Search results for "IMPIANTI"
showing 10 items of 797 documents
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…
Improved FMECA for effective risk management decision making by failure modes classification under uncertainty
2022
Failure Mode, Effects, and Criticality Analysis (FMECA) is a proactive reliability and risk management technique extensively used in practice to ensure high system performance by prioritising failure modes. Owing to the limitations of traditional FMECA, multi-criteria decision-making methods have been employed over the past two decades to enhance its effectiveness. To consider the vagueness and uncertainty of the FMECA evaluation process, an interval-based extension of the Elimination et Choice Translating Reality (ELECTRE) TRI method is proposed in the present paper for the classification of failure modes into risk categories. Therefore, ratings of failure modes against risk parameters are…
Trattamento dell'incertezza epistemica nell'analisi affidabilistica
Safety studies of a hydrogen refuelling station: Determination of the occurrence frequency of the accidental scenarios
2009
At present, the hydrogen vehicles technology appears to have future Prospective for reduction in greenhouse gas emissions. Nevertheless, the development of such a technology requires appropriate infrastructures for production, Storage and refuelling stages in a refuelling station. This one presents safety challenges due to the hydrogen chemicophysical characteristics. So, to avoid hazards, it is necessary to implement safety practices that, if early adopted in the development of a fuelling station project, can allow very low impact, safety being incorporated in the project itself. However, a drawback is the not sufficient experience and the scarcity of the relevant data collection. To deepe…
Epistemic uncertainty in fault tree analysis approached by the evidence theory
2012
Abstract Process plants may be subjected to dangerous events. Different methodologies are nowadays employed to identify failure events, that can lead to severe accidents, and to assess the relative probability of occurrence. As for rare events reliability data are generally poor, leading to a partial or incomplete knowledge of the process, the classical probabilistic approach can not be successfully used. Such an uncertainty, called epistemic uncertainty, can be treated by means of different methodologies, alternative to the probabilistic one. In this work, the Evidence Theory or Dempster–Shafer theory (DST) is proposed to deal with this kind of uncertainty. In particular, the classical Fau…
Coupling of electromembrane processes with reverse osmosis for seawater desalination: Pilot plant demonstration and testing
2022
Reverse osmosis (RO) is the most widespread technology to produce drinking water from seawater (SW). However, the integration of different membrane processes offers interesting alternatives. In this work, electromembrane processes were integrated with RO to desalinate real seawater in a pilot plant with 25 m3/day capacity. Electrodialysis (ED, either two-stage or single stage), shortcut reverse electrodialysis (scRED) and assisted reverse electrodialysis (ARED) pre-desalinated seawater before RO with the ED-ED-RO, ED-RO, and scRED-ARED-RO process schemes. Treated wastewater was used as salt sink in the scRED-ARED tests. The performance of the pilot plant can be summarized as follows: water …
Numerical simulation of the transient thermal-hydraulic behaviour of the ITER blanket cooling system under the draining operational procedure
2015
Abstract Within the framework of the research and development activities supported by the ITER Organization on the blanket system issues, an intense analysis campaign has been performed at the University of Palermo with the aim to investigate the thermal-hydraulic behaviour of the cooling system of a standard 20° sector of ITER blanket during the draining transient operational procedure. The analysis has been carried out following a theoretical-computational approach based on the finite volume method and adopting the RELAP5 system code. In a first phase, attention has been focused on the development and validation of the finite volume models of the cooling circuits of the most demanding mod…
Analysis of steady state thermal-hydraulic behaviour of the DEMO Divertor cassette body cooling circuit
2017
Abstract Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. A comparative evaluation study has been performed considering the two different options under consideration for the divertor cassette body coolant, namely subcooled pressurized water and helium. The research activity has been carried out following a theoretical-computational approach based on the finite volume method and adopting a qualified Computational Fluid-Dynamic (CFD) code. CFD analy…