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Zandian, Vahid. "Factors affecting the rate of devitrification of fused silica powder." Thesis, Staffordshire University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238383.
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Passos, Sheila Pestana. "Adesão e grau de conversão: efeito das cores da cerâmica e do agente de fixação resinoso /." São José dos Campos : [s.n.], 2010. http://hdl.handle.net/11449/105544.
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Resumo: O objetivo deste trabalho foi avaliar a translucidez de diferentes cores da cerâmica, o grau de conversão de diferentes cores do agente de fixação resinoso e a resistência de união entre a cerâmica e a dentina, variando as cores da cerâmica e do agente de fixação e o tempo de fotoativação. A hipótese é que quanto mais escuros o agente de fixação resinoso e a cerâmica, menor translucidez, menor conversão dos monômeros, mais baixa será a resistência adesiva, portanto maior tempo necessário para fotoativação. Três discos da cerâmica Vita VM7 com dimensão de 20 x 2 mm nas cores Base Dentine 0M1, Base Dentine 2M2 e Base Dentine 5M3 e dois discos com 20 x 2,5 mm da mesma cerâmica nas cores Base Dentine 0M1 e Base Dentine 5M3 foram usados para determinar a percentagem de translucidez através do espectrofotômetro MiniScan. Para se obter o grau de conversão (GC), os cp do agente de fixação (Variolink II; A3 Amarelo e transparente; espessura: 100 μm) foram fotoativados sob um bloco cerâmico (espessura: 2 mm; Base Dentine 0M1, Base Dentine 2M2 e Base Dentine 5M3) por 20 ou 40 s. Cp fotoativados sem o bloco cerâmico foram usados como controle. Dezesseis grupos (n=3) foram avaliados. Espectrometria de Micro- ATR/FTIR foi utilizada para avaliar a extensão da polimerização de todos os cp depois de 24 h. A %GC foi calculada e os dados foram analisados através de ANOVA 1-fator e teste de Tukey ( =0,05). Para avaliar adesão, a dentina da superfície oclusal de 80 molares humanos hígidos foi exposta e condicionada com ácido fosfórico 37% e adesivo (Excite DSC). Oitenta blocos (7,2 x 7,2 x 2,5 mm) da mesma cerâmica, nas cores Base Dentine 0M1 e Base Dentine 5M3, foram confeccionados de acordo com as instruções do fabricante. A superfície cerâmica foi tratada com ácido fluorídrico 10% por 60 s e silanizada. Os blocos cerâmicos de cada cor foram cimentados... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: The aim of this study was to evaluate the translucency of different ceramic shades, degree of conversion of different resin cement and the bond strength between a feldspathic ceramic and dentin using different resin cement and ceramic shades, and the activation time. The hypothesis is the darker the resin cement and ceramic, lower the translucency; the lower the degree of monomers conversion, lower the bond strength, then the activation time should be higher. Three discs of Vita VM7 ceramic with 20 x 2 mm and shades: Base Dentine 0M1, Base Dentine 2M2 and Base Dentine 5M3, and two discs with 20 x 2.5 mm of the same ceramic and shades: Base Dentine 0M1 and Base Dentine 5M3 were used to determine the translucency percentage of each sp using the MiniScan espectrophotometer. For measure the degree of conversion (DC), the resin cement (Variolink II; A3 Yellow and transparent) specimens (thickness: 100 μm) were photocured under a ceramic block (2mm-thick; Base Dentine 0M1, Base Dentine 2M2 and Base Dentine 5M3) for 20 or 40 s. Specimen photocured without the ceramic block were used as control. Sixteen groups (n=3) were evaluated. Micro-ATR/FTIR spectrometry was used to evaluate the extent of polymerization of all sp after 24 h. The %DC was calculated and the data were analyzed using ANOVA 1-way and Tukey test ( =0,05). For the microtensile bond strength test, the occlusal dentin surface of eighty molars were exposed and etched with 37% phosphoric acid and an adhesive (Excite DSC) was applied. Eighty blocks (7.2 x 7.2 x 2.5 mm) of Base Dentine 0M1 and Base Dentine 5M3 of Vita VM7 ceramic were produced according to the manufacturers. The ceramic surface was etched with 10% hydrofluoric acid for 60 s, followed by the application of a silane agent and a dualcured resin cement (Variolink II; base and catalyst: A3 Yellow; base and catalyst: transparent), according to the manufacturers' ...(Complete abstract click electronic access below)
Orientador: Estevão Tomomitsu Kimpara
Coorientador: Amin Sami Rizkalla
Banca: Anderson Pinheiro de Freitas
Banca: Marco Antonio Bottino
Banca: Mario Alexandre Coelho Sinhoreti
Banca: Paula Komori
Doutor
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Passos, Sheila Pestana [UNESP]. "Adesão e grau de conversão: efeito das cores da cerâmica e do agente de fixação resinoso." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/105544.
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passos_sp_dr_sjc.pdf: 3848792 bytes, checksum: 3fb1f1393e2dc87d50d66555ecfbb5ae (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste trabalho foi avaliar a translucidez de diferentes cores da cerâmica, o grau de conversão de diferentes cores do agente de fixação resinoso e a resistência de união entre a cerâmica e a dentina, variando as cores da cerâmica e do agente de fixação e o tempo de fotoativação. A hipótese é que quanto mais escuros o agente de fixação resinoso e a cerâmica, menor translucidez, menor conversão dos monômeros, mais baixa será a resistência adesiva, portanto maior tempo necessário para fotoativação. Três discos da cerâmica Vita VM7 com dimensão de 20 x 2 mm nas cores Base Dentine 0M1, Base Dentine 2M2 e Base Dentine 5M3 e dois discos com 20 x 2,5 mm da mesma cerâmica nas cores Base Dentine 0M1 e Base Dentine 5M3 foram usados para determinar a percentagem de translucidez através do espectrofotômetro MiniScan. Para se obter o grau de conversão (GC), os cp do agente de fixação (Variolink II; A3 Amarelo e transparente; espessura: 100 μm) foram fotoativados sob um bloco cerâmico (espessura: 2 mm; Base Dentine 0M1, Base Dentine 2M2 e Base Dentine 5M3) por 20 ou 40 s. Cp fotoativados sem o bloco cerâmico foram usados como controle. Dezesseis grupos (n=3) foram avaliados. Espectrometria de Micro- ATR/FTIR foi utilizada para avaliar a extensão da polimerização de todos os cp depois de 24 h. A %GC foi calculada e os dados foram analisados através de ANOVA 1-fator e teste de Tukey ( =0,05). Para avaliar adesão, a dentina da superfície oclusal de 80 molares humanos hígidos foi exposta e condicionada com ácido fosfórico 37% e adesivo (Excite DSC). Oitenta blocos (7,2 x 7,2 x 2,5 mm) da mesma cerâmica, nas cores Base Dentine 0M1 e Base Dentine 5M3, foram confeccionados de acordo com as instruções do fabricante. A superfície cerâmica foi tratada com ácido fluorídrico 10% por 60 s e silanizada. Os blocos cerâmicos de cada cor foram cimentados...
The aim of this study was to evaluate the translucency of different ceramic shades, degree of conversion of different resin cement and the bond strength between a feldspathic ceramic and dentin using different resin cement and ceramic shades, and the activation time. The hypothesis is the darker the resin cement and ceramic, lower the translucency; the lower the degree of monomers conversion, lower the bond strength, then the activation time should be higher. Three discs of Vita VM7 ceramic with 20 x 2 mm and shades: Base Dentine 0M1, Base Dentine 2M2 and Base Dentine 5M3, and two discs with 20 x 2.5 mm of the same ceramic and shades: Base Dentine 0M1 and Base Dentine 5M3 were used to determine the translucency percentage of each sp using the MiniScan espectrophotometer. For measure the degree of conversion (DC), the resin cement (Variolink II; A3 Yellow and transparent) specimens (thickness: 100 μm) were photocured under a ceramic block (2mm-thick; Base Dentine 0M1, Base Dentine 2M2 and Base Dentine 5M3) for 20 or 40 s. Specimen photocured without the ceramic block were used as control. Sixteen groups (n=3) were evaluated. Micro-ATR/FTIR spectrometry was used to evaluate the extent of polymerization of all sp after 24 h. The %DC was calculated and the data were analyzed using ANOVA 1-way and Tukey test ( =0,05). For the microtensile bond strength test, the occlusal dentin surface of eighty molars were exposed and etched with 37% phosphoric acid and an adhesive (Excite DSC) was applied. Eighty blocks (7.2 x 7.2 x 2.5 mm) of Base Dentine 0M1 and Base Dentine 5M3 of Vita VM7 ceramic were produced according to the manufacturers. The ceramic surface was etched with 10% hydrofluoric acid for 60 s, followed by the application of a silane agent and a dualcured resin cement (Variolink II; base and catalyst: A3 Yellow; base and catalyst: transparent), according to the manufacturers’ ...(Complete abstract click electronic access below)
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Tirala, David. "Testování a hodnocení vlastností keramických jader pro technologii vytavitelného modelu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-445169.
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Production of top quality castings for applications in energy, aerospace and medical industries by the addition of ceramic cores to investment casting presents many metallurgical and technological problems. Ceramic cores applied in investment casting are subjects to many requirements in terms of their inertness to the casted alloy and at the same time to their final removal from the casting cavity in such a way that does not damage the casting. Both of these assumptions can be achieved by applying a thin layer of inert oxide ceramic coating to the surface of a ceramic core, made out of a chemically removable – leachable oxide ceramic.
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Kinc, Marek. "Numerická simulace výroby keramických jader pro technologii lití na vytavitelný model." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231964.
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The aim of this diploma thesis is validation of numerical simulation of the ceramic core manufacturing in the investment casting proces. The first part submit the theoretical description of the manufacturing of the ceramic cores and a description of the basic principles of numerical simulations. The second part compares the video recording of filling the wax-ceramic mixture to the die-casting mold and simulation of the same process created in a simulation software Cadmould 3D-F.
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Rajala, Jonathan Watsell. "ELECTROSPINNING FABRICATION OF CERAMIC FIBERS FOR TRANSPARENT CONDUCTING AND HOLLOW TUBE MEMBRANE APPLICATIONS." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1480909959851349.
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Bořil, Petr. "Výroba a vlastnosti litých keramických jader na bázi etylsilikátu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319254.
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The aim of this diploma thesis is experimental verification of the influence of ceramics composition on the manipulation strength of the cores in the Shaw method. The work deals mainly with influence of the amount of acid in the composition of the binding fluid on the handling strength of the cores and the strength of the cores after annealing. The thesis further examines the possibility of increasing the handling strength of the cores by adding phosphoric acid to the binding fluid.
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Recchia, Johanna. "Le vase et le corps : archéologie du caractère anthropomorphe des poteries du Néolithique en Méditerranée nord-occidentale." Thesis, Montpellier 3, 2018. http://www.theses.fr/2018MON30081/document.
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L’étude du mobilier céramique des peuples de la Préhistoire récente permet aux archéologues de distinguer différents groupes culturels ou cultures matérielles. Ces variétés culturelles reposent sur l’adoption par des groupes humains d’un type particulier de vases qui varie dans le temps et dans l’espace dans les limites d’aires culturelles. Les décors, les éléments de préhension, la morphologie des vases, les techniques de fabrication déterminent ces styles. L’archéologue ou le céramologue perçoit dans l’abondance de caractères ou l’absence de ceux-ci, la marque, le signe, d’un fait culturel. Ces différents critères servent à établir une typologie qui permet d’attribuer une série céramique à un groupe culturel. À travers cette typologie, l’archéologue croit percevoir une intention culturelle. Cependant, un regard porté sur l’ensemble de la céramique du Néolithique affirmé voit, dans la poterie en elle-même, le marqueur d’une nouvelle représentation du fait social et culturel, qui accompagne le nouveau rapport entre l’homme et son environnement à partir du passage à l’économie de production. C’est au travers de la perception de l’identification du vase au corps humain, tel que l’on peut le percevoir dans les sociétés traditionnelles et dans quelques cultures archéologiques, que nous désirons dépasser les limites intrinsèques à l’analyse typologique. Les cultures matérielles sont multiples, séparées, divisées, et leur diversité ne matérialise pas seulement les variétés culturelles. La poterie est avant tout le marqueur d’un nouveau fait culturel qui concerne l’ensemble des cultures néolithiques. Elle est un des vecteurs qui cristallisent l’ancrage du Néolithique et avec lui, une nouvelle perception par l’homme de lui-même, de sa société, de l’univers réel qu’il habite, mais aussi de l’univers spirituel, mythologique, imaginé, symbolisé qui l’habitent. En choisissant comme point de départ les différentes démarches analytiques sur la céramique du Languedoc-Roussillon depuis le Néolithique ancien au Néolithique final, nous voulons considérer la poterie, au-delà de son intérêt matériel, dans son intérêt symbolique et culturelThis thesis proposes to study the question of the relations between the body and the Neolithic pottery through the case of so-called anthropomorphous vases in the north-western Mediterranean.The first part presents the problematic of this thesis and presents the chronological and geographical framework. We make a brief review of the knowledge of the presence of this type of artefacts and commonly proposed interpretations, and we expose the methods by which we intend to analyze anthropomorphic vases.The second part presents the corpus of vases collected in the catalog (volume 2) by chrono-cultural area. It proposes a typological classification of these pottery and it discusses more particularly the modalities of their emergence in the North-Western Mediterranean, their diffusion or their evolution.The last part questions the choice of pottery as a medium of Neolithic body representation. The creation of a repository of data from ethnology, ethnoarchaeology or narratives allows us to situate our object of study in the field of metaphor and to approach it as a sign. We draw inspiration from theories from semiology and more generally from cultural anthropology in order to get out of the usual accepted archaeological interpretations.The results lead us to propose a definition of anthropomorphic vases and to discuss the phenomenon of the anthropomorphization of vases in the Neolithic context and the effects of agro-pastoral lifestyles on the production of the body's imaginary
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Viat, Ariane. "Troisième corps à l'interface céramique métal sous chargement de fretting usure à hautes températures." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEC054.
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Dans un turboréacteur civil, le contact aube/disque de la turbine basse pression est soumis à un cyclage thermomécanique dû aux dilatations et déplacements différentiels des pièces pendant les phases de vol. Ce cyclage implique des micro-mouvements alternés relatifs, c’est-à-dire du fretting, à l’interface aube/disque. Le fretting à l’étude ici concerne un contact céramique-métal, en vue de comprendre le comportement tribologique des futures aubes revêtues de céramique en remplacement des pièces métalliques traditionnelles. Dans un premier temps, différents revêtements sont comparés vis-à-vis de leur tenue à l’usure par fretting à la température de fonctionnement des pièces (700°C). L’alliage métallique du contrecorps est celui du clinquant protégeant le disque, à savoir l’alliage base cobalt HS25. Pour le contact HS25/céramique le plus prometteur, le taux d’usure très bas ainsi que le faible frottement observés sont associés à la formation d’une glaze layer. La glaze layer est un troisième corps formé à partir des débris d’usure qui apparaît dans des contacts frottant à haute température. Traditionnellement observée pour des contacts métal/métal, sa formation pour un contact métal/céramique est nouvelle. La glaze layer est alors étudiée en détail. D’un point de vue tribologique, on établit sa cinétique et ses conditions de formation en température et en fonction des paramètres tribologiques, afin de garantir une usure faible en conditions de vol. D’un point de vue morphologique, la glaze layer est caractérisée comme étant un matériau nanostructuré amorphe et cristallin, formé à partir de débris à la fois métalliques et oxydés. Enfin, la glaze layer nanostructurée est associée à un comportement mécanique ductile dans son domaine de stabilité, alors que les débris sont fragiles en conditions d’usure forte. La corrélation des angles d’étude de la glaze layer permet alors de connaître les modalités de sa formation, en vue d’anticiper la protection d’un contact vis-à-vis de l’usure grâce à la création d’une glaze layerIn a civil turbojet motor, the blade/disk contact in the low pressure turbine undergoes thermomechanical cycling due to relative displacements between parts during the different flight phases. This cycling results in reciprocating micro-movements named “fretting” at the blade/disk interface. This study focuses on a ceramic versus metallic contact under fretting, aimed at describing the tribological behavior of developing ceramic-coated blades to replace phased-out metallic parts. Firstly, different ceramic coatings are compared regarding their wear resistance under fretting at in-flight temperature (700°C). The counterbody is the HS25 (cobalt-based alloy) protecting foil of the disk. The most favorable ceramic/metallic tribocouple evidences a very low wear rate as well as low friction that match the formation of a glaze layer. The glaze layer is a third body formed from wear debris in high temperature rubbed contacts. Such tribofilm has been commonly observed in metallic/metallic interfaces but its occurrence in a ceramic/metallic contact is new. Then the glaze layer is precisely characterized. Tribologically speaking, its kinetics and formation conditions are determined over temperature and tribological parameters, in order to ensure low wear under flight conditions. Morphologically, the glaze layer is a nanostructured amorphous and crystalline sintered from both metallic and oxidized worn debris. Finally, the nanostructured glaze layer is mechanically described as a ductile material in its stability domain, whereas debris from severe wear are brittle. The correlation of morphological, physico-chemical and mechanical studies enlighten the glaze layer formation criteria, with the aim of predicting glaze layer occurrence, hence wear protection for a given contact
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PORTELLA, KLEBER F. "Projeto, montagem e caracterizacao de um sensor de fluor com eletrolito solido ceramico de PbFsub2." reponame:Repositório Institucional do IPEN, 1997. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10645.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Park, Euisuk. "Dielectric and Strain Effects of Core-Shell / Barrier Layer Structures in Modified BaTiO3 Ceramics." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022602832.
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Brentel, Aline Scalone [UNESP]. "Efeito do sistema de acabamento e polimento na rugosidade superficial e formação in situ de biofilme dentário inicial em cerâmica feldspática micro-particulada." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/97336.
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brentel_as_me_sjc.pdf: 699454 bytes, checksum: be2fb21f3ef054302d8fc5241d84a0a5 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo do presente estudo foi avaliar uma cerâmica feldspática micro-particulada quanto à rugosidade superficial, hidrofobicidade e formação in situ do biofilme dentário. Amostras padronizadas da cerâmica foram confeccionadas e divididas em 4 grupos conforme o sistema de acabamento e polimento: glaze (G1); glaze e broca diamantada (G2); glaze, broca diamantada e pontas de borracha (G3); glaze, broca diamantada, ponta de borracha e disco de feltro impregnado com pasta diamantada (G4). Rugosidade foi avaliada antes e após os procedimentos de acabamento e polimento estabelecidos para cada grupo. O ângulo de contato da água deionizada foi avaliado em goniômetro. Dez pacientes usaram dispositivo bucal com amostras dos diferentes grupos durante 8 h. Decorrido o período experimental, o biofilme (n=10) foi analisado em microscopia confocal laser ( biovolume e espessura média) e microscopia eletrônica de varredura (MEV) (n=5). A rugosidade superficial foi significativamente diferente nos 4 grupos, sendo a ordem crescente de rugosidade G1 < G4 < G3 < G2. Em relação ao ângulo de contato, G1 apresentou a maior hidrofobicidade, não havendo diferenças entre os demais grupos. G1 e G4 foram semelhantes e apresentaram os menores valores de espessura média e biovolume do biofilme. G2 e G3 apresentaram os maiores valores de espessura média e biovolume sendo similares. Correlação positiva foi verificada entre rugosidade superficial e formação de biofilme in situ. As observações em MEV indicaram cocos isolados e diplococos em G1 com pouco material acelular. Em G2, presença de maior número de bactérias aderidas às amostras foi verificada. Em G3 foi verificado material fibrilar com cocos e bastonetes curtos constituindo colônias na superfície. Em G4, as amostras foram recobertas por material granular com poucos cocos isolados aderindo à superfície.
This study assessed the effect of different systems of finishing and polishing in a ceramic micro-particulate feldspatic, with respect, the surface roughness, hydrophobicity, topography and morphology analysis using SEM and analysis of biofilms, with respect to its thickness and its average biovolume using MCVL. Specimens (5mmX2mm), were distributed into four groups (n = 10) as, finishing and polishing used: G1: glaze; G2 - drill diamantada (KG Sorensen); G3 - diamantada drill and polishing with rubber tip (KG Sorensen); G4 - diamantada drill and polishing with rubber tip followed by pulp diamantada with disc of felt. Rugosidade was evaluated in rugosímetro (Surftest SJ-301, Mitutoyo) before and after applying the glaze. The hydrophobicity was evaluated by a goniometer (Ramé-Hart - DROPimage, Advanced, USA) Ten patients used a device with the samples for 8h, then they were tested in MCVL. Topography and the morphology were evaluated in SEM. The roughness Ra (μm), biovolume and thickness of the biofilm and were analyzed using ANOVA and Tukey. There was no significant difference with respect to the amount of biovolume factor and the average thickness of biofilm between G2 and G3 and between G1 and G4. G1 and G4, were more hydrophobicity, with respect to G2, G3. There are correlated with roughness and formation of biofilms. There is the possibility of hydrophobicity is linked to lower bacterial adherence.
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Forberger, Virag Nicole. "Influence of the type of post and core on in vitro marginal continuity, fracture resistance, and fracture mode of lithia disilicate-based all-ceramic crowns /." [S.l.] : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000278509.
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Zhou, Lei. "Processing Effects on Core-Shell Grain Formation in ZrO2 Modified BaTiO3 Ceramics." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin983977793.
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Moreno, Marina Barrêto Pereira 1989. "Efeito de diferentes cores e do tempo pós-fotoativação na dureza Knoop do cimento resinoso = Effect of different shades and post-activation times on Knoop hardness of resin cement." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289558.
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Orientador: Lourenço Correr SobrinhoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: A polimerização adequada de cimentos resinosos é fundamental para obter excelentes propriedades físico-mecânicas. Fatores relacionados à cerâmica e ao próprio cimento podem influenciar a passagem de luz, reduzindo a fotoativação e alterando o grau de polimerização dos cimentos. O propósito neste estudo foi avaliar a dureza Knoop após 15 min ou 24h de diferentes cores de cimento resinoso fotoativado, com ou sem a interposição da cerâmica, em diferentes profundidades. Amostras com 5 mm de diâmetro e 1 mm de espessura do cimento resinoso Variolink Veneer (Ivoclar Vivadent) nas cores HV+1, HV+2, HV+3, MV0, LV-1, LV-2 e LV-3, foram feitas em um molde de elastômero, cobertas com uma tira de poliéster e por um disco de cerâmica IPS e.max Press (Ivoclar Vivadent) na espessura de 0,7 mm e fotoativadas por 20 segundos usando o LED Radii-cal (SDI Limited), com 1.200 mW/cm2. O cimento resinoso foi transversalmente desgastado e submetido ao teste de dureza Knoop usando o aparelho HMV 2 (Shimadzu), com carga de 50g aplicada por 15 segundos, 15 min após a fotoativação e após armazenagem a 37o C por 24 horas. Cinco penetrações foram feitas na secção transversal a 100 e 700 µm da superfície de topo, sendo que vinte amostras foram confeccionadas para cada cor do cimento resinoso Variolink Veneer em cada período de armazenagem. Os dados foram submetidos à Análise de Variância em esquema de parcelas subdivididas (cor, tempo pós-ativação, modo de ativação e profundidade), seguido pelo teste de Tukey post hoc (? = 0,05). Significante diferença para a cor (p<0,0001), modo de ativação (p<0,001), tempo pós-ativação (p<0,0001) e profundidade (p<0,0001) foi detectada. Nenhuma diferença significante foi detectada entre as interações (p>0,05), exceto para a interação cor x tempo pós-ativação (p<0,0045) e modo de ativação x tempo pós-ativação (p<0,0003). A cor do cimento resinoso e a ativação indireta tiveram significante efeito na dureza Knoop. Houve um aumento significante na dureza Knoop, após 24 horas para todas as cores do cimento resinoso. A profundidade influenciou significantemente na dureza Knoop
Abstract: An adequate polymerization of resin cements is essential to obtain excellent physical and mechanical properties. Factors related to the ceramic and cement itself can influence the passage of light, decreasing the light curing and the degree of polymerization of the cement. The aim of this study was to evaluate the Knoop hardness number of different shades of resin cement light-cured either through or without the ceramic restoration and tested after 15 min or 24 h at different depths. The specimens with 5.0 mm in diameter and 1.0 mm thickness of the luting resin cement Variolink Veneer (Ivoclar Vivadent) in the HV+1, HV+2, HV+3, MV0, LV-1, LV-2 and LV-3 shades, were made in the elastomer mold, covered with a mylar strip and ceramic IPS e.max Press (Ivoclar Vivadent) disc in the thickness 0.7 mm and light-activated for 20 seconds using a LED Radii-cal (SDI Limited), with 1200 mW/cm2. The resin cement specimens were transversely wet-flattened and submitted to Knoop hardness using HMV 2 microhardness tester (Shimadzu), with a load of 50g applied for 15 seconds, 15 min after photoactivation and after storage at 37o C for 24 hours. Five indentations were made in the cross-sectional area at 100 and 700 µm from the top surface, being that twenty specimens were made for each shades of Variolink Veneer in each stored time. Data were submitted to ANOVA split-plot design (shade, post-cure time, mode of activation, and depth), followed by Tukey post hoc test (? = 0.05). The mean values of Knoop hardness are shown in Table 1. Significant differences for shade (p<0.0001), mode of activation (p<0.001), post-cure time (p<0.0001) and depth (p<0.0001) were detected. There was not significance in the interactions (p>0.05), except for shade x post-cure time (p<0.0045) and mode of activation x post-cure time (p<0.0003). The resin cement shade and indirect activation had a significant effect on the Knoop hardness. There was a significant increase in Knoop hardness after 24 h in all cements shades. The depth influenced significantly on the Knoop hardness
Mestrado
Materiais Dentarios
Mestra em Materiais Dentários
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Brentel, Aline Scalone. "Efeito do sistema de acabamento e polimento na rugosidade superficial e formação in situ de biofilme dentário inicial em cerâmica feldspática micro-particulada /." São José dos campos : [s.n.], 2008. http://hdl.handle.net/11449/97336.
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Resumo: O objetivo do presente estudo foi avaliar uma cerâmica feldspática micro-particulada quanto à rugosidade superficial, hidrofobicidade e formação in situ do biofilme dentário. Amostras padronizadas da cerâmica foram confeccionadas e divididas em 4 grupos conforme o sistema de acabamento e polimento: glaze (G1); glaze e broca diamantada (G2); glaze, broca diamantada e pontas de borracha (G3); glaze, broca diamantada, ponta de borracha e disco de feltro impregnado com pasta diamantada (G4). Rugosidade foi avaliada antes e após os procedimentos de acabamento e polimento estabelecidos para cada grupo. O ângulo de contato da água deionizada foi avaliado em goniômetro. Dez pacientes usaram dispositivo bucal com amostras dos diferentes grupos durante 8 h. Decorrido o período experimental, o biofilme (n=10) foi analisado em microscopia confocal laser ( biovolume e espessura média) e microscopia eletrônica de varredura (MEV) (n=5). A rugosidade superficial foi significativamente diferente nos 4 grupos, sendo a ordem crescente de rugosidade G1 < G4 < G3 < G2. Em relação ao ângulo de contato, G1 apresentou a maior hidrofobicidade, não havendo diferenças entre os demais grupos. G1 e G4 foram semelhantes e apresentaram os menores valores de espessura média e biovolume do biofilme. G2 e G3 apresentaram os maiores valores de espessura média e biovolume sendo similares. Correlação positiva foi verificada entre rugosidade superficial e formação de biofilme in situ. As observações em MEV indicaram cocos isolados e diplococos em G1 com pouco material acelular. Em G2, presença de maior número de bactérias aderidas às amostras foi verificada. Em G3 foi verificado material fibrilar com cocos e bastonetes curtos constituindo colônias na superfície. Em G4, as amostras foram recobertas por material granular com poucos cocos isolados aderindo à superfície.Abstract: This study assessed the effect of different systems of finishing and polishing in a ceramic micro-particulate feldspatic, with respect, the surface roughness, hydrophobicity, topography and morphology analysis using SEM and analysis of biofilms, with respect to its thickness and its average biovolume using MCVL. Specimens (5mmX2mm), were distributed into four groups (n = 10) as, finishing and polishing used: G1: glaze; G2 - drill diamantada (KG Sorensen); G3 - diamantada drill and polishing with rubber tip (KG Sorensen); G4 - diamantada drill and polishing with rubber tip followed by pulp diamantada with disc of felt. Rugosidade was evaluated in rugosímetro (Surftest SJ-301, Mitutoyo) before and after applying the glaze. The hydrophobicity was evaluated by a goniometer (Ramé-Hart - DROPimage, Advanced, USA) Ten patients used a device with the samples for 8h, then they were tested in MCVL. Topography and the morphology were evaluated in SEM. The roughness Ra (μm), biovolume and thickness of the biofilm and were analyzed using ANOVA and Tukey. There was no significant difference with respect to the amount of biovolume factor and the average thickness of biofilm between G2 and G3 and between G1 and G4. G1 and G4, were more hydrophobicity, with respect to G2, G3. There are correlated with roughness and formation of biofilms. There is the possibility of hydrophobicity is linked to lower bacterial adherence.
Orientador: Marco Antonio Bottino
Coorientador: Antonio Olavo Cardoso Jorge
Banca: Marco Antonio Bottino
Banca: Regina Maria Puppin Rontani
Banca: Carlos Augusto Pavanelli
Mestre
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Kaštyl, Jaroslav. "Vrstevnaté keramiky připravené metodou termoplastické koextruze." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234577.
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In the doctoral thesis, the bi-layer ceramic bodies with core-shell geometry were prepared by thermoplastic co-extrusion method and for these composite bodies the mechanical properties were studied. For study of co-extrusion and mechanical properties were designed two composite systems. First system ZTA-A combined the dense core ZTA (zirconia-toughened alumina) and the dense shell Al2O3. Second system ZST-Z consisted of porous core and dense shell made from ZrO2 for both cases. In the thesis, the rheology of ceramic thermoplastic suspensions and their mutual influence during co-extrusion was studied. Subsequently, the debinding process and sintering were studied, and based on the optimization of all process steps were obtained defect-free bodies with core-shell geometry. The mechanical properties (elastic modulus, hardness and bending strength) were determined for sintered bodies. To estimate the stress path in the core shell bodies loaded in bending, the relationship considering different elastic moduli of the core and the shell was used. For bodies of ZTA-A system was increased the strength in comparison with monolithic bodies of the individual components. Thus, bodies with high surface hardness of shell from Al2O3 and moreover having high fracture strength in bending were obtained. The effective elastic modulus was decreased for bodies of ZST-Z system up to 25 % in comparison with the elastic modulus of dense monolithic samples. The same effective modulus of elasticity was possible to achieve with core-shell bodies while maintaining significantly higher fracture strength than monolithic porous bodies or pipes.
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Heyl, Hanna Verena. "Phase Relations in the YBa2Cu3O7-x - SiO2 System and the Impact on Superconducting Fibers." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/95058.
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This dissertation presents the first reported identification and analyses of the phase relations in the YBa2Cu3O7-x (YBCO)-SiO2 system at elevated temperatures. In this regard, a rigorous characterization study of the reaction phases within YBCO glass fibers, heat-treated YBCO+SiO2 pellets, rapid thermally annealed YBCO+SiO2 rods and rapid thermally annealed YBCO powder inside a fused silica tube is provided. These analyses are based on a vast set of generated novel results obtained using energy dispersive spectroscopy analyses on an environmental scanning electron microscope, X-Ray diffraction analyses, Raman spectroscopy, X-ray photoelectron spectroscopy analyses and a cross-polarized light study.
First, original drawings of YBCO into glass fibers using the molten-core approach on a fiber draw tower in air and oxygen atmospheres are presented and analyzed. The performed analyses reveal the occurrence of reactions between the YBCO core and the silica cladding in as-drawn fibers as well as after additional heat-treatments. A detailed analysis and characterization of the occurring dissolution and diffusion based reaction processes is, then, provided along with the identification of the arising phase separation. Moreover, in order to analyze drawing YBCO glass fibers at lower temperatures, the use of borosilicate as the preform material is also investigated.
This varied set of experiments and associated analyses reveal that the as-drawn YBCO fibers contain an amorphous core and that cuprite (Cu2O) is the first phase to crystallize out of the amorphous silicate matrix upon heat-treatment. Furthermore, the obtained results demonstrate the dissolution of the fused silica cladding into Si4+ and O2- ions and their subsequent diffusion into the molten YBCO core, leading to phase separation due to an occurring miscibility gap in the YBCO-SiO2 system as well as to silicate formation and amorphization of the YBCO core. This, as a result, prohibits the formation of the superconductive YBCO (Y-123) phase upon annealing. In addition, heat-treatment analyses show that higher temperatures or prolonged dwelling times at lower temperatures lead to the formation of barium copper and yttrium barium silicates. The analysis focusing on the use of borosilicate as the preform material reveals that drawing at lower temperatures reduces the dissolution and diffusion based reactions, but does not prevent them. Furthermore, the analysis on YBCO glass fibers with a fused silica cladding drawn in oxygen atmosphere shows that a higher oxygen content increases the dissolution of the fused silica cladding into its ions and their subsequent diffusion into the molten YBCO core.
In addition, the performed heat-treatments on YBCO+SiO2 pellets in air and oxygen atmospheres demonstrate the gradual decomposition of the Y-123 phase with an increase in SiO2 content. Moreover, the rapid thermal annealing experiments with a subsequent quenching step on YBCO+SiO2 rods and on YBCO powder inserted inside a fused silica tube show the decomposition of the Y-123 phase and the formation of phases similar to the phases obtained in the YBCO glass fiber study, thus corroborating the results thereof.
In summary, this dissertation enables the determination of the phase relations and reaction processes within the YBCO-SiO2 system, the identification of the direct effects of the silicon content on the Y-123 phase decomposition, as well as a rigorous characterization of the dissolution and diffusion based reactions within the YBCO-SiO2 glass-clad fiber system. The generated results and drawn conclusions build a fundamental understanding of phase relations in the YBCO-SiO2 system, which enables a definite assessment of the feasibility of manufacturing long-scale purely superconductive YBCO glass fibers using the molten-core approach and introduces advanced contributions to general glass-clad fiber systems manufactured using this method.Doctor of Philosophy
This dissertation provides the first reported identification and analysis of the phase relations in the YBa2Cu3O7-x (YBCO)-SiO2 system at high temperatures. In this regard, a thorough characterization study of the reaction phases within YBCO glass fibers drawn using the molten-core approach on a fiber draw tower is provided. In addition, heat-treatment analyses considering YBCO+SiO2 pellets, rapid thermally annealed YBCO+SiO2 rods and rapid thermally annealed YBCO powder inside a fused silica tube are performed to gain further fundamental insights. The performed analyses are based on a wide set of characterization methods including energy dispersive spectroscopy on an environmental scanning electron microscope, X-Ray diffraction analyses, Raman spectroscopy, X-ray photoelectron spectroscopy and a cross-polarized light study. Our experimental results and performed analyses identify the phase relations and reaction processes within the YBCO-SiO2 system at elevated temperatures, demonstrate the direct effects of the silicon content on the superconductive YBCO phase decomposition, enable drawing definite conclusions regarding the feasibility of manufacturing long-scale purely superconductive YBCO glass fibers using the molten-core approach, and, characterize the dissolution and diffusion based reactions occurring within the YBCO-SiO2 glass-clad fiber system. In a nutshell, this dissertation provides a fundamental understanding of phase relations in the YBCO-SiO2 glass-clad system as well as key insights covering general glass-clad fibers drawn using the molten-core approach, paving the way for improved glass-clad fiber manufacturing using this method.
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Bhandavat, Romil. "Molecular precursor derived SiBCN/CNT and SiOC/CNT composite nanowires for energy based applications." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/15347.
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Doctor of PhilosophyDepartment of Mechanical and Nuclear Engineering
Gurpreet Singh
Molecular precursor derived ceramics (also known as polymer-derived ceramics or PDCs) are high temperature glasses that have been studied for applications involving operation at elevated temperatures. Prepared from controlled thermal degradation of liquid-phase organosilicon precursors, these ceramics offer remarkable engineering properties such as resistance to crystallization up to 1400 °C, semiconductor behavior at high temperatures and intense photoluminescence. These properties are a direct result of their covalent bonded amorphous network and free (-sp2) carbon along with mixed Si/B/C/N/O bonds, which otherwise can not be obtained through conventional ceramic processing techniques. This thesis demonstrates synthesis of a unique core/shell type nanowire structure involving either siliconboroncarbonitride (SiBCN) or siliconoxycarbide (SiOC) as the shell with carbon nanotube (CNT) acting as the core. This was made possible by liquid phase functionalization of CNT surfaces with respective polymeric precursor (e.g., home-made boron-modified polyureamethylvinylsilazane for SiBCN/CNT and commercially obtained polysiloxane for SiOC/CNT), followed by controlled pyrolysis in inert conditions. This unique architecture has several benefits such as high temperature oxidation resistance (provided by the ceramic shell), improved electrical conductivity and mechanical toughness (attributed to the CNT core) that allowed us to explore its use in energy conversion and storage devices. The first application involved use of SiBCN/CNT composite as a high temperature radiation absorbant material for laser thermal calorimeter. SiBCN/CNT spray coatings on copper substrate were exposed to high energy laser beams (continuous wave at 10.6 μm, 2.5 kW CO2 laser, 10 seconds) and resulting change in its microstructure was studied ex-situ. With the aid of multiple techniques we ascertained the thermal damage resistance to be 15 kW/cm2 with optical absorbance exceeding 97 %. This represents one order of magnitude improvement over bare CNTs (1.4 kW/cm2) coatings and two orders of magnitude over the conventional carbon paint (0.1 kW/cm2) currently in use. The second application involved use of SiBCN/CNT and SiOC/CNT composite coatings as energy storage (anode) material in a Li-ion rechargeable battery. Anode coatings (~1mg/cm2) prepared using SiBCN/CNT synthesized at 1100 °C exhibited high reversible (useable) capacity of 412 mAh/g even after 30 cycles. Further improvement in reversible capacity was obtained for SiOC/CNT coatings with 686 mAh/g at 40 cycles and approximately 99.6 % cyclic efficiency. Further, post cycling imaging of dissembled cells indicated good mechanical stability of these anodes and formation of a stable passivating layer necessary for long term cycling of the cell. This improved performance was collectively attributed to the amorphous ceramic shell that offered Li storage sites and the CNT core that provided the required mechanical strength against volume changes associated with repeated Li-cycling. This novel approach for synthesis of PDC nanocomposites and its application based testing offers a starting point to carry out further research with a variety of PDC chemistries at both fundamental and applied levels.
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Chen, Yi. "The redefined centre, periphery and margin : the long-term interaction sphere of southern China 3000-221 BC." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:0ae8b337-7a65-427d-9a37-9be7f4d17f9c.
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This thesis investigates southern China as a part of dynamic and extensive interregional networks from the third to the first millennium BC and explores the changing roles of different southern regions within the interregional relationships. This was an important transitional period for southern China as it was the time when several prominent and farreaching innovations of technologies and material culture were made or adopted in the area. Four key sets of materials – rice, bronze, ceramics and jade – are examined with a World-system perspective to reveal interregional contacts in different directions and of different nature between southern China and a number of neighbouring regions. By stressing on local responses towards different technologies and material culture in different period, an alternative narrative to that stemmed from Chinese historiography is, therefore, suggested. Instead of being a passive and 'backward' periphery in the traditional sense, southern China presents diversification of material culture over time. Many of the mechanisms of transmission and circulation in the south are characterised by 'leaked' technologies and designs, as well as 'selective adoption' and local redevelopment of material culture.
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Pêche-Quilichini, Kewin. "Bols, paniers et grains de riz : Formes et décors de vaisselles céramiques du Bronze final et du premier âge du fer de Corse." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10194/document.
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La masse de documentation céramique disponible pour les différentes phases de la Protohistoire corse était aussi quantitativement importante que peu étudiée. L’analyse de ces sources (43 collections issues de 35 sites) selon une méthodologie basée sur les rapports de proportion, couplée au réexamen critique des publications et des datations radiocarbone, engendre une vision renouvelée de la structure chrono-culturelle des groupes insulaires entre Bronze final et premier âge du Fer. Pour aboutir, par sériation et périodisation, à un schéma reposant sur une articulation entre des entités matérielles clairement définies, il a notamment fallu se détacher de certains faux problèmes à l’origine d’hypothèses initiales souvent arbitraires ou trop tranchées. Les principaux résultats font apparaître une structuration polygénique complexe des assemblages céramiques, subtil jeu d’équilibre entre tradition, emprunt et innovation en fonction des époques et des contextes, mais qui intègre pleinement la Corse dans les dynamiques tyrrhéniennes et méditerranéennes à l’aube de l’avènement des premières sociétés historiquesThe amount of information available on ceramic ware from the different phases of Corsican protohistory is as quantitatively important as little studied. An analysis of these sources (43 collections from 35 sites) using a methodology based on ratios of proportion, as well as a critical re-examination of publications and radiocarbon dates, brings about a new understanding of the chrono-cultural structure of island groups between the Late Bronze and the Early Iron Ages. After resolving a few of the issues which led to previous arbitrary and incomplete analyses, it has been possible to generate a schema based on clearly defined material elements using seriation and periodisation. The main results show a complex polygenic structure in the ceramic assemblages, a subtle game of balance between tradition, borrowing and innovation in relationship to periods and contexts that plainly integrates Corsica in Tyrrhenian and Mediterranean dynamics at the dawn of the first historic societies
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Carlini, Elaine Carina. "Estudo sobre a expansão térmica linear das areias de fundição e a sua influência sobre as propriedades a quente dos machos." Universidade do Estado de Santa Catarina, 2011. http://tede.udesc.br/handle/handle/1794.
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Previous issue date: 2011-07-26Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This paper presents a study on the linear thermal expansion of foundry sands used as aggregates in foundry cores with resin phenolic-urethane/Cold Box. The work examines the correlation between thermal expansion of the sand and hot deformation tendency of the core during the casting process. The hot deformation tendency has important technological significance, because it affects the dimensional quality of the casting. It was tested three silica sands, one chromite sand, two types of based aluminum silicates sands and two types of blended minerals. The sands were characterized for particle size distribution, loss on ignition, AFS clay content, density, permeability, pH, acid demand, specific surface area, coefficient of angularity, chemical analysis, XRD, shape and surface of the grains and linear thermal expansion. The dilatometer test was done with loose unbonded sands. The sand was placed into an alumina sample holder and inserted into the dilatometer. The hot deformation tendency of the core was performed with two tests: first, using an experimental iron casting and second a hot distortion laboratory test, in which the test specimen was subjected to heating by a flame. It was verified that the hot deformation tendency is directly correlated to the thermal expansion of the sand. The higher the thermal expansion of the sand used to make cores the more susceptible it is to hot deformation.
O presente trabalho apresenta um estudo sobre a influência da expansão térmica linear das areias de fundição utilizadas para a confecção de machos com resina fenólicauretânica/ Cold Box sobre a tendência à deformação a quente dos machos durante o processo de fundição das peças. A tendência à deformação a quente dos machos tem grande importância tecnológica, porque isto afeta diretamente a qualidade dimensional das peças fundidas. Foram ensaiadas três areias de sílica, uma areia de cromita, duas areias à base de silicato de alumínio, dois compostos de minerais. As areias foram caracterizadas quanto à distribuição granulométrica, perda ao fogo, teor de argila AFS, densidades solta e relativa, permeabilidade, pH, demanda ácida, superfície específica, coeficiente de angularidade, análise química, difratometria de raios-X, formato e superfície dos grãos e expansão térmica linear. O ensaio de dilatometria das areias foi realizado em corpos de provas não ligados com aglomerantes, ou seja, a areia foi acondicionada em um porta-amostra de alumina e este foi inserido no dilatômetro. Foram executados dois ensaios de tendência à deformação a quente dos machos: o ensaio de corpo de prova fundido e o ensaio de distorção a quente em laboratório, onde o corpo de prova (macho) é submetido a um aquecimento por chama. Verificou-se que a tendência à deformação a quente dos machos tem correlação direta com a expansão térmica da areia. Quanto maior a expansão térmica da areia utilizada para a confecção do macho mais suscetível ele estará à deformação a quente.
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Nunes, Francine Machado. "Produção e caracterização da cerâmica vermelha com a adição de resíduos oriundos da lavagem da lã de ovinos." Universidade Federal do Pampa, 2016. http://dspace.unipampa.edu.br:8080/xmlui/handle/riu/1262.
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A utilização de cinzas de resíduos sólidos para a fabricação de produtos cerâmicos tem apresentado evidências a fim de melhorar as propriedades químicas, físicas e mecânicas, minimizar os problemas ambientais e reduzir o volume de extração de matéria-prima argilosa. Em vista disso, o presente trabalho tem como objetivo avaliar a possibilidade de fabricar produtos cerâmicos a base de argila mais a adição de cinza de resíduo de lã de ovinos em diferentes percentuais, tendo por finalidade a aplicação na construção civil. O resíduo é proveniente do processo de beneficiamento da lã de ovinos em uma indústria têxtil, sendo que este foi queimado ao ar livre e peneirado em um conjunto de peneiras 20, 30, 40, 60 e 80 mesh. Foram realizadas formulações contendo apenas argila in natura e com adições de cinza de lã (CL) em percentagens de 5, 10, 20 e 30 % na massa de cerâmica vermelha, sendo submetidas à caracterização química pela Fluorescência de Raios-X (FRX) e Espectroscopia de Absorção na Região do Infravermelho com Transformada de Fourier (FT-IR); mineralógica com Difração de Raios-X (DRX); térmica pela Análise Termogravimétrica (TG) e Calorimetria Exploratória Diferencial (DSC); e física por meio da distribuição granulométrica e índices físicos. A conformação das amostras foi realizada por prensagem e extrusão à vácuo. E as contrações lineares de secagem e de sinterização, também foram avaliadas. A sinterização dos produtos cerâmicos foi realizada em temperaturas de 600, 700 e 800 °C, com taxa de aquecimento de 100 °Cmin-1 e patamar de sinterização de três horas. As propriedades estruturais dos produtos foram realizadas por meio de FT-IR e DRX, e a resistência mecânica pela tensão de ruptura à flexão. Outras análises físicas como contrações lineares de secagem, porosidade aparente, massa específica aparente e absorção de água, também foram avaliadas. Para a resistência mecânica a média dos valores obtidos variou de 0,38 ± 0,15 MPa a 6,70 ± 0,76 MPa, e para absorção de água, a média dos valores foi de 14,72 ± 0,39 % a 27,60 ± 1,05 %, para os produtos cerâmicos prensados. A avaliação destes mesmos parâmetros para os produtos cerâmicos extrudados, apresentou variação de 2,38 ± 1,47 MPa a 7,38 ± 3,00 MPa e de 8,57 ± 0,68 % a 24,80 ± 1,08 %. A resistência mecânica e absorção de água obtiveram melhores valores na temperatura de queima a 800 °C. No entanto, os valores encontrados foram abaixo do esperado devido aos produtos cerâmicos extrudados apresentar patologias como o “coração negro”.
The use of solid ash residue for the manufacture of ceramic products has been evidence to improve the chemical, physical and mechanical properties, minimizing environmental problems and reduce the volume of extraction clayey raw materials. In view of this, the present study aims to evaluate the possibility to make ceramics by the clay added by sheep wool waste ash, in different percentages. The purpose of this application is the construction bricks. The residue is derived from the beneficiation process of the sheep wool into a textile, and this was burnt at the air and sieved in a set of sieves 20, 30, 40, 60 and 80 mesh, only formulations were made containing clay and wool gray additions (CL) in percentages of 5, 10, 20 and 30 % in a red ceramic, being subjected to chemical characterization by X-Ray Fluorescence (XRF) and Fourier Transform in the Infrared Spectroscopy (FT-IR); Mineralogical with X-Ray Diffraction (XRD); Thermal by Thermogravimetric Analysis (TG) and Differential Scanning Calorimetry (DSC); through of physical and particle size distribution and physical indexes. The conformation of the samples was accomplished by pressing and vacuum extrusion. And the linear shrinkage by drying and heating, were also evaluated. The sintering of the ceramic products is performed at temperatures of 600, 700 and 800 °C with a the rate of 100 °Cmin -1 and three hours burning level. The structural properties of the products were performed by FT-IR and XRD, and the mechanical strength of the flexural breaking strain. Other physical analysis such as linear shrinkage drying, porosity, bulk density and water absorption were also evaluated. For mechanical strength average values obtained ranged from 0.38 ± 0.15 MPa to 6.70 ± 0.76 MPa and water absorption, the average value was 14.72 ± 0.39 % and 27.60 ± 1.05 % for the ceramics pressed. The evaluation of these same parameters for extruded ceramics, changed from 2.38 ± 1.47 MPa to 7.38 ± 3.00 MPa and 8.57 ± 0.68 % to 24.80 ± 1.08 %. The mechanical strength and water absorption values obtained in the best heating temperature to 800 °C. However, the values were lower than expected due to the extruded ceramic products present conditions as the “black core”.
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Šmíd, Václav. "Bytový dům, Brno - Židenice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227633.
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Within the frame of my master's thesis I processed a project documentation for a construction of an apartment house in Brno – Židenice. The building is unattached and has 7 floors. On the ground floor there are four individual garages, cellar cubicles and a utility room. There are apartments on all other floors. On the highest floor, there is situated a singular apartment with outdoor terrace and vegetation area. The building is founded on strips made of reinforced concrete, vertical load-bearing structure is made of cermic blocks, floor structure is made of hollow core slabs and staircase is also made of prefabricated elements. The house is insulated with contact thermal insulation made of mineral wool. During the process of creating the projet, I followed all the requirements of actual regulations and legal enactments, to provide sufficient mechanical endurance and stability, health safety of the inner space as well as safety of the natural environment.
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Kudinova, Maryna. "Développement de nouvelles matrices vitreuses pour la fonctionnalisation de fibres optiques par l’exploitation de la technologie Poudre." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0124/document.
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La majeure partie des fibres optiques utilisées dans les domaines des sources optiques et des capteurs sont dites 'fonctionnalisées', c'est à dire qu'elles possèdent des propriétés nouvelles, de par leur nature et/ou leur structure, par rapport aux fibres standards. Pour ce faire, nous allons exploiter la technologie 'Poudre' pour la réalisation de fibres optiques utilisant les propriétés de matrices vitreuses originales développées lors de cette thèse. Trois familles de fibres seront étudier afin de démontrer le fort potentiel de cette association, matériaux – technologie. La première exploitera la structuration de la gaine optique à l'aide de deux barreaux de verre vitreux (type Panda), dopés ou non à l'aide d'oxyde de cuivre. L'étude de cette fibre sera faite depuis la synthèse du matériau jusqu'au test de cette fibre en tant que capteur. La seconde fibre nous amènera à concevoir un verre optique inédit à ce jour, à définir la composition optimale et la décliner sous forme d'une fibre optique incluant ce verre pour le cœur. Enfin le procédé de fabrication de fibres optiques sera utilisé pour réaliser de premières fibres optiques à cœur vitrocéramique, c'est à dire partant d'une matrice vitreuse spécialement développée pour cette application arriver à faire croitre les nanostructures dans le cœur de la fibre et obtenir ainsi une famille de fibre inéditeThe main part of optical fibers used in the fields of optical sources and sensors are called 'functionalised', i.e. they have new properties, due to their nature and/or structure, compared to standard fibers. To do this, we will use 'Powder' technology for the realization of optical fiber using properties of original vitreous glasses developed during this thesis. Three families of optical fibers will be studied in order to demonstrate the great potential of this association, materials - technology. The first exploit the structuring of the cladding with two vitreous glass rods (Panda type) doped or not with copper oxide. The study of this fiber is done from the synthesis of the material up to the test of this fiber as a sensor. The second fiber leads us to design a novel optical glass matrix, to define the optimal composition and decline form of an optical fiber including the glass for the core. Finally, the optical fiber manufacturing process is used to produce optical fiber with glass-ceramic core, i.e. starting from a vitreous matrix specially developed for this application happen to grow the nano-structures in the core of the fiber and obtain a novel fiber family
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Váňa, Jan. "Hotel s posilovnou." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-396161.
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The subject of the diploma thesis is new stand-alone hotel with a catering service and a relaxation zone including a fitness room, a table tennis room, massages and a solarium. The individual functional parts are separated and can be operated independently of each other. The Building consists of three floors. The ground floor will serve to run a restaurant with a background and a for relaxation zone, the remaining two floors will be used to accommodate guests and the necessary facilities. The maximum capacity for the accommodation is 59 people and requires four employees to operate it. The restaurant is designed for 81 guests and a total of 7 employees. The relaxation part is for guests only and is not accessible to other people. The structure is based on strip foundations from plain concrete and reinforced concrete foundation footing. Peripheral vertical load-bearing structures of the first above-ground floor are designed from permanent formwork system, all others loadbearing walls will be walled-up from vertically perforated block laid on thin-film adhesive. The floor structures are designed as an assembly of prestressed hollow core slabs. Roofing of the building will be made as a flat vegetation roof.
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Benhadjala, Warda. "Fiabilité et miniaturisation des condensateurs pour l'aéronautique : de l'évaluation de composants céramique de puissance à l'étude de nanoparticules hybrides céramique / polymère pour technologies enterrées." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR15271/document.
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L’amélioration des systèmes électroniques pour le déploiement de l'avion tout électrique dépend de la capacité des composants passifs, tels que les condensateurs, à réduire leur volume, leur masse et leur coût, et augmenter leurs performances et leur fiabilité, particulièrement dans l’environnement aéronautique. Dans ce contexte, cette thèse a eu pour objectif l’étude et le développement de nouvelles technologies de condensateurs pour des applications avioniques. Dans la première partie des travaux, nous abordons l’évaluation de condensateurs céramique de puissance. La technologie céramique constitue, en effet, l’une des rares solutions matures capables de répondre aux exigences des équipementiers. La caractérisation, l’analyse des mécanismes de défaillance, de leurs effets et de leur criticité (AMDEC) ainsi que l’étude de fiabilité et de robustesse de composants commerciaux présentant des architectures originales (condensateurs multi-chips) ont été réalisées. Ces résultats ont été complétés par une étude plus amont sur la caractérisation de céramiques frittées par frittage flash (SPS). Les permittivités colossales de ces matériaux permettraient d’accroitre la fiabilité et la miniaturisation des condensateurs tout en conservant de fortes valeurs de capacité et de tension nominale. La seconde partie, plus fondamentale, a été consacrée au développement de nanoparticules céramique/polymère coeur-écorce pour des applications de condensateurs enterrés, opérant aux radiofréquences. La synthèse et les caractérisations physico-chimiques des nanocomposites ainsi que les procédés de fabrication de condensateurs en couches épaisses sont, en premier lieu, décrits. Une méthode de caractérisation électrique large bande a été mise au point pour permettre l’analyse des propriétés diélectriques et des mécanismes de conduction des nanoparticules. Les performances des dispositifs ont été recherchées en fonction de la température et des procédés de mise en forme. En outre, la durabilité en température de ces derniers a été évaluéeThe improvement of electronic systems for the deployment of all-electric aircrafts depends on the ability of passive components, such as capacitors, to reduce their volume, weight and cost, and to increase their performance and reliability, particularly in the aeronautical environment. In this context, the objective of this thesis was to study and develop novel capacitor technologies for avionics. In the first part of this work, the evaluation of power ceramic capacitors has been discussed. Indeed, the ceramic technology appeared to be one of the few mature solutions meeting the requirements of OEMs. The characterization, the failure mode, effects and criticality analysis (FMECA) and reliability and robustness assessment of commercial components using original architectures (multi-chip capacitors) have been performed. These results have been completed by a more advanced study on the characterization of new ceramics sintered by spark plasma sintering (SPS). The colossal permittivity of these materials could allow to increase reliability and miniaturization of capacitors while maintaining high values of capacitance and voltage rating. The second part, more fundamental, is devoted to the development of core-shell ceramic/polymer nanoparticles for embedded capacitors operating at radiofrequencies. The synthesis and the physicochemical characterization of the nanocomposites as well as the manufacturing processes of the thick film capacitors are first described. A new broadband electrical characterization methodology has been developed to analyze the dielectric properties and the conduction mechanisms of the nanoparticles. The effects of the temperature and the manufacturing process on the device performance have been investigated. In addition, the durability was evaluated
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Králíková, Zuzana. "Základní škola." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227161.
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Diploma thesis solves the design of the elementary school. The building is situated in Letohrad in region Pardubice. The design of the school building contains small sport hall for pupils and for possible public access. Dinning room and the kitchen are the parts of the building. The object is designed as structural masonry system, ceramic bricks with external thermal insulation composite system. Building does not have a basement. The object is divided to three parts, teaching part, dining room with kitchen and sports hall with facilities. The building has two-storey in the teaching part, the remaining part is a single-storey with vegetation roof. All roofs are designed as a warm flat roof. The building is designed for capacity 150 pupils. Building ventilation is provided by air-conditioning equipment. Entrance to the building is barrier-free, it is installed a building elevator inside.
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Roque, Tiago Guedes. "Optical Character Recognition of Alphanumeric Codes of Ceramic Bowls used in Lost-wax Casting." Master's thesis, 2019. https://hdl.handle.net/10216/119324.
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Alwthinani, Fahad K. "Effect of veneering technique, heat rate, holding time and zirconia thickness on the mechanical properties of porcelain veneers." Thesis, 2016. https://hdl.handle.net/2144/18666.
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OBJECTIVES: Evaluate the effect of different veneering techniques, Y-TZP core thicknesses, and firing cycles with different heat rates and holding times on the mechanical properties of veneering porcelain.
MATERIALS AND METHODS:
Biaxial flexural strength and Thermal shock resistance tests were conducted to evaluate the mechanical properties of veneer porcelain. Core material, Y-TZP and two porcelain veneers, IPS e.max Ceram and VITA VM9, were used in this study. Vita YZ zirconia blocks were sectioned and sintered to provide slabs of 1.65, 3.25, and 6.50mm in thickness. Two techniques were used to fabricate VITA VM9 and e.max Ceram porcelain veneer porcelain discs, Hand Layered, mixing powder with manufacturer’s molding liquid, condensed in a mold, and Pressed, pressing powder uniaxially in a mold. A layer of carbon paint was applied to the zirconia to allow removal of the porcelain discs. For thermal shock test the veneering porcelain fired on the Y-TZP core with a wash layer. After the veneer discs were fabricated, they were sintered: (1) According to the manufacturer’s instructions; (2) Two different cycles with slower heat rate and longer holding than the recommended value. Biaxial flexural strength was determined using a universal mechanical tester. Thermal shock tests were performed using a Pober thermal shock device. Statistical analysis was conducted for all tests using ANOVA and Tukey post hoc test at p= 0.05.
RESULTS:
There was significant effect from changes of YZ Core thickness, firing cycle, and veneer technique on the mechanical properties of porcelain veneer. The veneering technique had the largest impact on the mechanical properties of veneer porcelain followed by firing cycle, followed by YZ core thickness. In using different firing cycles with different heat rates and holding times, slowing the heating rate had more influence on the mechanical properties of veneer porcelain. In measuring the surface temperature of the Y-TZP/VITA VM9 assembly, the specimen surface temperature was coincidental with the furnace programmed firing cycle using a slower heating rate firing cycle.
CONCLUSIONS
Veneering technique, slower heat rate firing cycle, and Y-TZP core thickness have significant impact on veneering porcelain mechanical properties.2018-09-28T00:00:00Z