HAL-MINES ParisTech
Not a member yet
27348 research outputs found
Sort by
Libérer la France du gaz fossile : c'est possible !
No full textEn 2024, le gaz méthane consommé en France était à 97 % d’origine fossile, importé pour plus de la moitié des États-Unis, de Russie et d’Algérie. En plus de constituer une vulnérabilité géopolitique pour l’Europe, le gaz fossile constitue aussi un poids climatique et économique avec près de 22 % des émissions nationales de gaz à effet de serre et environ la même proportion du déficit commercial entre 2021 et 2023.Face à ses enjeux, l'approche reposant sur un développement massif des gaz “verts” semble fragile. Seule la méthanisation est aujourd’hui opérationnelle au prix d’un surcoût important pour les finances publiques, et même dans les scénarios les plus optimistes, la rareté de la biomasse conduit irrémédiablement à une conclusion simple : il faut consommer moins de gaz.Cette réduction, pour être soutenable, doit être planifiée. Seuls les usages industriels critiques (chimie et flexibilité du réseau électrique notamment) semblent justifier un maintien à terme. Le chauffage résidentiel et tertiaire, en revanche, offre un levier majeur de réduction. Encore faut-il rendre cette transition économiquement viable et socialement acceptable, voire désirable : meilleure information des consommateurs, soutien ciblé aux alternatives et notamment aux pompes à chaleur, rééquilibrage fiscal entre électricité et gaz, et péréquation tarifaire pour protéger les plus vulnérables sont autant de leviers pour actionner cette transition.Mais transformer la consommation ne suffit pas : c’est l’ensemble du réseau qu’il faut adapter pour maintenir des coûts compétitifs pour les consommateurs restants. Endiguer les nouveaux raccordements et organiser la réduction de l’extension géographique du réseau sont des actions indispensables pour redéfinir la place gaz dans le système énergétique. Il s’agit aussi de construire une vision d’avenir pour la filière et remplacer l’espoir irréaliste des gaz “verts” pour tous, par une vision multi-énergie pragmatique qui pourrait se construire par un rapprochement entre les gestionnaires de réseau de distribution de gaz et d’électricité
Impact of the polydispersion of TiO materials on their particle size calculated from specific surface area results obtained during an interlaboratory comparison exercise
No full textInternational audienceIn this work, four samples of TiO2 powder materials with different structures (rutile, anatase), surface coatings and morphologies (rod, pseudo-spherical) were characterized by four partners involving complementary methods. With the aim of producing inter-laboratory reproducibility data, the specific surface-area, bulk density, and number size distribution were measured, yielding a satisfying agreement between partners. Second, the equivalent diameter of constituent particles was determined from the sample VSSA – accounting for polydispersion – and compared to electron microscopy (EM). Constituent particle diameters ranged from 15 to 225 nm according to EM analyses. The relative discrepancies between VSSA-based and EM-based diameters were within ±20%. Out of the four samples under study, TiO2-μ-rutile leads to a larger deviation, which was attributed to surface coating thanks to complementary analysis. Assuming that the sample is pure, an equivalent diameter based on the VSSA can be determined, provided that the shape of constituent particles is known or supposed
Structurer une fonction innovation comme levier de patrimonialisation face à la création destructrice : une étude de cas dans le luxe artisanal.
No full textInternational audienc
Swift-BAT GUANO follow-up of gravitational-wave triggers in the third LIGO-Virgo-KAGRA observing run
No full textInternational audienceWe present results from a search for X-ray/gamma-ray counterparts of gravitational-wave (GW) candidates from the third observing run (O3) of the LIGO-Virgo-KAGRA (LVK) network using the Swift Burst Alert Telescope (Swift-BAT). The search includes 636 GW candidates received in low latency, 86 of which have been confirmed by the offline analysis and included in the third cumulative Gravitational-Wave Transient Catalogs (GWTC-3). Targeted searches were carried out on the entire GW sample using the maximum--likelihood NITRATES pipeline on the BAT data made available via the GUANO infrastructure. We do not detect any significant electromagnetic emission that is temporally and spatially coincident with any of the GW candidates. We report flux upper limits in the 15-350 keV band as a function of sky position for all the catalog candidates. For GW candidates where the Swift-BAT false alarm rate is less than 10 Hz, we compute the GW--BAT joint false alarm rate. Finally, the derived Swift-BAT upper limits are used to infer constraints on the putative electromagnetic emission associated with binary black hole mergers
La transformation numérique de l’hôpital : comment collaborer avec les start-ups ?: Le cas de la mise en place d’une activité de télésurveillance comme mise en dispositif organisationnel
No full textEncouragées par les politiques de santé, les start-ups développent des outils numériques pour tenter de répondre aux besoins des hôpitaux. Les enjeux sont multiples en matière d’innovation, d’exploration du nouveau, ou d’apprentissage, aussi bien du côté des start-ups que des hôpitaux. Pourtant, peu de travaux analysent les actions conjointes des acteurs hospitaliers et des start-ups. En s’appuyant sur une étude de cas longitudinale, l’objectif de cet article est de retracer la construction d’une action collective distribuée entre des acteurs aux rôles complémentaires, visant à la fois à concevoir un outil numérique et à favoriser son appropriation et sa reconnaissance institutionnelle. Nous étudierons en particulier l’agencement progressif d’éléments de nature hétérogène conduisant à un processus de « mise en dispositif organisationnel ». Cette approche permet de mettre en évidence les interdépendances entre les processus d’institutionnalisation et d’appropriation ainsi que les apprentissages organisationnels relatifs aux collaborations entre start-ups et les acteurs hospitaliers
Activation of lysosomal iron triggers ferroptosis in cancer
No full textInternational audienceIron catalyses the oxidation of lipids in biological membranes and promotes a form of cell death called ferroptosis1. Defining where this chemistry occurs in the cell can inform the design of drugs capable of inducing or inhibiting ferroptosis in various disease-relevant settings. Genetic approaches have revealed suppressors of ferroptosis2-4; by contrast, small molecules can provide spatiotemporal control of the chemistry at work5. Here we show that the ferroptosis inhibitor liproxstatin-1 exerts cytoprotective effects by inactivating iron in lysosomes. We also show that the ferroptosis inducer RSL3 initiates membrane lipid oxidation in lysosomes. We designed a small-molecule activator of lysosomal iron-fentomycin-1-to induce the oxidative degradation of phospholipids and ultimately ferroptosis. Fentomycin-1 is able to kill iron-rich CD44high primary sarcoma and pancreatic ductal adenocarcinoma cells, which can promote metastasis and fuel drug tolerance. In such cells, iron regulates cell adaptation6,7 while conferring vulnerability to ferroptosis8,9. Sarcoma cells exposed to sublethal doses of fentomycin-1 acquire a ferroptosis-resistant cell state characterized by the downregulation of mesenchymal markers and the activation of a membrane-damage response. This phospholipid degrader can eradicate drug-tolerant persister cancer cells in vitro and reduces intranodal tumour growth in a mouse model of breast cancer metastasis. Together, these results show that control of iron reactivity confers therapeutic benefits, establish lysosomal iron as a druggable target and highlight the value of targeting cell states10
Federated Digital Twins Platform for Smart City Logistics: A Knowledge-Driven Approach
No full textInternational audienceUrban logistics faces increasing pressure from rising population densities, escalating delivery demands, and constrained urban resources. Traditional logistics systems struggle to adapt to real-time urban dynamics, leading to inefficiencies, congestion, and environmental concerns. A key challenge lies in mobilizing underutilized assets, such as off-hour freight parking, and adopting multimodal solutions to navigate diverse and increasingly strict regulations, thereby enhancing both sustainability and operational efficiency. However, effective management and utilization of these assets require real-time visibility, cross-stakeholder collaboration, and intelligent decision-making. This study proposes a federated digital twin platform to enhance logistics operations efficiency by integrating asset management and knowledge-driven operations management, relying on real-time asset visibility and delivery knowledge, such as destination characteristics and preferred logistics modalities. Unlike traditional logistics planning, which relies on static assumptions, our approach adapts to urban constraints by continuously querying real-time asset information and integrating logistics-related knowledge into operations management. To assess the effectiveness of this approach, an optimization-based simulation framework with decision-making tools is developed. The study evaluates multi-echelon logistics networks, incorporating micro-hubs, dynamic transshipment points, and multimodal logistics options, including on-foot porters, E-cargo bikes, and Road Autonomous Delivery Robots (RADRs). Findings demonstrate that integrating federated digital twins with knowledge-driven approaches, such as destination-based clustering and modality selection, reduces costs by over 50% and emissions by more than 30%. This study underscores the transformative potential of digital twins in enabling real-time, knowledge-driven operations management, and fostering more sustainable and efficient urban logistics systems
The impact of scientific controversies on standards and methodologies in the voluntary blue carbon market
No full textInternational audienceWith the proliferation of scientific studies on blue carbon in recent years, numerous controversies have emerged in the academic literature. Simultaneously, the voluntary carbon market has expanded significantly, initially at the terrestrial level and, over the past decade, also in the marine realm. While some studies have the emergence of a specialized literature on the blue carbon market, none have examined the connections and relationships between scientists and the voluntary carbon market (VCM). This article maps the scientific controversies surrounding the methodologies developed by standards for the blue carbon market in order to clarify how these controversies are considered in the methodology update process. A quantitative analysis of articles highlighting controversies was conducted, accompanied by a qualitative analysis of methodologies used in the VCM. Interviews with key stakeholders further provided depth to the analysis. An acceleration in updates to certification methodologies developed by standards is observed, correlated with the increasing number of articles highlighting controversies. However, the relationship between research and certification methodologies appears challenging as few scientific articles are cited in most methods, and reciprocally. Mapping the actors reveals that the links and interactions are diverse and occur through various communication channels
A Comparative Study of Optimization Approaches for Battery EMS in Commercial Buildings
No full textInternational audienc
Beyond Ownership As Usual: The Implications of Steward-Ownership For Management Research
No full textInternational audienceSteward-ownership is a novel conceptualization of ownership galvanizing attention from entrepreneurs, business owners, policymakers, and academics around the world. Two main principles distinguish it from traditional models of ownership: (1) decoupling control rights and economic rights and (2) asset lock, whereby company resources cannot be privatized by shareholders. This curated conversation among 11 interdisciplinary researchers unpacks the transformative potential of steward-ownership for management theory. Contributors discuss how our current knowledge of steward-ownership, along with what we can come to know through targeted future research, offers important insights for scholarship on purpose, entrepreneurship, corporate governance, impact investing, hybridity, and alternative forms of organizing