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Selective laser melting of regolith for optimized small objects manufacturing in a lunar ISRU context
No full textInternational audienc
Unveiling mechanical interactions between cell division and extracellular matrix in human colonic epithelium organoids: A 4D study using DVC
No full textInternational audienceAbstract Cell division is a major event in tissue homeostasis, enabling renewal and regeneration. Stem cells, in particular, play an important role in this homeostasis, thanks to their ability to perform symmetric or asymmetric cell divisions. To study cell division, the human colon epithelium represents a model of choice due to its rapid renewal and therefore high proliferative potential. Currently, studying the live mechanical interactions between the epithelium and its matrix in vivo is challenging due to the lack of suitable methods. 3D human colon organoids seeded in Matrigel® are good models for this purpose as, from isolated stem cells, they recapitulate the tissue architecture organization and properties. This culture set-up also allows to study the matrix displacements around the organoid. Here, we studied the impact of cell division within the colonic epithelium on the extracellular matrix. We performed and validated an original experimental and analytical process with a 3D time-lapse confocal microscopy to follow cell mitosis and matrix movements on which we performed Digital Volume Correlation. We showed that these two different types of cell division impact the matrix differently with the asymmetric divisions causing a mainly uniaxial displacement, whereas symmetric ones involved a multiaxial and more important one
A Methodology for Designing a Decision Support System for Hyperconnected Circular Supply Chain Network Design
No full textPart 6: Simulation FrameworksInternational audienceThe Circular Economy is one of the promising solutions to address environmental challenges, such as climate change, resource depletion, pollution, and waste. However, the implementation of the Circular Economy remains limited due to economic and financial barriers. This paper proposes to overcome these barriers by designing a decision support system for hyperconnected circular supply chain network design, leveraging opportunities offered by collaborative networks and the Physical Internet. A methodology inspired by Herbert Simon’s decision-making theory is developed, including the intelligence, design, choice, and implementation phases. Specifically, a matrix for strategic options is proposed to elaborate scenarios for the design phase. A case study on the electric retrofit ofInternal Combustion Engine vehicles illustrates the proposed methodology
Adapting chemical reaction kinetics of biomass fast pyrolysis to fluidized-bed reactor model
No full textInternational audienceFast pyrolysis has been the subject of intense fundamental research over the last 30 years. However, the bioenergy industry is still limited and needs design improvement. Improving the process requires considering biomass's thermal and chemical decomposition at the molecular scale, thermal and mass transfer at the particle scale, and fluidized bed hydrodynamics at the reactor scale. This work presents a numerical lumped model describing the fast pyrolysis of biomass. Chemical kinetics are predicted via a semi-global reaction model [1]. The stoichiometric approach ensures mass conservation. Non-isothermal and heterogeneous reactions are assumed, and the biomass sample temperature is considered. Numerical results are compared with experimental data obtained from a micro-pyrolyser coupled with a mass spectrometer [2]. Numerical results highlighted the key role played by the thermal model. The project is still an ongoing work. The long-term goal is the direct coupling of global chemical kinetics and reactor model via a stoichiometric approach to incorporate realistic molecular details. The coupling strategy will be presented
Characterization and modeling of laser transmission welded polyetherketoneketone (PEKK) joints: influence of process parameters and annealing on weld properties
No full textInternational audienceWelding high-performance thermoplastics has gained popularity across various industries such as automotive, aerospace, and medical. Laser transmission welding (LTW) has emerged as an effective method for joining thermoplastic parts due to its precise control and high joint quality. PAEK (polyaryletherketone) are wide spreading over various industrial applications as a substitute to metals and thermosets when high durability and performance are required. Polyetherketoneketone (PEKK) is one of these PAEK and it has received less attention than PEEK until now. PEKK, being a semi-crystalline thermoplastic, requires additional care during processing due to its propensity to crystallize. This study presents both experimental and numerical investigations into LTW of PEKK molded parts, aiming to understand the influence of welding parameters and crystallinity on weld joint morphology and mechanical properties. PEKK plates, prepared in amorphous and semi-crystalline states, are subjected to LTW using a 975 nm diode laser. Material characterization confirms differences in crystallinity between the samples, which affect their thermal and optical properties, which are crucial for welding. Welding tests are conducted with varying laser power (between 75 and 95 W) and semi-transparent part thickness (2 and 4 mm). The morphology of joints is analysed. Assemblies undergo post-weld annealing treatment to examine its influence on weld crystallinity and consequent mechanical properties. Results reveal an anisotropic distribution of crystallinity within the heat-affected zone (HAZ). The depths of the molten layer (ML) and semi-crystalline layer (scL) vary with laser power and assembly type. A notable decrease in weld strength with laser power is highlighted, while annealing leads to enhanced crystallinity and improved weld strength. Despite variations, high weld strengths are achieved with annealing. Computational modelling elucidates the complex interplay between laser irradiation, temperature distribution, and crystallization kinetics observed experimentally. Overall, this comprehensive investigation provides valuable insights into optimizing LTW parameters for PEKK parts
Demand estimation adapted to hyperconnected transport systems in regional areas
No full textInternational audienceRegional transportation systems face multiple challenges, including inadequate service quality and scarce and geographically dispersed demand. The Physical Internet (PI) concept offers potential solutions to these issues, yet its focus has primarily been on urban and freight-oriented contexts, overlooking the unique challenges of regional transportation. Moreover, the limited analysis of regional transportation has resulted in a lack of detailed understanding of demand dynamics and difficulties in aligning supply capabilities with demand expectations. To address these issues, this paper proposes a methodology for analyzing regional transport demand, that embraces the PI concept by treating both freight and passenger demand within a unified framework. The methodology defines user profiles, characterizes demand in terms of volume, time, and space, and identifies the factors influencing transportation use. An experimental study using the ECOTRAIN project validates the effectiveness of this approach. This case study not only shows the applicability of the methodology but also highlights its potential to guide the development of tailored transportation solutions suited to regional areas
Improving the compressibility of recycled carbon fibre non-woven mats
No full textInternational audienceThis paper looks at increasing the fibre volume fraction of composites made of recycled carbon fibres and processed through resin infusion. While the pressure applied on the reinforcement is limited to the difference between atmospheric pressure and the vacuum applied inside the cavity, different methods of increasing the fibre content were investigated, whether before or during composite manufacturing. The most effective method appeared to be through the application of a high loading on the reinforcement before draping the preform in the mould. A change of the non-woven architecture also appeared to enable a significant gain in the composite fibre content, the control of the resin infusion process also enables a gain of a few points of fibre fraction. The influence of the fibre content on the coefficient of thermal extension was also investigated and the improvement of the carbon footprint of the developed composite was estimated through the estimation of energy required to manufacture the raw materials
Modélisation des propriétés mécaniques des matériaux composites à fibres végétales
No full textInternational audienc
Towards training network resilience to maintain disaster recovery expertise
No full textInternational audienceEffective disaster recovery depends on highly-skilled practitioners. Like any sector, however, the education and training systems that build these skills can experience crises that disrupt their ability to function effectively. These can be one-off events (e.g. a major flood) or extend over long periods (e.g. a pandemic or a vocational crisis). Based on the observation that there is a shortage of trainers and teachers in the education sector, as shown by indicator D7 (OECD, 2023), in this article we study the ongoing ability of a French vocational training organization to transmit skills that are useful to society in the event of a natural disaster, and in particular those that will shorten the recovery time of buildings and infrastructures. We propose a model that simulates the flow of people through the educational system and the institution’s ability to generate enough trainers to maintain a chain of know-how transmission. In the simulation of this work in progress, we have parameterized the actual success rates, which we vary in order to define a minimum success rate limit to ensure the renewal of human capital. Based on the proposed model, further testing and analysis will be used to characterize a range of resilient flow behaviors and to provide recommendations for maintaining the condition of the human know-how transmission chain
It's a Machine Learning world: no future for Complex Event Processing?
No full textInternational audienceIn 2010, Complex Event Processing was a groundbreaking approach for data processing for Early Warning Systems and Decision Support Systems in the crisis management domain. Although Machine Learning has eclipsed CEP in the ISCRAM community these last few years, these two approaches do not fulfil the same objectives. With this article, a quantitative analysis is made on papers related to these domains to understand the current trends and identify the next challenges the ISCRAM community should address. Combining CEP with ML can help to overcome the strong assumptions made towards the CEP rules this last decade, such as the availability of experts, structured data, etc. It is then recommended that the ISCRAM community explore the hybridisation of these approaches to improve the responsiveness in real time of EWS and DSS in crisis situations, emphasising the automatic, non-supervised generation of CEP rules