Search results for "process"
showing 10 items of 22310 documents
Modelling flow and heat transfer in spacer-filled membrane distillation channels using open source CFD code
2013
Abstract A good understanding of the details of hydrodynamic and heat transport conditions and their impact on temperature polarisation and pressure drops is essential for optimum design of membrane distillation (MD) modules. To this end, the present work reports on initial progress in the development of a tool for 3D simulation of spacer-filled MD channels based on the open source CFD code library OpenFOAM. The paper discusses a number of modelling and implementation aspects including model geometry and computational domain, choice of boundary conditions, and discretisation schemes. The results pertaining to the effect of three different spacer types on the fluid dynamics and heat transfer…
Friction and Heat Transfer in Membrane Distillation Channels: An Experimental Study on Conventional and Novel Spacers
2022
The results of an experimental investigation on pressure drop and heat transfer in spacer-filled plane channels, which are representative of Membrane Distillation units, are presented and discussed. Local and mean heat transfer coefficients were obtained by using Thermochromic Liquid Crystals and Digital Image Processing. The performances of a novel spacer geometry, consisting of spheres that are connected by cylindrical rods, and are hereafter named spheres spacers, were compared with those of more conventional woven and overlapped spacers at equal values of the Reynolds number Re (in the range ~150 to ~2500), the pitch-to-channel height ratio, the flow attack angle and the thermal boundar…
Space-Time Forecasting of Seismic Events in Chile
2017
The aim of this work is to study the seismicity in Chile using the ETAS (epidemic type aftershock sequences) space‐time approach. The proposed ETAS model is estimated using a semi‐parametric technique taking into account the parametric and nonparametric components corresponding to the triggered and background seismicity, respectively. The model is then used to predict the temporal and spatial intensity of events for some areas of Chile where recent large earthquakes (with magnitude greater than 8.0 M) occurred.
Integreating geological and seismological data in point process models for seismical analysis
2017
Nowadays in the seismic and geological fields, large and complex data sets are available. This information is a valuable source that can be used for improving the seismic hazard assessment of a given region. In particular, the integration of geologic variables into point process models to study seismic pattern is an open research field that has not been fully explored. In this work, we present several open-access datasets (the catalogue of the earthquakes, geological information such as faults, plate boundary and the presence of volcanoes) that are properly treated to describe the seismicity of events occurred in Greece between 2005 and 2014. We use these datasets to fit an advanced spatial…
Models and methods for space and space-time interactions in complex point processes with applications on earthquakes
Local methods for complex spatio-temporal point processes
2022
Joint second-order parameter estimation for spatio-temporal log-Gaussian Cox processes
2018
We propose a new fitting method to estimate the set of second-order parameters for the class of homogeneous spatio-temporal log-Gaussian Cox point processes. With simulations, we show that the proposed minimum contrast procedure, based on the spatio-temporal pair correlation function, provides reliable estimates and we compare the results with the current available methods. Moreover, the proposed method can be used in the case of both separable and non-separable parametric specifications of the correlation function of the underlying Gaussian Random Field. We describe earthquake sequences comparing several Cox model specifications.
Weighted local second-order statistics for complex spatio-temporal point processes
2019
Spatial, temporal, and spatio-temporal point processes, and in particular Poisson processes, are stochastic processes that are largely used to describe and model the distribution of a wealth of real phenomena. When a model is fitted to a set of random points, observed in a given multidimensional space, diagnostic measures are necessary to assess the goodness-of-fit and to evaluate the ability of that model to describe the random point pattern behaviour. The main problem when dealing with residual analysis for point processes is to find a correct definition of residuals. Diagnostics of goodness-of-fit in the theory of point processes are often considered through the transformation of data in…
El nost Milan: il rap dei ‘nuovi italiani', tra riappropriazioni urbane e rivendicazioni identitarie
2019
italianoFin dai suoi esordi, la cultura hip-hop e stata attraversata da una forte connotazione in senso spaziale, che ne ha variamente contraddistinto i diversi elementi. La citta post-industriale, specie lungo i suoi margini e nei suoi interstizi, rappresenta infatti un sito cruciale a partire dal quale la storia ma, soprattutto, la geografia del rap sono andate col tempo costruendosi. Obiettivo di questo articolo e di riflettere criticamente sulla relazione fra rap e spazi urbani in Italia alla luce delle complesse costruzioni culturali, sociali e politiche che la sottendono, con particolare riferimento a due rapper milanesi della cosiddetta generazione dei nuovi italiani, Zanko e Ghali. …