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SPHYNX Publications

2016

 

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2017, 2016, 2015, 2014, 2013, 2012, Older publications (2008-2011)

 
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  • "The composition of nanogranitoids in migmatites overlying the Ronda peridotites (Betic Cordillera, S Spain): the anatectic history of a polymetamorphic basement"
  • A. Acosta-Vigil, A. Barich, O. Bartoli, C. J. Garrido, B. Cesare, L. Remusat, S. Poli and C. Raepsaet
    Contributions to Mineralogy and Petrology. 171(3):24 (March, 2016)
Abstract: The study of the composition of primary melts during anatexis of high-pressure granulitic migmatites is relevant to understand the generation and differentiation of continental crust. Peritectic minerals in migmatites can trap droplets of melt that forms via incongruent melting reactions during crustal anatexis. These melt inclusions commonly crystallize and form nanogranitoids upon slow cooling of the anatectic terrane. To obtain the primary compositions of crustal melts recorded in these nanogranitoids, including volatile concentrations and information on fluid regimes, they must be remelted and rehomogenized before analysis. A new occurrence of nanogranitoids was recently reported in garnets of mylonitic metapelitic gneisses (former high pressure granulitic migmatites) at the bottom of the prograde metamorphic sequence of Jubrique, located on top of the Ronda peridotite slab (Betic Cordillera, S Spain). Nanogranitoids within separated chips of cores and rims of large garnets from these migmatites were remelted at 15 kbar and 850, 825 or 800 degrees C and dry (without added H2O), during 24 h, using a piston cylinder apparatus. Although all experiments show glass (former melt) within melt inclusions, the extent of rehomogenization depends on the experimental temperature. Experiments at 850-825 degrees C show abundant disequilibrium microstructures, whereas those at 800 degrees C show a relatively high proportion of rehomogenized nanogranitoids, indicating that anatexis and entrapment of melt inclusions in these rocks likely occurred at pressures <= 1.5 GPa and temperatures close to 800 degrees C. Electron microprobe and NanoSIMS analyses show that experimental glasses are leucogranitoid and peraluminous, though define two distinct compositional groups. Type I melt inclusions correspond to K-rich, Ca- and H2O-poor leucogranitic melts, whereas type II melt inclusions represent K-poor, Ca- and H2O-rich granodioritic to tonalitic melts. Type I and II melt inclusions are found in most cases at the cores and rims of large garnets porphyroclasts, respectively. We tentatively interpret these two distinct melt compositions as suggesting that these former migmatites underwent two melting events under contrasting fluid regimes, possibly during two different orogenic periods. This study demonstrates the strong potential of melt inclusions studies in migmatites and granulites in order to unravel their anatectic history, particularly in strongly deformed rocks where most of the classical anatectic microstructures and macrostructures have been erased during deformation.
BibTeX:
@article{Acosta-Vigil2016,
  author = {Acosta-Vigil, Antonio and Barich, Amel and Bartoli, Omar and Garrido, Carlos J. and Cesare, Bernardo and Remusat, Laurent and Poli, Stefano and Raepsaet, Caroline},
  title = {The composition of nanogranitoids in migmatites overlying the Ronda peridotites (Betic Cordillera, S Spain): the anatectic history of a polymetamorphic basement},
  journal = {Contributions to Mineralogy and Petrology},
  year = {2016},
  volume = {171},
  number = {3},
  pages = {24},
  doi = {10.1007/s00410-016-1230-3}
}
  • "Fifth-order susceptibility unveils growth of thermodynamic amorphous order in glass-formers"
  • S. Albert, T. Bauer, M. Michl, G. Biroli, J. .. P. Bouchaud, A. Loidl, P. Lunkenheimer, R. Tourbot, C. Wiertel-Gasquet and F. Ladieu
    Science. 352(6291):1308-1311 (June, 2016)
Abstract: Glasses are ubiquitous in daily life and technology. However, the microscopic mechanisms generating this state of matter remain subject to debate: Glasses are considered either as merely hyperviscous liquids or as resulting from a genuine thermodynamic phase transition toward a rigid state. We showthat third-and fifth-order susceptibilities provide a definite answer to this long-standing controversy. Performing the corresponding high-precision nonlinear dielectric experiments for supercooled glycerol and propylene carbonate, we find strong support for theories based on thermodynamic amorphous order. Moreover, when lowering temperature, we find that the growing transient domains are compact-that is, their fractal dimension d(f) = 3. The glass transitionmay thus represent a class of critical phenomena different from canonical second-order phase transitions for which d(f) < 3.
BibTeX:
@article{Albert2016,
  author = {Albert, S. and Bauer, Th. and Michl, M. and Biroli, G. and Bouchaud, J. -. P. and Loidl, A. and Lunkenheimer, P. and Tourbot, R. and Wiertel-Gasquet, C. and Ladieu, F.},
  title = {Fifth-order susceptibility unveils growth of thermodynamic amorphous order in glass-formers},
  journal = {Science},
  year = {2016},
  volume = {352},
  number = {6291},
  pages = {1308--1311},
  doi = {10.1126/science.aaf3182}
}
  • "From network depolymerization to stress corrosion cracking in sodium-borosilicate glasses: Effect of the chemical composition"
  • M. Barlet, J.-M. Delaye, B. Boizot, D. Bonamy, R. Caraballo, S. Peuget and C. L. Rountree
    Journal of Non-crystalline Solids. 450:174-184 (October, 2016)
Abstract: The study herein examines how chemical composition impacts sub-critical stress corrosion cracking (SCC) in sodium borosilicate glasses. The crack speed versus stress intensity factor (v vs. K-I) curves were obtained for seven ternary SiO2-Na2O-B2O3 (SBN) glasses of selected chemical compositions. Na2O plays an interesting role in the SCC behavior. First, increasing the Na2O concentration yields an increase in the environmental limit (K-e). Second, increasing the Na2O concentration affects how fast SCC occurs as K-I increases (i.e. the slope in region I SCC). This second effect is highly nonlinear: it is insignificant for Na2O <20% but it becomes increasingly important above 20%, when sodium acts as a network modifier. Raman spectroscopy and Molecular Dynamics (MD) simulations aid in revealing the structural variations which arise from increasing concentrations of Na2O. Na2O causes the relative proportions of the different chemical bonds accessible in SBN glasses to vary. For this series of glasses, the Si-O-Si bond does not dominate the SCC properties. SCC variations originate in the mesoscale structure where sodium ions act as network modifiers on both the silica and borate units, thus yielding a partial depolymerization (i.e. a decrease in the reticulation level) of the network. This second effect reveals itself to be the one responsible for the SCC chemical dependency. Poisson's ratio increases approximately linearly with increasing Na2O concentration, and thus, it is also not simply proportional to the slope in region I SCC. Partial depolymerization of the glass provides a novel prospective on the controlling factors in the sub-critical crack growth. (C) 2016 Elsevier B.V. All rights reserved.
BibTeX:
@article{Barlet2016,
  author = {Barlet, Marina and Delaye, Jean-Marc and Boizot, Bruno and Bonamy, Daniel and Caraballo, Richard and Peuget, Sylvain and Rountree, Cindy L.},
  title = {From network depolymerization to stress corrosion cracking in sodium-borosilicate glasses: Effect of the chemical composition},
  journal = {Journal of Non-crystalline Solids},
  year = {2016},
  volume = {450},
  pages = {174--184},
  doi = {10.1016/j.jnoncrysol.2016.07.017}
}
Abstract: For reaction-diffusion processes with at most bimolecular reactants, we derive well-behaved, numerically tractable, exact Langevin equations that govern a stochastic variable related to the response field in field theory. Using duality relations, we show how the particle number and other quantities of interest can be computed. Our work clarifies long-standing conceptual issues encountered in field-theoretical approaches and paves the way for systematic numerical and theoretical analyses of reaction-diffusion problems.
BibTeX:
@article{Benitez2016,
  author = {Benitez, Federico and Duclut, Charlie and Chate, Hugues and Delamotte, Bertrand and Dornic, Ivan and Munoz, Miguel A.},
  title = {Langevin Equations for Reaction-Diffusion Processes},
  journal = {Physical Review Letters},
  year = {2016},
  volume = {117},
  number = {10},
  pages = {100601},
  doi = {10.1103/PhysRevLett.117.100601}
}
  • "A simple AC calorimeter for specific heat measurement of liquids confined in porous materials: A study of hydrated Vycor"
  • M. Bonetti and J.-M. Zanotti
    Review of Scientific Instruments. 87(9):094903 (September, 2016)
Abstract: Nanometric confinement of fluids in porous media is a classical way to stabilize metastable states. Calorimetric studies give insight on the behavior of confined liquids compared to bulk liquids. We have developed and built a simple quasi-adiabatic AC calorimeter for heat capacity measurement of confined liquids in porous media in a temperature range between 150 K and 360 K. Taking the fully hydrated porous medium as a reference, we address the thermal behavior of water as a monolayer on the surface of a porous silica glass (Vycor). For temperature ranging between 160 K and 325 K, this interfacial water shows a surprisingly large heat capacity. We describe the interfacial Hbond network in the framework of a mean field percolation model, to show that at 160 K interfacial water experiences a transformation from low density amorphous ice to a heterogeneous system where transient low and high density water patches coexist. The fraction of each species is controlled by the temperature. We identify the large entropy of the interfacial water molecules as the cause of this behaviour. Published by AIP Publishing.
BibTeX:
@article{Bonetti2016,
  author = {Bonetti, Marco and Zanotti, Jean-Marc},
  title = {A simple AC calorimeter for specific heat measurement of liquids confined in porous materials: A study of hydrated Vycor},
  journal = {Review of Scientific Instruments},
  year = {2016},
  volume = {87},
  number = {9},
  pages = {094903},
  doi = {10.1063/1.4963663}
}
  • "Pressure-Induced Glass Transition Probed via the Mobility of Coumarin 1 Fluorescent Molecule"
  • M. Bonetti
    Journal of Physical Chemistry B. 120(18):4319-4328 (May, 2016)
Abstract: The route to form a glass is generally achieved upon cooling where the slowing down might be interpreted as the trapping of molecules in potential wells. On the other hand, isothermal compression induces a glassy state by modifying the molecular packing ending in jamming. Here, we focus on how isothermal compression perturbs the mobility of a probe molecule in three different host liquids up to the pressure-induced glass transition. By use of the fluorescence recovery technique, the diffusion of the fluorescent molecule Coumarin 1 (Cl) is measured in poly(propylene glycol) (PPG-1000M and -2700M), in the fragile van der Waals propylene carbonate (PC), and in hydrogen-bonded methanol and ethanol. High pressures up to 6 GPa are obtained with a-diamond anvil cell. In PC at a pressure similar to 1.3 GPa close to the glass-transition pressure, the diffusion coefficient of Cl follows an Arrhenius behavior with an similar to 5 orders of magnitude increase of the diffusive time. No decoupling from the Stokes Einstein equation is noticed. A similar exponential behavior is measured in ethanol and methanol but extended to different pressure ranges up to 2.5 and 6.2 GPa, respectively. In PPG-1000M a decoupling from the Stokes Einstein relation is observed between 0.3 and 0.8 GPa that could be related to a modification of the interaction between polymer segments and the probe molecule. These results might indicate that interaction between probe and dynamic heterogeneities become less important under applied pressure, unlike in the temperature-induced glass transition.
BibTeX:
@article{Bonetti2016a,
  author = {Bonetti, Marco},
  title = {Pressure-Induced Glass Transition Probed via the Mobility of Coumarin 1 Fluorescent Molecule},
  journal = {Journal of Physical Chemistry B},
  year = {2016},
  volume = {120},
  number = {18},
  pages = {4319--4328},
  doi = {10.1021/acs.jpcb.6b02004}
}
  • "Observation of resonant interactions among surface gravity waves"
  • F. Bonnefoy, F. Haudin, G. Michel, B. Semin, T. Humbert, S. Aumaitre, M. Berhanu and E. Falcon
    Journal of Fluid Mechanics. 805:R3 (October, 2016)
Abstract: We experimentally study resonant interactions of oblique surface gravity waves in a large basin. Our results strongly extend previous experimental results performed mainly for perpendicular or collinear wave trains. We generate two oblique waves crossing at an acute angle, while we control their frequency ratio, steepnesses and directions. These mother waves mutually interact and give birth to a resonant wave whose properties (growth rate, resonant response curve and phase locking) are fully characterized. All our experimental results are found in good quantitative agreement with four-wave interaction theory with no fitting parameter. Off-resonance experiments are also reported and the relevant theoretical analysis is conducted and validated.
BibTeX:
@article{Bonnefoy2016,
  author = {Bonnefoy, F. and Haudin, F. and Michel, G. and Semin, B. and Humbert, T. and Aumaitre, S. and Berhanu, M. and Falcon, E.},
  title = {Observation of resonant interactions among surface gravity waves},
  journal = {Journal of Fluid Mechanics},
  year = {2016},
  volume = {805},
  pages = {R3},
  doi = {10.1017/jfm.2016.576}
}
  • "Modern and past volcanic degassing of iodine"
  • H. Bureau, A. .. L. Auzende, M. Marocchi, C. Raepsaet, P. Munsch, D. Testemale, M. Mezouar, S. Kubsky, M. Carriere, A. Ricolleau and G. Fiquet
    Geochimica Et Cosmochimica Acta. 173:114-125 (January, 2016)
Abstract: We have monitored iodine degassing from a melt to a water vapor during decompression (i.e. magma ascent). Experiments have been performed by combining diamond anvil cells experiments with synchrotron X-rays fluorescence analysis. Partition coefficients D-fluid/melt(I) measured for a pressure and temperature range of 0.1-1.8 GPa and 500-900 degrees C, range from 41 to 1.92, values for room conditions D-fluid/glass(I) (quenched samples) are equal to or higher than 350. We show that iodine degassing with water is earlier and much more efficient than for lighter halogen elements, Cl and Br. Iodine is totally degassed from the silicate melt at room conditions. By applying these results to modern volcanology, we calculate an annual iodine flux for subduction related volcanism of 0.16-2.4 kt yr(-1). We suggest that the natural iodine degassing may be underestimated, having possible consequences on the Earth's ozone destruction cycle. By applying this results to the Early Earth, we propose a process that may explain the contrasted signature of I, Br and Cl, strongly depleted in the bulk silicate Earth, the most depleted being iodine, whereas fluorine is almost enriched. The Earth may have lost heavy halogen elements during an early water degassing process from the magma ocean. (C) 2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Bureau2016,
  author = {Bureau, H. and Auzende, A. -. L. and Marocchi, M. and Raepsaet, C. and Munsch, P. and Testemale, D. and Mezouar, M. and Kubsky, S. and Carriere, M. and Ricolleau, A. and Fiquet, G.},
  title = {Modern and past volcanic degassing of iodine},
  journal = {Geochimica Et Cosmochimica Acta},
  year = {2016},
  volume = {173},
  pages = {114--125},
  doi = {10.1016/j.gca.2015.10.017}
}
  • "Turbulent drag in a rotating frame"
  • A. Campagne, N. Machicoane, B. Gallet, P.-P. Cortet and F. Moisy
    Journal of Fluid Mechanics. 794:R5 (May, 2016)
Abstract: What is the turbulent drag force experienced by an object moving in a rotating fluid? This open and fundamental question can be addressed by measuring the torque needed to drive an impeller at a constant angular velocity ! in a water tank mounted on a platform rotating at a rate Omega. We report a dramatic reduction in drag as Omega increases, down to values as low as 12% of the non-rotating drag. At small Rossby number Ro = omega/Omega, the decrease in the drag coefficient K follows the approximate scaling law K similar to Ro, which is predicted in the framework of nonlinear inertial-wave interactions and weak-turbulence theory. However, stereoscopic particle image velocimetry measurements indicate that this drag reduction instead originates from a weakening of the turbulence intensity in line with the two-dimensionalization of the large-scale flow.
BibTeX:
@article{Campagne2016,
  author = {Campagne, Antoine and Machicoane, Nathanael and Gallet, Basile and Cortet, Pierre-Philippe and Moisy, Frederic},
  title = {Turbulent drag in a rotating frame},
  journal = {Journal of Fluid Mechanics},
  year = {2016},
  volume = {794},
  pages = {R5},
  doi = {10.1017/jfm.2016.214}
}
  • "Estimating the Dimension of an Inertial Manifold from Unstable Periodic Orbits"
  • X. Ding, H. Chate, P. Cvitanovic, E. Siminos and K. A. Takeuchi
    Physical Review Letters. 117(2):024101 (July, 2016)
Abstract: We provide numerical evidence that a finite-dimensional inertial manifold on which the dynamics of a chaotic dissipative dynamical system lives can be constructed solely from the knowledge of a set of unstable periodic orbits. In particular, we determine the dimension of the inertial manifold for the Kuramoto-Sivashinsky system and find it to be equal to the "physical dimension" computed previously via the hyperbolicity properties of covariant Lyapunov vectors.
BibTeX:
@article{Ding2016,
  author = {Ding, X. and Chate, H. and Cvitanovic, P. and Siminos, E. and Takeuchi, K. A.},
  title = {Estimating the Dimension of an Inertial Manifold from Unstable Periodic Orbits},
  journal = {Physical Review Letters},
  year = {2016},
  volume = {117},
  number = {2},
  pages = {024101},
  doi = {10.1103/PhysRevLett.117.024101}
}
  • "The switching between zonal and blocked mid-latitude atmospheric circulation: a dynamical system perspective"
  • D. Faranda, G. Masato, N. Moloney, Y. Sato, F. Daviaud, B. Dubrulle and P. Yiou
    Climate Dynamics. 47(5-6):1587-1599 (September, 2016)
Abstract: Atmospheric mid-latitude circulation is dominated by a zonal, westerly flow. Such a flow is generally symmetric, but it can be occasionally broken up by blocking anticyclones. The subsequent asymmetric flow can persist for several days. In this paper, we apply new mathematical tools based on the computation of an extremal index in order to reexamine the dynamical mechanisms responsible for the transitions between zonal and blocked flows. We discard the claim that mid-latitude circulation features two distinct stable equilibria or chaotic regimes, in favor of a simpler mechanism that is well understood in dynamical systems theory: we identify the blocked flow as an unstable fixed point (or saddle point) of a single basin chaotic attractor, dominated by the westerlies regime. We also analyze the North Atlantic Oscillation and the Arctic Oscillation atmospheric indices, whose behavior is often associated with the transition between the two circulation regimes, and investigate analogies and differences with the bidimensional blocking indices. We find that the Arctic Oscillation index, which can be thought as a proxy for a hemispheric average of the Tibaldi-Molteni blocking index, tracks unstable fixed points. On the other hand, the North Atlantic Oscillation, representative only for local properties of the North Atlantic blocking dynamics, does not show any trace of the presence of unstable fixed points of the dynamics.
BibTeX:
@article{Faranda2016,
  author = {Faranda, Davide and Masato, Giacomo and Moloney, Nicholas and Sato, Yuzuru and Daviaud, Francois and Dubrulle, Berengere and Yiou, Pascal},
  title = {The switching between zonal and blocked mid-latitude atmospheric circulation: a dynamical system perspective},
  journal = {Climate Dynamics},
  year = {2016},
  volume = {47},
  number = {5-6},
  pages = {1587--1599},
  doi = {10.1007/s00382-015-2921-6}
}
  • "Evaporation-driven dewetting of a liquid film"
  • L. Fourgeaud, E. Ercolani, J. Duplat, P. Gully and V. S. Nikolayev
    Phys. Rev. Fluids. 1:041901 (Aug, 2016)
    American Physical Society.
BibTeX:
@article{Fourgeaud2016,
  author = {Fourgeaud, L. and Ercolani, E. and Duplat, J. and Gully, P. and Nikolayev, V. S.},
  title = {Evaporation-driven dewetting of a liquid film},
  journal = {Phys. Rev. Fluids},
  publisher = {American Physical Society},
  year = {2016},
  volume = {1},
  pages = {041901},
  url = {http://link.aps.org/doi/10.1103/PhysRevFluids.1.041901},
  doi = {10.1103/PhysRevFluids.1.041901}
}
Abstract: We present an experimental study of the statistical properties of millimeter-size spheres floating on the surface of a turbulent flow. The flow is generated in a layer of liquid metal by an electromagnetic forcing. By using two magnet arrays, we are able to create one highly fluctuating flow and another, more stationary flow. In both cases, we follow the motion of hundreds of particles floating at the deformed interface of the liquid metal. We evidence the clustering of floaters by a statistical study of the local concentration of particles. Some dynamical properties of clusters are exposed. We perform spatial correlations between particle concentration and hydrodynamical quantities linked with inertial effects; with vortical motion, and with horizontal divergence (corresponding to compressibility in the surface). From comparing these correlations, we propose the so-called surface compressibility as the main clustering mechanism in our system. Hence, although floaters are not passive scalar and move on a deformed surface, the scenario is similar to the one reported for passive scalar on an almost flat free surface of a turbulent flow. (C) 2016 Elsevier Masson SAS. All rights reserved.
BibTeX:
@article{Gutierrez2016,
  author = {Gutierrez, Pablo and Aumaitre, Sebastien},
  title = {Clustering of floaters on the free surface of a turbulent flow: An experimental study},
  journal = {European Journal of Mechanics B-fluids},
  year = {2016},
  volume = {60},
  pages = {24--32},
  doi = {10.1016/j.euromechflu.2016.06.009}
}
Abstract: We study the propagation of monochromatic surface waves on a turbulent flow of liquid metal, when the waves are much less energetic than the background flow. Electromagnetic forcing drives quasi-two-dimensional turbulence with strong vertical vorticity. To isolate the surface-wave field, we remove the surface deformation induced by the background turbulent flow using coherent-phase averaging at the wave frequency. We observe a significant increase in wavelength, when the latter is smaller than the forcing length scale. This phenomenon has not been reported before and can be explained by multiple random wave deflections induced by the turbulent velocity gradients. The shift in wavelength thus provides an estimate of the fluctuations in deflection angle. Local measurements of the wave frequency far from the wavemaker do not reveal such systematic behavior, although a small shift is visible. Finally, we quantify the damping enhancement induced by the turbulent flow and compare it to the existing theoretical predictions. Most of them suggest that the damping increases as the square of the Froude number, whereas our experimental data show a linear increase with the Froude number. We interpret this linear relationship as a balance between the time for a wave to cross a turbulent structure and the turbulent mixing time. The larger the ratio of these two times, the more energy is extracted from the wave. We conclude with possible mechanisms for energy exchange. (C) 2016 AIP Publishing LLC.
BibTeX:
@article{Gutierrez2016a,
  author = {Gutierrez, Pablo and Aumaitre, Sebastien},
  title = {Surface waves propagating on a turbulent flow},
  journal = {Physics of Fluids},
  year = {2016},
  volume = {28},
  number = {2},
  pages = {025107},
  doi = {10.1063/1.4941425}
}
  • "Measurements of Surface Deformation in Highly-Reflecting Liquid-Metals"
  • P. Gutierrez, V. Padilla and S. Aumaitre
    Nonlinear Dynamics: Materials, Theory and Experiments. 173:233-245 (2016)
Abstract: We present an experimental study of surface deformation in a liquid metal. The investigation has two main parts. First we present an optical setup allowing to obtain the surface profile along a line, for a highly-reflecting liquid-metal. We track the diffusion of a laser sheet on the surface from two opposite angles, avoiding saturations due to specular reflection. In the second part, the technique is used to study some aspects of thewave-vortex interaction problem. Special attention is given to the surface deformation produced by a flow composed by moving vortices. Asymmetric height statistics are observed and discussed. Some indications of wave emission are presented. Finally, the attenuation of propagating waves by the same flow is briefly discussed.
BibTeX:
@article{Gutierrez2016b,
  author = {Gutierrez, Pablo and Padilla, Vincent and Aumaitre, Sebastien},
  title = {Measurements of Surface Deformation in Highly-Reflecting Liquid-Metals},
  journal = {Nonlinear Dynamics: Materials, Theory and Experiments},
  year = {2016},
  volume = {173},
  pages = {233--245},
  doi = {10.1007/978-3-319-24871-4_18}
}
  • "Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate"
  • G. F. Nataf, P. Grysan, M. Guennou, J. Kreisel, D. Martinotti, C. L. Rountree, C. Mathieu and N. Barrett
    Scientific Reports. 6:33098 (September, 2016)
Abstract: The understanding of domain structures, specifically domain walls, currently attracts a significant attention in the field of (multi)-ferroic materials. In this article, we analyze contrast formation in full field electron microscopy applied to domains and domain walls in the uniaxial ferroelectric lithium niobate, which presents a large 3.8 eV band gap and for which conductive domain walls have been reported. We show that the transition from Mirror Electron Microscopy (MEM - electrons reflected) to Low Energy Electron Microscopy (LEEM - electrons backscattered) gives rise to a robust contrast between domains with upwards (P-up) and downwards (P-down) polarization, and provides a measure of the difference in surface potential between the domains. We demonstrate that out-of-focus conditions of imaging produce contrast inversion, due to image distortion induced by charged surfaces, and also carry information on the polarization direction in the domains. Finally, we show that the intensity profile at domain walls provides experimental evidence for a local stray, lateral electric field.
BibTeX:
@article{Nataf2016,
  author = {Nataf, G. F. and Grysan, P. and Guennou, M. and Kreisel, J. and Martinotti, D. and Rountree, C. L. and Mathieu, C. and Barrett, N.},
  title = {Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate},
  journal = {Scientific Reports},
  year = {2016},
  volume = {6},
  pages = {33098},
  doi = {10.1038/srep33098}
}
Abstract: The oscillation inception in the single-branch pulsating heat pipe (PHP, called also oscillating heat pipe) has been studied in the presence of the heat conduction along the PHP tube, with the imposed both evaporator heat power and condenser temperature. A start-up regime caused rather by the meniscus/film evaporation than boiling has been considered. The dynamic equilibrium system state has been analyzed, where the liquid film is absent and the meniscus is located at a position where the tube temperature corresponds to the saturation temperature. The temporal evolution of the system responding to an initial fluctuation shows a non-linear response even for small fluctuations. The stability of the equilibrium state has been analyzed. The stability threshold corresponds to the start-up criterion. The main result of the above analysis is the independence of the start-up criterion of the liquid film properties (film shape and thickness). This result applies to the multi-branch PHP too. Due to the large tube thermal inertia, influence of the temporal variation of the tube temperature on the threshold can be neglected; only the equilibrium spatial temperature distribution along the tube matters. The start-up threshold value is determined for the temperature gradient along the tube, more specifically, its equilibrium value at the equilibrium meniscus location. It depends only weakly on other system parameters like condenser temperature or adiabatic section length. An analytical expression for the threshold has been obtained. The start-up power scales like square root of the tube heat conductivity. The liquid viscous dissipation is found to be much less important than the energy dissipation via the fluid and solid heat transfer. (C) 2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Nikolayev2016,
  author = {Nikolayev, Vadim S.},
  title = {Effect of tube heat conduction on the single branch pulsating heat pipe start-up},
  journal = {International Journal of Heat and Mass Transfer},
  year = {2016},
  volume = {95},
  pages = {477--487},
  doi = {10.1016/j.ijheatmasstransfer.2015.12.016}
}
  • "Role of evaporation rate on the particle organization and crack patterns obtained by drying a colloidal layer"
  • K. Piroird, V. Lazarus, G. Gauthier, A. Lesaine, D. Bonamy and C. L. Rountree
    Epl. 113(3):38002 (February, 2016)
Abstract: A scientific hurdle in manufacturing solid films by drying colloidal layers is preventing them from fracturing. This paper examines how the drying rate of colloidal liquids influences the particle packing at the nanoscale in correlation with the crack patterns observed at the macroscale. Increasing the drying rate results in more ordered, denser solid structures, and the dried samples have more cracks. Yet, introducing a holding period (at a prescribed point) during the drying protocol results in a more disordered solid structure with significantly less cracks. To interpret these observations, this paper conjectures that a longer drying protocol favors the formation of aggregates. It is further argued that the number and size of the aggregates increase as the drying rate decreases. This results in the formation of a more disordered, porous film from the viewpoint of the particle packing, and a more resistant film, i.e. less cracks, from the macroscale viewpoint. Copyright (C) EPLA, 2016
BibTeX:
@article{Piroird2016,
  author = {Piroird, K. and Lazarus, V. and Gauthier, G. and Lesaine, A. and Bonamy, D. and Rountree, C. L.},
  title = {Role of evaporation rate on the particle organization and crack patterns obtained by drying a colloidal layer},
  journal = {Epl},
  year = {2016},
  volume = {113},
  number = {3},
  pages = {38002},
  doi = {10.1209/0295-5075/113/38002}
}
Abstract: Novel 'smectic-P' behavior, in which self-propelled particles form rows and move on average along them, occurs generically within the orientationally ordered phase of simple models that we simulate. Both apolar (head-tail symmetric) and polar (head-tail asymmetric) models with aligning and repulsive interactions exhibit slow algebraic decay of smectic order with system size up to some finite length scale, after which faster decay occurs. In the apolar case, this scale is that of an undulation instability of the rows. In the polar case, this instability is absent, but traveling fluctuations disrupt the rows in large systems and motion and smectic order may spontaneously globally rotate. These observations agree with a new hydrodynamic theory which we present here. Variants of our models also exhibit active smectic 'A' and 'C' order, with motion orthogonal and oblique to the layers respectively.
BibTeX:
@article{Romanczuk2016,
  author = {Romanczuk, Pawel and Chate, Hugues and Chen, Leiming and Ngo, Sandrine and Toner, John},
  title = {Emergent smectic order in simple active particle models},
  journal = {New Journal of Physics},
  year = {2016},
  volume = {18},
  pages = {063015},
  doi = {10.1088/1367-2630/18/6/063015}
}
  • "Experimental characterization of extreme events of inertial dissipation in a turbulent swirling flow."
  • E. .. W. Saw, D. Kuzzay, D. Faranda, A. Guittonneau, F. Daviaud, C. Wiertel-Gasquet, V. Padilla and B. Dubrulle
    Nature communications. 7:12466-12466 (August, 2016)
Abstract: The three-dimensional incompressible Navier-Stokes equations, which describe the motion of many fluids, are the cornerstones of many physical and engineering sciences. However, it is still unclear whether they are mathematically well posed, that is, whether their solutions remain regular over time or develop singularities. Even though it was shown that singularities, if exist, could only be rare events, they may induce additional energy dissipation by inertial means. Here, using measurements at the dissipative scale of an axisymmetric turbulent flow, we report estimates of such inertial energy dissipation and identify local events of extreme values. We characterize the topology of these extreme events and identify several main types. Most of them appear as fronts separating regions of distinct velocities, whereas events corresponding to focusing spirals, jets and cusps are also found. Our results highlight the non-triviality of turbulent flows at sub-Kolmogorov scales as possible footprints of singularities of the Navier-Stokes equation.
BibTeX:
@article{Saw2016,
  author = {Saw, E. -. W. and Kuzzay, D. and Faranda, D. and Guittonneau, A. and Daviaud, F. and Wiertel-Gasquet, C. and Padilla, V. and Dubrulle, B.},
  title = {Experimental characterization of extreme events of inertial dissipation in a turbulent swirling flow.},
  journal = {Nature communications},
  year = {2016},
  volume = {7},
  pages = {12466--12466},
  doi = {10.1038/ncomms12466}
}
Abstract: A bidimensional simulation of a sphere moving at constant velocity into a cloud of smaller spherical grains far from any boundaries and without gravity is presented with a non-smooth contact dynamics method. A dense granular "cluster" zone builds progressively around the moving sphere until a stationary regime appears with a constant upstream cluster size. The key point is that the upstream cluster size increases with the initial solid fraction phi(0) but the cluster packing fraction takes an about constant value independent of f0. Although the upstream cluster size around the moving sphere diverges when f0 approaches a critical value, the drag force exerted by the grains on the sphere does not. The detailed analysis of the local strain rate and local stress fields made in the non-parallel granular flow inside the cluster allows us to extract the local invariants of the two tensors: dilation rate, shear rate, pressure and shear stress. Despite different spatial variations of these invariants, the local friction coefficient mu appears to depend only on the local inertial number I as well as the local solid fraction, which means that a local rheology does exist in the present non-parallel flow. The key point is that the spatial variations of I inside the cluster do not depend on the sphere velocity and explore only a small range around the value one.
BibTeX:
@article{Seguin2016,
  author = {Seguin, A. and Lefebvre-Lepot, A. and Faure, S. and Gondret, P.},
  title = {Clustering and flow around a sphere moving into a grain cloud},
  journal = {European Physical Journal E},
  year = {2016},
  volume = {39},
  number = {6},
  pages = {63},
  doi = {10.1140/epje/i2016-16063-0}
}
  • "Local rheological measurements in the granular flow around an intruder"
  • A. Seguin, C. Coulais, F. Martinez, Y. Bertho and P. Gondret
    Physical Review E. 93(1):012904 (January, 2016)
Abstract: The rheological properties of granular matter within a two-dimensional flow around a moving disk is investigated experimentally. Using a combination of photoelastic and standard tessellation techniques, the strain and stress tensors are estimated at the grain scale in the time-averaged flow field around a large disk pulled at constant velocity in an assembly of smaller disks. On the one hand, one observes inhomogeneous shear rate and strongly localized shear stress and pressure fields. On the other hand, a significant dilation rate, which has the same magnitude as the shear strain rate, is reported. Significant deviations are observed with local rheology that justify the need of searching for a nonlocal rheology.
BibTeX:
@article{Seguin2016a,
  author = {Seguin, A. and Coulais, C. and Martinez, F. and Bertho, Y. and Gondret, P.},
  title = {Local rheological measurements in the granular flow around an intruder},
  journal = {Physical Review E},
  year = {2016},
  volume = {93},
  number = {1},
  pages = {012904},
  doi = {10.1103/PhysRevE.93.012904}
}
 

Other Publication Years:

2017, 2016, 2015, 2014, 2013, 2012, Older publications (2008-2011)

 

Maj : 07/02/2017 (2441)

 

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