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Assessment of diesel exhaust emissions mitigation under variable meteorological conditions on AWG condensate quality for drinking water production
No full textInternational audienceWhile Atmospheric Water Generators (AWG) contribute to addressing the global issue of drinking water scarcity, they raise concerns regarding water contamination stemming from air pollution. This work aims to assess such risks and drinking water production capabilities through real-scale experimentations. An AWG from Kumulus was installed in Sense City scale 1 urban model (https://sense-city.ifsttar.fr/) near a diesel generator exhaust, with variations of temperature and relative humidity (RH). 14 untreated and treated condensate samples collected over 5 days were analyzed (ions, elements, organics); environmental gases (NO2, NO, CO2, CO, O3, TVOCs) and particulate matter were monitored in real-time. The main inorganic species found in the untreated condensate were nitrate, sulfate, ammonium, copper and aluminum (>0.5 mg/L). Among organics, BTX, naphthalene, phenanthrene and pyrene were found at significant concentrations (>1.5 µg/L). Only Al, Cu, pH, ammonium, and benzene exceeded EU regulation limits in untreated condensate, while the treated water fully complied. Air quality greatly affected condensate composition; strong correlation coefficients were found between aerosols and various inorganic compound concentrations (nitrates, Al), TVOCs appeared to be strongly correlated with aqueous benzene and naphthalene. Meteorological conditions were found to have a significant impact with dilution effect up to 2 – 10 times. Also, as suggested by Henry’s law, benzene air-to-water transfer was observed to be strongly and negatively correlated with ambient temperature. Overall, these results show AWGs’ great potential to produce compliant drinking water even in a highly polluted environment, though experimental environments should be expanded to different air pollution profiles and meteorological conditions
Economists, Economic Knowledge, and Central Banks
No full textInternational audienceWhat do economists do in central banks? Why do central banks hire economists? This book investigates the evolving role of economists and economic knowledge within central banks, arguing that their current centrality is neither self-evident nor historically inevitable. While the presence and influence of economists in central banks today may seem natural, this book shows that it is the result of a complex, gradual, and uneven historical process shaped by institutional structures, disciplinary transformations, and shifting relationships between science and policy. Drawing on a rich but dispersed body of literature, the book traces how economists progressively gained authority through the establishment of statistics departments, the adoption of macroeconometric models, and the emergence of a shared cognitive infrastructure between academia and central banks. Rather than focusing on individuals or doctrines, it examines general trends and institutional shifts across a series of national case studies to show how central banks function as boundary organizations, at the intersection of policy and science
Projet URBAN SQUAD, penser l’aménagement de la ville avec des collégiens. Enjeux pédagogiques et de médiations pour redessiner les alentours de la future Gare du Blanc-Mesnil de la ligne 16
No full textInternational audienceCette communication vise à questionner l’usage des outils de médiation dans les projets urbains, en s’appuyant sur le programme URBAN SQUAD, porté par l’association F93 dans le cadre du dispositif « la Culture et l’Art au Collège » du Conseil Départemental de la Seine-Saint-Denis, dont l’objectif est d’initier les collégiens à l’aménagement du territoire. Durant l’année 2023, nous sommes intervenues une quarantaine d’heures dans une classe de 4ème d’un collège du Blanc-Mesnil pour mettre en place un projet pédagogique dont l’objectif était de repenser un projet d’aménagement des espaces publics autour de la future du Gare du Blanc-Mesnil qui accueillera la nouvelle ligne 16 du métro. À cette occasion, nous avons pu constater que la question de la médiation dans ce projet fut prégnante, amenant à une double lecture de ses enjeux.Tout d’abord, il y a la médiation au niveau pédagogique, puisqu’il s’agissait de trouver une manière d’adapter nos discours et nos méthodes à un public jeune (avec des classes ULIS - unités localisées pour l'inclusion scolaire) dont la connaissance de leur territoire était localisée avec des espaces vécus relevant de l’affect (connaissance proche) et de la fonction (collège et activités extra-scolaires). Ensuite, cette expérience pédagogique a également permis de questionner la médiation du projet urbain en lui-même. Bien évidemment ces deux médiations se télescopaient par moment amenant à une réflexion plus large sur les modalités des médiations dans le cadre d’un développement d’un projet urbain. Tout l’enjeu de cette communication est, dans un premier temps de situer cette recherche dans un état de la littérature plus général, notamment lorsque l’on a à faire à un jeune public. Dans un second temps, nous reviendrons sur l’initiative Urban Squad pour en préciser la finalité pédagogique, ainsi que la méthodologie employée. Ces éléments nous permettront enfin d’ouvrir le débat sur la manière dont cette expérience reconfigure les perceptions des jeunes sur un espace en cours d’aménagement, au prisme de deux types de médiations ; la médiation pédagogique et la médiation autour d’un projet d’aménagement urbain
Mechanical and durability performance of metakaolin and fly ash-based geopolymers compared to cement systems
No full textInternational audienceThe environmental impact of Ordinary Portland Cement production, particularly its significant contribution to global CO2 emissions, has prompted the search for sustainable alternatives. This study investigates the durability and mechanical performance of metakaolin and fly ash-based geopolymer formulations compared to cement-based systems (CEM I and CEM III) under aggressive environmental conditions, without the use of heat curing. Among the six binder types tested, metakaolin-based MK II achieved a compressive strength of 33 MPa at 90 days—comparable to CEM III (35.2 MPa)—and the lowest water absorption (3.4 %). MK II also exhibited the highest durability, with superior resistance to carbonation, sulfate, and acid attacks, as well as minimal ultrasonic pulse velocity loss in the boiling test. Cement-based samples, particularly CEM I, displayed the best freeze-thaw resistance and lowest porosity increase after 150 cycles. Fire resistance testing classified MK I, MK II, and CEM III as A1-rated non-combustible materials. These results highlight the potential of metakaolin geopolymers—especially MK II—as sustainable, durable alternatives to cement, capable of performing in aggressive environments without additional energy input
Détection automatique des essieux relevés des poids lourds à partir d’images grâce aux réseaux de neurones convolutifs
No full textInternational audienceThe identification and classification of vehicles play a crucial role in various aspects of the control-sanction system. Current technologies such as weigh-in-motion (WIM) systems can classify most vehicle categories but they struggle to accurately classify vehicles with lifted axles. Moreover, very few commercial and technical methods exist for detecting lifted axles. In this paper, as part of the European project SETO (Smart Enforcement of TransportOperations), a method based on a convolutional neural network (CNN), namely YOLOv8s, was proposed for the detection of lifted truck axles in images of trucks captured by cameras placed perpendicular to the direction of traffic. The performance of the proposed method was assessed and it was found that it had a precision of 87%, a recall of 91.7%, and an inference time of 1.4 ms, which makes it well-suited for real time implantations. These results suggestthat further improvements could be made, potentially by increasing the size of the datasets and/or by using various image augmentation methods
Functional positioning in robotic patello-femoral arthroplasty: a step-by-step technique
No full textInternational audiencePatello-femoral arthroplasty (PFA) is an effective treatment option for isolated patello-femoral osteoarthritis. However, challenges remain regarding implant positioning and patellar tracking. Recent advances in implant design and robotic-assisted techniques have contributed to more personalized and reproducible procedures. Functional positioning (FP), a three-dimensional alignment concept, introduces a customized approach to optimize trochlear resurfacing and restore joint kinematics of the anterior compartment. This article presents a step-by-step surgical technique for PFA using FP principles in combination with an image-based robotic system. The technique ensures accurate preoperative planning, real-time intraoperative adjustments, and precise component placement. The key steps of this surgical technique include trochlear resurfacing assisted by an image-based robotic system and the restoration of patellar tracking, following a step-by-step approach that is both effective and reproducible. The use of FP enables personalized anterior compartment restoration, avoiding overstuffing and improving patellar tracking. Future studies will help refine FP strategies and further optimize outcomes in these patients
Villes du quart d'heure au-delà des métropoles : visualiser l'accessibilité des services dans les communes françaises (Poster)
No full textInternational audienceLe concept de la ville du quart d’heure gagnant à la fois en popularité et étant décrié par certains mouvements complotistes, il est nécessaire de remettre le modèle en perspective par une approche scientifique. Son applicabilité aux villes petites et moyennes et sa capacité à prendre en compte la diversité de la population et son effet sur l’accessibilité sont notamment remises en question. Le Système d’Information pour la Ville Durable et le Bâtiment Innovant (SIVDBI) développe donc un outil d’analyse d’accessibilité adapté aux villes petites et moyennes de la France hexagonale.Cette application web mobilise des données ouvertes pour calculer des temps de trajet aux services d’éducation, de santé et aux commerces en tout point d’une commune, combinés à des données de population pour construire des indicateurs d’accessibilité prenant en compte la densité. Les résultats sont affichés sous la forme de cartes interactives permettant d’identifier rapidement des quartiers manquant localement de services, ou à l’inverse des zones propices à la densification urbaine, profitant d’une très bonne offre de services par rapport à leur nombre d’habitants
Analyzing Ro-Ro short sea shipping connectivity in Spain: supply instability and policy implications
No full textInternational audienceIn the last decades, Roll-on/Roll-off (Ro-Ro) short-sea-shipping (SSS) services have emerged as key alternative to road transport for achieving a shift in the intra-European Union modal pattern. Indeed, European and national policymakers opted for Ro-Ro as a promising means for removing trucks from the roads by designing various policy instruments. In this regard, it is deemed essential for shippers having a regular Ro-Ro SSS supply that matches their demand requirements. Thus, monitoring such Ro-Ro connectivity along time is crucial to identify patterns and assess the effectiveness of policies implemented. However, several studies have attempted to quantify maritime transport connectivity through synthetic indexes, but few have explored connectivity for Ro-Ro cargo. For this reason, this study explores the situation of Ro-Ro by examining connectivity changes at Spanish ports over a decade (2009–2019) using the existing Foreland Port Connectivity Index (FPCI). The results indicate the port of Valencia appears as the most connected port and the port Barcelona stands out as the most evolving. The regional analysis distinguishing between the two Spanish maritime fronts offers further insights and suggest uneven effectiveness of policy measures depending on the regional and local contexts of ports
Signs of forest-ability: a semio-pragmatist account of creative approaches to sustainability
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Socio-technical lock-in as alignment process: tracing the joint development of pesticide dependency and vegetable production in Senegal (1900–2024)
No full textInternational audienceLock-in mechanisms are common explanations for the persistence of undesirable system configurations in the present. However, studies often analyse lock-ins statically, without tracing and explaining underlying processes. In this article, we explore the development of lock-in over time, by analysing the case study of pesticide lock-in the Senegalese vegetable sector. To this end, we draw on extensive archival document analysis. We trace pesticide lock-in through four periods (from the 1900s to 2024) and explain it as the result of alignment processes across multiple heterogenous dimensions: agricultural policy, input supply, scientific and technical knowledge, on-farm production, and vegetable commercialisation & consumption. These dimensions have aligned in stages, fuelling a dynamic of growing dependence on chemical control. To date, this overall alignment has only been partially challenged, stimulating several adaptations, reinforcing the chemical intensification process, and marginalising attempts to reduce pesticide use. The paper ends with a discussion of conformities and deviations in a case study from the existing literature on lock-in within the agri-food sector in the Global South, before suggesting ways out of the current pesticide lock-in