Search results for "flows"
showing 10 items of 148 documents
El sistema regional andaluz de los servicios avanzados (SA) con los distintos sectores económicos
2002
El artículo estudia la caracterización del entorno productivo de los SA a través de la creación de espacio relacional. El objetivo es medir su nivel tecnológico, el del espacio productivo andaluz y conocer en qué fase de la sociedad servindustrial se encuentra. Las empresas de gestión de calidad y de consultoría son las que concentran el mayor número de servicios comprados frente a los Organismos Públicos de Investigación (OPIs) que suministran el grueso de la I+D a los sectores económicos. Gran parte de la contratación de los SA y de la cooperación se realiza a escala regional, pero la densidad de relaciones es baja y poco contínua. Se trata de un sistema regional fragmentado. This paper s…
Solid sediment transport in turbulent channel flow over irregular rough boundaries
2017
Abstract The presence of a loading of dispersed particles in a turbulent flow affects the dynamics of the carrier flow field which, in turn, drives grains movement. The focus of the paper is on the analysis of the coupling effects between near-bed turbulence structures and the dynamics of dispersed suspended solid particles in wall-bounded turbulent multiphase flows. We consider turbulent horizontal channel flows bounded by rough boundaries. The friction Reynolds number of the unladen flow is R e τ = 180 and the dispersed phase spans one order of magnitude of particle diameter. To analyze sedimentation and suspended phase transport, we adopt concepts and modeling ideas derived from the Eule…
Discussion on "Free overfall in inverted semicircular channels" by Subhasih Dey
2004
This discussion focalizes on the applicability of the free overfall as a measuring device in open channel flows depending on the accuracy of the stage-discharge relationship
X-ray emission mechanisms in protostellar jets
2005
Prompted by the recent detection of X-ray emission from Herbig-Haro objects, we studied the interaction between a supersonic jet originating from a young stellar object and the ambient medium; our aim is to investigate the mechanisms causing the X-ray emission. Our model takes into account the radiative losses from optically in plasmas and Spitzer's thermal conduction including saturation effects. We explored the parameter space defined by the density contrast between the ambient medium and the jet and by the Mach number, to infer the configurations which can give rise to X-ray emission. From the models, we derived the X-ray emission as it would be observed with Chandra/ACIS-I and XMM-Newto…
A Chain of Words as an Introduction: Human Dignity, Language, Identity, Citizenship, Values, Human Capital and Urban Spaces
2022
To analyze the issue of cities-migrants interactions, as well as social-monetary values interactions, it is necessary to place it in a “higher” context, in order not to risk losing the necessary connection with universal ethical principles, and in a “broader” one, in which understanding complexity on a global scale interprets local conditions. The study of migration flows and urban dynamics, as well as housing markets, through theoretical paradigms and scientific tools from different disciplines provides an opportunity to learn and compare, dialogue and interface with new keys to understanding the problem, or with alternative interpretations and unprecedented perspectives in the path of mul…
Local gas-liquid hold-up and interfacial area via light sheet and image analysis
2010
Particle Image Velocimetry techniques coupled with advanced Image Processing tools are receiving an increasing interest for measuring flow quantities and local bubble-size distributions in gas-liquid contactors. In this work, an effective experimental technique for measuring local gas hold-up and interfacial area, as well as bubble size distribution, is discussed. The technique, hereafter referred to as Laser Induced Fluorescence with Shadow Analysis for Bubble Sizing (LIF-SABS) is based on laser sheet illumination of the gas-liquid dispersion and synchronized camera, i.e. on equipment typically available within PIV set-ups. The liquid phase is made fluorescent by a suitable dye, and an opt…
A decoupled method for solving distribution networks with PV nodes
2009
In this paper, a methodology for the load flow solution of distribution systems with fixed voltage nodes (PV nodes) is presented. The proposed technique is the extension of a methodology already set up by the authors to solve distribution systems; it is an iterative approach devoted to the treatment of voltage dependent loads; at each iteration, all the network components (lines, loads, and PV nodes) are represented by resistances and reactances. The methodology is based on the identification of two networks that are solved in sequence, thus allowing the attainment of state features of the original system. One of the two systems is made up only of shunt and series resistances; the other onl…
Conclusioni
2012
La macroecomia della finanza ha ridotto i vincoli di libertà delle nazioni in assenza di una codificazione delle regole condivise da tutti i partecipanti al sistema economico internazionale. La dimensione spaziale della crescita, invece, è probabilmente una risposta adatta ai processi di cambiamento in atto e complementare alle risposte fino ad oggi fornite. La marginalità per lo sviluppo regionale, ovvero l’ampia utilizzazione di giacimenti economici, individuali, innovativi poco esplorati, assume un valore strategico perché rivaluta, nell’ambito dei processi di cambiamento economico, l’importanza dei contesti regionali e locali nei loro diversi ambiti. sfida e una scelta per il cambiament…
The nearest X-ray emitting protostellar jet (HH 154) observed with Hubble
2008
Context. The jet coming from the YSO binary L1551 IRS5 is the closest astrophysical jet known. It is therefore a unique laboratory for studies of outflow mechanisms and of the shocks occurring when expanding material hits the ambient medium as well as of how the related processes influence the star- (and planet-) forming process. Aims. The optical data are related to other data covering the spectrum from the optical band to X-rays with goal of understanding the energetics of low-mass star jets, in general, and of this jet in particular. We study the time evolution of the jet, by measuring the proper motions of knots as they progress outwards from the originating source. Methods. The nebulos…
Isotropic stochastic flow of homeomorphisms on Sd for the critical Sobolev exponent
2006
Abstract In this work, we shall deal with the critical Sobolev isotropic Brownian flows on the sphere S d . Based on previous works by O. Raimond and LeJan and Raimond (see [O. Raimond, Ann. Inst. H. Poincare 35 (1999) 313–354] and [Y. LeJan, O. Raimond, Ann. of Prob. 30 (2002) 826–873], we prove that the associated flows are flows of homeomorphisms.