WorldWideScience

Sample records for dun entrainement par

  1. Commande d'un actionneur électrique par communication sans fil Zigbee

    OpenAIRE

    Llibre, Jean-François

    2010-01-01

    CNR IUT Angers 2010; Nous présentons ici un asservissement de position en sans fil d'un moteur à courant continu. La consigne élaborée au niveau d'un PC distant est envoyée via un module Zigbee à un autre module Zigbee, qui lui relié au moteur à commander, renvoie la mesure de la position. La commande numérique mise en œuvre doit être suffisamment robuste et la période d'échantillonnage judicieusement choisie pour s'affranchir des contraintes imposées par la communication hertzienne. Nous uti...

  2. Engine jet entrainment in the near field of an aircraft; Entrainement du jet d`un reacteur dans le champ aerodynamique proche d`un avion

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, F.; Jacquin, L.; Laverdant, A.

    1997-12-31

    A simplified approach has been applied to analyse the mixing and entrainment processes of the engine exhaust through their interaction with the vortex wake of an aircraft. Our investigation is focused on the near field, extending from exit nozzle to the beginning of the vortex phase (i.e. to about twenty seconds after the wake is generated). This study is performed using an integral model and a numerical simulation for a two engine large civil aircraft. The properties of the wing-tip vortices on the calculation of the dilution ratio (defined as a tracer concentration) have been shown. The mixing process is also affected by the buoyancy effect, but only after the jet regime, when the trapping in the vortex core has occurred. Qualitative comparison with contrail photography shows similar features. Finally the distortion and stretching of the plume streamlines inside the vortices can be observed, and the role of the descent of the vortices on the maximum tracer concentration has been discussed. (author) 19 refs.

  3. Ablation d'un film d'or par laser à excimère

    Science.gov (United States)

    Sentis, M.; Hermann, J.; Pereira, A.; Delaporte, Ph.; Marine, W.; Perrière, J.; Bianchi, L.; Galli, R.

    2003-06-01

    Ces travaux de recherche ont été réalisés dans le cadre du projet de développement du Laser MégaJoule (LMJ). Parmi les expériences d'interaction laser - matière à très haut flux, certaines conduiront à un dépôt de particules d'or sur les éléments internes de la chambre d'interaction. Pour nettoyer ce dépôt de particules, la possibilité d'utiliser un procédé automatisé basé sur l'ablation laser a été étudiée. Un modèle numérique simplifié a été développé et une étude expérimentale réalisée sur des échantillons d'acier inoxydable ou de B4C recouverts d'un film d'or d'une épaisseur de ~20 nm déposés par PVD. Ces travaux montrent que plus de 95 % du film d'or peuvent être enlevés avec quelques tirs d'un laser XeCI dès que la densité d'énergie dépasse 3 J/cm^2.

  4. Erythroblastopénie induite par la grossesse: à propos d'un cas et revue de la literature

    Science.gov (United States)

    Jihad, Drissi; Jaouad, Kouach; Driss, Moussaoui; Mohamed, Dehayni

    2016-01-01

    L’érythroblastopénie induite par la grossesse est une entité pathologique exceptionnelle dont seuls quelques cas isolés ont été décrits dans la littérature anglaise. L'objectif de ce travail est d'analyser les caractéristiques de cette pathologie extrêmement rare à travers la description d'un nouveau cas d’érythroblastopénie induite par la grossesse, et à travers l’étude des 17 cas antérieurement rapportés. PMID:27642487

  5. Optimisation du profil de dopage d'un MESFET réalisé par implantation ionique

    OpenAIRE

    Cazaux, J.L.; Graffeuil, Jacques; Pavlidis, D.

    1986-01-01

    On analyse l'interdépendance entre les performances d'un transistor à effet de champ en arséniure de gallium et son profil de dopage réalisé par implantation ionique. On étudie en particulier l'influence des conditions d'implantation (énergie et dose implantées) ainsi que celle du creusement de grille (« recess ») préalablement à la réalisation de la barrière Schottky. Les résùltats théoriques ont été obtenus à l'aide d'un simulateur permettant d'accéder aux propriétés statiques et dynamiques...

  6. Controle sismique d'un batiment en acier de 1 etage par amortisseurs elastomeres et contreventements en Chevron

    Science.gov (United States)

    Girard, Olivier

    Actuellement, le principe de dimensionnement a la capacite est fortement utilise dans le domaine du genie parasismique. De maniere simplifiee, cette methode de dimensionnement consiste a dissiper l'energie injectee a une structure lors d'une secousse sismique par la deformation inelastique d'un element structural sacrificiel. Cette methode de dimensionne-ment permet d'obtenir des structures economiques, car cette dissipation d'energie permet de reduire substantiellement les efforts qui se retrouvent a l'interieur de la structure. Or, la consequence de ce dimensionnement est la presence de degats importants a la structure qui suivent a la secousse sismique. Ces degats peuvent engendrer des couts superieurs aux couts d'erection de la structure. Bien entendu, sachant que les secousses sismiques d'importances sont des phenomenes rares, l'ingenieur est pret a accepter ce risque afin de diminuer les couts initiaux de construction. Malgre que cette methode ait permis d'obtenir des constructions economiques et securitaires, il serait interessant de developper un systeme qui permettrait d'obtenir des performances de controle des efforts sismiques comparables a un systeme dimensionne selon un principe de dimensionnement a la capacite sans les consequences negatives de ces systemes. En utilisant les principes d'isolation a la base, il a ete possible de developper un systeme de reprise des forces sismiques (SRFS). qui permet d'obtenir un controle des efforts sismiques concurrentiels tout en gardant une structure completement elastique. Ce systeme consiste u inserer un materiel elastomere entre l'assemblage de la poutre et des contreventements a l'interieur d'un cadre contrevente conventionnel. Cette insertion permet de diminuer substantiellement la rigidite laterale du batiment, ce qui a pour consequence d'augmenter la valeur de la periode fondamentale du batiment dans lequel ces cadres sont inseres. Ce phenomene est appele le saut de periode. Ce saut de periode permet de

  7. Conception, instrumentation, modelisation et analyse d'un element de stockage d'energie par chaleur latente

    Science.gov (United States)

    Millette, Jocelyn

    Des elements de stockage de chaleur utilisant l'electricite comme source d'energie sont utilises presentement en Europe ou la tarification de l'electricite varie en fonction du temps. Dans un contexte ou la dereglementation du marche de l'electricite s'opere massivement en Amerique du Nord, ce type d'appareil est susceptible d'etre beaucoup plus utilise afin de faire une gestion efficace de la consommation electrique. En assurant un meilleur facteur d'utilisation des installations de production, transport et distribution, les utilites pourront etre plus competitives. Les appareils disponibles sur le marche stockent l'energie sous forme sensible (ESECS), ce qui amene differents inconvenients: poids considerable, temperature elevee. Un nouveau type d'appareil est propose dans cette etude: un element de stockage d'energie par chaleur latente (ESECL). Cette etude traite donc de la conception de tels appareils. La demarche de conception proposee dans cette etude s'articule autour du choix des materiaux, du choix du concept de l'echangeur de chaleur. A ce sujet, les materiaux a changement de phase (MCP) etant generalement de mauvais conducteur thermique sous forme solide, la surface d'echange doit etre grande afin d'obtenir une puissance de destockage convenable. Le concept retenu est un element multicouches. D'apres la revue de litterature, la conception d'un element de stockage multicouches par chaleur latente n'a jamais ete abordee. Afin de pouvoir calculer les performances d'un ESECL a construire, un modele NTU-epsilon a ete developpe a cette fin. Contrairement. a ce qui est reporte dans la litterature, le modele developpe tient compte de la surchauffe et de la chaleur sensible dans le MCP solide. Afin d'etablir le modele, la convection naturelle dans le MCP liquide est negligee et un regime quasi permanent est considere dans le MCP. Un prototype d'ESECL a ete construit et instrumente dans le but d'eprouver la demarche de conception et de valider le modele developpe

  8. Conception et caracterisation d'un magnetoplasma produit par une onde de surface pour la pulverisation d'echantillons solides

    Science.gov (United States)

    Masse, Louis Philippe

    Suite a l'extraordinaire explosion de l'informatique de la derniere decennie, la science et la technologie des materiaux ont pris un essor extraordinaire. Par exemple, il est devenu crucial de concevoir des materiaux a haut degre de purete. Ce besoin a fortement motive le developpement de methodes d'analyse de solides. Traditionnellement, la methode adoptee est l'analyse par torche ICP, mais pour de nombreuses raisons, dont la lenteur de cette methode, la communaute scientifique oeuvrant en chimie analytique recherche des techniques d'analyse de solides directes, rapides et plus sensibles. Parmi les voies possibles, on trouve les methodes basees sur la pulverisation par plasma. Dans ce contexte, nous avons etudie la possibilite et la pertinence d'utiliser un magnetoplasma entretenu par une onde de surface pour pulveriser des solides dans le but de les analyser. Nos travaux portent principalement sur l'etude du comportement du plasma lors de la pulverisation. Nous avons montre que la pulverisation affecte la decharge de diverses facons. En premier lieu, la concentration d'especes provenant du materiau pulverise dans le plasma augmente avec la tension de polarisation. De plus, la concentration d'especes pulverisees diminue lorsque la pression croit, possiblement a cause du redepot. Nous avons aussi montre qu'il etait possible de pulveriser des solides isolants en exploitant le phenomene d'autopolarisation du a l'application d'une tension RF. Nous avons aussi etudie l'effet de la pulverisation sur la temperature et la densite electronique. Ainsi, lors de la pulverisation de metaux tels que le cuivre, la temperature electronique diminue lorsque la tension de polarisation augmente. Ceci est attribuable a l'augmentation de la densite d'especes metalliques neutres facilement ionisables par impact electronique. Nous avons aussi note que la densite electronique augmente avec la concentration d'especes metalliques dans le plasma, ce qui resulte d'un meilleur bilan de

  9. Proprietés mécaniques de surface d'un acier inoxydable traité par explosif

    Science.gov (United States)

    Paillé, L.; Gerland, M.; Villain, J. P.; Badawi, K. F.; Presles, H. N.; Bouchet, B.

    1994-02-01

    A new surface treatment technique by primary explosive was used on a 316L type austenitic stainless steel. Two explosive compositions, inducing a pressure of 1 GPa and 4 GPa respectively, were deposited in a thin layer on plane samples. The detonation induced effects have been characterized by different techniques. The surface roughness increases with the applied pressure, but remains lower than that obtained after shot peening. The microbardness profiles along a direction perpendicular to the treated surface and the microstructural study exhibit a marked hardening on several hundred micrometers associated with a profuse twinning. Moreover, for the 4 GPa pressure a very thin surface layer of fine recrystallized grains appears. In both cases, tensile residual stresses are measured at the surface and compressive stresses beyond 10~μm. The microstructure in the surface layers results of a noticeable thermal effect. The wear resistance of this stainless steel is improved by a factor 10 to 200 depending on the treatment conditions. Une technique de traitement de surface utilisant un explosif primaire a été utilisée sur un acier inoxydable austénitique de type 316L. Deux compositions explosives délivrant des pressions respectives de 1 GPa et 4 GPa ont été déposées en couche mince sur des échantillons plans. Les effets induits par la détonation ont été caractérisés par différentes techniques. La rugosité en surface augmente avec la pression appliquée mais reste très inférieure à celle obtenue après grenaillage. Les profils de microdureté suivant un axe perpendiculaire à la surface traitée et l'étude microstructurale montrent un écrouissage marqué sur quelques centaines de micromètres associé à un maclage important auquel s'ajoute, pour la pression de 4 GPa, une fine recristallisation en surface. Dans les deux cas, les contraintes résiduelles sont de tension en surface et passent en compression au-delà de 10~μm. La microstructure des

  10. Refroidissement par évaporation d'un jet atomique guidé magnétiquement

    Science.gov (United States)

    Lahaye, T.

    2006-01-01

    This work deals with the experimental realization of an ultracold, magnetically guided atomic beam in the collisional regime. After a detailed description of the experimental setup developed for this purpose, a method to measure the beam temperature with radio-frequency spectroscopy is proposed theoretically and demonstrated experimentally. The variations in temperature, phase-space density and elastic collision rate of the beam during a cycle evaporation-rethermalization are calculated. Two-antenna radio-frequency evaporation experiments are then described. They allow one to demonstrate the occurrence of elastic collisions within the atomic beam. Two Hamiltonian methods allowing one to increase the elastic collision rate are then studied theoretically and investigated experimentally. The gain in the elastic collision rate obtained this way is then used in order to cool the beam by means of ten evaporation zones, thus increasing the beam's phase-space density by one order of magnitude. Finally, a detailed theoretical study of the evaporation kinetics shows that a ten-fold increase of the collision rate obtained so far should be sufficient to achieve quantum degeneracy. Cet ouvrage traite de la réalisation expérimentale d'un jet atomique ultrafroid guidé magnétiquement, dans le régime collisionnel. Après une description détaillée du dispositif expérimental développé à cette fin, une méthode de thermométrie par spectroscopie radio-fréquence est proposée et démontrée expérimentalement. Les variations de température, densité dans l'espace des phases et taux de collisions élastiques du jet au cours d'un cycle évaporation-rethermalisation sont calculées. Des expériences d'évaporation radio-fréquence à deux antennes sont ensuite présentées, qui permettent de prouver l'existence de collisions au sein du jet. Deux méthodes permettant d'augmenter le taux de collisions sont ensuite étudiées théoriquement, puis mises en œuvre. Le gain en taux

  11. High G Physiological Protection Training (Acceleratio;s Elevees: Protection par l’Entrainement)

    Science.gov (United States)

    1990-12-01

    1’origine d’un certain nombre de pertes, de connaissance (PC-G en- anglais G-Loc ou G induced Loss of Consciousness). Lorsque l’avion n’a Pu &re...25 et 26 avril 1985 (Compte-rendu de la conference de I’AGARD no 396). La question de l’entrainement h la protection anti-G y a 6t6 examinie. Au cours ...accept6 la creation de ce groupe de travail au cours de la 62ýme rdunion qui a eu lieu a Paris, France, les 26 et 27 mars 1987. Le groupe de travail no 14

  12. Conséquences d'un traumatisme par brûlure sur le comportement social de l'enfant et de l'adolescent

    OpenAIRE

    Bourgeois, Sandra; Wurlod, Olivia; Pichonnaz, Claude; Jaccard, Hervé

    2014-01-01

    Introduction : L’accident par brûlure constitue, chez l’enfant, la troisième cause de traumatisme physique après les chutes et les coupures. Il représente une véritable épreuve pour l’enfant car il entraine des séquelles esthétiques, fonctionnelles et psychologiques. Problématique : Le changement d’apparence physique ainsi que toutes les contraintes engendrées par la prise en charge de la brûlure peuvent constituer un obstacle aux relations interpersonnelles et induire des troubles du comport...

  13. Modelisation numerique et validation experimentale d'un systeme de protection contre le givre par elements piezoelectriques

    Science.gov (United States)

    Harvey, Derek

    Le degivrage au moyen d'actuateurs piezoelectriques est considere comme une avenue prometteuse pour le developpement de systemes a faible consommation d'energie applicables aux helicopteres legers. Ce type de systeme excite des frequences de resonances d'une structure pour produire des deformations suffisantes pour rompre l'adherence de la glace. Par contre, la conception de tel systeme demeure generalement mal comprise. Ce projet de maitrise etudie l'utilisation de methodes numeriques pour assister la conception des systemes de protection contre le givre a base d'elements piezoelectriques. La methodologie retenue pour ce projet a ete de modeliser differentes structures simples et de simuler l'excitation harmonique des frequences de resonance au moyen d'actuateurs piezoelectriques. Le calcul des frequences de resonances ainsi que la simulation de leur excitation a ensuite ete validee a l'aide de montages experimentaux. La procedure a ete realisee pour une poutre en porte-a-faux et pour une plaque plane a l'aide du logiciel de calcul par elements finis, Abaqus. De plus, le modele de la plaque plane a ete utilise afin de realiser une etude parametrique portant sur le positionnement des actuateurs, l'effet de la rigidite ainsi que de l'epaisseur de la plaque. Finalement, la plaque plane a ete degivree en chambre climatique. Des cas de degivrage ont ete simules numeriquement afin d'etudier la possibilite d'utiliser un critere base sur la deformation pour predire le succes du systeme. La validation experimentale a confirme la capacite du logiciel a calculer precisement a la fois les frequences et les modes de resonance d'une structure et a simuler leur excitation par des actuateurs piezoelectriques. L'etude revele que la definition de l'amortissement dans le modele numerique est essentiel pour l'obtention de resultats precis. Les resultats de l'etude parametrique ont demontre l'importance de minimiser l'epaisseur et la rigidite afin de reduire la valeur des frequences

  14. 5 W à 255 nm et 15 kHz obtenus par doublage defréquence d'un laser CuHBr dans du BBO

    Science.gov (United States)

    Huot, N.; Jonin, C.; Le Harzic, R.; Audouard, E.; Laporte, P.

    2003-06-01

    5.1 W de rayonnement ultra-violet ont été obtenus à 15 kHz par doublage de fréquence de la raie à 510.6 nm d'un laser CuHBr dans deux cristaux de BBO. La qualité de faisceau du rayonnement UV est exprimée par le paramètre M^2 : M_X^2 = 30± 2 et M_Y^2= 24 ± 2. Les deux faisceaux UV issus des deux cristaux de BBO, combinés au point focal d'une lentille, permettent le micro-usinage UV à haute cadence.

  15. Détermination en tridimensionnel des pertes par courant de Foucault dans la cuve d'un transformateur

    Science.gov (United States)

    Guérin, Christophe; Tanneau, Gérard; Meunier, Gérard; Sakellaris, Ioannis

    1993-03-01

    This paper deals with 3D electromagnetic modelling of a transformer so as to evaluate eddy current losses in the tank. In this purpose, several numerical methods have been used with two 3D softwares, FLUX3D (LEG) and TRIFOU (EDF). These methods use either nodal finite elements with the magnetic vector potential (FLUX3D), or the edge finite elements with the magnetic field as the state variable (TRIFOU). Classical volume elements and several special elements have been used : shell elements with the magnetic vector potential for the modelling of thin conducting regions, and surface elements for conducting regions with a small skin depth. The results given by these methods with several characteristics of the tank and magnetic core have been compared and their validity domain has been verified. The shell elements suit well when the skin depth is larger than the tank thickness, whereas in the opposite case, the surface elements for thin skin depth regions are well adapted. Nous présentons la modélisation tridimensionnelle d'un transformateur pour la détermination des pertes par courants de Foucault dans sa cuve. Pour cela, plusieurs méthodes numériques ont été utilisées à l'aide de deux codes de calcul tridimensionnels : FLUX3D (LEG) et TRIFOU (EDF). Ces méthodes utilisent soit les éléments finis nodaux avec le potentiel vecteur magnétique (FLUX3D), soit les éléments finis d'arête avec le champ magnétique comme variable d'état (TRIFOU). Outre l'utilisation des éléments volumiques, nous avons employé des éléments surfaciques de type coque en potentiel vecteur magnétique pour la modélisation de regions conductrices minces, ainsi que des éléments surfaciques pour les régions conductrices présentant une faible épaisseur de peau. Les résultats obtenus avec ces méthodes pour différentes caractéristiques du matériau de la cuve et du circuit magnétique ont permis de vérifier leur domaine de validité. Les éléments de type coque conviennent

  16. Modèle de comportement dynamique d'un matériau en présence de l'endommagement par cisaillement adiabatique

    Science.gov (United States)

    Longère, P.; Dragon, A.; Trumel, H.; de Resseguier, T.; Deprince, X.; Petitpas, E.

    2002-12-01

    L'objectif industriel du travail dans lequel s'inscrit ce papier est la simulation numérique de la réponse de structures à l'impact. Or, pour un grand nombre de matériaux métalliques à haute résistance soumis à des sollicitations à grande vitesse, le cisaillement adiabatique constitue un processus endommageant conduisant souvent à la ruine par macrofissuration. Nous présentons ici un modèle continu qui, construit sur des bases thermodynamiques, rend compte du comportement thermo-élasto/viscoplastique du matériau sain et de l'anisotropie mécanique (dégradation directionnelle des modules élastiques et viscoplastiques induite par la présence des bandes de cisaillement adiabatique dans le matériau endommagé. Dans notre démarche de modélisation qui tend à refléter les constats expérimentaux, la population de bandes est représentée par une variable tensorielle d'endommagement au sein d'un matériau homogène équivalent. Le modèle est formulé dans le cadre des transformations finies élasto-plastiques avec prise en compte de l'anisotropie induite. Sa particularisation au cas des petites perturbations est illustrée pour certains processus homogènes.

  17. Modélisation multi-physique couplée d'un procédé de traitement thermique par induction

    OpenAIRE

    Cardinaux, David; Bay, François; Chastel, Yvan; Feraille, Julien

    2009-01-01

    http://hdl.handle.net/2042/36901; International audience; L'étude s'applique à la trempe après chauffage par induction localisé d'une tôle emboutie. Le procédé génère des distorsions dans la structure qui sont à maîtriser. Un outil de calcul numérique tenant compte des couplages multi-physiques entre électromagnétisme, thermique, mécanique et métallurgie est alors nécessaire. La création d'un tel outil utilisant la méthode des éléments finis est le but de ce travail.

  18. Conception et calibration d'un sonoreacteur pour l'oxydation de la cellulose par le systeme TEMPO/NaOCl/NaBr

    Science.gov (United States)

    Paquin, Michel

    grande consommation d'energie et de reactif qui rend le procede difficilement accessible au milieu industriel. L'utilisation des ultrasons lors de la reaction d'oxydation permet de reduire de 50% le temps de reaction et d'autant la consommation de produits chimiques. Actuellement le processus d'oxydation s'effectue en mode discontinu pour une quantite de 20 grammes de pate dans un reacteur en verre dans un bain a ultrason. L'objectif principal de ce travail est d'elaborer un sonoreacteur en mode semi-continu afin d'etre en mesure de transferer une reaction d'oxydation du mode discontinu en mode semi-continu. Le transfert de reaction sera effectue en realisant la calibration de l'activite acoustique des deux differents reacteurs, discontinu et semi-continu, par la methode de Weissler. La methode de Weissler quantifie le taux de production radicalaire en mesurant la formation d'iode moleculaire d'une solution aqueuse d'iodure de potassium sous ultrason. Suite a sa calibration, le sonoreacteur pilote (mode semi-continu) a demontre une augmentation de la production radicalaire de 683 % a 170 kHz en comparaison avec l'utilisation d'un bain a ultrason a la meme frequence. Lors de la reaction d'oxydation, la puissance optimale utilisee dans le bain a ultrason a 170 kHz est de 1000 W. La puissance utilisee selon les resultats de calibration obtenue dans le sonoreacteur pilote est de 125 W soit une diminution de l'energie appliquee de 87,5 %. Lors de la reaction d'oxydation, le taux de production des groupements carboxylates est de 2,6 mmol COOH kg/min dans le bain a ultrason et de 6,87 mmol COOH kg/min dans le sonoreacteur pilote soit une augmentation de 164% du taux de formation. Selon les resultats obtenus, l'utilisation d'un sonoreacteur en mode continu peut etre envisageable pour la reaction d'oxydation de la cellulose par le systeme TEMPO-NaOCl-NaBr en industrie au niveau industriel.

  19. Démarche pour le choix et/ou la conception d'un moyen de soudage par FSW

    OpenAIRE

    ZIMMER-CHEVRET, Sandra; LANGLOIS, Laurent; LAYE, Julien; Goussain, Jean-Claude; Martin, Patrick; Bigot, Régis

    2009-01-01

    National audience; Les travaux de recherches présentés concernent l'industrialisation du procédé de soudage par friction malaxage, également appelé Friction Stir Welding (FSW). L'objectif est de fournir des outils aux industriels pour choisir et qualifier une machine pour leurs applications de FSW. Cet article présente une méthodologie pour qualifier et / ou concevoir les moyens de soudage adaptés à une application donnée. La démarche de qualification repose sur l'étude géométrique des pièces...

  20. Structure par RMN d'un complexe AlcR(1-60)-ADN: Reconnaissance du petit sillon par la partie N-terminale

    Science.gov (United States)

    Cahuzac, B.; Félenbok, B.; Guittet, E.

    1999-10-01

    Aspergillus nidulans is a filamentous fungus able to use ethanol as sole energy source. The activation of the ethanol regulon genes expression is mediated by the AlcR protein. Its DNA-binding domain is located in the N-terminus (residues 1 to 60), and its NMR solution structure shows a global zinc binuclear cluster fold, with two helices in addition to the basic binuclear motif. A small number of crystallographic structures of DNA complexes of binuclear cluster proteins is yet known, and points out the major groove and the first helix as the principal sites of interaction on the DNA and the protein respectively. In this article we show evidences that the N-terminus of the protein is involved in binding to the minor groove. Aspergillus nidulans est un champignon filamenteux capable d'utiliser l'éthanol comme source unique d'énergie. La protéine AlcR est responsable de l'activation de l'expression des gènes du régulon éthanol. Le domaine de liaison à l'ADN est situé dans la partie N-terminale de la protéine (a.a. 1 à 60), et sa structure déterminée par RMN en solution montre un repliement global en bouquet binucléaire à zinc, avec deux hélices supplémentaires par rapport au motif de base. Alors que les structures déjà connues de complexes ADN - bouquets binucléaires permettent de situer dans le grand sillon la quasi-totalité des interactions, nous montrons dans la présente étude l'implication du début de la séquence dans la reconnaissance du petit sillon de l'ADN (a.a. 5 et 6).

  1. Étude d'un filtre de neutrons épithermiques pour la thérapie par capture de neutrons : validation expérimentale de la simulation Monte Carlo

    Science.gov (United States)

    Colomb, F.; Ermont, G.

    1998-04-01

    A part of Neutron Capture Therapy research bears on epithermal neutron beam design. This paper relates to the project of an epithermal neutron filter designed for the experimental reactor ISIS. This filter allows neutron energy spectrum adaptation to the tumor depth. The Monte Carlo code TRIPOLI 3 was used to simulate the filter response. The results from Monte Carlo simulations are compared to experimental results of neutrons spectra. Une partie de la recherche sur la Thérapie par Capture de Neutrons est consacrée à l'optimisation des faisceaux pour obtenir des neutrons d'énergie adaptée en fonction de la profondeur de la tumeur. Le but du projet décrit dans cette communication est la construction d'un filtre adaptable au réacteur de recherche ISIS. Une étude a été menée sur un dispositif préliminaire appelé “manchette" qui servira de support à divers écrans. Cette communication présente une comparaison des spectres obtenus par la simulation Monte Carlo et ceux obtenus expérimentalement à partir de détecteurs d'activation aux extrémités du dispositif.

  2. Étude micromécanique de la disparition du seuil de fissuration par fatigue d'un alliage de titane biphasé à fort K_{max}

    Science.gov (United States)

    Mignot, F.; Doquet, V.; Sarrazin-Baudoux, C.; Petit, J.

    2003-03-01

    L'alliage Ti6246 présente, lors d'essais de fissuration par fatigue à K_{max} constant et ΔK décroissant un comportement atypique : lorsque K_{max}ge 0.7KIC, on observe, sous air comme sous vide, au lieu du seuil attendu, un régime de propagation à vitesse constante, dix fois plus élevée à l'ambiante qu'à 500^{circ}C. Le fluage, qui se manifeste dès l'ambiante dans cet alliage semble jouer un rôle dans ce phénomène. Toutefois, des analyses par spectrométrie de masse d'ions secondaires font apparaître une sur-concentration en hydrogène au voisinage d'une fissure développée dans le régime anormal. Des essais de fissuration, traction et fluage sont donc entrepris sur le matériau brut, appauvri ou enrichi en hydrogène, pour partie dans la chambre d'un microscope électronique à balayage, dans le but d'explorer ce phénomène. On constate qu'un enrichissement en hydrogène augmente la ductilité du matériau et sa tendance au fluage à l'ambiante et un enrichissement plus prononcé la diminue.

  3. Pseudo-HELLP syndrome par carence en folates et/ou en vitamine B12: à propos d'un cas

    Science.gov (United States)

    Benali, Mechaal; Bouassida, Mahdi; Dhouib, Firas; Bouzeidi, Kaled

    2014-01-01

    Plusieurs pathologies médicales peuvent interférer avec la grossesse et mimer le tableau biologique de HELLP syndrome. L’évolution naturelle de ce syndrome est d'une particulière gravité pour la mère et le fœtus, il convient d’éliminer rapidement les autres diagnostics afin d’éviter une extraction fœtale prématurée injustifiée. Nous rapportons le cas d'une parturiente qui s'est présentée avec un tableau évocateur d'un HELLP syndrome, rapporté finalement à une carence en folates et en vitamine B12. PMID:25404961

  4. Particle re-entrainment from a powder deposit in an horizontal air flow; Mise en suspension d'une contamination particulaire par ecoulement d'air

    Energy Technology Data Exchange (ETDEWEB)

    Alloul, L.; Witschger, O. [CEA/Saclay, Inst. de Protection et de Surete Nucleaire, IPSN/DPEA/SERAC, Lab. de Physique et Metrologie des Aerosols et du Confinement, 91 - Gif-sur-Yvette (France); Renoux, A. [Paris-12 Univ., Lab. de Physique des Aerosols et de Transfert des Contaminations, 94 - Creteil (France); Le Dur, D. [Aerolab, 91 - Courtaboeuf (France); Monnatte, J. [COGEMA, Branche Combustible et Recyclage, Service Qualite Surete, 78 - Saint-Quentin-en-Yvelines (France)

    2000-07-01

    Particle re-entrainment from surfaces to turbulent air flow is an important subject in many different fields like nuclear safety, environmental air pollution, sediment transport by wind, surface contamination in semiconductor operations. Theoretical and experimental studies have been numerous and cover different aspects of the phenomena. Although a number of theoretical works have been devoted for describing the mechanisms of detachment of primary spherical particles form flat smooth surfaces in a turbulent flow, experimental data are still needed in order to comparison. Moreover, the knowledge of the effect of parameters related to the deposit (monolayer, multilayer, cone-like pile), the powder particles (particle-size distribution, adhesive properties), the surface (roughness,...),the airflow (velocity, acceleration, turbulence) or the environment (humidity,...) is still in an elementary stage. The main objective of our work is to contribute to the understanding and quantification of the parameters that govern the particle re-entrainment from a powder deposit in an turbulent horizontal airflow. Therefore, a new experimental facility called BISE (french acronym for wind tunnel for studying particle re-entrainment by airflow) has been designed and built in our laboratory. (authors)

  5. Disseny i implementació d'un sistema intel.ligent per a la mesura de paràmetres ambientals

    OpenAIRE

    Font Rius, Adrià

    2008-01-01

    L’objectiu d’aquest treball és dissenyar un sistema intel•ligent que permeti controlar la mesura de paràmetres ambientals. Per fer-ho utilitzarem un microcontrolador que elegirem segons les característiques com memòria o velocitat de càlcul. Un cop programat, el microcontrolador haurà de ser capaç d’ajustar dades experimentals a un model i obtenir una sèrie de paràmetres d’interès. S’ha implementat un algorisme d’ajust tipus Levenberg-Marquardt en un microcontrolador PIC i s...

  6. Calcul de l'impédance d'un inducteur circulaire plat par conjonction des méthodes intégrales de frontière et éléments finis

    Science.gov (United States)

    Fouladgar, J.; Develey, G.

    1992-11-01

    The knowledge of the impedance of the whole inductor-load has a great importance for the design of the generators used in the induction heating technology. In this paper, we study the case of a plannar circular inductor fed by a voltage u of a variable frequency up to 30 kHz. To calculate the impedance, one should resolve the diffusion equation in a axisymetric configuration. Here we propose a mixed method, using the finit elements method in the volume of the inductor and load and a boundary elements method at their surfaces. La connaissance de l'impédance de l'ensemble inducteur-charge revêt une grande importance pour la conception des générateurs utilisés dans la technique du chauffage par induction. Dans cet article, nous étudions le cas d'un inducteur plat circulaire alimenté sous une tension fixe u, de fréquence variable jusqu'à 30 kHz. Le calcul de l'impédance passe par la résolution de l'équation de diffusion dans un système axisymétrique. Nous proposons ici une méthode mixte utilisant la méthode d'éléments finis dans le volume de la charge et de l'inducteur et la méthode d'intégrales de frontière à leur surface.

  7. Analyse quantitative de la fraction PI - C20 de pétrole par couplage d'un chromatographe en phase gazeuse et d'un spectromètre de masse Quantitative Analysis of the Ibp - C20 Fraction of Oil by Gc/Ms Coupling

    Directory of Open Access Journals (Sweden)

    Castex H.

    2006-11-01

    Full Text Available Une méthode d'analyse quantitative par couplage CG/SM sur une colonne remplie a été développée. Elle opère à moyenne résolution, triant ainsi les masses exactes d'hydrocarbures saturés, aromatiques et soufrés. Axée sur l'obtention d'un spectre moyen de fractions bien définies en carbone, elle utilise des matrices de coefficients disponibles dans la littérature et restitue une répartition détaillée en familles d'hydrocarbures dont les applications décrites sont intéressantes. La méthode satisfait à plusieurs objectifs : elle évite une distillation et une séparation par chromatographie liquide et elle permet de travailler sur de très petites quantités de produit avec un coût opératoire réduit. A quantitative analysis method has been developed by coupling GC/MS with a packed column. It operates at medium resolution, sorting out the exact masses of saturated, aromatic and sulfur-containing hydrocarbons. Based on the obtaining of an average spectrum of well-defined carbon fractions, this method uses coefficient matrices available in the literature and plots a detailed hydrocarbon distribution for which the applications described are interesting. The method fulfills several aims. It makes a distillation and separation by liquid chromatography unnecessary. It can be used with very small quantities of product, with a reduced operating cost.

  8. Navigation d'un vehicule autonome autour d'un asteroide

    Science.gov (United States)

    Dionne, Karine

    resultats de simulation montrent que l'ajout d'une mesure de distance par cycle de mise a jour entraine une amelioration significative des performances de navigation. Ce procede reduit l'erreur d'estimation ainsi que les periodes de non-observabilite en plus de contrer la dilution de precision des mesures. Les analyses de sensibilite confirment quant a elles la contribution des mesures de distance a la diminution globale de l'erreur d'estimation et ce pour une large gamme de parametres de conception. Elles indiquent egalement que l'erreur de cartographie est un parametre critique pour les performances du systeme de navigation developpe. Mots cles : Estimation d'etat, filtre de Kalman adaptatif, navigation optique, lidar, asteroide, simulations numeriques

  9. A fly-wheel drive with controlled-torque clutch for a reactors cooling circuit pumps; Entrainement des pompes du circuit de refrigeration d'un reacteur par volant a embrayage sous couple controle

    Energy Technology Data Exchange (ETDEWEB)

    Riettini, A. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-10-15

    After a theoretical study on the slowing down of a centrifugal pump, the motion equations have been checked by means of experimental tests. In order to have important slowing down times (which is the case of the cooling pumps of a research reactor) it is necessary to add a fly-wheel. To prevent troubles when starting, a block pump-fly-wheel with clutch under controlled torque was developed. It is so possible to start the fly-wheel progressively without increasing too much power of the driving motor. (author) [French] Apres une etude theorique sur le mouvement de ralentissement d'une pompe centrifuge, les equations du mouvement ont ete verifiees par des essais pratiques. Pour obtenir des temps de ralentissement importants (cas des pompes de refrigeration d'un reacteur de recherche) il est necessaire d'y adjoindre un volant d'inertie. Pour eviter les inconvenients au demarrage, on a etudie un ensemble pompe-volant avec embrayage sous couple controle. Cette solution permet de lancer progressivement le volant sans augmentation appreciable de la puissance du moteur d'entrainement. (auteur)

  10. Sources d'hétérogénéité d'un assemblage par soudage par diffusion homogène de tôles en acier austénitique inoxydable Heterogeneity sources during homogeneous HIP-bonding of austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Bouquet Nicolas

    2013-11-01

    Full Text Available Ce document présente un aperçu des hétérogénéités de microstructure aux interfaces qui peuvent être rencontrées lors du soudage par diffusion homogène d'un assemblage de tôles. Un assemblage homogène a finalement été réalisé avec l'obtention de propriétés mécaniques très satisfaisantes. Pour finir, une piste de réflexion est apportée afin d'améliorer les propriétés des assemblages. This document deals with the structural sources of heterogeneity during homogeneous HIP-bonding of austenitic stainless steel. An homogeneous microstructure was finally obtained with very good mechanical properties comparable to those of the base material. To conclude, a way to further improve the assembly properties is discussed.

  11. Décision d'amputation dans la prise en charge initiale d'une luxation ouverte grave de la cheville à propos d'un cas observé à l'Hôpital Laquintinie de Douala suite à un accident par moto-taxi

    OpenAIRE

    Tsatedem, Faustin Atemkeng; Tsiagadigui, Jean Gustave; Ndando, Richard Polle; Arabo, Mohamadou Saidou; Bayiha, Alphonse; Kenfack, Bruno

    2012-01-01

    La décision d'amputation pour traumatisme grave de membre n'est pas toujours facile à prendre. Les auteurs rapportent le cas d'un traumatisme ouvert de la cheville gauche avec luxation tibiotalienne complète, référé pour amputation. Il s'agit d'une passagère d'une moto-taxi percutée par une voiture. A l'admission, le pouls tibial postérieur était présent et le score dit MESS (Mangled Extremity Severity Score) côté à 5, ce qui a permis et d'éviter l'amputation. Après débridement et réduction, ...

  12. The art of entrainment

    OpenAIRE

    Roenneberg, T.; Daan, S; Merrow, M.

    2003-01-01

    The circadian system actively synchronizes the temporal sequence of biological functions with the environment. The oscillatory behavior of the system ensures that entrainment is not passive or driven and therefore allows for great plasticity and adaptive potential. With the tools at hand, we now can concentrate on the most important circadian question: How is the complex task of entrainment achieved by anatomical, cellular, and molecular components? Understanding entrainment is equal to under...

  13. Activité nycthémérale et utilisation de la séquence radier-profond par les truitelles d'un an (Salmo trutta L.

    Directory of Open Access Journals (Sweden)

    ROUSSEL J. M.

    1995-04-01

    Full Text Available Le comportement d'un groupe de dix truitelles d'un an (Salmo trutta L. a été étudié au cours de deux cycles d'observation de 3 jours dans une séquence radier-profond reconstituée en milieu semi-naturel. Des changements de préférences d'habitat ont été mis en évidence à l'échelle du nycthémère et correspondent à des changements d'activité (repos, nage et alimentation. Lorsqu'elles sont en nage statique et en alimentation sur la dérive, les truitelles défendent leur poste et occupent le radier et le profond en pleine eau. Au repos, elles sont posées sur le fond du contre-courant et du profond, et elles n'exhibent pas de comportement agonistique. De plus, les truitelles ont montré un rythme d'activité diurne prononcé.

  14. Etude simulée d'un système de dessalement d'eau de mer et de production de froid par thermofrigopompe couplée à des panneaux solaires

    OpenAIRE

    Byrne, Paul; Miriel, Jacques; Serres, Laurent; Ghoubali, Redouane

    2012-01-01

    International audience; L'accès à l'eau potable est un des enjeux majeurs des prochaines decennies. La recherche sur les technologies de dessalement à forte efficacité énergétique doit donc être particulièrement active. Cet article présente un système de thermofrigopompe produisant simultanément du froid pour une enceinte réfrigérée et de la chaleur utilisée par une unité de dessalement par distillation membranaire. L'énergie électrique est fournie par des panneaux photovoltaïques pour une po...

  15. Décision d'amputation dans la prise en charge initiale d'une luxation ouverte grave de la cheville à propos d'un cas observé à l'Hôpital Laquintinie de Douala suite à un accident par moto-taxi

    Science.gov (United States)

    Tsatedem, Faustin Atemkeng; Tsiagadigui, Jean Gustave; Ndando, Richard Polle; Arabo, Mohamadou Saidou; Bayiha, Alphonse; Kenfack, Bruno

    2012-01-01

    La décision d'amputation pour traumatisme grave de membre n'est pas toujours facile à prendre. Les auteurs rapportent le cas d'un traumatisme ouvert de la cheville gauche avec luxation tibiotalienne complète, référé pour amputation. Il s'agit d'une passagère d'une moto-taxi percutée par une voiture. A l'admission, le pouls tibial postérieur était présent et le score dit MESS (Mangled Extremity Severity Score) côté à 5, ce qui a permis et d'éviter l'amputation. Après débridement et réduction, une broche transplantaire a permis d'immobiliser la cheville et de faire les pansements. L'amputation a été évitée. La cicatrisation dirigée de la peau a été suivie par la kinésithérapie. La mobilité de la cheville autorise une marche avec cannes au quatrième mois post-opératoire. Les auteurs recommandent l'utilisation du MESS dans la décision d'amputation après traumatisme grave de membre. PMID:23396997

  16. Validation d'un formalisme cinétique par optimisation de paramètres : approche et méthode mathématiques Validation of a Kinetic Formalization by Means of Parameter Optimization: Approach and Mathematical Method

    Directory of Open Access Journals (Sweden)

    Alario F.

    2006-12-01

    Full Text Available Cet article est une synthèse du travail fait en commun entre la Division Informatique et Mathématiques Appliquées DIMAet la division Cinétique et Catalyse de l'Institut Français du Pétrole. On y expose une nouvelle approche mathématique pour la validation d'un formalisme cinétique : la déshydrocyclisation du n-heptane. This article is an overview of the work carried out together by the DIMAand the Cinétique et Catalysedivision of the Institut Français du Pétrole. It is a new mathematical approach to validate a kinetic formalization : the n-heptane dehydrocyclization.

  17. Amélioration du rendement d'un onduleur à Z-source par une stratégie d'adaptation de sa tension du bus continu.

    OpenAIRE

    BATTISTON, Alexandre

    2014-01-01

    International audience; Cet article propose une méthode de contrôle visant à adapter la tension de bus continu d'un système de traction électrique utilisant un onduleur à source impédante (Z-source) et alimentant une machine synchrone à aimants. L'objectif de la commande proposée consiste en l'amélioration du rendement global du système en réduisant le surdimensionnement de la référence de tension du bus continu. Elle est ainsi adaptée continument à la demande en puissance du moteur. Une comm...

  18. Identification optimale des paramètres d'un système dynamique régi par une équation différentielle stochastique linéaire commandée

    OpenAIRE

    Brahimi, Nadia

    1985-01-01

    Université : Université scientifique et médicale de Grenoble; L'étude consiste à estimer des paramètres pour un système dynamique régi par une équation différentielle stochastique, linéaire, unidimensionnelle, excitée par des bruits brownien et poissonnien, en présence de contrôles adaptés à l'état du système. On suppose que les paramètres des bruits sont connus, et on montre que l'on peut estimer les paramètres de dérive par une famille, convergente et asymptotiquement normale, d'estimateurs...

  19. Constraints on Spontaneous Entrainment

    Directory of Open Access Journals (Sweden)

    Richardson Michael J.

    2011-12-01

    Full Text Available Past research has revealed that a person's rhythmic limb movements become spontaneously entrained to an environmental rhythm if a. visual information about the environmental rhythm is available and b. its frequency of the environmental rhythm is near that of the person's movements. Further, this research has demonstrated that if the eyes track the environmental stimulus, the spontaneous entrainment to the environmental rhythm is strengthened. Experiments were performed to investigate two hypotheses that could explain this eye-tracking enhancement of spontaneous entrainment. One hypothesis is that eye tracking allows for the pick up of important coordinative information at the turn-around points of a movement trajectory. Another hypothesis is that the limb movements entrain to the moving eyes through a neuromotor synergy linking the eyes and limb. Results of these experiments will help delineate the informational and dynamical constraints that can impact the acquisition of skilled actions.

  20. Microscopie par rayons X dans la fenêtre de l'eau : faisabilité et intérêt pour la biologie d'un instrument de laboratoire

    Science.gov (United States)

    Adam, J. F.; Moy, J. P.

    2005-06-01

    La biologie étudie des structures ou des phénomènes sub-cellulaires. Pour cela la microscopie est la technique d'observation privilégiée. La résolution spatiale de la microscopie optique s'avère bien souvent insuffisante pour de telles observations. Les techniques plus résolvantes, comme la microscopie électronique par transmission sont souvent destructrices et d'une complexité peu adaptée aux besoins des biologistes. La microscopie par rayons X dans la fenêtre de l'eau permet l'imagerie rapide de cellules dans leur milieu naturel, nécessite peu de préparation et offre des résolutions de quelques dizaines de nanomètres. De plus, il existe un bon contraste naturel entre les structures carbonées (protéines, lipides) et l'eau. Actuellement cette technique est limitée aux centres de rayonnement synchrotron, ce qui impose une planification et des déplacements incompatibles avec les besoins de la biologie. Un tel microscope fonctionnant avec uns source de laboratoire serait d'une grande utilité. Ce document présente un état de l'art de la microscopie par rayons X dans la fenêtre de l'eau. Un cahier des charges détaillé pour un appareil de laboratoire ayant les performances optiques requises par les biologistes est présenté et confronté aux microscopes X de laboratoire déjà existants. Des solutions concernant la source et les optiques sont également discutées.

  1. Islam et engagements au Sénégal : résultats d'un programme de recherche demandé par l'Ambassade du Royaume des Pay-Bas à Dakar

    NARCIS (Netherlands)

    Kaag, M.M.A.

    2011-01-01

    Ce volume collectif rassemble les résultats de travaux menés par des chercheurs sénégalais et néerlandais selon trois axes de recherche concernant le Sénégal: la relation entre islam et politique, la relation entre islam et économie, le rôle de l'islam dans le débat public sur la bonne gouvernance.

  2. Islam et engagements au Sénégal : résultats d'un programme de recherche demandé par l'Ambassade du Royaume des Pay-Bas à Dakar

    NARCIS (Netherlands)

    Kaag, M.M.A.

    2011-01-01

    Ce volume collectif rassemble les résultats de travaux menés par des chercheurs sénégalais et néerlandais selon trois axes de recherche concernant le Sénégal: la relation entre islam et politique, la relation entre islam et économie, le rôle de l'islam dans le débat public sur la bonne gouvernance.

  3. Optimization of a Brayton-Joule Engine Subject to Mass Transfer Limitations Due to Pressure Losses Optimisation d'un moteur Brayton-Joule soumis à des limitations de transfert de masse par suite de pertes de pression

    Directory of Open Access Journals (Sweden)

    Feidt M.

    2006-11-01

    Full Text Available In the paper proposed here we focus on a possible solar engine. We study the influence of mass transfer coupled to pressure losses on the maximum available power of the system. Dans la publication proposée ci-après, nous étudions un éventuel moteur solaire. L'influence du transfert de matière couplé aux pertes de pression sur le maximum de puissance pouvant être obtenu par un tel système est analysée.

  4. Quantification et caractérisation de la formation d'un biofilm sur du charbon actif dans des sédiments pollués par des PCB

    OpenAIRE

    Mercier, Anne; Wille, Guillaume; Michel, Caroline; Harris-Hellal, Jennifer; Amalric, Laurence; Morlay, Catherine; Battaglia-Brunet, Fabienne

    2012-01-01

    L'utilisation intensive des PCBs (polychlorinated biphenyls) dans l'industrie a eu pour conséquence la contamination de nombreux environnements aquatiques, conduisant ainsi à la bioaccumulation de ces molécules toxiques dans la chaine alimentaire. La bioremédiation des sédiments pollués par les techniques actuelles (dragage, ajout de sable in situ...) a généralement pour conséquences une re-suspension des PCBs dans la colonne d'eau et une destruction des écosystèmes. L'ajout in situ de charbo...

  5. Croissance epitaxiale de GaAs sur substrats de Ge par epitaxie par faisceaux chimiques

    Science.gov (United States)

    Belanger, Simon

    La situation energetique et les enjeux environnementaux auxquels la societe est confrontee entrainent un interet grandissant pour la production d'electricite a partir de l'energie solaire. Parmi les technologies actuellement disponibles, la filiere du photovoltaique a concentrateur solaire (CPV pour concentrator photovoltaics) possede un rendement superieur et mi potentiel interessant a condition que ses couts de production soient competitifs. La methode d'epitaxie par faisceaux chimiques (CBE pour chemical beam epitaxy) possede plusieurs caracteristiques qui la rendent interessante pour la production a grande echelle de cellules photovoltaiques a jonctions multiples a base de semi-conducteurs III-V. Ce type de cellule possede la meilleure efficacite atteinte a ce jour et est utilise sur les satellites et les systemes photovoltaiques a concentrateur solaire (CPV) les plus efficaces. Une des principales forces de la technique CBE se trouve dans son potentiel d'efficacite d'utilisation des materiaux source qui est superieur a celui de la technique d'epitaxie qui est couramment utilisee pour la production a grande echelle de ces cellules. Ce memoire de maitrise presente les travaux effectues dans le but d'evaluer le potentiel de la technique CBE pour realiser la croissance de couches de GaAs sur des substrats de Ge. Cette croissance constitue la premiere etape de fabrication de nombreux modeles de cellules solaires a haute performance decrites plus haut. La realisation de ce projet a necessite le developpement d'un procede de preparation de surface pour les substrats de germanium, la realisation de nombreuses sceances de croissance epitaxiale et la caracterisation des materiaux obtenus par microscopie optique, microscopie a force atomique (AFM), diffraction des rayons-X a haute resolution (HRXRD), microscopie electronique a transmission (TEM), photoluminescence a basse temperature (LTPL) et spectrometrie de masse des ions secondaires (SIMS). Les experiences ont permis

  6. Leçons d’analyse classique exposition d'un cours fait par Paul Koosis à l'Université McGill, Montréal

    CERN Document Server

    Poulin, Philippe

    2015-01-01

    Ce livre est basé sur un cours de deuxième cycle donné en 2005-2006 par M. Paul Koosis, professeur émérite à l'université McGill. Il traite de sujets soigneusement choisis par le professeur à l'intention de ceux qui, plutôt que de rechercher un catalogue exhaustif de résultats techniques et abstraits, veulent être initiés aux découvertes les plus essentielles et prolifiques de l'analyse classique du vingtième siècle. Analyse harmonique, quasi-analyticité, zéros des fonctions entières (dont une preuve inédite du théorème de Levinson-Cartwright), approximation pondérée, principe d'incertitude, mesures harmoniques…, les résultats saillants et géniaux de l'analyse classique sont présentés dans un style soigné, rigoureux et détaillé, préparant les étudiants à des études plus poussées ; et au service du lecteur qui, connaissant les bases de la théorie de la mesure et de l'analyse complexe, désire suivre le merveilleux développement de M. Koosis et accroître sa connaissance d...

  7. Conception d'un circuit d'etouffement pour photodiodes a avalanche en mode geiger pour integration heterogene 3d

    Science.gov (United States)

    Boisvert, Alexandre

    Le Groupe de Recherche en Appareillage Medical de Sherbrooke (GRAMS) travaille actuellement sur un programme de recherche portant sur des photodiodes a avalanche mono-photoniques (PAMP) operees en mode Geiger en vue d'une application a la tomographie d'emission par positrons (TEP). Pour operer dans ce mode; la PAMP, ou SPAD selon l'acronyme anglais (Single Photon Avalanche Diode), requiert un circuit d'etouffement (CE) pour, d'une part, arreter l'avalanche pouvant causer sa destruction et, d'autre part. la reinitialiser en mode d'attente d'un nouveau photon. Le role de ce CE comprend egalement une electronique de communication vers les etages de traitement avance de signaux. La performance temporelle optimale du CE est realisee lorsqu'il est juxtapose a la PAMP. Cependant, cela entraine une reduction de la surface photosensible ; un element crucial en imagerie. L'integration 3D, a base d'interconnexions verticales, offre une solution elegante et performante a cette problematique par l'empilement de circuits integres possedant differentes fonctions (PAMP, CE et traitement avance de signaux). Dans l'approche proposee, des circuits d'etouffement de 50 pm x 50 pm realises sur une technologie CMOS 130 mn 3D Tezzaron, contenant chacun 112 transistors, sont matrices afin de correspondre a une matrice de PAMP localisee sur une couche electronique superieure. Chaque circuit d'etouffement possede une gigue temporelle de 7,47 ps RMS selon des simulations faites avec le logiciel Cadence. Le CE a la flexibilite d'ajuster les temps d'etouffement et de recharge pour la PAMP tout en presentant une faible consommation de puissance (~ 0,33 mW a 33 Mcps). La conception du PAMP necessite de supporter des tensions superieures aux 3,3 V de la technologie. Pour repondre a ce probleme, des transistors a drain etendu (DEMOS) ont ete realises. En raison de retards de production par Ies fabricants, les circuits n'ont pu etre testes physiquement par des mesures. Les resultats de ce memoire

  8. The art of entrainment

    NARCIS (Netherlands)

    Roenneberg, T; Daan, S; Merrow, M

    The circadian system actively synchronizes the temporal sequence of biological functions with the environment. The oscillatory behavior of the system ensures that entrainment is not passive or driven and therefore allows for great plasticity and adaptive potential. With the tools at hand, we now can

  9. The art of entrainment

    NARCIS (Netherlands)

    Roenneberg, T; Daan, S; Merrow, M

    2003-01-01

    The circadian system actively synchronizes the temporal sequence of biological functions with the environment. The oscillatory behavior of the system ensures that entrainment is not passive or driven and therefore allows for great plasticity and adaptive potential. With the tools at hand, we now can

  10. Développement d'un système expert d'aide à la définition d'un programme de reconnaissance pour les tunnels

    OpenAIRE

    Laouini, H.; Deffayet, M.; Robert, A.; Gueniffey, Yves

    1992-01-01

    International audience; La definition d'un progranune de reconnaissance pour un projet de tunnel s'efforce de prendre en compte le plus completement possible le contexte particulier de chaque ouvrage, ainsi que l'ensemble des informations geologiques et geotechniques disponibles. La formalisation sous forme de regles de l'experience acquise dans ce domaine, et son traitement par Systeme expert permettent d'aider le specialiste dans son choix d'un Programme de reconnaissance adapte a la determ...

  11. Étude expérimentale de l'interaction laser-matière dans le cas du soudage d'un acier inoxydable austénitique par laser Nd:YAG continu de 2 kW

    Science.gov (United States)

    Dumord, E.; Jouvard, J. M.; Grevey, D.; Druetta, M.; Ottavi, P.

    1997-05-01

    The laser-matter interaction acting during cw 2 kW Nd:YAG laser welding of an austenitic stainless steel is studied and particulary the effects linked to the presence of a keyhole in the liquid bath. This is done in order to define parameters useful to the process modelling. The absorption factor of target has been measured in order to better understand the Nd:YAG laser/stainless steel 304 interaction. Then an experimental approach of the keyhole angle value determination is proposed. Values are presented showing the important keyhole angle at the bottom of the bead. Finally a study relative to the plume above the keyhole shows that it is responsible for the formation of the nail-head part, observed on the experimental melting zone, by laser beam scattering. L'interaction laser-matière se produisant lors du soudage par laser Nd:YAG continu de 2kW d'un acier inoxydable austénitique est étudiée, et notamment les effets liés à la présence du capillaire dans le bain liquide, de façon à définir les paramètres utiles à la modélisation du processus. Le facteur d'absorption des cibles utilisées a été mesuré afin de mieux appréhender l'interaction laser Nd:YAG/acier inoxydable austénitique 304. Puis une approche expérimentale de détermination de l'angle d'inclinaison du capillaire est proposée. Des valeurs sont présentées montrant la forte inclinaison du capillaire en fond de cordon. Finalement une étude relative au panache présent audessus du capillaire met en évidence qu'il est responsable de la formation de la partie en tête de clou observée sur les zones fondues expérimentales par diffusion du faisceau laser

  12. Water Entrainment in Concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    This report gives a survey of different techniques for incorporation of designed, water-filled cavities in concrete: Water entrainment. Also an estimate of the optimum size of the water inclusions is given. Water entrainment can be used to avoid self-desiccation and self-desiccation shrinkage...... during hydration [1,26]. What is needed is some sort of container which retains the shape of the water when mixed into the concrete. The container may function based on several different physical or chemical principles. Cells and gels are examples of containers found in nature. A cell membrane provides...... a boundary to water, whereas a polymer network incorporates water in its intersticious space with its affinity due to interaction energy and polymer entropy. Such containers allow water to be stored as an entity. In relation to concrete the water encapsulation may be accomplished either before or after start...

  13. Cfd Aided Development of a Si-Di Engine Aide au développement d'un moteur à injection directe d'essence par modélisation 3D

    Directory of Open Access Journals (Sweden)

    Henriot S.

    2006-12-01

    Full Text Available Gasoline Direct Injection (GDI appears to be the most relevant way to improve fuel efficiency of SI engines. But today, GDI is essentially regarded as a suitable technology for relatively high displacement engines, and the literature shows that the R&D effort on GDI engines is generally made for bores larger than 80 mm. For small bore engines (bore below 75 mm, locating an injector in already congested cylinder heads, with ultra lean stratified combustion capability while maintaining high engine specific power and proper cylinder head cooling is a real challenge. For such an engine, IFP is developing a 3-valve per cylinder engine (NSDI-3, based on a narrow spacingconcept, with a spark-plug-close-to-the-injector design and a suitable piston to confine the gasoline spray within the vicinity of the ignition location. This paper describes the contribution of 3D modeling to the development of this engine, from the initial work during the design of the prototype combustion chamber, to the development and tuning of the prototype engine on the test bench. Depuis quelques années, l'injection directe d'essence apparaÎt comme l'une des voies d'investigation les plus performantes pour améliorer le rendement des moteurs à allumage commandé. Cependant, cette technologie est, actuellement, plutôt réservée aux moteurs de cylindrée assez importante, et les travaux de R&D présentés dans la littérature font surtout état de développement pour des moteurs d'alésage supérieur à 80 mm. En ce qui concerne les petits moteurs (alésage inférieur à 75 mm, implanter un injecteur dans une culasse déjà largement encombrée, avec un fort potentiel de combustion en mélange très pauvre stratifié, tout en maintenant de bonnes performances moteur et un circuit de refroidissement bien dimensionné, constitue un véritable défi. Pour un tel moteur, l'Institut français du pétrole (IFP développe une solution à 3 soupapes par cylindre (NSDI-3, basée sur

  14. Permeability Damage Due to Asphaltene Deposition : Experimental and Modeling Aspects Endommagement d'un milieu poreux par dépôts d'asphaltènes : expériences et modélisation

    Directory of Open Access Journals (Sweden)

    Minssieux L.

    2006-12-01

    Full Text Available The flow properties of several asphaltenic crudes were studied at reservoir temperature in rocks of different morphology and mineralogy. The experiments performed showed a progressive reduction in permeability to oil during injection, varying in rate according to the system considered. The existence of organic deposits was verified by Rock-Evalpyrolysis measurements made on sections of samples taken at the end of flow at different distances from the entry face. This technique enables the profile of the deposits to be quantified. The interpretation of the permeability damage experiments and their simulation are treated by comparing the asphaltenes in oil to colloidal particles in suspension, capable of being deposited at the surface of the pores and thus reducing the permeability of the porous medium. The first simulations were carried out using the PARISIFP particle damage model, which has recently been extended to the case of multi-layer deposition. A satisfactory qualitative agreement is observed with the experimental results. Les propriétés d'écoulement de plusieurs bruts asphalténiques ont été étudiées à la température du réservoir d'origine dans des roches de morphologie et minéralogie différentes. Les expériences réalisées mettent en évidence une réduction progressive de la perméabilité à l'huile au cours de l'injection, plus ou moins rapide selon les cas. L'existence de dépôts organiques a été vérifiée par des mesures de pyrolyse Rock-Evaleffectuées sur des sections d'échantillons prélevées en fin d'écoulement à différentes distances de la face d'entrée. Cette technique permet de quantifier le profil des dépôts. L'interprétation des expériences de colmatage et leur simulation sont traitées en assimilant les asphaltènes dans l'huile à des particules colloïdales en suspension, susceptibles de se déposer à la surface des pores et ainsi de réduire la perméabilité du milieu poreux. Les premi

  15. Caractérisation de l'état chimique d'un élément par fluorescence X : l'aluminium dans les zéolithes Characterizing the Chemical State of an Element by X-Ray Fluorescence: Aluminium in Zeolites

    Directory of Open Access Journals (Sweden)

    Freund E.

    2006-11-01

    Full Text Available La fluorescence X est essentiellement connue dans le domaine de l'analyse quantitative, mais c'est aussi une méthode qui permet d'obtenir des informations détaillées sur la structure électronique des éléments. Dans cet article, nous montrons qu'il est possible de mettre au point une technique simple de caractérisation de l'état chimique d'un élément en utilisant de façon conjointe un spectromètre commercial et un programme adapté de traitement des données. Nous avons appliqué cette technique au cas de l'aluminium dans une zéolithe particulière : la mordénite dite à petits pores modifiée par différents traitements. Nous avons ainsi pu classer les solides suivant leur rapport (AI hexa-coordinné/AI tétracoordinné et montrer que le débouchage de la mordénite dite à petits pores est lié à l'extraction d'atomes d'aluminium de la charpente cristalline. X-ray fluorescence is mainly known in the field of qua-titative analysis, but it is also a useful method for obtaining detailed informations about the electronic structure of elements. This article shows that it is possible to develop a simple technique for characterizing the chemical state of an element by combining a commercial spectrometer with a program suited for data processing. This technique has been applied to the case of aluminum in a specific zeolite, ( small portmodernite, modified by various treatments. We were thus able to classify the solids according to the ratio of hexacoordinated AI/tetracoordinated AI and to show that the deblocking of the small portmordenite is linked to the extraction of aluminum atomrs from the crystalline structure.

  16. Macroscopic Equations Derived from Space Averaging for Immiscible Two-Phase Flow in Porous Media Équations macroscopiques d'un écoulement de deux phases immiscibles en milieu poreux déduites par prise de moyenne spatiale

    Directory of Open Access Journals (Sweden)

    Pavone D.

    2006-11-01

    courbures des fronts biphasiques. Avant d'entreprendre l'étude des écoulements instables en milieu poreux, il a semblé nécessaire de rechercher les équations des écoulements biphasiques non miscibles en milieu poreux qui soient les plus précises et les plus complètes possible. Partant des équations microscopiques exactes au niveau du pore, des variables macroscopiques et les équations qui les relient sont déduites à l'échelle macroscopique par prise de moyenne spatiale. La thermodynamique des processus irréversibles est ensuite utilisée pour fermer le système d'équations. On montre ainsi que la loi de Darcy généralisée à deux phases modélise les écoulements non miscibles, à condition toutefois de l'enrichir d'un terme de couplage visqueux. La loi de pression capillaire apparaît être la somme de deux termes statiques et un dynamique. Les termes statiques prennent en compte la quantité d'aire interfaciale (loi de Gibbs-Duhem ainsi que l'aire balayée par les lignes de contact triples (Loi de Laplace. Le terme dynamique prend en compte l'inertie des fluides. Cette décomposition de la pression capillaire en trois termes de sens physique évident est relativement originale. Ces travaux indiquent que la pression capillaire semble ne pas dépendre de la courbure macroscopique du front biphasique, même dans le cas d'instabilités visqueuses.

  17. Timescales of Massive Human Entrainment

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Perlman, Marcus; Mislove, Alan

    2014-01-01

    entrainment. We conducted a detailed investigation of the real time unfolding of human entrainment, as expressed by the content and patterns of hundreds of thousands of messages on Twitter, during the 2012 US presidential debates. By time locking these data sources, we quantify the real time impact...

  18. Circadian entrainment of Neurospora crassa

    NARCIS (Netherlands)

    Merrow, M.; Roenneberg, T.

    2007-01-01

    The circadian clock evolved under entraining conditions, yet most circadian experiments and much circadian theory are built around free-running rhythms. The interpretation of entrainment experiments is certainly more complex than that of free-running rhythms due to the relationship between exogenous

  19. Timescales of Massive Human Entrainment

    CERN Document Server

    Fusaroli, Riccardo; Mislove, Alan; Paxton, Alexandra; Matlock, Teenie; Dale, Rick

    2014-01-01

    The past two decades have seen an upsurge of interest in the collective behaviors of complex systems composed of many agents. In this paper, we extend concepts of entrainment to the dynamics of human collective attention. We demonstrate that large scale human entrainment may hold across a number of distinct scales, in an exquisitely time locked fashion. Using a large scale database of human communication data, we analyze and describe three different time scales of human entrainment in electronic media. We sought a distinct shared experience that provided a test bed for quantifying large scale human entrainment. We conducted a detailed investigation of the real time unfolding of human entrainment, as expressed by the content and patterns of hundreds of thousands of messages on Twitter, during the 2012 US presidential debates. By time locking these data sources, we quantify the real time impact of the debate on human attention. We show that social behavior covaries second by second to the interactional dynamics...

  20. Experimental Design: Application to the Development of a Treatment to Inhibit the Deposition of Barium Sulfate Liable to Be Formed in Enhanced Oil Recovery by Waterflooding Planification d'expériences : application à la mise au point d'un traitement inhibiteur du depôt de sulfate de baryum susceptible de se former en récupération assistée du pétrole par injection d'eau

    Directory of Open Access Journals (Sweden)

    Roque C.

    2006-11-01

    Full Text Available For technical and economic reasons, waterflooding is the most widely-used method in enhanced oil recovery [1]. In many situations, unfortunately, the formation water is incompatible with the injection water. The deposits and corrosion induced by the various reactions of this incompatibility cause irreversible damage, which is especially dangerous for the reservoir rock and the downhole and surface production facilities. This study is concerned exclusively with barium sulfate deposits liable to occur in surface production facilities by the mixing of injection water loaded with sulfate (1300 mg. 1 to the power of (-1 with a formation water with a high barium concentration (1200 mg. 1 to the power of (-1 [2]. Pour des raisons techniques et économiques, l'injection d'eau dans les réservoirs est la méthode la plus employée dans la récupération du pétrole. Malheureusement, dans bien des cas, l'eau en place dans le gisement est incompatible avec l'eau injectée. Les dépôts et les corrosions causés par les diverses réactions physico-chimiques de cette incompatibilité provoquent des dégradations irréversibles particulièrement dangereuses pour les installations de production de fond comme de surface et quelquefois pour la roche réservoir elle-même. Dans le cadre des travaux de recherche relatifs à l'inhibition des dépôts de sulfate sur le champ algérien de Tin Fouyé Tabankort, cette étude a eu pour objectif de sélectionner et d'adapter aux conditions spécifiques de la production un traitement de prévention des dépôts par injection d'un agent inhibiteur. Elle concerne exclusivement les dépôts de sulfate de baryum pouvant apparaître dans les installations de production par mélange d'eau d'injection très chargée en ion sulfate (1300 mg. 1 puissance(-1 avec une eau de gisement très concentrée en élément baryum (1200 mg. 1 puissance(-1. Une méthode expérimentale au laboratoire, faisant appel à des mesures de type

  1. Récuperation d'horloge d'un signal OTDM à 640 Gbit/s transmis sur 50 km par boucle à verrouillage de phase opto-électronique utilisant un dispositif en Niobate de Lithium à inversion de domaines

    DEFF Research Database (Denmark)

    Gomez, F.; Ware, Agis C.; Oxenløwe, Leif Katsuo;

    2008-01-01

    L'extraction d'horloge d'un signal OTDM à 640 Gbit/s, transmis sur 50 km, à partir d'une boucle à verrouillage de phase utilisant l'effet non-linéaire de mélange à trois ondes dans un composant de niobate de lithium à inversion de domaines a été mise en oeuvre....

  2. Entrained Flow Gasification of Biomass

    DEFF Research Database (Denmark)

    Qin, Ke

    of different fuels on syngas products was investigated at 1400 °C with steam addition. The yields of residual particulates (char and/or soot) decreased with increasing straw fraction during straw/wood co-gasification and with increasing biomass fraction (straw or wood) during biomass/coal co......, char-gas and soot-gas reactions, detailed gas-phase reactions, and mass and heat transfer. The model could reasonable predict the yields of syngas products obtained in the biomass gasification experiments. Moreover, the simulation results suggest that the soot can be completely converted and thereby......The present Ph. D. thesis describes experimental and modeling investigations on entrained flow gasification of biomass and an experimental investigation on entrained flow cogasification of biomass and coal. A review of the current knowledge of biomass entrained flow gasification is presented...

  3. Traitement des diagraphies acoustiques. Troisième partie : caractérisation d'un réservoir par diagraphies acoustiques obtenues avec un outil dipolaire Full-Waveform Acoustic Data Processing. Part Three: Reservoir Characterisation Using Acoustic Logs Obtained with the Dipole Sonic Imaging Tool

    Directory of Open Access Journals (Sweden)

    Wicquart E.

    2006-11-01

    Full Text Available En formation lente, l'utilisation d'un outil acoustique équipé d'émetteurs et de récepteurs dipolaires permet d'accéder à la lenteur S de la formation. Nous montrons comment un tel outil peut être utilisé pour caractériser un réservoir en formation lente. Le pointé des premières arrivées des différentes ondes composant un enregistrement acoustique en champ total permet d'accéder aux logs acoustiques classiques (lenteur, fréquence, atténuation ainsi qu'aux logs de dispersion de mesure qui leur sont associés. Ces logs conduisent à des logs de paramètres mécaniques notamment au coefficient de Poisson. Dans le cas du puits étudié traversant une formation argilo-gréseuse, le log du coefficient de Poisson et le log de fréquence des ondes de Stoneley sont utilisés comme indicateur lithologique d'argilosité et de présence d'hydrocarbures (gaz. Après correction d'argilosité, les logs de lenteur en onde compression et de cisaillement sont utilisés en combinaison avec un log densité de type Gardner pour estimer les paramètres pétrophysiques de la formation (indices de porosité et de saturation en gaz. Les résultats obtenus sont comparés à ceux fournis par l'analyse de logs classiques (neutron, densité. In slow formations, in which the velocity of the compression wave in mud is greater than the velocity of the shear wave in the formation, the slowness S of the formation can be determined only very indirectly (using Stoneley waves with a conventional monopole tool. For such formations, the use of a dipole tool makes it easier to gain access to this measurement and to obtain more complete information about the formation. This article shows how such a tool can be used for characterizing a slow-formation reservoir. The tool has a monopole transmitter capable of emitting low frequencies so as to favor interface modes and, at high frequencies, head waves (P refraction in the formation. The tool has two dipole transmitters

  4. Convertisseur de reequilibrage de la tension d'un reseau

    Science.gov (United States)

    Richardeau, Frédéric; Aouda, Noureddine; Meynard, Thierry

    1997-08-01

    This paper deals with the design, the control and the simulation of a voltage balancing static converter for a three phases utility distribution. Unbalancing sources and compensator structures are studied and compared. The balancing method consists in injecting the load currents negative and zero sequence in opposite phase by means of a PWM voltage source inverter. The identification of the load currents negative sequence is based on the fluctuating active and reactive power computing allowing a transient state compensation. A general formulation is proposed allowing to relate the unbalance parameters to the inverter design. The compensation currents and the DC voltage loops are studied and carried out. Presented simulation results allow to validate control loops and to refine the theoretical study on the basis of a specification. This study has been supported by a research contract between the LEEI and the CENTRALP Automatismes company. Cet article traite du dimensionnement, du pilotage et de la simulation d'un convertisseur statique de rééquilibrage dynamique de la tension d'un réseau de distribution. Les sources de déséquilibre sont identifiées et les structures statiques de rééquilibrage sont décrites. Le principe du rééquilibrage consiste en une compensation des systèmes inverse et homopolaire de courants au moyen d'un onduleur de tension en modulation de largeur d'impulsion. L'identification du système inverse de courants repose sur le calcul des puissances active et réactive fluctuantes mises en jeu par la charge déséquilibrée, permettant une compensatiori en régime transitoire. Une formulation générale du dimensionnement du compensateur est proposée permettant de lier les paramètres caractéristiques du déséquilibre à la valeur des éléments constitutifs. L'asservissement des courants et la régulation de la tension de l'onduleur sont analysés. Les résultats de simulation ont permis de valider et d'affiner l'étude théorique sur

  5. Une nouvelle technique de stabilisation en fréquence d'un laser sur une cavité de Fabry-Perot

    OpenAIRE

    1987-01-01

    Nous présentons une nouvelle méthode pour stabiliser la fréquence d'un laser sur le pic de transmission d'un résonateur de Fabry-Perot (F.P.). Au moyen d'un modulateur acousto-optique, on décale en fréquence une fraction du faisceau laser d'une quantité voisine de l'écart entre modes du F.P. Les faisceaux direct et décalé sont polarisés orthogonalement et appliqués à l'entrée du F.P. Les faisceaux transmis sont séparés par un prisme de Glan. En effectuant la différence entre ces deux pics de ...

  6. 48 CFR 204.7202-2 - DUNS numbers.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false DUNS numbers. 204.7202-2..., DEPARTMENT OF DEFENSE GENERAL ADMINISTRATIVE MATTERS Contractor Identification 204.7202-2 DUNS numbers. Requirements for use of DUNS numbers are in FAR 4.605(b) and 4.607(a)....

  7. Batch Extractive Distillation with Light Entrainer

    OpenAIRE

    Varga, Viktoria; Rev, Endre; Gerbaud, Vincent; Fonyo, Zsolt; Joulia, Xavier

    2006-01-01

    Use of a light entrainer in batch extractive distillation is justified when the mixture boils at a high temperature, or when an appropriate heavy or intermediate entrainer cannot be found. Feasibility of batch extractive distillation with light entrainer for separating minimum and maximum boiling azeotropes and close boiling mixtures is studied in this article. Our test mixtures are: ethanol/water (minimum boiling azeotrope) with methanol, water/ethylene diamine (maximum boiling azeotro...

  8. Batch extractive distillation with light entrainer

    OpenAIRE

    Varga, Viktoria; Rev, Endre; Gerbaud, Vincent; Lelkes, Zoltan; Fonyo, Zsolt; Joulia, Xavier

    2006-01-01

    Use of a light entrainer in batch extractive distillation is justified when the mixture boils at a high temperature, or when an appropriate heavy or intermediate entrainer cannot be found. Feasibility of batch extractive distillation with light entrainer for separating minimum and maximum boiling azeotropes and close boiling mixtures is studied in this article. Our test mixtures are: ethanol / water (minimum boiling azeotrope) with methanol, water / ethylene diamine (maximum boiling azeotrope...

  9. Diagnostic et analyse du fonctionnement d'un périmètre oasien. Cas de l'oasis de Fatnassa Nord, Kébili, sud tunisien

    OpenAIRE

    Ghazouani, W.; Marlet, Serge; Mekki, I.; Vidal, Alain

    2007-01-01

    International audience; Les performances de l'oasis de Fatnassa sont sous la dépendance d'un ensemble de contraintes physiques et de dysfonctionnements liés aux pratiques et comportements individuels face à la gestion collective de l'aménagement. Ces contraintes et dysfonctionnements ont été abordés sous l'angle de leur perception par les agriculteurs. Le fonctionnement du périmètre a ensuite été décrit sous la forme d'un arbre des problèmes permettant de synthétiser les principales causes et...

  10. IMPACT DU VIEILLISSEMENT THERMIQUE SUR L'EMISSION D'UN CONVERTISSEUR BUCK

    OpenAIRE

    Huang, He; Boyer, Alexandre; Ben Dhia, Sonia

    2014-01-01

    National audience; Cet article présente l'effet du vieillissement thermique d'un convertisseur de tension DC-DC sur son émission électromagnétique. Le rôle des différents composants actifs et passifs dans la variation de l'émission électromagnétique de l'ensemble est analysé. Le modèle équivalent du système proposé confirme l'augmentation du niveau d'émission induite par le stress à haute température.

  11. An entrainment model for fluid mud

    NARCIS (Netherlands)

    Kranenburg, C.

    1993-01-01

    An entrainment model for fluid mud is derived by integrating the equation for turbulent kinetic energy across the mixed layer and introducing some modelling assumptions. The resulting entrainment model is similar to models of mixed-layer deepening in lakes and reservoirs, but in addition accounts fo

  12. An entrainment model for fluid mud

    NARCIS (Netherlands)

    Kranenburg, C.

    1993-01-01

    An entrainment model for fluid mud is derived by integrating the equation for turbulent kinetic energy across the mixed layer and introducing some modelling assumptions. The resulting entrainment model is similar to models of mixed-layer deepening in lakes and reservoirs, but in addition accounts fo

  13. Using circadian entrainment to find cryptic clocks

    NARCIS (Netherlands)

    Eelderink-Chen, Zheng; Olmedo, Maria; Bosman, Jasper; Merrow, Martha

    2015-01-01

    Three properties are most often attributed to the circadian clock: a ca. 24-h free-running rhythm, temperature compensation of the circadian rhythm, and its entrainment to zeitgeber cycles. Relatively few experiments, however, are performed under entrainment conditions. Rather, most chronobiology pr

  14. Hématome spontané du méso de l'angle colique droit et du colon transverse compliquant un traitement par anti vitamine K: à propos d'un cas et revue de la littérature

    Science.gov (United States)

    Traoré, Ibrahim Alain; Zaré, Cyprien; Barro, Sié Drissa; Guibla, Ismaël

    2016-01-01

    L'hématome spontané du méso de l'angle colique droit et du transverse est une complication rare du traitement anticoagulant par antivitamine K. Nous rapportons un cas d'hématome spontané du méso de l'angle colique droit et du transverse associé à un hémopéritoine de grande abondance chez un patient traité par antivitamine K pour embolie pulmonaire consécutive à une fracture des plateaux tibiaux droits. Le diagnostic doit être fait en urgence. L’échographie abdominale et la tomodensitométrie confirment le diagnostic. Le traitement non opératoire est la règle. Le traitement chirurgical est indiqué en cas de complications telles que la rupture de l'hématome. PMID:27217878

  15. Entrained Flow Gasification of Biomass

    DEFF Research Database (Denmark)

    Qin, Ke

    concentration, larger feeder gas flow, and longer residence time. Wood, straw, and lignin had similar gasification behavior except with regard to soot formation. The soot yield was lowest during straw gasification possibly because of its high potassium content. The equilibrium product compositions under...... from straw gasification had quite low content of soot while high contents of volatilizable KCl and K2SO4, and thereby appeared as irregular crystals (> 100 nm). During lignin gasification, the filter sample mainly consisted of soot and nonvolatilizable inorganic matter. The parent wood particles...... the wood soot with respect to both oxidation and CO2 gasification. Besides, the wood soot produced at higher temperature was more reactive than the soot produced at lower temperature. Biomass and coal co-gasification experiments were performed in the same entrained flow reactor. The effect of mixing ratio...

  16. Disseny d'un amplificador classe D

    OpenAIRE

    Sangüesa Cremades, Kevin

    2010-01-01

    Diseny i muntatge en circuit imprés d'un amplificador commutat classe D. Disseny i testeig dels subsistemes i muntatge i verificació final. Permet treballar amb electrònica analògica i amb commutada, i amb dispositius de potencia mitjana. Potencia de sortida (aprox): 5 - 10 W.

  17. La simulation stochastique des fractures pour évaluer l'incertitude géotechnique dans le cas d'un tunnel en massif rocheux

    OpenAIRE

    2005-01-01

    Les massifs rocheux sont hétérogènes, discontinus et anisotropes. Le comportement mécanique d'un massif dépend fortement de la fracturation naturelle et de ses propriétés, qui doivent donc être prises en compte en particulier dans les travaux de creusement des ouvrages souterrains. On présente ici une application d'une méthodologie complète qui part de la géologie structurale d'un massif et arrive à la simulation géomécanique au voisinage d'un tunnel, en passant par l'analyse des données sur ...

  18. Calcul des paramètres électromagnétiques d'un moteur à réluctance à commutations par une méthode hybride: éléments finis. Equations intégrales de frontière

    Science.gov (United States)

    Omekanda, Avoki; Broche, Christian; Baland, René

    1992-11-01

    The switched reluctance motor (SRM) is a doubly salient electrical machine carrying simple windings in which flow unidirectional currents over appropriate rotor positions[1]. Because of its simplicity, robustness, and high efficiency[2, 3], SRM is evaluated for variable speed- and traction drives. In this paper, a quadratic two-dimensional technique founded upon Lagrange curvilinear elements and coupling finite element method (FEM)- and boundary integral equation method (BIEM) is used to calculate electromagnetic parameters in a SRM. The application of this method to two SRM prototypes provides an accurate analysis of the magnetostatic field and gives good values of the electromagnetic parameters of a SRM. Le moteur à réluctance à commutations est une machine électrique à structures saillantes au stator et au rotor et qui comporte des bobinages simples dans lesquels circulent des courants unidirectionnels pour des positions appropriées du rotor[1]. Grâce à sa simplicité, sa robustesse et son rendement élevé[2, 3], ce moteur à réluctance est apprécié dans les entraînements à vitesse variable et de traction. Dans cet article, nous présentons l'application d'une méthode quadratique bidimensionnelle qui couple des éléments finis (MEF) et la méthode des équations intégrales de frontière (MEIF) en vue du calcul des paramètres électromagnétiques d'un moteur à réluctance à commutations. L'application de cette méthode à deux prototypes fournit une analyse précise de la répartition du champ magnétique ainsi qu'une bonne prédiction des paramètres électromagnétiques de ces moteurs.

  19. Developpement D'un Modele Climatique Regional: Fizr Simulation des Conditions de Janvier de la Cote Ouest Nord Americaine

    Science.gov (United States)

    Goyette, Stephane

    1995-11-01

    Le sujet de cette these concerne la modelisation numerique du climat regional. L'objectif principal de l'exercice est de developper un modele climatique regional ayant les capacites de simuler des phenomenes de meso-echelle spatiale. Notre domaine d'etude se situe sur la Cote Ouest nord americaine. Ce dernier a retenu notre attention a cause de la complexite du relief et de son controle sur le climat. Les raisons qui motivent cette etude sont multiples: d'une part, nous ne pouvons pas augmenter, en pratique, la faible resolution spatiale des modeles de la circulation generale de l'atmosphere (MCG) sans augmenter a outrance les couts d'integration et, d'autre part, la gestion de l'environnement exige de plus en plus de donnees climatiques regionales determinees avec une meilleure resolution spatiale. Jusqu'alors, les MCG constituaient les modeles les plus estimes pour leurs aptitudes a simuler le climat ainsi que les changements climatiques mondiaux. Toutefois, les phenomenes climatiques de fine echelle echappent encore aux MCG a cause de leur faible resolution spatiale. De plus, les repercussions socio-economiques des modifications possibles des climats sont etroitement liees a des phenomenes imperceptibles par les MCG actuels. Afin de circonvenir certains problemes inherents a la resolution, une approche pratique vise a prendre un domaine spatial limite d'un MCG et a y imbriquer un autre modele numerique possedant, lui, un maillage de haute resolution spatiale. Ce processus d'imbrication implique alors une nouvelle simulation numerique. Cette "retro-simulation" est guidee dans le domaine restreint a partir de pieces d'informations fournies par le MCG et forcee par des mecanismes pris en charge uniquement par le modele imbrique. Ainsi, afin de raffiner la precision spatiale des previsions climatiques de grande echelle, nous developpons ici un modele numerique appele FIZR, permettant d'obtenir de l'information climatique regionale valide a la fine echelle spatiale

  20. étude du passage de l'état colloïdal à l'état ionique de solutions de silicates sodiques par spectrométries RMN 29Si et infrarouge

    Science.gov (United States)

    Couty, R.

    1998-02-01

    Silica sodic solutions with molar ratio Rms [ SiO2] /[ Na2O] of 4.56 to 1 were obtained by depolymerisation of amorphous silical gel in sodium hydroxide. Solutions have been characterized by Qn distribution and infrared spectra. The decrease in degree of polymerization of the silicate anions shifts the (1000 1100 cm-1) Si-O-Si frequencies to lower frequency. The solution colloid- ionic evolution occuring at Rms=2.27 is characterized by Q4 and 1075 cm-1 infrared band disappearance. Des solutions de silicate de sodium, dont les teneurs en silice étaient identiques mais dont les rapports (Rms) des concentrations molaires de SiO2 et de Na2O en solution étaient compris entre 4,56 et 1, ont été réalisées par dépolymérisation d'un gel de silice dans des solutions d'hydroxyde de sodium. Ces solutions ont été caractérisées par leurs distributions d'oligomères Qn et leurs spectres infrarouges. La dépolymérisation entraine une décroissance des fréquences de vibration des groupements (Si-O-Si) situées à (1000 1100 cm-1). Le passage de la solution de l'état colloïdal à l'état ionique, qui se fait pour un rapport Rms de 2,27 est caractérisé par la décroissance des Q3, la disparition des Q4 et de la composante infrarouge à 1075 cm-1.

  1. M(E)CANISMES MOL(E)CULAIRES IMPLIQU(E)S DANS L'ALT(E)RATION DU PH(E)NOTYPE DES CELLULES (E)PITHELIAL(E)S TUBULAIRES PAR LES CALPA(I)NES EXTRACELLULAIRES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-hui; Joelle Perez; Laurent Baud

    2008-01-01

    Objectif Rechercher les mécanismes moléculaires par lesquels des calpaines extracellulaires af-fectent l'adhérence et la mobilité des cellules épithéliales HK-2 dérivées du tubule proximal humain. Méthodes Western blot pour détecter le clivage des chaines α des intégrines; dosage radioimmunologique pour mesurer l' AMP cyclique intracellulaire; fluorescence-activated cell sorting (FACS) pour tester l' apoptose cellulaire. La morpholo-gie des cellules HK-2 a été observée et photographiée. Résultats (1) L ' exposition des cellules HK-2 à la calpaine μ n'a pas entrainé de clivage des chaines o3 et αV des intégrines; (2)l' exposition des cellules HK-2 à la calpaine μ entrainait une augmentation progressive de l' accumulation intracellulaire d' AMP cyclique (P<0.05) qui était associée une résistance cellulaire à l'apoptose(P <0. 05 ) ; (3)l'addition d'un inhibiteur pharmacologique de la protéine kinase A(PKA) prévenait totalement les modifications d'adhérence et de mobilité cellulaires induites par calpaine μ Conclusion Les calpaines externalisées peuvent modifier l' adherence et la mobilité cellulaires via un mécanisme qui implique l'accumulation d' AMP cyclique et l' activation de la PKA. Par ces mécanismes, les calpaines externalisées pourraient jouer un role dans l'induction de la réparation au cours de l'insuffucance rénale aiguё.

  2. Temperature compensation and entrainment in circadian rhythms

    Science.gov (United States)

    Bodenstein, C.; Heiland, I.; Schuster, S.

    2012-06-01

    To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24 h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles.

  3. Commande vectorielle d'un moteur asynchrone sans capteur

    Science.gov (United States)

    Ourth, T.

    1993-06-01

    A field-oriented control strategy for induction machines which does not use mechanical sensors is presented. The rotor flux is observed by a reduced-order Luenberger-type observer based on a model using a stator-fixed reference frame. An estimate of the rotation speed is derived from the flux vector, the measured stator currents and the field orientation angle. Simulations demonstrate that this control strategy performs well even in the presence of parameter variations up to ± 50% (resistances). Ce papier présente la commande par flux orienté d'une machine asynchrone sans capteur de vitesse ou de position. Le flux rotorique est évalué grâce à un observateur d'ordre réduit d'un type voisin de Luenberger travaillant dans un repère fixe statorique. L'estimation de la vitesse est obtenue à partir du module du flux rotorique, des courants statoriques mesurés et de l'angle d'orientation du flux rotorique. Cette étude basée sur des simulations démontre un comportement acceptable de la commande malgré la variation des paramètres comme les résistances de la machine.

  4. Entrainment Rate in Shallow Cumuli: Dependence on Entrained Dry Air Sources and Probability Density Functions

    Science.gov (United States)

    Lu, C.; Liu, Y.; Niu, S.; Vogelmann, A. M.

    2012-12-01

    In situ aircraft cumulus observations from the RACORO field campaign are used to estimate entrainment rate for individual clouds using a recently developed mixing fraction approach. The entrainment rate is computed based on the observed state of the cloud core and the state of the air that is laterally mixed into the cloud at its edge. The computed entrainment rate decreases when the air is entrained from increasing distance from the cloud core edge; this is because the air farther away from cloud edge is drier than the neighboring air that is within the humid shells around cumulus clouds. Probability density functions of entrainment rate are well fitted by lognormal distributions at different heights above cloud base for different dry air sources (i.e., different source distances from the cloud core edge). Such lognormal distribution functions are appropriate for inclusion into future entrainment rate parameterization in large scale models. To the authors' knowledge, this is the first time that probability density functions of entrainment rate have been obtained in shallow cumulus clouds based on in situ observations. The reason for the wide spread of entrainment rate is that the observed clouds are affected by entrainment mixing processes to different extents, which is verified by the relationships between the entrainment rate and cloud microphysics/dynamics. The entrainment rate is negatively correlated with liquid water content and cloud droplet number concentration due to the dilution and evaporation in entrainment mixing processes. The entrainment rate is positively correlated with relative dispersion (i.e., ratio of standard deviation to mean value) of liquid water content and droplet size distributions, consistent with the theoretical expectation that entrainment mixing processes are responsible for microphysics fluctuations and spectral broadening. The entrainment rate is negatively correlated with vertical velocity and dissipation rate because entrainment

  5. Influence d'un carbomère sur le comportement thixotrope de suspensions aqueuses de laponite

    OpenAIRE

    2006-01-01

    l'objet de cette étude porte sur l'influence de l'ajout d'un carbomère sur le comportement thixotrope de suspensions aqueuse de laponite. Les propriétés rhéologiques de dispersions de laponite et d'un système hybride composé de laponite et de carbomère sont étudiées. Les mesures rhéométriques sous contrainte imposée montrent bien l'existence d'une contrainte seuil qui est associée au caractère thixotrope et à la concentration du fluide étudié. L'influence du carbomère est mise en évidence par...

  6. Observations and modelling of snow avalanche entrainment

    Directory of Open Access Journals (Sweden)

    B. Sovilla

    2002-01-01

    Full Text Available In this paper full scale avalanche dynamics measurements from the Italian Pizzac and Swiss Vallée de la Sionne test sites are used to develop a snowcover entrainment model. A detailed analysis of three avalanche events shows that snowcover entrainment at the avalanche front appears to dominate over bed erosion at the basal sliding surface. Furthermore, the distribution of mass within the avalanche body is primarily a function of basal friction. We show that the mass distribution in the avalanche changes the flow dynamics significantly. Two different dynamical models, the Swiss Voellmy-fluid model and the Norwegian NIS model, are used to back calculate the events. Various entrainment methods are investigated and compared to measurements. We demon-strate that the Norwegian NIS model is clearly better able to simulate the events once snow entrainment has been included in the simulations.

  7. Cloud-Top Entrainment in Stratocumulus Clouds

    Science.gov (United States)

    Mellado, Juan Pedro

    2017-01-01

    Cloud entrainment, the mixing between cloudy and clear air at the boundary of clouds, constitutes one paradigm for the relevance of small scales in the Earth system: By regulating cloud lifetimes, meter- and submeter-scale processes at cloud boundaries can influence planetary-scale properties. Understanding cloud entrainment is difficult given the complexity and diversity of the associated phenomena, which include turbulence entrainment within a stratified medium, convective instabilities driven by radiative and evaporative cooling, shear instabilities, and cloud microphysics. Obtaining accurate data at the required small scales is also challenging, for both simulations and measurements. During the past few decades, however, high-resolution simulations and measurements have greatly advanced our understanding of the main mechanisms controlling cloud entrainment. This article reviews some of these advances, focusing on stratocumulus clouds, and indicates remaining challenges.

  8. Observations and modelling of snow avalanche entrainment

    OpenAIRE

    2002-01-01

    In this paper full scale avalanche dynamics measurements from the Italian Pizzac and Swiss Vallée de la Sionne test sites are used to develop a snowcover entrainment model. A detailed analysis of three avalanche events shows that snowcover entrainment at the avalanche front appears to dominate over bed erosion at the basal sliding surface. Furthermore, the distribution of mass within the avalanche body is primarily a function of basal fric...

  9. Washing of the AN-107 entrained solids

    Energy Technology Data Exchange (ETDEWEB)

    GJ Lumetta; FV Hoopes

    2000-03-31

    This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing on the composition of the entrained solids in the diluted AN-107 low-activity waste (LAW) sample. The objective of this work was to gather data on the solubility of the AN-107 entrained solids in 0.01 M NaOH, so that BNFL can evaluate whether these solids require caustic leaching.

  10. Faisabilité de localisation d'usagers de la route en détresse par la technique TDOA à l'aide d'un réseau de radiotéléphonie GSM. Rapport d'activités, décembre 2001 - décembre 2002

    OpenAIRE

    2002-01-01

    Contrat INRETS/Région Nord-Pas de Calais n°01-34-0092; Rapport de recherche; La précision de localisation recherchée au sein du réseau cellulaire dédié de deuxième et troisième génération est de l'ordre de grandeur de quelques mètres afin de pouvoir lever l'ambiguïté quant au sens de circulation emprunte par l'usager de la route. Ce paramètre est jugé majeur notamment sur autoroute. Dans la première partie du rapport, nous présentons les différentes étapes du processus de localisation des usa...

  11. PROCEDE DE GESTION DENERGIE DUN VEHICULE ELECTRIQUE

    OpenAIRE

    Granato, Giovanni; Zidani, Hasnaa

    2013-01-01

    L'invention se rapporte à un procédé de gestion d'énergie pour un véhicule électrique, comprenant un calculateur, un moteur électrique, une batterie électrique et un moteur thermique d'appoint utilisant un carburant et conçu pour aider la batterie à faire fonctionner ledit moteur électrique. La principale caractéristique d'un procédé selon l'invention est qu'il comprend les étapes suivantes : - une étape de sélection d'un trajet compris entre un point de départ et un point de destination, - u...

  12. Création d'un simulateur pour l'optimisation du trafic ferroviaire dans le cadre du projet VERONESE

    OpenAIRE

    2010-01-01

    Ce stage a fait l'objet d'un travail de neuf mois consacré à la création d'un simulateur de gestion du trafic ferroviaire intégrant un critère d'optimisation de l'énergie. Ce simulateur se base sur les travaux de J. Rodriguez dont le simulateur Alsitrag créé en 1994. Celui-ci est basé sur un algorithme de pilotage par la commande de jerk alors que le nouveau simulateur doit intégrer un algorithme de pilotage par commande de traction/freinage. Il se basera sur les sources d'Alsitrag avec une m...

  13. Restauration adaptative des contours par une approche inspiree de la prediction des performances

    Science.gov (United States)

    Rousseau, Kami

    En teledetection, les cartes de contours peuvent servir, entre autres choses, a la restitution geometrique, a la recherche d'elements lineaires, ainsi qu'a la segmentation. La creation de ces cartes est faite relativement tot dans la chaine de traitements d'une image. Pour assurer la qualite des operations subsequentes, il faut veiller a obtenir une carte de contours precise. Notre problematique est de savoir s'il est possible de diminuer la perte de temps liee au choix d'algorithme et de parametre en corrigeant automatiquement la carte de contours. Nous concentrerons donc nos efforts sur le developpement d'une methode de detection/restauration de contours adaptative. Notre methode s'inspire d'une technique de prediction des performances d'algorithmes de bas niveau. Elle consiste a integrer un traitement par reseau de neurones a une methode " classique " de detection de contours. Plus precisement, nous proposons de combiner la carte de performances avec la carte de gradient pour permettre des decisions plus exactes. La presente etude a permis de developper un logiciel comprenant un reseau de neurones entraine pour predire la presence de contours. Ce reseau de neurones permet d'ameliorer les decisions de detecteurs de contours, en reduisant le nombre de pixels de fausses alarmes et de contours manques. La premiere etape de ce travail consiste en une methode d'evaluation de performance pour les cartes de contours. Une fois ce choix effectue, il devient possible de comparer les cartes entre elles. Il est donc plus aise de determiner, pour chaque image, la meilleure detection de contours. La revue de la litterature realisee simultanement a permis de faire un choix d'un groupe d'indicateurs prometteurs pour la restauration de contours. Ces derniers ont servi a la calibration et a l'entrainement d'un reseau de neurones pour modeliser les contours. Par la suite, l'information fournie par ce reseau a ete combinee par multiplication arithmetique avec les cartes d

  14. Décontamination nucléaire par laser UV

    Science.gov (United States)

    Delaporte, Ph.; Gastaud, M.; Marine, W.; Sentis, M.; Uteza, O.; Thouvenot, P.; Alcaraz, J. L.; Le Samedy, J. M.; Blin, D.

    2003-06-01

    Le développement et l'utilisation de procédés propres pour le nettoyage ou la préparation de surfaces est l'une des priorités du milieu industriel. Cet intérêt est d'autant plus grand dans le domaine du nucléaire pour lequel la réduction des déchets est un axe de recherche important. Un dispositif de décontamination nucléaire par laser UV impulsionnel a été développé et testé. Il est composé. d'un laser à excimères de 1kW, d'un faisceau de fibres optiques et d'un dispositif de récupération des particules. Les essais réalisés en milieu actif ont démontré sa capacité à nettoyer des surfaces métalliques polluées par différents radioéléments avec des facteurs de décontamination généralement supérieurs à 10. Ce dispositif permet de décontaminer de grandes surfaces de géométrie simple en réduisant fortement la génération de déchets secondaires. Il est, à ce jour et dans ces conditions d'utilisations, le procédé de décontamination par voie sèche le plus efficace.

  15. Developpement d'un compresseur d'hydrogene base sur le cyclage thermique des hydrures metalliques

    Science.gov (United States)

    Laurencelle, Francois

    La compression de l'hydrogene est une etape incontournable de son utilisation dans l'industrie actuelle et dans les nouvelles applications energetiques de l'hydrogene (stockage stationnaire et transport). Les compresseurs mecaniques traditionnellement utilises posent plusieurs problemes d'ingenierie, de securite et de maintenance qui pourraient etre contournes en developpant de nouvelles technologies mieux adaptees a l'hydrogene. Dans cette these, notre objectif est de developper d'un compresseur d'hydrogene base sur les hydrures metalliques pouvant etre connecte a la sortie d'un electrolyseur fonctionnant a basse pression et d'ainsi repondre au besoin de productioncompression d'hydrogene decentralisee. La methodologie du projet comprend plusieurs etapes. Premierement, nous faisons la revue bibliographique des projets impliquant des compresseurs a hydrures metalliques. Deuxiemement, a travers des travaux experimentaux, nous recherchons des hydrures permettant une compression efficace entre 20 et 80°C. Les materiaux sont synthetises par fusion a arc electrique et caracterises sur bancs d'essais d'hydrogenation. La structure de certains materiaux est aussi investiguee par rayons X, methode de B.E.T. et microscopie electronique. Troisiemement, un reacteur d'hydrures est concu de maniere a promouvoir des echanges de chaleur rapides et efficaces. Quatriemement, le prototype et son interface de controle sont construits. Cinquiemement, le compresseur est caracterise pour en evaluer les performances en termes de debit et de capacite. Les resultats obtenus sont presentes dans trois articles publies et dans le chapitre 5 de cette these. Le compresseur (article I) est base sur trois hydrures (LaNi 4.8Sn0.2, LaNi5 et MMNi4.7Al0.3 ). Celui-ci permet d'atteindre un debit de compression de 10 a 20 L d'hydrogene par heure et son efficacite est, estimee a ˜5% par rapport a un compresseur adiabatique ideal. Il a ete demontre que l'efficacite pourrait etre augmentee en utilisant un

  16. De Par en Par (Wide Open), 1993.

    Science.gov (United States)

    De Par en Par, 1993

    1993-01-01

    This document consists of the four issues of the serial "De Par en Par" published during 1993. This serial provides lessons in Spanish for elementary school children. It is written by bilingual education teachers for use in the bilingual classroom. The magazine bases itself on the K-6 curriculum and offers a variety of activities for classroom…

  17. L'apprentissage des langues médiatisé par les technologies (ALMT – Étude d'un domaine de recherche émergent à travers les publications de la revue Alsic Technology-mediated language learning: an emergent research domain under study through the review of a French scientific journal's publications

    Directory of Open Access Journals (Sweden)

    Nicolas Guichon

    2012-11-01

    Full Text Available Dans cette étude, il est postulé que l'apprentissage des langues médiatisé par les technologies (ALMT est un domaine de recherche qui s'intéresse au développement et à l'intégration des technologies dans l'enseignement-apprentissage d'une langue. Ce domaine étant émergent, la présente recherche vise tout d'abord à comprendre comment s'est formée la communauté de chercheurs autour de cet objet. Puis, à travers l'analyse critique de 79 articles publiés dans la revue en ligne francophone Alsic entre 1998 et 2010, la présente contribution s'emploie à définir les contours épistémologiques de ce domaine en étudiant les moyens de production de connaissance.In this study, it is postulated that technology mediated language learning is a research domain that focuses on the design and integration of technologies for language learning and teaching. Because this domain is emergent, the present study first aims at understanding how a community of researchers has developed around this object. Then, thanks to the critical analysis of 79 articles published in Alsic, a French-speaking online journal, the present article endeavours to define the epistemological contours of this research domain by studying the means employed to produce knowledge.

  18. Exergy Analysis and Exergo-Economic Optimization of Industrial Processes Optimisation des procédés industriels par analyse exergétique et exergo-économique

    Directory of Open Access Journals (Sweden)

    Le Goff P.

    2006-11-01

    Full Text Available The overall evaluation of a process can be made by exergy accounting or by financial accounting. In all cases, a process can be optimized by determining the best compromise between the various input fluxes. L'évaluation globale d'un procédé peut être faite soit au moyen d'un bilan exergétique, soit par l'intermédiaire d'un bilan économique. Dans tous les cas, un procédé peut être optimisé en déterminant le meilleur compromis entre les différents flux mis en jeu.

  19. On dust entrainment in photoevaporative winds

    Science.gov (United States)

    Hutchison, Mark A.; Price, Daniel J.; Laibe, Guillaume; Maddison, Sarah T.

    2016-09-01

    We investigate dust entrainment by photoevaporative winds in protoplanetary discs using dusty smoothed particle hydrodynamics. We use unequal-mass particles to resolve more than five orders of magnitude in disc/outflow density and a one-fluid formulation to efficiently simulate an equivalent magnitude range in drag stopping time. We find that only micron-sized dust grains and smaller can be entrained in extreme-UV radiation-driven winds. The maximum grain size is set by dust settling in the disc rather than aerodynamic drag in the wind. More generally, there is a linear relationship between the base flow density and the maximum entrainable grain size in the wind. A pileup of micron-sized dust grains can occur in the upper atmosphere at critical radii in the disc as grains decouple from the low-density wind. Entrainment is a strong function of location in the disc, resulting in a size sorting of grains in the outflow - the largest grain being carried out between 10 and 20 au. The peak dust density for each grain size occurs at the inner edge of its own entrainment region.

  20. Entrainment and the cranial rhythmic impulse.

    Science.gov (United States)

    McPartland, J M; Mein, E A

    1997-01-01

    Entrainment is the integration or harmonization of oscillators. All organisms pulsate with myriad electrical and mechanical rhythms. Many of these rhythms emanate from synchronized pulsating cells (eg, pacemaker cells, cortical neurons). The cranial rhythmic impulse is an oscillation recognized by many bodywork practitioners, but the functional origin of this impulse remains uncertain. We propose that the cranial rhythmic impulse is the palpable perception of entrainment, a harmonic frequency that incorporates the rhythms of multiple biological oscillators. It is derived primarily from signals between the sympathetic and parasympathetic nervous systems. Entrainment also arises between organisms. The harmonizing of coupled oscillators into a single, dominant frequency is called frequency-selective entrainment. We propose that this phenomenon is the modus operandi of practitioners who use the cranial rhythmic impulse in craniosacral treatment. Dominant entrainment is enhanced by "centering," a technique practiced by many healers, for example, practitioners of Chinese, Tibetan, and Ayurvedic medicine. We explore the connections between centering, the cranial rhythmic impulse, and craniosacral treatment.

  1. Par-tjek Manualen

    DEFF Research Database (Denmark)

    Trillingsgaard, Tea; Due, Mattias Stølen; Nørr Fentz, Hanne;

    Par-tjek er et tilbud til par, der ønsker at styrke forholdet og forebygge vanskeligheder. Et Par-tjek består af et indledende online spørgeskema efterfulgt at to samtaler med en psykolog eller lignende vejleder. Ved den sidste samtale modtager parret en personlig feedback-rapport, som de kan...

  2. La création d'un service de documentation juridique : pour une utilisation raisonnée de la méthode systémique

    OpenAIRE

    Cottin, Stéphane

    1993-01-01

    Christiane Volant (dir.), Martine Prévot, Anny Maximin; La création d'un service de documentation est une opération complexe par essence. La méthode systémique y trouve un champ d'application particulièrement riche d'expériences et d'apprentissages. Le cas particulier de la création d'un service de documentation juridique pour le compte d'une institution publique (le Conseil constitutionnel) est ici développé.

  3. Food entrainment: major and recent findings.

    Science.gov (United States)

    Carneiro, Breno T S; Araujo, John F

    2012-01-01

    Mammals exhibit daily anticipatory activity to cycles of food availability. Studies on such food anticipatory activity (FAA) have been conducted mainly in nocturnal rodents. They have identified FAA as the behavioral output of a food entrained oscillator (FEO), separate of the known light entrained oscillator (LEO) located in the suprachiasmatic nucleus (SCN) of hypothalamus. Here we briefly review the main characteristics of FAA. Also, we present results on four topics of food anticipation: (1) possible input signals to FEO, (2) FEO substrate, (3) the importance of canonical clock genes for FAA, and (4) potential practical applications of scheduled feeding. This mini review is intended to introduce the subject of food entrainment to those unfamiliar with it but also present them with relevant new findings on the issue.

  4. Food entrainment: major and recent findings

    Directory of Open Access Journals (Sweden)

    Breno Tercio Santos Carneiro

    2012-11-01

    Full Text Available Mammals exhibit daily anticipatory activity to cycles of food availability. Studies on such food anticipatory activity (FAA have been conducted mainly in nocturnal rodents. They have identified FAA as the behavioral output of a food entrained oscillator (FEO, separate of the known light entrained oscillator (LEO located in the suprachiasmatic nucleus of hypothalamus (SCN. Here we briefly review the main characteristics of FAA. Also, we present results on four topics of food anticipation: (1 possible input signals to FEO, (2 FEO substrate, (3 the importance of canonical clock genes for FAA and (4 potential practical applications of scheduled feeding. This mini review is intended to introduce the subject of food entrainment to those unfamiliar with it but also present them with relevant new findings on the issue.

  5. Syndrome de Lynch: à propos d'un cas et revue de la litterature

    Science.gov (United States)

    Bouguenouch, Laila; Samri, Imane; Belhassan, Khadija; Sayel, Hanane; Abbassi, Meriame; Bennis, Sanae; Benajah, Dafr Allah; Ibrahimi, Adil; Amarti, Afaf; Ouldim, Karim

    2016-01-01

    Le syndrome de Lynch, ou cancer colorectal héréditaire sans polypose ou HNPCC (hereditary non-polyposis colorectal cancer), est la forme la plus fréquente de cancer colorectal héréditaire. Il conduit à une augmentation de la susceptibilité à développer des cancers, au premier rang le cancer colorectal, le cancer de l'endomètre chez les femmes, et dans une moindre mesure, d'autres cancers (ovaire, intestin grêle, estomac, voies excrétrices urinaires et hépatobiliaires). Ainsi, le risque cumulé de développer un cancer colorectal ou de l'endomètre à l’âge de 80 ans s’élève respectivement à 20 et 40%. Ces cancers sont caractérisés par leur contexte d'atteinte familiale, leur survenue à un âge précoce, ainsi que par le développement de cancers métachrones chez un même individu. Ce syndrome se transmet de manière autosomique dominante. Les gènes dont l'altération est associée à l'existence d'un syndrome HNPCC appartiennent à la famille des gènes de réparation des mésappariements de l'ADN (DNA mismatch repair ou MMR): MSH2, MLH1 et MSH6 sont impliqués, par ordre décroissant de fréquence, dans respectivement 35%, 25% et 2% des cas. Une surveillance coloscopique et gynécologique est proposée aux personnes porteuses d'une mutation constitutionnelle du gène MSH2, MLH1 ou MSH6. Nous rapportons une des premières observations marocaines d'un syndrome de Lynch dont la mutation constitutionnelle du gène MLH1 a été identifiée chez un des membres de la famille atteint d'un cancer du côlon. Suite à la demande d'autres sujets sains de la même famille, un diagnostic presymptomatique a été effectué conduisant à une stratégie de surveillance adaptée. A travers notre observation nous illustrons le rôle de l'oncogénétique dans la prise en charge des patients cancéreux et de leurs familles. PMID:27642480

  6. Mise au point d'un reacteur epitaxial CBE

    Science.gov (United States)

    Pelletier, Hubert

    Ce projet de maîtrise consiste à l'asservissement et la mise en marche d'un réacteur d'épi-taxie par jets chimiques au Laboratoire d'Épitaxie Avancée de l'Université de Sherbrooke. Le réacteur sert à la croissance dans l'ultravide de matériaux semi-conducteurs tels que l'arséniure de gallium (GaAs) et le phosphure d'indium-gallium (GaInP). La programmation LabVIEW™ et du matériel informatique de National Instruments sont utilisés pour asservir le réacteur. Le contrôle de la température de l'échantillon et de la pression de contrôle des réactifs de croissance dans le réacteur est assuré par des boucles de rétroaction. Ainsi, la température de l'échantillon est stabilisée à ±0, 4 °C, alors que les pressions de contrôle de gaz peuvent être modulées sur un ordre de grandeur en 2 à 4 secondes, et stabilisées à ±0, 002 Torr. Le système de pompage du réacteur a été amélioré suite à des mesures de vitesse de pompage d'une pompe cryogénique. Ces mesures révèlent une dégradation sur plus d'un ordre de grandeur de son pompage d'hydrogène avec l'opération à long terme. Le remplacement de la pompe cryogénique par une pompe turbo-moléculaire comme pompe principale a permis d'améliorer la fiabilité du système de pompage du système sous vide. D'autre part, la conductance du système d'acheminement de gaz et d'injection a été augmentée afin de réduire un effet mémoire des sources le système et faciliter la croissance de matériaux ternaires. Ainsi, des croissances de GaAs (100) sur substrat de même nature ont été effectuées et ont révélé un matériau de bonne qualité. Sa rugosité moyenne de 0,17 nm, mesurée par microscopie à force atomique, est très faible selon la littérature. De plus, une mobilité élevée des porteurs est obtenue à fort dopage au silicium, au tellure et au carbone, notamment une mobilité de 42 ± 9 cm2V -1s-1 des porteurs majoritaires '(trous) lors du dopage au carbone à 1, 5 · 1019

  7. Giovanni Duns Scoto: una introduzione bibliografica

    Directory of Open Access Journals (Sweden)

    Todescan, Franco

    2005-01-01

    Full Text Available O presente texto oferece um panorama geral do pensamento ético e político de Duns Scotus. Temas jurídicos e econômicos recebem também consideração especial. A exposição desses domínios da filosofia de Scotus é precedida por apontamentos sobre o papel da vontade na fundamentação da ação moral e dos conceitos de indivíduo e pessoa

  8. La pratique de l’hypnose, de la visualisation ou de l’autohypnose par des personnes atteintes d'un cancer : une transformation de soi ? The Practice of the Hypnosis, the Visualization or the Autohypnosis by Persons Affected with Cancer: a Transformation of the Self?

    Directory of Open Access Journals (Sweden)

    Clémentine Raineau

    2011-05-01

    Full Text Available Les recours à certaines « médecines douces » comme l’hypnose et la relaxation permettent-ils une reconfiguration des soins du cancer dans les itinéraires thérapeutiques ? À partir d’un travail de terrain ethnographique réalisé en Auvergne avec des personnes atteintes par cette maladie et avec leurs thérapeutes, nous montrons que ces techniques de soins permettent aux patients d’acquérir des compétences pratiques (autohypnose, visualisation et relaxation pratiquées sans guide en solitaire et d’être actifs dans la prise en charge de leur cancer, afin de faire face à certains effets de la maladie et des traitements. L’acquisition de ces techniques d’autonomisation permet la reconfiguration de l’itinéraire thérapeutique du malade en regard du Plan Personnalisé de Soin (PPS qui lui est proposé dans une unité d’oncologie française.L’apprentissage de la visualisation, qui se réalise à travers la découverte lors des séances d’une “matrice de l’imagination” ancrée dans le corps et son exploration (à travers la génération et la manipulation d’images, œuvre de plus à un travail de métamorphose qui tend à transformer les modalités de l’“être-au-monde”.Do hypnosis and relaxation practices allow for a reconfiguration of cancer care within therapeutic itineraries? From our fieldwork in Auvergne (France with persons affected by this disease and with their therapists, we have shown that these care techniques allow the patients to acquire practical skills (autohypnosis, self-visualization and self-relaxation and to be active in the care of their cancer, to face certain side effects of the disease and the treatments. The acquisition of these techniques of empowerment allows for the reconfiguration of the patient’s care paths vis-à-vis the “Plan Personnalisé de Soins” (Personalized Care Program proposed by a French oncology unit. The visualization training, which comes to fruition

  9. Developpement d'un vibrateur acoustique pour precipiter les defauts latents de circuits electroniques

    Science.gov (United States)

    Lafleur, Francois

    2003-08-01

    Le procede de deverminage, ou Environmental Stress Screening (ESS), est employe principalement dans le domaine de l'electronique pour reduire les mortalites infantiles des produits avant leur livraison. Il utilise usuellement des stimulations environnementales telles que les vibrations ou la temperature produites a l'aide d'equipements conventionnels d'essais qui sont tres couteux et difficiles a implanter. Le but de cette recherche est le developpement d'une nouvelle methode d'excitation vibratoire des plaques de circuits electroniques a moindre cout par l'emploi de l'excitation acoustique. Le projet a mene au developpement d'un vibrateur acoustique pouvant etre utilise lors d'implantations du procede ESS en milieu industriel. L'utilisation de cette nouvelle technologie et des methodes novatrices de personnalisation des spectres ESS proposees dans cette these permettent la precipitation de defaillances latentes presentes dans les produits electroniques de facon efficace et securitaire et ce, a moindre cout par rapport aux technologies concurrentes. La methodologie des travaux presentes dans cette these inclus: (1) La generation acoustique des vibrations sur les circuits; (2) L'analyse modale acoustique des circuits par des methodes a reference unique et a references multiples; (3) La precipitation de defauts latents typiques des circuits electroniques; (4) Une methode d'individualisation des spectres vibratoires tenant compte des caracteristiques structurelles des circuits; (5) La presentation de la configuration de l'equipement acoustique et les resultats d'implantation du procede. Nonobstant la fabrication, l'installation et la mise en service d'un equipement en milieu industriel (depuis le mois de mai 2002), ces travaux ont permis l'obtention de trois familles de brevets et la publication de six articles de conference: trois portant sur l'analyse modale a reference unique, un portant sur l'analyse modale a references multiples, un autre portant sur la

  10. Le Sycoscan : un système d'inspection des conteneurs par balayage radioscopique

    CERN Document Server

    Krystal Production

    1997-01-01

    La société Europ Scan, le port autonome du Havre et les douanes françaises ont conçu un système de contrôle par rayons X qui permet d’étudier par radiographie le contenu d'un chargement. Les conteneurs sont ainsi vérifiés sans être déchargés ou ouverts. On utilise des faisceaux de rayons X de faible énergie couplés à des détecteurs ultrasensibles inspirés de la chambre à fils de Georges Charpak.

  11. Extraction du thorium par la résine XAD16 modifiée.

    OpenAIRE

    Miraoui, Abdelkader

    2015-01-01

    l’extraction liquide-solide de Th (IV) est faite par une résine kimberlite XAD16, modifiée par l’imprégnation d'un acide phospholipidique (pentakidodécaèdre-diphonique) et une faible quantité de TBP. Des paramètres sont étudiés tels que: le temps d'équilibre, effet de la concentration initial, effet de PH, effet de la force ionique, température...etc.

  12. Enhanced Oil Recovery by a Horizontal Well Located Inside a Polymer Flood Pilot Récupération assistée des hydrocarbures par forage horizontal à l'intérieur d'un pilote d'injection de polymère

    Directory of Open Access Journals (Sweden)

    Foxonet F.

    2006-11-01

    configuration à 7 points inversée comportait un injecteur central entouré de 6 puits producteurs situés à 400 m de distance. On a procédé à l'injection d'une solution de polymère (de 1977 à 1983, puis d'eau. La section horizontale du puits CR 163 H est située à l'extrémité nord du pilote, à 350 m de l'injecteur, et suit à peu près la courbe du banc prévu. Son indice de productivité atteint près de 7 fois la moyenne des puits verticaux voisins. La coupe aqueuse a brusquement diminué en mars 1988, jusqu'en octobre 1988, puis s'est établie au même niveau que dans les puits environnants. Ce fait est manifestement dû au banc d'hydrocarbures créé par l'injection de polymère, qui fait du puits CR 163 H un outil efficace pour ce que l'on pourrait appeler Récupération géométriquement assistée des hydrocarbures .

  13. Drugs of Abuse Can Entrain Circadian Rhythms

    Directory of Open Access Journals (Sweden)

    Ann E. K. Kosobud

    2007-01-01

    Full Text Available Circadian rhythms prepare organisms for predictable events during the Earth's 24-h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.

  14. Air entrainment by plunging water jets

    NARCIS (Netherlands)

    Van de Sande, E.

    1974-01-01

    Gas entrainment caused by the impact of liquid jets upon liquid pool surfaces is a subject which has received too little attention. This well-known phenomenon,which occurs In nature and in numerous industrial operations, has only recently received interest from scientific workers. The influence on p

  15. Drugs of abuse can entrain circadian rhythms.

    Science.gov (United States)

    Kosobud, Ann E K; Gillman, Andrea G; Leffel, Joseph K; Pecoraro, Norman C; Rebec, G V; Timberlake, William

    2007-11-02

    Circadian rhythms prepare organisms for predictable events in the 24 h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.

  16. Laminar Entrained Flow Reactor (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-02-01

    The Laminar Entrained Flow Reactor (LEFR) is a modular, lab scale, single-user reactor for the study of catalytic fast pyrolysis (CFP). This system can be employed to study a variety of reactor conditions for both in situ and ex situ CFP.

  17. Washing of the AW-101 entrained solids

    Energy Technology Data Exchange (ETDEWEB)

    GJ Lumetta

    2000-03-31

    BNFL Inc. (BNFL) is under contract with the US Department of Energy, River Protection Project (DOE-RPP) to design, construct, and operate facilities for treating wastes stored in the single-shell and double-shell tanks at the Hanford Site, Richland, Washington. The DOE-BNFL RPP contract identifies two feeds to the waste treatment plant: (1) primarily liquid low-activity waste (LAW) consisting of less than 2 wt% entrained solids and (2) high-level waste (HLW) consisting of 10 to 200 g/L solids slurry. This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing on the composition of the entrained solids in the diluted AW-101 low-activity waste (LAW) sample. The objective of this work was to gather data on the solubility of the AW-101 entrained solids in 0.01 M NaOH, so that BNFL can evaluate whether these solids require caustic leaching. The work was conducted according to test plan BNFL-TP-29953-9, Rev. 0, LAW Entrained Solids Water Wash and Caustic Leach Testing. The test went according to plan, with no deviations from the test plan. Based on the results of the 0.01 M NaOH washing, a decision was made by BNFL to not proceed with the caustic leaching test. The composition of the washed solids was such that caustic leaching would not result in significant reduction in the immobilized HLW volume.

  18. La néphrotoxicite secondaire à l'hyperbilribinemie: à propos d'un cas

    Science.gov (United States)

    Jomni, Med Taieb; Largueche, Mouna; Kaab, Badreddine Ben; Abdelaal, Imen; Bellakhal, Syrine; Douggui, Med Hédi

    2015-01-01

    L'hyperbilirubinémie à des taux élevés est nephrotoxique par divers mécanismes allant de la tubulopathie proximale aux dépôts massifs de bilirubine. Cette entité bien que décrite depuis le début du vingtième siècle est souvent méconnue dans la littérature moderne. Nous rapportons le cas d'un patient présentant une cirrhose probablement d'origine médicamenteuse (Amiodarone*), dont la fonction rénale s'est altérée parallèlement à la majoration de l'hyperbilirubinémie. Aucune autre cause de l'insuffisance rénale aigue n'a été retrouvée. PMID:26977222

  19. Influence des inclusions sur la rupture d'un acier faiblement allié

    Science.gov (United States)

    Hausild, P.; Berdin, C.; Bompard, P.; Prioul, C.

    2003-03-01

    L'étude de la rupture d'un acier faiblement allié dans le domaine de la transition ductile fragile a permis de mettre en évidence la présence croissante, avec la température de sollicitation, d'amas d'inclusions de seconde phase sur les surfaces de rupture. On montre, à l'aide de modélisations par éléments finis, que ces amas jouent néanmoins un rôle mineur dans le déclenchement du clivage. En revanche, leur influence sur la propagation de la rupture ductile est importante. On peut alors expliquer l'anisotropie de la résilience en prenant en compte la géométrie des inclusions et leur répartition spatiale.

  20. Mesure optimale de tilt et déplacement d'un faisceau gaussien

    Science.gov (United States)

    Delaubert, V.; Treps, N.; Fabre, C.; Harb, C.; Lam, P. K.; Bachor, H.

    2006-10-01

    Nous réalisons une expérience de mesure optimale de petits déplacements d'un faisceau gaussien TEM{00}, basée sur une détection homodyne employant un oscillateur local TEM{10}. Nous montrons une amélioration de 56% du signal détecté par rapport à une détection à deux zones. Ce nouveau dispositif permet également de mesurer de façon optimale de petites valeurs de tilt, la quantité conjuguée du déplacement. Enfin, nous montrons que la compression du mode TEM{10} du faisceau incident permet une mesure de déplacement au delà de la limite quantique standard.

  1. Evaluation mécanique d'une dalle précontrainte par mesure de la courbure

    OpenAIRE

    COLLIN, B; TONNOIR, B

    2001-01-01

    L'évaluation mécanique d'un ouvrage d'art a été réalisée en utilisant conjointement, et pour la première fois sur une dalle isostatique en béton précontraint, deux prototypes de courburemètre du réseau des LPC. Cette évaluation s'est appuyée sur des mesures, faites en plusieurs sections, des variations de courbure causées par la circulation sur l'ouvrage d'un convoi de caractéristiques connues. D'un point de vue pratique, la facilité d'utilisation des courburemètres, simplement posés sur la c...

  2. On the Parameterization of Convective Entrainment:Inherent Relationships among Entrainment Parameters in Bulk Models

    Institute of Scientific and Technical Information of China (English)

    SUN Jianning

    2009-01-01

    In this paper,the equilibrium entrainment into a shear-free,linearly stratified atmosphere is discussed under the framework of bulk models,namely,the zero-order jump model (ZOM) and the first-order jump model (FOM).The parameterizations for the dimensionless entrainment rate versus the convective Richardson number in the two models are compared.Based on the assumption that the parameterized entrainment rates in ZOM and FOM should be the same,the inherent relationships among the entrainment parameters in the bulk models are revealed.These relationships are supported by tank experiments and large-eddy simulations.The validity of these inherent relationships indicates that,for a convective boundary layer growing into a linearly stratified free atmosphere,the only dominant factors of the growth rate are the turbulent buoyancy in the mixed layer and the stratification in the free atmosphere.In the point of the similarity view,the former is characterized by turbulent temperature and mixing length scales (mixed layer depth),and the latter is characterized by the lapse rate of potential temperature in the free atmosphere.Thus,the commonly-used Richardson number scheme for the parameterization of the entrainment rate is just as an equivalent description.The variability of the total entrainment flux ratio in FOM,which is connected with the entrainment zone thickness,can implicitly describe the effect of the stratification in the free atmosphere,but the entrainment zone thickness is not an independent parameter.These results demonstrate the validity of the hypothesis that there exists a similarity limit in which the mixed layer depth is the only lengthscale.

  3. Observational constraints on entrainment and the entrainment interface layer in stratocumulus

    Directory of Open Access Journals (Sweden)

    J. K. Carman

    2012-01-01

    Full Text Available Aircraft sampling of the stratocumulus-topped boundary layer (STBL during the Physics of Stratocumulus Top (POST experiment was primarily achieved using sawtooth flight patterns, during which the atmospheric layer 100 m above and below cloud top was sampled at a frequency of once every 2 min. The large data set that resulted from each of the 16 flights document the complex structure and variability of this interfacial region in a variety of conditions. In this study, we first describe some properties of the entrainment interface layer (EIL, where strong gradients in turbulent kinetic energy (TKE, potential temperature and moisture can be found. We find that defining the EIL by the first two properties tend to yield similar results, but that moisture can be a misleading tracer of the EIL. These results are consistent with studies using large-eddy simulations. We next utilize the POST data to shed light on and constrain processes relevant to entrainment, a key process in the evolution of the STBL that to-date is not well-represented even by high resolution models. We define "entrainment efficiency" as the ratio of the TKE consumed by entrainment to that generated within the STBL (primarily by cloud-top cooling. We find values for the entrainment efficiency that vary by 1.5 orders of magnitude, which is even greater than the one order magnitude that previous modeling results have suggested. Our analysis also demonstrate that the entrainment efficiency depends on the strength of the stratification of the EIL, but not on the TKE in the cloud top region. The relationships between entrainment efficiency and other STBL parameters serve as novel observational contraints for simulations of entrainment in such systems.

  4. Observational constraints on entrainment and the entrainment interface layer in stratocumulus

    Directory of Open Access Journals (Sweden)

    J. K. Carman

    2012-11-01

    Full Text Available Aircraft sampling of the stratocumulus-topped boundary layer (STBL during the Physics of Stratocumulus Top (POST experiment was primarily achieved using sawtooth flight patterns, during which the atmospheric layer 100 m above and below cloud top was sampled at a frequency of once every 2 min. The large data set that resulted from each of the 16 flights document the complex structure and variability of this interfacial region in a variety of conditions. In this study, we first describe some properties of the entrainment interface layer (EIL, where strong gradients in turbulent kinetic energy (TKE, potential temperature and moisture can be found. We find that defining the EIL by the first two properties tends to yield similar results, but that moisture can be a misleading tracer of the EIL. These results are consistent with studies using large-eddy simulations. We next utilize the POST data to shed light on and constrain processes relevant to entrainment, a key process in the evolution of the STBL that to-date is not well-represented even by high resolution models. We define "entrainment efficiency" as the ratio of the TKE consumed by entrainment to that generated within the STBL (primarily by cloud-top cooling. We find values for the entrainment efficiency that vary by 1.5 orders of magnitude, which is even greater than the one order magnitude that previous modeling results have suggested. Our analysis also demonstrates that the entrainment efficiency depends on the strength of the stratification of the EIL, but not on the TKE in the cloud top region. The relationships between entrainment efficiency and other STBL parameters serve as novel observational contraints for simulations of entrainment in such systems.

  5. EFFECTS OF ENTRAINED AIR MANNER ON CAVITATION DAMAGE*

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LUO Chao

    2011-01-01

    Early in 1953 the experiments by Peterka proved that air entrainment has effects on decreasing cavitation damage. This technology has been widely used in the release works of high dams since the inception of air entrainment in the Grand Goulee Dam in 1960. Behavior, mechanism and application of air entrainment for cavitation damage control have been investigated for over half century. However, severe cavitation damage happened due to complex mechanism of air entrainment. The effects of air entrainment are related to many factors, including geometric parameters, hydraulic parameters and entrained air manners. In the present work an experimental set-up for air entrainment was specially designed, the behavior of reducing cavitation damage was experimentally investigated in the three aspects of entrained air pressure, air tube aera and air tube number. The results show that magnitude of reduction of cavitation damage is closely related to the entrained air tube number as well as entrained air pressure, air tube aera, and that the effect through three air tubes is larger than that through single air tube although the entrained air tubes have the same sum of tube aera, that is, 1 + 1 + 1 > 3. Therefore, it is important to design an effective manner of air entrainment.

  6. FooPar

    DEFF Research Database (Denmark)

    Hargreaves, F. P.; Merkle, D.

    2013-01-01

    We present FooPar, an extension for highly efficient Parallel Computing in the multi-paradigm programming language Scala. Scala offers concise and clean syntax and integrates functional programming features. Our framework FooPar combines these features with parallel computing techniques. Foo...

  7. AW-101 entrained solids - Solubility versus temperature

    Energy Technology Data Exchange (ETDEWEB)

    GJ Lumetta; RC Lettau; GF Piepel

    2000-03-31

    This report describes the results of a test conducted by Battelle to assess the solubility of the solids entrained in the diluted AW-101 low-activity waste (LAW) sample. BNFL requested Battelle to dilute the AW-1-1 sample using de-ionized water to mimic expected plant operating conditions. BNFL further requested Battelle to assess the solubility of the solids present in the diluted AW-101 sample versus temperature conditions of 30, 40, and 50 C. BNFL requested these tests to assess the composition of the LAW supernatant and solids versus expected plant-operating conditions. The work was conducted according to test plan BNFL-TP-29953-7, Rev. 0, Determination of the Solubility of LAW Entrained Solids. The test went according to plan, with no deviations from the test plan.

  8. Exploring Entrainment Patterns of Human Emotion in Social Media.

    Science.gov (United States)

    He, Saike; Zheng, Xiaolong; Zeng, Daniel; Luo, Chuan; Zhang, Zhu

    2016-01-01

    Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace.

  9. Exploring Entrainment Patterns of Human Emotion in Social Media.

    Directory of Open Access Journals (Sweden)

    Saike He

    Full Text Available Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace.

  10. Alignment strategies for the entrainment of music and movement rhythms.

    Science.gov (United States)

    Moens, Bart; Leman, Marc

    2015-03-01

    Theories of entrainment assume that spontaneous entrainment emerges from dynamic laws that operate via mediators on interactions, whereby entrainment is facilitated if certain conditions are fulfilled. In this study, we show that mediators can be built that affect the entrainment of human locomotion to music. More specifically, we built D-Jogger, a music player that functions as a mediator between music and locomotion rhythms. The D-Jogger makes it possible to manipulate the timing differences between salient moments of the rhythms (beats and footfalls) through the manipulation of the musical period and phase, which affect the condition in which entrainment functions. We conducted several experiments to explore different strategies for manipulating the entrainment of locomotion and music. The results of these experiments showed that spontaneous entrainment can be manipulated, thereby suggesting different strategies on how to embark. The findings furthermore suggest a distinction among different modalities of entrainment: finding the beat (the most difficult part of entrainment), keeping the beat (easier, as a temporal scheme has been established), and being in phase (no entrainment is needed because the music is always adapted to the human rhythm). This study points to a new avenue of research on entrainment and opens new perspectives for the neuroscience of music.

  11. Rod Driven Frequency Entrainment and Resonance Phenomena

    Directory of Open Access Journals (Sweden)

    Christina Salchow

    2016-08-01

    Full Text Available A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α of each volunteer in the range from 0.40–2.30*α. 306-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90–1.10*α and half of the alpha frequency (0.40–0.55*α. No signs of resonance and frequency entrainment phenomena were revealed around 2.00*α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30–2.30*α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex.

  12. Rod Driven Frequency Entrainment and Resonance Phenomena

    Science.gov (United States)

    Salchow, Christina; Strohmeier, Daniel; Klee, Sascha; Jannek, Dunja; Schiecke, Karin; Witte, Herbert; Nehorai, Arye; Haueisen, Jens

    2016-01-01

    A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α) of each volunteer in the range from 0.40 to 2.30∗α. Three hundred and six-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90–1.10∗α) and half of the alpha frequency (0.40–0.55∗α). No signs of resonance and frequency entrainment phenomena were revealed around 2.00∗α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30–2.30∗α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex. PMID:27588002

  13. Diurnally entrained anticipatory behavior in archaea.

    Directory of Open Access Journals (Sweden)

    Kenia Whitehead

    Full Text Available By sensing changes in one or few environmental factors biological systems can anticipate future changes in multiple factors over a wide range of time scales (daily to seasonal. This anticipatory behavior is important to the fitness of diverse species, and in context of the diurnal cycle it is overall typical of eukaryotes and some photoautotrophic bacteria but is yet to be observed in archaea. Here, we report the first observation of light-dark (LD-entrained diurnal oscillatory transcription in up to 12% of all genes of a halophilic archaeon Halobacterium salinarum NRC-1. Significantly, the diurnally entrained transcription was observed under constant darkness after removal of the LD stimulus (free-running rhythms. The memory of diurnal entrainment was also associated with the synchronization of oxic and anoxic physiologies to the LD cycle. Our results suggest that under nutrient limited conditions halophilic archaea take advantage of the causal influence of sunlight (via temperature on O(2 diffusivity in a closed hypersaline environment to streamline their physiology and operate oxically during nighttime and anoxically during daytime.

  14. Sediment particle entrainment in an obstructed annular

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Bruno Venturini; Siqueira, Renato do Nascimento [Faculdade do Centro Leste (UCL), Serra, ES (Brazil). Lab. de Fenomenos de Transporte], e-mail: brunovl@ucl.br, e-mail: renatons@ucl.br

    2006-07-01

    Flow in an annular region with internal cylinder rotation is a classic problem in fluid mechanics and has been widely studied. Besides its importance as a fundamental problem, flow in annular regions has several practical applications. This project was motivated by an application of this kind of flow to the drilling of oil and gas wells. In this work, an erosion apparatus was constructed in order to study the effect of the internal cylinder rotation on particle entrainment in an obstructed annular space and bed package as well. The study also analyzed the influence of height of the particles bed on the process performance. The experiment was designed so that the internal cylinder rotation could be measured by an encoder. The fluid temperature was measured by a thermocouple and the experiments were carried out at the temperature of 25 deg C. The study revealed that the particle entrainment for the height of the bed that is close to the center of the cylinders is negligible and the internal cylinder rotation provokes the movement and packing of the bed. For lower height of the bed, with same dimension of the annular gap, the particle entrainment process was satisfactory and the bed compaction was smaller than in the previous case, leading to a more efficient cleaning process in the annular space. (author)

  15. Analyse et modélisation du comportement d'un adhésif dans un assemblage soumis à sollicitations cycliques de cisaillement

    OpenAIRE

    Créac'Hcadec, Romain; Thevenet, David; Cognard, Jean-Yves

    2011-01-01

    International audience; Les analyses expérimentales et numériques du comportement mécanique d'un adhésif dans un assemblage sont rendues particulièrement difficiles en raison de l'influence des effets de bords. Ces concentrations de contraintes, présentes aux extrémités du joint de colle et près de l'interface, peuvent être à l'origine de l'amorçage de fissures qui peuvent par la suite se propager dans l'adhésif. L'analyse du comportement sur le long terme d'un adhésif est donc rendue assez d...

  16. Apport de la modélisation des acteurs dans le cas de la mise en place d'un entrepôt universitaire

    OpenAIRE

    2007-01-01

    Nous abordons une nouvelle gouvernance des universités en empruntant le processus d'intelligence économique pour faire évoluer un système d'information universitaire en un système d'information stratégique universitaire. Le transfert d'un système d'information en système d'information décisionnel repose sur les bases métiers orientées vers les acteurs de l'université par la prise en compte de la modélisation des utilisateurs. Le développement d'un système d'information global de l'université ...

  17. Planification de la maintenance d'un parc de turbines-alternateurs par programmation mathematique

    Science.gov (United States)

    Aoudjit, Hakim

    A growing number of Hydro-Quebec's hydro generators are at the end of their useful life and maintenance managers fear to face a number of overhauls exceeding what can be handled. Maintenance crews and budgets are limited and these withdrawals may take up to a full year and mobilize significant resources in addition to the loss of electricity production. In addition, increased export sales forecasts and severe production patterns are expected to speed up wear that can lead to halting many units at the same time. Currently, expert judgment is at the heart of withdrawals which rely primarily on periodic inspections and in-situ measurements and the results are sent to the maintenance planning team who coordinate all the withdrawals decisions. The degradations phenomena taking place is random in nature and the prediction capability of wear using only inspections is limited to short-term at best. A long term planning of major overhauls is sought by managers for the sake of justifying and rationalizing budgets and resources. The maintenance managers are able to provide a huge amount of data. Among them, is the hourly production of each unit for several years, the repairs history on each part of a unit as well as major withdrawals since the 1950's. In this research, we tackle the problem of long term maintenance planning for a fleet of 90 hydro generators at Hydro-Quebec over a 50 years planning horizon period. We lay a scientific and rational framework to support withdrawals decisions by using part of the available data and maintenance history while fulfilling a set of technical and economic constraints. We propose a planning approach based on a constrained optimization framework. We begin by decomposing and sorting hydro generator components to highlight the most influential parts. A failure rate model is developed to take into account the technical characteristics and unit utilization. Then, replacement and repair policies are evaluated for each of the components then strategies are derived for the whole unit. Traditional univariate policies such as the age replacement policy and the minimal repair policy are calculated. These policies are extended to build alternative bivariate maintenance policy as well as a repair strategy where the state of a component after a repair is rejuvenated by a constant coefficient. These templates form the basis for the calculation of objective function for the scheduling problem. On one hand, this issue is treated as a nonlinear problem where the objective is to minimize the average total maintenance cost per unit of time on an infinite horizon for the fleet with technical and economic constraints. A formulation is also proposed in the case of a finite time horizon. In the event of electricity production variation, and given that the usage profile is known, the influence of production scenarios is reflected on the unit's components through their failure rate. In this context, prognoses on possible resources problems are made by studying the characteristics of the generated plans. On the second hand, the withdrawals are now subjected to two decision criteria. In addition to minimizing the average total maintenance cost per unit of time on an infinite time horizon, the best achievable reliability of remaining turbo generators is sought. This problem is treated as a biobjective nonlinear optimization problem. Finally a series of problems describing multiple contexts are solved for planning renovations of 90 turbo generators units considering 3 major components in each unit and 2 types of maintenance policies for each component.

  18. Relaxation plastique d'un film mince par émission de dislocations filantes vis

    Science.gov (United States)

    Bonnet, Roland; Youssef, Sami; Neily, Salem; Gutakowskii, A. K.

    2008-03-01

    The system formed by a thin film coherent with a crystalline substrate can relax its internal energy by annealing. Threading dislocations emitted after ten minutes annealing at 350 °C of the Si 0.68Ge 0.32/Si(001) heterostructure are observed in transmission electron microscopy, and then identified by comparison to simulated images of angular dislocations placed in a semi infinite medium. They are of screw character, which explains the rapid coverage of the interface by 60° dislocations oriented . To cite this article: R. Bonnet et al., C. R. Physique 9 (2008).

  19. Calcul d'une valeur d'un facteur epsilon par une formule int\\'egrale

    CERN Document Server

    Waldspurger, Jean-Loup

    2009-01-01

    Let d and m be two natural numbers of distinct parities. Let $\\pi$ be an admissible irreducible tempered representation of GL(d,F), where F is a p-adic field. We assume that $\\pi$ is self-dual. Then we can extend $\\pi$ as a representation $\\tilde{\\pi}$ of a non-connected group $GL(d,F)\\rtimes \\{1,\\theta\\}$. Let $\\rho$ be a representation of GL(m,F). We assume that it has similar properties as $\\pi$. Jacquet, Piatetski-Shapiro and Shalika have defined the factor $\\epsilon(s,\\pi\\times\\rho,\\psi)$. We prove that we can compute $\\epsilon(1/2,\\pi\\times\\rho,\\psi)$ by an integral formula where occur the characters of $\\tilde{\\pi}$ and $\\tilde{\\rho}$. It's similar to the formula which, for special orthogonal groups, computes the multiplicities appearing in the local Gross-Prasad conjecture.

  20. Controle d'attitude d'un lanceur en phase atmospherique approche par applications gardiennes

    Science.gov (United States)

    Dubanchet, Vincent

    In a first phase, the modelling process underlines the presence of highly time varying parameters during the ascent, due to a fast mass variation along with propellant consumption. Linearizing the dynamical equations at six main flight instants yields linear time invariant models to be considered during control design. Each of them is to be stabilized by one control law, while respecting given specifications. The synthesis becomes even more complex when the bending modes are taken into account. Moreover, scheduling appears necessary to deal with the time variations. Indeed it is shown that no single gain setting is able to respect all the specifications along the trajectory. Furthermore, increasing complexity when modelling a whole launch vehicle pushes one to consider the model's errors and uncertainties. They represent a major issue in this study since it is asked to ensure the nominal performances in a robust fashion. Owing to their properties, guardian maps appear to be the most suitable tool to deal with such a problem of scheduling with robust performances. In light of this, the development of synthesis methods based on guardian maps is the main contribution of the project. It appears that actual state of the art in this field is focused on theoretical issues, whereas practical ones could be improved. Two approches are presented in the memoire. The first one is based on a graphical approach consisting in drawing the vanishing locus of guardian maps. A program using image analysis techniques is devised to check automatically which gain settings satisfy the constraints. The second one is based on an optimisation procedure involving guardian maps. Starting with the open loop system, the iterative process proposed ends up with a satisfactory gain setting for the closed-loop. These methods are tried and tested for the launch vehicle, with specifications from ASTRIUM-ST. Their practical application is motivated by the system complexity, the different kinds of constraints and the essential need for robustness. Many restrictions that finally bring about the interest and the efficiency of guardian maps for such a problem.

  1. suPAR

    DEFF Research Database (Denmark)

    Hodges, Gethin W; Bang, Casper N; Wachtell, Kristian;

    2015-01-01

    The fundamental role of inflammation in cardiovascular disease (CVD) has prompted interest in numerous biomarkers that detect subclinical levels of inflammation. Soluble urokinase plasminogen activator receptor (suPAR) is a novel biomarker that correlates significantly with cardiovascular events ...

  2. Calculs analytiques des signaux d'absorption laser obtenus sur une vapeur de métaux produite par un faisceau électronique. Application à la mesure de la vitesse des atomes

    OpenAIRE

    1996-01-01

    Nous calculons la forme analytique d'un signal d'absorption laser à partir de la distribution des vitesses des atomes d'un métal, distribution représentée par un gaussienne déplacée. Ces atomes neutres sont produits par l'évaporation intense d'une cible liquide métallique à l'aide d'un faisceau ponctuel d'électrons. Nous démontrons que le signal obtenu passe continûment d'une forme gausienne, pour une faible largeur d'absorption, à une courbe qui présente un plateau quand la largeur augmente....

  3. PEDAGOGIE PAR PROJET: UNE ÉTUDE DE CAS DANS L'ENSEIGNEMENT SUPERIEUR TECHNOLOGIQUE

    Directory of Open Access Journals (Sweden)

    Ngo van Thien

    Full Text Available Cet article rapporte les résultats d'un questionnaire proposé aux étudiants d'une formation d'enseignement supérieur technologique en génie électrique et informatique industrielle. L'objectif de ce questionnaire est d'évaluer le profit que les étudiants ont retiré d'un enseignement des techniques de gestion de projet, et l'utilisation qu'ils en ont fait, d'une part au cours d'une série de travaux pratiques utilisant la pédagogie par projet, d'autre part au cours de leur stage de fin d'études en entreprise.

  4. An Observational Study of Entrainment Rate in Deep Convection

    OpenAIRE

    Xiaohao Guo; Chunsong Lu; Tianliang Zhao; Guang J. Zhang; Yangang Liu

    2015-01-01

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects...

  5. Traitement superficiel d'acier par laser excimère

    Science.gov (United States)

    Pereira, A.; Cros, A.; Delaporte, Ph.; Marine, W.; Sentis, M.

    2003-06-01

    Motivée par des nécessités économiques et environnementales, l'industrie est amenée à développer de nouveaux procédés propres, notamment pour les applications concernant la préparation de surface (nettoyage, décapage...). Dans ce domaine, l'utilisation du laser excinière présente de nombreux avantages. En effet, en raison d'un temps d'interaction de courte durée (ns), suivi d'un échauffement et d'un refroidissement rapide de la zone irradiée sur une profondeur très fine (μm), il est possible de modifier localement les propriétés physico-chimiques d'une surface sans changer les propriétés intrinsèques du matériau. Le but de nos travaux a consisté en l'étude des effets d'un traitement par laser excimère (XeCI) sur les propriétés chimiques (XPS et AES), structurales (XRD et GIXRD) et morphologiques (MEB) de surface d'acier. Outre le nettoyage de la surface, les analyses chimiques réalisées sur de l'acier ont mis en évidence pour des densités d'énergie importantes la formation d'une couche de Fe2O3 au détriment de FeOOH. Les observations MEB ont révélé la création de structures sphériques nanométriques. Ce traitement permet notamment d'améliorer la tenue à la corrosion de la surface.

  6. An Observational Study of Entrainment Rate in Deep Convection

    Directory of Open Access Journals (Sweden)

    Xiaohao Guo

    2015-09-01

    Full Text Available This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal, gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. In addition, entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.

  7. Spontaneous motor entrainment to music in multiple vocal mimicking species.

    Science.gov (United States)

    Schachner, Adena; Brady, Timothy F; Pepperberg, Irene M; Hauser, Marc D

    2009-05-26

    The human capacity for music consists of certain core phenomena, including the tendency to entrain, or align movement, to an external auditory pulse [1-3]. This ability, fundamental both for music production and for coordinated dance, has been repeatedly highlighted as uniquely human [4-11]. However, it has recently been hypothesized that entrainment evolved as a by-product of vocal mimicry, generating the strong prediction that only vocal mimicking animals may be able to entrain [12, 13]. Here we provide comparative data demonstrating the existence of two proficient vocal mimicking nonhuman animals (parrots) that entrain to music, spontaneously producing synchronized movements resembling human dance. We also provide an extensive comparative data set from a global video database systematically analyzed for evidence of entrainment in hundreds of species both capable and incapable of vocal mimicry. Despite the higher representation of vocal nonmimics in the database and comparable exposure of mimics and nonmimics to humans and music, only vocal mimics showed evidence of entrainment. We conclude that entrainment is not unique to humans and that the distribution of entrainment across species supports the hypothesis that entrainment evolved as a by-product of selection for vocal mimicry.

  8. Hydrogéologie d'un bassin endoréique semi-aride : le bassin versant de la grande Sebkha d'Oran (Algérie)

    OpenAIRE

    Hassani, Moulay Idriss

    1987-01-01

    Le bassin versant de la Sebkha d'Oran , allongé du Nord-Est au Sud-Ouest ,forme un bassin sédimentaire sublittoral ; bordé au Nord par les massifs littoraux (Murdjadjo) et au Sud par les monts Tessalas. L'étude hydro climatologique confirme un climat de type seml aride. Les données de la pluviométrie, de l'évapotranspiration et du ruissellement, ont permis l'établissement d'un bilan hydrologique. La structure géologique détermine deux grands ensembles: - un substratum ante-synchro-nappe affle...

  9. TRANSFORMATION ISOTHERME D'UN ACIER A HAUTE RESISTANCE 40 CDV 13

    Directory of Open Access Journals (Sweden)

    A BOUTEFNOUCHET

    2001-06-01

    Full Text Available L'étude dilatométrique du comportement de l'austénite en condition isotherme d'un acier ternaire, à haute résistance mécanique de nuance 40 CDV 13, nous a permis de tracer son diagramme TTT. L'austénitisation a été réalisée pendant 10 minutes à  qg = 950°C (utilisée dans  l'industrie. Les températures de maintien sont comprises entre Ac1 = 810°C et Ms  = 310°C. Dans ce diagramme TTT, on distingue deux domaines de transformation isotherme de l'austénite. Le domaine I (625°C £  qiso < Ac1 = 810°C dans lequel l'austénite se transforme en ferrite et en perlite, et le domaine II (325°C  £  qiso £ 475°C où l'austénite se transforme en bainite ou en ferrite probainitique. Ces transformations sont précédées pour toutes les températures de maintien isotherme d'une précipitation de carbures. En outre, ces deux domaines de transformation de l'austénite sont séparés par une large zone de stabilité de l'austénite comprise entre 500°C et 600°C. L'analyse approfondie des courbes dilatométriques enregistrées durant le maintien isotherme et le refroidissement final jusqu'à l'ambiante, nous a permis de déterminer qualitativement et quantitativement les phase mises en jeu par ces transformations isothermes de l'austénite.

  10. La représentation de l'espace en Égypte ancienne: cartographie d'un itinéraire d'expédition

    Directory of Open Access Journals (Sweden)

    Michel BAUD

    1989-09-01

    Full Text Available L'unique carte topographique léguée par l'Égypte pharaonique, conservée sur un papyrus du XIIe siècle avant J.C., présente une partie du désert oriental égyptien. L'étude de sa structure montre qu'il s'agit plus d'un itinéraire que d'une carte, au sens actuel du terme.

  11. PROPOSITION D'UN MODELE DE L'EFFICACITE DU CO-COMMISSARIAT AUX COMPTES DANS LES SOCIETES ANONYMES COTEES FRANÇAISES

    OpenAIRE

    Bennecib, Jeannette

    2002-01-01

    International audience; Si le commissariat aux comptes est une institution reconnue par un large public, le co-commissariat aux comptes semble ignoré. Dans un contexte de remise en cause de la crédibilité des informations financières et de l'opinion de l'auditeur, nous nous interrogeons sur l'efficacité d'un double contrôle dans les SA cotées françaises. A partir du cadre conceptuel normatif de l'efficacité du cocommissariat aux comptes, nous proposons un modèle explicatif fondé sur le princi...

  12. Les transformations d'un mythe d'origine L'exemple de Gengis Khan et de Tamerlan

    Directory of Open Access Journals (Sweden)

    Denise Aigle

    2009-05-01

    Full Text Available La figure de Gengis Khan, grand conquérant et fondateur de dynastie, correspond étroitement à la figure du héros. Sa vie est jalonnée des signes d'un destin extraordinaire, en particulier sa naissance présentée comme miraculeuse, dont le récit a été transformé à mesure que ses descendants puis ses épigones s'éloignaient des origines mongoles chamaniques du grand ancêtre. Le récit de la naissance de Gengis Khan se rattache d'abord au mythe d'origine des Mongols qui descendraient de « Loup-bleu » et de « Biche-Fauve », récit lui-même visiblement inspiré du mythe des Turcs. Selon {'Histoire secrète des Mongols, de peu postérieure à la mort de Gengis Khan, l'ancêtre de celui-ci, Alan-Qo'a, veuve, aurait été fécondée par un être « qui sortait en rampant tel un chien jaune ». Ce rôle joué par un animal est conforme au chamanisme, qui repose sur un système d'échange entre le monde animal et celui des humains. Quelques décennies plus tard, le Jàmi' al-tawârikh de Rashïd al-dïn reprend la même légende, mais ne parle que d'un « être de couleur fauve ». Par la suite, les références animales disparaissent totalement dans un contexte musulman complètement détaché des repères chamaniques. Dans la première moitié du XVe siècle, les inscriptions relevées dans le mausolée de Tamerlan, mentionnent un rayon lumineux qui se manifeste sous la forme d'un « mortel accompli " descendant de 'Ali. Dans l'Inde moghole, enfin, Gengis Khan se trouve rapproché de Jésus puisque l'auteur de l'Akbar-nâma écrit que son ancêtre est devenue enceinte de la même manière que Maryam.

  13. Textilome abdominal, à propos d'un cas

    OpenAIRE

    Erguibi, Driss; Hassan, Robleh; Ajbal, Mohamed; Kadiri, Bouchaib

    2015-01-01

    Le textilome, également appelé gossybipomas, est une complication postopératoire très rare. Il peut s'agir d'un corps étranger composé de compresse(s) ou champ(s) chirurgicaux oubliés au niveau d'un foyer opératoire. Ils sont plus souvent asymptomatiques, et difficile à diagnostiquer. En particulier, les cas chroniques ne présentent pas de signes cliniques et radiologiques spécifiques pour le diagnostic différentiel. L'anamnèse est donc indispensable pour le diagnostic vu que les signes clini...

  14. METAFÍSICA Y ESPIRITUALIDAD DEL AMOR EN DUNS ESCOTO

    OpenAIRE

    Gloria Silvana Elías

    2013-01-01

    Este escrito se inscribe dentro de la teoría extática del amor según Duns Escoto, la que está influenciada por la doctrina de San Anselmo respecto de las dos inclinaciones o afectos de la voluntad: la affectio commodi y la affectio iustitiae. El objetivo del mismo es mostrar cómo Juan Duns Escoto logra superar la aparente contradicción que cabe entre tender por naturaleza a Dios y elegir a Dios a partir de la reflexión sobre los dos afectos que conforman la voluntad humana.

  15. METAFÍSICA Y ESPIRITUALIDAD DEL AMOR EN DUNS ESCOTO

    Directory of Open Access Journals (Sweden)

    Gloria Silvana Elías

    2013-06-01

    Full Text Available Este escrito se inscribe dentro de la teoría extática del amor según Duns Escoto, la que está influenciada por la doctrina de San Anselmo respecto de las dos inclinaciones o afectos de la voluntad: la affectio commodi y la affectio iustitiae. El objetivo del mismo es mostrar cómo Juan Duns Escoto logra superar la aparente contradicción que cabe entre tender por naturaleza a Dios y elegir a Dios a partir de la reflexión sobre los dos afectos que conforman la voluntad humana.

  16. It's quicker "Par Avignon"!

    CERN Multimedia

    2005-01-01

    For a few years, the CERN Library has been receiving books from the University of Hanover sent via Avignon, at least that's what it says on the envelope. Such a detour would mean that parcels were travelling 720 km more than the distance separating Geneva and Hanover, which would be a very strange state of affairs. The explanation lies in a spelling mistake. The sender has been stamping parcels with a stamp that says "Par Avignon prioritaire" (first-class via Avignon) instead of "Par Avion prioritaire" (First Class Air Mail), a source of much amusement to the librarians!

  17. Maximal air bubble entrainment at liquid-drop impact

    NARCIS (Netherlands)

    Bouwhuis, W.; van der Veen, Roeland; Tran, Tuan; Keij, D.L.; Winkels, K.G.; Peters, I.R.; van der Meer, Roger M.; Sun, Chao; Snoeijer, Jacobus Hendrikus; Lohse, Detlef

    2012-01-01

    At impact of a liquid drop on a solid surface, an air bubble can be entrapped. Here, we show that two competing effects minimize the (relative) size of this entrained air bubble: for large drop impact velocity and large droplets, the inertia of the liquid flattens the entrained bubble, whereas for

  18. Entrainment of circadian rhythm by ambient temperature cycles in mice.

    Science.gov (United States)

    Refinetti, Roberto

    2010-08-01

    Much is known about how environmental light-dark cycles synchronize circadian rhythms in animals. The ability of environmental cycles of ambient temperature to synchronize circadian rhythms has also been investigated extensively but mostly in ectotherms. In the present study, the synchronization of the circadian rhythm of running-wheel activity by environmental cycles of ambient temperature was studied in laboratory mice. Although all mice were successfully entrained by a light-dark cycle, only 60% to 80% of the mice were entrained by temperature cycles (24-32 degrees C or 24-12 degrees C), and attainment of stable entrainment seemed to take longer under temperature cycles than under a light-dark cycle. This suggests that ambient temperature cycles are weaker zeitgebers than light-dark cycles, which is consistent with the results of the few previous studies using mammalian species. Whereas 80% of the mice were entrained by 24-h temperature cycles, only 60% were entrained by 23-h cycles, and none was entrained by 25-h cycles. The results did not clarify whether entrainment by temperature cycles is caused directly by temperature or indirectly through a temperature effect on locomotor activity, but it is clear that the rhythm of running-wheel activity in mice can be entrained by ambient temperature cycles in the nonnoxious range.

  19. Macroscopic entrainment of periodically forced oscillatory ensembles.

    Science.gov (United States)

    Popovych, Oleksandr V; Tass, Peter A

    2011-03-01

    Large-amplitude oscillations of macroscopic neuronal signals, such as local field potentials and electroencephalography or magnetoencephalography signals, are commonly considered as being generated by a population of mutually synchronized neurons. In a computational study in generic networks of phase oscillators and bursting neurons, however, we show that this common belief may be wrong if the neuronal population receives an external rhythmic input. The latter may stem from another neuronal population or an external, e.g., sensory or electrical, source. In that case the population field potential may be entrained by the rhythmic input, whereas the individual neurons are phase desynchronized both mutually and with their field potential. Intriguingly, the corresponding large-amplitude oscillations of the population mean field are generated by pairwise desynchronized neurons oscillating at frequencies shifted far away from the frequency of the macroscopic field potential.

  20. Synchronization and entrainment of coupled circadian oscillators

    CERN Document Server

    Komin, Niko; Hernandez-Garcia, Emilio; Toral, Raul

    2010-01-01

    Circadian rhythms in mammals are controlled by the neurons located in the suprachiasmatic nucleus of the hypothalamus. In physiological conditions, the system of neurons is very efficiently entrained by the 24-hour light-dark cycle. Most of the studies carried out so far emphasize the crucial role of the periodicity imposed by the light dark cycle in neuronal synchronization. Nevertheless, heterogeneity as a natural and permanent ingredient of these cellular interactions is seemingly to play a major role in these biochemical processes. In this paper we use a model that considers the neurons of the suprachiasmatic nucleus as chemically-coupled modified Goodwin oscillators, and introduce non-negligible heterogeneity in the periods of all neurons in the form of quenched noise. The system response to the light-dark cycle periodicity is studied as a function of the interneuronal coupling strength, external forcing amplitude and neuronal heterogeneity. Our results indicate that the right amount of heterogeneity hel...

  1. Entrainment of neural oscillations as a modifiable substrate of attention.

    Science.gov (United States)

    Calderone, Daniel J; Lakatos, Peter; Butler, Pamela D; Castellanos, F Xavier

    2014-06-01

    Brain operation is profoundly rhythmic. Oscillations of neural excitability shape sensory, motor, and cognitive processes. Intrinsic oscillations also entrain to external rhythms, allowing the brain to optimize the processing of predictable events such as speech. Moreover, selective attention to a particular rhythm in a complex environment entails entrainment of neural oscillations to its temporal structure. Entrainment appears to form one of the core mechanisms of selective attention, which is likely to be relevant to certain psychiatric disorders. Deficient entrainment has been found in schizophrenia and dyslexia and mounting evidence also suggests that it may be abnormal in attention-deficit/hyperactivity disorder (ADHD). Accordingly, we suggest that studying entrainment in selective-attention paradigms is likely to reveal mechanisms underlying deficits across multiple disorders.

  2. Extraordinary behavioral entrainment following circadian rhythm bifurcation in mice.

    Science.gov (United States)

    Harrison, Elizabeth M; Walbeek, Thijs J; Sun, Jonathan; Johnson, Jeremy; Poonawala, Qays; Gorman, Michael R

    2016-12-08

    The mammalian circadian timing system uses light to synchronize endogenously generated rhythms with the environmental day. Entrainment to schedules that deviate significantly from 24 h (T24) has been viewed as unlikely because the circadian pacemaker appears capable only of small, incremental responses to brief light exposures. Challenging this view, we demonstrate that simple manipulations of light alone induce extreme plasticity in the circadian system of mice. Firstly, exposure to dim nocturnal illumination (entrainment. Continuation of dim light is unnecessary for T15/30 behavioral entrainment following bifurcation. Finally, neither dim light alone nor a shortened night is sufficient for the extraordinary entrainment observed under bifurcation. Thus, we demonstrate in a non-pharmacological, non-genetic manipulation that the circadian system is far more flexible than previously thought. These findings challenge the current conception of entrainment and its underlying principles, and reveal new potential targets for circadian interventions.

  3. Forecasting Inundation from Debris Flows That Grow By Entraining Sediment

    Science.gov (United States)

    Reid, M. E.; Coe, J. A.; Brien, D. L.

    2014-12-01

    Destructive debris flows often grow, and extend their runouts, by entraining sediment as they travel. However, incorporating varied entrainment processes into physics-based flow routing models is challenging. As an alternative, we developed a relatively simple, automated method for forecasting the inundation hazards posed by debris flows that entrain sediment and coalesce from multiple flows. Within a drainage network, we amalgamate the effects of many possible debris flows with each flow volume proportional to an entrainment rate scaled by the upslope contributing area, and then use these volumes in the USGS GIS-based inundation model LAHARZ. Our approach only requires estimates of two parameters: spatial entrainment rate & maximum entrainment area or maximum volume. Our procedure readily integrates various sediment sources and it can portray different inundation hazard levels on a GIS-based map by varying our two parameters. We applied this approach to part of the Coast Range, southern Oregon, USA. Using aerial photography, we mapped debris flows triggered by a large 1996 rain event on a LiDAR-derived topographic base, and identified initiation locations, travel paths, and areas of channel erosion and deposition. Many catchments experienced multiple debris flows that coalesced downstream and about 95% of the debris flows entrained sediment as they traveled. Flows typically stopped entraining sediment before the upslope contributing area reached ~500,000 m2. We used pre- and post-debris-flow stereo photos to estimate spatial entrainment rates in four clear-cut catchments having both channel erosion and coalescence of flows; these rates varied from 0.12 to 0.2 m3/m2. GIS-based inundation maps, using our automated methods, are quite similar to the mapped flow paths and deposits. Given appropriate parameters, our approach could be applied to a variety of steep, channelized environments where entrainment is important, such as alpine and post-wildfire slopes.

  4. Convertisseur DC-DC à transistors GaN entrelacé couplé par TICs monolithiques frittés par SPS

    OpenAIRE

    Mercier, Adrien; Adam, Fabien; Labrousse, Denis; Revol, Bertrand; Pasko, Oleksandr; Mazaleyrat, Frederic

    2016-01-01

    International audience; Cet article présente la mise en œuvre d'un convertisseur DC-DC de type VRM fonctionnant à 2 MHz à commande entrelacée et dont les sorties sont couplées magnétiquement par TICs (Transformateurs InterCellules) monolithiques. Ces derniers ont été réalisés par frittage SPS et les procédés de fabrication sont détaillés dans cet article. Le fonctionnement haute fréquence a été permis grâce à la mise en œuvre de composants GaN.

  5. SOUDAGE D'ACIER Z 2 CN 18-10 PAR LASER CO2

    OpenAIRE

    Petesch, B.; Sakout, A.; LAURENT M.; M. Robin

    1987-01-01

    Le soudage d'un acier Z 2 CN 18 par faisceau laser a été étudié. L'influence principaux paramètres vitesse, puissance, focalisation a été examinée. Les moyens classiques de caractérisation des soudures ont été utilisées : observations métallographiques forme de la zone fondue, quantité de porosités et énergie absorbée. Le maximum de pénétration correspond au maximum d'énergie absorbée.

  6. De la démarche de conception d'un dispositif de sensibilisation à l'entrepreneuriat

    OpenAIRE

    Chené, Emmanuel; Schieb-Bienfait, Nathalie

    2009-01-01

    Cet article est consacré à l'analyse du processus de création d'un dispositif innovant de sensibilisation à l'entrepreneuriat, dans le cadre d'une maison de l'entrepreneuriat pilotée par une université française. Après un rappel des facteurs contextuels, les modalités retenues pour le management du projet sont exposées ; puis sont abordées les questions soulevées, à partir des différentes dimensions constitutives du projet (objectifs poursuivis, public ciblé, outils et démarche proposés). Enf...

  7. Réalisation d'un logiciel de calcul d'indices de vulnérabilité.

    OpenAIRE

    Erradja, Marwane; Hafidi, Yassir

    2013-01-01

    Dans le cadre de notre deuxième année au sein de l’ISIMA, nous avons réalisé un projet proposé par l’INRA UREP intitulé : « Réalisation d'un logiciel de calcul d'indices de vulnérabilité ». L’objectif était de réaliser une application intuitive qui va permettre de calculer des indices de vulnérabilité d’agro-écosystèmes dans un contexte de changements climatiques (augmentation de la température moyenne, recrudescence des évènements extrêmes type sécheresse, …). Ce projet a été réalisé e...

  8. Voor dik & dun: de moeizame balans tussen Entertainment en Education

    NARCIS (Netherlands)

    Mutsaers, K.; Renes, R.J.; Woerkum, van C.M.J.

    2007-01-01

    This study examined the development and effects of the documentary series Voor dik & dun. The series was based on the Entertainment-Education (E&E) strategy and aimed to contribute to the prevention of overweight. Data were collected by means of three perspectives: (television- and health ed

  9. DunHuang Patterns Highlights in Home Texitle Fair

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    DunHuang grotto art is world known for its fine mural paintings and its always a inspiration for designers.In this Shanghai Home Textile Fair,China Dunhuang Grotto Art Protection and Research Fund took Dunhuang classic patterns into this show and exhibited those delicate textures to the home textile industry.

  10. Dans la peau d'un chercheur 2015: the conference

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    About 100 students from 4 local classes who have participated to the 2015 edition of "Dans la peau d'un chercheur" (Being a researcher) come to CERN to see physics demonstrations and share their experiments and discoveries with other students.

  11. Evaluation concurentielle du torseur de contact pneumatique/chaussée au moyen d'une roue dynamométrique et d'un système intégré à l'infrastructure routière

    OpenAIRE

    Coiret, Alex; Orfila, Olivier

    2008-01-01

    La connaissance des efforts exercés par les roues d'un véhicule sur une chaussée facilite l'évaluation des risques de perte de contrôle. En particulier, pour des études expérimentales, de tels efforts mesurés peuvent être rapportés aux dérives des pneumatiques pour consolider l'analyse du comportement dynamique d'un véhicule. Face aux coûteuses roues dynamométriques traditionnellement employées pour cela, un système alternatif a été développé au lcpc. Constitué d'un élément de chaussée instru...

  12. Evaluation concurrentielle du torseur de contact pneumatique/chaussée au moyen d'une roue dynamométrique et d'un système intégré à l'infrastructure routière

    OpenAIRE

    Coiret, Alex; Orfila, Olivier

    2008-01-01

    La connaissance des efforts exercés par les roues d'un véhicule sur une chaussée facilite l'évaluation des risques de perte de contrôle. En particulier, pour des études expérimentales, de tels efforts mesurés peuvent être rapportés aux dérives des pneumatiques pour consolider l'analyse du comportement dynamique d'un véhicule. Face aux coûteuses roues dynamométriques traditionnellement employées pour cela, un système alternatif a été développé au lcpc. Constitué d'un élément de chauss...

  13. Convection mixte lors de l'écoulement d'un fluide de Bingham au sein d'une conduite cylindrique horizontale

    Directory of Open Access Journals (Sweden)

    N. LABSI

    2015-03-01

    Full Text Available La présente étude traite du transfert thermique en mode de convection mixte lors de l'écoulement d'un fluide viscoplastique de Bingham au sein d'une conduite cylindrique horizontale à section droite circulaire, maintenue à température constante et uniforme. Le travail numérique, basé sur la méthode des volumes finis, se focalise sur l'impact de l'intensité des forces de poussée sur le comportement hydrodynamique et thermique de l'écoulement. Les résultats montrent que la structure de l'écoulement se modifie avec l'augmentation du nombre de Grashof. Cette augmentation entraine l'amélioration du transfert thermique et l'augmentation de a perte de charge et ce, dans la zone intermédiaire de la conduite.

  14. Developpement d'algorithmes de reconstruction statistique appliques en tomographie rayons-X assistee par ordinateur

    Science.gov (United States)

    Thibaudeau, Christian

    La tomodensitometrie (TDM) permet d'obtenir, et ce de facon non invasive, une image tridimensionnelle de l'anatomie interne d'un sujet. Elle constitue l'evolution logique de la radiographie et permet l'observation d'un volume sous differents plans (sagittal, coronal, axial ou n'importe quel autre plan). La TDM peut avantageusement completer la tomographie d'emission par positrons (TEP), un outil de predilection utilise en recherche biomedicale et pour le diagnostic du cancer. La TEP fournit une information fonctionnelle, physiologique et metabolique, permettant la localisation et la quantification de radiotraceurs a l'interieur du corps humain. Cette derniere possede une sensibilite inegalee, mais peut neanmoins souffrir d'une faible resolution spatiale et d'un manque de repere anatomique selon le radiotraceur utilise. La combinaison, ou fusion, des images TEP et TDM permet d'obtenir cette localisation anatomique de la distribution du radiotraceur. L'image TDM represente une carte de l'attenuation subie par les rayons-X lors de leur passage a travers les tissus. Elle permet donc aussi d'ameliorer la quantification de l'image TEP en offrant la possibilite de corriger pour l'attenuation. L'image TDM s'obtient par la transformation de profils d'attenuation en une image cartesienne pouvant etre interpretee par l'humain. Si la qualite de cette image est fortement influencee par les performances de l'appareil, elle depend aussi grandement de la capacite de l'algorithme de reconstruction a obtenir une representation fidele du milieu image. Les techniques de reconstruction standards, basees sur la retroprojection filtree (FBP, filtered back-projection), reposent sur un modele mathematiquement parfait de la geometrie d'acquisition. Une alternative a cette methode etalon est appelee reconstruction statistique, ou iterative. Elle permet d'obtenir de meilleurs resultats en presence de bruit ou d'une quantite limitee d'information et peut virtuellement s'adapter a toutes formes

  15. Caractérisation non destructive par courants de Foucault de l'état de contraintes dans les matériaux magnétiques

    OpenAIRE

    DAHIA, Abla; Berthelot, Eric; Le Bihan, Yann; DANIEL, Laurent

    2014-01-01

    L'objectif de ce travail est d'étudier une technique de caractérisation de l'état de contraintes dans les matériaux magnétiques par la méthode du contrôle non destructif par courants de Foucault. Cette technique exploite l'effet de la contrainte sur le comportement magnétique d'un matériau magnétique. Un modèle multi-échelle a été utilisé pour décrire le comportement magnétique d'un matériau magnétique soumis à une contrainte mécanique. Un modèle éléments finis 3D a été développé pour modélis...

  16. Experimental study of gas entrainment from surface swirl

    Energy Technology Data Exchange (ETDEWEB)

    Moudjed, B., E-mail: brahim.moudjed@cea.fr; Excoffon, J.; Riva, R.; Rossi, L., E-mail: lionel.rossi@cea.fr

    2016-12-15

    Gas entrainment from surface swirls is characterized using water experiments. A free surface shear flow is generated in an open channel flow. A suction nozzle is set at the bottom of the test section to induce a downward flow and provoke gas entrainment. An important originality of these experiments is the possibility to change the inlet condition so as to generate different turbulent shear flows. This is done by adding obstacles of different sizes and shapes at the end of a flat plate separating the inlet flow from a “stagnant” water area. Velocity fields and profiles, measured with the PIV technique, are provided both to describe the inlet conditions corresponding to various geometries and flow rates, and to characterize the temporal average shear flow generated within the centre part of the channel. Gas entrainment mappings are established from direct observations of the different flow configurations. These new results show that the threshold for the suction velocities required to entrain gas are similar for the configurations with small obstacles and the flat plate configuration triggering a standard shear flow. Increasing the size of the obstacles promotes gas entrainment and reduces the threshold values of the suction velocity to trigger gas entrainment. Shadowgraphy with image processing is used to present new results characterizing the geometrical properties of surface swirls and the quantity of gas entrained. Inlet configurations with obstacles generate larger surface swirls which move upstream from the suction nozzle centre whereas they are situated downstream with the flat plate configuration. Moreover, dimensionless power laws are found to be good approximations for the surface swirl width and the quantity of gas entrained. In addition to provide new insights about gas entrainment in analytical configurations relevant to Sodium cooled fast nuclear reactor, these results should provide different test cases for the validation of MCFD codes.

  17. Etude par spectroscopie de Coulomb de points quantiques lateraux individuels et couples

    Science.gov (United States)

    Pioro-Ladriere, Michel

    Des points quantiques contenant un nombre discret et variable d'electrons sont formes dans un gaz bi-dimensionnel d'electrons a l'aide de grilles metalliques. Le transport electrique, le blocage de spin et la detection de charge sont employes comme outils spectroscopiques permettant de sonder les proprietes de ces nanostructures. Ces techniques permettent aussi de controler exactement le nombres d'electrons confines dans des points quantiques individuels et couples en utilisant un patron de grille judicieux. Une technique de refroidissement en tension est developpee afin de minimiser les effets parasites du bruit telegraphique. Ce type de bruit de charge deteriore la stabilite des nanostructures laterales par l'activation d'un minuscule courant de fuite entre les grilles et le gaz bi-dimensionnel. Un modele expliquant le role du refroidissement en tension sur le courant de fuite est presente. L'activation du courant de fuite est confirmee par detection de charge. Les effets des interactions entre les electrons pieges dans un point quantique sont ensuite etudies dans un regime ou il est possible de comparer les resulats experimentaux avec ceux obtenus par diagonalisation exacte. L'etude demontre que la phase associee au facteur de remplissage nu = 2 est instable au-dessus d'un nombre critique d'electrons. Cette instabilite est confirmee experimentalement par blocage de spin. On demontre aussi l'existence d'etats correles dans le regime des renversements de spin, associe au passage de la phase nu = 2 a nu = 1. Les etats correles sont identifies par spectroscopie en transport non lineaire. Cette caracterisation du diagramme de phase de points individuels permet de coupler deux points quantiques configures a nu = 2. Pour ce regime, la nanostructure se comporte comme un systeme a deux niveaux pouvant contenir entre un et quatre electrons de valence et ce, meme si le nombre total d'electrons est plus eleve. Les degres de liberte de charge et de spin des deux points

  18. On the maximum grain size entrained by photoevaporative winds

    CERN Document Server

    Hutchison, Mark A; Maddison, Sarah T

    2016-01-01

    We model the behaviour of dust grains entrained by photoevaporation-driven winds from protoplanetary discs assuming a non-rotating, plane-parallel disc. We obtain an analytic expression for the maximum entrainable grain size in extreme-UV radiation-driven winds, which we demonstrate to be proportional to the mass loss rate of the disc. When compared with our hydrodynamic simulations, the model reproduces almost all of the wind properties for the gas and dust. In typical turbulent discs, the entrained grain sizes in the wind are smaller than the theoretical maximum everywhere but the inner disc due to dust settling.

  19. Modeling air entrainment in plunging jet using 3DYNAFS

    OpenAIRE

    HSIAO, Chao-Tsung; Ma, Jingsen; Wu, Xiongjun; Chahine, Georges L.

    2011-01-01

    As the liquid jet plunges into a free surface, significant air is entrained into the water and forms air pockets. These air pockets eventually break up into small bubbles, which travel downstream to form a bubbly wake. To better understand the underlying flow physics involved in the bubble entrainment, in the linked videos, air entrainment due to a water jet plunging onto a pool of stationary water was numerically studied by using the 3DYNAFS software suit. The flow field is simulated by dire...

  20. Maximal air bubble entrainment at liquid drop impact

    CERN Document Server

    Bouwhuis, Wilco; Tran, Tuan; Keij, Diederik L; Winkels, Koen G; Peters, Ivo R; van der Meer, Devaraj; Sun, Chao; Snoeijer, Jacco H; Lohse, Detlef

    2012-01-01

    At impact of a liquid drop on a solid surface an air bubble can be entrapped. Here we show that two competing effects minimize the (relative) size of this entrained air bubble: For large drop impact velocity and large droplets the inertia of the liquid flattens the entrained bubble, whereas for small impact velocity and small droplets capillary forces minimize the entrained bubble. However, we demonstrate experimentally, theoretically, and numerically that in between there is an optimum, leading to maximal air bubble entrapment. Our results have a strong bearing on various applications in printing technology, microelectronics, immersion lithography, diagnostics, or agriculture.

  1. Rhythm as an affordance for the entrainment of movement.

    Science.gov (United States)

    Cummins, Fred

    2009-01-01

    A general account of rhythm in human behaviour is provided, according to which rhythm inheres in the affordance that a signal provides for the entrainment of movement on the part of a perceiver. This generic account is supported by an explication of the central concepts of affordance and entrainment. When viewed in this light, rhythm appears as the correct explanandum to account for coordinated behaviour in a wide variety of situations, including such core senses as dance and the production of music. Speech may appear to be only marginally rhythmical under such an account, but several experimental studies reveal that speech, too, has the potential to entrain movement.

  2. Caracterisation environnementale des emissions atmospheriques d'une source fixe et creation d'un outil de gestion dynamique =

    Science.gov (United States)

    Fournier, Marie-Claude

    Une caracterisation des emissions atmospheriques provenant des sources fixes en operation, alimentees au gaz et a l'huile legere, a ete conduite aux installations visees des sites no.1 et no.2. La caracterisation et les calculs theoriques des emissions atmospheriques aux installations des sites no.1 et no.2 presentent des resultats qui sont en dessous des valeurs reglementaires pour des conditions d'operation normales en periode hivernale et par consequent, a de plus fortes demandes energetiques. Ainsi, pour une demande energetique plus basse, le taux de contaminants dans les emissions atmospheriques pourrait egalement etre en dessous des reglementations municipales et provinciales en vigueur. Dans la perspective d'une nouvelle reglementation provinciale, dont les termes sont discutes depuis 2005, il serait souhaitable que le proprietaire des infrastructures visees participe aux echanges avec le Ministere du Developpement Durable, de l'Environnement et des Parcs (MDDEP) du Quebec. En effet, meme si le principe de droit acquis permettrait d'eviter d'etre assujetti a la nouvelle reglementation, l'application de ce type de principe ne s'inscrit pas dans ceux d'un developpement durable. L'âge avance des installations etudiees implique la planification d'un entretien rigoureux afin d'assurer les conditions optimales de combustion en fonction du type de combustible. Des tests de combustion sur une base reguliere sont donc recommandes. Afin de supporter le processus de suivi et d'evaluation de la performance environnementale des sources fixes, un outil d'aide a la gestion de l'information environnementale a ete developpe. Dans ce contexte, la poursuite du developpement d'un outil d'aide a la gestion de l'information environnementale faciliterait non seulement le travail des personnes affectees aux inventaires annuels mais egalement le processus de communication entre les differents acteurs concernes tant intra- qu'inter-etablissement. Cet outil serait egalement un bon

  3. Auditory-motor entrainment in vocal mimicking species: Additional ontogenetic and phylogenetic factors.

    Science.gov (United States)

    Schachner, Adena

    2010-05-01

    We have recently found robust evidence of motor entrainment to auditory stimuli in multiple species of non-human animal, all of which were capable of vocal mimicry. In contrast, the ability remained markedly absent in many closely related species incapable of vocal mimicry. This suggests that vocal mimicry may be a necessary precondition for entrainment. However, within the vocal mimicking species, entrainment appeared non-randomly, suggesting that other components besides vocal mimicry play a role in the capacity and tendency to entrain. Here we discuss potential additional factors involved in entrainment. New survey data show that both male and female parrots are able to entrain, and that the entrainment capacity appears throughout the lifespan. We suggest routes for future study of entrainment, including both developmental studies in species known to entrain and further work to detect entrainment in species not well represented in our dataset. These studies may shed light on additional factors necessary for entrainment in addition to vocal mimicry.

  4. PAR Loop Schedule Review

    Energy Technology Data Exchange (ETDEWEB)

    Schaffer, Jr.; W.F.

    1958-04-30

    The schedule for the installation of the PAR slurry loop experiment in the South Facility of the ORR has been reviewed and revised. The design, fabrications and Installation is approximately two weeks behind schedule at this time due to many factors; however, indications are that this time can be made up. Design is estimated to be 75% complete, fabrication 32% complete and installation 12% complete.

  5. Prediction inverse d'un front de solidification dans un four de transformation a haute temperature

    Science.gov (United States)

    Marois, Marc-Andre

    Ce projet de recherche porte sur une methode numerique permettant de predire l'evolution du profil 2D de la couche solide qui recouvre l'interieur des parois de plusieurs fours de transformation a haute temperature. Un modele mathematique base sur la formulation faible de l'energie est d'abord developpe et valide. Une methode de transfert thermique inverse reposant sur ce modele est ensuite developpee afin d'obtenir une mesure rapide et continue de l'evolution du profil de cette couche solide. Vu la grande inertie thermique du systeme a l'etude, differentes strategies sont proposees afin de faciliter la mise en uvre de cette methode numerique. Finalement, cette approche inverse est confrontee aux resultats experimentaux obtenus a l'aide d'un reacteur metallurgique. Une etude preliminaire montre que les fours de transformation presentent une tres grande inertie thermique qui limite grandement l'utilisation des methodes inverses. En effet, la sensibilite de cette methode numerique repose essentiellement sur le delai temporel observe entre la variation du profil du banc et la fluctuation de la temperature a la surface externe de la paroi du four. Les resultats obtenus demontrent qu'une partie de ce delai est proportionnel a la chaleur latente de fusion lorsque le materiau a changement de phase est constitue d'un melange non eutectique. Afin de limiter l'impact de ce delai temporel, deux astuces numeriques sont proposees : reutiliser plus d'une fois les mesures de temperature et modifier le probleme thermique dans les regions pateuse et liquide. D'une part, le concept de chevauchement propose permet de reduire le temps d'acquisition des donnees entre chacune des predictions. D'autre part, l'approche virtuelle developpee permet de reduire l'inertie thermique du systeme et, par le fait meme, le delai temporel associe a la diffusion de la chaleur. Ces deux strategies ont permis de predire efficacement l'evolution 1D de l'epaisseur de la couche de gelee qui se solidifie a

  6. PDF as a coupling mediator between the light-entrainable and temperature-entrainable clocks in Drosophila melanogaster.

    Science.gov (United States)

    Tomioka, K; Miyasako, Y; Umezaki, Y

    2008-01-01

    Drosophila shows bimodal circadian locomotor rhythms with peaks around light-on (morning peak) and before light-off (evening peak). The rhythm synchronizes to light and temperature cycles and the synchronization is achieved by two sets of clocks: one entrains to light cycles and the other to temperature cycles. The light-entrainable clock consists of the clock neurons located in the lateral protocerebrum (LNs) and the temperature-entrainable clock involves those located in the dorsal protocerebrum (DNs) and the cells located in the posterior lateral protocerebrum (LPNs). To understand the interaction between the light-entrainable and the temperature-entrainable clock neurons, locomotor rhythms of the mutant flies lacking PDF or PDF-positive clock neurons were examined. Under the light cycles, they showed altered phase of the evening peak. When exposed to temperature cycles of lower temperature levels, the onset of evening peak showed larger advance in contrast to those of wild-type flies. The termination of the peak also advanced while that of wild-type flies remained almost at the same phase as in the constant temperature. These results support our hypothesis that the PDF-positive light entrainable cells regulate the phase of the temperature entrainable cells to be synchronized to their own phase using PDF as a coupling mediator.

  7. Music and emotions: from enchantment to entrainment.

    Science.gov (United States)

    Vuilleumier, Patrik; Trost, Wiebke

    2015-03-01

    Producing and perceiving music engage a wide range of sensorimotor, cognitive, and emotional processes. Emotions are a central feature of the enjoyment of music, with a large variety of affective states consistently reported by people while listening to music. However, besides joy or sadness, music often elicits feelings of wonder, nostalgia, or tenderness, which do not correspond to emotion categories typically studied in neuroscience and whose neural substrates remain largely unknown. Here we review the similarities and differences in the neural substrates underlying these "complex" music-evoked emotions relative to other more "basic" emotional experiences. We suggest that these emotions emerge through a combination of activation in emotional and motivational brain systems (e.g., including reward pathways) that confer its valence to music, with activation in several other areas outside emotional systems, including motor, attention, or memory-related regions. We then discuss the neural substrates underlying the entrainment of cognitive and motor processes by music and their relation to affective experience. These effects have important implications for the potential therapeutic use of music in neurological or psychiatric diseases, particularly those associated with motor, attention, or affective disturbances. © 2015 New York Academy of Sciences.

  8. Microphysical imprint of entrainment in warm cumulus

    Directory of Open Access Journals (Sweden)

    Jennifer D. Small

    2013-07-01

    Full Text Available We analyse the cloud microphysical response to entrainment mixing in warm cumulus clouds observed from the CIRPAS Twin Otter during the GoMACCS field campaign near Houston, Texas, in summer 2006. Cloud drop size distributions and cloud liquid water contents from the Artium Flight phase-Doppler interferometer in conjunction with meteorological observations are used to investigate the degree to which inhomogeneous versus homogeneous mixing is preferred as a function of height above cloud base, distance from cloud edge and aerosol concentration. Using four complete days of data with 101 cloud penetrations (minimum 300 m in length, we find that inhomogeneous mixing primarily explains liquid water variability in these clouds. Furthermore, we show that there is a tendency for mixing to be more homogeneous towards the cloud top, which we attribute to the combination of increased turbulent kinetic energy and cloud drop size with altitude which together cause the Damköhler number to increase by a factor of between 10 and 30 from cloud base to cloud top. We also find that cloud edges appear to be air from cloud centres that have been diluted solely through inhomogeneous mixing. Theory predicts the potential for aerosol to affect mixing type via changes in drop size over the range of aerosol concentrations experienced (moderately polluted rural sites to highly polluted urban sites. However, the observations, while consistent with this hypothesis, do not show a statistically significant effect of aerosol on mixing type.

  9. Organic Entrainment and Preservation in Volcanic Glasses

    Science.gov (United States)

    Wilhelm, Mary Beth; Ojha, Lujendra; Brunner, Anna E.; Dufek, Josef D.; Wray, James Joseph

    2014-01-01

    Unaltered pyroclastic deposits have previously been deemed to have "low" potential for the formation, concentration and preservation of organic material on the Martian surface. Yet volcanic glasses that have solidified very quickly after an eruption may be good candidates for containment and preservation of refractory organic material that existed in a biologic system pre-eruption due to their impermeability and ability to attenuate UV radiation. Analysis using NanoSIMS of volcanic glass could then be performed to both deduce carbon isotope ratios that indicate biologic origin and confirm entrainment during eruption. Terrestrial contamination is one of the biggest barriers to definitive Martian organic identification in soil and rock samples. While there is a greater potential to concentrate organics in sedimentary strata, volcanic glasses may better encapsulate and preserve organics over long time scales, and are widespread on Mars. If volcanic glass from many sites on Earth could be shown to contain biologically derived organics from the original environment, there could be significant implications for the search for biomarkers in ancient Martian environments.

  10. Technical review of entrained design report

    Energy Technology Data Exchange (ETDEWEB)

    Bowser, R.P.; Clark, W.B.; Griffin, J.F.; Kesling, W.E.; Kissner, T.J.; Krach, F.G.; Metcalf, L.W.; Park, W.K.; Wurstner, R.P.

    1979-12-14

    Morgantown Energy Technology Center (METC) is planning to expand its in-house coal gasification R&D capabilities by installing a research facility that can address a number of concepts including entrained, fluid bed, and catalytic gasification and flash pyrolysis. This Advanced Gasification Concepts (AGC) facility design, as it currently stands, includes piping and instrumentation diagrams, vessel drawings and specifications, instrumentation lists and specifications, and equipment layout and isometric drawings. Before the design is finalized, a critique is needed to ensure that the intended flexibility and objectives can be met. The design approach was evaluated to determine whether the present design will meet the research objectives, including the need for flexibility. Heat and material balances, critical velocity requirements, vessel arrangements, potential operational problems, and instrumentation were reviewed. The mechanical design review included a critique of the drawings and specifications, adherence to standards and codes, materials of construction, vessels, piping, valves, heaters, and fittings. In addition, utilities requirements, heat transfer and particulate removal calculations, and pumping and heat exchanger requirements were checked. An evaluation of the equipment cost includes a critique of the reliability of the equipment cost breakdown, the areas of cost uncertainty, and the areas for potential cost savings. A safety analysis is also provided.

  11. Granular motions near the threshold of entrainment

    Science.gov (United States)

    Valyrakis, Manousos; Alexakis, athanasios-Theodosios

    2016-04-01

    Our society is continuously impacted by significant weather events many times resulting in catastrophes that interrupt our normal way of life. In the context of climate change and increasing urbanisation these "extreme" hydrologic events are intensified both in magnitude and frequency, inducing costs of the order of billions of pounds. The vast majority of such costs and impacts (even more to developed societies) are due to water related catastrophes such as the geomorphic action of flowing water (including scouring of critical infrastructure, bed and bank destabilisation) and flooding. New tools and radically novel concepts are in need, to enable our society becoming more resilient. This presentation, emphasises the utility of inertial sensors in gaining new insights on the interaction of flow hydrodynamics with the granular surface at the particle scale and for near threshold flow conditions. In particular, new designs of the "smart-sphere" device are discussed with focus on the purpose specific sets of flume experiments, designed to identify the exact response of the particle resting at the bed surface for various below, near and above threshold flow conditions. New sets of measurements are presented for particle entrainment from a Lagrangian viewpoint. Further to finding direct application in addressing real world challenges in the water sector, it is shown that such novel sensor systems can also help the research community (both experimentalists and computational modellers) gain a better insight on the underlying processes governing granular dynamics.

  12. A comparative efficacy study of photic driving brainwave entrainment technology with a novel form of more direct entrainment

    Science.gov (United States)

    Knowles, Richard Thomas

    This exploratory study compared the efficacy of a novel brainwave electromagnetic (EM) entrainment technology against a more conventional technology utilizing the photic-driving technique. Both experimental conditions were also compared with a 7-minute control session that took place immediately before each stimulation session. The Schumann Resonance (SR) frequency was selected as the delivery signal and was chosen because of previous findings suggesting that entrainment to this frequency can often produce transpersonal if not paranormal, experiences in the entrainee, which sometimes resemble remote viewing or out-of-body experiences. A pilot study determined which of two novel entrainment modalities (a copper coil or a 16-solenoid headset) worked most effectively for use with the rest of the study. In the main study, an artificial SR signal at 7.8Hz was delivered during the photic-driving sessions, but a recording of the real-time SR was used to deliver the entrainment signal during sessions devoted to the electromagnetic entrainment modality. Sixteen participants were recruited from the local area, and EEG recordings were acquired via a 32-channel Deymed electroencephalography system. Comparative analyses were performed between the control and experimental portions of each session to assess for efficacy of the novel entrainment modality used, and, in the main study, between the electromagnetic and photic-driving sessions, to assess for differential entrainment efficacy between these groups. A follow-up study was additionally performed primarily to determine whether responders could replicate their entrainment effect from the main study. Results showed that EM entrainment appeared to be possible but is not nearly as robust or reliable as photic driving. Additionally, no profound transpersonal or paranormal experiences were elicited during the course of the study, and, when asked, participants were not able to determine with any degree of success, when the

  13. La pelade par plaques

    Science.gov (United States)

    Spano, Frank; Donovan, Jeff C.

    2015-01-01

    Résumé Objectif Présenter aux médecins de famille des renseignements de base pour faire comprendre les schémas thérapeutiques et les résultats des traitements pour la pelade par plaques, de même que les aider à identifier les patients pour qui une demande de consultation en dermatologie pourrait s’imposer. Sources des données Une recension a été effectuée dans PubMed pour trouver des articles pertinents concernant le traitement de la pelade par plaques. Message principal La pelade par plaques est une forme auto-immune de perte pileuse qui touche à la fois les enfants et les adultes. Même s’il n’y a pas de mortalité associée à la maladie, la morbidité découlant des effets psychologiques de la perte des cheveux peut être dévastatrice. Lorsque la pelade par plaques et le sous-type de la maladie sont identifiés, un schéma thérapeutique approprié peut être amorcé pour aider à arrêter la chute des cheveux et possiblement faire commencer la repousse. Les traitements de première intention sont la triamcinolone intralésionnelle avec des corticostéroïdes topiques ou du minoxidil ou les 2. Les médecins de famille peuvent prescrire ces traitements en toute sécurité et amorcer ces thérapies. Les cas plus avancés ou réfractaires pourraient avoir besoin de diphénylcyclopropénone topique ou d’anthraline topique. On peut traiter la perte de cils avec des analogues de la prostaglandine. Les personnes ayant subi une perte de cheveux abondante peuvent recourir à des options de camouflage ou à des prothèses capillaires. Il est important de surveiller les troubles psychiatriques en raison des effets psychologiques profonds de la perte de cheveux. Conclusion Les médecins de famille verront de nombreux patients qui perdent leurs cheveux. La reconnaissance de la pelade par plaques et la compréhension du processus pathologique sous-jacent permettent d’amorcer un schéma thérapeutique approprié. Les cas plus graves ou r

  14. Analyse de la qualité de l'énergie électrique par le vecteur d'espace

    OpenAIRE

    Ignatova, Vanya; Granjon, Pierre; Bacha, Seddik

    2006-01-01

    National audience; Une nouvelle technique pour l'analyse des problèmes de qualité de l'énergie électrique est présentée dans cet article. Elle est basée sur la transformation du vecteur d'espace, qui décrit un système triphasé par une grandeur complexe - le vecteur d'espace, et une grandeur réelle – la composante homopolaire. En effet, dans le cas d'un système triphasé non perturbé, la composante homopolaire est nulle et le vecteur d'espace prend la forme d'un cercle dans le plan complexe. To...

  15. Study of Air Entrainment by a Horizontal Plunging Liquid Jet

    Science.gov (United States)

    Trujillo, Mario; Deshpande, Suraj; Wu, Xiongjun; Chahine, Georges

    2009-11-01

    The process of air entrainment following the impact of an initially horizontal circular water jet on a pool of water has been studied computationally and experimentally. It has been found that the entrainment of air cavities in the near field region is periodic, not continuous as reported in earlier studies. The simulations are based on a Volume-of-Fluid methodology with interfacial compression using a modified version of the open source utilities, OpenFoam. Close agreement with experiments is reported on the creation of cavities in the near field, where air entrainment occurs. The period of entrainment is found to be proportional to g, and a simplified closed-form solution for this periodic event is presented. An overall physical picture of the mechanisms leading to bubble formation is given. The far field, which is characterized by the presence of small bubbles is only partially resolved computationally. Comparisons against velocity data are performed in this region leading to adequate qualitative agreement.

  16. Entrainment of a Synthetic Oscillator through Queueing Coupling

    Science.gov (United States)

    Hochendoner, Philip; Mather, William; Butzin, Nicholas; Ogle, Curtis

    2014-03-01

    Many biological systems naturally exhibit (often noisy) oscillatory patterns that are capable of being entrained by external stimuli, though the mechanism of entrainment is typically obscured by the complexity of native networks. A synthetic biology approach, where genetic programs are wired ``by hand,'' has proven useful in this regard. In the present study, we use a synthetic oscillator in Escherichia coli to demonstrate a novel and potentially widespread mechanism for biological entrainment: competition of proteins for degradation by common pathway, i.e. a entrainment by a bottleneck. To faithfully represent the discrete and stochastic nature of this bottleneck, we leverage results from a recent biological queueing theory, where in particular, the queueing theoretic concept of workload is discovered to simplify the analysis. NSF Award 1330180.

  17. Flicker regularity is crucial for entrainment of alpha oscillations

    Directory of Open Access Journals (Sweden)

    Annika Notbohm

    2016-10-01

    Full Text Available Previous studies have shown that alpha oscillations (8-13 Hz in human electroencephalogram (EEG modulate perception via phase-dependent inhibition. If entrained to an external driving force, inhibition maxima and minima of the oscillation appear more distinct in time and make potential phase-dependent perception predictable.There is an ongoing debate about whether visual stimulation is suitable to entrain alpha oscillations. On the one hand, it has been argued that a series of light flashes results in transient event-related responses (ERPs superimposed on the ongoing EEG. On the other hand, it has been demonstrated that alpha oscillations become entrained to a series of light flashes if they are presented at a certain temporal regularity. This raises the question under which circumstances a sequence of light flashes causes entrainment, i.e. whether an arrhythmic stream of light flashes would also result in entrainment.Here, we measured detection rates in response to visual targets at two opposing stimulation phases during rhythmic and arrhythmic light stimulation. We introduce a new measure called ‘behavioral modulation depth’ to determine differences in perception. This measure is capable of correcting for inevitable artifacts that occur in visual detection tasks during visual stimulation. The physical concept of entrainment predicts that increased stimulation intensity should produce stronger entrainment. Thus, two experiments with medium (Experiment 1 and high (Experiment 2 stimulation intensity were performed. Data from the first experiment show that the behavioral modulation depth (alpha phase-dependent differences in detection threshold increases with increasing entrainment of alpha oscillations. Furthermore, individual alpha phase delays of entrained alpha oscillations determine the behavioral modulation depth: the largest behavioral modulation depth can be found if targets presented during the minimum of the entrained oscillation

  18. Modeling and simulation of an entrained flow coal gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Govind, R.; Shah, J.

    1984-01-01

    A mathematical model has been developed to simulate the Texaco downflow entrained-bed pilot-plant gasifier using coal liquefaction residues and coal-water slurries as feedstocks. This model describes the physical and chemical processes occurring in an entrained coal gasifier. Parameter studies were made in order to provide a better understanding of the reactor performance for various inlet feed conditions utilising the model.

  19. Differential entrainment of neuroelectric delta oscillations in developmental dyslexia.

    Directory of Open Access Journals (Sweden)

    Fruzsina Soltész

    Full Text Available Oscillatory entrainment to the speech signal is important for language processing, but has not yet been studied in developmental disorders of language. Developmental dyslexia, a difficulty in acquiring efficient reading skills linked to difficulties with phonology (the sound structure of language, has been associated with behavioural entrainment deficits. It has been proposed that the phonological 'deficit' that characterises dyslexia across languages is related to impaired auditory entrainment to speech at lower frequencies via neuroelectric oscillations (<10 Hz, 'temporal sampling theory'. Impaired entrainment to temporal modulations at lower frequencies would affect the recovery of the prosodic and syllabic structure of speech. Here we investigated event-related oscillatory EEG activity and contingent negative variation (CNV to auditory rhythmic tone streams delivered at frequencies within the delta band (2 Hz, 1.5 Hz, relevant to sampling stressed syllables in speech. Given prior behavioural entrainment findings at these rates, we predicted functionally atypical entrainment of delta oscillations in dyslexia. Participants performed a rhythmic expectancy task, detecting occasional white noise targets interspersed with tones occurring regularly at rates of 2 Hz or 1.5 Hz. Both groups showed significant entrainment of delta oscillations to the rhythmic stimulus stream, however the strength of inter-trial delta phase coherence (ITC, 'phase locking' and the CNV were both significantly weaker in dyslexics, suggestive of weaker entrainment and less preparatory brain activity. Both ITC strength and CNV amplitude were significantly related to individual differences in language processing and reading. Additionally, the instantaneous phase of prestimulus delta oscillation predicted behavioural responding (response time for control participants only.

  20. Big Data et conception d'un système d'information d'aide à la décision clinique : vers une gestion sociocognicielle de la responsabilité médicale ?

    OpenAIRE

    Sybord, Christine

    2016-01-01

    International audience; Avec les défis de stockage, d'analyse, de protection des données de santé à caractère personnel posés par le Big Data, la question de l'évaluation d'un Système (d'information) d'Aide à la Décision Médicale (SADM) devient cruciale autant pour le médecin que pour le patient. Dans ces conditions, l'article aborde la conception d'un SADM en questionnant ses conditions d'intégration dans les pratiques médicales de la décision clinique. La première partie, après avoir caract...

  1. Optimisation 3D du nez d'un SuperSonic Business Jet basée sur l'adaptation de maillages. Application à la réduction du bang sonique

    OpenAIRE

    Alauzet, Frédéric; Mohammadi, Bijan

    2003-01-01

    Ce rapport traite d'un problème d'optimisation de forme 3D du nez d'un SuperSonic Business Jet (SSBJ) sous des contraintes aérodynamiques et accoustiques. La contrainte accoustique concerne la génération du bang sonique par l'avion. On présente une méthode d'optimisation de faible dimension pour analyser l'impact du nez sur ces contraintes. Plus précisément, après avoir paramétrisé le nez de l'avion, on échantillonne l'espace de contrôle, puis on construit la surface de réponse qui nous donne...

  2. MESURE NON INVASIVE DU DÉBIT AORTIQUE PAR VOIE OESOPHAGIÈNNE

    OpenAIRE

    Lavandier, B.; Cathignol, D.; Muchada, R.; Fady, J.; Birer, A.

    1990-01-01

    Depuis plusieurs années nous avons montré la faisabilité et l'intérêt clinique de la débitmétrie aortique par voie oesophagienne. Une amélioration importante de cette méthode a été apportée par le développement d'un nouveau type de débitmètre associant un imageur T.M. et un vélocimètre Doppler à émission pulsée. Afin de pouvoir mesurer simultanément et de façon continue le diamètre de l'aorte et la vitesse du flux sanguin aussi bien chez l'adulte que chez l'enfant (à l'aide d'une sonde oesoph...

  3. Entrainment of Activation during Ventricular Fibrillation (VF) by Distributed Pacing.

    Science.gov (United States)

    Gu, Yiping; Moghe, Sachin; Patwardhan, Abhijit

    2002-03-01

    Optical mapping and pacing studies show excitable gaps during VF. This observation supports entrainment of activation by spatially distributed pacing. Such pacing approach would be enhanced by availability of an index of spatio-temporal heterogeneity in activation. We use simulations to demonstrate feasibility of entraining activations and of using spatially averaged coherence as an index of uniformity in activation. We used a Luo-Rudy model to simulate VF in a matrix of 400x400 cells. Stimuli were delivered from 8 rows of electrodes. Trans-membrane voltages from nine locations spanning the entrained area were used to compute 6 time-coherencies. Average of 6 coherencies was used as an index of uniformity of activations. Results showed that when stimuli were delivered at cycle lengths slightly shorter than intrinsic activation intervals, activations during VF could be entrained into a planar pattern. As expected, average coherence was low during native VF and increased during entrainment. Thus, distributed pacing and time-coherence may be used to entrain and modify activation during VF.

  4. Entrainment Characteristics for variable-angle plunging liquid jets

    Science.gov (United States)

    Deshpande, Suraj; Trujillo, Mario

    2013-11-01

    Simulations based on an algebraic VoF method are used to study the entrainment characteristics of a water jet plunging into a quiescent pool at angles ranging from 10 to 90 deg. with pool. Our previous study of shallow plunging jets (Deshpande et al. 2012) revealed a discernible frequency in the formation of large air cavities. This contrasts the well-documented chaotic entrainment at steeper inclinations, suggesting a different entrainment mechanism exists for shallow angles. Quantitatively, it is found that larger cavities and greater volume of entrained air occur at shallower angles (10, 12 deg.). A precursor to the formation of these large cavities is the presence of a stagnation region in the zone of impingement. Using a local mass and momentum balance, we show that this stagnation region deflects the incoming jet at wide angles producing large air cavities. Entrainment in shallow jets is similar to the initial impact of the jet with a pool, but it occurs periodically. The recurrence is a consequence of jet disruption by traveling waves on the pool. Qualitative analysis, supported with simulations, demonstrates linear scaling of entrainment period with Froude number.

  5. Rhythmic entrainment as a musical affect induction mechanism.

    Science.gov (United States)

    J Trost, W; Labbé, C; Grandjean, D

    2017-02-01

    One especially important feature of metrical music is that it contains periodicities that listeners' bodily rhythms can adapt to. Recent psychological frameworks have introduced the notion of rhythmic entrainment, among other mechanisms, as an emotion induction principle. In this review paper, we discuss rhythmic entrainment as an affect induction mechanism by differentiating four levels of entrainment in humans-perceptual, autonomic physiological, motor, and social-all of which could contribute to a subjective feeling component. We review the theoretical and empirical literature on rhythmic entrainment to music that supports the existence of these different levels of entrainment by describing the phenomena and characterizing the associated underlying brain processes. The goal of this review is to present the theoretical implications and empirical findings about rhythmic entrainment as an important principle at the basis of affect induction via music, since it rests upon the temporal dimension of music, which is a specificity of music as an affective stimulus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Dispositif de collaboration entre futurs enseignants de maternelle et du secondaire supérieur en vue d'améliorer la maîtrise des concepts scientifiques à enseigner dans le cadre d'une approche par compétence

    OpenAIRE

    Poffé, Corentin; Doyen, Dominique; Hindryckx, Marie-Noëlle

    2013-01-01

    Description d'un dispositif de collaboration entre deux institutions de formation des maitres afin d'améliorer la maitrise des concepts scientifiques dans le cadre d'une approche par compétences. Mise en place et évolution de la collaboration.

  7. Comparaison de diverses méthodes de dosage des argiles d'un sable de gisement. Dosage des argiles Comparison of Different Methods of Determining Clays in a Reservoir Sand. Quantitative Analysis of Clays

    OpenAIRE

    Yvon J.; Baudracco J.; Letellier M. C.

    2006-01-01

    Les argiles d'un sable de gisement, concentrées dans la fraction de diamètre Phi < 40µm, ont été dosées par trois procédés différents : - un ensemble de méthodes dites classiquesretenues par Dejou et al (1977) reposant sur les analyses chimiques et thermopondérales; - une méthode mise au point au laboratoire qui donne la teneur globale en argiles après déduction des proportions de majeurs non argileux : le quartz étant dosé par diffraction X et la jarosite calculée à partir de la teneur en so...

  8. L'apport d'un glossaire juridique

    OpenAIRE

    2014-01-01

    Le présent travail vise à obtenir une réponse à la problématique suivante : Quel est l'apport d'un glossaire juridique élaboré à partir de textes traduits au cours d'une formation de traduction juridique? Peut-il être utile à des étudiants débutant ladite formation ainsi qu'éventuellement à des jeunes diplômés?

  9. Developpement d'un estimateur d'etat energetique d'un chauffe-eau pour un controle par champ moyen

    Science.gov (United States)

    Solis, Jerome

    Domestic electric water heaters (EWH) provide an interesting energy storage potential that can be exploited in the context of smart grids. For example, a variation of 1 °C of the water temperature of an EWH of 270 liters corresponds to 0.313 kWh of energy. For utilities like Hydro-Quebec, which has about 2 million EWH connected to its grid, this represents a strong storage potential. This storage source already present on the network could allow, using an adequate control strategy, to smooth the electricity consumption curve by moving some of the load occurring during peak periods to trough periods. This thesis position itself in the context of developing a simulation platform to implement a mean field control strategy of water heaters on the grid. This innovative approach enables control of all water heaters to meet a global objective while respecting local constraints of each. To be functional, the strategy requires several components to be integrated into the simulation platform. Specifically, this thesis focuses on the development of a numerical model and the estimation of the state in temperature and energy of an EWH. The proposed model for predicting the behavior of a EWH is a multi-nodal model. This approach allows discretizing the tank of an EWH into smaller volumes. The energy conservation equation is solved for each of these sub-volumes and it is possible to predict changes in the output mean temperature with an average error of 2.4 °C. The results from the multi-nodal model compare favorably with numerical reference models, found in the TRNSYS thermal simulation software, as well as experimental measurements of temperature of an electric water heater. In this model, the temperature is assumed to be uniform for each sub-volume and the standby losses are considered constants. Although the model is linear, a correction routine allows redistributing adequately heat within the tank while respecting the thermal dynamics of the heater, including the presence of temperature stratification at the heating elements, hence breaking the linearity. The multi-nodal model is used primarily to simulate the load of a large water heater population on the power grid. It is also useful to the scheduler, which generates the desired temperature for the whole population, as well as by mean field controller, which generates the optimal control for this same group. The estimation process takes place in two distinct steps: estimating the sequence of hot water draw (discrete state of the system) and the reconstruction of the temperature inside the tank (continuous system state). To perform the estimation of the drawing sequence, a maximum likelihood test is used with a set of measurements of the average temperature of the system. Under the assumption that the statistics of random events, modeled by a two state Markov chain (active and inactive) are known a priori, a set of possible drawing scenarios is generated. By comparing the prediction for each scenario with the actions of the system, the one minimizing the error between the predicted and measured temperature is retained. This method predicts the discrete state of the system correctly 93.7 % of the time. Then, based on the multi-nodal model, a routine for estimating the continuous state of an EWH is developed. This model should be simplified by removing the temperature correction routine in order to keep it linear. This is required in order to build more easily a state observer, a tool that allows the full reconstruction of the temperature state from measurements. This simplification results in limiting the use of the observer to periods of drawing, because without drawing, there is no heat exchange in the system, resulting in aberrations in the simplified model. Those aberrations are corrected under the assumption that the power of the heating elements is distributed in all layers of the system in proportion to their respective volume. Each node is hence heated by an intermediate element. To realize the reconstruction of the continuous state of temperature, two different approaches are considered: the multivariate observer and the Kalman filter. With at most 3 temperature measurements, either in the highest layer of the tank, near the top heating element and the latter at the bottom of the tank of the water heater, a global average error of -440 Wh on all estimated components of the water heater state is obtained by using the multivariate observer, which translates into a global mean percentage error (MPE) of -2.9 % on the energy stocking capacity. Taking advantage of an independent use of the discrete state of the system, the Kalman filter was able to reconstruct the continuous state with a global MPE of -2.0 %, or -270 Wh. For these reasons, the Kalman filter is preferred to the multivariate observer to complete the process of estimating the complete state of the water heater. Moreover, the estimation made by the Kalman filter or the multivariate observer may deviate around +/-10-15 % compared to the total energy stored in the water heater. This thesis presents innovative tools allowing the use of a mean field control strategy in a context of smart grids. This brand new approach presents many challenges and significant improvements can be envisioned, especially for estimating the state of the water heater. Mainly, a more accurate description of the process of extracting hot water, integrating several types of different drawing intensity, allow a more accurate and robust estimation of the hot water drawing sequence.

  10. Choix et fiabilité d'un modèle de rétrocalcul des tailles en écologie halieutique. Mise au point d'un logiciel informatique

    Directory of Open Access Journals (Sweden)

    BAGLINIÈRE E.

    1990-10-01

    Full Text Available Les modèles de rétrocalcul des tailles à partir de mesures de pièces osseuses sont souvent utilisés sans précautions en dynamique des populations et en écologie halieutiques. Le choix d'un modèle doit être justifié et sa validité doit être estimée. Il a donc été développé un logiciel informatique qui permet l'ajustement des différents modèles proposés par la littérature (linéarisables et polynomiaux et le rétrocalcul des tailles par plusieurs méthodes. Ce logiciel donne aussi des critères pour sélectionner le meilleur modèle et évaluer sa fiabilité: graphes, tests permettant d'analyser la "représentativité" d'une régression, ainsi que la normalité et l'indépendance de ses résidus, intervalle de confiance des tailles rétrocalculées. Ce logiciel est testé sur une population (239 individus de juvéniles migrants de Truite de mer (Salmo trutta L piégés sur une rivière de Normandie ainsi que sur un sous-échantillon issu de cette population.

  11. Disordered Speech Disrupts Conversational Entrainment: A study of Acoustic-prosodic Entrainment and Communicative Success in Populations with Communication Challenges.

    Directory of Open Access Journals (Sweden)

    Stephanie Anna Borrie

    2015-08-01

    Full Text Available Conversational entrainment, a pervasive communication phenomenon in which dialogue partners adapt their behaviors to align more closely with one another, is considered essential for successful spoken interaction. While well-established in other disciplines, this phenomenon has received limited attention in the field of speech pathology and the study of communication breakdowns in clinical populations. The current study examined acoustic-prosodic entrainment, as well as a measure of communicative success, in three distinctly different dialogue groups: (i healthy native vs. healthy native speakers (Control, (ii healthy native vs. foreign-accented speakers (Accented, and (iii healthy native vs. dysarthric speakers (Disordered. Dialogue group comparisons revealed significant differences in how the groups entrain on particular acoustic–prosodic features, including pitch, intensity, and jitter. Most notably, the Disordered dialogues were characterized by significantly less acoustic-prosodic entrainment than the Control dialogues. Further, a positive relationship between entrainment indices and communicative success was identified. These results suggest that the study of conversational entrainment in speech pathology will have essential implications for both scientific theory and clinical application in this domain.

  12. Disordered speech disrupts conversational entrainment: a study of acoustic-prosodic entrainment and communicative success in populations with communication challenges.

    Science.gov (United States)

    Borrie, Stephanie A; Lubold, Nichola; Pon-Barry, Heather

    2015-01-01

    Conversational entrainment, a pervasive communication phenomenon in which dialogue partners adapt their behaviors to align more closely with one another, is considered essential for successful spoken interaction. While well-established in other disciplines, this phenomenon has received limited attention in the field of speech pathology and the study of communication breakdowns in clinical populations. The current study examined acoustic-prosodic entrainment, as well as a measure of communicative success, in three distinctly different dialogue groups: (i) healthy native vs. healthy native speakers (Control), (ii) healthy native vs. foreign-accented speakers (Accented), and (iii) healthy native vs. dysarthric speakers (Disordered). Dialogue group comparisons revealed significant differences in how the groups entrain on particular acoustic-prosodic features, including pitch, intensity, and jitter. Most notably, the Disordered dialogues were characterized by significantly less acoustic-prosodic entrainment than the Control dialogues. Further, a positive relationship between entrainment indices and communicative success was identified. These results suggest that the study of conversational entrainment in speech pathology will have essential implications for both scientific theory and clinical application in this domain.

  13. Parálisis cerebral :

    OpenAIRE

    Giral Lamenca, Mónica

    2015-01-01

    Se aborda el tema de la parálisis cerebral definiendo qué es, clasificando los tipos de parálisis dependiendo de la afectación y las características principales. Se explican algunos de sus tratamientos, se dan sistemas alternativos y/o aumentativos de comunicación para un alumno con PC (parálisis cerebral).

  14. Numerical study on onset of gas entrainment from free surface

    Energy Technology Data Exchange (ETDEWEB)

    Tomoaki Kunugi [Department of Nuclear engineering, Kyoto University, Yoshida Sakyou-ku Kyoto (Japan); Toshiki Ezure; Takaaki Sa ka; Kei Ito [Japan Nuclear Cycle Development Institute, 4002 Narita-cho, O-arai-cho Higashi-ibaraki-gun, 311- 1393 (Japan)

    2005-07-01

    Full text of publication follows: A fast breeder nuclear reactor (FBR) has an important role for closing a fuel cycle system in fission nuclear reactor systems. The liquid sodium cooling system of a latest compact FBR concept consists of two loops connected to a heat exchanger (HEX) and a pool-typed reactor vessel with the upper core structures (UCS). The high temperature sodium coolant comes from the reactor core to the vessel and flows through the hot legs towards the HEX. In order to design the compact FBR, it is necessary to clarify a criterion of a cover-gas entrainment from the coolant free surface of the vessel to the HEX through the hot leg. The surface velocity of the coolant in the vessel is considered as one of the key parameters of the gas entrainment phenomena: bubble entrained by free surface vortex, entraining bubbles caused by supercritical flows and gas entrainment by wave breaking. However, there is no clear quantitative explanation and criterion regarding the on-set condition of gas entrainment from the free surface until today. In the present study, numerical simulation of the gas entrainment and the bubble transport from free surface to the hot leg regarding the bubble entrainment due to the supercritical surface flows have been performed by means of the Multi-interface and Advection and Reconstruction Solver (MARS) and the numerical results are compared with that of the small scale fundamental experiments. The final goal of this study is to establish the evaluation procedure and criterion of these phenomena. Experiment performed by Moriya was chosen as the reference data for this comparison study. The test section consisted of an open-upped rectangular box with the inlet and outlet nozzles located at bottom of the box and almost a half height of the test section was filled with water. Resulting from these simulations, the gas entrainment phenomena were observed for both cases at certain flow conditions. In two-dimensional simulations, we found

  15. Modification of the cast concrete mixture by air-entraining agents

    Directory of Open Access Journals (Sweden)

    N.I. Vatin

    2015-06-01

    Full Text Available The paper investigates the combined effect of superplasticizer based on the naphthalene lignosulfonate and the air-entraining surfactant agent on the fluidity, connectivity and air entrainment of concrete. The air-entraining surfactant agent contributes significantly into air entrainment and reduces the water gain and the mortar separation. It was found that under the introduction of air-entraining surfactant agents in the concrete mixture which contains the superplasticizer, the concrete mobility decreases even though the air-entraining agent is a plasticizer itself. The introduction of 0.1 % air-entraining agent decreases mobility: slump Abrams – 5–6 %, slump flow – 18–22 %. Besides, the effect of increasing the connectivity of the concrete mix is associated with the air entrainment. Regardless of the air-entraining surfactant agent, the superplasticizer reduces water separation, and does not have an air-entraining impact, and virtually has no effect on the air entrainment caused by the addition of the air-entraining agent. With the increasing quantity of the air-entraining surfactant agent in the concrete mix, regardless of the superplasticizer dosage, the amount of the entrained air increases from 3 to 7 %, and water separation is reduced to almost 0. Thus, the synergy of the superplasticizer and the air-entraining agent was negative, but it is possible to observe a positive effect in respect of the concrete mix connectivity.

  16. Nonassociative learning promotes respiratory entrainment to mechanical ventilation.

    Directory of Open Access Journals (Sweden)

    Shawna M MacDonald

    Full Text Available BACKGROUND: Patient-ventilator synchrony is a major concern in critical care and is influenced by phasic lung-volume feedback control of the respiratory rhythm. Routine clinical application of positive end-expiratory pressure (PEEP introduces a tonic input which, if unopposed, might disrupt respiratory-ventilator entrainment through sustained activation of the vagally-mediated Hering-Breuer reflex. We suggest that this potential adverse effect may be averted by two differentiator forms of nonassociative learning (habituation and desensitization of the Hering-Breuer reflex via pontomedullary pathways. METHODOLOGY/PRINCIPAL FINDINGS: We tested these hypotheses in 17 urethane-anesthetized adult Sprague-Dawley rats under controlled mechanical ventilation. Without PEEP, phrenic discharge was entrained 1:1 to the ventilator rhythm. Application of PEEP momentarily dampened the entrainment to higher ratios but this effect was gradually adapted by nonassociative learning. Bilateral electrolytic lesions of the pneumotaxic center weakened the adaptation to PEEP, whereas sustained stimulation of the pneumotaxic center weakened the entrainment independent of PEEP. In all cases, entrainment was abolished after vagotomy. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate an important functional role for pneumotaxic desensitization and extra-pontine habituation of the Hering-Breuer reflex elicited by lung inflation: acting as buffers or high-pass filters against tonic vagal volume input, these differentiator forms of nonassociative learning help to restore respiratory-ventilator entrainment in the face of PEEP. Such central sites-specific habituation and desensitization of the Hering-Breuer reflex provide a useful experimental model of nonassociative learning in mammals that is of particular significance in understanding respiratory rhythmogenesis and coupled-oscillator entrainment mechanisms, and in the clinical management of mechanical ventilation in

  17. A droplet entrainment model for horizontal segregated flows

    Energy Technology Data Exchange (ETDEWEB)

    Höhne, Thomas, E-mail: T.Hoehne@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) – Institute of Fluid Dynamics, P.O. Box 510119, D-01314 Dresden (Germany); Hänsch, Susann [Imperial College, Department of Mechanical Engineering, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2015-05-15

    Highlights: • We further developed the flow morphology detection model AIAD. • An advanced droplet entrainment model was introduced. • The new approach is applied against HAWAC experiments. - Abstract: One limitation in simulating horizontal segregated flows is that there is no treatment of droplet formation mechanisms at wavy surfaces. For self-generating waves and slugs, the interfacial momentum exchange and the turbulence parameters have to be modeled correctly. Furthermore, understanding the mechanism of droplet entrainment for heat and mass transfer processes is of great importance in the chemical and nuclear industry. The development of general computational fluid dynamics models is an essential precondition for the application of CFD codes to the modeling of flow related phenomena. The new formulation for the interfacial drag at the free surface and turbulence parameters within the algebraic interfacial area density model (AIAD) represents one step toward a more physical description of free surface flows including less empiricism. The AIAD approach allows the use of different physical models depending on the local fluid morphology inside a macro-scale multi-fluid framework. A further step of improving the modeling of free interfaces lies within the consideration of droplet entrainment mechanisms. In this paper a new sub-grid entrainment model is proposed, which assumes that due to liquid turbulence the interface gets rough and wavy leading to the formation of droplets. Therefore, the droplet entrainment model requires the consideration of an additional droplet phase, which is described with an own set of balance equations in the spirit of the particle model. Two local key factors determine the rate of droplet entrainment: the liquid turbulent kinetic energy as well as the outward velocity gradient of the liquid relative to the interface motion. The new droplet entrainment approach is included into CFD simulations for attempting to reproduce existing

  18. Conception d'un outil d'aide a la decision de technologies de fabrication additive en milieu aeronautique

    Science.gov (United States)

    Buvat, Gael

    La fabrication additive offre une opportunite d'amelioration des methodes de productions de pieces. Cependant, les technologies de fabrication additive sont diverses, les fournisseurs de services sont multiples et peu de personnel est forme pour operer sur ces technologies. L'objectif de cette etude est d'emettre une suggestion de concepts d'outils d'aide a la decision de technologies, de materiaux et de post-traitements de fabrication additive en milieu aeronautique. Trois sous-objectifs sont employes. Premierement, la definition des criteres de decision de technologies, de materiaux et de post-traitements de fabrication additive. Ensuite, l'elaboration d'un cahier des charges de l'outil d'aide a la decision en accord avec les besoins industriels du secteur aeronautique. Et enfin, la suggestion de trois concepts d'outils d'aide a la decision et leur evaluation par comparaison au cahier des charges etabli. Les criteres captures aupres de 11 industriels concernent des criteres de couts, de qualite, de conception et de delai d'obtention. Ensuite, nous avons elabore un cahier des charges permettant de reunir les besoins des industriels du secteur aeronautique selon trois axes qui constituent la colonne vertebrale des outils d'aide a la decision : une suggestion d'interface utilisateur, une suggestion de bases de donnees et un moteur de selection des technologies, des materiaux et des post-traitements de fabrication additive. La convivialite de l'interface utilisateur, l'evaluation de la qualite souhaitee par l'utilisateur et la prise en compte des etudes de cas realisees par le moteur de selection sont exemples de besoins que nous avons identifie au sein de cette etude. Nous avons ensuite transcrit ces besoins en specifications techniques pour permettre une evaluation du niveau de satisfaction des industriels au travers d'un pointage des trois concepts suggeres. Ces trois concepts d'outils d'aide a la decision ont ete realises respectivement grâce a Microsoft Excel

  19. Entrainment Zone Characteristics and Entrainment Rates in Cloud-Topped Boundary Layers from DYCOMS-II

    Science.gov (United States)

    2012-03-01

    height hA : we A  hA t  WhA (2) where WhA is the average vertical velocity at height Ah . The downward direction will be considered...are conserved in the midst of turbulent entrainment mixing and phase change via evaporation and condensation, while w xA  hA t  WhA ...X A  we A X A AX Awx      A A A h h wx wx wx       w x  hA  w x  hA  hA t  WhA      X A  we A X A we A  w x

  20. Principe de commande numérique temps réel d'un onduleur à modulation de largeur d'impulsion sur charges non linéaires

    Science.gov (United States)

    Maussion, Pascal; Faucher, Jean; Grandpierre, Marcel

    1994-06-01

    This paper proposes a new method for the real time digital control of a P.W.M. inverter, used in U.P.S. (Uninterruptible Power Supply). The output voltage is compared to a sinusoidal reference, to compute in real time through a digital controller, the pulse width of the same interval. This strategy is verified through computer simulations and provides a very fast compensation of disturbances, caused by non linear loads such as rectifiers and triac loads, with low T.H.D. (Total Harmonic Distortion) and fondamental control. Cet article propose une méthode nouvelle et originale pour la commande numérique temps réel d'un onduleur MLI sur charges non linéaires. Un asservissement de la valeur moyenne instantanée de la tension de sortie est réalisé par l'intermédiaire d'un correcteur proportionnel dérivé et d'une boucle d'anticipation. Les variations de la charge sont prises en compte par précompensation ce qui permet d'obtenir de bons résultats vérifiés par simulation, tant pour le taux de distorsion harmonique que pour la valeur du terme fondamental.

  1. Modeling air entrainment in plunging jet using 3DYNAFS

    CERN Document Server

    Hsiao, Chao-Tsung; Wu, Xiongjun; Chahine, Georges L

    2011-01-01

    As the liquid jet plunges into a free surface, significant air is entrained into the water and forms air pockets. These air pockets eventually break up into small bubbles, which travel downstream to form a bubbly wake. To better understand the underlying flow physics involved in the bubble entrainment, in the linked videos, air entrainment due to a water jet plunging onto a pool of stationary water was numerically studied by using the 3DYNAFS software suit. The flow field is simulated by directly solving the Navier-Stokes equations through the viscous module, 3DYNAFS-VIS, using a level set method for capturing the free surface. The breakup of entrained air pockets and the resulting bubbly flow were modeled by coupling 3DYNAFS-VIS with a Lagrangian multi-bubble tracking model, 3DYNAFS-DSM (Hsiao & Chahine, 2003), which emits bubbles into the liquid according to local liquid/gas interface flow conditions based on the sub-grid air entrainment modeling proposed by Ma et al. (2011), and tracks all bubbles in t...

  2. Gas entrainment in scaled model of pool type LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, I.; Chandra, L.; Laxman, D.; Kumar, A.; Gopal, C.A.; Shivakumar, N.S.; Padmakumar, G.; Anand Babu, C.; Vaidyanathan, G. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India)

    2007-07-01

    The reactor Thermal hydraulics plays an important role for successful operation of Prototype Fast Breeder Reactor (PFBR), which is under construction at Kalpakkam, India. One of the issues to be resolved in PFBR is argon cover gas entrainment problem from free liquid sodium surface. The entrained cover gas may hinder the normal reactor operation. High free surface velocity along with the presence of various immersed components in the hot pool is the cause of gas entrainment from free surface. To reduce the free surface velocity and hence gas entrainment, ring type baffle plates were considered. Initially the optimum geometry of the baffle plate was arrived through numerical analysis using PHOENICS, a commercial computational fluid dynamics tool. Finally the experiments were conducted in a 1/4 scale water model of PFBR primary circuit with selected baffle plate geometry. It was found that a baffle plate with radial width of 125 mm in the model and located above intermediate heat exchanger is very effective to reduce the gas entrainment problem in PFBR. (authors)

  3. Droplet entrainment rate in gas-liquid annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, P. [Energy Research Inc., Rockville, Maryland (United States); Liu, Y.; Ishii, M. [Purdue Univ., West Lafayette, Indiana (United States); Mori, M. [Tokyo Electric Power Co., Inc., Yokohama (Japan); Chen, S. [Purdue Univ., West Lafayette, Indiana (United States)

    2011-07-01

    Droplet entrainment and deposition are the two most important physical phenomena in the gas-liquid annular two-phase flow. Modeling of these phenomena is essential for the estimation of dryout margins in the Light Water Reactors (LWRs) and the boilers. In this study, gas-liquid annular two-phase flow experiments are performed in a vertical round tube test section under adiabatic conditions. Air-water and organic fluid Freon-113 are used as the test fluids. The experiments covered a wide range of pressure and flow conditions. Liquid film extraction technique was used for the measurement of droplet entrainment and deposition rates. Additionally, the thickness of liquid film was measured in the air-water experiments using the ring type conductance probes. In this paper, the experimental data on entrainment rate is used to analyze the currently available correlations in the literature. The analysis showed that the existing correlations failed to predict the data at high gas velocity conditions. At high gas velocity, the experimental entrainment rate approaches a maximum limiting value; however, the correlations predicted continuously increasing entrainment rate as the gas velocity increases. (author)

  4. Experimental study of entrainment phenomenon in a trapped vortex combustor

    Institute of Scientific and Technical Information of China (English)

    Zhang Rongchun; Fan Weijun

    2013-01-01

    Trapped vortex combustor (TVC) is an advanced low-pollution gas turbine combustor,with the adoption of staged combustion technique.To achieve low-pollutant emission and better combustion performance,the proportion of the air flow in each combustion zone should be precisely determined in the design of the combustor.Due to the presence of entrainment phenomenon,the total air flow in the cavity zone is difficult to estimate.To overcome the measurement difficulty,this study adopts the indirect measurement approach in the experimental research of entrainment phenomenon in the cavity.In accordance with the measurement principle,a TVC model fueled by methane is designed.Under two experimental conditions,i.e.with and without direct air intake in the cavity,the influence of the mainstream air flow velocity,the air intake velocity in the cavity,the height of inlet channel,the structure of holder and the structural proportion of the cavity on entrainment in the cavity is studied,respectively,through experiment at atmospheric temperature and pressure.The results suggest that the air flow velocity of mainstream,the air intake velocity of the cavity and the structure of the holder exert significant influence on the air entrainment,while the influence of structural proportion of the cavity is comparatively insignificant.The square root of momentum ratio of cavity air to mainstream air could be used to analyze the correlation of the entrainment data.

  5. CFD Approaches for Modelling Bubble Entrainment by an Impinging Jet

    Directory of Open Access Journals (Sweden)

    Martin Schmidtke

    2009-01-01

    Full Text Available This contribution presents different approaches for the modeling of gas entrainment under water by a plunging jet. Since the generation of bubbles happens on a scale which is smaller than the bubbles, this process cannot be resolved in meso-scale simulations, which include the full length of the jet and its environment. This is why the gas entrainment has to be modeled in meso-scale simulations. In the frame of a Euler-Euler simulation, the local morphology of the phases has to be considered in the drag model. For example, the gas is a continuous phase above the water level but bubbly below the water level. Various drag models are tested and their influence on the gas void fraction below the water level is discussed. The algebraic interface area density (AIAD model applies a drag coefficient for bubbles and a different drag coefficient for the free surface. If the AIAD model is used for the simulation of impinging jets, the gas entrainment depends on the free parameters included in this model. The calculated gas entrainment can be adapted via these parameters. Therefore, an advanced AIAD approach could be used in future for the implementation of models (e.g., correlations for the gas entrainment.

  6. Primacía de la voluntad y virtud moral en Juan Duns Escoto

    Directory of Open Access Journals (Sweden)

    Emiliano Javier Cuccia

    2013-11-01

    Full Text Available The following article studies John Duns Scotus’ doctrine on the subject of moral virtues, and poses the strong influence that has had on it the assumption made by the Doctor Subtilis of the voluntarist theses present at the time. Keywords: voluntarism, moral virtue, John Duns Scotus, moral philosophy, XIVth century.

  7. ParB spreading requires DNA bridging

    NARCIS (Netherlands)

    Graham, Thomas G. W.; Wang, Xindan; Song, Dan; Etson, Candice M.; van Oijen, Antoine M.; Rudner, David Z.; Loparo, Joseph J.

    2014-01-01

    The parABS system is a widely employed mechanism for plasmid partitioning and chromosome segregation in bacteria. ParB binds to parS sites on plasmids and chromosomes and associates with broad regions of adjacent DNA, a phenomenon known as spreading. Although essential for ParB function, the mechani

  8. Critical conditions of bed sediment entrainment due to debris flow

    Directory of Open Access Journals (Sweden)

    M. Papa

    2004-01-01

    Full Text Available The present study describes entrainment characteristics of bed material into debris flow, based on flume tests, numerical and dimensional analyses. Flume tests are conducted to investigate influences of bed sediment size on erosion rate by supplying debris flows having unsaturated sediment concentration over erodible beds. Experimental results show that the erosion rate decreases monotonically with increase of sediment size, although erosion rate changes with sediment concentration of debris flow body. In order to evaluate critical condition of bed sediment entrainment, a length scale which measures an effective bed shear stress is introduced. The effective bed shear stress is defined as total shear stress minus yield stress on the bed surface. The results show that critical entrainment conditions can be evaluated well in terms of Shields curve using the effective bed shear stress instead of a usual bed shear stress.

  9. Cloud microphysical effects of turbulent mixing and entrainment

    CERN Document Server

    Kumar, Bipin; Shaw, Raymond A

    2013-01-01

    Turbulent mixing and entrainment at the boundary of a cloud is studied by means of direct numerical simulations that couple the Eulerian description of the turbulent velocity and water vapor fields with a Lagrangian ensemble of cloud water droplets that can grow and shrink by condensation and evaporation, respectively.The focus is on detailed analysis of the relaxation process of the droplet ensemble during the entrainment of subsaturated air, in particular the dependence on turbulence time scales, droplet number density, initial droplet radius and particle inertia. We find that the droplet evolution during the entrainment process is captured best by a phase relaxation time that is based on the droplet number density with respect to the entire simulation domain and the initial droplet radius. Even under conditions favoring homogeneous mixing, the probability density function of supersaturation at droplet locations exhibits initially strong negative skewness, consistent with droplets near the cloud boundary be...

  10. Turbulence and entrainment length scales in large wind farms

    Science.gov (United States)

    Andersen, Søren J.; Sørensen, Jens N.; Mikkelsen, Robert F.

    2017-03-01

    A number of large wind farms are modelled using large eddy simulations to elucidate the entrainment process. A reference simulation without turbines and three farm simulations with different degrees of imposed atmospheric turbulence are presented. The entrainment process is assessed using proper orthogonal decomposition, which is employed to detect the largest and most energetic coherent turbulent structures. The dominant length scales responsible for the entrainment process are shown to grow further into the wind farm, but to be limited in extent by the streamwise turbine spacing, which could be taken into account when developing farm layouts. The self-organized motion or large coherent structures also yield high correlations between the power productions of consecutive turbines, which can be exploited through dynamic farm control. This article is part of the themed issue 'Wind energy in complex terrains'.

  11. Laminar Plunging Jets - Interfacial Rupture and Inception of Entrainment

    Science.gov (United States)

    Kishore, Aravind

    Interfacial rupture and entrainment are commonly observed, e.g., air bubbles within a container being filled with water from a faucet. The example involves a liquid jet (density, rho, and viscosity, η) plunging into a receiving pool of liquid. Below a critical liquid-jet velocity, the interface develops a cusp-like shape within the receiving pool. The cusp becomes sharper with increasing liquid-jet velocity, and at a critical velocity ( Vc), the interface between the liquid and the surrounding fluid (density, rho0, and viscosity, η0) ruptures. Interfacial tension (sigma) can no longer preserve the integrity of the interface between the two immiscible fluids, and the plunging jet drags/entrains surrounding fluid into the receiving pool. Subsequently, the entrained fluid breaks up into bubbles within the receiving pool. The focus of this dissertation is the numerical prediction of the critical entrainment inception velocities for laminar plunging jets using the Volume-Of-Fluid (VOF) method, a Computational Fluid Dynamics (CFD) method to simulate multi-fluid flows. Canonical to bottle-filling operations in the industry is the plunging-jet configuration -- the liquid jet issues from a nozzle and plunges into a container filled with liquid. Simulations of this configuration require capturing flow phenomena over a large range of length scales (4 orders of magnitude). Results show severe under-prediction of critical entrainment velocities when the maximum resolution is insufficient to capture the sharpening, and eventual rupture, of the interfacial cusp. Higher resolutions resulted in computational meshes with prohibitively large number of cells, and a drastic reduction in time-step values. Experimental results in the literature suggest at least a 100-fold increase in the smallest length scale when the entrained fluid is a liquid instead of air. This narrows the range of length scales in the problem. We exploit the experimental correlation between critical capillary

  12. Optimal Asymptotic Entrainment of Phase-Reduced Oscillators

    CERN Document Server

    Zlotnik, Anatoly

    2011-01-01

    We derive optimal periodic controls for entrainment of a self-driven oscillator to a desired frequency. The alternative objectives of minimizing power and maximizing frequency range of entrainment are considered. A state space representation of the oscillator is reduced to a linearized phase model, and the optimal periodic control is computed from the phase response curve using formal averaging and the calculus of variations. Computational methods are used to calculate the periodic orbit and the phase response curve, and a numerical method for approximating the optimal controls is introduced. Our method is applied to asymptotically control the period of spiking neural oscillators modeled using the Hodgkin-Huxley equations. This example illustrates the optimality of entrainment controls derived using phase models when applied to the original state space system

  13. On robustness of phase resetting to cell division under entrainment.

    Science.gov (United States)

    Ahmed, Hafiz; Ushirobira, Rosane; Efimov, Denis

    2015-12-21

    The problem of phase synchronization for a population of genetic oscillators (circadian clocks, synthetic oscillators, etc.) is considered in this paper, taking into account a cell division process and a common entrainment input in the population. The proposed analysis approach is based on the Phase Response Curve (PRC) model of an oscillator (the first order reduced model obtained for the linearized system and inputs with infinitesimal amplitude). The occurrence of cell division introduces state resetting in the model, placing it in the class of hybrid systems. It is shown that without common entraining input in all oscillators, the cell division acts as a disturbance causing phase drift, while the presence of entrainment guarantees boundedness of synchronization phase errors in the population. The performance of the obtained solutions is demonstrated via computer experiments for two different models of circadian/genetic oscillators (Neurospora׳s circadian oscillation model and the repressilator).

  14. Turbulence and entrainment length scales in large wind farms.

    Science.gov (United States)

    Andersen, Søren J; Sørensen, Jens N; Mikkelsen, Robert F

    2017-04-13

    A number of large wind farms are modelled using large eddy simulations to elucidate the entrainment process. A reference simulation without turbines and three farm simulations with different degrees of imposed atmospheric turbulence are presented. The entrainment process is assessed using proper orthogonal decomposition, which is employed to detect the largest and most energetic coherent turbulent structures. The dominant length scales responsible for the entrainment process are shown to grow further into the wind farm, but to be limited in extent by the streamwise turbine spacing, which could be taken into account when developing farm layouts. The self-organized motion or large coherent structures also yield high correlations between the power productions of consecutive turbines, which can be exploited through dynamic farm control.This article is part of the themed issue 'Wind energy in complex terrains'.

  15. Élaboration de couches minces de carbone par ablation laser femtoseconde pour application aux biomatériaux implantables

    Science.gov (United States)

    Loir, A.-S.; Garrelie, F.; Donnet, C.; Subtil, J.-L.; Belin, M.; Forest, B.; Rogemond, F.; Laporte, P.

    2005-06-01

    Des films de tetrahedral amorphous-Carbon (ta-C) ont été déposés, sous vide poussé, par ablation d'une cible de graphite avec un laser Ti : saphir (durée d'impulsion 170 fs, fréquence de répétition 1 kHz, énergie maximale par impulsion 1,5 mJ, longueur d'onde 800 nm) sur substrats standard et sur biomatériaux (acier AISI 316L, polyéthylène à très haut poids moléculaire). Les propriétés de ces couches (structure, propriétés nanomécaniques et tribologiques) ont été caractérisées, en fonction des conditions d'élaboration, en examinant l'intérêt de l'utilisation d'un laser femtoseconde et leur capacité à satisfaire aux exigences spécifiques du domaine biomédical. Les propriétés d'adhérence des films ont été considérablement améliorées lors du dépôt sur des substrats en acier inoxydable préalablement préparés par décapage ionique in situ sous atmosphère d'argon. La surface hémisphérique d'une tête fémorale, en acier inoxydable, de prothèse de hanche de diamètre 22,2 mm a été revêtue d'un film de DLC adhérent et homogène en épaisseur. La résistance à l'usure de ce revêtement sera quantifiée à l'aide d'un simulateur de marche durant un million de cycles (correspondant à une année d'activité physique d'un être humain).

  16. Dryout-type critical heat flux in vertical upward annular flow: effects of entrainment rate, initial entrained fraction and diameter

    Science.gov (United States)

    Wu, Zan; Wadekar, Vishwas; Wang, Chenglong; Sunden, Bengt

    2017-07-01

    This study aims to reveal the effects of liquid entrainment, initial entrained fraction and tube diameter on liquid film dryout in vertical upward annular flow for flow boiling. Entrainment and deposition rates of droplets were included in mass conservation equations to estimate the local liquid film mass flux in annular flow, and the critical vapor quality at dryout conditions. Different entrainment rate correlations were evaluated using flow boiling data of water and organic liquids including n-pentane, iso-octane and R134a. Effect of the initial entrained fraction (IEF) at the churn-to-annular flow transition was also investigated. A transitional Boiling number was proposed to separate the IEF-sensitive region at high Boiling numbers and the IEF-insensitive region at low Boiling numbers. Besides, the diameter effect on dryout vapor quality was studied. The dryout vapor quality increases with decreasing tube diameter. It needs to be pointed out that the dryout characteristics of submillimeter channels might be different because of different mechanisms of dryout, i.e., drying of liquid film underneath long vapor slugs and flow boiling instabilities.

  17. Génération du comportement observable d'un système pour l'étude de la diagnosticabilité de défauts

    OpenAIRE

    Batteux, Michel,; Fiani, Philippe; Rapin, Nicolas; Dague, Philippe

    2011-01-01

    National audience; Cet article décrit une approche d'étude de la diagnosticabilité des défauts d'un système automatique par caractérisation de son comportement observable. Les systèmes automatiques sont des systèmes complexes comprenant une multitude de composants interagissant les uns avec les autres. Des défauts peuvent y apparaitre avec un impact néfaste sur leur environnement ou leur propre intégrité. Il est donc important de compléter ces systèmes de dispositifs de diagnostic permettant ...

  18. Modeling and simulation of an entrained flow coal gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Govind, R.; Shah, J.

    1984-01-01

    A mathematical model has been developed to stimulate the Texaco downflow entrained-bed pilot-plant gasifier using coal liquefaction residues and coal-water slurries as feedstocks. This model describes the physical and chemical processes occurring in an entrained coal gasifier. The gasification kinetics describes different complex reactions occurring in the gasifier and the hydrodynamics describes mass, momentum and energy balances for solid and gas phases. Temperature, concentration and velocity profiles along the reactor height were obtained by solving the mass, momentum and energy balances. Parameter studies were made to provide a better understanding of the reactor performance for various inlet feed conditions utilizing the model.

  19. Evidence for Little Shallow Entrainment in Starting Mantle Plumes

    Science.gov (United States)

    Lohmann, F. C.; Phipps Morgan, J.; Hort, M.

    2005-12-01

    Basalts from intraplate or hotspot ocean islands show distinct geochemical signatures. Their diversity in composition is generally believed to result from the upwelling plume entraining shallow mantle material during ascent, while potentially also entraining other deep regions of the mantle. Here we present results from analogue laboratory experiments and numerical modelling that there is evidence for little shallow entrainment into ascending mantle plumes, i.e. most of the plume signature is inherited from the source. We conducted laboratory experiments using glucose syrup contaminated with glass beads to visualize fluid flow and origin. The plume is initiated by heating from below or by injecting hot, uncontaminated syrup. Particle movement is captured by a CCD camera. In our numerical experiments we solve the Stokes equations for a viscous fluid at infinite Prandtl number with passive tracer particles being used to track fluid flow and entrainment rates, simulating laboratory as well as mantle conditions. In both analogue experiments and numerical models we observe the classical plume structure being embedded in a `sheath' of material from the plume source region that retains little of the original temperature anomaly of the plume source. Yet, this sheath ascends in the `slipstream' of the plume at speeds close to the ascent speed of the plume head, and effectively prevents the entrainment of surrounding material into the plume head or plume tail. We find that the source region is most effectively sampled by an ascending plume and that compositional variations in the source region are preserved during plume ascent. The plume center and plume sheath combined are composed of up to 85% source material. However, there is also evidence of significant entrainment of up to 30% of surrounding material into the outer layers of the plume sheath. Entrainment rates are found to be influenced by mantle composition and structure, with the radial viscosity profile of the

  20. Entrained flow gasification of coal/bio-oil slurries

    DEFF Research Database (Denmark)

    Feng, Ping; Lin, Weigang; Jensen, Peter Arendt;

    2016-01-01

    Coal/bio-oil slurry (CBS) is a new partial green fuel for bio-oil utilization. CBS reacts with gasification agents at high temperatures and converts into hydrogen and carbon monoxide. This paper provides a feasibility study for the gasification of CBS in an atmospheric entrained flow reactor...... for syngas production. Experiments have shown that CBS can be successfully processed and gasified in the entrained flow reactor to produce syngas with almost no tar content and low residual carbon formation. High reactor temperature and steam/carbon ratio is favourable for H2 production. At 1400 °C...

  1. The great dun fell cloud experiment 1993: An overview

    Science.gov (United States)

    Choularton, T. W.; Colvile, R. N.; Bower, K. N.; Gallagher, M. W.; Wells, M.; Beswick, K. M.; Arends, B. G.; Möls, J. J.; Kos, G. P. A.; Fuzzi, S.; Lind, J. A.; Orsi, G.; Facchini, M. C.; Laj, P.; Gieray, R.; Wieser, P.; Engelhardt, T.; Berner, A.; Kruisz, C.; Möller, D.; Acker, K.; Wieprecht, W.; Lüttke, J.; Levsen, K.; Bizjak, M.; Hansson, H.-C.; Cederfelt, S.-I.; Frank, G.; Mentes, B.; Martinsson, B.; Orsini, D.; Svenningsson, B.; Swietlicki, E.; Wiedensohler, A.; Noone, K. J.; Pahl, S.; Winkler, P.; Seyffer, E.; Helas, G.; Jaeschke, W.; Georgii, H. W.; Wobrock, W.; Preiss, M.; Maser, R.; Schell, D.; Dollard, G.; Jones, B.; Davies, T.; Sedlak, D. L.; David, M. M.; Wendisch, M.; Cape, J. N.; Hargreaves, K. J.; Sutton, M. A.; Storeton-West, R. L.; Fowler, D.; Hallberg, A.; Harrison, R. M.; Peak, J. D.

    The 1993 Ground-based Cloud Experiment on Great Dun Fell used a wide range of measurements of trace gases, aerosol particles and cloud droplets at five sites to study their sources and sinks especially those in cloud. These measurements have been interpreted using a variety of models. The conclusions add to our knowledge of air pollution, acidification of the atmosphere and the ground, eutrophication and climate change. The experiment is designed to use the hill cap cloud as a flow-through reactor, and was conducted in varying levels of pollution typical of much of the rural temperate continental northern hemisphere in spring-time.

  2. Implantació d'un CRM a Colabora Birmania

    OpenAIRE

    2016-01-01

    Aquest treball planteja tot el projecte d'implantació d'un sistema d'informació CRM en una ONG per a la gestió dels seus clients (col·laboradors i associats) des d'una primera fase inicial de definició de la situació actual, identificació de necessitats, analitzant les diferents opcions de mercat possibles, i seleccionant per a la seva implantació la que millor s'ajusti a les necessitats de l'organització concreta. Este trabajo plantea todo el proyecto de implantación de un sistema de info...

  3. Amelioration de l'efficacite energetique du procede d'electrolyse de l'aluminium conception d'un nouveau bloc cathodique

    Science.gov (United States)

    Blais, Mathieu

    Au Quebec, les alumineries sont de grandes consommatrices d'energie electrique, soit pres de 14 % de la puissance installee d'Hydro-Quebec. Dans ce contexte, des petits gains en efficacite energetique des cuves d'electrolyse pourraient avoir un impact important sur la reduction globale de la consommation d'electricite. Le projet de maitrise decrit dans cette etude repond a la problematique suivante : comment l'optimisation de la geometrie d'un bloc cathodique en vue d'uniformiser la densite de courant peut augmenter l'efficacite energetique et la duree de vie de la cuve d'aluminium? Le but premier du projet est de modifier la geometrie en vue d'ameliorer le comportement thermoelectrique des blocs cathodiques et d'accroitre par le fait meme l'efficacite energetique du procede de production d'aluminium. La mauvaise distribution de la densite de courant dans la cuve est responsable de certains problemes energetiques ayant des impacts negatifs sur l'economie et l'environnement. Cette non-uniformite de la distribution du courant induit une usure prematuree de la surface de la cathode et contribue a reduire la stabilite magnetohydrodynamique de la nappe de metal liquide. Afin de quantifier les impacts que peut avoir l'uniformisation de la densite de courant a travers le bloc cathodique, un modele d'un bloc cathodique d'une cuve de la technologie AP-30 a ete concu et analyse par elements finis. A partir de son comportement thermoelectrique et de donnees experimentales d'une cuve AP-30 tirees de la litterature, une correlation entre le profil de densite de courant a la surface du bloc et le taux d'erosion local au meme endroit a ete creee. Cette relation correspond au modele predictif de la duree de vie de tout bloc du meme materiau a partir de son profil de densite de courant. Ensuite, une programmation a ete faite incorporant dans une meme fonction cout les impacts economiques de la duree de vie, de la chute de voltage cathodique et de l'utilisation de nouveaux materiaux

  4. Corrélations entre maillages 3D au moyen du logiciel R : application à l'imagerie par IRM de l'accident vasculaire cérébral

    OpenAIRE

    2013-01-01

    International audience; Nous présentons une analyse statistique, réalisée avec le logiciel R, sur des images obtenues par imagerie par résonance magnétique (IRM) dans le cadre d'un suivi longitudinal de patients ayant subi un accident vasculaire cérébral (AVC). L'analyse s'effectue sur une cohorte d'environ 400 patients suivis à 4 dates différentes : heure d'arrivée aux urgences, deux heures après, deux jours après puis un mois après. Les patients de cette cohorte sont tous atteints d'un AVC,...

  5. Characterization of Residual Particulates from Biomass Entrained Flow Gasification

    DEFF Research Database (Denmark)

    Qin, Ke; Lin, Weigang; Fæster, Søren

    2013-01-01

    Biomass gasification experiments were carried out in a bench scale entrained flow reactor, and the produced solid particles were collected by a cyclone and a metal filter for subsequent characterization. During wood gasification, the major part of the solid material collected in the filter is soot...

  6. Entrainment at a sediment concentration interface in turbulent channel flow

    Science.gov (United States)

    Salinas, Jorge; Shringarpure, Mrugesh; Cantero, Mariano; Balachandar, S.

    2016-11-01

    In this work we address the role of turbulence on entrainment at a sediment concentration interface. This process can be conceived as the entrainment of sediment-free fluid into the bottom sediment-laden flow, or alternatively, as the entrainment of sediment into the top sediment-free flow. We have performed direct numerical simulations for fixed Reynolds and Schmidt numbers while varying the values of Richardson number and particle settling velocity. The analysis performed shows that the ability of the flow to pick up a given sediment size decreases with the distance from the bottom, and thus only fine enough sediment particles are entrained across the sediment concentration interface. For these cases, the concentration profiles evolve to a final steady state in good agreement with the well-known Rouse profile. The approach towards the Rouse profile happens through a transient self-similar state. Detailed analysis of the three dimensional structure of the sediment concentration interface shows the mechanisms by which sediment particles are lifted up by tongues of sediment-laden fluid with positive correlation between vertical velocity and sediment concentration. Finally, the mixing ability of the flow is addressed by monitoring the center of mass of the sediment-laden layer. With the support of ExxonMobil, NSF, ANPCyT, CONICET.

  7. Efficiency of brainwave entrainment by binaural beats in reducing anxiety

    Directory of Open Access Journals (Sweden)

    Ahmad Alipoor

    2014-04-01

    Full Text Available Background: Anxiety is a fundamental phenomenon that is a common symptom in all mental disorders. The aim of the present study was to assess the effect of brainwave entrainment on anxiety reduction using binaural beats. Methods: In this experimental double-blind study, 30 employees were selected from an engineering research firm through random sampling and replacement and divided into two groups: control group and experimental group. All participants completed the Spielberger’s State-Trait Anxiety Inventory (STAI. Then, the experimental group listened to binaural beats which was recorded on a non-vocal piece of music for 4 weeks, 3 sessions each week. Each session lasted about 20 minutes. At the same time, the control group listened to the background music without any entrainment sound. At the end, both groups completed the anxiety questionnaire and the anxiety scores of both groups obtained before and after intervention were analyzed by ANCOVA. Results: The findings showed that the brainwave entrainment using binaural beats led to the significant reduction of state anxiety (P<0.001 and trait anxiety (P<0.018. Conclusion: Brainwave entrainment using binaural beats is an effective factor in decreasing state and trait anxiety; so, it can be used to reduce anxiety in mental health centers.

  8. Entrainment and maximum vapour flow rate of trays

    NARCIS (Netherlands)

    Van Sinderen, AH; Wijn, EF; Zanting, RWJ

    This is a report on free entrainment measurements in a small (0.20 m x 0.20 in) air-water column. An adjustable weir controlled the liquid height on a test tray. Several sieve and valve trays were studied. The results were interpreted with a two- or three-layer model of the two-phase mixture on the

  9. Mechanism of air entrainment by a disturbed liquid jet

    NARCIS (Netherlands)

    Ohl, C.D.; Oguz, H.N.; Prosperetti, A.

    2000-01-01

    It was shown in recent work that the crests of surface disturbances on a falling jet are a powerful agent for air entrainment at the free surface of a liquid pool. The paper explores the opposite case in which the jet is disturbed so as to form an axisymmetric trough, rather than a crest. It is foun

  10. ENTRAINED-FLOW ADSORPTION OF MERCURY USING ACTIVATED CARBON

    Science.gov (United States)

    Bench-scale experiments were conducted in a flow reactor to simulate entrained-flow capture of elemental mercury (Hg) by activated carbon. Adsorption of Hg by several commercial activated carbons was examined at different carbon-to-mercury (C:Hg) ratios (by weight) (600:1 - 29000...

  11. Entrainment to an auditory signal: Is attention involved?

    NARCIS (Netherlands)

    Kunert, R.; Jongman, S.R.

    2017-01-01

    Many natural auditory signals, including music and language, change periodically. The effect of such auditory rhythms on the brain is unclear however. One widely held view, dynamic attending theory, proposes that the attentional system entrains to the rhythm and increases attention at moments of

  12. Entrainment to an auditory signal: Is attention involved?

    NARCIS (Netherlands)

    Kunert, R.; Jongman, S.R.

    2017-01-01

    Many natural auditory signals, including music and language, change periodically. The effect of such auditory rhythms on the brain is unclear however. One widely held view, dynamic attending theory, proposes that the attentional system entrains to the rhythm and increases attention at moments of rhy

  13. High-temperature entrained flow gasification of biomass

    DEFF Research Database (Denmark)

    Qin, Ke; Lin, Weigang; Jensen, Peter Arendt

    2012-01-01

    Biomass (wood and straw) gasification has been studied in a laboratory scale atmospheric pressure entrained flow reactor. Effects of reaction temperature, steam/carbon molar ratio, excess air ratio, and biomass type on the solid, liquid and gas products were investigated. The biomass was completely...

  14. Investigation of the Entrainment Phenomenon Using a Scaling Approach

    Science.gov (United States)

    Kishore, Aravind; Ghia, Urmila

    2014-11-01

    Air entrainment is a commonly observed phenomenon; we see it when filling a glass with water from a faucet, in the frothing of the ocean surface, in white water rapids, etc. The focus of our work is the numerical simulation of the entrainment phenomenon associated with laminar plunging jets. With increasing jet velocity, the interfacial cusp formed between the jet and the liquid pool becomes sharper. At a critical jet velocity, entrainment inception occurs, i.e., the interfacial cusp breaks, the interface ruptures, and air is pulled into the liquid pool. We conduct two-fluid simulations using the Volume-Of-Fluid (VOF) methodology. The large range of length scales in the flow presents a major computational challenge. We postulate an approach based on scaling of the underlying physics and this helps alleviate the constraints that the physics poses on the numerical method. The approach is validated using a simple flow configuration - a cylinder rotating at an interface between two fluids. Our simulations capture the sharpening of the interfacial cusp, and the sudden rupture of the interface. The predicted critical entrainment velocities are within 1% of experimental data, thereby providing confidence in the approach. This work was supported by the UC Simulation Center at the University of Cincinnati.

  15. Queueing-Based Synchronization and Entrainment for Synthetic Gene Oscillators

    Science.gov (United States)

    Mather, William; Butzin, Nicholas; Hochendoner, Philip; Ogle, Curtis

    Synthetic gene oscillators have been a major focus of synthetic biology research since the beginning of the field 15 years ago. They have proven to be useful both for biotechnological applications as well as a testing ground to significantly develop our understanding of the design principles behind synthetic and native gene oscillators. In particular, the principles governing synchronization and entrainment of biological oscillators have been explored using a synthetic biology approach. Our work combines experimental and theoretical approaches to specifically investigate how a bottleneck for protein degradation, which is present in most if not all existing synthetic oscillators, can be leveraged to robustly synchronize and entrain biological oscillators. We use both the terminology and mathematical tools of queueing theory to intuitively explain the role of this bottleneck in both synchronization and entrainment, which extends prior work demonstrating the usefulness of queueing theory in synthetic and native gene circuits. We conclude with an investigation of how synchronization and entrainment may be sensitive to the presence of multiple proteolytic pathways in a cell that couple weakly through crosstalk. This work was supported by NSF Grant #1330180.

  16. Universal mechanism for air entrainment during liquid impact

    NARCIS (Netherlands)

    Hendrix, Maurice H.W.; Bouwhuis, Wilco; Meer, van der Devaraj; Lohse, Detlef; Snoeijer, Jacco H.

    2016-01-01

    When a millimetre-sized liquid drop approaches a deep liquid pool, both the interface of the drop and the pool deform before the drop touches the pool. The build-up of air pressure prior to coalescence is responsible for this deformation. Due to this deformation, air can be entrained at the bottom o

  17. Entrainment process of carbon dioxide in the atmospheric boundary layer

    NARCIS (Netherlands)

    Vilà-Guerau de Arellano, J.; Gioli, B.; Miglietta, F.; Jonker, H.J.J.; Klein Baltink, H.; Hutjes, R.W.A.; Holtslag, A.A.M.

    2004-01-01

    Aircraft and surface measurements of turbulent thermodynamic variables and carbon dioxide (CO2) were taken above a grassland in a convective atmospheric boundary layer. The observations were analyzed to assess the importance of the entrainment process for the distribution and evolution of carbon dio

  18. Experimental study on entrainment of large wood in lowland rivers

    NARCIS (Netherlands)

    Crosato, A.; Rajbhandari, N.; Comiti, F.; Uijttewaal, W.S.J.

    2011-01-01

    Wood transport in rivers, typically occurring during flood events, represents a relevant hazard for its potential to create obstruction at bridges and narrow cross-sections. Therefore, the understanding and prediction of entrainment and transport dynamics of woody material of different shapes, densi

  19. Measured gas and particle temperatures in VTT's entrained flow reactor

    DEFF Research Database (Denmark)

    Clausen, Sønnik; Sørensen, L.H.

    2006-01-01

    Particle and gas temperature measurements were carried out in experiments on VTTs entrained flow reactor with 5% and 10% oxygen using Fourier transform infrared emission spectroscopy (FTIR). Particle temperature measurements were performed on polish coal,bark, wood, straw particles, and bark...

  20. Entrainment of Goodwin’s oscillators by periodic exogenous signals

    NARCIS (Netherlands)

    Proskurnikov, Anton; Cao, Ming; Zhang, Hai-Tao

    2015-01-01

    The circadian pacemakers, which have been discovered in most of living organisms, are known to be entrainable by the environmental exogenuous cues, or zeitgebers (“time givers”). If the influence of an exogenous periodic excitation is sufficiently long, the internal circadian “clock” adjusts the

  1. Traitements didactiques preventifs d'un type de conceptions erronees en sciences physiques chez des eleves du secondaire

    Science.gov (United States)

    Blondin, Andre

    Dans un contexte constructiviste, les connaissances anterieures d'un individu sont essentielles a la construction de nouvelles connaissances. Quelle qu'en soit la source (certaines de ces connaissances ont ete elaborees en classe, d'autres ont ete elaborees par interaction personnelle de l'individu avec son environnement physique et social), ces connaissances, une fois acquises, constituent les matieres premieres de l'elaboration des nouvelles conceptions de cet individu. Generalement, cette influence est consideree comme positive. Cependant, dans un milieu scolaire ou l'apprentissage de certaines conceptions enchassees dans un programme d'etudes et enterinees par l'ensemble d'une communaute est obligatoire, certaines connaissances anterieures peuvent entraver la construction des conceptions exigees par la communaute. La litterature abonde de tels exemples. Cependant, certaines connaissances anterieures, en soi tout a fait conformes a l'Heritage, peuvent aussi, parce qu'utilisees de facon non pertinente, entraver la construction d'une conception exigee par la communaute. Ici, la litterature nous donne peu d'exemples de ce type, mais nous en fournirons quelques-uns dans le cadre theorique, et ce sera un d'entre eux qui servira de base a nos propos. En effet, une grande proportion d'eleves inscrits a un cours de sciences physiques de la quatrieme secondaire, en reponse a un probleme deja solutionne durant l'annee et redonne lors d'un examen sommatif, "Pourquoi la Lune nous montre-t-elle toujours la meme face?", attribue principalement la cause de ce phenomene a la rotation de la Terre sur son axe. En tant que responsable de l'enseignement de ce programme d'etudes, plusieurs questions nous sont venues a l'esprit, entre autres, comment, dans un contexte constructiviste, est-il possible de reduire chez un eleve, l'impact de cette connaissance anterieure dans l'elaboration de la solution et ainsi prevenir la construction d'une conception erronee? Nous avons teste nos

  2. Elusloom lennukiga puhkusele / Inge Parring

    Index Scriptorium Estoniae

    Parring, Inge

    2003-01-01

    Ilmunud ka: Delovõje Vedomosti 1. okt. lk. 13. Air Cargo Estonia/ACE Logisticsi müügijuht Inge Parring tutvustab elusloomade transpordivõimalusi. Vt. samas: Loomade transportimiseks vajalikud dokumendid

  3. Le carcinome neuro-endocrine cutané primitif: à propos d'un nouveau cas et revue de la littérature

    Science.gov (United States)

    Boukind, Samira; Elatiqi, Oumkeltoum; Dlimi, Meriem; Elamrani, Driss; Benchamkha, Yassine; Ettalbi, Saloua

    2015-01-01

    Le carcinome neuro- endocrine cutané primitif (CNEC) est une tumeur cutanée rare et agressive du sujet âgé, favorisée par le soleil et l'immunodépression. Elle est caractérisée par une évolution agressive avec un fort taux de récidive, une évolution ganglionnaire régionale et un risque de métastases à distance. Nous rapportons un cas de cette tumeur chez un patient âgé de 67 ans sous forme d'un placard nodulaire hémorragique mesurant 16 /14 cm. Le patient a bénéficié d'une exérèse chirurgicale large avec couverture de la perte de substance par un lambeau musculo-cutané du muscle grand dorsal, un curage ganglionnaire axillaire et une radiothérapie adjuvante. Après un recul de 2 ans et 2 mois, le patient est toujours vivant sans métastase ni récidive. La littérature étant pauvre, la prise en charge diagnostique et thérapeutique est controversée et donc hétérogène. Globalement le pronostic est mauvais, et certains paramètres corrélés au pronostic sont précisés. PMID:26185585

  4. Entrainment of spontaneous cerebral hemodynamic oscillations to behavioral responses.

    Science.gov (United States)

    Pfurtscheller, Gert; Walther, Mario; Bauernfeind, Günther; Barry, Robert J; Witte, Herbert; Müller-Putz, Gernot R

    2014-04-30

    Entrainment in physiological systems can be manifest in cases where phase-coupling (synchronization) between slow intrinsic oscillations and periodic motor responses, or vice versa, takes place. To test whether voluntary movement has something in common with entrainment of slow hemodynamic oscillations to motor responses, we studied blood pressure (BP), heart rate beat-to-beat intervals (RRI) and prefrontal (de)oxyhemoglobin (Hb/HbO2) during 5min of rest, 10min of self-paced, voluntary movements and 10min of stimulus-paced movements at 10s intervals in 9 subjects. Subjects were divided into 2 groups according to the timing of voluntary finger movements. It appeared that these movements occurred at relatively regular intervals of approximately 10s in 5 subjects (group A); while 4 subjects showed random or very short inter-movement intervals (group B). Two remarkable results were obtained: first, the phase coupling (COH(2)) between BP and RRI showed a significant (p=0.0061) interaction between activity (rest vs. movement) and group (A vs. B), with an increased (p=0.0003) coupling in group A. Second, the COH(2) between BP and Hb oscillations showed a significant (p=0.034) interaction between activity and group, with a decreased (p=0.079) coupling in group B. These results suggest that subjects able to initiate self-paced, voluntary movements at relatively regular intervals of ∼10s show an entrainment potential between physiological oscillations and motor responses. This also provides the first evidence that not only physiological oscillations can be entrained to motor responses, but also motor responses (voluntary movements) can be entrained to slow intrinsic oscillations.

  5. Rhythmic light stimulation modifies brain oscillations via entrainment

    Directory of Open Access Journals (Sweden)

    Annika eNotbohm

    2016-02-01

    Full Text Available The functional relevance of brain oscillations in the alpha frequency range (8-13Hz has been repeatedly investigated through the use of rhythmic visual stimulation. The underlying mechanism of the steady-state visual evoked potential (SSVEP measured in EEG during rhythmic stimulation, however, is not known. There are two hypotheses on the origin of the SSVEPs: entrainment of brain oscillations and superposition of event-related responses (ERPs. The entrainment but not the superposition hypothesis justifies rhythmic visual stimulation as a means to manipulate brain oscillations, because superposition assumes a linear summation of single responses, independent from ongoing brain oscillations. Here, we stimulated participants with a rhythmic flickering light of different frequencies and intensities.. We measured entrainment by comparing the phase coupling of brain oscillations stimulated by rhythmic visual flicker with the oscillations induced by arrhythmic jittered stimulation, varying the time, stimulation frequency, and intensity conditions. In line with a theoretical concept of entrainment (the so called Arnold tongue, we found the phase coupling to be more pronounced with increasing stimulation intensity as well as at stimulation frequencies closer to each participant’s intrinsic frequency. Only inside the Arnold tongue did the conditions significantly differ from the jittered stimulation. Furthermore, even in a single sequence of an SSVEP, we found non-linear features (intermittency of phase locking that contradict the linear summation of single responses, as assumed by the superposition hypothesis. Our findings provide unequivocal evidence that visual rhythmic stimulation entrains brain oscillations, thus validating the approach of rhythmic stimulation as a manipulation of brain oscillations.

  6. Pars planitis in a family.

    Science.gov (United States)

    Tejada, P; Sanz, A; Criado, D

    1994-01-01

    The familial occurrence of pars planitis is rare. We have found ten cases reported previously. We describe a new case of pars planitis in a family. The affected members included a mother and two of her four children. The family was tested for HLA antigens in order to establish a comparison with others HLA types by different authors. We have not identified any cause for the familial occurrence of this disease. We discuss the role of genetic and ambiental factors.

  7. La dermatomyosite paranéoplasique révélant un carcinome indifférencié du nasopharynx: à propos d'un cas

    Science.gov (United States)

    Ziani, Fatima Zahra; Brahmi, Sami Aziz; Najib, Rajae; Kanab, Rajae; Arifi, Samia; Mernissi, Fatima Zahra; Mellas, Nawfal

    2016-01-01

    La dermatomyosite (DM) est une maladie inflammatoire d'origine inconnue qui se manifeste sous forme de myopathie associée à lésions cutanées typiques. L'association DM et cancer est fréquente (18 a 32% selon les séries). Décrite pour la première fois par Stertz en 1916 en association avec un cancer gastrique. Tous les types histologiques et toutes les localisations de cancers observés danss la population générale peuvent être associés à la DM. Son association avec le carcinome nasopharyngé (NPC) est peu décrite et de l'ordre d'un cas pour 1000 cas de cancer nasopharyngé. Nous rapportons une observation de dermatomyosite révélant un cancer du nasopharynx localement avance. PMID:27583093

  8. Bioaccumulation d'un polychlorobiphényle commercial dans une chaîne trophodynamique expérimentale en eau douce

    Directory of Open Access Journals (Sweden)

    CAZIN J. C.

    1978-04-01

    Full Text Available Ce travail décrit les conditions d'expérimentation d'un polychlorobiphényle commercial sur les différents maillons d'une chaîne alimentaire en eau douce : algues-crustacés-poissons. Après avoir déterminé les modalités de contamination compatibles avec la croissance normale des organismes végétaux et animaux, les cinétiques de concentration au niveau de chaque espèce, l'association des différents maillons a permis d'apprécier l'importance du transfert biologique du polluant qui apparaît limité, aux environs de 10 ppm, par l'état d'équilibre qui s'installe progressivement dans le milieu aquatique.

  9. PROPOSITION D'UN MODELE DE L'EFFICACITE DU CO-COMMISSARIAT AUX COMPTES DANS LES SOCIETES ANONYMES COTEES FRANÇAISES

    OpenAIRE

    Jeannette Bennecib

    2002-01-01

    Si le commissariat aux comptes est une institution reconnue par un large public, le co-commissariat aux comptes semble ignoré. Dans un contexte de remise en cause de la crédibilité des informations financières et de l'opinion de l'auditeur, nous nous interrogeons sur l'efficacité d'un double contrôle dans les SA cotées françaises. A partir du cadre conceptuel normatif de l'efficacité du cocommissariat aux comptes, nous proposons un modèle explicatif fondé sur le principe d'indépendance en app...

  10. Automorphismes Hamiltoniens d'un Produit Star et Opérateurs de Dirac Symplectiques / Hamiltonian Automorphisms of a Star Product and Symplectic Dirac Operators

    OpenAIRE

    La Fuente Gravy, Laurent

    2013-01-01

    Cette thèse est consacrée à l'étude de deux sujets de géométrie symplectique inspirésde la physique mathématique. Les thèmes que nous développerons mettent en évidence certaines connexions avec la topologie symplectique d'une part, la géométrie Riemannienne d'autre part.Dans la partie 1, nous étudions la quantification par déformation formelle d'une variété symplectique, à l'aide de produits star. Nous définissons le groupe des automorphimeshamiltoniens d'un produit star formel. En nous inspi...

  11. Biodégradation des hydrocarbures aromatiques polycycliques. Approche microbiologique et application au traitement d'un sol pollué

    OpenAIRE

    Bidaud, Christine

    1998-01-01

    278 pages; No english abstract; Les Hydrocarbures Aromatiques Polycycliques (HAP) sont des molécules qui posent un grave problème environnemental à cause de leurs propriétés toxiques, cancérigènes, voire tératogènes. Les sites d'anciennes usines à gaz sont souvent pollués par ces produits issus de la combustion incomplète de matières organiques. Notre travail a été réalisé à partir d'échantillons de sol issus d'un site d'ancienne usine à gaz. Nous avons d'abord étudié la biodégradabilité natu...

  12. Prokaryotic ParA-ParB-parS system links bacterial chromosome segregation with the cell cycle.

    Science.gov (United States)

    Mierzejewska, Jolanta; Jagura-Burdzy, Grażyna

    2012-01-01

    While the essential role of episomal par loci in plasmid DNA partitioning has long been appreciated, the function of chromosomally encoded par loci is less clear. The chromosomal parA-parB genes are conserved throughout the bacterial kingdom and encode proteins homologous to those of the plasmidic Type I active partitioning systems. The third conserved element, the centromere-like sequence called parS, occurs in several copies in the chromosome. Recent studies show that the ParA-ParB-parS system is a key player of a mitosis-like process ensuring proper intracellular localization of certain chromosomal regions such as oriC domain and their active and directed segregation. Moreover, the chromosomal par systems link chromosome segregation with initiation of DNA replication and the cell cycle.

  13. Are non-human primates capable of rhythmic entrainment? Evidence for the gradual audiomotor evolution hypothesis

    NARCIS (Netherlands)

    Merchant, H.; Honing, H.

    2014-01-01

    We propose a decomposition of the neurocognitive mechanisms that might underlie interval-based timing and rhythmic entrainment. Next to reviewing the concepts central to the definition of rhythmic entrainment, we discuss recent studies that suggest rhythmic entrainment to be specific to humans and a

  14. Estimated Entrainment of Dungeness Crab During Dredging For The Columbia River Channel Improvement Project

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Walter H.; Williams, Greg D.; Skalski, John R.

    2002-12-01

    The studies reported here focus on issues regarding the entrainment of Dungeness crab related to the proposed Columbia River Channel Improvement Project and provided direct measurements of crab entrainment rates at three locations (Desdomona Shoals, Upper Sands, and Miller Sands) from RM4 to RM24 during summer 2002. Entrainment rates for all age classes of crabs ranged from zero at Miller Sands to 0.224 crabs per cy at Desdemona Shoals in June 2002. The overall entrainment rate at Desdomona Shoals in September was 0.120 crabs per cy. A modified Dredge Impact Model (DIM) used the summer 2002 entrainment rates to project crab entrainment and adult equivalent loss and loss to the fishery for the Channel Improvement Project. To improve the projections, entrainment data from Flavel Bar is needed. The literature, analyses of salinity intrusion scenarios, and the summer 2002 site-specific data on entrainment and salinity all indicate that bottom salinity influences crab distribution and entrainment, especially at lower salinities. It is now clear from field measurements of entrainment rates and salinity during a period of low river flow (90-150 Kcfs) and high salinity intrusion that entrainment rates are zero where bottom salinity is less than 16 o/oo most of the time. Further, entrainment rates of 2+ and older crab fall with decreasing salinity in a clear and consistent manner. More elaboration of the crab distribution- salinity model, especially concerning salinity and the movements of 1+ crab, is needed.

  15. Autour d'un mystère de l'histoire du livre. Les trois versions du premier volume du Voyage pittoresque de Choiseul-Gouffier

    Directory of Open Access Journals (Sweden)

    Ioannis Koubourlis

    2009-01-01

    Full Text Available Dans cet article, il est question d'un grand mystère de l'histoire du livre, celui de l'existence de trois versions différentes du premier volume du Voyage pittoresque de la Grèce (1782 de Choiseul-Gouffier, c'est-à-dire d'un ouvrage majeur pour la floraison des idées philhellènes dans l'Europe des XVIIIe-XIXe siècles. On sait, grâce à la correspondance de l'auteur, qu'il avait pris la décision de réviser son texte dès 1783, en raison de sa candidature pour le poste d'Ambassadeur de France à Constantinople. Par contre, on n'en sait pas davantage sur le lieu et le temps exacts où il a travaillé les deux nouvelles versions, portant également la date 1782, ni d'ailleurs sur les circonstances de leur édition. Sur la base d'une étude comparative des trois versions du texte, qui met l'accent sur l'argumentation avancée chaque fois par l'auteur, nous formulons ici une série d'hypothèses pour l'interprétation de ce mystère, que nous allons examiner dans leurs détails à partir d'une étude de bibliologie qui suivra le présent article.

  16. Apprentissage par démonstrations : vaut-il la peine d'estimer une fonction de récompense?

    OpenAIRE

    Piot, Bilal; Geist, Matthieu; Pietquin, Olivier

    2013-01-01

    Cet article propose une étude comparative entre l'Apprentissage par Renforcement Inverse (ARI) et l'Apprentissage par Imitation (AI). L'ARI et l'AI sont deux cadres de travail qui utilisent le concept de Processus Décisionnel de Markov (PDM) et dans lesquels nous cherchons à résoudre le problème d'Apprentissage par Démonstrations (AD). L'AD est un problème où un agent appelé ap- prenti cherche à apprendre à partir de l'observation des démonstrations d'un autre agent appelé expert. Dans le cad...

  17. Caractéristiques anthropométriques d'enfants malnutris infectés par le VIH en Côte d'Ivoire

    OpenAIRE

    Beau, Jean-Pierre; Imboua-Coulibaly, L.

    1997-01-01

    Chez l'enfant, en plus, de l'amaigrissement, le retard de croissance en taille apparaît comme une complication fréquente au cours de l'infection par le VIH et l'objectif de cette étude est d'évaluer si l'existence d'un retard statural, apprécié par l'indice taille/âge, peut constituer un facteur discriminatoire chez l'enfant malnutri infecté par le VIH. Cette analyse rétrospective concerne 66 enfants âgés de plus de 15 mois, présentant une malnutrition de type marasme et suivis en 1994-1995 ...

  18. La mécanique des fluides numérique comme outil de positionnement d'un débimètre dans un réseau d'assainissement

    OpenAIRE

    Bonakdari, H.; LARRARTE, F

    2005-01-01

    Les prescriptions réglementaires et les impératifs techniques nécessitent une meilleure connaissance du fonctionnement réel des réseaux d'assainissement. Cette connaissance passe par celle de l'hydraulique d'une part et par celle des polluantstransportés d'autre part. Elle dépend de la capacité d'un point de mesure à donner des résultats représentatifs, et nécessite la définition de critères facilitant le choix de sites de mesure potentiels. Afin de définir ces paramètres, un protocole d'aide...

  19. Conception et mises a l'essai d'un environnement d'apprentissage integrant l'experimentation assistee par ordinateur et la simulation assistee par ordinateur

    Science.gov (United States)

    Riopel, Martin

    To make science laboratory sessions more instructive, we have developed a learning environment that will allow students enrolled in a mechanics course at college or university level to engage in a scientific modelization process by combining computer-simulated experimentation and microcomputer-based laboratories. The main goal is to assist and facilitate both inductive and deductive reasoning. Within this computer application, each action can also be automatically recorded and identified while the student is using the software. The most original part of the environment is to let the student compare the simulated animation with the real video by superposing the images. We used the software with students and observed that they effectively engaged in a modelization process that included both inductive and deductive reasoning. We also observed that the students were able to use the software to produce adequate answers to questions concerning both previously taught and new theoretical concepts in physics. The students completed the experiment about twice as fast as usual and considered that using the software resulted in a better understanding of the phenomenon. We conclude that this use of the computer in science education can broaden the range of possibilities for learning and for teaching and can provide new avenues for researchers who can use it to record and study students' path of reasoning. We also believe that it would be interesting to investigate more some of the benefits associated with this environment, particularly the acceleration effect, the improvement of students' reasoning and the equilibrium between induction and deduction that we observed within this research.

  20. suPAR: the molecular crystal ball

    DEFF Research Database (Denmark)

    Thunø, Maria; Macho, Betina; Eugen-Olsen, Jesper

    2009-01-01

    soluble urokinase Plasminogen Activator Receptor (suPAR) levels reflect inflammation and elevated suPAR levels are found in several infectious diseases and cancer. suPAR exists in three forms; suPAR(I-III), suPAR(II-III) and suPAR(I) which show different properties due to structural differences....... Studies suggest that full-length suPAR is a regulator of uPAR/uPA by actingas uPA-scavenger, whereas the cleaved suPAR(II-III) act as a chemotactic agent promoting the immune response via the SRSRY sequence in the linker-region. This review focus on the various suPAR fragments and their involvement...

  1. La structure de l'eau liquide: Une etude thermique par spectroscopie infrarouge

    Science.gov (United States)

    Larouche, Pascal

    Le probleme de la structure de l'eau liquide est important car l'eau est le liquide le plus present sur Terre, et complexe, la quete d'un modele precis pour decrire comment fonctionne ce liquide ayant debute des la fin du dix-neuvieme siecle. Cette etude aborde ce probleme en etudiant l'effet de l'augmentation de la temperature sur H2O et D 2O purs a l'aide de la spectroscopie infrarouge. L'intervalle de temperatures scrute est 29--93.1°C. Les spectres enregistres sont des spectres MIR-ATR entre 650 et 6000 cm-1 . L'analyse par facteurs de ces donnees permet de montrer que deux et seulement deux facteurs principaux sont necessaires pour decomposer tous les spectres experimentaux. Ces resultats sont confirmes grace a l'analyse par facteurs de spectres de la region FIR. Par la suite, la transformation en spectres de la partie reelle n et imaginaire k de l'indice de refraction permet de combiner les donnees des regions MIR et FIR. Une fois ce calcul termine, les spectres de transmission complets de H 2O et D2O entre 25 et 90°C sont connus. Ils sont ensuite utilises pour calculer par extrapolation le spectre des especes constituant l'eau liquide, puis leur abondance en fonction de la temperature. L'extrapolation de ces abondances montre que les especes correspondent a des temperatures limites de --18 et 122°C. Par la suite, la decomposition gaussienne des spectres d'especes met en evidence la riche structure de ces objets et permet de demontrer que l'apparent deplacement du massif d'absorption OH (OD) est produit par une variation de l'intensite des bandes et non pas de leur deplacement. L'examen attentif des spectres des especes prouve qu'il n'y a pas de OH libres crees par l'augmentation de la temperature: meme a 93.1°C, chaque molecule possede quatre liens-H. Ces conclusions sont de plus confirmees par une analyse thermodynamique du passage des molecules de la phase solide a la phase gazeuse. Pour diversifier la nature des resultats experimentaux utilises, des

  2. Contrôle d'une machine asynchrone par estimation robuste de la vitesse

    Science.gov (United States)

    Roboam, X.; Hapiot, J. C.; de Fornel, B.; Andrieux, C.

    1992-03-01

    This paper describes the study and the implementation of a variable speed drive for induction motor with no mechanical sensor. Power is supplied by a current-controlled voltage-source inverter. The lack of information (only two line-current sensors) requires an accurate and reliable reconstitution of the main quantities not sensed (flux, speed, torque). The results obtained show the excellent quality of the estimated speed, whatever the operating condition and despite the perturbations applied to the system. This study finally leads to the construction of a prototype. Cet article décrit l'étude et la mise en oeuvre d'un variateur de vitesse pour machine asynchrone sans capteur mécanique et alimentée par un onduleur de tension cotrôlé en courant. Le manque d'information (2 capteurs de courants de ligne uniquement) nécessite la reconstitution fiable et précise des grandeurs fondamentales non mesurées (flux, vitesse, couple). Les résultats obtenus montrent notamment l'excellente qualité de l'estimation de vitesse, quel que soit le point de fonctionnement et en dépit des perturbations auxquelles le système est soumis. Cette étude donne lieu à la réalisation d'un variateur prototype.

  3. The ParB-parS Chromosome Segregation System Modulates Competence Development in Streptococcus pneumoniae

    NARCIS (Netherlands)

    Attaiech, Laetitia; Minnen, Anita; Kjos, Morten; Gruber, Stephan; Veening, Jan-Willem

    2015-01-01

    UNLABELLED: ParB proteins bind centromere-like DNA sequences called parS sites and are involved in plasmid and chromosome segregation in bacteria. We previously showed that the opportunistic human pathogen Streptococcus pneumoniae contains four parS sequences located close to the origin of replicati

  4. Reconstruction de la surface de Fermi dans l'etat normal d'un supraconducteur a haute Tc: Une etude du transport electrique en champ magnetique intense

    Science.gov (United States)

    Le Boeuf, David

    Des mesures de resistance longitudinale et de resistance de Hall en champ magnetique intense transverse (perpendiculaire aux plans CuO2) ont ete effectuees au sein de monocristaux de YBa2Cu3Oy (YBCO) demacles, ordonnes et de grande purete, afin d'etudier l'etat fondamental des supraconducteurs a haute Tc dans le regime sous-dope. Cette etude a ete realisee en fonction du dopage et de l'orientation du courant d'excitation J par rapport a l'axe orthorhombique b de la structure cristalline. Les mesures en champ magnetique intense revelent par suppression de la supraconductivite des oscillations magnetiques des resistances longitudinale et de Hall dans YBa2Cu 3O6.51 et YBa2Cu4O8. La conformite du comportement de ces oscillations quantiques au formalisme de Lifshitz-Kosevich, apporte la preuve de l'existence d'une surface de Fermi fermee a caractere quasi-2D, abritant des quasiparticules coherentes respectant la statistique de Fermi-Dirac, dans la phase pseudogap d'YBCO. La faible frequence des oscillations quantiques, combinee avec l'etude de la partie monotone de la resistance de Hall en fonction de la temperature indique que la surface de Fermi d'YBCO sous-dope comprend une petite poche de Fermi occupee par des porteurs de charge negative. Cette particularite de la surface de Fermi dans le regime sous-dope incompatible avec les calculs de structure de bande est en fort contraste avec la structure electronique presente dans le regime surdope. Cette observation implique ainsi l'existence d'un point critique quantique dans le diagramme de phase d'YBCO, au voisinage duquel la surface de Fermi doit subir une reconstruction induite par l'etablissement d'une brisure de la symetrie de translation du reseau cristallin sous-jacent. Enfin, l'etude en fonction du dopage de la resistance de Hall et de la resistance longitudinale en champ magnetique intense suggere qu'un ordre du type onde de densite (DW) est responsable de la reconstruction de la surface de Fermi. L'analogie de

  5. Étude, définition et modèlisation d'un Système Distribué à Grande Échelle DIRAC - Distributed Infrastructure with Remote Agent Control

    CERN Document Server

    Garonne, V

    2005-01-01

    La physique des particules traite un grand nombre de données qui nécessitent des ressources de calculs particulièrement importantes. C'est pourquoi, les applications de simulation et d'analyse d'une expérience de physique des particules se retrouvent dans un environnement de calculs distribués à grande échelle. Souvent dénommés grilles, ces environnements se différencient des machines parallèles les ayant précédés par leurs natures intrinsèquement hétérogènes, partagées et fortement dynamiques. Ils se déclinent en deux types de système : les grilles institutionnelles qui mutualisent les ressources d'organismes par accord mutuel et les systèmes communautaires de calcul global dont le pair-à-pair est un exemple. Dans cette thèse, nous étudions ces systèmes et soulignons l'intérêt d'un système hybride conjuguant les deux approches. Nous proposons une implémentation d'un système unifié DIRAC (Distributed Infrastructure With Remote Agent Control). Cette solution est un système lég...

  6. Optic capture pars plana lensectomy

    Directory of Open Access Journals (Sweden)

    Lee JE

    2012-10-01

    Full Text Available Joo Eun LeeDepartment of Ophthalmology, Inje University College of Medicine, Busan, South KoreaObjective: To describe an optic capture pars plana lensectomy technique.Methods: After core vitrectomy, pars plana lensectomy is performed with preservation of the anterior capsule. Capsulorhexis is performed on the preserved anterior capsule through a 2.8 mm clear corneal incision. An intraocular lens (IOL is placed in the ciliary sulcus, and then the optic of the IOL is pushed back to the vitreous cavity so that the optic is captured by the surrounding capsulorhexis margin.Results: The captured IOL-capsule diaphragm remained stable during air–fluid exchange and prevented air prolapse to the anterior chamber. IOL stability and a clear visual axis were preserved during the follow-up period.Conclusion: With this modified pars plana lensectomy technique, stable IOL position and clear visual axis can be maintained when a pars plana approach is needed during combined cataract and vitreoretinal surgery.Keywords: lensectomy, optic capture, pars plana lensectomy, vitrectomy

  7. GESTION DES RISQUES ET DES INCERTITUDES L'EMERGENCE D'UN CONTRÔLE DE GESTION " PAR EXCEPTION "

    OpenAIRE

    Wegmann, Grégory

    2003-01-01

    International audience; Le thème de la gestion des risques a été peu abordé en contrôle de gestion et le fonctionnement des outils traditionnels comme les budgets postulent une maîtrise des risques et des incertitudes. L'émergence de nouvelles approches en contrôle de gestion montre une évolution sur ce point.

  8. Etude de l'oxydation d'un colorant organique AO7, par H2O2, en ...

    African Journals Online (AJOL)

    Abstract. The main objective of this work was to study the degradation of Acid Orange 7 (AO7) dye in an aqueous ... que les pesticides, d'où la nécessité de rechercher de meilleures alternatives. ..... Heteropolyblues: Relationship between metal-oxygen-metal bridges and ... 7 Using Ti/RuO2-Pt Electrode, Int. J. Electrochem.

  9. MODELISATION MULTI-AGENTS D'UN SERVICE ECOSYSTEMIQUE : SCENARIOS DE SYSTEMES D'EQUARRISSAGE PAR DES RAPACES NECROPHAGES

    OpenAIRE

    Dupont, Helene

    2011-01-01

    The vulture's conservation relies in part on the management of their trophic resources, which is, in Europe, largely linked to farming activities and constrained by sanitary regulations. However, through scavenging, vultures provide ecosystem services. Hence, feeding them can be seen as a beneficial activity both preserving these flagship species and maintaining the services they offer. We conducted an interdisciplinary framework on the "natural carcass removal" (i.e. by vultures), coupling s...

  10. Cartographie 3D et localisation par vision monoculaire pour la navignation autonome d'un robot mobile

    OpenAIRE

    Royer, Eric

    2006-01-01

    This thesis presents the realization of a localization system for a mobile robot relying on monocular vision. The aim of this project is to be able to make a robot follow a path in autonomous navigation in an urban environment. First, the robot is driven manually. During this learning step, the on board camera records a video sequence. After an off-line processing step, an image taken with the same hardware allows to compute the pose of the robot in real-time. This localization can be used to...

  11. Essai d'une table non-vibrante par enregistrement du mouvement brownien d'un galvanomètre

    NARCIS (Netherlands)

    Rottier, P.B.; Jansen, M.T.

    1951-01-01

    Attempts to attain the natural limit of the sensitivity of a galvanometer, viz. the Brownian movement, have at first been unsuccessful in our institute. Neither a heavy slab of stone attached to an outer wall, nor a masonry of 1800 kg in the cellar embedded in a layer of sand 10 cm thick gave our th

  12. GESTION DES RISQUES ET DES INCERTITUDES L'EMERGENCE D'UN CONTRÔLE DE GESTION " PAR EXCEPTION "

    OpenAIRE

    Wegmann, Grégory

    2003-01-01

    International audience; Le thème de la gestion des risques a été peu abordé en contrôle de gestion et le fonctionnement des outils traditionnels comme les budgets postulent une maîtrise des risques et des incertitudes. L'émergence de nouvelles approches en contrôle de gestion montre une évolution sur ce point.

  13. Regulation biologique du meiobenthos d'un ecosysteme lagunaire par un alevinage experimental en soles (Solea vualgaris )

    OpenAIRE

    Castel, J.; Lasserre, P.

    1982-01-01

    The "fish reservoirs" of the Arcachon Basin (France) are artificial ponds created in lagoonal marshes. Opportunistic populations of microorganisms and of meiofauna increase the tendency to create dystrophic crisis. Fry stocking of soles (Solea vulgaris ) into the fish ponds have been made to estimate the influence of the predatory activity and bioturbation on the food web. For 10 soles/m super(2), the abundance of opportunistic populations of meiofauna decreases and this result indicates a mo...

  14. Observation et commande par retour d'état d'un procédé de bacs communicants

    OpenAIRE

    Hably, Ahmad; Dumon, Jonathan

    2011-01-01

    International audience; Cet article présente une maquette pédagogique composée des trois bacs communicants. Une approche basée sur la représentation d'état est développée pour observer et asservir les niveaux d'eau dans les trois bacs. Les résultats sont validés en simulation et en pratique.

  15. Identification d'un processus autor\\'{e}gressif gaussien stable par la m\\'{e}thode de moyennisation logarithmique

    OpenAIRE

    Chaabane, Faouzi; Fathallah, Hamdi

    2006-01-01

    In the present work, we consider a stable one-dimensional gaussian autoregressive model in continous time. Using the limit theorems with logarithmic averaging obtained for continous local martingales, we construct then an estimator of the noise covariance $\\sigma^{2}$ and an estimator of $\\theta$ different of the one of the least squares estimator. By exploiting the weighting method we ameliorate the convergence rates of these new estimators.

  16. Commande de vol non lineaire d'un drone a voilure fixe par la methode du backstepping

    Science.gov (United States)

    Finoki, Edouard

    This thesis describes the design of a non-linear controller for a UAV using the backstepping method. It is a fixed-wing UAV, the NexSTAR ARF from HobbicoRTM. The aim is to find the expressions of the aileron, the elevator, and the rudder deflection in order to command the flight path angle, the heading angle and the sideslip angle. Controlling the flight path angle allows a steady, climb or descent flight, controlling the heading cap allows to choose the heading and annul the sideslip angle allows an efficient flight. A good technical control has to ensure the stability of the system and provide optimal performances. Backstepping interlaces the choice of a Lyapunov function with the design of feedback control. This control technique works with the true non-linear model without any approximation. The procedure is to transform intermediate state variables into virtual inputs which will control other state variables. Advantages of this technique are its recursivity, its minimum control effort and its cascaded structure that allows dividing a high order system into several simpler lower order systems. To design this non-linear controller, a non-linear model of the UAV was used. Equations of motion are very accurate, aerodynamic coefficients result from interpolations between several essential variables in flight. The controller has been implemented in Matlab/Simulink and FlightGear.

  17. Conception d'un système de veille : une approche par le concept d'environnement pertinent

    OpenAIRE

    Marcon, Christian

    2001-01-01

    International audience; The effectiveness of any business intelligence system is directly correlated to the degree of ownership of the information provided by the key decision makers in the organization. The quality of the interaction between the intelligence system and decision system is therefore crucial. This interaction strongly depends on the attention that policymakers attach to information they receive, so the concordance between this information and their interests. The approach prese...

  18. Overarching: Duns Scotus and Edith Stein on Individuality and Individuation Problem

    Directory of Open Access Journals (Sweden)

    Carmen Cozma

    2012-05-01

    Full Text Available Book review to: Francesco Alfieri, OFM. La presenza di Duns Scoto nel pensiero di Edith Stein. La questione dell’individualità. Roma: Pontificia Universitas Lateranensis, 2011. Pp. 331.

  19. BUENA FORTUNA Y LIBERTAD EN QUODLIBETALES XXI DE DUNS ESCOTO

    OpenAIRE

    Elías, Gloria Silvana

    2014-01-01

    Durante la Edad Media, uno de los temas más controversiales debatidos en las universidades de Artes y Teología del siglo XIII europeo, fue la relación posible entre la fortuna y la libertad, discusión ésta fomentada por la circulación de un opúsculo que se adjudicaba a Aristóteles, denominado De bona fortuna. En la cuestión XXI de Quaestiones quodlibetales, Duns Escoto -apoyándose en tal apócrifo- analiza qué es lo que el Estagirita entiende por fortuna, y qué relación cabe con la causa del q...

  20. Entrainment Reduction and Additional Dissipation in Dilute Polymer Solutions

    Science.gov (United States)

    Holzner, Markus; Lüthi, Beat; Liberzon, Alexander; Guala, Michele; Kinzelbach, Wolfgang

    We present a comparative experimental study of a turbulent flow developing in clear water and dilute polymer solutions (25 and 50 wppm polyethylene oxide). The flow is forced by a planar grid that oscillates vertically in a square container of initially still fluid. The two-component velocity fields are measured in a vertical plane passing through the center of the tank by using time resolved Particle Image Velocimetry (PIV).We obtain a lower entrainment rate for polymer solutions as compared to clear water. Extending arguments based on similarity and fractal theory to the case of dilute polymer solutions, we derive a relation between the entrainment rate and the fraction of input energy dissipated by the polymers.

  1. Bubble size distribution in surface wave breaking entraining process

    Institute of Scientific and Technical Information of China (English)

    HAN; Lei; YUAN; YeLi

    2007-01-01

    From the similarity theorem,an expression of bubble population is derived as a function of the air entrainment rate,the turbulent kinetic energy (TKE) spectrum density and the surface tension.The bubble size spectrum that we obtain has a dependence of a-2.5+nd on the bubble radius,in which nd is positive and dependent on the form of TKE spectrum within the viscous dissipation range.To relate the bubble population with wave parameters,an expression about the air entrainment rate is deduced by introducing two statistical relations to wave breaking.The bubble population vertical distribution is also derived,based on two assumptions from two typical observation results.

  2. Mass entrainment rate of an ideal momentum turbulent round jet

    DEFF Research Database (Denmark)

    Medrano, Fermın Franco; Fukumoto, Yasuhide; Velte, Clara Marika;

    2017-01-01

    We propose a two-phase-fluid model for a full-cone turbulent round jet that describes its dynamics in a simple but comprehensive manner with only the apex angle of the cone being a disposable parameter. The basic assumptions are that (i) the jet is statistically stationary and that (ii) it can...... of the distance from the nozzle, from which the dynamic pressure and the mass entrainment rate are calculated. Assuming a far-field approximation, we theoretically derive a constant entrainment rate coefficient solely in terms of the cone angle. Moreover, we carry out experiments for a single-phase turbulent air...... jet and show that the predictions of our model compare well with this and other experimental data of atomizing liquid jets....

  3. Mixing and entrainment in hydraulically driven stratified sill flows

    DEFF Research Database (Denmark)

    Nielsen, Morten Holtegaard; Pratt, Larry; Helfrich, Karl

    2004-01-01

    that the reduced gravity model systematically underestimates inertia and overestimates buoyancy. These differences are quantified by shape coefficients that measure the vertical non-uniformities of the density and horizontal velocity that arise, in part, by incomplete mixing of entrained mass and momentum over...... model. Self-similarity is not observed in the numerically generated flow, but the observed critical section continues to lie upstream of the location predicted by the reduced gravity model. The factors influencing this result are explored.......The investigation involves the hydraulic behaviour of a dense layer of fluid flowing over an obstacle and subject to entrainment of mass and momentum from a dynamically inactive (but possibly moving) overlying fluid. An approach based on the use of reduced gravity, shallow-water theory with a cross...

  4. A new technology for air-entrainment of concrete

    DEFF Research Database (Denmark)

    Laustsen, Sara; Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    2008-01-01

    reservoirs are distributed throughout the concrete. During the hydration process the cement paste imbibes water from the water-filled SAP voids. Thereby the water-filled SAP voids turn into partly air-filled voids. The advantages of the SAP-based technology compared to traditional chemical air......This paper describes a new technology for air-entrainment of concrete. The technology is based on the addition of dry superabsorbent polymers (SAP) to the concrete. A large amount of small internal water reservoirs are formed during mixing when SAP absorbs water and swells. The internal water......-entrainment include stability of the air void system and improved control of both the amount of added air and the air void size. The new technology based on SAP has been tested in freeze-thaw experiments, where the amount of surface scaling was measured. The results clearly show that SAP is beneficial for frost...

  5. An entrainment model for the turbulent jet in a coflow

    Science.gov (United States)

    Enjalbert, Nicolas; Galley, David; Pierrot, Laurent

    2009-09-01

    The entrainment hypothesis was introduced by G.I. Taylor to describe one-dimensionally the development of turbulent jets issuing into a stagnant or coflowing environment. It relates the mass flow rate of surrounding fluid entrained into the jet to the characteristic velocity difference between the jet and the coflow. A model based on this hypothesis along with axial velocity assumed to follow a realistic Gaussian distribution is presented. It possesses an implicit analytical solution, and its results are compared and shown to be fully equivalent to previously published models that are rather based on a spreading hypothesis. All of them are found to be in agreement with experimental results, on a wide range of downstream positions and for various coflow intensities. To cite this article: N. Enjalbert et al., C. R. Mecanique 337 (2009).

  6. Axially symmetric equations for differential pulsar rotation with superfluid entrainment

    CERN Document Server

    Antonelli, Marco

    2016-01-01

    We propose an analytical two-components model for pulsar rotational dynamics: the aim is to reduce the 3D hydrodynamical problem to a 1D (radial) problem, using the hypothesis of negligible azimuthal inhomogeneities. The result is the construction of a computationally simple model that takes into account for the non-uniform structure of the star, entrainment effect and differential rotation of the superfluid component. For the first time all these ingredients are treated in a fully consistent way within the picture provided by our initial hypotheses. Our treatment clarifies which are the physical inputs needed to build, to current knowledge, more realistic simulations of rotating neutron stars and gives a neat description of the effect of entrainment when straight vortex lines are considered. Moreover, on this basis, we briefly introduce a new method that can be used to put a constraint to the mass of the pulsars that display very large glitches and to the relative spin up timescales.

  7. Numerical Modeling of Deep Mantle Flow: Thermochemical Convection and Entrainment

    Science.gov (United States)

    Mulyukova, Elvira; Steinberger, Bernhard; Dabrowski, Marcin; Sobolev, Stephan

    2013-04-01

    One of the most robust results from tomographic studies is the existence of two antipodally located Large Low Shear Velocity Provinces (LLSVPs) at the base of the mantle, which appear to be chemically denser than the ambient mantle. Results from reconstruction studies (Torsvik et al., 2006) infer that the LLSVPs are stable, long-lived, and are sampled by deep mantle plumes that rise predominantly from their margins. The origin of the dense material is debated, but generally falls within three categories: (i) a primitive layer that formed during magma ocean crystallization, (ii) accumulation of a dense eclogitic component from the recycled oceanic crust, and (iii) outer core material leaking into the lower mantle. A dense layer underlying a less dense ambient mantle is gravitationally stable. However, the flow due to thermal density variations, i.e. hot rising plumes and cold downwelling slabs, may deform the layer into piles with higher topography. Further deformation may lead to entrainment of the dense layer, its mixing with the ambient material, and even complete homogenisation with the rest of the mantle. The amount of the anomalous LLSVP-material that gets entrained into the rising plumes poses a constraint on the survival time of the LLSVPs, as well as on the plume buoyancy, on the lithospheric uplift associated with plume interaction and geochemical signature of the erupted lavas observed at the Earth's surface. Recent estimates for the plume responsible for the formation of the Siberian Flood Basalts give about 15% of entrained dense recycled oceanic crust, which made the hot mantle plume almost neutrally buoyant (Sobolev et al., 2011). In this numerical study we investigate the mechanics of entrainment of a dense basal layer by convective mantle flow. We observe that the types of flow that promote entrainment of the dense layer are (i) upwelling of the dense layer when it gets heated enough to overcome its stabilizing chemical density anomaly, (ii

  8. Improvements and applications of entrainment control for nonlinear dynamical systems.

    Science.gov (United States)

    Liu, Fang; Song, Qiang; Cao, Jinde

    2008-12-01

    This paper improves the existing entrainment control approaches and develops unified schemes to chaos control and generalized (lag, anticipated, and complete) synchronization of nonlinear dynamical systems. By introducing impulsive effects to the open-loop control method, we completely remove its restrictions on goal dynamics and initial conditions, and derive a sufficient condition to estimate the upper bound of impulsive intervals to ensure the global asymptotic stability. We then propose two effective ways to implement the entrainment strategy which combine open-loop and closed-loop control, and we prove that the feedback gains can be chosen according to a lower bound or be tuned with an adaptive control law. Numerical examples are given to verify the theoretical results and to illustrate their applications.

  9. Effects of entrainment and mixing on droplet size distributions in warm cumulus clouds

    Science.gov (United States)

    Tölle, Merja H.; Krueger, Steven K.

    2014-06-01

    A long-standing problem in cloud physics is the broadening of the cloud droplet spectrum in warm cumulus clouds. To isolate the changes of the droplet size distribution (DSD) due to entrainment and turbulent mixing, we used the Explicit Mixing Parcel Model (EMPM). The EMPM explicitly represents spatial variability due to entrainment and turbulent mixing down to the smallest turbulence scales in a one-dimensional domain. Several thousand individual droplets evolve by condensation or evaporation according to their local environments. We used EMPM results to characterize the evolution of the DSD due to entrainment and isobaric mixing for a wide range of conditions in a 20 m domain, including variations in entrained environmental air fraction, the turbulence dissipation rate, the size of the entrained blobs, and the relative humidity of the entrained air. We found that the broadening of the DSD due to entrainment and isobaric mixing for a specific value of the entrained air relative humidity depends only on the eddy mixing time scale and the LWC after mixing. Broadening increases substantially as the evaporation time scale decreases due to decreasing relative humidity of the entrained air. Our results also show that it is possible to parameterize the effects of entrainment and mixing on the droplet number concentration. The comprehensive results obtained for one set of values of entrained air relative humidity, droplet size, and droplet concentration should be extended to other values.

  10. Yeast Dun1 Kinase Regulates Ribonucleotide Reductase Small Subunit Localization in Response to Iron Deficiency.

    Science.gov (United States)

    Sanvisens, Nerea; Romero, Antonia M; Zhang, Caiguo; Wu, Xiaorong; An, Xiuxiang; Huang, Mingxia; Puig, Sergi

    2016-04-29

    Ribonucleotide reductase (RNR) is an essential iron-dependent enzyme that catalyzes deoxyribonucleotide synthesis in eukaryotes. Living organisms have developed multiple strategies to tightly modulate RNR function to avoid inadequate or unbalanced deoxyribonucleotide pools that cause DNA damage and genome instability. Yeast cells activate RNR in response to genotoxic stress and iron deficiency by facilitating redistribution of its small heterodimeric subunit Rnr2-Rnr4 from the nucleus to the cytoplasm, where it forms an active holoenzyme with large Rnr1 subunit. Dif1 protein inhibits RNR by promoting nuclear import of Rnr2-Rnr4. Upon DNA damage, Dif1 phosphorylation by the Dun1 checkpoint kinase and its subsequent degradation enhances RNR function. In this report, we demonstrate that Dun1 kinase triggers Rnr2-Rnr4 redistribution to the cytoplasm in response to iron deficiency. We show that Rnr2-Rnr4 relocalization by low iron requires Dun1 kinase activity and phosphorylation site Thr-380 in the Dun1 activation loop, but not the Dun1 forkhead-associated domain. By using different Dif1 mutant proteins, we uncover that Dun1 phosphorylates Dif1 Ser-104 and Thr-105 residues upon iron scarcity. We observe that the Dif1 phosphorylation pattern differs depending on the stimuli, which suggests different Dun1 activating pathways. Importantly, the Dif1-S104A/T105A mutant exhibits defects in nucleus-to-cytoplasm redistribution of Rnr2-Rnr4 by iron limitation. Taken together, these results reveal that, in response to iron starvation, Dun1 kinase phosphorylates Dif1 to stimulate Rnr2-Rnr4 relocalization to the cytoplasm and promote RNR function.

  11. Entrainment of cell division in phytoplankton with dynamic energy budgets

    Science.gov (United States)

    Muller, Erik B.; Ananthasubramaniam, Bharath; Klanjšček, Tin; Nisbet, Roger M.

    2011-11-01

    We explore the entrainment behavior of cell division in phytoplankton in the context of Dynamic Energy Budget (DEB) theory. In particular, we explore the range of DEB and environmental parameter values within which a cell divides at regular intervals in a periodic light environment with abundant nutrients and investigate the impact of parameter values on the phase of cell division. We consider three types of cells that differ in the evolution of surface area to volume ratio during the cell cycle: cells with a constant shape (isomorphs), cells with a constant surface area (V0-morphs) and cells with a constant surface area to volume ratio (V1-morphs), the latter being the default choice in studies on the population dynamics of unicellular organisms because of its desirable mathematical implications. Only in isomorphs and V0-morphs, however, cell division can be entrained to a periodic light. Regular cell division in V1 is purely coincidental, as it depends on exact choices for parameter values. We attribute this to the fact that V1-morphs lack the negative feedback of size on the dynamics of reserves in V0-morphs and isomorphs. Because entrained isomorphs and V0-morphs divide during the dark hours in our simulations, these two shapes can represent the division behavior of phytoplankton species that complete the cell cycle during the night, such as dinoflagellates and coccolithophores. A description of the division behavior of species completing the cell cycle during the day, such as silicon dependent diatoms and cyanobacteria, requires a more complex model than used in this paper. Furthermore, we explore the robustness of our findings by randomizing model parameters and introducing unevenness in biomass separation between daughter cells during cell division. We conclude that especially the entrainment in V0-morphs is relatively insensitive to perturbations.

  12. Persistence, entrainment, and function of circadian rhythms in polar vertebrates.

    Science.gov (United States)

    Williams, Cory T; Barnes, Brian M; Buck, C Loren

    2015-03-01

    Polar organisms must cope with an environment that periodically lacks the strongest time-giver, or zeitgeber, of circadian organization-robust, cyclical oscillations between light and darkness. We review the factors influencing the persistence of circadian rhythms in polar vertebrates when the light-dark cycle is absent, the likely mechanisms of entrainment that allow some polar vertebrates to remain synchronized with geophysical time, and the adaptive function of maintaining circadian rhythms in such environments.

  13. Air entrainment by a plunging jet under intermittent vortex conditions

    OpenAIRE

    Kim, Kevin Jin; Corfman, Kyle; Li, Kevin; Kiger, Ken T.

    2011-01-01

    This fluid dynamic video entry to the 2011 APS-DFD Gallery of Fluid Motion details the transient evolution of the free surface surrounding the impact region of a low-viscosity laminar liquid jet as it enters a quiescent pool. The close-up images depict the destabilization and breakup of the annular air gap and the subsequent entrainment of bubbles into the bulk liquid.

  14. La gestion par affaire et pilotage de la performance des organisations industrielles

    OpenAIRE

    Pendariees, Michel

    2006-01-01

    International audience; « Dans les systèmes industriels où les produits sont conçus et réalisés en fonction des spécifications des clients, la notion d'affaire est l'entité de base de la gestion industrielle » . Aujourd'hui, la recherche de solutions globales « sur mesure », prime sur la fourniture d'un catalogue de « belles solutions », comme réponse au client. Pour être performante, l'entreprise industrielle doit s'organiser par « affaire ». Ce qui lui permet de mieux s'adapter et maîtriser...

  15. Cancer bronchique à petites cellules et grossesse: à propos d'un cas avec revue de la literature

    Science.gov (United States)

    Safini, Fatima; Jjouhadi, Hassan; Chehal, Asmaa; Mernissi, Farida; Wilfried, Akpoo; Bouchbika, Zineb; Taleb, Amina; Benchakroun, Nadia; Tawfiq, Nezha; Sahraoui, Souha; Benider, Abdellatif

    2016-01-01

    Le cancer broncho-pulmonaire (CBP) de la femme enceinte est une entité rare, d’évolution péjorative. Cette situation devient de plus en plus fréquente, du fait de l'augmentation du tabagisme chez la femme. La transmission tumorale trans-placentaire avec atteinte fœtale est décrite surtout chez les femmes non traitées. Le traitement est multidisciplinaire et n'est pas bien codifié. Nous rapportons le cas d'une patiente de 23 ans chez qui le diagnostic d'un carcinome bronchique à petites cellules a été fait au cours de sa grossesse. Elle avait bénéficié d'une chimiothérapie pendant la grossesse, bien tolérée. L’évaluation radiologique a objectivé une stabilisation du processus pulmonaire. Le traitement a été complété par une association radio-chimiothérapie concomitante après l'accouchement. PMID:27279957

  16. Optimisation des conditions de fonctionnement d'un pilote plasma de 25kW pour la purification du silicium

    Science.gov (United States)

    Erin, J.; Morvan, D.; Amouroux, J.

    1995-05-01

    The development of the silicon purification process by melting under reactive thermal plasma, in progress to industrial transfer (100 kW level), requires to take into account the best energetic conditions to achieve a material with good photovoltaic properties. This study concerns the energy balance of a plasma pilot at 25 kW. the results point out the effect of gas composition (Ar or Ar-H{2}) and gas injection mode in the plasma torch (single or double flow) on the energy conversion and melting rate. Le développement du procédé de purification du silicium par fusion sous plasma thermique réactif, en cours de transfert industriel, exige de fixer les conditions énergétiques optimales de fonctionnement tout en respectant l'objectif qui consiste à élaborer un matériau présentant les meilleures photovoltaïques. L'étude présentée concerne les bilans énergétiques d'un pilote plasma de 25 kW. Les résultats soulignent le rôle de la composition du mélange plasmagène (Ar ou Ar-H{2}) et du mode d'injection des gaz dans l'applicateur plasma (simple ou double flux) vis à vis du rendement énergétique et de la vitesse de fusion.

  17. Préparation conditionnelle d'un état en régime de variables continues : génération expérimentale d'un état non-classique à partir de faisceaux jumeaux

    Science.gov (United States)

    Laurat, J.; Coudreau, T.; Treps, N.; Maître, A.; Fabre, C.

    2004-11-01

    Ce travail constitue la première démonstration expérimentale de préparation conditionnelle d'un état non-classique dans le domaine des variables continues. A partir d'un OPO de type II qui génère au dessus du seuil des faisceaux signal et complémentaire fortement corrélés en intensité, les valeurs de l'intensité du signal sont conservées uniquement lorsque le complémentaire prend une valeur comprise dans une bande plus petite que son écart-type. Par cette technique très simple, nous avons généré un état sub-Poissonien 4.4 dB (64%) sous le bruit quantique standard à partir de faisceaux jumeaux présentant une réduction du bruit sur leur différence d'intensité de 7.5 dB (82%).

  18. Designing Tone Reservation PAR Reduction

    Directory of Open Access Journals (Sweden)

    Johansson Albin

    2006-01-01

    Full Text Available Tone reservation peak-to-average (PAR ratio reduction is an established area when it comes to bringing down signal peaks in multicarrier (DMT or OFDM systems. When designing such a system, some questions often arise about PAR reduction. Is it worth the effort? How much can it give? How much does it give depending on the parameter choices? With this paper, we attempt to answer these questions without resolving to extensive simulations for every system and every parameter choice. From a specification of the allowed spectrum, for instance prescribed by a standard, including a PSD-mask and a number of tones, we analytically predict achievable PAR levels, and thus implicitly suggest parameter choices. We use the ADSL2 and ADSL2+ systems as design examples.

  19. Constant darkness restores entrainment to phase-delayed Siberian hamsters.

    Science.gov (United States)

    Ruby, Norman F; Joshi, Nirav; Heller, H Craig

    2002-12-01

    Over 90% of Siberian hamsters (Phodopus sungorus) fail to reentrain to a 5-h phase delay of a 16:8-h photocycle. Because constant darkness (DD) restores rhythms disrupted by constant light, we tested whether DD could also restore entrainment. DD began 0, 5, or 14 days after a 5-h phase delay, and the light-dark cycle was reinstated 14 days later. All hamsters exposed to DD on day 0 reentrained, whereas 42% reentrained irrespective of whether DD began 5 or 14 days later. For these latter two groups, tau (tau) and alpha (alpha) in DD predicted reentrainment; animals that reentrained had a mean tau and alpha of 24.1 and 8.9 h, respectively, whereas those that failed to reentrain maintained a mean tau and alpha of 25.0 and of 7.1 h, respectively. Restoration of entrainment by DD is somewhat paradoxical because it suggests that reentrainment to the photocycle was prevented by continued exposure to that same photocycle. The dichotomy of circadian responses to DD suggests "entrainment" phenotypes that are similar to those of photoperiodic responders and nonresponders.

  20. Air entrainment in open channel flows. Application to spillways

    Energy Technology Data Exchange (ETDEWEB)

    Chanson, H. (Queensland Univ., St. Lucia (Australia))

    1992-01-01

    In open channel flows an important design parameter is the amount of entrained air. The presence of air in high velocity flows or steep chutes increases the bulk of the flow and this is a design parameter that determines the height of chute sidewalls. Furthermore the presence of air within the boundary layer reduces the shear stress between flow layers and hence the shear forces. The resulting increase of fluid motion must be taken in account when designing ski jump and stilling basin downstream of a spillway. Besides the presence of air within high-velocity flows may prevent or reduce cavitation damage. Estimation of the quantity of air entrained along the spillway is required by the design engineer when sitting aerators to artificially introduce more air, or determining whether aerators are required. Recently air entrainment on chutes also been recognized for its contribution to air-water transfer of atmospheric gases such as oxygen and nitrogen. This article describes a general method to compute the flow characteristics of self-aerated flows. Firstly the uniform flow conditions are presented and comparisons will be made between model and prototype results. Then the basic equations for gradually varied aerated flows will be developed, and these results are discussed and compared with experimental data. 28 refs., 8 figs., 3 tabs.

  1. Bubble entrainment, spray and splashing at hydraulic jumps

    Institute of Scientific and Technical Information of China (English)

    CHANSON Hubert

    2006-01-01

    The sudden transition from a high-velocity, supercritical open channel flow into a slow-moving sub-critical flow is a hydraulic jump. Such a flow is characterised by a sudden rise of the free-surface, with some strong energy dissipation and air entrainment, waves and spray. New two-phase flow measurements were performed in the developing flow region using a large-size facility operating at large Reynolds numbers. The experimental results demonstrated the complexity of the flow with a developing mixing layer in which entrained bubbles are advected in a high shear stress flow. The relationship between bubble count rates and void fractions was non-unique in the shear zone, supporting earlier observations of some form of double diffusion process between momentum and air bubbles. In the upper region, the flow consisted primarily of water drops and packets surrounded by air. Visually significant pray and splashing were significant above the jump roller. The present study is the first comprehensive study detailing the two-phase flow properties of both the bubbly and spray regions of hydraulic jumps, a first step towards understanding the interactions between bubble entrainment and droplet ejection processes.

  2. Entrainment of respiratory frequency to exercise rhythm during hypoxia.

    Science.gov (United States)

    Paterson, D J; Wood, G A; Marshall, R N; Morton, A R; Harrison, A B

    1987-05-01

    Breathing frequency (f) is often reported as having an integer-multiple relationship to limb movement (entrainment) during rhythmic exercise. To investigate the strength of this coupling while running under hypoxic conditions, two male Caucasians and four male Nepalese porters were tested in the Annapurna region of the Himalayas at altitudes of 915, 2,135, 3,200, 4,420, and 5,030 m. In an additional study in a laboratory at sea level, three male and four female subjects inspired various O2-N2 mixtures [fraction of inspired O2 (FIO2) = 20.93, 17.39, 14.40, 11.81%] that were administered in a single-blind randomized fashion during a treadmill run (40% FIO2 maximum O2 consumption). Breathing and gait signals were stored on FM tape and later processed on a PDP 11/73 computer. The subharmonic relationships between these signals were determined from Fourier analysis (power spectrum), and the coincidence of coupling occurrence was statistically modeled. Entrainment decreased linearly during increasing hypoxia (P less than 0.01). Moreover, a significant linear increase in f occurred during hypoxia (P less than 0.05), whereas stride frequency and metabolic rate remained constant, suggesting that hypoxic-induced increases in f decreased the degree of entrainment.

  3. Entrainment and stimulated emission of ultrasonic piezoelectric auto-oscillators.

    Science.gov (United States)

    Weaver, Richard L; Lobkis, Oleg I; Yamilov, Alexey

    2007-12-01

    Theoretical modeling and laboratory tests are conducted for nonlinear auto-oscillating piezoelectric ultrasonic devices coupled to reverberant elastic bodies. The devices are shown to exhibit behavior familiar from the theory of coupled auto-oscillators. In particular, these spontaneously emitting devices adjust their limit-cycle frequency to the spectrum of the body. It is further shown that the auto-oscillations can be entrained by an applied field; an incident wave at a frequency close to the frequency of the natural limit cycle entrains the oscillator. Special attention is paid to the phase of entrainment. Depending on details, the phase is such that the oscillator can be in a state of stimulated emission: the incident field amplifies the ultrasonic power emitted by the oscillator. These behaviors are essential to eventual design of an ultrasonic system that would consist of a number of such devices all synchronized to their mutual field, a system that would be an analog to a laser. A prototype uaser is constructed.

  4. Stratocumulus Precipitation and Entrainment Experiment (SPEE) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Bruce [Univ. of Miami, Miami, FL (United States); Ghate, Virendra [Argonne National Lab. (ANL), Argonne, IL (United States); CADeddu, Maria [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-06-01

    The scientific focus of this project was to examine precipitation and entrainment processes in marine stratocumulus clouds. The entrainment studies focused on characterizing cloud turbulence at cloud top using Doppler cloud radar observations. The precipitation studies focused on characterizing the precipitation and the macroscopic properties (cloud thickness, and liquid water path) of the clouds. This project will contribute to the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s overall objective of providing the remote-sensing observations needed to improve the representation of key cloud processes in climate models. It will be of direct relevance to the components of ARM dealing with entrainment and precipitation processes in stratiform clouds. Further, the radar observing techniques that will be used in this study were developed using ARM Southern Great Plains (SGP) facility observations under Atmospheric System Research (ASR) support. The observing systems operating automatously from a site located just north of the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) aircraft hangar in Marina, California during the period of 1 May to 4 November 2015 included: 1. Microwave radiometer: ARM Microwave Radiometer, 3-Channel (MWR3C) with channels centered at 23.834, 30, and 89 GHz; supported by Dr. Maria Cadeddu. 2. Cloud Radar: CIRPAS 95 GHz Frequency Modulated Continuous Wave (FMCW) Cloud Radar (Centroid Frequency Chirp Rate [CFCR]); operations overseen by Drs. Ghate and Albrecht. 3. Ceilometer: Vaisala CK-14; operations overseen by Drs. Ghate and Albrecht.

  5. CREB influences timing and entrainment of the SCN circadian clock.

    Science.gov (United States)

    Lee, Boyoung; Li, Aiqing; Hansen, Katelin F; Cao, Ruifeng; Yoon, Jae Hwa; Obrietan, Karl

    2010-12-01

    The transcriptional feedback circuit, which is at the core of the suprachiasmatic nucleus (SCN) circadian (i.e., 24 h) clock, is tightly coupled to both external entrainment cues, such as light, as well as rhythmic cues that arise on a system-wide level within the SCN. One potential signaling pathway by which these cues are conveyed to the molecular clock is the CREB/CRE transcriptional cascade. In this study, we employed a tetracycline-inducible CREB repressor mouse strain, in which approximately 60% of the SCN neurons express the transgene, to test CREB functionality in the clock and its effects on overt rhythmicity. We show that attenuated CREB signaling in the SCN led to a significant reduction in light-evoked clock entrainment. An examination of circadian timing revealed that CREB repressor mice exhibited normal free-running rhythms in the absence of external lighting cues. However, under conditions of constant light, which typically leads to a lengthening of the circadian period, CREB repressor mice exhibited a dramatic arrhythmic phenotype, which could be reversed with doxycycline. At a cellular level, the repression of CREB led to a significant reduction in both the expression of the circadian clock proteins PERIOD1 and PERIOD2 and the clock output hormones AVP and VIP. Together, these data support the idea that the CRE transcriptional pathway orchestrates transcriptional events that are essential for both the maintenance of SCN timing and light entrainment of the circadian clock.

  6. Entrainment of coarse grains using a discrete particle model

    Energy Technology Data Exchange (ETDEWEB)

    Valyrakis, Manousos, E-mail: Manousos.Valyrakis@glasgow.ac.uk [Lecturer in Water and Environmental Engineering, Rankine 817b, University of Glasgow, Glasgow G12 8LT (United Kingdom); Arnold, Roger B. Jr. [Environmental Engineer, Arcadis, USA (formerly: research assistant Virginia Tech, USA) (United States)

    2014-10-06

    Conventional bedload transport models and incipient motion theories relying on a time-averaged boundary shear stress are incapable of accounting for the effects of fluctuating near-bed velocity in turbulent flow and are therefore prone to significant errors. Impulse, the product of an instantaneous force magnitude and its duration, has been recently proposed as an appropriate criterion for quantifying the effects of flow turbulence in removing coarse grains from the bed surface. Here, a discrete particle model (DPM) is used to examine the effects of impulse, representing a single idealized turbulent event, on particle entrainment. The results are classified according to the degree of grain movement into the following categories: motion prior to entrainment, initial dislodgement, and energetic displacement. The results indicate that in all three cases the degree of particle motion depends on both the force magnitude and the duration of its application and suggest that the effects of turbulence must be adequately accounted for in order to develop a more accurate method of determining incipient motion. DPM is capable of simulating the dynamics of grain entrainment and is an appropriate tool for further study of the fundamental mechanisms of sediment transport.

  7. Circadian entrainment and its role in depression: a mechanistic review.

    Science.gov (United States)

    Lall, G S; Atkinson, L A; Corlett, S A; Broadbridge, P J; Bonsall, D R

    2012-10-01

    The natural rotation of the earth generates an environmental day-night cycle that repeats every 24 h. This daily transition from dawn to dusk provides one of the most important time cues to which the majority of organisms synchronise their activity. Under these conditions, natural light, a photic stimulus, provides the principal entraining cue. In mammals, an endogenous circadian pacemaker located within the suprachiasmatic nucleus (SCN) of the hypothalamus acts as a coordinating centre to align physiological activity with the environmental light-dark cycle. However, the SCN also receives regulatory input from a number of behavioural, non-photic, cues such as physical activity, social interactions and feeding routines. The unique ability of the SCN to integrate both photic and non-photic cues allows it to generate a rhythm that is tailored to the individual and entrained to the environment. Here, we review the key neurotransmitter systems involved in both photic and non-photic transmission to the SCN and their interactions that assist in generating an entrained output rhythm. We also consider the impact on health of a desynchronised circadian system with a focus on depressive affective disorders and current therapies aimed at manipulating the relationship between photic and non-photic SCN regulators.

  8. Vision par ordinateur: outils fondamentaux

    OpenAIRE

    Horaud, Radu; Monga, Olivier

    1995-01-01

    National audience; Cet ouvrage présente les outils fondamentaux de la vision par ordinateur dans un langage mathématique accessible aux étudiants de niveau DEUG en mathématiques ou informatique. Il donne également de nombreux exemples d'utilisation de la vision par ordinateur dans deux domaines de technologie de pointe : la robotique et l'imagerie médicale. Cette deuxième édition largement augmentée est un manuel de référence. Les outils fondamentaux sont présentés dans un langage mathématiqu...

  9. La politique d'éducation au risque de sa réception sur le terrain. Analyse de la mise en oeuvre d'un dispositif d'"année complémentaire" dans trois établissements contrastés

    OpenAIRE

    Draelants, Hugues; Giraldo, Silvia

    2005-01-01

    Draelants, H. & Giraldo, S. (2005). La politique d'éducation au risque de sa réception sur le terrain. Analyse de la mise en oeuvre d'un dispositif d'" année complémentaire " dans trois établissements contrastés. Les Cahiers de Recherche du Girsef, 40.; Ce texte propose une analyse de la réception d'un dispositif de remédiation introduit dans le système scolaire de la Communauté française par décret en 2001. La mise en oeuvre du dispositif est envisagée dans ce cahier au niveau très local de ...

  10. Pseudomyxome péritonéale résultant d'un tératome ovarien associé à une tumeur mucineuse bordeline: à propos d'un cas et revue de la littérature

    Science.gov (United States)

    Mohtaram, Amina; Boutayeb, Saber; El Youbi, Meryam Ben Ameur; Sghiri, Tanae; Aaribi, Imane; Kettani, Fouad; M'rabti, Hind; Errihani, Hassan

    2013-01-01

    Le pseudomyxome péritonéal est défini par la présence de mucine extra-cellulaire dans la cavité péritonéale. Il est dû dans la majorité des cas à la rupture intrapéritonéale d'une tumeur mucineuse d'origine appendiculaire avec extension secondaire ovarienne. Nous rapportons le cas d'une patiente opérée pour tumeur ovarienne droite et dont l’étude histologique était en faveur d'un pseudomyxome péritonéal sur tératome ovarien associé à une tumeur mucineuse bordeline. PMID:23785561

  11. Reaction kinetics of solid fuels during entrained flow gasification

    Energy Technology Data Exchange (ETDEWEB)

    Tremel, Alexander

    2012-10-24

    Despite the application of entrained flow gasification on larger scales, the reaction rates in the hot conversion zone are almost unknown. But the knowledge of the rates of the gasification reactions at high temperature and high pressure is crucial for the detailed design and optimisation of these gasifiers. This dissertation provides measurements of fuel conversion under operation conditions relevant to industrial gasifiers and aims at the transfer of the data to larger scale applications. A novel pilot-scale research reactor is developed that enables the study of gasification reactions at high temperature, high pressure and under entrained flow conditions. The Pressurised High Temperature Entrained Flow Reactor (PiTER) is operated at up to 1600 C and 4.0 MPa in pyrolysis and gasification experiments. The data set is extended by measurements in an atmospheric entrained flow reactor and a pressurised wire mesh reactor. Devolatilisation and gasification behaviour of a wide range of fuels is analysed including anthracite, bituminous coal, lignite, biocoal (from hydrothermal carbonisation), and biomass; however, Rhenish lignite is used in most of the experiments. The pyrolysis data enable the validation of a simple first order reaction model that describes the influence of pressure, temperature, and residence time on volatile yield. Char samples collected from the three reactors are analysed using laboratory procedures and bench-scale setups. Specific char surface area is measured by CO{sub 2} adsorption at 273 K, and is found to be significantly influenced by char conversion, reaction temperature, and devolatilisation pressure. The surface data are described by an extension of the Random Pore Model. Intrinsic char reactivity is measured in a pressurised thermogravimetric analyser and the influence of reactant partial pressure and temperature on the char-CO{sub 2} and char-H{sub 2}O reaction is studied. The intrinsic reaction rate is described by nth order and

  12. ParSplice, Version 1

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-05

    The ParSplice code implements the Parallel Trajectory Splicing algorithm described in [1]. This method is part of the Accelerated Molecular Dynamics family of techniques developed in Los Alamos National Laboratory over the last 16 years. These methods aim at generating high-quality trajectories of ensembles of atoms in materials. ParSplice uses multiple independent replicas of the system in order to parallelize the generation of such trajectories in the time domain, enabling simulations of systems of modest size over very long timescales. ParSplice includes capabilities to store configurations of the system, to generate and distribute tasks across a large number of processors, and to harvest the results of these tasks to generate long trajectories. ParSplice is a management layer that orchestrate large number of calculations, but it does not perform the actual molecular dynamics itself; this is done by external molecular dynamics engines. [1] Danny Perez, Ekin D Cubuk, Amos Waterland, Efthimios Kaxiras, Arthur F Voter, Long-time dynamics through parallel trajectory splicing, Journal of chemical theory and computation 12, 18 (2015)

  13. Audience entrainment during live contemporary dance performance: physiological and cognitive measures.

    Science.gov (United States)

    Bachrach, Asaf; Fontbonne, Yann; Joufflineau, Coline; Ulloa, José Luis

    2015-01-01

    Perceiving and synchronizing to a piece of dance is a remarkable skill in humans. Research in this area is very recent and has been focused mainly on entrainment produced by regular rhythms. Here, we investigated entrainment effects on spectators perceiving a non-rhythmic and extremely slow performance issued from contemporary dance. More specifically, we studied the relationship between subjective experience and entrainment produced by perceiving this type of performance. We defined two types of entrainment. Physiological entrainment corresponded to cardiovascular and respiratory coordinated activities. Cognitive entrainment was evaluated through cognitive tasks that quantified time distortion. These effects were thought to reflect attunement of a participant' internal temporal clock to the particularly slow pace of the danced movement. Each participant' subjective experience-in the form of responses to questionnaires-were collected and correlated with cognitive and physiological entrainment. We observe: (a) a positive relationship between psychological entrainment and attention to breathing (their own one or that of dancers); and (b) a positive relationship between cognitive entrainment (reflected as an under-estimation of time following the performance) and attention to their own breathing, and attention to the muscles' dancers. Overall, our results suggest a close relationship between attention to breathing and entrainment. This proof-of-concept pilot study was intended to prove the feasibility of a quantitative situated paradigm. This research is inscribed in a large-scale interdisciplinary project of dance spectating (labodanse.org).

  14. Audience entrainment during live contemporary dance performance: Physiological and cognitive measures

    Directory of Open Access Journals (Sweden)

    Asaf eBachrach

    2015-05-01

    Full Text Available Perceiving and synchronizing to a piece of dance is a remarkable skill in humans. Research in this area is very recent and has been focused mainly on entrainment produced by regular rhythms. Here, we investigated entrainment effects on spectators perceiving a non-rhythmic and extremely slow performance issued from contemporary dance. More specifically, we studied the relationship between subjective experience and entrainment produced by perceiving this type of performance. We defined two types of entrainment. Physiological entrainment corresponded to cardiovascular and respiratory coordinated activities. Cognitive entrainment was evaluated through cognitive tasks that quantified time distortion. These effects were thought to reflect attunement of a participant' internal temporal clock to the particularly slow pace of the danced movement. Each participant' subjective experience – in the form of responses to questionnaires – were collected and correlated with cognitive and physiological entrainment. We observe: a a positive relationship between psychological entrainment and attention to breathing (their own one or that of dancers; b a positive relationship between cognitive entrainment (reflected as an under-estimation of time following the performance and attention to their own breathing, and attention to the muscles’ dancers. Overall, our results suggest a close relationship between attention to breathing and entrainment. This proof-of-concept pilot study was intended to prove the feasibility of a quantitative situated paradigm. This research is inscribed in a large-scale interdisciplinary project of dance spectating (labodanse.org.

  15. Audience entrainment during live contemporary dance performance: physiological and cognitive measures

    Science.gov (United States)

    Bachrach, Asaf; Fontbonne, Yann; Joufflineau, Coline; Ulloa, José Luis

    2015-01-01

    Perceiving and synchronizing to a piece of dance is a remarkable skill in humans. Research in this area is very recent and has been focused mainly on entrainment produced by regular rhythms. Here, we investigated entrainment effects on spectators perceiving a non-rhythmic and extremely slow performance issued from contemporary dance. More specifically, we studied the relationship between subjective experience and entrainment produced by perceiving this type of performance. We defined two types of entrainment. Physiological entrainment corresponded to cardiovascular and respiratory coordinated activities. Cognitive entrainment was evaluated through cognitive tasks that quantified time distortion. These effects were thought to reflect attunement of a participant’ internal temporal clock to the particularly slow pace of the danced movement. Each participant’ subjective experience—in the form of responses to questionnaires—were collected and correlated with cognitive and physiological entrainment. We observe: (a) a positive relationship between psychological entrainment and attention to breathing (their own one or that of dancers); and (b) a positive relationship between cognitive entrainment (reflected as an under-estimation of time following the performance) and attention to their own breathing, and attention to the muscles’ dancers. Overall, our results suggest a close relationship between attention to breathing and entrainment. This proof-of-concept pilot study was intended to prove the feasibility of a quantitative situated paradigm. This research is inscribed in a large-scale interdisciplinary project of dance spectating (labodanse.org). PMID:25999831

  16. Doing Duo - a case study of entrainment in William Forsythe's choreography "Duo".

    Science.gov (United States)

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe's choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models.

  17. Doing Duo – a Case Study of Entrainment in William Forsythe’s Choreography Duo

    Directory of Open Access Journals (Sweden)

    Elizabeth eWaterhouse

    2014-10-01

    Full Text Available Entrainment theory focuses on processes in which interacting (i.e. coupled rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe's choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and a propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all to examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment as a potential aspect to be incorporated into other models.

  18. Calidad de vida relacionada con la salud de los niños con parálisis cerebral infantil: grado de acuerdo entre hijos y padres

    OpenAIRE

    2016-01-01

    La qualitat de vida relacionada amb la salut (QVRS) en els nens amb paràlisi cerebral infantil (PCI) es pot veure afectada i les percepcions entre els nens i els seus pares poden variar. Els objectius generals d'aquest estudi han estat dos. El primer, mesurar la QVRS dels nens amb PCI i comparar-la amb la d'un grup control format per nens sense cap discapacitat. El segon, determinar el grau d'acord entre fills i pares. Com a objectius específics, es pretenen observar les diferències entre les...

  19. L'effet Peltier appliqué à la conception et la réalisation d'un nouveau capteur de débit massique

    Science.gov (United States)

    Wattiau, F.; Gaviot, E.; Thery, P.

    1993-08-01

    éalisation d'un nouveau capteur de débit massique basé sur l'effet Peltier. Le capteur en forme de circuit imprimé bimétallique, comporte plusieurs pistes métalliques continues parallèles entre elles et partiellement recouvertes par un grand nombre de dépôts électrolytiques de nature différente. Un tel circuit se comporte comme un circuit thermoélectrique classique dans lequel les parties homogènes non recouvertes par le dépôt électrolytique constituent le premier conducteur du couple, les parties plaquées constituant le second conducteur. La méthode de mesure consiste à faire passer un courant électrique dans une ou plusieurs pistes constituant le circuit émetteur de façon à générer par effet Peltier des gradients thermiques qui seront détectés par un circuit détecteur identique placé à proximité. Dans le cas particulier d'un fluide au repos, la f.e.m. détectée par le circuit détecteur dépend de la conductivité thermique du fluide. Lorsque le fluide est en mouvement relatif par rapport au circuit, il est possible de détecter une f.e.m. dépendant en grandeur et en signe de la vitesse d'écoulement du fluide. A titre d'application un capteur de débit massique a été réalisé en plaçant les circuits thermoélectriques dans une canalisation parcourue par le fluide en mouvement.

  20. Melæna massif révélant un syndrome de Peutz-Jeghers vu au CHU-JRA Madagascar: à propos d'un cas

    Science.gov (United States)

    Martinetti, Andrianimaro Florelia; Andriantsoa, Rasoanaivo Mamy; Andriambelo, Rajaonera Tovohery; Nicole, Rakotoarison Ratsaraharimanana Cathérine; Enintsoa, Raveloson Nasolotsiry

    2016-01-01

    Le syndrome de Peutz-Jeghers (SPJ) est caractérisé par l'association d'une polypose digestive hamartomateuse et d'une lentiginose cutanéo-muqueuse. Les malades sont exposés à des complications mécaniques et hémorragiques. Il s'agit d'un syndrome de prédisposition au cancer. Notre étude a pour objectif de rappeler les diagnostiques d'un syndrome de Peutz-Jeghers, de connaitre les complications ainsi que les progrès thérapeutiques dans la prise en charge. Nous avons rapporté le cas d'un homme de 32 ans présentant un melaena massif. Il a été hospitalisé en service de réanimation chirurgicale pour état de choc hypovolémique difficile à contrôler. Il a nécessité une intervention chirurgicale pour arrêter l'hémorragie. Nous avons trouvé un polype hamartomateux dans le grêle qui a causé le saignement. Le diagnostic d'un Syndrome de Peutz-Jeghers a été posé devant la notion de lentiginose labiale pendant l'enfance. Lors de l'exploration clinique et paraclinique, il ne présente pas encore de cancer. A Madagascar, cette pathologie est encore mal connue. Dans la littérature, le syndrome de Peutz-Jeghers peut être révélé cliniquement ou au stade de complication comme l'hémorragie, l'invagination ou l'occlusion intestinale. Dans notre cas, la maladie est compliquée d'une hémorragie digestive avec état de choc hypovolémique. La polypectomie endoscopique par entéroscopie à double ballonnet permet de diminuer le recours à la chirurgie grêlique d'urgence. Le syndrome de Peutz-Jeghers est une affection rare. Mais il est important aux cliniciens de le connaitre et de penser à sa possibilité en cas d'hémorragie digestive. PMID:27217901

  1. Mixing and entrainment in hydraulically driven stratified sill flows

    Science.gov (United States)

    Holtegaard Nielsen, Morten; Pratt, Larry; Helfrich, Karl

    2004-09-01

    The investigation involves the hydraulic behaviour of a dense layer of fluid flowing over an obstacle and subject to entrainment of mass and momentum from a dynamically inactive (but possibly moving) overlying fluid. An approach based on the use of reduced gravity, shallow-water theory with a cross-interface entrainment velocity is compared with numerical simulations based on a model with continuously varying stratification and velocity. The locations of critical flow (hydraulic control) in the continuous model are estimated by observing the direction of propagation of small-amplitude long-wave disturbances introduced into the flow field. Although some of the trends predicted by the shallow-water model are observed in the continuous model, the agreement between the interface profiles and the position of critical flow is quantitatively poor. A reformulation of the equations governing the continuous flow suggests that the reduced gravity model systematically underestimates inertia and overestimates buoyancy. These differences are quantified by shape coefficients that measure the vertical non-uniformities of the density and horizontal velocity that arise, in part, by incomplete mixing of entrained mass and momentum over the lower-layer depth. Under conditions of self-similarity (as in Wood's similarity solution) the shape coefficients are constant and the formulation determines a new criterion for and location of critical flow. This location generally lies upstream of the critical section predicted by the reduced-gravity model. Self-similarity is not observed in the numerically generated flow, but the observed critical section continues to lie upstream of the location predicted by the reduced gravity model. The factors influencing this result are explored.

  2. L'ethique de l'environnement comme dimension transversale de l'education en sciences et en technologies: Proposition d'un modele educationnel

    Science.gov (United States)

    Chavez, Milagros

    Cette these presente la trajectoire et les resultats d'une recherche dont l'objectif global est de developper un modele educationnel integrant l'ethique de l'environnement comme dimension transversale de l'education en sciences et en technologies. Face au paradigme positiviste toujours dominant dans l'enseignement des sciences, il a semble utile d'ouvrir un espace de reflexion et de proposer, sous forme d'un modele formel, une orientation pedagogique qui soit plus en resonance avec quelques-unes des preoccupations fondamentales de notre epoque: en particulier celle qui concerne la relation de humain avec son environnement et plus specifiquement, le role de la science dans le faconnement d'une telle relation, par sa contribution a la transformation des conditions de vie, au point de compromettre les equilibres naturels. En fonction de cette problematique generale, les objectifs de la recherche sont les suivants: (1) definir les elements paradigmatiques, theoriques et axiologiques du modele educationnel a construire et (2) definir ses composantes strategiques. De caractere theorico-speculatif, cette recherche a adopte la demarche de l'anasynthese, en la situant dans la perspective critique de la recherche en education. Le cadre theorique de cette these s'est construit autour de quatre concepts pivots: modele educationnel, education en sciences et en technologies, transversalite educative et ethique de l'environnement. Ces concepts ont ete clarifies a partir d'un corpus textuel, puis, sur cette base, des choix theoriques ont ete faits, a partir desquels un prototype du modele a ete elabore. Ce prototype a ensuite ete soumis a une double validation (par des experts et par une mise a l'essai), dans le but d'y apporter des ameliorations et, a partir de la, de construire un modele optimal. Ce dernier comporte deux dimensions: theorico-axiologique et strategique. La premiere s'appuie sur une conception de l'education en sciences et en technologies comme appropriation d'un

  3. A Heart for Interaction: Physiological Entrainment and Behavioral Coordination in a Collective, Creative Construction Task

    CERN Document Server

    Fusaroli, Riccardo; Roepstoff, Andreas; Tylén, Kristian

    2015-01-01

    Interpersonal physiological entrainment is increasingly argued to underlie rapport, empathy and even team performance. Inspired by the model of interpersonal synergy, we investigate the presence, temporal development, possible mechanisms and impact of interpersonal heart rate entrainment during individual and collective creative LEGO construction tasks. In Study 1 we show how HR entrainment is driven by a plurality of sources including task constraints and behavioral coordination. Generally, HR entrainment is more prevalent in individual trials (involving participants doing the same things) than in collective ones (involving participants taking turns and performing complementary actions). However, when contrasted against virtual pairs, collective trials display more stable HR entrainment supporting the idea that online social interaction plays a role. Furthermore, HR entrainment is found to grow across collective but not individual trials. In Study 2 we further show that in collective trials the dynamics of H...

  4. Complex Patterns of Metabolic and Ca2+ Entrainment in Pancreatic Islets by Oscillatory Glucose

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram; Mosekilde, Erik; Polonsky, Kenneth S.

    2013-01-01

    fluorescence microscopy to demonstrate that glucose oscillations can induce distinct 1:1 and 1:2 entrainment of oscillations (one and two oscillations for each period of exogenous stimulus, respectively) in islet Ca2+ , NAD(P)H, and mitochondrial membrane potential. To our knowledge, this is the first......Glucose-stimulated insulin secretion is pulsatile and driven by intrinsic oscillations in metabolism, electrical activity, and Ca2+in pancreatic islets. Periodic variations in glucose can entrain islet Ca2+ and insulin secretion, possibly promoting interislet synchronization. Here, we used...... demonstration of metabolic entrainment in islets, and we found that entrainment of metabolic oscillations requires voltage-gated Ca2+ influx. We identified diverse patterns of 1:2 entrainment and showed that islet synchronization during entrainment involves adjustments of both oscillatory phase and period. All...

  5. Effects of continuous chlorination on entrained estuarine plankton

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, S.J.; Foulk, H.R.

    1980-01-01

    Technical report: The effects of continuous chlorination in running sea water on entrained plankton were examined. The concentration of ATP was used as an indicator of biomass because: it is present in all living cells; the concentration is proportional to the living biomass; and dead cells lose ATP rapidly. Effects were measured by bioluminescence; luciferin-luciferase reagents from firefly lanterns were used to analyze ATP concentration. Results indicate that ATP measurement is an accurate, effective means of evaluating damage done to planktonic organisms by continuous chlorination. Further studies of the effects of low-concentration, continuous chlorination are recommended. (13 references, 1 table)

  6. Entrained Flow Reactor Test of Potassium Capture by Kaolin

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2015-01-01

    In the present study a method to simulate the reaction between gaseous KCl and kaolin at suspension fired condition was developed using a pilot-scale entrained flow reactor (EFR). Kaolin was injected into the EFR for primary test of this method. By adding kaolin, KCl can effectively be captured......, forming water-insoluble K-aluminosilicate. The amount of K captured by 1 g kaolin rose when increasing the molar ratio of K/Si in the reactant. Changing of reaction temperature from 1100 °C to 1300 °C did not influence the extent of reaction, which is different from the results observed in previous fixed...

  7. The effects of chronic marijuana use on circadian entrainment.

    Science.gov (United States)

    Whitehurst, Lauren N; Fogler, Kethera; Hall, Kate; Hartmann, Matthew; Dyche, Jeff

    2015-05-01

    Animal literature suggests a connection between marijuana use and altered circadian rhythms. However, the effect has not yet been demonstrated in humans. The present study examined the effect of chronic marijuana use on human circadian function. Participants consisted of current users who reported smoking marijuana daily for at least a year and non-marijuana user controls. Participants took a neurocognitive assessment, wore actigraphs and maintained sleep diaries for three weeks. While no significant cognitive changes were found between groups, data revealed that chronic marijuana use may act as an additional zeitgeber and lead to increased entrainment in human users.

  8. Turbulence and entrainment length scales in large wind farms

    DEFF Research Database (Denmark)

    Andersen, Søren Juhl; Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming

    2017-01-01

    be taken into account when developing farm layouts. The self-organized motion or large coherent structures also yield high correlations between the power productions of consecutive turbines, which can be exploited through dynamic farm control.This article is part of the themed issue 'Wind energy in complex...... orthogonal decomposition, which is employed to detect the largest and most energetic coherent turbulent structures. The dominant length scales responsible for the entrainment process are shown to grow further into the wind farm, but to be limited in extent by the streamwise turbine spacing, which could...

  9. Par Pond Fish, Water, and Sediment Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

  10. A viscoplastic lubrication model for entrainment by avalanches and debris flows, and comparison with experiments

    Science.gov (United States)

    Bates, Belinda; Ancey, Christophe

    2015-04-01

    Recently, experiments were designed and carried out examining how a viscoplastic avalanche begins to entrain a shallow layer of identical fluid lying in its path, much like a snow avalanche or mud flow which suddenly encounters an entrainable layer, described as a yield stress material. This represents a simplified problem, investigated in order to gain some physical insight into entrainment by avalanches. These experiments serve as a test for mathematical models of entraining gravity currents. Two classes of entrainment behaviour were observed: either the avalanche ``glided'' out over the entrainable bed, immediately shearing it in the downstream direction and progressively incorporating fluid down to the rigid base, or the avalanche seemed to ``roll'' out onto the entrainable bed, with strong motion in the slope-normal direction in the bed after yield. This difference in behaviour was dictated by the magnitude of the flume's slope. For the steeper flows studied (20 and 24 degrees), entrainment was principally in the former class, whereas for shallower slope angle (12 and 16 degrees) entrainment more closely resembled the latter type. This would suggest that there is a competition between the normal and shear stresses exerted on the bed, with bed-yield and entrainment occurring when these stresses exceed a critical value. An interesting phenomenon that was observed in all cases was a sort of buckling of the bed, downstream of the avalanche front. This was far more significant in the flows down shallower slopes, and regular waves were created in the bed with wavelength dependent on the flow depth. Based on theoretical comparisons with non-entraining Herschel Bulkley flows, the physics of entraining flows are investigated numerically for shallow viscoplastic gravity currents on different slopes. The predictions are compared with the experimental values for velocity field and surface height. The model was successful in reproducing velocities of the correct order, but

  11. Separation of Erucic Acid from Rape-Seed Oil Using Supercritical Carbon Dioxide with Entrainer

    Institute of Scientific and Technical Information of China (English)

    云志; 钱仁渊; 等

    2002-01-01

    Separation of erucic acid from rape-seed oil using supercritical carbon dioxide with entrainer was carried on a pilot column with an inner diameter 14 mm and an effective total height 2.2m.Experiments were focused on the effects of entrainers.i.e.acetone.ethanol and ethyl acetate,on the extraction.It is showed that entrainers made selectivity lower,but separation time shorter.

  12. [Effect of entrainer on supercritical CO2 for extraction of tradition and herbal drugs].

    Science.gov (United States)

    Xi, Yanbin; Xia, Xiaohui; Jin, Ran; Zhang, Yu; Yang, Liqin; Tang, Shihuan

    2009-06-01

    Type, mode of affiliating, mechanism of action of entrainer in Supercritical CO2 on extraction of Chinese traditional and herbal drugs were briefly reviewed. Application of entrainer in Supercritical CO2 on extraction of flavones, terpenes, sterols, and saponins in Chinese traditional and herbal drugs were recommended in particular. Some problems and directions in research of entrainer in Supercritical CO2 on extraction of Chinese traditional and herbal drugs were shown in this paper.

  13. The performative pleasure of imprecision: a diachronic study of entrainment in music performance

    OpenAIRE

    Andrew eGeeves; Doris Jane McIlwain; John eSutton

    2014-01-01

    This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and sm...

  14. Doing Duo – a Case Study of Entrainment in William Forsythe’s Choreography Duo

    OpenAIRE

    Elizabeth eWaterhouse; Riley eWatts; Bläsing, Bettina E.

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e. coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress...

  15. Auditory-motor entrainment in vocal mimicking species: Additional ontogenetic and phylogenetic factors

    OpenAIRE

    Schachner, Adena

    2010-01-01

    We have recently found robust evidence of motor entrainment to auditory stimuli in multiple species of non-human animal, all of which were capable of vocal mimicry. In contrast, the ability remained markedly absent in many closely related species incapable of vocal mimicry. This suggests that vocal mimicry may be a necessary precondition for entrainment. However, within the vocal mimicking species, entrainment appeared non-randomly, suggesting that other components besides vocal mimicry play ...

  16. Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume I. Entrainment-impact estimates for six fish populations inhabiting the Hudson River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Boreman, J.; Barnthouse, L.W.; Vaughn, D.S.; Goodyear, C.P.; Christensen, S.W.; Kumar, K.D.; Kirk, B.L.; Van Winkle, W.

    1982-01-01

    This volume is concerned with the estimation of the direct (or annual) entrainment impact of power plants on populations of striped bass, white perch, Alosa spp. (blueback herring and alewife), American shad, Atlantic tomcod, and bay anchovy in the Hudson River estuary. Entrainment impact results from the killing of fish eggs, larvae, and young juveniles that are contained in the cooling water cycled through a power plant. An Empirical Transport Model (ETM) is presented as the means of estimating a conditional entrainment mortality rate (defined as the fraction of a year class which would be killed due to entrainment in the absence of any other source of mortality). Most of this volume is concerned with the estimation of several parameters required by the ETM: physical input parameters (e.g., power-plant withdrawal flow rates); the longitudinal distribution of ichthyoplankton in time and space; the duration of susceptibility of the vulnerable organisms; the W-factors, which express the ratios of densities of organisms in power plant intakes to densities of organisms in the river; and the entrainment mortality factors (f-factors), which express the probability that an organism will be killed if it is entrained. Once these values are obtained, the ETM is used to estimate entrainment impact for both historical and projected conditions.

  17. Phenomenologie D'un Boson Neutre z' Arbitraire

    Science.gov (United States)

    Turcotte, Paul

    Les bosons neutres Z' apparaissent dans un grand nombre de modeles d'unification des forces mais aucune mesure n'a revele son existence. Le but de cette these est de tester avec un modele phenomenologique les limites sur les parametres d'un boson Z' premier temps evaluer avec precision les predictions avec les bosons neutres existants et ensuite ajouter la nouvelle contribution. A cette occasion, les formules detailees des predictions de ces courants neutres et de leurs corrections radiatives du modele standard seront donnees. Apres avoir rassemble toutes les donnees importantes sur les courants neutres, cette analyse donne en fonction de la masse du Z' des limites sur tous ses couplages et sur l'angle de melange avec le boson Z^0. Ensuite les correlations entre les differents couplages sont montrees pour m _{Z'} = 200 GeV/c^2. Les plus faibles limites sont obtenues lorsque le boson Z' se couple uniquement aux leptons ou aux quarks. La these se termine en montrant que les experiences futures pourront grandement ameliorer les contraintes. En effet, des limites sur les couplages pourront exister pour une masse du Z' de quelques TeV/ c^2.

  18. Controlling entrainment in the smoke cloud using level set-based front tracking

    Directory of Open Access Journals (Sweden)

    Eckhard Dietze

    2015-01-01

    Full Text Available Although large-eddy simulation (LES has been shown to produce a reasonable representation of the turbulent circulations within the stratocumulus-topped boundary layer, it has difficulties to accurately predict cloud-top entrainment rates. In this paper, we present a front-tracking algorithm for LES to untangle the numerical and physical contributions to entrainment. Instead of resolving the cloud-top inversion, we treat it as a discontinuity separating the boundary layer from the free atmosphere and use the level set method to track its location. We apply our method to the smoke cloud test case as presented by Bretherton et al. (1999 which is simpler than stratocumulus in that it is only driven by radiative cooling avoiding evaporative feedbacks on entrainment. We present three-dimensional LES results with and without use of the level set method varying the grid resolution and the flux limiter. With the level set method, we prescribe zero entrainment and use this case to evaluate our method's ability to maintain a non-entraining smoke-cloud layer. We use an empirically-based entrainment law to estimate numerical errors. With the level set method, the prescribed entrainment rate was maintained with errors about one order of magnitude smaller than the entrainment errors found in the standard LES. At the same time, the dependence of the entrainment errors on the choice of the limiter was reduced by more than a factor of 10.

  19. Identified proprioceptive afferents and motor rhythm entrainment in the crayfish walking system.

    Science.gov (United States)

    Elson, R C; Sillar, K T; Bush, B M

    1992-03-01

    1. In crayfish, Pacifastacus leniusculus, remotion of a walking leg stretches the thoraco-coxal (TC) muscle receptor organ (TCMRO), located at the leg's articulation with the thorax. In vitro, alternate stretch and release of the fourth leg's TCMRO entrained the centrally generated rhythmic motor output to that leg, with the remotor phase of the rhythm entraining to TCMRO stretch, the promoter phase to release. This coordination of motor bursts to afferent input corresponds to that of active, rhythmic movements in vivo. 2. Entrainment was rapid in onset (stable coordination resulting within the first or second stimulus cycle) and was relatively phase-constant (whatever the stimulus frequency, during 1:1 entrainment, remotor bursts began near the onset of stretch and promotor bursts began near the onset of release). Outside the range of 1:1 entrainment, 2:1, 1:2, and 1:3 coordination ratios (rhythm:stimulus) were encountered. Resetting by phasic stimulation of the TCMRO was complete and probabilistic: effective stimuli triggered rapid transitions between the two burst phases. 3. The TCMRO is innervated by two afferents, the nonspiking S and T fibers, which generate graded depolarizing receptor potentials in response to stretch. During proprioceptive entrainment, the more phasic T fiber depolarized and hyperpolarized more rapidly or in advance of the more tonic S fiber. These receptor potentials were modified differently in the two afferents by interaction with central synaptic inputs that were phase-locked to the entrained motor rhythm. 4. Injecting slow sinusoidal current into either afferent alone could entrain motor rhythms: promoter phase bursts were entrained to depolarization of the S fiber or hyperpolarization of the T fiber, whereas the converse response was obtained for remotor phase bursts. 5. During proprioceptive entrainment, tonic hyperpolarization of the S fiber weakened entrained promotor bursts and allowed remotor burst durations to increase

  20. Sensory entrainment mechanisms in auditory perception: neural synchronization and cortico-striatal activation

    Directory of Open Access Journals (Sweden)

    Catia M Sameiro-Barbosa

    2016-08-01

    Full Text Available The auditory system displays modulations in sensitivity that can align with the temporal structure of the acoustic environment. This sensory entrainment can facilitate sensory perception and is particularly relevant for audition. Systems neuroscience is slowly uncovering the neural mechanisms underlying the behaviorally observed sensory entrainment effects in the human sensory system. The present article summarizes the prominent behavioral effects of sensory entrainment and reviews our current understanding of the neural basis of sensory entrainment, such as synchronized neural oscillations and, potentially, neural activation in the cortico-striatal system.

  1. Auditory cortical delta-entrainment interacts with oscillatory power in multiple fronto-parietal networks.

    Science.gov (United States)

    Keitel, Anne; Ince, Robin A A; Gross, Joachim; Kayser, Christoph

    2017-02-15

    The timing of slow auditory cortical activity aligns to the rhythmic fluctuations in speech. This entrainment is considered to be a marker of the prosodic and syllabic encoding of speech, and has been shown to correlate with intelligibility. Yet, whether and how auditory cortical entrainment is influenced by the activity in other speech-relevant areas remains unknown. Using source-localized MEG data, we quantified the dependency of auditory entrainment on the state of oscillatory activity in fronto-parietal regions. We found that delta band entrainment interacted with the oscillatory activity in three distinct networks. First, entrainment in the left anterior superior temporal gyrus (STG) was modulated by beta power in orbitofrontal areas, possibly reflecting predictive top-down modulations of auditory encoding. Second, entrainment in the left Heschl's Gyrus and anterior STG was dependent on alpha power in central areas, in line with the importance of motor structures for phonological analysis. And third, entrainment in the right posterior STG modulated theta power in parietal areas, consistent with the engagement of semantic memory. These results illustrate the topographical network interactions of auditory delta entrainment and reveal distinct cross-frequency mechanisms by which entrainment can interact with different cognitive processes underlying speech perception.

  2. Axially symmetric equations for differential pulsar rotation with superfluid entrainment

    Science.gov (United States)

    Antonelli, M.; Pizzochero, P. M.

    2017-01-01

    In this article we present an analytical two-component model for pulsar rotational dynamics. Under the assumption of axial symmetry, implemented by a paraxial array of straight vortices that thread the entire neutron superfluid, we are able to project exactly the 3D hydrodynamical problem to a 1D cylindrical one. In the presence of density-dependent entrainment the superfluid rotation is non-columnar: we circumvent this by using an auxiliary dynamical variable directly related to the areal density of vortices. The main result is a system of differential equations that take consistently into account the stratified spherical structure of the star, the dynamical effects of non-uniform entrainment, the differential rotation of the superfluid component and its coupling to the normal crust. These equations represent a mathematical framework in which to test quantitatively the macroscopic consequences of the presence of a stable vortex array, a working hypothesis widely used in glitch models. Even without solving the equations explicitly, we are able to draw some general quantitative conclusions; in particular, we show that the reservoir of angular momentum (corresponding to recent values of the pinning forces) is enough to reproduce the largest glitch observed in the Vela pulsar, provided its mass is not too large.

  3. Hydrodynamics of air entrainment by moving contact lines

    CERN Document Server

    Chan, T S; Marchand, A; Andreotti, B; Biferale, L; Toschi, F; Snoeijer, J H

    2013-01-01

    We study the dynamics of the interface between two immiscible fluids in contact with a chemically homogeneous moving solid plate. We consider the generic case of two fluids with any viscosity ratio and of a plate moving in either directions (pulled or pushed in the bath). The problem is studied by a combination of two models, namely an extension to finite viscosity ratio of the lubrication theory and a Lattice Boltzmann method. Both methods allow to resolve, in different ways, the viscous singularity at the triple contact between the two fluids and the wall. We find a good agreement between the two models particularly for small capillary numbers. When the solid plate moves fast enough, the entrainment of one fluid into the other one can occur. The extension of the lubrication model to the case of a non-zero air viscosity, as developed here, allows us to study the dependence of the critical capillary number for air entrainment on the other parameters in the problem (contact angle and viscosity ratio).

  4. Hydrodynamics of air entrainment by moving contact lines

    Science.gov (United States)

    Chan, T. S.; Srivastava, S.; Marchand, A.; Andreotti, B.; Biferale, L.; Toschi, F.; Snoeijer, J. H.

    2013-07-01

    We study the dynamics of the interface between two immiscible fluids in contact with a chemically homogeneous moving solid plate. We consider the generic case of two fluids with any viscosity ratio and of a plate moving in either directions (pulled or pushed in the bath). The problem is studied by a combination of two models, namely, an extension to finite viscosity ratio of the lubrication theory and a Lattice Boltzmann method. Both methods allow to resolve, in different ways, the viscous singularity at the triple contact between the two fluids and the wall. We find a good agreement between the two models particularly for small capillary numbers. When the solid plate moves fast enough, the entrainment of one fluid into the other one can occur. The extension of the lubrication model to the case of a non-zero air viscosity, as developed here, allows us to study the dependence of the critical capillary number for air entrainment on the other parameters in the problem (contact angle and viscosity ratio).

  5. Universal mechanism for air entrainment during liquid impact

    CERN Document Server

    Hendrix, Maurice H W; van der Meer, Devaraj; Lohse, Detlef; Snoeijer, Jacco H

    2015-01-01

    When a mm-sized liquid drop approaches a deep liquid pool, both the interface of the drop and the pool deform before the drop touches the pool. The build up of air pressure prior to coalescence is responsible for this deformation. Due to this deformation, air can be entrained at the bottom of the drop during the impact. We quantify the amount of entrained air numerically, using the Boundary Integral Method (BIM) for potential flow for the drop and the pool, coupled to viscous lubrication theory for the air film that has to be squeezed out during impact. We compare our results to various experimental data and find excellent agreement for the amount of air that is entrapped during impact onto a pool. Next, the impact of a rigid sphere onto a pool is numerically investigated and the air that is entrapped in this case also matches with available experimental data. In both cases of drop and sphere impact onto a pool the numerical air bubble volume V_b is found to be in agreement with the theoretical scaling V_b/V_...

  6. Debris entrainment and landform genesis during tidewater glacier surges

    Science.gov (United States)

    Lovell, Harold; Fleming, Edward J.; Benn, Douglas I.; Hubbard, Bryn; Lukas, Sven; Rea, Brice R.; Noormets, Riko; Flink, Anne E.

    2015-08-01

    The englacial entrainment of basal debris during surges presents an opportunity to investigate processes acting at the glacier bed. The subsequent melt-out of debris-rich englacial structures during the quiescent phase produces geometrical ridge networks on glacier forelands that are diagnostic of surge activity. We investigate the link between debris entrainment and proglacial geomorphology by analyzing basal ice, englacial structures, and ridge networks exposed at the margins of Tunabreen, a tidewater surge-type glacier in Svalbard. The basal ice facies display clear evidence for brittle and ductile tectonic deformation, resulting in overall thickening of the basal ice sequence. The formation of debris-poor dispersed facies ice is the result of strain-induced metamorphism of meteoric ice near the bed. Debris-rich englacial structures display a variety of characteristics and morphologies and are interpreted to represent the incorporation and elevation of subglacial till via the squeezing of till into basal crevasses and hydrofracture exploitation of thrust faults, reoriented crevasse squeezes, and preexisting fractures. These structures are observed to melt-out and form embryonic geometrical ridge networks at the base of a terrestrially grounded ice cliff. Ridge networks are also located at the terrestrial margins of Tunabreen, neighboring Von Postbreen, and in a submarine position within Tempelfjorden. Analysis of network characteristics allows these ridges to be linked to different formational mechanisms of their parent debris-rich englacial structures. This in turn provides an insight into variations in the dominant tectonic stress regimes acting across the glacier during surges.

  7. Regulatory mutations in TBX3 disrupt asymmetric hair pigmentation that underlies Dun camouflage color in horses

    DEFF Research Database (Denmark)

    Imsland, Freyja; McGowan, Kelly; Rubin, Carl-Johan

    2016-01-01

    Dun is a wild-type coat color in horses characterized by pigment dilution with a striking pattern of dark areas termed primitive markings. Here we show that pigment dilution in Dun horses is due to radially asymmetric deposition of pigment in the growing hair caused by localized expression of the...

  8. Tutorat en ligne et création d'un espace formatif E-tutoring: how to design a formative field

    Directory of Open Access Journals (Sweden)

    Jean-François Bourdet

    2007-03-01

    Full Text Available Cette conférence traite de la construction en ligne d'un espace formatif. Nous entendons par là la représentation et la mise en œuvre par les usagers d'un dispositif de formation en ligne, d'une conception de celui-ci permettant d'en saisir et d'en interpréter les buts, d'en dégager les implications en termes d'attitudes d'apprentissage, de modes d'échanges, d'interactions au sens le plus large. Dans cette perspective, le tutorat comme fonction formative se caractérise par l'exercice de rôles variés et parfois contradictoires (empathie paritaire / validation d'étapes, guidage général / adaptation aux spécificités. Une conséquence est alors l'exigence de distribution de ces rôles sur des acteurs différents, tant humains (tutorat statutaire exercé par une enseignant ou paritaire dans un groupe en formation que logiciels (agents de type compagnon voués à des rôles d'alertes et de propositions d'activités contextualisées par exemple. L'hypothèse est qu'un tel partage contribue à valider l'"ouverture" d'une formation et ce d'autant plus qu'il est conçu de manière à pouvoir évoluer au fil des échanges en ligne. On présentera donc les concepts clés de cette problématique : conception et développement des dispositifs, espace de communication, fonctionnalités offertes par les environnements, outils dédiés au tutorat, afin de mettre en évidence la spécificité de telles situations éducatives.The main goal of the paper is to provide an insight concerning a specific field of research in On line learning. Beside teaching devices design (program, tutoring, tools, we have to think on which way users develop a system representation including conception of the tasks, interactions with others users (students, tutors and interpretation of user's actions by him(herself.This paper suggests that an important part of On line learning experience is the building (design of a virtual space of communication where any user implant

  9. suPAR: The Molecular Crystal Ball

    Directory of Open Access Journals (Sweden)

    Maria Thunø

    2009-01-01

    Full Text Available soluble urokinase Plasminogen Activator Receptor (suPAR levels reflect inflammation and elevated suPAR levels are found in several infectious diseases and cancer. suPAR exists in three forms; suPARI-III, suPARII-III and suPARI which show different properties due to structural differences. Studies suggest that full-length suPAR is a regulator of uPAR/uPA by acting as uPA-scavenger, whereas the cleaved suPARII-III act as a chemotactic agent promoting the immune response via the SRSRY sequence in the linker-region. This review focus on the various suPAR fragments and their involvement in inflammation and pathogenic processes. We focus on the molecular mechanisms of the suPAR fragments and the link to the inflammatory process, as this could lead to medical applications in infectious and pathological conditions.

  10. La tuberculose nasosinusienne primaire: à propos d'un cas

    Science.gov (United States)

    Bouchentouf, Rachid; Bouaity, Brahim; Touati, Mohamed; Benjelloun, Amine; Aitbenasser, Moulay Ali

    2013-01-01

    La localisation nasosinusienne de la tuberculose est rare. Elle est caractérisée par une présentation clinique polymorphe et non spécifique, posant souvent un problème de diagnostic différentiel. Le diagnostic repose sur l'examen anatomopathologique et bactériologique avec examen direct et culture. Le traitement est essentiellement médical à base d'antibacillaires. PMID:23503658

  11. Developpement de techniques de diagnostic non intrusif par tomographie optique

    Science.gov (United States)

    Dubot, Fabien

    Que ce soit dans les domaines des procedes industriels ou de l'imagerie medicale, on a assiste ces deux dernieres decennies a un developpement croissant des techniques optiques de diagnostic. L'engouement pour ces methodes repose principalement sur le fait qu'elles sont totalement non invasives, qu'elle utilisent des sources de rayonnement non nocives pour l'homme et l'environnement et qu'elles sont relativement peu couteuses et faciles a mettre en oeuvre comparees aux autres techniques d'imagerie. Une de ces techniques est la Tomographie Optique Diffuse (TOD). Cette methode d'imagerie tridimensionnelle consiste a caracteriser les proprietes radiatives d'un Milieu Semi-Transparent (MST) a partir de mesures optiques dans le proche infrarouge obtenues a l'aide d'un ensemble de sources et detecteurs situes sur la frontiere du domaine sonde. Elle repose notamment sur un modele direct de propagation de la lumiere dans le MST, fournissant les predictions, et un algorithme de minimisation d'une fonction de cout integrant les predictions et les mesures, permettant la reconstruction des parametres d'interet. Dans ce travail, le modele direct est l'approximation diffuse de l'equation de transfert radiatif dans le regime frequentiel tandis que les parametres d'interet sont les distributions spatiales des coefficients d'absorption et de diffusion reduit. Cette these est consacree au developpement d'une methode inverse robuste pour la resolution du probleme de TOD dans le domaine frequentiel. Pour repondre a cet objectif, ce travail est structure en trois parties qui constituent les principaux axes de la these. Premierement, une comparaison des algorithmes de Gauss-Newton amorti et de Broyden- Fletcher-Goldfarb-Shanno (BFGS) est proposee dans le cas bidimensionnel. Deux methodes de regularisation sont combinees pour chacun des deux algorithmes, a savoir la reduction de la dimension de l'espace de controle basee sur le maillage et la regularisation par penalisation de Tikhonov

  12. Lecture assistée par ordinateur en otolithométrie : application à l'étude de l'âge de Lutjanus sebae (Cuvier, 1828) aux Seychelles

    OpenAIRE

    Chauvelon, Philippe

    1990-01-01

    La présente étude porte sur la détermination otolithométrique de l'âge d'un poisson exploité sur le plateau des Seychelles, #Lutjanus sebae$ (Cuvier, 1828). Les observations ont été effectuées sur des coupes transversales d'otolithes sagitta incluses à l'aide d'un dispositif d'analyse d'image. En raison des particularités du matériel biologique étudié, une approche originale du rétrocalcul de la taille des poissons est envisagée. Une partie du plan de coupe est modélisée par une ellipse perme...

  13. Apports de l'Intelligence Economique dans un Système d'Information Stratégique universitaire : innovation par le processus de modélisation des acteurs

    OpenAIRE

    2006-01-01

    Nous abordons une nouvelle gouvernance des universités en empruntant le processus d'intelligence économique pour faire évoluer un système d'information universitaire en un système d'information stratégique universitaire. Le transfert d'un système d'information en système d'information décisionnel repose sur les bases métiers orientées vers les acteurs de l'université par la prise en compte de la modélisation des utilisateurs. Le développement d'un système d'information global de l'université ...

  14. Turbulent entrainment in sediment-laden flows interacting with an obstacle

    Science.gov (United States)

    Wilson, Richard I.; Friedrich, Heide; Stevens, Craig

    2017-03-01

    Temporal entrainment characteristics and mixing processes of sediment-laden turbidity currents interacting with a rectangular obstacle are investigated through lock-exchange experiments. Building on the Morton-Taylor-Turner hypothesis, dependency of temporal entrainment on non-dimensional parameters is examined. Currents of varying density are analyzed during the slumping phase over smooth and rough substrates. Quantitative and qualitative observations of the currents are captured through high resolution, high framerate binary thresholding techniques. Additionally, siphoning techniques are used to compare the density structure of the currents before and after the obstacle. Upon interaction with the obstacle, currents are found to experience four stages of entrainment: (i) lateral entrainment stage; (ii) jet stage; (iii) collapsing stage; (iv) re-establishment stage. The entrainment parameter was within the range of other studies for both obstacle and no-obstacle cases. Reynolds, Froude, and Richardson numbers are also comparable to previous studies; however, there was no clear relationship with the entrainment parameter. This suggests that entrainment dependency on non-dimensional parameters is not quantifiable where the analysis area length to lock-box length ratio is ≈1. The presence of the obstacle was shown to increase entrainment by approximately 99% immediately downstream of the obstacle, associated with a subsequent entrainment decrease by 14% at the downstream end of the analysis area. For rectangular obstacles 1/6th the initial current height, as used for this study, an obstacle's role is limited in decreasing net velocity and entrainment and not fit-for-purpose as a barrier to reduce current velocity. Finally, we discuss optimization strategies, weighing up observed minimal net velocity/entrainment decrease with the detrimental effects of jet expansion.

  15. Effect of the Entrained Air Void on Strength and Interfacial Transition Zone of Air-Entrained Mortar

    Institute of Scientific and Technical Information of China (English)

    GAO Hui; ZHANG Xiong; ZHANG Yongjuan

    2015-01-01

    In order to facilitate the development and application of air entraining agents (AEA) in the high performance concrete, entrained air void structure parameters (air void size range from 10 to 1 600 μm) of 28 d sifted mortar were measured by image analysis method. The relationship between the air void size distribution and strength of mortar was studied by methods of grey connection analysis and multiple linear regression analysis. The multiple linear regression equation was established with a correlation coefifcient of 0.966. The weight of the affection of hierarchical porosity on the compressive strength ratio was also obtained. In addition, the effect of air voids on the paste-aggregate interfacial transition zone (ITZ) was analyzed by microhardness. The results show that the correlation between different pore size range and the compressive strength is negative. The effect of air void size distribution on 28 days compressive strength is different: under the condition of similar total porosity, with the increase of the porosity of the air void size, ranging from 10 to 200 μm, and the decrease of the porosity, ranging from 200 to 1 600 μm, the average air void diameter and mean free spacing are decreased; as well as the width of ITZ. On the contrary, the microhardness of the ITZ is increased while the compressive strength loss is decreased.

  16. LES ENJEUX DE LA CREATIVITE INTER-ORGANISATIONNELLE A L'ECHELLE LOCALE. LE CAS DU CONCOURS DESIGN CONCEPT INITIE PAR LE TERRITOIRE DE LA LOIRE (FRANCE)

    OpenAIRE

    Dechamp, Gaelle; Szostak, Berangere

    2012-01-01

    International audience; Comment et par qui la créativité collaborative entre PME est-elle gérée? Quels sont les effets du territoire local sur la créativité inter-organisationnelle? Les différents niveaux créatifs d'un territoire, identifiés par les chercheurs en économie créative, peuvent-ils se mailler pour favoriser la créativité inter-organisationnelle ? Le but de cette recherche qualitative est de répondre à ces questions, en palliant des manques et malentendus dans la littérature. En ef...

  17. 24. Entrainment of wide complex tachycardia by atrial stimulation is highly accurate and can rapidly elucidate the tachycardia mechanism through analysis of entrainment response

    Directory of Open Access Journals (Sweden)

    Abdulhakim Noman

    2015-10-01

    Conclusion: Response to atrial entrainment can be helpful in the majority of WCT patients, particularly those with 1:1 AV relationship to diagnose or rule out VT as a mechanism of tachycardia with high accuracy.

  18. Haecceitas and the Question of Being: Heidegger and Duns Scotus

    Directory of Open Access Journals (Sweden)

    Philip Tonner

    2008-12-01

    Full Text Available Over the thirty years since his death Martin Heidegger (1889-1976 hasemerged as one of the key philosophers of the 20th Century. Yet he claimed to be moved throughout the entirety of his work by a single question: the question of the meaning of being. According to Heidegger the ancient Greek thinkers experienced being with a sense of wonder that has been lost in modernity. There has never been a satisfactory answer to this question and philosophers are no longer even perplexed by their inability to answer it. It was the question of being (Seinsfrage that Heidegger set out to confront in his unfinished master work Being and Time (1927. The young Heidegger years before the publication of that work had been afforded an insight to an aspect of what would become his central concern from what at first might seem an unlikely source: the medieval philosopher and theologian John Duns Scotus.Scotus inspired Heidegger in so far as his thought was in proximity to “real life,” and while he would later move decisively away from the position he took in his ‘scotus Book,” in a move that has been referred to as the first “turn” in his thought from the ‘system of Catholicism” to liberal Protestantism, Scotus provided the young scholar with an insight into human individuality that would prove decisive in his mature work. Despite this move away from any kind of “onto-logic,” there is an element of Heidegger’s thought that is influenced by Scotus (1265/6-1308, one of the brightest stars of medieval philosophy. So, while my investigation is conducted with the fact of this turn in mind, my aim is to explore this element.

  19. Quantification of the effect of oil layer thickness on entrainment of surface oil

    NARCIS (Netherlands)

    Zeinstra-Helfrich, M.; Koops, W.; Dijkstra, K.; Murk, A.J.

    2015-01-01

    This study quantifies the effect of oil layer thickness on entrainment and dispersion of oil into seawater, using a plunging jet with a camera system. In contrast to what is generally assumed, we revealed that for the low viscosity “surrogate MC252 oil” we used, entrainment rate is directly proporti

  20. Accuracy of circadian entrainment under fluctuating light conditions : Contributions of phase and period responses

    NARCIS (Netherlands)

    Beersma, DGM; Daan, S; Hut, RA

    1999-01-01

    The accuracy with which a circadian pacemaker can entrain to an environmental 24-h zeitgeber signal depends on (a) characteristics of the entraining signal and (b) response characteristics and intrinsic stability of the pacemaker itself. Position of the sun, weather conditions, shades, and behaviora

  1. Quantification of the effect of oil layer thickness on entrainment of surface oil

    NARCIS (Netherlands)

    Zeinstra-Helfrich, M.; Koops, W.; Dijkstra, K.; Murk, A.J.

    2015-01-01

    This study quantifies the effect of oil layer thickness on entrainment and dispersion of oil into seawater, using a plunging jet with a camera system. In contrast to what is generally assumed, we revealed that for the low viscosity “surrogate MC252 oil” we used, entrainment rate is directly

  2. Parameterization of entrainment in a sheared convective boundary layer using a first-order jump model

    NARCIS (Netherlands)

    Kim, S.W.; Park, S.U.; Pino, D.; Vilà-Guerau de Arellano, J.

    2006-01-01

    Basic entrainment equations applicable to the sheared convective boundary layer (CBL) are derived by assuming an inversion layer with a finite depth, i.e., the first-order jump model. Large-eddy simulation data are used to determine the constants involved in the parameterizations of the entrainment

  3. Near-field entrainment in black smoker plumes

    Science.gov (United States)

    Smith, J. E.; Germanovich, L. N.; Lowell, R. P.

    2013-12-01

    In this work, we study the entrainment rate of the ambient fluid into a plume in the extreme conditions of hydrothermal venting at ocean floor depths that would be difficult to reproduce in the laboratory. Specifically, we investigate the flow regime in the lower parts of three black smoker plumes in the Main Endeavour Field on the Juan de Fuca Ridge discharging at temperatures of 249°C, 333°C, and 336°C and a pressure of 21 MPa. Such flow conditions are typical for ocean floor hydrothermal venting but would be difficult to reproduce in the laboratory. The centerline temperature was measured at several heights in the plume above the orifice. Using a previously developed turbine flow meter, we also measured the mean flow velocity at the orifice. Measurements were conducted during dives 4452 and 4518 on the submersible Alvin. Using these measurements, we obtained a range of 0.064 - 0.068 for values of the entrainment coefficient α, which is assumed constant near the orifice. This is half the value of α ≈ 0.12 - 0.13 that would be expected for plume flow regimes based on the existing laboratory results and field measurements in lower temperature and pressure conditions. In fact, α = 0.064 - 0.068 is even smaller than the value of α ≈ 0.075 characteristic of jet flow regimes and appears to be the lowest reported in the literature. Assuming that the mean value α = 0.066 is typical for hydrothermal venting at ocean floor depths, we then characterized the flow regimes of 63 black smoker plumes located on the Endeavor Segment of the Juan de Fuca Ridge. Work with the obtained data is ongoing, but current results indicate that approximately half of these black smokers are lazy in the sense that their plumes exhibit momentum deficits compared to the pure plume flow that develops as the plume rises. The remaining half produces forced plumes that show the momentum excess compared to the pure plumes. The lower value of the entrainment coefficient has important

  4. Phase-selective entrainment of nonlinear oscillator ensembles

    Science.gov (United States)

    Zlotnik, Anatoly; Nagao, Raphael; Kiss, István Z.; Li-Shin, Jr.

    2016-03-01

    The ability to organize and finely manipulate the hierarchy and timing of dynamic processes is important for understanding and influencing brain functions, sleep and metabolic cycles, and many other natural phenomena. However, establishing spatiotemporal structures in biological oscillator ensembles is a challenging task that requires controlling large collections of complex nonlinear dynamical units. In this report, we present a method to design entrainment signals that create stable phase patterns in ensembles of heterogeneous nonlinear oscillators without using state feedback information. We demonstrate the approach using experiments with electrochemical reactions on multielectrode arrays, in which we selectively assign ensemble subgroups into spatiotemporal patterns with multiple phase clusters. The experimentally confirmed mechanism elucidates the connection between the phases and natural frequencies of a collection of dynamical elements, the spatial and temporal information that is encoded within this ensemble, and how external signals can be used to retrieve this information.

  5. Entrainment of heterogeneous glycolytic oscillations in single cells

    CERN Document Server

    Gustavsson, A -K; Mehlig, B; Goksör, M

    2015-01-01

    Cell signaling, gene expression, and metabolism are affected by cell-cell heterogeneity and random changes in the environment. The effects of such fluctuations on cell signaling and gene expression have recently been studied intensively using single-cell experiments. In metabolism heterogeneity may be particularly important because it may affect synchronisation of metabolic oscillations, an important example of cell-cell communication. This synchronisation is notoriously difficult to describe theoretically as the example of glycolytic oscillations shows: neither is the mechanism of glycolytic synchronisation understood nor the role of cell-cell heterogeneity. To pin down the mechanism and to assess its robustness and universality we have experimentally investigated the entrainment of glycolytic oscillations in individual yeast cells by periodic external perturbations. We find that oscillatory cells synchronise through phase shifts and that the mechanism is insensitive to cell heterogeneity (robustness) and si...

  6. La nourriture dans les projets de développement: le cas d'un village indien en Equateur

    Directory of Open Access Journals (Sweden)

    1982-01-01

    Full Text Available Cet article est une réflexion sur l'importance culturelle que revêt la nourriture, et donc sur la nécessité au préalable d'une étude historique et anthropologique des populations concernées par les projets de développement. Comme contribution à cette préoccupation, l'auteur étudie les habitudes alimentaires de communautés indiennes, dans le cas précis d'un village équatorien, et tente d'évaluer les éventuelles traditions qui les sous tendent. El presente artículo ofrece una reflexión acerca de la importancia cultural que reviste la alimentación, y por lo tanto, de la necesidad, como requisito previo a los proyectos de desarrollo, de estudios históricos y antropológicos de las poblaciones afectadas por dichos proyectos. Como contribución a esta preocupación, la autora estudia las costumbres alimenticias de unas comunidades indígenas, en el caso preciso de un pueblo ecuatoriano, e intenta evaluar las eventuales tradiciones en que estriban. This article offers a discussion of the cultural importance of food, and the consequent need for historical and anthropological studies of societies affected by development projects. As a contribution to this problem, the author studies the patterns of food consumption of Indian communities, in the specific case of an Ecuadorian village, and seeks to evaluate the possible traditions which underlie them.

  7. How oil properties and layer thickness determine the entrainment of spilled surface oil.

    Science.gov (United States)

    Zeinstra-Helfrich, Marieke; Koops, Wierd; Murk, Albertinka J

    2016-09-15

    Viscosity plays an important role in dispersion of spilled surface oil, so does adding chemical dispersants. For seven different oil grades, entrainment rate and initial droplet size distribution were investigated using a plunging jet apparatus with coupled camera equipment and subsequent image analysis. We found that amount of oil entrained is proportional to layer thickness and largely independent of oil properties: A dispersant dose of 1:200 did not result in a significantly different entrainment rate compared to no dispersants. Oil viscosity had a minor to no influence on entrainment rate, until a certain threshold above which entrainment was impeded. The mean droplet size scales with the modified Weber number as described by Johansen. The obtained results can help improve dispersion algorithms in oil spill fate and transport models, to aid making an informed decision about application of dispersants.

  8. Inhomogeneity of action potential waveshape assists frequency entrainment of cardiac pacemaker cells.

    Science.gov (United States)

    Cloherty, S L; Lovell, N H; Celler, B G; Dokos, S

    2001-10-01

    In this paper, we have employed ionic models of sinoatrial node cells to investigate the synchronization of a pair of coupled cardiac pacemaker cells from central and peripheral regions of the sinoatrial node. The free-running cycle length of the cell models was perturbed using two independent techniques and the minimum coupling conductance required to achieve frequency entrainment was used to assess the relative ease with which various cell pairs achieve entrainment. The factors effecting entrainment were further investigated using single-cell models paced with an artificial biphasic coupling current. Our simulation results suggest that dissimilar cell types, those with largely different upstroke velocities entrain more easily, that is, they require less coupling conductance to achieve 1:1 frequency entrainment. We, therefore, propose that regional variation in action-potential waveshape within the sinoatrial node assists frequency synchronization in vivo.

  9. On turbulent entrainment and dissipation in dilute polymer solutions

    Science.gov (United States)

    Liberzon, A.; Holzner, M.; Lüthi, B.; Guala, M.; Kinzelbach, W.

    2009-03-01

    We present a comparative experimental study of a turbulent flow developing in clear water and dilute polymer solutions (25 and 50 wppm polyethylene oxide). The flow is forced by a planar grid that oscillates vertically with stroke S and frequency f in a square container of initially still fluid. Two-component velocity fields are measured in a vertical plane passing through the center of the tank by using time resolved particle image velocimetry. After the forcing is initiated, a turbulent layer develops that is separated from the initially irrotational fluid by a sharp interface, the so-called turbulent/nonturbulent interface (TNTI). The turbulent region grows in time through entrainment of surrounding fluid until the fluid in the whole container is in turbulent motion. From the comparison of the experiments in clear water and polymer solutions we conclude: (i) Polymer additives modify the large scale shape of the TNTI. (ii) Both, in water and in the polymer solution the mean depth of the turbulent layer, H(t ), follows the theoretical prediction for Newtonian fluids H(t )∝√Kt , where K ∝S2f is the "grid action." (iii) We find a larger grid action for dilute polymer solutions than for water. As a consequence, the turbulent kinetic energy of the flow increases and the rate of energy input becomes higher. (iv) The entrainment rate β =ve/vrms (where ve=dH/dt is the interface propagation velocity and vrms is the root mean square of the vertical velocity) is lower for polymers (βp≈0.7) than for water (βw≈0.8). The measured values for β are in good agreement with similarity arguments, from which we estimate that in our experiment about 28% of the input energy is dissipated by polymers.

  10. Out-of-synchrony speech entrainment in developmental dyslexia.

    Science.gov (United States)

    Molinaro, Nicola; Lizarazu, Mikel; Lallier, Marie; Bourguignon, Mathieu; Carreiras, Manuel

    2016-08-01

    Developmental dyslexia is a reading disorder often characterized by reduced awareness of speech units. Whether the neural source of this phonological disorder in dyslexic readers results from the malfunctioning of the primary auditory system or damaged feedback communication between higher-order phonological regions (i.e., left inferior frontal regions) and the auditory cortex is still under dispute. Here we recorded magnetoencephalographic (MEG) signals from 20 dyslexic readers and 20 age-matched controls while they were listening to ∼10-s-long spoken sentences. Compared to controls, dyslexic readers had (1) an impaired neural entrainment to speech in the delta band (0.5-1 Hz); (2) a reduced delta synchronization in both the right auditory cortex and the left inferior frontal gyrus; and (3) an impaired feedforward functional coupling between neural oscillations in the right auditory cortex and the left inferior frontal regions. This shows that during speech listening, individuals with developmental dyslexia present reduced neural synchrony to low-frequency speech oscillations in primary auditory regions that hinders higher-order speech processing steps. The present findings, thus, strengthen proposals assuming that improper low-frequency acoustic entrainment affects speech sampling. This low speech-brain synchronization has the strong potential to cause severe consequences for both phonological and reading skills. Interestingly, the reduced speech-brain synchronization in dyslexic readers compared to normal readers (and its higher-order consequences across the speech processing network) appears preserved through the development from childhood to adulthood. Thus, the evaluation of speech-brain synchronization could possibly serve as a diagnostic tool for early detection of children at risk of dyslexia. Hum Brain Mapp 37:2767-2783, 2016. © 2016 Wiley Periodicals, Inc.

  11. A neuropeptide speeds circadian entrainment by reducing intercellular synchrony.

    Science.gov (United States)

    An, Sungwon; Harang, Rich; Meeker, Kirsten; Granados-Fuentes, Daniel; Tsai, Connie A; Mazuski, Cristina; Kim, Jihee; Doyle, Francis J; Petzold, Linda R; Herzog, Erik D

    2013-11-12

    Shift work or transmeridian travel can desynchronize the body's circadian rhythms from local light-dark cycles. The mammalian suprachiasmatic nucleus (SCN) generates and entrains daily rhythms in physiology and behavior. Paradoxically, we found that vasoactive intestinal polypeptide (VIP), a neuropeptide implicated in synchrony among SCN cells, can also desynchronize them. The degree and duration of desynchronization among SCN neurons depended on both the phase and the dose of VIP. A model of the SCN consisting of coupled stochastic cells predicted both the phase- and the dose-dependent response to VIP and that the transient phase desynchronization, or "phase tumbling", could arise from intrinsic, stochastic noise in small populations of key molecules (notably, Period mRNA near its daily minimum). The model also predicted that phase tumbling following brief VIP treatment would accelerate entrainment to shifted environmental cycles. We tested this using a prepulse of VIP during the day before a shift in either a light cycle in vivo or a temperature cycle in vitro. Although VIP during the day does not shift circadian rhythms, the VIP pretreatment approximately halved the time required for mice to reentrain to an 8-h shifted light schedule and for SCN cultures to reentrain to a 10-h shifted temperature cycle. We conclude that VIP below 100 nM synchronizes SCN cells and above 100 nM reduces synchrony in the SCN. We show that exploiting these mechanisms that transiently reduce cellular synchrony before a large shift in the schedule of daily environmental cues has the potential to reduce jet lag.

  12. Implantation des sites de soins communautaires en République Démocratique du Congo: consécration d'un double standard dans l'accès aux soins

    Science.gov (United States)

    Dunia, Gisèle Mawazo Binti

    2013-01-01

    Depuis 2005, la République Démocratique du Congo a amorcé l'implantation des sites de soins communautaires. Cette stratégie a pour objectif de rapprocher les services de santé des populations éloignées. Bien que cela parte d'une bonne intention, elle résulte, à notre sens, en une consécration d'un système de santé à deux vitesses. En effet, les populations vivant en ville ont accès à des soins prestés par des agents de santé formés alors que celles vivant en milieu rural reculé ont pour prestataires de soins des relais communautaires. Cette situation marginalise encore plus des populations dont la situation géographique est déjà préoccupante. Pourtant, la population est prête à parcourir des kilomètres en échange d'un service qu'elle estime de qualité. PMID:23785563

  13. Entrainment of visual steady-state responses is modulated by global spatial statistics.

    Science.gov (United States)

    Nguyen, Thomas; Kuntzelman, Karl; Miskovic, Vladimir

    2017-07-01

    The rhythmic delivery of visual stimuli evokes large-scale neuronal entrainment in the form of steady-state oscillatory field potentials. The spatiotemporal properties of stimulus drive appear to constrain the relative degrees of neuronal entrainment. Specific frequency ranges, for example, are uniquely suited for enhancing the strength of stimulus-driven brain oscillations. When it comes to the nature of the visual stimulus itself, studies have used a plethora of inputs ranging from spatially unstructured empty fields to simple contrast patterns (checkerboards, gratings, stripes) and complex arrays (human faces, houses, natural scenes). At present, little is known about how the global spatial statistics of the input stimulus influence entrainment of scalp-recorded electrophysiological signals. In this study, we used rhythmic entrainment source separation of scalp EEG to compare stimulus-driven phase alignment for distinct classes of visual inputs, including broadband spatial noise ensembles with varying second-order statistics, natural scenes, and narrowband sine-wave gratings delivered at a constant flicker frequency. The relative magnitude of visual entrainment was modulated by the global properties of the driving stimulus. Entrainment was strongest for pseudo-naturalistic broadband visual noise patterns in which luminance contrast is greatest at low spatial frequencies (a power spectrum slope characterized by 1/ƒ(-2)).NEW & NOTEWORTHY Rhythmically modulated visual stimuli entrain the activity of neuronal populations, but the effect of global stimulus statistics on this entrainment is unknown. We assessed entrainment evoked by 1) visual noise ensembles with different spectral slopes, 2) complex natural scenes, and 3) narrowband sinusoidal gratings. Entrainment was most effective for broadband noise with naturalistic luminance contrast. This reveals some global properties shaping stimulus-driven brain oscillations in the human visual system. Copyright © 2017

  14. The performative pleasure of imprecision: a diachronic study of entrainment in music performance.

    Science.gov (United States)

    Geeves, Andrew; McIlwain, Doris J; Sutton, John

    2014-01-01

    This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and smoothly transition into unprecedented performance territory. We use this moment of live performance to work back through the fieldwork data, building a diachronic study of the development and bases of entrainment in live music performance. We introduce the concept of entrainment and profile previous theory and research relevant to entrainment in music performance. After outlining our methodology, we trace the evolution of the structure of the piece of music from first rehearsal to final performance. Using video clip analysis, interviews and field notes we consider how entrainment shaped and was shaped by the moment of performance in focus. The sense of trust between quartet musicians is established through entrainment processes, is consolidated via smooth adaptation to the threats of disruption. Non-verbal communicative exchanges, via eye contact, gesture, and spatial proximity, sustain entrainment through phase shifts occurring swiftly and on the fly in performance contexts. These exchanges permit smooth adaptation promoting trust. This frees the quartet members to play with the potential disturbance of equilibrium inherent in entrained relationships and to play with this tension in an improvisatory way that enhances audience engagement and the live quality of performance.

  15. The performative pleasure of imprecision: a diachronic study of entrainment in music performance

    Directory of Open Access Journals (Sweden)

    Andrew eGeeves

    2014-10-01

    Full Text Available This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and smoothly transition into unprecedented performance territory. We use this moment of live performance to work back through the fieldwork data, building a diachronic study of the development and bases of entrainment in live music performance. We introduce the concept of entrainment and profile previous theory and research relevant to entrainment in music performance. After outlining our methodology, we trace the evolution of the structure of the piece of music from first rehearsal to final performance. Using video clip analysis, interviews and field notes we consider how entrainment shaped and was shaped by the moment of performance in focus. The sense of trust between quartet musicians is established through entrainment processes, is consolidated via smooth adaptation to the threats of disruption. Nonverbal communicative exchanges, via eye contact, gesture and spatial proximity, sustain entrainment through phase shifts occurring swiftly and on the fly in performance contexts. These exchanges permit smooth adaptation promoting trust. This frees the quartet members to play with the potential disturbance of equilibrium inherent in entrained relationships and to play with this tension in an improvisatory way that enhances audience engagement and the live quality of performance.

  16. Effets d'un hydrocarbure aromatique polycyclique et d'un PCB sur les activités de métabolisation des xénobiotiques de la truite arc-en-ciel (O. mykiss

    Directory of Open Access Journals (Sweden)

    CRAVEDI J. P.

    1998-07-01

    Full Text Available Des truites arc-en-ciel immatures ont été soumises à des conditions statiques d'exposition à 10 et 100 µg/l de 3,3', 4,4'-tétrachlorobiphényle (TCB ou de benzo(apyrène (BaP dissous dans l'acétone, pendant 72 h, puis transférées en eau courante non contaminée. Parallèlement un groupe de poissons a servi de lot témoin. Une partie des poissons a été sacrifiée en fin de période d'exposition, l'autre partie faisant l'objet d'un abattage après 2 semaines en eau propre. Le foie, les rosettes olfactives, les branchies et le rein ont été prélevés sur les poissons et, des microsomes et cytosols ont été préparés pour chacun des tissus par ultracentrifugation dans un tampon approprié. Les activités éthoxyrésorufine-o-dééthylase (EROD, glucuronosyl transférase (UDPGT et glutathion-Stransférase (GST ont été mesurées. Les résultats de l'exposition au BaP montrent qu'aux deux concentrations testées, l'activité EROD a été significativement augmentée par rapport au lot témoin, pour le foie (x 11 à 33 fois et la branchie (x 5 à 7 fois. Seule la dose la plus élevée a permis d'augmenter l'activité de cette enzyme dans le rein et la rosette olfactive. A la fin de la période de dépuration, il n'est observé aucune différence significative entre les lots traités et témoins. Les transferases apparaissent peu sensibles au B(aP. Après 72 h d'exposition au TCB, l'activité EROD du foie, des branchies, des rosettes et du rein est très significativement augmentée (5 à 50 fois selon le tissu par rapport au témoin, aux deux concentrations testées. Cette induction est encore plus nette après la période de 2 semaines en eau propre. L'activité UDPGT hépatique est doublée en fin de traitement pour les deux doses et se maintient à ce niveau au cours de la période de dépuration. Les GST sont légèrement induites dans le foie après les 15 jours de dépuration. Ce travail confirme la grande sensibilité de l

  17. Traitement de surface par explosif du cuivre polycristallin : caractérisation microstructurale et comportement en fatigue plastique

    OpenAIRE

    1991-01-01

    Une nouvelle technique de traitement de surface à l'aide d'un explosif primaire déposé en couche mince a été utilisée sur du cuivre pur polycristallin. L'état de surface après traitement reste de très bonne qualité, surtout comparé aux surfaces grenaillées. La zone traitée s'étend sur une profondeur de quelques centaines de microns et le profil de microdureté montre une importante augmentation de dureté avec un maximum en surface pouvant atteindre 100%. La micrcrostructure, observée par micro...

  18. Modélisation par éléments finis d'ancrage à câble

    OpenAIRE

    DU PUY, Hugues; Dieng, Lamine; UNIVERSITE DE NANTES; LABORATOIRE CENTRAL DES PONTS ET CHAUSSEES - LCPC

    2010-01-01

    Les câbles jouent un rôle crucial dans les ouvrages d'art et plus particulièrement pour les ponts (haubanés, suspendus ou précontraints). Ces câbles ont pour principale mission de transmettre les forces du tablier (poids propres de la structure, trafic routier, intempéries) aux piliers. L'attache d'une extrémité d'un câble élémentaire sur le tablier du pont ou sur les massifs d'ancrage des berges est réalisée par une pièce massive en fonte ou en acier moulé appelée « culot » ou « culot d'a...

  19. Lidar measurements of the atmospheric entrainment zone and the potential temperature jump across the top of the mixed layer

    Science.gov (United States)

    Boers, R.; Eloranta, E. W.

    1986-01-01

    Lidar data of the atmospheric entrainment zone from six days of clear air convection obtained in central Illinois during July 1979 are presented. A new method to measure the potential temperature jump across the entrainment zone based on only one temperature sounding and continuous lidar measurements of the mixed layer height is developed. An almost linear dependence is found between the normalized entrainment rate and the normalized thickness of the entrainment zone.

  20. Flow Dynamics and Sediment Entrainment in Natural Turbidity Currents Inferred from Numerical Modeling

    Science.gov (United States)

    Traer, M. M.; Hilley, G. E.; Fildani, A.

    2009-12-01

    Submarine turbidity currents derive their momentum from gravity acting upon the density contrast between sediment-laden and clear water, and so unlike fluvial systems, the dynamics of such flows are inextricably linked to the rates at which they deposit and entrain sediment. We have analyzed the sensitivity of the growth and maintenance of turbidity currents to sediment entrainment and deposition using the layer-averaged equations of conservation of fluid and sediment mass, and conservation of momentum and turbulent kinetic energy. Our model results show that the dynamics of turbidity currents are extremely sensitive to the functional form and empirical constants of the relationship between sediment entrainment and friction velocity. Data on the relationship between sediment entrainment and friction velocity for submarine density flows are few and as a result, entrainment formulations are populated with data from sub-aerial flows not driven by the density contrast between clear and turbid water. If we entertain the possibility that sediment entrainment in sub-aerial rivers is different than in dense underflows, flow parameters such as velocity, height, and concentration were found nearly impossible to predict beyond a few hundred meters based on the limited laboratory data available that constrain the sediment entrainment process in turbidity currents. The sensitivity of flow dynamics to the functional relationship between friction velocity and sediment entrainment indicates that independent calibration of a sediment entrainment law in the submarine environment is necessary to realistically predict the dynamics of these flows and the resulting patterns of erosion and deposition. To calibrate such a relationship, we have developed an inverse methodology that utilizes existing submarine channel morphology as a means of constraining the sediment entrainment function parameters. We use a Bayesian Metropolis-Hastings sampler to determine the sediment entrainment

  1. De l'organique au minéral : Étude expérimentale et modélisation de la transformation d'un précurseur polysilazane en "carbonitrure de silicium"

    OpenAIRE

    Salvetti, Marie-Gabrielle

    1994-01-01

    215 pages; No English abstract; Le but de cette étude est de comprendre la transformation thermique d'un polysilazane en carbonitrure de silicium afin de maitriser la composition de la fibre céramique dont il est le précurseur. Les deux phénomènes qu'il convient d'éviter dans l'élaboration de telles fibres sont l'oxydation et la cristallisation qui provoque la perte totale de résistance mécanique. Les différentes étapes de la transformation sont, dans un premier temps, ce que l'on désigne par...

  2. Maîtrise foncière et protection d'un captage d'eau potable : enseignements tirés d'une expérience originale

    OpenAIRE

    Pivot, J.M.; Aznar, O.

    2000-01-01

    L'acquisition de la propriété foncière est une solution intéressante pour assurer la maîtrise de la qualité de l'eau d'un captage, lorsque l'usage productif de certains espaces doit être fortement restreint. Mais de tels projets d'acquisition peuvent se heurter à un marché foncier bloqué par des propriétaires en position de monopole. En se basant sur une opération réelle, cet article détaille la nature des problèmes fonciers en cause et les caractéristiques du dispositif technique retenu ayan...

  3. 217 L'entourage d'un Fait d'expression Comme Guide a la ...

    African Journals Online (AJOL)

    Ike Odimegwu

    ... devant des choix à faire mais l'entourage d'un fait d'expression aide le traducteur à ... context, situation of communication, gestures, facial expressions and intonation ..... Ottawa : Presse de l'université d'Ottawa, 2e édition, 1982. Jakobson ...

  4. Los derechos humanos a la luz del pensamiento de Juan Duns Scoto

    OpenAIRE

    2012-01-01

    Con este aporte, quiero presentar a usted querido lector y lectora una aproximación a un problema tan cercano a nosotros en Colombia, como es el caso de los Derechos Humanos, iluminando dicha realidad desde un autor franciscano: Juan Duns Scoto, quien es recordado y celebrado este año (2008) en sus 700 años de muerte.

  5. Dark Awakening : Creació d'un videojoc en Unity

    OpenAIRE

    Medina Torregrosa, Daniel

    2016-01-01

    Desenvolupament d'un videojoc de ciència ficció en Unity per a web i PC. Desarrollo de un videojuego de ciencia ficción en Unity para web y PC. Sci-fi videogame development in Unity for web and PC.

  6. L'Utopie comme esquisse d'un avenir meilleur

    Directory of Open Access Journals (Sweden)

    Hervé Ondoua

    2012-12-01

    Full Text Available Le postmodernisme se donne explicitement comme une philosophie de la mondialisation. En occident, Jacques Derrida, par sa déconstruction, est l’un des penseurs qui anime le débat postmoderne en considérant que notre ère manque la fin de rationalité, du progrès et de la recherche d’un sens. La déconstruction se définit comme l’ensemble des techniques et stratégies utilisées par Derrida pour démonter, fissurer et déplacer toute logique universelle. Par le mécanisme de la différance, l’homme sort de tout cadre originaire (grands ensembles, méta récits, seul demeure la trace. L’homme pris dans la trace marque son refus de solidarité avec tout centre, tout principe, toute origine, etc. Cette idée est radicalisée par le légiste, personnage emblématique dans l���Utopie de Thomas More. En effet, le légiste fait l’éloge de la justice sévère anglaise. Partant de la théorie socio-biologiste selon laquelle les comportements sociaux sont génétiques, le légiste dans l’Utopie de More soutient qu’il faut une justice sévère, inflexible, rigide pour nettoyer la cité de ces maux. Dans ce sens, il faut condamner autant d’individus à la potence, car les maux sociaux sont naturels et innées. C’est contre cette approche néolibérale que s’insurge Thomas More. Tout comme les mouvements de gauches, l’Utopie de More explique les maux sociaux par les injustices sociales, la démission de la société, et surtout le manque de l’éducation. Du coup, avec l’Utopie, il s’agit de relativiser le monde dans lequel nous vivons : un autre monde est possible que celui dans lequel nous vivons. Partant delà, l’utopie notamment celle de Francis Bacon ou Thomas More, n’est-elle pas un genre littéraire altermondialiste ? Si la logique néolibérale impose son diktat et pose le principe selon lequel il n’y a pas d’alternative autre que ce que nous offre le capitalisme, ne faut-il pas voir dans l’Utopie, un

  7. Performance testing of passive autocatalytic recombiners (PARs)

    Energy Technology Data Exchange (ETDEWEB)

    Blanchat, T. [Sandia National Laboratories, Albuquerque, NM (United States); Malliakos, A. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)

    1997-03-01

    Passive autocatalytic recombiners (PARs) have been under consideration in the U.S. as a combustible gas control system in advanced light water reactor (ALWR) containments for design basis and severe accidents. PARs do not require a source of power. Instead they use palladium or platinum as a catalyst to recombine hydrogen and oxygen gases into water vapor upon contact with the catalyst. Energy from the recombination of hydrogen with oxygen is released at a relatively slow but continuous rate into the containment which prevents the pressure from becoming too high. The heat produced creates strong buoyancy effects which increases the influx of the surrounding gases to the recombiner. These natural convective flow currents promote mixing of combustible gases in the containment. PARs are self-starting and self-feeding under a very wide range of conditions. The recombination rate of the PAR system needs to be great enough to keep the concentration of hydrogen (or oxygen) below acceptable limits. There are several catalytic recombiner concepts under development worldwide. The USNRC is evaluating a specific design of a PAR which is in an advanced stage of engineering development and has been proposed for ALWR designs. Sandia National laboratories (SNL), under the sponsorship and the direction of the USNRC, is conducting an experimental program to evaluate the performance of PARs. The PAR will be tested at the SURTSEY facility at SNL. The test plan currently includes the following experiments: experiments will be conducted to define the startup characteristics of PARs (i.e., to define what is the lowest hydrogen concentration that the PAR starts recombining the hydrogen with oxygen); experiments will be used to define the hydrogen depletion rate of PARs as a function of hydrogen concentration; and experiments will be used to define the PAR performance in the presence of high concentrations of steam. (author)

  8. Unscreened water-diversion pipes pose an entrainment risk to the threatened green sturgeon, Acipenser medirostris.

    Directory of Open Access Journals (Sweden)

    Timothy D Mussen

    Full Text Available Over 3,300 unscreened agricultural water diversion pipes line the levees and riverbanks of the Sacramento River (California watershed, where the threatened Southern Distinct Population Segment of green sturgeon, Acipenser medirostris, spawn. The number of sturgeon drawn into (entrained and killed by these pipes is greatly unknown. We examined avoidance behaviors and entrainment susceptibility of juvenile green sturgeon (35±0.6 cm mean fork length to entrainment in a large (>500-kl outdoor flume with a 0.46-m-diameter water-diversion pipe. Fish entrainment was generally high (range: 26-61%, likely due to a lack of avoidance behavior prior to entering inescapable inflow conditions. We estimated that up to 52% of green sturgeon could be entrained after passing within 1.5 m of an active water-diversion pipe three times. These data suggest that green sturgeon are vulnerable to unscreened water-diversion pipes, and that additional research is needed to determine the potential impacts of entrainment mortality on declining sturgeon populations. Data under various hydraulic conditions also suggest that entrainment-related mortality could be decreased by extracting water at lower diversion rates over longer periods of time, balancing agricultural needs with green sturgeon conservation.

  9. Parameterization for the Depth of the Entrainment Zone above the Convectively Mixed Layer

    Institute of Scientific and Technical Information of China (English)

    SUN Jianning; JIANG Weimei; CHEN Ziyun; YUAN Renmin

    2005-01-01

    It has been noted that when the convective Richardson number Ri* is used to characterize the depth of the entrainment zone, various parameterization schemes can be obtained. This situation is often attributed to the invalidity of parcel theory. However, evidence shows that the convective Richardson number Ri*might be an improper characteristic scaling parameter for the entrainment process. An attempt to use an innovative parameter to parameterize the entrainment-zone thickness has been made in this paper.Based on the examination of the data of water-tank experiments and atmospheric measurements, it is found that the total lapse rate of potential temperature across the entrainment zone is proportional to that of the capping inversion layer. Inserting this relationship into the so-called parcel theory, it thus gives a new parameterization scheme for the depth of the entrainment zone. This scheme includes the lapse rate of the capping inversion layer that plays an important role in the entrainment process. Its physical representation is reasonable. The new scheme gives a better ordering of the data measured in both watertank and atmosphere as compared with the traditional method using Ri*. These indicate that the parcel theory can describe the entrainment process suitably and that the new parameter is better than Ri*.

  10. Unscreened water-diversion pipes pose an entrainment risk to the threatened green sturgeon, Acipenser medirostris.

    Science.gov (United States)

    Mussen, Timothy D; Cocherell, Dennis; Poletto, Jamilynn B; Reardon, Jon S; Hockett, Zachary; Ercan, Ali; Bandeh, Hossein; Kavvas, M Levent; Cech, Joseph J; Fangue, Nann A

    2014-01-01

    Over 3,300 unscreened agricultural water diversion pipes line the levees and riverbanks of the Sacramento River (California) watershed, where the threatened Southern Distinct Population Segment of green sturgeon, Acipenser medirostris, spawn. The number of sturgeon drawn into (entrained) and killed by these pipes is greatly unknown. We examined avoidance behaviors and entrainment susceptibility of juvenile green sturgeon (35±0.6 cm mean fork length) to entrainment in a large (>500-kl) outdoor flume with a 0.46-m-diameter water-diversion pipe. Fish entrainment was generally high (range: 26-61%), likely due to a lack of avoidance behavior prior to entering inescapable inflow conditions. We estimated that up to 52% of green sturgeon could be entrained after passing within 1.5 m of an active water-diversion pipe three times. These data suggest that green sturgeon are vulnerable to unscreened water-diversion pipes, and that additional research is needed to determine the potential impacts of entrainment mortality on declining sturgeon populations. Data under various hydraulic conditions also suggest that entrainment-related mortality could be decreased by extracting water at lower diversion rates over longer periods of time, balancing agricultural needs with green sturgeon conservation.

  11. Quadrupedal Locomotion-Respiration Entrainment and Metabolic Economy in Cross-Country Skiers.

    Science.gov (United States)

    Boldt, Kevin; Killick, Anthony; Herzog, Walter

    2016-02-01

    A 1:1 locomotion-respiration entrainment is observed in galloping quadrupeds, and is thought to improve running economy. However, this has not been tested directly in animals, as animals cannot voluntarily disrupt this entrainment. The purpose of this study was to evaluate metabolic economy in a human gait involving all four limbs, cross-country skiing, in natural entrainment and forced nonentrainment. Nine elite cross-country skiers roller skied at constant speed using the 2-skate technique. In the first and last conditions, athletes used the natural entrained breathing pattern: inhaling with arm recovery and exhaling with arm propulsion, and in the second condition, the athletes disentrained their breathing pattern. The rate of oxygen uptake (VO2) and metabolic rate (MR) were measured via expired gas analysis. Propulsive forces were measured with instrumented skis and poles. VO2 and MR increased by 4% and 5% respectively when skiers used the disentrained compared with the entrained breathing pattern. There were no differences in ski or pole forces or in timing of the gait cycle between conditions. We conclude that breathing entrainment reduces metabolic cost of cross-country skiing by approximately 4%. Further, this reduction is likely a result of the entrainment rather than alterations in gait mechanics.

  12. Neurobiological Foundations of Neurologic Music Therapy: Rhythmic Entrainment and the Motor System

    Directory of Open Access Journals (Sweden)

    Michael eThaut

    2015-02-01

    Full Text Available AbstractEntrainment is defined by a temporal locking process in which one system’s motion or signal frequency entrains the frequency of another system. This process is a universal phenomenon that can be observed in physical (e.g., pendulum clocks and biological systems (e.g. fire flies. However, entrainment can also be observed between human sensory and motor systems. The function of rhythmic entrainment in rehabilitative training and learning was established for the first time by Thaut and colleagues in several research studies in the early 1990s. It was shown that the inherent periodicity of auditory rhythmic patterns could entrain movement patterns in patients with movement disorders (see for a review: Thaut et al, 1999. Physiological, kinematic and behavioral movement analysis showed very quickly that entrainment cues not only changed the timing of movement but also improved spatial and force parameters. Mathematical models have shown that anticipatory rhythmic templates as critical time constraints can result in the complete specification of the dynamics of a movement over the entire movement cycle, thereby optimizing motor planning and execution. Furthermore, temporal rhythmic entrainment has been successfully extended into applications in cognitive rehabilitation and speech and language rehabilitation, and thus become one of the major neurological mechanisms linking music and rhythm to brain rehabilitation. These findings provided a scientific basis for the development of Neurologic Music Therapy.

  13. Neurobiological foundations of neurologic music therapy: rhythmic entrainment and the motor system

    Science.gov (United States)

    Thaut, Michael H.; McIntosh, Gerald C.; Hoemberg, Volker

    2015-01-01

    Entrainment is defined by a temporal locking process in which one system’s motion or signal frequency entrains the frequency of another system. This process is a universal phenomenon that can be observed in physical (e.g., pendulum clocks) and biological systems (e.g., fire flies). However, entrainment can also be observed between human sensory and motor systems. The function of rhythmic entrainment in rehabilitative training and learning was established for the first time by Thaut and colleagues in several research studies in the early 1990s. It was shown that the inherent periodicity of auditory rhythmic patterns could entrain movement patterns in patients with movement disorders (see for a review: Thaut et al., 1999). Physiological, kinematic, and behavioral movement analysis showed very quickly that entrainment cues not only changed the timing of movement but also improved spatial and force parameters. Mathematical models have shown that anticipatory rhythmic templates as critical time constraints can result in the complete specification of the dynamics of a movement over the entire movement cycle, thereby optimizing motor planning and execution. Furthermore, temporal rhythmic entrainment has been successfully extended into applications in cognitive rehabilitation and speech and language rehabilitation, and thus become one of the major neurological mechanisms linking music and rhythm to brain rehabilitation. These findings provided a scientific basis for the development of neurologic music therapy. PMID:25774137

  14. Geomorphic evolution of Dehra Dun, NW Himalaya: Tectonics and climatic coupling

    Science.gov (United States)

    Sinha, Swati; Sinha, Rajiv

    2016-08-01

    The Dehra Dun is a good example of a piggyback basin formed from the growth of the Siwalik hills. Two large rivers, the Ganga and the Yamuna, and their tributaries deposit a significant part of their sediment load in the Dun before they enter the Gangetic plains. This work documents the geomorphic complexities and landform evolution of the Dehra Dun through geomorphic mapping and chronostratigraphic investigation of the incised fan sections. Lesser Himalayan hills, inner and outer dissected hills, isolated hills, proximal fan, distal fan, dip slope unit, floodplains, and terraces are the major geomorphic units identified in the area. Isolated hills of fan material (IHF), proximal fan (PF), and distal fan (DF) are identified as fan surfaces from north to south of the valley. The OSL based chronology of the fan sediments suggests that the IHF is the oldest fan consisting of debris flow deposits with a maximum age of ~ 43 ka coinciding with the precipitation minima. The proximal fan consisting of sheet flow deposits represents the second phase of aggradation between 34 and 21 ka caused by shifting of deposition locus downstream triggered by high sediment supply that exceeded the transport capacity. The distal fan was formed by braided river deposits during 20-11 ka coinciding with the deglacial period. The IHF, PF and DF surfaces were abandoned by distinct incision phases during ~ 40-35, ~ 20-17, and ~ 11-4 ka respectively. A minor phase of terrace deposition in Dehra Dun was documented during 3-2 ka. Our results thus show that the evolutionary history of the alluvial fans in Dehra Dun was primarily controlled by climatic forcing with tectonics playing a minimum role in terms of providing accommodation space and sediment production.

  15. Evaluation concurrentielle du torseur de contact pneumatique/chaussée au moyen d'une roue dynamométrique et d'un système intégré à l'infrastructure routière

    OpenAIRE

    COIRET, A

    2006-01-01

    La connaissance des efforts exercés par les roues d'un véhicule sur une chaussée est primordiale pour les études sur les pertes de contrôle (théoriques, simulées, expérimentales). En particulier, pour les études expérimentales, la mesure de ces efforts, rapportée aux glissements et dérives des pneumatiques aide à modéliser le comportement du véhicule. Face aux coûteuses roues dynamométriques traditionnellement employées pour cela, un système alternatif a récemment été développé par le LCPC. C...

  16. Droplet entrainment correlation in vertical upward co-current annular two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, Pravin [Purdue University, School of Nuclear Engineering, 400 Central Dr., West Lafayette, IN 47907-2017 (United States)], E-mail: psawant@purdue.edu; Ishii, Mamoru [Purdue University, School of Nuclear Engineering, 400 Central Dr., West Lafayette, IN 47907-2017 (United States); Mori, Michitsugu [Tokyo Electric Power Co., Inc., R and D Center, 4-1 Egasaki-cho, Tsurumi-ku, Yokohama 230-8510 (Japan)], E-mail: michitsugu.mori@tepco.co.jp

    2008-06-15

    Upward annular two-phase flow in a vertical tube is characterized by the presence of liquid film on the tube wall and entrained droplet laden gas phase flowing through the tube core. Entrainment fraction in annular flow is defined as a fraction of the total liquid flow flowing in the form of droplets through the central gas core. Its prediction is important for the estimation of pressure drop and dryout in annular flow. In the following study, measurements of entrainment fraction have been obtained in vertical upward co-current air-water annular flow covering wide ranges of pressure and flow conditions. Comparison of the experimental data with the existing entrainment fraction prediction correlations revealed their inadequacies in simulating the trends observed under high flow and high pressure conditions. Furthermore, several correlations available in the literature are implicit and require iterative calculations. Analysis of the experimental data showed that the non-dimensional numbers, Weber number (We = {rho}{sub g}{sup 2}D/{sigma}({delta}{rho}/{rho}{sub g}){sup 1/4}) and liquid phase Reynolds number (Re{sub f} = {rho}{sub f}D/{mu}{sub f}), successfully collapse the data. In view of this, simple, explicit correlation was developed based on these non-dimensional numbers for the prediction of entrainment fraction. The new correlation successfully predicted the trends under the high flow and high pressure conditions observed in the current experimental data and the data available in open literature. However, in order to use the proposed correlation it is necessary to predict the maximum possible entrainment fraction (or limiting entrainment fraction). In the current analysis, an experimental data based correlation was used for this purpose. However, a better model or correlation is necessary for the maximum possible entrainment fraction. A theoretical discussion on the mechanism and modeling of the maximum possible entrainment fraction

  17. Estimation of convective entrainment properties from a cloud-resolving model simulation during TWP-ICE

    Science.gov (United States)

    Zhang, Guang J.; Wu, Xiaoqing; Zeng, Xiping; Mitovski, Toni

    2016-10-01

    The fractional entrainment rate in convective clouds is an important parameter in current convective parameterization schemes of climate models. In this paper, it is estimated using a 1-km-resolution cloud-resolving model (CRM) simulation of convective clouds from TWP-ICE (the Tropical Warm Pool-International Cloud Experiment). The clouds are divided into different types, characterized by cloud-top heights. The entrainment rates and moist static energy that is entrained or detrained are determined by analyzing the budget of moist static energy for each cloud type. Results show that the entrained air is a mixture of approximately equal amount of cloud air and environmental air, and the detrained air is a mixture of ~80 % of cloud air and 20 % of the air with saturation moist static energy at the environmental temperature. After taking into account the difference in moist static energy between the entrained air and the mean environment, the estimated fractional entrainment rate is much larger than those used in current convective parameterization schemes. High-resolution (100 m) large-eddy simulation of TWP-ICE convection was also analyzed to support the CRM results. It is shown that the characteristics of entrainment rates estimated using both the high-resolution data and CRM-resolution coarse-grained data are similar. For each cloud category, the entrainment rate is high near cloud base and top, but low in the middle of clouds. The entrainment rates are best fitted to the inverse of in-cloud vertical velocity by a second order polynomial.

  18. Elementary theory of bed-sediment entrainment by debris flows and avalanches

    Science.gov (United States)

    Iverson, Richard M.

    2012-01-01

    Analyses of mass and momentum exchange between a debris flow or avalanche and an underlying sediment layer aid interpretations and predictions of bed-sediment entrainment rates. A preliminary analysis assesses the behavior of a Coulomb slide block that entrains bed material as it descends a uniform slope. The analysis demonstrates that the block's momentum can grow unstably, even in the presence of limited entrainment efficiency. A more-detailed, depth-integrated continuum analysis of interacting, deformable bodies identifies mechanical controls on entrainment efficiency, and shows that entrainment rates satisfy a jump condition that involves shear-traction and velocity discontinuities at the flow-bed boundary. Explicit predictions of the entrainment rateEresult from making reasonable assumptions about flow velocity profiles and boundary shear tractions. For Coulomb-friction tractions, predicted entrainment rates are sensitive to pore fluid pressures that develop in bed sediment as it is overridden. In the simplest scenario the bed sediment liquefies completely, and the entrainment-rate equation reduces toE = 2μ1gh1 cos θ(1 − λ1)/ , where θ is the slope angle, μ1 is the flow's Coulomb friction coefficient, h1 is its thickness, λ1 is its degree of liquefaction, and is its depth-averaged velocity. For values ofλ1ranging from 0.5 to 0.8, this equation predicts entrainment rates consistent with rates of 0.05 to 0.1 m/s measured in large-scale debris-flow experiments in which wet sediment beds liquefied almost completely. The propensity for bed liquefaction depends on several factors, including sediment porosity, permeability, and thickness, and rates of compression and shear deformation that occur when beds are overridden.

  19. Neural Entrainment to the Beat: The "Missing-Pulse" Phenomenon.

    Science.gov (United States)

    Tal, Idan; Large, Edward W; Rabinovitch, Eshed; Wei, Yi; Schroeder, Charles E; Poeppel, David; Zion Golumbic, Elana

    2017-06-28

    Most humans have a near-automatic inclination to tap, clap, or move to the beat of music. The capacity to extract a periodic beat from a complex musical segment is remarkable, as it requires abstraction from the temporal structure of the stimulus. It has been suggested that nonlinear interactions in neural networks result in cortical oscillations at the beat frequency, and that such entrained oscillations give rise to the percept of a beat or a pulse. Here we tested this neural resonance theory using MEG recordings as female and male individuals listened to 30 s sequences of complex syncopated drumbeats designed so that they contain no net energy at the pulse frequency when measured using linear analysis. We analyzed the spectrum of the neural activity while listening and compared it to the modulation spectrum of the stimuli. We found enhanced neural response in the auditory cortex at the pulse frequency. We also showed phase locking at the times of the missing pulse, even though the pulse was absent from the stimulus itself. Moreover, the strength of this pulse response correlated with individuals' speed in finding the pulse of these stimuli, as tested in a follow-up session. These findings demonstrate that neural activity at the pulse frequency in the auditory cortex is internally generated rather than stimulus-driven. The current results are both consistent with neural resonance theory and with models based on nonlinear response of the brain to rhythmic stimuli. The results thus help narrow the search for valid models of beat perception.SIGNIFICANCE STATEMENT Humans perceive music as having a regular pulse marking equally spaced points in time, within which musical notes are temporally organized. Neural resonance theory (NRT) provides a theoretical model explaining how an internal periodic representation of a pulse may emerge through nonlinear coupling between oscillating neural systems. After testing key falsifiable predictions of NRT using MEG recordings, we

  20. Gas entrainment in the IHX vessel of top-entry loop-type LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Y. (FBR Development Dept., Japan Atomic Power Co., Tokyo (Japan)); Yamamoto, K. (FBR Development Dept., Japan Atomic Power Co., Tokyo (Japan)); Funada, T. (FBR Development Dept., Japan Atomic Power Co., Tokyo (Japan)); Tanaka, N. (Central Research Inst. of Electric Power Industry, Tokyo (Japan)); Moriya, S. (Central Research Inst. of Electric Power Industry, Tokyo (Japan)); Tanimoto, K. (Mitsubishi Heavy Industries Ltd., Tokyo (Japan)); Ogura, K. (Toshiba Corp., Tokyo (Japan)); Suzuki, T. (Hitachi Ltd., Tokyo (Japan)); Maekawa, I. (Kawasaki Heavy Industries Ltd., Tokyo (Japan))

    1994-02-01

    The effects of scale and fluid properties on gas entrainment onset were experimentally studied for the free surface flow in an IHX vessel of a proposed Japanese demonstration FBR. Water experiments were performed using the 1/10-th, 1/6-th, 1/3-rd and 1/1.6-th scaled models of the IHX. The experimental results indicate that the scale has a strong effect on gas entrainment onset and that the critical Fr number decreases in proportion to the -0.5-th power of the scale. Applicability of a computational method to the gas entrainment is also discussed by comparing computational and experimental results. (orig.)

  1. Prediction of amount of entrained droplets in vertical annular two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, Pravin [Purdue University, School of Nuclear Engineering, 400 Central Dr., West Lafayette, IN 47907-2017 (United States)], E-mail: psawant@purdue.edu; Ishii, Mamoru [Purdue University, School of Nuclear Engineering, 400 Central Dr., West Lafayette, IN 47907-2017 (United States)], E-mail: ishii@purdue.edu; Mori, Michitsugu [Tokyo Electric Power Co. Inc., 4-1 Egasaki-cho, Tsurumi-ku, Yokohama 230-8510 (Japan)], E-mail: michitsugu.mori@tepco.co.jp

    2009-08-15

    Prediction of amount of entrained droplets or entrainment fraction in annular two-phase flow is essential for the estimation of dryout condition and analysis of post dryout heat transfer in light water nuclear reactors and steam boilers. In this study, air-water and organic fluid (Freon-113) annular flow entrainment experiments have been carried out in 9.4 and 10.2 mm diameter test sections, respectively. Both the experiments covered three distinct pressure conditions and wide range of liquid and gas flow conditions. The organic fluid experiments simulated high pressure steam-water annular flow conditions. In each experiment, measurements of entrainment fraction, droplet entrainment rate and droplet deposition rate have been performed by using the liquid film extraction method. A simple, explicit and non-dimensional correlation developed by Sawant [Sawant, P.H., Ishii, M., Mori, M., 2008. Droplet entrainment correlation in vertical upward co-current annular two-phase flow. Nucl. Eng. Des. 238 (6), 1342-1352] for the prediction of entrainment fraction is further improved in this study in order to account for the existence of critical gas and liquid flow rates below which no entrainment is possible. Additionally, a new correlation is proposed for the estimation of minimum liquid film flow rate at the maximum entrainment fraction condition. The improved correlation successfully predicted the newly collected air-water and Freon-113 entrainment fraction data. Furthermore, the correlations satisfactorily compared with the air-water, helium-water and air-genklene experimental data measured by Willetts [Willetts, I.P., 1987. Non-aqueous annular two-phase flow. D.Phil. Thesis, University of Oxford]. However, comparison of the correlations with the steam-water data available in literature showed significant discrepancies. It is proposed that these discrepancies might have been caused due to the inadequacy of the liquid film extraction method used to measure the entrainment

  2. A model study of mixing and entrainment in the horizontally evolving atmospheric convective boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Fedorovich, E.; Kaiser, R. [Univ. Karlsruhe, Inst. fuer Hydrologie und Wasserwirtschaft (Germany)

    1997-10-01

    We present results from a parallel wind-tunnel/large-eddy simulation (LES) model study of mixing and entrainment in the atmospheric convective boundary layer (CBL) longitudinally developing over a heated surface. The advection-type entrainment of warmer air from upper turbulence-free layers into the growing CBL has been investigated. Most of numerical and laboratory model studies of the CBL carried out so far dealt with another type of entrainment, namely the non-steady one, regarding the CBL growth as a non-stationary process. In the atmosphere, both types of the CBL development can take place, often being superimposed. (au)

  3. Effects of intracerebroventricular histamine injection on circadian activity phase entrainment during rapid illumination changes.

    Science.gov (United States)

    Itowi, N; Yamatodani, A; Mochizuki, T; Wada, H

    1991-02-11

    Histamine is reported to have different effects on shifting the circadian activity phase depending on its circadian administration time (CT). The delay-sensitive period is CT 12-15, and the advance-sensitive period is CT 0-3. The activity phase of rats was entrained by a new light-dark cycle within a week in groups treated with either saline or i.c.v. histamine at CT 12-15. However, on treatment at CT 0-3 the activity phase of the group treated with histamine was entrained by the new light-dark cycle in half the period required for entrainment in the control group.

  4. Entrainment of sediment particles by retrograde vortices: Test of hypothesis using near-particle observations

    Science.gov (United States)

    Wu, Fu-Chun; Shih, Wu-Rong

    2012-09-01

    We conduct an experimental study to test the hypothesis that particle entrainment is associated with a passing retrograde vortex (spanwise vortex rotating counter to the mean shear). The pre- and post-entrainment quadrant structures are probed with the laser Doppler velocimetry (LDV) at a near-particle measurement spot, using the shifted-time cumulative quadrant fraction approach. The results are characterized by a pre-entrainment spiky rise of the Q1 fraction (outward interactions) and a mild increase of the Q4 fraction (sweeps), followed by the post-entrainment dominance of the Q4 fraction and a drastic drop of the Q1 fraction. Such results suggest that it is highly probable that particle entrainment is a result of the interactions with a passing retrograde-vortex-type coherent structure. The time series of 2-D velocities at the near-particle spot consistently exhibit the short-term peaks present at the time of entrainment. The quadrant signature at an alternative spot one grain diameter upstream of the target particle exhibits a sequence in which the pre-entrainment dominant Q1 fraction is replaced by the Q4 fraction, followed by a post-entrainment peak of the Q4 fraction. The results obtained from these two locations confirm the theoretical predictions, showing that different quadrant signatures would be detected at different spots during the passage of a retrograde vortex. We also perform an extra set of experiments, in which the target particle is set in an alternative pocket geometry with diagonal downstream valleys. The similar pre-entrainment quadrant signatures detected in all the experiments performed with different types of pocket geometry and the unique post-entrainment quadrant signature detected in those performed with the alternative pocket geometry imply that an obliquely oriented retrograde vortex may have passed, entraining the particle in diagonal directions. The results point to the potential discrepancy in the observed signatures that arises

  5. An applied model for the height of the daytime mixed layer and the entrainment zone

    DEFF Research Database (Denmark)

    Batchvarova, E.; Gryning, Sven-Erik

    1994-01-01

    -layer height: friction velocity, kinematic heat flux near the ground and potential temperature gradient in the free atmosphere above the entrainment zone. When information is available on the horizontal divergence of the large-scale flow field, the model also takes into account the effect of subsidence......A model is presented for the height of the mixed layer and the depth of the entrainment zone under near-neutral and unstable atmospheric conditions. It is based on the zero-order mixed layer height model of Batchvarova and Gryning (1991) and the parameterization of the entrainment zone depth...

  6. Application de l'Intelligence Economique dans un Système d'Information Stratégique universitaire : innovation par le processus de modélisation des acteurs

    OpenAIRE

    2006-01-01

    Nous abordons une nouvelle gouvernance des universités en empruntant le processus d'intelligence économique pour faire évoluer un système d'information universitaire en un système d'information stratégique universitaire. Par notre contribution, nous étudions les processus propres à l'organisation, les processus propres à l'enseignant et les processus propres à l'étudiant pour modéliser les utilisateurs d'un système d'information stratégique universitaire. La description des ressources documen...

  7. Contribution de l'homogénéisation à l'étude de la filtration d'un fluide en milieu poreux fracturé Contribution of the Homogenization Process to the Seepage Through Fractured Porous Media

    Directory of Open Access Journals (Sweden)

    Boutin C.

    2006-11-01

    Full Text Available Cet article est consacré à la modélisation de l'écoulement d'un fluide dans un massif poreux fracturé. Contrairement aux approches phénoménologiques, nous traitons le problème au moyen de la méthode d'homogénéisation par développements asymptotiques en milieux périodiques. Les comportements macroscopiques sont ainsi déduits de la physique à l'échelle microscopique, sans autre prérequis. Deux cas ont été examinés : l'écoulement d'un gaz dans un massif rigide et l'écoulement d'un fluide incompressible dans une matrice déformable. Dans ces deux situations, on met en évidence le rôle fondamental du rapport entre les deux séparations d'échelles (échelle macroscopique-échelle des fissures et échelle des fissures-échelle des pores. Les descriptions macroscopiques sont conditionnées par la relation entre les séparations d'échelles, le couplage interéchelle étant maximum lorsque les rapports d'échelles sont identiques. This paper deals with the seepage of a fluid through a fissured porous medium. Conversely to the phenomenological approaches we treat this problem by using the homogenization method of asymptotic developments for periodic structures. Thus the macroscopic behaviours are directly deduced from the physics at the microscopic scale, without any prerequisite. Two cases have been investigated : the flow of a gas through a rigid medium and the flow of an incompressible fluid through a deformable matrix. In both situations, it appears that the ratio between the two scale separations (macroscopic scale-fissure scale and fissure scale-pore scale plays an essential role. The macroscopic description depends on the scale separations, the interscale coupling being maximum when the scales are equally separated.

  8. Engine jet entrainment in the near field of an aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, F.; Jacquin, L.; Laverdant, A. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

    1997-12-31

    A simplified approach has been applied to analyse the mixing and entrainment processes of the engine exhaust through their interaction with the vortex wake of an aircraft. These investigations are focused on the near filed, extending from exit nozzle to the beginning of the vortex phase (i.e. to about twenty seconds after the wake is generated). This study is performed using an integral model and a numerical simulation for a two-engine large civil aircraft. The properties of the wing-tip vortices on the calculation of the dilution ratio (defined as a tracer concentration) have been shown. The mixing process is also affected by the buoyancy effect, but only after the jet regime, when the trapping in the vortex core has occurred. Qualitative comparison with contrail photography shows similar features. Finally the distortion and stretching of the plume streamlines inside the vortices can be observed, and the role of the descent of the vortices on the maximum tracer concentration has been discussed. (author) 19 refs.

  9. Changes in music tempo entrain movement related brain activity.

    Science.gov (United States)

    Daly, Ian; Hallowell, James; Hwang, Faustina; Kirke, Alexis; Malik, Asad; Roesch, Etienne; Weaver, James; Williams, Duncan; Miranda, Eduardo; Nasuto, Slawomir J

    2014-01-01

    The neural mechanisms of music listening and appreciation are not yet completely understood. Based on the apparent relationship between the beats per minute (tempo) of music and the desire to move (for example feet tapping) induced while listening to that music it is hypothesised that musical tempo may evoke movement related activity in the brain. Participants are instructed to listen, without moving, to a large range of musical pieces spanning a range of styles and tempos during an electroencephalogram (EEG) experiment. Event-related desynchronisation (ERD) in the EEG is observed to correlate significantly with the variance of the tempo of the musical stimuli. This suggests that the dynamics of the beat of the music may induce movement related brain activity in the motor cortex. Furthermore, significant correlations are observed between EEG activity in the alpha band over the motor cortex and the bandpower of the music in the same frequency band over time. This relationship is observed to correlate with the strength of the ERD, suggesting entrainment of motor cortical activity relates to increased ERD strength.

  10. Liquid Droplet Detachment and Entrainment in Microscale Flows

    Science.gov (United States)

    Hidrovo, Carlos

    2005-11-01

    In this talk we will present a first order study of liquid water detachment and entrainment into air flows in hydrophobic microchannels. Silicon based microstructures consisting of 23 mm long U-shaped channels of different geometry were used for this purpose. The structures are treated with a Molecular Vapor Deposition (MVD) process that renders them hydrophobic. Liquid water is injected through a side slot located 2/3 of the way downstream from the air channel inlet. The water entering the air channel beads up into slugs or droplets that grow in size at this injection location until they fill and flood the channel or are carried away by the air flow. The slugs/droplets dimensions at detachment are correlated against superficial gas velocity and proper dimensionless parameters are postulated and examined to compare hydrodynamic forces against surface tension. It is found that slug/droplet detachment is dominated by two main forces: pressure gradient drag, arising from confinement of a viscous flow in the channel, and inertial drag, arising from the stagnation of the air due to obstruction by the slugs/droplets. A detachment regime map is postulated based on the relative importance of these forces under different flow conditions.

  11. Entrainment, Drizzle, and the Indirect Effect in Stratiform Clouds

    Science.gov (United States)

    Ackerman, Andrew

    2005-01-01

    Activation of some fraction of increased concentrations of sub-micron soluble aerosol particles lead to enhanced cloud droplet concentrations and hence smaller droplets, increasing their total cross sectional area and thus reflecting solar radiation more efficiently (the Twomey, or first indirect, effect). However, because of competition during condensational growth, droplet distributions tend to broaden as numbers increase, reducing the sensitivity of cloud albedo to droplet concentration on the order of 10%. Also, smaller droplets less effectively produce drizzle through collisions and coalescence, and it is widely expected (and found in large-scale models) that decreased precipitation leads to clouds with more cloud water on average (the so-called cloud lifetime, or second indirect, effect). Much of the uncertainty regarding the overall indirect aerosol effect stems from inadequate understanding of such changes in cloud water. Detailed simulations based on FIRE-I, ASTEX, and DYCOMS-II conditions show that suppression of precipitation from increased droplet concentrations leads to increased cloud water only when sufficient precipitation reaches the surface, a condition favored when the overlying air is-humid or droplet concentrations are very low. Otherwise, aerosol induced suppression of precipitation enhances entrainment of overlying dry air, thereby reducing cloud water and diminishing the indirect climate forcing.

  12. Ash microstructure and formation mechanisms during entrained coal gasification

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, E.I.; Topper, U.; Kurkela, J.; Jokiniemi, J.K. [VTT Aerosol Technology Group (Finland). VTT Chemical Technology

    1998-12-01

    We have studied the structure and composition of ash particles formed during the entrained gasification of Taiheiyo coal at Nakoso IGCC pilot plant in Japan with field emission scanning and transmission electron microscopes. Ash particles can be classified into three groups based on their morphology. Particles larger than one micron are either spherical ash particles composed mainly of Al, Si Ca and O or flake-like unreacted char particles. The overall fly ash structure is dominated by agglomerates of partially sintered, 10-200 nm diameter primary particles. Primary particles are composed mainly of carbon with trace amounts of oxygen, sodium, silicon, sulphur and calcium. EDX analyses with FE-TEM show that the composition of individual primary particles varies strongly from almost pure carbon to O, Al, Si and Ca. High resolution TEM shows that carbon-rich primary particles have onion-type structure, similar to the soot structure. In addition, HR-TEM shows that the structure of primary particles varies from one to another, with some agglomerates being formed from cluster smaller than 10 nanometres in diameter. We propose ash particle formation mechanisms based on their structural and composition characterization. 5 figs.

  13. Modelling wind turbine wakes using the turbulent entrainment hypothesis

    Science.gov (United States)

    Luzzatto-Fegiz, Paolo

    2015-11-01

    Simple models for turbine wakes have been used extensively in the wind energy community, both as independent tools, as well as to complement more refined and computationally-intensive techniques. Jensen (1983; see also Katić et al. 1986) developed a model assuming that the wake radius grows linearly with distance x, approximating the velocity deficit with a top-hat profile. While this model has been widely implemented in the wind energy community, recently Bastankhah & Porté-Agel (2014) showed that it does not conserve momentum. They proposed a momentum-conserving theory, which assumed a Gaussian velocity deficit and retained the linear-spreading assumption, significantly improving agreement with experiments and LES. While the linear spreading assumption facilitates conceptual modeling, it requires empirical estimates of the spreading rate, and does not readily enable generalizations to other turbine designs. Furthermore, field measurements show sub-linear wake growth with x in the far-wake, consistently with results from fundamental turbulence studies. We develop a model by relying on a simple and general turbulence parameterization, namely the entrainment hypothesis, which has been used extensively in other areas of geophysical fluid dynamics. Without assuming similarity, we derive an analytical solution for a circular turbine wake, which predicts a far-wake radius increasing with x 1 / 3, and is consistent with field measurements and fundamental turbulence studies. Finally, we discuss developments accounting for effects of stratification, as well as generalizations to other turbine designs.

  14. Familiarity Affects Entrainment of EEG in Music Listening.

    Science.gov (United States)

    Kumagai, Yuiko; Arvaneh, Mahnaz; Tanaka, Toshihisa

    2017-01-01

    Music perception involves complex brain functions. The relationship between music and brain such as cortical entrainment to periodic tune, periodic beat, and music have been well investigated. It has also been reported that the cerebral cortex responded more strongly to the periodic rhythm of unfamiliar music than to that of familiar music. However, previous works mainly used simple and artificial auditory stimuli like pure tone or beep. It is still unclear how the brain response is influenced by the familiarity of music. To address this issue, we analyzed electroencelphalogram (EEG) to investigate the relationship between cortical response and familiarity of music using melodies produced by piano sounds as simple natural stimuli. The cross-correlation function averaged across trials, channels, and participants showed two pronounced peaks at time lags around 70 and 140 ms. At the two peaks the magnitude of the cross-correlation values were significantly larger when listening to unfamiliar and scrambled music compared to those when listening to familiar music. Our findings suggest that the response to unfamiliar music is stronger than that to familiar music. One potential application of our findings would be the discrimination of listeners' familiarity with music, which provides an important tool for assessment of brain activity.

  15. Glucocorticoids entrain molecular clock components in human peripheral cells.

    Science.gov (United States)

    Cuesta, Marc; Cermakian, Nicolas; Boivin, Diane B

    2015-04-01

    In humans, shift work induces a desynchronization between the circadian system and the outside world, which contributes to shift work-associated medical disorders. Using a simulated night shift experiment, we previously showed that 3 d of bright light at night fully synchronize the central clock to the inverted sleep schedule, whereas the peripheral clocks located in peripheral blood mononuclear cells (PBMCs) took longer to reset. This underlines the need for testing the effects of synchronizers on both the central and peripheral clocks. Glucocorticoids display circadian rhythms controlled by the central clock and are thought to act as synchronizers of rodent peripheral clocks. In the present study, we tested whether the human central and peripheral clocks were sensitive to exogenous glucocorticoids (Cortef) administered in the late afternoon. We showed that 20 mg Cortef taken orally acutely increased PER1 expression in PBMC peripheral clocks. After 6 d of Cortef administration, the phases of central markers were not affected, whereas those of PER2-3 and BMAL1 expression in PBMCs were shifted by ∼ 9.5-11.5 h. These results demonstrate, for the first time, that human peripheral clocks are entrained by glucocorticoids. Importantly, they suggest innovative interventions for shift workers and jet-lag travelers, combining synchronizing agents for the central and peripheral clocks.

  16. Fabrication de memoire monoelectronique non volatile par une approche de nanogrille flottante

    Science.gov (United States)

    Guilmain, Marc

    Les transistors monoelectroniques (SET) sont des dispositifs de tailles nanometriques qui permettent la commande d'un electron a la fois et donc, qui consomment peu d'energie. Une des applications complementaires des SET qui attire l'attention est son utilisation dans des circuits de memoire. Une memoire monoelectronique (SEM) non volatile a le potentiel d'operer a des frequences de l'ordre des gigahertz ce qui lui permettrait de remplacer en meme temps les memoires mortes de type FLASH et les memoires vives de type DRAM. Une puce SEM permettrait donc ultimement la reunification des deux grands types de memoire au sein des ordinateurs. Cette these porte sur la fabrication de memoires monoelectroniques non volatiles. Le procede de fabrication propose repose sur le procede nanodamascene developpe par C. Dubuc et al. a 1'Universite de Sherbrooke. L'un des avantages de ce procede est sa compatibilite avec le back-end-of-line (BEOL) des circuits CMOS. Ce procede a le potentiel de fabriquer plusieurs couches de circuits memoirestres denses au-dessus de tranches CMOS. Ce document presente, entre autres, la realisation d'un simulateur de memoires monoelectroniques ainsi que les resultats de simulations de differentes structures. L'optimisation du procede de fabrication de dispositifs monoelectroniques et la realisation de differentes architectures de SEM simples sont traitees. Les optimisations ont ete faites a plusieurs niveaux : l'electrolithographie, la gravure de l'oxyde, le soulevement du titane, la metallisation et la planarisation CMP. La caracterisation electrique a permis d'etudier en profondeur les dispositifs formes de jonction de Ti/TiO2 et elle a demontre que ces materiaux ne sont pas appropries. Par contre, un SET forme de jonction de TiN/Al2O3 a ete fabrique et caracterise avec succes a basse temperature. Cette demonstration demontre le potentiel du procede de fabrication et de la deposition de couche atomique (ALD) pour la fabrication de memoires

  17. ParAB Partition Dynamics in Firmicutes: Nucleoid Bound ParA Captures and Tethers ParB-Plasmid Complexes.

    Directory of Open Access Journals (Sweden)

    Virginia S Lioy

    Full Text Available In Firmicutes, small homodimeric ParA-like (δ2 and ParB-like (ω2 proteins, in concert with cis-acting plasmid-borne parS and the host chromosome, secure stable plasmid inheritance in a growing bacterial population. This study shows that (ω:YFP2 binding to parS facilitates plasmid clustering in the cytosol. (δ:GFP2 requires ATP binding but not hydrolysis to localize onto the cell's nucleoid as a fluorescent cloud. The interaction of (δ:CFP2 or δ2 bound to the nucleoid with (ω:YFP2 foci facilitates plasmid capture, from a very broad distribution, towards the nucleoid and plasmid pairing. parS-bound ω2 promotes redistribution of (δ:GFP2, leading to the dynamic release of (δ:GFP2 from the nucleoid, in a process favored by ATP hydrolysis and protein-protein interaction. (δD60A:GFP2, which binds but cannot hydrolyze ATP, also forms unstable complexes on the nucleoid. In the presence of ω2, (δD60A:GFP2 accumulates foci or patched structures on the nucleoid. We propose that (δ:GFP2 binding to different nucleoid regions and to ω2-parS might generate (δ:GFP2 gradients that could direct plasmid movement. The iterative pairing and unpairing cycles may tether plasmids equidistantly on the nucleoid to ensure faithful plasmid segregation by a mechanism compatible with the diffusion-ratchet mechanism as proposed from in vitro reconstituted systems.

  18. Hématome vulvaire massif du post-partum: à propos d'un cas à l'Hôpital Central de Yaoundé (Cameroun)

    Science.gov (United States)

    Fouelifack, Florent Ymele; Fouogue, Jovanny Tsuala; Fouedjio, Jeanne Hortence; Sando, Zacharie; Mbu, Robinson Enow

    2014-01-01

    Les hématomes puerpéraux sont une cause rare d'hémorragie du post partum. Leur prise en charge adéquate nécessite une compétence et un plateau technique particulier. A notre connaissance, aucun cas n'a été publié au Cameroun. Nous rapportons le cas d'une femme de 37 ans, G3P2013, référée d'un dispensaire vers la maternité de l'hôpital Central de Yaoundé, en état de choc hémorragique survenu une heure après un accouchement facilité par des manœuvres digitales de dilatation vaginale. Elle a été prise en charge chirurgicalement pour un hématome vulvaire expansif. Ce cas nous permet d'attirer l'attention des praticiens sur la gravité et la singularité de cette pathologie hautement morbide qui pourrait être due à des manœuvres de dilatation digitale du vagin pendant le travail. PMID:25810803

  19. Génération de faisceaux EPR à l'aide d'un oscillateur paramétrique optique à auto-verrouillage de phase

    Science.gov (United States)

    Laurat, J.; Longchambon, L.; Coudreau, T.; Fabre, C.

    2004-11-01

    Les faisceaux continus orthogonalement polarisés émis par les Oscillateurs Paramétriques Optiques (OPO) de type II pompés au-dessus du seuil présentent au niveau quantique de fortes corrélations d'intensité et anti-corrélations de phase. Ils sont donc de très bons candidats pour générer des faisceaux intriqués en quadrature. Cependant, un phénomène de diffusion de phase rend difficile la mesure des propriétés sur la phase. Nous avons étudié théoriquement le régime stationnaire et les propriétés quantiques d'un OPO contenant une lame biréfringente. Le couplage linéaire qui en résulte entraîne un verrouillage en phase ainsi qu'un fonctionnement à dégénérescence en fréquence à l'intérieur d'une zone d'accrochage. L'expérience en cours au laboratoire a permis d'observer ce phénomène de verrouillage.

  20. A Lagrangian, small-scale investigation of turbulent entrainment in an axisymmetric jet

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, M; Luethi, B; Krug, D [Institute of Environmental Engineering, ETH Zurich, 8093 Zurich (Switzerland); Holzner, M [Max Planck Institute for Dynamics and Self-Organisation, 37073 Goettingen (Germany); Liberzon, A; Tsinober, A, E-mail: wolf@ifu.baug.ethz.ch [School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2011-12-22

    Particle tracking velocimetry (PTV) was applied to study turbulent entrainment in an axisymmetric jet at Re = 5000. Several single-point flow statistics are used to characterize the general flow field of our newly designed jet facility, proving that a self-preserving axisymmetric jet could be established. An analysis of the Lagrangian evolution of small scale quantities, such as vorticity and strain, along trajectories passing the entrainment interface is performed. We find that a particle needs on the order of one Kolmogorov time scale to cross the entrainment interface, which is similar to results of grid turbulence without mean shear. Finally, we perform a conditional investigation of invariants of du{sub i}/du{sub j} at the entrainment interface, analyzing joint probability density functions (joint PDFs) evaluated at different times along trajectories crossing the interfacial region.

  1. A Lagrangian, small-scale investigation of turbulent entrainment in an axisymmetric jet

    Science.gov (United States)

    Wolf, M.; Lüthi, B.; Holzner, M.; Liberzon, A.; Krug, D.; Tsinober, A.

    2011-12-01

    Particle tracking velocimetry (PTV) was applied to study turbulent entrainment in an axisymmetric jet at Re = 5000. Several single-point flow statistics are used to characterize the general flow field of our newly designed jet facility, proving that a self-preserving axisymmetric jet could be established. An analysis of the Lagrangian evolution of small scale quantities, such as vorticity and strain, along trajectories passing the entrainment interface is performed. We find that a particle needs on the order of one Kolmogorov time scale to cross the entrainment interface, which is similar to results of grid turbulence without mean shear. Finally, we perform a conditional investigation of invariants of at the entrainment interface, analyzing joint probability density functions (joint PDFs) evaluated at different times along trajectories crossing the interfacial region.

  2. Miniature Sample Collection and Delivery System using Gas-Entrained Powder Transport Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a miniature system for acquisition and delivery of solid samples to landed planetary instruments. This system would entrain powder produced by...

  3. REGSOLexpert: Entrainer Selection Tool for waste solvent recovery by batch distillation processes

    OpenAIRE

    Rodriguez-Donis, Ivonne; Gerbaud, Vincent; Baudouin, Olivier; Joulia, Xavier

    2009-01-01

    A general procedure to systematize the search of several alternatives enabling the separation of non-ideal binary mixtures such as pressure-swing distillation, azeotropic and extractive distillation is presented. The use of heterogeneous entrainers is specially highlighted.

  4. Theory of wetting-induced fluid entrainment by advancing contact lines on dry surfaces.

    Science.gov (United States)

    Ledesma-Aguilar, R; Hernández-Machado, A; Pagonabarraga, I

    2013-06-28

    We report on the onset of fluid entrainment when a contact line is forced to advance over a dry solid of arbitrary wettability. We show that entrainment occurs at a critical advancing speed beyond which the balance between capillary, viscous, and contact-line forces sustaining the shape of the interface is no longer satisfied. Wetting couples to the hydrodynamics by setting both the morphology of the interface at small scales and the viscous friction of the front. We find that the critical deformation that the interface can sustain is controlled by the friction at the contact line and the viscosity contrast between the displacing and displaced fluids, leading to a rich variety of wetting-entrainment regimes. We discuss the potential use of our theory to measure contact-line forces using atomic force microscopy and to study entrainment under microfluidic conditions exploiting colloid-polymer fluids of ultralow surface tension.

  5. Speech entrainment enables patients with Broca's aphasia to produce fluent speech.

    Science.gov (United States)

    Fridriksson, Julius; Hubbard, H Isabel; Hudspeth, Sarah Grace; Holland, Audrey L; Bonilha, Leonardo; Fromm, Davida; Rorden, Chris

    2012-12-01

    A distinguishing feature of Broca's aphasia is non-fluent halting speech typically involving one to three words per utterance. Yet, despite such profound impairments, some patients can mimic audio-visual speech stimuli enabling them to produce fluent speech in real time. We call this effect 'speech entrainment' and reveal its neural mechanism as well as explore its usefulness as a treatment for speech production in Broca's aphasia. In Experiment 1, 13 patients with Broca's aphasia were tested in three conditions: (i) speech entrainment with audio-visual feedback where they attempted to mimic a speaker whose mouth was seen on an iPod screen; (ii) speech entrainment with audio-only feedback where patients mimicked heard speech; and (iii) spontaneous speech where patients spoke freely about assigned topics. The patients produced a greater variety of words using audio-visual feedback compared with audio-only feedback and spontaneous speech. No difference was found between audio-only feedback and spontaneous speech. In Experiment 2, 10 of the 13 patients included in Experiment 1 and 20 control subjects underwent functional magnetic resonance imaging to determine the neural mechanism that supports speech entrainment. Group results with patients and controls revealed greater bilateral cortical activation for speech produced during speech entrainment compared with spontaneous speech at the junction of the anterior insula and Brodmann area 47, in Brodmann area 37, and unilaterally in the left middle temporal gyrus and the dorsal portion of Broca's area. Probabilistic white matter tracts constructed for these regions in the normal subjects revealed a structural network connected via the corpus callosum and ventral fibres through the extreme capsule. Unilateral areas were connected via the arcuate fasciculus. In Experiment 3, all patients included in Experiment 1 participated in a 6-week treatment phase using speech entrainment to improve speech production. Behavioural and

  6. ¡París!

    Directory of Open Access Journals (Sweden)

    Beatriz Caballero

    2003-01-01

    Full Text Available El día no le alcanzaba para caminarlo. Conocía cada puente, cada calle,plaza, museo, rincón, iglesia, café, y la mesa con el mejor ángulo para mirar siempre una iglesia, ojalá Saint-Germain-des-Pres, o Notre-Dame. Siempre contaba la impresión que le había causado a Bolívar ver allí cuando el papa coronó a Napoleón. Él se iba para la oficina todos los días, Luis a un taller a pintar, Antonio a estudiar ciencias políticas, yo al colegio y mamá hacía las cosas prácticas. Aprendíamos francés todos al tiempo y por la noche nos contábamos lo nuevo que cada uno había aprendido. Mamá después, cuando ya se quería volver, decía que París nos había maleado a todos. Estaba en pleno furor el cine francés de la "nueva ola", pero ella sólo me llevaba a ver películas de vaqueros pues no se fiaba de la clasificación de los periódicos.

  7. Donovanose no Pará

    Directory of Open Access Journals (Sweden)

    Domingos Silva

    1991-12-01

    Full Text Available Foram estudados 259 casos de donovanose registrados no Serviço de Dermatologia do Departamento de Medicina Tropical/UFPA entre 1954-1990. Observa-se que no período 1954-1974 existiam nos arquivos apenas 56 prontuários da doença, enquanto que no último quinquénio estudado (1986-1990 foram identificados 133 casos. Para os autores esse crescimento está ligado a excessiva liberalidade sexual, ao homossexualismo e as precárias condições sócio-econômicas, acentuada nos últimos tempos.From 1954 to 1990 granuloma inguinale was diagnosed in 259 patients al the dermatology service of the Universidade Federal do Pará in Belém, Brazil. Among them, 56 cases had ocurred in the twenty-year period 1954-1974 and as many as 133 cases were seen during the last five years only. Greater sexual liberty, poor social and economic conditions, and especially increasing homosexual behavior were implicated by the authors as chief determinants for this augmented incidence of the disease.

  8. Neural entrainment to rhythmically presented auditory, visual, and audio-visual speech in children.

    Science.gov (United States)

    Power, Alan James; Mead, Natasha; Barnes, Lisa; Goswami, Usha

    2012-01-01

    Auditory cortical oscillations have been proposed to play an important role in speech perception. It is suggested that the brain may take temporal "samples" of information from the speech stream at different rates, phase resetting ongoing oscillations so that they are aligned with similar frequency bands in the input ("phase locking"). Information from these frequency bands is then bound together for speech perception. To date, there are no explorations of neural phase locking and entrainment to speech input in children. However, it is clear from studies of language acquisition that infants use both visual speech information and auditory speech information in learning. In order to study neural entrainment to speech in typically developing children, we use a rhythmic entrainment paradigm (underlying 2 Hz or delta rate) based on repetition of the syllable "ba," presented in either the auditory modality alone, the visual modality alone, or as auditory-visual speech (via a "talking head"). To ensure attention to the task, children aged 13 years were asked to press a button as fast as possible when the "ba" stimulus violated the rhythm for each stream type. Rhythmic violation depended on delaying the occurrence of a "ba" in the isochronous stream. Neural entrainment was demonstrated for all stream types, and individual differences in standardized measures of language processing were related to auditory entrainment at the theta rate. Further, there was significant modulation of the preferred phase of auditory entrainment in the theta band when visual speech cues were present, indicating cross-modal phase resetting. The rhythmic entrainment paradigm developed here offers a method for exploring individual differences in oscillatory phase locking during development. In particular, a method for assessing neural entrainment and cross-modal phase resetting would be useful for exploring developmental learning difficulties thought to involve temporal sampling, such as

  9. Experimental Determination of Load Carrying Capacity of Point Contacts at Zero Entrainment Velocity

    Science.gov (United States)

    Shogrin, Bradley A.; Jones, William R., Jr.; Kingsbury, Edward P.; Prahl, Joseph M.

    1999-01-01

    A capacitance technique was used to monitor the film thickness separating two steel balls of a unique tribometer while subjecting the ball-ball contact to highly stressed, zero entrainment velocity (ZEV) conditions. All tests were performed under a N2 purge (R.H. carrying capacity at these zero entrainment velocity conditions, relevant to the ball-ball contact application in retainerless ball bearings.

  10. Food-entrained feeding and locomotor circadian rhythms in rats under different lighting conditions.

    Science.gov (United States)

    Lax, P; Zamora, S; Madrid, J A

    1999-05-01

    It has been suggested that two endogenous timekeeping systems, a light-entrainable pacemaker (LEP) and a food-entrainable pacemaker (FEP), control circadian rhythms. To understand the function and interaction between these two mechanisms better, we studied two behavioral circadian rhythmicities, feeding and locomotor activity, in rats exposed to two conflicting zeitgebers, food restriction and light-dark cycles. For this, the food approaches and wheel-running activity of rats kept under light-dark (LD) 12:12, constant darkness (DD), or constant light (LL) conditions and subjected to different scheduled feeding patterns were continuously recorded. To facilitate comparison of the results obtained under the different lighting conditions, the period of the feeding cycles was set in all three cases about 1h less than the light-entrained or free-running circadian rhythms. The results showed that, depending on the lighting conditions, some components of the feeding and wheel-running circadian rhythms could be entrained by food pulses, while others retained their free-running or light-entrained state. Under LD, food pulses had little influence on the light-entrained feeding and locomotor rhythms. Under DD, relative coordination between free-running and food-associated rhythms may appear. In both cases, the feeding activity associated with the food pulses could be divided into a prominent phase-dependent peak of activity within the period of food availability and another afterward. Wheel-running activity mainly followed the food pulses. Under LL conditions, the food-entrained activity consisted mainly of feeding and wheel-running anticipatory activity. The results provide new evidence that lighting conditions influence the establishment and persistence of food-entrained circadian rhythms in rats. The existence of two coupled pacemakers, LEP and FEP, or a multioscillatory LEP may both explain our experimental results.

  11. Complex Patterns of Metabolic and Ca2+ Entrainment in Pancreatic Islets by Oscillatory Glucose

    OpenAIRE

    Pedersen, Morten Gram; Mosekilde, Erik; Polonsky, Kenneth S.; Luciani, Dan S.

    2013-01-01

    Glucose-stimulated insulin secretion is pulsatile and driven by intrinsic oscillations in metabolism, electrical activity, and Ca2+ in pancreatic islets. Periodic variations in glucose can entrain islet Ca2+ and insulin secretion, possibly promoting interislet synchronization. Here, we used fluorescence microscopy to demonstrate that glucose oscillations can induce distinct 1:1 and 1:2 entrainment of oscillations (one and two oscillations for each period of exogenous stimulus, respectively) i...

  12. Neural entrainment to rhythmically-presented auditory, visual and audio-visual speech in children

    Directory of Open Access Journals (Sweden)

    Alan James Power

    2012-07-01

    Full Text Available Auditory cortical oscillations have been proposed to play an important role in speech perception. It is suggested that the brain may take temporal ‘samples’ of information from the speech stream at different rates, phase-resetting ongoing oscillations so that they are aligned with similar frequency bands in the input (‘phase locking’. Information from these frequency bands is then bound together for speech perception. To date, there are no explorations of neural phase-locking and entrainment to speech input in children. However, it is clear from studies of language acquisition that infants use both visual speech information and auditory speech information in learning. In order to study neural entrainment to speech in typically-developing children, we use a rhythmic entrainment paradigm (underlying 2 Hz or delta rate based on repetition of the syllable ba, presented in either the auditory modality alone, the visual modality alone, or as auditory-visual speech (via a talking head. To ensure attention to the task, children aged 13 years were asked to press a button as fast as possible when the ba stimulus violated the rhythm for each stream type. Rhythmic violation depended on delaying the occurrence of a ba in the isochronous stream. Neural entrainment was demonstrated for all stream types, and individual differences in standardized measures of language processing were related to auditory entrainment at the theta rate. Further, there was significant modulation of the preferred phase of auditory entrainment in the theta band when visual speech cues were present, indicating cross-modal phase resetting. The rhythmic entrainment paradigm developed here offers a method for exploring individual differences in oscillatory phase locking during development. In particular, a method for assessing neural entrainment and cross-modal phase resetting would be useful for exploring developmental learning difficulties thought to involve temporal sampling

  13. L'utopie de l'espace artistique et social: transformer les consciences par l'art

    Directory of Open Access Journals (Sweden)

    Orazio Maria Valastro

    2012-12-01

    Full Text Available J'ai rencontré Antonio Presti, président de la Fondation Fiumara d'Arte, pendant l'été 2011 à l'Art Hotel - Atelier sur mer, situé à Castel di Tusa dans la province de Messina. Notre entretien s'est déroulé devant la mer de la côte nord occidentale de la Sicile. Nous avons discuté des projets et des activités de la Fondation au service de l'utopie : donner corps à l'utopie moyennant l'art pour éduquer la communauté à la beauté, cette utopie qui prend corps depuis 1982 en Sicile, pour la transmettre comme futur à un réseaux d'utopistes et aux prochaines générations. Discours et pratiques de l'utopie relèvent ici d'un dénominateur commun recouvrant un élément thématique transversal, l'expérience émotionnelle du voyage comme purification par le rêve de l'art en terme de valeurs éthiques. L'éducation par l'esthétique dans la jouissance de l'œuvre d'art rétablit une pédagogie symbolique, éduquant par l'art à l'énergie universelle représentée par la dévotion à la beauté : inspiration à un faire utopique vivifiant un nouvel état social et culturel s'opposant au néant qui travaille cette société, consumériste et matérialiste, par l'accompagnement symbolique des rites de la lumière hélant l'accès au régions de la connaissance spirituelle. Quelles sont ainsi les caractéristiques du discours et de la praxis utopique faisant l'objet de notre réflexion autour des utopies contemporaines ? Ce n'est que par une analyse des marqueurs spécifiques de l'utopie, les trais communs dégagés par Lucien Sfez structurant la condition nécessaire de toute analyse portant sur les utopies, que allons saisir les discours et les activités de la Fondation Fiumara d'Arte.

  14. Epidémiologie du cancer gastrique: expérience d'un centre hospitalier marocain

    Science.gov (United States)

    Mellouki, Ihsane; laazar, Nawal; Benyachou, Bahija; Aqodad, Nouredine; Ibrahimi, Adil

    2014-01-01

    Le cancer de l'estomac est représenté essentiellement par Les adénocarcinomes gastriques, ces derniers demeurent l'une des dix premières causes mondiales de mortalité avec un pronostic qui est péjoratif. Son incidence reste variable à travers le monde, elle est caractérisée par une importante disparité géographique. Le but de notre travail est de décrire les caractéristiques épidémiologiques de l'adénocarcinome gastrique dans notre contexte à travers une étude rétrospective, observationnelle étalée sur une période de 10 ans (Janvier 2001- Janvier 2011), incluant tous les malades admis au service d'hépato-gastroentérologie du CHU Hassan II de Fès pour prise en charge d'un adénocarcinome gastrique. Durant cette période, 343 patients étaient admis pour prise en charge d'une tumeur gastrique, dont 170 patients avaient un adénocarcinome gastrique (49.5%). L’âge moyen de ces patients était de 58±13.4 ans [16 ans-0 ans]. Dans 43.7% des cas, les patients provenaient de la région de Fès, souvent du milieu rurale. On note une nette prédominance masculine, avec une différence significative entre les 2 sexes (p gastrique (p = 0.02). la non consommation de l'alcool est inversement liée et de façon significative à l'apparition de l'adénocarcinome gastrique (p = 0.03) dans notre contexte. L'infection par Hélicobacter pylori n’était mentionnée que chez peu de malades. Les formes métastatiques au moment du diagnostic dépassaient 50% avec un taux de décès au cours de l'hospitalisation de 2.6%. Sur le plan endoscopique, la localisation antropylorique, et la forme ulcéro-végétante étaient prédominantes, elles présentaient successivement 49% (p = 0,002) et 66% (p = 0.00001). Une chirurgie curative n’était proposée que chez 50 patients (30.2%). L'adénocarcinome gastrique représente le type histologique le plus fréquent, son pronostic reste fâcheux dans notre région, touchant une population jeune, minimisant ainsi les

  15. Are non-human primates capable of rhythmic entrainment? Evidence for the gradual audiomotor evolution hypothesis.

    Science.gov (United States)

    Merchant, Hugo; Honing, Henkjan

    2013-01-01

    We propose a decomposition of the neurocognitive mechanisms that might underlie interval-based timing and rhythmic entrainment. Next to reviewing the concepts central to the definition of rhythmic entrainment, we discuss recent studies that suggest rhythmic entrainment to be specific to humans and a selected group of bird species, but, surprisingly, is not obvious in non-human primates. On the basis of these studies we propose the gradual audiomotor evolution hypothesis that suggests that humans fully share interval-based timing with other primates, but only partially share the ability of rhythmic entrainment (or beat-based timing). This hypothesis accommodates the fact that non-human primates (i.e., macaques) performance is comparable to humans in single interval tasks (such as interval reproduction, categorization, and interception), but show differences in multiple interval tasks (such as rhythmic entrainment, synchronization, and continuation). Furthermore, it is in line with the observation that macaques can, apparently, synchronize in the visual domain, but show less sensitivity in the auditory domain. And finally, while macaques are sensitive to interval-based timing and rhythmic grouping, the absence of a strong coupling between the auditory and motor system of non-human primates might be the reason why macaques cannot rhythmically entrain in the way humans do.

  16. Small scale processes and entrainment in a stratocumulus marine boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, D.E.; Almgren, A.S.; Bell, J.B.; Beckner, V.E.; Rendleman, C.A.

    1998-05-01

    Lack of resolution is a common problem hampering the use of large eddy simulation models for investigating boundary layer dynamics. Entrainment into the tops of marine stratus is characteristic of this problem. The use of parallel computing as a technique for resolving both boundary layer motions and the entrainment region enables the investigation of the interaction between the moist thermodynamics and turbulence in the entrainment region at very small length scales (dx = 8 m, dz = 4 m). This interaction results in heterogeneity at small scales which is important for correctly diagnosing the details of entrainment. This study presents several numerical experiments at high resolution using a generalization of a 1995 GCSS (GEWEX Cloud System Studies) model intercomparison. Subtle details of the numerical algorithm are found to cause larger differences in entrainment than choice of subgrid model. A kinetic energy budget shows that even for very high resolution, numerical dissipation is usually larger than that produced by the subgrid model. However, the structure of eddies at the inversion is determined mainly by resolution with very little dependence on numerical representation. Inversion properties are converging as resolution approaches an undulation scale. Most of the mixing is confined within 100 meters of the inversion with entraining motions having an aspect ratio of 6 to 1.

  17. The role of the endocrine system in feeding-induced tissue-specific circadian entrainment.

    Science.gov (United States)

    Sato, Miho; Murakami, Mariko; Node, Koichi; Matsumura, Ritsuko; Akashi, Makoto

    2014-07-24

    The circadian clock is entrained to environmental cycles by external cue-mediated phase adjustment. Although the light input pathway has been well defined, the mechanism of feeding-induced phase resetting remains unclear. The tissue-specific sensitivity of peripheral entrainment to feeding suggests the involvement of multiple pathways, including humoral and neuronal signals. Previous in vitro studies with cultured cells indicate that endocrine factors may function as entrainment cues for peripheral clocks. However, blood-borne factors that are well characterized in actual feeding-induced resetting have yet to be identified. Here, we report that insulin may be involved in feeding-induced tissue-type-dependent entrainment in vivo. In ex vivo culture experiments, insulin-induced phase shift in peripheral clocks was dependent on tissue type, which was consistent with tissue-specific insulin sensitivity, and peripheral entrainment in insulin-sensitive tissues involved PI3K- and MAPK-mediated signaling pathways. These results suggest that insulin may be an immediate early factor in feeding-mediated tissue-specific entrainment.

  18. The Role of the Endocrine System in Feeding-Induced Tissue-Specific Circadian Entrainment

    Directory of Open Access Journals (Sweden)

    Miho Sato

    2014-07-01

    Full Text Available The circadian clock is entrained to environmental cycles by external cue-mediated phase adjustment. Although the light input pathway has been well defined, the mechanism of feeding-induced phase resetting remains unclear. The tissue-specific sensitivity of peripheral entrainment to feeding suggests the involvement of multiple pathways, including humoral and neuronal signals. Previous in vitro studies with cultured cells indicate that endocrine factors may function as entrainment cues for peripheral clocks. However, blood-borne factors that are well characterized in actual feeding-induced resetting have yet to be identified. Here, we report that insulin may be involved in feeding-induced tissue-type-dependent entrainment in vivo. In ex vivo culture experiments, insulin-induced phase shift in peripheral clocks was dependent on tissue type, which was consistent with tissue-specific insulin sensitivity, and peripheral entrainment in insulin-sensitive tissues involved PI3K- and MAPK-mediated signaling pathways. These results suggest that insulin may be an immediate early factor in feeding-mediated tissue-specific entrainment.

  19. Atrophie cérébrale diffuse au cours d'un syndrome de Goldenhar: à propos d'un cas

    Science.gov (United States)

    Asani, Yogolelo; Mulenga, Cilundika; Ngombe, Léon Kabamba; Mbuyi-Musansayi; Muenze, Kalenga; Borasisi, Chenge; Speeg-Schatz

    2014-01-01

    Les auteurs rapportent un cas d'un syndrome de Goldenhar non décris dans la littérature chez un nourrisson de 3 mois, de sexe féminin présentant une atrophie cérébrale diffuse. Cette observation permet de décrire cette malformation rare et d'attirer l'attention de l'opinion scientifique à mettre en marche des études poussées afin de comprendre la survenue de cette pathologie. PMID:25767659

  20. Occlusion intestinale aigue révélant un lymphome T digestif associé à la maladie cœliaque, à propos d'un cas

    Science.gov (United States)

    Garba, Abdoul Aziz; Adamou, Harissou; Magagi, Ibrahim Amadou; Brah, Souleymane; Habou, Oumarou

    2016-01-01

    Le lymphome T intestinal associé à une entéropathie ou Enteropathy associated T-cell lymphoma (EATL), est une complication rare de la maladie cœliaque (MC). Nous rapportons l'observation d'un lymphome T associée à une MC révélé par une occlusion intestinale aigue. Une patiente maghrébine de 38 ans, aux antécédents de stérilité et de douleurs abdominales chroniques, était admise en urgence pour occlusion intestinale aigue. L'intervention chirurgicale retrouvait une tumeur au dépend du grêle avec des adénopathies mésentériques. L'histologie et l'immunohistochimie de la pièce opératoire objectivait un lymphome T digestif CD3+ et le bilan immunologique de la maladie cœliaque était positif. Le diagnostic d'EATL était ainsi retenu. La patiente était mise sous chimiothérapie (CHOEP) et régime sans gluten avec une réponse complète au traitement. L'EATL est une complication rare de la MC qui peut être révélée par une occlusion intestinale. Son pronostic peut être amélioré par une prise en charge précoce associant chirurgie et chimiothérapie. Sa prévention passe par un diagnostic précoce de la MC et un régime sans gluten. PMID:27217874

  1. Study on Turbulent Modeling in Gas Entrainment Evaluation Method

    Science.gov (United States)

    Ito, Kei; Ohshima, Hiroyuki; Nakamine, Yoshiaki; Imai, Yasutomo

    Suppression of gas entrainment (GE) phenomena caused by free surface vortices are very important to establish an economically superior design of the sodium-cooled fast reactor in Japan (JSFR). However, due to the non-linearity and/or locality of the GE phenomena, it is not easy to evaluate the occurrences of the GE phenomena accurately. In other words, the onset condition of the GE phenomena in the JSFR is not predicted easily based on scaled-model and/or partial-model experiments. Therefore, the authors are developing a CFD-based evaluation method in which the non-linearity and locality of the GE phenomena can be considered. In the evaluation method, macroscopic vortex parameters, e.g. circulation, are determined by three-dimensional CFD and then, GE-related parameters, e.g. gas core (GC) length, are calculated by using the Burgers vortex model. This procedure is efficient to evaluate the GE phenomena in the JSFR. However, it is well known that the Burgers vortex model tends to overestimate the GC length due to the lack of considerations on some physical mechanisms. Therefore, in this study, the authors develop a turbulent vortex model to evaluate the GE phenomena more accurately. Then, the improved GE evaluation method with the turbulent viscosity model is validated by analyzing the GC lengths observed in a simple experiment. The evaluation results show that the GC lengths analyzed by the improved method are shorter in comparison to the original method, and give better agreement with the experimental data.

  2. Empathy, engagement, entrainment: the interaction dynamics of aesthetic experience.

    Science.gov (United States)

    Brinck, Ingar

    2017-04-08

    A recent version of the view that aesthetic experience is based in empathy as inner imitation explains aesthetic experience as the automatic simulation of actions, emotions, and bodily sensations depicted in an artwork by motor neurons in the brain. Criticizing the simulation theory for committing to an erroneous concept of empathy and failing to distinguish regular from aesthetic experiences of art, I advance an alternative, dynamic approach and claim that aesthetic experience is enacted and skillful, based in the recognition of others' experiences as distinct from one's own. In combining insights from mainly psychology, phenomenology, and cognitive science, the dynamic approach aims to explain the emergence of aesthetic experience in terms of the reciprocal interaction between viewer and artwork. I argue that aesthetic experience emerges by participatory sense-making and revolves around movement as a means for creating meaning. While entrainment merely plays a preparatory part in this, aesthetic engagement constitutes the phenomenological side of coupling to an artwork and provides the context for exploration, and eventually for moving, seeing, and feeling with art. I submit that aesthetic experience emerges from bodily and emotional engagement with works of art via the complementary processes of the perception-action and motion-emotion loops. The former involves the embodied visual exploration of an artwork in physical space, and progressively structures and organizes visual experience by way of perceptual feedback from body movements made in response to the artwork. The latter concerns the movement qualities and shapes of implicit and explicit bodily responses to an artwork that cue emotion and thereby modulate over-all affect and attitude. The two processes cause the viewer to bodily and emotionally move with and be moved by individual works of art, and consequently to recognize another psychological orientation than her own, which explains how art can cause

  3. Integration et evaluation de capacites interactives d'un robot humanoide

    Science.gov (United States)

    Rosseau, Vincent

    'intégration de l'ensemble de ces modalités devrait améliorer la capacité du robot à engager des personnes à interagir avec lui. Des expérimentations ont été faites en milieu contrôlé et non-contrôlé selon deux protocoles expérimentaux : une étude des modalités à l'intérieur d'une population, et une étude de variation entre individus. D'une manière générale, il en ressort que l'ajout de modalités améliore la qualité de l'engagement de l'interaction par le robot, mais qu'il faut porter une attention particulière à l'approche de la personne par le robot, principalement pour les personnes non familières avec ce dernier. De plus, les observations indiquent qu'il est plus facile d'obtenir des résultats significatifs en environnement contrôlé, elles permettent d'identifier des pistes d'amélioration pour éventuellement arriver à en obtenir en milieu non-contrôlé. Enfin, ce premier projet d'intégration et d'évaluation de capacités interactives d'un robot mobile servira à alimenter une prochaine itération avec un robot plus sophistiqué présentement en conception. Mots-clés : interaction humain-robot, interruption, robot mobile autonome, multiples modalités d'interaction.

  4. Die konstellasie taalbegrip-logika in die Middeleeuse filosofie (2: Duns Skotus tot De Rivo

    Directory of Open Access Journals (Sweden)

    Johann Beukes

    2012-01-01

    Full Text Available The constellation language-logic in medieval philosophy (2: Duns Scotus to De Rivo. This second in a series of two articles continues the attempt to provide an in-depth overview of some of the most prominent – and some of the most underpublished - medieval thinkers’ stances on the constellation of language and logic, thus as a combined and condensed problem in western philosophy between the 5th and 15th centuries. The two articles form part of a rehabilitating series of modern-critical articles on understated and marginalised themes, texts and figures in medieval philosophy. The positions of the well-known philosophers that are covered in the two articles, St Augustine, Peter Abelard, St Thomas Aquinas, John Duns Scotus and William of Ockham, are juxtaposed with some less familiar philosophical positions, amongst others those of Boethius, Peter of Spain, John Wyclif and Peter de Rivo.

  5. Complex patterns of metabolic and Ca²⁺ entrainment in pancreatic islets by oscillatory glucose.

    Science.gov (United States)

    Pedersen, Morten Gram; Mosekilde, Erik; Polonsky, Kenneth S; Luciani, Dan S

    2013-07-02

    Glucose-stimulated insulin secretion is pulsatile and driven by intrinsic oscillations in metabolism, electrical activity, and Ca(2+) in pancreatic islets. Periodic variations in glucose can entrain islet Ca(2+) and insulin secretion, possibly promoting interislet synchronization. Here, we used fluorescence microscopy to demonstrate that glucose oscillations can induce distinct 1:1 and 1:2 entrainment of oscillations (one and two oscillations for each period of exogenous stimulus, respectively) in islet Ca(2+), NAD(P)H, and mitochondrial membrane potential. To our knowledge, this is the first demonstration of metabolic entrainment in islets, and we found that entrainment of metabolic oscillations requires voltage-gated Ca(2+) influx. We identified diverse patterns of 1:2 entrainment and showed that islet synchronization during entrainment involves adjustments of both oscillatory phase and period. All experimental findings could be recapitulated by our recently developed mathematical model, and simulations suggested that interislet variability in 1:2 entrainment patterns reflects differences in their glucose sensitivity. Finally, our simulations and recordings showed that a heterogeneous group of islets synchronized during 1:2 entrainment, resulting in a clear oscillatory response from the collective. In summary, we demonstrate that oscillatory glucose can induce complex modes of entrainment of metabolically driven oscillations in islets, and provide additional support for the notion that entrainment promotes interislet synchrony in the pancreas.

  6. Doing Duo – a case study of entrainment in William Forsythe’s choreography “Duo”

    Science.gov (United States)

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E.

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe’s choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models. PMID:25374522

  7. Pars Plana Vitrectomy in Advanced Coats’ Disease

    OpenAIRE

    Gulipek Muftuoglu; Gokhan Gulkilik

    2011-01-01

    Purpose: To report 5 cases of advanced Coats’ disease managed with pars plana vitrectomy and silicone oil tamponade. Methods: Five patients with advanced Coats’ disease and serous or tractional retinal detachment underwent pars plana vitrectomy with internal drainage, endolaser photocoagulation and silicone oil tamponade. One patient had combined phacoemulsification-vitrectomy surgery. Of the 5 patients, 1 had intravitreal hemorrhage and a retinal macrocyst and 1 had a retinal cyst. Follow-up...

  8. Dunning-Kruger effects in reasoning: Theoretical implications of the failure to recognize incompetence.

    Science.gov (United States)

    Pennycook, Gordon; Ross, Robert M; Koehler, Derek J; Fugelsang, Jonathan A

    2017-02-21

    The Dunning-Kruger effect refers to the observation that the incompetent are often ill-suited to recognize their incompetence. Here we investigated potential Dunning-Kruger effects in high-level reasoning and, in particular, focused on the relative effectiveness of metacognitive monitoring among particularly biased reasoners. Participants who made the greatest numbers of errors on the cognitive reflection test (CRT) overestimated their performance on this test by a factor of more than 3. Overestimation decreased as CRT performance increased, and those who scored particularly high underestimated their performance. Evidence for this type of systematic miscalibration was also found on a self-report measure of analytic-thinking disposition. Namely, genuinely nonanalytic participants (on the basis of CRT performance) overreported their "need for cognition" (NC), indicating that they were dispositionally analytic when their objective performance indicated otherwise. Furthermore, estimated CRT performance was just as strong a predictor of NC as was actual CRT performance. Our results provide evidence for Dunning-Kruger effects both in estimated performance on the CRT and in self-reported analytic-thinking disposition. These findings indicate that part of the reason why people are biased is that they are either unaware of or indifferent to their own bias.

  9. C9.A/14 steelwork joints de poutres par plaque frontale : assemblages par gousset

    CERN Document Server

    2015-01-01

    Les Tables de résistances ultimes des assemblages boulonnés par plaque frontale et par gousset, complétées par une description des modèles de calcul et des exemples d’application, ont pour but de faciliter la tâche de l'ingénieur et du constructeur. Cette première partie C9.A/14 contient les chapitres suivants: - Joints de poutres par plaque frontale en acier S235 et S355 - Assemblages par gousset en acier S235 et S355 Les Tables contiennent des données relatives à la géométrie ainsi que les valeurs de calcul correspondantes des résistances ultimes des assemblages ; elles remplacent le chapitre « Assemblages par plaques frontales et boulons HR » des anciennes Tables C9.1 de 1983 / 2002. Le calcul de ces assemblages par plaque frontale est basé sur les hypothèses du modèle de la méthode des composants décrite dans la norme SN EN 1993-1-8. Les vérifications sont effectuées selon la norme SIA 263:2013. Les assemblages par gousset remplacent les assemblages par double cornière, (telle...

  10. Le cosmos et le lotus confessions d'un astrophysicien

    CERN Document Server

    Trinh, Xuan Thuan

    2011-01-01

    Que nous dit vraiment la science sur la nature de l'univers, sur son origine et son avenir ? Par quel mystère le langage mathématique, pure création de l'esprit humain, se révèle-t-il aussi performant pour nous décrire les phénomènes physiques, de l'infiniment petit à l'infiniment grand ? S'il existe un ordre du monde, ce que nous en disent la physique quantique et la théorie de la relativité est-il compatible avec ce qu'enseigne le bouddhisme ? Et que peut-on en conclure concernant notre propre vie ? A ces questions passionnantes et à beaucoup d'autres, le célèbre astrophysicien Trinh Xuan Thuan répond ici d'une façon personnelle, en s'appuyant sur son expérience. Son itinéraire l'a placé d'emblée à la confluence de trois cultures : issu d'une famille de lettrés vietnamiens imprégnée de traditions bouddhiste et confucéenne, il a reçu une éducation à la française puis une formation scientifique à l'américaine. Une telle richesse de points de vue lui permet d'apporter, non pas de...

  11. Caractérisation de jonctions ultra-minces réalisées par dopage laser

    Science.gov (United States)

    Kerrien, G.; Sarnet, T.; Débarre, D.; Hernandez, M.; Zahorski, D.; Venturini, J.; Laviron, C.; Semeria, M. N.; Boulmer, J.

    2003-06-01

    Cette étude concerne les techniques de recuit laser (LTP) et de dopage laser direct (GILD) de jonctions ultra-minces, nécessaires à la fabrication des composants microélectroniques du futur (générations CMOS sub 0,1 μm). Des jonctions de 20 à 80 nm sont réalisées à l'aide d'un laser à excimères. Le procédé est suivi en temps réel grâce à l'analyse de la réflectivité transitoire à 675 nm. L'évolution de l'activation des dopants est ensuite caractérisée par spectroscopie IR (FTIR). Les résultats obtenus permettent de caractériser les jonctions en termes d'épaisseur dopées, concentration et résistivité. Une comparaison avec des caractérisations classiques (mesures électriques de résistivité, profils SIMS) permet de valider ces mesures et de mettre en évidence l'intérêt des techniques optiques pour la caractérisation in-situ et ex-situ des couches minces dopées réalisées par laser.

  12. Multi-Scale Entrainment of Coupled Neuronal Oscillations in Primary Auditory Cortex

    Science.gov (United States)

    O’Connell, M. N.; Barczak, A.; Ross, D.; McGinnis, T.; Schroeder, C. E.; Lakatos, P.

    2015-01-01

    Earlier studies demonstrate that when the frequency of rhythmic tone sequences or streams is task relevant, ongoing excitability fluctuations (oscillations) of neuronal ensembles in primary auditory cortex (A1) entrain to stimulation in a frequency dependent way that sharpens frequency tuning. The phase distribution across A1 neuronal ensembles at time points when attended stimuli are predicted to occur reflects the focus of attention along the spectral attribute of auditory stimuli. This study examined how neuronal activity is modulated if only the temporal features of rhythmic stimulus streams are relevant. We presented macaques with auditory clicks arranged in 33 Hz (gamma timescale) quintets, repeated at a 1.6 Hz (delta timescale) rate. Such multi-scale, hierarchically organized temporal structure is characteristic of vocalizations and other natural stimuli. Monkeys were required to detect and respond to deviations in the temporal pattern of gamma quintets. As expected, engagement in the auditory task resulted in the multi-scale entrainment of delta- and gamma-band neuronal oscillations across all of A1. Surprisingly, however, the phase-alignment, and thus, the physiological impact of entrainment differed across the tonotopic map in A1. In the region of 11–16 kHz representation, entrainment most often aligned high excitability oscillatory phases with task-relevant events in the input stream and thus resulted in response enhancement. In the remainder of the A1 sites, entrainment generally resulted in response suppression. Our data indicate that the suppressive effects were due to low excitability phase delta oscillatory entrainment and the phase amplitude coupling of delta and gamma oscillations. Regardless of the phase or frequency, entrainment appeared stronger in left A1, indicative of the hemispheric lateralization of auditory function. PMID:26696866

  13. Multi-scale entrainment of coupled neuronal oscillations in primary auditory cortex.

    Directory of Open Access Journals (Sweden)

    Monica Noelle O'Connell

    2015-12-01

    Full Text Available Earlier studies demonstrate that when the frequency of rhythmic tone sequences or streams is task relevant, ongoing excitability fluctuations (oscillations of neuronal ensembles in primary auditory cortex (A1 entrain to stimulation in a frequency dependent way that sharpens frequency tuning. The phase distribution across A1 neuronal ensembles at time points when attended stimuli are predicted to occur reflects the focus of attention along the spectral attribute of auditory stimuli. This study examined how neuronal activity is modulated if only the temporal features of rhythmic stimulus streams are relevant. We presented macaques with auditory clicks arranged in 33 Hz (gamma timescale quintets, repeated at a 1.6 Hz (delta timescale rate. Such multi-scale, hierarchically organized temporal structure is characteristic of vocalizations and other natural stimuli. Monkeys were required to detect and respond to deviations in the temporal pattern of gamma quintets. As expected, engagement in the auditory task resulted in the multi-scale entrainment of delta- and gamma-band neuronal oscillations across all of A1. Surprisingly, however, the phase-alignment, and thus, the physiological impact of entrainment differed across the tonotopic map in A1. In the region of 11-16 kHz representation, entrainment most often aligned high excitability oscillatory phases with task-relevant events in the input stream and thus resulted in response enhancement. In the remainder of the A1 sites, entrainment generally resulted in response suppression. Our data indicate that the suppressive effects were due to low excitability phase delta oscillatory entrainment and the phase amplitude coupling of delta and gamma oscillations. Regardless of the phase or frequency, entrainment appeared stronger in left A1, indicative of the hemispheric lateralization of auditory function.

  14. Onset of liquid droplet entrainment on a direct vessel injection system for APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-sol; Lee, Jae-Young [Handong Global University, Pohang (Korea, Republic of); Kim, Jong-Rok; Euh, Dong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this research, a series of visualization works was conducted to understand droplet entrainment of the flow pattern generated in direct vessel injection system(DVI) of Korea nuclear power plant, APR 1400. In the emergency situation of a nuclear power plant, reliability of DVI cooling can be an important issue. It is known that, the amount and the rate of entrainment during the DVI cooling process can significantly affect the total heat removal. To visualize the film Reynolds number closely related with onset of droplet entrainment induced by falling film flow and lateral air flow in a small gap, confocal chromatic sensing method for measuring accurately film thickness and depth averaging particle image velocimetry for film velocity were used. The results have been post processed 4G Insight software. By measuring two dimensional film Reynolds number, we can predict the onset of droplet entrainment and obtain visible breakup region intuitively. To visualize the droplet entrainment induced by falling film flow and lateral air flow in a small gap, shadowgraph method with CCD camera (2200fps, 1280 pixel X 800 pixel, ) on coated plate with super water-repellent agent was used. The results have been post processed using 4G Insight software. By measuring two dimensional film Reynolds number, we can predict the onset of droplet entrainment and obtain visible breakup region intuitively. By adopting both super hydrophobic coating method and shadowgraph method, entrainment in a narrow gap was successfully visualized that has rarely performed before and meaningful results for DVI system research fields have been made.

  15. Le je en jeu dans l'apprentissage du français par improvisation

    Directory of Open Access Journals (Sweden)

    Rachel Lascar-Feldman

    2015-03-01

    Full Text Available L'apprentissage d'une langue étrangère met en jeu les rapports que l'apprenant entretient avec lui-même, avec son identité, avec l'autre. La psychanalyse nous offre des clés pour comprendre les processus internes liés à l'émission de la langue parlée. Une didactique basée sur les improvistions théâtrales permet de sortir du champ purement cérébral de l'apprentissage et relie l'internalisation de la nouvelle langue aux émotions provoquées par le jeu. Parler correspond alors autant à une nécessité qu'à un plaisir. Pour ce faire l'expression orale ne peut plus demeurer le parent pauvre de l'enseignement des langues étrangères et doit bénéficier d'un espace temporel et spatial propre. Les techniques du psychodrame et du théâtre offrent des ouvertures précieuses pour tout pédagogue.

  16. La reconstruction du sourcil par greffon composite du cuir chevelu: une astuce pour faciliter la technique

    Science.gov (United States)

    El Omari, Mounia; El Mazouz, Samir; Gharib, Noureddine; EL Abbassi, Abdallah

    2015-01-01

    Les sourcils jouent un rôle important dans l’équilibre esthétique du visage. Leur reconstruction ou ophriopoïése, après séquelle de brûlure fait partie intégrante du programme de réhabilitation de la face brûlée. Plusieurs techniques ont été décrites. Nous insistons ici sur l'intérêt d'une technique simple, à la portée de tous les chirurgiens, et dont la méthode et les résultats peuvent être améliorés par un dessin bien planifié des zones donneuse et receveuse: la greffe composite prélevée au niveau du cuir chevelu dessinée à l'aide d'un calque du sourcil controlatéral. PMID:26401195

  17. Apprendre et maîtriser LabVIEW par ses applications

    CERN Document Server

    Martaj, Nadia

    2014-01-01

    Cet ouvrage traite de l'apprentissage du langage LabVIEW a travers ses applications dans des domaines industriels et academiques, qui permettront a l'ingenieur, technicien ou etudiant d'apprehender rapidement et efficacement ce langage. L'ouvrage commence, dans la partie I, par traiter les differents types de donnees du langage LabVIEW (tableaux, clusters, complexes, chaines de caracteres...), leur manipulation dans des structures d'execution (boucles While, For, la structure Condition, etc.), le langage textuel MathScript, des scripts Matlab, la boite de calcul utilisant la syntaxe du langage C ainsi que les nœuds de propriete qui permettent d'obtenir ou definir la propriete d''un VI. Cette etude est menee a travers des applications d'ingenierie.La partie II est consacree a l'etude de l'outil « Conception de controle et simulation » avec lequel nous pouvons simuler des systemes analogiques ou discrets.La partie III contient differentes applications qui traitent de nombreux themes comme la regulation (diff...

  18. Tumeur brune du maxillaire révélatrice d'hyperparathyroidie primaire: à propos d'un cas et revue de la littérature

    Science.gov (United States)

    Malika, Fassih; Taali, Loubna; Akssim, Mohamed; Reda, Abada; Rouadi, Sami; Mahtar, Mohamed; Roubal, Mohamed; Essaadi, Mustapha; Kadiri, Mohamed Fatmi El

    2013-01-01

    Les tumeurs brunes sont des lésions ostéolytiques rarement révélatrices des hyperparathyroïdies. Elles surviennent habituellement au stade terminal de l'hyperparathyroïdie primaire ou secondaire. Durant les 3 dernières décennies, le diagnostic des hyperparathyroïdies est le plus souvent fait à la phase asymptomatique grâce aux dosages systématiques du calcium et l'avènement des nouvelles techniques, de dosage de la parathormone. Nous rapportons l'observation d'une patiente avec hyperparathyroïdie primaire révélée par une tumeur du maxillaire, dont la TDM avait mis en évidence un processus ostéolytique agressif. L'intervention chirurgicale a consisté en une maxillectomie droite avec reconstruction. Le résultat anatomo-pathologique a conclu en une tumeur à cellule géantes bénigne du maxillaire. Le diagnostic de tumeur brune a été évoqué et confirmé après la réalisation d'un bilan phosphocalcique qui a mis en évidence une hypercalcémie, avec une hypophosphorémie. La recherche étiologique a objectivé à la TDM cervicale un processus en situation rétro et infra thyroïdienne droite en faveur d'un adénome parathyroïdien. Le dosage de la parathormone: 322 pmol/L a confirmé le diagnostic. Nous rappelons à travers cette observation la difficulté d’établir un diagnostic correct chez les patients avec un processus ostéolytique du maxillaire et la nécessité de rechercher une hyperparathyroïdie devant une lésion à cellules géantes vue le caractère insidieux de cette endocrinopathie. PMID:23503933

  19. Financiarisation de la gestion et concentration des risques : une étude de cas d'un gestionnaire de fonds public

    Directory of Open Access Journals (Sweden)

    Frédéric Hanin

    2012-05-01

    Full Text Available Cet article propose une analyse de la financiarisation de la gestion à partir de l’étude du cas de la principale institution financière publique au Canada, la Caisse de Dépôt et Placement du Québec. Cette évolution de la gestion est documentée ici à travers deux éléments. Le premier élément est le modèle d'affaire mis de l'avant par l'institution avec l'arrivée d'un nouveau PDG en 2002 qui repose sur une nouvelle interprétation du mandat de l'institution et de sa responsabilité sociétale. Le second élément est la réforme de l'organisation interne de la Caisse avec l'adoption d'un modèle organisationnel de conglomérat financier basé sur l'utilisation indirecte des produits dérivés ou indirect à travers des produits structurés. Cette étude de cas permet également d’analyser les transformations récentes des modes de gouvernance dans les institutions financières.This article proposes an analysis of the financialization of public pension’s asset managers through the case study of the most important one in Canada. The 2008 fallout is the result of structural changes in the regulation and management of the organization. Two elements are here at the core of financialization. First, the new business model was built on a different analysis of the mission of the institution. Second, the creation of "value added" was expected by the use of interactions between portfolios, facilitated by the development of derivatives and structured financial products. This case study is also interesting to analyze the transformation of the governance structure in the financial sector.

  20. Etude sur la méthode de réparation des ouvrages métalliques par collage de matériau composite Cas de la ligne de pipeline GZ1 40’’

    OpenAIRE

    FEKIH, Mohammed

    2014-01-01

    Notre étude comprend une simulation numérique d'une structure de pipeline en acier API 5L X60 après les dommages causés par la corrosion localisée. La méthode consiste à envisager une structure de pipeline sans défauts et après l'introduction d'un défaut elliptique et enfin à examiner le comportement de la structure multicouche après la capacité de réparation à base de composite. Les résultats obtenus par le logiciel ANSYS ont montré la variation de l'état de contrainte. Le champ de contraint...

  1. Répartition du potentiel électrocinétique imposée par un dipôle de courant excentré dans une plaque conductrice rectangulaire partiellement cloisonnée

    OpenAIRE

    Troquet, J.; Lambin, Ph.

    1985-01-01

    Connaissant les distributions de potentiel électrique qui apparaissent dans une plaque conductrice rectangulaire lorsque cette dernière est alimentée par une paire source-puits parallèle à l'un ou l'autre côté, nous comparons cette situation contrôle aux conséquences d'un cloisonnement de la plaque sur un quart de sa longueur par une ou deux fentes avec pour effet habituel de réduire la transmission de courant à l'entrée de la partie cloisonnée. Corrélativement, les cloisons introduisent des ...

  2. Evaluation du coût de la prise en charge des enfants infectés par le VIH à Abidjan (Côte d'Ivoire) en 1996-1997

    OpenAIRE

    Giraudon, I; Leroy, V.; Msellati, Philippe; Elenga, N.; Ramon, R.; C. Welffens-Ekra; Dabis, F.

    1999-01-01

    Le coût de la prise en charge d'un enfant infecté par le VIH en Afrique est mal connu mais cette variable doit être prise en compte dans les analyses coût-efficacité des stratégies visant à réduire la transmission verticale du VIH. L'objectif de ce travail était de mesurer, à Abdijan (Côte d'Ivoire), le coût direct de la prise en charge médicale pendant leur première année de vie des enfants nés de mères infectées par le VIH1 (VIH+) et d'estimer le surcoût lié à l'infection pédiatrique à VIH ...

  3. « Quantifier » le paysage au long d’un itinéraire à partir d'un échantillonnage photographique au sol

    Directory of Open Access Journals (Sweden)

    Madeleine Griselin

    2004-01-01

    Full Text Available Les échantillonnages photographiques représentatifs d'un espace, enregistrés dans des banques d’images, permettent aujourd’hui d’avoir accès à un nouveau panel d’informations sur le paysage (architecture du paysage, ambiances, couleurs…. L’exemple présenté est issu d’une enquête permettant de caractériser de manière objective les paysages vus depuis deux projets d'itinéraires pédestres vers Compostelle en Franche-Comté. Il s’agissait de se mettre dans la situation des futurs utilisateurs en photographiant le paysage tel qu’il s'offre à la vue du piéton marchant vers Compostelle et d'apprécier la variation paysagère qui rythme la marche, pouvant la rendre agréable ou fastidieuse. À partir de l’analyse des photographies, traitées par triptyque, une typologie des paysages rencontrés est réalisée. La navigation dans les banques d'images et l'intégration dans un SIG permettent de visualiser les paysages tout au long des tracés. Une représentation en histogramme facilite la distinction visuelle des types et permet de dégager les variations, les “ rythmes ” du paysage. La prise en compte des processus de perception par les utilisateurs d’un espace montre à quel point le paysage se construit à travers les déplacements. Une même région, assez homogène au premier abord, va se révéler très diversifiée – en approche linéaire – par les rythmes qu'engendre la marche. Cette pratique permet de lier espace, mobilité et temporalité.

  4. Commande optimisee d'un ensemble convertisseur-machine synchrone autopilotée fonctionnant en mode dégradé biphasé

    Science.gov (United States)

    Fan, Yuchao; Hautier, J. P.

    1994-01-01

    This paper presents the remedial strategies for a converter-synchronous machine system, which would be used in case of conduction faults in the converter. After an analysis of the influence of transistor drive faults, in the conversion system characteristics, a remedial strategy in single-phase operation is proposed to palliate the consequences of the transistor faults when the neutral point of synchronous machine is not connected. Developed torque in this operating mode is pulsating. To eliminate this inconvenient which disturbs the speed regulation, an optimized remedial strategy in two-phase operation is then proposed. The power part is modified and the neutral point of synthronous machine is connected to DC voltage. Simulation and experimentation validate the proposed strategies. Cet article présente des marches dégradées optimisées applicables à un ensemble convertisseur-machine synchrone, lorsque des défauts de conduction apparaissent au niveau du convertisseur. Après analyse de l'influence d'un défaut de commande sur les caractéristiques de l'ensemble d'entraînement, une stratégie de rattrapage, en marche dégradée monophasée, est d'abord proposée pour pallier aux inconvénients de deux types de défauts lorsque le neutre de la machine est isolé. Dans ce mode de marche, le couple développé par la machine synchrone est pulsatoire. Afin d'éviter cet inconvénient, nous proposons, ensuite, une marche dégradée en mode biphasé par modification de la structure de puissance, en reliant le neutre de la machine au point milieu d'alimentation. Enfin, les stratégies de commande proposées sont validées par la simulation et l'expérience.

  5. Uncertainty associated with convective wet removal of entrained aerosols in a global climate model

    Science.gov (United States)

    Croft, B.; Pierce, J. R.; Martin, R. V.; Hoose, C.; Lohmann, U.

    2012-11-01

    The uncertainties associated with the wet removal of aerosols entrained above convective cloud bases are investigated in a global aerosol-climate model (ECHAM5-HAM) under a set of limiting assumptions for the wet removal of the entrained aerosols. The limiting assumptions for the wet removal of entrained aerosols are negligible scavenging and vigorous scavenging (either through activation, with size-dependent impaction scavenging, or with the prescribed fractions of the standard model). To facilitate this process-based study, an explicit representation of cloud-droplet-borne and ice-crystal-borne aerosol mass and number, for the purpose of wet removal, is introduced into the ECHAM5-HAM model. This replaces and is compared with the prescribed cloud-droplet-borne and ice-crystal-borne aerosol fraction scavenging scheme of the standard model. A 20% to 35% uncertainty in simulated global, annual mean aerosol mass burdens and optical depth (AOD) is attributed to different assumptions for the wet removal of aerosols entrained above convective cloud bases. Assumptions about the removal of aerosols entrained above convective cloud bases control modeled upper tropospheric aerosol concentrations by as much as one order of magnitude. Simulated aerosols entrained above convective cloud bases contribute 20% to 50% of modeled global, annual mean aerosol mass convective wet deposition (about 5% to 10% of the total dry and wet deposition), depending on the aerosol species, when including wet scavenging of those entrained aerosols (either by activation, size-dependent impaction, or with the prescribed fraction scheme). Among the simulations, the prescribed fraction and size-dependent impaction schemes yield the largest global, annual mean aerosol mass convective wet deposition (by about two-fold). However, the prescribed fraction scheme has more vigorous convective mixed-phase wet removal (by two to five-fold relative to the size-dependent impaction scheme) since nearly all

  6. Nouvelle methode d'optimisation du cout d'un vol par l'utilisation d'un systeme de gestion de vol et sa validation sur un avion Lockheed L-1011 TriStar

    Science.gov (United States)

    Gagne, Jocelyn

    Usually, flights optimization and planning will take place before flight, on ground. However, it is not always feasible to do such optimization, or sometime unpredictable events may force pilots to change the flight path. In those circumstances, the pilots can only rely on charts or their Flight Management System (FMS) in order to maintain an economic flight. However, those FMS often rely on those same charts, which will not take into consideration different parameters, such as the cost index, the length on the flight or the weather. Even if some FMS take into consideration the weather, they may only rely on manually entered or limited data that could be outdated, insufficient or incomplete. The alleviate these problems, the function program's that was developed is mainly to determine the optimum flight profile for an aircraft, or more precisely, at the lowest overall cost, considering a take-off weight and weather conditions. The total cost is based on the value of time as well as the cost of fuel, resulting in the use of a ratio called the cost index. This index allows both to prioritize either the time or fuel consumption according to the costs related to a specific flight and/or airline. Thus, from a weight, the weather (wind, temperature, pressure), and the cost index, the program will calculate from the "Performance DataBase" (PDB) of a specific airplane an optimal flight profile over a given distance. The algorithm is based on linear interpolations in the performances tables using the Lagrange method. Moreover, in order to fully optimize the flight, the current program can, according to departure date and coordinates, download the latest available forecast from environment Canada website and calculate the optimum flight accordingly. The forecast data use by the program take the form of a 0.6 × 0.6 degrees grid in which the effects of wind, pressure and temperature are interpolated according to the aircraft geographical position and time. Using these tables, performances and forecasts, the program is therefore able to calculate the optimum profile from ground, but also in flight, if any change would occur on the path. Because all data is tabulated and not calculated, the required calculation power remains low, resulting in a short calculation time. Keywords: optimization, algorithm, simulation, cost.

  7. Nearly singular surfaces: origins of small-scale cutoff in 3D viscous entrainment

    Science.gov (United States)

    Zhang, Wendy

    2004-11-01

    Entrainment of a low-viscosity fluid against surface tension effects by a high-viscosity fluid often results in nearly singular steady-state interface shapes. Recent studies (Eggers PRL 01; Lorenceau et al. PRL 03) reveal that, in 2D, the viscous coupling between flows in the two fluids produces a small-scale cutoff which scales as (μ_0/μ)^4/3, where μ0 is the smaller viscosity. In contrast, results of a long-wavelength model of viscous entrainment from a nozzle show that the cutoff in 3D results from a different mechanism. The resultant cutoff lengthscale depends strongly on the boundary conditions imposed on the entrained spout shape at the nozzle opening but has no leading-order dependence on μ0 / μ. This is because viscous coupling has a far weaker effect in 3D than in 2D and only produces an exponentially small cutoff. Any mismatch between the entrainment dynamics on the largest lengthscale, as imposed by nozzle boundary conditions, and the dynamics on the smallest lengthscale necessary for the formation of a steady-state singularity produces a more appreciable cutoff. The lack of dependence on the viscosity contrast has been observed in 3D entrainment experiments (Cohen & Nagel, PRL 02).

  8. Positive feedback and momentum growth during debris-flow entrainment of wet bed sediment

    Science.gov (United States)

    Iverson, R.M.; Reid, M.E.; Logan, M.; LaHusen, R.G.; Godt, J.W.; Griswold, J.P.

    2011-01-01

    Debris flows typically occur when intense rainfall or snowmelt triggers landslides or extensive erosion on steep, debris-mantled slopes. The flows can then grow dramatically in size and speed as they entrain material from their beds and banks, but the mechanism of this growth is unclear. Indeed, momentum conservation implies that entrainment of static material should retard the motion of the flows if friction remains unchanged. Here we use data from large-scale experiments to assess the entrainment of bed material by debris flows. We find that entrainment is accompanied by increased flow momentum and speed only if large positive pore pressures develop in wet bed sediments as the sediments are overridden by debris flows. The increased pore pressure facilitates progressive scour of the bed, reduces basal friction and instigates positive feedback that causes flow speed, mass and momentum to increase. If dryer bed sediment is entrained, however, the feedback becomes negative and flow momentum declines. We infer that analogous feedbacks could operate in other types of gravity-driven mass flow that interact with erodible beds. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  9. Experimental investigations on a common centrifugal pump operating under gas entrainment conditions

    Energy Technology Data Exchange (ETDEWEB)

    Schäfer, Thomas, E-mail: thomas.schaefer@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics (Germany); Neumann, Martin [Technische Universität Dresden, AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering (Germany); Bieberle, André [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics (Germany); Hampel, Uwe [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics (Germany); Technische Universität Dresden, AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering (Germany)

    2017-05-15

    Highlights: • The pump performance has been evaluated for several gas entrainment conditions. • The gas entraining flow regime has a large impact on the pump performance. • High-resolution gamma-ray computed tomography (HireCT) has been applied. • Gas holdup inside the operating impeller has been visualized and quantified. • Gas holdup profiles along selected streamlines have been calculated. - Abstract: This paper presents an experimental study on the effects of additional gas entrainment in centrifugal pumps designed for conveying liquid phases only. The pump performance has been evaluated for several gas entrainment conditions, and for various operational settings of the pump, such as its alignment and the rotational speed of the impeller. As a main performance indicator the impact of entrained gas on the hydraulic power of the pump has been analyzed using experimental data. Additionally, high-resolution gamma-ray computed tomography (HireCT) operated in time-averaged rotation-synchronized scanning mode has been applied to quantify local phase fraction distributions inside the rapidly rotating pump impeller. Based on these quantitative tomographic measurements, gas holdup profiles along selected streamlines have been calculated and gas accumulation areas inside the impeller chambers have been visualized. Thus, various internally accumulated gas holdup patterns have been identified and, eventually, associated with characteristic pump performance behaviors. Moreover, the tomographic measuring method allowed an enhanced gas holdup analysis in specified pump compartments. As a result, the related specific gas and liquid phase holdup profiles have been evaluated.

  10. Searching for roots of entrainment and joint action in early musical interactions.

    Science.gov (United States)

    Phillips-Silver, Jessica; Keller, Peter E

    2012-01-01

    When people play music and dance together, they engage in forms of musical joint action that are often characterized by a shared sense of rhythmic timing and affective state (i.e., temporal and affective entrainment). In order to understand the origins of musical joint action, we propose a model in which entrainment is linked to dual mechanisms (motor resonance and action simulation), which in turn support musical behavior (imitation and complementary joint action). To illustrate this model, we consider two generic forms of joint musical behavior: chorusing and turn-taking. We explore how these common behaviors can be founded on entrainment capacities established early in human development, specifically during musical interactions between infants and their caregivers. If the roots of entrainment are found in early musical interactions which are practiced from childhood into adulthood, then we propose that the rehearsal of advanced musical ensemble skills can be considered to be a refined, mimetic form of temporal and affective entrainment whose evolution begins in infancy.

  11. Searching for roots of entrainment and joint action in early musical interactions

    Directory of Open Access Journals (Sweden)

    Jessica ePhillips-Silver

    2012-02-01

    Full Text Available When people play music and dance together, they engage in forms of musical joint action that are often characterized by a shared sense of rhythmic timing and affective state (i.e., temporal and affective entrainment. In order to understand the origins of musical joint action, we propose a model in which entrainment is linked to dual mechanisms (motor resonance and action simulation, which in turn support musical behavior (imitation and complementary joint action. To illustrate this model, we consider two generic forms of joint musical behavior: chorusing and turn-taking. We explore how these common behaviors can be founded on entrainment capacities established early in human development, specifically during musical interactions between infants and their caregivers. If the roots of entrainment are found in early musical interactions which are practiced from childhood into adulthood, then we propose that the rehearsal of advanced musical ensemble skills can be considered to be a refined, mimetic form of temporal and affective entrainment whose evolution begins in infancy.

  12. Numerical simulations of transient air entrainment by rough and smooth plunging jets

    Science.gov (United States)

    Kiger, Ken; Kharoua, Nabil; Khezzar, Lyes

    2012-11-01

    Plunging jets are intimately linked to the process of air or gas entrainment into liquid pools, and can play either a beneficial or detrimental role in many environmental and industrial flows. The purpose of the present work is to assess the capability of combined LES/VOF algorithms to simulate water/air plunging jet flows, starting with the transient impact of the free jet, initial cavity formation, pinch off, and evolution towards a continuous entrainment phase. We focus on what happens in the transient impact phase for weakly and highly disturbed jets, operating with impact conditions of Re = UD / ν = 10 , 500 , We = ρU2 D / σ = 300 and Fr =U2 / gD = 83 . In particular, the study investigates the ability of the simulations to capture liquid surface instabilities and the influence of the exiting jet turbulence content on the entrainment behavior. The results indicate that the qualitative behavior of the entrainment process follows very closely what is observed in experiments, with the rough jet exhibiting surface instabilities at impact that are not present in the smooth jet. These have an effect on the development of the initial air cavity and interfacial area, leading to a doubling of the interfacial area for a nominally similar entrained volume of air.

  13. Impact of reduced near-field entrainment of overpressured volcanic jets on plume development

    Science.gov (United States)

    Saffaraval, Farhad; Solovitz, Stephen A.; Ogden, Darcy E.; Mastin, Larry G.

    2012-01-01

    Volcanic plumes are often studied using one-dimensional analytical models, which use an empirical entrainment ratio to close the equations. Although this ratio is typically treated as constant, its value near the vent is significantly reduced due to flow development and overpressured conditions. To improve the accuracy of these models, a series of experiments was performed using particle image velocimetry, a high-accuracy, full-field velocity measurement technique. Experiments considered a high-speed jet with Reynolds numbers up to 467,000 and exit pressures up to 2.93 times atmospheric. Exit gas densities were also varied from 0.18 to 1.4 times that of air. The measured velocity was integrated to determine entrainment directly. For jets with exit pressures near atmospheric, entrainment was approximately 30% less than the fully developed level at 20 diameters from the exit. At pressures nearly three times that of the atmosphere, entrainment was 60% less. These results were introduced into Plumeria, a one-dimensional plume model, to examine the impact of reduced entrainment. The maximum column height was only slightly modified, but the critical radius for collapse was significantly reduced, decreasing by nearly a factor of two at moderate eruptive pressures.

  14. Getting the beat: entrainment of brain activity by musical rhythm and pleasantness.

    Science.gov (United States)

    Trost, Wiebke; Frühholz, Sascha; Schön, Daniele; Labbé, Carolina; Pichon, Swann; Grandjean, Didier; Vuilleumier, Patrik

    2014-12-01

    Rhythmic entrainment is an important component of emotion induction by music, but brain circuits recruited during spontaneous entrainment of attention by music and the influence of the subjective emotional feelings evoked by music remain still largely unresolved. In this study we used fMRI to test whether the metric structure of music entrains brain activity and how music pleasantness influences such entrainment. Participants listened to piano music while performing a speeded visuomotor detection task in which targets appeared time-locked to either strong or weak beats. Each musical piece was presented in both a consonant/pleasant and dissonant/unpleasant version. Consonant music facilitated target detection and targets presented synchronously with strong beats were detected faster. FMRI showed increased activation of bilateral caudate nucleus when responding on strong beats, whereas consonance enhanced activity in attentional networks. Meter and consonance selectively interacted in the caudate nucleus, with greater meter effects during dissonant than consonant music. These results reveal that the basal ganglia, involved both in emotion and rhythm processing, critically contribute to rhythmic entrainment of subcortical brain circuits by music.

  15. Entrainability of cell cycle oscillator models with exponential growth of cell mass.

    Science.gov (United States)

    Nakao, Mitsuyuki; Enkhkhudulmur, Tsog-Erdene; Katayama, Norihiro; Karashima, Akihiro

    2014-01-01

    Among various aspects of cell cycle, understanding synchronization mechanism of cell cycle is important because of the following reasons. (1)Cycles of cell assembly should synchronize to form an organ. (2) Synchronizing cell cycles are required to experimental analysis of regulatory mechanisms of cell cycles. (3) Cell cycle has a distinct phase relationship with the other biological rhythms such as circadian rhythm. However, forced as well as mutual entrainment mechanisms are not clearly known. In this study, we investigated entrainability of cell cycle models of yeast cell under the periodic forcing to both of the cell mass and molecular dynamics. Dynamics of models under study involve the cell mass growing exponentially. In our result, they are shown to allow only a limited frequency range for being entrained by the periodic forcing. In contrast, models with linear growth are shown to be entrained in a wider frequency range. It is concluded that if the cell mass is included in the cell cycle regulation, its entrainability is sensitive to a shape of growth curve assumed in the model.

  16. The neural basis of audiomotor entrainment: An ALE meta-analysis

    Directory of Open Access Journals (Sweden)

    Léa A. S. Chauvigné

    2014-09-01

    Full Text Available Synchronization of body movement to an acoustic rhythm is a major form of entrainment, such as occurs in dance. This is exemplified in experimental studies of finger tapping. Entrainment to a beat is contrasted with movement that is internally driven and is therefore self-paced. In order to examine brain areas important for entrainment to an acoustic beat, we meta-analyzed the functional neuroimaging literature on finger tapping (43 studies using activation likelihood estimation (ALE meta-analysis with a focus on the contrast between externally-paced and self-paced tapping. The results demonstrated a dissociation between two subcortical systems involved in timing, namely the cerebellum and the basal ganglia. Externally-paced tapping highlighted the importance of the spinocerebellum, most especially the vermis, which was not activated at all by self-paced tapping. In contrast, the basal ganglia, including the putamen and globus pallidus, were active during both types of tapping, but preferentially during self-paced tapping. These results suggest a central role for the spinocerebellum in audiomotor entrainment. We conclude with a theoretical discussion about the various forms of entrainment in humans and other animals.

  17. Interpretations of frequency domain analyses of neural entrainment: periodicity, fundamental frequency, and harmonics

    Directory of Open Access Journals (Sweden)

    Hong eZhou

    2016-06-01

    Full Text Available Brain activity can follow the rhythms of dynamic sensory stimuli, such as speech and music, a phenomenon called neural entrainment. It has been hypothesized that low-frequency neural entrainment in the neural delta and theta bands provides a potential mechanism to represent and integrate temporal information. Low-frequency neural entrainment is often studied using periodically changing stimuli and is analyzed in the frequency domain using the Fourier analysis. The Fourier analysis decomposes a periodic signal into harmonically related sinusoids. However, it is not intuitive how these harmonically related components are related to the response waveform. Here, we explain the interpretation of response harmonics, with a special focus on very low-frequency neural entrainment near 1 Hz. It is illustrated why neural responses repeating at f Hz do not necessarily generate any neural response at f Hz in the Fourier spectrum. A strong neural response at f Hz indicates that the time scales of the neural response waveform within each cycle match the time scales of the stimulus rhythm. Therefore, neural entrainment at very low frequency implies not only that the neural response repeats at f Hz but also that each period of the neural response is a slow wave matching the time scale of a f Hz sinusoid.

  18. Frequency-dependent entrainment of neocortical slow oscillation to repeated optogenetic stimulation in the anesthetized rat.

    Science.gov (United States)

    Kuki, Toshinobu; Ohshiro, Tomokazu; Ito, Shin; Ji, Zhi-Gang; Fukazawa, Yugo; Matsuzaka, Yoshiya; Yawo, Hiromu; Mushiake, Hajime

    2013-01-01

    Local field potential (LFP) slow oscillation (entrained to repeated external sensory stimuli. To better understand the neural mechanism underlying slow-oscillation generation and its entrainment to external stimuli, we delivered optical stimulation to the cortex of anesthetized rats that exogenously expressed the light-sensitive cation channel channelrhodopsin-2 (ChR2) and simultaneously monitored LFPs across cortical layers. We found that the LFPs could be effectively entrained to repeated optical stimulation at 1Hz in deep layers. A stimulus-triggered current-source density (CSD) analysis showed that the evoked oscillation had the same depth and temporal profile as the slow oscillations, indicating that both oscillations have the same neural mechanism. Optical stimulation primarily induced the transition from the cortical up to down state. These results suggest that the anesthetized rat cortex has an intrinsic mechanism that leads to oscillation near 1Hz; effective entrainment to the 1Hz stimulation reflects the resonated state of the cortex to that stimulus. Our study is the first to demonstrate optogenetic manipulation of cortical slow oscillation and provides a mechanistic explanation for slow-oscillation entrainment.

  19. Relationships of Entrainment Rate with Dynamical and Thermodynamic Properties in Shallow Convection

    Science.gov (United States)

    Lu, C.; Liu, Y.; Zhang, G. J.; Wu, X.; Endo, S.; Cao, L.; Li, Y.; Guo, X.

    2015-12-01

    This work examines the relationships of entrainment rate to vertical velocity, buoyancy, turbulent dissipation rate by applying stepwise principal component regression to observational data from shallow cumulus clouds collected during the Routine AAF [Atmospheric Radiation Measurement (ARM) Aerial Facility] Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign over the ARM Southern Great Plains (SGP) site near Lamont, Oklahoma. The cumulus clouds during the RACORO campaign simulated using a large eddy simulation (LES) model are also examined with the same approach. The analysis shows that combination of multiple variables can better represent entrainment rate in both the observations and LES than the single-variable fitting equations and the three commonly used parameterizations. A new parameterization is thus presented that relates entrainment rate to vertical velocity, buoyancy and dissipation rate; the effects of treating clouds as ensembles and humid shells surrounding cumulus clouds on the new parameterization are discussed. Physical mechanisms underlying the relationships of entrainment rate to vertical velocity, buoyancy and dissipation rate are also explored. Furthermore, the effects of relative humidity in the entrained dry air on the above relationships are discussed; a possible physical mechanism for the effects is explored.

  20. Inclined gravity currents filling basins: The influence of Reynolds number on entrainment into gravity currents

    Science.gov (United States)

    Hogg, Charlie A. R.; Dalziel, Stuart B.; Huppert, Herbert E.; Imberger, Jörg

    2015-09-01

    In many important natural and industrial systems, gravity currents of dense fluid feed basins. Examples include lakes fed by dense rivers and auditoria supplied with cooled air by ventilation systems. As we will show, the entrainment into such buoyancy driven currents can be influenced by viscous forces. Little work, however, has examined this viscous influence and how entrainment varies with the Reynolds number, Re. Using the idea of an entrainment coefficient, E, we derive a mathematical expression for the rise of the front at the top of the dense fluid ponding in a basin, where the horizontal cross-sectional area of the basin varies linearly with depth. We compare this expression to experiments on gravity currents with source Reynolds numbers, Res, covering the broad range 100 < Res < 1500. The form of the observed frontal rises was well approximated by our theory. By fitting the observed frontal rises to the theoretical form with E as the free parameter, we find a linear trend for E(Res) over the range 350 < Res < 1100, which is in the transition to turbulent flow. In the experiments, the entrainment coefficient, E, varied from 4 × 10-5 to 7 × 10-2. These observations show that viscous damping can be a dominant influence on gravity current entrainment in the laboratory and in geophysical flows in this transitional regime.