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Applications of rhamnolipid surfactants in agriculture
No full textInternational audienceRhamnolipids are glycolipid biosurfactants naturally produced by Pseudomonas and Burkholderia bacteria, wellknown for their surface-active properties and eco-friendly advantages. Indeed, these compounds efficiently reduce the surface and interface tensions, possess potent biological activities against pathogens, and display low toxicity. Rhamnolipids thus hold significant promise for various industrial applications, including agriculture, which is in need of a transition to greener and more sustainable practices by reducing synthetic inputs. This review describes the knowledge about the antimicrobial properties of rhamnolipids against different phytopathogens, mainly fungal species, as well as their ability to trigger plant defense mechanisms and phytoprotection efficacy in different species. The recent literature investigating rhamnolipids as potential plant biostimulation agents, thanks to their abilities to improve soil health and plant tolerance to abiotic stresses, is also addressed. Finally, the prospect of rhamnolipids as a biopesticide and their overall contribution to sustainable agricultural practices is discussed
Gestion des réseaux de communication complexes avec l'IA distribuée : Défis et perspectives ouvertes
No full textThe rapid evolution of communication networks, particularly with the introduction of 5G and the anticipated arrival of 6G, has introduced new complexities in managing traffic, routing, and resource allocation. Distributed Artificial Intelligence (DAI) is emerging as a promising solution to address challenges related to scalability, adaptability, and performance in these dynamic environments. With the unpredictable nature of network traffic patterns and the dynamic infrastructure of modern networks, effective network management is crucial for ensuring optimal resource utilization and preventing congestion. This is essential to maintain high performance, reliability, and scalability in today's communication systems. This paper explores the application of AI techniques in network management, with a focus on key areas such as congestion control, routing management, and traffic prediction. By examining both centralized and distributed AI approaches-such as Multi-Agent Reinforcement Learning (MARL) -it highlights their potential to enhance network efficiency, improve latency, increase throughput, and reduce packet loss. The paper also addresses the limitations of current methods, while discussing potential future directions for AIdriven solutions in large-scale, real-time network operations
Parametric Life Cycle Assessment (LCA) of Power Modules
No full textThis paper was presented at the EPE 2025 conference and was subsequently selected for publication in the special issue of Elsevier's PEDC journal. Therefore, only the abstract appears on the conference website.International audiencePower Electronics is a key factor in the electrification of our modern society. In the attempt of massive decarbonation, this fastgrowing industry is going to put pressure on the environment. Life Cycle Assessment is used to identify the main impacts of products and services. The paper presents an open-source method to carry on a parametric LCA of power modules to help power electronics designers and engineers assess the environmental impacts of such devices when used in power converters. After recalling how is derived the open access LCI of a type of power modules, the method to implement Parametric LCA for this kind of device is introduced. It is then applied on a specific case study for automotive applications and main LCA results are provided to illustrate the method. The last section is dedicated to introduce several perspectives and applications of Parametric LCA to support ecodesign
A System-of-Systems Approach to Flexible Job-Shop Scheduling Using Column Generation
No full textInternational audienceIn the era of smart manufacturing, scheduling techniques play a crucial role in optimizing industrial processes. Among the various scheduling problems, the Flexible Job-Shop Scheduling Problem (FJSSP) represents a fundamental challenge due to the diversity of machines and production chains. The simultaneous management of routing and scheduling significantly increases complexity, making exact optimization methods impractical for large instances. This paper proposes a column generation approach to efficiently explore the solution space and improve makespan while significantly reducing computational time. The method iteratively refines the solution by generating promising columns, ensuring a trade-off between optimality and efficiency. Preliminary tests on medium and large instances, considering equivalent processing times, demonstrate that the proposed approach achieves near-optimal solutions at a considerably higher speed compared to traditional methods. These results highlight the potential of column generation as a viable strategy for addressing large-scale FJSSP instances in industrial applications
Analyse et caractérisation du transport pneumatique de solides non-conventionnels
No full textPneumatic conveying is used to transport divided solids in many industrial processes. This technology is well developed and the operation is generally well controlled when dealing with regular or “conventional” granular materials (e.g., granules, pellets, ores). However, the behavior during the transport of irregular or “unconventional” materials (e.g., biomass, waste, recycled materials) is still poorly understood. These materials present many difficulties during their handling, due to their heterogeneity in terms of physical and behavioral properties, which can cause blockages and unscheduled stops. To address this issue, it is imperative to provide a better understanding of the link between the physical characteristics of the particles and the macroscopic hydrodynamic behavior of these materials during pneumatic conveying. In this study, a pilot-scale pneumatic conveying system was installed and adapted in order to experimentally study the flow of different granular materials (“conventional” and “unconventional”). The materials were transported under different operating conditions. The pressure drop/gas velocity diagrams were plotted for the different materials and the results were modelled. To estimate the particle velocity during transport, a high-speed camera was used and the optical flow technique was applied. In addition, a numerical study of pneumatic conveying was conducted using the CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) method, in order to simulate the experiments carried out and provide a better understanding of the phenomena involved. The transport of the reference materials was modeled by considering them as spherical particles. A sensitivity study was carried out to evaluate the influence of the different simulation parameter, like the friction coefficients and drag force models. The effect of the operating conditions, particularly the solid flow rate and the gas velocity, was analyzed numerically, as well as the effect of the solid properties. The validity of the results from the simulations was verified by comparison with the experimental data, in particular the pressure drops in the different sections. This work sets the base for future work on biomass and waste issued solids pneumatic conveying at UTC.Le transport pneumatique est fréquemment utilisé pour transporter des solides divisés dans de nombreux procédés industriels. Cette technologie est bien développée et l’opération est globalement maitrisée lorsqu’il s’agit de matériaux granulaires réguliers ou « conventionnels » (e.g., granulés, pellets, minerais). Cependant, le comportement lors du transport de matériaux irréguliers ou « non-conventionnels » (e.g., biomasse, déchets, matériaux recyclés) est encore mal connu. Ces matériaux présentent de nombreuses difficultés lors de leur manipulation, en raison de leur hétérogénéité en termes de propriétés physiques et comportementales, pouvant provoquer des blocages et des arrêts intempestifs. Pour répondre à cette problématique, il est impératif d’apporter une meilleure compréhension du lien entre les caractéristiques physiques des particules et le comportement hydrodynamique macroscopique de ces matériaux lors du transport pneumatique. Durant cette étude, un système de transport pneumatique à échelle pilote a été installé et mis au point afin d’étudier expérimentalement l’écoulement de différents matériaux granulaires (« conventionnels » et « non-conventionnels »). Les matériaux ont été transportés dans différentes conditions opératoires. Les diagrammes perte de charge/vitesse du gaz ont été tracés pour les différents matériaux. Pour estimer la vitesse des particules lors du transport, une caméra rapide a été utilisée et la technique du flot optique a été appliquée. De plus, une étude numérique du transport pneumatique a été menée en utilisant la méthode CFD-DEM (Computational Fluid Dynamics-Discrete Element Method), afin de simuler les expériences réalisées et apporter une meilleure compréhension des phénomènes mis en jeu. Le transport des matériaux de référence a été modélisé en les considérant comme des particules sphériques. Une étude paramétrique a été effectuée pour évaluer l’influence des différents paramètres. L’effet des conditions opératoires, particulièrement du débit de solide et de la vitesse du gaz, a été analysé numériquement, ainsi que l’effet des propriétés du solide. La validité des résultats issus des simulations a été vérifiée par comparaison avec les données expérimentales, notamment les pertes de charge dans les différentes sections. Ce travail pose les bases des travaux futurs sur le transport pneumatique des solides issus de la biomasse et des déchets à l'UTC
Large graph limits of local matching algorithms on Configuration model graphs
No full textIn this work, we propose a large-graph limit estimate of the matching coverage for several matching algorithms, on general graphs generated by the configuration model. For a wide class of local matching algorithms, namely, algorithms that only use information on the immediate neighborhood of the explored nodes, we propose a joint construction of the graph by the configuration model, and of the resulting matching on the latter graph. This leads to a generalization in infinite dimension of the differential equation method of Wormald: We keep track of the matching algorithm over time by a measure-valued CTMC, for which we prove the convergence, to the large-graph limit, to a deterministic hydrodynamic limit, identified as the unique solution of a system of ODE's in the space of integer measures. Then, the asymptotic proportion of nodes covered by the matching appears as a simple function of that solution. We then make this solution explicit for three particular local algorithms: the classical greedy algorithm, and then the uni-min and uni-max algorithms, two variants of the greedy algorithm that select, as neighbor of any explored node, its neighbor having the least (respectively largest) residual degree
Stochastic modeling of movement for Helium particles in a graphite channel
No full textInternational audienceIn this article, we present a stochastic model for the movement of Helium particles within a graphite channel, focusing on Knudsen diffusion. We develop a semi-Markov model to describe the movement of the particle, derive the stationary distribution of its mean position, and analyze the model's asymptotic properties. To validate the model, we compare its theoretical outcomes with Monte Carlo simulations. As temperature significantly influences on the movement of particles, two situations are studied for high and low temperature. In both cases, theoretical and simulation results by Monte Carlo coincide. Furthermore, we propose estimation methods for the local parameters of the model and demonstrate its application using data from Molecular Dynamics simulations.</div
Former les futurs ingénieurs aux enjeux environnementaux
No full textInternational audienceFormer les futurs ingénieurs aux enjeux environnementau
Rates for the SLLN for long-memory and heavy-tailed processes
No full textInternational audienceAbstract The present paper develops a unified approach when dealing with short- or long-range dependent processes with finite or infinite variance. We are concerned with the convergence rate in the strong law of large numbers (SLLN). Our main result is a Marcinkiewicz–Zygmund law of large numbers for , where is a real stationary Gaussian sequence and is a measurable function. Key technical tools in the proofs are new maximal inequalities for partial sums, which may be useful in other problems. Our results are obtained by employing truncation alongside new maximal inequalities. The result can help to differentiate the effects of long memory and heavy tails on the convergence rate for limit theorems
A Rocq Formalization of Simplicial Lagrange Finite Elements
No full textThe finite elements method is a popular method to numerically solve partial differential equations. In the long-term goal of proving its correctness, we focus here on the formal definition of what is a finite element: a record in the Rocq proof assistant with both values and proofs of validity, including the main one called unisolvence. We then instantiate this record with the most popular and useful, the simplicial Lagrange finite elements for evenly distributed nodes, for any dimension and any polynomial degree. These proofs require many results (definitions, lemmas, canonical structures) about finite families, affine spaces, multidimensional polynomials, in the context of finite or infinite-dimensional spaces