Browsing by Author "Critelli, Salvatore"

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Analysis of fracture phenomena in concrete structures by means of cohesive modeling techniques
(Università della Calabria, 2021-06-30) De Maio, Umberto; Critelli, Salvatore; Greco, Fabrizio; Nevone Blasi, Paolo
Still today, the fracture phenomenon in cementitious materi-als is a research topic widely investigated by numerous research-ers in materials and structural engineering, since it involves many theoretical and practical aspects concerning both strength and durability properties of common concrete structures. In-deed, cracking is one of the main causes of the severe deteriora-tion of concrete structures, usually leading to an unacceptable re-duction of their serviceability time. The fracture processes, in-cluding onset, propagation, and coalescence of multiple cracks, arise in the structural members because of the low tensile strength of concrete, which is ultimately related to the existence of voids or undetected defects in the material microstructure.Such cracking processes significantly affect the global mechani-cal behavior of the concrete structures and may facilitate the in-gress of corrosive media; therefore, in the scientific community there is a strong interest in reducing cracks width to a minimum or in preventing cracking altogether. In the technical literature, several simplified numerical models, based on either linear-elas-tic or elastic-plastic fracture mechanics, are proposed to predict the fracture mechanisms during any stage of the lifetime of con-crete structures. However, the application of these models is somehow limited, due to their incapacity to capture the complex inelastic mechanical behavior of reinforced concrete members, involving multiple concrete cracking and steel yielding and their mutual interaction under the combined action of axial and bend-ing loadings. This thesis aims to develop a sophisticated numerical frac-ture model to predict the cracking processes in quasi-brittle ma-terials like concrete, and the main failure mechanisms of the re-inforced concrete structures in a comprehensive manner. The proposed methodology relies on a diffuse interface model (DIM), based on an inter-element cohesive fracture approach, where co-hesive elements are inserted along all the internal mesh bounda-ries to simulate multiple cracks initiation, propagation and coa-lescence in concrete. Such a model, is used in combination with an embedded truss model (ETM) for steel reinforcing bars in the failure analysis of reinforced concrete structures. In particular, truss elements equipped with an elastoplastic constitutive be-havior are suitably connected to the concrete mesh via a bond-slip interface, in order to capture the interaction with the sur-rounding concrete layers as well as with the neighboring propa-gating cracks. The proposed fracture model takes advantage of a novel mi-cromechanics-based calibration technique, developed and pro-posed in this thesis, to control and/or reduce the well-known mesh dependency issues of the diffuse cohesive approach, re-lated to the artificial compliance in the elastic regime. In this way, the initial stiffness parameters of the cohesive element employed in the diffuse interface model are suitably calibrated by means of a rigorous micromechanical approach, based on the concept of representative volume element. In particular, by performing sev-eral micromechanical analyses two charts have been constructed which provide the dimensionless normal and tangential stiffness parameters as functions of both the Poisson’s ratio of the bulk and the admitted reduction in the overall Young’s modulus after the insertion of the cohesive interfaces. The proposed fracture model has been firstly validated by performing numerical analysis in plain concrete elements, and secondly, employed to analyze the failure mechanisms in exter-nally strengthened reinforced concrete beams. In particular, several numerical simulations, involving pre-notched concrete beams subjected to mode-I loading conditions, have been performed to investigate the capability of the diffuse interface model to predict self-similar crack propagation and to assess the mesh-induced artificial toughening effects, also intro-ducing two new fracture models for comparison purpose. More-over, sensitivity analyses with respect to the mesh size and the mesh orientation have been performed to investigate the mesh dependency properties of the proposed fracture model. Further validation of the proposed diffuse interface model has been pro-vided for plain concrete structures subjected to general mixed-mode loading conditions. The role of the mode-II inelastic parameters (i.e. critical tangential stress and mode-II fracture en-ergy) on the nonlinear behavior of the embedded cohesive inter-faces is investigated in a deeper manner. In particular, two sen-sitivity analyses have been performed by independently varying the mode-II inelastic parameters required by the traction-separa-tion law adopted in the proposed concrete fracture model, in or-der to quantify the above-mentioned artificial toughening effects associated with mode-II crack propagation. Moreover, compari-sons with numerical and experimental results, with reference to mode-I and mixed-mode fracture tests, have been reported, highlighting the effectiveness of the adopted diffuse interface model (DIM) in predicting the failure response in a reliable man-ner. Subsequently, the integrated fracture approach is success-fully employed to predict the nonlinear response of (eventually strengthened) reinforced concrete beams subjected to general loading conditions. Firstly, the failure analysis of reinforced con-crete (RC) beams has been performed to assess the capability of the integrated fracture model to capture multiple crack initiation and propagation. Detailed stress analysis of the tensile reinforce-ment bars has been also reported to verify the capability of the embedded truss model (ETM) of capturing the tension stiffening effect. Secondly, the well-known concrete cover separation phe-nomenon has been predicted by performing complete failure simulations of FRP-strengthened RC elements. To this end, a sin-gle interface model (SIM) has been incorporated in the proposed fracture model to capture the mechanical interaction between the concrete element and the externally bonded reinforced system and to predict eventually debonding phenomena in con-crete/FRP plate interface. Suitable comparisons with available experimental results have clearly shown the reliability and the effectiveness (in terms of numerical accuracy) of the adopted fracture approach, especially in the crack pattern prediction. Fi-nally, the proposed integrated numerical model is used to pre-dict the structural response of ultra high-performance fiber-rein-forced concrete (UHPFRC) structures enhanced with embedded nanomaterials. In this case, the cohesive elements are equipped with a mixed-mode traction-separation law suitably calibrated to account for the toughening effect of the nano-reinforcement. The main numerical outcomes, presented in terms of both global structural response and final crack pattern, show the ability of the proposed approach to predict the load-carrying capacity of such structures, as well as to highlight the role of the embedded nano-reinforcement in the crack width control.
Applicazione dei big data nel turismo, marketing ed education
(Università della Calabria, 2020-03-18) Giglio, Simona; Critelli, Salvatore; Pantano, Pietro
Il mondo è attualmente inondato da dati e l’avanzare delle tecnologie digitali amplifica questo fenomeno in modo esponenziale. Tale fenomeno viene etichettato con il concetto di Big Data ovvero le tracce digitali che le nostre attività quotidiane lasciano per effetto dell’uso massiccio dei sistemi ICT (Information Communication Technologies). I Big Data sono diventati il nuovo microscopio che rende “misurabile” la società. Per tali ragioni, la ricerca è incentrata sull’analisi dei Big data, estratti dai social media, da indagini online, da piattaforme di recensioni e da database, attraverso l’applicazione di tecniche e strumenti sviluppati nell’ambito dell’Intelligenza Artificiale. Algoritmi di machine learning, analisi semantica ed analisi statistica sono stati utilizzati per estrarre, dai Big Data, informazione sotto forma di “conoscenza” e “valore”, dimostrando come dati di grandi dimensioni possano fungere da ricca fonte di informazione, da un lato, per comprendere il comportamento dell’utente, parte integrante di una società complessa (conoscenza), e dall’altro, per sostenere i processi decisionali e i servizi forniti agli utenti/consumatori (valore). Il lavoro si caratterizza per un approccio multidisciplinare tra settori differenti quali le scienze sociali, le scienze statistiche e l’informatica. Questo ha permesso di fondare la ricerca sui Big Data nella teoria, e fornire un efficace recupero e analisi dei dati nella pratica. Le tecniche di machine learning sono state applicate per (i) il riconoscimento delle immagini, (ii) per la creazione di cluster, (iii) per l’analisi del testo (sentiment analysis) e (iv) per la profilazione di classi di utenti. Per il riconoscimento delle immagini l’approccio ha richiamato le reti neurali artificiali (deep artificial neural networks), algoritmi e sistemi computazionali ispirati al cervello umano utilizzando le potenzialità del programma Wolfram Mathematica e la disponibilità di dati estratti da social network quali Flickr, Twitter, Instagram ed altre piattaforme come TripAdvisor. Gli strumenti utilizzati nella ricerca hanno permesso di indagare e di rilevare in modo oggettivo dall’analisi di immagini e di testi condivisi sul web, alcuni comportamenti cognitivi degli utenti/consumatori alla base delle loro scelte nonché l’attrattività di una destinazione turistica e la qualità dell’esperienza dell’utente. Lo studio del significato delle parole nel testo ha aperto la strada al web semantico che permette ad un utente di acquisire informazioni approfondite durante una ricerca attraverso un sistema formato da una rete di relazioni e connessioni tra documenti. Partendo dalle ricerche di Ogden e Richards sullo studio del significato e di Jakobson che studiò i processi comunicativi, si è cercato di strutturare e sistematizzare un processo che riflette un atto comunicativo ed informativo tale che un simbolo (immagine) attraverso l’applicazione di un significante (machine learning che si sostituisce al processo mentale proprio dell’uomo) permettesse l’esplicitazione di un referente (oggetto\etichetta) che opportunatamente porta alla trasmissione di un messaggio sotto forma di conoscenza. Il tutto coordinato da un sistema in grado di coniugare fattori differenti in un’ottica interdisciplinare dove l’analisi dei dati combacia perfettamente con la linguistica. Attingendo da studi precedenti, i risultati raggiunti dimostrano che gli algoritmi di analisi dei Big Data quali l’apprendimento automatico contribuiscono da un lato alla comprensione sull’esperienza dell’utente verso un luogo, una destinazione; d’altra parte, la loro analisi fornisce una conoscenza sistematica delle valutazioni dei consumatori su un determinato prodotto o servizio e verso lo sviluppo di una sorta di “intelligenza sociale”. Inoltre i risultati della ricerca propongono come, un approccio più sofisticato al monitoraggio dei social media nel contesto turistico e nel marketing, nonché nel settore dell’education, possa contribuire a migliorare le decisioni strategiche e le politiche operative degli stakeholder nonché ad avere una visione psicologica sugli atteggiamenti e sul comportamento di un ampio spettro di utenti.
Applicazione della shallow water equations per la simulazione numerica a scala di bacino degli eventi alluvionali
(Università della Calabria, 2020-04-16) Gangi, Fabiola; Critelli, Salvatore; Macchione, Francesco; Costanzo, Carmelina
La valutazione del rischio idraulico connesso alle piene dei corsi d’acqua è particolarmente delicata quando gli eventi alluvionali hanno carattere impulsivo, come accade nei bacini di modeste dimensioni. L’approccio correntemente utilizzato per l’analisi idraulica è quello di individuare dei singoli tratti di interesse dei corsi d’acqua. L’analisi è condotta sulla base di idrogrammi di progetto ricavati mediante modelli idrologici del tipo afflussi-deflussi. In questa memoria sarà invece applicato un approccio basato sull’analisi degli effetti idraulici provocati da un evento meteorico considerando come dominio per il calcolo idraulico l’intero bacino idrografico. Tale approccio è in grado di individuare situazioni di pericolo in zone che magari non sarebbero state esaminate. L’uso di modelli idrodinamici basati sulle shallow water equations, è diventato oggetto di crescente interesse per simulare eventi a scala di bacino. Un fattore che può essere limitante ai fini dell’ottenimento di risultati conseguibili con il dettaglio fisico garantito dalle SWEs è la dimensione delle celle di calcolo. Questa deve essere sufficientemente piccola da garantire un’accurata simulazione degli effetti idraulici e contestualmente non troppo piccola per non rendere proibitiva la mole dei calcoli su domini estesi. In questa ottica, il presente lavoro propone di occuparsi dell’individuazione dei criteri per la delimitazione delle aree a pericolosità idraulica definendo la più grande dimensione che può essere assegnata alla cella di calcolo per ottenere risultati sufficientemente affidabili. A tal fine, un modello numerico basato sulle SWE, sviluppato dagli autori e parallelizzato utilizzando le direttive OPENMP e MPI, è stato applicato al bacino del fiume Beltrame, collocato sulla costa Est della Calabria. Il torrente Beltrame, come altri torrenti della fascia ionica calabrese, è stato interessato, in passato, da eventi alluvionali di notevoli dimensioni. Si prenderà qui in esame l’evento accaduto il 10 settembre 2000. La risoluzione dei dati topografici a disposizione è variabile. Il 39% ha una copertura di dati DTM a risoluzione 5 metri, il 59% ha copertura di dati LiDAR a risoluzione 1 metro e l’2% ha copertura di dati LiDAR a risoluzione 2 metri. A partire dai dati topografici, sono stati generati quattro domini computazionali con griglie di tipo non strutturato, uniforme, con elementi triangolari (con area variabile da 36 a 900 m2). Le differenze tra i risultati ottenuti sono stati confrontati in termini di estensione di aree allagate e distribuzione dei valori della pericolosità all’interno delle aree perimetrate, quest’ultima quantificata secondo il prodotto hV, dove h è la profondità della corrente in un assegnato punto e in un assegnato istante e V è la contestuale velocità. La valutazione della sovrapponibilità delle aree per ciascuna classe di pericolosità è stata eseguita utilizzando diversi indici quali: Hit Rate, False Alarm Ratio, Critical Success Index. L’analisi condotta nella presente memoria ha messo in luce che, a scala di bacino, gli errori sui massimi tiranti crescano significativamente al crescere delle dimensioni delle celle di calcolo, sebbene essi si mantengano più contenuti, anche usando le griglie più grossolane, per la parte valliva, caratterizzata da estensioni più ampie dell’area allagata. In ogni caso sembra che questo abbia una scarsa ricaduta sulla valutazione della pericolosità. I calcoli e i confronti hanno mostrato che le aree a diversa pericolosità si distribuiscono all’interno dell’area del bacino in maniera simile. Inoltre, anche se non si arriva ad una perfetta sovrapposizione areale, esse sono collocate spazialmente in modo che o si sovrappongono parzialmente o, se sono delle strisce sottili, hanno dislocazioni molto prossime le une alle altre. si ritiene che anche con la griglia più grossolana si possa impiantare una buona analisi della pericolosità a scala di bacino, certamente con precisione maggiore andando dai rami montani del reticolo – più stretti - a quelli più ampli che provocano esondazioni in zone vallive.
Approccio metodologico per la valutazione modulare della vulnerabilità finalizzata alla riduzione dei rischi naturali antropici 2021
(Università della Calabria, 2021-05-10) Maletta, Roberta; Critelli, Salvatore; Mendicino, Giuseppe
Vulnerability is an important component of risk assessment and represents the main element in the risk perception. Typically, the characteristics related to social, cultural, physical and institutional factors increase the susceptibility of an individual or a community, to the impacts of hazards. Vulnerability is described as a dynamic phenomenon that can vary significantly across time and space; it is greatly influenced by human actions and behaviors, by the emergency response related to road accessibility. As a consequence, there is a continuing need for risk reduction disaster strategies to shift attention from assessing hazard events toward reducing vulnerabilities within social systems. Describing and quantifying vulnerability is an important challenge along this path. Our current understanding of vulnerability is guided by methodologies, indicators and measurement standards derived from different schools of thought. This thesis presents a methodological approach to describe and to assess the vulnerability index at the inter-municipal scale, using three indices. Spatial analysis is conducted on the basis of census zones in an area defined as “Territorial Context” (TC) characterized by the union of municipalities. A measure of modular vulnerability is evaluated on the basis of inductive methods. Vulnerability is defined as the conditions determined from social and economic factors from human and climatic territorial pressures, from critical issues generated by past events and from the functioning of road infrastructures during an event. The three modular components of the vulnerability are: TCVIpeople (Territorial Context Vulnerability index-people); TCVIexposure (Territorial Context Vulnerability index-exposure); and TCVIemergency (Territorial Context Vulnerability index-emergency). Thirty-eight variables are selected and geoprocessed for each of the 195 census analysis units in the Mediterranean study area of southern Italy. Using Principal Components Analysis (PCA) with varimax rotation and Kaiser criterion for component selection, the social and territorial vulnerability index, are identified. The third vulnerability index, TCVIemergency, is processed through the transport modeling technique. In the latter case, a contextual interruption of all road network exposed to the highest level of hazard is assumed. Models are implemented to assess the forest fire, flood and landslide hazards. The TCVIemergency index is calculated (on the basis of the differences in travel time, after and before the event, from the origin (centroids of the census areas) to the destination points (strategic buildings in emergency planning and civil protection operational structures), using the shortest paths network model. This index can provides useful information for evacuation planning and rescue operation during emergency situations. A fuzzy logic model is used to evaluate the vulnerability classification, while the fuzzy overlay function is used to calculate the final aggregate TCVI index. The performance of classification models is measured by some statistical metrics. A dedicated Geographic Information System (GIS) is used to capture, geo-process and display spatial data recorded at different scales. The GIS technology allows to evaluate and visualize the results, through maps, as a realistic representation and to identify and manage the process. The results contribute to debates in contemporary literature on vulnerability in many ways. First these analyses constitute an attempt to quantify and mapping vulnerability at census area in a natural or handmade scenario. Secondly new variables like the road network representing the category most damaged during the events, with the greatest repercussions on the community and on the economy, are introduced. The current methods of vulnerability assessment are in fact mainly based on social aspects, the built environment and climatic factors, leaving out the importance of the road infrastructure. The model is developed at the census area, which is the smallest geographic unit that the National Institute of Statistics uses to aggregate demographic data, in an inter-municipal area. It is well known that vulnerability is a scale-dependent variable and it could be very accurate for larger spatial scales than the TC area. Moreover, new classification criteria for vulnerability maps are investigated, using fuzzy set theories. Finally, working with the territorial contexts TC, a new approach for risk reduction is defined, in order to better meet the needs of the Civil protection activities. This is the first national attempt to calculate the spatial distribution of vulnerability in a territorial context functional to emergency planning. Through this study, a comprehensive understanding of the relative driving components contributing to the overall vulnerability is achieved. Results show significant differences in the spatial distribution of the social vulnerability, highlighting the multidimensionality and heterogeneity of the municipal characteristics. The TCVI in the southern and central part of TC is higher than that its northern and western parts. In general, by analyzing the results of the vulnerability values it must be noted that about 56% of census areas are characterized by low and low-medium, while 35 % fall into categories labelled with high, very high and the remaining 9% falls into the moderate vulnerability category. The vulnerability maps provide useful territorial information, that can support policy-makers for prevention and emergency management. Within the context of natural and handmade hazards, the TCVI could be used to manage the repartition of resource, helps to determine which places may need specialized attention during immediate response and long-term recovery after an extreme event. It can provide an indication of the housing areas that need development and humanitarian aids and can provide guidance for better preparedness, response and mitigation strategies. The vulnerability maps can also be used as guidance to road administrations in the planning and in their investment to prioritize interventions and for normal maintenance and control activities. Actions and emergency measure are directly connected with resilience, then this work can help to strong intent to increase capacity building of human resources, better land use management, increasing preparedness and emergency measures that are taken during and after event. Following the introduction section, the present study is composed by two main sections that delve into: 1) conceptual frameworks for vulnerability and hazards assessments. This is accomplished by discussing the relevant primary research literature and analyzing the events recorded in the past; 2) methodological approaches to model natural and anthropic hazards and for vulnerability measuring in a Territorial Context. An application in the Territorial Context of Marina of Gioiosa Ionica in Southern Italy, is developed. Finally, the last section presents the main conclusions of the study and potential developments. Keywords: forest fire, landslide and flood hazard, vulnerability index, territorial context, indices and maps, social and territorial vulnerability, road susceptibility.
Compositional and textural study of beach sands from active volcanic areas (southern tyrrhenian sea)
(2018-05-11) Morrone, Consuele; Critelli, Salvatore; De Rose, Rosanna; Le Pera, Emilia; Marsaglia, Kathleen M.
The main goal of this research focuses on the provenance, compositional and textural investigation of modern sand supplied from volcanic terrains (southern Tyrrhenian sea). This is a contribution to quantify the controls on volcaniclastic sand composition among volcanic areas with different tectonic settings and compositions. Specifically, an important aim of this research is to quantitatively compare the relation between areal distribution, texture and composition of “source” lithotypes – which are the clastic debris producer – with respect to texture and composition of "volcano-derived" sediments. The study area covers the coastal perimeter/stretch of two Italian volcanic provinces in the southern Tyrrhenian sea: Aeolian islands and Campania province. Particular attention has been given to the factors that control the relationships between grain rounding, grain-size, sand composition, texture and source rocks. This research provide a good opportunity to define the provenance signatures of detritus eroded from lavas with different compositions, pyroclastic and minor sedimentary rocks. Different sandy petrofacies for the studied areas of Campania province have been formalized. In order to investigate on provenance, pre-burial processes, composition and texture of modern sand supplied from volcanic terrains, different studies have been carried out through:  Sieving analyses;  Polarizing microscope and Electron Microprobe;  Image analysis (roundness study);  Geographic Information System analysis (SGI calculation). There is a clear differences between Aeolian Islands costal beach sand and Campania coastal beach sand in terms of detritus maturity. Grain-size distribution within Aeolian beach sediment show a tendency towards coarser sand fraction to gravel, whereas Campania coastal samples show a tendency towards medium to fine sand fractions; this indicates a varied physical disintegration of the source rocks. The major components of Aeolian islands and Campania beach sands are monomineralic grains, sedimentary and volcanic lithic fragments with lesser amounts of calcareous bioclasts. Samples from Aeolian islands and Portici Sorrento coastal stretch have an high percentage of volcanic lithic fragments (Lvl > Lvmi> Lvv), whereas samples from Pozzuoli, display an average percentage among Lvl~Lvmi~Lvv. Three different petrofacies have been defined along Campania coastal stretch: sedimentary (Apennines), Vesuvian and Phlegrean fields petrofacies. Stromboli, Vulcano, Alicudi and Filicudi sands have a dual basaltic/shoshonitic and andesitic composition “signatures”. Panarea, Lipari and Salina sands have a wider range of composition “signatures” ranging from basalts to rhyolites. there is evidence that, on Aeolian islands, sand composition does accurately reflect bedrock composition except in the case of source areas dominated by pumice outcrops (e.g. Lipari islands), whereas in more protected and quite beach-environment such as Pozzuoli bay, this grain types (pumice, associated to more evolved [acid] volcanism and then explosive volcanism) have been found and resulted to be texturally more preserved. In the sandy detritus the persistence for the lithic grains is ranked as follows: Lvlblg, Lvmiblgl, Lvvblgl > Lvlbrgl, Lvmibrlgl, Lvvbrgl > Lvlclgl, Lvmiclgl, Lvvclgl > Lvf > Lvlgrgl, Lvmigrgl, Lvvgrgl, pumice. Thus, mafic source rocks will be overestimated and more acid source rocks will be underestimated in the stratigraphic record. New volcanic lithic compounds have been introduced (Lvlgrgl, Lvmigrgl, Lvvgrgl) then who will study the ancient stratigraphic records will know that the Lvlgrgl means dacitic provenance. New discriminating diagrams have been introduced which allow to obtain important information among the volcanic source rocks ranging from basic to acid composition. Lvlblgl, Lvmiblgl, Lvvblgl (1); Lvlbrgl, Lvmibrgl, Lvvbrgl (2); Lvlgrgl, Lvmigrgl, Lvvgrgl (3) can be produced not only by basaltic, andesitic and dacitic source rocks but also by source rocks with the same SiO2 content belonging at different alkaline series (e.g. trachybasalt, shoshonite, latite, trachyandesite, trachydacite, trachyte). Campania samples displaying an higher roundness degree which decrease towards Phlegrean Fields area from north (Volturno river mouth) to south and, show an higher percentage of (3), (4), (5) and (6) roundness category, whereas Aeolian islands samples have an higher percentage of (1) and (2) roundness category. There is a correlation between roundness and geographic location of the Aeolian islands beaches. Sand grains round more efficiently under gentler wave action of the eastern side whereas the more angular grains of the north-western beaches are immediately eroded from the nearby cliffs with null or quite minimal reworking. A new methodological and research approach for roundness degree calculation have been tested by conducting image analysis. By relating GIS, compositional and textural results, it is possible to affirm that lavas source rocks have an higher propensity to create sandy detritus than pyroclastic source rocks. This finding has implications for the stratigraphic record especially for the sandy pumice clasts which could be underrepresented in older volcaniclastic deposits and overrepresented in other detritus size fractions. This actualistic study helps in understanding factors controlling siliciclastic sediment composition and texture, in turn, will help in deciphering major controls on ancient volcaniclastic successions, especially those where volcanic terrains have been totally lost by erosion
Construction and test of high resolution and radiation hard particle detectors for fundamental physics at the LHC experiments and search for signal of new physics through displaced and collimated jet-like structures with ATLAS experiment
(Università della Calabria, 2021-11-08) Carducci, Giovandomenico; Critelli, Salvatore; Schioppa, Marco
Control system for a nanogrid for home application: dynamic analysis and and implementation aspects using a behaviour tree
(2018-06-01) Motta, Michele; Critelli, Salvatore; Menniti, Daniele; Pinnarelli, Anna; Sorrentino, Nicola
Crack propagation modelling in layered structures by using moving mesh method
(2019-05-10) Funari, Marco Francesco; Critelli, Salvatore; Leonetti, Paolo
The study presented in this PhD thesis is focused on development of advanced numerical models to describe crack propagation and interface decohesion phenomena in laminate and sandwich structures. The general idea is to simulate crack tip motion by using a moving mesh methodology to reproduce quasi-static and fast crack propagation phenomena in layered structures. Without going into too much details, the nodes are moved to predict changes of the geometry produced by the crack motion allowing to avoid several remeshing and saving computational time. The thesis presents a series of numerical investigations, which are performed in order to validate the introduced features in the numerical methodology along the development process. The starting point of the research was the investigation of the interface crack propagation phenomena in multilayered structures simulated by using shear deformable beam elements. The theoretical formulation was based on Arbitrary Lagrangian and Eulerian (ALE) methodology and cohesive interface elements, in which weak based moving connections are implemented by using a finite element formulation. In this framework, only the nodes of the computational mesh of the interface region are moved on the basis of the predicted fracture variables, reducing mesh distortions by using continuous rezoning procedures. The use of moving mesh methodology in the proposed model allow us to introduce nonlinear interface elements in a small region containing the process zone, reducing the numerical complexities and efforts, typically involved in standard cohesive approach. Furthermore, this numerical methodology was developed to investigate the strategy commonly adopted to improve the interlaminar strength of composite laminate. Basically, in order to simulate the z-pins reinforced area, a set of discrete nonlinear springs fixed to material domain was introduced. As is well known, a very important feature that should have a numerical model is the capability to simulate both crack onset condition and coalescence phenomena in structures with initial perfect interfaces. To this end, proper script files were carried out to manage the steps involved in the procedure, regarding the geometry variation due to the crack onset, the debonding length definition and the mesh enrichment in the process zone. The numerical strategy could be solved in both static and dynamic frameworks, taking into account time dependent effects produced by the inertial characteristics of the structure and the boundary motion involved by debonding phenomena. In both cases, the governing equations have been integrated by means of proper stop and restart conditions, to modify the computational mesh due to the onset of debonding phenomena. The ability of the proposed model has been verified by simulating several onset configurations, including the case, in which multiple debonding mechanisms with coalescence affect the interfaces. The research project has been focused on the study of the sandwich structure failure modes. From physical and mathematical viewpoints, two main issues are demanding a detailed understanding of the mechanical behaviour of sandwich panels: the propagation of internal macro-cracks in the core and the delamination at skin/core interfaces. To concern the delamination between skin and core, previous numerical strategy, already used in the framework of composite laminate, was generalized simply by modifying the relative displacement between skin (shear deformable beam) and core (2D plane stress formulation). In order to simulate the macro crack propagation in the core, the ALE approach has been generalized in two-dimensional framework. The approach has combined concepts arising from structural mechanics and moving mesh methodology, which was implemented in a unified framework to predict crack growth on the basis of Fracture Mechanics variables. In particular, moving computational nodes were modified starting from a fixed referential coordinate system on the basis of a crack growth criterion to predict directionality and displacement of the tip front. The use of rezoning mesh methods coupled with a proper advancing crack growth scheme has ensured the consistency of mesh motion with small distortions and an unaltered mesh typology. In addition, the moving grid was modified from the initial configuration in such a way that the recourse to remeshing procedures has been strongly reduced. Numerical formulation and its computational implementation have shown how the proposed approach can be easily embedded in classical finite element software. Numerical examples in presence of internal material discontinuities and comparisons with existing data obtained by advanced numerical approaches and experimental data have been proposed to check the validity of the formulation. Furthermore, the crack propagation in the core of sandwich structures has been analysed on the basis of fracture parameters experimentally determined on commercially available foams. The (summary) thesis comprises the following: Chapter 1 - Introduction (thesis topics, literature review, aims and scope); Chapter 2 and 3 - present theoretical formulation and numerical implementation followed by results of the numerical methodology to describe crack onset, propagation and coalescence respectively; Chapters 4 - reports the numerical investigation about sandwich structure failure modes and the generalization of the ALE approach to simulate crack propagation in 2D continuum (core); Chapters 5 -presents the conclusions and future works
Decoration and Characterization of Carbon-based nanomaterial for third generation photovoltaic devices
(2018-03-16) Imbrogno, Alessandra; Critelli, Salvatore; Bonanno, Assunta; Macario, Anastasia; El Khakani, Alì
The PhD project is oriented on the synthesis and characterization of carbonbased nanomaterial and their eventual decoration with pulsed laser deposition technique for the developing of advanced nanomaterial suitable for photovoltaic application, in particular in DSSC devices. The dye sensitized solar cells belong to the third generation of photovoltaic devices, and are mainly composed of two electrodes deposited on FTO conductive glasses: the photoanode is also called \working electrode" (WE) and it is made of a thin lm of TiO2 deposited on a conductive FTO glass and sensitized by an organic dye, while the cathode, called \counter electrode" (CE), is made of a thin lm of platinum sputtered on a conductive FTO glass. The space between these two electrodes is lled with an electrolyte solution composed of a redox couple. The great advantage of these solar devices respect to traditional silicon-based solar devices is the relatively easy fabrication processes and the use of materials that are abundant on Earth. However, their conversion e ciency is still unsatisfactory, with conversion e ciency that barely reach the 18% for the solid-type DSSC and the 10% for the liquid-type of DSSC. The main issues that a ect the photovoltaic e ciency in DSSC are the dye deterioration, the high e-/h+ recombination in TiO2-dye substrate, the contact resistance between CE and electrolyte, and the degradation of the platinum counter electrode due to the electrolyte solution. During the last two decades many e orts have been made to resolve these issues, and some advances have been made by modify both the working and the counter electrodes. This Ph.D. project is focused on improving the materials used in both electrodes in liquid-type DSSC by using carbon nanomaterials. In particular, for what concern the counter electrode, the expensive platinum was substituted with multi walled carbon-nanotubes (MWCNT) decorated with metal nanoparticles that ensured both a good resistance to the corrosive action of the electrolyte solution and a highly rough surface that improved the catalysis of the redox reaction, resulting in a improvement of the photovoltaic performance of the DSSC device. For what concern the working electrode, instead, this Ph.D project was focused on the insertion of di erent carbon-based nanomaterials as multiwalled carbon nanotubes and graphene inside the TiO2 thin lm to reduce the loss of electron due to the e-/h+ recombination. Even in this case, the results showed interesting improvements of the photovoltaic e ciency of the DSSC device. All the experiments were conducted in both University of Calabria (Italy) and Institut National de la Recherche Scienti que (Canada).
Development of advanced systems for energy conversion based on innovative two- dimensional materials
(Università della Calabria, 2021-09-27) Zappia, Isabella; Critelli, Salvatore; Chiarello, Gennaro; Cupolillo, Anna
The even growing energy demand due to the demographic growth and the consequent economic expansion has led to the search for innovative technologies available for energy production and conversion from green and renewable sources such as solar energy. In this context, twodimensional (2D) materials, including either single- and few-layer flake forms, are constantly attracting more and more interest as potential advanced photo(electro)catalysts for redox reactions leading to green fuel production. Recently, layered semiconductors of group-III and group-IV, which can be exfoliated in their 2D form due to low cleavage energy (typically < 0.5 J m-2), have been theoretically predicted as water splitting photocatalysts for hydrogen production. For example, their large surface-to-volume ratio intrinsically guarantees that the charge carriers are directly photogenerated at the interface with the electrolyte, where redox reactions take place before they recombine. Moreover, their electronic structure can be tuned by controlling the number of layers, fulfilling the fundamental requirements for water splitting photocatalysts, i.e.: 1) conduction band minimum (CBM) energy (ECBM) > reduction potential of H+/H2 (E(H+/H2)); 2) valence band maximum (VBM) energy (EVBM) < reduction potential of O2/H2O (E(O2/H2O)). A requirement for large-scale applications is the development of low-cost, reliable industrial production processes. In this scenario, liquid-phase exfoliation (LPE) methods provide scalable production of 2D materials in form of liquid dispersions, enabling their processing in thin-film through low‐cost and industrially relevant deposition techniques. This thesis investigates, for the first time, the photoelectrochemical (PEC) activity of single-/fewlayer flakes of GaS, GaSe, and GeSe produced through ultrasound-assisted LPE in environmentally friendly solvents (e.g., 2-propanol) in aqueous media. Our results are consequently used to design proof-of-concept PEC water splitting photoelectrodes, as well as PEC-type photodetectors. Moreover, structural and electronic properties of PtTe2 have been investigated, being this material a potential catalyst for the hydrogen evolution reaction (HER) and other fuel-producing electrochemical reactions.
Drinking water supply modelling for advanced metering Infrastructures
(Università della Calabria, 2021-09-27) Bonora, Marco Amos; Critelli, Salvatore; Maiolo, Mario; De Oliveira Sousa, Joaquim Josè; ;
L’evoluzione della società umana e dei processi produttivi sta accrescendo il fabbisogno idrico mondiale. La risorsa idrica è distribuita in maniera disomogenea e sta subendo una progressiva riduzione a causa dei cambiamenti climatici in atto. La necessità di gestire con maggiore attenzione e di ottimizzare il Sistema idrico integrato rende necessario l’utilizzo di strumenti messi a disposizione da nuove tecnologie che devono collaborare in una gestione multidisciplinare ed integrata. Le attuali normative italiane ed europee sanciscono tale necessità, prescrivendo l’utilizzo di strumenti elettronici specifici per la progettazione e la creazione di database territoriali standardizzati e di facile accesso. L’obbiettivo del progetto di dottorato è lo sviluppo di modellistica idraulica a supporto dei processi gestionali delle reti di distribuzione idropotabile. La modellistica va ad integrarsi nel framework gestionale origAMI, che supporta la gestione operativa, economica e della Workflow Management, attraverso l’integrazione di software idraulico, strumenti previsionali e di Anomaly Detection. In questo lavoro sono state approfondite le azioni ed i criteri necessari alla costruzione dei modelli digitali delle reti di distribuzione, presentando diversi casi applicativi che hanno raggiunto diversi livelli di dettaglio e maturità. Sono approfondite le procedure di stima delle prestazioni mediante indici sintetici e misure surrogate, approfondendo concetti come l’affidabilità e la resilienza delle reti. È inoltre presentato un approccio metodologico che si integra nei modelli di progettazione ed ottimizzazione delle infrastrutture di trasporto della risorsa idrica. Tale approccio permette una modellazione più realistica dell’orografia reale introducendo la possibilità di imporre vincoli territoriali ed idraulici nella ricerca degli schemi progettuali. The human society and production processes evolution is increasing the world's water needs. The water resource is unevenly distributed and is undergoing a progressive reduction due to the ongoing climate changes. The need to more carefully manage and optimize the integrated water system makes it necessary to use tools made available by new technologies, which must collaborate in multidisciplinary and integrated management. Current Italian and European regulations underline this need, prescribing the use of specific electronic tools for the design and creation of standardized and easy-to-access territorial databases. The goal of the PhD project is the development of hydraulic modelling to support the management processes of drinking water distribution networks. The modelling is integrated into the origAMI management framework, which supports operational, economic and workflow management, through the integration of hydraulic software, forecasting and anomaly detection tools. In this work, the actions and criteria necessary for the construction of digital models of distribution networks have been studied in-depth, presenting various application cases that have reached different levels of detail and maturity. Performance estimation procedures are explored using synthetic indexes and surrogate measures, deepening concepts such as network reliability and resilience. The thesis presents a methodological approach integrated into the design and optimization models of water resource transport infrastructures. This approach allows more realistic modelling of the real orography by introducing the possibility of imposing territorial and hydraulic constraints in the search for design schemes.
Experimental investigation of system performance for combined desalination processes with membrane capacitive deionisation (MCDI)
(Università della Calabria, 2021-10-31) Cañas Kurz, Edgardo E.; Critelli, Salvatore; Gabriele, Bartolo; Figoli, Alberto; Hoinkis, Jan
The water supply in many coastal regions worldwide is affected by progressive salinization. Here, the use of desalination technologies is a viable solution for obtaining freshwater. In this thesis, two modular concepts for brackish water (BW) desalination by the use of membrane capacitive deionization (MCDI) and low-pressure reverse osmosis (LPRO) were developed and tested at laboratory and pilot-scales with two pilot plants installed in Vietnam. The two concepts were developed by using computer-based calculations (software: WAVE) and evaluated in a socioeconomic and environmental multi-criteria analysis. The first plant consisting of subsurface arsenic removal (SAR) as pre-treatment and MCDI for desalination was installed in Tra Vinh, in the Mekong Delta for the treatment of arseniccontaminated groundwater with a concentration of total dissolved solids (TDS) of 1.65 g/L. Results showed the feasibility of the modular concept for producing drinking water (TDS<0.45 g/L) with a specific energy consumption (SEC) of <3 kWh/m³. The relationship between feed salinity and specific ion removal of the MCDI was evaluated in real environment and compared with laboratory experiments. The use of renewable energies such as solar and wind for autonomous supply was proven feasible for these technologies. The second pilot plant was installed in a riverine estuary in the region of Cần Giờ, where no access to freshwater is available due to the progressive salinization of river water and groundwater. Here, river water showed TDS concentrations of up to 25 g/L. The combined system consisted of UF pre-treatment, LPRO and MCDI to produce drinking water and product water with TDS of <0.45 g/L and <1.5 g/L, respectively with a total SEC of 5.8 kWh/m³. Additionally, the performance of the LPRO was compared to seawater-RO (SWRO) in pilot trials, which showed a SEC of 5.5 kWh/m³. Although the SEC of single-stage SWRO was lower, the separate production of drinking and product water by LPRO+MCDI showed different advantages including a reduced SEC of 5.2 kWh/m³ for product water and additional 0.6 kWh/m³ for drinking water. Finally, an optimization of the LPRO+MCDI can be possible by increasing the desalination efficiency of the MCDI, increasing the efficiency of LPRO-pump and the MCDI power supply, and by aiming at feed water qualities with lower salinity.
Facies analysis and fluid inclusion studies of the Messinian evaporites, Calabria, Southern Italy
(Università della Calabria, 2020-03-26) Cipriani, Mara; Critelli, Salvatore; Costanzo, Alessandra; Dominici, Rocco
Messinian salinity crisis (MSC) is, from about 30 years, one of the most important and debated topic in the scientific community, both in environment and economic field. In this context, Calabrian evaporite deposits, poorly investigated in the past, offer an interesting opportunity to expand the knowledge because they confirm and increase the models created for other Mediterranean basins, and add important information on the main halite and gypsum facies. In this regard, saline evaporitic facies outcropping in the Crotone, Catanzaro and Ionic Basins were investigated using a multidisciplinary approach from classical petrography, to the study of fluid inclusions (FIs) to isotopic geochemistry. (A) The halite samples from the Crotone Basin have highlighted three primary facies; two known in the literature as banded and white while the third, never observed before, called in this work transparent. The transparent facies seems recrystallized but the analyses conducted show instead a primary origin. The three facies form in different environment and with a dissimilar deposition rate (fast or slow) due to pycnocline oscillation (daily or seasonal). Pycnocline oscillations can explain the different temperature of homogenization found within the FIs (from +20° to +33°C). The facies form in a hybrid brine (salinity av. ̴ 26.2 eq. wt% NaCl) enriched in Ca-Mg-Na-K-Cl elements, regardless of their deposition rates. During their fluid inclusions testifying plastic and ductile deformations that don’t remove primary features, demonstrating low recrystallization during burial process. Moreover, isotopic data attribute these facies at the second step of the MSC (5.6-5.5 Ma) during Halite deposition stage in the Mediterranean Basin. (B) The selenite samples from the Catanzaro Trough belong to banded and giant facies. The crystals record middle-frequency climatic oscillation between the depositional cycles and high-frequency climatic oscillation (seasonal) between cloudy and clear microfacies observed within the crystals. These microfacies testify a different brine condition associated with seasonal variation: cloudy intervals form during continental water inflow in the humid phase (Mg and Ca as dominant elements and low salinity values - av. ̴ 3 eq. wt% NaCl), while, clear intervals form in marine water during the arid phase (Na, K and Cl as dominant elements and high salinity values - av. ̴ 21.5 eq. wt% NaCl). Isotopic data attribute these facies at the third step of the MSC (5.5-5.3 Ma) placing, for the first time, the formation of the giant facies at the Upper Gypsum stage in the Mediterranean Basin. (C) The analyses conducted on the gypsum deposit from the Ionian Basin have shown that these crystals do not display primary features. This deposit is an olistostrome. The isotopic data confirm secondary origin attributing these facies at the second step of the MSC (5.5-5.3 Ma) during the Resedimented Lower Gypsum deposition stage in the Mediterranean Basin. The data obtained from the study of the Calabrian Messinian deposits indicate a surprising variety and diversity of evaporitic facies. In this work, it emerges that the formation of, crystals trap primary FIs and microalgae (blue, green and yellow). Primary FIs and organic matters, associated with secondary the different facies is strongly conditioned by climate (wet/arid) and intrinsic characteristics of the basin (depth, arrival of continental water flows etc.) which promote the development of one facies rather than of another.
Fattibilità tecnica, sostenibilità ambientale ed economica di un piccolo impianto di digestione anaerobica installato in Calabria
(Università della Calabria, 2021-11-09) Segreto, Marco; Critelli, Salvatore; Pinnarelli, Anna Ketty; Petracchini, Francesco
Geochemical modelling of natural contaminants in groundwaters and their removal by membrane processes
(Università della Calabria, 2021-10-25) Fuoco, Ilaria; Critelli, Salvatore; Apollaro, Carmine; Marini, Luigi; Bartolo, Gabriele; Figoli, Alberto; De Rosa, Rosanna
The presence of harmful elements dissolved in groundwaters represents one of the main environmental issues of present times. The aim of my PhD Thesis was to study the rock-to-water release and the fate of some inorganic pollutants dissolved in the groundwaters of the Calabria Region, and sometimes in other Italian areas, as well as to select suitable membrane technologies for their removal based on the acquired geochemical knowledge. Taking into account the peculiar characteristics of the groundwaters of the Calabria Region, three elements were considered: arsenic (As), fluorine (F) and chromium (Cr). The salient results of my PhD studies are presented in this Thesis, which is organized in four self-consistent Chapters structured as follows. Chapter 1. Geochemical modelling of As and F release into the crystalline aquifers of the Calabria Region. This section has been devoted to understanding the water-rock interaction processes occurring in the crystalline aquifers of the Calabria Region. Three different reaction path modeling exercises of granite dissolution were performed, reconstructing the water-rock interaction processes which occur: (i) in shallow and relatively shallow crystalline aquifers in which no As and F anomalies were observed; (ii) in As-rich areas, coupling the reaction path modeling of granite dissolution with the simulation of the adsorption of dissolved As onto precipitating crystalline and amorphous hydrous ferric oxide (HFO); (iii) in deep crystalline aquifers where high F concentrations were detected. A total of 160 water samples discharging from the crystalline aquifers of the Calabria region were used to fix the boundary conditions as well as to validate the outcomes of geochemical modeling. The results of the three geochemical modeling exercises of granite dissolution are in agreement with the analytical data and, therefore, it is reasonable to assume that they reproduce satisfactorily the water-rock interaction processes occurring during the travel of meteoric waters from shallow to deep crystalline aquifers, hosted both in granite rocks without mineralizations and in mineralized granites. Moreover, based on the results of the geochemical survey, some As- and F- rich groundwaters were selected and used as feeds for the treatment tests. Some relevant results have been already published by Fuoco et al. (2021a). Chapter 2. Geochemical modelling of Cr(VI) release into the ophiolite aquifers of Italy. This section has been focused on the water-rock interaction processes occurring in the main ophiolite aquifers of Italy. The obtained results were already published by Apollaro et al. (2019a). Reaction path modelling of serpentinite dissolution was performed varying the Fe2O3/(FeO +Fe2O3) weight ratio of serpentine and reproducing the analytical concentrations of relevant solutes, including Cr(VI), in the Mg-HCO3 groundwaters hosted in the ophiolite aquifers of Italy. The occurrence of geogenic Cr(VI) in these groundwaters appears to be potentially controlled by the oxidation of trivalent Cr to the hexavalent redox state, driven by the reduction of trivalent Fe to the divalent redox state. In fact, trivalent Fe is the only oxidant present in suitable amounts in serpentinite rocks, and even serpentine contains high contents of trivalent Fe as proven by recent studies. In contrast, the generally accepted hypothesis that geogenic Cr(VI) in waters interacting with serpentinites is driven by the 2 reduction of trivalent and tetravalent Mn is questionable. To validate the outcomes of the geochemical modeling of serpentinite dissolution and rock-to-water release of Cr(VI), the redox state of Fe in serpentine minerals of different Italian areas was measured (see next section). Moreover, the water sample characterized by the highest concentration of Cr(VI) was selected for the treatment tests. Chapter 3. Determination of the iron redox state in serpentine minerals by using TEMEELS analysis and its environmental implications. This section has been addressed to determine the Fe3+/FeT ratio of the serpentine minerals hosted in five serpentinite samples coming from the main ophiolite areas of Italy, in order to validate the results of the geochemical modeling of serpentinite dissolution and rock-to-water release of hexavalent chromium (see previous section). The electron energy-loss spectroscopy (EELS) combined with transmission electron microscopy (TEM) was selected as most suitable analytical technique because it provides the highest spatial and energy resolution allowing to obtain a good qualitative and quantitative information on iron redox speciation compared to other analytical techniques. Ten site-specific TEM foils were prepared and analyzed in the laboratories of the GFZ German Research Centre for Geosciences, in Potsdam. It has not been the simple application of a well-established analytical technique, but rather a challenging study, because it has been necessary to develop a new spectra processing method and prove its validity. The performed analyses provided in-depth knowledge on nanoscale structures of the studied samples and showed that Fe3+ represents from 75 to 85 % (median values) of total iron. The obtained results provide further support to the hypothesis concerning the oxidation Cr(III) to Cr(VI) driven by the concurrent reduction of Fe(III) to Fe(II), as suggested by geochemical modeling (see previous section). Chapter 4. Application of membrane processes to remove As, F and Cr(VI) from contaminated groundwaters. This section has been devoted to the removal of As, F and Cr from polluted groundwaters by means of membrane processes. Relevant results have been already published by Figoli et al. (2020), Fuoco et al. (2020) and Fuoco et al. (2021b). The geochemical approach was used as strong-scientific tool for pre-selection of suitable remediation systems and the contaminated groundwaters were chosen from the previous data collections. Several type of commercial nanofiltration/reverse osmosis membranes, not already tested in the pertinent literature, were selected depending on the type of application. Their efficiency was evaluated in terms of arsenic, fluoride and chromium rejection, water production and feed composition. The other main ions that contribute to water chemistry were also taken into account to evaluate the possible intended use of the considered waters after the treatments. Satisfactory results were obtained for each specific case of contamination. Moreover, an innovative membrane with absorbent capacities against As(III) and As (V) species was developed and the preliminary results are quite promising. Summing up, the findings obtained in this work are useful for the understanding of the rock-to-water release of the chemical elements of interest and their fate in natural waters. Moreover, the treatment of natural As, F, and Cr-contaminated groundwaters improved the knowledge and the data availability for future scientific and application developments in similar geological settings worldwide.
Geologia e stile strutturale della Falda di Cariati e della Stretta di Siderno al margine pedemontano peri-ionico, Calabria centrale e meridionale: implicazioni sull’evoluzione paleogeografica e paleotettonica
(2013-11-04) Tripodi, Vincenzo; Critelli, Salvatore; Muto, Francesco; Russo, Franco
Geological and structural evolution of tectonically active areas of the central Calabria Arc
(2016-03-04) Brutto, Fabrizio; Pantano, Pietro; Muto, Francesco; Loreto, Maria Filomena; Critelli, Salvatore
The Catanzaro Trough is a Neogene-Quaternary basin developed between the Serre and the Sila Massif, filled by up to 2000 m of Upper Miocene to Quaternary sedimentary succession, belonging to the central Calabrian Arc and extended from offshore, Sant’Eufemia Basin (SE Tyrrhenian Sea), to the onshore, Catanzaro Basin. By joining on land geo-structural with marine geophysical data, we performed a detailed analysis of processes that during last 5 My have controlled the evolution of western portion of the Catanzaro Trough. The fieldwork study, focused on the onshore area, has allowed to acquire more than 700 fault planes, classified on the base of kinematics and fault directions, whereas the geophysical data (sub-bottom, multi- and mono-channel seismic profiles), coming from some scientific cruises within the Sant’Eufemia Gulf (SE Tyrrhenian Sea), gave us the opportunity to reconstruct the tectono-stratigraphic evolution of the offshore area. The combination amongst abrupt sea level changes, transpressional and trans/extensional tectonics and back-arc Tyrrhenian subsidence during SE-drifting of Calabrian Arc controlled sedimentary basin hosted by the Catanzaro Trough, as the result we have recognized three tectonic events formed in the Upper Miocene- Zanclean, Piacezian-Lower Pleistocene, and Middle-Upper Pleistocene. The data analysis provide information about stratigraphy and tectonics in the strata and also give some indication of the tectono-stratigraphic architecture. Sedimentary basin, in fact, looks to be mainly controlled by the activity of NW–SE and NE–SW oriented fault systems. The NW-SE oriented faults showing strike slip and oblique kinematics can be considered responsible for the opening of a WNW–ESE paleo-strait connecting the Tyrrhenian Sea with the Ionian Sea during multi-phases tectonics that have acted in the study area since Miocene. The integrated geo-structural and geophysical data show a change from left-lateral to right-lateral kinematics during Piacezian-Lower Pleistocene, as the result of a change of the stress field. Since Middle Pleistocene, the study area experienced an extensional phase, WNWESE oriented, controlled mainly by NE-SW and subordinately N-S oriented normal faults, which split obliquely the western Catanzaro Trough, producing up-faulted and downfaulted blocks, arranged as graben-type systems, extending from onshore to offshore area. In agreement with and Jacques et al., (2001) and Presti et al., (2013), the NE-SW and NS trend normal faults play a relevant role as part of recent seismotectonic processes controlling the Late Quaternary geodynamic of the central Calabrian Arc, representing the source of the main destructive earthquakes occurred in the area. Thanks to these multidisciplinary approach we are able to provide a more reliable and detailed structural frame of the central Calabria segment, providing new elements about recent activity of faults, and giving a further contribution for the seismogenetic potential assessment of an area historically considered with the highest earthquake and tsunami risk throughout Italy.
<> sintomi comportamentali e psicologici nella malattia di Alzheimer: esordio e differenze di genere
(2018-05-11) Altomari, Natalia; Critelli, Salvatore; Passarino, Giuseppe; Bruni, , Amalia C.
BPSD have a deep physical and psychological impact on patients affected by any kind of dementing illness and on caregiver in terms of costs and resources and represent an important cause of institutionalization. The aim of the study was to investigate the occurrence of BPSD in a sample of patients with Alzheimer’s disease in three stages: preclinical (TO), from AD onset to five years (T1) and for five years onwards (T2). Furthermore, possible differences between men and women and Early and Late Onset Alzheimer’s disease (EOAD and LOAD) have been analyzed. 1925 medical records of AD patients, diagnosed with NINCDS-ADRDA, criteria have been examined from the digital database of the Regional Neurogenetics Center (ASP-CZ). Symptoms have been extracted from Neuropsychiatric Inventory (NPI) and from a check list of BPSD for internal use for as long as BPSD have been observed(apathy, irritability, depression, anxiety, delusions, hallucinations, aggression, agitation, disinhibition, affective lability, wandering, sleep disorders and eating disorders). At least one BPSD was detected in 90,4% of the sample. The most represented symptoms were apathy (57.4%), irritability/affective lability (50.5%) and agitation/aggression (42.3%), the last two were presented especially in men (p = 0.000). Most of BPSD are distributed between the fourth and fifth year of illness. According to gender, disinhibition appears significantly later in women and according to onset all BPSD manifest significantly later in patients with EOAD. Concerning differences between EOAD and LOAD patients, sleep disorders characterize EOAD in preclinical stage (p=0.022). Depression (p=0.017) is predominant in EOAD at T1, while LOAD presents with more irritability/affective lability (p=0.000), agitation/aggression (p=0.001) and sleep disorders (p=0.000). A considerable number of EOAD patients still develop BPSD in the advanced stage (T2). As regard gender, considering BPSD timing, depression characterizes women in preclinical stage (T0) (p=0.01). At T1 men show disinhibition (p=0.002) irritability/affective lability (p=0.000), sleep disorders (p=0.03), agitation/aggression (p=0.000) while women exibit greater anxiety (p=0.027) and depression (p=0.000). No gender differences have been evidenced in T2. Behavioral and Psychological Symptoms in our cohort demonstrates, in agreement with the literature how AD is not only “a cognitive” disease. Interestingly, a number of signs of behavioral changes appear before AD onset. The identification of these “red flags” of AD can be important and significant for the early detection of the disease. Predominance of affective pattern in women and aggressivity in men suggests that gender differences can be related to a brain’s pathophysiological diversity. Therefore, a strategic and adaptive management of these symptoms is always necessary to early diagnose, cure and care patients with this devastating brain disorder
Impianto Syndial-Eni di Cirò Marina (Kr): analisi geologica, ambientale e valutazione del livello del rischio (D.Lgs 81/2008)
(2018-05-11) Spezzano, Luigi; Critelli, Salvatore; Barca, Donatella; Macario, Anastasia
Innovative composite membranes for advanced applications
(2019-05-10) Grasso, Giuseppe; Critelli, Salvatore; Gabriele, Bartolo
Presented thesis work is mainly focused on coatings preparation, their potentiality and applications in membrane science: from water desalination to antibiofouling membranes, to gas separation. In fact, coating preparation represents an useful and versatile technique which allows a fine control of membrane properties and performance such as chemical or physical resistance, durability, etc. One of major drawbacks is represented by production costs, which can become important in scale-up operations. Therefore, although several type and methodologies for coating preparation are known and reported in literature, a lack of cheap, efficient and scale-up adaptable coating methods made their different preparation methods of particular interest. The results presented herein, concern the preparation of three different coating methods whose applications are briefly summarized below:  Chapter 2: Development of PVDF-f-Graphene Thin Film Composite Membrane for Membrane Distillation Chapter 2 reports a novel method for TFC membrane fabrication, using graphene layer coated on chemically-functionalized PVDF. PVDF is hydrophobic polymer whose properties are well suited for those applications in which hydrophobicity is needed such as Membrane Distillation. In order to increase adhesion between PVDF and graphene, we co-polymerized PVDF with a suitable monomer bearing aromatic part, using a procedure which involves 2 steps reaction: introduction of double bonds on polymer backbone by basic treatment followed by its reaction with monomer through radical reaction. Membranes have been prepared using functionalized PVDF polymer (PVDF-f) and tested on Direct Contact Membrane Distillation (DCMD) apparatus at first. Subsequently tests were conducted using PVDF-f-Graphene composite membrane, using graphene synthetized using Chemical Vapor Deposition ( CVD) method. Created membranes were analyzed and their chemical, physical and morphological properties were investigated. Membranes made using PVDF-f polymer exhibited good flux and salt rejection (up to 99.9 %), whereas graphene association to PVDF-f membranes leads to lower water flux but higher rejection and durability (up to 99.99 %). In chapter 3 a simple and innovative synthetic strategy for Acryloyloxyalkiltriethyl ammonium salts surfactants (AATEABs) starting from cheap and easily available chemicals is discussed. Herein reported surfactants can be used as coating for membranes to whom they confer high anti biofouling properties. Synthetic procedure was first optimized in order to work avoiding prohibitive conditions such as Inert atmosphere or high temperature and then applied to the synthesis of surfactants bearing a different alkyl-chain length. Antibacterial activity evaluation, has been done performing several tests against Gram +\- and yeast strains; results confirmed that AATEABs bearing C11 (AUTEAB) and C12 (ADTEAB) alkyl chain possess highest activity which is remarkable high for ADTEAB. AATEABs may find applications as polymerizable coatings for watr-treatment membranes ( commercial or not) to be used in Pressure-Driven Membrane Processes or in any other membrane-based system in which antifouling properties may play an important role.  Chapter 4: Thin Film Composite Membrane fabrication for gas separation: Defect control and bench-scale demonstration Fourth chapter of this thesis work, concerns the preparation of TFC membranes to be used for CO2/N2 separation, on the relationship between TFC membrane material and membrane properties and the role of the protective layer in determining the amount of defects, which is a crucial aspect for all the gas separation-related processes. We report a simple and efficient procedure which can also be applied to for defect controlling during scale-up process and which is not valid for CO2 separation membranes only. Results demonstrate a correlation between the properties of protective layer and separation performances: in particular, the possibility to apply a coating film on commercial membrane permits the creation of membranes in which the amount of defect is dramatically reduced. Another crucial aspect discussed in chapter 4 concerns the thickness of protective layer used for defect control: in fact, whereas the presence of protective layer plays an important role defect-free membrane creation process, its thickness impacts on separation operation. With our method, the preparation of membranes with very thin protective layer ( 0.1 μm or below) is possible.