HAL Portal Univ Catholille
Not a member yet
19763 research outputs found
Sort by
La Chine, un ami qui vous veut (très moyennement) du bien
No full textInternational audienceLe Venezuela dans le contexte d'une conflictualité entre la Chine et les Etats-Uni
Critical material and regional inequality: Material demand under diverging decarbonization pathways in China’s power sector
No full textInternational audienceChina's power sector decarbonization is crucial for global climate goals. However, regional disparities in decarbonization pathways and material demands arise due to differences in resource endowment, economic development, and policy support. This study develops an integrated assessment model to evaluate critical material demand for decarbonizing China's power sector under four scenarios: Business-as-Usual (BAU), Renewable Energy (RE), Carbon Capture and Storage (CCS), and Advanced Nuclear (AN). The results show significant provincial variations, with eastern provinces favoring wind and solar, while western and coal-dependent regions rely on hydropower or CCS. Nationally, material demand peaks in the CCS scenario by 2060, especially for structural materials like copper (2250 Mt) and nickel (445 Mt). Functional materials such as silicon and indium see significant demand increases under PV-driven transitions, with silicon reaching 9300 kt and indium 14.2 Mt by 2060 in the RE scenario. These findings highlight the need for region-specific policies, long-term material supply planning, and addressing material demand imbalances for a sustainable energy transition
Urinary Dysfunction Management in Multiple Sclerosis: A Nationwide Real-Life Analysis From the French SNDS Database
No full textInternational audienceAnemia remains a major global public health concern, underscoring the need for innovative nutritional and therapeutic strategies. Indigenous food plants such as Carica papaya (pawpaw) have attracted attention as potential remedies; however, their claimed benefits require rigorous scientific confirmation through well-designed experimental models prior to clinical consideration. This study was designed to formulate and demonstrate a validated, two-stage experimental framework for the systematic assessment of plant-based anti-anemic activity, with C. papaya leaf and seed extracts used as a representative model. Anemia was experimentally induced in Wistar rats using aluminum chloride (AlCl₃) administered orally at 0.5 mg/kg daily for 14 days. The evaluation protocol consisted of two consecutive phases. In Stage 1, crude methanol extracts were screened at graded doses of 100, 300, and 500 mg/kg. Stage 2 focused on the most active extract identified in Stage 1, from which alkaloid and flavonoid fractions were isolated and tested at 75 and 150 mg/kg. Key hematological indices red blood cell count (RBC), hemoglobin concentration (Hb), packed cell volume (PCV), and full blood count were assessed throughout the 14-day treatment period. Administration of AlCl₃ produced marked anemia, evidenced by a decline in RBC from 7.15 to 5.05 × 10¹²/L and a reduction in Hb from 13.65 to 8.55 g/dL in untreated anemic controls. During Stage 1, methanol extracts of C. papaya leaves at 300 and 500 mg/kg demonstrated the strongest hematological recovery, significantly improving RBC, Hb, and PCV values toward normal ranges. In Stage 2, the leaf-derived alkaloid fraction at 150 mg/kg emerged as the most potent intervention, surpassing flavonoid fractions and exhibiting a clear dose-responsive effect. Overall, this work introduces a reliable and reproducible two-stage experimental approach for screening and characterizing plant-derived anti-anemic agents. The results highlight C. papaya leaf methanol extract, particularly its alkaloid fraction, as a promising candidate for anemia management and provide a standardized methodological framework for future studies in this area
Lithium supply chains securitization: Sovereignty, energy transition, and public contestation in the EMILI project (France)
No full textInternational audienc
Steerable Thin-Film Electrode Array for Cochlear Implantation: Design and Development for Future Atraumatic Insertion
No full textInternational audienceDuring cochlear implant surgery, standard electrode arrays are inserted into the scala tympani to stimulate the spiral ganglion cells and rehabilitate hearing in deaf patients. However, conventional electrode arrays' stiffness and passive nature lead to potential trauma or incomplete insertion during the procedure. To overcome these limitations, an original steerable thin film electrode array (TFEA) has been developed. First, the twenty gold electrodes, distributed over a 25 mm length, with an average surface area of 0.16 mm2, are significantly larger than those of existing TFEAs. These larger electrode surface areas enable safe neural stimulation within charge density limits below the Shannon threshold. By adjusting the material thicknesses, the proposed TFEA offers tunable stiffness, enabling safer and more flexible insertion. The microfabrication process, using SU-8 negative photoresist thin films, is both cost-effective and straightforward. In addition, the ability to dynamically adjust the curvature of the TFEA during insertion into a 3D printed cochlea model using low voltage conducting polymer based micro-actuator has been demonstrated. This marks the first instance of electrode array insertion with adaptive curvature, minimizing contact with cochlear walls. Successful insertion was achieved, with a curvature angle close to 360°. This active TFEA has the potential to improve insertion control and reduce the risk of trauma during cochlear implantation
Simplified finite element modeling of TBM advance: a novel computational approach
No full textInternational audienceDeveloping a numerical model of tunnel excavation using a TBM is a difficult task, due to the complexity of the phenomena involved in the advancement of the machine through the ground. The ease of use of calculation software often masks (at least in part) the representation in the numerical simulation of the actual phenomenon. Many simulations use nodal forces to account for stress relaxation at the boundary of the excavated ground and for the interaction between the TBM, the grout, and the surrounding soil. However, calibrating these models may prove difficult. This paper proposes a simple approach called "swelling method" which aims to take into account the TBM control parameters, especially the grout injection parameters. This approach allows directly defining the final stress applied to the tunnel contour, taking into account the grout pressure. The conventional and the new approaches are implemented in the finite element code CESAR and tested to simulate surface settlements and lateral soil displacements induced by tunneling using as a background a full-scale research project called TULIP (Tunneling and Limitation of Impacts on Piles). The results show strong agreement between the two methods, but the swelling method is easier to handle, and has the potential to capture the complex interactions between the TBM and surrounding soil. The influence of the model parameters on the width of the surface settlement trough are discussed
Chauvigné, C., Barthes, A., Langes, J.-M. (2026). Critical Dictionary of the Issues and Concepts in Education. Springer
No full textExperimental and DFT study of the structural, electronic, and thermoelectrical properties of Li3xLa2/3-xTiO3 (x = 0.125) ceramic leads free for battery applications
No full textInternational audienceWe synthesized Li3xLa2/3−xTiO3 (LLTO, x = 0.125) via solid-state sintering, yielding a structurally stable orthorhombic perovskite with high environmental compatibility. The resulting material was characterized experimentally through X-ray diffraction (XRD), dielectric measurements (permittivity and loss), complex impedance analysis, and electrical conductivity testing. In parallel, first-principles computations using the BoltzTraP program and Density Functional Theory (DFT) were performed to determine the structural, electronic, and thermoelectric properties. Experimental results reveal a very high dielectric constant at low frequencies and high temperatures, with moderate dielectric loss behavior typical of ion-conducting perovskites. Nyquist plots demonstrate a significant decrease in impedance with increasing temperature, indicating enhanced mobility of Li+ ions. Electrical conductivity increases with temperature, exceeding 10−2 S/m at 800 °C, and the ionic conduction activation energy is estimated to be ≈ 1.45 eV. Complementarily, DFT confirms structural stability and a 1.65 eV semiconducting band gap. BoltzTraP simulations highlight outstanding thermoelectric performance, with a Seebeck coefficient up to 4.5 µV/K at 500 K and ZT figure of merit approaching 1, increasing steadily with temperature—ideal for thermal-to-electric conversion. This work emphasizes ionic conductivity's crucial role in solid-state electrolytes: it directly impacts Li+ transport efficiency, thermal stability, and solid-state battery technologies' overall performance. Thus, LLTO's synergy of high ionic conductivity, mechanical/thermal stability, enhanced dielectric properties, and commendable thermoelectric positions it as a versatile material for next-generation solid-state Li-ion batteries and thermoelectric devices, as supported by recent research