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Search Results: 1 - 10 of 200650 matches for " P.;Hervieu "
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Detection of Horizontal Two-Phase Flow Patterns Through a Neural Network Model
Crivelaro, K. C. O.;Seleghim Jr., P.;Hervieu, E.;
Journal of the Brazilian Society of Mechanical Sciences , 2002, DOI: 10.1590/S0100-73862002000100009
Abstract: one of the main problems related to the transport and manipulation of multiphase fluids concerns the existence of characteristic flow patterns and its strong influence on important operation parameters. a good example of this occurs in gas-liquid chemical reactors in which maximum efficiencies can be achieved by maintaining a finely dispersed bubbly flow to maximize the total interfacial area. thus, the ability to automatically detect flow patterns is of crucial importance, especially for the adequate operation of multiphase systems. this work describes the application of a neural model to process the signals delivered by a direct imaging probe to produce a diagnostic of the corresponding flow pattern. the neural model is constituted of six independent neural modules, each of which trained to detect one of the main horizontal flow patterns, and a last winner-take-all layer responsible for resolving when two or more patterns are simultaneously detected. experimental signals representing different bubbly, intermittent, annular and stratified flow patterns were used to validate the neural model.
Time-frequency analysis of intermittent two-phase flows in horizontal piping
Klein, F. L.;Seleghim Junior, P.;Hervieu, E.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2004, DOI: 10.1590/S1678-58782004000200009
Abstract: one of the main features associated to multiphase flows is the existence of characteristic dynamic structures according to which the different phases of a mixture of immiscible fluids can flow. the manifestation of one of these structures, known as flow pattern or regime, is determined by the flow rates as well as by physical and geometrical properties of the fluids and piping. the development of flow pattern characterization and diagnostic methods, and the associated transitions in between, is of crucial importance for an efficient engineering of such phenomena. time-frequency analysis is used in this work to characterize horizontal air-water intermittent flow regimes. more specifically, our main objective is to reveal the existence of sub-regimes inside the intermittent regimes region with the help of the corresponding time-frequency covariance, which is capable of detecting transitions by assessing the unstationarity associated with the corresponding transitions. experimental tests were conducted at the talc facility at cea-grenoble and an extensive database was obtained, covering several types of intermittent flow. a conductivity probe, consisting in two ring electrodes flush mounted to the pipe, delivered signals from which the time-frequency covariance was calculated from the corresponding gabor transform.
Detection of Horizontal Two-Phase Flow Patterns Through a Neural Network Model
Crivelaro K. C. O.,Seleghim Jr. P.,Hervieu E.
Journal of the Brazilian Society of Mechanical Sciences , 2002,
Abstract: One of the main problems related to the transport and manipulation of multiphase fluids concerns the existence of characteristic flow patterns and its strong influence on important operation parameters. A good example of this occurs in gas-liquid chemical reactors in which maximum efficiencies can be achieved by maintaining a finely dispersed bubbly flow to maximize the total interfacial area. Thus, the ability to automatically detect flow patterns is of crucial importance, especially for the adequate operation of multiphase systems. This work describes the application of a neural model to process the signals delivered by a direct imaging probe to produce a diagnostic of the corresponding flow pattern. The neural model is constituted of six independent neural modules, each of which trained to detect one of the main horizontal flow patterns, and a last winner-take-all layer responsible for resolving when two or more patterns are simultaneously detected. Experimental signals representing different bubbly, intermittent, annular and stratified flow patterns were used to validate the neural model.
Giant frequency dependence of dynamic freezing in nanocrystalline ferromagnetic LaCo0.5Mn0.5O3
R. Mahendiran,Y. Briead,M. Hervieu,B. Raveau,P. Schiffer
Physics , 2002, DOI: 10.1103/PhysRevB.68.104402
Abstract: This paper is withdrawn now and soon will be replaced by a complete study on LaCo0.5-MgxMn0.5O3.
Giant frequency dependence of dynamic freezing in nanocrystalline ferromagnetic LaCo0.5Mn0.5O3
R. Mahendiran,Y. Breard,M. Hervieu,B. Raveau,P. Schiffer
Physics , 2003,
Abstract: We have investigated the magnetic properties of nanocrystalline LaCo0.5Mn0.5O3. The temperature dependence of the imaginary part of the a.c. susceptibility shows a strongly frequency dependent maximum at a temperature, Tf, which is well below the ferromagnetic transition temperature (TC ~ 230 K). The frequency dependence of Tf obeys the Arrhenius relation, f = foexp(-Ea/kBT), with physically reasonable values of fo = 109 Hz and Ea/kB = 1518 K. The frequency shift of Tf per decade of frequency is one of the highest values observed in any magnetic system, and a similarly large value is also found in LaCo0.4Mg0.1Mn0.5O3, suggesting that such behavior is intrinsic despite the apparent presence of long range ferromagnetic order.
Liberté de religion (art. 9 CEDH): droit de ne pas être contraint de révéler ses convictions religieuses et prélèvement à la source de l’imp t cultuel. L’affaire Wasmuth c. Allemagne
Nicolas Hervieu
Stato, Chiese e Pluralismo Confessionale , 2011,
Abstract: Il contributo, apparso su Actualités Droits-Libertés del 20 février 2011 (CREDOF, http://credof.u-paris10.fr/) e destinato anche alla rivista telematica “Combats pour les droits de l’homme”, è pubblicato per la cortese disponibilità del Centre de Recherches et d’études sur les Droits Fondamentaux - Université Paris Ouest Nanterre La Défense.
Droit à l’instruction et liberté de religion (art. 2 du Protocole n° 1 et art. 9 CEDH): Conventionalité de la présence des crucifix dans les salles de classe d’écoles publiques. L’affaire Lautsi c. Italie
Nicolas Hervieu
Stato, Chiese e Pluralismo Confessionale , 2011,
Abstract: Il contributo, apparso su Actualités Droits-Libertés del 20 marzo 2011 (CREDOF, http://credof.u-paris10.fr/ - http://www.droits-libertes.org/article.php3?id_article=147), è pubblicato per la cortese disponibilità del Centre de Recherches et d’études sur les Droits Fondamentaux - Université Paris Ouest Nanterre La Défense. SOMMAIRE: 1. Introduction – 2. Les contraintes de conventionalité et la liberté étatique dans l’organisation de l’environnement scolaire: une articulation délicate pour les symboles religieux – 2.1. La soumission de l’aménagement de l’environnement scolaire à un minimum de contraintes de conventionalité – 2.2. La diversité européenne, source d’une large marge d’appréciation au profit des états – 3. Le principe conventionnel de neutralité: entre acrobaties jurisprudentielles et affaiblissement substantiel – 3.1. La minoration contestable de l’impact des crucifix exposés dans les salles de classe – 3.2. Que reste-t-il du principe de neutralité religieuse en matière scolaire? – 4. La portée du revirement.: In a particularly sensitive context, the Grand Chamber of the European Court of Human Rights has finally decided to reverse the solution adopted by the Chamber about the famous case Lautsi v. Italy (ECtHR, 2nd Sect. November 3, 2009, Lautsi v. Italy, Appl. No. 30814/06 – ADL’s November 3, 2009). By a majority of fifteen votes against two, the Grand Chamber refuses to condemn Italy for the presence of crucifixes in classrooms of its schools. Receptive to criticism of the solution in 2009, the Court decided to grant broad freedom to States regarding the presence of religious symbols in the school environment. But doing so, she carries out some acrobatics reasoning and reduces principle of neutrality.Lautsi v. Italy, Appl. No. 30814/06 – ADL’s November 3, 2009). By a majority of fifteen votes against two, the Grand Chamber refu
Liberté de religion (Art. 9 CEDH) : Reconnaissance conventionnelle du droit à l’objection de conscience
Nicolas Hervieu
Stato, Chiese e Pluralismo Confessionale , 2011,
Abstract: Il commento alla decisione della Corte europea dei Diritti dell’Uomo (Cour EDH, G.C. 7 juillet 2011, Bayatyan c. Arménie, Req. n° 23459/03), già pubblicato il 10 luglio 2011 su Les lettres d’actualité droits-libertés del CREDOF, è riprodotto per la cortese autorizzazione della Rivista e dell’Autore. SOMMAIRE: 1. Introduction. Sur l’existence d’un droit à l’objection de conscience – 2. La consécration du droit à l’objection de conscience: entre revirement de jurisprudence et correction tardive d’une interprétation passée – 3. Les implications du droit à l’objection de conscience : entre souhait d’effectivité et souci d’encadrement – 4. Conclusion.
Structure determination of a brownmillerite Ca2Co2O5 thin film by Precession Electron Diffraction
P. Boullay,V. Dorcet,O. Perez,C. Grygiel,W. Prellier,B. Mercey,M. Hervieu
Physics , 2009, DOI: 10.1103/PhysRevB.79.184108
Abstract: Calcium cobaltite thin films with a ratio Ca/Co=1 were grown on (101)-NdGaO3 substrate by the pulsed laser deposition technique. The structure of the deposited metastable phase is solved using a precession electron diffraction 3D dataset recorded from a cross-sectional sample. It is shown that an ordered oxygen-deficient Ca2Co2O5+d perovskite of the brownmillerite-type with lattice parameters a= 0.546nm, b=1.488nm and c=0.546nm (SG: Ibm2) has been stabilized using the substrate induced strain. The structure and microstructure of this metastable cobaltite is further discussed and compared to related bulk materials based on our transmission electron microscopy investigations
Ordering phenomena and transport properties of Bi1/2Sr1/2MnO3 single crystals
J. Hejtmanek,K. Knizek,Z. Jirak,M. Hervieu,C. Martin,M. Nevriva,P. Beran
Physics , 2002, DOI: 10.1063/1.1543911
Abstract: Measurements of the electrical and thermal conductivities, thermopower and paramagnetic susceptibility have been performed on single crystal samples of Bi1/2Sr1/2MnO3 and complemented with the X-ray powder diffraction data. A pronounced hysteretic behavior, observed below the cubic-to- orthorhombic transition at Tcrit = 535 K, is related to the onset of long-range charge order at TCO = 450 K and its further evolution down to about 330 K. The diffraction data suggest that the charge ordered state is formed by Zener pairs, represented by Mn4+ dimers linked by one extra eg electron, and is possibly stabilized by cooperative Bi,Sr displacements. An extremely low thermal conductivity is observed down to the lowest temperatures, without any recovery at the anti- ferromagnetic ordering temperature TN = 150 K. Such be- havior points to a presence of strong scatterers of phonons. Their possible origin can be linked to "optical-like" oscilla- tions which are associated with fluctuating charges within the Zener pairs.
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