992 resultados para 48-405
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The technique of nebulized spray pyrolysis has been explored to find out whether oriented films of certain important oxides can be produced on single-crystal substrates by this relatively gentle method. Starting with acetylacetonate precursors, oriented films of metallic LaNiO3 containing nearly spherical grains (30 nm) have been obtained. Films of near-stoichiometric La4Ni3O10 and La3Ni2O7 showing metallic conductivity have been obtained by this method. This is indeed gratifying since it is difficult to prepare monophasic and stoichiometric bulk samples of these materials. Films of La2NiO4 show the expected semiconducting behavior. In the La-Cu-O system, starting with acetylacetonates, we have obtained films mainly comprising semiconducting La2Cu2O5, which is generally difficult to prepare in bulk form. More interestingly, nebulized spray pyrolysis gives excellent stoichiometric films of Pb(Zr0.52Ti0.48)O-3 consisting of nearly spherical grains (30 nm) which show ferroelectric behavior. The present investigation demonstrates that nebulized spray pyrolysis provides a useful and desirable route to deposite oriented films of complex oxide materials on single-crystal substrates.
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A new two-step synthesis of ZrO2-MCM nanocomposites using the gel combustion technique was accomplished; the resulting material had a high-surface area and showed very high adsorption activity. The deposition of 25 nm ZrO2 particles over MCM was achieved using gel combustion technique with glycine as a fuel, and the formation of nanocomposites was confirmed using transmission electron microscopy. The composites were also characterized by XRD, SEM, FTIR and N2 adsorption-desorption analysis. The nanocomposites were tested for the adsorption of cationic dyes. High rates of adsorption and large dye uptake were observed over the nanocomposites. The rate of adsorption over the nanocomposites was higher than that observed for physical ZrO2-MCM mixtures and commercial activated carbon. The nanocomposite with 10 wt % ZrO2 showed the highest rate of adsorption owing to the synergistic effects of ZrO2 surface groups, smaller particle size, fine dispersion and high-surface area of the composite. (c) 2012 American Institute of Chemical Engineers AIChE J, 58: 29872996, 2012
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The frequency-dependent dielectric relaxation of Pb0.94Sr0.06](Mn1/3Sb2/3)(0.05)(Zr0.52Ti0.48)(0.95)]O-3 ceramics, synthesized in pure perovskite phase by a solid-state reaction technique is investigated in the temperature range from 303 to 773 K by alternating-current impedance spectroscopy. Using Cole-Cole model, an analysis of the imaginary part of the dielectric permittivity with frequency is performed assuming a distribution of relaxation times. The scaling behavior of the imaginary part of the electric modulus suggests that the relaxation describes the same mechanism at various temperatures. The variation of dielectric constant with temperature is explained considering the space-charge polarization. The SEM indicates that the sample has single phase with an average grain size similar to 14.2 mu m. The material exhibits tetragonal structure. A detailed temperature dependent dielectric study at various frequencies has also been performed. (C) 2013 Elsevier B.V. All rights reserved.
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We report high aspect-ratio micromechanical structures made of SU-8 polymer, which is a negative photoresist. Mask-less direct writing with 405 nm laser is used to pattern spin-cast SU-8 films of thickness of more than 600 um. As compared with X-ray lithography, which helps pattern material to give aspect ratios of 1:50 or higher, laser writing is a less expensive and more accessible alternative. In this work, aspect ratios up to 1:30 were obtained on narrow pillars and cantilever structures. Deep vertical patterning was achieved in multiple exposures of the surface with varying dosages given at periodic intervals of sufficient duration. It was found that a time lag between successive exposures at the same location helps the material recover from the transient changes that occur during exposure to the laser. This gives vertical sidewalls to the resulting structures. The time-lags and dosages were determined by conducting several trials. The micromechanical structures obtained with laser writing are compared with those obtained with traditional UV lithography as well as e-beam lithography. Laser writing gives not only high aspect ratios but also narrow gaps whereas e-beam can only give narrow gaps over very small depths. Unlike traditional UV lithography, laser writing does not need a mask. Furthermore, there is no adjustment for varying the dosage in traditional UV lithography. A drawback of this method compared to UV lithography is that the writing time increases. Some test structures as well as a compliant microgripper are fabricated.
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The authors prepared (1 - x) BiFeO3 - (x)Pb(Zr0.52Ti0.48)O-3 for x <= 0.30 by sol-gel method and investigated the material's structures, magnetic and electrical properties. Detailed Rietveld analysis of X-ray diffraction data revealed that the system retains distorted rhombohedral R3c structure for x <= 0.10 but transforms to monoclinic (Cc) structure for x > 0.10. Disappearance of some Raman modes corresponding to A1 modes and the decrease in the intensities of the remaining A1 modes with increasing x in the Raman spectra, which is a clear indication of structural modification and symmetry changes brought about by PZT doping. Enhanced magnetization with PZT doping content may be attributed to the gradual change and destruction in the spin cycloid structure of BiFeO3. The leakage current density at 3.5 kV/cm was reduced by approximately three orders of magnitude by doping PZT (x = 0.30), compared with BFO ceramics. (C) 2014 AIP Publishing LLC.
Resumo:
Compositions with x <= 0.30 in the system (1- x)Pb(Zro(0.52)Ti(0.48))O-3-(x)BiFeO3 were synthesized by sol-gel method. Rietveld analysis of X-ray diffraction data reveals tetragonal structure (P4mm) for x <= 0.05 and monoclinic (Cm) phase along with the existence of tetragonal phase for 0.10 <= x <= 0.25 and monoclinic phase for x = 0.30. Transformation of E(2TO) and E + B1 vibrational modes in the range 210-250 cm(-1) (present for x <= 0.25) into A' + A `' modes at similar to 236 cm(-1) for x = 0.30, and occurrence of new vibrational modes A' and A `' in Raman spectra for x >= 0.10 unambiguously support the presence of monoclinic phase. Occurrence of remnant polarisation and enhanced magnetization with concentration of BiFeO3 indicates superior multiferroic properties. Variation of magneto-capacitance with applied magnetic field is a strong evidence of magneto-electric multiferroic coupling in these materials. (C) 2014 Elsevier B.V. All rights reserved.
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Iridium-functionalized multiwalled carbon nanotubes (Ir-MWNT) are the future catalyst support material for hydrazine fuel decomposition. The present work demonstrates decoration of iridium particle on iron-encapsulated multiwalled carbon nanotubes (MWNT) by wet impregnation method in the absence of any stabilizer. Electron microscopy studies reveal the coated iridium particle size in the range of 5-10 nm. Elemental analysis by energy dispersive X-ray diffraction confirms 21 wt% of Ir coated over MWNT. X-ray photoelectron spectroscopy (XPS) shows 4f(5/2) and 4f(7/2) lines of iridium and confirms the metallic nature. The catalytic activity of Ir-MWNT/Shell 405 combination is performed in 1 N hydrazine micro-thrusters. The thruster performance shows increase in chamber pressure and decrease in chamber temperature when compared to Shell 405 alone. This enhanced performance is due to high thermal conducting nature of MWNTs and the presence of Ir active sites over MWNTs.
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Contenido: Grandeza y limitación de la filosofía / La Dirección – Epistemología del conocimiento de la historia / Octavio N. Derisi – Despotismo universal y Katéchon Paulino en Donoso Cortés (II) / Alberto Caturelli – Notas y comentarios -- Bibliografía
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Contenido: Editorial – Perspectivas del Derecho del Trabajo / Jorge Rodríguez Mancini – Conciliación laboral / Santiago A. Zarza – Modificaciones introducidas al régimen remuneratorio por la ley 24.700 / Liliana Hebe Litterio – Pago de la remuneración mediante depósito bancario / Liliana Hebe Litterio – Régimen de asignaciones familiares / José B. Gómez Paz – Trabajo humano y retribución justa / Mario F. Vivino – La reforma laboral según la Ley 25.013 / Juan Manuel Arias – Reflexiones contemporáneas: Presentación – La filosofía de la guerra y la paz más allá de las tres “tradiciones” / Hernando V. Cañardo – Democracia, modernidad y cristianismo / Philippe Benetón – Derechas e izquierdas en el pensamiento político contemporáneo / Dalmacio Negro Pavón – El mercado común del cono sur - Mercosur / Fernando P. Brebbia – Integración sudamericana y derecho / Francisco Arias Pellerano – Discurso televisivo y discurso judicial / Luis María Bandieri – Recensiones – Anexo legislativo
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Contenido: Nota preliminar – La transcripción de textos incluídos en los primeros impresos castellanos: algunos problemas aún sin resolver /Lilia E. Ferrario de Orduna – Símbolos “primarios” y relato “ mítico” según Paul Ricoeur en el “Libro de Buen Amor” / Sofía M. Carrizo Rueda – Adán de San Víctor y las sequentiae en las “Cantigas de Santa María” del Rey Sabio / Santiago Disalvo – Andanzas por la sierra en el “Libro de Buen Amor” / Lía Noemí Uriarte Rebaudi – Obras menores en cuaderna vía: esbozo de un panorama para el siglo XIV / María Cristina Balestrini – Algunas cuestiones vinculadas con el “Libro de Séneca hordenado e dispuesto contra la yra e saña”: fecha de composición, traductor e intencionalidad / Juan Héctor Fuentes – Legitimación y consejo en “Castigos e documentos” del rey Sancho IV / Diana Leila Albornoz – Las veinte primeras coplas del “Rimado de Palacio”: la construcción de una voz confesante / Lorena Edith Pacheco ; Gloria Edith Siracusa – Nájera en Ayala: doctrina y discurso / Jorge N. Ferro – Adiciones unitarias a la versión primitiva de las crónicas de Pero López de Ayala / José Luis Moure – Estructura y estilo del “Tratado del Aojamiento” / Lidia Beatriz Ciapparelli – Consideraciones sobre las virtudes en Mosén Diego de Valera / Hugo Roberto Basualdo Miranda ; María del Carmen Maurín ; Ángel Alfredo Atencio Santander – La historia del mago Merlín desde la perspectiva demonológica de la Baja Edad Media / Mónica Nasif – Evolución del topos constantinopolitano en los libros de caballerías: el caso de “Cirongilio de Tracia” de Bernardo de Vargas / Javier Roberto González – Las doncellas seductoras en los libros de caballerías españoles / María del Rosario Aguilar – Los procedimientos jurídico-deliberativos en el “Amadís de Gaula” / Silvia Cristina Lastra Paz – La imagen del moro en la “Leyenda de los infantes de Lara” / Irene Zaderenko – La finalidad del “Libro de Apolonio” / Carlos Crida – La estructura narrativa de las “Mocedades de Rodrigo” / Leonardo Funes – Edición crítica del manuscrito escurialense M-III-7 (Libro de las maravillas del mundo, de Juan de Mandevilla). Problemas y respuestas / María Mercedes Rodríguez
O perfil dos parlamentares da Câmara dos Deputados : quadro comparativo da 48ª com a 52ª Legislatura
Resumo:
Apresenta um estudo comparativo da Legislatura de 1987 e de 2003 da Câmara dos Deputados Federal, tomando como ponto de partida o levantamento de dados das duas legislaturas citadas. Utiliza-se especificamente o indicador da profissão de cada parlamentar eleito e também dos parlamentares suplentes que ingressaram no decorrer das referidas legislaturas. Objetiva verificar como está a representação dos cidadãos na Câmara dos Deputados, se a Câmara no decorrer de doze anos está mais popular ou mais elitista. Apresenta ainda a discussão a respeito da democracia no Brasil feita por Norberto Bobbio e também a reflexão de Anthony Downs sobre a incerteza do eleitor no momento de escolha seus representantes. Contribui para o entendimento de como o sistema político brasileiro sofre alterações ao longo do tempo.
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Misconceptions, Outright Prejudice - Fishing rights. The Dilemma of the Nile Perch - Africa: Ecolabelling. Fishing Safely - Analysis: Safety at Sea. Shoring Up - Labour: Shore-based Workers. A Sustainable, Equitable, Small-scale Fisheries - Document: Traditional Communities. Getting Their Act Together - India: Co-management. Certifying the Uncertifiable? - Report: Industrial Aquaculture. Shocking Reality - Cambodia: Electro-fishing. Be Consultative, Participatory - Document: Indigenous Peoples. Towing the Line - Peru: Artisanal Shark Fishery. Declaration of Charter. (56 pp.)
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Rui de Oliveira Barbosa, jurisconsulto e estadista, nasceu em Salvador, em 1849, e morreu em Petrópolis, Rio de Janeiro, em 1923. Iniciou o curso de Direito na Faculdade do Recife, em 1866, concluindo-se na Faculdade de Direito de São Paulo, em 1870. Entusiasta da campanha abolicionista, escreveu artigos, ainda como estudante, no jornal o Radical Paulistano e no Diário da Bahia. Elegeu-se deputado-geral pela Bahia, em 1878. Destacando-se nas discussões sobre as eleições diretas, abolição da escravatura e reforma do ensino. Com a Proclamação da República, foi nomeado Ministro da Fazenda do Governo Provisório e Vice-Presidente da República, quando defendeu a primeira Constituição da República na imprensa e no Parlamento. Em 1891, foi eleito Senador pela Bahia, mandato que desempenhou até sua morte, em 1923. Rui Barbosa foi autor dos decretos da proclamação da Bandeira Nacional, da liberdade de cultos e de tantos outros que estruturaram as instituições democráticas brasileiras. Em 1907, chefiou a delegação do Brasil à II Conferência da Paz, em Haia, onde defendeu o princípio da igualdade entre as nações. Sócio fundador da Academia Brasileira de Letras, foi eleito seu presidente, cargo que ocupou até 1919. Rui Barbosa não foi apenas notável como jurisconsulto, mas também como orador, conferencista, jornalista e escritor. Sendo considerado, hoje, um dos grandes clássicos da língua portuguesa. Projecto n. 48... de julho de 1884, traz, na íntegra, o projeto de lei, do qual Rui Barbosa foi relator, que objetivava abolir a escravatura no Brasil, mas que foi rejeitado pela Câmara dos Deputados. De acordo com Sacramento Blake, esse projeto foi publicado no Diário Oficial e depois em outra fontes da Corte.
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Começou a ser distribuído hoje o parecer do relator Bernardo Cabral às duas mil emendas apresentadas ao projeto de Constituição. O relator deu parecer a favor de 30% das emendas, rejeitando a maioria. As emendas com 280 assinaturas nem sempre receberam parecer favorável, mas foram todas acolhidas. De acordo com o novo Regimento, o parecer do Relator tem importância secundária, porque todos os artigos terão que ser votados no Plenário. Caso a emenda não tenha sido aprovada pelo relator, o constituinte pode apresentar um destaque para que o assunto volte a análise de todos os constituintes. Constituintes fazem um gráfico em que evidencia os assuntos consensuais. A partir de amanhã começa a faze do pedido de destaque. Os constituintes terão até a segunda feira, às 6 da tarde para apresentar os seus pedidos. Cada constituinte tem direito a 6 destaques. O destaque para votação em separado precisa de 187 assinaturas. As matérias da Ordem econômica e da Ordem social, receberá atenção especial. Constituintes encontram dificuldades diante das restrições do Regimento.