Engineering Commons^™

Thermal Resistance At An Interface Between A Crystal And Its Melt, Zhi Liang, William J. Evans, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Non-Equilibrium Molecular Dynamics Simulations Are Used to Determine Interfacial Thermal Resistance (Kapitza Resistance) between a Crystal and its Melt for Three Materials Including Ar, H2O, and C8H 18 (Octane). the Simulation Results Show that the Kapitza Resistance at a Crystal-Melt Interface is Very Small and Thus Has a Negligible Effect on Thermal Transport Across the Crystal-Melt Interface. the Underlying Origins of This Behavior Are the Very Good Vibrational Property Match between the Two Materials Forming the Interface and Good Interfacial Bonding. the Result Also Indicates that the Commonly-Used Assumption that Temperature Profile is Continuous at the Crystal-Melt Interface is Valid …

31p Dynamic Nuclear Polarization Applied To Dimethyl Methyl Phphonate For Functional Imaging And Spectroscopic Studies, Roha Afzal

USF Tampa Graduate Theses and Dissertations

In the recent years, Dynamic Nuclear Polarization (DNP) has emerged as a very promising technique for enhancing the sensitivity of the magnetic resonance spectroscopy and imaging (MRSI). A number of nuclei, namely 13C, 15N, 29Si, 89Y, and 129Xe, have been successfully polarized and a few of them have been employed in the in-vivo studies for functional imaging and metabolism. Hyperpolarized 13C-labeled compounds have wide applications in the metabolic and perfusion studies and can be used for early stage disease diagnosis, response to treatment, prognosis etc. DNP has been demonstrated in the 31P nucleus in nucleotides triphosphates as an application for …

Feasibility Of Application Of Cathodic Prevention To Cracked Reinforced Concrete In Marine Service, Kevin Williams

USF Tampa Graduate Theses and Dissertations

Corrosion can take place as chloride ions accumulate above a critical concentration (CT) at the surface of a reinforcing bar inside concrete in marine service. The initiation of corrosion can be delayed by polarizing the steel cathodically, which is known to increase the value of CT. That effect is the basis of the cathodic prevention (CPrev) method to control corrosion of reinforcing steel in concrete. However, concrete cracks are a common occurrence and at cracks, the buildup of chloride ions is accelerated to the extent that CPrev may be less effective. The findings from an ongoing investigation to determine the …

Organic-Based Microwave Frequency Absorbers Using Corn Stover, Ben Smythe, Sean Casserly, Dean Arakaki

Electrical Engineering

Commercial antenna test chambers (anechoic) currently use polyurethane foam absorbers on chamber interiors to eliminate undesired radio-frequency (RF) reflections. While effectively absorbing microwave signals, polyurethane material particulates over time adding contaminants to clean rooms and reducing absorber lifetime. These absorbers also release toxic gas when operating under high temperatures and pose a health risk to direct-contact personnel. This paper presents reflectivity analysis and performance of alternative organic-based (corn stover) microwave frequency absorbers for use in anechoic chambers. These absorbers are composed of renewable materials and eliminate the toxic gas release problem for polyurethane materials under high power test conditions. Preliminary …

Multi-Technique Broadband Microstrip Patch Antenna Design, Daniel Colles, Dean Arakaki

Electrical Engineering

Microstrip patch antennas offer low profile and small footprint advantages, but limited operating bandwidth. Substantial research focuses on broadband techniques. This paper presents the design, simulation, fabrication, and characterization of a 30% bandwidth microstrip patch antenna that incorporates multiple broadband techniques while minimizing footprint area. Methods include patch shape, dielectric thickness, and coupling slot optimization, with capacitively-coupled L-probe feeds. The final design incorporates an electrically thick dielectric and circular-E patch geometry. Microstrip L-probe feed and coupling slot dimensions were optimized via HFSS simulations. The final design was fabricated, and then tested in an anechoic chamber. The new design has measured …

Localized Expansion Of Pedicle Screws For Increased Stability And Safety In The Osteoporotic Spine, Thomas Michael Shea

USF Tampa Graduate Theses and Dissertations

When a patient is diagnosed with various spinal injuries, deformities, or advanced degeneration, it is commonly suggested that he/she undergoes surgery for spinal fusion. Most current procedures in spinal fusion restrict mobility in one or multiple levels of the spine so that, over time, new bone will grow between the levels creating a single motionless unit of bone. The bilateral pedicle screw system (BPSS) has long been considered to be the "gold standard" in spinal fusion. However, for patients with osteoporosis, adequate fixation within the bone-screw interface has continuously been difficult to achieve or has come with high risk of …

Dual-Channel Red/Blue Fluorescence Dosimetry With Broadband Reflectance Spectroscopic Correction Measures Protoporphyrin Ix Production During Photodynamic Therapy Of Actinic Keratosis, Stephen Chad Kanick, Scott C. Davis, Yan Zhao, Tayyaba Hasan, Edward V. Maytin, Brian W. Pogue, M Shane Chapman

Dartmouth Scholarship

Dosimetry for aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) photodynamic therapy of actinic keratosis was examined with an optimized fluorescence dosimeter to measure PpIX during treatment. While insufficient PpIX generation may be an indicator of incomplete response, there exists no standardized method to quantitate PpIX production at depths in the skin during clinical treatments. In this study, a spectrometer-based point probe dosimeter system was used to sample PpIX fluorescence from superficial (blue wavelength excitation) and deeper (red wavelength excitation) tissue layers. Broadband white light spectroscopy (WLS) was used to monitor aspects of vascular physiology and inform a correction of fluorescence for …

Oswald Physical And Engineering Sciences First Place: An Improved In Vitro Model For The Study Of Endothelial Cells Using Micropatterned Surfaces, Lindsay Gray

Kaleidoscope

Sickle cell anemia, malaria, and cancer are a few of the deadly diseases that utilize blood vessels as a means of migration throughout the body. Adhesion of harmful cells to the endothelial lining of the circulatory system is an integral step in the metastasis of blood borne diseases. As a result of shear stress produced by blood flow through veins and arteries, the endothelium undergoes a distinct morphological change resulting in a more elongated and unidirectional morphology. It has recently been suggested that such changes in cell morphology can affect surface expression profiles, which in turn affects cell-cell binding and …

Oswald Physical And Engineering Sciences Second Place: Multiple Macromer Hydrogels For Multiphase Drug Release, David Spencer

Kaleidoscope

Biodegradable hydrogels are of interest for drug delivery applications due to their resemblance to biological tissue and their ability to absorb large amounts of biological fluids. Here, hydrogels were synthesized from multiple macromers to demonstrate step-wise degradation and multiphase drug release profiles. Control over the degradation and release profiles of multiple macromer hydrogels has potential applications in implantable, extended release drug delivery devices in which removal would not be needed after administration. Herein, macromers were synthesized from diethylene glycol diacrylate (A), poly(ethylene glycol) diacrylate (n=400) (H), and isobutylamine (6) in 1.2:1 molar ratios of total diacrylate to amine with diacrylate …

Oswald Physical And Engineering Sciences Honorable Mention: Summer 2012 Lip6 Write Up, Josiah Hanna

Kaleidoscope

Planning under uncertainty is a central problem in developing intelligent autonomous systems. The traditional representation for these problems is a Markov Decision Process (MDP). The MDP model can be extended to a Multi-criteria MDP (MMDP) for planning under uncertainty while trying to optimize multiple criteria. However, due to the trade-offs involved in multi criteria problems there may be infinitely many optimal solutions. The focus of this project has been to find a method that efficiently computes a subset of solutions that represents the entire set of optimal solutions for bi-objective MDPs.

Human Brain Networks: Spiking Neuron Models, Multistability, Synchronization, Thermodynamics, Maximum Entropy Production, And Anesthetic Cascade Mechanisms, Wassim H. Haddad, Qing Hui, James M. Bailey

Department of Electrical and Computer Engineering: Faculty Publications

Advances in neuroscience have been closely linked to mathematical modeling beginning with the integrate-and-fire model of Lapicque and proceeding through the modeling of the action potential by Hodgkin and Huxley to the current era. The fundamental building block of the central nervous system, the neuron, may be thought of as a dynamic element that is “excitable”, and can generate a pulse or spike whenever the electrochemical potential across the cell membrane of the neuron exceeds a threshold. A key application of nonlinear dynamical systems theory to the neurosciences is to study phenomena of the central nervous system that exhibit nearly …

Simulation Of Light Propagation In Skin And Subcutaneous Blood Vessels, Robert Polski, Ricardo Huancaya, Hyun J. Kwon

Posters, Presentations, and Papers

The VeinViewer, produced by the Luminetx Corporation, projects an image of subcutaneous veins onto the surface of the skin by using the discovery that near infrared (NIR) light passes through and transmits back out of the skin issue except at the blood vessels as a result of the presence of hemoglobin¹. We aim to improve the function of the VeinViewer by using computational models to interpret changes in properties of the subject,such as skin pigmentation, and settings on the device, such as light frequency. We also look to decrease error, as a result of the geometry of veins …

Comparison Of Different Approaches To Estimating Budgets For Kuhn-Tucker Demand Systems: Applications For Individuals' Time-Use Analysis And Households' Vehicle Ownership And Utilization Analysis, Bertho Augustin

USF Tampa Graduate Theses and Dissertations

This thesis compares different approaches to estimating budgets for Kuhn-Tucker (KT) demand systems, more specifically for the multiple discrete-continuous extreme value (MDCEV) model. The approaches tested include: (1) The log-linear regression approach (2) The stochastic frontier regression approach, and (3) arbitrarily assumed budgets that are not necessarily modeled as a function of decision maker characteristics and choice-environment characteristics.

The log-linear regression approach has been used in the literature to model the observed total expenditure as way of estimating budgets for the MDCEV models. This approach allows the total expenditure to depend on the characteristics of the choice-maker and the choice …

Analysis And Application Of Passive Gait Rehabilitation Methods, Ismet Handzic

USF Tampa Graduate Theses and Dissertations

Human gait is elegant and efficient in propelling the body forward. While a healthy human gait is symmetric, any deviation from symmetry can cause inefficiencies to the entire body. Such asymmetries may present themselves in hemiplegic patients, prosthetic users, lower limb injuries, limb height and weight discrepancies, or abnormal overground foot rolling. In this dissertation, practical passive methods to alleviate such asymmetric walking dynamics are presented. The novel concepts presented in this manuscript can all be related and applied to passive gait rehabilitation, that is, the rehabilitation of a person's gait through methods that do not require external power. One …

Photonic-Band-Gap Engineering For Volume Plasmon Polaritons In Multiscale Multilayer Hyperbolic Metamaterials, Sergei V. Zhukovsky, Alexey A. Orlov, Viktoriia E. Babicheva, Andrei V. Lavrinenko, J. E. Sipe

Birck and NCN Publications

We study theoretically the propagation of large-wave-vector waves (volume plasmon polaritons) in multilayer hyperbolic metamaterials with two levels of structuring. We show that when the parameters of a subwavelength metal-dielectric multilayer (substructure) are modulated (superstructured) on a larger, wavelength scale, the propagation of volume plasmon polaritons in the resulting multiscale hyperbolic metamaterials is subject to photonic-band-gap phenomena. A great degree of control over such plasmons can be exerted by varying the superstructure geometry. When this geometry is periodic, stop bands due to Bragg reflection form within the volume plasmonic band. When a cavity layer is introduced in an otherwise periodic …

Modified Active Disturbance Rejection Control For Time-Delay Systems, Shen Zhao, Zhiqiang Gao

Electrical and Computer Engineering Faculty Publications

Industrial processes are typically nonlinear, time-varying and uncertain, to which active disturbance rejection control (ADRC) has been shown to be an effective solution. The control design becomes even more challenging in the presence of time delay. In this paper, a novel modification of ADRC is proposed so that good disturbance rejection is achieved while maintaining system stability. The proposed design is shown to be more effective than the standard ADRC design for time-delay systems and is also a unified solution for stable, critical stable and unstable systems with time delay. Simulation and test results show the effectiveness and practicality of …

Deriving Statewide Freight Truck Flows From Global Positioning System (Gps) Data, Akbar Bakhshi Zanjani

USF Tampa Graduate Theses and Dissertations

An accelerated growth in the volume of freight shipped on Florida's highways has led to a significant increase in truck traffic, influencing traffic operations, safety, and the state of repair of highway infrastructure. Traffic congestion in turn has impeded the speed and reliability of freight movement on the highway system. Appropriate planning and decision making processes are necessary to address these issues. However, a main challenge in establishing such processes is the lack of adequate data on statewide freight movements. As traditional data sources on freight movement are either inadequate or no longer available, new sources of data must be …

Evaluation And Modeling Of Internal Water Storage Zone Performance In Denitrifying Bioretention Systems, Thomas Joseph Lynn

USF Tampa Graduate Theses and Dissertations

Nitrate (NO3) loadings from stormwater runoff promote eutrophication in surface waters. Low Impact Development (LID) is a type of best management practice aimed at restoring the hydrologic function of watersheds and removing contaminants before they are discharged into ground and surface waters. Also known as rain gardens, a bioretention system is a LID technology that is capable of increasing infliltration, reducing runoff rates and removing pollutants. They can be planted with visually appealing vegetation, which plays a role in nutrient uptake. A modified bioretention system incorporates a submerged internal water storage zone (IWSZ) that includes an electron donor to support …

Recursive-Ransac: A Novel Algorithm For Tracking Multiple Targets In Clutter, Peter C. Niedfeldt

Theses and Dissertations

Multiple target tracking (MTT) is the process of identifying the number of targets present in a surveillance region and the state estimates, or track, of each target. MTT remains a challenging problem due to the NP-hard data association step, where unlabeled measurements are identified as either a measurement of an existing target, a new target, or a spurious measurement called clutter. Existing techniques suffer from at least one of the following drawbacks: divergence in clutter, underlying assumptions on the number of targets, high computational complexity, time-consuming implementation, poor performance at low detection rates, and/or poor track continuity. Our goal is …

Getting It Right The First Time: Verification Of Behavior-Based Multirobot Missions, Damian M. Lyons, Ronald C. Arkin, Shu Jiang, Dagon Harrington, Matthew O'Brien

Faculty Publications

No abstract provided.

Leveraging Area Bounds Information For Autonomous Multi-Robot Exploration, Tsung-Ming Liu, Damian M. Lyons

Faculty Publications

In this paper we propose an approach, the Space-Based Potential Field (SBPF) approach, to controlling multiple robots for area exploration missions that focus on robot dispersion. The SBPF method is based on a potential field approach that leverages knowledge of the overall bounds of the area to be explored. This additional information allows a simpler potential field control strategy for all robots but which nonetheless has good dispersion and overlap performance in all the multi-robot scenarios while avoiding potential minima. Both simulation and robot experimental results are presented as evidence.

Juvenile Green Sturgeon (Acipenser Medirostris) And White Sturgeon (Acipenser Transmontanus) Behavior Near Water-Diversion Fish Screens: Experiments In A Laboratory Swimming Fume, Jamilynn B. Poletto, Dennis E. Cocherell, Natalie Ho, Joseph J. Cech Jr., A. Peter Klimley, Nann A. Fangue

School of Natural Resources: Faculty Publications

Water diversions that extract fresh water for urban, industrial, and agricultural uses, as well as export to southern California, are prevalent throughout the Sacramento–San Joaquin watershed. Many water diversions are fitted with fish-exclusion screens designed to prevent fish from entrainment (i.e., being drawn in). The impact of fish screens on the behavior of migrating juvenile fishes remains largely unknown, especially for threatened species such as sturgeon. We placed individual juvenile green (Acipenser medirostris) or white (Acipenser transmontanus) sturgeon in a laboratory swimming flume in the presence of standard fish screens (2 mm bar spacing) at two …

Implementation Of Stature Risk Management Tool In Company Xyz, Abc Business, Peter Halter

Culminating Projects in Electrical Engineering

The ABC business unit within our corporation has no single, easy to use, risk management software platform. This has caused discrepancies between and within risk assessments and delays in regulatory approvals due to changes being requested by the notified bodies. It also led to numerous document formats existing in our Product Data Management system for the same types of documents. This costs the company time and money and was a burden on those responsible for creating and managing these assessments. The objective of this project was to implement a single risk management tool within the ABC business that would mitigate …

Acoustic Testing Of Generator/Alternator Fans, Jacob Kriesel

Culminating Projects in Electrical Engineering

The intent of this project was to fill in a gap of the testing knowledge possessed for acoustics of an alternator within a generator set. The objective was to build a test fixture that would allow the user to test the acoustics of alternators without the driving force of an engine, which is a high acoustic source during testing. Eliminating the engine from the equation would allow for more accurate data of the product line, allowing for better utilization of acoustic tools when implementing sound source dampening. At the end of the project, it was found that the test fixture …

An Enhanced Archive Facilitating Climate Impacts And Adaptation Analysis, Edwin P. Maurer, Levi Brekke, Tom Pruitt, Bridget Thrasher, J. Long, Philip B. Duffy, Michael D. Dettinger, Daniel R. Cayan, James W. Arnold

Civil, Environmental and Sustainable Engineering

We describe the expansion of a publicly available archive of downscaled climate and hydrology projections for the United States. Those studying or planning to adapt to future climate impacts demand downscaled climate model output for local or regional use. The archive we describe attempts to fulfill this need by providing data in several formats, selectable to meet user needs. Our archive has served as a resource for climate impacts modelers, water managers, educators, and others. Over 1,400 individuals have transferred more than 50 TB of data from the archive. In response to user demands, the archive has expanded from monthly …

Acuta Enews July 2014 Vol. 43, No. 7

ACUTA Newsletters

In this Issue,,.

I Secrets of Effective PD: The 3 P's

2 Webinar: Cooking in the Cloud i Canada's Anti-spam Law (CASL)

3 Annual Dues Reminders Mailed

4 Register for Fall Seminar in Boston

5 911? 9911?

6 My First Encounter with the Budgeting Process

7 lnfo Links

8 Board Report

9 Check It Out

Nonlocal And Quantum-Tunneling Contributions To Harmonic Generation In Nanostructures: Electron-Cloud-Screening Effects, Michael Scalora, Maria Antonietta Vincenti, Domenico De Ceglia, Joseph W. Haus

Electrical and Computer Engineering Faculty Publications

Our theoretical examination of second- and third-harmonic generation from metal-based nanostructures predicts that nonlocal and quantum-tunneling phenomena can significantly exceed expectations based solely on local, classical electromagnetism. Mindful that the diameter of typical transition-metal atoms is approximately 3 Å, we adopt a theoretical model that treats nanometer-size features and/or subnanometer-size gaps or spacers by taking into account (i) the limits imposed by atomic size to fulfill the requirements of continuum electrodynamics, (ii) spillage of the nearly free electron cloud into the surrounding vacuum, and (iii) the increased probability of quantum tunneling as objects are placed in close proximity.

Our approach …

Study Of A Generalized Empirical Model For Predicting Pressure Drop For Internal Flows, Tejas Anup Pant

Open Access Theses

A generalized empirical model for estimating the pressure drop across a channel for a given massflow rate is studied through computational fluid dynamics (CFD) simulations. It is observed that for developing laminar and turbulent flow through channels and pipes of arbitrary cross-section, the variation in the pressure drop between any two points in the flow direction with massflow rate can be well approximated by a second degree expression in massflow rate which is referred to as the empirical model in this study. In the first part of this study, a correlation between the pressure gradient and the massflow rate is …

Sustainable Development Of Biogas Resources In East Africa Using Transdisciplinary Design Models, Christopher M. Limiac

Open Access Theses

Installation of anaerobic digestion systems in urban developing communities has the potential to address multiple problems related to energy and sanitation in a combined systems approach. Anaerobic digesters are used to generate a relatively clean and rich source of energy in the form of biogas to address energy poverty issues. The design resources available for anaerobic digestion projects must be improved to provide greater technical support and project transparency. In order to develop holistic solutions to grand challenges like energy poverty, engineers must be prepared to operate with the complexities of diverse environments. Globalization and the improvement of transdisciplinary project …

Getting It Right The First Time: Verification Of Autonomous Behavior-Based Multirobot Missions, Ronald C. Arkin, Damian M. Lyons

Faculty Publications

No abstract provided.