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Bottleneck size manipulation through the introduction of large-radius alkali ions in Na sites of a NaSICON solid electrolyte: A computational proof of concept
No full textInternational audienceNaSICON electrolytes, such as Na1+xZr2(SiO4)x(PO4)3–x (NZSP), constitute promising candidates for solid-state battery (SSB) development. Research on such fast superionic conductors has primarily focused on two key phenomena acting specifically on Na+ ion migration: (i) the Na-concentration-driven modulation effect and (ii) the incidence of substitution. While numerous experimental and computational studies have established the fundamental role of concerted migration in ionic conduction, the precise influence of bottleneck size along with its dependence on NaSICON composition remains elusive. In view of participating in this research field and following an experimentally tested strategy, suggesting that the migration bottleneck can be expanded by partially substituting diffusing Na+ ions with larger-radius alkali elements, we investigated the impact of the introduction of such point defects (i.e. K+ or Cs+ replacing Na+) on structural and Na+ diffusion aspects in the NZSP crystal structure. A proof of concept of the interest linked to this unconventional doping approach has been searched for. Theoretical investigations relying on density functional theory (DFT) and subsequent kinetic Monte Carlo simulations were involved to unravel interrelations between the ionic radius of the substituting ion and bottleneck sizes, structural changes, diffusion pathways, and ionic conductivity features. Apart from an opening of the bottleneck along the migration path as a common feature, a clear differentiation between both kinds of substituents was evidenced on various aspects, K-NZSP outperforming the undoped counterpart and effectively enabling the maximization of ionic conductivity in these envisaged NaSICON-type matrices. Furthermore, the identification─emerging from this study─of a critical bottleneck size in such systems may contribute to provide a further key clue and lead to well thought-out crystal chemical engineering of improved materials for this research area
Resources creation of Bengali for SPPAS
No full textInternational audienceThe development of HLT (Human Language Technology) tools inevitably involves the need for language resources. However, only a handful of languages possess such resources for free. This paper presents the development of such speech tools for the Bengali language. It focuses particularly on developing language resources for text normalisation, phonetization, forced-alignment and syllabification of Bengali. This aids in developing an automatic speech annotation system for predicting the pronunciation and alignment at phoneme, syllable and word levels of the speech with their corresponding orthographic text in this less-resourced language. Subsequently application of these forced-alignment tools on both read and spontaneous speech styles of Bengali is compared in order to evaluate the performance of the SPPAS software. Spontaneous speech is filled with informal activities like laughter, noises and hesitations that make identification and alignment of phonetic entities with their corresponding transcription more problematic. The UBPA (Unit Boundary Positioning Accuracy) measure of the proposed forced-alignment system is 93.95% accurate in the case of read speech and 76.53% for spontaneous speech within a delta range of 40 ms. These newly created resources of Bengali have been integrated into the SPPAS software and distributed freely under the terms of public licenses
Muon tracking in a LiquidO opaque scintillator detector
No full textInternational audienceLiquidO is an innovative radiation detector concept. The core idea is to exploit stochastic light confinement in a highly scattering medium to self-segment the detector volume. In this paper, we demonstrate event-by-event muon tracking in a LiquidO opaque scintillator detector prototype. The detector consists of a 30 mm cubic scintillator volume instrumented with 64 wavelength-shifting fibres arranged in an 88 grid with a 3.2 mm pitch and read out by silicon photomultipliers. A wax-based opaque scintillator with a scattering length of approximately 0.5 mm is used. The tracking performance of this LiquidO detector is characterised with cosmic-ray muons and the position resolution is demonstrated to be 450 m per row of fibres. These results highlight the potential of LiquidO opaque scintillator detectors to achieve fine spatial resolution, enabling precise particle tracking and imaging
Self-employment, health, and health care: When the going gets tough, the tough get going?
No full textInternational audienceThis study provides a life-course analysis of the relationship between self-employment, health, and health care use among individuals aged 50 and older in Europe. Using data from the Survey of Health, Ageing, and Retirement in Europe (SHARE), we apply first-difference and dynamic panel data models that go beyond standard approaches in mitigating endogeneity concerns. Our findings show that the self-employed enjoy better health at younger ages, consistent with a selection effect. In addition, they experience a steeper decline in physical health over time. We also document two distinct phases of health care use: during working life, the self-employed are more likely to be hospitalised, suggesting delayed care until acute needs arise; after retirement, the number of medical visits increases, consistent with a lower opportunity cost of care
Intégrer des méthodes créatives dans des pratiques de recherche auprès de personnes en situation de vulnérabilité
No full textInternational audienceThe presentation will explore the contribution of creative methods to research with vulnerable populations. The presentation will cover various methods, primarily visual, and their authors (photo elicitation; photo voice; documentary photography; critical cartography; mind maps; and sensory cartography).L'objet de la présentation est de s'interroger sur l'apport des méthodes créatives dans la recherche auprès de personnes en situation de vulnérabilité. L'exposé présente diverses méthodes essentiellement visuelles et leurs auteurs (photo élicitation; photo voice; photographie documentaire; cartographie critique; cartes mentales; cartographie sensible
CFD simulation of thermal performance enhancement of an integrated collector storage solar water heater ICSSWH
No full textInternational audienceIn this chapter, modified designs of an Integrated Collector Storage Solar Warer Heater ICSSWH are studied. Three-dimensional CFD models are so developed to predict the thermal performances of these solar systems. The proposed changes consist of using a double glass and a double storage tank based systems. Numerical simulation results show that the use of two superposed glasses allows a reduction of the night thermal losses which are the main disadvantage of the ICSSWH. Concerning the use of two storage tanks which presents higher heat exchange surface, it is shown more efficient for solar energy collection and thermal energy production
Regulation of the activity of a tetra-modular lytic polysaccharide monooxygenase from Enterobacter cloacae by inter-domain copper coordination
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Enigma portal case: exceptional urinary crystals
No full textInternational audienceQuiz focusing on the cytological analysis of urine in a case of urinary tract infection caused by E. coli, and its management with ceftriaxone treatment
Robust identification of carbon fibers & polymer matrix properties in composites from simple tensile tests
No full textInternational audienceThe behavior of constituents in carbon fibre-reinforced plastic composite is often challenging to measure. Carbon fibres typically exhibit transversely isotropic elastic behavior, yet their parameters are challenging to measure directly due to their small diameter. Likewise, matrix suppliers often provide only elastic parameters, and neat matrix samples may be unavailable or may behave differently in isolation than within the composite. To access these properties, an alternative is to identify constituent properties from tests at the macroscopic level on the composite and inverse homogenization. This work presents a methodology for unidirectional composites that combines a simple experimental protocol with an inverse identification procedure to determine the anisotropic elastic parameters of carbon fibers and the viscoelastic behavior of the matrix. Particular emphasis is placed on designing straightforward tests and making methodological choices that enhance robustness, such as representative volume element selection guided by sensitivity analysis. Two complementary validation strategies are implemented: (i) uncertainty quantification of the identified fiber parameters using a Monte Carlo procedure with noisy inputs, and (ii) experimental validation of the viscoelastic matrix model by predicting the creep response of a laminate configuration not used in the identification and comparing it with experimental data. The approach is applied to a prototype PAEK/carbon HS 194 gsm composite. The uncertainties on the reconstructed fiber parameters are found to be satisfactory given the simplicity of the input measurements. The identified matrix model accurately reproduces the response of the validation laminate