HAL Portal de Univ. Gustave Eiffel
Not a member yet
72847 research outputs found
Sort by
Influence of Cell Position on the Capacity of Retired Batteries: Experimental and Statistical Studies
No full textInternational audienceUnderstanding how batteries perform after automotive use is crucial to determining their potential for reuse. This article presents experimental results aimed at advancing knowledge of retired battery performance. Three modules extracted from electric vehicles were tested. Their performance was assessed, and the results were analyzed statistically using analysis of variance (ANOVA). The 36 retired cells exhibited a high level of performance, albeit with significant variation. On average, the cells had a 95% state of health capacity with a dispersion of 2.4%. ANOVA analysis suggests that cell performance is not correlated with their position inside the module. These results demonstrate the need to evaluate dispersion within retired batteries and to develop thermal management and balancing systems for second-life batteries
Hitting Probabilities and the Ekström-Persson conjecture
No full textWe consider the Ekst\"om-Persson conjecture concerning the value of the Hausdorffdimension of random covering sets formed by balls with radii and centres chosen independently at random according to an arbitrary Borel probability measure on . The conjecture has been solved positively in the case , where stands for the upper Hausdorff dimension of . In this paper, we develop a new approach in order to answer the full conjecture,proving in particular that the conjectured value is only a lower bound for thedimension. Our approach opens the way to study more general limsup sets, and has consequences on the so-called hitting probability questions. For instance, we are able to determine whether and what part of a deterministic analytic set can be hit by random covering sets formed by open sets
From social to ‘affordable’. The financialization of publicly subsidised housing in France
No full textInternational audienc
DIM PAMIR Patrimoines matériels -innovation, expérimentation et résilience Charte de réutilisation des données du projet DEGEL
No full textDétourner la lutte contre les violences sexuelles, un stratagème efficace ?: Les conflits de pouvoir chez mouvement Emmaüs (2023-2024)
No full textInternational audienceComme d’autres préoccupations sociétales surgies avant elle, la lutte contre les violences sexistes et sexuelles au sein des entreprises est susceptible de connaître aussi bien des pratiques sincères que des détournements, soit pour des motifs de réputation institutionnelle, soit pour des usages stratégiques (inter ou intra-organisationnels).Cette contribution propose de montrer comment le levier du scandale post-#MeToo peut être mobilisé pour renverser le pouvoir dans une organisation. Pour ce faire, il s’appuiera sur une analyse des événements survenus au sein du mouvement Emmaüs sur la période 2023-2024 à l’aune des 36 stratagèmes
Analyse ergonomique de l'activité des usagers de micromobilités en situations à risque
No full textInternational audienceCe texte original a été produit dans le cadre du congrès de la Société d'Ergonomie de Langue Française qui s'est tenu à Nanterre les 2, 3 et 4 juillet 2025. Aucun usage commercial ne peut en être fait sans l'accord des éditeurs ou archiveurs électroniques. Il est permis d'en faire une copie papier ou digitale pour un usage pédagogique ou universitaire, en citant la source exacte du document, qui est la suivante : Brunet, B., Simon, N., Surmont, J., Aupetit, S. & Cabon</div
Energy and digital transition: how virtual power plants are transforming existing electricity regimes
No full textInternational audienc
Teaching soil mechanics in a changing world
No full textInternational audienceGeotechnical engineers face a changing world in which the need for new approaches in the wake of climate change presents both a challenge and an opportunity for constructing and maintaining existing infrastructures. It is thus crucial to adapt teaching soil mechanics, of which the basic concepts were established in the 20th century, to the new context. At the "École nationale des ponts et chaussées", France, the Department of Civil Engineering and Construction's students can consolidate the scientific bases of various fields while learning to be flexible and adapt to any new situation. In addition to the essential and basic concepts of standard Soil Mechanics taught in traditional lectures and hands-on sessions, two projects are introduced. The first is a literature review, allowing the students a quick global view of the current problems in Geotechnical Engineering. The second is a modelling project where the students use constitutive laws to simulate some standard laboratory tests. Besides, the contents of the Soil Mechanics class and other related classes, essentially the Geotechnical Designs class, are closely coordinated. This approach would allow graduate students to quickly learn new technologies and tools and solve problems that cannot be dealt with by standard soil mechanics knowledge
Turbulent transport extraction in time and frequency and the estimation of eddy fluxes at high resolution
No full textInternational audienceWe introduce a novel framework for estimating eddy fluxes using cross-scalogram smoothing, addressing key limitations of the standard eddy-covariance method. The standard approach suffers from fixed averaging times (typically 30 min) and limited frequency resolution, which can lead to biases and an inability to capture fast dynamics. Our method, based on wavelet transforms, allows for high-resolution analysis of fluxes in both time and frequency domains. It adaptively localises turbulent scales using a metric derived from the vertical component of the Reynolds stress tensor, enabling more accurate flux estimation under varying turbulence conditions. The proposed metric is similar to the u* and σw tests, but it is adapted to the time–frequency setting. By decoupling the filtering of perturbative scales from flux calculations, our approach allows for flexible averaging times. This adaptability makes it particularly suitable for studying rapid ecosystem responses to environmental changes, such as those occurring on timescales shorter than 1 h. We show application of the framework at the beech forest site Hesse (code FR-Hes) and demonstrate its relation with standard eddy-covariance calculations. The proposed method allows for varying the averaging time without impacting the filtering of the perturbative scales. It thus allows for producing estimates of CO2, latent heat, and sensible heat fluxes with faster dynamics (e.g. with 1, 10, and 30 min averaging time). We present statistics of the 10 min averaged fluxes and show that they align well with estimates of the 30 min standard eddy-covariance method. The improved localisation of turbulent scales results in higher estimates of carbon uptake during summer (+2 ± 1 µmolm-2s-1) and a more accurate assessment of nighttime respiration compared to standard eddy-covariance estimates. The methodology is implemented in the Julia package TurbulenceFlux.jl, making it readily accessible for practical applications