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Item Applicazione dei big data nel turismo, marketing ed education(Università della Calabria, 2020-03-18) Giglio, Simona; Critelli, Salvatore; Pantano, PietroIl 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.Item 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, CarmelinaLa 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.Item 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, RoccoMessinian 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.Item 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, AnnaThe 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.Item 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, FrancescoItem 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, GiuseppeVulnerability 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.Item 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, PaoloStill 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.Item New Catalyzed Approaches For The One-Step Synthesis Of High Value-Added Products(Università della Calabria, 2021-10-28) Amuso, Roberta; Critelli, Salvatore; Gabrele, Bartolo; Veltri, LuciaHeterocyclic compounds play an important role in synthetic and bioorganic chemistry, as they represent a structural motif in a large number of biologically active natural and non-natural compounds. The synthesis of new heterocycles possessing biological activity and the development of innovative and accessible synthetic pathways are currently a very widespread research area. In the present PhD thesis is reported the development of new synthetic, simple and innovative methodologies in one step for the direct formation of high value-added compounds by the catalytic activation of simple building blocks, CO and CO2. CO is a simplest and most available C-1 unit, which meets the requirements of “atom economy”, step economy and “green chemistry”; the possibility to synthesize molecules of important pharmacological interest by a direct carbonylation procedure involving the use of carbon monoxide represent a very attractive alternative synthetic approach. CO2 is the main component of greenhouse gases, responsible for the increase in the earth's temperature and anomalous climate changes. Thus, post-combustion COIn fact, carbon dioxide can be considered as a ubiquitous, cheap, abundant, non-toxic, non-flammable and renewable C1 source, which has great importance from the viewpoint of both environmental protection and resource utilization. In the first chapter is reported a new example of an additive cyclocarbonylation process leading to 1-thia-4a,9-diazafluoren-4-ones, an important class of polyheterocyclic compounds known to possess important pharmacological activities. Part of this PhD was spent at Leibniz Institute for Catalysis in Rostock University. Here, ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N-bound ligands have been prepared and fully characterized for the first time. The advantages of the new catalysts are demonstrated in the general green α-alkylation of ketones with alcohols following a hydrogen autotransfer protocol. Furthermore, other cyclometalated ruthenium complexes bearing bidentate ligand were obtained for methylation of anilines with methanol to selectively give N-methylanilines. The hydrogen autotransfer procedure has been applied under mild conditions (60 °C) in a practical manner (NaOH as base).2 capture and its conversion into high value-added chemicals are integral parts of today’s green energy industry.Item Synthesis and cherization of low-dimensional materials(Università della Calabria, 2020-04-16) Alessandro, Francesca; Critelli, Salvatore; Caputi, Lorenzo; Cupolillo, AnnaThe main aim of this thesis is to synthesize and study low-dimensional materials, with special focus on: silicene, PtTe2, carbon nano-onions and activated carbon. The first section of this work describes the study of the collective modes in silicene and PtTe2. Silicene, the silicon equivalent of graphene, is attracting increasing scientific and technological interest in view of the exploitation of its exotic electronic properties. This material has been theoretically predicted to exist as a free-standing layer in a low-buckled, stable form, and can be synthesized by the deposition of Si on appropriate crystalline substrates. Using a combined experimental (High-Resolution Electron-Energy-Loss Spectroscopy, HR-EELS) and theoretical (Time Dependent Density Functional Theory, TDDFT) approach the electronic excitations of two phases of silicene growth on silver were studied showing that silicene grown in a mixed phase on Ag(111), preserves part of the semimetallic character of its freestanding form, exhibiting an interband π-like plasmon. Recently, the PtTe2 has emerged as one of the most promising among layered materials ―beyond graphene‖. In this work, the electronic excitations of the bulk PtTe2 were investigated by means of EELS and DFT detecting a sequence of modes at 3.9, 7.5 and 19.0 eV. The comparison of the excitation spectrum with the calculated density of states (DOS) allowed to ascribe spectral features to transitions between specific electronic states. Moreover, it has been observed that, in contrast to graphene, the high-energy plasmon in PtTe2 gets red-shifted by 2.5 eV with increasing thickness. The second section of this thesis reports the synthesis of polyhedral carbon nano-onions by arc discharge in water and the electrochemical performance of activated carbon in aqueous electrolytes. CNOs, in their spherical or polyhedral forms, represent an important class of nanomaterials, due to their peculiar physical and chemical properties. In this work, polyhedral carbon nano-onions (CNOs) were obtained by underwater arc discharge of graphite electrodes using an innovative experimental arrangement. Dispersed nanomaterials and a black hard cathodic deposit were generated during the discharges and studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and thermogravimetric analysis (TGA). A model for the formation of the deposit was proposed, in which the crystallization is driven by an intense temperature gradient in the space very close to the cathode surface. Electric double layer capacitors (EDLC) are gaining increasing popularity in high power energy storage applications. Novel carbon materials with high surface area, high electrical conductivity, as well as a range of shapes, sizes and pore size distributions are being constantly developed and tested as potential supercapacitor electrodes. In this thesis, the electrochemical behavior of a highly microporous activated carbon was studied as electrode for symmetric and asymmetric capacitors in acid and neutral media. The highest capacity and energy density values were obtained in the case of the activated carbon in acid solution.Item Valorisation of plastic wastes from electrical and electronic equipment (WEEE) containing PVC by MFI-zeolites mediated catalytic pyrolysis(Università della Calabria, 2022-02-02) Marino, Alessia; Critelli, Salvatore; Giordano, Girolamo; Serrano, David P.