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Muon tracking in a LiquidO opaque scintillator detector
No full textInternational audienceLiquidO is an innovative radiation detector concept. The core idea is to exploit stochastic light confinement in a highly scattering medium to self-segment the detector volume. In this paper, we demonstrate event-by-event muon tracking in a LiquidO opaque scintillator detector prototype. The detector consists of a 30 mm cubic scintillator volume instrumented with 64 wavelength-shifting fibres arranged in an 88 grid with a 3.2 mm pitch and read out by silicon photomultipliers. A wax-based opaque scintillator with a scattering length of approximately 0.5 mm is used. The tracking performance of this LiquidO detector is characterised with cosmic-ray muons and the position resolution is demonstrated to be 450 m per row of fibres. These results highlight the potential of LiquidO opaque scintillator detectors to achieve fine spatial resolution, enabling precise particle tracking and imaging
Exact separable solutions of two-dimensional time-fractional nonlinear biological population model under the regularized Prabhakar and ψ-Hilfer fractional-order derivatives
No full textInternational audienceThe main aim of this work is to investigate how to compute the exact separable solutions using the invariant subspace method for the fractional-order time derivative of two-dimensional nonlinear partial differential equations involving two space and one-time variables under two different fractional-order derivative definitions, namely the regularized Prabhakar and -Hilfer fractional-order derivatives. We also explicitly demonstrate the importance and usefulness of the method of the invariant subspace approach in computing the exact separable solutions for the two-dimensional fractional-order time derivative of the biological population model, which helps more accurately predict how populations will grow or shrink. More specifically, we show systematically how to compute the linear spaces for the above-mentioned model with the help of the invariant subspace approach. Furthermore, the computations of exact separable solutions are investigated for the linear and nonlinear biological population models under the above-mentioned two different time fractional-order derivatives with the help of the computed invariant linear spaces. Additionally, we notice that the computed solutions of the considered equations under the -Hilfer fractional derivative are valid under the -Riemann–Liouville, -Caputo, Hilfer, Katugampola, Caputo–Katugampola, Riemann–Liouville, and Caputo fractional derivatives because the -Hilfer fractional derivative is a generalization of those fractional derivatives. Also, note that the computed exact separable solutions to the underlying equation under two fractional-order derivatives are expressed in terms of trigonometric, exponential, and polynomial functions with two or three parameters of Mittag-Leffler functions. In addition, the obtained solutions under different fractional-order derivatives are compared with two-dimensional (2D) graphical representations. Finally, the exact separable solutions are presented for the initial and boundary value problems (IBVPs) of the discussed model under various fractional-order derivatives and their comparison
Environmental impacts of supercritical fluids processes: A critical review of life cycle assessment studies
No full textInternational audienceThe application of supercritical fluids (SCF) in industrial and research processes has gained attention in recent years for their unique properties and potential environmental benefits. Frequently described as "green solvents", SCF can reduce of replace the use of conventional organic solvents. However, broader adoption requires a clear understanding of their full life cycle environmental impacts. Life cycle assessment (LCA) has been widely used to evaluate the environmental performance of SCF technologies.This study critically reviews 70 LCA studies of SCF processes across various applications through the four phases of LCA: goal and scope definition, life cycle inventory, life cycle impact assessment, and interpretation to identify methodological gaps and trends in energy use, solvent consumption, and environmental impacts. Despite variability in modelling approaches, process-level trends emerge: for gasification, global warming results range from -0.2 to 5 kg CO2eq.kg; for extraction from 0.2 to 153 kg CO2eq.kg depending on feed and scale. Contribution analyses highlight that energy is the main hotspot, especially in supercritical water gasification and transesterification, even though yielding higher-quality output and lower solvent consumption. Benchmarking results are mixed: 27 studies reporting lower environmental impacts for SCF processes, while 18 studies report higher impacts, especially in extraction applications. Sensitivity analyses highlight the influence of electricity mix, feed concentration, and solvent recycling on LCA outcomes. This review provides targeted recommendations to enhance consistency and accuracy in future LCA studies. By synthesizing current findings, it supports the development of more sustainable SCF technologies from early stage to support their broader adoption
Simulation of shockless spalling fragmentation using the Discrete Element Method (DEM)
No full textInternational audienceIn the present study a Discrete Element Method (DEM) is considered to model the dynamic behaviour and fragmentation mechanisms of alumina ceramic under high strain-rate shockless loading. GEPI (high-pulsed power) spalling experiments are simulated. The DEM allows to take into account the accurate propagation and interaction of stress waves within the samples upon calibration of microscopic bond parameters. The results indicate that a standard failure criterion can effectively represent the spalling phenomenon, though discrepancies with experimental data increase at higher strain rates. To address this, the study combines the DEM approach with a damage law, specifically the first and second order Kachanov damage law, tomodel crack initiation and propagation. Comparative analysis with experimental rear face velocity profiles validates the approach. The strain-rate sensitivity of the present DEM model is explored using loading pulses of increasing intensity that induce different strain-rate levels. This research demonstrates that the DEM approach can effectively model dynamic behaviour in brittle solids leading to a multiple fragmentation sensitive to the strain rate
The High Voltage Splitter board for the JUNO SPMT system
No full textInternational audienceThe Jiangmen Underground Neutrino Observatory (JUNO) in southern China is designed to study neutrinos from nuclear reactors and natural sources to address fundamental questions in neutrino physics. Achieving its goals requires continuous operation over a 20-year period. The small photomultiplier tube (small PMT or SPMT) system is a subsystem within the experiment composed of 25600 3-inch PMTs and their associated readout electronics. The High Voltage Splitter (HVS) is the first board on the readout chain of the SPMT system and services the PMTs by providing high voltage for biasing and by decoupling the generated physics signal from the high-voltage bias for readout, which is then fed to the front-end board. The necessity to handle high voltage, manage a large channel count, and operate stably for 20 years imposes significant constraints on the physical design of the HVS. This paper serves as a comprehensive documentation of the HVS board: its role in the SPMT readout system, the challenges in its design, performance and reliability metrics, and the methods employed for production and quality control
Expertise génétique de droit à la demande du ministère public : ordre public vs paix des familles
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On the convergence of Monte Carlo -generalized Polynomial Chaos for uncertainty propagation in k eff computations for neutronics
No full textInternational audienceThis paper addresses the analysis of power iteration methods applied to eigenvalue problems involving uncertainty. While several uncertain power iteration procedures have been proposed in the literature and have demonstrated empirical convergence, a rigorous theoretical justification of their convergence properties remains lacking. The objective of this work is to investigate the convergence behavior of such methods in a stochastic or parametric uncertainty setting. The proposed framework focuses on the propagation of uncertainty through the MC-gPC [1, 2] power iteration process and on the characterization of the resulting random eigenvalues and eigenfunctions. By combining spectral analysis with probabilistic tools, the study establishes conditions under which convergence can be guaranteed
Photovoltaic energy forecast; influence of two numerical weather forecast datasets on the performance of an analytical and three machine learning models
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In vitro comparison of biological properties of CoCr, Ti-6Al-4V, and PEEK for removable partial denture
No full textInternational audienceAbstractStatement of problem : To address the limited biocompatibility of conventional removable dental prostheses (RDPs), new materials and manufacturing techniques are being actively investigated.Purpose : This in vitro study aimed to evaluate and compare the biological response of human fibroblast (HGF) to cobalt-chrome (Co-Cr), titanium alloy (Ti), and polyetheretherketone (PEEK), fabricated via tree distinct methods: casting, selective laser melting (SLM) and machining.Material and methods: The surface chemical composition and the wettability of cast Co-Cr, SLM Co-Cr, SLM Ti, machined Ti, and PEEK were assessed. HGF were cultured in contact with material extracts, and all assays were conducted following this exposure. Ion release was assessed using inductively coupled plasma atomic emission spectroscopy (ICP-AES), and pH measurement. Surface roughness was subsequently measured on each sample. Cell viability was assessed using the Live/Dead staining, while metabolic activity was evaluated using the Alamar Blue assay. Cell morphology was observed by scanning electron microscopy (SEM) and confocal microscopy, while inflammatory profile was assessed using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using one-way ANOVA and Tukey’s test (p < 0.05 and 0.001).Results: SLM Co-Cr exhibited higher Co and Cr surface content than cast Co-Cr, while SLM Ti showed a reduced titanium content and increased aluminum content relative to machined Ti. Among all tested materials, machined Ti demonstrated the highest surface wettability, evidenced by a significantly lower contact angle (p < 0.001). HGF exposed to extracts of machined Ti and PEEK exhibited greater cell viability and metabolic activity, comparable to the control group. In contrast, cast Co-Cr was associated with significantly increased IL-6 secretion, although TNF-α and IL-10 levels remained stable across tested groups.Conclusions: Machined titanium (Ti) and PEEK exhibited favorable in vitro biocompatibility, with high cell viability, enhanced cellular adhesion, and no significant cytotoxicity under our experimental conditions. These findings suggest that both materials may represent promising alternatives to CoCr alloys for the fabrication of removable partial dentures, although their clinical application requires further validation of their mechanical, physical, and long-term properties
Salinity Transition in the Ostia Lagoon During the Roman Period: Assessing the Feasibility of Salt Exploitation
No full textInternational audienceThis study examines long‐term salinity changes in the Ostia Lagoon between the 4th century cal BC and the 6th century cal AD , with emphasis on their implications for ancient salt production. Although Ostia's foundation is closely linked to the control of salt resources in the Tiber Delta, direct archaeological evidence of Roman‐period saltworks is scarce. To address this gap, this study combines micropalaeontological analysis of ostracod assemblages with a morphometric study of sieve pore features in Cyprideis torosa (Jones, 1850). This approach enables reconstruction of short‐term palaeosalinity dynamics. Core LOA–1 documents a transition from peatland to euryhaline lagoon between the 8th–6th and the 4th–3rd centuries cal BC , followed by repeated high‐salinity episodes. A notable peak coincides with the establishment of the Roman Castrum, suggesting favourable conditions for salt concentration. After the mid‐4th century cal BC , salinity peaks decreased, possibly reducing the lagoon's potential for saltworks and fostering greater reliance on the Maccarese saltworks. In the northern lagoon sector, hyperhaline conditions during the Roman period remain uncertain because of chronological gaps and the lack of sieve pore analysis. Overall, the results demonstrate both the potential and limitations of ostracod analysis as a palaeosalinity proxy and refine understanding of salt exploitation in the Tiber Delta. This study provides valuable insights into the long‐term socio‐environmental dynamics of the Mediterranean coastal wetlands, contributing to the advancement of geoarchaeological research on ancient salt production through salterns and its influence on human settlement patterns and economic practices