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AI-accelerated digital twinning for the online PDE-based control of ISBM processes with recycled PET
No full textInternational audienceTo increase the ratio of manufactured recycled poly(ethylene terephthalate) (rPET) bottle, the control of ISBM (Injection Stretch Blow Moulding) process must account for varying mechanical and thermal properties of mechanically recycled PET. Calibration and optimization of the process have been successfully realized in past works, but they use costly PDE-based models. Therefore, they are difficult to use online for applications where the process parameters need to be regularly adjusted, i.e. whenever a new batch of preforms made of recycled PET is considered. To address this, a meta-algorithm is proposed to replace the PDE-based digital twin. A gaussian process regression is trained offline using the PDE-based digital twin results in the process’s variabilities range.Using the internal pressure history of a test ISBM operation, our strategy allows us to obtain calibrated results without solving PDEs online. To show the capability of the methodology, a simplified process and its associated parametric uncertainties are enunciated. Finite element simulations of the ISBM process where the properties follow a multivariate Gaussian distribution are used to realize the Gaussian process regression. The quality of the digital twin’s predictions is assessed. Then, an illustrative example is presented, demonstrating the use of the digital twin predictions to optimize the thickness distribution of a bottle following the blowing process
GW241011 and GW241110: Exploring Binary Formation and Fundamental Physics with Asymmetric, High-spin Black Hole Coalescences
No full textInternational audienceWe report the observation of gravitational waves from two binary black hole coalescences during the fourth observing run of the LIGO–Virgo–KAGRA detector network, GW241011 and GW241110. The sources of these two signals are characterized by rapid and precisely measured primary spins, nonnegligible spin–orbit misalignment, and unequal mass ratios between their constituent black holes. These properties are characteristic of binaries in which the more massive object was itself formed from a previous binary black hole merger and suggest that the sources of GW241011 and GW241110 may have formed in dense stellar environments in which repeated mergers can take place. As the third-loudest gravitational-wave event published to date, with a median network signal-to-noise ratio of 36.0, GW241011 furthermore yields stringent constraints on the Kerr nature of black holes, the multipolar structure of gravitational-wave generation, and the existence of ultralight bosons within the mass range 10–10 eV
Stress distribution in the edentulous maxilla during immediate loading using three rehabilitation models: a finite element analysis.
No full textInternational audienc
High-pressure acid leaching of laterite ores: Effect of acid and solid content on Ni and Co yield under non-isothermal and isothermal conditions
No full textInternational audienceThe increasing demand for nickel (Ni) in electric vehicle batteries necessitates efficient extraction methods fromlaterite ores. High-Pressure Acid Leaching (HPAL) is a prominent hydrometallurgical technique known for itsrapid kinetics and high (>90 %) metal dissolution. This study examines the influence of acid-to-ore (A/O) ratios(0.25, 0.35, and 0.45) and slurry solid contents (22, 26, and 30 wt.%) on Ni yield and selectivity under both non-isothermal (100 ◦C, 1.2 bar; 150 ◦C, 4.7 bar; 200 ◦C, 18.9 bar; 265 ◦C, 50.5 bar) and isothermal (265 ◦ C)conditions.Under non-isothermal conditions, Ni leaching efficiency improved with temperature, achieving a maximumyield of 94.67 ± 0.02 wt.% at 265 ◦C, compared to 50.86 ± 0.02 wt.% at 200 ◦C, using an A/O ratio of 0.45 and26 wt.% solids over 60 min. Isothermal experiments at 265 ◦C revealed that higher A/O ratios enhanced Ni yield,reaching 94.45 ± 0.01 wt.% at 60 min with 26 wt.% solids and an A/O of 0.45. However, this increased yieldwas accompanied by higher dissolution of Fe (1.07 ± 0.12 wt.%) and Al (38.84 ± 0.07 wt.%), reducing selec-tivity to 0.73 ± 0.01. Conversely, an A/O ratio of 0.25 at 26 wt.% solids achieved a higher selectivity of 3.83 ±0.05 but with a lower Ni yield of 79.14 ± 0.03 wt.%. Lower slurry solid content further improved Ni leaching; at22 wt.% solids and an A/O of 0.45, Ni yield reached 95.87 ± 0.01 wt.% with a selectivity of 0.89 ± 0.02 at 60min.Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analyses of leached residues indicated thathigh temperatures facilitate the transformation of primary minerals like goethite and gibbsite into hematite andhydronium alunite. This transformation is more pronounced at higher A/O ratios, affecting the mineralogicalcomposition of the post-leach solid residue
Balancing Robustness and Accuracy in Rooftop PV Estimation: Benchmarking the French TSO's Approach and Physics-Based Models
No full textThe deployment of photovoltaic (PV) systems accelerates worldwide and reached a global installed capacity reaching 1,858 GW p in 2024, France accounting for 25 GW p . However, PV grid integration is hindered by limited rooftop PV observability, as transmission system operators (TSOs) lack direct measurements of small-scale systems. This study provides the first national-scale benchmarking of the French TSO's statistical method against a physics-based approach using remote-sensing PV registries and weather data. Using ground-truth measurements from rooftop PV systems across France (2020-2023), we evaluate accuracy, robustness, and operational tradeo!s of both methods. Results show comparable accuracy (aggregated errors of approximately 4%), with the TSO method demonstrating superior robustness and the physics-based approach o!ering greater adaptability. The TSO method performs better than expected under current conditions but faces challenges from evolving PV systems, as self-consumption installations now represent 60% of new capacity. Findings highlight the critical importance of accurate PV registries for grid reliability, with implications extending beyond France to other regions with rooftop PV integration challenges.</div
Les citoyens peuvent-ils participer à produire des connaissances pour réconcilier élevage et société ? Une expérimentation dans le Massif central
No full textInternational audienceParticipatory approaches involving not only farmers but also citizens in the design of desirable futures in agriculture are developing, but remain quite limited and little studied in the field of livestock farming where the crisis of confidence with society is growing. Citizens are often only consulted to identify their perception or to promote the acceptability of innovations. Our article proposes to broaden the way in which the role of citizens in the design processes of future livestock systems can be envisaged, by proposing an analytical framework to characterize the learning dynamics generated during the participation of citizens in an intermediation system in this sector. Based on the analysis of exchanges between participants during the workshop and qualitative surveys conducted a posteriori, we highlight that the participation of citizens within this system has generated (i) the recognition and exchange of different types of knowledge as well as (ii) the integration of values which led to (iii) a reframing of the issues and the formulation of new problems, and (iv) changes in perception, posture and practices, questioning the future of research on livestock farming systems.Les approches participatives incluant non seulement des agriculteurs, mais également des citoyens dans la conception de futurs désirables en agriculture se développent, mais restent assez limitées et peu étudiées dans le domaine de l’élevage où la crise de confiance avec la société est croissante. Notre article propose d’élargir la façon dont le rôle des citoyens dans les processus de conception de futurs systèmes d’élevage peut être envisagé, en proposant un cadre d’analyse permettant de caractériser les dynamiques d’apprentissages engendrées lors de la participation de citoyens au sein d’un dispositif d’intermédiation dans ce secteur. À partir de l’analyse d’un dispositif d’intermédiation dans le Massif central, nous mettons en évidence que la participation de citoyens a engendré (i) une prise en compte et un croisement de différents types de connaissances ainsi qu’(ii) une intégration des valeurs ce qui a amené à (iii) un recadrage des enjeux et à la formulation de nouvelles problématiques, et (iv) à des changements de perception, de posture et de pratiques, questionnant l’avenir de la recherche sur les systèmes d’élevage
Témoignages de recherches engagées et performatives avec le projet CARE et la chaire « Comptabilité écologique »
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La construction des marchés du vrac en France : Des stratégies d'achalandage aux enjeux écologiques
No full textThis thesis in economic sociology focuses on bulk markets in France. An ancient practice of buying and selling, bulk goods are now offered through new technical and technological devices, are part of the commercial landscape, promote sustainability in the face of waste and overpackaging (Monnot and Reniou, 2019), and echo a socio-political context that promotes sustainable consumption practices. But in practice, various socio-technical challenges still weigh on the development of these markets: lack of product information, often limited supply, lack of convenience for consumers requiring new skills, which are often difficult to acquire (planning, preparation, long shopping times, etc.). In line with the approach to market arrangements (Callon, 2013, 2017), this thesis proposes to start from the movement of redistribution and reconfiguration of market mediations observed in these markets to analyze the customer attachment strategies (Grandclément, 2008) that are currently being proposed and the way in which the issues at stake in these markets are being reinterpreted.The first line of inquiry draws in particular on work in economic sociology on packaging and “market devices” to describe the hustle and bustle necessary to conceptualize and frame the interaction between consumers on the one hand and unpackaged products on the other. By following the professionals involved in the construction, readjustment, dynamics, and maintenance of this customer attachment strategies, the thesis sheds light on the transformations that bulk goods imply in the commercial relationship and in the ways in which supply is engaged with and evaluated. The concept of “bulk packaging,” a concept created in this thesis to acknowledge and describe the retranslation of the graphic and visual functions and elements of packaging through the buying and selling infrastructure (furniture, silos, marketing and merchandising information on these artifacts), is one way of understanding these various transformations and how bulk goods are handled by the different actors (human and non-human) involved in the exchange. This first axis is linked to the second, in order to understand how these transformations integrate the ecological values and issues that bulk goods entail. By drawing on research on consumption and socially responsible production, or “concerned markets,” the thesis aims to interpret these issues as they are reflected in distribution systems, the materials used, and the innovation processes that shape them, as well as the ways in which market professionals attempt to link these issues to the development of customer attachment strategies. The use of the market arrangements approach provides both a theoretical framework for describing these issues and an empirical strategy. In this regard, the study focuses on the design of various market infrastructures (Kjellberg et al., 2019) in terms of bulk distribution systems, the practices and attachments that unfold within them, and the networks of actors and broader issues with which they are linked. Various surveys are conducted in commercial spaces (large and medium-sized stores, bulk grocery stores, etc.), professionals are followed in their work designing these systems and the customer attachment they generate, and exploratory work is carried out in marketplaces (workshops, bulk fairs). This work ultimately reveals the full complexity inherent in bulk retail layouts.Cette thèse de sociologie économique prend pour objet les marchés du vrac en France. Pratique d'achat-vente ancienne, le vrac est proposé aujourd'hui à travers de nouveaux dispositifs techniques et technologiques, s'inscrit dans le décor des espaces marchands, porte un discours sur la durabilité devant la problématique du gaspillage et du suremballage (Monnot et Reniou, 2019), et fait écho à un contexte socio-politique de promotion des pratiques de consommation appelées à être durables. Mais dans la pratique, divers épreuves sociotechniques pèsent encore sur le développement de ces marchés : manque d'informations sur les produits, offre souvent limitée, défaut de praticité pour les consommateurs appelant de nouvelles compétences, vécues souvent difficilement (planification, préparation, temps d'achat long, etc.). En s'inscrivant dans l'approche des agencements marchands (Callon, 2013,2017), cette thèse propose de partir du mouvement de redistribution et de reconfiguration des médiations marchandes observé dans ces marchés pour analyser les stratégies d'achalandage (Grandclément, 2008) qui y sont proposées aujourd'hui et la manière dont les enjeux que ces marchés portent y sont retraduits.Le premier axe de problématisation s'appuie notamment sur les travaux en sociologie économique autour de l'emballage, des « market devices » pour décrire cet achalandage nécessaire pour penser, cadrer l'interaction entre, d'une part le consommateur, et d'autre part, des produits nus, sans emballage. En suivant les professionnels prenant part à l'achalandage dans sa construction, ses réajustements, ses dynamiques et sa maintenance, la thèse éclaire ici les transformations que le vrac implique dans le lien marchand, dans les modes d'engagement et d'évaluation de l'offre. Le « vrac-emballé », concept forgé dans cette thèse, pour prendre acte et décrire la retraduction des fonctions et éléments graphiques, visuels de l'emballage à travers l'infrastructure d'achat-vente (meuble, silos, informations marketing et merchandising sur ces artefacts), est une piste pour saisir ces diverses transformations et la manière dont l'achalandage est porté par les différents acteurs (humains et non-humains) de l'échange. Ce premier axe est articulé au second, afin de comprendre comment ces transformations intègrent les valeurs et enjeux écologiques que le vrac suppose. En mobilisant les travaux autour de la consommation et de la production engagée, les « Concerned market », la thèse se propose de lire ces enjeux dans leur retraduction au travers des dispositifs de distribution, les matériaux utilisés, et à travers les processus d'innovation qui leur donnent forme, la manière dont les professionnels du marché tentent d'articuler de tels enjeux à la construction de l'achalandage.La mobilisation de l'approche des agencements marchands constitue à la fois un appareillage théorique pour décrire ces problématiques, et une stratégie empirique. Sous ce rapport, l'enquête prend pour focale la conception de diverses infrastructures de marché (Kjellberg et al., 2019) au sens des dispositifs de distribution en vrac, des pratiques et attachements qui s'y déploient, des réseaux d'acteurs et d'enjeux plus larges auxquels ils sont articulés. Ainsi, diverses enquêtes sont effectuées dans des espaces marchands (grandes et moyennes surface, épiceries vrac, etc.), des professionnels sont suivis dans leur travail de conception de ces dispositifs et de l'achalandage qu'ils traduisent, un travail d'exploration dans des places de marché (ateliers, salons du vrac) est effectué. Ce travail permet in fine de déplier toute la complexité inhérente aux agencements marchands dans le vrac
Vers une gouvernance responsable des chaines de valeur de mica : enseignements de la pratique de la formalisation de la mine artisanale par la Responsible Mica Initiative en Inde et à Madagascar
No full textThis thesis examines the formalisation of artisanal and small-scale mining as envisioned and implemented by the Responsible Mica Initiative. It shows how the initiative gradually builds forms of regulation that combine global requirements with local realities. Operating within a “grey zone,” the RMI articulates legal, economic, and political registers to build an engineering of responsibility and value-sharing rather than a top-down control mechanism. The analysis of three of its key instruments — the making of a fair price, strategies for corporate engagement, and the arrangement of responsibilities — sheds light on how the RMI reconfigures value chains into shared “chains of values.”Cette thèse porte sur la formalisation des exploitations minières artisanales et à petite échelle telle qu’elle est envisagée et mise en œuvre par la Responsible Mica Initiative. Elle montre comment l’initiative construit progressivement des formes de régulation combinant des exigences globales et des réalités locales. Tout en agissant dans une « zone grise », la RMI articule registres légaux, économiques et politiques pour construire une ingénierie de la responsabilité et du partage de la valeur, plutôt qu’un dispositif de contrôle vertical. L’analyse de trois de ses dispositifs – la fabrique d’un prix équitable, les stratégies de mobilisation des entreprises, l’agencement des responsabilités – éclaire la manière dont la RMI recompose les chaines de valeur en « chaines de valeurs » partagées