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Exploring the use of recycled coarse aggregates from different sources in Self-Compacting Concrete for sustainable building
No full textInternational audienceThe construction industry depends heavily on Natural Aggregates (NA), leading to major environmental and economic issues due to extraction costs and resource loss. Recycled coarse aggregates (RCAs) from Non-Harmful Construction and Demolition Waste (NHCDW) are the best alternative for Self-Compacting Concrete (SCC). This study looks at the performance of SCC using different types of recycled gravels from NHCDW, such as concrete, bricks, bitumen, roof tiles, and plastics (PVC). The fresh and hardened states of SCC were analyzed, with measurements taken for workability, porosity, density, and mechanical strength. The findings indicated that the substitution of recycled gravels resulted in adequate performance, except when 85% of recycled brick gravel was replaced with natural gravel. However, a slight decrease in mechanical strength was observed for all mixes. The results indicated that SCC with up to 85% recycled concrete coarse aggregates maintained satisfactory rheological and mechanical properties. However, replacing 85% natural gravels with recycled bricks gravels led to an 18.5% reduction in mechanical properties compared to the reference, failing to meet the requirement. In general, the mechanical strengths, including compressive, and tensile strength decreased by 8.8% to 18.5% and 9.2% to 14.8 % respectively, compared to the reference. These findings provide valuable insights into the limited values of coarse aggregates from NHCDW materials for concrete purposes. This study is part of the work in the European project 101091679-MOBICCON-PRO (MOBile and Innovative Circularity for Construction Products) framework-Horizon-Cl4-2022-Twin-Transition-01. This research aids sustainable construction by providing guidelines for using RCA in concrete, which lowers environmental impact and supports the circular economy
Search for in situ signatures of electric activity on Mars
No full textInternational audienceElectrical discharges such as lightning are among the most energetic and remarkable phenomena in planetary atmospheres. Both laboratory experiments and modeling studies have predicted that triboelectric charging of wind-blown particles in dust events on Mars should lead to significant electrification. However, there have been no direct measurements of a Martian electric field or observations of discharges. Here, using acoustic recordings from the SuperCam microphone onboard the Perseverance rover, we report evidence for an atmospheric discharge in a dust devil, based on the electromagnetic and acoustic signatures observed in the microphone signal. This is the first direct detection of a triboelectric discharge in the Mars atmosphere. It shows that the electric field in a dust devil can reach 25 kV/m, which is the expected breakdown threshold of the Mars atmosphere. Electrical discharges on Mars may have implications for dust dynamics, the chemistry of oxidants and methane in the atmosphere, and ultimately robotic and human exploration
Une division sociale du travail qui ne dit pas son nom. Gouverner les émotions, incarner une politique locale
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Distinct functions of cardiac β-adrenergic receptors in the T-tubule vs. outer surface membrane
No full textInternational audienceβ-adrenoceptors (β-ARs) regulate cardiac function during sympathetic nerve stimulation. β-ARs are present in both the cardiac T-tubule (TTM) and outer surface membrane (OSM), but how their location impacts their function is unknown. Here, we developed a technology based on size exclusion to explore the function of β-ARs located in the OSM. We synthetized a PEG-Iso molecule by covalently linking isoprenaline (Iso) to a 5000 Da PolyEthylene-Glycol (PEG) chain to increase the size of the β-AR agonist and prevent it from accessing the T-tubule network. The affinity of PEG-Iso and Iso on β1- and β2-ARs was measured using radioligand binding. Molecular dynamics simulation was used to assess PEG-Iso conformation and visualise the accessibility of the Iso moiety to water. Using confocal microscopy, we show that PEGylation constrains molecules outside the T-tubule network of adult rat ventricular myocytes (ARVMs) due to the presence of the extracellular glycocalyx. β-AR activation in OSM with PEG-Iso produced a lower stimulation of [cAMP]i than Iso but a larger stimulation of cytosolic PKA at equivalent levels of [cAMP]I and similar effects on excitation-contraction coupling parameters. However, PEG-Iso produced a much lower stimulation of nuclear cAMP and PKA than Iso. Thus, OSM β-ARs in ARVMs control mainly cytosolic cAMP/PKA pathway and contractility, while TTM β-ARs control mainly nuclear cAMP, PKA and consequent nuclear protein phosphorylation. Size exclusion strategy using ligand PEGylation provides a unique approach to evaluate the respective contribution of T-tubule vs. outer surface membrane proteins in cardiac cells
Mineurs non accompagnés : l'absence de photographie ne suffit pas à écarter la force probante des actes d'état civil étrangers
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Autorité parentale : quelle exigence quant à l'impartialité du juge ?
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Multi-Agent Multi-Armed Bandits: application to EVs smart charging with grid constraints
No full textInternational audienceElectrification of energy uses with renewable sources is a major lever of decarbonization. To maximize the use of renewable energy, and tackle its variability and uncertainty, flexible entities such as electric vehicles can be used. This paper presents a scalable, decentralized multi-agent system, where eachelectric vehicle (EV) seeks the best instants to charge to satisfy its mobility needs, while favoring photovoltaic energy and avoiding congesting the electric network. Each EV makes autonomous de-cisions using information from its environment, using contextual multi-armed bandit algorithms based on Thompson sampling. Four types of bandit-based algorithms are compared to a baseline through simulations with 55 homogeneous EV agents, achieving a distance of only 14% from an optimal omniscient centralized algorithm. The system’s real-world practicality is demonstrated through minimal computational requirements (200 μs per EV per timestep) and limited information sharing, maintaining user privacy while effectively managing grid congestion
How to identify factors influencing mode choice behaviors within a heterogeneous metropolitan area? A novel approach midway between data science and econometrics
No full textInternational audienceEstimating factors influencing mode choice behaviors has posed a significant challenge for decision makers. In this paper, we propose a three-step method to estimate mode choice between public transportation and private vehicles within a heterogeneous metropolitan area. First, we implement a deep learning model, Altaïr, capable of inferring travel times and travel flows by leveraging multi-source input data (Step 1). To identify homogeneous sub-regions regarding mode choice behaviors, two data clustering models are performed: k-means and a Gaussian Mixture Model (GMM, Step 2). The GMM reveals three spatial clusters based on the relationships between relative travel times and relative travel flows in public transportation and private vehicles. Moreover, an econometric model (robust ordinary least squares) is employed to identify additional explanatory variables, including sociodemographic features and location variables (Step 3). This hybrid method is currently employed in the Paris metropolitan area (France). At the metropolitan level, we find that competitive travel times in public transportation lead to higher ridership. Conversely, when the time ratio exceeds approximately 3.5–4, public transportation use becomes negligible in comparison to private vehicles. This hybrid method allows for precise, interpretable prediction of mode choice between public transportation and private vehicles. The method's results are close to those of the regional Household Travel Surveys (HTS), as shown in a validation analysis. The design ensures the transferability of the method to any metropolitan area, including areas with incomplete data
Concepts issus de la TSD pour le formateur et en formation dans les travaux de la COPIRELEM
No full textInternational audienceL'objectif de cet atelier est d'interroger la manière selon laquelle des concepts issus de la théorie des situations didactiques (TSD), plus ou moins développés et explicités, peuvent servir de points d'appui pour la formation des professeurs des écoles. Pour ce faire, nous présentons un cadre d'analyse qui mobilise des concepts de la TSD et nous le mettons en oeuvre sur une situation de formation emblématique des situations développées par la COPIRELEM, la situation Concertum (Péault et Butlen, 2003)
Empowering Neurodiversity: Rethinking interaction with children with Autism Spectrum Disorder through robotic mediation
No full textInternational audienceSocial robots help improve engagement in children with autism but are often poorly adapted to real-world conditions in care centers. Their humanoid form, intended to promote acceptance, can instead create rejection. Also, their price is a real obstacle to their use. Consequently, our poster presents the MR2S (robotic mediation in healthcare) project, which aims to design a non-anthropomorphic robot, developed in collaboration with professionals. Our goal is to make a robotic object that is easy to use and tailored to the diverse sensory needs of children with ASD. The focus is on social behaviour rather than appearance, and on customisable tactile interaction