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Numerical simulators for modeling one- and multi-dimensional multiphase transport and biodegradation
Get PDFThe research topic of this tesis, i.e., studying the coupling of multiphase flow and biodegradation, did not fit perfectly with the model already available, in the sense that not all the features needed were already implemented. Thus, the following choices have been made. On the one hand, an easy-to-use and easy-to-modify one-dimensional simulator for two-phase flow plus biodegradation was developed for preliminary and basic studies. On the other hand, an available multiphase flow simulator was selected and modified for introducing the same biodegradation module developed for the one-dimensional code
Monitoraggio di alcuni eventi di precipitazione intensa verificatisi in Sardegna mediante stima da immagini METEOSAT nell’infrarosso
Get PDFLa presente relazione riassume l’attività svolta dai ricercatori del SAR e del CRS4 nell’ambito di una collaborazione scientifica volta allo studio e all’applicazione di metodologie, per il monitoraggio e la previsione di eventi di precipitazione intensa e la conseguente diramazione di allerta tempestivi. In particolare vengono qui riassunti i risultati ottenuti applicando alcune tecniche di stima delle precipitazioni al suolo mediante immagini Meteosat nel canale dell’infrarosso a tre eventi di precipitazione particolarmente intensa verificatisi in Sardegna negli ultimi due anni. Il contenuto di questa relazione è stato oggetto di una presentazione mediante poster al meeting annuale dell’European Geophysical Society che si è tenuto a Nizza nel marzo del 2001
A conceptual framework for multi-modal interactive virtual workspaces
Get PDFConstruction projects involve a large number of both direct stakeholders (clients, professional teams, contractors, etc.) and indirect stakeholders (local authorities, residents, workers, etc.). Current methods of communicating building design information can lead to several types of difficulties (e.g. incomplete understanding of the planned construction, functional inefficiencies, inaccurate initial work or clashes between components, etc.). Integrated software solutions based on VR technologies can bring significant value improvement and cost reduction to the Construction Industry. The aim of this paper is to present research being carried out in the frame of the DIVERCITY project (Distributed Virtual Workspace for Enhancing Communication within the Construction Industry - IST project n°13365), funded under the European IST programme (Information Society Technologies). DIVERCITY's goal is to develop a Virtual Workspace that addresses three key building construction phases: (1) Client briefing (with detailed interaction between clients and architects); (2) Design Review (which requires detailed input from multidisciplinary teams - architects, engineers, facility managers, etc.); (3) Construction (aiming to fabricate or refurbish the building).Using a distributed architecture, the DIVERCITY system aims to support and enhance concurrent engineering practices for these three phases allowing teams based in different geographic locations to collaboratively design, test and validate shared virtual projects. The global DIVERCITY project will be presented in terms of objectives and the software architecture will be detailed.149-162Pubblicat
FEMME: fluid-dynamics engineering montecarlo method environment
Get PDFA new software platform based on the particle transport and Montecarlo techniques is described. The code, named FEMME, is a new portable environment that’s naturally integrated with the in house fluid dynamics RUNS code of CRS4 (KARALIS). This code permits to simulate physical problems associate to the fluid motion that depends on the lagrangian displacement of particles in the fluid. Pratically developed an hybrid algorithm particle-finite-volume to join the Reynolds averaged Navier Stokes equations and Montecarlo transport equations , to solve particular and complex fluid dynamics problem joined to reactive or turbulent flows. The first application carried out is concerned with the Rubbia’s Project 242. Other field of application may be related to combustion problems, to improvement of turbulence modeling, as well as to the transport of passive scalars in environmental and geophysical applications
Assessment and formulation of data assimilation techniques for a 3D Richards equation-based hydrological model
Get PDFThe main objectives of de DAUFIN project are: to develop a unifying modeling framework applicable at the catchment scale and based on rigorous conservation equations for the study of hydrological processes in the stream channel, land surface, soil, and groundwater components of a river basin; to implement data assimilation methodologies within this modeling framework and for other control models to enable the optimal use of remote sensing, ground-based, and simulation data; to test and apply the models and the data assimilation methods at various catchment scales, including hillslopes and subcatchment of the Ourthe water shed in Belgium and the entire Meuse river basin, one of the major basins in Europe with a drainage area of 33000 km² that comprises the Ourthe
Three-dimensional reconstruction and visualization of the cerebral cortex in primates
Get PDFWe present a prototype interactive application for the direct analysis in three dimensions of the cerebral cortex in primates. The paper provides an overview of the current prototype system and presents the techniques used for reconstructing the cortex shape from data derived from histological sections as well as for rendering it at interactive rates. Results are evaluated by discussing the analysis of the right hemisphere of the brain of a macaque monkey used for neuroanatomical tract-tracing experiments.147-15
Thermal analysis of the TOF lead target at CERN
Get PDFThe lead target at the Time Of Flight (TOF) facility at CERN, currently under
commissioning, undergoes relevant temperature transients due to the intensity of the
four 20 GeV/c pulses of 7 x 1012 protons, carrying an energy of 21.4 kJ delivered in 7 ns
each. A 3D thermal analysis of the target system in both steady-state and transient conditions has been performed using the finite volume commercial code StarCD coupled with the results from Fluka simulations.
Results show that the maximum temperature inside the lead target using the parameters
of the TOF commissioning phase (4 pulses every 1.2 s in a 14.4 s super-cycle) is 127°C
at steady-state operations, which is an acceptable value, compatible with safe and
durable target operations. A significant improvement could be obtained by doubling the
beam size (108°C maximum temperature in the bulk of the central block).
The transients coming from the pulsed operation are not such as to create structural
problems related to thermal fatigue. It is interesting to notice that the thermal
oscillation in the hottest point in the bulk of the central block is much lower in the case
where the 4 pulses are spaced of 3.6 s during the PS super-cycle (about 20°C), than in
the case where they are spaced of only 1.2 s (about 40° C)
Preliminary description of a hillslope-storage Boussinesq model for subsurface and overland flow
Get PDFThe Boussinesq model for subsurface flow in an idealized sloping aquifer has recently been extended to hillslopes of arbitrary geometry by incorporating the width function w(s) into the governing equation, were x is the distance along the length of the hillslopes. The resulting mathematical model can be simplified if three higher order terms containing (1/w)w’(x) are dropped. In this preliminary report we describe the model along with some characteristic hillslopes that will be used to test it and develop it further
A parallel spectral element method for applications to computational mechanics
No full textWe present a fully unstructured, parallel spectral element method based on domain decomposition. The implementation aims at improving accuracy and performance of a large number of applications in computational mechanics. We accomplish this target by merging the high accuracy of spectral methods with the flexibility of finite elements in treating problems with complex geometry. Parallelism is coarse grain and exploited at the algebraic level: the global linear system is distributed among processors, and then solved by iterative techniques. For evolutive problems it is possible to adopt explicit time-marching schemes, thus resulting in very competitive performances. We provide a couple of numerical experiments, based on the Helmholtz equation and the acoustic problem, and give a measure of accuracy and efficiency, illustrating the method in both steady and evolutive problems