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Exploring microplastics sources in indoor environments, an emerging pollutant
No full textInternational audienc
Couplage itératif d’une plaque FEM 2D à un treillis de poutre SEM
No full textVibro-acoustique : session générale; GVB - Vibro acoustique et Contrôle du BruitNational audienceLes contraintes d’urbanisation actuelles amènent à construire les bâtiments de plus en plus près des axes de transport (routier, ferroviaire, etc.). Cette tendance pose de nombreux nouveaux défis en matière de contrôle de la gêne vibratoire, notamment le besoin de modèles moins lourds que les éléments finis (FEM) tout en conservant la description du comportement physique des structures. Une solution consiste à utiliser des éléments spectraux (SEM) afin de réduire le nombre de nœuds dans le système. Si leur efficacité a été prouvée pour un treillis de poutres, la représentation d’un bâtiment réel nécessite l’ajout de planchers à cette structure de base. Pour limiter le temps de calcul, un couplage itératif est proposé, basé sur la reconstitution des champs de déplacements. Le travail présenté se concentre sur les questions soulevées par le couplage considéré linéique dans l’état de l’art, entre une plaque FEM 2D et un élément de poutre 1D. La question de la convergence de l’algorithme itératif est également abordée
HIBOU 2030: an integrated method for the Hybrid assessment of the Interactions between the BiOdiversity, the nature-based solutions, and the Urban system
No full textInternational audienceThe objective of this paper is to present the integrated method HIBOU 2030, which is employed to assess the efficiency of the Nature-Based Solutions (NBS) and their alternatives (e.g. grey, hybrid solutions) for urban projects. The HIBOU 2030 method aligns with international initiatives, such as the Science-based targets Network for nature[1] that promote the integrated assessment approaches. The HIBOU 2030 method is thus design to place the urban system integrating the NBS and theirs alternatives at the core of its approach, with the objective of contributing to several of the action-oriented global targets for 2030 outlined in the Global Biodiversity Framework (GBF)[2] such as: Target 11 - Restore, Maintain and Enhance Nature’s Contributions to People, the Target 12 - Enhance Green Spaces and Urban Planning for Human Well-Being and Biodiversity and the Target 14 - Integrate Biodiversity in Decision-Making at Every Level. HIBOU 2030 is based on the hybridization of several area of expertise (e.g. Life Cycle Assessment, ecology, urban planning, etc.) and its fundamental principles are as follows: 1) interactions (both positive and negative ) between biodiversity, NBS and the urban project occur on the project site (in situ) but also on global scale (ex-situ) 2) the multifunctionality of NBS is one of the answers to numerous urban challenges and it must be taken into account in the analysis of the results; 3) the integrated approach necessitates the establishment of a shared semantics among the various fields of expertise; a common macro-model to characterize the system to be assessed and the different development options; the interdependence of results for each issue. Consequently, a parameter variation to address one of the questions will inherently influence the others.HIBOU 2030 method and its associated toolset facilitate the assessment the urban project’s contribution to the following urban challenges: 1) the climate change (1 indicator); 2) the biodiversity in situ and ex situ (8 indicators). These indicators are designed to address as much as possible of the five pressures on the biodiversity: global warming, land use change, pollution, overexploitation of resources, introduction of invasive species; 3) the stormwater management (1 indicator); 4) the urban heat island (UHI) mitigation (1 to 3 indicators); 5) the urban quality for the citizens, based on a qualitative assessment grid considering 24 criteria.HIBOU 2030 is a tool used to conduct expertise and research studies, thereby supporting various stakeholders’ analyses and decision-making processes concerning construction and renovation actions for buildings and urban projects. Continuous improvement is achieved through the collection and analysis of feedback from its use in various European contexts. [1]https://sciencebasedtargetsnetwork.org [2]https://www.cbd.int/gbf/target
Bonnes pratiques et mauvaises surprises de l'intelligence artificielle pour la gestion des connaissances tacites en entreprise
No full textNational audienceABSTRACT. The transmission of tacit knowledge represents a major challenge for many organizations. These same organizations are now experiencing the emergence of Artificial Intelligence and the various transformations it brings on many domains. All these transformations lead us to consider how AI could contribute to the transmission of tacit knowledge. This question was the subject of the "Connaissances Tacites" workshop held as part of the EGC 2025 conference. This article summarizes the discussions held during the workshop on the good practices and bad surprises of AI for knowledge management.La transmission de connaissances tacites représente un important défi pour des nombreuses organisations. Ces mêmes organisations sont aujourd'hui confrontées à l'émergence de l'Intelligence Artificielle et les différentes transformations qu'elle apporte. Ces transformations interrogent et nous amènent à nous intéresser à l'apport que l'IA pourrait avoir dans la transmission des connaissances tacites. Cette question a animé l'atelier "Connaissances Tacites" réalisé dans le cadre de la conférence EGC 2025. Cet article résume les nombreuses échanges réalisées pendant l'atelier autour des bonnes pratiques et mauvaises surprises de l'IA pour la gestion de connaissances.</div
Mechanical behavior of Glulam samples subjected to thermal and moisture gradients
No full textArticle soumis en cours de validation. Résumé sous la responsabilité de H. Daher.International audienceGlued laminated timber (Glulam) thanks to its sustainability and structural performance, is increasingly used in construction. However, during fire exposure, the structural integrity of buildings and the safety of occupants may be significantly compromised. One of the current challenges is to better understand the mechanical properties of non-carbonized wooden structural elements subjected to temperatures up to 200- 250°C.Research conducted at CSTB and the Navier laboratory aims to investigate the effects of temperature and moisture content on the mechanical properties of wood. This work presents tests considering thermal and moisture gradients within the wood samples. Additionally, the thermal recovery behavior after exposure to elevated temperatures is investigated to assess the structural performance of timber elements upon cooling. Moreover, the experiments were conducted on samples with three different dimensions (S1, S2 and S3) to evaluate the scale effects on compressive strength
Aerodynamics analysis of a cubical body with 1DoF rotational motion: Experimental and numerical investigations
No full textInternational audienc
Chlordecone in indoor dust and associated human exposure in the French West Indies
No full textChlordecone (CLD) is an organochlorine pesticide with various toxicities, widely used from 1972 to 1993 in the French West Indies lands (FWI, Guadeloupe and Martinique). It can remain in environment leading to indoor contamination by pollutants coming from outside. Therefore, investigating indoor pollutants is necessary due to the potential indoor dust ingestion though hand-to-mouth contact, in particular for children. No chemical analytical methods measure CLD in indoor dust and we propose to investigate its presence in this specific compartment, in Martinique. CLD was analyzed from dust samples taken from homes and schools (n=47). Pressure liquid extraction (PLE) with the most suitable mixture solvent of hexane and ethyl acetate (85:15) allowed to extract CLD from dust followed with gas chromatography coupled to tandem spectrometry (GC/MS/MS) analysis. A sampled mass of 25 mg optimal for analysis.. Concentrations of CLD in indoor dust varied from < 16 to 247 ng/g. Exposure to CLD through indoor dust ingestion was assessed too and does not exceed 1.5% and 0.1%, of the acceptable daily intake, in childrens and adults, respectively. However, this exploratory study was conducted on a very limited number of dust samples, not representative of the French West Indies population.</div
An empirical correlation for burning of spruce wood in cone calorimeter for different heat fluxes
No full textInternational audienceThis article proposes an empirical expression to describe the pyrolysis and charring of spruce wood in bench-scale experiments for a wide range of incident heat fluxes. Spruce wood samples were exposed to a cone radiant heater oriented vertically with varying intensities, ranging from q′′ cone = 22 to 93.5 kW m -2 over 53 test samples. The mass loss rate (MLR), the position of the char front and a preliminary additional heat source from smoldering or flaming combustion were experimentally determined. The experimental data were processed to express the burning rate as a function of heat flux and char front position. A grouping of the experimental curves was obtained, allowing to predict the MLR outcome over time regardless of the incident heat flux. A linear regression at the quasi-steady state regime allowed the determination of the fitting coefficients of the correlation, which ultimately correspond to the mass of volatiles produced per unit of energy input into the material. A comparison was made with theoretical analysis of the pyrolysis of charring materials from the literature, and the discrepancies with the proposed approach and its limitations were finally discussed. The main advantage of this approach is that it provides a generalized expression, requiring minimal input of material properties, which predicts the MLR change over time for any heat flux within engineering accuracy.</div