Dipartimento di Ingegneria Meccanica, Energetica e Gestionale - Tesi di Dottorato
Permanent URI for this collectionhttps://lisa.unical.it/handle/10955/100
Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento di Ingegneria Meccanica, Energetica e Gestionale dell'Università della Calabria.
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Item Development of a CAE-basedapproach for the concurrent design, manufacturing and testing of hybrid metal-composite spur gears(Università della Calabria, 2020-02-19) Catera, Piervincenzo Giovanni; Furgiuele, Franco; Mundo, Domenico; Treviso, AlessandraTrends in emission limitations and fuel efficiency impose a more efficient energy exploitation in many application fields of mechanical systems. In this direction, the lightweighting of mechanical structures represents a powerful strategy, above all in the transportation industry, where geared transmissions play a key role. Here, these components are designed in such a way that performance criteria are met at the minimum weight, without compromising the requirements of reliability and safety. In this context, the aim of the present work is the development of new strategies for the design of geared systems, where the concept of gear body lightweighting with geometrical modifications is substituted by the one applied to the material, in order to improve the strength-to-weight ratio and reduce vibrations in the overall mechanical system. In particular, the research is focused on innovative methods for the simulation, manufacturing and testing of a hybrid gear, in which a metal rim is joined with a composite body. In detail, the contribution of the gear body stiffness is studied by means of a multi-scale approach, which starts from the interaction between matrix and fibres at the micro-scale to derive the lamina properties at the macro-scale. In this way, the anisotropy of the composite material can be accounted for, leading to an accurate modelling and evaluation of the mechanical properties of the gear. Additionally, two assembly techniques are used for joining the rim part to the body, which include adhesive bonding and interference fitting. Both techniques are analysed with experimental modal tests to characterize dynamic stiffness and damping in comparison to a lightweight metal gear with the same mass. At the same time, non-linear finite element (FE) simulations are executed for the evaluation of the static transmission error and meshing stiffness. Finally, the last part of the work deals with the experimental analysis of a hybrid gear pair during meshing in a dedicated test-rig, where the dynamic behaviour is analysed with respect to the variation of applied torque and rotational velocity. Noise and vibration behaviour of a solid-hybrid gear pair is compared to that of a pair composed by a solid and a lightweight metal gear. Experimental results show the great potentiality of the multi-material approach in mechanical power transmissions.Item Toughening mechanisms and damage tolerance of bioinspired interfaces(Università della Calabria, 2020-03-06) Morano, Chiara; Furgiuele, Franco; Alfano, MarcoBiologically inspired designs were deployed into selective laser sintering of polyamide substrates to study the mechanics of adhesion and debonding of adhesive bonded structural interfaces. In particular, through extensive series of experiments and simulations, the present study covers the effect of hollow channels, mimicking the base plate of the Amphibalanus amphitrite, and of sinusoidal interfaces, resembling those observed in sutures joints, on the mechanics of crack propagation in adhesive bonds. A model material system comprising adhesively bonded 3D printed substrates in the Double Cantilever Beam (DCB) configuration was selected for the analyses. Adhesive bonding and subsequent mechanical tests revealed the occurrence of a crack trapping effect, which hinders crack propagation and enhances energy dissipation with respect to the baseline interface. The use of bioinspired structures is shown to improve the performances of adhesive joints, enabling damage tolerance and, in the case of subsurface channels, also a weight reduction. Numerical simulations, carried out using finite element analysis (FEA) with interface elements, were also executed to gain a deep understanding of all mechanisms observed experimentally. The simulations were able to mimic the serrated behavior observed in experimental load-displacement responses, which was due to the snap-through interfacial cracking mechanism, i.e., a sudden and almost instantaneous growth of apparently stable cracks. Moreover, the mechanisms of fracture observed in the experiments (e.g., nucleation of a secondary crack at the interface) were reproduced with good accuracy in finite element simulations. The overall analysis demonstrates that is possible to improve joints effective fracture toughness by modifying joints architecture, even without any modification of adhesive type and/or interface properties (e.g., surface energy). This study further confirms that additive manufacturing represents a powerful platform for the experimental study of bio-inspired materialsItem Turismo e beni culturali in Calabria: strategie di sviluppo basate sull’innovazione tecnologica(Università della Calabria, 2020-03-10) Skrame, Aurora; Furgiuele, franco; Muzzupappa, MaurizioMy research was inspired by the analysis of the use of historical and cultural heritage in the Calabrian territory and by the evidence of the difficulties encountered in this. The use of historical and cultural heritage in Calabria is clearly less than in all other regions of Italy, despite the quantity and quality implicit in the offer. Most of the urban stratifications of the ancient nuclei are little known to classical tourism and to the population itself. In an area where only 20% of the surface is not historically populated, this is a situation that raises important questions and requires solutions. Tourism is a complex field, if the use does not reach the destination it is evident that one or more elements of the system do not work, do not collaborate or are not active. The identification and analysis of the gap between the strategies of the intervention plans and their application on the Calabrian territory was the starting point of this research. The aim of the research was therefore to deepen a complete methodology aimed at defining an effective and efficient "tourism product prototype", a project aimed at enhancing the Calabrian historical-archaeological heritage, focused on the most advanced virtual technology and integrated into the network. of existing services, to be amplified and improved, as a model to be reproduced in similar contexts, on the Calabrian territory. - To achieve this goal, I articulated and defined the research activity into three phases: The first analysis phase investigated three specific aspects: - In-depth study of the best examples and management strategies of tourism services and DMO (Destination Management Organization) operating in the field of historical-cultural heritage in Europe and in Italy, and identification of examples of good practices for an ideal DMO on the Calabrian territory according to the European reference quality parameters and indicators. - Study of regional and ministerial financing programs in the field of cultural tourism and infrastructure services in the Calabrian territory capable of supporting a specific project and the actors currently engaged in the territory. - Study of the best technological solutions in the context of the use of historical assets and the possible application on Calabrian archaeological areas and museums. The results I obtained from the first study phases described above have made it possible to identify the main critical issues of the infrastructural system, of the services in the field of cultural tourism and in particular have highlighted the absence in the application of innovative technologies that could expand in a way educational but also pleasant the offer linked to cultural heritage, involving new and more numerous users. Consequently I concentrated the second phase of the thesis work on the definition of an integrated and global intervention project (now become a Strategic Project financed by the Calabria Region and MIbac) which concerns the Ionian coast. It is obviously a highly symbolic territory (we are in Magna Grecia), one of the oldest and most precious testimonies of historical stratification in Italy, as well as the area with the highest concentration of sites that can be visited but little explored among the Italian ones (with a evident deficit in terms of attractiveness). The statistical-historical survey on the use of the area's sites (obtained from Istat and MIbac data) relegates it to the lowest places in the Italian ranking, with attendance that is limited to a few "lovers" or visits organized by schools. The seaside tourist potential of the Ionian belt is known but this is not absolutely integrated with the availability of areas and archaeological museums. My strategic proposal, third phase of the innovative activity of its kind, is divided into two phases: the coordination of the active rail transport service, with a new road passenger transport service (on call), which covers the entire Calabrian Ionian belt, from the station of Sibari to that of Bova, which involves the archaeological parks and museums of six distinct cultural tourist destinations; and the improvement of the cultural offer to visitors in each of the destinations, through didactic activities, projections and reconstructions usable in multiple ways based on virtual reality and the possibility to assist and participate in the excavation and recovery activities in the currently active archaeological sites, with itineraries customized for different categories of visitors. The media coverage promoted and curated by the Calabria Region, MIbac and FS, ensures a continuous tourist flow during the year. The final phase of the doctoral activity therefore concerns the definition of the integrated strategic model for the use of improvement technologies for one of the historical areas covered by the strategic project proposal. In detail, it is the design of a technologically advanced intervention of the route inside the archaeological site of Locri, in a more "user-oriented" rather than "expert-oriented" perspective. This approach aims to bring younger generations closer to the knowledge of historical and cultural heritage. To this end, I analyzed the results of the surveys planned and carried out with the various school groups in the last 3 years, with different universities, to identify the degree of interest and preferences towards multimedia technologies applied to historical heritage. Based on the results of the latter, I have developed a project of reconstruction and real navigation on the entire archaeological area of Locri Epizephiri, and in detail on its three most significant monumental buildings. The innovative approach of this research lies in having applied the in-depth knowledge of various fields of study such as architecture, history and engineering to find interdisciplinary solutions to the needs of critical issues emerging in the area of interest, of which; humanistic / archaeological knowledge applied to the study of historical assets and finds, the skills in the field of transport management applied to the organization of an integrated plan for the transport of people, the notions of project management to connect and organize the services of the various stakeholders in the urban area, the timing and the economic framework, the principles of civil and management engineering for the various processes related to the management of 3D technology and for reconstituted environments, with a view to global use, knowledge of history and architecture for the harmonious elaboration of the elements and insertion in the current setting. could expand in a way educational but also pleasant the offer linked to cultural heritage, involving new and more numerous users. Consequently I concentrated the second phase of the thesis work on the definition of an integrated and global intervention project (now become a Strategic Project financed by the Calabria Region and MIbac) which concerns the Ionian coast. It is obviously a highly symbolic territory (we are in Magna Grecia), one of the oldest and most precious testimonies of historical stratification in Italy, as well as the area with the highest concentration of sites that can be visited but little explored among the Italian ones (with a evident deficit in terms of attractiveness). The statistical-historical survey on the use of the area's sites (obtained from Istat and MIbac data) relegates it to the lowest places in the Italian ranking, with attendance that is limited to a few "lovers" or visits organized by schools. The seaside tourist potential of the Ionian belt is known but this is not absolutely integrated with the availability of areas and archaeological museums. My strategic proposal, third phase of the innovative activity of its kind, is divided into two phases: the coordination of the active rail transport service, with a new road passenger transport service (on call), which covers the entire Calabrian Ionian belt, from the station of Sibari to that of Bova, which involves the archaeological parks and museums of six distinct cultural tourist destinations; and the improvement of the cultural offer to visitors in each of the destinations, through didactic activities, projections and reconstructions usable in multiple ways based on virtual reality and the possibility to assist and participate in the excavation and recovery activities in the currently active archaeological sites, with itineraries customized for different categories of visitors. The media coverage promoted and curated by the Calabria Region, MIbac and FS, ensures a continuous tourist flow during the year. The final phase of the doctoral activity therefore concerns the definition of the integrated strategic model for the use of improvement technologies for one of the historical areas covered by the strategic project proposal. In detail, it is the design of a technologically advanced intervention of the route inside the archaeological site of Locri, in a more "user-oriented" rather than "expert-oriented" perspective. This approach aims to bring younger generations closer to the knowledge of historical and cultural heritage. To this end, I analyzed the results of the surveys planned and carried out with the various school groups in the last 3 years, with different universities, to identify the degree of interest and preferences towards multimedia technologies applied to historical heritage. Based on the results of the latter, I have developed a project of reconstruction and real navigation on the entire archaeological area of Locri Epizephiri, and in detail on its three most significant monumental buildings. The innovative approach of this research lies in having applied the in-depth knowledge of various fields of study such as architecture, history and engineering to find interdisciplinary solutions to the needs of critical issues emerging in the area of interest, of which; humanistic / archaeological knowledge applied to the study of historical assets and finds, the skills in the field of transport management applied to the organization of an integrated plan for the transport of people, the notions of project management to connect and organize the services of the various stakeholders in the urban area, the timing and the economic framework, the principles of civil and management engineering for the various processes related to the management of 3D technology and for reconstituted environments, with a view to global use, knowledge of history and architecture for the harmonious elaboration of the elements and insertion in the current setting.could expand in a way educational but also pleasant the offer linked to cultural heritage, involving new and more numerous users. Consequently I concentrated the second phase of the thesis work on the definition of an integrated and global intervention project (now become a Strategic Project financed by the Calabria Region and MIbac) which concerns the Ionian coast. It is obviously a highly symbolic territory (we are in Magna Grecia), one of the oldest and most precious testimonies of historical stratification in Italy, as well as the area with the highest concentration of sites that can be visited but little explored among the Italian ones (with a evident deficit in terms of attractiveness). The statistical-historical survey on the use of the area's sites (obtained from Istat and MIbac data) relegates it to the lowest places in the Italian ranking, with attendance that is limited to a few "lovers" or visits organized by schools. The seaside tourist potential of the Ionian belt is known but this is not absolutely integrated with the availability of areas and archaeological museums. My strategic proposal, third phase of the innovative activity of its kind, is divided into two phases: the coordination of the active rail transport service, with a new road passenger transport service (on call), which covers the entire Calabrian Ionian belt, from the station of Sibari to that of Bova, which involves the archaeological parks and museums of six distinct cultural tourist destinations; and the improvement of the cultural offer to visitors in each of the destinations, through didactic activities, projections and reconstructions usable in multiple ways based on virtual reality and the possibility to assist and participate in the excavation and recovery activities in the currently active archaeological sites, with itineraries customized for different categories of visitors. The media coverage promoted and curated by the Calabria Region, MIbac and FS, ensures a continuous tourist flow during the year. The final phase of the doctoral activity therefore concerns the definition of the integrated strategic model for the use of improvement technologies for one of the historical areas covered by the strategic project proposal. In detail, it is the design of a technologically advanced intervention of the route inside the archaeological site of Locri, in a more "user-oriented" rather than "expert-oriented" perspective. This approach aims to bring younger generations closer to the knowledge of historical and cultural heritage. To this end, I analyzed the results of the surveys planned and carried out with the various school groups in the last 3 years, with different universities, to identify the degree of interest and preferences towards multimedia technologies applied to historical heritage. Based on the results of the latter, I have developed a project of reconstruction and real navigation on the entire archaeological area of Locri Epizephiri, and in detail on its three most significant monumental buildings. The innovative approach of this research lies in having applied the in-depth knowledge of various fields of study such as architecture, history and engineering to find interdisciplinary solutions to the needs of critical issues emerging in the area of interest, of which; humanistic / archaeological knowledge applied to the study of historical assets and finds, the skills in the field of transport management applied to the organization of an integrated plan for the transport of people, the notions of project management to connect and organize the services of the various stakeholders in the urban area, the timing and the economic framework, the principles of civil and management engineering for the various processes related to the management of 3D technology and for reconstituted environments, with a view to global use, knowledge of history and architecture for the harmonious elaboration of the elements and insertion in the current setting.Item Generazione rinnovabile distribuita e nuovi Modelli di Business di Comunità per la transizione energetica del sistema elettrico(Università della Calabria, 2020-03-24) Mendicino, Luca; Critelli, Salvatore; Menniti, Daniele; Sorrentino, Nicola; Pinnarelli, AnnaIl presente lavoro di tesi si occupa dei principali indirizzi a livello nazionale e internazionale sul tema energia per comprendere le nuove traiettorie del sistema elettrico nel medio-lungo periodo e perseguire gli obiettivi di sviluppo delle fonti rinnovabili fissati al 2030-2050. Oltre a riassumere e schematizzare il contesto europeo e nazionale, illustra i fattori impattanti sulle reti elettriche a fronte dei profondi cambiamenti apportati dalla generazione rinnovabile in forma distribuita. Gli aspetti di mercato, i modelli di business per la condivisione dell’energia da parte di finali attivi e le possibili configurazioni hanno rappresentato la parte pratica del lavoro, nella quale supponendo di mettere a sistema utenti finali residenziali secondo uno schema di aggregazione definito da un nuovo modello che prende il nome di comunità energetica, si sono valutati i criteri per la sostenibilità complessiva del modello proposto. L’emergenza climatica e ambientale ha reso inevitabile un cambiamento nella logica di approvvigionamento energetico con l’abbandono dei combustibili fossili ed una transizione verso le fonti di energia rinnovabile indispensabili per la de carbonizzazione del sistema elettrico, comportando un ripensamento nel sistema di distribuzione e consumo dell’energia. Lo studio degli indirizzi strategici globali, europei e nazionali ha mostrato come, gli effetti causati dalle rinnovabili sulle reti elettriche hanno determinato un cambiamento del settore, con una trasformazione della generazione in forma distribuita ed una generale trasformazione degli utenti finali con un ruolo sempre più attivo nel sistema elettrico. Il tema dell’empowerment del consumatore e di una sua attiva partecipazione ai mercati elettrici è uno dei punti cardine delle politiche energetiche a partire dal ‘Clean Energy Package’. Infatti, in materia di energie rinnovabili tale nuovo ruolo del consumatore si traduce letteralmente nei temi dell’autoconsumo, delle collettività di consumatori e degli impianti di generazione rinnovabile. L’analisi dei futuri scenari delle reti, ha evidenziato come il binomio generazione distribuita-utente attivo, attraverso l’autoconsumo del singolo utente nonché in maniera collettiva, è un concetto ben rappresentato dalle Comunità Energetiche che sembra essere la chiave per raggiungere, sia obiettivi climatici posti a livello globale ed Europeo, sia la soluzione a problematiche tecniche dovute alla penetrazione delle rinnovabili nelle reti elettriche. Le aggregazioni di utenti che producono l’energia elettrica necessaria per soddisfare i propri fabbisogni, accumulandola e gestendola al loro interno, esprime infatti una nuova modalità di approvvigionamento e consumo che valorizza le risorse energetiche rinnovabili e distribuite. Tra un proliferare di modelli teorici proposti per la gestione delle reti e degli utenti finali con l’obiettivo di integrare risorse distribuite in un sistema nato per essere centralizzato, si è trattato il modello delle Comunità Energetiche con scambio virtuale di energia tra una pluralità di consumatori e/o autoproduttori. In questo modo l’aggregazione avviene tra utenti che non sono localizzati in uno stesso sito, ma che mettono a disposizione l’energia autoprodotta da fonti rinnovabili per gli utenti della comunità stessa tramite la rete pubblica, con l’ausilio di tecnologie abilitanti, riproducendo quello che sarebbe di un sistema di autoconsumo fisico (in sito) ma valorizzando l’utilizzo della rete pubblica di distribuzione che si configurerebbe come uno dei fattori abilitanti dell’autoconsumo in forma collettiva consentendo di mantenere qualità del servizio e libero accesso agli utenti finali. Sebbene le configurazioni per la creazione di comunità energetiche possano essere diverse si è approfondita quella promossa da un soggetto terzo che aggrega utenti in una numerosità tale da rende fattibile lo schema collettivo. È stato pertanto necessario individuare gli attori coinvolti nel modello di business e gli elementi per definire le voci di costo e ricavo dell’aggregazione prendendo in considerazione alcuni indicatori economici per valutarne la sostenibilità. Si sono costruiti diversi scenari andando a modificare delle variabili ritenute più sensibili (numerosità degli di utenti aggregati, percentuale di autoconsumo e prezzi dell’energia) distinguendo gli scenari per tipologia di utenti aggregati (soli utenti attivi e caso di utenti attivi e passivi), ipotesi di fornitura di servizi alla rete e riduzione degli oneri in favore delle comunità energetiche ipotizzando il recepimento delle recenti direttive europee in ambito nazionale. Si è valutata infine, la riduzione dei costi tecnologici o incentivi in favore delle comunità per ottenere tempi di ritorno più contenuti e almeno paragonabili a quelli di utenti che agiscono in maniera individuale. Sulla base dei prezzi applicati nella comunità, la costruzione di prospetti che replicano la spesa elettrica dell’utente finale nel contesto Italiano ha permesso di valutare oltre agli evidenti benefici sociali e ambientali, i possibili benefici economici ottenibili per gli utenti partecipanti allo schema. Le analisi numeriche hanno mostrato come le condizioni attuali richiedono una consistente numerosità di utenti finali per la realizzazione di comunità dell’energia formate da utenti prosumers, che oscillano tra 4.000-6.500 utenti a seconda delle ipotesi e della configurazione adottata nel modello con tempi di recupero che nello scenario più ottimistico sono di almeno 7 anni. Nella configurazione di comunità adottata, si richiede un livello di autoconsumo del 70%, che può essere favorito dalla progressiva diffusione dei SdA associata ad una sensibile riduzione dei costi delle tecnologie abilitanti. Per raggiungere risultati soddisfacenti e favorirne lo sviluppo, emerge come serve ancora un valido supporto da parte delle politiche comunitarie e incentivi (tra il 55-65%) che possono essere sia in forma implicita che esplicita. L’apertura al mercato dei servizi alla rete (MSD) offerti anche dai piccoli utenti aggregati può essere un ulteriore elemento di supporto anche se al momento presenta difficoltà di acceso per via di una regolazione prematura e di remunerazioni troppo contenute ma, l’introduzione di misure specifiche per le comunità energetiche può spingere ulteriormente alla nascita di questa configurazione. Le comunità energetiche possono avere una miriade di configurazioni che non sempre portano a ritorni nel breve termine e pertanto non devono essere valutate dal solo punto di vista economico, ma vanno prese in considerazione anche ricadute di natura sociale, occupazionale e soprattutto di carattere ambientale. La trasformazione in corso infatti, stravolgerà sia i consolidati modelli di gestione operativa e di dispacciamento, sia le dinamiche dei mercati elettrici portando ad essere le comunità energetiche un’occasione che non può essere sprecata. Data l’ampiezza della ricerca a tutti i livelli, molteplici sono stati i risultati: - Il quadro della situazione rinnovabili nel contesto globale, Europeo e nazionale ha permesso di capire quali saranno gli scenari futuri è ciò rappresenta un importante risultato per indirizzare le scelte sul sistema elettrico; - Lo studio dei prezzi dell’energia elettrica e delle tariffe per utenti finali ha permesso di dare una dimensione ai benefici e alle possibilità che si riescono ad ottenere per gli utenti finali domestici residenziali con autoconsumo da FER; - Il modello generale proposto con la definizione degli attori coinvolti permette di trarre informazioni utili o replicare quale sono i passi necessari per la realizzazione di impianti in ‘grid parity’ sia di piccola che di grande taglia e come definire la durata dei possibili contratti di vendita dell’energia (PPA e SEU); - L’applicazione nella simulazione, di concetti sviluppati in laboratorio dal gruppo di ricerca di Sistemi Elettrici per l’Energia permette di dare una prima analisi di fattibilità dell’iniziativa e degli investimenti per un eventuale opportunità di business che si aprirebbe dalle comunità energetiche con scambio virtuale; - La descrizione degli elementi e di un modello di business a supporto dello sviluppo di comunità energetiche; - Primi risultati economico-finanziari di una comunità energetica applicata al caso Italiano con la numerosità utile del campione per la sostenibilità. Il contributo scientifico apportato al panorama nazionale, europeo e internazionale si è concretizzato con la pubblicazione di una serie di articoli scientifici che hanno evidenziato, in ambito nazionale il vantaggio nell’aggregazione di impianti rinnovabili non programmabili secondo le attuali e previste politiche di gestione degli sbilanciamenti; la differenze di gestione di impianti tra ambito nazionale ed altri paesi europei con una simile incidenza di fonti rinnovabili (ad esempio la Spagna); gli effetti dell’autoconsumo relativo ai Prosumers sia in ambito nazionale che internazionale. Per quanto riguarda gli investimenti in grandi impianti di generazione per servire direttamente utenti consumatori di energia, attraverso la soluzione dei Power PurchaseAgreement (PPA) si è fornita una dettagliata descrizione degli attori coinvolti nel modello e dei costi e ricavi per costruire un opportuno LCOE e realizzare impianti in grid parity, siano essi fotovoltaici o eolici. Sulla gestione degli utenti attivi in forma di comunità energetiche invece il modello di business proposto che dà un ruolo centrale alle fonti rinnovabili in forma aggregata e gestite da un unico soggetto, restituisce informazioni utili a investitori e/o produttori. Il lavoro propone e analizza possibili modelli di mercato che permettono di affrontare efficacemente i cambiamenti dei prossimi anni ed è stato strutturato come di seguito: - Nel primo si evidenziano gli impatti causati dalle fonti rinnovabili non programmabili nel sistema elettrico; - Nel secondo capitolo si descrivono, le comunità energetiche come possibile soluzione di mercato per favorire l’integrazione della generazione rinnovabile-distribuita nelle reti elettriche insieme al ruolo degli Aggregatori. - Nel terzo capitolo si presentano alcuni modelli di business per la gestione di comunità energetiche facendo una proposta nel caso di utenti finali domestici che dispongono di impianti di generazione fotovoltaica di piccola taglia; - Nel corso dell’ultimo capitolo si mostrano i risultati di alcune simulazioni numeriche condotte su una configurazione di comunità energetica gestita da soggetto terzo Aggregatore.Item Analysis of mechanical properties of cold spray coatings for tribological and vacuum applications(Università della Calabria, 2020-07-13) Magarò, Pietro; Furgiuele, Franco; Maletta, Carmine; Tului, MarioCold Gas Dynamic Spray (CGDS) is a process in which solid particle are accelerated in a de Laval nozzle toward a substrate. At the impact, if the particle velocity exceeds a critical value, i.e. the critical velocity, particles undergo plastic deformation and the consequent adiabatic shear instability provides material flow and heat for bonding. This phenomenon is the main driving force for the adhesion of the coating to the substrate. Compared other thermal spray techniques, since it utilizes kinetic rather than thermal energy for deposition, it offers several technological advantages; in fact, residual stresses, oxidation and chemical reactions can be avoided. Materials such as metals, ceramics, composites and polymers can be deposited using cold gas dynamic spray, creating new opportunities in order to obtain particular properties; in fact, good coatings using hard metals can be obtained with the purpose to enhance the tribological properties of such mechanical components. Therefore, the expected qualitative leap in using CGDS is magnified in harsh environments with great benefits predicted in design flexibility gains, precision improvements, production time reductions, cost reduction, integration of additional embedded functionalities. The purpose of this thesis is to demonstrate the possibility to obtain good deposits of Stellite-6 with the aim to enhance the surface resistance during sliding condition, while mechanical and vacuum properties of pure titanium coatings were analyzed for possible application in ultra high vacuum (UHV) systems at the European Organization for Nuclear Research (CERN). This thesis, firstly, analyzes the effects of process parameters on mechanical and tribological properties of Stellite-6 coatings. The gas pressure and temperature as well as the traverse speed of the deposition torch were considered as significant process parameters. The aim is to overcome some technical issues arising in the cold spray deposition of hard anti-wear metallic coatings, such as Stellite-6, due to their high strength and melting point. A High-Pressure CGDS equipment was used and systematic studies were carried out for a deeper understanding of the effects of all investigated process parameters. A particular focus has been put on the substrate temperature, that can be regarded as an indirect process parameter. This latter, in fact, was monitored in-situ during deposition by infrared thermography (𝐼𝐼𝐼𝐼). The microstructure was analyzed by both optical and scanning electron microscopic observations. Mechanical properties were analyzed by instrumented micro- and nano-indentation measurements. Hardness (𝐻𝐻) and Young's modulus (𝐸𝐸) were considered as affective parameters to estimate the inter-particle cohesion strength and the work hardening of the coating. Results revealed that the substrate temperature, that is affected by the process parameters, plays a fundamental role in the coating formation process, and, both mechanical and tribological properties, of CGDS Stellite-6 coatings are mainly affected by the impact temperature of the particle-substrate system. It is also well-known that this alloy undergoes several physical changes at the interface during dry sliding while is sensitive to the loading conditions and environment. Due to these micro-structural alterations, the wear behavior of the alloy is modified, which linear Archard-like wear models could not capture. To better understand the wear performance a Stellite-6 coatings in-situ, a mechanistic model of wear would be desirable, so a systematic experimental study was performed. Tests were done under combinations of sliding speed (0.1–0.5 𝑚𝑚/𝑠𝑠) and contact pressure (0,5–5 𝑀𝑀𝑀𝑀𝑀𝑀). Platelet wear and subsurface cracking was seen in high speed tests, as well as evidence of plastic deformation at the wear surface. These results suggest the platelet wear observed is more likely a consequence of adhesive wear. On the other hand, in low speed conditions detachment and pull-out phenomena mainly affect the worn surface of coatings leading to a type of fatigue wear known as “nano-grain wear” that does not allow to use the wear model proposed by Archard. Unique to this study, the cross-sectional nano-indentation study showed the stiffness of material at and below wear interface to drop significantly. The last section was aimed by the necessity to overcome some technical issues, usually experienced during pure titanium deposition. These latter are mainly related to poor coating compactness and adhesion to the substrates. These technical issues become even more stringent when dealing with vacuum systems as they could affect the leak tightness and gas release in UHV. Preliminary micrographic observations were carried out to select the optimal values of the process parameters, that are pressure (𝑝𝑝) and temperature (𝑇𝑇) of the propellent gas. Mechanical properties of deposits were subsequently analyzed at the nano/micro and macro scale by instrumented indentations and adhesion tensile tests respectively. Vacuum properties were analyzed by outgassing rate measurements, thermal desorption spectroscopy (TDS) and helium tightness tests. Indentation results revealed that compact and homogeneous coatings can be obtained if high energy deposition parameters (𝑝𝑝~4 𝑀𝑀𝑀𝑀𝑀𝑀,𝑇𝑇~1000° 𝐶𝐶) are applied. However, a limited adhesion strength on stainless steel substrates is the main technical issue of the coating process. Outgassing and TDS tests revealed an abnormal nitrogen release that is attributed to gas entrapped during deposition or during the production stage of the Ti powders as N2 is used in the gas atomization process. Finally, helium leak rates were found to be incompatible with UHV requirements applied in modern particle accelerators. Much higher helium leak rates were detected along the interface between the coating and the substrate than through the thickness. These results confirm that the interface represents the weakest point of the bi-material system. Further studies are needed to solve this technical issue.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 Modellazione Numerica per l’ottimizzazione multi-obiettivo di sistemi in assetto co- e tri-generativo(Università della Calabria, 2022-07-08) Lucarelli, Giuseppe; Conte, Enrico; Fragiacomo, PetronillaItem Studio delle tecnologie di localizzazione acustica subacquea e sviluppo di tecniche per la riduzione dell'errore di posizione(Università della Calabria, 2023-02-08) Aiello, Rosario; Conte, Enrico; Bruno, FabioItem The Role of Physics Based Modeling of Macro/Micro Machining Operations in the Era of Electric Vehicles Revolution(Università della Calabria, 2021-05-28) Rinaldi, Sergio; Conte, Enrico; Umbrello, DomenicoItem Quantitative approaches for the integrated management of agri-food supply chains(Università della Calabria, 2021-06-10) Solina, Vittorio; Conte, Enrico; Mirabelli, GiovanniIn recent years, the development of global markets and higher expectations from end customers have forced the supply chain players to better coordinate and integrate their plans, in order to maintain high levels of performance and be competitive on the market. Today, in fact, companies compete not only on product price or quality, but also on the reliability and timeliness of deliveries. Managing a supply chain in an integrated and coordinated manner is even more complicated and challenging, with reference to the agri-food context, where the constraints about quality and safety of goods, that are usually perishable, are much more stringent than in other sectors. By coordinating the various activities, it is possible to make supply chains more efficient and sustainable, as products can be made and distributed in the right quantity, at the right time and to the right customer. In support of integrated planning, new technologies are recently spreading, with the aim of making the sharing of data and information between the various actors safe and efficient. In this regard, the blockchain is among those technologies, whose interest has grown the most in recent months, both from the academic and business world. The present dissertation mainly aims to develop, test and validate novel quantitative approaches for the integrated management of agri-food chains. • In Chapter 2, a review of the main scientific works published in the last 15 years is proposed, referring to the integration of production, storage and distribution activities, via optimization strategies, within perishable supply chains. In this context, in order to identify effectively the different research gaps and to suggest possible future challenges, a five-dimension classification framework is proposed. This review is the starting point for the following 3 chapters, which address as many case studies. • In Chapter 3, an optimization model is designed for the simultaneous management of the storage and distribution of agricultural products. It is used to maximize the profits of a real company, which deals with the planting, growing, harvesting, storage and distribution of cauliflowers to a main customer and to spot customers. A hybrid fresh-/old-first inventory management policy is modeled to balance the quality of the delivered product and limit the amount wasted. The model improves the current practices of the firm and supports effectively the day-to-day decisionmaking regarding the quantities of product, for each age, to be stored and distributed to each customer. • In Chapter 4, a model is instead developed and tested to integrate the activities of production (i.e., harvesting), storage, distribution and routing of perishable agri-products. The case study refers to two companies, located in Southern Italy. At the tactical level, the proposed model determines the optimal value of two important operating parameters: the frequency of the harvesting activities and the service level to be guaranteed to customers. At the operational level, instead, the model is a valid tool to suggest to the company, day-to-day, the optimal quantities to harvest, store, distribute, and the routes to travel to reach customers, in order to maximize profits and contain waste. In this context, considering that the companies of the case study share some customers and are not in competition, as they are heterogeneous in terms of marketed products, the possibility of horizontal collaboration is also explored. The collaboration, as intended in this Chapter, implies that one of the two actors makes its own fleet of vehicles available, in exchange for a fee. In this context, a heuristic framework is proposed and validated. It suggests collaborating day by day, only if collaboration is economically convenient for both the companies. Computational tests, carried out on randomly generated instances, reveal that the collaboration can guarantee significant savings in terms of CO2 emissions and therefore make the supply chain more sustainable. • Chapter 5 deals with the integration of the production, storage and distribution activities of a company in the vegetable sector. In the production field, a scheduling problem is solved, which takes into account the set-up times of the production line, the hourly fluctuations in the energy price and the perishable nature of raw materials. In the distribution field, instead, it is necessary to schedule deliveries in terms of quantity of shipped products and days. The proposed model allows to schedule both production and distribution in an integrated way. Two rescheduling strategies are tested, to adequately react to customer demand, which occurs on a weekly basis. The first reproduces the current behavior of the company, while the second allows to improve current practices and jointly minimize the costs of energy, storage and distribution. • In Chapter 6, considering the recent proliferation of scientific works on the theoretical or practical use of blockchain technology in the agri-food sector, a literature review on this topic is proposed. This tool, since it allows the real-time sharing of information between the various players in the supply chain in a safe and efficient way, can facilitate the coordination of production and distribution plans, which is the main subject of the previous chapters of this thesis work. The aim is to identify current research trends and inform the reader about the degree