61,155 research outputs found
UN RITRATTO ALLO SPECCHIO - PORTRET U OGLEDALU - A PORTRAIT IN THE MIRROR
No full textLa biografia dell'artista Milena Pavlovic Barilli consente di gettare luce sul suo lavoro diviso tra produzione di opere d'arte e grafica pubblicitaria nel settore del lusso e della moda. Le vicende personali si intrecciano con quelle professionali contribuendo a spiegare scelte ed esiti artistici dell'artista italo serba precocemente scomparsa a New York nel 1945 all'età di 36 anni
VENEZIA SUBSIDENCE MONITORING SERVICE IN THE LAGOON OF VENICE FOR REGIONAL ADMINISTRATIVE AND WATER AUTHORITIES DATA USER PROGRAMME (DUP), II PERIOD Executive Summary
No full textThe scope of the project “VENEZIA - Subsidence monitoring service in the Lagoon of Venice for regional administrative and water authorities” was to define and implement a land subsidence monitoring service in the Lagoon of Venice for regional and administrative authorities. In order to provide the best knowledge of the land subsidence process around the Lagoon of Venice, SAR-based monitoring techniques (differential SAR interferometry and interferometric point target analysis) were integrated with levelling and GPS surveys into an overall information system.
Land subsidence due to natural and anthropogenic causes has represented one of the most serious environmental problems for the Lagoon of Venice and its catchment (Tosi et al., 2002, Carbognin and Tosi, 2003, Carbognin et al., in press). Land subsidence has increased the vulnerability and the geological hazard (i.e. river flooding, riverbank stability, intrusion of seawater in the aquifer system, deteriorating of the littoral sectors with a general coastline regression and an increment of the sea bottom slope close to the shoreline) of these areas, a large portion of which lies below the mean sea level. After the regulation of groundwater exploitation from the Venetian aquifer-aquitard system, a remarkable slowing down of the induced subsidence in Marghera (industrial zone), in the historical center of Venice and along the littorals was ascertained in the 1970’s. Recent studies (Carbognin and Tosi, 2003) have shown that land subsidence is still in progress in the southern and northern coastal areas and in the nearby mainland, where groundwater is extracted from artesian wells, thicker and more compressible Holocene sediments are present, and organic soil oxidation takes place in reclaimed areas.
Until 1999, levelling of the Venice region was carried out only along the coast and the lagoon edges and the monitoring network was composed by benchmarks along single levelling lines; a fine grid network was established only in the city of Venice. In recent years, the levelling network has been updated to cover all the southern part of the Lagoon, and plans exist to cover also the northern sector. The same network used for the levelling surveys is also considered for differential GPS measurements. In addition to these ground-based methods, differential SAR interferometry using long series of SAR data (Wegmüller and Strozzi, 1998; Strozzi et al, 2001) and interferometric point target analysis (IPTA) (Wegmüller et al., 2003, Werner et al., 2003) have emerged as very promising tools for the monitoring of land subsidence at high spatial resolution.
The VENEZIA project was organized along a service definition phase, a service implementation phase and a service quality assessment phase. Important elements of the project were the definition, implementation and validation of the service for interferometric point target analysis and the integration of the SAR-based monitoring techniques with levelling and GPS surveys into an overall information system capable to provide the best knowledge of the subsidence process to the authorities that manage the Po Plain area around the Lagoon of Venice.Gamma Remote Sensing; Istituto di Scienze Marine - Consiglio Nazionale delle Ricerche; ESA-ESRINPublished6A. Monitoraggio ambientale, sicurezza e territorioope
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
Large-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
Valutazione sull'efficacia dell'alimentazione parenterale in chirurgia tramite il monitoraggio della pseudo-colinesterasi (CHE)
No full textEnergy dissipation and flux laws for unsteady turbulence
No full textDirect Numerical Simulations of spatially periodic unsteady turbulence show that the high Reynolds number scalings of the instantaneous energy dissipation rate and interscale energy flux at intermediate wavenumbers are qualitatively different from the well-known cornerstone scalings of equilibrium turbulence where and are time-dependent rms velocity and integral length-scales. Instead, they both scale as where and are length and velocity scales characterizing initial/overall unsteady turbulence conditions
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
Real-space Manifestations of Bottlenecks in Turbulence Spectra
No full textAn energy-spectrum bottleneck, a bump in the turbulence spectrum between the inertial and dissipation ranges, is shown to occur in the non-turbulent, one-dimensional, hyperviscous Burgers equation and found to be the Fourier-space signature of oscillations in the real-space velocity, which are explained by boundary-layer-expansion techniques. Pseudospectral simulations are used to show that such oscillations occur in velocity correlation functions in one- and three-dimensional hyperviscous hydrodynamical equations that display genuine turbulence
Braid Entropy of Faraday Waves driven 2D Turbulence
No full textWe report new experimental results that use tools from braid theory to characterize two-dimensional turbulent flows driven by Faraday waves. The average topological length of the material fluid lines is found to grow exponentially with time. It allows us to compute the braid’s topological entropy SBraid. We show that SBraid increases as the square root of the turbulence kinetic energy E ~ u^2, where u^2 is the horizontal velocity variance . At long times, the PDFs of Lbraid are positively skewed and present strong exponential tails
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