393 research outputs found

    Multihierarchical electrodes based on titanate nanotubes and zinc oxide nanorods for photoelectrochemical water splitting

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    Studies involving water splitting to form hydrogen and oxygen have attracted attention because H2 is considered the fuel of the future. Photoelectrocatalysts have been widely used for this application, and several metal oxides can be applied as catalysts. Among them, we highlight zinc oxide nanorods (ZnONRs) and titanate nanotubes (TiNTs); however, their individual nanostructures exhibit disadvantages. For example, ZnONR shows rapid recombination of the photogenerated charges, and TiNT gives rise to randomly orientated films; these disadvantages limit their application as photoanodes. In this study, for the first time, we present a new class of multihierarchical electrodes based on TiNT-decorated ZnONR films that exhibited superior results to the individual species. The TiNTs are homogenously dispersed over the surface of the rods without forming agglomerates, giving rise to a heterojunction that exhibits lower recombination rates. It was found that the results are better when the contents of TiNT in the electrode are higher; thus, glycine was successfully used as a bridge to link both of the structures, increasing the amount of TiNT decorating the rods. As a result, the photocurrent generated with these multihierarchical electrodes is higher than that obtained for pure ZnONR electrodes (0.9 mA and 0.45 mA, respectively), and the electrode potentials for O2 evolution is lower than that observed for pure TiNT electrodes (0 V and 0.8 V vs. ERHE, respectively). The IPCE values are also higher for the multihierarchical electrodes

    Inquérito Sobre A Funcionalidade Do Joelho Em Mulheres Praticantes De Bodypum™

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    This study aimed to examine the knee functionality exclusively BODYPUMP ™ practitioners women. 40 women were evaluated. The investigation of knee functionality was through the Cincinatti adapted questionnaire, which varies from 0 to 100 scores, and the closer to 100, more functional knee. In general, women had a median score of 88.5 of knee functionality. It was also found that most women did not have falseio knee (60%) showed no limitation to perform the walk (65%) and stairs (60%). It was observed that 45% of women reported no limitation for the race and, for the jumps and spins; most women did not have limitation (37.5%) or had mild disability (30%). Most women reported that they do not feel pain during the BODYPUMP ™ exercises (52.5%), however, 45% reported pain during the execution of the squat and sink in this mode. There was a significant difference (p> 0.05) in the comparison of the knee of BODYPUMP ™ practitioners women functionality due to the practice time, indicating that women who practice this sport for more than five years had higher scores, ie better knee functionality when compared to women practitioners between three months and one year (p = 0.048). It is concluded that BODYPUMP ™ practitioner's women have good functionality of the knee, considered the highest score of the instrument used.40219920

    A interface percepção ambiental e geomorfologia no estudo da praia de Caúra em São José de Ribamar-MA

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    A interface percepção ambiental e geomorfologia noestudo da praia de Caúra em São José de Ribamar-M

    Some exact solutions of F(R) gravity with charged (a)dS black hole interpretation

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    In this paper we obtain topological static solutions of some kind of pure F(R)F(R) gravity. The present solutions are two kind: first type is uncharged solution which corresponds with the topological (a)dS Schwarzschild solution and second type has electric charge and is equivalent to the Einstein-Λ\Lambda-conformally invariant Maxwell solution. In other word, starting from pure gravity leads to (charged) Einstein-Λ\Lambda solutions which we interpreted them as (charged) (a)dS black hole solutions of pure F(R)F(R) gravity. Calculating the Ricci and Kreschmann scalars show that there is a curvature singularity at r=0r=0. We should note that the Kreschmann scalar of charged solutions goes to infinity as r0r \rightarrow 0, but with a rate slower than that of uncharged solutions.Comment: 21 pages, 4 figures, generalization to higher dimensions, references adde

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

    Search for W' bosons decaying to an electron and a neutrino with the D0 detector

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    This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let

    Measurement of the ratios of the Z/G* + >= n jet production cross sections to the total inclusive Z/G* cross section in ppbar collisions at sqrt(s) = 1.96 TeV

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    We present a study of events with Z bosons and jets produced at the Fermilab Tevatron Collider in ppbar collisions at a center of mass energy of 1.96 TeV. The data sample consists of nearly 14,000 Z/G* -> e+e- candidates corresponding to the integrated luminosity of 0.4 fb-1 collected using the D0 detector. Ratios of the Z/G* + >= n jet cross sections to the total inclusive Z/G* cross section have been measured for n = 1 to 4 jet events. Our measurements are found to be in good agreement with a next-to-leading order QCD calculation and with a tree-level QCD prediction with parton shower simulation and hadronization.Comment: 7 pages, 2 figures, slightly modified, submitted to Phys. Lett.
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