Numerical study of flow stream in a mini VAWT with relative rotating blades

Today, wind energy is mainly used to generate electricity and more and more with a renewable energy source character. Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence and changes of wind direction. These conditions are not always optimal and have negative effects on most turbines. The present turbine is supposed to be less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’s one. Due to this combination of movements, flow around this turbine can be more optimized than classical Darrieus turbines. The turbine has a rotor with three straight blades of symmetrical aerofoil. Paper presents unsteady simulations that have been performed for one wind velocity and different blades stagger angles. The influence of two different blades geometry is studied for four different constant rotational speeds

Numerical study of flow stream in a mini VAWT with relative rotating blades

Today, wind energy is mainly used to generate electricity and more and more with a renewable energy source character. Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence and changes of wind direction. These conditions are not always optimal and have negative effects on most turbines. The present turbine is supposed to be less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’s one. Due to this combination of movements, flow around this turbine can be more optimized than classical Darrieus turbines. The turbine has a rotor with three straight blades of symmetrical aerofoil. Paper presents unsteady simulations that have been performed for one wind velocity and different blades stagger angles. The influence of two different blades geometry is studied for four different constant rotational speeds

Numerical simulation in vertical wind axis turbine with pitch controlled blades

Wind energy is more and more used as a renewable energy source character. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... The present turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be modeled by unsteady calculation. One of the main problems of such geometry is to simulate the two combined movements. The present work is an extended study of one’s made in 2009. In the previous study, some results like contours of pressure and velocity fields were presented for elliptic blades for one specific constant rotational speed and benefits of combined rotating blades was shown. The present paper points up the influence of two different blades geometries for different rotational speeds, different blade stagger angles and different Reynolds numbers related to a wider range of wind speeds

Posture-Cognitive Dual-Tasking: A Relevant Marker of Depression-Related Psychomotor Retardation. An Illustration of the Positive Impact of Repetitive Transcranial Magnetic Stimulation in Patients with Major Depressive Disorder

International audienceThis study examined whether postural control variables, particularly the center-of-pressure (COP) velocity-based parameters, could be a relevant hallmark of depression-related psychomotor retardation (PMR). We first aimed at investigating the interplay between the PMR scores and the COP performance in patients with major depressive disorder (MDD), as compared to age-matched healthy controls; secondly, we focused on the impact of a repetitive transcranial magnetic stimulation (rTMS) treatment on depression, PMR scores and postural performance. 16 MDD patients, and a control group of 16 healthy adults, were asked to maintain quiet standing balance during two trials with or without vision, and while backward counting (dual task). All the position and velocity-based COP variables were computed. Before and after the rTMS session (n eligible MDD~=~10), we assessed the depression level with the Montgomery-Asberg Depression Rating Scale (MADRS), the PMR scores with the French Retardation Rating Scale for Depression (ERD), and postural performance. Before the treatment, significant positive partial correlations were found between the pre-ERD scores and the velocity-based COP variables, especially in the dual-task conditions (p~<~0.05). In contrast, there was no significant correlation between the post-ERD scores and any postural parameter after the treatment. The MADRS and ERD scores showed a significant decrease between before and after the rTMS intervention. For the first time, the findings clearly validated the view that the assessment of postural performance - easy to envisage in clinical settings-constitutes a reliable and objective marker of PMR in MDD patients

Inégalités sociales dans la supplémentation prénatale en acide folique : résultats de la cohorte de naissance ELFE

International audienceIntroductionLa plupart des organisations professionnelles et nationales, y compris l'Organisation mondiale de la santé et, en France, la Haute Autorité de Santé, recommandent une supplémentation en acide folique pour les femmes en période périconceptionnelle (4 semaines avant la conception et 8 semaines après la conception). Les résultats de diverses études européennes ont montré des niveaux élevés de non-suivi de cette recommandation. L’objectif de la présente étude était d'identifier les caractéristiques sociodémographiques liées au suivi de la recommandation concernant la supplémentation en acide folique.MéthodesLes analyses ont reposé sur les données de 14 156 femmes de la cohorte de naissance nationale ELFE, collectées en 2011. Le moment de la supplémentation en acide folique a été évalué lors de l'entretien en face-à-face mené à la maternité et les caractéristiques sociodémographiques détaillées ont été recueillies après deux mois. L'association entre le respect de la recommandation sur la supplémentation en acide folique (pas de supplémentation ; supplémentation pendant la période périconceptionnelle : avant la conception ou durant les deux premiers mois de grossesse ; supplémentation seulement après la période périconceptionnelle) et les caractéristiques sociodémographiques a été étudiée en utilisant une régression logistique multinomiale.RésultatsSeulement 26% des femmes enceintes ont reçu une supplémentation en acide folique pendant la période périconceptionnelle, 10% pendant la grossesse mais après la période périconceptionnelle, et 64% des femmes n'ont reçu aucune supplémentation. Dans les analyses multivariées, un jeune âge maternel, un faible niveau d'études, un faible revenu familial, la multiparité, un surpoids maternel et un tabagisme maternel pendant la grossesse étaient associés à une plus faible probabilité de supplémentation en acide folique pendant la période périconceptionnelle (OR<25 ans vs. 25-29 ans=0,74 [0,67 ; 0,82] ; OR études primaires vs. BAC +5= 0,43 [0,35 ; 0,52] ; OR 4ème enfant vs. 1er enfant=0,41 [0,33 ; 0,51] ; OR obésité vs. poids normal =0,74 [0,65 ; 0,85] ; OR fumeuse toute la grossesse vs. non-fumeuse =0,71 [0,63 ; 0,79]). A l’inverse, les femmes qui ont arrêté de fumé juste avant leur grossesse avaient une probabilité plus élevée de recevoir une supplémentation en acide folique pendant la période périconceptionnelle (OR fumeuse avant grossesse vs. non-fumeuse =1,10 [1,01 ; 1,20]). Ces associations persistaient après exclusion des grossesses non planifiées. Les femmes immigrées et présentant une insuffisance pondérale étaient plus susceptibles de recevoir une supplémentation en acide folique uniquement après la période périconceptionnelle. (OR immigrée vs. née en France=1,33 [1,12 ; 1,57] ; OR insuffisance pondérale vs. poids normal= 1,30 [1,07 ; 1,58]).ConclusionsNotre étude confirme un faible suivi de la recommandation concernant la supplémentation en acide folique au cours de la période périconceptionnelle en France et de grandes disparités sociales dans le suivi de cette recommandation

Social Inequalities in Prenatal Folic Acid Supplementation: Results from the ELFE Cohort

Most professional and international organizations recommend folic acid supplementation for women planning pregnancy. Various studies have shown high levels of non-compliance with this recommendation. This study aimed to identify sociodemographic characteristics related to this compliance. The analyses were based on 16,809 women from the French nationwide ELFE cohort (Etude Longitudinale Fran&#231;aise depuis l&#8217;Enfance). Folic acid supplementation was assessed at delivery, and sociodemographic characteristics were collected at two months postpartum. The association between sociodemographic characteristics and compliance with recommendations on folic acid supplementation (no supplementation, periconceptional supplementation, and supplementation only after the periconceptional period) was examined using multivariate multinomial logistic regression. Only 26% of French women received folic acid supplementation during the periconceptional period, 10% of women received supplementation after the periconceptional period, and 64% received no supplementation. Young maternal age, low education level, low family income, multiparity, single parenthood, maternal unemployment, maternal overweight, and smoking during pregnancy were related to lower likelihood of folic acid supplementation during the periconceptional period compared to no supplementation. These associations were not explained by unplanned pregnancy. Immigrant and underweight women were more likely to receive folic acid supplementation after the periconceptional period. Our study confirms great social disparities in France regarding the compliance with the recommendations on folic acid supplementation