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Équilibrage de ligne d'assemblage aéronautique sous contrainte de ressources avec effet d'apprentissage : une approche de programmation par contraintes
No full textInternational audienceL'équilibrage des lignes d'assemblage en aéronautique est un défi majeur dans le domaine de la production. Les usines aéronautiques sont généralement conçues avec une cadence de production prédéterminée, mais le système de production nécessite un temps d'adaptation au démarrage. Ce phénomène, appelé effet d'apprentissage, correspond à l'amélioration progressive de l'efficacité par la répétition des tâches, réduisant ainsi leur durée. Cependant, la stabilité de la ligne est également un facteur clé, car toute modification du processus de production engendre un coût. Cette étude utilise la programmation par contraintes pour optimiser l'équilibrage des lignes d'assemblage, en intégrant l'effet d'apprentissage afin de gérer le compromis entre l'atteinte d'une cadence de production cible et la minimisation des ajustements apportés à la ligne d'assemblage
Parametric and Statistical Optimization of Key Operating Conditions for Efficient Single-Step Hydrodeoxygenation of Bioglycerol to Propylene over the MoO<i><sub>x</sub></i>-Based Catalyst
No full textInternational audienceSignificant progress has been made in catalyst design and reaction steps’ fine-tuning and promotion in the bioglycerol-to-propylene (GTP) reaction; however, suboptimal conditions often result in incomplete glycerol hydrodeoxygenation or excessive propylene hydrogenation, hence limiting the process efficiency. In this study, high-throughput testing was combined with response surface methodology (RSM) and AspenPlus process modeling (APM) to optimize key GTP parameters─temperature, pressure, H2/glycerol molar ratio, and space velocity─using a highly active MoOx-based catalyst, with the goals of maximizing propylene yield, minimizing byproducts, and preliminary assessing GTP process cost. The GTP route is mostly governed by temperature and H2 availability, which drive two major pathways: (i) at low temperatures and high H2 pressure, allyl alcohol undergoes direct hydrogenolysis to propylene, whereas in low-H2 environments, it isomerizes to propionaldehyde; and (ii) higher temperatures promote both the hydrogenation of allyl alcohol and propionaldehyde, followed by thermodynamically driven dehydration of 1-propanol to propylene. Balanced mixing between glycerol, H2, and the catalyst’s active sites is crucial for enhancing propylene formation. Face-centered central composite design within RSM predicted a maximum propylene yield of 71.83% under optimal GTP conditions: T ∼ 358.5 °C, H2/glycerol (mol.) ∼ 80.45, WHSV ∼ 9.5 h–1, and P ∼ 50 bar. The predictive models showed strong agreement with experimental data (R2 = 91.29%, and R2adj = 83.44%). Experimental validation tests repeated three times under these optimized conditions yielded 70.77–72.49% biopropylene, with relative errors below 1.47%, confirming the model’s accuracy and reliability. The preliminary APM-based assessment confirms the technical feasibility of producing chemical-grade biopropylene (95 mol %) from bioglycerol/water mixtures (10–30 wt %), while also highlighting current economic challenges. It identifies new avenues for process optimization and underscores the environmental benefits of the single-step GTP route, in line with zero-carbon and circular economy objectives
Dramatherapy in an adapted school: what identity boxes reveal
No full textInternational audienceBackground Dramatherapy is increasingly used in special education contexts to support young people facing academic, emotional, and social challenges. In France, Regional Institutions for Adapted Education (EREA—Etablissement Régional d'Enseignement Adapté) serve vulnerable adolescents, often stigmatized and marginalized in mainstream schooling. This study explores the use of identity boxes as both a research method and a therapeutic tool in such a context. Aims The study investigates how identity boxes, integrated into a dramatherapy program, can foster emotional expression, self-reflection, and improved peer relationships among students in an adapted education setting. Methods Conducted as part of a research project, the intervention involved ten dramatherapy workshops led by a certified dramatherapist and conducted with two groups of final- and penultimate-year students. A control group, who did not take part in the workshops, nonetheless participated in two sessions dedicated to the construction of identity boxes, delivered as part of their visual arts classes. The study adopted an ethnographic approach, combining participant observation, semi-structured interviews, and the analysis of identity boxes and the associated narratives. Results Students in the dramatherapy group demonstrated enhanced emotional introspection, more positive peer interactions, and a stronger sense of Self, while the control group showed fewer developments. The identity boxes served both as expressive objects and as reflective instruments, offering deep insights into students' evolving self-perception and experiences of inclusion. Conclusions This study highlights the value of combining dramatherapy and creative visual methods in special educational settings. It underscores the importance of arts-based interventions in fostering emotional wellbeing and inclusion for students with disabilities and social difficulties, suggesting future applications in similar institutional contexts
On the enhanced photocatalytic activity of N-doped carbon dots
No full textInternational audienceCarbon nanostructures (dots) have emerged as a novel and sustainable alternative for the photocatalytic degradation of water pollutants. This work presents the synthesis of multidoped carbon nanomaterials (CNs) using a microwave-assisted method. Overall, four types of carbon nanostructures were obtained: (i) nitrogen-doped CNs (N-CDs), (ii) nitrogen and sulfur co-doped CNs (N,S-CNs), (iii) nitrogen and phosphorus co-doped CNs (N,P-CNs), and (iv) nitrogen, sulfur, and phosphorus multi-doped CNs (N,S,P-CNs). The characterization of these nanoparticles was performed via Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), enabling the identification of stretching modes corresponding to C[double bond, length as m-dash]O, C–N, and N–H functional groups. Additionally, UV-vis and fluorescence spectroscopies allowed the detection of n–π* and π–π* absorption bands at ∼325 and 400 nm, along with light emission at 438 nm. High-resolution transmission electron microscopy (TEM) characterization confirmed structural and morphological differences between the nanomaterials, which exhibited sizes ranging from 1 to 100 nm, depending on the chemical composition of the starting precursors. Finally, the photocatalytic activity of the CNs towards the degradation of toluidine blue was assessed, considering the effects of morphology, composition, and both catalyst and dye concentration on photodegradation. Such a catalytic process followed pseudo-first-order kinetics, where N-CDs exhibited the highest potential for toluidine blue degradation. Our results highlight that the photocatalytic activity of carbon nanomaterials is a multifactorial process essentially driven by the formation of OH radicals, where doping and particle morphology also play a combined role in photocatalysis. This work opens a route for understanding the chemical composition and structure of photocatalytic nanocarbons and their application to the degradation of organic pollutants in water, thus offering a sustainable alternative for wastewater treatment
Impaired cerebral hemodynamics and oxygenation in type 2 diabetes: insights into insulin resistance and hyperglycemia effects
No full textInternational audienceAimsEmerging evidence suggests Type 2 diabetes (T2D) may adversely affect cerebral hemodynamics and oxygenation. This study aimed to explore the impact of uncomplicated T2D on cerebral hemodynamics and oxygenation during maximal exercise.MethodsIn a comparative clinical trial, 30 matched pairs of subjects with obesity, stratified by T2D status, were enrolled. Hemodynamic and oxygenation parameters were assessed during incremental maximal exercise. Additionally, physical activity levels, lipid profiles, and insulin resistance markers were evaluated.ResultsParticipants with T2D exhibited significantly impaired cerebral blood volume (total hemoglobin) and oxygenation (oxygenated hemoglobin) compared to controls, especially at exercise intensities above 80 % of VO2peak. This impairment was independent of differences in arterial carbon dioxide partial pressure (PaCO2) levels between the groups at peak exercise (P > 0.05, PaCO2 34.4 ± 3.2 vs 34.5 ± 1.3 mmHg). Moreover, individuals with T2D had a lower estimated glucose disposal rate (eGDR) compared to the control group (P = 0.02; 7.4 ± 2.4 vs 9.27 ± 0.97 mg/kg/min).ConclusionsOur findings indicate that insulin resistance and hyperglycemia in T2D contribute to impaired cerebral hemodynamics and oxygenation, even before clinical signs of microangiopathy appear. These alterations could have significant implications for cognitive function and overall brain health in individuals with T2D
From order lifting to social ranking: recovering preferences from partial extensions
No full textInternational audienceSeveral methods have been introduced in the literature to extend preferences over items from a population to preferences over the groups they may form - a problem known as the Order Lifting problem. The converse matter of deducing preferences over items from expressed preferences over the coalitions that may be formed within a population - a problem known as the Social Ranking Problem - has also been studied more recently. In this paper, we investigate the links between these two problems: after an examination of the general case, we consider the impact of missing information, by studying which social ranking methods allow for the most accurate recovery of initial preferences over items, depending on the amount of missing information about coalitions. Finally, we consider the specific case in which preferences are only expressed over coalitions of same size, and examine the accuracy of social ranking methods when faced with impartial information about preferences over -sized coalitions
solQHealer: Quantum Procedures for Rendering Infeasible Solutions Feasible: A Proof of Concept with the Maximum Independent Set Problem and 3-SAT
No full textInternational audienceOver the past decade, the usefulness of quantum annealing hardware for combinatorial optimization has been the subject of active debate. Although current analog quantum machines do not guarantee optimality, operating instead as heuristic solvers, the technology is evolving rapidly. Beyond performance alone, this emerging technologies offers fundamentally new approaches to problem-solving that are not readily accessible to classical exact methods particularly in dynamic environments or online optimization settings. This paper focuses on one such approaches: Reverse Quantum Annealing (RQA). Unlike classical exact methods, RQA allows the optimization process to begin from an initial infeasible solution by embedding it directly into the qubits' initial state. We leverage this capability by formulating problem constraints as penalty terms within Quadratic Unconstrained Binary Optimization (QUBO) models, thereby preserving infeasible solutions within the quantum search space. We propose iterative strategies that apply RQA in three distinct modes to rapidly repair infeasible solutions. These methods are evaluated on two well-known NP-hard problems: the Maximum Independent Set (MIS) and the 3-SAT problem. Our results demonstrate the effectiveness of RQA in steering infeasible configurations toward feasibility, offering B Samuel Deleplanque</div
Glyoxylic Acid in Morita–Baylis–Hillman Reactions: One-step Connection of a Polar C2 Fragment for Surfactant Design
No full textInternational audienceThe use of glyoxylic acid (GA) in Morita–Baylis–Hillman (MBH) reactions with alkyl acrylates was investigated with the aim of designing original amphiphilic compounds. The optimized reaction conditions using either DABCO or 3-hydroxyquinuclidine in ethanol resulted in good to excellent yields of MBH adducts by reacting the commercial GA aqueous solution with medium to long alkyl chain acrylates. The structural characterization confirmed the successful formation of well-defined amphiphilic architectures. Preliminary investigations of their behavior in aqueous media revealed that nonionic GAO amphiphiles effectively reduce surface tension, although their high Krafft temperatures (T > 85 °C) limit their solubility at ambient temperature. The introduction of ionic functionality, as in GAO8Na, resulted in improved water solubility with a significantly lower Krafft temperature (T < 5 °C) and a higher critical micelle concentration (CMC) than its nonionic counterpart. The hydrophilic–lipophilic balance, evaluated using the PIT-slope method, suggests that GAOn compounds exhibit a predominantly lipophilic character, making them promising candidates for W/O emulsification applications
