HAL - Université de Franche-Comté
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Évaluation de l'énergie pendant le saut à la perche à l’aide de la capture de mouvement par centrale inertielle : une étude préliminaire
No full textInternational audienc
Où sont les légumineuses dans les terroirs de savane sud-soudanienne ?
No full textCe volume fait suite aux Rencontres Francophone Légumineuses (RFL) de mars 2024 organisées par le Cirad, INRAE, Terres Inovia et Terres Univia, et co-organisé par l'Institut Sénégalais de Recherches Agricoles (ISRA). Ce rendez-vous unique entre tous les acteurs du développement, des filières et de la recherche sur les légumineuses à graines et fourragères. L’occasion de croiser les regards, partager les connaissances et accélérer l’innovation autour des légumineuses.Les RFLs s’intéressent aux légumineuses à graines, fourragères ou ligneuses, et visent à couvrir la diversité des systèmes de production, ainsi que la diversité des usages : alimentation humaine, animale et non-alimentaire.Les légumineuses sont un levier majeur pour relever les défis mondiaux du changement climatique et de la sécurité alimentaire et nutritionnelle. Partout dans le monde, elles disposent d’un rôle stratégique : atouts nutritionnels, souveraineté protéique et alimentaire. Les nombreuses espèces de légumineuses constituent également un formidable vivier d’innovations alimentaires.National audienceWith mechanized farming in sudanian climate terroirs (maize, cotton), legumes associated with hardy cereals have both declined. Taking the case of south-west Burkina Faso (social transect of 8 villages, 3 lowlands), on the basis of recent detailed data at individual and farm level, the paper explores the status of legumes, variations and drivers. In fields on dry soils, legumes are still grown in pure stand or in associations, but have fallen since the 1970s, especially in "bush fields". Even cash cropping of groundnuts has given way to cotton. Small non-cotton farms and women still rely on legumes. Large farms have limited them to their food needs, but are testing soybeans, in association or rotation with cotton and maize. Farms disappointed with cotton are interested in groundnut and cowpea in pure stand.Résumé : Avec la culture mécanisée dans les terroirs en climat soudanien (maïs, cotonnier), les céréales rustiques ont reculé, avec leurs légumineuses associées. En prenant le cas du Sud-Ouest du Burkina Faso (transect social de 8 villages, 3 bas-fonds), sur la base de données détaillées récentes à l’échelle individu et exploitation, l’article explore le statut des légumineuses, leurs variations et facteurs sousjacents. Dans les sols secs, les légumineuses restent cultivées en pur ou en association, mais ont chuté depuis les années 1970, surtout dans les « champs de brousse ». Même l’arachide de rente a reculé face au cotonnier. Les petites exploitations sans cotonnier ainsi que les femmes misent encore sur les légumineuses. Les grandes exploitations les ont limitées à leurs besoins alimentaires, mais testent le soja, en association ou rotation avec cotonnier et maïs. Les exploitations déçues du cotonnier sont intéressées par l’arachide et le niébé en culture pure
Transport mechanisms analysis of large-size proton exchange membrane fuel cells with novel integrated structure under ultra-high current densities
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Typology, diversity and ecology of the vegetation of Djebel Tessala (Algeria)
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Sufficiency power consideration to run a workload on renewable energy operated datacenter
No full textInternational audienceDatacenters are an essential part of the internet, but their continuous development requires finding sustainablesolutions to limit their impact on climate change. The Datazero2 project aims to design datacenters runningsolely on local renewable energy. In this paper, we tackle the problem of computing the minimum power demandto process a workload under quality of service constraint in a datacenter operated with renewable energy. To solvethis problem, we propose a binary search algorithm that requires the computation of machine configurations withmaximum computing power. When machines are heterogeneous, we face the problem of choosing the machinesand their DVFS (Dynamic Voltage and Frequency Scaling) state. A MILP (Mixed-Integer Linear Programming),to find the optimal solution, and four heuristics that give satisfactory results in a reasonable time are proposed.simulations show that the best heuristics reach an average deviation from the optimal solution of 0.03% to 0.65%.The binary search algorithm is challenged against a real workload to assess the impact of flexibility on the qualityof service
Impaired unsaturated fatty acid elongation alters mitochondrial function and accelerates metabolic dysfunction-associated steatohepatitis progression
No full textInternational audienceAlthough qualitative and quantitative alterations in liver Polyunsaturated Fatty Acids (PUFAs) are observed in MASH in humans, a causal relationship of PUFAs biosynthetic pathways is yet to be clarified. ELOVL5, an essential enzyme in PUFA elongation regulates hepatic triglyceride metabolism. Nonetheless, the long-term consequences of elongase disruption, particularly in murine models of MASH, have not been evaluated
Synthesis, crystal structures, DFT calculations, and oxygen radical absorbance capacity of 5-arylidene-thiazolidine-2,4-dione derivatives
No full textInternational audienceA new green methodology has been developed for the synthesis of a series of substituted 5-arylidene-2,4-thiazolidinediones (ATZDs) 3a-q through Knoevenagel condensation, using barium hydroxide as an efficient heterogeneous catalyst. All compounds were characterized by H-1 NMR, C-13 NMR, and HRMS spectroscopy. Additionally, seven compounds were analyzed by X-ray diffraction (XRD). Furthermore, some selected TZD derivatives were screened for their antioxidant activity using oxygen radical absorbance capacity (ORAC) assays. The results showed that five compounds exhibited excellent antioxidant properties, with ORAC values ranging from 4.73 TE to 6.31 TE, surpassing the reference antioxidants ferulic acid (3.70 TE) and melatonin (2.45 TE). Computational investigations based on the DFT method revealed that these compounds exert their antioxidant activity primarily through the HAT mechanism, preferentially from the OH bond rather than the NH bond. This study highlights the advantages of this methodology, providing products of high purity, with good yields and short reaction times, and proposes 5-arylidene-thiazolidine-2,4-dione derivatives as promising antioxidants
AlphaPEM: an open-source dynamic 1D physics-based PEM fuel cell model for embedded applications
No full textInternational audienceThe urgency of the energy transition requires improving the performance and longevity of hydrogen technologies. AlphaPEM is a dynamic one-dimensional (1D) physics-based PEM fuel cell system simulator, programmed in Python and experimentally validated. It offers a good balance between accuracy and execution speed. The modular architecture allows for addition of new features, and it has a user-friendly graphical interface. An automatic calibration method is proposed to match the model to the studied fuel cell. The software provides information on the internal states of the system in response to any current density and can produce polarization and EIS curves. AlphaPEM facilitates the use of a model in embedded conditions, allowing real-time modification of the fuel cell’s operating conditions
Reinforcement learning-based maintenance scheduling for a stochastic deteriorating fuel cell considering stack-to-stack heterogeneity
No full textInternational audienceMaintenance scheduling of stack replacement is indispensable for achieving the durable and reliable operation of fuel cell systems. However, the related maintenance actions for minimizing long-term risk and cost in fuel cells constitute a complex optimization problem. Moreover, the complicated stochastic degradation behavior of fuel cell stacks hid the development of maintenance scheduling policies. Thus, the action phase of maintenance scheduling in fuel cell prognostics and health management (PHM) studies and stochastic degradation modeling are identified as two major research gaps. This paper investigates the maintenance scheduling of a stochastically deteriorating fuel cell stack exposed to deterioration heterogeneity. The maintenance problem consists in finding preventive control limits and inspection intervals that minimize total maintenance costs. A proximal policy optimization (PPO) based method is used to develop the maintenance strategy by describing the maintenance scheduling problem as a Markov decision process (MDP). Investigation results show that a steeper preventive control limit and more conservative inspection intervals are needed when heterogeneity exists. The proposed PPO-based method can solve the MDP and obtain more general maintenance policies considering the stochastic deterioration of fuel cell systems. The formulation of a condition-based maintenance scheduling problem, the reinforcement learning-based solution, and the investigation of stack-to-stack degradation heterogeneity’s influence constitute this work’s main novelties. This study provides useful insights for the development of fuel cell PHM studies, particularly within the action phase, helping to enhance the durability and reliability of fuel cell systems by better operating them. So the paper could be useful for different fuel cell applications. Meanwhile, the framework discussed in the paper, i.e., developing reinforcement learning for maintenance planning, is generic enough to be referred to in other related applications