126 research outputs found

    Automatic System For Carpooling Proof Computation And Delivery

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    This document aims at providing a solution to edit a carpooling proof. The proposed solution aims at providing a fully integrated solution avoiding at maximum any manual action and the use of GPS interface which is power consuming and may not be accurate enough in case of low battery or non-synchronization with satellites

    Experimental evidence concerning the significant information depth of X-ray diffraction (XRD) in the Bragg-Brentano configuration

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    X-ray diffraction in the Bragg-Brentano configuration (“XRD”) is a very established method. However, experimental evidence concerning its significant information depth, i.e. microstructure components from which maximum depth can affect the information evaluated from the acquired diffraction pattern, are scarce in the scientific literature. This depth is relevant to all XRD measurements performed on compact samples, especially layered composites and samples showing a crystallographic texture evolution. This article provides experimentally determined upper and lower limits to the significant information depth: XRD patterns acquired froma compact crystal layer through a layer of compact, amorphous glass indicate that the significant information depth of XRD using Cu Kα1 and Kα2 radiation is very likely larger than 48 μm, but smaller than 118 μm, in a material of the composition Mg2Al4Si5O18 with a density of ca. ∼2.6 g/cm3. The depth of 48 μm correlates to the depth larger than the layer of material from which 90% of the reflected X-rays originate at 2Θ = 25.8°

    A finite element/quaternion/asymptotic numerical method for the 3D simulation of flexible cables

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    A flexible cable is modeled by a geometrically exact beam model with 3D rotations described using quaternion parameters. The boundary value problem is then discretized by the finite element method. The use of an asymptotic numerical method to solve the problem, quadratic equations, is well suited to the quaternion parametrization. This combination of methods leads to a fast, robust and accurate algorithm very well-adapted for the simulation of the assembly process of cables. This is proved by running many examples involving complicated solutions

    A finite element/quaternion/asymptotic numerical method for the 3D simulation of flexible cables

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    A flexible cable is modeled by a geometrically exact beam model with 3D rotations described using quaternion parameters. The boundary value problem is then discretized by the finite element method. The use of an asymptotic numerical method to solve the problem, quadratic equations, is well suited to the quaternion parametrization. This combination of methods leads to a fast, robust and accurate algorithm very well-adapted for the simulation of the assembly process of cables. This is proved by running many examples involving complicated solutions

    Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

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    Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

    A computationally-guided non-equilibrium synthesis approach to materials discovery in the SrO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> phase field

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    Glass-crystallisation synthesis is coupled to probe structure prediction for the guided discovery of new metastable oxides in the SrO-Al2O3-SiO2 phase field, yielding a new ternary ribbon-silicate, Sr2Si3O8. In principle, this methodology can be applied to a wide range of oxide chemistries by selecting an appropriate non-equilibrium synthesis route

    Highly Nonstoichiometric YAG Ceramics with Modified Luminescence Properties

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    Y3Al5O12 (YAG) is a widely used phosphor host. Its optical properties are controlled by chemical substitution at its YO8 or AlO6/AlO4 sublattices, with emission wavelengths defined by rare-earth and transition-metal dopants that have been explored extensively. Nonstoichiometric compositions Y3+xAl5-xO12 (x ≠ 0) may offer a route to new emission wavelengths by distributing dopants over two or more sublattices simultaneously, producing new local coordination environments for the activator ions. However, YAG typically behaves as a line phase, and such compositions are therefore challenging to synthesize. Here, a series of highly nonstoichiometric Y3+xAl5-xO12 with 0 ≤ x ≤ 0.40 is reported, corresponding to ≤20% of the AlO6 sublattice substituted by Y3+, synthesized by advanced melt-quenching techniques. This impacts the up-conversion luminescence of Yb3+/Er3+-doped systems, whose yellow-green emission differs from the red-orange emission of their stoichiometric counterparts. In contrast, the YAG:Ce3+ system has a different structural response to nonstoichiometry and its down-conversion emission is only weakly affected. Analogous highly nonstoichiometric systems should be obtainable for a range of garnet materials, demonstrated here by the synthesis of Gd3.2Al4.8O12 and Gd3.2Ga4.8O12. This opens pathways to property tuning by control of host stoichiometry, and the prospect of improved performance or new applications for garnet-type materials.Financial support was provided by the ANR-18-CE08-0012 PERSIST and ANR-20-CE08-0007 CAPRE projects of the French National Research Agency (ANR) and the CNRS, the I+D+I Grants PID2021-122328OB-100 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. PhD studentships for WC and XF were financed by the Chinese Scholarship Council (project numbers 201808450100 and 202008450026). Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. EXAFS beamtime was provided by the SOLEIL synchrotron (Gif-sur-Yvette, France) under project 99210047. The project benefitted from the microscopy facilities of the Platform MACLE-CVL which was co-funded by the European Union and Centre-Val de Loire Region (FEDER).Peer reviewe

    The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

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    Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems
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