3,795 research outputs found

    Global diffeomorphism of the Lagrangian flow-map defining Equatorially trapped water waves

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    The aim of this paper is to prove that a three dimensional Lagrangian flow which defines equatorially trapped water waves is dynamically possible. This is achieved by applying a mixture of analytical and topological methods to prove that the nonlinear exact solution to the geophysical governing equations, derived by Constantin in J. Geophys. Res., 117 (2012), is a global diffeomorphism from the Lagrangian labelling variables to the fluid domain beneath the free surface

    A nonlocal two phase Stefan problem

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    We study a nonlocal version of the two-phase Stefan problem, which models a phase transition problem between two distinct phases evolving to distinct heat equations. Mathematically speaking, this consists in deriving a theory for sign-changing solutions of the equation, ut = J * v - v, v = {\Gamma}(u), where the monotone graph is given by {\Gamma}(s) = sign(s)(|s|-1)+ . We give general results of existence, uniqueness and comparison, in the spirit of [2]. Then we focus on the study of the asymptotic behaviour for sign-changing solutions, which present challenging difficulties due to the non-monotone evolution of each phase

    Young European Research Universities Network

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    Bring the young European research universities perspectiveto the EU debate. Strengthen joint research and teaching activities, maximise mobilityand collaborate on graduate employability. Promoting the implementation of Open Science at our member institutions

    High-angular resolution observations of methanol in the infrared dark cloud core G11.11-0.12P1

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    Recent studies suggest that infrared dark clouds (IRDCs) have the potential of harboring the earliest stages of massive star formation and indeed evidence for this is found toward distinct regions within them. We present a study with the Plateau de Bure Interferometer of a core in the archetypal filamentary IRDC G11.11-0.12 at few arcsecond resolution to determine its physical and chemical structure. The data consist of continuum and line observations covering the C34S 2-1 line and the methanol 2_k-1_k v_t=0 lines at 3mm and the methanol 5_k-4_k v_t =0 lines at 1mm. Our observations show extended emission in the continuum at 1 and 3 mm. The methanol 2_k-1_k v_t=0 emission presents three maxima extending over 1 pc scale (when merged with single-dish short-spacing observations); one of the maxima is spatially coincident with the continuum emission. The fitting results show enhanced methanol fractional abundance (~3x10^-8) at the central peak with respect to the other two peaks, where it decreases by about an order of magnitude (~4-6x10^-9). Evidence of extended 4.5 microns emission, "wings" in the CH3OH 2_k-1_k spectra, and CH3OH abundance enhancement point to the presence of an outflow in the East-West direction. In addition, we find a gradient of ~4 km/s in the same direction, which we interpret as being produced by an outflow(s)-cloud interaction.Comment: Accepted for publication to A&

    Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva

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    The paper is focused on elaboration of ZrO2 films on pure zirconium via anodizing inphosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. Thestructure and composition of the films were investigated using scanning electronicmicroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition ofthe oxides formed at both potentials can be identified as monoclinic ZrO2. In addition to Zrand O, the layers formed in phosphoric acid contain phosphorus originating from thephosphoric acid. When the phosphoric acid solution contains NaF, fluorine is alsoincorporated into the oxide layer. The oxides formed at a higher voltage have greaterroughness than those formed at 30 V. Anodized samples exhibit smaller current densitiesduring anodic polarization compared to the as-received zirconium covered with native oxide.Fil: Romonti, Daniela E.. Faculty of Applied Chemistry and Materials Science; RumaniaFil: Gomez Sanchez, Andrea Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Milošev, Ingrid. Jožef Stefan Institute; EsloveniaFil: Demetrescu, Ioana. Faculty of Applied Chemistry and Materials Science; RumaniaFil: Ceré, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

    Resistance to bleomycin increases the chronological life of cells

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    The identification of genes involved in chronological aging could have a potential utility as molecular markers in the chemotherapy treatment of cancer. The aim of this work is to study the relationship between the chronological aging and the resistance to Bleomycin for the purpose of establish the basic interactions between these phenomenons for further investigation of molecular markers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Effect of surface modification on the corrosion resistance of Zr 2.5Nb as material for permanent implants

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    Zirconium is a potential material for permanent implants. In particular, surface modification induced by anodisation has proved to be effective to improve corrosion resistance while keeping good osseointegration. The combination of zirconium with niobium is supposed to develop a structure that presents a high corrosion resistance and continues having the mechanical resistance necessary for implants. The aim of the present work is to determine the viability of using anodised Zr-2.5Nb as implant material, and compare it with pure Zr. Electrochemical tests performed in the anodizing solution and in a simulated biological solution revealed that by anodising the materials a higher corrosion resistance is obtained. The improvement on the corrosion resistance is particularly noticeable in the case of the pure metal after a short period immersed in the simulated biological solution. But, after a long period of immersion, the alloy shows better performance.Fil: Farina, Silvia Beatriz. Universidad Nacional de San Martín; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Unidad de Actividad de Materiales (CAC); ArgentinaFil: Gomez Sanchez, Andrea Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ceré, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin
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