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Graduate Theses, Dissertations, and Problem Reports (ETD)

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Failure Mechanisms In Impact Erosion Of Ductile Materials, Ramesh Padavala Aug 2004

Failure Mechanisms In Impact Erosion Of Ductile Materials, Ramesh Padavala

Graduate Theses, Dissertations, and Problem Reports (ETD)

Solid particle erosion in ductile materials is a common problem in many industrial applications. It is defined as material loss resulting from the mechanical contact between the particle and the metal surface. Many experimental studies were reported in the past to determine the loss of the material due to these ductile impacts. Conducting experiments for numerous materials at different conditions is difficult and costly. A finite element model to predict the ductile erosion loss at various conditions for different materials is more expedient.;In this thesis a finite element model was developed to predict the erosion loss for AL 6061-T0 at …

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Dynamic Modal Analysis And Optimization Of C-130 Project Oculus' Mechanical Arm/Pod Sensor Deployment System Using The Finite Element Method, Adam C. Naternicola Aug 2004

Dynamic Modal Analysis And Optimization Of C-130 Project Oculus' Mechanical Arm/Pod Sensor Deployment System Using The Finite Element Method, Adam C. Naternicola

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Department of Defense (DoD) and the United States Army National Guard (USARNG) have sponsored West Virginia University's Center for Industrial Research Applications (CIRA) to design, fabricate, test and optimize an articulating, mechanical arm/pod system. The mechanical arm/pod system will be designed to accommodate a 500-pound sensor payload deployable in flight from a C-130 Hercules military aircraft used for counter narco-terrorism efforts. During the overall deployment (translation and rotation) of the mechanical arm/pod system and in the final resting position for optimal operating conditions for the data acquisition sensors (DAS), the mechanical structure will be subjected to a variety of …

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Characterization Of Pyrolysis Products From End-Of-Life Electronic Equipment, Venkatadri E. Thiruvallur Aug 2004

Characterization Of Pyrolysis Products From End-Of-Life Electronic Equipment, Venkatadri E. Thiruvallur

Graduate Theses, Dissertations, and Problem Reports (ETD)

Tertiary Recycling of End-of-Life electronic equipment such as computer monitor casings and disk drives is considered in this project. This research aim's at finding new recycling processes that have a possibility for economic scale-up. The present work was divided into two parts. The first one dealt with the investigation of two mixed-plastics streams provided by MBA Polymers (MBAP). One of the streams consisted of fines (MBAP-1), and the other was a non-separable stream, MBAP-2. These solid polymer streams from MBAP were reacted in a Tubular Reactor inerted with helium. The overall objective of these reactions is to determine the process …

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Evaluation Of Concrete Bridge Deck Overlays, Zhenhua Sun Aug 2004

Evaluation Of Concrete Bridge Deck Overlays, Zhenhua Sun

Graduate Theses, Dissertations, and Problem Reports (ETD)

Overlay systems have been used by many states for the protection of bridge decks, but the premature delaminations and failures have been observed in many cases. A comprehensive study was recently defined to investigate overlay performance in collaboration with the West Virginia Department of Transportation-Division of Highways (WVDOH).;As part of a comprehensive program, the present study is concerned with the properties of several types of overlay mixtures and the interface bond strengths between them and substrate concrete. All the materials used are of interests to WVDOH. Both fresh and hardened concrete properties of seven different overlay types were characterized. Four …

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Honeycomb Fiber-Reinforced Polymer Sandwich Composites For Development Of Aquaculture Raceway Systems, Avinash Vantaram Aug 2004

Honeycomb Fiber-Reinforced Polymer Sandwich Composites For Development Of Aquaculture Raceway Systems, Avinash Vantaram

Graduate Theses, Dissertations, and Problem Reports (ETD)

It is argued that the utilization of impaired mine waters abundant in WV and other mid-Appalachian states for fish culture can substantially increase aquaculture economic development. The primary limitation to the effective utilization of discharged waters is the lack of suitable fish culture tanks that can be easily installed in rugged terrains surrounding mine water treatment plants, where cast-in-place concrete tanks cannot be constructed. Therefore, Fiber-Reinforced Polymer (FRP) sandwich materials offer an economical option for production of light, transportable and durable fish culture raceway systems. This study is concerned with the development and evaluation of prototype fish culture tanks using …

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Particle Breakage In Sand Blasting Due To Impact On Ductile Materials, Ravi Kishore Bandaru Aug 2004

Particle Breakage In Sand Blasting Due To Impact On Ductile Materials, Ravi Kishore Bandaru

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cleaning of rust, paint or removing burrs and many other such applications are done by several processes. Sand blasting is one of them, where a stream of sand particles is forcefully projected onto a surface, with compressed air or steam. These sand particles break up into very small pieces upon impact, which are inhaled by workers to cause silicosis. While much research has been done on the surface being impacted, very little research has been done on the particle itself. Hence, proper analytical modeling of the sand blasting process from the particle perspective, validated by experimental results, is required to …

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Influence Of Rearrangement Of Actin Cytoskeleton On The Overall Material Properties Of Atdc5 Cells During Chondrogenesis, Madhavi V. S. Ayyalasomayajula Aug 2004

Influence Of Rearrangement Of Actin Cytoskeleton On The Overall Material Properties Of Atdc5 Cells During Chondrogenesis, Madhavi V. S. Ayyalasomayajula

Graduate Theses, Dissertations, and Problem Reports (ETD)

Studies show that when chondrocytes are cultured in 2D, they lose their phenotype. This change is reversed when the cells are embedded in a 3D culture system such as in agarose gel. Previous experiments in our lab showed that when prechodrocytic cells were embedded in agarose, chondrogenesis was triggered in these cells. This work attempts to understand the mechanical implications of this behavior. It also provides an estimate of the sensitivity of the apparatus that would be required to carry out compression loading experiments of gel-cell constructs that can distinguish between pre-chondrocytes and chondrocytes.;ATDC5 cells were cultured in 3D for …

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Acoustical And Flow Characteristics Of A Cough As An Index Of Pulmonary Function In The Guinea Pig, Joshua W. Day Aug 2004

Acoustical And Flow Characteristics Of A Cough As An Index Of Pulmonary Function In The Guinea Pig, Joshua W. Day

Graduate Theses, Dissertations, and Problem Reports (ETD)

Human studies indicate that cough sound and flow analysis may be useful for diagnosing pulmonary abnormalities. The purpose of this study was to evaluate an animal model for cough sound and flow analysis. A system was designed to expose guinea pigs to aerosols of citric acid (0.39M) and record resulting coughs at different stages of chemically induced specific airway resistance (sRAW). Coughs were divided into three categories (low sRAW, n = 113; moderate sRAW, n = 143; high sR AW, n = 93). 124 cough sound parameters were derived from the analysis of the sound pressure waves recorded during the …

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Reduction Of Natural Gas Engine Emissions Using A Novel Aftertreatment System, Timothy S. Burlingame Aug 2004

Reduction Of Natural Gas Engine Emissions Using A Novel Aftertreatment System, Timothy S. Burlingame

Graduate Theses, Dissertations, and Problem Reports (ETD)

The global objective of this study was to develop an exhaust aftertreatment system to reduce gaseous and particulate matter emissions from natural gas fueled vehicles. Specific objectives of this study were to evaluate and characterize emissions from a natural gas fueled vehicle powered by a Cummins C8.3G+ engine with and without the particulate matter (PM) filter and oxidation catalyst (OC) combination, which was designed and developed by West Virginia University in collaboration with Lubrizol-ECS. Central Business District (CBD) Cycle tests were performed on West Virginia University's Transportable Emissions Testing Laboratory. A heavy-duty transportable chassis dynamometer and a dedicated "clean" dilution …

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Feature-Level Fusion In Multimodal Biometrics, Rohin K. Govindarajan Aug 2004

Feature-Level Fusion In Multimodal Biometrics, Rohin K. Govindarajan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Multimodal biometric systems utilize the evidence presented by multiple biometric modalities (e.g., face and fingerprint, multiple fingers of a user, multiple impressions of a single finger, etc.) in order to determine or verify the identity of an individual. Information from multiple sources can be consolidated in three distinct levels [1]: (i) feature set level; (ii) match score level; and (iii) decision level. While fusion at the match score and decision levels have been extensively studied in the literature, fusion at the feature level is a relatively understudied problem. A novel technique to perform fusion at the feature level by considering …

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Effects Of Artificial Neural Network Speed-Based Inputs On Heavy-Duty Vehicle Emissions Prediction, Nastaran Hashemi Aug 2004

Effects Of Artificial Neural Network Speed-Based Inputs On Heavy-Duty Vehicle Emissions Prediction, Nastaran Hashemi

Graduate Theses, Dissertations, and Problem Reports (ETD)

The PM split study was performed in Southern California on thirty-four heavy-duty diesel vehicles using the West Virginia University Transportable Heavy-Duty Vehicle Emissions Testing Laboratories to gather emissions data of these vehicles. The data obtained from six vehicles in the 1985--2001 model year and 33,000--80,000 lb weight range exercised through three different cycles were selected in this thesis. To predict the instantaneous levels of oxides of nitrogen (NOx), carbon dioxide (CO2), hydrocarbons (HC) and carbon monoxide (CO), an Artificial Neural Network (ANN) was used. Axle speed, torque, their rates of change over different time periods and two other variables as …

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Electrochemical Impedance Spectroscopy Of Proton Exchange Membrane Fuel Cell Stacks, Brian J. Hetzer Aug 2004

Electrochemical Impedance Spectroscopy Of Proton Exchange Membrane Fuel Cell Stacks, Brian J. Hetzer

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electrochemical Impedance Spectroscopy (EIS) is applied to a small, four cell Proton Exchange Membrane (PEM) fuel cell stack to examine the stack response as the load current changes. The measured stack response is compared to a simulated response generated by a stack model that has been developed using MATLAB. The results show that the model predicted well the behavior of the VI curve for currents less than 50 Amps. The model also qualitatively predicted the impedance response as a function of current and frequency. Because of apparent model incompleteness, it was not able to predict accurately the shape of the …

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Coal Desulfurization With Sodium Hypochlorite, Wei Li Aug 2004

Coal Desulfurization With Sodium Hypochlorite, Wei Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

Wet desulfurization of Pittsburgh No. 8 coal and Illinois No. 6 coal were conducted with sodium hypochlorite in the laboratory. Pittsburgh No. 8 coal was leached by hypochlorite at high pHs in one step only. The hypochlorite concentration varied from 0.2 to 0.6 molar; sodium hydroxide concentration, from 0.2 to 0.8 molar; and temperature was at the levels of 80 and 90°C. The desulfurization of Illinois No. 6 coal was conducted in three consecutive steps of pretreatment in concentrated ammonia at room temperature, leaching with hypochlorite at room temperature and hydrolysis in a sodium hydroxide solution at 90°C. In the …

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Chemical And Physical Modification Of Petroleum, Coal-Tar, And Coal-Extract Pitches By Air-Blowing, Nathan D. King Aug 2004

Chemical And Physical Modification Of Petroleum, Coal-Tar, And Coal-Extract Pitches By Air-Blowing, Nathan D. King

Graduate Theses, Dissertations, and Problem Reports (ETD)

Treatment by air-blowing was pursued as a process to modify the properties of pitches. The focus of this research was to compare the effects of air-blowing a coal-extract pitch with a petroleum pitch and coal-tar binder pitch. Hydrogenation of a bituminous coal in tetralin was used to produce the coal-extract pitch. The three pitches were air-blown in a 1-liter autoclave at temperatures of 250°C, 275°C, and 300°C for various time periods. The air-blown pitches were then characterized by softening point, coke yield, solubility, viscosity, density, elemental analysis, thermogravimetric analysis, FTIR, and optical texture. The results showed that air-blowing was a …

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Software Quality And Reliability Prediction Using Dempster -Shafer Theory, Lan Guo Aug 2004

Software Quality And Reliability Prediction Using Dempster -Shafer Theory, Lan Guo

Graduate Theses, Dissertations, and Problem Reports (ETD)

As software systems are increasingly deployed in mission critical applications, accurate quality and reliability predictions are becoming a necessity. Most accurate prediction models require extensive testing effort, implying increased cost and slowing down the development life cycle. We developed two novel statistical models based on Dempster-Shafer theory, which provide accurate predictions from relatively small data sets of direct and indirect software reliability and quality predictors. The models are flexible enough to incorporate information generated throughout the development life-cycle to improve the prediction accuracy.;Our first contribution is an original algorithm for building Dempster-Shafer Belief Networks using prediction logic. This model has …

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Adaptive Video Segmentation, Nagamani Banda Aug 2004

Adaptive Video Segmentation, Nagamani Banda

Graduate Theses, Dissertations, and Problem Reports (ETD)

The efficiency of a video indexing technique depends on the efficiency of the video segmentation algorithm which is a fundamental step in video indexing. Video segmentation is a process of splitting up a video sequence into its constituent scenes. This work focuses on the problem of video segmentation. A content-based approach has been used which segments a video based on the information extracted from the video itself. The main emphasis is on using structural information in the video such as edges as they are largely invariant to illumination and motion changes. The edge-based features have been used in conjunction with …

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Hydrologic Investigation Of Three Constructed Mitigation Wetlands And One Natural Wetland In West Virginia, Scott A. Copen Aug 2004

Hydrologic Investigation Of Three Constructed Mitigation Wetlands And One Natural Wetland In West Virginia, Scott A. Copen

Graduate Theses, Dissertations, and Problem Reports (ETD)

The goal of this study was to increase the probability of success for future mitigation wetland projects by performing a hydrologic investigation at three constructed mitigation wetland sites and one natural reference wetland site. In addition, a numerical groundwater model was developed for a portion of one of the constructed mitigation wetlands.;Hydrologic, meteorologic, topographic, and geotechnical data were collected at three constructed mitigation wetlands and one reference natural wetland. Hydrologic data were collected using monitoring wells, piezometers, automated water level recorders, and a water level meter. Meteorologic data were obtained from the National Oceanic and Atmospheric Administration's weather station in …

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Tcp/Ip Stack Fingerprinting For Patch Detection In A Distributed Windows Environment, Balaji Ganesan Aug 2004

Tcp/Ip Stack Fingerprinting For Patch Detection In A Distributed Windows Environment, Balaji Ganesan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Patch Management has become important in every system administrator's work profile. A missing patch can be essentially considered a vulnerability as the hackers make use of the knowledge of the vulnerability from the security bulletin and attempt attacks for that vulnerability. An efficient patch management solution is necessary to counter known vulnerabilities. For this an inventory listing of the patches installed in each system called a patch audit helps the system administrators know the patch status and install only the necessary patches. An important problem in patch auditing is that there may be many systems in a network for which …

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Developing The Portability Indices And The Portable Code Generator, Gregory E. Mundy Aug 2004

Developing The Portability Indices And The Portable Code Generator, Gregory E. Mundy

Graduate Theses, Dissertations, and Problem Reports (ETD)

Portability is recognized as a highly desirable characteristic of contemporary software design. However, research in the area has not been forthcoming in recent years and much of the work related to the field is ad hoc and speculative at best.;This study attempted to establish a framework for deriving a probabilistic measure of software portability that may be useful in aiding developers to make key design decisions that will result in some quantifiable level of portability while minimizing the cost of incorporating portable design into the software production process.;The research also explored the potential portability benefits that may be derived from …

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Diagnosis Of Operational Changes In Microelectromechanical Systems Via Fault Detection, Scott A. Rittenhouse Aug 2004

Diagnosis Of Operational Changes In Microelectromechanical Systems Via Fault Detection, Scott A. Rittenhouse

Graduate Theses, Dissertations, and Problem Reports (ETD)

As microelectromechanical systems (MEMS) devices migrate into progressively more critical systems, the reliability these devices have to demonstrate must increasingly improve. Current research in the reliability of MEMS has succeeded in increasing the reliability of commercialized MEMS before they are integrated into an application by focusing on fabrication processes, device materials, and packaging. In this study, the focus is on assessing the reliability of MEMS during device operation.;A fault detection approach was taken to diagnose incipient changes in the operation of MEMS devices. Model-based fault detection schemes utilizing the Kalman filter and Hinfinity filter as residual generators were investigated. Analysis …

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Theoretical And Experimental Analysis Of Frp Bridge Decks Under Thermal Loads, Krit Laosiriphong Aug 2004

Theoretical And Experimental Analysis Of Frp Bridge Decks Under Thermal Loads, Krit Laosiriphong

Graduate Theses, Dissertations, and Problem Reports (ETD)

The temperature difference between the top and bottom of a fiber reinforced polymer (FRP) composite deck (120°F) is nearly three times that of conventional concrete decks (40°F). The large temperature difference is attributed to low thermal conductivity of FRP material and low thermal mass due to hollow core. Thermal response studies have been conducted for FRP bridge decks under thermal fluctuations and temperature difference across the deck depth.;In this study, thermal tests were conducted on two FRP bridge deck modules (4&inches; and 8&inches; deep decks) in the laboratory by heating or cooling at the top surface of FRP deck (i.e., …

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Effects Of Various Phytase Concentrations In Diets With Low-Phytate Corn On Broiler Chick Performance And Metabolism, Nicole J. Baker Aug 2004

Effects Of Various Phytase Concentrations In Diets With Low-Phytate Corn On Broiler Chick Performance And Metabolism, Nicole J. Baker

Graduate Theses, Dissertations, and Problem Reports (ETD)

Research indicates a reduction of phosphorus content in fecal excreta with the supplementation of phytase to corn-soybean meal based diets or with the use of low phytate corn (LPC) in broilers. This study examined how 0--3 wk broiler chicks are impacted by concomitant phytase supplementation with LPC (0.136% phytate phosphorus (PP) by analysis) in the diet. Various levels of phytase from either 2500 or 5000 FYT/g of Peniophora lycii phytase product were used as experimental treatments. Efficacy of treatments was determined using a response curve created with increasing levels of monocalcium phosphate. Following a 6-day pretest, 576 broiler chicks were …

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Effect Of Grain Particle Size, Feed Form And Pellet Texture On Broiler Performance, Carcass Quality, True Metabolizable Energy, Feed Passage Time And Preference, Amy S. Parsons Aug 2004

Effect Of Grain Particle Size, Feed Form And Pellet Texture On Broiler Performance, Carcass Quality, True Metabolizable Energy, Feed Passage Time And Preference, Amy S. Parsons

Graduate Theses, Dissertations, and Problem Reports (ETD)

Treatments consisted of five mash diets (781 microns, 950 microns, 1,042 microns, 1,109 microns, 2,242 microns) and two pelleted diets (water (soft) and binder (hard) inclusion). Water and binder addition produced similar pellet durability (90.4% and 86.2% respectively) and fines (44.5% and 40.3% respectively).;Broilers fed mash diets exhibited decreased live weight gain and breast yield with increased gizzard, compared to broilers fed pelleted diets. As diet particle size increased, feed intake and gizzard yield increased and feed efficiency decreased. Broiler true metabolizable energy increased then decreased when diet particle size increased. Hard pellets increased live weight gain. Fines of the …

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Effectiveness Of Trek-21 Model Of Professional Development On Changes In Teacher Practices With Respect To Instructional Technology Integration, Chifundo N. Lemani Aug 2004

Effectiveness Of Trek-21 Model Of Professional Development On Changes In Teacher Practices With Respect To Instructional Technology Integration, Chifundo N. Lemani

Graduate Theses, Dissertations, and Problem Reports (ETD)

The purpose of this study was to investigate the relationship between key factors of Trek-21 professional development model and resulting changes in teacher practices with respect to the integration of instructional technologies into participants' classrooms. The Trek 21 professional development was a three-year project designed to bring about a deep and lasting change in educators through the integration of instructional technologies. The project was funded as an implementation grant through the U.S. Department of Education's Preparing Tomorrow's Teachers to Use Technology (PT3) grant program. The Trek-21 professional development was developed around research-based practices that enabled participants to develop IT skills …

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Silicon Carbide Epitaxial Growth Using Methylsilanes As Gas Sources, Charlie Y. Peng Aug 2004

Silicon Carbide Epitaxial Growth Using Methylsilanes As Gas Sources, Charlie Y. Peng

Graduate Theses, Dissertations, and Problem Reports (ETD)

Large area and high quality SiC substrates are required for many applications. The goal of this research is to develop novel methods of growing epitaxial silicon carbide (SiC) on 6H-SiC and silicon (Si) substrates while extending our understanding of the growth mechanisms and the effects of key growth parameters. High temperature hydrogen-etching procedures for preparing atomically-stepped 6H-SiC substrates suitable for epitaxial growth were also developed.;This dissertation presents results of both homoepitaxial SiC growth on 6H-SiC substrates and heteroepitaxial growth on Si substrates by gas source molecular beam epitaxy. The experimental variables included gas species, molecular flux, growth time, and substrates …

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Numerical Simulation Of Fine Particle Separation In Hindered -Settling Bed Separators By Computational Fluid Dynamics, Yunkai Xia Aug 2004

Numerical Simulation Of Fine Particle Separation In Hindered -Settling Bed Separators By Computational Fluid Dynamics, Yunkai Xia

Graduate Theses, Dissertations, and Problem Reports (ETD)

The objective of the present study was to improve the understanding of multiple phase flows in hindered-settling bed separators (HSBS). A better understanding of mineral separation in HSBS and the role of structured plates was gained through studies conducted with Computational Fluid Dynamics (CFD) analysis tools. An Euler-Lagrange model from CFD technique is used for this purpose.;In an Euler-Lagrange model, two dimensional incompressible Navier-Stokes equations are solved with the implementation of a finite volume approach over staggered grids with application of Baldwin-Lomax turbulent model. The overall accuracy of the method is second-order in both space and time. The calculation of …

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Biologically Inspired Evolutionary Temporal Neural Circuits, Reza Derakhshani Aug 2004

Biologically Inspired Evolutionary Temporal Neural Circuits, Reza Derakhshani

Graduate Theses, Dissertations, and Problem Reports (ETD)

Biological neural networks have always motivated creation of new artificial neural networks, and in this case a new autonomous temporal neural network system. Among the more challenging problems of temporal neural networks are the design and incorporation of short and long-term memories as well as the choice of network topology and training mechanism. In general, delayed copies of network signals can form short-term memory (STM), providing a limited temporal history of events similar to FIR filters, whereas the synaptic connection strengths as well as delayed feedback loops (ER circuits) can constitute longer-term memories (LTM). This dissertation introduces a new general …

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Information Dissemination By Compounding, Bohe (Bob) Wang Aug 2004

Information Dissemination By Compounding, Bohe (Bob) Wang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Gossiping and broadcasting are two problems of information dissemination. In gossiping, every point in the network knows a unique item of information and needs to communicate it to all other points. Most of the recent interest in gossiping is due to its importance in the area of network communications and other areas of parallel and distributed computing.;Determining precisely the values of the minimum number of edges in a gossip graph is known to be a very hard problem. Very few values are known in the general case. G. Fertin and R. Labahn[Fer00],[FL00] used the k-way compounding method to construct gossip …

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Performance Study In The Hydrotreatment Of Coal With Coal-Derived Solvents, Manoj Katakdaunde Aug 2004

Performance Study In The Hydrotreatment Of Coal With Coal-Derived Solvents, Manoj Katakdaunde

Graduate Theses, Dissertations, and Problem Reports (ETD)

Hydrotreatment of coal in the presence of hydrogen donor solvents is considered to be a potential route for developing value-added carbon products. The aim of this research was to investigate the use of coal-derived solvents as replacements for expensive hydrogendonor solvents like tetralin, in the production of hydrogen rich carbon products. Three coal-derived solvents obtained from the metallurgical coke ovens, namely Heavy Creosote Oil (HCO), Carbon Black Base (CBB) and Refined Chemical Oil (RCO), were utilized as hydrogen donor solvents in the hydrotreatment process. The coal-alone conversion in producing THF solubles decreased in the order as CBB>HCO>RCO. Process-derived …

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Operant Conditioning In Older Adults With Alzheimer's Disease, Adam P. Spira Aug 2004

Operant Conditioning In Older Adults With Alzheimer's Disease, Adam P. Spira

Graduate Theses, Dissertations, and Problem Reports (ETD)

Behavioral interventions are commonly implemented to manage agitation in older adults with dementia. However, the extent to which operant conditioning can occur in this population is unclear. The present study used a button-pressing task to evaluate the sensitivity of the responding of individuals with probable Alzheimer's disease to changes in schedules of reinforcement. Results indicate that operant conditioning can occur in older adults with AD. Specifically, three participants with AD exhibited responding that was highly sensitive to a transition from a fixed interval schedule to an extinction schedule. One participant's responding was sensitive to a more subtle transition. Comparison data …

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