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Search Results: 1 - 10 of 585709 matches for " A. N.;Pianaro "
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Lodo gerado na esta??o de tratamento de água Tamanduá, Foz do Igua?u, PR, como aditivo em argilas para ceramica vermelha: Parte I: caracteriza??o do lodo e de argilas do terceiro planalto paranaense
Tartari, R.;Díaz-Mora, N.;Módenes, A. N.;Pianaro, S. A.;
Ceramica , 2011, DOI: 10.1590/S0366-69132011000300006
Abstract: with a view to investigate the incorporation of sludge generated in eta tamanduá masses for red ceramics, such as disposal method, this paper aims to characterize the sludge eta tamanduá and four clays of western paraná used to produce structural red ceramic and artistic ceramic, to evaluate the technological potential of this residue. in this first experimental phase of characterization, we determined the moisture, chemical composition by x-ray fluorescence, crystalline compounds by x-ray diffraction, atterberg limits of soils (atterberg), size distribution and structure of particles by electron microscopy (sem). it is noteworthy that the clays have properties favorable for the production of red ceramics. the sludge has basic features of the raw material of low plasticity, composed mainly of sio2, al2o3 and fe2o3, with high loss on ignition (20.4%), low plasticity index equal to (7.4), fraction clay corresponding to 5.3%. these characteristics suggested the possibility that, in the second stage, incorporate the sludge with natural moisture (75%) as an additive in ceramic body, to reduce the shrinkage and to minimize the addition of water to the masses for the production of red ceramics.
Lodo gerado na esta??o de tratamento de água Tamanduá, Foz do Igua?u, PR, como aditivo em argilas para ceramica vermelha: Parte II: incorpora??o do lodo em mistura de argilas para produ??o de ceramica vermelha
Tartari, R.;Módenes, A. N.;Pianaro, S. A.;Díaz-Mora, N.;
Ceramica , 2011, DOI: 10.1590/S0366-69132011000400003
Abstract: the research addresses this second stage, binary mixtures of clays ceramic santa rita and the cooperative of artisans from foz do igua?u, pr, in different weight percentages, for making specimens by uniaxial pressing, sintered at temperatures of 950 and 1050 oc, and analyzed by technological tests of red ceramic. in compositions among the clays that were better at processing, proportions of 4, 8, 12 and 16% of the waste sludge were added in order to add mass. it was identified in the results of the production of building blocks 6-hole extrusion process by which 8% is the maximum of sludge to be added to the ceramic body, which was not identified cracks and deformations with linear shrinkage in the order of 8.6% water absorption of 24.6% and compressive strength of 42.6 kgf/cm2 in accordance with the standards for the production of red ceramic coating (bricks).
Prepara??o e caracteriza??o de materiais compósitos SiC/caulim/Al via "squeeze-casting"
Freitas, M.;Pianaro, S. A.;Nadal, F. N.;Tebcherani, S. M.;Berg, E. A. T.;
Ceramica , 2009, DOI: 10.1590/S0366-69132009000300006
Abstract: in search of materials with different properties, has been increasing the research on composite materials in recent years. one of the important methods of manufacturing these composites is the process of metal casting infiltration under pressure called squeeze-casting. this process offers some advantages, such as ease of producing the composite, low cost and ability to form network structures. in this work were produced and characterized al-sic composites, with concentrations in kaolin ranging between 10 and 50% in place to sic majority phase. the ceramic pre-forms were produced to controlling the fraction of the size sic/kaolin for better infiltration. these pre-forms after sintering at 1100 oc/1 h resulted highly porous, and the porosity increased with the increase of kaolin in place to sic particles. xrd analysis showed the existence of quartz particles beyond the sic phase. during the infiltration and heat treatment process, the liquid aluminum reacted preferably with quartz and other aluminosilicates particles of the pre-form reducing them, precipitating alumina and silicon in the microstructure, which also presented aluminum in excess that not reacted in the process. the silica and silicates of pre-form, reacted preferably with the aluminum, preventing the formation of al4c3 phase, which is highly hygroscopic and causes the composite degradation. depending on the composition, the sic - kaolin - al composite developed in this work, can be used in applications involving high bending mechanical resistance (240 to 300 mpa), low density and hardness surface between 180 and 380 kgf/mm2.
Simula??o da difus?o do zinco e do oxigênio, e análise da durabilidade de varistor de ZnO utilizando o planejamento fatorial
Pariona, M. M.;Pianaro, S. A.;
Ceramica , 2000, DOI: 10.1590/S0366-69132000000300005
Abstract: the durability of the zno varistor is related with its electric, microstructural and thermal characteristics, and with the phenomenon of mass transport at grain boundaries under varistor operation. the polarization state at grain boundaries is related to the diffusion of zinc, oxygen and dopants during the application of the electric potential and/or of the temperature. when the electric potential is removed and the polarization state doesn't recover its natural state, the device presents the worst parameters and the varistor degrades, decreasing its lifetime. in this work, a simulation of the diffusion of interstitial zinc and of oxygen vacancy in zno varistor is done. in addition, the durability of the varistor was simulated, through the factorial design of electric, thermal and geometric parameters that characterize the device. it was found that the diffusion of the interstitial zinc controls mainly the electrical properties of the varistor. it was also observed that when the temperature is increased and the tension drops to 0.5 ma/cm2, the lifetime of the varistor decreases.
Simula o da difus o do zinco e do oxigênio, e análise da durabilidade de varistor de ZnO utilizando o planejamento fatorial
Pariona M. M.,Pianaro S. A.
Ceramica , 2000,
Abstract: A durabilidade do varistor de ZnO está relacionada com suas características elétricas, microestruturais, térmicas e com o fen meno de transporte de massa nos contornos de gr o durante o processo de opera o do varistor. O estado de polariza o nos contornos de gr o está relacionado com a difus o do zinco, do oxigênio e dos dopantes durante a aplica o do potencial elétrico e/ou da temperatura. Quando o potencial elétrico é retirado e o estado de polariza o n o recupera seu estado natural, significa que o dispositivo adquire os piores parametros e o varistor sofre degrada o, comprometendo sua durabilidade. Neste trabalho, foi simulada a difus o do zinco intersticial e das vacancias de oxigênio em ZnO. Foi também simulada a durabilidade do varistor, através do planejamento fatorial dos parametros elétricos, térmicos e geométricos que caracterizam o dispositivo. Através destes resultados, verificou-se que a difus o do zinco intersticial controla principalmente as propriedades elétricas. Observou-se, também, que quando aumenta a temperatura e a queda de tens o registrada em 0,5 mA/cm2, a durabilidade do varistor fica comprometida.
A forma??o e o estágio atual do grupo de materiais ceramicos (GPMC) da UEPG
Pianaro, S. A.;Antunes, S. R. M.;Zara, A. J.;Antunes, A. C.;
Ceramica , 1999, DOI: 10.1590/S0366-69131999000400006
Abstract: the group of ceramic materials belongs to the center for interdisciplinary research on materials of the state university of ponta grossa, paraná. the group, with more than nine researchers and eighteen undergraduate students is directed by prof. s. a. pianaro. the main research area is in electronic ceramics with emphasis in sno2 varistors. besides, some research work is performed on pigments, glass-ceramics and reuse of ceramic materials.
Síntese e caracteriza??o do sistema ZrO2-SiO2 com adi??o de cobalto para uso como pigmentos ceramicos
Cava, S.;Tebcherani, S. M.;Pianaro, S. A.;Paskocimas, C. A.;Longo, E.;Varela, J. A.;
Ceramica , 2005, DOI: 10.1590/S0366-69132005000300021
Abstract: co-doped zrsio4 powders were synthesized by the polymeric precursor method to obtain ceramic pigments. the effect of different co2+ contents on the t-zro2 to zrsio4 phase transition was studied by x-ray diffraction and differential thermal analysis. uv-vis spectroscopy of the samples allowed comparing the band shift with the phase transition. moreover, a study of the thermal stability and intensity of the blue to red color change of the synthesized powders with the presence of cobalt in relation to the calcination temperature was accomplished and compared to the phase transition. the results allowed to identify the t-zro2 to zrsio4 phase transition.
A forma o e o estágio atual do grupo de materiais ceramicos (GPMC) da UEPG
Pianaro S. A.,Antunes S. R. M.,Zara A. J.,Antunes A. C.
Ceramica , 1999,
Abstract: Dentro da área de materiais, a Universidade Estadual de Ponta Grossa possui um Centro Interdisciplinar de Pesquisas em Materiais, do qual o grupo de materiais ceramicos faz parte. O grupo é coordenado pelo professor Sidnei Ant nio Pianaro e conta com mais 9 pesquisadores e, atualmente, com 18 alunos de inicia o científica. A principal linha de pesquisa desenvolvida é na área de ceramica eletr nica, podendo destacar as pesquisas em varistores a base de SnO2. Além destas pesquisas, est o sendo desenvolvidos projetos nas linhas de pigmentos, vidrados, vitro-ceramicas e reciclagem de materiais ceramicos.
Investiga??o da cinética de sinteriza??o para o estágio inicial no sistema SnO2: ZnO
Kupchak, L.;Antunes, S. R. M.;Parizotto, M. V.;Tebcherani, S. M.;Setti, D.;Pianaro, S. A.;Antunes, A. C.;
Ceramica , 2005, DOI: 10.1590/S0366-69132005000300022
Abstract: the sintering of sno2:0.6 mol% zno obtained by powder mixtures was investigated by dilatometry at constant heating rates 2.5, 5.0 and 10.0 oc.min-1. using classical sintering models of woolfrey-bannister and johnson to analyze the initial stage sintering, the calculated activation energy was 547 kj.mol-1 and 511 kj.mol-1, respectively. the coexistence of the two sintering mechanisms, volume diffusion and grain boundary diffusion, was found to control the initial stage sintering of the sno2:0.6 mol % zno system.
Luciana Pianaro,Reynaldo Cavalheiro Marcondes
Revista de Administra??o FACES Journal , 2008,
Abstract: Este artigo trata das estrat gias de marketing utilizadas pelas marcas internacionais do segmento de roupas e acess 3rios de luxo atuantes no mercado brasileiro. Baseia-se em estudo explorat 3rio apoiado por entrevistas em profundidade com sete executivos ligados s marcas Armani, Burberry, Diesel, Dior, Louis Vuitton, Versace e Zegna, com um roteiro semiestruturado. Os dados foram tratados e analisados com base na an lise de conte odo. As revela § μes mais significativas foram: as marcas trabalham com quatro cole § μes anuais, as quais s £o comercializadas em esta § μes opostas quelas do hemisf rio norte; o parcelamento das compras pr tica relevante entre elas, considerado um fato cultural e tido como uma vantagem em rela § £o s lojas em outros pa -ses; as pe §as de marketing s £o mundiais, geradas pela matriz; todas as marcas est £o focadas na reputa § £o e exclusividade da marca; todas as lojas oferecem servi §os adicionais gratuitos, chegando a montar um showroom da marca na casa de clientes muito especiais.
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