Portail des publications scientifiques IMT Mines Alès
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Ingénierie Système au fil des exigences - Processus d'évaluation : outils
No full textDoctoralEvaluation process and its role in system engineering. Relationship between requirements and evaluation. Objectives and fundamental concepts of evaluation. Evaluation tools and techniques.Processus d'évaluation et place de l'évaluation dans le cadre de l'ingénierie système. Relation entre exigences et évaluation. Finalités et concepts fondamentaux de l'évaluation. Outils et techniques d'évaluation
Solid-state tailored silver nanocomposites from chitosan: Synthesis, antimicrobial evaluation and molecular docking
No full textInternational audienceThis study thoroughly explores the synthesis, characterization, and antimicrobial efficacy of three α-aminophosphonate-chitosan (α-AP-Cs) compounds and their nano‑silver functionalized organic hybrids. α-AP-Cs derivatives (CU, CT and CSC) were synthesized via an in-situ, one-pot reaction using chitosan and triphenyl-phosphite, with different carbamide-glutaraldehyde crosslinkers; urea-glutaraldehyde, thiourea-glutaraldehyde and semicarbazide-glutaraldehyde, respectively. Subsequently, their corresponding α-AP-Cs‑silver nanocomposites (CU-Ag0NPs, CT-Ag0NPs and CSC-Ag0NPs) were synthesized via solid-state approach. Their physicochemical and morphological profiles were fully characterized and compared against chitosan-Ag0NPs (Cs-Ag0NPs) and their bare organic-cores via CHNS/P/O, FT-IR, XRD, TEM, EDX, XPS and UV–visible analysis. The synthesis procedure, including phosphonation and carbamide-glutaraldehyde crosslinking, was confirmed through spectroscopic and elemental analyses. XPS and XRD affirmed the metallic silver with FCC structure. The UV–visible absorption peak was ⁓399 nm with averaging TEM size of the semi-spherical Ag0NPs around 30.4 nm. Thereafter, antimicrobial properties were systematically explored and optimized by evaluating minimum inhibition concentration, dose-killing, growth kinetics curves, protein leakage, and antibiofilm activity against bacterial strains (Streptococcus mutans and Pseudomonas aeruginosa) and fungal strains (Candida albicans and Rhizopus oryzae). Notably, incorporating α-aminophosphonate and Ag0NPs into chitosan-backbone markedly enhanced its antimicrobial efficacy against bacterial and fungal biofilms. Finally, a detailed structure-activity relationship study was conducted to elucidate the antimicrobial mechanisms
Assessing to act: A water-energy-food-ecosystem (WEFE) nexus governance assessment for the Inkomati-Usuthu river basin in South Africa
No full textInternational audienceWater, energy, food, and ecosystems (WEFE) are inherently interlinked, forming a complex system (nexus) that is shaped by natural and anthropogenic factors. The nexus concept was introduced as a holistic approach to resource governance. Yet, many studies remain rather technical and governance and policy-related questions often unanswered. This paper presents a WEFE nexus governance assessment for the Inkomati-Usuthu river basin in South Africa. The assessment is based on interviews and workshops with stakeholders from the four WEFE sectors and local, regional and national levels. Using the WEFE nexus governance assessment tool NXGAT, we evaluated the current governance system along five governance dimensions (actors and networks, levels and scales, problem perspectives and goal ambitions, strategies and instruments, and responsibilities and resources) and five governance quality criteria (comprehensiveness, coherence, flexibility, intensity of action, and fit). Our results show that the current governance system of the Inkomati-Usuthu river basin is moderately restrictive towards WEFE nexus governance, in particular due to the poor performance of the governance quality criteria comprehensiveness, coherence, and intensity of action. We give practical recommendations for nexus-oriented actions that can be implemented as key steps towards WEFE nexus governance. Subsequently, we reflect on our methods and discuss limitations of our study. We conclude that a WEFE nexus governance assessment based on stakeholder experiences and knowledge provides valuable insights and contributes to broader efforts to enable more contextualised assessments
Direct determination of turbulent burning velocity during aluminum flame propagation: comparison of three experimental methods
No full textInternational audienceBurning velocity is a key parameter of main flame propagation models. However, its experimental determination while studying propagating dust flame is still challenging. In this work, aluminum flame propagation in a vertical tube is studied. Two aluminum powders with median diameters of 6.2 and 20.7 μm are analyzed for different equivalence ratios with air. The main objective of this work is to compare the methods commonly used in the literature to determine the burning velocity in the case of propagating flames. One of these methods is based on the estimation of the thermal expansion coefficient. This article focuses first on the estimation of this coefficient and presents the limits of considering the adiabatic flame temperature for its estimation. As detailed in the paper, these methods have some limitations and are therefore compared with an innovative method based on a local direct determination of the burning velocity. This local method is based on the measurement of the unburned flow velocity just ahead of the propagating flame front by Time-Resolved Particle Image Velocimetry (TR-PIV). The methods commonly used in the literature mainly underestimate the burning velocity when compared with the local method. The local method is then used to study the influence of the particle size distribution and the equivalence ratio on the turbulent burning velocity. Firstly, we observe that the turbulent burning velocity increases while the flame is propagating in the vertical tube. Furthermore, the turbulent burning velocity with the 6-μm powder is higher than with the 20-μm powder
Minér’Alès : Un événement transversal autour des collections de géologie d’IMT Mines Alès (Gard)
No full textInternational audienceGrâce à l’initiative de la directrice d’IMT Mines Alès et des géologues responsables des collections, les collections géologiques de l’Ecole, reconnues comme un patrimoine référencé dans l’inventaire national du patrimoine géologique sous le numéro OCC0049 et comprenant 12 000 minéraux, 2 000 fossiles et 600 roches, sortent progressivement de leurs réserves.C’est en ce sens que l’évènement annuel Minér’Alès fut initié en 2023 durant lequel une partie des collections géologiques de l’école sont exposées dans un site de l’agglomération d’Alès pour une dizaine de jours avec en parallèle des balades géologiques, des conférences, des ateliers pour lesfamilles et pour les scolaires. Cet évènement est notamment l’occasion de présenter les projets "arts et sciences " développés durant l’année.Depuis plusieurs années, une collaboration s’est instaurée entre IMT Mines Alès et l’École Supérieure des Beaux-Arts de Montpellier. En 2025, l’exposition "Illuminations" a poursuivit cette dynamique en s’appuyant sur la collection géologique d’IMT Mines Alès, ainsi que sur lesaffleurements de charbon, pour permettre aux étudiants du MO.CO. Esba d’explorer de nouvelles formes artistiques. Ces pierres, témoins de notre passé et de notre avenir, offrent des clés pour mieux comprendre l’art, ses couleurs et ses formes, tout en stimulant l’imagination et lasensibilité.En 2025 également une collaboration entre IMT Mines Alès et la Mission arts et culture de la DSDEN du Gard a permis aux classes ayant travaillé sur le thème des " cailloux " en arts plastiques de mettre en valeur leurs créations à travers une exposition intitulée " pierres remarquées, pierres remarquables ". Cela représente une occasion marquante dans le cadre du Parcours d’Éducation Artistique et Culturelle pour les élèves. Ainsi, une douzaine de classes issues de quatre écoles ont saisi cette opportunité et ont présenté leurs œuvres.L’événement Minér’Alès illustre comment l’alliance entre la Géologie et l’Art, en lien avec les collections d’IMT Mines Alès, les affleurements ou des simples " cailloux ", peut donner lieu à des créations remarquables et transversales, captant ainsi un large éventail de publics qui en règle générale interagissent peu
Geospatial analysis and modeling of the distribution of Lassa fever and the pattern of spread in Nigeria
No full textInternational audienceLa fièvre de Lassa est une maladie hémorragique virale aiguë, causée par le virus de Lassa par ingestion ou inhalation, et se transmet principalement à l'homme par contact avec des aliments ou des articles ménagers contaminés par les excréments ou l'urine de rongeurs infectés, en particulier le rat multimammate. Cette recherche vise à trouver des solutions et à guider les décideurs dans l'atténuation de la propagation de la fièvre de Lassa. Cette recherche explore le potentiel de la cartographie géospatiale et de la modélisation de l'intelligence artificielle pour illustrer les schémas de propagation du virus Lassa et les zones sensibles en Afrique de l'Ouest, afin de recommander un système de quarantaine complet dans les ports et aux frontières pour limiter la propagation du virus Lassa.L'objectif de cette recherche est de développer un modèle basé sur le SIG pour identifier la propagation et la dynamique de la fièvre de Lassa. Elle vise également à identifier les zones à haut risque de transmission de la fièvre de Lassa en fonction de facteurs environnementaux et socio-économiques. Évaluer l'efficacité des contrôles existants pour améliorer la prévention de la fièvre de Lassa et atténuer la propagation sporadique en Europe, aux États-Unis et en Asie. À la fin de la recherche, nous serons en mesure d'identifier les facteurs socio-économiques et environnementaux qui contribuent à la transmission de la fièvre de Lassa. L'intégration du SIG et de l'IA permet de créer des cartes de risque qui prédisent la probabilité d'apparition de la fièvre de Lassa à temps. Nous pourrons également formuler des suggestions et des recommandations
Enhancing Flash Flood Forecasting and Understanding Hydrosystem Dynamics for Small Urban Basins in the framework of Explainable Artificial Intelligence– Case Study of the Cadereau d'Alès, Nîmes
No full textInternational audienceMediterranean basins are particularly exposed to flash floods caused by intense rainfall. Nîmes city, located in southern France, is frequently affected by these events, which cause significant damage and casualties. These floods are exacerbated by climate change and rapid urbanization. Addressing these challenges, decision-makers and managers require efficient flood forecasting models to optimize their crisis management strategies. However, traditional hydrological models often struggle to accurately predict such extreme events. In this context, artificial neural networks (ANNs) provide a promising alternative due to their ability to model complex nonlinear dynamics, making them particularly suitable for hydrological modeling and flood forecasting. In this study, a model based on multilayer perceptron was applied to simulate flash floods in the Alès Cadereau in Nîmes city, while extending the lead time. The KnoX method, a Physics Informed Machine Learning (PIML) method, was employed to extract internal information from the model, enhancing its interpretability and acceptability in operational contexts. The results demonstrate remarkable performance across various lead times, with criteria values indicating the reliability and accuracy of the proposed models. Contributions of input variables, calculated using the KnoX method, provide relevant and coherent insights consistent with the physical processes of the modeled basin. This approach highlights how prior knowledge can effectively guide ANN models to produce results in line with the physical processes of the basin
Post-CHF nuclear fuel operation with Time-at-Temperature criteria
No full textInternational audienceThe dryout and departure from nucleate boiling criteria are used to set safety limits on nuclear heat transfer and temperature values in nuclear reactors. This review argues for the use of a Time-at-Temperature criterion to improve efficiency and utilization of nuclear fuels and reduce costs. To illustrate the importance of such criteria, the review presents the different phenomena of cladding and fuel rods that could impact the continued operation of nuclear reactors, as well as the experiments and operating events that occurred in light-water reactors
Durability, mechanical recycling and environmental impacts of poly-lactic acid (PLA) based natural fiber reinforced composites: Effect of reactive agents and fiber surface treatment
No full textInternational audienceThis study presents the recyclability analysis of PLA/flax and PLA/bamboo biocomposites comprising silane treated fibers with and without the addition of a chain extender agent. To assess their mechanical recyclability, PLA biocomposites were reprocessed using multiple cycles of hygrothermal ageing, grinding process, followed by injection molding. The environmental impact of producing the biocomposites on a laboratory scale was evaluated by a life cycle assessment (LCA). An ecodesign approach was adopted to identify hotspots in the production process. The influence of fiber treatment with and without the addition of Joncryl ™ as a reactive chain extender agent, on the properties of the biocomposites after reprocessing cycles was evaluated by examining changes in the molecular structure and physico-mechanical properties of the samples. In general, the study showed that all biocomposites exposed to hygrothermal ageing, grinding and the re-injection process underwent a chain scission mechanism which was responsible for the decrease in average molecular weight, thermal stability and tensile properties. However, fiber treatment with silane and the addition of Joncryl™ helped to limit these effects. LCA results showed that fiber treatment was the most impactful stage, followed by PLA production. Despite the fact that it exhibits poorer mechanical properties after recycling cycles, the PLA/bamboo biocomposite has a smaller environmental footprint than the PLA/Flax biocomposite. This discrepancy arises from variations in both the biomass cultivation conditions and the subsequent processing steps, including fiber treatment and compounding in an internal mixer. Recycling PLA/Flax or Bamboo biocomposites beyond the third and second recycling stages, respectively, is not recommended
