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Search Results: 1 - 10 of 463966 matches for " Rabelo Adriano A. "
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Characterization of high-energy milled alumina powders
Tomasi, Roberto;Rabelo, Adriano A.;Chinelatto, Adriana S. A.;Reis, Laudo;Botta Fo, Walter J.;
Ceramica , 1998, DOI: 10.1590/S0366-69131998000500003
Abstract: the utilization of reactive high-energy milling has been reported for the synthesis of ceramic powders namely, metal oxides, carbides, borides, nitrides or mixtures of ceramics or ceramic and metal compounds. in this work, high-energy milling was used for reduction of alumina powders to nanometric particle size. the ceramic characteristics of the powders were analyzed in terms of the behavior during deagglomeration, compaction curves, sintering and microstructure characterization. it was observed that the high energy milling has strong effect in producing agglomeration of the nanosized powders. this effect is explained by the high-energy impact of the balls, which may fracture particles or just cause the particles compacting. in this case, strong agglomerates are produced. as the powder surface area increases, stronger agglomerates are produced.
Characterization of high-energy milled alumina powders
Tomasi Roberto,Rabelo Adriano A.,Chinelatto Adriana S. A.,Reis Laudo
Ceramica , 1998,
Abstract: The utilization of reactive high-energy milling has been reported for the synthesis of ceramic powders namely, metal oxides, carbides, borides, nitrides or mixtures of ceramics or ceramic and metal compounds. In this work, high-energy milling was used for reduction of alumina powders to nanometric particle size. The ceramic characteristics of the powders were analyzed in terms of the behavior during deagglomeration, compaction curves, sintering and microstructure characterization. It was observed that the high energy milling has strong effect in producing agglomeration of the nanosized powders. This effect is explained by the high-energy impact of the balls, which may fracture particles or just cause the particles compacting. In this case, strong agglomerates are produced. As the powder surface area increases, stronger agglomerates are produced.
Eugene O'Neill e a tragédia moderna
Rabelo, Adriano de Paula;
Estudos Avan?ados , 2010, DOI: 10.1590/S0103-40142010000300014
Abstract: considered the most eminent american dramatist and one of the twentieth century most important authors, eugene o'neill always had the purpose of recreating tragedy through the values and references of his time. this paper is divided in three parts: the first one focuses some aspects of his biography; the second one, his works; and the third one, systematic aspects on his conception of the modern tragic.
Um mundo substituído: jornalismo e jornalistas nas memórias de Nelson Rodrigues
Adriano de Paula Rabelo
Revista Comunica??o Midiática , 2011,
Abstract: This article approaches the development of journalism as well as the journalists work in Brazil as they are seen in Nelson Rodrigues memoirs, which were published as a book in 1993, untitled A Menina sem Estrela. In the first part, there is a short division of the history of journalism in periods. Then there comes a discussion of the way this activity is presented in the authors drama. The following part deals with the theory of fiction that support Rodrigues texts. Finally all attention is concentrated on the way journalism and journalists are presented in his memoirs.
Three electrode electrochemical microfluidic cell: construction and characterization
Silva, Rodrigo A. B. da;Almeida, Edimar G. N. de;Rabelo, Adriano C.;Silva, Abílio T. C. da;Ferreira, Lucas F.;Richter, Eduardo M.;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000700006
Abstract: this work describes the construction and characterization of an electrochemical flow-through microcell with the three electrodes (working, pseudo-reference, and auxiliary) inserted in microchannels with thickness smaller than 20 μm. these microchannels were constructed between two stacked polycarbonate slides using one or more overlapped toner masks as spacer. this strategy allows the construction of microcells with a variable internal volume on the working electrode (0.6 to 2.4 μl). three different materials were optimized as electrodes: gold film or graphite-epoxy composite as working electrode, silver-epoxy composite as pseudo-reference electrode and, graphite-epoxy composite as auxiliary electrode. the performance of the microfluidic cell was characterized by cyclic voltammetry, potentiometric stripping analysis at constant current, and square wave anodic stripping voltammetry using ferrocyanide and heavy metals (cu2+, hg2+, pb2+, and cd2+) as model analytes.
Finding invariant tori in the problem of a periodically corrugated waveguide
Rabelo, Adriano Fábio;Leonel, Edson D.;
Brazilian Journal of Physics , 2008, DOI: 10.1590/S0103-97332008000100010
Abstract: some dynamic properties for a light ray suffering specular reflections inside a periodically corrugated waveguide are studied. the dynamics of the model is described in terms of a two dimensional nonlinear area preserving map. we show that the phase space is mixed in the sense that there are kam islands surrounded by a large chaotic sea that is confined by two invariant spanning curves. we have used a connection with the standard mapping near a transition from local to global chaos and found the position of these two invariant spanning curves limiting the size of the chaotic sea as function of the control parameter.
Síntese de manganita de lantanio com substitui??o parcial do La por Sr pelo método citrato
Silva, Walquíria Joseane da;Melo, Dulce Maria de Araújo;Soares, Sibelle Feitosa da Cunha X.;Pimentel, Patrícia Mendon?a;Nascimento, Rubens Maribondo do;Martinelli, Antonio Eduardo;Rabelo, Adriano Alves;
Matéria (Rio de Janeiro) , 2007, DOI: 10.1590/S1517-70762007000100009
Abstract: lanthanum manganite is a type p intrinsic semiconductor ceramic oxide with perovskite structure. the partial substitution in a-site of that material increases it?s electrical conductivity, becoming appropriate to be used in production of solid oxide fuel cells (sofc) component for working at temperatures around at 1000 °c. in general, the properties of materials change with composition and synthesis method. in the present work, the synthesis of la1-xsrxmno3 (x = 0,20-0,22) has been carried out by citrate method, aiming at to investigate the percentage effect of the dopante in the formation of the perovskite phase. this method allows to obtain homogenous powders and crystalline phase in lower temperatures than traditional methods of synthesis. the sample was characterized by x-ray diffraction (xrd), thermal gravimetric analyses (tga), scanning electron microscopy (sem) and analysis by specific surface area by bet method. the powders synthesized with 22% partial substitution of strontium showed better results relative to obtain perovskite phase.
A constru??o de cidades saudáveis: uma estratégia viável para a melhoria da qualidade de vida?
Adriano,Jaime Rabelo; Werneck,Gustavo Azeredo Furquim; Santos,Max André dos; Souza,Rita de Cássia;
Ciência & Saúde Coletiva , 2000, DOI: 10.1590/S1413-81232000000100006
Abstract: this paper aims at discussing the importance of the healthy city movement as a strategy to improve the quality of life of the population. from the movement's present context both in the brazil and in the world, a pilot experiment carried out in 1996-1998, in the cities of dionísio and s?o josé do goiabal, in the brazilian state of minas gerais, is presented and analyzed. taking interdisciplinarity, intersectorality and participation as basic assumptions, the strategic planning methodology proposed by carlos matus was used to develop an action plan to face priority problems in the municipalities. the active participation of community groups was encouraged so that at the end of the process this methodology could be assimilated by and incorporated to the routine of municipal administrations. this paper shows some preliminary results and discusses the advantages and constraints of this process.
Obten??o de filmes espessos de seleneto de cobre sobre carbono vítreo, ouro, titanio e cobre
Rabelo, Adriano César;Arantes, Tatiane Moraes;Bottecchia, Otávio Luiz;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000200009
Abstract: copper selenide (berzelianite) films were prepared on the title substrates using the chemical bath deposition technique (cbd). film composition was determined by energy dispersion of x-rays. the kinetics of film growth is parabolic and film adherence limits the film thickness. on titanium, copper selenide forms islands that do not completely cover the surface, unless the substrate is prepared with a tin oxide layer; film composition also depends on the titanium oxide layer. on vitreous carbon, cbd and mechanical immobilization techniques lead to films with similar resistances for the electron transfer across the film/substrate interface. on gold, composition studies revealed that film composition is always the same if the ph is in the range from 8 to 12, in contrast to films prepared by an ion-ion combination route. on copper, a new procedure for obtaining copper selenide films as thick as 5 μm has been developed.
Sequencing and expression analysis of a Schistosoma mansoni gene homologue to a Drosophila gene involved in germ plasm assembly
Rabelo élida ML,Hobaika Adriano BS,Coelho Paulo Marcos Z,Pena Sérgio DJ
Memórias do Instituto Oswaldo Cruz , 1998,
Abstract:
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