Search results for "flu"
showing 10 items of 16583 documents
Derivation of a Homogenized Two-Temperature Model from the Heat Equation
2014
This work studies the heat equation in a two-phase material with spherical inclusions. Under some appropriate scaling on the size, volume fraction and heat capacity of the inclusions, we derive a coupled system of partial differential equations governing the evolution of the temperature of each phase at a macroscopic level of description. The coupling terms describing the exchange of heat between the phases are obtained by using homogenization techniques originating from [D. Cioranescu, F. Murat: Coll\`ege de France Seminar vol. 2. (Paris 1979-1980) Res. Notes in Math. vol. 60, pp. 98-138. Pitman, Boston, London, 1982.]
Многофазные решения нелокальных симметричных редукций уравнений иерархии АКНС: общий анализ и простейшие примеры
2020
Рассмотрены нелокальные симметрии, которыми обладают все или все четные (все нечетные) уравнения из иерархии АКНС. Построены примеры решений, удовлетворяющих одновременно нескольким нелокальным уравнениям из иерархии АКНС. Проведено подробное исследование однофазных решений.
Anwendungen in Hydro- und Aerodynamik
1949
Wie in der Theorie der Hydrodynamik gezeigt wird, konnen die Geschwindigkeitskomponenten der stationaren Stromung einer reibungslosen inkompressiblen Flussigkeit durch Differentiation einer der Laplaceschen Differentialgleichung genugenden Ortsfunktion u (des Geschwindigkeitspotentials) nach den Koordinaten des Aufpunktes erhalten werden. Ist insbesondere die Stromung zweidimensional, d. h. z. B. nur von den rechtwinkligen Koordinaten x und y abhangig, so stellt die zum Geschwindigkeitspotential u (x, y) konjugierte Funktion v (x, y) die sogenannte Stromfunktion dar. Die Kurven u (x, y) = konstant stellen die Niveaulinien, diejenigen v (x, y) = konstant die Stromlinien der betrachteten Stro…
Collisions moléculaires en phase gazeuse
2019
L’étude théorique des collisions entre atomes et molécules permet, grâce à la résolution d’état à état des simulations numériques basées sur la physique quantique, une description détaillée des mécanismes mis en jeu et contribue grandement à améliorer les modèles atmosphériques et astrophysiques. Dans cet article, après avoir présenté les méthodes de dynamique actuelles, nous donnons des exemples clés d’intérêt pour le milieu interstellaire, l’atmosphère terrestre et les milieux (ultra)froids, et présentons les défis majeurs à relever.
Potentialités des lasers à fibre dans la génération de rayonnement cohérent UV
2006
Le premier laser a fibre dope aux ions de terres rares fonctionna au tout debut des annees 60. Il fournissait quelques milliwatts autour de 1 μm. Les decades suivantes virent tres peu d'ameliorations tant du cote des laboratoires que du point de vue industriel. La derniere decennie (1995/2005) vit se concretiser la seconde revolution des lasers a fibres. Deja kilowatt en continu, ils atteignent desormais les 10 13 watts/cm 2 avec des impulsions de la centaine de femtoseconde. Lors de cette presentation nous passerons en revue les potentialites des lasers a fibre. Nous decrirons les verrous technologiques qui ont ete leves ces dix dernieres annees pour les regimes CW mais aussi femtosecondes…
Analysis of the specific common competences of the Degree Courses in Speech Therapy and on the ability to apply in the didactic systems
2020
Law 11 January 2018 n. 3 places the attention of the Health Professions on the specific common skills, which must be evident in the didactic systems to protect the Profession. The purpose of this work is to identify which skills are always present among the training objectives of the Degree Courses in Speech Therapy, and which instead become "specific" for our profession. The data analysis was conducted on 27 Degree Courses in Speech Therapy present in Italy, using the portal "Universitaly" and evaluating the SUA cards of the various Degree Courses. The analysis of the data revealed that: basic skills were insufficient for the areas of labor law and corporate organization; transversal skill…
Controlled turbulence regime of electron cyclotron resonance ion source for improved multicharged ion performance
2020
Fundamental studies of excitation and non-linear evolution of kinetic instabilities of strongly nonequlibrium hot plasmas confined in open magnetic traps suggest new opportunities for fine-tuning of conventional electron cyclotron resonance (ECR) ion sources. These devices are widely used for the production of particle beams of high charge state ions. Operating the ion source in controlled turbulence regime allows increasing the absorbed power density and therefore the volumetric plasma energy content in the dense part of the discharge surrounded by the ECR surface, which leads to enhanced beam currents of high charge state ions. We report experiments at the ECR ion source at the JYFL accel…
Effect of space charge on the negative oxygen flux during reactive sputtering
2017
Negative ions often play a distinctive role in the phase formation during reactive sputter deposition. The path of these high energetic ions is often assumed to be straight. In this paper, it is shown that in the context of reactive magnetron sputtering space charge effects are decisive for the energetic negative ion trajectories. To investigate the effect of space charge spreading, reactive magnetron sputter experiments were performed in compound mode with target materials that are expected to have a high secondary ion emission yield (MgO and CeO2). By the combination of energy flux measurements, and simulations, a quantitative value for the negative oxygen ion yield can be derived.
Irradiation effects in CaF2probed by Raman scattering
2016
The formation conditions and dynamics of Ca colloids and point defects that appear in irradiated single crystals of CaF2 were investigated by Raman spectroscopy. The intensity changes in the Raman spectra because of the presence of different concentrations of point defects and Ca colloids that emerged in CaF2 after irradiation with 2.2 GeV Au ions were used to study their distribution and stability under illumination with three laser wavelengths (473, 532 and 633 nm) at different output powers (2 to 200 mW). A damage saturation at a fluence of 6 × 1011 ion cm−2 was observed. The dependence of the spectral changes on the ion fluence can be described by a core/halo damage cross-section model.…
Analytical description of solid particles kinematics due to a fluid flow and application to the depiction of characteristic kinematics in cold sprayi…
2017
Abstract In several multiphase flow applications such as fluidization, thermal spraying, atomization manufacturing and so on, the Newton's law is widely enacted to formulate the particle/fluid kinematic interaction and then to compute particles kinematics. This paper provides analytical solutions of the Newton's law in its time-dependent formulation or simplified formulation, the latter being a reduction of the time dependent problem into a spatial description of the particle motion. It was found that the velocity solution is strictly similar in both cases so that the simplified formulation is viable. The W_ 1 branch of the Lambert's function yields the analytical particle residence time an…