3,795 research outputs found
Global diffeomorphism of the Lagrangian flow-map defining Equatorially trapped water waves
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
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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High-angular resolution observations of methanol in the infrared dark cloud core G11.11-0.12P1
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
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
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
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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