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Exergetic Dynamic Optimization of upstream oil and gas offshore assets
No full textInternational audienceThe current global climate context requires massive decarbonization of our energy production assets by significantly developing new methodologies for analyzing and transforming production sites. The aim of this paper is to present the relevant aspects of integrated dynamic exergetic modeling to identify GHG and energy efficiency optimization levers on a company’s real case of an offshore upstream site. The main approach focuses on building a Python implemented exergetic model to perform custom dynamic simulations that include both subsurface equipment’s and surface processes, capable of accommodating a wide range of implementable interfaces and optimization solvers. To achieve this, the softwares : GAP from Petex (Subsurface model) and internally developed at TotalEnergies BEST (surface model) has been coupled together. Then a comprehensive and detailed exergy balance was carried out using this model and comparing with past experimental data to validate the model. The current global climate context requires massive decarbonization of our energy production assets by significantly developing new methodologies for analyzing and transforming production sites. The aim of this paper is to present the relevant aspects of integrated dynamic exergetic modeling to identify GHG and energy efficiency optimization levers on a company’s real case of an offshore upstream site. The main approach focuses on building a Python implemented exergetic model to perform custom dynamic simulations that include both subsurface equipment’s and surface processes, capable of accommodating a wide range of implementable interfaces and optimization solvers. To achieve this, the softwares : GAP from Petex (Subsurface model) and internally developed at TotalEnergies BEST (surface model) has been coupled together. Then a comprehensive and detailed exergy balance was carried out using this model and comparing with past experimental data to validate the model
Faire lumière sur le stockage du CO2 !
No full textInternational audiencePour contraster l’augmentation de la température de notre planète, il faut mettre en place des technologies de capture, utilisation et stockage du carbone. Le CO₂ capté peut être utilisé ou stocké dans des aquifères salins profonds, où sa dissolution dans la saumure est accélérée grâce à la convection. Au LFCR, nous avons analysé ce processus en montrant que le déclenchement de la convection suit une loi universelle, ce qui permet de prédire le comportement dans un vrai réservoir
3D Electron diffraction on nanoparticles: minimal size and associated dynamical effects
No full textInternational audienceOver the past decade, advances in electron diffraction (ED) have significantly improved the determination and refinement of crystal structures, making it a viable alternative to traditional X-ray diffraction (XRD), especially for very small volumes, such as nanoparticles (NPs). This work evaluates the application of advanced 3D ED techniques to the analysis of isolated NPs, focusing on their efficacy and limitations in terms of crystal size and accuracy of results. Our investigation begins by addressing the challenges of obtaining 3D ED data for NPs, including sample preparation, instrument capabilities, and the choice of 3D ED methods. We find that 3D ED can provide highly accurate structure refinements for crystals in the 50-100 nm range and is also effective for the analysis of NPs as small as 10 nm. While kinematical approximations often provide accurate refinements similar to those obtained from powder XRD, the accuracy depends on the specific data set and may not always align with traditional reliability indicators.Our study shows that dynamical scattering effects, even in tiny crystals, challenge the assumption that they are negligible in thin crystal scenarios. Addressing these effects through full dynamical refinement significantly improves the accuracy and reliability of the structure determination. This report suggests a paradigm shift in viewing dynamic scattering effects not as mere obstacles but as opportunities to explore crystal structures in greater detail on smaller scales. By embracing these complexities, 3D ED can provide precise and reliable structural insights that are critical to the advancement of nanotechnology and materials science
L'otolithe : voyage dans l'intimité du saumon de l'Allier
No full textNational audienceIn a context marked by growing climatic and environmental pressures, it became essential to acquire new knowledge about the origin of salmon returning to spawn in the Allier basin. This required innovative methods. This is where the salmon otolith – or more precisely its chemical composition – plays a key role. A veritable biological ‘black box’, this small calcareous structure located in the inner ear records the chemical elements present in the water over time in the form of successive layers. As part of the HISALOCO project (Life history of Loire salmon as seen through the chemistry of their otoliths, 2024-2025), funded by the Loire-Bretagne Water Agency, the European Union (ERDF funds) and the CNRS, this method was used to meet three objectives: (1) to determine whether the salmon returning to spawn were born in the Allier or one of its tributaries, (2) to identify those from the Chanteuges fish farm and the rivers where they were released, and (3) to track their migratory route in the river, in particular by identifying the moment of transition from fresh water to salt water and their wandering in the Allier. 233 salmon otoliths were analysed using femtosecond laser ablation (fsLA), coupled with inductively coupled plasma mass spectrometers (ICP-MS and MC-ICP-MS), at the UPPA's PAMAL centre of expertise. Thanks to these analyses and the creation of a map of the chemical composition of the waters of the Allier basin, the otolith has just begun to reveal its secrets. Based on the zinc/calcium (Zn/Ca) ratio in the otoliths, 190 individuals belong to cohorts born between 2008 and 2015, i.e. fish that returned to spawn in the Allier between 2011 and 2019. Strontium isotopes (87Sr/86Sr) show: 1) a wild (anadromous) contribution of around 58%, with no clear trend over these eight consecutive cohorts, the Allier contributing much more significantly than the Alagnon to the return of wild salmon, suggesting that the Allier remains the main contributor to natural reproduction; 2) a contribution from restocking (Chanteuges hatchery) of approximately 42%, with returns from restocking in the Alagnon comparable to those in the Allier, despite much lower releases in the Alagnon compared to the Allier, suggesting a high yield from restocking in the Alagnon.Dans un contexte marqué par des pressions climatiques et environnementales croissantes, il devenait essentiel d’acquérir de nouvelles connaissances sur l’origine des saumons revenus se reproduire dans le bassin de l’Allier. Pour cela, des méthodes innovantes étaient nécessaires. C’est ici que l’otolithe du saumon – ou plus précisément sa composition chimique – joue un rôle clé. Véritable « boîte noire » biologique, cette petite structure calcaire située dans l’oreille interne enregistre au fil du temps, sous forme de couches successives, les éléments chimiques présents dans l’eau. Dans le cadre du projet HISALOCO (Histoire de vie du saumon de la Loire vue par la chimie de ses otolithes, 2024-2025), financé par l’Agence de l’Eau Loire-Bretagne, l’Union européenne (fonds FEDER) et le CNRS, cette méthode a été utilisée pour répondre à trois objectifs : (1) déterminer si les saumons revenus frayer sont nés dans l’Allier ou dans l’un de ses affluents, (2) identifier ceux issus de la pisciculture de Chanteuges ainsi que les rivières où ils ont été relâchés, et (3) suivre leur parcours migratoire en rivière, en identifiant notamment le moment du passage de l’eau douce à l’eau salée et leur divagation dans l’Allier. 233 otolithes de saumons ont été analysés par ablation laser femtoseconde (fsLA), couplée à des spectromètres de masse à plasma induit (ICP-MS et MC-ICP-MS), au centre d’expertise PAMAL de l’UPPA. Grâce à ces analyses et l’établissement d’une carte de la composition chimique des eaux du bassin de l’Allier, l’otolithe vient de commencer à livrer ses secrets. Sur la base du rapport zinc/calcium (Zn/Ca) dans les otolithes, 190 individus appartiennent aux cohortes nées entre 2008 et 2015, soit des poissons revenus frayer dans l’Allier entre 2011 et 2019. L’isotopie du strontium (87Sr/86Sr) montrent : 1) une contribution d’origine sauvage (anadrome) d’environ 58%, sans tendance nette sur ces 8 cohortes consécutives, l’Allier concourant de manière bien plus importante que l’Alagnon aux retours de saumons sauvages, suggérant que l’Allier reste le principal contributeur à la reproduction naturelle ; 2) une contribution d’origine repeuplement (écloserie de Chanteuges) d’environ 42%, avec des retours issus de repeuplement dans l’Alagnon comparables à ceux de l’Allier, et ce, malgré des lâchers bien moindres dans l’Alagnon par rapport à l’Allier, suggérant un rendement élevé du repeuplement dans l’Alagnon
"Un Cholœpus didactylus pour les collections du Muséum d’histoire naturelle ou Leschenault de la Tour et le aï “fatal” (Guyane française, décembre 1823-août 1824)"
No full textInternational audienceA leading naturalist figure in the early 19th century, Jean-Baptiste Leschenault de La Tour (1773–1826) gained rapid scientific recognition by participating at a young age in the Baudin expedition sent by the First Republic to the Southern Lands. After many adventures, he returned to France in 1807, bringing back impressive collections (stuffed birds, insects, butterflies, plants, animal skeletons, molluscs, fish and even two stone statues from a ruined temple on the island of Java!). While this episode is well known, thanks in particular to the work of Viviane Desmet and Pierre Jangoux, the same cannot be said of his last scientific expedition to South America. A (short) exchange of letters between the naturalist and the Natural History Museum (in Paris), which we discovered ourselves in the archives of French Guiana, sheds some light (albeit modestly) on the difficulties encountered in collecting and sending specimens of scientific interest, which in this case proved fatal for our naturalist.(tanslated with DeepL.com, free version)Jean-Baptiste Leschenault de La Tour (1773-1826), gran figura naturalista de principios del siglo XIX, alcanzó un reconocimiento científico fulgurante al participar, siendo muy joven, en la expedición Baudin enviada por la Primera República a las Tierras Australes. Tras múltiples peripecias, regresó a Francia en 1807, trayendo en su equipaje impresionantes colecciones (aves disecadas, insectos, mariposas, plantas, esqueletos de animales, moluscos, peces e incluso dos estatuas de piedra procedentes de un templo en ruinas de la isla de Java). Si bien este episodio es bien conocido, sobre todo gracias a los trabajos de Viviane Desmet y Pierre Jangoux, no ocurre lo mismo con su última expedición científica a Sudamérica. Un (breve) intercambio epistolar entre el naturalista y el Museo de Historia Natural (de París), descubierto por nosotros mismos hace tiempo en los fondos de los Archivos Departamentales de Guayana, nos ilustra (modestamente) sobre las dificultades encontradas en la recolección y el envío de especímenes de interés científico, que en este caso resultaron fatales incluso para nuestro naturalista.Grande figure naturaliste du tout début du XIXe siècle, Jean-Baptiste Leschenault de La Tour (1773-1826) acquit une reconnaissance scientifique quelque peu fulgurante en participant tout jeune à l’expédition Baudin envoyée par la Première République aux Terres Australes. Après de multiples péripéties, il retrouvait la France en 1807, ramenant dans ses bagages des collections impressionnantes (oiseaux empaillés, insectes, papillons, végétaux, squelettes d’animaux, mollusques, poissons et même deux statues en pierre originaires d’un temple en ruines de l’île de Java !). Si c’est épisode est bien connu, notamment grâce aux travaux de Viviane Desmet et Pierre Jangoux, il n’en est pas de même de sa dernière expédition scientifique en Amérique du Sud. Un (court) échange épistolaire entre le naturaliste et le Muséum d’histoire naturelle (de Paris), mis à jour par nous-même jadis dans les fonds des Archives départementales de Guyane, nous éclaire (modestement) sur les difficultés rencontrées quant à la collecte et l’envoi de spécimens d’intérêt scientifique, ici fatales même dans le cas de notre naturaliste
Discussion du dossier de la revue Politique européenne, consacré à l’étude anthropologique de l’Europe
No full textInternational audienceDiscussion du dossier de la revue Politique européenne, consacré à l’étude anthropologique de l’Europe, lors des rencontres d'automne du Gis-Eurolab à la Maison de l'Europe à Paris (21 novembre 2025). Les commentaires soulevés tentent d'interroger la pratique de recherche de la science juridique, et de manière réflexive celle de l'anthropologie, en faisant du constant de leurs apports mutuels potentiels
"Les paysages yucatèques dans l'oeuvre romanesque de Désiré Charnay (1828-1915)"
No full textInternational audienceDésiré Charnay was something of an unusual figure in French science in the second half of the 19th century: an explorer, photographer and archaeologist, he is considered in his homeland to be one of the founders of ‘Americanism’. And while his photographs of the Mayan sites in Yucatan are world-renowned, as are his scientific writings, the two geographical novels he published with a major publisher, Hachette, at the height of his fame, quickly fell into oblivion, their reprinting ceasing with the First World War. Our paper will therefore seek to answer the following key question: are Désiré Charnay's novels distinguished by a particular style and/or structure that reflects his unique status as a scientist? And more generally, do his texts give particular prominence to landscape description?Désiré Charnay es una figura algo singular de la ciencia francesa de la segunda mitad del siglo XIX: explorador, fotógrafo y arqueólogo, es considerado en su país natal como uno de los fundadores del «americanismo». Y aunque sus fotografías de los yacimientos mayas de Yucatán son mundialmente conocidas, al igual que sus escritos científicos, las dos novelas geográficas que publicó en una editorial «de peso», la casa Hachette, cuando su fama estaba en su apogeo, cayeron rápidamente en el olvido, y su reedición se interrumpió con la Primera Guerra Mundial. Por lo tanto, nuestra comunicación se centrará en responder a la siguiente gran pregunta: ¿se distinguen los escritos novelescos de Désiré Charnay por un estilo y/o una construcción particulares, reflejo de su singular condición de científico? Y, en términos más generales, ¿conceden sus textos un lugar especial a la descripción paisajística?Désiré Charnay es una figura algo singular de la ciencia francesa de la segunda mitad del siglo XIX: explorador, fotógrafo y arqueólogo, es considerado en su país natal como uno de los fundadores del «americanismo». Y aunque sus fotografías de los yacimientos mayas de Yucatán son mundialmente conocidas, al igual que sus escritos científicos, las dos novelas geográficas que publicó en una editorial «de peso», la casa Hachette, cuando su fama estaba en su apogeo, cayeron rápidamente en el olvido, y su reedición se interrumpió con la Primera Guerra Mundial. Por lo tanto, nuestra comunicación se centrará en responder a la siguiente gran pregunta: ¿se distinguen los escritos novelescos de Désiré Charnay por un estilo y/o una construcción particulares, reflejo de su singular condición de científico? Y, en términos más generales, ¿conceden sus textos un lugar especial a la descripción paisajística
Thermal assessment of Li-ion batteries incorporating phase change materials using a new 2D model
No full textInternational audienceThis paper presents a novel physical model to analyse the energy efficiency of a thermal management system based on a phase change material (PCM) for Li-ion batteries including diffusion and irreversible phenomena such as entropy. Real-world battery performance was assessed using the New European Driving Cycle (NEDC), which includes four urban routes and one ultra-urban route. The model's accuracy was validated against experimental data, and an in-depth analysis of various parameters was conducted. The results show that the choice of PCM melting temperature range is pivotal in the battery thermal management system (BTMS) performance, with RT-28HC and RT-31 exhibiting superior thermal regulation during the three charge and discharge cycles. Although the thermal gradient within the pack is often negligible under different ambient conditions, higher ambient temperatures (40 • C) or high convective coefficients (60 W/m2K) increased thermal gradients. Simulations reveal that combining PCM and active cooling systems is required to reduce thermal gradients and maintain temperature uniformity, especially in extreme conditions and long operating times. This new model provides a cost-effective, agile alternative to computationally intensive methods for analysing dynamic thermal behaviour during long charge and discharge cycles
High-Pressure Phase Equilibrium in the Carbon Dioxide + Branched Alkane Binary Systems: 1. Carbon Dioxide + 2,2-Dimethylbutane
No full textInternational audienceIsothermal vapour–liquid equilibrium (VLE) data and liquid-phase densities were experimentally determined for the first time, to the best of our knowledge, for the carbon dioxide (CO2) + 2,2-dimethylbutane (2,2-DMB) binary system. Measurements were conducted using an analytical-static method (“AnTVisVarCap” as described in the “High-Pressure Fluid-Phase Equilibria” review series by Dohrn and co-workers) with phase sampling performed via high-precision valves and analysed by gas chromatography. Liquid-phase densities were obtained by recirculating the liquid through a high-pressure vibrating-tube densimeter installed within the liquid loop. The system was investigated over a temperature range of 313.15–383.15 K and pressures spanning from 11.1 to 103.2 bar. Thermodynamic modelling of the CO2 + 2,2-DMB mixture was performed using the General Equation of State (GEOS), Peng–Robinson (PR), and Soave–Redlich–Kwong (SRK) equations of state (EoSs). These were applied in combination with classical van der Waals two-parameter conventional mixing rules (2PCMR) and Adachi–Sugie (AS) mixing rules and various excess Gibbs energy-based mixing rules, including COMB1, COMB2, HV-residual UNIQUAC (HV-RU), MHV1, and MHV2. While the applied models predicted either type I or type II phase behaviour according to the classification scheme of van Konynenburg and Scott, no experimental evidence of liquid–liquid phase separation was observed within the studied temperature and pressure range. The newly studied system was analysed in comparison with the corresponding linear alkane, n-hexane, as well as with the other branched isomer, 2,3-dimethylbutane. For the latter, experimental data are available from both our research group and an independent study
Millions of mass spectral peaks resolved and detected: Now What?
No full textInternational audienceRealization of the potential molecular information afforded by direct infusion and on-line FT-ICR analyses of complex mixtures (i.e. lipids, metabolites, environmental, petrochemical, pyrolysis oils, aerosols, emerging contaminants) relies on confident mass calibration and subsequent elemental composition assignment. However, mass spectral performance metrics (requisite speed, signal-to-noise (S/N), resolution, mass accuracy) and compositional complexity can vary widely as a function of instrument (most commonly FT- or FT-ICR MS), application, and experiment type. Combined, these factors have created a bottleneck in the overall workflow and hindered the utilization of historic data via data mining and machine learning approaches. Herein, we describe a fully automated data processing workflow based on mass difference analysis (MDA) applicable to a variety of complex matrices.Mass differences are calculated in a software package (PyC2MC) from high to low m/z by subtracting the m/z of all detected peaks from the highest m/z, and repeated until no peaks remain. The mass difference histogram is plotted as number of occurrences vs. mass difference (Dm/z), and the center and width at half height (ɣ) are determined for all differences. A subset of unambiguous mass difference histogram(s) are used to recalibrate (global) the entire mass spectrum by optimization of the mass calibration coefficients for each mass difference pair in the selected histogram so that the measured Δm/z equals thetheoretical Δm/z. After initial global recalibration, these constraints along with accurate mass are used to determine one or more confident molecular formula assignment(s) at low m/z. These assignments are connected to all other mass peaks by graph theory, utilizing a set of unambiguous mass difference distributions (edges), which enables a subsequent walking calibration and ultimately molecular formula assignment. Finally, statistical verification of molecular formula assignments is facilitated by the relationship between precision, S/N, and resolving power that defines the allowable error for molecular formula assignment based on a user defined confidence. Its application to other mass analyzers (FTMS) will be explored. Work supported by the NSF Divisions of Materials Research and Chemistry through DMR-2128556 and DMR-1644779, FSU, and the State of Florida