Portail des publications scientifiques IMT Mines Alès
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Synergistic Fusion of Simulation and Virtual Reality: A Proposed New Approach for Collaborative Integration
No full textInternational audienceThis paper presents a comprehensive comparative analysis and a new proposed approach for the integration of Discrete Event Simulation (DES) with Virtual Reality (VR) environments, focusing on addressing challenges encountered in prior architectural approaches. These challenges include redundant environmental design efforts in both DES and VR, the establishment of a unified reference point spanning both architectures, resource allocation concerns, limitations in graphical interfaces, extended development timelines, and heightened network resource consumption. The central aim of this project is to offer effective remedies for overcoming these obstacles, thereby enhancing the overall efficiency of distributed DES/VR environments. It introduces an innovative architecture and approach to mitigate the identified challenges. The proposed method seeks to streamline simulation design, optimize resource allocation, standardize the integration of simulation and VR components, enhance network communication between the VR and DES components, and reduce the time required for DES model development. Experimental results validate the efficacy and efficiency of the proposed solution in effectively addressing the aforementioned challenges
Advances in the Production of Cellulose Nanomaterials and Their Use in Engineering (Bio)Plastics
No full textInternational audienceThis chapter provides a comprehensive review of the processes used to deconstruct cellulosic fibers into cellulose nanomaterials (CNM) and their use in one of the most promising applications, namely, engineered (bio)plastics. We focus on the preparation of CNM via chemical and enzymatic pretreatments and discuss the most recent developments in related areas. The mechanical processes used to isolate CNM are described, with an emphasis on their effect on morphological and strength development. We also provide a comparative analysis of the industrialization potential of the most important methods to incorporate CNM in polymeric matrices. Classical and emerging uses of CNM in engineering (bio)plastics are presented, considering (i) CNM dispersion in polymer matrices to develop nanocomposites and, (ii) CNM adsorption at interfaces in polymer blends and composites to build hierarchical structures. The dispersion/orientation state of CNM in such materials and the underlying physical–chemical phenomena related to interfacial interactions between CNM and the polymer phase are discussed. The latter takes into consideration the impact of CNM on the development of functional materials. Overall, this chapter offers essential knowledge to facilitate the conversion of cellulosic fibers into CNM and their implementation in the field of composites
Flax Shives As Fillers For Injection Molded Bio-Based Composites
No full textInternational audienceFlax shive is the main by-product for flax fiber production. It represents about 50% of the weight of the dry flax stem. Its low price (around 100 €/t) and its very low bulk density (100 to 140 kg/m3 [1]) attracts its use as? an alternative bio-based filler in bio-composite materials. Recent studies have shown a significant effect of flax shives granulometry on the tensile properties of the composite. Therefore, this study aims to further investigate the influence of the size and shape distributions of flax shives on the mechanical behavior of the composite and interpret the results through microstructural analysis. Different fractions were prepared by grinding and sieving to obtain these particle sizes: less than 200 µm, 200-500 µm, 500-800 µm and 800-1600 µm. Flax shive / polypropylene (PP) composites were prepared using twin-screw extrusion and injection molding with fiber weight fractions of 10%, 20%, 30%, and 40%. Maleic anhydride grafted polypropylene (MAPP) was used as a compatibilizer with an optimized ratio. Figure 1a presents the tensile properties of the resulting composites, revealing that flax shives sieved between 200 and 500 µm provide the optimal tensile properties. Microstructure analysis showed that better fiber dispersion and higher interfacial area (shown in Figure 1b) are obtained for composites reinforced with low fiber granulometry. The aspect ratio of the particles was determined after solvent extraction of flax shives from the composite. X-ray tomography (shown in Figure 1c) provided additional data regarding the orientation and the distribution of the flax shives in the composite. Microstructural data were then used to predict the mechanical behavior of the composites and estimate the Young’s modulus of the flax shive through both Mori-Tanaka analytical model and finite element analysis
Editorial: Deep learning for multimodal brain data processing and analysis
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Développement de nouveaux traitements ignifuges, déperlants et antisalissures pour textiles à base de fibres de lin
No full textThe textile industry produces functional fabrics with specific physical and chemical properties to provide anti-perspirant, anti-UV, antibacterial, water repellency, self-cleaning and flame retardancy performances to satisfy the market needs. Nowadays, the use of natural fibers (cotton, flax, silk and wool) as alternatives to synthetic fibers has become a solution of great interest due to their low environmental impact. However, the chemical composition of natural fibers present some problems such as their flammability and their hydrophilicity. These drawbacks require their chemical modification in order to achieve some applications. The chemical modification method used in this study was the radiografting and more precisely the pre-irradiation process.In this work, flax fabrics were modified by grafting phosphorus flame retardants and fluorinated monomers in order to improve their fire behavior and hydro-oleophobicity. The effect of different parameters such as the irradiation dose, the structure and concentration of the monomer, the reaction time and temperature on the grafting efficiency has been studied.The functionalization of flax fibers using different phosphonated and fluorinated monomers was assessed by infrared spectroscopy, elemental analysis (ICP-AES), X-ray fluorescence and scanning electron microscopy (SEM) coupled with an energy dispersive X-ray detector (EDX). The fire behavior of the modified fabrics was investigated using thermogravimetric analysis, pyrolysis-combustion flow microcalorimetry and cone calorimetery. The contact angles measurement was used to evaluate the hydrophobicity and oleophobicity properties of the modified samples after. Multifunctional flame retardant and hydro-oleophobic fabrics were successfully developed using the combination of multiple monomers during the radiografting process.L’industrie textile produit aujourd’hui des tissus fonctionnels qui possèdent des propriétés physiques et chimiques spécifiques qui leur permettent d’atteindre des performances anti-transpirantes, anti-UV, antibactériennes, imperméables, autonettoyantes ou ignifuges pour répondre aux besoins du marché. Aujourd’hui, l’utilisation de fibres naturelles (coton, lin, soie et laine) comme substituants de fibres synthétiques est devenu une solution d’un grand intérêt du fait de leur faible impact environnemental. Cependant du fait de leur composition chimique, les fibres naturelles présentent certains inconvénients tels que leur inflammabilité ou leur hydrophilie. Ces faiblesses nécessitent donc leur modification chimique pour permettre d’atteindre certaines applications. La méthode de modification chimique employée dans cette étude a été le radiogreffage et plus précisément la méthode de pré-irradiation.Dans ce travail de thèse, des tissus de lin ont été modifiés par greffage des retardateurs de flamme phosphorés et de monomères fluorés afin d’améliorer leur comportement au feu et leur hydro-oléophobie. L’influence de différents paramètres du procédé tels que la dose d’irradiation, la nature et la concentration en monomère, le temps et la température de réaction sur l’efficacité du greffage ont été étudiés.La fonctionnalisation de tissus de lin par différents monomères phosphorés et fluorés a été évaluée par spectroscopie infrarouge, analyse élémentaire (ICP-AES), fluorescence X et microscopie électronique à balayage (SEM) couplée à une sonde de rayons X à dispersion d’énergie (EDS). Le comportement au feu des tissus obtenus a été étudié par analyse thermogravimétrique, microcalorimétrie de combustion et cône calorimètre. La méthode de mesure des angles de contact a également été utilisée pour évaluer les propriétés d’hydrophobie et d’oléophobie des échantillons après modification. Des tissus multifonctionnels à la fois ignifuges et hydro-oléophobes ont été développés avec succès par combinaison de plusieurs monomères durant la réaction de radiogreffage
Environmental and economic assessment integrated into laboratory-based scenario development for the valorization of dredged sediment
No full textInternational audienceThis study discusses the potential environmental and economic benefits of dredged sediment valorization in concrete in the framework of the circular economy. The goal is to find a sustainable way to use the sediment in concrete while maintaining its strength and not compromising the economy or environment. The maximum rate of sand substitution in concrete with sediment was found to be 40%, but sustainability was negated for rates above 20%. To optimize sustainability, a compromise between concrete strength and workability, economic and environmental impacts, and sediment transport must be reached. Lack of environmental and economic assessments in valorization scenarios may lead to non-sustainable practices
In-situ monitoring of changes in ultrastructure and mechanical properties of flax cell walls during controlled heat treatment
No full textIssu de : https://doi.org/10.2139/ssrn.4404621International audiencePlant fibres are increasingly used as reinforcements, especially in thermoplastic composites. Understanding the impact of temperature on the properties of these fibres is an important issue for the manufacturing of high-performance materials with minimal defects. In this work, the structural evolution and mechanical behaviour of flax fibre cell walls were dynamically monitored by temperature-controlled X-ray diffraction and nanoindentation from 25 to 230 °C; detailed biochemical analysis was also conducted on fibre samples after each heating step. With increasing temperature up to 230 °C, a decrease in the local mechanical performance of the flax cell walls, of about −72 % for the indentation modulus and −35 % for the hardness, was measured. This was associated with a decrease in the packing of the cellulose crystal lattice (increase in d-spacing d200), as well as significant mass losses measured by thermogravimetric analysis and changes in the biochemical composition, i.e. non-cellulosic polysaccharides attributed to the middle lamellae but also to the cell walls. This work, which proposes for the first time an in-situ investigation of the dynamic temperature evolution of the flax cell wall properties, highlights the reversible behaviour of their crystalline structure (i.e. cellulose) and local mechanical properties after cooling to room temperature, even after exposure to high temperatures
Probing the Promises of Noninvasive Transcranial Electrical Stimulation for Boosting Mental Performance in Sports
No full textInternational audienceWhile the importance of physical abilities is noncontested to perform in elite sport, more focus has recently been turned toward cognitive processes involved in sport performance. Practicing any sport requires a high demand of cognitive functioning including, but not limited to, decisionmaking, processing speed, working memory, perceptual processing, motor functioning, and attention. Noninvasive transcranial electrical stimulation (tES) has recently attracted considerable scientific interest due to its ability to modulate brain functioning. Neuromodulation apparently improves cognitive functions engaged in sports performance. This opinion manuscript aimed to reveal that tES is likely an adjunct ergogenic resource for improving cognitive processes, counteracting mental fatigue, and managing anxiety in elite athletes. Nevertheless, the first evidence is insufficient to guarantee its real effectiveness and benefits. All tES techniques could be add-ons to make performance-related cognitive functions more efficient and obtain better results. Modulating inhibitory control through tES over the frontal cortex might largely contribute to the improvement of mental performance. Nevertheless, studies in elite athletes are required to assess the long-term effects of tES application as an ergogenic aid in conjunction with other training methods (e.g., neurofeedback, mental imagery) where cognitive abilities are trainable
Immersive Innovation: Exploring Interactive Virtual Reality through Distributed Simulations
No full textInternational audiencerious sectors, focusing particularly on distributed simulation (DS). The increasingimportance of DS has been emphasized in response to evolving industrial, healthcare,and services settings. By leveraging DS, the integration of heterogeneous simulationsenhances the effectiveness and efficiency of individual and classical simulations. Inparticular, this chapter introduces a DS that seamlessly combines two distinct simulationmethods within a virtual reality (VR) environment. This integration enables usersto fully immerse themselves in a 3D digital twin environment. Two case studies wereconducted to evaluate the effectiveness of the developed DS system. The first casestudy focused on the implementation of DS in a hemodialysis unit, while the secondcase study examined its application in an intensive care unit. AnyLogic has beenutilized for developing both discrete event and agent-based simulations, while theUnity platform has been employed for VR environment creation. In order to ensuresmooth integration and synchronization, as well as address the demanding computationalrequirements, a network-based DS system has been implemented based on thehigh-level architecture—an IEEE standard for DS