Digital Commons Network^™

Modeling Aperture Radiation For Rf Interference Applications, Liehui Ren

Doctoral Dissertations

"The first topic proposes a rigorous method of moments(MoM) solution to evaluate the shielding effectiveness of a metallic enclosure with apertures on top wall by formulating a pair of coupled mixed potential integral equations (MPIEs). Application of Ewald transform to the computation of Green's function in the cavity yields fast convergence of series summation. Good agreements with a commercial tool, EMC studio, have proved the effectiveness of the proposed approach.

The second topic deals with prediction of electromagnetic interference radiation from components or interconnects in a printed circuit board by using convolution of the half-space Green's functions and the equivalent …

Advanced Neural Networks And Their Applications In Smart Grids, Bipul Luitel

Doctoral Dissertations

"Today, neural networks (NN) are used in several system identification and nonlinear control system applications. However, their implementation on large systems has been limited either because of their degraded performance or the amount of time and computation required for implementing them being impractical for real applications. The primary emphasis of this research is on the development of advanced NN - simultaneous recurrent neural networks (SRN) and cellular neural networks (CNN); and methods for learning the complexity of large systems.

US electricity infrastructure is one of the largest and the most critical infrastructure consisting of thousands of generators connected by transmission …

Analyzing Risk And Catastrophic Accidents: Using Lopa And Human Factors To Improve Safety In Generic Projects, Siddharth B. Damle

Doctoral Dissertations

"Risk assessment and identification in the early stages of any project is critical to the success of that project from time, budget and cost prespective [sic]. Identifying unacceptable risks and making provisions to mitigate those, can reduce the uncertainty in the project and ensure its smooth completion and closure. Various techniques have been developed over time to identify and quantify risks. Inspite of all the available research on risk management tools, accidents continue to happen and projects consistently fail.

The objective of this study is to first, determine the generic risks that can be encountered by a project. A list …

Behavior Of Advanced Innovative Materials For Improved Long-Term Bridge Performance, Wei Zheng

Doctoral Dissertations

"The dissertation is to present the investigation results and comprehensive understanding of the long-term performance and behavior of innovative construction materials. The materials are applied in bridge engineering in order to either enhance the conventional materials or replace them. The dissertation consists of two major parts: structural steel coatings for corrosion mitigation and thermal behavior of concrete bridge.

In First Part, evaluation of advanced structural steel coatings was carried out through laboratory weathering tests (salt-fog resistance test and QUV weathering test), adhesion test, and electrochemical techniques. Fifteen coating systems were evaluated in this part, which covered both coating and recoating …

Decreasing Time To Market For A Medical Device: New Methods For The Product Development Process, Kelly Marie Davis

Doctoral Dissertations

"Through an example, led at a leading medical device company, this dissertation will demonstrate that by applying certain lean principals and tools to the development of a medical device, shortened development times can be obtained. The two papers presented in the dissertation will fill a gap in current literature. Literature presents lean techniques and applications used in many different industries. But, due to the uniqueness of the medical device industry, these general techniques are not ideal. New methods will be used and validated at a medical device company, Covidien. Instead of trying to implement many general lean principals to their …

Design And Experimental Study Of Turbo Equalization For Multiple Antenna Systems, Amirhossein Rafati

Doctoral Dissertations

"Multiple-input multiple-output (MIMO) wireless communication systems have attracted a lot of interest in the past decade due to their capability in delivering high spectral efficiency as well as their robust performance against fading. In MIMO inter-symbol interference (lSI) channels, a severe interference problem occurs due to the lSI and co-channel interference. Thus, the error propagation problem becomes more serious, and its mitigation has to be considered when designing the receiver. In this regard, a turbo equalizer which exchanges soft information between the equalizer and the decoder has been shown to be an effective method to combat the lSI caused by …

Discrete Fiber-Reinforced Polyurea Systems For Infrastructure Strengthening And Blast Mitigation, Natalia L. Carey

Doctoral Dissertations

"The research presented in this dissertation focused on evaluating the effectiveness of various blast mitigation materials and coating technologies to be used for enhancing blast resistance of structural members. Mechanical properties and blast mitigation performance of different discrete fiber-reinforced polyurea (DFRP) systems were investigated through experimental and analytical work. Four technical papers discuss the research efforts conducted within this dissertation.

The first paper examined the development and characterization of different DFRP systems for infrastructure strengthening and blast retrofit. The behavior of various systems which consisted of chopped E-glass fibers discretely integrated in with the polyurea matrix was evaluated through coupon …

Development Of Third Generation Advanced High Strength Steels, Meghan C. Mcgrath

Doctoral Dissertations

"Lightweight duplex steels with combinations of either bainite, acicular ferrite, and austenite or martensite and austenite were investigated as third generation advanced high strength steels targeted for automotive applications. Large additions of manganese (>13 wt%) and carbon (

Duplex steels with different volume fractions of primary δ -ferrite were used to study the crystallography of austenite formed during the peritectic reaction. Solute profiles across the peritectic interface showed aluminum segregated near the interface which promoted bainitic ferrite formation. Thermal treatments were used to manipulate the concentration and type of oxides and the ferrite plate density was found to correlate …

Economics And Finance On Time Scales, Julius Severin Heim

Doctoral Dissertations

"This thesis consists of 6 papers that investigate models in economics and finance based on so-called dynamic equations on time scales. The first paper covers multiplier-accelerator models that can be described by linear second-order dynamic equations. The possibility of taxes as well as the possibility of foreign trade is taken into consideration. The second paper discusses cobweb models, which describe cyclical supply and demand in markets, where the supply is determined before the observation of the price. Cobweb models that can be formulated with first-order linear, second-order linear, and nonlinear dynamic equations are being considered. The third and fourth papers …

Experimental Investigations Of Pseudospark Discharge And Pseudospark Produced Intense Electron Beams, Jing Hu

Doctoral Dissertations

"This dissertation focuses on the pseudospark discharge, a pulsed discharge discovered for the first time in 1970's. This dissertation is prepared as three journal articles in the style used by Missouri University of Science and Technology. A high voltage pseudospark discharge experiment setup, and discharge and electron beam diagnostic system are constructed and presented in this work. Three journal articles which have been published or are under review are presented in this dissertation on various topics of the pseudospark discharge.

Paper 1 "Experimental investigation of formation time in single-gap pseudospark discharge" is focused on experimental investigations of the time-dependent characteristics …

Friction Stir Welding Of High Temperature Alloys, Jiye Wang

Doctoral Dissertations

"Friction stir welding (FSW) of Ti-6Al-4V alloy, nickel-based and iron-based oxide dispersion strengthened (ODS) alloys (MA754 and MA956) has been studied. The main aspects covered include tool evaluation, microstructural evolution, mechanical properties, and correlation between processing, microstructure and mechanical properties. Tool performance study was carried out for Ti-6Al-4V alloy with refractory tools made of W-1.1%La₂O₃ and two different grades of WC-Co based materials. The results showed that tool degradation can be attributed to mechanical and chemical interaction with processed material. The nature of tool-workpiece interaction was tool material dependent and influenced the resultant microstructure and weld quality in the stirred …

Impact Of Plug-In Hybrid Electric Vehicles On The Power Grid In A Smart Environment, Zahra Darabi

Doctoral Dissertations

This dissertation focuses on the interactions between plug-in hybrid electric vehicles (PHEVs) and the power grid. This study has used the data available through the national household travel survey (NHTS) to obtain realistic information such as the arrival time of vehicles, miles driven, and vehicles types. After data manipulation, the aggregated PHEV charging load profiles (PCLP) have been developed. The results show that the peak of PCLP overlaps with the domestic load peak. In order to alleviate this issue, several charging policies have been developed and their impacts on PCLP have been investigated. As a next contribution, the data obtained …

Identification And Visualization Of Electromagnetic Coupling Paths & Nonlinear Capacitors For Esd Protection, Hongyu Li

Doctoral Dissertations

"The first topic of this dissertation focuses on developing methods to identify and visualize electromagnetic coupling paths. The basis of the approach is to utilize an analogy between electromagnetic energy flow and fluid flow. This allows one to apply the theories and algorithms of fluid dynamics to electromagnetics and thereby to visualize the electromagnetic energy flow. This in turn can be utilized to identify the electromagnetic coupling path.

The second topic of this dissertation investigates the nonlinearity of capacitors and suggests improved trade-off between electrostatic discharge (ESD) protection and data bandwidth by using the antiferroelectric (AFE) capacitors as ESD protection. …

Influence Of Microstructural Length Scale On Deformation Behavior Of Magnesium Alloys, Wei Yuan

Doctoral Dissertations

"Friction stir processing (FSP) is emerging as an effective tool for microstructural modification. Mg-Al-Zn alloys with different aluminum contents were subjected to FSP to achieve fine grained and ultrafine grained (UFG) structure. The objective of this work was to study the influence of microstructural length scale on the governing deformation and strengthening mechanisms of FSP magnesium alloys.

FSP introduced strong basal fiber texture and processing parameter dependent grain/precipitate size and distribution. Grain refinement promoted non-basal dislocation activation at room temperature. The strength of the alloy increased as a consequence of grain refinement following classic Hall-Petch relationship to different extents due …

Influence Of Temperature And Microstructural Modification On Formability Of Magnesium Alloys, Arun Mohan

Doctoral Dissertations

"The ß-precipitate free AZ31, ß-precipitate rich AZ91 and a few Mg-Y-Zn alloys were studied to understand the dependence of Mg formability on microstructural condition and temperature. Friction stir processing (FSP) was used to refine the grain size and to obtain desirable distribution of precipitates in the matrix. Since Mg alloys exhibit challenges in achieving room temperature formability, superplastic deformation was utilized. This work focused on high strain rate superplasticity (HSRS, ≥10⁻² s⁻¹) which is more attractive for industrial applications as compared to the slower rates of conventional superplasticity.

Thermally stable fine grains and pinning particles at HSRS temperatures were essential …

Handel's Maser-Solution Theory Of Ball Lightning: The Creation Of Stable Three-Dimensional Cavitons By An Atmospheric Maser With An Open Resonator, Glenn Andrew Carlson

Doctoral Dissertations

"This dissertation develops details of Handel's Maser-Soliton Theory of ball lightning. The atmosphere between a thundercloud and the Earth's surface is modeled as an idealized stable open resonator with water vapor as the active medium and the thundercloud and Earth's surface as reflecting surfaces. The stable resonator generates a maser beam that narrows to the beam waist at the Earth's surface, which is assumed to be planar. Two candidate rotational transitions are identified within the v₁v₂v₃ = 010 vibrational band of water having wavelengths of 13.9 cm and 1.12 cm, and relevant spectroscopic parameters are retrieved from the HITRAN 2008 …

Imaging The Subsurface In Karst Terrain Using Electrical Resistivity Tomography, Evgeniy V. Torgashov

Doctoral Dissertations

"Five electrical resistivity tomography (resistivity) case studies are presented. The first case study, entitled "Springfield Underground", includes ERT data acquired with the purpose of imaging the ceiling of an limestone aggregate mine following simultaneous localized roof failure. The interpretation of the ERT data indicates roof rock failure occurred at the intersection of two previously unmapped near-vertical solution-widened fractures.

At the "Chesterfield Dam" site, resistivity data were acquired to identify the zone of seepage through an earthfill dam. The seepage pathway beneath the dam is interpreted as through a solution-widened fracture, the top of which constituted a segment of the original …

Investigation Of Different Approaches To Combine Cable Information And Near-Field Scan Data For Radiated-Field Estimation, Keong W. Kam

Doctoral Dissertations

"Near-field scanning is often used to solve EMC problems. Aside from the purpose of visualization of near-fields, measured near-field data can be used to estimate far-field. One of many challenges associated with using near-field to far-field transform (NFFFT) technique for EMC application is the handling of attached cables. The objective of this investigation is to evaluate different methods to add cable information to the near-field data for far-field estimation. The investigation is carried out using numerical experiments in EMCoS EMC studio, which is a commercial MoM (Method of Moment) tool for EM simulation. Measurement results from a test structure are …

Small Sample Inference For Exponential Survival Times With Heavy Right-Censoring, Noroharivelo Volaniaina Randrianampy

Doctoral Dissertations

"We develop a saddlepoint-based method and several generalized Bartholomew methods for generating confidence intervals about the rate parameter of an exponential distribution in the presence of heavy random right-censoring. Butler's conditional moment generating function formula is used to derive the relevant moment generating function for the rate parameter score function which provides access to a saddlepoint-based bootstrap method. Moment generating functions also play a key role in the generalized Bartholomew methods we develop. Since heavy censoring is assumed, the possible non-existence of the rate parameter maximum likelihood estimate (MLE) is nonignorable. The overwhelming majority of existing methods condition upon the …

Therapeutic Effects Of N-Acetylcysteine Amide In The Treatment Of Eye Disorders, Joshua W. Carey

Doctoral Dissertations

"The loss of vision from age-related eye diseases now affects over 30 million people in the United States and is expected to reach twice that number within the next couple of decades. Among these disorders, age-related macular degeneration and cataract formation represent the largest percentage of these cases. Therapeutic options available for treating age-related macular degeneration are limited and there is no noninvasive form of treatment for cataracts current available. Several studies have indicated that oxidative stress plays an important role in the pathology of these age-related eye disorders. If oxidative stress is responsible for the initiation and progression of …

Yin Yang Bipolar Atom - An Eastern Road Toward Quantum Gravity, Wen-Ran Zhang

Computing: Faculty Publications

Based on bipolar dynamic logic and bipolar quantum linear algebra, a causal theory of YinYang bipolar atom is introduced in a completely background independent geometry that transcends spacetime. The causal theory leads to an equilibrium-based super symmetrical quantum cosmology of negative-positive energies. It is contended that the new theory has opened an Eastern road toward quantum gravity with bipolar logical unifications of particle and wave, matter and antimatter, relativity and quantum entanglement. Information recovery after a black hole is discussed. It is shown that not only can the new theory be applied in physical worlds but also in logical, mental, …

Beyond Spacetime Geometry – The Death Of Philosophy And Its Quantum Reincarnation, Wen-Ran Zhang

Computing: Faculty Publications

Contrary to the “end” and “death” assertions on philosophy, this paper predicts an equilibrium-based and harmony-centered scientific reincarnation of philosophy. Logically, the reincarnation is backed by a formal system and a background independent geometry that transcends spacetime. Physically, it is supported by definable quantum causality and bipolar logical unifications of matter and antimatter, particle and wave, big bang and black hole, relativity and quantum entanglement. Philosophically, it is distinguished from Western metaphysics and dialectics as well as the Dao of Laozi. It is named a quantum reincarnation for its central claim that YinYang bipolar quantum entanglement is the source of …

Theoretical Studies Of Few-Body Problems, Uttam Chowdhury

Doctoral Dissertations

"Heavy ion collisions with atomic and molecular targets produce many outcomes. The Schrödinger equation is not analytically soluble for more than two mutually interacting particles. As a result, theory must resort to using approximations, the validity of which is determined by comparison with experiment. This work is focused on finding better approximations to describe ionization and capture processes in proton collisions.

Proton-impact ionization of molecular hydrogen is treated as a 3-body problem. Usually the target is treated as an atomic target and the results are multiplied by an ad hoc factor to account for the molecular structure. Measured cross sections …

Two Essays On The Domain Translation From Financial Options To Real Options, Hongyan Chen

Doctoral Dissertations

"Real options (ROs) extend the financial option pricing theory to the valuation of real asset investment and managerial flexibility under uncertainty. However, differences between financial and non-financial markets, and the complex real world environment of applications, build obstacles for the domain translation from financial options to ROs.

This dissertation is motivated by the challenges of domain translation and developed in two essays. The first essay studies the incentive function of ROs (named the RO incentive). The essay develops an option-game framework to model the RO incentive, examines the change of investment behavior caused by the RO incentive, and values the …

Underground Mine Fire Simulation Using Multiscale Modeling Approach, Xichen Zhang

Doctoral Dissertations

"Underground mine fires have always been a major concern. Past events show that fire poses a severe safety hazard to mine workers, and causes tremendous economic loss to the mine and surrounding communities. A good understanding of the interaction between a mine fire and the mine ventilation network is crucial for effective fire emergency planning and hazard control. Unfortunately our understanding of a fire is still limited due to the complex nature of mine fires and a lack of adequate resource for studying them.

A new multiscale modeling approach coupling conventional 1D and 3D techniques has shown to be a …

2012 Fall Commencement, Georgia Southern University

Commencement Programs

No abstract provided.

The Banyan Tree [Volume 6, Number 2], Alan Altany

Faculty Center: News & Publications

Excerpt: "We at the CTLS thank all those faculty who participate regularly or even periodically in our professional faculty development program. At this time we extend an open invitation to those who do not attend any of our activities or join any of our faculty groups. You are encouraged to participate in some way in the program. Many colleagues find such participation, based largely on interdisciplinary collegiality, to be intellectually stimulating, worthwhile, enjoyable, applicable, and socially beneficial."

Formative Research On Hpv Vaccine Acceptability With Latina Farmworkers, John S. Luque, Heide Castañeda, Dinorah Martinez Tyson, Natalia Vargas, Meade

Community Health: Faculty Publications

The purpose of this study was to identify the barriers and benefits to human papillomavirus (HPV) vaccination in a low-income, Latina farmworker population in central Florida. This study reports on formative qualitative research conducted on perceptions of benefits, barriers, costs, place, and promotion related to the HPV vaccine from surveys and interviews with a sample of 46 low-income, Latina farm workers and 19 health care workers serving this population. It was found that Latina farmworkers hold many misperceptions about the HPV vaccine and the potential links between HPV infection and cervical cancer. In addition, it was observed that HPV vaccination …

Formative Research On Perceptions Of Biobanking: What Community Members Think, John S. Luque, Gwendolyn P. Quinn, Francisco A. Montel-Ishino, Mariana Arevalo, Shalanda A. Bynum, Shalewa Noel-Thomas, Kristen J. Wells, Clement K. Gwede, Cathy D. Meade, Tampa Bay Community Cancer Network Partners

Community Health: Faculty Publications

Preparing healthy community members with timely communications prior to engaging them in a request to donate biospecimens promises to improve the experience of biobanking participation. To this end, a qualitative study was conducted to assess community member knowledge, attitudes, beliefs, and informational needs about cancer-related biospecimen collection in a large metropolitan area in southwest Florida. The study utilized purposive sampling techniques to recruit a total of 95 participants to participate in 12 focus groups, segmented by race/ethnicity and language preference (mixed race, African American only, and Spanish speaking) and age (18–29, 30–54, and 55 and older). Focus group interviews were …

Refinement Of An Educational Toolkit To Promote Cervical Cancer Screening Among Hispanic Farmworker Women In Southeast Georgia, Lisa C. Watson-Johnson, Jigar Bhagatwala, Claudia Reyes-Garcia, Andrea Hinojosa, Mondi Mason, Cathy Meade, John S. Luque

Community Health: Faculty Publications

Cervical cancer incidence and mortality continue to affect Hispanic women in the U.S. disproportionately. Our project sought to refine a cervical cancer intervention designed for use by community health workers, or promotoras, in rural southern Georgia. We collaborated with Hispanicpromotoras to refine a Spanish language educational flipchart featuring cervical cancer topic areas for use in screening promotion.