Portail des publications scientifiques IMT Mines Alès
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Interoperability at the heart of digital twin for better decision making
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Caractérisation perceptive des sons de lauzes de couverture
No full textInternational audienceLes toitures en lauzes calcaires constituent un élément caractéristique de l’architecture vernaculaire et patrimoniale des régions montagneuses de la France, en particulier des Causses et Cévennes, dont l’utilisation connaît actuellement un important regain d’intérêt. Dans sa pratique traditionnelle, l’artisan lauzier prépare et diagnostique les pierres qu’il taille en les faisant sonner de coups secs, dans le but de choisir celles qui seraient susceptibles de résister durablement aux conditions climatiques hivernales sévères de cette région (alternance de gel et de dégel associée à des variations d’humidité). Il prend ainsi des décisions en fonction d’informations sonores et contextuelles (taille, lieu, couleur, nature géologique, etc.). Cette pratique, peu documentée et dont le pronostic est parfois erroné, à tout intérêt à être consolidée scientifiquement et valorisée. Des essais en laboratoire permettant de simuler sur un temps accéléré la situation de terrain ont été réalisés, et une méthodologie de suivi non-destructif de l’endommagement d’échantillons de lauzes calcaires à partir de leur réponse mécanique vibratoire impulsionnelle a été validée. Nous souhaiterions à présent enrichir ces résultats basés sur des analyses physiques par une étude perceptive destinée à identifier les critères qui influencent la décision du lauzier. Un corpus de sons de lauzes de géométrie identique comportant différentes caractéristiques géologiques et microstructurales a été enregistré. Lors d’un test perceptif, des stimuli sonores, accompagnés d’images de lauzes et d'informations sur leur provenance sont utilisés. Nous recueillons les décisions prises par le lauzier, ainsi que le vocabulaire utilisé pour caractériser chaque pierre. Les résultats de cette catégorisation perceptive seront ensuite comparés à ceux d’une analyse acoustique, afin d’associer chaque verbalisation à des critères objectifs. Les résultats de cette étude devraient permettre de mieux comprendre cette pratique et de préserver le savoir-faire de la filière professionnelle concernée
Use of biopolymers in wastewater treatment: A brief review of current trends and prospects
No full textInternational audienceIndeed, polymeric materials have thrived in worldwide sectors over the last five decades due to their versatility and durability, to the point that we can no longer envisage a product that does not contain them. However, many synthetic polymers that have been produced are mostly sourced from petroleum and coal as raw materials, making them environmentally incompatible because they cannot be integrated with what is a natural recycling system. One of the most important aspects of the transition to a circular bioeconomy (CBE) is the provision of more sustainable strategies for resource and waste management. Considering the environmental consequences associated with petroleum-based polymers (PBPs), natural biopolymers, originating from biomass, can be conceived as a promising solution to gradually replace the PBPs, and address, and resolve the potential challenges and prevailing research gaps in the PBPs. The biopolymers have significant advantages over PBPs in terms of low-cost/zero-cost precursors, environmental friendliness, and user-friendliness. The present review dissects the sources, synthesis pathways, structures, characterization, and employment of biopolymers and their composites in water and wastewater treatment applications via different scenarios. Furthermore, the CBE model framework proposes potential approaches to applying CBE principles in the wastewater management sector, with a heavy emphasis on not only technology but also organizational and societal reforms. To sum up, the reliance on biopolymers can be considered a crucial tool for assessing the global progress toward CBE, as well as future environmental management and planning
Novel method for synthesizing high S-bearing hybrid sorbent for efficient silver binding – Characterization, testing, and application to metal recovery from X-ray films
No full textInternational audienceThe reaction of thiocarbazide with pentaerythritol tetrakis(3-mercaptopropionate) in the presence of mesoporous silica beads allows producing a composite sorbent (PTMF-SiO2) with high affinity for silver. The high density of both N- and S-based reactive groups (about 5 mmol g−1) explains sorption capacities as high as 3 mmol Ag g−1 at pH 6. The sorption mechanisms are correlated to the pH effect, and to FTIR and XPS spectroscopic analyses. The sorption is endothermic and spontaneous, and the sorption isotherms are successfully modeled using the Temkin equation. Uptake kinetics are fitted by the pseudo-first order rate equation: the equilibrium is reached in 20–30 min. Ultrasonic treatment allows slightly increasing both kinetics (apparent rate coefficient k1 is almost doubled) and sorption capacities (by less than 7 %). Silver (being a soft acid) preferentially reacts with soft bases; this may explain the selective removal of Ag(I) by PTMF-SiO2 against base metals and alkali or alkaline earth metals (in multicomponent equimolar solutions). The sorbent shows remarkable recycling stability (for at least 5 cycles): complete desorption is achieved in ≈20 min with 0.3 M HNO3 solution and the loss in sorption does not exceed 2.5 % at the fifth recycling. Finally, the sorbent is successfully applied to silver recovery from acidic leachates of spent X-ray films (from different hospitals from Hengyang, China), as a case study. Silver is selectively recovered with high efficiency (>96 %) (together with Cu(II), to a lesser extent)
Accelerated weathering influence on natural fibers and their composites
No full textInternational audienceRenewable lignocellulosic fibers are used more and more in the preparation of eco-friendly materials. Among the existing natural resources, the use of a sterile and non-invasive crop namely miscanthus x giganteus (MxG) [1] is of great interest and could be used in PP polymeric matrix as a green material design perspective. Hence, the present work aims to investigate the consequence of the chemical composition on the color modification of MxG in comparison to flax fibers and their incorporation in a commercial stabilized PP-based blue matrix using an accelerated artificial UV weathering up to 20 weeks. Results using a spectrophotometer show a lightening effect for native and extractive-free flax and darkening for native and extractive-free miscanthus. This behavior could be related to fibers cracking caused by the elimination of degradation products as confirmed by SEM observations. The impact on color perception is also related to the lignin content which is much important for miscanthus (23 wt%) compared to flax (9 wt%). Indeed, lignin is subjected to photocleavage and its transformation to colored chromophore groups (e.g. quinoids) or uncolored groups (e.g. quinoids transformation into carboxylic acid) [2] as confirmed by the ATR-FTIR analysis. Delignified fibers yellowing is related to residual lignin and holocelluloses photochemical degradation. Native and extractive-free PP composites show color enlightenment and disappearance of superficial black spots. These dark spots present before weathering are less important for miscanthus and seem to be caused by a higher thermal degradation of flax during the transformation process. This is explained by the better thermal stability of the miscanthus fibers as confirmed by TGA analysis which led to better color stability than flax. Delignified miscanthus and flax fibers composites show better color stability compared to the pure PP-based stabilized matrix
Rouvrir des mines en France: l’acceptabilité sociale est-elle vraiment la bonne question?
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Assessing the Impact of Wait Times on Patient Mortality Outcomes in a Hypothetical Oil and Gas Industry Disaster Scenario: An Agent-Based Modeling Approach Using NetLogo
No full textInternational audienceBackground:Emergency response in the oil and gas industry entails the efficient coordination and execution of human and material resources to lessen the effects of a disaster while simultaneously protecting both life and critical assets.Objective: Model, simulate, and implement hospital system interactions in emergency response scenarios in the oil and gas industry using Agent-based modelling and simulation.Motivation: Challenges in emergency settings, including interaction, lack of real-time data sharing and analysis, and need for patient safety in a complex and dynamic environment, for:▪ Enhancement of response coordination in emergency;▪ Assessment of impacts of key factors in emergency respons
A systemic, model and data-based method for depollution projects engineering and management
No full textInternational audienceDecision-makers are struggling to design and manage depollution projects all along their duration, facing various events and challenges. So, they need approaches allowing them to act. In general, existing approaches focus on costs optimization and deadlines management but remain not entirely adapted for depollution context and objectives. In particular, multiple, heterogeneous and independent enterprises are generally involved in such projects. Indeed, they provide each particular capabilities (e.g. mastering depollution techniques), resources and means to perform some depollution activities that are requested as a whole and during various time period. However, they need to interact with each other, having and sharing in confidence a good understanding. They need a common point of view and vocabulary about the whole project itself, of concerns of all its stakeholders, about its current state of development, of the first obtained results and so on. There is then a need to assist and support actors who are in charge of depollution projects to engineer and manage such projects and address all these challenges: complexity, heterogeneity, multiplicity of interactions and actors. This paper proposes and argues the value of a collaborative and model-based method aiming to specify, check then control and adapt dynamically depollution projects. As a consequence, this method intends to move from an artisanal depollution approach to a standardized vision of the depollution
Incorporation of Fly Ash in Flame-Retardant Systems of Biopolyesters
No full textInternational audienceThe incorporation of fly ash in polybutyl succinate (PBS) and polybutyl adipate terephtalate (PBAT) in the partial replacement of ammonium polyphosphate and/or melamine polyphosphate is evaluated in the present work. Furthermore, the influence of the surface modification of fly ash with two silanes and titanate coupling agents was also studied. Cone calorimeter experiments, pyrolysis combustion flow calorimeters (PCFCs), and UL94V tests were used to assess the fire performance of the composites. Scanning electronic microscopy, X-microanalysis, and X-ray diffractometry analysis were carried out on cone calorimeter residues in order to access the fire-retardant mode of action. The formation of new components due to the presence of fly ash was highlighted by X-ray diffractometry, indicating the synergistic effects between the flame-retardant system and fly ash. The X-microanalysis results showed that the main fraction of initial phosphorous is present in the cone calorimeter residue, indicating that the proposed system acts in a condensed phase
