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Mass transfer evaluation of the hydration of an olivine-bearing monzo-diorite from the Mid-Continent Rift in Kansas (USA)
No full textInternational audienceWe studied a rock sample belonging to the Mid-Continent Rift in Kansas (USA) that is partially hydrated with the formation of serpentine and amphibole. At the mineral scale, the original mineral assemblage of olivine and orthopyroxene (+ plagioclase + alkali feldspar) is partially replaced by serpentine, magnetite, biotite, amphibole, with locally some apatite and quartz. The replacement tends to preserve the shape of the original olivine and orthopyroxene, supporting a pseudomorphic replacement. Scanning Electron Microscopy (SEM), Electron Probe Micro-Analyzer (EPMA) mineral compositional map, and mass balance equations were used to quantify the transfers of mass during fluid infiltration. Here, the hydration reactions involve the decrease of rock density and, under the assumption of volume preservation, require a significant loss of mass through the fluid phase. Indeed, this study demonstrates that the formation of the newly formed hydrated minerals results from similar mass transfers between parent mineral, fluid, and product minerals. This study also demonstrates that the redox conditions are similar during the formation of all of these hydrated minerals. These observations confirm the close relationship between local stress generated by hydration reactions, mass transfers, and the scale over which the system is open
Analytical solution and parametric design of bio-PCM-based passive BTMS for cylindrical lithium-ion cells under lumped model assumptions
No full textInternational audienceThe present study proposes a parametric investigation of a passive battery thermal management system (BTMS) utilizing bio-based phase change materials (bPCMs). The thermal network approach allocates to the cell and the bPCM two thermal nodes to accurately capture the surface and core temperatures of the cell as well as the two concentric layers of the bPCM. A novel analytical solution to the thermal network model is introduced for the first time in the context of cell-bPCM configuration. The resolution is implemented through the zero-order hold discretisation technique, which involves piecewise time integration. Validation against experimental and computational fluid dynamics data under variable load demonstrates the model's predictive capability. Notably, this work features an extensive parametric analysis, examining both bPCM and cell thermo-physical parameters, thereby providing new insight into their effects on thermal performance over consecutive charge-discharge cycles. Results indicate that a 6 mm bPCM layer thickness was identified as optimal, providing a balance between thermal performance and system compactness. A lower melting point within the operating range leads to earlier activation of latent thermal absorption. The heat of fusion showed diminishing benefits beyond 200 kJ/kg, while bPCM thermal conductivity mainly improved internal homogeneity rather than peak suppression. Variations in bPCM density showed negligible impact on peak cell temperature but influenced thermal storage capacity. Furthermore, the study encompasses the effects of battery format, where the cell radius was found to be inversely proportional to temperature spikes observed, while cells with higher heat capacity showed improved resilience to thermal spikes. Notably, increasing the ambient heat transfer coefficient from 5 to 100 W/m2.K significantly enhances heat dissipation to the environment and promotes thermal recovery of the bPCM between cycles, reducing peak cell temperatures by up to 3 °C. Additionally, analysis of the BTMS under realistic driving conditions (WLTC, JC08, CLTC, NEDC, UDDS) underscores the system's ability to maintain the cell operating temperature within its optimal range (<36.2 °C), with temperature differences below 6 °C across all driving scenarios examined. This work provides a scalable tool for BTMS design and sizing, facilitating the integration of sustainable solutions into electric vehicles
Situations de vulnérabilités en contexte plurilingue dans les espaces francophones
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Autonomie stratégique européenne ou souveraineté européenne ? Analyse juridique du discours politique
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Interior and boundary regularity of mixed local nonlocal problem with singular data and its applications
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Autoroute A69 : « En matière de grands projets, la justice administrative a tendance à favoriser la raison d’Etat au détriment du respect de la légalité »
No full textValidation of Synthetic Method Phase Equilibria Measurements: Re-examination of CO₂ + Methylcyclopentane, CO₂ + 2,2-Dimethylbutane, and Benchmarking with CO₂ + Toluene
No full textInternational audienceRecent publications have reported phase equilibrium data for CO₂ + methylcyclopentane (MCP) and CO 2 + 2,2dimethylbutane using static-analytical sampling methods that are inconsistent with previously published synthetic-method data. To verify the reliability of our earlier measurements, we have repeated vapor-liquid equilibrium (VLE) experiments for both CO₂ + MCP and CO₂ + 2,2-dimethylbutane in the range 20-90 • C using a high-pressure variable-volume PVT cell with visual observation. Our new data agree within 1-2 bar with the values previously reported by our group, confirming the reproducibility of the synthetic method. To further validate our methodology, we also investigated the CO₂ + toluene system, which has been extensively studied in the literature. Our experimental results are in agreement with reference data, thereby confirming the accuracy of the synthetic technique and of the procedures used for mixture preparation and bubble-point detection. These results support the conclusion that the discrepancies between our data and those obtained by static-analytical methods cannot be attributed to errors inherent to the synthetic technique.</div
Pseudopaline-mediated zinc uptake by Pseudomonas aeruginosa drives clinically relevant phenotypes and infection outcomes
No full textInternational audienceBiological metals are vital trace elements required by metalloproteins, which are involved in virtually every cellular, structural, and catalytic function of the bacterial cell. Bacterial pathogenesis involves a tug-of-war between the host's nutritional immunity sequestering essential metals and the invading pathogens that deploy adapted high-metal affinity uptake strategies, such as metallophores, in order to efficiently circumvent these defense mechanisms. Pseudopaline is a metallophore produced and secreted by Pseudomonas aeruginosa to acquire zinc when the bioavail ability of this metal is severely restricted, as in the presence of a strong metal che lator such as EDTA, or during infections when the nutritional immunity of the host is active. We show that when facing strong metal chelation, the general Znu zinc uptake pathway becomes ineffective and only the pseudopaline pathway is capable of supplying the bacteria with the necessary zinc to maintain their growth, establishing that the pseudopaline pathway is the last-resort pathway for the bacteria to acquire zinc under such restricted growth conditions. Based on this statement, the present study explores the pleiotropic role of pseudopaline-mediated zinc acquisition on clinically relevant phenotypes such as biofilm formation and associated antibiotic tolerance, as well as its capacity to determine infection outcomes using cell-culture and murine models. The expression of pseudopaline-dependent phenotypes in such a diversity of biological contexts demonstrates the essentiality of this specific metal uptake system for P. aeruginosa pathogenicity during infection. We therefore identify this machinery as a promising therapeutic target for P. aeruginosa infections