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Adaptive Sampling Limit Surface Search Application to Identify Cliff-Edge Effects in Severe Accident Uncertainty Analysis
No full textSevere accident (SA) codes and their core degradation models have to deal with strongly nonlinear and discontinuous phenomena. In the application of uncertainty quantification to SA simulations, the combination of such phenomena may lead to a strong increase in the uncertainty propagated through the simulation, as well as to the chaotic behavior of the output variables. In this framework, the application of the limit surface search method of the RAVEN tool is proposed for a case where cliff-edge effects of SA phenomena determine a bifurcation of an output figure of merit. The algorithm is based on a predictive method making use of a support vector machine model, and it is applied with the aim of separating those input values that lead to different phenomenologies among the uncertainty calculations. The case study is in regard to the uncertainty analysis of the ASTEC code simulation of the QUENCH6 experimental test conducted in the framework of the International Atomic Energy Agency Coordinated Research Project I31033
Stampa a compressione di materiali compositi laminati realizzati con TNT di carbonio da riciclo pre-impregnati
Full text linkIn questo rapporto si presenta lo studio relativo alla realizzazione di pannelli laminati ottenuti a partire da strati di tessuto non tessuto (TNT) pre-impregnati costituiti da fibre di carbonio da riciclo mediante stampa a compressione. Sono state prese in considerazione tre tipologie di pre-impregnati commerciali, differenti per grammatura di fibre, da cui sono stati ricavati un certo numero di strati che, opportunamente sovrapposti, sono stati inseriti in uno stampo di acciaio. Tale stampo, inserito in una pressa idraulica, è stato portato alla giusta temperatura. Successivamente è stata applicata un’opportuna forza, che tenuta per un adeguato intervallo di tempo, ha permesso, la completa polimerizzazione della resina, ed il consolidamento dei diversi strati tra loro. Parametri come la temperatura delle piastre della pressa, la forza applicata e il tempo di tenuta in pressione sono stati ottimizzati per ottenere le caratteristiche desiderate dei pannelli laminati. Successivamente i pannelli sono stati tagliati con tecnologia water-jet per ricavare provini in numero e dimensioni tali da effettuare le successive prove di caratterizzazione. Sono stati tagliati provini in direzioni perpendicolari per valutare le prestazioni del materiale composito ottenuto in entrambe le direzioni. I test meccanici effettuati sui provini al fine di valutare la qualità del materiale ottenuto hanno riguardato prove di impatto e test di trazione statica. Inoltre, nel lavoro svolto sono stati avviati studi sulla porosità del materiale ottenuto mediante due metodologie differenti per le informazioni fornite: osservazioni al microscopio ottico delle sezioni dei pannelli e processo di digestione. I risultati riportati in questo studio sono la base di partenza per ulteriori studi futuri che non potranno non considerare anche le caratteristiche del processo di fabbricazione del materiale composito preimpregnato di partenza per avere una valutazione completa del risultato ottenuto dalla stampa a compressione.In this work a study on the production of laminated panels obtained from pre-impregnated nonwoven fabric (NWF) layers made of recycled carbon fibers by compression molding is presented. In particular, by using a steel mold, a specific number of layers were stacked considering three types of commercial pre-impregnated materials with different fibers weight. The complete resin polymerization and the consolidation of the different layers are obtained by using a hydraulic press, with appropriate parameters such as temperature, applied force and time. This work describes the optimization of process parameters in order to obtain the desired characteristics of the laminated panels. Subsequently, the panels were cut with water-jet technology to obtain appropriate size specimens to carry out the characterization tests. Samples were cut in perpendicular directions to evaluate the performance of the composite material. The mechanical tests carried out in order to evaluate the material quality involved impact tests and static tensile tests. Furthermore, the porosity of the specimens is observed using two different methodologies: optical microscopy and digestion process. The results reported in this study are the starting point for further future studies that will have to consider the characteristics of the manufacturing process of the pre-impregnated composite material to have a more comprehensive evaluation of compression molding
Flow instabilities in helical-coil steam generators for small modular reactors: A review
No full textThis study covers the research and discoveries in two-phase flow-boiling instabilities available in the literature—specifically for a helical-coil steam generator (HCSG), including experimental findings, theoretical research, computational models, and system code analyses—supporting research and development of representative small modular reactors (SMRs). Like other new and advanced reactor systems, water-cooled SMRs require experimental data from both integral and separate thermal-hydraulics test facilities for the verification and validation (V&V) of the computational models and computer codes in order to design and obtain regulatory approval. The complex dynamics of two-phase flow-boiling instabilities includes flow regimes physics phenomena, flow-channel geometries, heat-transfer behavior, and interactions among the solid–liquid-gas within the system boundary, all of which are pivotal for understanding the design and operational challenges of SMRs. This study focuses on identifying the relevant knowledge gaps on boiling instabilities—specifically for a HCSG—and provides insights about future research direction optimizing the transport of thermal energy, mass-flow rates, and boundary conditions that ensure the adequate heat-transfer performance, operational stability, and safety associated with SMR systems
Supporting City Resilience Through Interoperable Platforms and Tools for Monitoring Natural Threats and Evaluating Their Impacts: A Case Study of Camerino
No full textNatural threats are becoming increasingly frequent and difficult to anticipate, urging public authorities and stakeholders to adopt sustainable methodologies and tools capable of continuously supplying historical and real-time data on hazards and their impacts. Such tools enable the prompt activation of recovery actions, enhance the resilience of citizens and the built environment, and contribute to the achievement of the Sustainable Development Goals (SDGs). This paper presents an interoperable and multipurpose framework developed within the MULTICLIMACT project (GA n. 101123538), designed to enhance urban smartness and sustainability, and to support and improve resilience in municipal decision-making. The framework integrates heterogeneous data sources into a unified environment, covering infrastructures, buildings, and social systems. It also includes physiological monitoring, which collects physiological parameters from wearable sensors in a privacy-preserving way, and microclimate monitoring, which records indoor air quality in inhabited environments. Simulation-based analyses are applied to capture cascading effects of disruptions, while multidimensional indicators (societal, economic, operational, and health-related) are used to quantify resilience. The approach was implemented in the Italian municipality of Camerino, where hazard monitoring systems, impact assessment tools, and indoor comfort data were integrated and validated in the SCP-MULTICLIMACT platform. The proposed approach offers a replicable model for integrating environmental and health data in support of climate resilience and sustainable urban development
Understanding Inter-Organizational Dynamics to Boost Circular Bioeconomy in the Bio-based Plastics Industry
No full textThis work examines existing inter-organizational configurations with the goal to identify and evaluate the key elements boosting Circular Bioeconomy (CBE) in the bio-based plastics industry. Indeed, while it is clear that multi-stakeholder engagement, together with cooperation, coordination and collaboration mechanisms, play a pivotal role in accelerating value creation and preservation for bio-based plastics, there is still the need to understand how these dynamics affect product development processes, end-user experiences and ultimately, the full circularity of the solutions proposed. Based on a conceptual framework, this study provides a structured lens to scrutinize the varying degrees of engagement and synergy among diverse entities operating in the bio-based plastics industry. Specifically, Alliances, Associations, Collaborative Research and Development, Consortia, Joint Ventures, Networks and Strategic Partnerships have been investigated. For each engagement mode, we delineate the scope, type and number of stakeholders involved, their specific roles, the motives addressed and funding involved, the operational timeframe, and the degree of innovation that resulted. Furthermore, the framework addresses factors that critically influence the strength of cooperation, coordination and collaboration mechanisms, such as trust, information, resources, and power. Drawing on real-world cases, we then present a non-exhaustive list of inter-organizational configurations already in place in the field of CBE. The work aims to help researchers, practitioners, and decision-makers to dissect and interpret the nature of inter-organizational dynamics among multiple stakeholders, in order to facilitate the understanding of the elements that drive successful synergies across organizational boundaries and boost a more effective CBE in the overall bio-based plastics industry
Sviluppo di processi di produzione ceramica. Additive manufacturing di zirconia stabilizzata con ittria attraverso la stampa DLP
Full text linkIl presente report descrive le attività svolte nell’ambito del progetto INSPIRATION (INtegrate and Sustainable PRocesses and mAterials for smarT ON demand laser additive manufacturing), finanziato dal PON “Ricerca e Innovazione” 2014–2020 e dal Fondo per lo Sviluppo e la Coesione (FSC). Il progetto ha avuto come obiettivo lo sviluppo di un sistema innovativo per la produzione on demand di polveri mediante tecnologia al plasma, destinate a processi di additive manufacturing. La validazione del sistema è stata condotta nel settore biomedicale, attraverso la realizzazione di manufatti ceramici e la messa a punto di ogni fase del processo, dalla materia prima al prodotto finito. Particolare attenzione è stata dedicata alla zirconia (ZrO2) che è stata selezionata come materiale di riferimento per la realizzazione di dimostratori biomedicali (viti e corone dentali), grazie alla sua elevata tenacità a frattura derivante dalla trasformazione di fase stress-indotta, che ne migliora la resistenza meccanica. La tecnologia di stampa additiva adottata è la Digital Light Processing (DLP), una tecnica stereolitografica basata su Vat Polymerization, che consente la costruzione layer-by-layer di componenti con elevata precisione dimensionale (spessore strato 20–50 μm) mediante fotopolimerizzazione controllata. Il progetto ha quindi dimostrato la fattibilità e l’efficacia del sistema integrato di produzione e stampa di materiali ceramici avanzati, evidenziando il potenziale della zirconia per applicazioni biomedicali ad alte prestazioni
Analysis and preliminary tests of optical system for calibration of photomultiplier neutron detectors of ITER Radial Neutron Camera
Full text linkLa Radial Neutron Camera (RNC) di ITER (International Thermonuclear Experimental Reactor), insieme alla Vertical Neutron Camera, ha come obiettivo quello di fornire, attraverso tecniche di ricostruzione applicate ai flussi di neutroni integrati, la misura risolta nel tempo del profilo del flusso neutronico generato durante il processo di produzione del plasma fusionistico. Più esattamente, con l’RNC si vuole valutare l’emissività neutronica, ovvero i neutroni emessi per unità di tempo e di volume. L’RNC è composto da due sottosistemi: l’RNC In-Port e l’RNC Ex-Port situati, rispettivamente, all’interno e all’esterno del Plug della Porta Equatoriale #01. In questo rapporto si presentano e discutono gli studi effettuati e i risultati ottenuti per la progettazione della ITER RNC focalizzandosi su un sistema ottico per la calibrazione di rivelatori neutronici a fotomoltiplicatore. Questi saranno infatti installati nella parte Ex-Port per la misura risolta nel tempo del flusso neutronico. Tali attività sono state effettuate nell’ambito di un accordo di collaborazione tra i laboratori ENEA NUC-TECFISDIM e NUC-FUSEN-DIA sul tema: “Sviluppo di una diagnostica ottica per ITER Radial Neutron Camera” che rientra nell’ambito delle attività di F4E (Fusione for Energy) assegnate ad ENEA (grant SG07).ITER’s (International Thermonuclear Experimental Reactor) Radial Neutron Camera (RNC), together with the Vertical Neutron Camera, aims to provide, through reconstruction techniques applied to integrated neutron fluxes, the time-resolved measurement of neutron flux profile generated during the fusion plasma production process. Specifically, neutron emissivity should be measured by the RNC, i.e. the neutrons emitted per unit time and volume. The RNC consists of two subsystems, the RNC In-Port and the RNC Ex-Port, located inside and outside the Equatorial Gate Plug #01, respectively. This report presents and discusses the studies performed and results obtained for the design of the ITER RNC focusing on an optical system for the calibration of photomultiplier neutron detectors. The latter will be installed in the Ex-Port part for time-resolved measurement of neutron flux. These activities were carried out within the framework of a collaboration agreement between the ENEA NUCTECFIS-DIM and NUC-FUSEN-DIA laboratories on the topic: “Sviluppo di una diagnostica ottica per ITER Radial Neutron Camera” (“Development of an optical diagnostics for ITER Radial Neutron Camera”) which is part of the F4E (Fusion for Energy) activities assigned to ENEA (grant SG07)
Due prospettive, un orizzonte: aspetti "Science" e "Citizen" del progetto Citizen Science CS4Rivers
Full text linkCitizen Science (CS) is a key tool and research approach to obtain the data required to address largescale research questions and engage the public in environmental issues. Since the use of CS data has quickly increased in recent years, concern has been expressed within the scientific community about the quality of these data. At the same time, public engagement raises other challenges and research questions. CS may generate collective benefits by providing opportunities for citizens to contribute to conservation actions and meaningfully engage in conservation policy. At the individual level, citizen scientists may gain awareness and a deeper understanding of environmental issues, increase their scientific literacy, and connect with their local environment. Equally, citizen scientists could face challenges and frustration, due to a lack of expertise and confidence in their skills. Therefore, scientific and citizen issues should be addressed to ensure the success and quality of a CS project. In this framework, the CS4Rivers project, led by the University of Siena, is a virtuous example of collaboration between local communities and scientists, working together to ensure valuable results. CS4Rivers is a CS project active in the Ombrone river basin (South Tuscany, Italy), with different participatory monitoring activities. Here, we present the simplified protocols and preliminary data quality assurance results concerning two sampling seasons of the macroinvertebrate community. We also present the testimonies provided by volunteers performing the sampling to highlight their feelings and better understand the “Science” and “Citizen” aspects of a Citizen Science project
The TOP-IMPLART high-energy protron beam delivery line: a comparison of SRIM, FLUKA, and Fermi-Eyges theory predicions
Full text linkNell'ambito del progetto TOP-IMPLART, è stata progettata ed è in fase di “commissioning” una linea di rilascio del fascio per l'acceleratore lineare di protoni TOP-IMPLART dedicata a irraggiamenti a scansione di bersagli estesi a energie di 63 e 71 MeV. Per pianificare adeguatamente tali irraggiamenti, è necessario conoscere la dimensione laterale e la dispersione angolare del fascio che arriva sul piano del bersaglio. In una fase preliminare questa valutazione può essere eseguita utilizzando simulazioni e modelli teorici. In questo Rapporto Tecnico, esaminiamo il progetto attuale della linea di trasporto del fascio TOP-IMPLART utilizzando due codici Monte Carlo, SRIM e FLUKA, nonché un approccio numerico basato sulla teoria di Fermi-Eyges. I risultati mostrano che SRIM sottostima la dimensione laterale e la dispersione angolare del fascio sul piano del bersaglio rispetto a FLUKA. Un test sperimentale conferma che SRIM sottostima la dimensione del fascio, mentre FLUKA è in buon accordo con l'esperimento. Le previsioni della teoria di Fermi-Eyges sono più vicine ai risultati forniti da FLUKA.In the framework of the TOP-IMPLART project, a beam delivery line has been designed and is under commissioning for the TOP-IMPLART proton linear accelerator to enable irradiation scans of extended targets at energies of 63 and 71 MeV. To suitably plan these irradiations, it is necessary to know the lateral size and angular spread of the beam arriving at the target plane. In a preliminary stage, this evaluation can be performed using simulations and theoretical models. In this Technical Report, we examine the current design of the TOP-IMPLART beam delivery line using two Monte Carlo codes, SRIM and FLUKA, as well as a numerical approach based on the Fermi-Eyges theory. The results show that SRIM underestimates the beam’s lateral size and angular spread of the beam at the target plane compared to FLUKA. An experimental test confirms that SRIM underestimates the spot size, while FLUKA is in good agreement with the experiment. The predictions of the Fermi-Eyges theory are closer to the results provided by FLUKA
Geometric approach based tool for shallow landslides propagation assessment (ShaLPA) at basin scale
No full textHazard maps for shallow landslides at the basin or regional scale often provide information solely about past events and/or potential source areas. Despite the availability of several propagation assessment software tools, runout maps for potential shallow landslides at the basin scale remain scarce. To address this gap, the ShaLPA runout GIS tool was developed as an easy-to-use and efficient solution. Based on a geometric approach, the tool consists of five distinct, sequential scripts that begin with defined source areas. By processing a detailed Digital Terrain Model, the first script identifies the starting points and the second traces the potential paths of shallow landslides. The third script calculates the runout, while the fourth estimates velocity distribution and kinetic energy along the paths. The fifth script assess the reliability of the model results using two different indicators. ShaLPA was first tested in the Giampilieri and Briga area (Sicily, Italy), providing encouraging results. The simplicity of the ShaLPA tool promotes the integration of runout and failure susceptibility analyses, enhancing the comprehensiveness of hazard and risk assessment and improving the effectiveness of landslide mitigation measures