This diploma thesis consists of two main parts {--} a practical and a theoretical one. The aim of the practical part was to design and create seven ceramic wall clocks and to plant clockworks with hands into them. The theoretical part deals with time measurement in history, it follows the development of time measuring devices from the antiquity to the present. It also describes the techniques used by creating the set of clocks and ideal and motivational sources which have influenced the processing of this topic.

I created the cycle of 5 plastic reliefs with the motifs of space effects in my project. As the first model I chose the moon in fog which it is said about that it has a ghostly power. As the second theme I chose the Earth like the symbol of all living. The third motif is the planet Saturn by which I was impressed with its rings. The fourth theme I called Neptune which is the windiest planet. The last motif is Pluto and it`s the smallest planet. I usted the color designed for low {--} temperature fixation for 170 ° C for thein decoration. As the motivation source were instrumental the creative works of František Peterka in my theoretic work. I verified the using of low {--} temperature stove paint in scholastic practice as compared with the ceramic enamel.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / The Brazilian housing deficit is a problem that primarily affects the poorest part of the population. Its solution is not only to implement huge housing programs or to develop building systems, but also to evaluate these actions through the analysis of its constructability. Lower cost construction systems, tailored to local realities which can ensure to families con fort, safety and quality of life are essential when it comes to design and build social housing - SH (HIS on Portuguese). This paper, therefore, presents the development process of a modular masonry for ceramic blocks, since its conception and design until its implementation in a constructive prototype and analyses the same from the standpoint of constructability. Thus, the study uses a methodology of intensive recording and monitoring of the system's project and implementation phases. It performs a critical analysis of them, investigating, qualitatively, the constructability of the system and proposing improvements for it to reach a higher integrat ion level between projectual and executive phases. As a result, there is a systematic for studying the constructability applicable to other building systems, with results that contribute to continuous improvement on build of social housing / O dÃficit habitacional brasileiro à um problema que afeta principalmente a parcela mais pobre da populaÃÃo. Sua soluÃÃo passa nÃo somente pela execuÃÃo de grandes programas habitacionais ou pelo desenvolvimento de sistemas construtivos, mas tambÃm pela avaliaÃÃo destes por meio da anÃlise de sua construtibilidade. Sistemas construtivos de menor custo, adaptados Ãs realidades locais e que possam garantir Ãs famÃlias conforto, seguranÃa e qualidade de vida sÃo essenciais quando se trata de projetar e executar habitaÃÃes de interesse social - HIS. O presente trabalho, pois, apresenta o processo de desenvolvimento de um sistema modular em alvenaria de blocos cerÃmicos, desde sua concepÃÃo e projeto atà sua aplicaÃÃo na execuÃÃo de um protÃtipo construtivo, e analisa o mesmo sob a Ãtica da construtibilidade. Para tanto, o trabalho utiliza uma metodologia de acompanhamento e registro intensivos das fases de projetaÃÃo e execuÃÃo do sistema e realiza um estudo crÃtico das mesmas, investigando sua construtibilidade qualitativamente e propondo melhorias a fim de que o mesmo alcance um patamar superior de integraÃÃo entre as fases projetual e executiva. Tem-se como resultado uma sistemÃtica de estudo da construtibilidade que pode ser aplicada em outros sistemas construtivos, com a consequÃncia de benefÃcios para a melhoria contÃnua na construÃÃo de habitaÃÃes de interesse social.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Com o desenvolvimento da tecnologia sem fio, muitos dispositivos eletrÃnicos exigem alta integraÃÃo e que possuam propriedades multifuncionais. Em tal caso, compÃsitos magneto-dielÃtricos tÃm atraÃdo muita atenÃÃo devido as suas propriedades. Nesse sentido, a pesquisa sobre compÃsitos à empregada para a busca de novos materiais. O titanato de cÃlcio (CaTiO3 - CTO) e a granada de Ãtrio e ferro (Y3Fe5O12 - YIG) possuem excelentes propriedades dielÃtricas e ferrimagnÃticas, respectivamente. Este trabalho apresenta a obtenÃÃo do compÃsito ferrimagnÃtico, constituÃdo pelas fases YIG e CTO, atravÃs da rota sintÃtica no estado sÃlido com a utilizaÃÃo de moagem mecÃnica de alta energia. As fases das cerÃmicas foram sinterizadas a 1200ÂC/5h. A DifraÃÃo de Raios-X, a Espectroscopia Raman e MÃssbauer foram essenciais para caracterizaÃÃo estrutural dos compÃsitos. A morfologia das amostras foi elucidada pela Microscopia EletrÃnica de Varredura e auxiliada pela Picnometria a fim de avaliar a densificaÃÃo do material. Adicionalmente, foram realizados experimentos para se avaliar o comportamento elÃtrico e magnÃtico dos compÃsitos na faixa de radiofrequÃncia e de micro-ondas, para depois sugerir uma aplicaÃÃo tecnolÃgica cabÃvel. Os resultados obtidos pela DifraÃÃo de Raio X e da Espectroscopia Raman confirmaram que a sÃntese das fases foi realizada de forma satisfatÃria. As anÃlises qualitativas dos espectros MÃssbauer mostraram boa concordÃncia com os resultados apresentados pela DifraÃÃo de raios-x. Os compÃsitos apresentaram permissividade dielÃtrica praticamente constante na faixa de 50 MHz a 1,5 GHz. Ao analisar o aumento e a diminuiÃÃo da concentraÃÃo em massa de CTO e YIG, respectivamente, foi percebido que os valores de εr aumentaram. A partir dos valores obtidos, pode-se sugerir que o compÃsito sintetizado possui potencial para ser utilizado em dispositivos de micro-ondas, tais como para antenas monopolo. / With the development of wireless technology, many electronic devices require high integration and materials with multifunctional properties. In such a case, magneto-dielectric composites have attracted much attention because they have both magnetic and dielectric properties. In this sense, research on composites is employed to search for new materials. The calcium titanate and yttrium iron garnet possess excellent dielectric properties and ferrimagnetic, respectively. This paper presents the preparation of ferrimagnetic composite, comprising the steps Y3Fe5O12 (YIG) and CaTiO3 (CTO) by the solid state synthetic route with the use of high energy mechanical grinding. The phases of the ceramics were sintered at 1200  C for 5 h. The X-ray diffraction, Raman and MÃssbauer Spectroscopy were used to elucidade structural properties of the composites. The morphological characteristics of the samples were elucidated by Scanning Electron Microscopy and supported by Pycnometry to analyze the densification of the material. Furthermore, experiments to evaluate the electrical and magnetic behavior of composites in the range of radiofrequency and microwave were performed and finally an appropriate technological application was suggested. The results obtained by X-Ray Diffraction and Raman spectroscopy confirm that the synthesis of YIG was successfully obtained. The structural characterization of pure and composite samples was performed successfully and the formation of ionic phase in composites YIG-CTO was found, being in the same family of oxide in which the CTO is inserted. Qualitative analysis of the MÃssbauer spectra showed good agreement with the results reported by x-ray diffraction. The dielectric permittivity composites showed almost constant in the range of 50 MHz to 1.5 GHz. Evaluating the increasing and decreasing in mass concentration of CTO and YIG, respectively and it was realized that the values of εr increased. Two profiles was noticed in the compositional series, it can be inferred that the possibility of the reaction of YIG and CTO products may be interfering with the proper measurements.

Orientador: Lourenço Correr Sobrinho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T17:17:38Z (GMT). No. of bitstreams: 1 SundfeldNeto_Daniel_M.pdf: 1559832 bytes, checksum: 2932e7133bbb3a5c5e3840c9967cc5ac (MD5) Previous issue date: 2013 / Resumo: O objetivo neste estudo foi avaliar a influência de diferentes concentrações do ácido fluorídrico (AF) na morfologia da superfície/interface, assim como a resistência de união ao microcisalhamento de dois tipos de cerâmica vítrea: (1) IPS Empress Esthetic (EST), (Ivoclar Vivadent) e (2) IPS e.max Press (EMX), (Ivoclar Vivadent), unidas ao cimento resinoso (Variolink II, Ivoclar-Vivadent), com ou sem aplicação do adesivo (Ad) após a aplicação do silano. Blocos cerâmicos com 8 × 8 × 2 mm de espessura foram separados em 12 grupos, totalizando 24 grupos, de acordo com as concentrações do ácido fluorídrico: 1%, 2,5%, 5%, 7,5%, 10% e 15%. O tempo de condicionamento para a cerâmica EST foi 60 segundos e para EMX, 20 segundos. Todos os blocos foram silanizados após o condicionamento ácido e a sigla 'Ad' nos grupos designados recebeu a aplicação de uma camada de adesivo após a aplicação do silano. Caracterização dos padrões de condicionamento e interfaces de união foram conduzidas pela análise em MEV. Para o ensaio de microcisalhamento, cilindros de cimento resinoso foram confeccionados sobre a superfície da cerâmica condicionada, fotoativados durante 40 segundos e armazenados durante 24 horas em água destilada a 37°C. Os dados foram submetidos à Análise de Variância de 3 fatores e ao teste de Tukey (p<0,05). As imagens de MEV mostraram pobre condicionamento quando utilizado a concentração de 1%, para EST e EMX. HF2,5% mostrou grande remanescente de fase vítrea e ranhuras pouco profundas na superfície das cerâmicas. Padrões semelhantes de condicionamento foram encontrados para HF7,5% e HF10%. Canais profundos foram encontrados para HF15%. Espaços não preenchidos foram encontrados na interface de grupos que não receberam a aplicação do adesivo. O preenchimento desses espações foi encontrado quando se utilizou o adesivo, mostrando uma interface mais contínua e homogênea. Para o teste de microcisalhamento, os resultados não mostraram diferença estatística entre as cerâmicas EST e EMX. Grupos que receberam o adesivo mostraram valores estatisticamente maiores do que o grupo sem adesivo e HF10% e HF15% mostram valores estatisticamente maiores comparados ao HF1% e HF2,5%. Conclusão: A concentração do ácido fluorídrico influenciou na topografia da superfície e nos valores de resistência de união ao microcisalhamento. O adesivo resultou em maiores valores de união e mostrou-se capaz de criar uma interface mais homogênea, resultando em interfaces mais "entrelaçadas" e provavelmente essa característica pode fornecer interfaces mais confiáveis / Abstract: The objective on this study was to evaluate the influence of hydrofluoric acid (HF) concentration on the surface/interface morphology, also the microshear bond strenght on two types of ceramic: (1) IPS Empress Esthetic (EST), (Ivoclar Vivadent), (2) IPS e.max Press (EMX), (Ivoclar Vivadent), bonded to a resin cement (Variolink II, Ivoclar-Vivadent), with or without application of an unfilled resin (UR) after silane application. Each type of ceramic blocks with 8 mm × 8mm × 2 mm in thickness were separated into 12 groups (n=6), totaling 24 groups, according to the hydrofluoric acid concentration: 1%, 2.5%, 5%, 7.5%, 10% and 15%. Etching time was fixed in 60 seconds for EST and 20 seconds for EMX. All the groups were silanated after etching and the acronym 'UR' on the designated groups received a layer of an unfilled resin after silane application. Characterization of the etching patterns and bonding interfaces was conducted by SEM. For the microshear bond test, resin cylinders were built on the etched ceramic surface, photoactivated during 40 seconds and stored in distilled water during 24 hours, 37°C, for later evaluation in a universal testing machine. The data were submitted to three-way ANOVA and Tukey's test (p<0.05). SEM images showed that poor etching was detected when using HF 1% on EST and EMX groups. HF 2.5% resulted in large remnants of vitreous phase and shallow grooves on ceramic surface. Similar etching patterns were detected for HF 7.5 and 10%. Deep channels were extensively observed on surfaces etched with HF 15%. Unfilled voids underlying the ceramic-resin cement interface were detected in groups that did not receive the application of the unfilled resin. Fully completion of the irregularities was detected using unfilled resin. Overall, when both silane and unfilled resin were applied, all groups generally showed more continuously and homogeneous interfaces. For microshear bond test, the results showed no statistical difference among EST and EMX. Groups with unfilled resin showed statistical higher microshear bond values than groups that did not received this treatment and HF10% and HF15% showed statistical higher values compared to HF1% and HF2.5%. Conclusion: Hydrofluoric acid concentration influenced the ceramic topography and microsher bond strength values. Unfilled resin seems to create more homogeneous interfaces and its application was able to infiltrate the unfilled voids beneath the ceramic-resin cement interface, resulting in more entangled interfaces and probably this feature could result in more reliable interfaces / Mestrado / Materiais Dentarios / Mestre em Materiais Dentários

Orientador: Alvaro Della Bona, Altair A. Del Bel Cury / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T13:44:44Z (GMT). No. of bitstreams: 1 Boscato_Noeli_D.pdf: 1647960 bytes, checksum: 3d012e02dce78a5277da1ede4cc574e4 (MD5) Previous issue date: 2005 / Resumo: Este estudo avaliou o efeito do tratamento de superfície na resistência adesiva à tração (s) entre resina e as cerâmicas IPS Empress®(E1) e VITAVM7®(V7) e o modo de falha nessa interface adesiva. A metodologia proposta teve por finalidade testar a hipótese de que a s entre resina e cerâmica é controlada pelo tratamento de superfície das cerâmicas. Foram confeccionados 10 blocos de uma cerâmica a base de leucita, (E1) e de uma cerâmica feldspática com duas fases vítreas (V7), que foram polidos até a granulação de 1 µm. Os blocos de cada cerâmica foram divididos aleatoriamente em dois grupos e tiveram suas superfícies tratadas como segue (n=5): Grupos E1HF e V7HF: aplicação de ácido hidrofluorídrico a 9,5% (HF - Ultradent) aplicado por 60 s; Grupos E1CS e V7CS: jateamento com partículas de alumina modificadas por sílica (CS ¿ Cojet System, 3M-Espe), aplicado por 15 s. As superfícies cerâmicas tratadas foram lavadas, secadas e o silano foi aplicado deixando-o evaporar. Aplicaram-se duas camadas finas de adesivo (Single Bond, 3M), seguido da aplicação de camadas de 2 mm de resina composta (Z250, 3M), que foram fotopolimerizadas durante 40 s cada uma. Os blocos cerâmica-adesivo-resina composta foram seccionados em dois eixos, x e y, obtendo-se corpos-de-prova em forma de barras (n=30), com área adesiva média de 1,04 mm2. Os corpos-de-prova foram armazenados em água destilada a 37°C por uma semana antes do teste de tração em uma máquina de ensaios universal com velocidade de carga de 1.0 mm.min-1, seguido da análise microscópica da superfície fraturada. A análise estatística foi realizada pela análise de variância, teste de Tukey (a=.01) e análise de Weibull. As médias e desvio padrão da s (MPa) foram: E1HF: 29,8±4,5(a); E1CS: 24,6±5,6(b); V7HF: 22,3±4,0(b); V7CS: 15,7±6,9(c). Os valores médios de s do Grupo E1HF foram significativamente maiores que os valores médios dos demais grupos (p=0,0001). As duas cerâmicas apresentaram valores médios de s significativamente maiores quando tratadas com HF do que com CS (p=0,0001). Todas as fraturas ocorreram dentro da zona adesiva. O módulo de Weibull (m) foi mais alto para o Grupo E1HF (7,66), e o Grupo V7CS mostrou o valor mais baixo de m (2,54). Os resultados confirmam a hipótese inicial de que a s da resina à cerâmica é controlada, primariamente, pelo tratamento de superfície do material cerâmico / Abstract: This study evaluated the effect of ceramic surface treatments on tensile bond strength (s) and the mode of failure of a resin bonded to two types of ceramics, testing the hypothesis that s of ceramics to resin is controlled by the ceramic surface treatment. Methods: Ten blocks of each the hot-pressed leucite-based ceramic (E1- IPS Empress) and the two-phase glassy feldspathic ceramic (V7-VITAVM7) were fabricated, polished through 1 µm alumina abrasive, and divided into two groups per ceramic (n=5): Groups E1HF and V7HF, 9.5% hydrofluoric acid (HF) was applied for 60 s; Groups E1CS e V7CS, silica coating (CS) using Cojet System (3M-Espe) for 15 s. The treated ceramic surfaces were washed and dried. Silane was applied and let to evaporate. An adhesive resin (Single Bond, 3M) followed by a resin composite (Z250, 3M) were applied on the ceramic treated surfaces and light cured. The composite-ceramic blocks were cut to produce bar-shaped specimens with a mean bonding area of 1.04 mm2 (n=30). Specimens were stored in 37°C distilled water for 1 week before tensile loading to failure in a universal testing machine with cross-head speed of 1.0 mm.min-1. Fracture surfaces were examined under scanning electron microscope (SEM). Results were statistically analyzed using one way ANOVA, Tukey¿s test and Weibull analyses. Results: Mean s and standard deviation (MPa) values were as follows: E1HF: 29.8±4.5(a); E1CS: 24.6±5.6(b); V7HF: 22.3±4.0(b); V7CS: 15.7±6.9(c). Mean s value of Group E1HF was statistically higher than the other Groups mean values (p=0.0001). HF treatment produced significantly higher mean s value than CS treatment, independent of the ceramic material (p=0.0001). All fractures occurred within the adhesion zone. E1HF showed the highest Weibull modulus (m) value (7.66) and V7CS exhibited the lowest m value (2.54). Conclusion: Results confirmed the testing hypothesis that s of ceramics to resin is controlled primarily by the ceramic surface treatment / Doutorado / Protese Dental / Doutor em Clínica Odontológica

Yttria stabilized zirconia (YSZ) coatings were produced from a YSZ suspension in acetylacetone (ACAC) using electrophoretic deposition (EPD) and then consolidated via the natural drying and isothermal sintering with the constraint of the metal substrates. Before EPD, the operational pH of the suspension was adjusted by addition of acetic acid or organic bases. The effect of suspension pH on the deposition of EPD coatings was studied with respect to the suspension stability, coating density and microstructure both for a mono-sized system and micro-nano binary systems. The constrained drying process of the deposits was examined via the measurement of the critical cracking thickness (CCT). The sinterability of coatings was evaluated by micro-hardness and microstructure. For a mono-sized (0.26μm) suspension, results showed that the zeta potential had a high positive value on both sides of the isoelectric point (IEP). This probably resulted from the adsorption of base molecules triethanolamine (TEA), detected by fourier transform infrared spectroscopy. Three alkalis with different molecular structure were compared and the effect of their molecule length on the interparticle repulsion was discussed. Accordingly, the double layer thickness of the particles can be estimated. Based on this, particle interactions were estimated for different pH suspensions. The reduced particle coagulation increased the packing density of the EPD coatings from 38 % at pH 7.4 to 53 % at pH 8.4. Therefore, subsequent sintering of coatings was promoted. After sintering at 1200 °C, coatings made in pH 8.4 suspensions obtained a much higher hardness and had fewer big pores than coatings fabricated in pH 7.4 suspensions. The CCT of the latter is slightly higher than the former which might be ascribed to its particle network structure. In a binary suspension composed of the coarse (1μm) and fine (with average size of 100 nm or 10 nm, content varied in 0-30 wt. % to the powder mixture) YSZ powders, interactions between different species can be tuned by the zeta potential of individual component. Binary particles can be well dispersed at pH 4 when both of the coarse and fine powders reached their highest zeta potentials. Heterocoagulation occurred between them to form a haloing structure with fine powders covered on the coarse particle surfaces when they exhibited zeta potentials of the opposite sign at pH 8.6. Particle interactions were estimated and the microstructures of the binary coatings were examined to discuss how the different fine particle sizes influenced the particle packing after EPD. At pH 4, there existed a “stability window” for the 10 nm fines at 10 wt. % whereas no noticeable the border of the window can be observed for 100 nm fines within the measuring range. 10 nm and 100 nm fine powders gave similar overall densities of binary EPD coatings which were independent of the fine powder content. For heterocoagulation coatings made at pH 8.6, although the adsorption of fine particles reduce the agglomeration of coarse powder, the low zeta potential of the halos led to a loose structure of the “skeleton” ( the packing of the coarse powder) in the final binary coatings. 10 nm fine powders was observed to give a higher CCT and denser particle packing than 100 nm fine powders especially in a pre-saturated heterocoagulated binary coatings at 20 wt. % fine powder content. In order to further improve the sintering of the EPD coatings at low temperature sintering, a layer of CuO was applied on the coarse powder surface. With the addition of 30 wt. % fine powders, the hardness of EPD coatings after sintering 2 hours at 1150°C increased from 6 to 61 Vickers. With the presence of CuO, the hardness values were enhanced by 2.5-4.25 times. The density measurements indicated that the CuO layer not only served as a sintering aid, the CuO layer also helped with the binary particle packing particularly in the heterocoagulation condition because of the stronger particle interactions between the fine powders and CuO modified coarse powders. It seems that CuO had no significant impact on the cracking resistance of the binary coatings during drying, however t-m phase transformation was observed during sintering possibly due to the liquid phase induce by CuO.

A novel and new thermal management technology for advanced ceramic microelectronic packages has been developed incorporating miniature heat pipes embedded in the ceramic substrate. The heat pipes use an axially grooved wick structure and water as the working fluid. Prototype substrate/heat pipe systems were fabricated using high temperature co-fired ceramic (alumina). The heat pipes were nominally 81 mm in length, 10 mm in width, and 4 mm in height, and were charged with approximately 50-80 mL of water. Platinum thick film heaters were fabricated on the surface of the substrate to simulate heat dissipating electronic components. Several thermocouples were affixed to the substrate to monitor temperature. One end of the substrate was affixed to a heat sink maintained at constant temperature. The prototypes were tested and shown to successful and reliably operate with thermal loads over 20 Watts, with thermal input from single and multiple sources along the surface of the substrate. Temperature distributions are discussed for the various configurations and the effective thermal resistance of the substrate/heat pipe system is calculated. Finite element analysis was used to support the experimental findings and better understand the sources of the system's thermal resistance.

The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications. The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.

My master’s thesis deals with the problems of NOx abatement that are included in flue gases. The accent is put on combined flue gases treatment throug ceramic candles, where the deposited catalyst enables NOx reduction throug the method of selective catalytic reduction. The main aim of my master’s thesis has been the design of experimental equipment for current removal of gas pollutants (dioxins, VOC and NOx) and fly-ash on catalitic ceramic candle. Design of experimental equipment consisted in the calculation of basic characteristics like pipe diameter, filtration chamber diameter, heater performance etc. During the design it was necessary to build pressure drop model that was split into head loss of ceramic candle and piping system. For the evaluation of experimentally measured data and for description of ongoing catalytic reaction in various operating conditions was made prediction model of catalytical filter. The last chapter deals with planned experimental testings.