3,397 research outputs found

    Utilizacao de materiais flutuantes no controle da evaporacao no Tropico Semi-Arido (TSA).

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    Materiais flutuantes foram testados em tanques tipo Classe A, com o objetivo de reduzir as perdas por evaporacao das superficies livres d'agua. As coberturas consistiram de discos impoermaveis compostos de vermiculita, parafina e cera de carnauba (Copernicia cerifera Mart.); esferas de barro vitrificadas; esferas de barro nao vitrificadas; e discos de isopor impreganados de uma mistura de cera de carnauba mais parafina derretida. Cada tratamento cobriu 80% da superficie exposta do tanque, apresentando os seguintes resultados no controle das perdas: 54%, 60%, 50% e 61% respectivamente. A eficiencia apresentada indicou que as coberturas empregadas poderao ser viaveis

    A nearly cylindrically symmetric source in the Brans-Dicke gravity as the generator of the rotational curves of the galaxies

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    Observation shows that the velocities of stars grow by approximately 2 to 3 orders of magnitude when the distances from the centers of the galaxies are in the range of 0.50.5 kpc to 82.382.3 kpc, before they begin to tend to a constant value. Up to know, the reason for this behavior is still a matter for debate. In this work, we propose a model which adequately describes this unusual behavior using a (nearly) cylindrical symmetrical solution in the framework of a scalar-tensor-like (the Brans-Dicke model) theory of gravity.Comment: 24 pages, 4 figures, accepted for publication in Eur. Phys. J.

    Determination of metabolite profiles in tropical wines by 1H NMR spectroscopy and chemometrics.

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    The aim of this work was to determine metabolite profiles of tropical wines produced in northeast Brazil, by using 1H NMR spectroscopy in comoination with chemometric methods to analyze and discrirninate wine samples from 2007 vintages produced by different wineries

    Raleamento de frutos de goiabeira cv. rica em Juazeiro, BA, Brasil.

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    Com o objetivo de determinar o numero de frutos de goiabeira (Psidium guajava L.), por planta, tendo em vista a colheita de frutos de melhor qualidade, para consumo in natura, foi desenvolvido um estudo, com a cultivar Rica, num delineamento de blocos ao acaso, com cinco tratamentos (plantas em raleio e com 200, 300, 400 e 500 frutos), em cinco repeticoes. Foram utilizadas tres plantas uteis por parcela, nas quais se observou: producao por planta (kg), produtividade (t/ha) e peso medio do fruto (g). A maior producao (76,5 kg) e a maior produtividade foram obtidas quando se conduziu a planta com 500 frutos/safra; os maiores idices de raleamento proporcionaram aumento significativo no peso medio dos frutos classificados como de primeira (acima de 120 g)

    Multi-layered Scaffolds Production via Fused Deposition Modeling (FDM) Using an Open Source 3D Printer: Process Parameters Optimization for Dimensional Accuracy and Design Reproducibility

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    Abstract One of the most applied strategies in tissue engineering consists in the development of 3D porous scaffolds with similar composition to the specific tissue. In fact, the microstructure of the scaffolds influences the final structure of the in growing tissue. In this study, multi-layered PCL scaffolds were produced with modified Fab@home FDM printer in order to analyze the influence of the extrusion technology (filament or powder extrusion head) and of the process parameters on the deposited material. In particular, dimensions and uniformity of both deposited filament and grid of the scaffolds were analyzed to understand the influence of the process parameters so as to optimize the FDM production technology

    Detection of electronic nematicity using scanning tunneling microscopy

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    Electronic nematic phases have been proposed to occur in various correlated electron systems and were recently claimed to have been detected in scanning tunneling microscopy (STM) conductance maps of the pseudogap states of the cuprate high-temperature superconductor Bi2Sr2CaCu2O8+x (Bi-2212). We investigate the influence of anisotropic STM tip structures on such measurements and establish, with a model calculation, the presence of a tunneling interference effect within an STM junction that induces energy-dependent symmetry-breaking features in the conductance maps. We experimentally confirm this phenomenon on different correlated electron systems, including measurements in the pseudogap state of Bi-2212, showing that the apparent nematic behavior of the imaged crystal lattice is likely not due to nematic order but is related to how a realistic STM tip probes the band structure of a material. We further establish that this interference effect can be used as a sensitive probe of changes in the momentum structure of the sample's quasiparticles as a function of energy.Comment: Accepted for publication (PRB - Rapid Communications). Main text (5 pages, 4 figures) + Supplemental Material (4 pages, 4 figures

    Enraizamento in vitro de Inhame da Costa (Dioscorea rotundata).

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    Com o objetivo de otimizar o meio de cultura para promover o enraizamento de plantas de inhame in vitro, microestacas de plantas de Inhame da Costa (Dioscorea rotundata) pré-estabelecidas in vitro foram utilizadas como fonte de explantes iniciais e cultivadas em meios de cultura com diferentes concentrações de sais e vitaminas do MS e doses de carvão ativado. Aos 30 dias, avaliaram-se as seguintes variáveis: altura de planta, número de folhas e de raízes. A utilização do meio ½ MS com 1,0 g de carvão ativado promoveu um melhor desenvolvimento (maior altura e maior número de folhas) das plantas de inhame. Quando se comparou os diferentes tipos de meio, o meio ½ MS também foi o mais adequado para promover o enraizamento das plantas de inhame in vitro utilizando 0,5 ou 1g L-1 de carvão ativado
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