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Production of enriched protein extracts from cultivated Ulva sp. (Chlorophyta, Ulvales) by high-pressure homogenization
No full textInternational audienceThe human food sector plays a crucial role in supporting population growth and ensuring human well-being. In the context of global food security, environmental challenges, and the diversification of protein sources, research into new innovative and sustainable protein sources is essential. In Europe, alternative protein sources such as cultivated seaweed are a promising solution, with potential health benefits and increased sustainability. This study investigated the use of high-pressure homogenization (HPH) to obtain protein-enriched fractions from dried biomass of cultivated Ulva sp. The biochemical composition, physical-chemistry (FTIR and granulometric analysis) and the biological activities of the supernatant and residue fractions were evaluated after HPH treatment at pressures of 0, 600, 800, and 1000 bars. Results showed that, depending on their nature, pressure significantly influenced the biochemical composition and separation of compounds into the residue and supernatant, and underlined the potential of HPH to enhance protein recovery from Ulva sp. HPH facilitated separation of ulvan polysaccharides, known for their anti-nutritional effects, and from the protein fraction with high recovery yields of 60.0% protein in the residue. The highest protein content was found in residues at 1000 bars (8.93%) compared to in the crude extract (4.1%). Amino acid analysis revealed that essential amino acids accounted for 42% of total amino acids in the Ulva sp. fraction, with high levels of valine, leucine and methionine. The ulvan fraction (concentration of rhamnose, uronic acids and sulphate groups) was preferentially extracted at 1000 bars, where the supernatants contained 28.6 ± 4.5% of uronic acids, 23.2 ± 4.9% of sulfate groups, and 3.72 ± 0.31% of rhamnose (p< 0.05).These results provide clear evidence that HPH is effective in disrupting the cell wall and facilitating the release of compounds of interest. These results also suggest that the HPH process could position cultivated Ulva sp. as an important potential source of food protein
Caractérisation du frottement inter-mèches de verre : confrontation essais/calculs par éléments finis selon une formulation ALE
No full textInternational audienceCaractérisation du frottement inter-mèches de verre : confrontation essais/calculs par éléments finis selon une formulation AL
Analysis of turbulent flow and thermal performance of plate-pin fins heat sink fitted with a shield in the bypass
No full textInternational audienceIn this article, a numerical analysis study has been performed to investigate the dynamic and thermal performances of a plate pin fin heat sink. Four types of pin fin shape are used, such as square (oriented 45° relative to the air flow), cylindrical, elliptical, and drop-form, and a transverse fin (shield) with adjustable height (Hs = 6, 10 and 13 mm) arranged in the bypass. The range of Reynolds number is studied between Re = 2 × 103 and Re = 12 × 103. The finite volume method was used to solve the governing equations. The thermal and dynamic results are presented in terms of Nusselt number and friction factor respectively; and as a function of Reynolds number. All the cases were compared with a plate fin heat sink. It is found that an enhancement of performance showed by implanting the pin-fin between the plate fin and fitting a shield in the bypass
Enhancing Quadcopter Stability and Dynamic Control Through Brushless DC Motor Based on Experimental Data-Driven Models
No full textInternational audienceThe primary challenge in controlling the dynamics of a Quadcopter is achieving stability, which ensures smoother and more accurate movements. This paper proposes a strategy for achieving stability in a single degree of freedom (1-DOF) system case and for one frame. The strategy involves simulating the proposed model using experimental data from various cases. Furthermore, the system is controlled by a Brushless DC electrical motor connected to an electronic inverter, which drives a propeller to generate the necessary aerodynamic power for Quadcopter takeoff. By simulating the inverter and the motor, an aerodynamic model, based on experimental data and representing the arm model mathematically, is proposed. Appropriate parameters are determined to stabilize the system. Hence, the results demonstrate the efficiency of the proposed system and validate, experimentally, the effectiveness of the proposed strategy in achieving stability
Une mutation dans l'intérêt du service est une mesure d'ordre intérieur qui ne révèle en principe pas un harcèlement moral
No full textInternational audienceNote sous CAA Bordeaux, 4 novembre 2024, no 22BX02471 (inédit au Lebon
Rayon fibre rope: A biodegradable alternative for marine use?
No full textInternational audienceRayon fibres are well-known materials that were primarily utilised as reinforcement in tyres. Today these materials are perceived as a promising substitute for synthetic fibres, exhibiting good mechanical characteristics and biodegradation in many environments. This paper investigates their potential use for marine structures. It first describes the tensile properties of the fibres and their derived yarns and ropes. These properties are then monitored during seawater ageing and the ultimate biodegradation is characterised by respirometry tests. Both material scales demonstrate rapid degradation rates under biotic conditions (90 % strength reduction after 2 weeks for yarns and 6 months for small ropes) and a relative stability in abiotic conditions. Additionally, the fibres show rapid bio-assimilation rates. The rope construction is demonstrated to have a significant impact on the degradation kinetics, suggesting possible strategies to enhance durability. The results indicate that these rayon fibre ropes may offer an attractive alternative to synthetic fibre ropes to reduce impact where there is a high risk of rope loss at sea
Le rôle des dispositifs de gestion dans le processus de création de valeur publique :étude du déploiement des schémas directeurs immobiliers et énergétiques au sein du secteur public
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Échecs subis, échecs concertés. Approches typologiques de mariages manqués au regard du droit canonique médiéval et de sa mise en oeuvre juridictionnelle (XI -XV siècle)
No full textInternational audienceThis paper presents a repertoire of marriages or marriage projects of the medieval aristocracy, captured for what they failed, in their failure, and apprehended according to a canonical reading grid, in the prism of medieval canon law, of the reflection of canonists and of the devices of social regulation made possible by justice.Cet article présente un répertoire de mariages ou de projets de mariage de l’aristocratie médiévale, saisis pour ce qu’ils ont failli, dans leur échec, et appréhendés selon une grille de lecture canonique, au prisme du droit médiéval de l’Église, de la réflexion des canonistes et des dispositifs de régulation sociale rendus possible par la justice