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Hung, Hiu-ling, and 洪曉翎. "Characterization of mitochondrial morphology and dynamics in neurodegeneration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B50126362.
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Yuan, Yue. "Morphology-driven superhydrophobic polystyrene webs: fabrication and characterization." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32893.
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Master of ScienceDepartment of Apparel, Textiles, and Interior Design
Jooyoun Kim
Seong-O Choi
Superhydrophobicity (water contact angle, WCA >150˚) can be achieved by introducing surface roughness and decreasing surface energy. Polystyrene (PS) electrospun web can be used as an excellent substrate for superhydrophobic surface due to its low surface energy (~33 mN/m) and processibility to form various roughness. As the Cassie-Baxter model explains, the presence of roughness amplifies anti-wettability of materials whose surface energy is low (hydrophobic, WCA >90˚). This study aims to fabricate superhydrophobic PS nonwoven webs by electrospinning process and vapor deposition of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFDTS) and to investigate the influence of fiber morphology and surface energy on wettability. To this end, PS webs with various fiber morphologies were electrospun under different polymer concentrations and solvent mixtures. PS substrates were treated by air plasma to attach –OH groups before the vapor deposition of PFDTS. Air plasma treatment itself increased the surface energy of PS; however, with PFDTS coating, the surface energy was decreased. The wettability was characterized by WCA and sliding angle measurement. WCAs on the electrospun webs were greater than that of flat PS film (WCA=95˚) due to the increased roughness of the web. The web with beads or grooved fibers achieved superhydrophobicity (WCA>150˚). PFDTS deposition lowered the surface energy of PS surface to about 15.8 mN/m. PS web with PFDTS deposition presented high water contact angle up to 169˚ and low sliding angle about 3˚. Also it was attempted to characterize the interfacial area between water and a solid surface on irregular fibrous webs. The fraction of solid surface area wet by the liquid (solid fraction) was observed by staining the rough electrospun web with a hydrophobic fluorescent dye, coumarin. The actual solid fraction corresponded fairly well with the theoretical solid fraction calculated by the Cassie-Baxter equation, demonstrating that the treated superhydrophobic surface follows the Cassie-Baxter wetting state.
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Laine, Guy C. "CHARACTERIZATION OF AND CONTROLLING MORPHOLOGY OF ULTRA-THIN NANOCOMPOSITES." UKnowledge, 2013. http://uknowledge.uky.edu/cme_etds/23.
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Ultrathin film nanocomposites are becoming increasingly important for specialized performance of commercial coatings. Critical challenges for ultrathin film nanocomposites include their synthesis and characterization as well as their performance properties, including surface roughness, optical properties (haze, refractive index as examples), and mechanical properties. The objective of this work is to control the surface roughness of ultrathin film nanocomposites by changing the average particle size and the particle volume fraction (loading) of monomodal particle size distributions. This work evaluated one-layer and two-layer films for their surface properties. Monodispersed colloidal silica nanoparticles were incorporated into an acrylate-based monomer system as the model system. Ultrathin nanocomposites were prepared with three different size colloidal silica (13, 45, and 120 nm nominal diameters) at three different particle loadings (20, 40, and 50 vol. % inorganic solids). Silica particles were characterized using DLS and TEM. AFM was used to measure the root mean square roughness (Rq), ΔZ, and location-to-location uniformity of one-layer and two-layer nanocomposite coatings. Developing an understanding about the properties affected by the type and amount of particles used in a nanocomposite can be used as a tool with nanocharacterization techniques to quickly modify and synthesize desired ultrathin film coatings.
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Wadley, Maurice L. "Synthesis and Morphology Characterization of Polydimethylsiloxane-Containing Block Copolymers." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1323132195.
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Musseau, Constance. "Towards the identification and characterization of new regulators of fruit tissue morphology." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0355.
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La taille du fruit et la morphologie des tissus du fruit sont des caractères clés définissant la qualité finale du fruit. Parmi la grande diversité de fruits observée dans la nature, la domestication et la sélection ont entrainé d’importantes modifications de la taille et de la morphologie des tissus du fruit. Jusqu'à présent, seuls quelques régulateurs génétiques ont été identifiés, et les mécanismes cellulaires et moléculaires par lesquels la morphologie des tissus du fruit est définie restent imprécis. Dans ce contexte, l'objectif de ma thèse est d'identifier et de caractériser de nouveaux régulateurs impliqués dans la morphologie des tissus du fruit. Pour cela, j'ai utilisé une collection de mutants EMS de tomate comme source de diversité génétique et phénotypique et j'ai sélectionné deux mutants présentant des tendances opposées et extrêmes d'épaisseur du péricarpe. Grace à une stratégie de cartographie par séquençage, j’ai identifié une région génétique du chromosome 10, associée au phénotype péricarpe épais. J'ai également étudié le rôle de la Guanylate Binding Protein (GBP) à l’origine du phénotype péricarpe fin chez la tomate. La GBP est une grosse GTP binding protein qui n’a jamais été caractérisée chez les plantes. Afin d'approfondir l’étude de cette protéine, j'ai étudié en parallèle son rôle dans les modèles tomate et Arabidopsis" thaliana. J'ai démontré que les deux protéines homologues sont localisées dans le noyau. La mutation de la GBP chez la tomate induit de fortes altérations de la division et de l'expansion cellulaire à l'intérieur du péricarpe ainsi qu'une altération de la croissance des racines latérales chez la tomate et Arabidopsis, une caractéristique classiquement retrouvée chez les mutants altérés dans la mitose. Cette étude suggère que le GBP joue un rôle dans le contrôle précis des divisions cellulaires dans le péricarpe de tomateFruit size and morphology are key characters defining the final fruit quality. Among the large fruit diversity observed in the nature, human domestication and selection has induced changes in fruit size and tissue morphology. Only a few genetic regulators have been identified so far, thus cellular and molecular mechanisms by which fruit tissue morphology is defined remain incomplete. In this context, the aim of my thesis is to identify and characterize new regulators of fruit tissue morphology. For this purpose, I used a collection of tomato EMS mutants as a source of genetic and phenotypic diversity. I selected two mutants presenting opposite trends of pericarp thickness. Through a mapping-by-sequencing strategy, I identified a genetic region on chromosome 10, associated with an extreme thick pericarp phenotype. I also investigated the role of the Guanylate Binding Protein (GBP) at the origin of a thin pericarp phenotype. The GBP is a large GTP binding protein that was never characterized in plants so far. In order to go deeper into its functional characterization in plants, I studied in parallel the role of the protein in tomato and Arabidopsis "thaliana" models. I showed that both homolog proteins are localized at the nucleus. Mutation of GBP in tomato induced strong alterations in cell division and cell expansion inside the pericarp and altered lateral root growth in tomato and Arabidopsis, a classical feature for mutants impaired in mitosis. This study suggests a role for the GBP in the fine control of cell division in the tomato pericarp
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Rochmis, Laura. "A Correlated LM/SEM Method for the Morphological Characterization of Gene Expression in Xenopus laevis." W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539625967.
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Bélanger, Christian. "Characterization of polymer blend morphology from patterns of reflected scattered light." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39740.
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The morphology and properties of polymer blends are closely related to processing conditions. The minor phase dimensions usually range from 0.1 to 10 $ mu$m. A skin/core morphology, with a minor phase undergoing variations in orientation and aspect ratio from the surface to the core of the material is observed in processes such as the injection molding of blends. The use of optical inspection is a potential tool to control the stability and the quality of the product on-line. In this thesis, polymer composites made from different glass fibers and glass microspheres embedded in a matrix of PS are used to simulate two-phase polymer blend morphology with a skin/core configuration. Two apparatuses have been used to characterize the morphology of the specimen by light scattering in reflection. The first had an incident light beam at 45 degrees from a normal to the surface of the sample. The second apparatus projected the laser beam incident perpendicularly on the surface of the sample and used polarized light. Distinctive reflected light scattering patterns were obtained in both cases and analyzed. In the first case, ratios of the axes of the ellipsoidal iso-intensity curves were plotted as a function of the position from the center of the light beam. The anisotropy of the iso-intensity lines is also plotted as a function of the position of the center of the beam for the second case. In both situations, information is obtained from the change of the anisotropy ratio as function of the distance from the center of the beam for depth-varying morphology samples. The skin, and the core content as well as the skin thickness effect can be isolated from the processed images. The second technique gave more information and patterns which were easier to process.A Monte Carlo program was written to simulate the propagation of photons in the samples containing a spherical morphology. The simulation is a potential tool for the analysis or two-phase systems but requires further development to be a useful tool.
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Miller, Jeri L. "Ultrasonic tissue characterization of the tongue : spectral features of tissue morphology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0022/NQ50222.pdf.
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Senn, Simon Charles. "The preparation and characterization of hollow fibre membranes for gas separation." Thesis, University of Leeds, 1988. http://etheses.whiterose.ac.uk/405/.
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A dry-jet wet-spinning process developed industrially for the preparation of hollow fibre membranes suitable for gas separation applications, has been reproduced on a laboratory scale. Polysulphone hollow fibres were spun from a variety of solvents and their gas transport properties were characterized using equipment built during the course of the research. The phase inversion process of membrane formation was studied in order that the best morphological structure could be produced. The spinning parameters were studied to establish their influence on the fibre dimensions. Further relationships were then sought between the gas transport properties and the fibre dimensions and spinning parameters. The behaviour of the membranes to both single gases and gas mixtures was studied. Both the permeation rate constants and the separation factors determined from the mixture permeation were found to be lower than the values predicted from the single gas permeation experiments. A model was developed to help understand the competitive nature of the adsorption-diffusion process and explain the differences in values recorded from the single gas and mixture studies. Experiments aimed at improving membrane performance were based on modification of the already established polysulphone hollow fibre. Modification of the selective surface layer of the hollow fibre membranes was considered to be the best approach. Coating of the fibres, other than to repair damage to the skin layer, was found to result in too large a decrease in permeability. Sulphonation of the surface layer was achieved using sulphur trioxide, although little improvement in the membrane performance was recorded. The sulphonation experiment results were, however, sufficiently encouraging to recommend future work.
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Mertens, Robert G. "Characterization, Morphology, Oxidation, and Recession of Silicon Nanowires Grown by Electroless Process." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5437.
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This dissertation presents heretofore undiscovered properties of Silicon Nanowires (SiNWs) grown by electroless process and presents mathematical solutions to the special problems of the oxidation and diffusion of dopants for SiNWs. Also presented here is a mathematical description of morphology of oxidized SiNWs. This dissertation is comprised of several discussions relating to SiNWs growth, oxidation, morphology and doping. In here is presented work derived from a long-term study of SiNWs. Several important aspects of SiNWs were investigated and the results published in journals and conference papers. The recession of SiNWs was heretofore unreported by other research groups. In our investigations, this began as a question, “How far into the substrate does the etching process go when this method is used to make SiNWs?” Our investigations showed that recession did take place, was controllable and that a number of variables were responsible. The growth mechanism of SiNWs grown by electroless process is discussed at length. The relation of exposed area to volume of solution is shown, derived from experimentation. A relation of Silver used to Si removed is presented, derived from experimentation. The agglomeration of SiNWs grown by the electroless process is presented. The oxidation of SiNWs is a subject of interest to many groups, although most other groups work with SiNWs grown by the VLS process, which is more difficult, time-consuming and expensive to do. The oxidation of planar Silicon (Si) is still a subject of study, even today, after many years of working with and refining our formulae, because of the changing needs of this science and industry. SiNWs oxidation formulae are more complicated than those for planar Si, partly because of their morphology and partly because of their scale. While planar Si only presents one orientation for oxidation, SiNWs present a range of orientations, usually everything between <100> and <110> (the <111> orientation is usually not presented during oxidation). This complicates the post-oxidation morphology to the extent that, subsequent to oxidation, SiNWs are more rectangular than cylindrical in shape. After etching to remove an oxidation layer from the SiNWs, the rectangular shape shifts 90[degrees] in orientation. In traditional oxidation, the Deal-Grove formulae are used, but when the oxidation must take place in very small layers, such as with nanoscale devices, the Massoud formulae have to be used. However, even with Massoud, these formulae are not as good because of the morphology. Deal-Grove and Massoud formulae are intended for use with planar Si. We present some formulae that show the change in shape of SiNWs during oxidation, due to their morphology. The diffusion of dopants in SiNWs is a subject few research groups have taken up. Most of the groups who have, use SiNWs grown by the VLS method to make measurements and report findings. In order to measure the diffusion of dopants in SiNWs, a controllable diameter is needed. There are a number of ways to measure diffusion in SiNWs, but none of the ones used so far apply well to SiNWs grown by electroless process. Usually these groups present some mathematical formulae to predict diffusion in SiNWs, but these seem to lack mathematical rigor. Diffusion is a process that is best understood using Fick's Laws, which are applied to the problem of SiNWs in this dissertation. Diffusion is a science with a long history, going back at least 150 years. There are many formulae that can be used in the most common diffusion processes, but the processes involved with the diffusion of dopants in SiNWs is more complex than the simple diffusion processes that are fairly well-understood. Diffusion doping of SiNWs is a multiphase process that is more complex, first because it is multiphase and second because the second step involves a multiplicity of diffusing elements, plus oxidation, which brings on the problems of moving boundaries. In this dissertation, we present solutions to these problems, and the two-step diffusion process for SiNWs.ID: 031001390; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Kalpathy B. Sundaram.; Title from PDF title page (viewed May 24, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 89-97).
Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
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Hailesilassie, Biruk. "Morphology Characterization of Foam Bitumen and Modeling for Low Temperature Asphalt Concrete." Doctoral thesis, KTH, Byggnadsmaterial, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-183105.
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Development of new asphalt technologies to reduce both energy consumption and CO2 production has attracted great interest in recent years. The use of foam bitumen, as one of them, is attractive due to the low investment and production cost. Formation and decay of foam bitumen is a highly dynamic temperature dependent process which makes characterization difficult. In this thesis, new experimental tools were developed and applied for characterizing the foam bitumen during the hot foaming process. One of the main goals of this study was to improve understanding and characterization of the foam bitumen formation and decay. X-ray radiography was used to study the formation and decay of foam bitumen in 2D representation. The results demonstrate that the morphology of bubble formation depends on the types of bitumen used. Moreover, theoretical investigation based on the 3D X-ray computed tomography scan dataset of bubble merging showed that the disjoining pressure increased as the gap between the bubbles in the surface layer (foam film) decreased with time and finally was ruptured. Examining the foam bitumen stream right at the nozzle revealed that foam bitumen at a very early stage contains fragmented pieces of irregular size rather resembling a liquid than foam. The result from thermogravimetric analysis demonstrated that residual water content depends on the initial water content, and was found to be between 38 wt% and 48 wt% of the initial water content of 4 wt% to 6 wt%. Moreover the influence of viscosity and surface tension on bubble shape and rise velocity of the bubbles using level-set method was implemented in finite element method. The modeling results were compared with bubble shape correlation map from literature. The results indicated that the bubble shapes are more dependent on the surface tension parameters than to the viscosity of the bitumen, whereas the bitumen viscosity is dominant for bubble rising velocity.QC 20160303
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KUTZ, SUSAN MARIE. "ISOLATION AND CHARACTERIZATION OF A HELICALLY TWISTED BACTERIUM RESEMBLING SELIBERIA." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184075.
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A seliberia-like bacterium (SLO), isolated from reverse osmosis membranes was characterized by morphological, physiological and DNA studies. The helically twisted cells of this organism were often observed in star-shaped clusters. Depending on nutritional conditions, cells ranged from 0.5 to 21 um in length and possessed prosthecae. Small motile cells were produced by asymmetric fission or by a budding process. Ovoid "generative" cells were observed in mixed culture conditions or when the pure culture isolate was grown in the presence of humic acid. The SLO oxidatively utilized glucose, maltose, xylose, cellobiose, and several amino acids as sole carbon and energy sources. The organism is a strict aerobe and does not anaerobically respire. The moles percent guanine plus cytosine (mol% G + C) of the SLO DNA was 38% as compared with 63-67% for Seliberia stellata. Although the cellular morphology and physiology of the SLO closely resembles that of S. stellata, the SLO is considered to be a new species of Seliberia based on the presence of prosthecae and the mol% G + C.
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Lane, Ozma Redd. "Synthesis and Characterization of Sulfonated Poly(arylene ether sulfone)s for Membrane Separations." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/78431.
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Sulfonated poly(arylene ether sulfone)s are a class of engineering thermoplastics well-known for their mechanical properties and chemical/oxidative stability. The research in this dissertation focuses on modifying the structure of sulfonated poly(arylene ether sulfone)s to improve membrane performance. Blends of a 20% disulfonated poly(arylene ether sulfone) (BPS20) with poly(ethylene glycol) (PEG) were investigated with the objective of promoting water flux across a reverse osmosis membrane.
It was considered desirable to investigate poly(arylene ether sulfone)s with a hydroquinone unit that could be controllably post-sulfonated without degradation, providing a polymer with controlled sulfonation through controlling hydroquinone content. It also avoided the disadvantages noted previously in polymers with post-sulfonated biphenol units. Initial experiments focused on determining sulfonation conditions to confirm quantitative sulfonation of the hydroquinone without side reactions or degradation. A polymer with 29 mole % hydroquinone-containing units was used to study the rate of sulfonation. Successful post-sulfonation was confirmed and reaction conditions were applied to a series of polymers with varying hydroquinone comonomer contents. These polymers were sulfonated, characterized and evaluated for transport properties. Of interest was the high sodium rejection in the presence of
calcium, which in the directly copolymerized disulfonated materials is compromised. The post-sulfonated poly(arylene ether sulfone)s showed no compromise in sodium rejection in a mixed-feed of sodium chloride and calcium chloride.
In the membrane electrolysis of water, Nafion's high permeability to hydrogen, particularly above about 80 C, results in back-diffusion of hydrogen across the membrane. This reduces efficiency, product purity, and long-term electrode stability. Hydrophilic-hydrophobic multiblock copolymers based on disulfonated and non-sulfonated poly(arylene ether sulfone) oligomers feature a lower gas permeability. Various multiblock compositions and casting conditions were investigated and transport properties were characterized. A multiblock poly(arylene ether sulfone) showed a significant improvement in performance over Nafion at 95°C.
Multiblock hydrophilic-hydrophobic poly(arylene ether sulfone)s have been extensively investigated as alternatives for proton exchange membrane fuel cells. One concern with these materials is the complicated multi-step synthesis and processing of oligomers, followed by coupling to produce a multiblock copolymer. An streamlined synthetic process was successful for synthesizing membranes with comparable morphologies and performance to a multiblock synthesized via the traditional method.Ph. D.
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Fehri, Amin. "Image Characterization by Morphological Hierarchical Representations." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM063/document.
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Cette thèse porte sur l'extraction de descripteurs hiérarchiques et multi-échelles d'images, en vue de leur interprétation, caractérisation et segmentation. Elle se décompose en deux parties.La première partie expose des éléments théoriques et méthodologiques sur l'obtention de classifications hiérarchiques des nœuds d'un graphe valué aux arêtes. Ces méthodes sont ensuite appliquées à des graphes représentant des images pour obtenir différentes méthodes de segmentation hiérarchique d'images. De plus, nous introduisons différentes façons de combiner des segmentations hiérarchiques. Nous proposons enfin une méthodologie pour structurer et étudier l'espace des hiérarchies que nous avons construites en utilisant la distance de Gromov-Hausdorff entre elles.La seconde partie explore plusieurs applications de ces descriptions hiérarchiques d'images. Nous exposons une méthode pour apprendre à extraire de ces hiérarchies une bonne segmentation de façon automatique, étant donnés un type d'images et un score de bonne segmentation. Nous proposons également des descripteurs d'images obtenus par mesure des distances inter-hiérarchies, et exposons leur efficacité sur des données réelles et simulées. Enfin, nous étendons les potentielles applications de ces hiérarchies en introduisant une technique permettant de prendre en compte toute information spatiale a priori durant leur constructionThis thesis deals with the extraction of hierarchical and multiscale descriptors on images, in order to interpret, characterize and segment them. It breaks down into two parts.The first part outlines a theoretical and methodological approach for obtaining hierarchical clusterings of the nodes of an edge-weighted graph. In addition, we introduce different approaches to combine hierarchical segmentations. These methods are then applied to graphs representing images and derive different hierarchical segmentation techniques. Finally, we propose a methodology for structuring and studying the space of hierarchies by using the Gromov-Hausdorff distance as a metric.The second part explores several applications of these hierarchical descriptions for images. We expose a method to learn how to automatically extract a segmentation of an image, given a type of images and a score of evaluation for a segmentation. We also propose image descriptors obtained by measuring inter-hierarchical distances, and expose their efficiency on real and simulated data. Finally, we extend the potential applications of these hierarchies by introducing a technique to take into account any spatial prior information during their construction
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Demir, Özlem. "Functional Characterization of Microtubule Associated Proteins in ES Cell Division and Neuronal Differentiation." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-163103.
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Microtubules are tubular polymers that are involved in a variety of cellular processes such as cell movement, mitosis and intracellular transport. The dynamic behavior of microtubules makes this possible because all of these processes require quick responses. Embryonic stem (ES) cells were first isolated from mouse embryos and they have two unique characteristics; they can be kept undifferentiated for many passages with a stable karyotype and they can be differentiated into any type of cells under appropriate conditions. The pluripotency of ES cells, their ease of manipulation in culture, and their ability to contribute to the mouse germ-line provides us a model of differentiation both in vitro and in vivo. In my thesis I focused on the cell division and neuronal differentiation of ES cells and developed two methods to understand the effects of microtubule dynamics in spindle assembly and chromosome segregation and to reveal the roles of different Microtubule Associated Proteins (MAPs) in the neuronal morphology formation.
In the first part, we developed a live-cell imaging method for ES cells to visualize, track and analyze the single cell behavior in a cell population over a time period. So far many techniques have been adapted and combined for imaging of cell lines, mainly for the cancer or immortalized ones. However, because ES cells are very prone to apoptosis, tend to form spheres and hard to stably label, it is quite tricky to image them in culture conditions. In our system, we combined the BAC-based gene expression with wide-field deconvolution microscopy for ES cells that are plated onto the laminin-511 coated surface and kept in CO2 independent culture conditions. This combined technique does not interfere with the growth of cells and keeps them healthy up to 24 hours on the microscope stage.
In the second part, we analyzed the effects of MAPs chTOG, EB1, Kif18A and MCAK in the overall spindle morphology and mitotic progression in mES cells. For this purpose, we utilized our stable TUBB-GFP and H2A-GFP cell lines along with our live-cell imaging set-up to reveal the effects of the above-mentioned proteins and the interplay among each other. By using RNAi method we either single or co-depleted the genes by siRNAs and measured the spindle length and width in RNAi conditions. We further analyzed the mitotic progression in H2A-GFP cell line in terms of the metaphase timing and the percentage of chromosome segregation errors. Our results showed that, EB1 depletion did not cause any significant changes in the overall spindle morphology or in the metaphase timing. However, the co-depletion of EB1 with chTOG partially rescued the sichTOG specific mini-spindle phenotype. siKif18A produced longer spindles without any change in the spindle width. Surprisingly, the co-depletion of antagonistic chTOG and Kif18A proteins had additive effects on the spindle dynamics and on mitotic progression in a way that spindle assembly was severely disrupted by the absence of these two proteins and as a result of this, both metaphase timing and chromosome missegregation levels increased significantly. These results overall indicate that MAPs have important roles in the regulation of dynamic instability and these proteins have an interplay among each other to be able to control the morphology of the spindle as well as the correct segregation of chromosomes into daughter cells.
In the last part, I will introduce you a new ES cell based differentiation and morphology model, which brings the advantages of high resolution imaging capacity, control over development and easy genetic manipulation and culturing. We have generated Tet-induced shRNA cell lines against chTOG, Kif18A and MCAK, which are also stably expressing TUBB-GFP. These labeled cells were mixed with unlabeled wild-type mES cells before differentiation at 1:1000 ratio and then they were differentiated into mouse cortical cells and spinal motor neurons. Our results showed that, all of the three genes could be successfully knocked-down by shRNA after 48 hours of Tet induction. After mixing the labeled and unlabeled cells, single neurons could be imaged at high resolution and their skeletons could be generated afterwards. The RNAi studies in shchTOG cell line showed that, the knock-down of this gene in early differentiation interferes with the neuronal differentiation.
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Bains, Babita. "Galling adelgids : gall formation, developmental morphology, characterization, and the genetic susceptibility of spruce." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/7411.
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Adelgids (Hemiptera: Adelgidae) are a small group of insects with complex life cycles and can threaten seed production in British Columbia (BC). Adelgids induce galls on the reproductive and vegetative shoots of spruce trees, reducing the number of future cone sites. Additionally, feeding on the cones and needles of alternate conifer hosts can reduce seed extraction efficiency, and cause discoloration and twisting of needles. Seed orchards are intensively managed for frequent and abundant seed production; hence losses incurred by adelgid pests are of high importance. Considering the complexity of insect-galler systems, there are many unanswered questions regarding the basic biology and habits of adelgids.
My research elucidates the influence of two adelgid life stages, the fundatrix and her offspring the gallicolae, through the use of manipulative laboratory experiments and botanical histological processes. It is evident that fundatrices induce the gall formation process and gallicolae activity completes gall formation. Considering the fundatrix is required to stimulate galling it would be sufficient to include only fundatrices in a monitoring system.
Additionally, I tested the theory that susceptibility to adelgid induced galling is under genetic control in spruce. Strong evidence of genetic control of susceptibility was observed with modest individual and high half- and full-sib family narrow-sense heritabilities of 0.17±0.09, 0.87±0.04, and 0.61±0.16, respectively. Breeding values for parental susceptibility to adelgid attack ranged between 0.25 and 0.76, indicating that selection for reduced susceptibility would be possible. These results suggest that adelgid galling susceptibility could be used as a screening criterion for parental inclusion in future seed orchard establishment.
Furthermore, I attempted to associate structurally unique galls with the inducing adelgid species. Detailed associations of adelgid species and their galls have not been rigorously determined. Rearing of gallicolae alates from various galls suggests that there can be a wide range of variation in the structure that a single species induces. Characterization of galls may allow orchard managers to understand what adelgid species are present and possibly avoid the taxonomic expertise required to identify adelgids.
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Forkan, Kathryn Marie 1958. "Characterization of aneuploids in pyrethrum, (Chrysanthemum cinerariaefolium), by cytology, morphology, and flow cytometry." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278167.
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Aneuploid plants are often used to locate genes or establish linkage, but first, they must be available. In Chrysanthemum cinerariaefolium Vis., a plant that produces pyrethrin, a relatively safe natural insecticide, aneuploids had not been categorized before. This research proposed to characterize aneuploids by morphology, cytology, nuclear DNA content, and pyrethrin composition. Aneuploid progeny of triploid parents were examined cytologically and morphologically. HPLC was used to establish pyrethrin composition and nuclear DNA content was calculated from flow cytometry. Five distinct phenotypes were found that may indicate aneuploid status, but not exact chromosome number. Exact chromosome number could only be distinguished cytologically, and ranged from 17 to 36, (2n = 18 for the diploid). Three trisomics were located. Nuclear DNA content indicated diploid or triploid status but not aneuploidy. Some of the aneuploids categorized may be useful in further research to locate pyrethrin genes or their linkages.
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Ogor, Julien. "Design of algorithms for the automatic characterization of marine dune morphology and dynamics." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2018. http://www.theses.fr/2018ENTA0005/document.
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Les dunes marines sont de grandes structures sédimentaires qui, ensemble, couvrent de larges zones appelées champs de dunes. Des dunes ont été découvertes dans tous les océans, de la côte jusqu'aux talus continentaux. Leur forme et mobilité sont des témoins du lien étroit qui existe entre le transport sédimentaire, l'hydrodynamique (courants marins) et la topographie du fond. L'étude des dunes est intéressante scientifiquement parlant, mais elle est également motivée par des enjeux économiques et environnementaux. Les dunes peuvent être étudiées de deux manières : La modélisation et l'analyse de données de terrain (granulométrie, courantométrie, données sismiques, données bathymétriques). Ces deux approches sont très différentes mais complémentaires. Avec l'amélioration des données Sondeur Multi-Faisceaux (SMF), il est maintenant possible de visualiser la morphologie des dunes et de suivre leur évolution de manière plus détaillée. Plusieurs méthodes automatiques d'analyse de la morphologie et de la dynamique des dunes ont été développées pour analyser les Modèles Numériques de Terrain (MNTs) construits à partir de ces données SMF. Pourtant, aucun ne permet d'estimer les valeurs de descripteurs morphologiques et dynamiques pour chaque dune. L'analyse et l'évaluation de ces descripteurs restent régionales avec le découpage des MNTs en régions rectangulaires. Seul un traitement manuel permet d'estimer ces descripteurs pour chaque dune. L'objectif de cette thèse est de développer des algorithmes automatiques permettant de quanti er la morphologie et la dynamique de chaque dune. Pour ce faire, une représentation des données SMF sous forme d'une tessellation triangulaire a été préférée au classique MNT régulier. Tout d'abord, les dunes doivent être extraites de la topographie du fond marin. Un algorithme par accroissement de régions avec adaptation de l'échelle d'analyse, issu de la géomorphométrie est proposé. Les crêtes de dunes sont d'abord extraites en combinant un algorithme de simplification de tessellations avec un algorithme d'extraction de lignes de crête. La résolution de la tessellation est adaptée par l'algorithme de simplification afin de faciliter l'extraction des lignes de crête. Les lignes de crête sont des objets bien définis en géométrie différentielle. Leur extraction s'appuie sur l'interprétation de cette définition appliquée à des modèles discrets du fond (tessellations). Les crêtes servent d'embryons à l'algorithme d'extraction des dunes. L'estimation des paramètres morphologiques des dunes (longueur, largeur, hauteur, etc.) découle de l'extraction automatique des dunes. L'utilisation d'une méthode de recalage non rigide (isométrique) pour la quantification de la dynamique est discutée. Des tessellations représentant la topographie d'un même champ de dunes à différents moments sont analysées par l'algorithme d'extraction des dunes. Ensuite, une dune est associée à une dune d'une autre tessellation qui lui correspond (même dune à un autre instant). La dynamique de chaque dune est quantifiée à partir des résultats de l'algorithme de recalage : les transformations permettant d'aligner différentes représentations d'une duneMarine dunes are large sedimentary mounds often organized in dunefields. Theyhave been discovered in oceans all around the globe, from continental rises to nearshore areas. These mobile seafloor structures reflect the unique and complex relationship between the sediment, the seafloor topography and the hydrodynamics (currents). Dunes are not only interesting at a scientific level. In fact, their study is also motivated by economic, safety and environmental reasons. The study of dunes can be divided into two complementary approaches: Modelling and analysis of in situ data (granulometry, current, bathymetric data).The increased quality of MultiBeam EchoSounder (MBES) data allows scientists to monitor and visualize the complexity of, both, dune morphology and dynamics. Au-tomatic methods to characterize dune morphology and dynamics using Digital TerrainModels (DTMs) have already been proposed. But, none does it at the dune scale. Mor-phological and dynamical descriptors are estimated for patches of the dunefield. Today, the evaluation of such descriptors for each dune can only be achieved manually.The objective of this thesis is to design automatic algorithms for the quantification of dune morphology and dynamics. A representation of MBES data as triangular meshes has been preferred to the usual gridded DTMs. The first stage consists of delineating dunes in the seafloor. A scale adaptative, region growing algorithm based on geomorphometry is proposed. The combination of mesh implification and crest extraction algorithms enables to accurately recover dune crest lines. The mesh simplification facilitates the crest extraction by adapting the mesh resolution. Crest extraction is based on the discrete interpretation of the definition of crest lines in differential geometry. The crests are, then, used as seed regions by the dune extraction algorithm
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Kang, Jiyuan. "MORPHOLOGY AND PERFORMANCE CHARACTERIZATION OF INTUMESCENT COATINGS FOR FIRE PROTECTION OF STRUCTURAL STEEL." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1544112058459729.
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Karimi, Abdolmaleki Mahmood. "Synthesis, Characterization, Thermodynamic, and Kinetic Studies of Vapochromic Pt(II) Complexes." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin152233710600004.
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Schulz, Steven E. "Geochemical, Petrologic, and Structural Characterization at Multiple Scales of Deformation Associated with the Punchbowl Fault, Southern California." DigitalCommons@USU, 1997. https://digitalcommons.usu.edu/etd/6707.
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Three traverses across the exhumed trace of the Punchbowl fault zone in the 11 Pelona Schist, southern California, were examined at the millimeter to kilometer scales to determine the morphology, deformation mechanisms, and geochemistry of the fault zone in schistose rocks. The Pelona Schist is predominantly a quartz-albite-muscovite-actinolite schist with associated minor metabasalts. The Punchbowl fault zone, which is exhumed 2-4 km, has 44 km of right lateral slip, and is composed of a fault core enveloped by a damaged zone.
The fault core is a region of extreme slip localization that records most fault displacement. Deformation in the fault core is dominated by grain-size reduction accompanied by fluid-dominated alteration, in contrast to the damage zone, where deformation is dominated by brittle and semi-brittle fracturing, cataclasis, and slip. Portions of the Punchbowl fault have multiple fault cores, with each fault core less than 10 cm thick. The thickness of a fault depends upon the type of deformation measured and the scale of observation. Mesoscopic fractures begin 50 m from the fault core, whereas the onset of fault-related microfractures occurs at approximately 40 m from the fault core . A geochemical signature based on whole-rock geochemistry suggests a fault thickness of less than 10 m. Grain-size reduction occurs over a 10 m thick region and mineralogic changes occur over a region 20-30 m thick. Reorientation of preexisting foliation occurs over a zone 30 m thick.
Fault-core morphology and textures are similar to those in the Punchbowl fault to the northwest, where it displaces sedimentary rocks, and the San Gabriel fault, which formed in crystalline rocks. This suggests that the processes that form foliated, finegrained, cataclasite-dominated fault cores of large displacement faults are similar for diverse lithologies. The composition of the fault core is variable along strike, with little geochemical or mineralogical homogenization. Whereas processes that form fault cores are similar, localized interaction of fluids caused compositional variability within the core. Changes in fault composition and fluid-rock interactions may result in different fault properties and behaviors.
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Baker, Brent A. "Characterization of skeletal muscle performance and morphology following acute and chronic mechanical loading paradigms." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5325.
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Thesis (Ph. D.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains xii, 270 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Baughman, Jessi Alan. "Solid-State NMR Characterization of the Structure and Morphology of Bulk Heterojunction Solar Cells." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1343136219.
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Reulier, Marie. "Renewable thermoplastic multiphase systems from dimer fatty acids : characterization of the "morphology-properties" relationships." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE007.
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Dans un contexte de développement durable, des matériaux thermoplastiques multiphasés biosourcés issus de dimères d’acides gras ont été élaborés pour développer une « eco-membrane » durable pour le bâtiment. Différentes formulations intégrant des polymères thermoplastiques biosourcés, polyuréthane thermoplastique (TPU) et polyamide (DAPA), des micro-charges minérales et des renforts cellulosiques ont été élaborées et analysées. Les relations « structures-propriétés » de ces systèmes multiphasés ont été étudiées. Les architectures macromoléculaires proches ont permis d’obtenir un certain degré de compatibilité entre les polymères. Les viscosités à l’état fondu du TPU et DAPA sont comparables, ce qui permet une bonne dispersion des phases du mélange lors de la mise en œuvre. Les propriétés mécaniques et la stabilité dimensionnelle des mélanges sont améliorées par ajout de micro-charges minérales. L’impact du facteur de forme des charges sur le module d’Young a été analysé et modélisé avec un modèle micro-mécanique. Des essais du type charge-décharge ont également été menés afin d’étudier le comportement à la fatigue des biocomposites. Enfin, les interactions et les affinités entre les renforts et polymères ont été approchées. Des modifications chimiques ont été développées à la surface des fibres afin de diminuer leurs caractères hydrophiles et d’améliorer la compatibilisation avec la matrice. L’impact de ces modifications sur l’interface fibres-matrice a ensuite été analysé. Les différentes études réalisées ont permis de sélectionner pas à pas les différents constituants de l’éco-membrane pour réaliser in fine un prototype prometteurIn the context of sustainable development, renewable multiphase systems from thermoplastics based on dimers of fatty acids were prepared to develop a renewable waterproofing material for building applications. Formulations based on thermoplastics, i.e. thermoplastic polyurethane (TPU) and polyamide (DAPA), mineral micro-fillers and cellulosic fibers were prepared with a special focus on the morphology-property relationships of the multiphase systems obtained thereof. The close macromolecular architectures promote a certain degree of compatibility between the polymers. Comparable viscosities in the melt state ensure a good dispersion of the matrices within each other during processing. The mechanical properties and dimensional stability were improved with micro-fillers. The effect of the aspect ratio of the fillers on the elastic properties was investigated and micro-mechanical modelling of the Young’s Modulus was performed. The fatigue behavior of the biocomposites was also examined through loading and unloading tests. Finally, interactions and affinities between the fibers and polymers were characterized. Chemical modifications were carried out on the surface of the fibers to decrease their hydrophilic nature and improve the fiber-matrix adhesion. The effect of the chemical modification was then investigated. Step-by-step, the studies carried out ensured the selection of the optimal components for a renewable waterproofing material enabling the production of a promising prototype
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Wood, Brian D. "Optical Characterization of Carbon Nanotube Forests." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4567.
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Carbon nanotube forests are vertically grown tubular formations of graphene. Samples were grown with an injection chemical vapor deposition method on substrates of silicon with various deposited layers and bare fused silica. The morphology of the forest is characterized by the height, density, and presence of defects. Total diffuse reflectance and transmittance measurements were taken in the 2-16 �m spectral range and correlated to the forest’s specific morphology. From these correlations, the conditions necessary to maximize the absorption of the forest were found and exploited to cater sample growth for specific substrates to make ideal absorbers. From the transmittance data, the absorption coefficient is found via Beer-Lambert’s Law and also correlated to sample morphology, giving us an indication of the height of the forest needed for ideal absorption. Two models were used to attempt to reproduce the experimental absorption coefficient: an effective medium theory using a Maxwell Garnett approximation and by treating the carbon nanotube forest as an effective cylindrical waveguide with walls of graphite. Each model leads to a set of fitting parameters providing a better physical understanding of the forests. It was found that the effective medium theory gave results loosely corroborated with electron microscopy, but had trouble fitting the experimental data, and the index of refraction it provides does not behave like a unified medium. The waveguide model fits the data well, but it requires more experimental evidence to be more conclusive. The theoretical models need more work, but fabrication of ideal absorbers has been achieved on various substrates providing framework for their usage in radiometry and spectroscopy.
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Riedlinger, Darren Andrew. "Characterization of PF Resol/Isocyanate Hybrid Adhesives." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/31366.
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Water-based resol phenol formaldehyde, PF, and organic polymeric methylenebis(phenylisocyanate), pMDI, are the two primary choices for the manufacture of exterior grade wood-based composites. This work addresses simple physical blends of pMDI dispersed in PF as a possible hybrid wood adhesive. Part one of this study examined the morphology of hybrid blends prepared using commercially available PF and pMDI. It was found that the blend components rapidly reacted such that the dispersed pMDI droplets became encased in a polymeric membrane. The phase separation created during liquid/liquid blending appeared to have been preserved in the cured, solid-state. However, substantial interdiffusion and copolymerization between blend components also appeared to have occurred according to measured cure rates, dynamic mechanical analysis, and atomic force microscopy. In the second part of this study a series of PF resins was synthesized employing the so-called â split-cookâ method, and by using a range of formaldehyde/phenol and NaOH/phenol mole ratios. These neat PF resins were subjected to the following analyses: 1) steady-state flow viscometry, 2) free formaldehyde titration, 3) non-volatile solids determination, 4) size exclusion chromatography, 5) quantitative solution-state 13C nuclear magnetic resonance, NMR, 6) differential scanning calorimetry, 7) parallel-plate oscillatory cure rheology, and 8) dielectric spectroscopy. The neat PF analytical results were unremarkable with one exception; NMR revealed that the formaldehyde/phenol mole ratio in one resin substantially differed from the target mole ratio. The neat PF resins were subsequently used to prepare of series of PF/pMDI blends in a ratio of 75 parts PF solids to 25 parts pMDI solids. The resulting PF/pMDI blends were subjected to the following analyses: 1) differential scanning calorimetry, 2) parallel-plate oscillatory cure rheology, and 3) dielectric spectroscopy. Similar to what was inferred in part one of this study, both differential scanning calorimetry (DSC) and oscillation cure rheology demonstrated that cure of the PF continuous phase was substantially altered and accelerated by pMDI. However within actual wood bondlines, dielectric analysis detected little variation in cure speed between any of the formulations, both hybrid and neat PF. Furthermore, the modulated DSC curing experiments detected some latent reactivity in the hybrid system, both during initial isothermal curing and subsequent thermal scanning. The latent reactivity may suggest that a significant diffusion barrier existed between blend components, preventing complete reaction of hybrid blends even after thermal scanning up to 200 °C. Part three of this work examined the bonded wood mode-I fracture performance of hybrid resins as a function of the resol formaldehyde/phenol ratio and also the alkali content. A moderate increase in unweathered fracture toughness was observed for hybrid formulations relative to neat PF. Following accelerated weathering, the durability of the hybrid blends was promising: weathered hybrid toughness was equivalent to that of weathered neat PF. While the resol F/P ratio and alkali content both influenced hybrid fracture toughness, statistical modeling revealed interaction between these variables that complicated result interpretation: the influence of hybrid alkali content depended heavily on each formulationâ s specific F/P ratio, and vice versa.Master of Science
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Bartolucci, Alberto. "Morphological characterization of ZnS thin films for photovoltaic applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10540/.
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Le celle solari a film sottile sono tra le alternative più promettenti nel campo fotovoltaico. La ricerca di materiali non tossici ed economici per la passivazione delle superfici è di fondamentale importanza. Il presente è uno studio sulla morfologia di film sottili di ZnS. I campioni analizzati sono stati cresciuti tramite DC sputtering a diversa potenza (range 50-150W) per studiare le connessioni tra condizioni di deposizione e proprietà strutturali. Lo studio è stato condotto mediante acquisizione di mappe AFM. E' stata effettuata un'analisi dei buchi (dips) in funzione della potenza di sputtering, per individuare il campione con la minore densità di dips in vista di applicazioni in celle solari a film sottile. I parametri strutturali, quali la rugosità superficiale e la lunghezza di correlazione laterale sono stati determinati con un'analisi statistica delle immagini. La densità e dimensione media dei grani sono state ricavate da una segmentazione delle immagini. Le analisi sono state svolte su due campioni di ZnO per fini comparativi. Tramite EFM sono state ottenute mappe di potenziale di contatto. Tramite KPFM si è valutata la differenza di potenziale tra ZnS e un layer di Al depositato sulla superficie. La sheet resistance è stata misurata con metodo a quattro punte. Dai risultati la potenza di sputtering influenza la struttura superficiale, ma in maniera non lineare. E' stato individuato il campione con la minore rugosità e densità di dips alla potenza di 75 W. Si è concluso che potenze troppo grandi o piccole in fase di deposizione promuovono il fenomeno di clustering dei grani e di aumentano la rugosità e densità di dips. E' emersa una corrispondenza diretta tra morfologia e potenziale di contatto alla superficie. La differenza di potenziale tra Al e ZnS è risultata inferiore al valore noto, ciò può essere dovuto a stati superficiali indotti da ossidi. Il campione risulta totalmente isolante.
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Simons, Kristin Jean. "Cloning and characterization of the wheat domestication gene, Q." Diss., Manhattan, Kan. : Kansas State University, 2005. http://hdl.handle.net/2097/135.
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Mendez, Israel Isaac. "The structural characterization of mammalian reovirus RNA-dependent RNA polymerase, capsid morphology, and capsid dynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62795.pdf.
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Devotta, Ashwin Moris. "Characterization & modeling of chip flow angle & morphology in 2D & 3D turning process." Licentiate thesis, Högskolan Väst, Forskningsmiljön produktionsteknik(PTW), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8671.
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Within manufacturing of metallic components, machining plays an important role and is of vital significance to ensure process reliability. From a cutting tool design perspective, tool macro geometry design based on physics based numerical modelling is highly needed that can predict chip morphology. The chip morphology describes the chip shape geometry and the chip curl geometry. The prediction of chip flow and chip shape is vital in predicting chip breakage, ensuring good chip evacuation and lower surface roughness. To this end, a platform where such a numerical model’s chip morphology prediction can be compared with experimental investigation is needed and is the focus of this work. The studied cutting processes are orthogonal cutting process and nose turning process. Numerical models that simulate the chip formation process are employed to predict the chip morphology and are accompanied by machining experiments. Computed tomography is used to scan the chips obtained from machining experiments and its ability to capture the variation in chip morphology is evaluated. For nose turning process, chip curl parameters during the cutting process are to be calculated. Kharkevich model is utilized in this regard to calculate the ‘chip in process’ chip curl parameters. High speed videography is used to measure the chip side flow angle during the cutting process experiments and are directly compared to physics based model predictions. The results show that the methodology developed provides the framework where advances in numerical models can be evaluated reliably from a chip morphology prediction capability view point for nose turning process. The numerical modeling results show that the chip morphology variation for varying cutting conditions is predicted qualitatively. The results of quantitative evaluation of chip morphology prediction shows that the error in prediction is too large to be used for predictive modelling purposes.
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Deng, Jianjun. "Interfacial Characterization of Polyhedral Oligomeric Silsesquioxane (POSS) Amphiphiles and Polymer Blends: Thermodynamics, Morphology, and Rheology." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27126.
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Over the past two decades one class of oligomers, polyhedral oligomeric silsesquioxanes (POSS), has attracted considerable attention because of their unique hybrid organic/inorganic molecular structures and nanoscopic sizes. While surface and interfacial properties may play a key role in many potential POSS applications, relatively little is actually known about the surface properties of POSS. This dissertation provides studies of the interfacial aspects of both POSS molecules and POSS/polymer blends at the air/water interface (A/W) through surface pressure-area per molecule (π-A) isotherm, Brewster angle microscopy (BAM), and interfacial stress rheometry (ISR) studies.
Results for POSS Langmuir thin films at A/W show that trisilanol-POSS derivatives are a new class of amphiphiles, that exhibit multiple phase transitions in going from traditional 2D Langmuir monolayers (1 POSS molecule thick) to various 3D multilayer films upon compression. With small length/diameter ratios and bulky shapes, the monolayer phase behavior and packing states of different POSS are simpler than the traditional rod-like lipids. Meanwhile trisilanol-POSS derivatives have very different collapse behavior and multilayer organization showing strong substituent effects even though they have similar molecular sizes. While trisilanolisobutyl-POSS (TiBuP) monolayers undergo collapse around π ≈ 18 mNm⁻¹ and form various ordered or disordered solid-like 3D aggregates at different compression rates, trisilanolcyclohexyl-POSS (TCyP) monolayers collapse into trilayers via instantaneous nucleation with hemispherical edge growth around π ≈ 3.7 mNm⁻¹. ISR results reveal three different non-Newtonian flow regimes that correlate with phase transitions in the Pi-A isotherms. Further symmetric compression after trilayer formation induces TCyP thin films to self-assemble into highly ordered crystalline-like hydrophobic multilayers (≈8 POSS molecule thick) with unique rod-like morphologies, which are dramatically different from –collapsed– morphologies seen in other systems.
By treating POSS derivatives as ideal nanofiller for studying confinement effects on filled polymer systems, amphiphilic poly(dimethylsiloxane) (PDMS) derivatives with different polar functional groups are studied as blends with TiBuP and octaisobutyl-POSS at A/W to resolve one of the key challenges for current nanocomposite applications: How to control nanofiller dispersion in polymer matrices? The results in this dissertation reveal that introducing polar groups into polymeric matrix polymers is a good way to control dispersion.Ph. D.
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Mukherjee, Anika. "Pattern Recognition and Machine Learning as a Morphology Characterization Tool for Assessment of Placental Health." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42731.
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Introduction: The placenta is a complex, disk-shaped organ vital to a successful pregnancy and responsible for materno-fetal exchange of vital gases and biochemicals. Instances of compromised placental development or function – collectively termed placenta dysfunction - underlies the most common and devastating pregnancy complications observed in North America, including preeclampsia (PE) and fetal growth restriction (FGR). A comprehensive histopathology examination of the placenta following delivery can help clarify obstetrical disease etiology and progression and offers tremendous potential in the identification of patients at risk of recurrence in subsequent pregnancies, as well as patients at high risk of chronic diseases in later life. However, these types of examinations require a high degree of specialized training and are resource intensive, limiting their availability to tertiary care centers in large city centres. The development of machine learning algorithms tailored to placenta histopathology applications may allow for automation and/or standardization of this important clinical exam – expanding its appropriate usage and impact on the health of mothers and infants. The primary objective of the current project is to develop and pilot the use of machine learning models capable of placental disease classification using digital histopathology images of the placenta.
Methods: 1) A systematic review was conducted to identify the current methods being applied to automate histopathology screening to inform experimental design for later components of the project. Of 230 peer-reviewed articles retrieved in the search, 18 articles met all inclusion criteria and were used to develop guidelines for best practices. 2) To facilitate machine learning model development on placenta histopathology samples, a villi segmentation algorithm was developed to aid with feature extraction by providing objective metrics to automatically quantify microscopic placenta images. The segmentation algorithm applied colour clustering and a tophat transform to delineate the boundaries between neighbouring villi. 3) As a proof-of-concept, 2 machine learning algorithms were tested to evaluated their ability to predict the clinical outcome of preeclampsia (PE) using placental histopathology specimens collected through the Research Centre for Women’s and Infant’s Health (RCWIH) BioBank. The sample set included digital images from 50 cases of early onset PE, 29 cases of late onset PE and 69 controls with matching gestational ages. All images were pre-processed using patch extraction, colour normalization, and image transformations. Features of interest were extracted using: a) villi segmentation algorithm; b) SIFT keypoint descriptors (textural features); c) integrated feature extraction (in the context of deep learning model development). Using the different methods of feature extraction, two different machine learning approaches were compared - Support Vector Machine (SVM) and Convolutional Neural Network (CNN, deep learning). To track model improvement during training, cross validation on 20% of the total dataset was used (deep learning algorithm only) and the trained algorithms were evaluated on a test dataset (20% of the original dataset previously unseen by the model).
Results: From the systematic review, 5 key steps were found to be essential for machine learning model development on histopathology images (image acquisition and preparation, image preprocessing, feature extraction, pattern recognition and classification model training, and model testing) and recommendations were provided for the optimal methods for each of the 5 steps. The segmentation algorithm was able to correctly identify individual villi with an F1 score of 80.76% - a significantly better performance than recently published methods. A maximum accuracy of 73% for the machine learning experiments was obtained when using textural features (SIFT keypoint descriptors) in an SVM model, using onset of PE disease (early vs. late) as the output classification of interest.
Conclusion: Three major outcomes came of this project: 1) the range of methods available to develop automated screening tools for histopathology images with machine learning were consolidated and a set of best practices were proposed to guide future projects, 2) a villi segmentation tool was developed that can automatically segment all individual villi from an image and extract biologically relevant features that can be used in machine learning model development, and 3) a prototype machine learning classification tool for placenta histopathology was developed that was able to achieve moderate classification accuracy when distinguishing cases of early onset PE and late onset PE cases from controls. The collective body of work has made significant contributions to the fields of placenta pathology and computer vision, laying the foundation for significant progress aimed at integrating machine learning tools into the clinical setting of perinatal pathology.
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Yoon, Heejeong. "Purification and characterization of malate dehydrogenase and 6- phosphogluconate dehydrogenase from Haemophilus influenzae." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/54472.
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Haemophilus influenzae, the primary causative factor in bacterial meningitis, displays a unique growth requirement for intact NAD. Selective inhibitors of the pyridine nucleotide-requiring enzymes from H. influenzae could have a pronounced effect on growth of the organism.
Haemophilus malate dehydrogenase was purified 109-fold with a 26% recovery through a 4-step procedure involving salt fractionation, and hydrophobic and dye affinity chromatography. The purified enzyme was demonstrated to be a dimer of M,= 61,000. Initial velocity, product, and dead-end inhibition studies were consistent with an ordered bi-bi mechanism in which NAD is the first substrate bound to the enzyme. Several NAD analogs structurally altered in either the pyridine or purine moiety functioned as coenzymes in the reaction catalyzed. Selective interactions occurring at the coenzyme binding sites were investigated. Coenzyme-competitive inhibition by adenosine derivatives demonstrated important interactions of the pyrophosphate moiety of the coenzyme. Positive chain length effects in the coenzyme-competitive inhibition by aliphatic carboxylic acids indicated the presence of a hydrophobic region close to the pyrophosphate region at the coenzyme binding site. Several structural analogs of NAD and malate were evaluated as selective inhibitors of the enzyme. The enzyme was inactivated by incubation with diethylpyrocarbonate whereas no inactivation was observed with sulfhydryl reagents.
Haemophilus influenzae 6-phosphogluconate dehydrogenase was purified 308-fold with a 16% recovery through a 4-step chromatographic procedure involving a PhenylSepharose hydrophobic column, and affinity chromatography on Matrex gel Green A, Matrex gel Red A, and 2',5’ADP-Sepharose resin. The purified enzyme was demonstrated to be a dimer of M,= 70,000. Initial velocity studies of 6-phosphogluconate oxidation indicated a sequential reaction mechanism. Although certain product and dead-end inhibition studies were consistent with an ordered mechanism, the direct binding of 6-phosphogluconate in protection experiments did not support a strictly ordered reaction sequence. Inhibition by adenosine derivatives indicated that the 2’-phosphate is important in binding to the coenzyme binding site of the enzyme.
The 3-acetylpyridine analogs of NAD and NADP which support growth of H. influenzae were demonstrated to function as coenzymes with the two dehydrogenases studied. The most effective inhibitors of the purified malate dehydrogenase and 6-phosphogluconate dehydrogenase were observed to inhibit the growth of Haemophilus influenzae. However, the most potent inhibition of growth by 3-aminopyridine analogs of NAD and NADP could not be explained on the basis of interactions of these analogs with the two dehydrogenases studied.Ph. D.
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Yip, Chi-wai, and 葉志偉. "Characterization of the cell entry mechanism of infectious bursal disease virus." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44756306.
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Fox, Sean J. "Identification and Characterization of Genetic Factors Involved in Candida-Bacterial Interactions." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etd/2277.
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Throughout existence, fungi and bacteria have long shared ecological niches and thus engage in numerous interactions to mutually enhance survival or antagonistically gain competitive advantages. Of importance to human health are those interactions that involve bacteria with the opportunistic fungi, Candida albicans. An important virulence factor of C. albicans is the ability to control morphology, which allows the transition between yeast, pseudohyphal, and hyphal phenotypes. Morphological control in C. albicans is governed by quorum sensing and the secreted autoregulatory molecule farnesol. Quorum sensing allows individual cells to sense the environment and respond as a group. Bacteria also use quorum sensing to communicate and control virulence. Despite their abundance in nature, very little is known about the interactions of C. albicans with bacteria on a genetic and molecular level. The objective of our research is to identify the genetic elements involved in C. albicans-bacterial interactions and characterize the genes that may participate in these relationships. To accomplish this, we screened a C. albicans mutant library for the ability to filament in the presence of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, where 3 typically, these three bacterial species inhibit C. albicans filamentation. We identified 836 C. albicans mutants that displayed a filamentous phenotype in the presence of bacteria. Collectively, 295 of these mutants filamented in the presence of all 3 bacterial species. Candidates were subsequently sequenced to identify the location of the mutation and the affected genetic element. CDR4, a putative ABC transporter, and ALS6, a putative adhesion, were further characterized for their specific involvement in Candida-bacterial interactions. Using a filamentation assay, cdr4 and als6 deletion strains demonstrated a decreased response to the inhibitory effects of farnesol, as well as bacterial molecules known to inhibit the production of hyphal-filaments. Additionally, the ability of cdr4 and als6 deletion strains to attach and form biofilms was significantly enhanced even in the presence of farnesol and bacterial inhibitors. The results of this study contribute to the body of knowledge involving polymicrobial interactions and these findings may lead to new antifungal targets for therapeutic interventions.
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Gustafsson, Eva. "Characterization of particulate matter from atmospheric fluidized bed biomass gasifiers." Doctoral thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-11473.
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Through biomass gasification, biomass can be converted at high temperature to a product gas rich in carbon monoxide, hydrogen, and methane. After cleaning and upgrading, the product gas can be converted to biofuels such as hydrogen; methanol; dimethyl ether; and synthetic diesel, gasoline, and natural gas. Particulate matter (PM) is formed as a contaminant in the gasification process, and the aim of this work was to develop and apply a method for sampling and characterization of PM in the hot product gas. A particle measurement system consisting of a dilution probe combined in series with a bed of granular activated carbon for tar adsorption was developed, with the aim of extracting a sample of the hot product gas without changing the size distribution and composition of the PM. The mass size distribution and concentration, as well as the morphology and elementary composition, of PM in the size range 10 nm to 10 µm in the product gas from a bubbling fluidized bed (BFB) gasifier, a circulating fluidized bed (CFB) gasifier and an indirect BFB gasifier using various types of biomass as fuel were determined. All gasifiers and fuels displayed a bimodal particle mass size distribution with a fine mode in the <0.5 µm size range and a coarse mode in the >0.5 µm size range. Compared with the mass concentration of the coarse mode the mass concentration of the fine mode was low from all gasifiers. The evaluation of the results for the fine-mode PM was complicated by condensing potassium chloride for the CFB gasifier when using miscanthus as fuel and by condensing tars for the indirect BFB gasifier when using wood C as fuel. The mass concentration of the coarse-mode PM was higher from the CFB gasifier than from the two BFB gasifiers. The coarse-mode PM from the BFB gasifier when using wood A as fuel was dominated by char. In the CFB gasifier the coarse-mode PM was mainly ash and bed material when using all fuels. The coarse-mode PM from the indirect BFB gasifier when using wood C as fuel was mainly ash.
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Jenkins, Shawn Eric. "Synthesis and spinning of a new thermotropic liquid crystallinepolymers : characterization of fiber morphology and mechanical properties." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/8557.
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Wong, Edith Denise. "Characterization of components required to maintain mitochondrial DNA and mitochondrial morphology in the yeast, Saccharomyces cerevisiae /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Huffman, John Alexander. "Development and application of new instrumental techniques for real-time characterization of aerosol volatility and morphology." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337107.
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Hirschle, Patrick [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Controlling functionalization and morphology of MOF particles - employing novel characterization techniques / Patrick Hirschle ; Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1227188129/34.
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Rinehart, Aidan Walker. "A Characterization of Seal Whisker Morphology and the Effects of Angle of Incidence on Wake Structure." Cleveland State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=csu1483991011265196.
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Tuschel, David Daniel 1957. "A CHARACTERIZATION OF THE OXIDATION-REDUCTION CYCLE AND SURFACE MORPHOLOGY OF ELECTROCHEMICAL SURFACE ENHANCED RAMAN SCATTERING." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277026.
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Valverde, Miguel Angel Galarreta. "Representação e quantificação de redes vasculares a partir de imagens de angiografia tridimensional." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/45/45134/tde-15022018-163753/.
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As imagens de Angiografia por Ressonância Magnética (angio-RM) e Tomografia Computadorizada (angio-TC) são ferramentas amplamente usadas em processos de quantificação vascular e no diagnóstico de doenças cardiovasculares, as quais são consideradas entre as principais causas de morte. Contudo, a análise dos vasos em larga escala a partir das imagens é dificultada, tanto pela variabilidade natural dos vasos no corpo humano, quanto pela grande quantidade de dados disponíveis. Além disso, os métodos de quantificação existentes, usualmente extraem as características a partir dos esqueletos, ou até mesmo das próprias imagens de angiografia, razão pela qual tais métodos podem fazer necessária a reanálise das imagens repetidas vezes. Com o intuito de facilitar a análise e de fornecer uma ferramenta de apoio ao diagnóstico, neste trabalho são apresentados um modelo de representação textual de redes vasculares e uma metodologia de quantificação vascular automática, que é feita a partir dessa representação. A representação é obtida a partir da segmentação de imagens volumétricas de angio-RM e angio-TC, seguida da extração de trajetórias e diâmetros de redes vasculares. Tal representação é híbrida, combinando grafos e uma sequência textual de instruções, e permite não apenas a extração de caraterísticas morfológicas da rede vascular, como também a compressão das imagens e, ainda, a reconstrução de imagens similares às imagens originais. A partir das características extraídas, foram realizados estudos comparativos entre arquiteturas vasculares, o que é feito tanto por meio do uso de imagens sintéticas, como por meio de imagens reais, imagens nas quais foi possível encontrar diferenças entre arquiteturas, além de viabilizar a caracterização de aneurismas em um indivíduo. Paralelamente, desenvolvemos um método que permite identificar similaridade entre segmentos vasculares, o que por sua vez possibilita o reconhecimento e rotulação de segmentos em um conjunto de redes vasculares. A metodologia por nós desenvolvida deve também auxiliar no desenvolvimento de processos de classificação de vasos sanguíneos, de ferramentas para o diagnóstico automático de doenças vasculares, e para a melhora de técnicas utilizadas na prática clínica.Magnetic Resonance Angiography (angio-MR) and Computed Tomography Angiography (angio-TC) are widely used imaging techniques used for vascular quantification and the diagnosis of cardiovascular diseases, considered one of the main causes of death. Blood vessel analysis using angiographic images is intrisically difficult because of the natural human vessel variability and the large amount of information. Additionally, most quantification methods perform the analysis of entire datasets, which can be very time consuming when they need to be reanalyzed. With the aim of reducing these problems and to provide a tool to aid diagnosis, we propose a textual representation model for vascular networks and an automatic vascular quantification methodology. The representation is obtained from volumetric image segmentation of angio-MR and angio-TC, followed by the extraction of the trajectory and the blood vessel diameters. This representation is hybrid in nature, combining graphs and a sequence of textual instructions, allowing for the extraction of morphological features, image compression, and the synthesis of angiographic images. Using extracted features derived from the model, comparative studies of vascular architecture can be performed. Experiments were made using synthetic and real images, in which was possible to find structural differences that make feasible to characterize abnormalities such as aneurysms. Also, a vessel similarity identification method was developed, which makes it possible to recognize vessel segments and label them in a set of vessel networks. The proposed methodology should aid in blood vessel classification processes, automatic diagnosis of cardiovascular diseases, and allow development of methods and applications that could be used in the clinical practice.
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Hilding, Jenny Marie. "Characterization and Applications of Multiwalled Carbon Nanotubes." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_diss/303.
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Multiwalled carbon nanotubes (MWNTs) have attracted great interest during thelast decade due to their possession of a unique set of properties. In addition totheir strength, MWNTs have well defined morphologies, with large aspect ratiosand pores in the meso range, and intriguing transport properties, such as highelectrical and thermal conductivity.We are interested in how variations in the MWNT morphology affect areas ofpossible engineering applications. We have identified morphology as a criticalelement for the performance of MWNTs in engineering applications. Specificareas studied and reported here spans from surface adsorption and capillarycondensation, to dispersion and dispersion processes, and transport propertiesin relation to MWNT aspect ratio. This wide range of exploration is typicallyneeded for evaluating opportunities for new materials.MWNTs can be used in different types of adsorption systems and it should bepossible to tailor the MWNT morphology to suit a specific adsorption process.We found that the major part of butane, our model gas, adsorbs on the externalMWNT and only a small fraction ends up in the pores.The unusually large aspect ratio makes MWNTs ideal as fillers in polymermatrixes. Since MWNTs are electrically conductive, it is possible to align theMWNTs in the matrix before curing. We investigated the effect of AC-fields onaqueous MWNT dispersions and the possibility to align MWNTs in an electricalfield.It is also necessary to develop suitable dispersion methods, to enable theproduction of homogeneous dispersions and composites. We studied a numberof different mechanical dispersion methods and their effect on the MWNTmorphology.
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Subramanian, Sankar. "SYNTHESIS AND DEVICE CHARACTERIZATION OF FUNCTIONALIZED PENTACENES AND ANTHRADITHIOPHENES." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/588.
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Research on pi-conjugated organic materials in the recent past has produced enormous developments in the field of organic electronics and it is mainly due to their applications in electronic devices such as organic field effect transistors (OFETs), organic light emitting diodes (OLEDs) and organic photovoltaic cells (OPVs). The primary goal of this research work is to design and synthesize high performing charge transport organic semiconductors. One of the criteria for better performance of the organic thin film transistor (OTFT) is to have high uniform thin film morphology of the organic semiconductor layer on the substrate. The first project in this dissertation has been directed towards improving the thin film morphology of the functionalized pentacenes through liquid crystalline behaviour. The results have suggested the possibility of thermotropic liquid crystalline phases in 6,13-bis(diisopropylhexylsilylethynyl) pentacene which has no pi-stacking in its solid state and the presence of silyl group at the peri-position is crucial for the stability of the functionalized pentacenes. In the second project, i have investigated the effect of alkyl groups with varying chain length on the anthradithiophene chromophore on the performance of the charge transporting devices. Organic blend cell based on solution processable 2,8-diethyl-5,12-bis(triethylsilylethynyl) anthradithiophene has showed 1% power conversion efficiency and the performance is mainly attributed to the large crystalline phase segregation of the functionalized anthradithiophene from the amorphous soluble fullerene derivative matrix. OTFT study on alkyl substituted functionalized anthradithiophenes suggested the need of delegate balance between thin film morphology and the crystal packing. Third project has been directed towards synthesizing halogen substituted functionalized anthradithiophenes and their influence in the performance of OFETs. OTFT made of 2,8-difluoro-5,12-bis(triethylsilylethynyl) anthradithiophene produced devices with thin film hole mobilities greater than 1 cm2/Vs. The result suggested that the device is not contact limited rather this high performance OTFTs are due to the contact induced crystallinity of the organic semiconductor.
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Sloan, Stakleff Kimberly Denise. "CHARACTERIZATION OF UROKINASE PLASMINOGEN ACTIVATOR RECEPTOR (UPAR) AND INTEGRIN SUBUNITS IN BREAST CARCINOMA CELL LINES WITH DIVERSE INVASIVE CAPACITIES." Kent State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1195663733.
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Woller, Kevin Benjamin. "Characterization of the dynamic formation of nano-tendril surface morphology on tungsten while exposed to helium plasma." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112365.
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Thesis: Sc. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 133-140).
Tungsten undergoes surface morphology changes on the nanometer scale when subjected to low energy helium ion bombardment. This is due in part to the ion bombardment causing tungsten atoms to move on the surface, but also because of helium implantation and bubble development in the near surface at a depth < 30 nm. At high enough surface temperatures, T/TM >/~ 0.2, where TM is the melting temperature, nanoscale tendrils form on the surface and grow longer with additional bombardment by helium, but will decompose at the same temperature without helium bombardment. A tungsten surface that develops a densely packed layer of nano-tendrils over macroscopic areas greater than the grain size is referred to as tungsten fuzz, and is under intense study in fusion energy research, both for better understanding of how tungsten fuzz forms and of how tungsten fuzz affects the performance of plasma-facing components. The necessity of helium irradiation of the surface to induce nano-tendril growth motivates investigation into the dynamic process of helium implantation and accumulation in the surface. In this thesis, in situ elastic recoil detection is developed and used to measure the dynamic concentration of helium within a tungsten surface during the active growth of tungsten fuzz. During the development of in situ elastic recoil detection analysis, a variant of tungsten nano-tendril growth was discovered featuring drastically isolated bundles of nano-tendrils that grow at a higher rate than tungsten fuzz. The variation in nano-tendril morphology is correlated with incident helium ion energy modulation. The dependence on ion energy modulation and isolated nature of the nano-tendril bundles reveals clearly that nano-tendril growth is sensitive to surface kinetic effects. In this thesis, the structure and parameter space of the newly discovered nano-tendril bundle growth is analyzed with a suite of electron-based surface science techniques.
by Kevin Benjamin Woller
Sc. D.
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Schlea, Michelle Renee. "Processing and characterization of high performance polyimide nanocomposites." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39557.
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The goal of this work was to achieve a homogeneous morphology of carbon nanotubes in a polyimide matrix, characterize the resulting nanocomposite properties, and understand structure-property relationships. Melt-mixing was used as an effective method for dispersing multiwall nanotubes and carbon nanofibers in a phenylethynyl terminated imide resin where aggregation occurred only in particle-saturated systems. Particle network formation within the nanocomposites was studied using rheology and impedance spectroscopy; results showed that the electrical percolation threshold occurred at a lower particle loading than the rheological percolation threshold, consistent with the oligomer size in comparison to the distance for electrical conductivity (~5 nm). Thermomechanical analysis showed that the addition of nanoparticles enhanced the polyimide storage modulus and thermal behavior indicated that the nanoparticles restricted polymer motion to higher temperatures. A study of the cure mechanism of the oligomer with and without nanoparticles showed that the nanoparticles reduced the activation energy required for cure initiation while increasing the obtainable extent of cure at various isothermal temperatures. The work presented in this dissertation shows that an easy, time effective processing method can be used to homogeneously disperse nanoparticles in an imide oligomer, and the resulting nanocomposites exhibit enhanced properties. A business plan is also presented that reflects the market potential of this technology.
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Bowen, James M. "Physicochemical characterization of discrete weapons grade plutonium metal particles originating from the 1960 BOMARC incident." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384850163.
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Boone, Jason Nathaniel 1976. "Characterization of novel neural stem cell populations in the Drosophila central nervous system." Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/8160.
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xi, 88 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.Neuroblasts are the neural stem cells of the Drosophlia central nervous system. They are large cells that divide asymmetrically to renew another neuroblast and generate a smaller ganglion mother cell (gmc) that will divide once to produce two neurons. Combining genetic lineage tracing experiments with cell fate markers I isolated two separate neural stem cell populations with distinct locations and cellular behaviors in the larval brain. In my first chapter I introduce the central nervous system of Drosophila and in the next two sections of chapter I, I introduce the development of the optic lobe and central brain, two separate structures of the central nervous system. In my second chapter I characterize the lineage relationship of cells within the developing larval optic lobe and use cell fate markers to determine the identity of these cells. Next I examine the effect of spindle orientation on cell fate within epithelial cells of the optic lobe. In my third chapter I characterize another novel neural stem cell lineage in the larval brain containing GMCs with greater proliferation potential than a "canonical" GMC, and I term these, transit amplifying gmcs (TA-GMCs). Further I show that the parent neuroblast of these novel TA-GMCs does not asymmetrically segregate the fate determinant Prospero (Pros) thereby producing a GMC with greater proliferation potential. Finally I show that TA-GMCs do asymmetrically segregate the fate determinant Pros, divide slowly and give rise to up to 10 neurons which normal gmcs never do. In my fourth chapter I show preliminary work on the characterization of a mutation that causes excessive production of neuroblasts specifically in novel TA-GMC lineages. These findings reveal novel neural stem cell lineages, patterns of asymmetric cell division and patterns of neurogenesis that could aid in our understanding of neural stem cell biology and tumorogenesis. This dissertation includes both my previously published and my co-authored materials.
Adviser: Chris Doe