pinecone/core-2020-05-10-deduplication huggingface dataset:
New signal processing technique for density profile reconstruction using reflectometry

International audienceReflectometry profile measurement requires an accurate determination of the plasma reflected signal. Along with a good resolution and a high signal to noise ratio of the phase measurement, adequate data analysis is required. A new data processing based on time-frequency tomographic representation is used. It provides a clearer separation between multiple components and improves isolation of the relevant signals. In this paper, this data processing technique is applied to two sets of signals coming from two different reflectometer devices used on the Tore Supra tokamak. For the standard density profile reflectometry, it improves the initialization process and its reliability, providing a more accurate profile determination in the far scrape-off layer with density measurements as low as 1016 m-1. For a second reflectometer, which provides measurements in front of a lower hybrid launcher, this method improves the separation of the relevant plasma signal from multi-reflection processes due to the proximity of the plasma
Amphiphilic copolymers based on polyoxazoline and grape seed vegetable oil derivatives: Self-assemblies and dynamic light scattering

International audienceThe behavior in solution of original structures of amphiphilic partially natural copolymers based on polyoxazoline (POx) (poly(2-methyl-2-oxazoline)) and grape seed vegetable oil derivatives (linear, T- and trident-structure) are investigated. The results show that such systems are found, using dynamic light scattering (DLS), to spontaneously self-organize into monomodal, narrow-size and stable nanoparticles in aqueous medium. The obtained hydrodynamic diameters (Dh) range from 8.6 up to 32.5 nm. Specifically, such size increases strongly with increasing natural block (i.e. lipophilic species) length due to higher hydrophobic interactions (from 10.1 nm for C19 to 19.2 nm for C57). Furthermore, increasing the polyoxazoline (i.e. hydrophilic block) length leads to a moderate linear increase of the Dh-values. Therefore, the first order size effect comes from the natural lipophilic block whereas the characteristic size can be tuned more finely (i.e. in a second order) by choosing appropriately the polyoxazoline length. The DLS results in terms of characteristic size are corroborated using nanoparticle tracking analysis (NTA), and also by atomic force microscopy (AFM) and transmission electron microscopy (TEM) imaging where well-defined, spherical and individual nanoparticles exhibit a very good mechanical resistance upon drying. Moreover, changing the lipophilic block architecture from linear to T-shape and keeping the same molar mass generates a branching and thus a shrinking by a factor of 2 of the nanoparticle volume, as shown by DLS. In this paper, we clearly show that the self-assemblies of amphiphilic block copolymer obtained from grape seed vegetable oil derivatives (sustainable renewable resources) as well as their tunability are of great interest for biomass valorization at the nanoscale level
Turbulence modeling of the Von Karman flow: viscous and inertial stirrings

International audienceThe present work considers the turbulent Von Karman flow generated by two counter-rotating smooth flat (viscous stirring) or bladed (inertial stirring) disks. Numerical predictions based on one-point statistical modeling using a low Reynolds number second-order full stress transport closure (RSM model) are compared to velocity measurements performed at CEA (Commissariat à l'Energie Atomique, France). The main and significant novelty of this paper is the use of a drag force in the momentum equations to reproduce the effects of inertial stirring instead of modelling the blades themselves. The influences of the rotational Reynolds number, the aspect ratio of the cavity, the rotating disk speed ratio and of the presence or not of impellers are investigated to get a precise knowledge of both the dynamics and the turbulence properties in the Von Karman configuration. In particular, we highlighted the transition between the merged and separated boundary layer regimes and the one between the Batchelor (1951) and the Stewartson (1953) flow structures in the smooth disk case. We determined also the transition between the one cell and the two cell regimes for both viscous and inertial stirrings
Impact of different convective cloud schemes on the simulation of the tropical seasonal cycle in a coupled ocean-atmosphere model.

International audienceThe simulation of the mean seasonal cycle of sea surface temperature (SST) remains a challenge for coupled ocean-atmosphere general circulation models (OAGCMs). Here we investigate how the numerical representation of clouds and convection affects the simulation of the seasonal variations of tropical SST. For this purpose, we compare simulations performed with two versions of the same OAGCM differing only by their convection and cloud schemes. Most of the atmospheric temperature and precipitation differences between the two simulations reflect differences found in atmosphere-alone simulations. They affect the ocean interior down to 1,000 m. Substantial differences are found between the two coupled simulations in the seasonal march of the Intertropical Convergence Zone in the eastern part of the Pacific and Atlantic basins, where the equatorial upwelling develops. The results confirm that the distribution of atmospheric convection between ocean and land during the American and African boreal summer monsoons plays a key role in maintaining a cross equatorial flow and a strong windstress along the equator, and thereby the equatorial upwelling. Feedbacks between convection, large-scale circulation, SST and clouds are highlighted from the differences between the two simulations. In one case, these feedbacks maintain the ITCZ in a quite realistic position, whereas in the other case the ITCZ is located too far south close to the equator
Effects of in vitro shocks and hydrothermal degradation on wear of ceramic hip joints: Towards better experimental simulation of in vivo ageing

International audienceIn an ageing world population, increasing the lifetime of orthopedic devices is of vital importance for reducing surgical risks for patients and reducing medical costs. Ceramic materials are gaining interest because of their hardness and chemical inertia with respect to metal prosthesis. Wear of the prosthetic couple (femoral head and cup) is one of the main rationales for using ceramic hip implants, because they induce much lower wear debris. The present study investigates the combined effects of shocks due to microseparation and hydrothermal ageing on the wear of Zirconia Toughened Alumina (ZTA) bearings, which have been under strong development these past ten years. Wear stripe patterns are formed on femoral heads tested on a shock device. 3D profilometry is used to evaluate the volume of worn material released from the head that averages at 0.46mm 3 /year during simulation mimicking about 15 years of ageing. This volume is larger than formerly estimated with hip walking simulators with microseparation, an effect that we tentatively attribute to a larger force (9000 N) applied here than on hip simulators where the force was not specified. The present experiment should allow refining the effect of force on the wear of ceramic femoral head, hence to simulate different patient conditions (weight, activity, accidents,...). Micro Raman spectroscopy reveals significant zirconia phase transformation within wear stripes. ZTA components show minor phase transformation during hydrothermal degradation in an autoclave when compared to changes induced by shocks. Finally, five clinically retrieved bearings are characterized for in vivo comparison, and also reveal phase transformation within wear track areas. The association of phase transformation enhancement with wear areas on in vivo samples indicates that wear is induced by shocks, rather than by hydrothermal ageing. Shock simulations are therefore essential for in vitro experimentation aiming at reproducing wear of ceramic implants and in vivo environment. On a material's point of view, it is shown that the ZTA ceramics can exhibit a beneficial phase transformation under stress, which may limit wear stripes, without suffering from significant ageing
ARE ULTRA-FAINT GALAXIES AT z = 6–8 RESPONSIBLE FOR COSMIC REIONIZATION? COMBINED CONSTRAINTS FROM THE HUBBLE FRONTIER FIELDS CLUSTERS AND PARALLELS

International audienceWe use deep Hubble Space Telescope imaging of the Frontier Fields to accurately measure the galaxy rest-frame ultraviolet luminosity function (UV LF) in the redshift range z ∼ 6–8. We combine observations in three lensing clusters, A2744, MACS 0416, and MACS 0717, and their associated parallelfields to select high-redshift dropout candidates. We use the latest lensing models to estimate the flux magnification and the effective survey volume in combination with completeness simulations performed in the source plane. We report the detection of 227 galaxy candidates at z = 6–7 and 25 candidates at z ∼ 8. While the total survey area is about 4 arcmin 2 in each parallel field, it drops to about 0.6–1 arcmin 2 in the cluster core fields because of the strong lensing. We compute the UV LF at z ∼ 7 using the combined galaxy sample and perform Monte Carlo simulations to determine the best-fit Schechter parameters. We are able to reliably constrain the LF down to an absolute magnitude of M UV = −15.25, which corresponds to 0.005 L å. More importantly, we find that the faint-end slope remains steep down to this magnitude limit with 2.04. 0.17 0.13 a =-+ We find a characteristic magnitude of M 20.89 0.72 0.60  =-+ and log (f å) = 3.54. 0.45 0.48-+ Our results confirm the most recent results in deep blank fields but extend the LF measurements more than two magnitudes deeper. The UV LF at z ∼ 8 is not very well constrained below M UV = −18 owing to the small number statistics and incompleteness uncertainties. To assess the contribution of galaxies to cosmic reionization, we derive the UV luminosity density at z ∼ 7 by integrating the UV LF down to an observational limit of M UV = −15. We show that our determination of log(ρ UV) = 26.2 ± 0.13 (erg s −1 Hz −1 Mpc −3) can be sufficient to maintain reionization with an escape fraction of ionizing radiation of f esc = 10%–15%. Future Hubble Frontier Fields observations will certainly improve the constraints on the UV LF at the epoch of reionization, paving the way to more ambitious programs using cosmic telescopes with the next generation of large aperture telescopes such as the James Webb Space Telescope and the European Extremely Large Telescope
Effect of mixed-phase cloud on the chemical budget of trace gases: A modeling approach

International audienceA multiphase cloud chemistry model coupling a detailed chemical reactivity mechanism in gas phase and aqueous phase to a cloud parcel model with a two-moment microphysical scheme has been extended to include ice phase processes. This newly developed model is used to study the influence of the ice phase on HCOOH, HNO3, H2O2 and CH2O in a mixed-phase cloud. Microphysical processes are describing the interactions between the water vapor phase, the liquid phase (cloud and rain water) and the ice phase (pristine ice, snow and graupel) in the cloud and for soluble chemical species, their transfer by mixed-phase microphysical processes has been included. In addition to microphysical transfer between iced hydrometeors, the probable two main processes incorporating soluble chemical species in iced hydrometeors are the retention in ice phase as riming or freezing occurs and the burial in the ice crystal as the crystal grows by vapor diffusion. The model is applied to a cloud event describing a moderate precipitating mixed-phase cloud forming in a continental air mass in winter. The main features of the cloud are described and the evolution of key chemical species as function of time and temperature is discussed. Sensitivity tests are performed: a run without ice to highlight the influence of ice phase on the chemical gas phase composition of the cloud, a run without burial showing that it is a negligible process, a run assuming full retention in ice for all species and a run varying the ice crystal shapes. A detailed analysis of the microphysical rates and chemical rates linked to retention and burial effects show that for this cloud event, the effect of the ice phase on gas phase composition is driven by riming of cloud droplets onto graupels, which leads to retention or not of soluble chemical species in the ice phase. Finally, the impact of crystal geometry on the efficiency of collection is studied together with its impact on the riming of cloud droplets on graupels and also on the retention of chemical species in ice phase
Passive temperature tomography experiments to characterize transmissivity and connectivity of preferential flow paths in fractured media

International audienceThe detection of preferential flow paths and the characterization of their hydraulic properties are major challenges in fractured rock hydrology. In this study, we propose to use temperature as a passive tracer to characterize fracture connectivity and hydraulic properties. In particular, we propose a new temperature tomography field method in which borehole temperature profiles are measured under different pumping conditions by changing successively the pumping and observation boreholes. To interpret these temperature- depth profiles, we propose a three step inversion-based framework. We consider first an inverse model that allows for automatic permeable fracture detection from borehole temperature profiles under pumping conditions. Then we apply a borehole-scale flow and temperature model to produce flowmeter profiles by inversion of temperature profiles. This second step uses inversion to characterize the relationship between temperature variations with depth and borehole flow velocities (Klepikova et al., 2011). The third inverse step, which exploits cross-borehole flowmeter tests, is aimed at inferring inter-borehole fracture connectivity and transmissivities. This multi-step inverse framework provides a means of including temperature profiles to image fracture hydraulic properties and connectivity. We test the proposed approach with field data obtained from the Ploemeur (N.W. France) fractured rock aquifer, where the full temperature tomography experiment was carried out between three 100 m depth boreholes 10 m apart. We identified several transmissive fractures and their connectivity which correspond to known fractures and corroborate well with independent information, including available borehole flowmeter tests and geophysical data. Hence, although indirect, temperature tomography appears to be a promising approach for characterizing connectivity patterns and transmissivities of the main flow paths in fractured rock
High-resolution microwave frequency dissemination on an 86-km urban optical link

International audienceWe report the first demonstration of a long-distance ultra stable frequency dissemination in the microwave range. A 9.15 GHz signal is transferred through a 86-km urban optical link with a fractional frequency instability of 1.3x10-15 at 1 s integration time and below 10-18 at one day. The optical link phase noise compensation is performed with a round-trip method. To achieve such a result we implement light polarisation scrambling and dispersion compensation. This link outperforms all the previous radiofrequency links and compares well with recently demonstrated full optical links
Triassic 40Ar/39Ar ages from the Sakaigawa unit, Kii Peninsula, Japan: implications for possible merger of the Central Asian Orogenic Belt with large-scale tectonic systems of the East Asian margin

International audienceThe 218.4 ± 0.4, 228.8 ± 0.9 and 231.9 ± 0.7 Ma 40Ar/39Ar laser probe pseudo-plateau ages (2σ; 49–63% 39Ar-release) of very low-grade meta-pelitic whole-rocks from the Sakaigawa unit date high-P/T metamorphism. We argue that this event occurred in a subduction–accretion complex, not along the East Asian continental margin, but on the Pacific side of the proto-Japan superterrane. Proto-Japan was a Permian magmatic arc, presently dispersed in the Japanese islands, which also contained older subduction–accretion complexes. The arc system was fringing but not yet part of the Eurasian continent. The Middle to Late Triassic high-P/T tectono-metamorphic event was partly coeval with proto-Japan's collision with proto-Eurasia along the southward extension of the Central Asian Orogenic Belt, causing the main metamorphism in the Hida-Oki terrane. It is possible that this system continued via the Cathaysia block (China) to Indochina. The Late Permian to Middle Triassic Indosinian event might stem from docking of Pacific-derived terranes with Southeast Asia's continental margin. The concept of the proto-Japan superterrane implies that the Qinling-Dabie-Sulu suture zone joined the Central Asian Orogenic Belt to the east of the North China craton and did not continue to Japan, as commonly assumed
Saturating directed spaces

8 pagesInternational audienceDirected topology is a refinement of standard topology, where spaces may have non-reversible paths. It has been put forward as a candidate approach to the analysis of concurrent processes. Recently, a wealth of different frameworks for, i.e., categories of, directed spaces have been proposed. In the present work, starting from Grandis's notion of directed space, we propose an additional condition of saturation for distinguished sets of paths and show how it allows to rule out exotic examples without any serious collateral damage. Our saturation condition is local in a natural sense, and is satisfied by the directed interval (and the directed circle). Furthermore we show in which sense it is the strongest condition fulfilling these two basic requirements. Our saturation condition selects a full, reflective subcategory of Grandis's category of d-spaces, which is closed under arbitrary limits of d-spaces, has arbitrary colimits (obtained by saturating the corresponding colimits of d-spaces), and has nice cylinder and cocylinder constructions. Finally, the forgetful functor to plain topological spaces has both a right and a left adjoint
The polarization of global container flows by interoceanic canals: geographic coverage and network vulnerability

International Colloquium organized by the The Royal Academy for Overseas Sciences (Kaowarsom). Conference programme available at: http://www.kaowarsom.be/documents/programma_interoceanic_canals_03-2012.pdfInternational audienceIt is widely acknowledged that the two major interoceanic canals of Suez and Panama play a central role in global shipping flows. However, this role has rarely been measured with precision both in terms of the geographic coverage and network topological properties of canal-dependent flows. Based on vessel movement data for containerships, this research clarifies the weight and share of canal-dependent flows globally and at the level of world regions, routes, and ports. It also estimates and maps the effects of removing canal-dependent flows from the network by means of graph-theoretical methods. While main results converge in showing a decreasing importance of canal shipping in the context of growing south-south trade exchanges, certain areas remain more dependent than others, such as Asia, Europe, and North America. The research also underlines factors of port vulnerability across the globe in relation with the two canals
Guaranteed minimum income and unemployment duration in France

International audienceIn this article, we use data from the European Community Household Panel to evaluate the impact of a French guaranteed income program, the RMI, on the hazard out of unemployment. Self-selection into the program is corrected using a multivariate duration model developed by [Abbring, J.H., van den Berg, G.J., 2003. The non-parametric identification of treatment effects in duration models. Econometrica 71 (5), 1491- 1517]. We find that RMI receipt has a strong negative impact during the first months of program participation, but that this disincentive effect quickly falls to insignificant levels after six months. Household structure also appears to be an important determinant of the importance of the adverse effect of program participation
Out-of-hospital births and the supply of maternity units in France.

International audienceMaternity unit closures in France have increased distances that women travel to deliver in hospital. We studied how the supply of maternity units influences the rate of out-of-hospital births using birth certificate data. In 2005-6, 4.3 per 1000 births were out-of-hospital. Rates were more than double for women living 30km or more from their nearest unit and were even higher for women of high parity. These associations persisted in multilevel analyses adjusting for other maternal characteristics. Long distances to maternity units should be a concern to health planners because of the maternal and infant health risks
Calibration of anisotropic yield criterion with conventional tests or biaxial test

International audienceBron and Besson yield criterion has been used to model the plastic anisotropic behavior of an aluminum alloy series 5000. The parameters of this anisotropic yield model have been identified by two different methods: a classical one, considering several homogeneous conventional experiments and an exploratory one, with only one biaxial test. On one hand, the parameter identification with conventional experiments has been carried out with uniaxial tensile and simple shear tests in different orientations to the rolling direction and with a hydraulic bulge test, all of them considered at three equivalent plastic strain levels. On the other hand, Bron and Besson yield function has also been calibrated with inverse analysis from only a cross biaxial tensile test, since it was shown that the strain distribution in the center of the cruciform specimen is significantly dependent on the yield criterion. The principal strains along a specified path in the gauge area of the cruciform specimen have been analyzed and the gap between experimental and numerical values was minimized. Finally the yield contours obtained with the two methods have been compared and discussed
Geochemistry of CI chondrites: Major and trace elements, and Cu and Zn Isotopes

International audienceIn order to check the heterogeneity of the CI chondrites and determine the average composition of this group of meteorites, we analyzed a series of six large chips (weighing between 0.6 and 1.2 g) of Orgueil prepared from five different stones. In addition, one sample from each of Ivuna and Alais was analyzed. Although the sizes of the chips used in this study were "large", our results show evidence for minor chemical heterogeneity in Orgueil, particularly for alkali elements and U. After removal of one outlier sample, the spread of the results is considerably reduced. For most of the 46 elements analyzed in this study, the average composition calculated for Orgueil is in very good agreement with previous CI estimates. This average, obtained with a "large" mass of samples, is analytically homogeneous and is suitable for normalization purposes. Finally, the Cu and Zn isotopic ratios are homogeneously distributed within the CI parent body with a spread of less than 100 ppm per atomic mass unit (amu)
AC magnetic field measurements onboard Cross-Scale: scientific objectives and instrument design

International audienceThe ACB search-coil magnetometer for Cross-Scale will measure three components of the AC magnetic field up to 4 kHz, and one component up to 100 kHz. Turbulent and coherent magnetic field fluctuations in that frequency range play an important role in the acceleration, scattering, and thermalisation of particles. ACB will, together with the other instruments of the Cross-Scale wave consortium, allow to address the key science objectives associated with plasma waves. Here, we list some of the important issues, based on the experience drawn from Cluster, and describe the instrument