Digital Commons Network^™

Analysis And Optimization Of Dynamic Spectrum Sharing For Cognitive Radio Networks, Manish Wadhwa

Electrical & Computer Engineering Theses & Dissertations

The goal of this dissertation is to present the analysis and optimization of dynamic spectrum sharing for cognitive radio networks (CRNs). Spectrum scarcity is a well known problem at present. In order to deal with this problem, dynamic spectrum sharing (DSS) was proposed. DSS is a technique where cognitive radio networks dynamically and opportunistically share the channels with primary users. The major contribution of this dissertation is in analyzing the problem of dynamic spectrum sharing under different scenarios and developing optimal solutions for these scenarios. In the first scenario, a contention based dynamic spectrum sharing model is considered and its …

Simulation Studies Of Pulsed Voltage Effects On Cells, Jiahui Song

Electrical & Computer Engineering Theses & Dissertations

This dissertation research focuses on the new field of pulsed electric field interactions with biological cells. In particular, "Intracellular Electromanipulation" which has important biomedical applications, is probed. Among the various aspects studied, nanosecond, high-intensity pulse induced electroporation is one phenomena. It is simulated based on a coupled scheme involving the current continuity and Smoluchowski equations. A dynamic pore model can be achieved by including a dependence on the pore population density and a variable membrane tension. These changes make the pore formation energy E(r) self-adjusting and dynamic in response to pore formation. Additionally, molecular dynamics (MD) simulations are also discussed …

Experimental Investigation Of A Non-Thermal Atmospheric Pressure Plasma Jet, Asma Begum

Electrical & Computer Engineering Theses & Dissertations

The main objective of this dissertation is to understand the formation of the plasma jet from the plasma pencil, and the propagation of the plasma jet in the ambient atmosphere where the effect of the external electric field is almost zero. Before investigating the formation and propagation phenomenon of the plasma jet, common physical properties of plasma jets are determined by using the imaging technique and optical emission spectroscopy. The first goal of this dissertation is to establish the laminar helium gas flow channel through a plasma pencil.

The formation position, formation time, and the criterion of the plasma jet …

The Effect Of Adding Organic Polymers On The Handling Properties, Strengths And Bioactivity Of A Ca-Sr-Zn-Si Glass Polyalkenoate Cement, A. W. Wren, N. M. Cummins, A. Coughlan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

This work demonstrates the addition of a number of naturally occurring proteins/polymers to a zinc-based glass polyalkenoate cements (GPCs). Chitin (Chi.), collagen (Col.), cysteine (Cys.) and keratin (Ker.) were added with the intention of improving the bioactivity of this cement. Initial testing involved characterization of the glass with X-ray diffraction (XRD) and differential thermal analysis (DTA) before and after sterilization with γ-irradiation. No significant changes occurred as a result of sterilization. Handling properties of the modified cements were not significantly different from those of the control, BT 101 (Working T_w-36_s, and setting time T_s-70 …

Development Of Pilot Plant For Bio-Ethanol Processing, Emrod Elisante

Tanzania Journal of Engineering and Technology (TJET)

The paper outlines achievements obtained in developing a pilot bio-ethanol plant at the Department of Chemical and Mining Engineering (CME), University of Dar es Salaam. The pilot plant consists of: 30 L inoculums tank; 1,700 L fermenter; 1,500 L/day distillation column; and ancillary equipment. The prototype is a platform intended to be used for technology demonstration and research by graduate and undergraduate students studying the production of bio-ethanol using traditional and non-traditional raw materials like coffee mash, cashew fruit, and sisal inulin. The equipment has been developed using locally available engineering resources and the distillation column with 18 sieve tray …

Gold Nanoparticles And Their Polymer Composites: Synthesis Characterization And Applications, Nidhi Joshi

USF Tampa Graduate Theses and Dissertations

Gold nanoparticles are excellent candidates for all the biomedical applications due to their size and shape dependent optical and physiological properties. In this study, gold nanoparticles were synthesized chemically for bio-application. It was observed that the size and shape of gold nanoparticles depend strongly on the concentration of chemical solution, type of reducing agent used in the reaction, temperature of the solution and stabilizing agent for reaction. Transmission electron microscopy (TEM) has been used extensively to determine the size and shape of the gold nanoparticles. Optical properties of the size and shape selected nanoparticles were studied using UV-vis spectrophotometer in …

The Structure And Stability Of Alpha-Helical, Orthogonal-Bundle Proteins On Surfaces, Shuai Wei

Theses and Dissertations

The interaction of proteins with surfaces is a major problem involved in protein microarrays. Understanding protein/surface interactions is key to improving the performance of protein microarrays, but current understanding of the behavior of proteins on surfaces is lacking. Prevailing theories on the subject, which suggest that proteins should be stabilized when tethered to surfaces, do not explain the experimentally observed fact that proteins are often denatured on surfaces. In an attempt to develop some predictive capabilities with respect to protein/surface interactions, it was asked in previous works if the stabilization/destabilization of proteins on surfaces could be correlated to secondary structure …

Synthesis, Characterization, And Self-Assembly Of Gold Nanorods And Nanoprisms, Kristina L. Tran

USF Tampa Graduate Theses and Dissertations

The unique properties of gold nanoparticles make them excellent candidates for applications in electronics, sensing, imaging, and photothermal therapy. Though abundant literature exists for isotropic gold nanoparticles, work on nanoparticles of different shapes has been gaining interest recently. Anisotropic gold nanoparticles, such as nanorods and nanoprisms, have tunable optical properties in the visible and near-infrared regions. Through synthesis and surface modification, the production of various shapes of these gold nanoparticles can be controlled to meet different applications.

Two different types of gold nanorods were used in this thesis. The first type was stabilized with cetyltrimethylammonium bromide (CTAB) and had aspect …

Ant Colony Optimization Algorithm For Robot Path Planning, Michael Brand, Michael Masuda, Nicole Wehner, Xiao-Hua Yu

Electrical Engineering

Path planning is an essential task for the navigation and motion control of autonomous robot manipulators. This NP-complete problem is difficult to solve, especially in a dynamic environment where the optimal path needs to be rerouted in real-time when a new obstacle appears. The ACO (Ant Colony Optimization) algorithm is an optimization technique based on swarm intelligence. This paper investigates the application of ACO to robot path planning in a dynamic environment. Two different pheromone re-initialization schemes are compared and computer simulation results are presented.

Atomic-Level Investigation Of Surface Processes Governing Sige Wetting Layer Formation Using Stm/Sts, Kyle J. Solis

Chemical and Biological Engineering ETDs

Upon sub-monolayer Ge deposition on the 2xn reconstructed SiGe alloy wetting layer at room temperature, the predominant adspecies observed are so-called addimer chain structures (ADCSs). Polarity-switching scanning tunneling microscopy (STM) is used to study ADCSs, as they only appear in empty-state images. ADCSs are dilute structures comprising type-C addimers that reside in neighboring troughs and extend along all equivalent < 130> directions of the surface, giving rise to a zigzagged morphology. ADCSs exhibit localized movements, wherein their rearrangements are strongly coupled with the structure of the underlying substrate dimers. At elevated temperatures, ADCSs are observed to transition to compact epitaxial segments of …

The Sintering And Stability Of Catalytic Nano-Particles, Andrew Delariva

Chemical and Biological Engineering ETDs

Studies were performed on three different catalysts in order to determine their stability and sintering behavior. Pd deposited on a flat single crystal substrate made of Al2O3 was characterized to determine if the mechanism of Ostwald ripening was solely dominated by vapor phase transport of metal atoms. The atoms emitted could be determined by the rate of evaporation and an attempt was then made in order to relate the rates of emission to sintering (instability of nanoparticles). It was found that the rates of emission did not fully reflect vapor phase transport (direct evaporation). The particle-support interaction was increasing the …

Long-Term Desorption Behavior Of Uranium And Neptunium In Heterogeneous Volcanic Tuff Materials, Dean Cynthia

Chemical and Biological Engineering ETDs

Uranium and neptunium desorption were studied in long-term laboratory experiments using four well-characterized volcanic tuff cores collected from southeast of Yucca Mountain, Nevada. The objectives of the experiments were to 1. Demonstrate a methodology aimed at characterizing distributions of sorption parameters (attributes of multiple sorption sites) that can be applied to moderately-sorbing species in heterogeneous systems to provide more realistic reactive transport parameters and a more realistic approach to modeling transport in heterogeneous systems. 2. Focus on uranium and neptunium because of their high solubility, relatively weak sorption, and high contributions to predicted dose in Yucca Mountain performance assessments. Also, …

Piezoresistive Nano-Composites: Characterization And Applications, Thomas B. Hyatt

Theses and Dissertations

Innovative multifunctional materials are essential to many new sensor applications. Piezoresistive nano-composites make up a promising class of such materials that have the potential to provide a measurable response to strain over a much wider range than typical strain gages. Commercial strain gages are currently dominated by metallic sensors with a useable range of a few percent strain at most. There are, however, many applications that would benefit from a reliable wide-range sensor. These might include the study of explosive behavior, instrumentation of flexible components, motion detection for compliant mechanisms and hinges, human-technology interfaces, and a wide variety of bio-mechanical …

A Natural Language To Component Term Methodology: Towards A Form Based Concept Generation Tool, Matt Robert Bohm, Robert B. Stone

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Over the last few decades design researchers have put forward theories and proposed methodologies that increase the chance that a design team will reliably arrive at the optimal solution to a given design problem. Studies, however, bear out that theories and methodologies alone will not guarantee an optimal or even good design solution. Instead, a breadth of knowledge across multiple engineering domains and the time and tools to thoroughly evaluate the design space are as important as any prescriptive design method. This work presents one of the underlying engineering technologies needed to leverage artificial intelligence approaches to thoroughly search the …

Bioadhesion To Model Thermally Responsive Surfaces, Brett J. Andrzejewski

Chemical and Biological Engineering ETDs

This dissertation focuses on the characterization of two surfaces: mixed self-assembled monolayers (SAMs) of hexa(ethylene glycol) and alkyl thiolates (mixed SAM) and poly(N-isopropylacrylamide) (PNIPAAm). The synthesis of hexa(ethylene gylcol) alkyl thiol (C11EG6OH) is presented along with the mass spectrometry and nuclear magnetic resonance results. The mixed SAM surface was confirmed to be thermally responsive by contact angle goniometry, 35° at 28 °C and 55° at 40 °C. In addition, the mixed SAM surfaces were confirmed to be thermally responsive for various aqueous mediums by tensiometry. Factors such as oxygen, age, and surface mole fraction and how they affect the thermal …

Ultrasound Transient Shear Wave Elasticity Imaging For Tendon Tissue, Pengfei Song

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Degeneration of tendon tissue is a common cause of tendon dysfunction with the symptoms of repeated episodes of pain and palpable increase of tendon thickness. Tendon mechanical properties are directly related to its physiological composition and the structural organization of the interior collagen fibers which could be altered by tendon degeneration due to overuse or injury. Thus, measuring mechanical properties of tendon tissue may represent a quantitative measurement of pain, reduced function, and tissue health. Ultrasound elasticity imaging has been developed in the last two decades and has proved to be a promising tool for tissue elasticity imaging. To date, …

Bioinformatics Data Mining Using Artificial Immune Systems And Neural Networks, Shane Dixon, Xiao-Hua Yu

Electrical Engineering

Bioinformatics is a data-intensive field of research and development. The purpose of bioinformatics data mining is to discover the relationships and patterns in large databases to provide useful information for biomedical analysis and diagnosis. In this research, algorithms based on artificial immune systems (AIS) and artificial neural networks (ANN) are employed for bioinformatics data mining. Three different variations of the real-valued negative selection algorithm and a multi-layer feedforward neural network model are discussed, tested and compared via computer simulations. It is shown that the ANN model yields the best overall result while the AIS algorithm is advantageous when only the …

Numerical Approach For Quantification Of Epistemic Uncertainty, John Jakeman, Michael Eldred, Dongbin Xiu

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

In the field of uncertainty quantification, uncertainty in the governing equations may assume two forms: aleatory uncertainty and epistemic uncertainty. Aleatory uncertainty can be characterised by known probability distributions whilst epistemic uncertainty arises from a lack of knowledge of probabilistic information. While extensive research efforts have been devoted to the numerical treatment of aleatory uncertainty, little attention has been given to the quantification of epistemic uncertainty. In this paper, we propose a numerical framework for quantification of epistemic uncertainty. The proposed methodology does not require any probabilistic information on uncertain input parameters. The method only necessitates an estimate of the …

Optical Measurement Of Environmental Uranium Using Porous Silica Materials, Chien-Cheng Chen

Theses and Dissertations

The focus of this research is on the optical measurement of uranyl in a solid matrix using fluorescence spectroscopy. Nanoporous silica-based materials were used to extract uranyl from contaminated soil and to enhance the fluorescence intensity and lifetime. The fluorescence lifetime and intensity of uranyl ions adsorbed on porous silica-based materials of varying pore size was measured as a function of pH and in the presence of fluoride. The feasibility of uranyl fluorescence detection on the top of soil by silica gel is carried out by four types of natural soil. The results show that the uranyl fluorescence intensity can …

Mission Assurance: A Review Of Continuity Of Operations Guidance For Application To Cyber Incident Mission Impact Assessment (Cimia), Brian L. Hale

Theses and Dissertations

Military organizations have embedded information technology (IT) into their core mission processes as a means to increase operational efficiency, improve decision-making quality, and shorten the sensor-to-shooter cycle. This IT-to-mission dependence can place the organizational mission at risk when an information incident (e.g., the loss or manipulation of a critical information resource) occurs. Non-military organizations typically address this type of IT risk through an introspective, enterprise-wide focused risk management program that continuously identifies, prioritizes, and documents risks so an economical set of control measures (e.g., people, processes, technology) can be selected to mitigate the risks to an acceptable level. The explicit …

Architectural Considerations For Single Operator Management Of Multiple Unmanned Aerial Vehicles, Gabriel T. Bugajski

Theses and Dissertations

Recently, small Unmanned Aircraft Systems (UAS) have become ubiquitous in military battlefield operations due to their intelligence collection capabilities. However, these unmanned systems consistently demonstrate limitations and shortfalls with respect to size, weight, range, line of sight and information management. The United States Air Force Unmanned Aircraft Systems Flight Plan 2009-2047 describes an action plan for improved UAS employment which calls out single operator, multi-vehicle mission configurations. This thesis analyzes the information architecture using future concepts of operations, such as biologically-inspired flocking mechanisms. The analysis and empirical results present insight into the engineering of single-operator multiple-vehicle architectures.

Use Of Negation In Search, Kristen M. Lancaster

Theses and Dissertations

Boolean algebra was developed in the 1840s. Since that time, negation, one of the three basic concepts in Boolean algebra, has influenced the fields of information science and information retrieval, particularly in the modern computer era. In Web search engines, one of the present manifestations of information retrieval, little use is being made of this functionality and so little attention is given to it in the literature. This study aims to bolster the understanding of the use and usefulness of negation. Specifically, an Internet search task was developed for which negation was the most appropriate search strategy. This search task …

Direct Mapping Ovsf-Based Transmission Scheme For Underwater Acoustic Multimedia Communication, Chin-Feng Lin, Jiang-Yao Chen, Ya-Ju Yu, Jung-Ting Yan, Shung-Hyung Chang

Journal of Marine Science and Technology–Taiwan

We would like to express our appreciation to the people that provided their help during this study. We also extend our appreciation to Dr. Chang-tai Shih, Visiting Professor of National Taiwan Ocean University from the Canadian Mu- seum of Nature, for his critical review and comments on the manuscript. This study was financially supported by a grant (NSC94-2313-B-019-018 and 94AS-14.1.1-FA-F1(16)) from the National Science Council of the Republic of China and the Fisheries Agency, Council of Agriculture, Taiwan, R.O.C.

Genetic Algorithm-Based Chaos Clustering Approach For Nonlinear Optimization, Min-Yuan Cheng, Kuo-Yu Huang

Journal of Marine Science and Technology–Taiwan

In this paper, a n-dimension convergence algorithm was employed to track the potential trend of evolution in traditional genetic algorithm (GA) by K-means clustering technique. And, chaotic algorithm was exploited to prevent the new approach from premature. By means of the proposed approach, not only the basic search capability was maintained but also the flexibility and efficiency of parametric modeling were improved. The main purpose of the paper is to demonstrate how the GA optimizer can be improved by incorporating a hybridization strategy. Experimental studies revealed that the hybrid chaotic approach with genetic algorithm (CGA) procedure could produce much more …

A Full-Range, Multi-Variable, Cfd-Based Methodology To Identify Abnormal Near-Wall Hemodynamics In A Stented Coronary Artery, Jonathan Murphy, Fergal Boyle

Articles

The benefit of coronary stent implantation is reduced by excessive intimal hyperplasia which re-narrows the artery and the prevention of which is still a primary concern for clinicians. Abnormal hemodynamics create non-physiological viscous stress on the artery wall, one of the root causes of intimal hyperplasia following stent implantation. A methodology to comprehensively evaluate the viscous stress on the artery wall following stent implantation would be useful to evaluate a stent’s hemodynamic performance. The proposed methodology employs 3D computational fluid dynamics, the variables wall shear stress (WSS), WSS gradient (WSSG), WSS angle gradient (WSSAG) and a statistical analysis to evaluate …

Cell Culture Method And Apparatus For Mechanically Stimulating Cells, Seth W. Donahue

Michigan Tech Patents

A cell culture assembly and a method for culturing cells that provide mechanical stimulation to cells. The cell culture assembly can include a flow chamber positioned in a fluid path and a support comprising cells positioned within the flow chamber to expose the cells to the fluid path. The cell culture assembly can further include a means for producing a steady flow of fluid in the fluid path, and a means for producing an oscillatory flow of fluid in the fluid path simultaneously with producing the steady flow of fluid in the fluid path to mechanically stimulate the cells. The …

Advanced Biofuels: Commercializing The Efficient Syngas-To-Ethanol Platform, Wes Bolsen

CO2 Summit: Technology and Opportunity

No abstract provided.

Abstracts Of Oral Presentations

CO2 Summit: Technology and Opportunity

Abstracts of Oral Presentations and Keynote Lectures

How To Make Cement And Concretes With Lower Co2 Emissions, Ellis Gartner

CO2 Summit: Technology and Opportunity

No abstract provided.

Enhanced Photosynthetic Growth, Biodiesel And Electricity Production Using C. Vulgaris And P. Putida/S. Cerevisiae, Pranabendu Mitra

CO2 Summit: Technology and Opportunity

No abstract provided.