Dynamique spatio-temporelle d'un jet d'air libre évoluant à nombre de Reynolds modéré

Ce travail présente des résultats expérimentaux pour un jet d'air libre injecté dans l'air ambiant à nombre de Reynolds 1600. La dynamique du jet est observée par visualisation des images de l'écoulement des fumées d'encens enregistrées par une caméra rapide. Une analyse temporelle des séries d'images acquises a permis de mettre en évidence les détails du comportement de l'écoulement. Les résultats démontrent l'existence d'anneaux tourbillonnaires au bord du jet. La taille, la distribution et la fréquence d'apparition de ces anneaux tourbillonnaires sont examinées

Unpublished Mediterranean records of marine alien and cryptogenic species

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta

Visualisation et mesures expérimentales dans un jet rond évoluant à nombre de Reynolds modéré

L’objectif de ce travail est d’étudier les instabilités de Kelvin-Helmholtz apparaissant dans un jet de fluide monophasique évoluant à nombres de Reynolds modérés. L’étude porte sur la région proche de la buse d’éjection (la zone de transition), et elle est localisée sur l’évolution dans l’espace et dans le temps des instabilités aérodynamiques spécifiques à ce type d’écoulement. Dans cette étude expérimentale, les instabilités sont décrites qualitativement puis quantitativement à l’aide de la technique de tomographie par plan laser associée aux opérateurs de traitement d’images. On s’intéresse en particulier à l’étude des structures générées par l’instabilité des jets ainsi que la détermination de leurs paramètres caractéristiques

Etude tomographique des instabilités d'un jet axisymétrique à bas nombre de Reynolds par PIV et analyse des frontières

L'étude développée dans ce mémoire constitue une contribution par des moyens numériques et expérimentaux à la caractérisation des écoulements de type jet. A partir du développement d'instabilités hydrodynamiques dans un écoulement de type jet axisymétrique libre évoluant à bas nombres de Reynolds, nous avons étudié plus précisément la transition à la turbulence. L'étude numérique consiste à une résolution numérique des équations de Navier-Stockes régissant les écoulements de type jet circulaire et isotherme en régime laminaire. Notre travail a été orienté particulièrement vers l'étude de l'influence des conditions d'émission du gaz à la section d'injection sur le comportement aérodynamique du jet. Nous présentons également des résultats concernant le champ de concentration. Dans la partie expérimentale, la technique de PIV et la visualisation des écoulements associée aux traitements d'images ont été utilisées afin d'étudier le champ de vitesse, les instabilités hydrodynamiques et la transition à la turbulence dans ce type d'écoulements. L'apparition des instabilités, à partir des modes sinueux et variqueux, et leur évolution vers l'état chaotique (turbulent) sont suivies en fonction du paramètre principal à savoir le nombre de Reynolds.The study developed in this memory constitutes a contribution by numerical and experimental means to the characterization of the jet flow type. From the development of hydrodynamic instabilities in a free axisymmetry jet flow evolving at low Reynolds numbers, we more precisely studied the transition to turbulence. The numeric study is relative to a numeric resolution of Navier-Stockes equations governing circular and isotherm jet flow in laminar engine. Our work has been oriented particularly towards the influence of the emission conditions (at the nozzle exit) on the jet aerodynamic behavior. We also present results concerning the concentration field. In the experimental part, the PIV technique and the flow visualization associated with image processing were used to study the velocity field, the hydrodynamic instabilities and the transition to turbulence in this type of flows. In the sinuous and varicose modes, the appearance and of instabilities their evolution towards the chaotic state (turbulent) are followed according to the principal parameter, the Reynolds number.ST ETIENNE-BU Sciences (422182103) / SudocSudocFranceF

Enzyme-aided release of bioactive compounds from coriander (Coriandrum sativum L.) seeds and their residue by-products and evaluation of their antioxidant activity

International audienc

Reference Values of Physical Performance in Handball Players Aged 13–19 Years: Taking into Account Their Biological Maturity

Biological maturity status significantly influences success in handball, impacting an athlete’s performance and overall development. This study aimed to examine the anthropometric and physical performance variables concerning age and maturity status, establishing reference values for physical performance among Tunisian players. A total of 560 handball players (309 males and 251 females aged 13–19 years) were categorized based on maturity status: early (n = 98), average (n = 262), and late (n = 200), determined through Mirwald and colleagues’ equations. Anthropometric, physical fitness, and physiological data were collected for reference value creation. Our findings revealed significantly higher anthropometric parameters (p = 0.003) in late-maturing athletes compared to their early-maturing counterparts. Post-pubertal athletes showed significantly superior (p = 0.002) jumping ability, change of direction, and aerobic performance compared to their pre-pubertal peers. Additionally, male athletes outperformed females in both fitness (p = 0.001) and aerobic (p = 0.001) performance. A notable age-by-maturity interaction emerged for most performance outcomes (η2 ranging from 0.011 to 0.084), highlighting increased sex-specific differences as athletes progressed in age. Percentile values are provided for males and females, offering valuable insights for coaches and sports scientists to design personalized training programs. Understanding a player’s performance relative to these percentiles allows trainers to tailor workouts, addressing specific strengths and weaknesses for enhanced development and competitiveness

Unpublished Mediterranean records of marine alien and cryptogenic species

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta.JRC.D.2-Water and Marine Resource

Unpublished Mediterranean records of marine alien and cryptogenic species

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta.</p