Digital Commons Network^™

Novel Techniques For Selective Doping Of Silicon Carbide For Device Applications, Bharat Krishnan

Theses and Dissertations

Superior properties of Silicon Carbide (SiC), such as wide bandgap, high breakdown field and high thermal conductivity, have made it the frontrunner to replace Silicon for applications requiring high breakdown strength, mechanical and radiation hardness. Commercial SiC devices are already available, although their expected performance has not yet been realized due to a few problems related to device fabrication technologies, such as selective doping. This work explores non-traditional techniques for SiC doping (and selective doping in particular) based on previously unknown types of defect reactions in SiC and novel epitaxial growth techniques, which offer advantages over currently available technologies. Recent …

Osteogenic Regulatory Mechanisms Activated By Pressure In Aortic Heart Valve, Carol Andrea Pregonero Gamez

Theses and Dissertations

Calcific aortic valve disease (CAVD) is the most common cause of aortic valve failure and replacement in the elderly population, affecting 25% of the population over 65 years of age. Current pharmacological approaches for preventing the onset and progression of calcific aortic valve disease have not shown consistent benefits in clinical studies. Differentiation of valvular interstitial cells (VICs) into osteoblast–like cells is an integral step in the calcification process. Although clinical evidence suggests hypertension as a potential candidate contributing to the development of CAVD, the underlying molecular mechanisms that cause de-differentiation remain unclear. The present study investigates the role of …

Parallel Viterbi Search For Continuous Speech Recognition On A Multi-Core Architecture, Naveen Parihar

Theses and Dissertations

State-of-the-art speech-recognition systems can successfully perform simple tasks in real-time on most computers, when the tasks are performed in controlled and noiseree environments. However, current algorithms and processors are not yet powerful enough for real-time large-vocabulary conversational speech recognition in noisy, real-world environments. Parallel processing can improve the real-time performance of speech recognition systems and increase their applicability, and developing an effective approach to parallelization is especially important given the recent trend toward multi-core processor design. In this dissertation, we introduce methods for parallelizing a single-pass across-word n-gram lexical-tree based Viterbi recognizer, which is the most popular architecture for Viterbi-based …

Partitioning And Interface Requirements Between System And Application Control For Power Electronic Converter Systems, Anil Kumar Kondabathini

Theses and Dissertations

Applications of power electronics in power systems are growing very rapidly and changing the power system infrastructure in terms of operation speed and control. Even though applications of power electronics are wide spread, the cost and reliability of power electronics are the issues that could hinder their penetration in the utility and industrial systems. The demand for efficient and reliable converter controllers gave rise to modularized converter and controller design. The objective of this dissertation is to determine the appropriate partitioning and interface requirements between the system and application control layers for power electronic converters so that the minimum set …

Implantable Antennas For Wireless Data Telemetry: Design, Simulation, And Measurement Techniques, Tutku Karacolak

Theses and Dissertations

Recent advances in electrical engineering have let the realization of small size electrical systems for in-body applications. Today’s hybrid implantable systems combine radio frequency and biosensor technologies. The biosensors are intended for wireless medical monitoring of the physiological parameters such as glucose, pressure, temperature etc. Enabling wireless communication with these biosensors is vital to allow continuous monitoring of the patients over a distance via radio frequency (RF) technology. Because the implantable antennas provide communication between the implanted device and the external environment, their efficient design is vital for overall system reliability. However, antenna design for implantable RF systems is a …

Information Processing System To Security Standard Compliance Measurement: A Quantitative Approach Using Pathfinder Networks (Pfnets), Elaine Hulitt

Theses and Dissertations

Continuously changing system configurations and attack methods make information system risk management using traditional methods a formidable task. Traditional qualitative approaches usually lack sufficient measurable detail on which to base confident, cost-effective decisions. Traditional quantitative approaches are burdened with the requirement to collect an abundance of detailed asset value and historical incident data and to apply complex calculations to measure the data precisely in work environments where there are limited resources to collect and process it. To ensure that safeguards (controls) are implemented to protect against a majority of known threats, industry leaders are requiring information processing systems to comply …

Small Signal And Transient Stability Analysis Of Mvdc Shipboard Power System, Seetharama Raju Rudraraju

Theses and Dissertations

Recent developments in high power rated Voltage Source Converters (VSCs) have resulted in their successful application in Multi-Terminal HVDC (MTDC) transmission systems and also have potential in the Medium Voltage DC (MVDC) distribution systems. This work presents the findings of stability studies carried out on a zonal MVDC architecture for the shipboard power distribution system. The stability study is confined to rotor angle stability of the power system, i.e. the transient and small signal stability analysis. The MTDC ring structure similar to MVDC shipboard power system was implemented in MATLAB/Simulink to look at the transient behavior of the MVDC system. …

Validated Prediction Of Pressurant Gas Requirements In Cryogenic Run Tanks At Subcritical And Supercritical Pressures, Laurence De Quay

Theses and Dissertations

The development, testing, and use of liquid propellant and hybrid rocket propulsion systems for spacecraft and their launch vehicles routinely involves the use of cryogenic propellants. These propellants provide high energy densities that enable high propulsive efficiency and high engine thrust to vehicle weight ratios. However, use of cryogenic propellants also introduces technical problems not associated with other types of propellants. One of the major technical problems is the phenomenon of propellant tank pressurant and ullage gas collapse. This collapse is mainly caused by heat transfer from most of the ullage gas to tank walls and interfacing propellant, which are …

Verification Of A Three-Dimensional Statics Model For Continuum Robotics And The Design And Construction Of A Small Continuum Robot (Scr), Ricky (Ricky Lee) Gray

Theses and Dissertations

Continuum robots are biologically inspired robots that capture the extraordinary abilities of biological structures such as elephant trunks, octopus tentacles, and mamma-lian tongues. They are given the term continuum robots due to their ability to bend conti-nuously rather than at specific joints such as with traditional rigid link robots. They are used in applications such as search and rescue operations, nuclear reactor repairs, colo-noscopies, minimal invasive surgeries, and steerable needles. In this thesis, a model that predicts the shape of a continuum robot is presented and verified. A verification system to verify the validity and accuracy of the model is …

Real Time Modeling, Simulation And Validation Of Protective Relays, Ankush Saran

Theses and Dissertations

The protection system plays an important role in the power system to detect the fault, isolate the faulted zone from the unaulted zone and restore the power supply to the healthy part. In order to validate the developed protection system, hardware in the loop (HIL) tests have been performed on several power system test cases using commercial overcurrent and distance relays from two vendors and a Real Time Digital Simulator (RTDS). Two-bus and eight-bus terrestrial power systems (TPS) as well as a 4-bus shipboard power system (SPS) are developed in RSCAD and used as power system test cases. The simulation …

Machine Learning-Based Ontology Mapping Tool To Enable Interoperability In Coastal Sensor Networks, Shruthi Bheemireddy

Theses and Dissertations

In today’s world, ontologies are being widely used for data integration tasks and solving information heterogeneity problems on the web because of their capability in providing explicit meaning to the information. The growing need to resolve the heterogeneities between different information systems within a domain of interest has led to the rapid development of individual ontologies by different organizations. These ontologies designed for a particular task could be a unique representation of their project needs. Thus, integrating distributed and heterogeneous ontologies by finding semantic correspondences between their concepts has become the key point to achieve interoperability among different representations. In …

The Murray Ledger And Times, December 11, 2009, The Murray Ledger And Times

The Murray Ledger & Times

No abstract provided.

Clinical Profile, Outcomes And Improvement In Symptoms And Productivity In Rhinitic Patients In Karachi, Pakistan., Taimur Saleem, Umair Khalid, Ubaid Ur Rehman Sherwani, Shehzad Ghaffar

Section of Otolaryngology, Head & Neck Surgery

Background:Rhinitis can cause a heavy toll on Patients because of its bothersome effects on productivity. This retrospective study was conducted to explore the clinical profile, outcomes and improvement in the symptoms and productivity resulting from treatment of allergic rhinitis in Pakistan.

Methods:

We carried out a retrospective file review of all allergic rhinitis Patients who presented to the Ear, Nose, Throat Consulting Clinic from January, 2006 to June, 2008 using a structured proforma especially designed for this Purpose. Data was entered and analyzed using SPSS v. 16.0.

Results:

The charts of 169 Patients were reviewed. The mean age of …

Synthesis Of Local Thermo-Physical Models Using Genetic Programming, Ying Zhang

USF Tampa Graduate Theses and Dissertations

Local thermodynamic models are practical alternatives to computationally expensive rigorous models that involve implicit computational procedures and often complement them to accelerate computation for real-time optimization and control. Human-centered strategies for development of these models are based on approximation of theoretical models. Genetic Programming (GP) system can extract knowledge from the given data in the form of symbolic expressions. This research describes a fully data driven automatic self-evolving algorithm that builds appropriate approximating formulae for local models using genetic programming. No a-priori information on the type of mixture (ideal/non ideal etc.) or assumptions are necessary.

The approach involves synthesis of …

Filtration Performance Of A Niosh-Approved N95 Filtering Facepiece Respirator With Stapled Head Straps, Daniel E. Medina

USF Tampa Graduate Theses and Dissertations

Certain models of NIOSH-approved filtering facepiece air purifying respirators are manufactured with stapled head straps. Depending on the manufacturer, these head straps may be stapled to the filter media itself. This may cause leakage through the filter media of the respirator, potentially exposing the user to an unacceptable level of contaminant. In this study, monodisperse polystyrene latex (PSL) spheres were generated to challenge four replicates of a N95 single use respirator model made by the same manufacturer.

Nominal particle sizes of the PSL spheres used to challenge the respirators were 0.5, 1, and 2 micrometers in diameter. All respirators were …

Mobile Computing And Sensor Web Services For Coastal Buoys, Santhosh Kumar Amanchi Rajender

Theses and Dissertations

Mobile device technology with the influence of the Internet is creating a lot of Webbased services so that people can have easy and 24-hour access to the services. Recently, the Google’s Android has revolutionized applications development for the mobile platform. As there is an increasing number of companies exposing their services as Web services, enabling flexible mobile access to distributed Web resources is a relevant challenge. However, the current Web is a collection of human readable pages that are unintelligible to computer programs. Semantic Web and Web services have the potential of overcoming this limitation. For this, a standard ontology …

An Assessment Of Flow Quality In An Open Test Section Wind Tunnel, Christopher Eric Hamm

Theses and Dissertations

The subsonic wind tunnel facility at Mississippi State University has been converted to an open test section configuration. An experimental setup was developed which is easily configurable to allow for further research. Measurements of flow quality over select portions of the test section were made to attain a basic understanding of the performance of the new configuration. A program was developed in LabVIEW to control a 3-axis traverse and perform necessary data reduction. The traverse control program was developed to perform data acquisition using a hotilm probe to facilitate the necessary measurements. Data was gathered at two wind tunnel velocity …

The Importance Of Soft Skills In The Workplace As Perceived By Community College Instructors And Industries, Laura Suzanne Tribble

Theses and Dissertations

Soft skills include communication skills, problem-solving skills, conflict resolution, working well with other people, and ensuring customer satisfaction. Employers need employees who have adequate technical skills but who also have soft skills. There is limited information about the perceptions of which soft skills are needed in the workplace. This study attempted to close the gap in the literature concerning the perceptions of instructors and employers in the area of soft skills in the workplace. For this study, the Soft Skills Survey for Instructors and Employers was used to gather the perceptions of information technology instructors and employers in five community …

Investigation Of The Mechanical Properties Of Poly (Ethylene Glycol) Diacrylate By Nanoindentation Using Atomic Force Microscopy, Zouheir Drira

Theses and Dissertations

Poly (ethylene glycol) (PEG) hydrogel based polymers are among the most widely used synthetic materials for biomedical applications. Because of their biocompatibility, and ease of fabrication, hydrogels are highly suitable for use as constructs to engineer tissues as well as for cell transplantation. A critical parameter of importance for PEG hydrogels is their mechanical properties which are highly dependent on the environmental conditions. Properties of PEG-based hydrogels can be engineered to resemble scaffolds composed of extracellular matrix molecules, which provide structural support, adhesive sites and mechanical as well as biomechanical signals to most cells. The mechanical properties of these synthetic …

Incorporating Multiresolution Analysis With Multiclassifiers And Decision Fusion For Hyperspectral Remote Sensing, Terrance Roshad West

Theses and Dissertations

The ongoing development and increased affordability of hyperspectral sensors are increasing their utilization in a variety of applications, such as agricultural monitoring and decision making. Hyperspectral Automated Target Recognition (ATR) systems typically rely heavily on dimensionality reduction methods, and particularly intelligent reduction methods referred to as feature extraction techniques. This dissertation reports on the development, implementation, and testing of new hyperspectral analysis techniques for ATR systems, including their use in agricultural applications where ground truthed observations available for training the ATR system are typically very limited. This dissertation reports the design of effective methods for grouping and down-selecting Discrete Wavelet …

Rapid Identification Of Aspergillus Spp. Using A Pcr Based Melting Curve Method And Characterization Of A Novel Chitinase In Insect Resistant Maize Lines, Biing-Ru Wu

Theses and Dissertations

Identification of fungal isolates is critical in studying Aspergillus flavus ecology and for developing methods to reduce aflatoxin contamination. In our efforts to track biocontrol applications of the atoxigenic A. flavus K49 (NRRL 30797), we have developed a rapid and accurate classification system for A. flavus based on PCR product melting temperatures (Tm). Using 18 primers and a total of 59 Aspergilli strains, including all 49 representatives of the Georgian peanut Vegetative Compatibility Groups (VCGs), a decision tree Tm flowchart was generated. The decision tree can classify all 59 strains using only 9 of the SSR primers and an average …

Nutrient Management In On-Site Wastewater Treatment, Ayanangshu Dey

Theses and Dissertations

Groundwater and surface water contamination has been linked in the past to inadequate or failing on-site wastewater treatment and disposal systems. The on-site wastewater systems installed in coastal areas have more potential for inflicting this kind of environmental damage. This work studied the regulatory compliance and environmental protection of the four types of on-site wastewater disposal systems found on the Mississippi Gulf Coast; i.e., vegetative rock filter, subsurface drip irrigation, sand mound, and sprinkler systems, by statistical techniques. Compliance was also evaluated for groundwater samples collected from monitoring wells installed at four corners of a disposal field. This work eventually …

Laser Induced Incandescence And Laser Induced Breakdown Spectroscopy Based Sensor Development, Kemal Efe Eseller

Theses and Dissertations

In this doctoral dissertation, two laser-based sensors were evaluated for different applications. Laser Induced Incandescence (LII) is a technique which can provide nonintrusive quantitative measurement of soot and it provides a unique diagnostic tool to characterize engine performance. Since LII is linearly proportional to the soot volume fraction, it can provide in situ, real time measurement of soot volume fraction with high temporal and spatial resolution. LII has the capability to characterize soot formation during combustion. The soot volume fraction from both flames and a soot generator was investigated with LII. The effects of experimental parameters, such as laser fluence, …

Effects Of River Discharge And Marine Environmental Factors On The Brown Shrimp Fishery In The Northern Gulf Of Mexico, Adam George Pollack

Theses and Dissertations

Regression analyses and delta-lognormal models were used to investigate whether river discharge and environmental variables significantly affected relative abundance of brown shrimp, Farfantepenaeus aztecus, in the northern Gulf of Mexico. Significant negative relationships were found between mean river flow during winter and spring months and catch rates (CPUE) off Texas, Louisiana and Mississippi/Alabama. However, during the same months significant positive relationships between CPUE and the variation in mean river discharge were found for each state. In Texas and Louisiana, delta-lognormal models revealed depth zone was the most significant variable (P≤0.001) in describing distribution, while time of day (P≤0.001) was most …

Advancements In Power System Monitoring And Inter-Operability, Vinoth Mohan Mohan

Theses and Dissertations

In a typical utility control center, there could be hundreds of applications running to take care of day-to-day functionality. In many cases, these applications are custom-built by different vendors. With the expectation for high reliability of the electric power grid, many utilities are increasingly moving towards sharing data with each other and with security coordinators. But this data exchange is hampered by incompatible electrical applications built on proprietary data formats and file systems. Electric Power Research Institute's (EPRI‟s) Common Information Model (CIM) was envisioned as a one-sizeits-all data model to remove incompatibility between applications. This research work utilizes the CIM …

Fractionation Of Soybean Meal, Cottonseed Meal And Wheat Middlings Using Combination Of Sieving And Air Classification, Ravi Kumar Challa

Theses and Dissertations

Fiber separation from these animal feeds could increase the protein and hence increase the value of the animal feed. The objective of the study was to evaluate the combination of sieving and air classification for fiber separation from soybean meal (SBM), cottonseed meal (CSM) and wheat middlings (WM). The effect of yields of lighter fractions on fiber separation from size fractions was also investigated. At low yields of lighter fraction (5%), the quantity of fiber product separated was 3.7, 1.3 and 4.8% by weight of SBM, CSM and WM respectively. At high yields of lighter fractions (15%), the quantity of …

Identification Of Micrornas In Bovine Spermatozoa With Implications Of Fertility, Lashonda S (Lashonda Shakita) Robertson

Theses and Dissertations

MicroRNAs are small RNA molecules that could possibly play a major role in fertility. In the experiment, spermatozoa were extracted from bovine followed by an extraction of total RNA. Bovine spermatozoa were extracted from two bulls of different fertility, high and low fertility. An expression array was done to compare the expression levels of the microRNAs. It was shown that thousands of microRNAs are present in bovine spermatozoa but only a small amount was significantly expressed. The microRNAs from low fertility bulls were more highly expressed than those in high fertility bulls. A Bioanalyzer gel was used to confirm the …

A Method For Integrating Heterogeneous Datasets Based On Go Term Similarity, Chamali Lankara Thanthiriwatte

Theses and Dissertations

This thesis presents a method for integrating heterogeneous gene/protein datasets at the functional level based on Gene Ontology term similarity. Often biologists want to integrate heterogeneous data sets obtain from different biological samples. A major challenge in this process is how to link the heterogeneous datasets. Currently, the most common approach is to link them through common reference database identifiers which tend to result in small number of matching identifiers. This is due to lack of standard accession schemes. Due to this problem, biologists may not recognize the underlying biological phenomena revealed by a combination of the data but by …

A Partial Discharge Measurement Technique For Applied Square Pulse Voltage With 50 Ns Rise Times, Clayborne Dudley Taylor

Theses and Dissertations

During the fabrication of solid electrical insulation, small cavities known as micro voids may form in the material. As electrical stress increases in this micro void, the breakdown probability also increases. This type of electrical breakdown is commonly known as partial discharge. Magnitudes of partial discharge currents are typically small but enough to cause degradation of the electrical insulation. To study degradation for fast-rise time voltage square pulse train, partial discharge measurement is needed. In current studies, partial discharge pulse widths have been measured in the range of nanoseconds. The best approach for measurement at ultra wide band frequencies is …

An Analysis Of The Harvesting Costs And Productivity Of Logging Contractors Within The Eastern United States, Jeffrey Jaudon Smith

Theses and Dissertations

A data set was compiled from detailed information provided from 26 independent logging contractors from throughout the Eastern United States over a five year period from 2000 to 2004. The age distribution of the logging contractors in the study has increased over time with the percentage of contactors over the age of 55 rising from 15% to 32%. The median age of all equipment including feller-bunchers, skidders, loaders, bulldozers, service vehicles, and haul trucks increased over the period. While the median age of all equipment increased, the age of service and support equipment saw the greatest increase. The total average …