9,957 research outputs found

    Analysis of the velocity field of granular hopper flow

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    We report the analysis of radial characteristics of the flow of granular material through a conical hopper. The discharge is simulated for various orifice sizes and hopper opening angles. Velocity profiles are measured along two radial lines from the hopper cone vertex: along the main axis of the cone and along its wall. An approximate power law dependence on the distance from the orifice is observed for both profiles, although differences between them can be noted. In order to quantify these differences, we propose a Local Mass Flow index that is a promising tool in the direction of a more reliable classification of the flow regimes in hoppers

    Edible coatings from galactomannans and their application to tropical fruits

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    Edible coatings play an important role in the quality and in the resistance to transportation, storage and display of a wide range of fresh and processed foods. Polysaccharide coatings with an oil-free appearance and low caloric content can be used to increase the shelf life of fresh fruits, since they allow the modification of the internal gas composition of fruits, retarding their senescence. The objective of this work was to study the ability of seed galactomannans, with different manose:galactose relation, from the Leguminosae Caesalpinea pulcherrima (2.8:1) and Adenanthera pavonina (2:1) as coatings to extend the shelf life of acerola (Malpighia emarginata), cajá (Spondias lutea), mango (Mangifera indica), pitanga (Eugenia uniflora) and sirigüela (Spondias purpurea). Fresh fruits surface properties, galactomannans relative viscosity as well as the wetting capacity of the coatings were determined. Galactomannans were obtained from seed endosperm and their toxicological safety was determined by oral administration to Wistar adult rats. No toxic effects were detected. Blends with different galactomannan:glycerol proportions were tested as coatings. The blends wettability was determined by the spreading coefficient using the sessile-drop method. The best proportions of galactomannan/glycerol were determined for coatings of C.pulcherrima and A.pavonina in the various fruits tested.Fundação para a Ciência e a Tecnologia (FCT) ; Alfa-Valnatura; CNPq; CAPES; FUNCAP.Alfa-Valnatur

    Analysis of parameter-independent PLLs with bang-bang phase-detectors

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    The parameter-independent design of Phase-Locked Loops (PLLs) is investigated for the case that a bang-bang phase-detector is used. Two self-biased CMOS PLL structures are proposed and compared, one l eading to a completely parameter- and frequency independent behavior. If the PLL frequency operation is constant and known in advance, however, both structures can be made independent of the transisto r Vt and b parameters

    Obtenção de adultos e aspectos biológicos da broca-do-mamoeiro, Pseudopiazurus obesus (GOHEMAN, 1838) (Coleoptera: Curculionidade).

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    bitstream/CPATC/19910/1/bp-32.pd

    Protein intake and obesity in schoolchildren

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    [resumo]Resumo de comunicação apresentada em: 16th European Congress on Obesity - ECO 2008; 2008 Mai 14-17; Genebra, Suíça

    Spin-phonon coupling in multiferroic RCrO3_3 (R-Y, Lu, Gd, Eu, Sm): A Raman study

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    Raman study on a select few orthochromites, RCrO3_3 (R = Y, Lu, Gd, Eu and Sm) shows that the phonon behavior at TN in compounds with magnetic R-ion (Gd and Sm) is remarkably different from that of non-magnetic R-ion (Y, Lu and Eu). While anomalies in most of the observed phonon frequencies in all these compounds may result from the distortion of CrO6_6 octahedra due to size effect and magnetostriction arising from Cr-ordering, the anomalous behavior of their linewidths observed at TN for the compounds with only magnetic R-ion suggests spin-phonon coupling. The presence of spin-phonon coupling and the anomalies in the low frequency modes related to R-ion motion in orthochromites (R = Gd and Sm) support the suggestion that the coupling between 4f-3d moments play important role in inducing switchable electric polarization.Comment: 6 pages (two column format), 7 figures; The updated version of the manuscript can be found at Euro. Phys. Lett. 101, 17008 (2013

    Structural and insulator-to-metal phase transition at 50 GPa in GdMnO3

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    We present a study of the effect of very high pressure on the orthorhombic perovskite GdMnO3 by Raman spectroscopy and synchrotron x-ray diffraction up to 53.2 GPa. The experimental results yield a structural and insulator-to-metal phase transition close to 50 GPa, from an orthorhombic to a metrically cubic structure. The phase transition is of first order with a pressure hysteresis of about 6 GPa. The observed behavior under very high pressure might well be a general feature in rare-earth manganites.Comment: 4 pages, 3 figures and 2 table
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