Current Search: synthesis (x)
Pages
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Title
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Speech Synthesis Utilizing Microcomputer Control.
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Creator
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Uzel, Joseph N., Patz, Benjamin W., Engineering
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Abstract / Description
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Florida Technological University College of Engineering Thesis; This report explores the subject of speech synthesis. Information given includes a brief explanation of speech production in man, an historical view of speech synthesis, and four types of electronic synthesizers in use today. Also included is a brief presentation on phonetics, the study of speech sounds. An understanding of this subject is necessary to see how a synthesizer must produce certain sounds, and how these sounds are...
Show moreFlorida Technological University College of Engineering Thesis; This report explores the subject of speech synthesis. Information given includes a brief explanation of speech production in man, an historical view of speech synthesis, and four types of electronic synthesizers in use today. Also included is a brief presentation on phonetics, the study of speech sounds. An understanding of this subject is necessary to see how a synthesizer must produce certain sounds, and how these sounds are put together to create words. Finally a description of a limited text speech synthesizer is presented. This system allows the user to enter English text via a keyboard and have it output in spoken form. The future of speech synthesis appears to be very bright. This report also gives some possible applications of verbal computer communication.
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Date Issued
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1978
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Identifier
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CFR0004781, ucf:52972
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFR0004781
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Title
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EXPRESSION MORPHING BETWEEN DIFFERENT ORIENTATIONS.
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Creator
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Fu, Tao, Foroosh, Hassan R., University of Central Florida
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Abstract / Description
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How to generate new views based on given reference images has been an important and interesting topic in the area of image-based rendering. Two important algorithms that can be used are field morphing and view morphing. Field morphing, which is an algorithm of image morphing, generates new views based on two reference images which were taken at the same viewpoint. The most successful result of field morphing is morphing from one person's face to the other one's face. View morphing, which is...
Show moreHow to generate new views based on given reference images has been an important and interesting topic in the area of image-based rendering. Two important algorithms that can be used are field morphing and view morphing. Field morphing, which is an algorithm of image morphing, generates new views based on two reference images which were taken at the same viewpoint. The most successful result of field morphing is morphing from one person's face to the other one's face. View morphing, which is an algorithm of view synthesis, generates in-between views based on two reference views which were taken at different viewpoints for the same object. The result of view morphing is often an animation of moving one object from the viewpoint of one reference image to the viewpoint of the other one.In this thesis, we proposed a new framework that integrates field morphing and view morphing to solve the problem of expression morphing. Based on four reference images, we successfully generate the morphing from one viewpoint with one expression to another viewpoint with a different expression. We also proposed a new approach to eliminate artifacts that frequently occur in view morphing due to occlusions and in field morphing due to some unforeseen combination of feature lines. We solve these problems by relaxing the monotonicity assumption to piece-wise monotonicity along the epipolar lines. Our experimental results demonstrate the efficiency of this approach in handling occlusions for more realistic synthesis of novel views.
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Date Issued
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2004
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Identifier
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CFE0000070, ucf:46110
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0000070
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Title
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ROOM TEMPERATURE SYNTHESIS AND SYSTEMATIC CHARACTERIZATION OF ULTRA-SMALL CERIA NANOPARTICLES.
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Creator
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Patel, Chetak, Santra, Swadeshmukul, University of Central Florida
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Abstract / Description
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Cerium oxide (ceria, CeO2) is a rare earth oxide that has attracted wide-spread research interest because of its unique properties such as high mechanical strength, oxygen ion conductivity, oxygen storage capacity and autocatalytic property. In recent years, researchers have discovered that ceria nanoparticles (NPs) are capable of protecting cells from free radical induced damage. Interestingly, it was found that nanometer size (~ 5 nm) ceria can scavenge free radicals quite efficiently, thus...
Show moreCerium oxide (ceria, CeO2) is a rare earth oxide that has attracted wide-spread research interest because of its unique properties such as high mechanical strength, oxygen ion conductivity, oxygen storage capacity and autocatalytic property. In recent years, researchers have discovered that ceria nanoparticles (NPs) are capable of protecting cells from free radical induced damage. Interestingly, it was found that nanometer size (~ 5 nm) ceria can scavenge free radicals quite efficiently, thus acting as an anti-oxidant. This phenomenon has been explained based on the autocatalytic property of ceria NPs. Several methods have been developed for the synthesis of ceria NPs that include flame combustion, hydroxide co-precipitation, hydrothermal/solvothermal, microemulsion, sonochemical and microwave-assisted heating methods and sol-gel method. Ceria NPs synthesized by these methods are often highly aggregated. Furthermore, large scale synthesis of monodispersed CeO2 NPs is quite challenging. Therefore it is desirable to synthesize ceria NPs in bulk quantity keeping its important properties intact, specifically free-radical scavenging property. The main goal of this study is therefore to synthesize ultra-small (< 5.0 nm), high quality monodispersed ceria NPs in large quantities. In this thesis work, I present a couple of room temperature techniques, dilute sodium hydroxide (NaOH) assisted and ethylenediamine (EN) assisted for the synthesis of nearly mono-dispersed, ultra-small (< 5 nm) and water-dispersible ceria NPs. Morphology and particle size of the ceria NPs were investigated through high resolution transmission electron microscopy (HRTEM). The HRTEM analysis confirmed the formation of 3.0 ± 0.5 nm size and 2.5 ± 0.2 nm size highly-crystalline ceria NPs when synthesized using dilute NaOH and EN as solvents, respectively. The nanostructures were characterized by X-ray diffraction (XRD) studies to determine the crystal structure and phase purity of the products. The samples were also thoroughly characterized by X-ray photoelectron spectroscopy (XPS) to determine the oxidation state of cerium ions. The presence of the +3 and +4 oxidation states in the samples was also confirmed from the XPS analysis. The co-existence of these two oxidation states is necessary for their applications as free radical scavenger. The autocatalytic behaviors of the ceria NPs were investigated through a hydrogen peroxide test and monitored by UV-visible transmission spectroscopy.
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Date Issued
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2009
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Identifier
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CFE0002883, ucf:48043
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0002883
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Title
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SYNTHESIS AND CHARACTERIZATION OF POLYMER-DERIVED POROUS SICN CERAMICS.
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Creator
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wei, yun, An, Linan, University of Central Florida
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Abstract / Description
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The synthesis and characterization of porous SiCN ceramics produced by the method of polymer-derived ceramics were studied in this work. The polymer-to-ceramic conversion technique is a novel revolution in the methods for fabricating porous materials with controlled morphologies and tailored properties. The porous SiCN ceramics can be successfully prepared from thermal decomposition of polymeric precursors (polysilazane) and the pore former (polyvinyl alcohol (PVA)). The fabrication...
Show moreThe synthesis and characterization of porous SiCN ceramics produced by the method of polymer-derived ceramics were studied in this work. The polymer-to-ceramic conversion technique is a novel revolution in the methods for fabricating porous materials with controlled morphologies and tailored properties. The porous SiCN ceramics can be successfully prepared from thermal decomposition of polymeric precursors (polysilazane) and the pore former (polyvinyl alcohol (PVA)). The fabrication procedures involved the mixing of the pre-ceramic precursor with appropriate concentration of the PVA, curing, pyrolysis and subsequent PVA removal, leaving pores in the ceramic matrix. The material obtained revealed a homogeneous amorphous microstructure consisting of Si, C and N elements. The effects of the concentration and the particle size of PVA on the bulk density, open porosity, line shrinkage, microstructure, pore size, permeability, mechanical behavior, oxidation behavior and thermal stability were examined in this thesis. An increase in both concentration and particle size of PVA contribute to a decrease in the bulk density and an increase in the open porosity and line shrinkage. The morphology development, in particular, was investigated by scanning electron microscopy (SEM). The properties in terms of the pore size and permeability were measured by the water expulsion method. The mechanical behavior of the porous SiCN ceramic was characterized by the three- point bending strength test, thermal shock strength test and hertzian indentation strength test. The flexural strength and hertzian indentation strength of these porous ceramics at room temperature decrease with an increase in porosity. However, the flexural strength after thermal shock was significantly improved by increasing the temperature change. The oxidation behavior and thermal stability of porous SiAlCN ceramics were also explored by the mass change versus oxidation time and temperature. The phase evolution at different temperatures was also investigated by XRD analysis.
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Date Issued
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2008
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Identifier
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CFE0002359, ucf:47792
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0002359
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Title
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APPLICATION OF ANTENNA SYNTHESIS AND DIGITAL SIGNAL PROCESSING TECHNIQUES FOR ACTIVE MILLIMETER-WAVE IMAGING SYSTEMS.
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Creator
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Caba, Wilson, Boreman, Glenn, University of Central Florida
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Abstract / Description
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Millimeter-wave imaging has gathered attention in recent years for its ability to penetrate clothing, thin layers of soils, and certain construction materials. However, image quality remains a challenge that needs to be addressed. One way of improving image quality is by increasing the dimensions of the collecting aperture. A sparse array can be used to synthesize a larger aperture with a limited set of relatively small detectors. In this research we design, build, and test a test-bed having...
Show moreMillimeter-wave imaging has gathered attention in recent years for its ability to penetrate clothing, thin layers of soils, and certain construction materials. However, image quality remains a challenge that needs to be addressed. One way of improving image quality is by increasing the dimensions of the collecting aperture. A sparse array can be used to synthesize a larger aperture with a limited set of relatively small detectors. In this research we design, build, and test a test-bed having an active source at 94 GHz and an array of coherent detectors, mounted on arms that extend radially on a rotary table. Using this test bed a circular area with a maximum diameter of 900 mm can be scanned. The signal is down-converted using heterodyne receivers with digital in-phase and quadrature detection. Signal correlation is performed using the digitized data, which is stored for post-processing, electronic focusing, and image reconstruction. Near-field imaging using interferometric reconstructions is achieved using electronic focusing. Imaging tests show the ability of the system to generate imagery of concealed and unconcealed objects at distances between 400 and 700 mm. A study of the effects of redundant and non-redundant configurations on image quality for 4 common detector configurations is presented. In this document we show that an active sparse-aperture imaging system using digital correlators is a viable way to generate millimeter-wave images.
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Date Issued
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2010
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Identifier
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CFE0003406, ucf:48429
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0003406
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Title
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A STATISTICAL APPROACH TO VIEW SYNTHESIS.
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Creator
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Berkowitz, Phillip, Shah, Mubarak, University of Central Florida
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Abstract / Description
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View Synthesis is the challenging problem of predicting a new view or pose of an object given an exemplar view or set of views. This thesis presents a novel approach for the problem of view synthesis. The proposed method uses global features rather than local geometry to achieve an effect similar to that of the well known view morphing method . While previous approaches to the view synthesis problem have shown impressive results, they are highly dependent on being able to solve for epipolar...
Show moreView Synthesis is the challenging problem of predicting a new view or pose of an object given an exemplar view or set of views. This thesis presents a novel approach for the problem of view synthesis. The proposed method uses global features rather than local geometry to achieve an effect similar to that of the well known view morphing method . While previous approaches to the view synthesis problem have shown impressive results, they are highly dependent on being able to solve for epipolar geometry and therefore have a very precise correspondence between reference images. In cases where this is not possible such as noisy data, low contrast data, or long wave infrared data an alternative approach is desirable. Here two problems will be considered. The proposed view synthesis method will be used to synthesis new views given a set of reference views. Additionally the algorithm will be extended to synthesis new lighting conditions and thermal signatures. Finally the algorithm will be applied toward enhancing the ATR problem by creating additional training data to increase the likelihood of detection and classification.
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Date Issued
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2009
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Identifier
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CFE0002684, ucf:48214
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0002684
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Title
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FAST ALGORITHMS FOR FRAGMENT BASED COMPLETION IN IMAGES OF NATURAL SCENES.
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Creator
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Borikar, Siddharth Rajkumar, Pattanaik, Dr.Sumanta, University of Central Florida
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Abstract / Description
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Textures are used widely in computer graphics to represent fine visual details and produce realistic looking images. Often it is necessary to remove some foreground object from the scene. Removal of the portion creates one or more holes in the texture image. These holes need to be filled to complete the image. Various methods like clone brush strokes and compositing processes are used to carry out this completion. User skill is required in such methods. Texture synthesis can also be used to...
Show moreTextures are used widely in computer graphics to represent fine visual details and produce realistic looking images. Often it is necessary to remove some foreground object from the scene. Removal of the portion creates one or more holes in the texture image. These holes need to be filled to complete the image. Various methods like clone brush strokes and compositing processes are used to carry out this completion. User skill is required in such methods. Texture synthesis can also be used to complete regions where the texture is stationary or structured. Reconstructing methods can be used to fill in large-scale missing regions by interpolation. Inpainting is suitable for relatively small, smooth and non-textured regions. A number of other approaches focus on the edge and contour completion aspect of the problem. In this thesis we present a novel approach for addressing this image completion problem.Our approach focuses on image based completion, with no knowledge of the underlying scene. In natural images there is a strong horizontal orientation of texture/color distribution. We exploit this fact in our proposed algorithm to fill in missing regions from natural images. We follow the principle of figural familiarity and use the image as our training set to complete the image.
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Date Issued
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2004
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Identifier
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CFE0000053, ucf:46078
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0000053
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Title
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SYNTHESIS, PROCESSING AND CHARACTERIZATION OF NANOCRYSTALLINE TITANIUM DIOXIDE.
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Creator
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Qiu, Shipeng, Kalita, Samar, University of Central Florida
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Abstract / Description
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Titanium dioxide (TiO2), one of the basic ceramic materials, has found a variety of applications in industry and in our daily life. It has been shown that particle size reduction in this system, especially to nano regime, has the great potential to offer remarkable improvement in physical, mechanical, optical, biological and electrical properties. This thesis reports on the synthesis and characterization of the nanocrystalline TiO2 ceramic in details. The study selected a simple sol-gel...
Show moreTitanium dioxide (TiO2), one of the basic ceramic materials, has found a variety of applications in industry and in our daily life. It has been shown that particle size reduction in this system, especially to nano regime, has the great potential to offer remarkable improvement in physical, mechanical, optical, biological and electrical properties. This thesis reports on the synthesis and characterization of the nanocrystalline TiO2 ceramic in details. The study selected a simple sol-gel synthesis process, which can be easily controlled and reproduced. Titanium tetraisopropoxide, isopropanol and deionized water were used as starting materials. By careful control of relative proportion of the precursor materials, the pH and peptization time, TiO2 nanopowder was obtained after calcination at 400oC. The powder was analyzed for its phases using X-ray powder diffraction (XRD) technique. Crystallite size, powder morphology and lattice fringes were determined using high-resolution transmission electron microscopy (HR-TEM). Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to study the thermal properties. As-synthesized powder was uniaxially compacted and sintered at elevated temperature of 1100-1600oC to investigate the effects of sintering on nano powder particles, densification behavior, phase evolution and mechanical properties. Microstructure evolution as a function of sintering temperature was studied by scanning electron microscopy (SEM). The results showed that 400oC was an optimum calcination temperature for the as-synthesized TiO2 powder. It was high enough to achieve crystallization, and at the same time, helped minimize the thermal growth of the crystallites and maintain nanoscale features in the calcined powder. After calcination at 400oC (3 h), XRD results showed that the synthesized nano-TiO2 powder was mainly in single anatase phase. Crystallite size was first calculated through XRD, then confirmed by HR-TEM, and found to be around 5~10 nm. The lattice parameters of the nano-TiO2 powder corresponding to this calcination temperature were calculated as a=b=0.3853 nm, c=0.9581 nm, α=β=γ=90o through a Rietveld refinement technique, which were quite reasonable when comparing with the literature values. Considerable amount of rutile phase had already formed at 600oC, and the phase transformation from anatase to rutile fully completed at 800oC. The above rutilization process was clearly recorded from XRD data, and was in good corresponding to the DSC-TGA result, in which the broad exothermic peak continued until around 800oC. Results of the sintered TiO2 ceramics (1100oC-1600oC) showed that, the densification process continued with the increase in sintering temperature and the highest geometric bulk sintered density of 3.75 g/cm3 was achieved at 1600oC. The apparent porosity significantly decreased from 18.5% to 7.0% in this temperature range, the trend of which can be also clearly observed in SEM micrographs. The hardness of the TiO2 ceramics increased with the increase in sintering temperature and the maximum hardness of 471.8±30.3 HV was obtained at 1600oC. Compression strength increased until 1500oC and the maximum value of 364.1±10.7 MPa was achieved; after which a gradual decrease was observed. While sintering at ambient atmosphere in the temperature range of 1100oC-1600oC helped to improve the densification, the grain size also increased. As a result, though the sintered density at 1600oC was the highest, large and irregular-shaped grains formed at this temperature would lead to the decrease in the compression strength.
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Date Issued
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2006
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Identifier
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CFE0001432, ucf:47036
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0001432
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Title
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SYNTHESIS, CHARACTERIZATION, AND EVALUATION OF NEW REACTIVE TWO-PHOTON ABSORBING DYES FOR TWO-PHOTON EXCITED FLUORESCENCE IMAGING APPLICATIONS.
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Creator
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Hales, Katherine, Belfield, Kevin, University of Central Florida
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Abstract / Description
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Recent, cooperative advances in chemistry, computing, optics, and microelectronics have resulted in extraordinary developments in the biological sciences, resulting in the emergence of a novel area termed ¡¥biophotonics¡¦. The interdisciplinary nature of biophotonics cuts across virtually all disciplines, extending the frontiers of basic cellular, molecular, and biology research. This holds true for the development and application of the novel imaging modality utilizing...
Show moreRecent, cooperative advances in chemistry, computing, optics, and microelectronics have resulted in extraordinary developments in the biological sciences, resulting in the emergence of a novel area termed ¡¥biophotonics¡¦. The interdisciplinary nature of biophotonics cuts across virtually all disciplines, extending the frontiers of basic cellular, molecular, and biology research. This holds true for the development and application of the novel imaging modality utilizing multiphoton absorption and its extraordinary contribution to advances in bioimaging. Intimately involved in the revolution of nonlinear bioimaging has been the development of optical probes for probing biological function and activity. The focus of this dissertation is in the area of probe development, particularly à-conjugated organic probes, optimized for efficient two-photon absorption followed by upconverted fluorescence for multiphoton bioimaging. Specifically, fluorene molecules, with enhanced two-photon absorbing (2PA) properties and high photostability, were prepared and characterized. Contemporary synthetic methods were utilized to prepare target fluorene derivatives expected to be highly fluorescent and, in particular, exhibit high two-photon absorptivity, suitable for two-photon excitation (2PE) fluorescence microscopy. The flexibility afforded through synthetic manipulation for integrating hydrophilic moieties into the fluorophore architecture to enhance compatibility with aqueous systems, more native to biological samples, was attempted. Incorporation of functional groups for direct covalent attachment onto biomolecules was also pursued to prepare fluorene derivatives as efficient 2PA reactive probes. Linear and two-photon spectroscopic characterizations on these novel compounds reveal they exhibit relatively high 2PA cross-sections on the order of ~100 GM units, which is greater than typical, commonly used fluorophores utilized in multiphoton bioimaging. Extensive photostability studies of representative fluorene compounds demonstrate these derivatives are photostable under one- and two-photon excitation conditions, exhibiting photodecomposition quantum yields on the order of 10-5. Additionally, preliminary cytotoxicity studies indicate these fluorene derivatives exhibit minimal cytotoxic effects on proliferating cells. Finally, their utility as high-performance, 2PA fluorescent probes in 2PE fluorescence microscopy imaging of biological samples was demonstrated in both fixed and live cells. Due to the low cytotoxicity, high photostability, efficient 2PA, and high fluorescence quantum yield, the probes were found suitable for relatively long-term, two-photon fluorescence imaging of live cells, representing a significant advance in biophotonics.
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Date Issued
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2005
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Identifier
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CFE0000685, ucf:46487
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0000685
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Title
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DESIGN AND SYNTHESIS OF CLOCKLESS PIPELINES BASED ON SELF-RESETTING STAGE LOGIC.
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Creator
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Alsharqawi, Abdelhalim, Ejnioui, Abdel, University of Central Florida
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Abstract / Description
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For decades, digital design has been primarily dominated by clocked circuits. With larger scales of integration made possible by improved semiconductor manufacturing techniques, relying on a clock signal to orchestrate logic operations across an entire chip became increasingly difficult. Motivated by this problem, designers are currently considering circuits which can operate without a clock. However, the wide acceptance of these circuits by the digital design community requires two...
Show moreFor decades, digital design has been primarily dominated by clocked circuits. With larger scales of integration made possible by improved semiconductor manufacturing techniques, relying on a clock signal to orchestrate logic operations across an entire chip became increasingly difficult. Motivated by this problem, designers are currently considering circuits which can operate without a clock. However, the wide acceptance of these circuits by the digital design community requires two ingredients: (i) a unified design methodology supported by widely available CAD tools, and (ii) a granularity of design techniques suitable for synthesizing large designs. Currently, there is no unified established design methodology to support the design and verification of these circuits. Moreover, the majority of clockless design techniques is conceived at circuit level, and is subsequently so fine-grain, that their application to large designs can have unacceptable area costs. Given these considerations, this dissertation presents a new clockless technique, called self-resetting stage logic (SRSL), in which the computation of a block is reset periodically from within the block itself. SRSL is used as a building block for three coarse-grain pipelining techniques: (i) Stage-controlled self-resetting stage logic (S-SRSL) Pipelines: In these pipelines, the control of the communication between stages is performed locally between each pair of stages. This communication is performed in a uni-directional manner in order to simplify its implementation. (ii) Pipeline-controlled self-resetting stage logic (P-SRSL) Pipelines: In these pipelines, the communication between each pair of stages in the pipeline is driven by the oscillation of the last pipeline stage. Their communication scheme is identical to the one used in S-SRSL pipelines. (iii) Delay-tolerant self-resetting stage logic (D-SRSL) Pipelines: While communication in these pipelines is local in nature in a manner similar to the one used in S-SRL pipelines, this communication is nevertheless extended in both directions. The result of this bi-directional approach is an increase in the capability of the pipeline to handle stages with random delay. Based on these pipelining techniques, a new design methodology is proposed to synthesize clockless designs. The synthesis problem consists of synthesizing an SRSL pipeline from a gate netlist with a minimum area overhead given a specified data rate. A two-phase heuristic algorithm is proposed to solve this problem. The goal of the algorithm is to pipeline a given datapath by minimizing the area occupied by inter-stage latches without violating any timing constraints. Experiments with this synthesis algorithm show that while P-SRSL pipelines can reach high throughputs in shallow pipelines, D-SRSL pipelines can achieve comparable throughputs in deeper pipelines.
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Date Issued
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2005
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Identifier
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CFE0000779, ucf:46590
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0000779
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Title
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Pooling correlation matrices corrected for selection bias: Implications for meta-analysis.
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Creator
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Matthews, Kenneth, Sivo, Stephen, Bai, Haiyan, Hahs-Vaughn, Debbie, Butler, Malcolm, University of Central Florida
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Abstract / Description
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Selection effects systematically attenuate correlations and must be considered when performing meta-analyses. No research domain is immune to selection effects, evident whenever self-selection or attrition take place. In educational research, selection effects are unavoidable in studies of postsecondary admissions, placement testing, or teacher selection. While methods to correct for selection bias are well documented for univariate meta-analyses, they have gone unexamined in multivariate...
Show moreSelection effects systematically attenuate correlations and must be considered when performing meta-analyses. No research domain is immune to selection effects, evident whenever self-selection or attrition take place. In educational research, selection effects are unavoidable in studies of postsecondary admissions, placement testing, or teacher selection. While methods to correct for selection bias are well documented for univariate meta-analyses, they have gone unexamined in multivariate meta-analyses, which synthesize more than one correlation from each study (i.e., a correlation matrix). Multivariate meta-analyses of correlations provide opportunities to explore complex relationships and correcting for selection effects improves the summary effect estimates. I used Monte Carlo simulations to test two methods of correcting selection effects and evaluate a method for pooling the corrected matrices. First, I examined the performance of Thorndike's corrections (for both explicit and incidental selection) and Lawley's multivariate correction for selection on correlation matrices when explicit selection takes place on a single variable. Simulation conditions included a wide range of selection ratios, samples sizes, and population correlations. The results indicated that univariate and multivariate correction methods perform equivalently. I provide practical guidelines for choosing between the two methods. In a second Monte Carlo simulation, I examined the confidence interval coverage rates of a Robust Variance Estimation (RVE) procedure when it is used to pool correlation matrices corrected for selection effects under a random-effects model. The RVE procedure empirically estimates the standard errors of the corrected correlations and has the advantage of having no distributional assumptions. Simulation conditions included tau-squared ratio, within-study sample size, number of studies, and selection ratio. The results were mixed, with RVE performing well under higher selection ratios and larger unrestricted sample sizes. RVE performed consistently across values of tau-squared. I recommend applications of the results, especially for educational research, and opportunities for future research.
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Date Issued
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2019
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Identifier
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CFE0007680, ucf:52483
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0007680
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Title
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Barriers to Adoption of Wellness Programs: A Worked Example of an Augmented Best-Fit Framework Synthesis.
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Creator
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Oliver, Dalton, Fisher, Thomas, Boote, David, Valdes, Anna, Swan, Bonnie, University of Central Florida
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Abstract / Description
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Background: Qualitative syntheses have the potential to offer a great deal of insight into complex problems of practice. However, their methods often appear unclear and warrant ongoing scrutiny by the research community. Aim: This study introduces a novel combination of methods for synthesizing qualitative literature and explores the utility of these methods through a worked example of a real-world problem of practice. Methods: Qualitative studies that investigated barriers to adoption of...
Show moreBackground: Qualitative syntheses have the potential to offer a great deal of insight into complex problems of practice. However, their methods often appear unclear and warrant ongoing scrutiny by the research community. Aim: This study introduces a novel combination of methods for synthesizing qualitative literature and explores the utility of these methods through a worked example of a real-world problem of practice. Methods: Qualitative studies that investigated barriers to adoption of wellness programs through the perspectives of key informants were systematically collected for synthesis. Key informants were identified as decision makers at small- to medium-sized businesses. The primary method used in this study was the Best-Fit Framework Synthesis (BFS). The BFS was augmented with Alignment Scores, CERQual Analysis, and a novel Saturation of Inquisition Test. Dedoose software was used to support data analysis. Results: The systematic search returned 4 studies that met the inclusion criteria. Diffusion Theory was systematically selected to develop a framework for analyzing qualitative findings. The synthesis generated four analytical themes and led to the development of a contextually rich conceptual framework. Analytical themes deeply informed the research questions while the framework offered a broader view of the overall problem. CERQual Analysis provided an added dimension of ranking amongst findings based on their level of confidence. The Saturation of Inquisition Test identified gaps in current research and validated decisions made during the synthesis. Alignment Scores identified specific points of misalignment and supported decision-making during the synthesis. Conclusion: The augmented BFS was a valuable method for synthesizing qualitative findings in a manner that informs practitioners and builds on relevant theory. The additional methods integrated seamlessly with the original BFS while enhancing transparency, reliability, and practical value of the synthesis. Further replication and critical evaluation of the overall methodology and its individual components is warranted.
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Date Issued
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2017
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Identifier
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CFE0006632, ucf:51293
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0006632
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Title
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Verification and Automated Synthesis of Memristor Crossbars.
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Creator
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Pourtabatabaie, Arya, Jha, Sumit Kumar, Chatterjee, Mainak, Pattanaik, Sumanta, University of Central Florida
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Abstract / Description
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The Memristor is a newly synthesized circuit element correlating differences in electrical charge and magnetic flux, which effectively acts as a nonlinear resistor with memory. The small size of this element and its potential for passive state preservation has opened great opportunities for data-level parallel computation, since the functions of memory and processing can be realized on the same physical device.In this research we present an in-depth study of memristor crossbars for...
Show moreThe Memristor is a newly synthesized circuit element correlating differences in electrical charge and magnetic flux, which effectively acts as a nonlinear resistor with memory. The small size of this element and its potential for passive state preservation has opened great opportunities for data-level parallel computation, since the functions of memory and processing can be realized on the same physical device.In this research we present an in-depth study of memristor crossbars for combinational and sequential logic. We outline the structure of formulas which they are able to produce and henceforth the inherent powers and limitations of Memristive Crossbar Computing.As an improvement on previous methods of automated crossbar synthesis, a method for symbolically verifying crossbars is proposed, proven and analysed.
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Date Issued
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2016
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Identifier
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CFE0006840, ucf:51765
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0006840
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Title
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The development of motuporamine derivatives and an investigation into their biological properties.
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Creator
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Skruber, Kristen, Phanstiel, Otto, Teter, Kenneth, Vonkalm, Laurence, University of Central Florida
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Abstract / Description
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This project investigates the synthesis of a class of compounds derived from a marine-based natural product and probes how iterative changes to its structure affect its derivatives' biological efficacy. The compound class of interest are the motuporamines which were isolated from the sea sponge Xestospongia exigua collected off the coast of Motupore island in Papua, New Guinea. The compounds for this project are predicated upon dihydromotuporamine C (Motu33), the compound that has been shown...
Show moreThis project investigates the synthesis of a class of compounds derived from a marine-based natural product and probes how iterative changes to its structure affect its derivatives' biological efficacy. The compound class of interest are the motuporamines which were isolated from the sea sponge Xestospongia exigua collected off the coast of Motupore island in Papua, New Guinea. The compounds for this project are predicated upon dihydromotuporamine C (Motu33), the compound that has been shown to be both cytotoxic to MDA-MB231 breast carcinoma cells and has antimetastatic efficacy. The motuporamine scaffold contains a large fifteen-membered saturated macrocycle and an appended polyamine component. A series of Motu33 derivatives were synthesized and evaluated for their ability to target the polyamine transport system as well as inhibit cell migration of human pancreatic cancer cells in vitro. By altering the polyamine component of the system we attempted to build smart antimetastatic compounds which target the upregulated polyamine transport system of human pancreatic cancers and block their migration.
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Date Issued
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2016
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Identifier
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CFE0006505, ucf:51390
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0006505
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Title
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Combustion Synthesis and Characterization of Porous NiTi Intermetallic For Structural Application.
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Creator
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Vanterpool, Jessica, Ilegbusi, Olusegun, Gou, Jihua, Nicholson, David, University of Central Florida
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Abstract / Description
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This thesis describes experimental investigation of thermal and combustion phenomena as well as structure for self- propagating combustion synthesis of porous Ni - Ti intermetallic aimed for structural biomedical application. The control parameters for the porosity distribution have been investigated experimentally through varying the preheat temperature, initial porosity, initial elemental particle size, and applied pressure during the fabrication process. Ni and Ti elemental powders are...
Show moreThis thesis describes experimental investigation of thermal and combustion phenomena as well as structure for self- propagating combustion synthesis of porous Ni - Ti intermetallic aimed for structural biomedical application. The control parameters for the porosity distribution have been investigated experimentally through varying the preheat temperature, initial porosity, initial elemental particle size, and applied pressure during the fabrication process. Ni and Ti elemental powders are mixed using a 1:1 ratio. The mixture is compressed using several different compression forces to produce cylindrical samples of 1.1 cm diameter and 2-3cm length, with initial porosity ranging from 30% to 40%. The samples are preheated to various initial temperatures and ignited from the top surface such that the flame propagates axially downwards. The combustion reaction is recorded with a motion camera. An infrared sensor is used to record the temperature profile during the combustion process. The samples are then cut using a diamond saw in both longitudinal and transverse directions. Image analysis software is then used to analyze the porosity distribution in each sample.
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Date Issued
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2013
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Identifier
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CFE0004768, ucf:49803
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0004768
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Title
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Synthetic Design and Characterization of Polycyclic Aromatic Compounds in Molecular and Extended System.
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Creator
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Pour, Gavin, Belfield, Kevin, Frazer, Andrew, Elsheimer, Seth, University of Central Florida
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Abstract / Description
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The work presented herein focuses on the synthesis and characterization of polycyclic aromatic compounds for a wide variety of toxicological, analytical, and electronic applications. First, the modular synthesis of 12 dibenzo- and naphtho- fluoranthene polycyclic aromatic hydrocarbons (PAHs) via a Pd-catalyzed five-membered ring closing procedure is discussed. By understanding the various modes through which the Pd migrates during transformation, structural rearrangements were bypassed,...
Show moreThe work presented herein focuses on the synthesis and characterization of polycyclic aromatic compounds for a wide variety of toxicological, analytical, and electronic applications. First, the modular synthesis of 12 dibenzo- and naphtho- fluoranthene polycyclic aromatic hydrocarbons (PAHs) via a Pd-catalyzed five-membered ring closing procedure is discussed. By understanding the various modes through which the Pd migrates during transformation, structural rearrangements were bypassed, obtaining regioselectivity through various redesigns in the synthetic route. Each compound in the serious was rigorously characterized via 1D/2D NMR, absorption and emission spectroscopy as well as cyclic voltammetry, which shows vast differences due to small structural changes between these constitutional isomers. Next, a series of polyphenylated organic ligands for zirconium metal organic frameworks is presented as materials for post-synthetic Scholl cyclodehydrogenation. Lastly, a series of organic linkers featuring covalently anchored redox-active pendants is explored for tuneable redox activity in Zr-based metal-organic frameworks. Thin-films were grown onto fluorine-doped tin-oxide glass electrodes and analyzed by cyclic voltammetry. This is the first reported pre-synthetic incorporation of covalently-bound ferrocenyl pendants into such a system. By attenuating the proportions of redox active and inactive links the oxidative peak currents could be tuned. This body of work represents a contribution toward the practical design and synthesis of polycyclic aromatic for a wide variety of analytical and electrochemical applications.
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Date Issued
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2019
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Identifier
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CFE0007512, ucf:52647
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0007512
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Title
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Techniques for automated parameter estimation in computational models of probabilistic systems.
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Creator
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Hussain, Faraz, Jha, Sumit, Leavens, Gary, Turgut, Damla, Uddin, Nizam, University of Central Florida
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Abstract / Description
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The main contribution of this dissertation is the design of two new algorithms for automatically synthesizing values of numerical parameters of computational models of complexstochastic systems such that the resultant model meets user-specified behavioral specifications.These algorithms are designed to operate on probabilistic systems (-) systems that, in general,behave differently under identical conditions. The algorithms work using an approach thatcombines formal verification and...
Show moreThe main contribution of this dissertation is the design of two new algorithms for automatically synthesizing values of numerical parameters of computational models of complexstochastic systems such that the resultant model meets user-specified behavioral specifications.These algorithms are designed to operate on probabilistic systems (-) systems that, in general,behave differently under identical conditions. The algorithms work using an approach thatcombines formal verification and mathematical optimization to explore a model's parameterspace.The problem of determining whether a model instantiated with a given set of parametervalues satisfies the desired specification is first defined using formal verification terminology,and then reformulated in terms of statistical hypothesis testing. Parameter space explorationinvolves determining the outcome of the hypothesis testing query for each parameter pointand is guided using simulated annealing. The first algorithm uses the sequential probabilityratio test (SPRT) to solve the hypothesis testing problems, whereas the second algorithmuses an approach based on Bayesian statistical model checking (BSMC).The SPRT-based parameter synthesis algorithm was used to validate that a given model ofglucose-insulin metabolism has the capability of representing diabetic behavior by synthesizingvalues of three parameters that ensure that the glucose-insulin subsystem spends at least 20minutes in a diabetic scenario. The BSMC-based algorithm was used to discover the valuesof parameters in a physiological model of the acute inflammatory response that guarantee aset of desired clinical outcomes.These two applications demonstrate how our algorithms use formal verification, statisticalhypothesis testing and mathematical optimization to automatically synthesize parameters ofcomplex probabilistic models in order to meet user-specified behavioral properties
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Date Issued
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2016
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Identifier
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CFE0006117, ucf:51200
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0006117
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Title
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MODELING SCENES AND HUMAN ACTIVITIES IN VIDEOS.
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Creator
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Basharat, Arslan, Shah, Mubarak, University of Central Florida
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Abstract / Description
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In this dissertation, we address the problem of understanding human activities in videos by developing a two-pronged approach: coarse level modeling of scene activities and fine level modeling of individual activities. At the coarse level, where the resolution of the video is low, we rely on person tracks. At the fine level, richer features are available to identify different parts of the human body, therefore we rely on the body joint tracks. There are three main goals of this dissertation: ...
Show moreIn this dissertation, we address the problem of understanding human activities in videos by developing a two-pronged approach: coarse level modeling of scene activities and fine level modeling of individual activities. At the coarse level, where the resolution of the video is low, we rely on person tracks. At the fine level, richer features are available to identify different parts of the human body, therefore we rely on the body joint tracks. There are three main goals of this dissertation: (1) identify unusual activities at the coarse level, (2) recognize different activities at the fine level, and (3) predict the behavior for synthesizing and tracking activities at the fine level. The first goal is addressed by modeling activities at the coarse level through two novel and complementing approaches. The first approach learns the behavior of individuals by capturing the patterns of motion and size of objects in a compact model. Probability density function (pdf) at each pixel is modeled as a multivariate Gaussian Mixture Model (GMM), which is learnt using unsupervised expectation maximization (EM). In contrast, the second approach learns the interaction of object pairs concurrently present in the scene. This can be useful in detecting more complex activities than those modeled by the first approach. We use a 14-dimensional Kernel Density Estimation (KDE) that captures motion and size of concurrently tracked objects. The proposed models have been successfully used to automatically detect activities like unusual person drop-off and pickup, jaywalking, etc. The second and third goals of modeling human activities at the fine level are addressed by employing concepts from theory of chaos and non-linear dynamical systems. We show that the proposed model is useful for recognition and prediction of the underlying dynamics of human activities. We treat the trajectories of human body joints as the observed time series generated from an underlying dynamical system. The observed data is used to reconstruct a phase (or state) space of appropriate dimension by employing the delay-embedding technique. This transformation is performed without assuming an exact model of the underlying dynamics and provides a characteristic representation that will prove to be vital for recognition and prediction tasks. For recognition, properties of phase space are captured in terms of dynamical and metric invariants, which include the Lyapunov exponent, correlation integral, and correlation dimension. A composite feature vector containing these invariants represents the action and will be used for classification. For prediction, kernel regression is used in the phase space to compute predictions with a specified initial condition. This approach has the advantage of modeling dynamics without making any assumptions about the exact form (polynomial, radial basis, etc.) of the mapping function. We demonstrate the utility of these predictions for human activity synthesis and tracking.
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Date Issued
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2009
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Identifier
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CFE0002897, ucf:48042
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0002897
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Title
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BACTERIA THAT RESIST CENTRIFUGAL FORCE.
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Creator
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Kessler, Nickolas, Moore, Sean, University of Central Florida
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Abstract / Description
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Our lab discovered that approximately 1 in 10,000 Escherichia coli cells in stationary phase remain in suspension after a high g-force centrifuge event. To establish the mechanism behind this curious phenotype, multiple mutant strains of E. coli were independently evolved such that the majority of their populations resisted migration when exposed to high centrifugal forces. Genomic DNA sequencing of the mutants' revealed unique, isolated mutations in genes involved in capsule synthesis and...
Show moreOur lab discovered that approximately 1 in 10,000 Escherichia coli cells in stationary phase remain in suspension after a high g-force centrifuge event. To establish the mechanism behind this curious phenotype, multiple mutant strains of E. coli were independently evolved such that the majority of their populations resisted migration when exposed to high centrifugal forces. Genomic DNA sequencing of the mutants' revealed unique, isolated mutations in genes involved in capsule synthesis and exopolysaccharide (EPS) production. Each mutant exhibits a novel mechanism that allows them to remain in suspension. The mutants were further characterized by determining their growth rates, strengths of resistance to various centrifugal forces, the phenotype's dependence on a carbon source, and timing of the phenotype's presentation. The results revealed: comparable mutant generation times to the wild-type strain, variable resistance to centrifugal force, phenotype dependence on carbon source, and phenotype presentation during early stationary phase. To interrogate the mechanism by which these cells stay in suspension the production of EPS was quantified, and gene knock-outs were performed. Quantification of the EPS revealed approximately a seventeen-fold increase in EPS in the mutants' compared to the wild-type strain. Gene knock-outs revealed the EPS produced can be attached to the outer-membrane or freely secreted into the media by different mechanisms. In addition, this mechanism was further confirmed to be responsible for the centrifuge resistant trait by attaching extracted EPS to polystyrene microspheres. Experimental results show that mutant extracted EPS treated beads caused increased bead retention in suspension compared to wild-type EPS treated beads. These results reveal that E. coli is using a novel mechanism to adapt to a new environmental factor introduced to remove the bacteria. With the discovery of this mechanism and the transferability to inorganic objects industrial applications are now envisioned where particle sedimentation is controllable and mixtures remain homogenized by attaching optically transparent biomolecules.
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Date Issued
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2018
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Identifier
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CFH2000332, ucf:45800
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFH2000332
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Title
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ARC-DISCHARGE IN SOLUTION: A NOVEL SYNTHESIS METHOD FOR CARBON NANOTUBES AND IN SITU DECORATION OF CARBON NANOTUBES WITH NANOPARTICLES.
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Creator
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Bera, Debasis, Seal, Sudipta, University of Central Florida
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Abstract / Description
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Nanotechnology has reached the status of the 21st century's leading science and technology based on fundamental and applied research during the last two decades. An important feature of nanotechnology is to bridge the crucial dimensional gap between the atomic and molecular fundamental sciences and microstructural scale of engineering. Accordingly, it is very important to have an in-depth understanding of the synthesis of nanomaterials for the use of state-of-the-art high technological...
Show moreNanotechnology has reached the status of the 21st century's leading science and technology based on fundamental and applied research during the last two decades. An important feature of nanotechnology is to bridge the crucial dimensional gap between the atomic and molecular fundamental sciences and microstructural scale of engineering. Accordingly, it is very important to have an in-depth understanding of the synthesis of nanomaterials for the use of state-of-the-art high technological devices with enhanced properties. Recently, the 'bottom-up' approach for the fabrication of nanomaterials has received a great deal of attention for its simplicity and cost effectiveness. Tailoring the various parameters during synthesis of selected nanoparticles can be used to fabricate technologically important components. During the last decade, carbon nanotubes (CNTs) have been envisioned for a host of different new applications. Although carbon nanotubes can be synthesized using a variety of techniques, large-scale synthesis is still a great challenge to the researchers. Three methods are commonly used for commercial and bulk productions of carbon nanotubes: arc-discharge, chemical vapor deposition and laser ablation. However, low-cost, large-scale production of high-quality carbon nanotubes is yet to be reported. One of the objectives of the present research is to develop a simplified synthesis method for the production of large-scale, low-cost carbon nanotubes with functionality. Herein, a unique, simple, inexpensive and one-step synthesis route of CNTs and CNTs decorated with nanoparticles is reported. The method is simple arc-discharge in solution (ADS). For this new method, a full-fledged optoelectronically controlled instrumen is reported here to achieve high efficiency and continuous bulk production of CNTs. In this system, a constant gap between the two electrodes is maintained using a photosensor which allows a continuous synthesis of the carbon nanostructures. The system operates in a feedback loop consisting of an electrode-gap detector and an analogue electronic unit, as controller. This computerized feed system was also used in single process step to produce in situ-decorated CNTs with a variety of industrially important nanoparticles. To name a few, we have successfully synthesized CNTs decorated with 3-4 nm ceria, silica and palladium nanoparticles for many industrially relevant applications. This process can be extended to synthesize decorated CNTs with other oxide and metallic nanoparticles. Sixty experimental runs were carried out for parametric analysis varying process parameters including voltage, current and precursors. The amount of yield with time, rate of erosion of the anode, and rate of deposition of carbonaceous materials on the cathode electrode were investigated. Normalized kinetic parameters were evaluated for different amperes from the sets of runs. The production rate of pristine CNT at 75 A is as high as 5.89 ± 0.28 g.min-1. In this study, major emphasis was given on the characterizations of CNTs with and without nanoparticles using various techniques for surface and bulk analysis of the nanostructures. The nanostructures were characterized using transmission electron microscopy, high resolution transmission electron microscopy, scanning transmission electron microscopy, energy dispersive spectroscopy and scanning electron microscopy, x-ray photo electron spectroscopy, x-ray diffraction studies, and surface area analysis. Electron microscopy investigations show that the CNTs, collected from the water and solutions, are highly pure except the presence of some amorphous carbon. Thermogravimetric analysis and chemical oxidation data of CNTs show the good agreement with electron microscopy analysis. The surface area analysis depicts very high surface area. For pristine multi-walled carbon nanotubes, the BET surface area is approximately 80 m2.g-1. X-ray diffraction studies on carbon nanotubes shows that the products are clean. Nano-sized palladium decorated carbon nanotubes are supposed to be very efficient for hydrogen storage. The synthesis for in-situ decoration of palladium nanoparticles on carbon nanotubes using the arc discharge in solution process has been extensively carried out for possible hydrogen storage applications and electronic device fabrication. Palladium nanoparticles were found to form during the reduction of palladium tetra-chloro-square planar complex. The formation of such a complex was investigated using ultraviolet-visible spectroscopic method. Pd-nanoparticles were simultaneously decorated on carbon nanotubes during the rolling of graphene sheets in the arc-discharge process. Zero-loss energy filtered transmission electron microscopy and scanning transmission electron microscopy confirm the presence of 3 nm palladium nanoparticles. The deconvoluted X-ray photoelectron spectroscopy envelope shows the presence of palladium. Surface area measurements using BET method show a surface area of 28 m2.g-1. The discrepancy with pristine CNTs can be explained considering the density of palladium (12023 kg.m-3). Energy dispersive spectroscopy suggests no functionalization of chlorine to the sidewall of carbon nanotubes. The presence of dislodged graphene sheets with wavy morphology as observed with high-resolution transmission electron microscopy supports the formation of CNTs through the 'scroll mechanism'.
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Date Issued
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2005
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Identifier
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CFE0000450, ucf:46388
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0000450
Pages