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Use of alkali-activated binder as an alternative for bio-based materials manufacturing
No full textInternational audienc
Comparative use of different AI methods for the prediction of concrete compressive strength
No full textInternational audienc
Enzymatic-controlled production and characterization of bio-based oligogalacturonides for application in wheat protection against powdery mildew.
No full textInternational audienc
Valorisation des déchets de sols et de sédiments dans la construction en terre
No full textInternational audienceLes sédiments de dragage et les sols excavés sont des déchets généralement envoyés en décharge. Les déchets de sol et de sédiments proviennent de diverses sources, notamment des activités de construction et d'entretien des ports et des canaux de navigation. Cette étude examine les caractéristiques physico-chimiques et minéralogiques de sédiments fluviaux du fleuve Usumacinta, au Mexique et des sols urbains de Bretagne, en France, afin d'évaluer leur potentiel d'utilisation dans les matériaux de construction en terre. Ces caractéristiques incluent prioritairement la granulométrie, la matière organique, les limites d'Atterberg, la teneur en carbonates, la minéralogie et la teneur en oxydes. L'adéquation des sédiments à différentes applications a été observée grâce à des approches industrielles. Pour observer le comportement mécanique des briques de terre, des blocs de terre comprimée de taille 4*4*16 cm 3 ont été fabriqués à une teneur en humidité optimale. Les échantillons de briques ont été compactés dynamiquement pour augmenter la densification et la résistance des briques. Des blocs de terre cylindriques de grande taille (15 cm de diamètre pour 30 cm de hauteur), ont également été fabriqués pour voir l'influence de la taille. De plus, les sédiments fluviaux ont été renforcés par des fibres de fleurs de palmier à huile (déchets agricoles locaux) avec un ajout de 0 à 5 % en masse de fibres pour observer le comportement des briques en terre. Les sols excavés de Cesson et les sédiments dragués présentent une bonne résistance à la compression de 1,7 et 3 MPa. Avec l'ajout de fibres, la résistance à la flexion des briques à base de sédiments augmente, les valeurs atteignent 3,2 MPa. La résistance à la compression du sol excavé de Cesson diminue s'il est mélangé avec un sol argileux local issu de Crevin.</div
Monitoring of Antioxidant Efficacy of Mangrove-Derived Polyphenols in Linseed Oil by Physicochemical and Fluorescence Methods
No full textInternational audienceThis study was conducted to assess the antioxidant potential of polyphenolic extracts from Rhizophora mucronata and Avicennia marina as natural preservatives in comparison with synthetic butylated hydroxytoluene (BHT) and rosemary extract. Antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and total phenolic content (TPC). Extracts were blended into linseed oil and evaluated for oxidative stability using a 15-day Schaal oven test. Physicochemical analyses, including peroxide value (PV), acid index (AI), p-anisidine value (p-AnV), and thiobarbituric acid reactive substances (TBARS), showed that mangrove-treated oils exhibited the highest stability against oxidation compared to the negative and positive controls. R. mucronata mature leaves presented the highest DPPH inhibition (93.40%) and the lowest TBARS value (0.33 ± 0.0 mg MDA/kg of oil) on day 11. Fluorescence spectroscopy provided complementary and valuable information. Statistical analysis using factorial discriminant analysis (FDA) achieved a classification accuracy of 91.43%, underlining the different oxidative profiles of the treated samples. These findings demonstrated the potential of extracts from mangrove plants as a sustainable alternative to synthetic antioxidants for food preservation. Future studies should explore broader food applications using advanced analytical techniques to optimize their efficiency and performing a series of toxicity evaluations
Polarization texture and sensing application of ferroelectric nanocrystals
No full textInternational audienc
Fostering Girls’ Active Lifestyles: Uncovering Barriers and Levers for Involvement in Physical Activities
No full textInternational audiencePhysical activity (PA) is linked to numerous health advantages, but adolescents typically demonstrate inadequate levels of PA, with girls engaging in less PA than boys. This study aims to explore the factors hindering and promoting PA among girls aged 11–18 years, examining how existing literature addresses these factors through an ecological framework. A scoping review was conducted using the Preferred Reporting Items for Systematic reviews and Meta-Analysis extension for Scoping Reviews protocol. Six databases were searched between October 2022 and November 2024, and 41 articles published between 1993 and 2024 were analyzed. The main barriers to PA for girls were their relationship with their bodies and the influences of peers and teachers, while the main facilitators were social interactions, family or teacher support, and choice of activity. These findings highlight the importance of developing a socioecological framework that addresses personal, interpersonal, and environmental factors to enhance understanding of the issue of girls’ engagement in PA.l'activité physique (AP) est liée à de nombreux avantages pour la santé, mais les adolescents présentent généralement des niveaux d'AP inadéquats, les filles s'adonnant moins à l'AP que les garçons. Cette étude vise à explorer les facteurs qui entravent et favorisent l'AP chez les filles âgées de 11 à 18 ans, en examinant comment la littérature existante aborde ces facteurs à travers un cadre écologique. Une revue de la portée a été réalisée en utilisant le protocole Preferred Reporting Items for Systematic reviews and Meta-Analysis extension for Scoping Reviews (éléments de rapport préférés pour les revues systématiques et les méta-analyses, extension pour les revues de la portée). Six bases de données ont été consultées entre octobre 2022 et novembre 2024, et 41 articles publiés entre 1993 et 2024 ont été analysés. Les principaux obstacles à l'AP pour les filles étaient leur relation avec leur corps et l'influence des pairs et des enseignants, tandis que les principaux facilitateurs étaient les interactions sociales, le soutien de la famille ou de l'enseignant et le choix de l'activité. Ces résultats soulignent l'importance de développer un cadre socio-écologique qui prenne en compte les facteurs personnels, interpersonnels et environnementaux afin d'améliorer la compréhension de la question de l'engagement des filles dans l'AP.Traduit avec DeepL.com (version gratuite
Variations in carbohydrates molar mass distribution during chemical degradation and consequences on fibre strength
No full textInternational audienceIndustrial oxygen-delignified and fully-bleached hardwood kraft pulps were treated with chemicals to provoke carbohydrates depolymerisation: ozone, hypochlorous acid, and cellulase. The degrees of polymerisation (DP) of cellulose obtained by pulp viscosity measurement in Cuen and by size-exclusion chromatography after direct dissolution in DMAc/LiCl indicated the extent of the chemical degradation inflicted to the fibres. Molar mass distributions (MMD) described the carbohydrates depolymerisation patterns. Fibre strength was assessed by measuring the zero-span tensile index at never-dried state. Fibre strength deterioration seemed to be mainly driven by the topochemistry of the cellulose degradation (homogeneous or localised), rather than by its intensity usually measured as an average DP loss. In fact, depolymerisation by cellulase was found critically detrimental to fibres strength whereas ozone and hypochlorous acid induced little harm to the fibres despite a significant cellulose depolymerisation. According to these results, in line with several past studies, fibre strength measurements should be performed systematically as the sole pulp viscosity is an inadequate indicator. Alternatively, albeit being insufficient strength predictors on their own MMD can give valuable insight on the topochemistry of the cellulose degradation, a key aspect when monitoring fibre strength preservation during pulping and bleaching
Sediment-Based Unfired Bricks Reinforced with Waste Flax Fibers: Implementation, Physical Aspects and Kinetics of Air Drying—Part I
No full text(IF 2.5;Q2)International audienceRaw earth bricks made from river sediments and natural fibers are essentially environmentally friendly bricks. They are made from river sediment waste and natural fiber waste, both of which are renewable resources. Sediment-based bricks have been formed from river sediment and flax fibers, the latter being considered as waste. Both types of waste are available in the same region. The study focused on the definition of water content by means of a miniature Proctor test, on the incorporation of short flax fibers of 2, 3 and 4 cm at various dosages and on the shaping by dynamic compaction of bricks of reduced size of 4 cm × 4 cm × 16 cm, dimensions similar to mortar specimens. The air-drying kinetics of the specimens were monitored from manufacture through to stabilization of their mass. The effects of water content, fiber content and fiber length were analyzed. Recommendations are given for the manufacturing and drying of green bricks and natural fibers
