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Probing gluon saturation with forward di-hadron correlations in proton-nucleus collisions
No full textInternational audienceWe present a detailed numerical investigation of semi-inclusive forward di-hadron production in proton-nucleus collisions employing the Color Glass Condensate effective theory. We focus on the regime where di-hadrons are produced nearly back-to-back in the transverse plane, thereby justifying a transverse-momentum-dependent factorization approach in terms of small- gluon distributions. Our computation integrates several key elements: i) non-linear rapidity evolution via the Balitsky-Kovchegov equation with running coupling, ii) both perturbative and non-perturbative Sudakov resummation, and iii) a phenomenologically constrained model for the initial conditions for small- gluon distributions. We compare this phenomenological framework to experimental data from the STAR Collaboration on azimuthal correlations in forward di-pion production in both proton-proton and proton-gold collisions. We analyze the systematic theoretical uncertainties associated with the saturation scales of nuclei at the initial scale for rapidity evolution and with those associated with the hadronization process. Finally, we make predictions for the kinematics anticipated to be covered by the ALICE Forward Calorimeter (FoCal) upgrade at the Large Hadron Collider
Optimal parameter extraction of fuel cells based on interval branch-and-bound optimization algorithm
No full textInternational audienceFuel cells play an important role in reducing environmental impacts to produce cleaner electricity. Numerical models are used to simulate their performance and build efficient observers in real use. The accuracy of these models is a major concern, as they can be parameterized by several values. Most of the previous works study the estimation of these parameters using various metaheuristics. While these methods are stochastic and do not provide any proof of optimality, the current paper introduces a global optimization method to accurately bound the optimal root mean square error between the parameterized model and some experimental data. The proposed algorithm is based on a deterministic Interval Branch-and-Bound optimization (IBBO) framework. Interval arithmetic ensures set-based computations to safely bound the objective function value. Four types of fuel cells, with their experimental data, are used to demonstrate the efficiency of the proposed methods. IBBO results are compared with some competing optimization methods used in the literature. They show a better accuracy for the computed feasible solutions (upper bounds) and a guaranteed value of the best possible solutions (lower bounds). This last information is not possible to obtain with metaheuristic algorithms. Compared to other Branch-and-Bound algorithms, IBBO proposes a new mix of mechanisms (e.g. advanced constraint propagation, specific search heuristic and feasible point finding method). Due to the deterministic nature of IBBO, results can be repeated. Its convergence analysis is detailed on four fuel cells from which a real test system based on Scribner technology is used to demonstrate the accuracy and robustness of IBBO on several usage scenarios
Education critique: Ce que peut l'histoire
No full textInternational audienceL’esprit critique deviendrait-il une formule générique trop malléable pour être opératoire ? Ce livre s’attaque à une notion essentielle, mais trop souvent galvaudée. Il prend pour objet l’histoire en tant que pratique culturelle de critique documentaire construite au fil des siècles. Il interroge ce que peut l’histoire en matière d’éducation critique pour répondre à la surabondance (dés-)informationnelle de notre époque. Parce que la critique des récits et des témoignages joue un rôle prépondérant dans la pratique historienne, l’auteur et l’autrice y puisent les conditions d’un renouvellement de l’enseignement de l’histoire. Si l’on doute de tout, aucune connaissance fondée n'est possible. Mais sans mise en doute, le monde des idées et des préjugés l’emporte sur la réalité des faits. Résolument inscrit dans les champs de l’histoire et de la didactique de l’histoire, l’ouvrage donne corps à des critères partagés pour confronter des interprétations et élabore des conditions à leur apprentissage. Pour y parvenir, il déploie une analogie entre le fonctionnement de la cour d’assises et la classe d’histoire afin de caractériser un décorum et les instruments d’une enquête réellement critique et adaptée à l’école. L’éducation critique se révèle dans l’apprentissage de savoirs et de démarches pour juger par soi-même
On the performance of radiocarbon and quartz OSL dating in macrotidal estuarine environments: Four case studies from Western France
No full textInternational audienceThe study of estuarine sedimentary archives provides valuable insights into their geomorphological evolution over the past two centuries, enhancing our understanding of estuarine responses to climate change. Establishing a reliable and precise geochronological framework is therefore essential for monitoring these changes. This study evaluates the performance of quartz Single-Aliquot Regenerative (SAR) OSL and AMS 14C dating in four estuaries along the western coast of France. The results are compared with cartographic data, serving as an independent age control. Of the 14 OSL dated samples, 10 yield depositional ages consistent with cartographic data, whereas the remaining 4 appear to overestimate ages by 20–100 years. In contrast, AMS 14C dating reveals numerous stratigraphic inversions, with at least 12 out of the 16 measured samples overestimating the depositional age in some cases by up to 5000 years, in total disagreement with cartographic data. The discrepancy between the OSL and radiocarbon ages reflects the constant reworking of allochthonous material, to which is added the further uncertainty associated with the local reservoir age. These factors fundamentally limit the reliability of 14C dating regardless of the material analyzed. By contrast, the OSL signal displays remarkable resilience, with any age overestimation linked to partial bleaching remaining minor (on the order of decades) compared with the errors affecting 14C ages. This underscores the capacity of OSL dating to resolve short-term environmental changes and positions it as the most reliable tool for constructing high-resolution chronologies of the last centuries in macrotidal estuarine settings
Expanding the application of the TAIL rating scheme to schools: schoolTAIL
No full textInternational audienceSchools have no universally adopted scheme for rating indoor environmental quality (IEQ). In this work, we adapted the TAIL rating scheme that was developed for assessing IEQ in offices and hotels so that it can be used in schools. The original TAIL scheme assesses thermal, acoustic, and luminous conditions, along with indoor air quality, using ten measured parameters and one evaluated through observation and one through simulation. We supplemented it with two other parameters, reverberation time and the concentration of nitrogen dioxide, to adequately characterize a classroom's IEQ. We have also updated the ranges for PM2.5 in accordance with the latest updates to the WHO air quality guidelines. Otherwise, we kept the principles used to develop the original TAIL rating scheme unchanged. We used measurements from schools reported in the published literature to identify the relevant parameters. We refer to the newly developed scheme as TAIL for schools, in short, schoolTAIL. We examined its feasibility using an existing database, with measurements made in 308 randomly selected schools as part of a nationwide survey in France. The new scheme turned out to be a valuable tool for identifying potential problems and prioritizing IEQ remediations, providing a comprehensive yet easy-tounderstand overview of the current situation in school buildings
Online process monitoring under quality data scarcity: Self-starting truncated EWMA schemes for time between events
No full textInternational audienceThis study proposes one-sided self-starting truncated EWMA (SST-EWMA) control charts for effective high-quality process monitoring in situations where extensive in-control time-between-events (TBE) observations are unavailable.By constructing a pivot quantity and establishing variable mappings, a selfstarting framework specifically tailored for Gamma distributed TBE observations is developed. The integration of a variable truncation mechanism into this framework further enhances sensitivity to small to moderate process shifts. To investigate the detection properties of the proposed schemes, simulation were conducted to examine the effects of the shape parameter α, the number of reference TBE observations M , and the smoothing parameter λ on the average time to signal (ATS). Based on the simulation results, guidelines are provided for achieving ATS performance comparable to that of the corresponding knownparameter schemes. Comparative analysis demonstrates that, although slightly inferior to the one-sided TEWMA TBE charts under known parameters, the proposed charts exhibit superior adaptability in scenarios with scarce TBE data, and also outperform the existing self-starting EWMA TBE chart, validating the effectiveness of the variable truncation mechanism. Finally, two case studies are</div
Evolution of the electrical conductivity of pound cake during baking by ohmic heating
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Wadsley-Roth FeNb11O29 as negative electrode material for lithium solid-state batteries
No full textInternational audienceFeNb 11 O 29 and Li 6 PS 5 Cl but revealed an interfacial degradation, with a resistive Li 2 S/oxide-rich interface, consistent with impedance growth. These findings highlight the critical role of microstructural and interfacial optimisation in the electrode composites and establish FeNb 11 O 29 as a promising candidate for high-rate solidstate batteries.</div
Flash Profile method, is it suitable for complex multi-layered products? Application to strawberry-filled biscuits: a “SWEET project”
No full textInternational audienceComposite foods are consumed daily, but understanding their sensory properties is a major challenge. This study aims to evaluate the efficiency of Flash Profile (FP) method to characterize strawberry-filled biscuits properties, in a context of sugar reduction. Investigations were carried out on fillings (with/without added sugar, with/ without strawberry aroma), then biscuits (with sugar or maltitol or sorbitol, with/without vanilla aroma) and finally on the complex fruit-filled biscuits, corresponding to a progressive matrix complexification strategy.FP allowed a discrimination of the products for the 3 matrices according to their formulation and flavouring. Fruit fillings and biscuits were described with both flavour and texture attributes, whereas fruit-filled biscuits were mainly described with texture attributes. This texture predominance could result from complex changes of texture perceived during chewing. Panellists may also have focused on the first perceived characteristics or on the product's most distinguishing features to ease the task.FP was efficient to discriminate samples in each set of samples according to formulation. The characteristics allowing differentiation between samples varied depending on the matrix. Flavour attributes were mainly used for fluid matrices while texture was dominant for solid matrices. In our study, all panellists evaluated the 3 sets of products in the same order which could have influence their evaluation of complex products during the last session. Further investigations about the evaluation of complex solid products with FP may determine if texture is always dominant, even with a lower number of products.</p