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Application of null-collision backward Monte Carlo algorithm to digital image rendering of sooting flames in the visible range
No full textInternational audienceThe objective of this work is to present a new tool to produce a digital image computation inside asooting flame using Monte Carlo methods. The studied case consists of a laser emission corresponding to aspatially localized source of collimated radiation, that partially illuminates the environment. The laser emissionconsequently causes problems of convergence with a Monte Carlo method due to the difficulty in statisticallylinking sensors to sources. A new algorithm has been proposed to calculate the radiative intensity at a givenprobe position. An open source tool has been developed based on a combination of Null Collision Algorithms(NCA) with hierarchical grids technics from the computer graphics community, allowing to perform efficientradiative transfer (and possibly produce images). These tools are generic and are able to accept any inputdata such as, for instance, temperature and concentration fields produced by a Large Eddy Simulation (LES)approach over a tetrahedral grid. We show in this paper a first monochromatic digital image of a laminarsooting flame in the visible range. Such a new tool can for instance provide a useful support for experimentalcharacterization of the radiative behavior of soot aggregates in flames, such as tracking effects of scattering
Towards a Demand Estimation Framework applied to Hyperconnected Transport Systems in Regional Areas
No full textInternational audienceThis paper proposes a modular, utility-based demand estimation framework tailored to hyperconnected regional transport systems, inspired by Physical Internet (PI) principles. By treating both passenger and freight flows as standardized Logistic Units (LUs), the framework unifies diverse mobility needs into a single decision-support model. It dynamically adjusts user preferences across multiple criteria: cost, time, emissions, comfort, reliability, and safety, and evaluates transport demand under varying service conditions. The approach is structured in three phases: independent demand modeling, transport network integration, and utility-drivendemand allocation. Eight experimental scenarios are developed, combining trip variability, vehicle availability, and utility calculation methods. Applied to the ECOTRAIN project in the Occitanie region of France, the framework models eleven user profiles across six transport modes. The study demonstrates how PI-aligned, data-driven modeling can support strategic, tactical, and operational decisions for more inclusive, sustainable, and efficient regional mobility
Effect of cooling rate on metastable zone width of glycerol derived from sunflower oil and compressed oil
No full textInternational audienceGlycerol is a commonly utilized compound in numerous industrial and consumer products, wherein crystallization is crucial in identifying product quality. The metastable zone width (MZW) is an important parameter in crystallization and phase transformation, needed for process control. The MZW is affected by factors such as cooling rate, which directly influences crystallization behaviour and the performance of the final product. Despite its significance, research on the MZW of glycerol is limited to emphasize the necessity for additional study. Metastable zone temperature (MZT) and induction time of glycerol from sunflower oil and compressed oil were discovered throughout the studies. Simultaneously, gravity settling was used to separate glycerol from the biodiesel obtained via the transesterification process. To determine the MZW, Crystal 16 was used for the analysis. The most stable MZT for glycerol from sunflower oil was attained at 10 ℃/h, while the optimal induction time was recorded at a rate of 15 ℃/h. Meanwhile, the most stable MZT for compressed oil was obtained at a rate of 10 ℃/h and the optimal induction time was observed at a rate of 20 ℃/h. In conclusion, the study of the MZW of glycerol is important for optimizing the crystallization process and enhancing process control and product quality for industrial applications
Facing Climate Change: How to Manage the Arising New Crises?
No full textInternational audienceThe increasing frequency and intensity of climate change-related disasters highlight the need to develop adaptive crisis management approaches. This paper explores the integration of R-IO Suite, a knowledge-based decision support system, with GAMA, a multi-agent simulation platform, to improve situational awareness and crisis response in a changing climate. This approach enables decision-makers and local communities to better understand, anticipate, and mitigate crisis impacts by combining real-time data modelling and predictive simulation. Although the proposed framework has been conceptually defined, its implementation and validation remain open key challenges. The French ANR-funded ATEsT project aims to overcome major technical obstacles— interoperability, semantic alignment, and temporal synchronisation—through concrete use cases. Future work will focus on implementing and testing this integration in realistic crisis scenarios, such as mega-fires and flash floods across different territories, to assess its effectiveness in improving decision-making processes and citizen engagement
DAEM_MC: Distributed Activation Energy Model by Monte Carlo
No full text`DAEM_MC` is a Monte-Carlo estimator of the reaction rate based on the DAEM (Distributed Activation Energy Model). The project aim to reproduce the results of the article: A Monte-Carlo Based Strategy to Assess Complex Kinetics: Application of the Null-Reaction Method to DAEM"
Lien procédé-microstructure-propriétés de composites oxyde/oxyde élaborés par imprégnation de mèches en continu
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Oxygen Ingress in Titanium and Its Alloys After High-Temperature Oxidation: A Competition Between Strengthening and Embrittlement
No full textInternational audienceHigh-temperature oxidation of titanium leads to the formation of an external oxide scale and oxygen ingress into the metallic titanium material. Oxygen ingress can be significant due to the high solubility of O within Ti. An oxygen-rich layer (ORL) thus forms beneath the external oxide scale, exhibiting a brittle behavior. Microtensile specimens were used in order to exacerbate surface effects, i.e., surface reactivity in the case of the oxidation of titanium. Playing with the specimen thickness and pre-oxidation durations, it was possible to evaluate the evolution of tensile strength as well as the reduction in ductility for deep extensions of ORL relative to the specimen thickness (high fraction of ORL). In addition, ultrathin specimen extraction at different locations within the ORL depth aimed at better identifying the gradient of properties within the ORL. This micromechanical approach was applied to a commercially pure titanium (CP-Ti grade 2) and to a structural titanium alloy (Ti6242s). Both strengthening and loss of mechanical properties (yield strength and ductility) were observed depending on the material and oxygen ingress. While CP-Ti demonstrated an increase in mechanical strength up to ORL representing 80 pct of the gage section, Ti6242s experienced a loss of mechanical resistance even for the shortest exposure times (the ORL representing 10 pct of the gage section)
A Guiding Framework for Hyperconnected Circular Supply Chain Implementation
No full textInternational audienceThis paper addresses the critical need to incorporate Circular Economy principles into supply chain management for decoupling economic growth and resource consumption. Circular supply chains, characterized by their restorative and regenerative nature, inherently introduce operational complexities. Concurrently, hyperconnectivity is evolving as a pervasive reality, defined by the extensive and intricate interconnectedness among actors across multiple layers. Specifically, we investigate the potential of the Physical Internet, a hyperconnected global logistics system, to facilitate the implementation of circular supply chains. Our approach includes a systematic literature review to map the current landscape and the development of a novel conceptual framework. This framework, merging the Physical Internet and circular supply chain concepts, identifies ten interrelated characteristics from various aspects such as product design, production, logistics, supply chain asset utilization, product usage, recovery, performance monitoring, material and energy exchange, as well as technology and business model innovation. Additionally, we introduce a four-stage maturity model to evaluate and improve companies' circular supply chain practices systematically. Its practical application is illustrated through two cases in automobile and sport garment industry respectively. This study is among the first to explore the integration of hyperconnectivity in logistics management into implementing circular supply chains. It lays a theoretical foundation and suggests actionable strategies
A new device for monitoring deformation dynamics and droplet shrinkage kinetics (during drying) of a charged droplet suspended in air
No full textInternational audienceIn this study, a new device was developed to study the deformation kinetics of a pendant droplet under controlled drying conditions and in the presence of an electric field (EF). It has made it possible to investigate the deformation and air-drying kinetics of conductive and electrically charged pendant CuSO4.5H2O droplets. Various EF intensities (0–800 kV/m) and solid content concentrations (0–25 % wt/wt) are applied. Results show significant reduction (up to 42 %) in interfacial tension with increasing EF, along with a quadratic relationship between EF intensity and interfacial tension. Droplet surface area expansion and deformation are influenced by the EF intensity and the solution solids content. It has also been shown that, during drying, EF application can influence the deformation kinetics and shrinkage rate during the early drying stages, particularly at higher solid concentrations and high EF intensity, revealing new insights into droplet dynamics under EF