HAL Université de Savoie
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Challenges in detecting volcanic forcing in climate and societal proxies: insights from the 1170/1171 CE eruption
No full textInternational audienceAbstract While our current understanding of the impacts of volcanic eruptions on the atmosphere and climate has significantly advanced, uncertainties persist regarding the climate and societal response to major volcanic events of the Common Era, especially during the high medieval period (1000–1300 CE). This study focuses on a sparsely documented medieval eruption from the late 12th century, considered, on the basis of ice-core evidence, to be one of the most prominent volcanic events of the past millennium. In this context, we explore the challenges researchers may encounter when differentiating between volcanic forcing and internal climate variability in climate and societal proxies. We highlight the importance of accurately dating volcanic eruptions for attribution studies and emphasize the need for a thorough examination of historical sources, along with a deep understanding of prevailing socio-economic and political contexts, when seeking to associate famines, pestilence, or social unrest to the climatic effects of explosive volcanism
Why is the Earth System Oscillating at a 6-Year Period?
No full textInternational audienceA 6-year cycle has long been recognized to influence the Earth’s rotation, the internal magnetic field and motions in the fluid Earth’s core. Recent observations have revealed that a 6-year cycle also affects the angular momentum of the atmosphere and several climatic parameters, including global mean sea level rise, precipitation, land hydrology, Arctic surface temperature, ocean heat content and natural climate modes. In this review, we first present observational evidences supporting the existence of a 6-year cycle in the Earth system, from its deep interior to the climate system. We then explore potential links between the Earth’s core, mantle and atmosphere that might explain the observations, and investigate various mechanisms that could drive the observed 6-year oscillation throughout the whole Earth system
Electron-electron interaction in graphene ribbons in the presence of a magnetic field
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Neck Disability Index : mesure de l’impact fonctionnel des douleurs cervicales
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Monitoring of permafrost dynamics using Electrical Resistivity tomography (ERT) at the Aiguille Du Midi in the French Alps
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A Review of Medium Voltage Power Conversion Systems for Grid-Connected Renewable Energy Sources
No full textInternational audienceA Review of Medium Voltage Power Conversion Systems for Grid-Connected Renewable Energy Source
A single exposure to prolonged flexor carpi radialis muscle vibration increases sensorimotor cortical areas activity
No full textInternational audienceProlonged local vibration (LV) is thought to promote brain plasticity, yet the underlying mechanisms remain unclear. In the present study, we used electroencephalography in healthy subjects and found increased activity in primary motor, primary somatosensory, and posterior parietal areas after a single exposure to LV. This may be due to LV-induced Ia afferents inputs projecting onto cortical areas through proprioceptive pathways, and likely triggering brain plasticity
Priority areas for nature-based adaptation to climate change in the Alps
No full textWe acknowledge EuroGeographics and JRC-EDSAC to provide licences to use products for academic purposes. We thank Bruno Locatelli for the significant insights he provided for designing the present research. We thank Lukas Egarter Vigl for the support he provided in using the AlpES project database. We thank the two anonymous reviewers the Editor in chief and the associated Editor for their valuable insights.International audienceNature-based Solutions (NbS) are promising initiatives for climate change adaptation, mitigation and biodiversity conservation. Given the finite human and financial resources for NbS, identifying optimal locations is critical. Here, we identified priority areas for adaptation to drought in the European Alps using the "bright spots" approach to estimate future water deficit and surplus from groundwater and soil moisture. We identified overlaps and mismatches of these priority areas with mitigation and biodiversity conservation opportunities. Our analyses reveal that priority areas for adaptation to drought have limited overlap with regions prioritised for mitigation or biodiversity conservation. We considered potential levers to implement NbS from local socio-ecological characteristics. Notably, over 60% of croplands and wetlands identified as priority areas for adaptation to drought overlap with protected areas. In contrast, over 52% of priority areas for adaptation to drought in forests and grasslands are located in rural regions without protection status, where participatory processes with local communities will be crucial to implement Nb
Tune and Thin Lithium Metal Anode – Toward Functional and Optimized Used with Hybrid Solid-State Halide Electrolyte
No full textInternational audienceIn the context of the energy transition, lithium metal is considered as the most promising electrode material for battery anodes due to its high capacity, low density, and thus energy density. However, the amount of lithium used in a battery must be minimized ( i.e. , the thickness of lithium metal anodes should be reduced) to increase the device energy density and to avoid its over-consumption as lithium metal is also considered as a critical raw material by the European Union. Currently, extrusion followed by lamination is the main process used to produce lithium metal foil of at least a dozen of micrometers thick. To further reduce this thickness, we have chosen to use a vacuum evaporation process (PVD), which allows for thickness control on the order of a few hundred nanometers. Lithium films ranging from 5 to 20 µm can be produced using an argon glovebox connected to a vacuum deposition chamber, thereby preventing contact with air. Through various tests, we report on the main governing deposition parameters (e.g., substrate, evaporation temperature) that significantly influence the final film microstructure, which in turn impact the Coulombic efficiency of the corresponding electrochemical cell. As an example, the Figure ( SEM pictures of lithium obtained by PVD with a) low speed deposition rate and b) high speed deposition rate ) shows SEM images of lithium film microstructures obtained with different deposition parameter speed but with similar thickness. In this work, we propose to present a study of the influence of the microstructure and thickness of thin lithium films on electrochemical performances in lithium symmetric cells using at first a solid polymer electrolyte made of poly(ethylene oxide), PEO, doped with LiTFSI salt. These performances are compared and assessed using electrochemical impedance spectroscopy, linear galvanodynamic, and lithium plating/stripping routines. In-situ imaging by X-ray tomography and SEM studies of the microstructure of post-mortem electrodeposits complete the study. Finally, to extend these observations to other materials, we compare these results with a promising hybrid solid electrolyte comprising an organic Li 3 InCl 6 phase and a polymer matrix. The effect of the solid electrolyte nature (polymer vs. hybrid) on the Coulombic efficiency permits thus to select the most promising type of thin lithium electrode for each kind of electrolyte. Figure