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Pour une science de la transition énergétique au service de la société. Rapport d’un groupe de travail interdisciplinaire de la cellule énergie du CNRS
No full textLa recherche sur la transition énergétique pose plusieurs défis de taille : c’est une recherche orientée problème (celui de la décarbonation du mix énergétique), qui doit être résolument éthique et intégrer dès sa formulation des principes de justice sociale et environnementale…, et ce alors même que la notion de transition est problématique en cela qu’elle donne l’impression que le processus qui mènera aux changements attendus – si changements il y a – sera linéaire et fondé sur la substitution d’une source d’énergie par une autre. Partant de ce constat, ce texte dresse des pistes de recherche sur des thématiques saillantes, notamment sur les acteurs et échelles des transitions, les techniques et leurs externalités, les modèles économiques et sociaux qui permettent de guider l’action, les modèles de consommation et de production, et il s’interroge sur les rapports entre consommation et production. Il défend in fine l’idée que la recherche, forcément interdisciplinaire et réflexive, a un rôle fort à jouer pour fonder l’action en matière de transition sur des constats scientifiquement fondés
Relativistic Electron and Proton Experiment for the HENON mission: simulated performance
No full textHEliospheric pioNeer for sOlar and interplanetary threats defeNce (HENON) is a 12U CubeSat that will explore for the first time ever the Distant Retrograde Orbit in the Sun-Earth system, bringing a payload suited for Space Weather observations and science. Initially designed for the Foresail-2 nanosatellite mission, the Relativistic Electron and Proton Experiment (REPE) instrument has since evolved for deployment in a variety of future missions, including the HENON mission. REPE is a particle telescope developed to measure fluxes of high-energy electrons and protons over broad ranges of energies, relevant to the space radiation environment. The instrument is designed to measure electron energy spectrum from 0.1 to 10.4 MeV and proton energy spectrum from 2 to hundreds of MeV. We present Monte Carlo simulations of REPE performance using Geant4. We evaluate the performance in terms of sensitivity (geometric factor), energy resolution, and cross-contamination between measured species. We show that the instrument meets the scientific requirements of the mission
Design of a distributed negative-pressure adsorption robot for energy-efficient closed-loop cleaning based on FSI and multi-physics optimization
No full textTo address the critical need for efficient and safe maintenance of high-rise glass curtain walls, this study presents an energy-efficient closed-loop cleaning system for distributed negative-pressure adsorption robots. The design integrates a 4 × 6 cm distributed suction array (total area 113.2 cm2) and a triangular polyurethane scraper (modified with 5% nano-silica), and is validated through fluid-structure interaction (FSI) analysis. Based on the dynamic equilibrium framework of modular robots, a novel 3D mechanical model with a yaw angle (θ = 15) reveals that the distributed adsorption can reduce the theoretical extreme adsorption force from 83.3 N to an engineering-feasible 29.4 N, with a reduction of 66.1% in required negative pressure (from 7370 Pa to 2500 Pa) and energy consumption. The multi-physics coupling analysis (fluid dynamics and solid mechanics) demonstrates that: ① Through optimized droplet atomization (Lechler nozzle, 45 ± 5 μm) and biomimetic scraper, the waste liquid recovery efficiency is 86.7%; ② The lightweight centrifugal impeller design driven by FSI reduces the weight by 40% and reduces the stress from 84.37 MPa to 68.5 MPa; ③ 120% flow redundancy (3.52 mL/min recycling and 2.93 mL/min supply) is addressed. This work bridges the gap between theoretical adsorption requirements and practical implementation, providing a standardized energy-saving solution for high-altitude cleaning robots
First-principles study on the synergistic regulation of magnetic and photocatalytic properties of ZnS by intrinsic point defects (V
No full textIn this study, F/Cu/VZn/Hi multi-defect coupled ZnS systems were innovatively constructed, and the regulatory mechanisms of their structure, magnetism, conductivity type, and photocatalytic CO2 reduction performance were systematically investigated. Structural stability of the systems is significantly enhanced by the synergistic introduction of F/Cu/Hi (formation energy as low as − 4.376 eV). Magnetism of the systems originates from unpaired spin electrons in the Cu2-3d9 orbital, with a magnetic moment contribution of 1 μB. A regular transition of magnetic moment spin distribution from localized states (Cu2+-S2−) to delocalized states (Zn-4s) is observed with increasing F− concentration. Different conductivity types can be achieved via precise regulation of F− concentration (n-type at 4.23% F−, p-type at 1.41%/2.82% F−). The optimized n-type system exhibits a narrow band gap (1.78 eV), broad spectral response (strong absorption in visible-infrared region), low electronic effective mass (0.20 m0), and high average hole-electron effective mass ratio ( = 3.54). Its conduction band minimum energy level is precisely matched with the potential for CO2 reduction to CH4, and CO2 adsorption/activation efficiency is significantly enhanced by the short-range synergistic effect between VZn and F−. ZnS-based functional materials with tunable magnetism, controllable conductivity type, and high-efficiency photocatalytic performance are successfully constructed, providing new insights and experimental support for the design of high-performance materials for spintronic devices and photocatalytic CO2 reduction cells
Prediction of electronic structure and magnetic properties of (Co, Cr, Fe, Mn, Ti, V) co-adsorbed monolayer MoSi
No full textThe geometrical structure, electronic properties, and magnetic properties of the materials with different transition metal atoms (Co, Fe, Mn, Cr, Ti and V) co-adsorbed on a monolayer MoSi2P4 substrate have been calculated based on first principles. The density of states of the transition metal co-adsorption system has a clear peak at the Fermi level, indicating the origin of magnetism. All adsorption systems are n-type doped, and charge transfer mainly occurs between TM and adjacent Si and Mo atoms. The Fe(Mo)Mn(Mo) adsorption system has the smallest magnetic moment, which is 5.150 μB, while the V(Si)Ti(Si) adsorption system has the largest magnetic moment, which is 8.56 μB. Fe(Mo)Fe(Mo) and V(Si)Ti(Si) of TM atom adsorption system show positive magnetic anisotropy and in-plane magnetic anisotropy. For other adsorption systems, MAE value is negative, showing vertical magnetic anisotropy. Our studies suggest that the application of Fe and Mn double transition metal atoms to monolayer MoSi2P4 may have potential in spintronics
The HST-Hyperion survey: Environmental imprints on the stellar mass function at z∼ 2.5
No full textNot all galaxies at cosmic noon (2 łesssim z łesssim 3) evolve in the same way. Particularly, it remains unclear how and to what extent the local environment -- especially the extreme overdensities of protoclusters -- affects the stellar mass assembly of its constituent galaxies at high redshifts. The imprint of these early processes is encoded in the galaxy stellar-mass function (SMF); comparing SMFs across environments therefore reveals differences in evolutionary history.
We present the SMF of the Hyperion proto-supercluster at z∼ 2.5, one of the largest and most massive protostructures in the early universe. This dataset yields the most statistically robust SMF of a single protostructure at z≳ 2. By comparing the SMF of the overdense peaks within Hyperion to the coeval field, we begin to answer the question of how early, and how strongly, a dense environment tilts the balance in favor of massive galaxies
Given that Hyperion resides in the field of the Cosmic Evolution Survey (COSMOS), we combined the extensive COSMOS2020 photometric catalog with ground-based spectroscopy and new grism spectroscopy from the Hubble Space Telescope ( ). The structure of Hyperion is defined based on a three-dimensional overdensity map, allowing us to place galaxies into (i) the highly overdense HST peaks of Hyperion, (ii) the less-overdense outskirts of Hyperion, or (iii) a coeval field. We performed 100 Monte Carlo realizations of the data to propagate redshift and stellar mass uncertainties, refitting galaxy properties in each realization. After constructing SMFs for the outskirts and peaks of Hyperion, we normalized them to that of the field to highlight differences in the underlying shape of the SMFs.
The overdense peaks of Hyperion host a striking excess of massive galaxies relative to the field: the number densities of log_ 10 (M_*/M_⊙)∼ 11 galaxies are ∼ 10 (M_*/M_⊙)∼ 9.5 galaxies are enhanced by only ∼ 3.5 higher than the coeval field, whereas log_ 10 On the other hand, both the SMF of the outskirts of Hyperion and the SMF of Hyperion as a whole mirror the overall shape of the coeval field.
Environmental effects that govern stellar mass growth are already well established by z∼ 2.5. The densest regions of Hyperion host galaxies that have already experienced accelerated stellar mass growth. Furthermore, this impact is largely masked in the total SMF of Hyperion, highlighting the necessity of deep spectroscopic surveys when uncovering environmental trends at high redshifts. These findings imply that high-redshift protostructures begin sculpting the high-mass end of the SMF well before the epoch when local clusters experience widespread quenching, and may provide the appropriate laboratories for producing the elevated star formation observed at cosmic noon
Improving the Antioxidant Profile of Yoghurt Using Red Seaweed
No full textThis study investigated the potential of Gracilaria sp. as a functional ingredient for yoghurt, focusing on its impact on consumer acceptance and its antioxidant capacity. The research employed a Completely Randomized Design (CRD) with three concentrations of added Gracilaria sp. ( 10%, 20%, and 30%). Key parameters analysed included pH, viscosity, total lactic acid, and proximate composition. Crucially, the antioxidant activity was evaluated using the DPPH free radical scavenging assay, and consumer acceptance was assessed through sensory evaluation. The results showed that increasing the concentration of Gracilaria sp. had a significant effect on all observed parameters. As the seaweed concentration increased, there was a notable increase in pH (acidity) and antioxidant activity. Conversely, the viscosity and total lactic acid content tended to decrease. Yoghurt fortified with 20% Gracilaria sp. was identified as the most desirable product, achieving the highest consumer preference score. This specific formulation exhibited an optimal balance of quality attributes, including a pH of 3.76, a viscosity of 270 cP, and a robust antioxidant activity of 42.74%. This research confirms that Gracilaria sp. can be effectively incorporated into yoghurt to create a functional food product with enhanced antioxidant properties. The 20% concentration proved the most effective and demonstrated high consumer acceptance
Yogurt And Cheese as Primary Models For Microparticulated Whey Protein Application: Systematic Review
No full textThis systematic review evaluates the application of microparticulated whey protein (MWP) and their derivatives as fat replacer in yogurt and cheese, based on synthesis of 15 studies. The findings consistently showed that MWP effectively mimics the functional properties of fat, offering promising solution for creating healthier, low-fat dairy products. In both yogurt and cheese models, MWP was found to significantly improve texture and rheology. It enhanced desirable textual attributes by forming a more compact, interconnected protein network. In yogurt, this also led to enhanced water holding capacity and reduced syneresis. The MWP's effectiveness is highly dependent on its specific characteristics, such as particle size and the ratio of native to denatured proteins. The microparticulated form is essential; simple protein isolates do not yield the same textural benefits. MWP also positively impacted sensory attributes. In yogurt, it imparted a smoother, creamier mouthfeel, resulting in higher overall sensory scores. In cheese, MWP generally improved functional properties by softening low-fat cheeses, restoring elasticity, or enhancing spreadability. Studies on petit-suisse, Caciotta, processed cheese, and Cheddar consistently showed better texture, higher moisture retention, and more cohesive microstructures compared to low-fat controls. While not always fully replicating the sensory profile of full-fat products, MWP-fortified low-fat versions consistently outperformed fat-free controls. Overall, MWP serves as a versatile, clean-label fat mimetic that successfully addresses the quality challenges of fat reduction, supporting the development of nutritious and appealing dairy foods
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No full textThis paper establishes explicit evaluations of the 2k-th power mean for generalized cubic Gauss sums. By exploiting analytic techniques and fundamental properties of classical Gauss sums, we derive closed-form expressions for these means. Furthermore, we develop a computationally efficient framework for analyzing higher-order moments of such sums
