Journal articles: 'Simulation transitoire'

1

Mnasri, Aida, and Ezzeddine Hadj Taieb. "Simulation numérique par éléments finis des écoulements transitoires à surface libre." La Houille Blanche, no. 5-6 (December 2019): 81–92. http://dx.doi.org/10.1051/lhb/2019032.

Full text

Abstract:

Une simulation numérique par des éléments finis des écoulements transitoires à surface libre dans les canaux prismatiques est présentée. Dans cette étude, l'écoulement est supposé unidirectionnel dans un canal de faible pente. Le modèle mathématique est constitué d'un système de deux équations aux dérivées partielles de type hyperbolique résolu numériquement par la méthode des éléments finis. Pour définir les fonctions d'interpolation dans la forme intégrale des résidus pondérés, la méthode de Galerkin a été utilisée. Dans les applications, différentes sections prismatiques sont examinées. Les régimes transitoires étudiés sont dus à des manœuvres de vanne placée en aval du canal, l'extrémité amont étant connectée à un réservoir de niveau constant. Dans ces conditions, le régime transitoire correspond à une évolution de l'écoulement d'un régime permanent initial vers un régime permanent final. Ces deux régimes sont supposés uniformes à débit constant défini par la formule de Manning. Les résultats obtenus concernent l'évolution des paramètres hydrauliques en différentes sections du canal, suite à la manœuvre en aval. Deux cas de manœuvres sont considérés ; le cas d'une ouverture et le cas d'une fermeture. L'étude a permis d'analyser la propagation des ondes de surface et la réflexion de ces ondes sur les deux extrémités du canal. En particulier, les résultats numériques montrent que lorsque la largeur du lit du canal est très petite (cas de la section triangulaire), les fluctuations des profondeurs sont rapidement amorties.

APA, Harvard, Vancouver, ISO, and other styles

2

-Baggio, Jacques. "Simulation de la réponse transitoire d'une diode laser à une impulsion ionisante." Revue de l'Electricité et de l'Electronique -, no. 04 (1997): 71. http://dx.doi.org/10.3845/ree.1997.050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Dassargues, A., A. Monjoie, J. Lambert, and A. Pierlot. "Etude régionale par éléments finis d'une nappe libre située dans les craies du crétacé en Belgique." Revue des sciences de l'eau 4, no. 1 (2005): 39–63. http://dx.doi.org/10.7202/705089ar.

Full text

Abstract:

La nappe aquifère de Hesbaye située au Nord-Ouest de Liège (Belgique) est logée dans les craies du Crétacé, surmontées d'une épaisse couche de limon. L'alimentation en eau de la région est assurée par les 60 000 m3 extraits Joumel!ement des galeries captantes et des puits. Un modèle mathématique par éléments finis a été construit pour simuler numériquement le comportement de l'aquifère en régime transitoire. La complexité de la géologie locale a nécessité l'emploi d'une méthode par éléments finis permettant une discrétisatlon 30 souple et détaillée de la zone étudiée, modélisation réalisée avec un maillage fixe en condition de nappe libre. Des développements numériques comprenant la simulation de la surface libre en mode transitoire, ont été introduits dans le modèle LAGATHER du programme LAGAMINE (Université de Liège). Le programme a été testé sur des exemples bidimensionnels avant d'étre appliqué en 30 à l'aquifère de Hesbaye. La discrétisation et les principaux résultats sont présentés.

APA, Harvard, Vancouver, ISO, and other styles

4

Jarrier, Laurent, and Dominique Gentile. "Simulation du comportement thermique transitoire d'un moteur à combustion interne et à allumage commandé." Revue Générale de Thermique 36, no. 7 (1997): 520–33. http://dx.doi.org/10.1016/s0035-3159(97)84035-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Chevreuil, Mathilde, Pierre Ladevèze, and Philippe Rouch. "Une stratégie de calcul en dynamique transitoire recouvrant les basses et moyennes fréquences." European Journal of Computational Mechanics 15, no. 1-3 (2006): 119–30. http://dx.doi.org/10.3166/remn.15.119-130.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Feuillat, François, Jean-René Perrin, René Keller, et al. "Simulation expérimentale de « l'expérience tonneau ». Mesure des cinétiques d'imprégnation du liquide dans le bois et d'évaporation de surface." OENO One 28, no. 3 (1994): 227. http://dx.doi.org/10.20870/oeno-one.1994.28.3.1140.

Full text

Abstract:

Un modèle expérimental miniaturisé a été conçu dans le but de simuler "l'interface tonneau". Les cinétiques de l'imprégnation du liquide dans le bois et de l'évaporation de surface ont été mesurées en conditions de cave (15°C ; 90 p. cent HR) pendant 200 jours sur des petits disques à orientation tangentielle (Ø 63 mm; épaisseur 9 mm) à l'aide d'une méthodologie spécifique. Ces résultats expérimentaux ont été obtenus sur 4 espèces traditionnellement employées en tonnellerie (Quercus robur L., Q. petraea Liebl., Castanea sativa Mill., Robinia pseudacacia L.).L'analyse des cinétiques d'imprégnation et d'évaporation a permis de caractériser les régimes transitoire et permanent (état d'équilibre). Le régime transitoire est dominé par une forte imprégnation pendant les 40 premiers jours environ, qui décroît ensuite de façon asymptotique. Parallèlement, après un temps de latence appelé "retard à l'évaporation", le flux massique devient progressivement une fonction linéaire du temps. Le régime d'équilibre est atteint lorsque le niveau d'imprégnation de la pièce de bois est maximal et constant soit après 140 jours environ (profil d'humidité d'équilibre). Le fonctionnement en régime stationnaire se caractérise alors par un flux d'imprégnation à la face inteme équivalent au flux d'évaporation à la face exteme.Les variations quantitatives des phénomènes sont apparues liées aux conditions de transfert externe (HR de l'air ambiant) et aux conditions de transfert interne (propriétés de la pièce de bois). La comparaison d'échantillons toutes conditions égales par ailleurs a ainsi montré des différences significatives de comportements vraisemblablement liées à la variabilité anatomique du bois (interspécifique, interindividuelle et intraarbre).Cette variabilité pourrait avoir des conséquences sur les phénomènes oxydatifs et sur l'extraction des constituants du bois au cours de l'élevage des vins et des eaux-de-vie en fûts.

APA, Harvard, Vancouver, ISO, and other styles

7

El Khamal, Youssef, Ait Said Brahim, Hachem Aziz, Rabia El Fakir, El Mostafa Mili, and Radouan Mehdaoui. "Modélisation de l’écoulement des eaux souterraines de l’aquifères quaternaire des palmeraies de Figuig et des plaines de Tisserfine, El Arja (Haut Atlas Oriental, Maroc)." European Scientific Journal, ESJ 18, no. 24 (2022): 108. http://dx.doi.org/10.19044/esj.2022.v18n24p108.

Full text

Abstract:

Le présent travail a pour objectif la modélisation hydrodynamique de la nappe Quaternaire de Figuig ; généralement la nappe circule dans des alluvions limoneuses et des calcaires travertineux du Quaternaire avec un substratum imperméable constitué des marnes du Jurassique. La zone d’étude est caractérisée par un climat désertique. La modélisation hydrogéologique a été mise en œuvre par le logiciel MODFLOW. La nappe a été simulée en régime permanent et transitoire ; elle résout l’équation gouvernante de l’écoulement des eaux souterraines en milieux poreux continus et elle calcule la charge hydraulique par simulation des éléments comme : drain, puits, oued, etc. Le modèle numérique ainsi élaboré a permis d’estimer le bilan des aquifères des palmeraies de Figuig et de la plaine de Tisserfine-El Arja dans les deux cas : les conditions actuelles et le scénario de gestion simulant l’élimination des apports des barrages de Sfissif et de Rkiza, par l’oued Tisserfine jusqu’à l’oued Zouzfana.  The current study aims at providing a hydrodynamic model of the Quaternary water aquifer in Figuig; the water aquifer generally flows in a silty alluvial soil and travertine limestone of the Quaternary with an impermeable substratum of the Jurassic marl. The area of the study is characterised by a desert climate. The hydrogeological modelling was carried out using the MODFLOW software. The groundwater was simulated in permanent and transient regime; it solves the governing equation of groundwater flow in continuous porous media and calculates the hydraulic load by simulating elements such as: drain, well, river... Therefore, the digital model developed allowed us to estimate the aquifer balance of Figuig palm groves and Tisserfine-El Arja plain in the two cases: the current conditions and the management scenario simulating the elimination of the inflows from the Sfissif and Rkiza dams, through the Tisserfine wadi to the Zouzfana wadi.

APA, Harvard, Vancouver, ISO, and other styles

8

Chebbah, Lynda, Lakhdar Djemili, Mohammed Tawfik Bouziane, and Mohamed Chiblak. "Modélisation d'un masque en béton bitumineux (brut et protégé) sous sollicitations thermiques en régime transitoire. cas du masque de barrage Ghrib (Ain Defla, Algérie)." La Houille Blanche, no. 1 (February 2020): 42–49. http://dx.doi.org/10.1051/lhb/2019064.

Full text

Abstract:

Le masque en béton bitumineux est l'un des organes les plus utilisés pour l'étanchéité des barrages en remblai. Le parement en béton bitumineux est, en particulier dans le cas des installations de stockage par pompage hydroélectriques, sont souvent très exposé à des fluctuations importantes de température, qui sont causées par la radiation solaire, la variation du niveau d'eau dans le réservoir, par le gel dans la saison d'hiver, ainsi que la vitesse et la direction du vent, sans oublier les précipitations. Pour mieux expliquer le phénomène de transfert de chaleur, il est nécessaire de connaître les variations de température dans les différentes couches du masque en béton bitumineux. Ce travail décrit la mesure de la température dans le masque en béton bitumineux (brut et avec protection) du barrage Ghrib (Ain Defla, Algérie) et son évaluation à l'aide d'un modèle numérique du transfert de chaleur dans le parement en béton bitumineux en utilisant le logiciel Fluent. Dans un premier temps une validation du modèle par comparaison avec des mesures expérimentales, dans le cas d'une variation journalière de température ambiante, La comparaison des résultats du calcul du modèle numérique avec les mesures réelles montre une excellente ressemblance. Nous simulons ensuite la pose d'une protection thermique en ajoutons une couche convective en béton poreux. Les résultats de cette simulation montrent que le transfert de chaleur par convection possède le potentiel de développer une différence de température significative entre les parties inférieure et supérieure du masque, et aussi que l'ajout de cette couche permet d'amortir le pic de température et le réduire à 12,31 °C, ceci de 9 h jusqu'à 15 h au moment où la chaleur est très élevée, ce qui est significatif pour notre masque, où les températures atteignant leurs valeurs maximales (49 °C).

APA, Harvard, Vancouver, ISO, and other styles

9

Agoua, Eusèbe, Sylvain Zohoun, and Patrick Perré. "Utilisation d'une double enceinte pour déterminer le coefficient de diffusion d'eau liée dans le bois en régime transitoire: recours à la simulation numérique pour valider la méthode d'identification." International Journal of Heat and Mass Transfer 44, no. 19 (2001): 3731–44. http://dx.doi.org/10.1016/s0017-9310(01)00022-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

LUCA, DORIN, NARCIS N. POPESCU, and DORIAN D. LUCA. "Simulation of magnetic transitory parameters at electromagnetic forming of metal sheet." Journal of Engineering Sciences and Innovation 5, no. 4 (2020): 363–70. http://dx.doi.org/10.56958/jesi.2020.5.4.7.

Full text

Abstract:

Proposed and accomplished finite element simulations in this paper started from the idea that materials which are plastically deformed and those from which electromagnetic deformation devices are built can influence the development of transitory magnetic phenomenon during the working process. Workpieces from paramagnetic, diamagnetic and ferromagnetic materials and devices that contain metallic and non-metallic materials were taken into study. FLUX2D modelling and simulating software was used to achieve numerical values and graphical images for the main process parameters: magnetic induction and magnetic pressure (of deformation). A finite element model, previously validated through experiment, was used to perform the simulations in order to assure a high degree of accuracy for the presented results.

APA, Harvard, Vancouver, ISO, and other styles

11

MAISSE, G., F. BONNIEUX, B. FAUCONNEAU, et al. "Impacts zootechnique et socio-économique potentiels d’une éventuelle utilisation de la rtGH en salmoniculture." INRAE Productions Animales 6, no. 3 (1993): 167–83. http://dx.doi.org/10.20870/productions-animales.1993.6.3.4197.

Full text

Abstract:

Les salmonidés (Truite et Saumon) sont la principale production piscicole de l’Europe de l’ouest. Les biotechnologies animales intéressant la salmoniculture relèvent de trois domaines : les manipulations génétiques (la triploïdie pour la production de poissons stériles), le transfert de gène (pour produire des poissons résistants aux maladies infectieuses) et les peptides recombinants (vaccins recombinants contre les maladies virales, l’hormone de croissance recombinante de truite -rtGH-). La rtGH a deux effets biologiques principaux : une stimulation de la croissance, en particulier en eau froide, et une amélioration de l’adaptation des juvéniles à l’eau de mer. Un traitement chronique avec la rtGH peut accroître de manière substantielle la production des principaux types de pisciculture. Cependant, il ne peut être réellement pratiqué que dans les exploitations, ayant une haute technicité, qui pratiquent l’oxygénation de l’eau, le contrôle photopériodique de la date de ponte et la gestion informatisée des stocks de poissons. Une simulation des effets d’un traitement par une injection unique de rtGH, pour préparer les juvéniles de Saumon au transfert en mer, montre que le transfert automnal de jeunes saumons traités modifie la période de vente sans augmenter la production. Cependant, si le pisciculteur transfère un premier groupe de poissons traités en automne et un second groupe de poissons naturellement adaptés (smolts) au printemps, la production augmente de 20% et, plus important, la période de vente est allongée. La rentabilité de la production de truites portion semble renforcée et, en considérant uniquement la phase de production, il ne semble pas que la diversification vers le filet ou la grosse truite améliore la rentabilité des piscicultures. L’adoption de la rtGH devrait, à long terme, se traduire par des bénéfices collectifs partagés par les producteurs et les consommateurs. Cependant la phase transitoire est délicate et la voie est très étroite entre la réussite et le rejet. Ce dernier entraînerait une restructuration complète de la branche. La stratégie de la réussite semble bien passer par la diversification et l’amélioration de l’image de marque. Même dans ce cas on peut s’attendre à des effets sur la structure de la branche, certains producteurs bénéficiant plus que d’autre du surplus. Si l’on prend aussi en compte la notion de besoin, la rtGH présente des potentialités non négligeables pour la salmoniculture (meilleure utilisation des matières premières, diminution des rejets) tout autant que des risques (mauvaise image du produit, surproduction, impact sur la structure de la profession). Dans la mesure où son innocuité serait prouvée, la mise en oeuvre de cet outil devrait être progressive, concertée avec les producteurs, et s’accompagner de mesure en faveur de la qualité (label).

APA, Harvard, Vancouver, ISO, and other styles

12

Mosovsky, B. A., and J. D. Meiss. "Transport in Transitory Dynamical Systems." SIAM Journal on Applied Dynamical Systems 10, no. 1 (2011): 35–65. http://dx.doi.org/10.1137/100794110.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Monzón-Verona, José Miguel, Pablo Ignacio González-Domínguez, Santiago García-Alonso, Francisco Jorge Santana-Martín, and Juan Francisco Cárdenes-Martín. "Thermal Analysis of a Magnetic Brake Using Infrared Techniques and 3D Cell Method with a New Convective Constitutive Matrix." Sensors 19, no. 9 (2019): 2028. http://dx.doi.org/10.3390/s19092028.

Full text

Abstract:

In this work we analyse the temperature distribution in a conductor disk in transitory regime. The disk is in motion in a stationary magnetic field generated by a permanent magnet and so, the electric currents induced inside it generate heat. The system acts as a magnetic brake and is analysed using infrared sensor techniques. In addition, for the simulation and analysis of the magnetic brake, a new thermal convective matrix for the 3D Cell Method (CM) is proposed. The results of the simulation have been verified by comparing the numerical results with those obtained by the Finite Element Method (FEM) and with experimental data obtained by infrared technology. The difference between the experimental results obtained by infrared sensors and those obtained in the simulations is less than 0.0459%.

APA, Harvard, Vancouver, ISO, and other styles

14

Petiot, Alain, and Thierry Favre. "Tool Thermal Behavior in SPF Environment." Materials Science Forum 551-552 (July 2007): 111–22. http://dx.doi.org/10.4028/www.scientific.net/msf.551-552.111.

Full text

Abstract:

During a superplastic cycle and part loading/unloading operations, a superplastic tool withstands thermal cycles which affect its life-time, the superplastic cycle time and hence the productivity of the press. A thermal simulation of the tool behavior in superplastic conditions helps to understand which actions could reduce the effects of heat-shields opening/closing and of part loading/unloading on the cooling of the tool and on the heating of the part. Temperature measurements in transitory conditions and in steady-state have been collected on a tool of large dimensions in superplastic conditions of production. The paper will present the correlation between actual measures and simulation in steady state, in slow transitory conditions and in fast transitory conditions.

APA, Harvard, Vancouver, ISO, and other styles

15

Kerger, François, Pierre Archambeau, Sebastien Erpicum, Benjamin J. Dewals, and Michel Pirotton. "Simulation numérique des écoulements mixtes hautement transitoires dans les conduites d'évacuation des eaux." La Houille Blanche, no. 5 (October 2009): 159–66. http://dx.doi.org/10.1051/lhb/2009069.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

DANIS, MICHEL, and MICHEL QUINTARD. "Simulation numérique du comportement d'une nappe aquifère captive: estimation directe des processus transitoires." Hydrological Sciences Journal 32, no. 1 (1987): 105–11. http://dx.doi.org/10.1080/02626668709491165.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Zhang, Peijian, Sheng Qiu, Kunfeng Zhu, and Wensuo Chen. "Novel Low-Loss Reverse-Conducting Insulated-Gate Bipolar Transitor with Collector-Side Injection-Enhanced Structure." Electronics 13, no. 1 (2023): 23. http://dx.doi.org/10.3390/electronics13010023.

Full text

Abstract:

In this paper, a new concept of low-loss Reverse-Conducting Insulated-Gate Bipolar Transistor with Collector-side Injection-Enhanced structure (RC-IGBT-CIE) is proposed and investigated using simulations. In reverse conduction (the on state of the diode mode), the CIE structure enhances the collector-side carrier concentration of the proposed RC-IGBT-CIE, which results in low reverse-conducting voltage (VF). The low reverse recovery loss and low turn-on loss using an inductive load circuit are obtained by using the modified carrier concentration profile resulted from both the CIE effect and the low-injection-efficiency p-emitter. Simulation results show that, with the same sum of turn-on loss and reverse recovery loss (Eon + Erec), when compared to conventional RC-IGBT with anti-parallel thyristor (RC-IGBT-thyristor), the RC-IGBT-CIE reduces VF by 9.2%, and meanwhile, with the same total conducting voltage (Von, sat + VF), the total switching loss (Eoff + Eon + Erec) is reduced by 20.9% but does not sacrifice short-circuit capability.

APA, Harvard, Vancouver, ISO, and other styles

18

Gomez, Ivan, Andrés Gonzalez-Mancera, Brittany Newell, and Jose Garcia-Bravo. "Analysis of the Design of a Poppet Valve by Transitory Simulation." Energies 12, no. 5 (2019): 889. http://dx.doi.org/10.3390/en12050889.

Full text

Abstract:

This article contains the results and analysis of the dynamic behavior of a poppet valve through CFD simulation. A computational model based on the finite volume method was developed to characterize the flow at the interior of the valve while it is moving. The model was validated using published data from the valve manufacturer. This data was in accordance with the experimental model. The model was used to predict the behavior of the device as it is operated at high frequencies. Non-dimensional parameters for generalizing and analyzing the effects of the properties of the fluid were used. It was found that it is possible to enhance the dynamic behavior of the valve by altering the viscosity of the working fluid. Finally, using the generated model, the influence of the angle of the poppet was analyzed. It was found that angle has a minimal effect on pressure. However, flow forces increase as angle decreases. Therefore, reducing poppet angle is undesirable because it increases power requirements for valve actuation.

APA, Harvard, Vancouver, ISO, and other styles

19

Le, Minh Hoang, and Hien Sy Dinh. "Some physical results of single electron transitor." Science and Technology Development Journal - Natural Sciences 1, no. 6 (2018): 206–13. http://dx.doi.org/10.32508/stdjns.v1i6.631.

Full text

Abstract:

Single electron transistor (SET) is a key element in current research area of nanoelectronics and nanotechnology which can offer nano-feature size, low power consumption and high operating speed. SET is a new nanoscale switching device. It can control the motion of the single electron. The goal of this paper is to discuss about some physical properties of the SET and focuses on simulation of basic quantum device characteristics such as tunneling effect, Coulomb blockage, Quantum dot, Coulomb staircase, and Coulomb oscillation. The current-voltage characteristics of SET are explored for illustration. Two types of metallic and semiconducting SETs have been simulated.

APA, Harvard, Vancouver, ISO, and other styles

20

Commault, Jeanne. "Does Consumption Respond to Transitory Shocks? Reconciling Natural Experiments and Semistructural Methods." American Economic Journal: Macroeconomics 14, no. 2 (2022): 96–122. http://dx.doi.org/10.1257/mac.20190296.

Full text

Abstract:

Studies based on natural experiments find that consumption responds strongly and significantly to a transitory variation in income, while semistructural estimations find no pass-through of transitory shocks to consumption. I develop a more robust semistructural estimator that relaxes the assumption that log consumption is a random walk. The robust pass-through estimate is significant and large, implying a yearly marginal propensity to consume of 0.32, close to the natural experiment findings. The robust estimator performs well in numerical simulations of a life cycle model, while nonrobust estimators do not. The difference between the two in the simulations is similar to their difference in the survey data. (JEL D15, E21, J11)

APA, Harvard, Vancouver, ISO, and other styles

21

Chessé, Pascal, Xavier Tauzia, Jean-François Hetet, and Gérald Grosshans. "Simulation des phases de fonctionnement transitoires d'un moteur diesel semi-rapide à suralimentation séquentielle." Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Astronomy 328, no. 3 (2000): 193–98. http://dx.doi.org/10.1016/s1287-4620(00)00122-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Wang, Chenguang. "Transitory speech parts recognition." Speech Communication 7, no. 1 (1988): 98. http://dx.doi.org/10.1016/0167-6393(88)90026-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Nastac, Silviu, Carmen Debeleac, and Cristian Simionescu. "Transitory Dynamics Evaluation inside Driving System of Demolition-Cutting Technological Equipment due to Variable Tool-Material Interactions." Applied Mechanics and Materials 811 (November 2015): 50–56. http://dx.doi.org/10.4028/www.scientific.net/amm.811.50.

Full text

Abstract:

Computational dynamics of technological equipments dealing with intensive, shock-like and various working regimes frames the area of this research paper. A widely used type of demolition-cutting equipment supplied by hydrostatical driving system was adopted, and ordinary scenarios of equipment exploitation have been proposed in order to dignify the very short but strong transitory states deeply depending on the material characteristics and the regime parameters. Elastic, dissipative and plastic components have been considered to compose the global characteristic of the processed material interacting with cutting tool. The authors propose a simplified rheological model intended for modeling and simulation of demolished structural elements based on composite materials, like reinforced concrete. This model is very useful for simulation the variable dynamics of the interaction between the demolition-cutting equipments and the composite elements in order to evaluate the parameters evolution within the process, and obviously, to optimize driving system for minimize transitory effects and vibratory evolutions. The advantage of this computational approach results from the reduced resources involved by simulation tasks, taking into account the global evaluation of the resistant forces usually required for this kind of behavioral analysis.

APA, Harvard, Vancouver, ISO, and other styles

24

Olivo, Adrian, and Juan Toledo. "Electromagnetic model for the study of transitory phenomena associated with atmospheric discharges on transmission lines." ATH 2, no. 5 (2021): 5–28. http://dx.doi.org/10.47460/athenea.v2i5.22.

Full text

Abstract:

The analysis of a research work developed in the company C.V.G CARBONORCA of Venezuela is presented, which has two gas purification plants for the cooking area, designed to purify the gas that comes from the cooking ovens. Each plant is made up of solenoid valves, pneumatic valves, transmitters, process mimic panel and a supervisory system. All these elements are governed by a SIEMENS S5-115U PLC which is in a state of obsolescence, which is why the replacement of these automata by ALLEN BRADLEY ContolLogix automata was designed, in order to guarantee continuity in operations in plant. The research was done with a descriptive design of the field experimental type. A code for each gas treatment plant was obtained in RSLOGIX 5000 v17.00.00 and the update of the database of the supervisory system. The operation of the program was also verified through a simulation of the plant in a supervisory system, the deployment of which was designed for this purpose. Keywords: Automation, Modernization, ControlLogix, Supervisory System, Mimic Panel References [1]M. Uman, D. Mclain and P. Krider. “The Electromagnetic Radiation from a finite antenna” AJP, vol. 43, 1975. 1975. [2]A. Agrawal, H. Price and S. Gurbaxani. “Transient response of multiconductor transmission lines excited by a no uniform electromagnetic field”. IEEE Transactions on electromagnetic compatibility, (2), 119-129. 1980. [3]C. Nucci, F. Rachidi, M. Ianoz and C. Mazzetti. “Comparison of two coupling models for lightning-induced overvoltage calculations”. IEEE Transactions on power delivery, 10(1), 330-339. 1995. [4]R. Thottappillil and M. Uman. “Comparison of lightning return‐stroke models”. Journal of Geophysical Research: Atmospheres, 98(D12), 22903-22914. 1993. [5]K. Yee. “Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media”, IEEE Transactions on Antennas and Propagation, vol. AP-14, no. 3, pp. 302–307, May 1966. 1966. [6]A. Taflove and S. Hagness. “Computational Electrodynamics: The Finite-Difference Time-Domain Method”. Boston-London: 2005. [7]A. Elsherbeni and V. Demir. “The finite-difference time-domain method for electromagnetics with MATLAB simulations”. The Institution of Engineering and Technology. 2016. [8]V. Silva. “Aplicação do método FDTD para avaliação da resposta de linhas de transmissão e aterramentos elétricos frente a descargas atmosféricas”. Dissertação de Mestrado, Universidade federal de minas gerais. Belo Horizonte, Brasil. 2017. [9]T. Noda and S. Yokoyama. “Thin wire representation in finite difference time domain surge simulation”. IEEE Transactions on Power Delivery, 17(3), 840-847. 2002. [10]R. Chamié-Filho. Análise de tensões induzidas em linhas de distribuição de baixa tensão frente a uma descarga atmosférica. 2009. [11]R. Jiménez. “Lightning Induced Voltages on Overhead Lines above Non-Uniform and Non-Homogeneous Ground” Doctoral dissertation, Universidad Nacional de Colombia-Sede Medellín. 2014. [12]S. Visacro and A. Soares. “HEM: A model for simulation of lightning-related engineering problems”. IEEE Transactions on power delivery, 20(2), 1206-1208. 2005. [13]J. Herrera. “Nuevas aproximaciones en el cálculo de tensiones inducidas por descargas eléctricas atmosféricas”. Programa de Doctorado en Ingeniería Eléctrica, Facultad de Ingeniería, Departamento de Ingeniería Eléctrica y Electrónica, Universidad Nacional de Colombia, Bogotá, 128 . 2006. [14]C. McAfee. “Lightning return stroke electromagnetics-time domain evaluation and application” Doctoral dissertation. 2016. [15] S. Gedney. “Introduction to the finite-difference time-domain (FDTD) method for electromagnetics”. Synthesis Lectures on Computational Electromagnetics, 6(1), 1-250. 2011. [16]Y. Taniguchi, Y. Baba, N. Nagaoka and A. Ametani. “An improved thin wire representation for FDTD computations”. IEEE Transactions on Antennas and Propagation, 56(10), 3248-3252. 2008. [17]E. Soto. “Cálculo de campo electromagnético producido por rayo para terreno no plano y su efecto en las tensiones inducidas en líneas de distribución”. Tesis de Maestría, Universidad Nacional de Colombia. Manizales, Colombia. 2010. [18]D. Sullivan. “Electromagnetic simulation using the FDTD method”. John Wiley & Sons. 2013.

APA, Harvard, Vancouver, ISO, and other styles

25

Delessy, Henri, Frédéric Lerais, Sébastien Paris-Horvitz, and Henri Sterdyniak. "Après Maastrich : quelles politiques économiques en Europe ?" Revue de l'OFCE 43, no. 1 (1993): 273–305. http://dx.doi.org/10.3917/reof.p1993.43n1.0273.

Full text

Abstract:

Résumé Le Traité de Maastricht pose avec acuité le problème de l'organisation de la politique économique en Europe, tant en ce qui concerne la phase de transition, qu'en ce qui concerne le fonctionnement d'une zone à monnaie unique. Sur le fond, deux points de vue s'opposent : pour les uns, la construction de l'Europe doit permettre la renaissance d'une politique économique active tournée vers la croissance. Pour les autres, au contraire, l'Europe doit être libérale. Les accords de Maastricht optent très clairement pour une politique économique « vertueuse », notamment en adoptant des critères rigoureux de dettes et de déficits publics et en mettant en place une Banque centrale indépendante. Les accords prévoient une phase transitoire durant laquelle la politique économique des différents pays sera dictée par la nécessité de satisfaire aux conditions qui permettront d'accéder à l'UEM. Cette phase intervient dans une période où les perspectives de croissance sont déjà médiocres. Actuellement, 10 pays sur 12 ne satisfont pas ces conditions et devraient pratiquer une politique économique plus restrictive. Ceci est difficilement justifiable pour certains pays qui, malgré une dette publique importante, ont un solde extérieur excédentaire. Ces critères imposent de plus une politique économique pro-су clique. L 'ajustement budgétaire requis par une application stricte des critères est extrêmement fort pour certains pays : 7, 5 points de PIB en Italie, 7 points en Belgique et en Grèce, 2,5 points en Irlande. Une simulation, réalisée à l'aide du modèle MIMOSA, montre que, si les pays concernés mettaient en œuvre une politique représentant la moitié de ce qui ést nécessaire, le taux décroissance du PIB de la CE serait plus bas de 0,3 % environ chacune des trois premières années et son niveau resterait inférieur de 1,4% à son niveau du compte central en 1999. Pour les pays concernés, cette politique aurait un effet récessif important ; l'objectif d'une dette publique à 60% du PIB en 1999 reste hors d'atteinte. La manière dont est organisée la convergence laisse mal augurer de l'organisation de la politique économique dans l'Union européenne. Le Traité prévoit une Banque centrale européenne (ВСЕ) indépendante, chargée avant tout de la stabilité des prix. La France ne retrouvera pas une influence sur sa politique monétaire mais l'abandonnera à des partisans de politiques rigoureuses. Les pays n'auront plus à leur disposition les armes du taux d'intérêt et du taux de change, mais n'auront plus à se soucier directement de leur solde extérieur, ni à craindre les anticipations défavorables des spéculateurs. Il y a là un degré de liberté utile mais aussi un risque potentiel que chaque pays pratique une politique trop expansionniste. En réaction, le Traité impose des limites contraignantes à la dette et au déficit publics, sans tenir assez compte des considérations conjoncturelles ou structurelles, qui peuvent rendre nécessaire que ces barrières soientfranchies, temporairement ou durablement. L 'accord de Maastricht peut contribuer à terme à impulser la croissance en Europe, mais, dans son état actuel, il ne prévoit pas une coordination satisfaisante de la politique économique en Europe entre la ВСЕ responsable de la politique monétaire et les treize détenteurs de pouvoir budgétaire. De nouveaux accords, instituant la coordination de l'ensemble des instruments de politiques économiques, sont donc nécessaires. On ne pourra faire l'économie d'un débat de fond sur l'organisation et les objectifs de /apolitique économique en Europe.

APA, Harvard, Vancouver, ISO, and other styles

26

Lotzmann, Ulf, Michael Möhring, and Klaus G. Troitzsch. "Simulating Normative Agents." International Journal of Agent Technologies and Systems 2, no. 1 (2010): 31–49. http://dx.doi.org/10.4018/jats.2010120103.

Full text

Abstract:

The article discusses the sociological background and the general features of a new simulation toolbox, which was explicitly designed to describe, design and simulate multi-agent systems whose component agents are endowed with the capability to exchange norm invocations and to internalize norms, to develop codes of norms and to change them. This toolbox takes into account that normative behavior can only originate in the interpretation of norm invocations and the deliberate decision to abide by the emerging norms—otherwise what emerges is only a transitory regularity. Agents designed with the help of this toolbox are endowed with initial rule sets that they can vary over time, according to the experience gained.

APA, Harvard, Vancouver, ISO, and other styles

27

Moisan, Noël, Jean-Marie Floc’h, and Jacques Citerne. "Simulation des régimes transitoires sur des sections de lignes microruban par une technique de filtrage numérique." Annales des Télécommunications 41, no. 9-10 (1986): 511–18. http://dx.doi.org/10.1007/bf02998754.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Triki, Ali, and Ezzeddine Hadj Taïeb. "Simulation numerique des écoulements transitoires à surface libre provoqués par la superposition de manœuvres de vannes." La Houille Blanche, no. 3 (July 2010): 71–80. http://dx.doi.org/10.1051/lhb/2010037.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

del Amo Sancho, Alejandro. "Solar Trigeneration: a Transitory Simulation of HVAC Systems Using Different Typologies of Hybrid Panels." Journal of Sustainable Development of Energy, Water and Environment Systems 2, no. 1 (2014): 1–14. http://dx.doi.org/10.13044/j.sdewes.2014.02.0001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Benjumea, J. M., J. Sánchez-Oneto, J. R. Portela, F. J. Jiménez-Espadafor, and E. J. Martínez de la Ossa. "Simulation of supercritical water oxidation reactor in transitory state: Application to time-dependent processes." Journal of Supercritical Fluids 117 (November 2016): 219–29. http://dx.doi.org/10.1016/j.supflu.2016.06.021.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Haj Kacem, Yassine, and Ezzedine Hadj-Taieb. "Simulation numérique par éléments finis des écoulements transitoires gaz-liquide dans les conduites rigides et quasi-rigides." La Houille Blanche, no. 5 (October 2017): 69–78. http://dx.doi.org/10.1051/lhb/2017047.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Reyes Caro, María Camila, Paula Alejandra Córdoba Narváez, and Edwin Rivas Trujillo. "Análisis de estabilidad transitoria y de pequeña señal en un sistema multimáquina: caso de estudio." Revista vínculos 15, no. 2 (2018): 129–38. http://dx.doi.org/10.14483/2322939x.13685.

Full text

Abstract:

En este artículo se presenta el análisis de estabilidad transitoria y de pequeña señal para un sistema multimáquina. Se parte de los datos de la red propuesta por El-Abiad y Nagappan y los resultados del estudio de estabilidad transitoria obtenidos mediante el segundo método de Lyapunov, los cuales se comparan con la respuesta del sistema en DIgSILENT PowerFactory 15.1; se ejecuta la función RMS/EMS simulation que permite definir las curvas t-δ, perfiles de velocidad, tensión y frecuencia. Adicionalmente, se incluye el estudio de pequeña señal con la función modal analysis que tiene el fin de conocer el comportamiento del sistema ante pequeñas perturbaciones por medio del lugar geométrico de la raíz (LGR); este análisis permite una visión más amplia a los problemas de estabilidad para sistemas robustos que deben soportar fallas durante su operación o implementarse nuevas técnicas para la coordinación de protecciones.

APA, Harvard, Vancouver, ISO, and other styles

33

Rubio-Arellano, Ana B., Jose A. Ramos-Leal, Víctor M. Vázquez-Báez, and José I. Rodriguez Mora. "Modeling the Groundwater Dynamics of the Celaya Valley Aquifer." Water 15, no. 1 (2022): 1. http://dx.doi.org/10.3390/w15010001.

Full text

Abstract:

We propose a hydrodynamic simulation model to understand the piezometric operation of the Celaya Valley aquifer. The aquifer is located at the east of Guanajuato State in México. Our proposed model reproduces, under transitory conditions, the performance of the aquifer during the dry season from year 2015 to 2019 and the rainy season from year 2010 to 2015. The simulation was projected for the two seasons up to eleven years ahead and considering only three simulation scenarios (one should bear in mind that there are a number of different and interesting scenarios): trend, pump reduction and pump increase. In general terms, the model accurately reproduces the natural conditions of the aquifer. It is necessary to continue taking measures for the preservation of water; similarly, it is suggested to continue monitoring the aquifer piezometric levels to update the model based on data availability.

APA, Harvard, Vancouver, ISO, and other styles

34

McCulloch, Neil, and Bob Baulch. "Simulating the impact of policy upon chronic and transitory poverty in rural Pakistan." Journal of Development Studies 36, no. 6 (2000): 100–130. http://dx.doi.org/10.1080/00220380008422656.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Bruzzone, Luca, Pietro Fanghella, and Mario Baggetta. "Experimental Assessment of Fractional-Order PDD1/2 Control of a Brushless DC Motor with Inertial Load." Actuators 9, no. 1 (2020): 13. http://dx.doi.org/10.3390/act9010013.

Full text

Abstract:

The application of Fractional Calculus to control mechatronic devices is a promising research area. The most common approach to Fractional-Order (FO) control design is the PIλDµ scheme, which adopts integrals and derivatives of non-integer order λ and µ. A different possible approach is to add FO terms to the PID control, instead of replacing integer order terms; for example, in the PDD1/2 scheme, the half-derivative term is added to the classical PD. In the present paper, by mainly focusing on the transitory behaviour, a comparison among PD, PDµ, and PDD1/2 control schemes is carried out, with reference to a real-world mechatronic implementation: a position-controlled rotor actuated by a DC brushless motor. While using a general non-dimensional approach, the three control schemes are first compared by continuous-time simulations, and tuning criteria are outlined. Afterwards, the effects of the discrete-time digital implementation of the controllers are investigated by both simulation and experimental tests. The results show how PDD1/2 is an effective and almost cost-free solution for improving the trajectory-tracking performance in position control of mechatronic devices, with limited computational burden and, consequently, easily implementable on most commercial motion control drives.

APA, Harvard, Vancouver, ISO, and other styles

36

Baillet, L., V. Linck, S. D’Errico, B. Laulagnet, and Y. Berthier. "Finite Element Simulation of Dynamic Instabilities in Frictional Sliding Contact." Journal of Tribology 127, no. 3 (2005): 652–57. http://dx.doi.org/10.1115/1.1866160.

Full text

Abstract:

This paper describes tools for numerical modeling which enable the understanding of the appearance of vibrations of a structure generated by the frictional contact between two bodies (the excitation source being friction). The dynamic finite element code PLASTD is used to reproduce transitory phenomena generated at the contact interface. This code includes contact and friction algorithms based upon a formulation which uses Lagrange multipliers. A numerical study of the dynamic response of a 2D mechanical model composed of a deformable body in relative translation and unilateral contact with Coulomb friction with a rigid surface is presented. The steady sliding solution is generically unstable and leads to a dynamic response which leads to the generation of instabilities characterized by the appearance of steady-state pulses. It is important to notice that those instabilities appear even with a constant friction coefficient of Coulomb. These simulations provided the local contact conditions (kinematics, tribological state, contact stresses, etc). The kinematics shows the existence of local impacts and sliding at high frequencies. Furthermore, local contact normal stress is found to be much higher than that expected for a smooth surface. Finally, a 3D simulation of brakes is carried out, focusing on the vibrations of the disk and the brake pad which produce noise and are due to the interface instabilities.

APA, Harvard, Vancouver, ISO, and other styles

37

Nowak, Stefan, Johannes Neidhart, Ivan G. Szendro, and Joachim Krug. "Multidimensional Epistasis and the Transitory Advantage of Sex." PLoS Computational Biology 10, no. 9 (2014): e1003836. http://dx.doi.org/10.1371/journal.pcbi.1003836.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Hernández-Pérez, Miguel Angel, Gustavo Delgado-Reyes, Vicente Borja-Jaimes, Jorge Salvador Valdez-Martínez, and Marisol Cervantes-Bobadilla. "An Adaptation of a Sliding Mode Classical Observer to a Fractional-Order Observer for Disturbance Reconstruction of a UAV Model: A Riemann–Liouville Fractional Calculus Approach." Mathematics 11, no. 24 (2023): 4876. http://dx.doi.org/10.3390/math11244876.

Full text

Abstract:

This paper proposes a modification of a Sliding Mode Classical Observer (SMCO) to adapt it to the fractional approach. This adaptation involves using a set of definitions based on fractional calculus theory, particularly the approach developed by Riemann–Liouville, resulting in a Sliding Mode Fractional Observer (SMFO). Both observers are used to perform disturbance reconstruction considered additive in a Quadrotor Unmanned Aerial Vehicle (UAV) model. Then, this work presents the fractional-order sliding mode observer’s mathematical formulation and integration into the Quadrotor UAV model. To validate the quality of the disturbance reconstruction process of the proposed SMFO observer scheme, numerical simulations are carried out, where a reconstruction quality indicator (BQR) is proposed based on the analysis of performance indices such as the Mean Square Error (MSE), the First Probability Moment (FPM), and Second Probability Moment (SPM), which were obtained for both the SMCO and the SMFO. The simulation results demonstrate the efficacy of the proposed observer in accurately reconstructing disturbances under various environmental conditions. Comparative analyses with SMCO highlight the advantages of the fractional-order approach in terms of reconstruction accuracy and improvement of its transitory performance. Finally, the presented SMFO offers a promising avenue for enhancing the reliability and precision of disturbance estimation, ultimately contributing to the advancement of robust control strategies for Quadrotor UAV systems.

APA, Harvard, Vancouver, ISO, and other styles

39

Cárdenas, María Luz. "Are the transitory enzyme-enzyme complexes found in vitro also transitory in vivo? If so, are they physiologically important?" Journal of Theoretical Biology 152, no. 1 (1991): 111–13. http://dx.doi.org/10.1016/s0022-5193(05)80522-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Tamene, Youcef, Said Abboudi, and Cherif Bougriou. "Simulation des transferts thermiques transitoires à travers un mur multicouche soumis à des conditions de flux solaire et de convection." Journal of Renewable Energies 12, no. 1 (2023): 117–24. http://dx.doi.org/10.54966/jreen.v12i1.125.

Full text

Abstract:

On propose une étude numérique, par différences finies, du transfert de chaleur dans un mur multicouche (à deux ou trois couches) soumis à une condition de rayonnement solaire sur le côté extérieur et prenant en compte les échanges de chaleur par convection sur ses deux faces. L’exploitation du code numérique est développée sur des cas relatifs au problème posé dans l’habitat. Les résultats numériques sont présentés sur des exemples de matériaux utilisés dans le domaine du bâtiment dans des conditions réelles de fonctionnement (flux solaire, pertes convectives, etc…). On analyse également, l’influence, sur le transfert de chaleur, de quelques paramètres clés du système comme le choix des matériaux, l’optimisation de leur épaisseur et également la nature variable du flux solaire. Une proposition optimale sera dégagée de cette étude en fonction des objectifs recherchés.

APA, Harvard, Vancouver, ISO, and other styles

41

Hwang, Sun Ho. "Analyzing Nonlinear Income Persistence of the Elderly." Korean Data Analysis Society 25, no. 4 (2023): 1351–62. http://dx.doi.org/10.37727/jkdas.2023.25.4.1351.

Full text

Abstract:

This study estimates income risk observed among the elderly using the Korean Retirement and Income Study data. In order to decompose household income into permanent and transitory components, the quantile-based panel data framework is employed. The permanent component is assumed to follow a first-order Markov process, and the transitory component is assumed to be independent over time and also independent of the persistent components. I estimate the income persistence from the estimated permanent income component, and analyze the dynamic effects of permanent income shocks on income through simulations. The results show the presence of nonlinear persistence in the household income of the elderly. Furthermore, it is observed that the dynamic effects of permanent income shocks vary depending on the past income history. These findings differ from studies focused on the age groups participating in the labor market. In particular, the permanent income shocks have a significant impact on the income of elderly households. In particular, the permanent income shocks have a significant impact on the income of elderly households.

APA, Harvard, Vancouver, ISO, and other styles

42

Tyszkowska-Kasprzak, Elżbieta. "Niepokój o wartości we współczesnej antyutopii rosyjskiej." Kultura Słowian Rocznik Komisji Kultury Słowian PAU 19 (December 22, 2023): 55–68. http://dx.doi.org/10.4467/25439561ksr.23.004.18981.

Full text

Abstract:

Concerns for Values in the Contemporary Russian Anti-utopia Utopia as a literary genre gains popularity in transitory moments, periods of social, economic and mental transformations. Literary visions of the future can be treated as forecasts of the development of societies, or projections of dreams about a better tomorrow, but in the case of anti-utopias, these predictions are not optimistic and have their source in the reality contemporary to the author. The abundance of dystopias in the early 21st century testifies to writers’ concerns about the development of the country and society. The main theme of the latest anti-utopias is undoubtedly the problem of limiting or even depriving an individual of freedom, but the writers also showed particular concern for the future of Russia as a state, its territorial integrity, culture and special spirituality. Both the future autonomy of the country and its indivisibility were quite often questioned, and fears or even phobias were associated with the vision of the threat of Chinese colonisation.

APA, Harvard, Vancouver, ISO, and other styles

43

Sawadogo, Wenddabo Olivier, and Blaise Somé. "MATHEMATICAL MODELING AND NUMERICAL SIMULATION IN TRANSITORY MODE OF GROUNDWATER LEVEL IN THE PLAIN OF SOUROU (BURKINA FASO)." Far East Journal of Applied Mathematics 94, no. 1 (2016): 17–36. http://dx.doi.org/10.17654/am094010017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Anghel, Dan Alexandru, Andreea Rodica Sterian, and Paul E. Sterian. "Modeling Quantum Well Lasers." Mathematical Problems in Engineering 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/736529.

Full text

Abstract:

In semiconductor laser modeling, a good mathematical model gives near-reality results. Three methods of modeling solutions from the rate equations are presented and analyzed. A method based on the rate equations modeled in Simulink to describe quantum well lasers was presented. For different signal types like step function, saw tooth and sinus used as input, a good response of the used equations is obtained. Circuit model resulting from one of the rate equations models is presented and simulated in SPICE. Results show a good modeling behavior. Numerical simulation in MathCad gives satisfactory results for the study of the transitory and dynamic operation at small level of the injection current. The obtained numerical results show the specific limits of each model, according to theoretical analysis. Based on these results, software can be built that integrates circuit simulation and other modeling methods for quantum well lasers to have a tool that model and analysis these devices from all points of view.

APA, Harvard, Vancouver, ISO, and other styles

45

Fan, Hong Ming, Kai Yuan He, Zhi Fang Yin, and Dan Zhang. "Transient Numerical Simulation for Air Distribution of Air Conditioning and Ventilation in Subway Island-Platform." Advanced Materials Research 250-253 (May 2011): 3107–14. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.3107.

Full text

Abstract:

The typical subway island-platform of Beijing as research object was present in the article. Taking two-equation turbulence model and giving boundary conditions of piston wind and train heat load change with the time, adopting numerical method simulates air distribution of air-conditioning and ventilation system in subway. The results indicate that piston wind effect has significant impact on the area of platform entrance and staircase entrance while station with safety doors can obstruct piston effect at a certain degree. Simultaneity, the supply- exhaust air system offers relatively uniform temperature and velocity field, which meets requirements of transitory comfort for passengers. It is found that numerical simulation method can simulate and forecast air distribution of air conditioning and ventilating system in subway station. In conclusion, it can provide the reference for optimizing air-conditioning and ventilation system, improving thermal environment designing of subway station.

APA, Harvard, Vancouver, ISO, and other styles

46

Hadriche, Abir, Ichrak Behy, Amal Necibi, Abdennaceur Kachouri, Chokri Ben Amar, and Nawel Jmail. "Assessment of Effective Network Connectivity among MEG None Contaminated Epileptic Transitory Events." Computational and Mathematical Methods in Medicine 2021 (December 28, 2021): 1–14. http://dx.doi.org/10.1155/2021/6406362.

Full text

Abstract:

Characterizing epileptogenic zones EZ (sources responsible of excessive discharges) would assist a neurologist during epilepsy diagnosis. Locating efficiently these abnormal sources among magnetoencephalography (MEG) biomarker is obtained by several inverse problem techniques. These techniques present different assumptions and particular epileptic network connectivity. Here, we proposed to evaluate performances of distributed inverse problem in defining EZ. First, we applied an advanced technique based on Singular Value Decomposition (SVD) to recover only pure transitory activities (interictal epileptiform discharges). We evaluated our technique’s robustness in separation between transitory and ripples versus frequency range, transitory shapes, and signal to noise ratio on simulated data (depicting both epileptic biomarkers and respecting time series and spectral properties of realistic data). We validated our technique on MEG signal using detector precision on 5 patients. Then, we applied four methods of inverse problem to define cortical areas and neural generators of excessive discharges. We computed network connectivity of each technique. Then, we confronted obtained noninvasive networks to intracerebral EEG transitory network connectivity using nodes in common, connection strength, distance metrics between concordant nodes of MEG and IEEG, and average propagation delay. Coherent Maximum Entropy on the Mean (cMEM) proved a high matching between MEG network connectivity and IEEG based on distance between active sources, followed by Exact low-resolution brain electromagnetic tomography (eLORETA), Dynamical Statistical Parametric Mapping (dSPM), and Minimum norm estimation (MNE). Clinical performance was interesting for entire methods providing in an average of 73.5% of active sources detected in depth and seen in MEG, and vice versa, about 77.15% of active sources were detected from MEG and seen in IEEG. Investigated problem techniques succeed at least in finding one part of seizure onset zone. dSPM and eLORETA depict the highest connection strength among all techniques. Propagation delay varies in this range [18, 25]ms, knowing that eLORETA ensures the lowest propagation delay (18 ms) and the closet one to IEEG propagation delay.

APA, Harvard, Vancouver, ISO, and other styles

47

Berne, C., A. Pasturel, M. Sluiter, and B. Vinet. "Ab initiostudy of transitory metastable phases solidified by drop-tube processing." Modelling and Simulation in Materials Science and Engineering 8, no. 3 (2000): 233–37. http://dx.doi.org/10.1088/0965-0393/8/3/303.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Singh, Chandra, David Garofalo, and Benjamin Lang. "Powerful Jets from Radiatively Efficient Disks, a Decades-Old Unresolved Problem in High Energy Astrophysics." Galaxies 9, no. 1 (2021): 10. http://dx.doi.org/10.3390/galaxies9010010.

Full text

Abstract:

The discovery of 3C 273 in 1963, and the emergence of the Kerr solution shortly thereafter, precipitated the current era in astrophysics focused on using black holes to explain active galactic nuclei (AGN). But while partial success was achieved in separately explaining the bright nuclei of some AGN via thin disks, as well as powerful jets with thick disks, the combination of both powerful jets in an AGN with a bright nucleus, such as in 3C 273, remained elusive. Although numerical simulations have taken center stage in the last 25 years, they have struggled to produce the conditions that explain them. This is because radiatively efficient disks have proved a challenge to simulate. Radio quasars have thus been the least understood objects in high energy astrophysics. But recent simulations have begun to change this. We explore this milestone in light of scale-invariance and show that transitory jets, possibly related to the jets seen in these recent simulations, as some have proposed, cannot explain radio quasars. We then provide a road map for a resolution.

APA, Harvard, Vancouver, ISO, and other styles

49

Rodríguez de Gracia, Hilario. "Corrupción en la gobernanza chilena de Gabriel Cano Aponte (1715-1733) y Manuel Silvestre de Salamanca (1734-1737)." Historia y Genealogía, no. 13 (December 11, 2023): 7–36. http://dx.doi.org/10.21071/hyg.vi13.16762.

Full text

Abstract:

Este artículo contiene un amplio abanico de datos biográficos sobre dos gobernadores de Chile. Ambos nacían en Mora (Toledo) y estaban unidos por lazos de consanguinidad. Gabriel Cano fue un militar con una excepcional hoja de servicio en las guerras que mantuvo España en Europa durante el reinado de Carlos II y continuó apoyando a Felipe V en la guerra de Sucesión. Manuel Silvestre fue su sobrino y sucesor en el gobierno y presidencia de la Audiencia chilena; algo que iba a ser transitorio, pero que se prolongó tres largos años. En el proceso de formación, dio sus primeros pasos estudiantiles en la Universidad de Alcalá, aunque pronto se incorporó al ejército y, acabado el conflicto bélico sucesorio, optó por acompañar a su familiar a las Indias. Para reconstruir las actividades y actos gubernativos de ambos al frente del gobierno chileno hay numerosas aportaciones bibliográficas, en especial trabajos de historiadores del país andino que profundizan en numerosos aspectos de la vida pública del tío y sobrino. Con la ayuda de otros documentos de archivo ha sido posible perfeccionar ambas biografías y resaltar ciertos aspectos tanto de sus vivencias personales como de su actividad profesional todavía ignorados.

APA, Harvard, Vancouver, ISO, and other styles

50

Beylunioğlu, Fuat C., M. Ege Yazgan, and Thanasis Stengos. "DETECTING CONVERGENCE CLUBS." Macroeconomic Dynamics 24, no. 3 (2018): 629–69. http://dx.doi.org/10.1017/s1365100518000391.

Full text

Abstract:

The convergence hypothesis, which is developed in the context of growth economics, asserts that the income differences across countries are transitory, and developing countries will eventually attain the level of income of developed ones. On the other hand, convergence clubs hypothesis claim that the convergence can only be realized across groups of countries that share some common characteristics. In this study, we propose a new method to find convergence clubs that combines a pairwise method of testing convergence with maximum clique and maximal clique algorithms. Unlike many of those already developed in the literature, this new method aims to find convergence clubs endogenously without depending on a-priori classifications. In a Monte Carlo simulation study, the success of the method in finding convergence clubs is compared with a similar algorithm. Simulation results indicated that the proposed method perform better than the compared algorithm in most cases. In addition to the Monte Carlo, a new empirical evidence on the existence of convergence clubs is presented in the context of real data applications.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Simulation transitoire'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles