HAL-MINES ParisTech
Not a member yet
27348 research outputs found
Sort by
Characterization of the ionization response of argon to nuclear recoils at the keV scale with the ReD experiment
No full textInternational audienceIn the recent years, argon-based experiments looking for Dark Matter in the Universe have explored the non-standard scenario in which Dark Matter is made by low-mass Weakly Interacting Massive Particles, of mass in the range of 1-10 GeV instead of the canonical hundreds of GeV. Detecting such particles is challenging, as their expected signatures are nuclear recoils with energies below 10 keV, observable solely via ionization. This necessitates a precise understanding of the detector response in this energy regime, which remains incomplete for argon. To address this, the ReD experiment was developed within the framework of the DarkSide-20k Collaboration to produce and characterize few-keV nuclear recoils. A compact dual-phase argon Time Projection Chamber (TPC) was irradiated with neutrons from a Cf252 source, to produce Ar recoils in the energy range of interest via (n,n') elastic scattering. A downstream spectrometer composed of 18 plastic scintillators detected the neutrons scattered off Ar nuclei, enabling recoil energy reconstruction via two-body kinematics. The ionization yield Qy of argon, defined as the number of electrons produced per unit energy deposit, was measured in a model-independent way between 2 and 10 keV. These measurements extend direct experimental coverage well below the previous limit of approximately 7 keV. The results are consistent with existing data above 7 keV, while they indicate a higher Qy at lower energies
Insolubility as a goal: Joint U-I labs for sustaining paradoxes towards Pasteur-like research
No full textInternational audienceUniversity–industry collaborations (UICs) are increasingly promoted to foster innovation, yet existing research largely treats the tensions they generate as problems to be mitigated or resolved through alignment, proximity, or transfer-oriented governance. Drawing on paradox theory, this paper reconceptualizes UIC tensions as enduring paradoxes that must be actively sustained to support Pasteur-like, use-inspired research.We examine joint university–industry laboratories (JUILs) as organizational arrangements designed to maintain the simultaneous presence of academic and industrial logics. Based on a qualitative study of 13 JUILs supported by the French National Centre for Scientific Research (CNRS), drawing on 46 interviews and 117 secondary sources, we identify governance mechanisms that institutionalize the four interrelated paradoxes: belonging, performing, organizing, and learning; through dual academic–industrial leadership, shared but revisable research agendas, mutual proposal and veto rights, standardized intellectual property frameworks, bounded autonomy, or iterative steering processes aligned with doctoral research cycles.By mobilizing paradox theory in the context of UICs, the paper shifts attention from tension resolution toward the governance of insolubility, showing how JUILs operate as Pasteur-like research settings beyond technology-transfer logics while satisfying both academic and industrial stakeholders
From one-off collaboration to embedded practices: SMEs’ trajectories in university-industry collaborative research
No full textInternational audienceSmall and medium-sized enterprises (SMEs) remain weakly represented in university–industry collaborations (UIC), despite their importance for innovation and economic growth. Prior research mainly focuses on large firms or analyzes UIC at the level of individual projects, leaving the firm-level dynamics of SMEs’ sustained engagement in collaborative research underexplored. This study adopts an evolutionary perspective to examine how SMEs initiate, structure, and institutionalize collaborative research with universities.The study draws on a longitudinal multiple-case analysis of 21 French SMEs engaged in repeated UICs. Based on 32 semi-structured interviews and 83 secondary data sources, we reconstruct firms’ engagement trajectories across multiple collaborative research initiatives. Using an inductive process approach, we identify three interrelated phases: preconditions, in which organizational transitions, sectoral needs and CEO exposure to scientific networks shape latent research orientations; formalization, characterized by the adoption of standardized collaboration instruments and explicit research roles; and institutionalization/transformation, where collaborative research becomes embedded in organizational routines, exceeding initial expectations and occasionally becoming a component of the client relationship.By shifting the focus from individual projects to firm-level trajectories, this study contributes a process model of SMEs’ sustainable engagement in UIC and offers insights for managers and policymakers seeking to foster durable collaborative research strategies
Entretien avec Aurélien Portelli sur le fondateur de l’OPPBTP : « Pierre Caloni a permis la rationalisation de la prévention dans le BTP » (entretien réalisé par Isabelle Condou)
No full textAurélien Portelli est enseignant-chercheur à Mines Paris - PSL. Ses travaux portent sur l’histoire des risques et des crises dans l’industrie. Dans le cadre de ses recherches, il mène une étude sur l’apport de Pierre Caloni à la prévention des accidents du travail
Poster : Relations science-industries : stabilisation au service de la répétition du double impact
No full textInternational audienc
Vapor–Liquid Equilibrium of the Hydrogen Sulfide (H 2 S)–Propylene (C 3 H 6 ) Binary System: Experimental and Modeling Study
No full textInternational audienceThe study of the phase behavior of the binary system hydrogen sulfide (H2S)–propylene (C3H6) is necessary for the optimization of gas sweetening processes and petrochemical streams. This study presents new isothermal vapor–liquid equilibrium (VLE) measurements for this system at 278.21, 298.12, 323.06, and 348.13 K, at pressures up to 5.8 MPa. The data were obtained using a precise static-analytic method with two magnetic capillary samplers (ROLSI(R)) for phase analysis by gas chromatography. The measurement uncertainties are u(T)= 0.02 K for temperature, u(P)= 0.0009 MPa for pressure, and u(x,y) = 0.001 for molar compositions. To model this data, a ϕ–ϕ approach utilizing the translated consistent Peng–Robinson (tc-PR) equation of state was used. For the liquid phase, we compared the classical van der Waals mixing rules against the Wong-Sandler mixing rules coupled with the NRTL model. Subsequently, a multiparametric equation of state was utilized to extend the analysis. After optimizing the parameters of each model by fitting them to experimental data, the final models accurately describe the phase behavior of the system. Their reliability and suitability for industrial process design and simulation are thereby demonstrated
Soil carbon literature review in the humanities and the social sciences
No full textInternational audienceDespite rising interest in the humanities and social sciences, as attested in this book, soil carbon remains scarcely addressed in these fields. This literature review introduces three emerging sets of literature in social and human sciences that started addressing the knowledge, governance and practices related to soil carbon. We do not aim for comprehensiveness: instead, we would like to outline some major inspirations and orientations of recent research into soil carbon. We shall distinguish between: -Social studies of soil carbon sciences – i.e. a strand of research in history and sociology that focuses on the social practices of knowledge production on soil carbon within the scientific communities, and their reconfigurations in the context of the fight against climate change. -Social studies of soil carbon economy – i.e. a strand of research in political ecology and economic sociology that analyses the rising focus on soils as carbon sinks in climate governance and the associated development of soil carbon accounting schemes and metrics. -Social studies of soil regeneration – i.e. a set of writings in environmental humanities that addresses soil organic matter regeneration understandings and practices, such as composting, in a range of rural and urban contexts
All-sky search for continuous gravitational-wave signals from unknown neutron stars in binary systems in the first part of the fourth LIGO-Virgo-KAGRA observing run
No full textInternational audienceWe present the results of a blind all-sky search for continuous gravitational-wave signals from neutron stars in binary systems using data from the first part of the fourth observing run (O4a) using LIGO detectors data. Rapidly rotating, non-axisymmetric neutron stars are expected to emit continuous gravitational waves, whose detection would significantly improve our understanding of the galactic neutron star population and matter under extreme conditions, while also providing valuable tests of general relativity. Neutron stars in binary systems likely constitute a substantial fraction of the unobserved galactic population and, due to potential mass accretion, may emit stronger gravitational-wave signals than their isolated counterparts. This search targets signals from neutron stars with frequencies in the 100-350 Hz range, with orbital periods between 7 and 15 days and projected semi-major axes between 5 and 15 light-seconds. The analysis employs the GPU-accelerated fasttracks pipeline. No credible astrophysical signals were identified, and, in the absence of a detection, we report search sensitivity estimates on the population of neutron stars in binary systems in the Milky Way
Upper Limits on the Isotropic Gravitational-Wave Background from the first part of LIGO, Virgo, and KAGRA's fourth Observing Run
No full textInternational audienceWe present results from the search for an isotropic gravitational-wave background using Advanced LIGO and Advanced Virgo data from O1 through O4a, the first part of the fourth observing run. This background is the accumulated signal from unresolved sources throughout cosmic history and encodes information about the merger history of compact binaries throughout the Universe, as well as exotic physics and potentially primordial processes from the early cosmos. Our cross-correlation analysis reveals no statistically significant background signal, enabling us to constrain several theoretical scenarios. For compact binary coalescences which approximately follow a 2/3 power-law spectrum, we constrain the fractional energy density to (95% cred.), a factor of 1.7 improvement over previous results. Scale-invariant backgrounds are constrained to , representing a 2.1x sensitivity gain. We also place new limits on gravity theories predicting non-standard polarization modes and confirm that terrestrial magnetic noise sources remain below detection threshold. Combining these spectral limits with population models for GWTC-4, the latest gravitational-wave event catalog, we find our constraints remain above predicted merger backgrounds but are approaching detectability. The joint analysis combining the background limits shown here with the GWTC-4 catalog enables improved inference of the binary black hole merger rate evolution across cosmic time. Employing GWTC-4 inference results and standard modeling choices, we estimate that the total background arising from compact binary coalescences is at 90% confidence, where the largest contribution is due to binary black holes only,
Rethinking Metrics and Diffusion Architecture for 3D Point Cloud Generation
No full textInternational audienceAs 3D point clouds become a cornerstone of modern technology, the need for sophisticated generative models and reliable evaluation metrics has grown exponentially. In this work, we first expose that some commonly used metrics for evaluating generated point clouds, particularly those based on Chamfer Distance (CD), lack robustness against defects and fail to capture geometric fidelity and local shape consistency when used as quality indicators. We further show that introducing samples alignment prior to distance calculation and replacing CD with Density-Aware Chamfer Distance (DCD) are simple yet essential steps to ensure the consistency and robustness of point cloud generative model evaluation metrics. While existing metrics primarily focus on directly comparing 3D Euclidean coordinates, we present a novel metric, named Surface Normal Concordance (SNC), which approximates surface similarity by comparing estimated point normals. This new metric, when combined with traditional ones, provides a more comprehensive evaluation of the quality of generated samples. Finally, leveraging recent advancements in transformer-based models for point cloud analysis, such as serialized patch attention , we propose a new architecture for generating high-fidelity 3D structures, the Diffusion Point Transformer. We perform extensive experiments and comparisons on the ShapeNet dataset, showing that our model outperforms previous solutions, particularly in terms of quality of generated point clouds, achieving new state-of-the-art. Code available at https://github.com/matteo-bastico/DiffusionPointTransformer