Engineering Commons^™

Static And Dynamic Components Of Droplet Friction, Peter Robert Griffiths

USF Tampa Graduate Theses and Dissertations

As digital microfluidics has continued to mature since its advent in the early 1980's, an increase in new and novel applications of this technology have been developed. However, even as this technology has become more common place, a consensus on the physics and force models of the motion of the contact line between the fluid, substrate, and ambient has not been reached. This uncertainty along with the dependence of the droplet geometry on the force to cause its motion has directed much of the research at specific geometries and droplet actuation methods.

The goal of this thesis is to help …

Corrosion Of Post-Tensioning Strands In Ungrouted Ducts - Unstressed Condition, Michael John Hutchison

USF Tampa Graduate Theses and Dissertations

Recent failures and severe corrosion distress of post-tensioned (PT) bridges in Florida have revealed corrosion of the 7-wire strands in tendons. Post-tensioned duct assemblies are fitted with multiple 7-wire steel strands and ducts are subsequently filled with grout. During construction, the length of time from the moment in which the strands have been inserted into the ducts, until the ducts are grouted, is referred to as the `ungrouted' period. During this phase, the steel strands are vulnerable to corrosion and consequently the length of this period is restricted (typically to 7 days) by construction guidelines. This investigation focuses on determining …

Human Intention Recognition Based Assisted Telerobotic Grasping Of Objects In An Unstructured Environment, Karan Hariharan Khokar

USF Tampa Graduate Theses and Dissertations

In this dissertation work, a methodology is proposed to enable a robot to identify an object to be grasped and its intended grasp configuration while a human is teleoperating a robot towards the desired object. Based on the detected object and grasp configuration, the human is assisted in the teleoperation task. The environment is unstructured and consists of a number of objects, each with various possible grasp configurations. The identification of the object and the grasp configuration is carried out in real time, by recognizing the intention of the human motion. Simultaneously, the human user is assisted to preshape over …

Experimental Study Of Optimal Energy Weighting In Energy-Resolved Ct Using A Czt Detector, Franco Rupcich, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Recent advances in energy-resolved CT can potentially improve contrast-to-noise ratio (CNR), which could subsequently reduce dose in conventional and dedicated breast CT. Two methods have been proposed for optimal energy weighting: weighting the energy-bin data prior to log normalization (projection-based weighting) and weighting the energy-bin data after log normalization (image-based weighting). Previous studies suggested that optimal projection-based and image-based energy weighting provide similar CNR improvements for energy-resolved CT compared to photon-counting or conventional energy-integrating CT. This study experimentally investigated the improvement in CNR of projection-based and image-based weighted images relative to photon-counting for six different energy-bin combinations using a bench …

Proximity Heating Effects In Power Cables, Jonathan Blackledge, Eugene Coyle, Kevin O'Connell

Articles

Researchers at Technological University Dublin (DIT) have developed a new modelling system for evaluating the two and three dimensional heating effects in power cables due to harmonic distortion and proximity field effects.

Three Dimensional Simulation Of The Radiation Field Patterns Generated By An Integrated Antenna, Jonathan Blackledge, Bazar Babajanov

Articles

Simulating the electromagnetic field patterns generated by integrated antennas uses in mobile phones, for example, is fundamental to understanding their transmission characteristics and thereby engineering designs that optimize the directional properties of electromagnetic propagation. Modern integrated antennas have complex three-dimensional geometry designed to optimize their performance in terms of their multi-band and multi -modal attributes. This geometry, coupled with their close proximity to other component of the device (such as the battery and Printed Circuit Board, for example) produce complex field patterns due to the scattering of the electric (and magnetic) field within a spatial domain that is the same …

Evaluation Of Proximity Heating Effects In Power Cables, Jonathan Blackledge, Eugene Coyle, Kevin O'Connell

Articles

No abstract provided.

Inverter Performance For Small Wind Turbines When Connected In Paralled With The Low-Voltage Distribution System, Jonathan Blackledge, Eugene Coyle, Derek Kearney, Eamonn Murphy

Articles

Small wind turbines have been installed in urban and turbulent locations with surprisingly poor performance and this has been backed up by data from a trial at the Technological University Dublin. In order to develop the small wind turbine industry a careful examination of assessment methods for the wind resource is required. Small wind turbines connected in parallel with the grid use inverters. As the wind turbine is not always at max output, a Weighted Average Efficiency for wind inverters is proposed. Pitfalls associated with developing an accurate weighted average efficiency for an inverter are identified and this will enable …

The Fractional Schrodinger-Klein-Gordon Equation And Intermediate Relativism, Jonathan Blackledge, Bazar Babajanov

Articles

By considering a random walk model compounded in Einstein's evolution equation, we show that both the classical Schrodinger and Klein-Gordon equations can be viewed a s consequence of introducing a memory function.

The purpose of this is to derive a wave equaiton that, on a phenomenological basis at least, describes the transitional characteristics of wave functions for spin-less particles that may exist in the intermediate of "semi relativistic regime.

A Review Of Existing Microgrid Architectures, Lubna Mariam, Malabika Basu, Michael Conlon

Articles

The future electricity network must be flexible, accessible, reliable, and economic according to the worldwide smartgrid initiative. This is also echoed by the Sustainable Energy Authority of Ireland (SEAI) and European Electricity Grid Initiative (EEGI). In order to facilitate these objectives and to reduce green house gas (GHG) emission, research on various configurations of microgrid system is gaining importance, particularly with high penetration of renewable energy sources. Depending on the resource availability, geographical locations, load demand, and existing electrical transmission and distribution system, uG can be either connected to 6the grid or can work in an autonomous mode. Storage can …

On The Dirac Scattering Problem, Jonathan Blackledge, Bazar Babajanov

Articles

We consider a method of solving the Dirac scattering problem based on an approach previously used by the authors to solve the Schrodinger scattering problem to develop a conditional exact scattering solution and an unconditional series solution. We transform the Dirac scattering problem into a form that facilitates a soltuion based on the relativistic Lippmann-Schwinger equation using the relativistic Green's function that is transcendental in terms of the scattered field. Using the Dirac operator, this solution is transformed further to yield a modified relativistic Lippman-Schwinger equation that is also transcendental in terms of the scattered field. This modified solution faclitates …

Selection Of Design Parameters To Reduce The Zero-Sequence Circulating Current Flow In Parallel Operation Of Dc Linked Multiple Shunt Apf Units, Shafiuzzaman Khadem, Malabika Basu, Michael Conlon

Articles

Capacity enhancement and operational flexibility are two of the important limitations of the centralized shunt APF unit. These limitations can be conquered by the operation of multiple APF units in parallel and connected back to back by a common DC link capacitor. In that case, a circulating current (CC) flows within the APF units. This CC flow becomes out of control when the APF units operate in hysteresis based current controlled mode. One of the difficulties of this CC flow control or reduction is the variable switching frequency of the APF units. In this paper the model for CC flow …

Disinfection Performance Of Peracetic Acid In Florida Wastewater Reuse Applications, Killian Eckert

UNF Graduate Theses and Dissertations

As Florida’s population continues to grow and urbanization increases, traditional freshwater sources are in danger of being exhausted. Wastewater reuse programs offer a way to create a potable offset in order to protect these freshwater sources and the environments in which they are found. Reuse regulations for the disinfection of wastewater are increasingly becoming more stringent. In addition to tough regulations, operating costs have also become a driving force behind a movement to assess new and potentially economical chemicals and processes for disinfection. The objective of this thesis is to assess the disinfection performance of peracetic acid (PAA), an alternative …

Recession And Renting: The Future Of The Private Rented Sector In Ireland, Lorcan Sirr

Conference papers

No abstract provided.

Project Haiti 2012: Providing An Experiential Learning Experience Through The Design And Delivery Of A Water Purifier In Haiti, Yung Wong, Johnathon Camp, Shavin Pinto, Kyle Fennesy, Marc Compere, Yan Tang

Publications

In this paper, we share our experiences and lessons learned from Project Haiti 2012, a project to design and install a water purification system serving 20,000 people per day in the largest tent city in Haiti. Project Haiti 2012 was the third and largest system we have built for Haitians and represents a huge success for all participants and stakeholders. This paper discusses the unique experiential learning opportunity involved in the design and delivery of the water purifier in a foreign developing country. Multiple positive educational, social, and economic outcomes were achieved including students applying knowledge gained from coursework towards …

Examining Student Success: The Transition From H.S. To College Of First-Year Engineering Students, Leroy L. Long Iii

Publications

To improve retention and graduation rates, institutions of higher education have become increasingly interested in the experiences of first-year students. This is of even greater importance in STEM (science, technology, engineering and mathematics) fields such as engineering which are crucial for U.S. global competitiveness and homeland security. Interviews were conducted with six (6) first-year engineering students at a large, predominantly White land-grant institution located in the Midwestern region of the country to study their decisions and experiences during the transition from high school to college. More specifically, the investigation focused on under-represented students within undergraduate engineering. Interviews focused on three …

First-Year Engineering Program: Student Instructional Leadership Team - Expanded And Restructured, Leroy L. Long Iii, Alison Snyder, Russell Stech, Ben Jelen, Cody Allison, John Merrill

Publications

Since its initial creation, the Student Instructional Leadership Team (SILT) within the First-Year Engineering Program (FEP) at The Ohio State University (OSU) has been responsible for training and supporting students and instructional staff. In recent years, SILT has been expanded and restructured to meet the needs of a growing student body and ever-changing program. SILT currently has 13 members working across all 4 tracks of FEP. This team helps manage over 2,000 students and 200 teaching assistants (TAs). SILT assists with various FEP resources such as its computer lab and laboratories. SILT also provides professional development opportunities for student employees. …

Walking, Running, And Resting Under Time, Distance And Average Speed Constraints: Optimality Of Walk-Run-Rest Mixtures, Leroy L. Long Iii, Manoj Srinivasan

Publications

On a treadmill, humans switch from walking to running beyond a characteristic transition speed. Here, we study human choice between walking and running in a more ecological (non-treadmill) setting. We asked subjects to travel a given distance overground in a given allowed time duration. During this task, the subjects carried, and could look at, a stop-watch that counted down to zero. As expected, if the total time available were large, humans walk the whole distance. If the time available were small, humans mostly run. For an intermediate total time, humans often use a mixture of walking at a slow speed …

Academic And Social Barriers To Black And Latino Male Collegians' Success In Engineering And Related Stem Fields, Terrell Lamont Strayhorn, Leroy L. Long Iii, Joseph Allen Kitchen, Michael Steven Williams, Meg E. Stenz

Publications

Historically underrepresented racial/ethnic minorities (i.e. African Americans, Latinos, and Native Americans) have experienced barriers to their success in engineering and related STEM fields. These student populations have had lower degree attainment rates, switch to non-STEM majors more frequently, and experience unique social challenges when compared to White and Asian Pacific Islander counterparts. To examine these findings, nearly 50 interviews were conducted and analyzed in the present study to better understand the academic and social experiences of African American and Latino American men in these fields. Interviews revealed that these students tend to (1) feel alone and invisible, (2) lack same …

How Relationships With Faculty And Peers Affect Value Development In Undergraduate Engineering Education: A National Survey Analysis, Leroy L. Long Iii, Michael Steven Williams, Terrell Lamont Strayhorn

Publications

To prepare students for the serious ethical dilemmas encountered in STEM (science, technology, engineering, and mathematics), higher education educators strive to influence students’ value development. Despite this goal, little is known about value development in undergraduate engineering education. Survey data from the 2008-2009 national administration of the revised College Student Experiences in STEM Questionnaire (CSESQ) was analyzed to examine the relationship between students’ engagement with faculty and peers and their perceived value development. Findings from the present study offer insight into (a) engineering students’ value development in college, and (b) the influence of relationships with peers and faculty members on …

White Matter Structural Connectivity Is Associated With Sensorimotor Function In Stroke Survivors, Benjamin Kalinosky, Sheila M. Schindler-Ivens, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Purpose

Diffusion tensor imaging (DTI) provides functionally relevant information about white matter structure. Local anatomical connectivity information combined with fractional anisotropy (FA) and mean diffusivity (MD) may predict functional outcomes in stroke survivors. Imaging methods for predicting functional outcomes in stroke survivors are not well established. This work uses DTI to objectively assess the effects of a stroke lesion on white matter structure and sensorimotor function.

Methods

A voxel-based approach is introduced to assess a stroke lesion's global impact on motor function. Anatomical T1-weighted and diffusion tensor images of the brain were acquired for nineteen subjects (10 post-stroke and 9 …

Heteroclinic And Homoclinic Connections Between The Sun-Earth Triangular Points And Quasi-Satellite Orbits For Solar Observations, Pedro J. Llanos, Gerald R. Hintz, Martin W. Lo, James K. Miller

Publications

Investigation of new orbit geometries exhibits a very attractive behavior for a spacecraft to monitor space weather coming from the Sun. Several orbit transfer mechanisms are analyzed as potential alternatives to monitor solar activity such as a sub-solar orbit or quasi-satellite orbit and short and long heteroclinic and homoclinic connections between the triangular points L4 and L5 and the collinear point L3 of the CRTBP (circular restricted three-body problem) in the Sun-Earth system. These trajectories could serve as channels through where material can be transported from L5 to L3 by performing small maneuvers at the departure of the Trojan orbit. …

In Vivo Dark-Field Imaging Of The Retinal Pigment Epithelium Cell Mosaic, Drew Scoles, Yusufu N. Sulai, Alfredo Dubra

Biomedical Engineering Faculty Research and Publications

Non-invasive reflectance imaging of the human RPE cell mosaic is demonstrated using a modified confocal adaptive optics scanning light ophthalmoscope (AOSLO). The confocal circular aperture in front of the imaging detector was replaced with a combination of a circular aperture 4 to 16 Airy disks in diameter and an opaque filament, 1 or 3 Airy disks thick. This arrangement reveals the RPE cell mosaic by dramatically attenuating the light backscattered by the photoreceptors. The RPE cell mosaic was visualized in all 7 recruited subjects at multiple retinal locations with varying degrees of contrast and cross-talk from the photoreceptors. Various experimental …

Biomechanical Modeling Of Pediatric Clubfoot, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Exploring Current And Projected Skills And Knowledge Areas To Meet U.S. Commercial Space Industry Needs, Sonya A. H. Mcmullen, Mac J. Mcmullen, Kenneth Witcher

Publications

In 2007, the Committee on Meeting the Workforce Needs for the National Vision for Space Exploration published findings related to age and skills of the current National Aeronautics and Space Administration (NASA) workforce and projected potential expertise shortages as a result of retirement in the 2014-2015 time frame. In addition, the expanding commercial space industry in both the United States and Europe will likely create further demand for space experts in engineering and a variety of related fields. Although NASA contributes $162 million in funding for education programs annually, those programs target kindergarten through grade 12, not collegiate-level programs. Further, …

Mechanical Characterization Of Composite Repairs For Fiber-Glass Wind Turbine Blades, Tanveer Singh Chawla

Theses and Dissertations

While in service, wind turbine blades experience various modes of loading. An example is impact loading in the form of hail or bird strikes, which might lead to localized damage or formation of cracks a few plies deep on the blade surface. One of the methods to conduct repairs on wind turbine blades that are damaged while in service is hand lay-up of the repair part after grinding out the damaged portion and some of its surrounding area. The resin used for such repairs usually differs from the parent plate resin in composition and properties such as gel time, viscosity, …

Brittle Bone Fracture Risk With Transverse Isotropy, Jessica M. Fritz, Nicole M. Grosland, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Safety And Efficacy Of Ranolazine For The Treatment Of Chronic Angina Pectoris, Mohammed Aldakkak, David F. Stowe, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Coronary heart disease is a global malady and it is the leading cause of death in the United States. Chronic stable angina is the most common manifestation of coronary heart disease and it results from the imbalance between myocardial oxygen supply and demand due to reduction in coronary blood flow. Therefore, in addition to lifestyle changes, commonly used pharmaceutical treatments for angina (nitrates, ß-blockers, Ca2+ channel blockers) are aimed at increasing blood flow or decreasing O2 demand. However, patients may continue to experience symptoms of angina. Ranolazine is a relatively new drug with anti-anginal and anti-arrhythmic effects. Its anti-anginal mechanism …

Biplane Fluoroscopic Analysis Of The Hindfoot Using Model-Based Tracking Techniques: A Static Phantom Study, Janelle A. Cross, Ben Mchenry, Gerald F. Harris, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

No abstract provided.

The Effect Overall Density Plays On Performance And Preference In A Windowed Environment, Lucas M. Downard

UNF Graduate Theses and Dissertations

This thesis consists of fundamental research into the effect that a display’s overall density has on a user’s performance and preference while performing simple tasks using a window-styled computer application specifically developed for this study. This study sought to reevaluate previous findings by exploring their application in the more current, present-day environment. In this research, overall density was considered to be a measure of a screen’s complexity and was examined at three different levels. Users performed a series of tasks using only one of three available screens with different density levels. The same tasks were performed by all users to …