Search results for " impianti"

Bubble formation at variously inclined nozzles

2014

Bubble formation at variously inclined submerged nozzles, fed with a continuous gas flow rate, is investigated. Results confirm previous findings, such as a substantial independence of bubble size of nozzle diameter and its dependence on the cubic root of gas flow rate at sufficiently high values of this parameter. Nozzle inclination in the range between 0 and 135° from the vertical upward orientation is found to have a negligible effect on bubble size. Observed bubble rise velocities lead to an estimation of the average liquid velocity induced by bubbles motion, leading in turn to a very simple correlation for the estimation of the liquid velocities induced by the repeated passage of bubbl…

Free surface oxygen transfer in large aspect ratio unbaffled bio-reactors, with or without draft-tube

2015

Abstract It is widely accepted that animal cell damage in aerated bioreactors is mainly related to the bursting of bubbles at the air–liquid interface. A viable alternative to sparged bioreactors may be represented by uncovered unbaffled stirred tanks, which have been recently found to be able to provide sufficient mass transfer through the deep free surface vortex which takes place under agitation conditions. As a matter of fact, if the vortex is not allowed to reach impeller blades, no bubble formation and subsequent bursting at the free-surface, along with relevant cells damage, occurs. In this work oxygen transfer performance of large aspect ratio unbaffled stirred bioreactors, either e…

Fuzzy environmental analogy index to develop environmental similarity maps for designing air quality monitoring networks on a large-scale

2019

All activities aimed at studying the primary causes and effects of air pollution cannot disregard the fact that it is necessary to have an optimal air quality monitoring network for assessing population exposure to air pollution and predicting the magnitude of the health risks. In the framework of a cooperation between the ARPA Sicilia Organization and the Department of Engineering, University of Palermo, research was performed to develop an innovative methodology useful for defining environmental similarity maps aimed at supporting the design of air quality monitoring networks at the regional scale. This approach is based on a new index called the fuzzy environmental analogy index (FEAI) b…

A multifunctional plant for a sustainable reuse of marble waste toward circular economy

2021

The marble processing cycle involves the production of large quantities of wastes whose disposal represents an economic and environmental concern for marble companies due to the difficulty of identifying suitable landfills and the high transfer costs. In this context, the design of a sustainable industrial plant that allows the reuse of the calcium carbonate (CaCO3) contained in the marble waste is extremely challenging. With this recognition, the main industrial applications of CaCO3 are firstly analyzed in the present work to identify the physical–chemical properties required to CaCO3 in these contexts. Later, different plant solutions are suggested to recover CaCO3 from marble sludge in…

A dempster-shafer theory-based approach to compute the birnbaum importance measure under epistemic uncertainty

2016

Importance Measures (IMs) aim at quantifying the contribution of components to the system performance. In Process Risk Assessment (PRA), they are commonly used by risk managers to derive information about the risk/safety significance of events. However, IMs are typically calculated without taking into account the uncertainty that inevitably occurs whenever the input reliability data are poor. In literature, uncertainty arising from the lack of knowledge on the system/process parameters is defined as epistemic or subjective uncertainty. The present work aims at investigating on its influence on the Birnbaum IM and on how such an uncertainty could be accounted for in the components ranking. I…

On the effects of the Double-Walled Tubes lay-out on the DEMO WCLL breeding blanket module thermal behavior

2019

Abstract The EU-DEMO Water-Cooled Lithium Lead Breeding Blanket (WCLL BB) concept foresees liquid Pb-15.7Li eutectic alloy as breeder and neutron multiplier, whereas pressurized subcooled water as coolant, with operative conditions typical of the PWR fission reactors (temperature in the range of 295–328 °C and pressure of 15.5 MPa). The cooling down of the BB is guaranteed by means of two separated cooling circuits: the one consisted in square channels housed within the complex of Side Walls and First Wall, and the one composed of a set of Double-Walled Tubes (DWTs) submerged in the Breeding Zone (BZ) and deputed to remove heat power therein generated. A parametric thermal study has been ca…

Parametric study of the influence of double-walled tubes layout on the DEMO WCLL breeding blanket thermal performances

2020

Abstract Within the framework of the EUROfusion activities regarding the EU-DEMO Breeding Blanket (BB) concept, the University of Palermo is long-time involved, in close cooperation with ENEA, in the design of the Water Cooled Lithium Lead (WCLL) BB, that is one of the two concepts under consideration for the DEMO reactor. It is mainly characterized by a liquid lithium-lead eutectic alloy acting as breeder and neutron multiplier, as well as by subcooled pressurized water flowing as coolant under PWR-like conditions (pressure of 15.5 MPa and inlet/outlet temperatures of 295 °C/328 °C). A research campaign has been recently carried out to study the potential influence of the Breeding Zone coo…

ANALISI DI RISCHIO DELL’IMPIANTO SPERIMENTALE “SELECTIVE PRODUCTION OF EXOTIC SPECIES” (SPES) DELL’INFN DI LEGNARO

Il progetto di ricerca denominato EURISOL (European Isotope Separation On-Line Radioactive Ion Beam Facility), che vede coinvolti i principali laboratori di ricerca nucleari europei, è rivolto allo studio di progettazione e fattibilità di un impianto per la produzione di fasci di nuclei radioattivi posizionati nella cosiddetta “terra incognita” della carta dei nuclidi. Lo scopo principale è l’esplorazione della materia esotica (nuclei caratterizzati da un eccesso difetto di neutroni), con le sue possibili implicazioni nell’ambito della ricerca di base della fisica nucleare, nelle applicazioni in campo medico e dell’astrofisica, e ancora nello studio dei materiali utilizzati nei reattori nuc…

Progettazione e sviluppo del software R.A.D. per analisi FMECA

2012

Ad oggi l’analisi FMECA (Failure Modes, Effects and Criticality Analysis) si è dimostrata uno strumento di indagine molto utile per lo studio dell’affidabilità dei componenti dei vari sistemi di un impianto. Tuttavia, l’applicazione sistematica di tale metodologia, anche nel caso di impianti relativamente semplici, risulta onerosa in termini di risorse necessarie ai fini della sua conduzione e gestione. A supporto dell’analisi, esiste una buona varietà di software sviluppati per lo scopo, tuttavia spesso essi presentano alcune funzionalità selettive essendo dedicati all’impiego in ambiti specifici. Alla luce di tale limitazione si è pensato di realizzare e mettere a punto un software sempli…

Controlled solution-based fabrication of perovskite thin films directly on conductive substrate

2021

Abstract Organometallic perovskites are one of the most investigated materials for high-efficiency thin-film devices to convert solar energy and supply energy. In particular, methylammonium lead iodide has been used to realize thin-film perovskite solar cells, achieving an efficiency higher than 20%. Different fabrication procedures based on the spin-coating technique have been proposed, which do not ensure homogenous morphologies. In this work, we present a scalable process to fabricate methylammonium lead iodide thin films directly on conductive substrates, consisting of electrodeposition and two subsequent chemical conversions. A thorough investigation of the morphological, structural an…