Portail des publications scientifiques IMT Mines Alès
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Vers une modélisation multi-échelles du comportement mécanique du périnée
No full textNational audienceLes dysfonctions et anomalies du tissu pelvien sont responsables de nombreuses consultations et interventions chirurgicales chez la femme au cours de sa vie et de la grossesse ; elles sont principalement attribuées à la dégradation ou à l'évolution de ses propriétés biomécaniques. Pour le clinicien, il est essentiel de connaître le comportement mécanique de ce tissu afin d'anticiper sa dégradation. L'objectif de ce travail est de proposer une modélisation de ce tissu en le considérant de façon simplifiée comme un matériau multicouche. La modélisation s'appuie sur les résultats de tests de traction large instrumentés avant rupture couplés à des essais de relaxation réalisés à des paliers de déformations réguliers sur de périnées de cochons à partir desquels sont prélevés des échantillons de peau, de tissus conjonctifs et de muscles de sphincters anaux. Ces différents tissus peuvent être modélisés à travers un comportement hyperviscoélastique avec des paramètres de viscosité déterminés à chaque palier de déformation marquant l'évolution de la microstructure des tissus avec la déformation équivalente. Une méthode de recalage par éléments finis est utilisée pour déterminer les paramètres du modèle pour chacun des tissus testés. Une modélisation simplifiée du comportement hyperviscoélastique du périnée est alors proposée
Penser la trans-formation de la formation: introduire la connaissance complexe, reliante et noétique
No full textpublication pour la Revue Interventions Economiques, numéro spécial Edgar MorinInternational audienceThe aim was to provide some understanding elements of the crisis based on the complex thinking developed by Edgar Morin, taking as a basis the necessary trans-formation of training. Understanding the crises that are sweeping the world implies thinking about them according to the principles of systemic, hologrammatic, retroactive and recursive loops, autonomy and dependencies, dialogy and the reintroduction of the knowledgeable into knowledge. It's this last principle that has led us to question the reform of training through a knowledge of the inner obstacles to knowledge, a complex noetic knowledge.Cet article se propose d'apporter des éléments de compréhension de la crise à partir de la pensée complexe développée par Edgar Morin, en prenant appui sur la nécessaire trans-formation de la formation. Comprendre les crises qui traversent le monde implique de les penser selon les principes systémique, hologrammatique, de boucle rétroactive et récursive, d'autonomie et de dépendances, dialogique et par la réintroduction du connaissant dans la connaissance. C'est ce dernier principe qui nous a conduit à interroger la reforme de la formation par une connaissance des obstacles intérieurs à la connaissance, une connaissance complexe noétique
Monitoring global changes and water management strategies in Mediterranean mountain environments: hydro-socio-eco-meteorological observations in the Cévennes Mountains (Southeast France)
No full textInternational audienceCévennes mountains and its piedmont are Mediterranean environments extending from 1700 meters summits to coastline. The climate is characterised by summer droughts that last several months and extreme rainfall events occurring in autumn and spring. Current climate predictions point to an intensification of these extremes events. To assess the impact of these changes, our scientific community have been deploying a wide range of measurements and experiments to monitor environmental variables. Rainfall and discharge times series are monitored since the 50’s; chemical, ecological and social parameters were gradually added to enhance the monitoring. The monitored ecosystems range from mountain pastures and forests in the Cévennes mountains to crops, scrubland, badlands, karst caves and urban environments in the piedmont.Under climate and global change, the Cévennes socio-ecosystems suffer from water scarcity and sometimes poor water quality. We are setting up socio-eco-hydrological observatories to monitor the adaptative evolution to these issues. This set up began 15 years ago with the study fo flash floods risk and matter transport risk awareness and human behaviours during and between hydroclimatic crises (HydroPop and HyMeX projects). The ongoing socio-eco-hydrological monitoring is co-constructed with citizens and local policymakers in order to use science to advise decision making toward durability and resilience.Most of our sites are part of OZCAR-RI and RZA LTER infrastructures. They are part of the upcoming eLTER platform P3M : Mediterranean Plain, Piedmont and Plateau.In addition to long-term monitoring, this sites are privileged supports to test new measurement techniques and build interdisciplinary and participatory research projects. We welcome collaborations and provide a local expertise to projects requiring sites in Mediterranean mountains
A new simple statistical method for the unsupervised clustering of the hydrodynamic behavior at different boreholes. Analysis of the obtained clusters in relation to geological knowledge
No full textInternational audienceKarst aquifers are complex and linked to numerous management issues, particularly concerning the the risk of flooding or the availability of water resources. In view of the associated stakes, it is necessary to have the best possible knowledge of the hydrodynamic behavior of these aquifers. In this context, a semi-automated unsupervised clustering of the hydrodynamic behavior at different piezometers has been developed. It was applied to the Cadarache site of the the French Alternative Energies & Atomic Energy Commission (CEA) in South-East of France; site which is subject to rapid groundwater floods. At the methodological level, this paper proposes a grid for the interpretation of sorted water levels in relation to the hydrogeological properties of the formations. The results of this study, achieved on 75 boreholes, allows identifying several clusters of boreholes. Three clusters appeared to be representative of specific areas. The method only uses sorted graphs of water levels. A relevant relation between each cluster and its geological structure is highlighted. This study revealed the role of preferential flow paths of NW-SE and NE-SW lineaments previously identified by regional tectonic or structural studies and with same directions than fractures observed at local scale (borehole core)
Using shallow neural networks with functional connectivity from EEG signals for early diagnosis of Alzheimer's and frontotemporal dementia
No full textInternational audienceIntroduction: Dementia is a neurological disorder associated with aging thatcan cause a loss of cognitive functions, impacting daily life. Alzheimer’s disease(AD) is the most common cause of dementia, accounting for 50–70% ofcases, while frontotemporal dementia (FTD) affects social skills and personality.Electroencephalography (EEG) provides an effective tool to study the effects ofAD on the brain.Methods: In this study, we propose to use shallow neural networks applied totwo sets of features: spectral-temporal and functional connectivity using fourmethods. We compare three supervised machine learning techniques to the CNNmodels to classify EEG signals of AD / FTD and control cases. We also evaluatedifferent measures of functional connectivity from common EEG frequency bandsconsidering multiple thresholds.Results and discussion: Results showed that the shallow CNN-based modelsachieved the highest accuracy of 94.54% with AEC in test dataset whenconsidering all connections, outperforming conventional methods and providingpotentially an additional early dementia diagnosis tool
Contribution of a Risks Management method for depollution projects based on MBSE approach
No full textInternational audienceThis paper addresses the challenges in risk management of complex depollution systems, marked by intricate interactions and emergent behaviors. The objective is to develop a comprehensive approach to risk management, accounting for the system's complexity and interconnectedness throughout the depollution project lifecycle. By employing a Model-Based Systems Engineering (MBSE) method using metamodels and models, the representation and analysis of multidisplinary components and their interactions are streamlined. The depollution system is modeled with stakeholders integrated as agents using Domain Specific Modeling Language (DSML). MBSE enables the examination of internal interactions and the evaluation of feasibility. Ultimately, this work aims to enhance depollution management by helping stakeholders assess feasibility, cost, and delay of depollution processes by effectively addressing risk management
Des résines alkydes hydrides aux propriétés ignifugeantes pour la formulation de revêtements
No full textInternational audienceAn oligomer containing phosphorus and silicon (DOPO-VMDMS) has been synthetized and grafted to theremaining hydroxyl groups of alkyd resins in order to obtain hybrid alkyd resins with flame retardant properties.Silicon-alkyd resins have demonstrated better drying time, gloss and chemical resistance than alkyd resins withoutDOPO-VMDMS. The thermal and flame retardancy properties have been investigated through differential scanningcalorimeter, thermogravimetric analysis and pyrolysis-combustion flow calorimeter. The alkyd resins were appliedas a coating on a wood surface and fire behavior was tested by cone calorimeter analysis.Un oligomère contenant du phosphore et du silicone (DOPO-VMDMS) a été synthétisé et greffé sur des résinesalkydes afin d’obtenir des résines alkydes hybrides aux propriétés ignifugeantes. Les résines silicone-alkydes ontdémontré un meilleur temps de séchage, une meilleure brillance et une meilleure résistance chimique que lesrésines alkydes sans DOPO-VMDMS. Les propriétés thermiques et ignifugeantes ont été étudiées à l’aide d’uncalorimètre différentielle à balayage, d’une analyse thermogravimétrique et d’un microcalorimètre à combustion.Les résines alkydes ont été appliquées sous forme de revêtement sur une surface en bois et le comportementau feu a été testé par analyse au cône calorimètre
State-of-the-art Analysis of Cyberattack Trends in the Healthcare Sector
No full textInternational audienceOver the past few years, cyberattacks have grown increasingly complex and severe, with attackersadopting more dynamic and sophisticated tactics to breach security systems and compromise sensitivedata. The healthcare industry in particular has been one of the most targeted by cyberattacks, asmalicious actors recognize the potential vulnerabilities and immense value of the sensitive data withinthis sector. The objective of this study is to examine publicly available cyberattack databases in thehealthcare sector and perform a state-of-the-art analysis on their implementation standards. Thisinvestigation will center on the methodology used to populate the database, the guiding principles thatinform the database design, and the scope of its coverage. Adopting a database approach to cybersecurityenables a comprehensive overview of the general threat landscape, including common attacks that posechallenges to the healthcare industry. The insights gathered from this knowledge base can bolster theefficiency of artificial intelligence and provide stakeholders with valuable information on the evolvingnature of cyberattacks within healthcare. Armed with these insights, stakeholders can better appreciatethe risks they face and take proactive measures to mitigate them
Use of fly ash as synergistic and reactive component of flame retardant system in polylactide
No full textInternational audienceFor a long time, fly ash has been considered as pure waste of coal power plants. Nevertheless, unique properties and compositions that vary with the material's origin make fly ash appealing as an engineering material in various applications. Thus, the opportunity to reduce the environmental footprint of polylactide through the incorporation of fly ash as a component of flame retardant systems has been investigated. Combinations of fly ash with ammonium polyphosphate and/or melamine polyphosphate were made for a global loading of 25 wt% with various rates of substitution of the flame retardants. Fire performance has been studied from cone calorimeter experiments as well as the use of pyrolysis combustion flow calorimeter (PCFC) and the UL94V test. The interpretation of the fire retardant mechanisms has been performed through the examination of cone calorimeter residues by scanning electronic microscopy, X-ray microanalysis, X-ray diffraction (XRD) and multinuclear solid-state NMR. It can be shown that fly ash is mainly composed of spherical particles which are thermally stable at cone calorimeter tests when used alone in PLA. Conversely, fly ash behaves as a reactive component with both flame retardants, leading to the formation of new crystalline and amorphous compounds as shown by XRD and NMR. Synergistic effects in fire performance resulting from the reactive behavior of fly ash can be highlighted and are ascribed to fire retardant mechanisms acting in the condensed phase, and corresponding to the conservation of high phosphorus contents in the condensed phase
Fire behaviour of EPDM/NBR panels with paraffin for thermal energy storage applications. Part 1: Fire behaviour
No full textInternational audienceIn this work the fire behaviour of elastomeric panels made of an Ethylene-Propylene Diene Monomer (EPDM) rubber filled with a shape-stabilized paraffin with a melting point of 28 °C and covered with a nitrile-butadiene rubber (NBR) envelope, developed for thermal energy storage applications, was investigated for the first time. The panels were prepared using four different flame retardants (FR) and in order to test their efficacy they were dispersed selectively only in the core material, or in the envelope or in both of them. Cone calorimeter and epiradiateur tests pointed out the efficacy of the clay used for the shape stabilization of paraffin and of the external NBR envelope. Moreover, it was possible to demonstrate that a flame retardant based on ammonium polyphosphate and aluminium diethyl phosphinate could achieve the best fire performances. It was also verified that the combination of the FR both in the core and in the envelope led to the best results thanks to the physico-chemical and chemical interactions between clay, talc, kaolin and silicon with ammonium polyphosphate. The best composition allowed to decrease the peak of the heat release rate (HRR) from 318 kW/m2 to 209 kW/m2 and the MARHE (parameter describing the intensity of the combustion over the whole process of thermal degradation) from 239 kW/m2 to 175 kW/m2. Moreover, regarding the ability to self-extinguish, the number of ignitions at epiradiateur test was increased from 4 to 8 within 5 min and the total combustion time from 391 to 288 s. The improvement of the fire behaviour of EPDM/NBR panels with paraffin makes possible future applications in the field of thermal energy storage of buildings