for persistence and success, interest has not received an in-depth treatment. Interest as a motivational factor can be characterized and operationalized in several ways. Engineering is often typified as a discipline that primarily deals with the creation and manipulation of man-made artefacts as opposed to a discipline centered on interpersonal interaction. For this study interest has been characterized along the Person-Thing dimension.This has been operationalized as …

Motivations And Benefits For College Students Serving As Mentors In A High School Robotics Competition, Noah Salzman, Johannes Strobel

School of Engineering Education Graduate Student Series

Many universities provide space for student organizations in which undergraduate students are learning leadership skills, mentor other students and bring their engineering skills to practice.Purdue FIRST Programs (PFP) is a service-learning program where university students mentor predominantly high school student teams participating in the FIRST Robotics Competition (FRC). Whereas most FRC teams are mentored by professional engineers, PFP is unique in both the extent which it relies on student mentors and the overall scope of the organization. Existing models of mentorship do not adequately describe the specific relationship between the college and high schools students: (1) Due to the proximity …

Handbook For Temporary Traffic Control - Construction, Maintenance, And Utility Operations, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This handbook gives the basic principles and provides examples for the design, application, installation, and maintenance of the various types of traffic control devices used in temporary traffic control or for incident management. The guidelines presented are in accordance with the standards provided within the Indiana Manual for Uniform Traffic Control Devices (IMUTCD). This handbook is based upon one created by the Ohio Department of Transportation, Guidelines for Traffic Control in Work Zones. Indiana LTAP expresses thanks to ODOT for their permission to reprint this material.

Microspike Based Chemical/Electric Thruster Concept For Versatile Nanosat Propulsion, Anthony Cofer, A Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Small spacecraft that can be categorized as microsats, nanosats, and picosats has a strong potential for wide applications in communication, scientific experiments, and space exploration. In order to combine the advantages of both electric and chemical propulsion thrusters, a dual-mode microspike based thruster concept is proposed. For a fixed input power, it can operate in either a high-Isp mode or a high-thrust mode depending on the propulsive maneuver requirements. The hybrid thruster consists of a plug-annular cold or heated gas thruster in the chemical mode and a field emission thruster housed within the plug operating in the electric mode using …

Analysis Of Peer Intersection Data For Arterial Traffic Signal Coordination Decisions, Christopher M. Day, Thomas M. Brennan Jr, Hiromal Premachandra, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

This is the author-accepted manuscript version of Day, C.M., T.M. Brennan, H. Premachandra, J.R. Sturdevant, and D.M. Bullock, “Analysis of Peer Data on Intersections for Decisions About Coordination of Arterial Traffic Signal,”Transportation Research Record: Journal of the Transportation Research Board, No. 2259, Transportation Research Board of the National Academies, Washington, D.C., pp. 23–36, 2011, copyright National Academy of Sciences.http://dx.doi.org/10.3141/2259-03

Its corresponding poster can be found here:http://docs.lib.purdue.edu/atspmw/2016/Posters/3/

Direct Simulation Monte Carlo Study Of Effects Of Thermal Nonuniformities In Electron-Beam Physical Vapor Deposition, A Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

In a typical electron-beam physical vapor deposition system, there is limited control over how the high-power electron beam heats the metal surface. This leads to thermal nonuniformities at the melt. Three-dimensional direct simulation Monte Carlo simulations were performed with the aim of quantifying the effect of such spatial variations of source temperature in thin film depositions using an electron-beam physical vapor deposition system. The source temperature distribution from a typical deposition process was used in the direct simulation Monte Carlo simulations performed for various mass flow rates. The use of an area-averaged temperature is insufficient for all mass flow rates …

Computational Study Of The Seebeck Coefficient Of One-Dimensional Composite Nanostructures, Raseong Kim, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The Seebeck coefficient (S) of composite nano-structures is theoretically explored within a self-consistent electro-thermal transport simulation framework using the non-equilibrium Green’s function method and a heat diffusion equation. Seebeck coefficients are determined using numerical techniques that mimic experimental measurements. Simulation results show that, without energy relaxing scattering, the overall S of a composite structure is determined by the highest barrier within the device. For a diffusive, composite structure with energy relaxation due to electron-phonon scattering, however, the measured Sis an average of the position-dependent values with the weighting factor being the lattice temperature gradient. The results stress …

Visualizing Non-Equilibrium Flow Simulations Using 3-D Velocity Distribution Functions, A Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Scientific visualization techniques have been used to probe and understand better the physics of non-equilibrium flows. A visualization methodology for nonequilibrium flow simulations using 3-D velocity distribution functions (VDFs) is illustrated in application to various non-equilibrium flow problems. A one-dimensional normal shock wave problem is considered for two different upstream Mach numbers corresponding to weak and strong non-equilibrium flow conditions. The iso-surfaces of 3-D VDFs inside the shock wave obtainedusing various solution techniques including the ES-BGK method, DSMC technique, Mott-Smith solution, and the Navier-Stokes (NS) distribution functions using Chapman-Enskog theory are compared and contrasted. The visualization technique is extended to …

Returning Students In Engineering Education: Making A Case For “Experience Capital”, Michele L. Strutz, James E. Cawthorne Jr, Daniel M. Ferguson, Mark T. Carnes, Matthew Ohland

School of Engineering Education Graduate Student Series

Students returning to college are not generally studied, where most of the research on non-traditional students is focused on individuals returning to earn their undergraduate degree. There are, however, many students returning to receive graduate degrees as they pursue new directions in life by interest or economic necessity. Undergraduate students with experience have clear educational related goals, practical approaches to problem-solving, and high learning motivation.Returning graduate students are expected to model similar behaviors. These individuals bring a lifetime of personal and professional expertise, which we identify as “experience capital.”A review of the literature reveals that capital has been pondered since …

Exploring Curriculum Flexibility And Compliance Through The Use Of A Metric For Curricular Progression, George Dante Ricco, Matthew Ohland

School of Engineering Education Graduate Student Series

No abstract provided.

Integrating Children’S Literature Into Occupational Learning About Engineers, Brianna L. Dorie, Monica Cardella

School of Engineering Education Graduate Student Series

At a very young age, a child has the ability to formulate ideas regarding the occupation of a lawyer, a nurse or even a doctor. However, studies have shown that most children have limited information regarding engineers, and the lack of knowledge can often perpetuate into adulthood(Cunningham et al., 2005; NAE, 2002). Augur et al. (2005) found that “occupational aspirations and expectations of children undergo dramatic development changes during the elementary years, as well as resisting change in other respects.” This means prior to school education,children have already formed their perception of occupations and that stereotypical attributes have already been …

Dsmc Collision Model For The Lennard-Jones Potential: Efficient Algorithm And Verification, A Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

An efficient algorithm to implement elastic scattering using the Lennard-Jones (LJ) intermolecular potential in the direct simulation Monte Carlo (DSMC) method is presented. The exact elastic scattering angle for the LJ intermolecular potential obtained by numerical integration is used to construct a piecewise polynomial representation in terms of two collision parameters - the reduced impact parameter and the reduced relative energy. The 5 thdegree polynomials representation is obtained using the Chebyshev basis. The implementation valid for reduced relative energies ranging from 0.001 to 10.0 is verified by DSMC simulations of subsonic and supersonic Couette flow of Argon at temperatures of …

Effects Of Uncertainty In Gas-Surface Interaction On Dsmc Simulations Of Hypersonic Flows, Marat Kulakhmetov, A Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

This study uses the non-intrusive generalized polynomial chaos method to investigate the effects of uncertainties in the gas-surface interaction model on the hypersonic boundary layer flow over a flat plate. In particular, the polynomial chaos method is applied to assess uncertainties in the surface shea, normal stress, heat flux, flowfield temperature and accomodation coefficient. The polynomial chaos approach allows us to estimate probability density functions from fewer flowfield samples than the traditional random Monte Carlo sampling. The flowfield solutions are computed by the DSMC code SMILE. The analysis shows that surface fluxes and flowfields in the hypersonic boundary layer are …

Full Dispersion Vs. Debye Model Evaluation Of Lattice Thermal Conductivity With A Landauer Approach, Changwook Jeong, Supriyo Datta, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Using a full dispersion description of phonons, the thermal conductivities of bulk Si and Bi2Te3 are evaluated using a Landauer approach and related to the conventional approach based on the Boltzmann transport equation. A procedure to extract a well-defined average phonon mean-free-path from the measured thermal conductivity and given phonon-dispersion is presented. The extracted mean-free-path has strong physical significance and differs greatly from simple estimates. The use of simplified dispersion models for phonons is discussed, and it is shown that two different Debye temperatures must be used to treat the specific heat and thermal conductivity (analogous to the two different …

The Effect Of Static Pressure On The Inertial Cavitation Threshold And Collapse Strength, Kenneth Bryan Bader

Electronic Theses and Dissertations

The amplitude of the acoustic pressure required to nucleate a gas and/or vapor bubble in a fluid, and to have that bubble undergo an inertial collapse, is termed the inertial cavitation threshold. The hydrostatic dependence of the inertial cavitation threshold was measured up to 30 MPa in ultrapure water using a high quality factor spherical resonator. The threshold increased linearly with the hydrostatic pressure and was found to be temperature dependent. The strength of the bubble collapse at the threshold was measured in terms of shock waves and light emissions. The shock amplitudes increased linearly with the hydrostatic pressure, while …

Rate-Dependent Stiffening And Strain Localization In Physically Associating Solutions, Kendra Erk, Kenneth R. Shull

School of Materials Engineering Faculty Publications

Model physically associating solutions of acrylic triblock copolymer molecules in a midblock-selective solvent displayed non-linear strain-stiffening behavior which transitioned to rapid strain softening during shear start-up experiments at reduced rates spanning almost four orders of magnitude. Softening was believed to result from the shear-induced formation of highly localized regions of deformation in the macromolecular network. This behavior was accurately captured by a model that incorporated the strain energy and relaxation behavior of individual network strands in the solution. Flow curves predicted from the model were non-monotonic, consistent with the onset of flow instabilities at high shear rates. The non-linear stress …

Engineering Children's Literature: Development Of An Engineering Storybook For Young Children, Brianna L. Dorie, Monica Cardella

School of Engineering Education Graduate Student Series

While the notions of doctor, teacher and firefighter are ubiquitous in young literature,there is a lack of engagement about engineering (Holbrook et al., 2008). Picture books are a compelling medium for introducing concepts to children at a young age. Story books have the ability to present new information, increase stimulation of the imagination, and deliver messages both moral and social. In a school setting, story books have been shown to impact kindergartener’s mathematical achievement when produced in tandem with a mathematics unit (Keat & Wilburne, 2009). However, there have been little to no studies regarding the impact of engineering literature …

Comparative Analysis Of A Low-Speed Wind Tunnel Designed For Renewable Energy Applications, Craig A. Zehrung

Purdue Polytechnic Masters Theses

This thesis describes the design, testing, and validation of an open-circuit, mid-sized wind tunnel used for the teaching of undergraduate courses and testing of green energy wind turbines. This thesis uses computational fluid dynamics to determine theoretical values for flow of the wind tunnel which were statistically compared to actual values of fluid flow. An overall analysis of efficiency and effectiveness were also performed. However, aerodynamic testing of actual prototype turbines will not be covered in this thesis, as it does not concern the tunnels adherence to theoretical flow values.

Using Smartphones For Indoor Navigation, Benjamin Thomas Loulier

Purdue Polytechnic Masters Theses

This directed projet is about the use of smartphones for indoor navigation.

Nowadays, indoor navigation is a real challenge, we are all familiar with the multiple applications of GPS based navigation but all these applications cannot be transfered in an indoor environment as we cannot receive a GPS signal inside.

The document is composed of three different parts related to indoor navigation using smartphones. The first part presents an inertial positioning system for pedestrians walking in an indoor environment, this system is implemented on an iPhone 4. In the second part we introduce a positioning system using RFID tags scattered …