Portail des publications scientifiques IMT Mines Alès
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Intrinsic controls on the kinetics of calcium extraction from crystalline slags: Implications on CO2 mineralization
No full textInternational audienceSlags are a potent source of Ca2+ cations for CO2 mineralization reactions. Although studies have been performed to characterize the effects of processing conditions on slag dissolution rates, systematic analyses of the mineralogical controls that affect multicomponent dissolution kinetics and associated Ca release remain sparse. Here, the aqueous Ca extractability of six different types of crystalline slags: electric arc furnace (EAF), basic oxygen furnace (BOF), air-cooled blast furnace (ac-BF), co-mingled electric arc furnace (cm-EAF), stainless steel (SS), and ladle slag (LS), was quantified for varying particle size, solid-to-liquid ratio, reagent, temperature, and pH conditions. We show that the evolution of dissolved Ca over time can be described by power relationships, indicating temporally decreasing rates of Ca release, wherein the (apparent) rate constants describe extrinsic controls on kinetics. In addition, we clarified that Ca release kinetics in crystalline slags is directly related to its mineralogy, particularly the amounts of Ca-containing silicate, aluminate, carbonate, and oxide minerals, which further have distinct pH-dependent reactivities. The degree of polymerization of Ca silicates, which can be correlated with the slag’s bulk chemical composition, exerts significant control over Ca extraction rates. The outcomes of this study can be applied to optimize, for instance, mineralization carbonation processes involving the use of crystalline Ca-rich alkaline solids in various leaching environments
Characterization of volatile and semi-volatile organic compounds in the air of sports facilities
No full textInternational audienceIndoor air quality (IAQ) in sports facilities is not yet well known compared to other indoor environments such as homes, schools or offices. However, the intense activity associated with sport and the widespread use of plasticbased furniture and coverings can lead to an increase in exposure to organic contaminants. The aim of this study was to characterize the indoor air quality of 10 sports halls of different activities. Targeted and non-targeted analytical approaches were applied to provide the broadest possible screening with a focus on emerging pollutants and led to identify and quantify more than a hundred volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs). Two sampling campaigns were carried out in unoccupied and occupied rooms to assess the impact of physical activities on IAQ. For VOCs, composition and concentration levels are globally close to those of other indoor environments, with a predominance of carbonyls, especially hexanal. However, some specific and emerging compounds (like benzothiazole, decamethylcyclopentasiloxane and 1-(2methoxy-1-methyl ethoxy)-2-propanol)) were highlighted. Acetone and 6-methyl-5-hepten-2-one, emitted by human body, were identified as occupancy tracers. For SVOCs, phthalates (DiBP, DBP) are the most abundant in compositions, followed by organophosphate flame retardants (EHDPP, TCPP) and PAHs (fluorene, phenanthrene) with particularly high PAH concentrations in one weight room, probably released from a recycled rubber flooring. The impact of ventilation on VOC and SVOC concentrations in air was also assessed, with an overall positive effect
Tensor Decompositions for Signal Processing: Theory, Advances, and Applications
No full textInternational audienceIn the era of big data, rapid advancements in technology and data collection methods have led to the generation and accessibility of vast amounts of multi-modal, high-dimensional data across a diverse range of disciplines. Tensor methods have emerged as essential tools in signal processing, providing powerful frameworks to model and analyze such complex data effectively. This survey offers a comprehensive overview of tensor factorization techniques and their applications in key areas. We explore their role in remote sensing, focusing on tensor-based methods for analyzing hyperspectral and multispectral images, tackling challenges such as recovering super-resolution images and addressing spectral unmixing. In wireless communication, we examine tensor methods used for signal modulation in unsourced massive random access communication, which achieve strong performance in multi-antenna channel and signal modeling. We also discuss tensor applications in network compression, where they reduce the computational demands of deep neural networks, making them more feasible for edge devices. Additionally, we highlight the use of tensor methods in high-dimensional missing data completion problems, showcasing their versatility across various domains. Furthermore, we explore applications in image analysis and computer vision, where tensors are effectively utilized for motion and object tracking, 3D modeling, analysis of satellite imaging, and medical imaging. By bridging theoretical advancements with practical applications, this survey aims to guide researchers in leveraging tensor methods to tackle emerging challenges in signal processing
Terres de trésors : le renouveau des collections géologiques d’IMT Mines Alès (Gard)
No full textInternational audienceL’École pratique des Maîtres-Ouvriers-Mineurs d’Alès a été établie par une ordonnance royalele 22 septembre 1843, et a rapidement développé une collection significative d’environ mille échan-tillons de minéraux, de roches et de fossiles. À partir de 1861, les excursions géologiques desélèves et l’envoi d’anciens étudiants dans les colonies ont considérablement enrichi ces collections.En 1936, la famille de Billy, un ancien ingénieur des mines de Paris, a fait des dons importantsen minéralogie et paléontologie, augmentant encore la valeur de ce patrimoine scientifique.Le décret du 18 août 1966 a transformé l’établissement en une école d’ingénieurs spécialiséedans les travaux miniers, tout en poursuivant l’enseignement de la géologie grâce à des travauxpratiques effectués sur le terrain et en salle de classe. Cependant, à partir des années 1990,l’importance accordée à la géologie a commencé à diminuer. En 1991, la salle des collectionsa été inaugurée comme le musée minéralogique de l’école, nommé " Salle Paul et Marie Fitte", suite à une donation de la famille Fitte. Malheureusement, ce musée a fermé ses portes en 2017.Aujourd’hui, la collection est répertoriée dans l’inventaire national du patrimoine géologiquesous le numéro OCC0049. Elle compte environ 12 000 minéraux, 2 000 fossiles et 600 roches.Près de 300 échantillons sont exposés dans différents bâtiments d’IMT Mines Alès, rappelantaux étudiants l’héritage géologique de l’école. Le reste de la collection est conservé dans desréserves, y compris une salle d’archives abritant 1 500 minéraux en vitrine, tandis que plus de10 000 échantillons sont soigneusement conditionnés et répertoriés.De nombreuses actions sont entreprises tout au long de l’année pour sensibiliser les scolaires etle grand public à la valeur des collections, en abordant des problématiques modernes telles quele changement climatique et les ressources minérales. L’événement annuel Minér’Alès proposedivers ateliers, excursions, expositions et conférences pour explorer ces enjeux. La revalorisationdes collections minéralogiques, pétrographiques et paléontologiques est aujourd’hui une prioriténationale, favorisant ainsi la diffusion des savoirs sur notre patrimoine naturel et les défis del’exploitation raisonnée des ressources
Proceedings of the 5th Conference on Language, Data, and Knowledge
No full textAccéder au document : http://www.fedoabooks.unina.it/index.php/fedoapress/catalog/view/681/768/3456International audienceQuesto volume contiene gli atti della quinta conferenza Language Data and Knowledge (LDK), che si è tenuta a Napoli, Italia, dal 9 all’11 settembre 2025. L’evento si è svolto in modalità ibrida, con la maggior parte dei partecipanti presenti in loco. La conferenza biennale, inaugurata nel 2017, riunisce esperti in tecnologie del linguaggio, scienza dei dati e rappresentazione della conoscenza. Supportata da un comitato scientifico internazionale, LDK è cresciuta costantemente, con le edizioni precedenti ospitate in Irlanda, Germania, Spagna e Austria. Gli atti di questa edizione di LDK raccolgono 34 articoli e una prefazione. Ciascun articolo è stato sottoposto a revisione single-blind da almeno tre esperti. La conferenza si concentra sull’acquisizione e sull’uso dei dati linguistici in contesti scientifici e industriali, con particolare attenzione all’elaborazione del linguaggio naturale, all’apprendimento automatico e alle tecnologie semantiche. I temi principali includono grafi della conoscenza, risorse multilingue e approcci neuro-simbolici che combinano modelli linguistici di grandi dimensioni e semantica esplicita
Digital Thread Based Federated Interoperability for Complex Systems Engineering
No full textInternational audienceLarge amounts of heterogeneous data are generated, used and managed all along engineering projects. The concept of digital thread (DTH) is therefore evoked to assume digital continuity, consistency, and traceability of these data. To this purpose, this paper proposes an approach to address data, tool, and processes interoperability problems in the DTH
Proposal of a Model‐ and Pattern‐Based Method for the Engineering of a Digital Twin System
No full textInternational audienceThe engineering and maintenance in operational conditions (MOC) of a digital twin system (DTS) remains today a difficult, time‐consuming, costly and resource‐intensive task. This paper proposes a method to support the stakeholders involved in such activity. It combines the principles and processes of model‐based systems and software engineering (MBSSE), is inspired by the pattern‐based systems engineering (PBSE) approach and is in line with the recent norms and standardization. An application on a real use case of the method is presented to illustrate the practical benefits of this contribution
Antibacterial active “Non Migrating” food packaging based on chitosan-containing PLA films
No full textInternational audienceThe dominance of single-use petroleum-based plastics in food packaging is being challenged by increasing environmental concerns, driving innovation toward biodegradable, bio-based, and non-toxic alternatives. Polylactic acid (PLA) has emerged as a leading candidate due to its renewability and compostability. However, its limited ability to prevent microbial contamination has prompted the integration of antimicrobial agents into PLA-based systems. Traditional antimicrobial packaging relies on agents that diffuse through the polymer matrix, but uncontrolled migration can reduce antimicrobial efficacy and raise food safety issues. To address this, non-migrating systems are being explored. These involve the covalent attachment or immobilization of antimicrobial compounds to ensure sustained activity without migration. Chitosan, a natural biopolymer with inherent antimicrobial properties, has gained attention for its biodegradability, biocompatibility, ease of functionalization and, given its high molar mass, a very low migration rate. This review focuses on recent advances in non-migrating antimicrobial strategies, particularly those based on chitosan incorporated into PLA packaging. Innovative techniques such as surface modification, hybrid nanocomposites, and synergistic bioactive blends showing promise in enhancing the antimicrobial performance of PLA films while maintaining safety and sustainability. These developments offer a pathway toward next-generation food packaging materials that are both environmentally friendly and effective in preserving food quality and safety
A new strategy for synthesis of novel hydrazinyl pyridine hybrid for selective adsorption of Ga (III); apply for extraction from industrial ore effluents
No full textInternational audienceGallium being classified as a critical metal, its recovery from secondary sources became a strategic issue. Therefore, the sorbents design for high affinity toward gallium recovering is thus a challenge. A new sorbent was designed with high sorption affinity based on pyridine and hydrazinyl groups (HZP-GA). This offers a remarkable sorption performance at mild acid pH (≈pH 4) with maximum sorption up to 265 mg Ga g-1. The isotherms fitted by the Sips equation, while the sorption is endothermic and spontaneous. Fast sorption kinetics was detected (25 min is sufficient for complete sorption) and fitted with PFORE. Gallium sorption is easily and fast reversed; 0.3 M HCl solution, with full desorption in 20 min. A very limited loss in sorption performance after five cycles, revealed to high chemical stability. The HZP-GA shows a marked preference of Ga (III) than most other competitor ions in the solution, while the preference of trivalent metal ions was noticed over mono- and di-valent cations after investigated in equimolar multicomponent solutions. In the processing of pre-treated acid leachates of U-bearing ores; gallium has the priority for recovering at pH 4–5, which indicates that the HZP-GA reveals a promising tool for recovering of precise metals from complex natural solutions
Etude des couplages hygrothermiques au sein de pierres naturelles de construction dans le contexte de l'habitat méditerranéen.
No full textInternational audienceDans un contexte de transition écologique et d’adaptation au changement climatique, la caractérisation et la compréhension des couplages hygrothermiques des matériaux de construction constituent un enjeu majeur pour améliorer la durabilité des ouvrages et le confort des usagers. Les variations thermiques et hydriques, particulièrement dans un contexte méditerranéen soumis à des conditions extrêmes, conduisent à améliorer notre compréhension des transferts hygrothermiques couplés en situation instationnaire. Ce travail s’intéresse à la pierre naturelle, matériau géosourcé, localement disponible et historiquement utilisé en région méditerranéenne. Des campagnes expérimentales ont permis de caractériser et de déterminer le comportement hygrothermique de la pierre de Luget face aux variations de température et d’humidité relative de l’air