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Forecasting the position and timing of eruptive vents using a Particle Filter method
No full textInternational audienc
GGR Handbook of Rock and Mineral Analysis: Nano-imaging for Advanced X-ray Fluorescence and Absorption Spectroscopy Applications
No full textInternational audienceOver the last twenty years, advances in synchrotron radiation offered for the first time access to the few nanometers scale for X-ray fluorescence and absorption spectroscopies. Applications in the fields of Life Sciences, Earth & Planetary Sciences, Materials, and Environmental Sciences could delve into detailed studies of minute samples thereof at the crossroads between single atom and bulk properties. This work introduces the scope, instrumentation, and emerging applications of advanced synchrotron-based nano-X-ray fluorescence and absorption techniques, tailored for newcomers. While general concepts are covered in other chapters, this article focuses on nanoscale X-ray fluorescence imaging, a field initially developed for specific communities and now finding promising applications in Earth sciences. Although “Minerals and Rock” applications remain limited, the examples discussed here highlight significant potential, inspiring innovative and ambitious pathways. The selected examples of Nano-X-ray fluorescence and absorption applications represent just the 'tip of the iceberg, poising these spectroscopies to become essential tools for studying interactions at the atomic level, well beyond traditional geological scales. The field is rapidly advancing toward probing even smaller and more dilute samples, paving the way for future breakthroughs
Time Distributed Deep Learning Models for Purely Exogenous Forecasting: Application to Water Table Depth Predictions Using Weather Image Time Series
No full textInternational audienceDeep Learning (DL) models have revealed to be very effective in hydrology, especially in handling spatially distributed data (e.g. raster data). We have proposed two different DL models to predict the water table depth in the Grana-Maira catchment (Piedmont, IT) using only exogenous weather image time series. Both the models are made of a first Time Distributed Convolutional Neural Network (TDC) which encodes the images into hidden vectors. The first model, TDC-LSTM uses then a Sequential Module based on an LSTM layer to learn temporal relations and output the predictions. The second model, TDC-UnPWaveNet uses instead a new version of the WaveNet architecture, adapted for handling output of different length and completely shifted in the future to the input. Both models have shown remarkable results focusing on different learnable information: TDC-LSTM has focused more on bias while the TDC-UnPWaveNet more on the temporal dynamics maximizing correlation
Recent innovations to improve sustainability of batteries : a journey from materials to application
No full textInternational audienceTo face the huge demand for Li-ion batteries, it is expected to further reduce their carbon footprint and to limit the use of critical raw materials now. In this communication, we will present our recent work on battery technologies focusing on sustainability options. Our journey will cover from materials to the system, including non Li-ion battery technologies
Fabrication of Iron-Magnesite under Mild Conditions through Indirect Carbonation of Peridotite and Its Utilization as a Partial Substitute for Cement in Concrete
No full textInternational audienceThe precipitation of magnesite and dolomite from aqueous media is challenging kinetically because several hydrated or hydroxylated Mg-carbonate phases can retard or inhibit the formation of these “enigmatic” minerals under so-called mild conditions (T ≤ 90 °C and atmospheric pressure). Here, we demonstrate that Fe-magnesite can be synthesized at 60 °C in only 2 days via indirect carbonation of peridotite, following an amorphous-to-nesquehonite-to-magnesite transformation route. In this reactive configuration, the magnesite production time is significantly reduced from 2 days to only 6 h when the temperature is increased to 90 °C. The discovery of these mild conditions for magnesite production is a promising result because currently these temperatures can be reached by free-carbon energies. We also assess the incorporation of a fabricated magnesite-rich material at 90 °C as a partial cement substitute in concrete manufacturing. Preliminary results show that substituting 15 wt % of cement with magnesite-rich material could significantly reduce the CO2 footprint with minimal impact on the concrete’s mechanical-textural properties, including Young’s modulus, strength, and macro-porosity. In practice, this circular carbon approach could provide a dual advantage─reduced clinker production and permanent CO2 storage─and present a significant opportunity to lower the carbon footprint of cement production
Toward a sociological approach of emerging pollutants (microplastics, PFASs) presences in the Alps
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Is it easy to quantify Pd-107 accurately in nuclear waste?
No full textInternational audienceThe fission of uranium and plutonium results in the formation of numerous fission products. Among them, a notable radionuclide is Pd-107 with a half-life of 6.5 x 10⁶ years. It is one of the longest-lived fission products, and can be found in nuclear waste, especially in high level waste. The quantification of Pd in radioactive waste is of significant interest as it is a valuable metal that could be valorized or recycled from nuclear waste. Furthermore, waste storage facilities are required to manage the quantity of long-lived radionuclides, such as Pd-107. Moreover, the increase in decommissioning and dismantling activities in nuclear facilities, coupled with the relaunch of new nuclear power plants, will lead to a rise in the volume of waste including in Pd-107. Consequently, the accurate and sensitive quantification of Pd is a significant challenge in order to manage and recycle more effectively our nuclear waste.In the LASE laboratory at CEA in France, the characterization of radioactive waste is conducted on various matrices (sludges, concretes…) prior to their evacuation and subsequent storage in designated facilities. An innovative method for the quantification of Pd-107 in radioactive sludge and effluents has been successfully developed. It is composed of the following steps: sample digestion, resin chromatographic separations and measurements by ICP-MS Q. The results obtained from this new method were compared to those obtained from a previous in-house procedure, which required the use of harmful reagents that needed to be substituted in order to comply with REACH guidelines. The aim of this presentation to highlight the overcoming of the challenges associated with the quantification of Pd-107 in complex radioactive samples
The effects of experimental heating and alteration on melt inclusions in magmatic zircon
No full textInternational audienceMelt inclusions (MIs) in zircon can preserve information on the evolution of magmas. However, MIs in plutonic zircons are typically devitrified, consisting of multiple phases that must be remelted to obtain a homogeneous glass for reconstruction of melt composition and magma processes. We undertake a systematic investigation of melt inclusions in zircons from a ∼ 3300 Ma xenolith of tonalite gneiss from the Barberton Greenstone belt, a well-studied section of cratonic lithosphere with components dating back to 3500 Ma. To better understand the influence of experimental heating on zircon and MI chemistry, multiple aliquots of zircons were heated in an internally heated pressure vessel at 0.4 GPa and temperatures ranging from 900 to 1200 °C (Tstep = 100 °C). Homogeneous MIs in domains with low degrees of radiation damage and isolated from cracks in the zircon were found by examination of >5000 zircons by SEM (CL, BSE). Oxygen isotopes (δ18O), OH/O ratios, U-Pb isotopes, trace and rare earth element (TREE) concentrations in zircon, along with δ18O, H2O contents, and major element compositions in glassy MIs were measured by SIMS and EPMA. Investigated MIs have granitic compositions with 67 to 81 wt% SiO2. Both heated and unheated host zircon possess statistically identical and uniform δ18O values of 6.02 ± 0.45 ‰ (2SD), while OH/O ratios systematically decrease with increasing temperature of laboratory heating. Inclusion textures (BSE contrast homogeneity) and composition (H2O, δ18O) suggest that experimental heating at 1100 °C was the most successful in recovering initial MI compositions. Inclusions in lower temperature experiments either did not homogenize (900 °C) or are rarely homogenized (1000 °C), while those at higher temperature (1200 °C) are systematically dehydrated. Twenty-two hydrous MIs from the 1100 °C experiment have 3.1–11.5 wt% H2O and an average δ18O of 7.5 ± 0.9 ‰. Four zircons have a Δ18O(MI-Zrn) fractionation inconsistent with equilibration at magmatic temperatures. In general, δ18O values and TREE concentrations measured in the zircons heated at 1100 °C show consistent behavior with unannealed zircons, indicating these systems are not significantly disturbed on the μm-scale during heating experiments, and support the use of anomalous TREE concentrations/patterns as indicators of alteration. These measurements combined with Δ18O(MI-Zrn) identify the MI-zircon pairs that are unlikely to represent the melt composition at the time of entrapment. Ti-in-zircon temperatures (αSiO2 = 1, αTiO2 = 0.3) and rhyoliteMELTS thermometry of the unaltered MI-zircon pairs return similar temperature ranges of 762–833 °C and 750–865 °C respectively, and combined with the granitic major element compositions, suggest that zircons crystallized relatively late during melt fractionation and entrapped residual evolved melt. More generally, these experiments represent the first direct reconstruction of H2O contents and oxygen isotopes of Archean melts from zircon-hosted MIs, and the approach described here can be used as a model for evaluating potential alteration during experimental heating and the geologic history for MI-zircon pairs from plutonic rocks. As compared with the TREE concentrations of similar-aged detrital zircons in the Barberton terrane, the tonalite xenolith zircons are distinct and attest to the diversity of magma compositions around 3300 Ma that formed the Barberton basement. Given that no comparable rock with zircons of the same age and TREE chemistry is exposed in the Barberton terrane, this tonalite likely represents an unknown component of the Barberton basement
Parce que nos lacs le valent bien !
No full textprésentation oraleLes lacs rendent de nombreux services mais restent menacés par de multiples pressions. Cette conférence, à destination du grand public et répondant à l'invitation d'Aqualis (CISALB), a permis de mettre tout cela en lumière, avec un focus dédié au lac du Bourget
Abortion in Comparative Law: Examining Intra-Linguistic Equivalence Challenges in Current Legislative Texts across Lusophone Countries
No full textInternational audienceIn Terminology studies, equivalence is categorized as either intra-linguistic (within a single language) or inter-linguistic (between languages). This study explores intra-linguistic equivalence in legal terminology related to abortion across Portuguese-speaking countries, more particularly, in legislative texts from Brazil, Portugal, Cape Verde, Guinea-Bissau, Macao, Mozambique, São Tomé and Príncipe, and East Timor. Corpus Linguistics tools (WordSmith Tools 7.0) were used to analyze syntagmatic links between aborto (abortion), gravidez (pregnancy), and interrupção (interruption), and identify regional variations in legal concepts across Lusophone legislations, highlighting challenges for legal translators. While equivalence is often examined across languages, our findings demonstrate its relevance in analyzing intra-linguistic variations across distinct legal systems. The results indicate a lack of precise equivalence due to legislative differences in defining and regulating abortion. These disparities underscore how legal frameworks shape terminology, influencing how concepts are structured and interpreted within different jurisdictions