City logistics: trasporto merci in ambito urbano

Molteplici studi, portati a termine di recente in Europa ed oltreoceano, hanno focalizzato l’attenzione sulle problematiche indotte dal trasporto merci in ambito urbano e contribuito ad identificarne possibili soluzioni (city logistics). Le aree urbane, dovrebbero idealmente essere luoghi ove abitare, svolgere attività economiche, sociali e ricreative. Esse possono vedere compromessa la loro predisposizione a tali scopi anche a causa del crescente traffico delle merci, il cui trasporto è effettuato principalmente su gomma, per via delle brevi distanze da coprire e delle carenze infrastrutturali. I veicoli commerciali, ad eccezione di quelli di ultima generazione, incidono negativamente sulla qualità dell’ambiente urbano, generando inquinamento atmosferico e acustico. La politica del “just in time”, che prevede l’assenza di magazzini di stoccaggio delle merci, incrementa i movimenti commerciali. Nella presente tesi vengono trattati alcuni aspetti logistici di regolamentazione della sosta e degli accessi per i mezzi di trasporto merci, in grado di rendere più efficiente la distribuzione dei beni, mitigando le problematiche indotte dal traffico e, quindi, salvaguardando la qualità di vita nei centri cittadini.

Dynamic identification of structures: experimental assessment of modal parameteres through methods in frequency domain, in time-frequency domain and model updating

Among the experimental methods commonly used to define the behaviour of a full scale system, dynamic tests are the most complete and efficient procedures. A dynamic test is an experimental process, which would define a set of characteristic parameters of the dynamic behaviour of the system, such as natural frequencies of the structure, mode shapes and the corresponding modal damping values associated. An assessment of these modal characteristics can be used both to verify the theoretical assumptions of the project, to monitor the performance of the structural system during its operational use. The thesis is structured in the following chapters: The first introductive chapter recalls some basic notions of dynamics of structure, focusing the discussion on the problem of systems with multiply degrees of freedom (MDOF), which can represent a generic real system under study, when it is excited with harmonic force or in free vibration. The second chapter is entirely centred on to the problem of dynamic identification process of a structure, if it is subjected to an experimental test in forced vibrations. It first describes the construction of FRF through classical FFT of the recorded signal. A different method, also in the frequency domain, is subsequently introduced; it allows accurately to compute the FRF using the geometric characteristics of the ellipse that represents the direct input-output comparison. The two methods are compared and then the attention is focused on some advantages of the proposed methodology. The third chapter focuses on the study of real structures when they are subjected to experimental test, where the force is not known, like in an ambient or impact test. In this analysis we decided to use the CWT, which allows a simultaneous investigation in the time and frequency domain of a generic signal x(t). The CWT is first introduced to process free oscillations, with excellent results both in terms of frequencies, dampings and vibration modes. The application in the case of ambient vibrations defines accurate modal parameters of the system, although on the damping some important observations should be made. The fourth chapter is still on the problem of post processing data acquired after a vibration test, but this time through the application of discrete wavelet transform (DWT). In the first part the results obtained by the DWT are compared with those obtained by the application of CWT. Particular attention is given to the use of DWT as a tool for filtering the recorded signal, in fact in case of ambient vibrations the signals are often affected by the presence of a significant level of noise. The fifth chapter focuses on another important aspect of the identification process: the model updating. In this chapter, starting from the modal parameters obtained from some environmental vibration tests, performed by the University of Porto in 2008 and the University of Sheffild on the Humber Bridge in England, a FE model of the bridge is defined, in order to define what type of model is able to capture more accurately the real dynamic behaviour of the bridge. The sixth chapter outlines the necessary conclusions of the presented research. They concern the application of a method in the frequency domain in order to evaluate the modal parameters of a structure and its advantages, the advantages in applying a procedure based on the use of wavelet transforms in the process of identification in tests with unknown input and finally the problem of 3D modeling of systems with many degrees of freedom and with different types of uncertainty.

Teoria e applicazioni sul tema della logistica urbana

Il tema della Logistica Urbana è un argomento complesso che coinvolge diverse discipline. Infatti, non è possibile affrontare la distribuzione delle merci da un solo punto di vista. Da un lato, infatti, manifesta l’esigenza della città e della società in generale di migliorare la qualità della vita anche attraverso azioni di contenimento del traffico, dell’inquinamento e degli sprechi energetici. A questo riguardo, è utile ricordare che il trasporto merci su gomma costituisce uno dei maggiori fattori di impatto su ambiente, sicurezza stradale e congestione della viabilità urbana. Dall’altro lato vi sono le esigenze di sviluppo economico e di crescita del territorio dalle quali non è possibile prescindere. In questa chiave, le applicazioni inerenti la logistica urbana si rivolgono alla ricerca di soluzioni bilanciate che possano arrecare benefici sociali ed economici al territorio anche attraverso progetti concertati tra i diversi attori coinvolti. Alla base di tali proposte di pratiche e progetti, si pone il concetto di esternalità inteso come l’insieme dei costi esterni sostenuti dalla società imputabili al trasporto, in particolare al trasporto merci su gomma. La valutazione di questi costi, che rappresentano spesso una misurazione qualitativa, è un argomento delicato in quanto, come è facile immaginare, non può essere frutto di misure dirette, ma deve essere dedotto attraverso meccanismi inferenziali. Tuttavia una corretta definizione delle esternalità definisce un importante punto di partenza per qualsiasi approccio al problema della Logistica Urbana. Tra gli altri fattori determinanti che sono stati esplorati con maggiore dettaglio nel testo integrale della tesi, va qui accennata l’importanza assunta dal cosiddetto Supply Chain Management nell’attuale assetto organizzativo industriale. Da esso dipendono approvvigionamenti di materie prime e consegne dei prodotti finiti, ma non solo. Il sistema stesso della distribuzione fa oggi parte di quei servizi che si integrano con la qualità del prodotto e dell’immagine della Azienda. L’importanza di questo settore è accentuata dal fatto che le evoluzioni del commercio e l’appiattimento dei differenziali tra i sistemi di produzione hanno portato agli estremi la competizione. In questa ottica, minimi vantaggi in termini di servizio e di qualità si traducono in enormi vantaggi in termini di competitività e di acquisizione di mercato. A questo si aggiunge una nuova logica di taglio dei costi che porta a ridurre le giacenze di magazzino accorciando la pipeline di produzione ai minimi termini in tutte le fasi di filiera. Naturalmente questo si traduce, al punto vendita in una quasi totale assenza di magazzino. Tecnicamente, il nuovo modello di approvvigionamento viene chiamato just-in-time. La ricerca che è stata sviluppata in questi tre anni di Dottorato, sotto la supervisione del Prof. Piero Secondini, ha portato ad un approfondimento di questi aspetti in una chiave di lettura ad ampio spettro. La ricerca si è quindi articolata in 5 fasi: 1. Ricognizione della letteratura italiana e straniera in materia di logistica e di logistica urbana; 2. Studio delle pratiche nazionali ed europee 3. Analisi delle esperienze realizzate e delle problematiche operative legate ai progetti sostenuti dalla Regione Emilia Romagna 4. Il caso di studio di Reggio Emilia e redazione di più proposte progettuali 5. Valutazione dei risultati e conclusioni Come prima cosa si è quindi studiata la letteratura in materia di Logistica Urbana a livello nazionale. Data la relativamente recente datazione dei primi approcci nazionali ed europei al problema, non erano presenti molti testi in lingua italiana. Per contro, la letteratura straniera si riferisce generalmente a sistemi urbani di dimensione e configurazione non confrontabili con le realtà nazionali. Ad esempio, una delle nazioni che hanno affrontato per prime tale tematica e sviluppato un certo numero di soluzioni è stata il Giappone. Naturalmente, città come Tokyo e Kyoto sono notevolmente diverse dalle città europee ed hanno necessità ed esigenze assai diverse. Pertanto, soluzioni tecnologiche e organizzative applicate in questi contesti sono per la maggior parte inattuabili nei contesti del vecchio continente. Le fonti che hanno costituito maggiore riferimento per lo sviluppo del costrutto teorico della tesi, quindi, sono state i saggi che la Regione Emilia Romagna ha prodotto in occasione dello sviluppo del progetto City Ports di cui la Regione stessa era coordinatore di numerosi partners nazionali ed europei. In ragione di questo progetto di ricerca internazionale, l’Emilia Romagna ha incluso il trattamento della logistica delle merci negli “Accordi di Programma per il miglioramento della qualità dell’aria” con le province ed i capoluoghi. In Questo modo si è posta l’attenzione sulla sensibilizzazione delle Pubbliche Amministrazioni locali verso la mobilità sostenibile anche nell’ambito di distribuzione urbana delle merci. Si noti infatti che l’impatto sulle esternalità dei veicoli leggeri per il trasporto merci, quelli cioè che si occupano del cosiddetto “ultimo miglio” sono di due ordini di grandezza superiori rispetto a quelli dei veicoli passeggeri. Nella seconda fase, la partecipazione a convegni di ambito regionale e nazionale ha permesso di arricchire le conoscenze delle best-practice attuate in Italia per lo sviluppo di strumenti finalizzati ad condividere i costi esterni della mobilità delle merci con gli operatori logistici. In questi contesti è stato possibile verificare la disponibilità di tre linee di azione sulle quali, all’interno del testo della tesi si farà riferimento molto spesso: - linea tecnologica; - linea amministrativa; - linea economico/finanziaria. Nel discutere di questa tematica, all’interno di questi contesti misti in cui partecipavano esponenti della cultura accademica, delle pubbliche amministrazioni e degli operatori, ci si è potuti confrontare con la complessità che il tema assume. La terza fase ha costituito la preparazione fondamentale allo studio del caso di studio. Come detto sopra, la Regione Emilia Romagna, all’interno degli Accordi di Programma con le Province, ha deliberato lo stanziamento di co-finanziamenti per lo sviluppo di progetti, integrati con le pratiche della mobilità, inerenti la distribuzione delle merci in città. Inizialmente, per tutti i capoluoghi di provincia, la misura 5.2 degli A.d.P. prevedeva la costruzione di un Centro di Distribuzione Urbana e l’individuazione di un gestore dei servizi resi dallo stesso. Successive considerazioni hanno poi portato a modifiche della misura lasciando una maggiore elasticità alle amministrazioni locali. Tramite una esperienza di ricerca parallela e compatibile con quella del Dottorato finanziata da un assegno di ricerca sostenuto dall’Azienda Consorziale Trasporti di Reggio Emilia, si è potuto partecipare a riunioni e seminari presentati dalla Regione Emilia Romagna in cui si è potuto prendere conoscenza delle proposte progettuali di tutte le province. L’esperienza di Reggio Emilia costituisce il caso di studio della tesi di Dottorato. Le molteplici problematiche che si sono affrontate si sono protratte per tempi lunghi che hanno visto anche modifiche consistenti nell’assetto della giunta e del consiglio comunali. Il fatto ha evidenziato l’ennesimo aspetto problematico legato al mantenimento del patrimonio conoscitivo acquisito, delle metodiche adottate e di mantenimento della coerenza dell’impostazione – in termini di finalità ed obiettivi – da parte dell’Amministrazione Pubblica. Essendo numerosi gli attori coinvolti, in un progetto di logistica urbana è determinante per la realizzazione e la riuscita del progetto che ogni fattore sia allineato e ben informato dell’evoluzione del progetto. In termini di programmazione economica e di pianificazione degli interventi, inoltre, la pubblica amministrazione deve essere estremamente coordinata internamente. Naturalmente, questi sono fattori determinanti per ogni progetto che riguarda le trasformazioni urbane e lo sviluppo delle città. In particolare, i diversi settori (assessorati) coinvolti su questa tematica, fanno o possno fare entrare in situazioni critiche e rischiose la solidità politica dello schieramento di maggioranza. Basti pensare che la distribuzione delle merci in città coinvolge gli assessorati della mobilità, del commercio, del centro storico, dell’ambiente, delle attività produttive. In funzione poi delle filiere che si ritiene di coinvolgere, anche la salute e la sicurezza posso partecipare al tavolo in quanto coinvolte rispettivamente nella distribuzione delle categorie merceologiche dei farmaci e nella security dei valori e della safety dei trasporti. L’esperienza di Reggio Emilia è stata una opportunità preziosissima da molteplici punti di vista. Innanzitutto ha dato modo di affrontare in termini pratici il problema, di constatare le difficoltà obiettive, ad esempio nella concertazione tra gli attori coinvolti, di verificare gli aspetti convergenti su questo tema. Non ultimo in termini di importanza, la relazione tra la sostenibilità economica del progetto in relazione alle esigenze degli operatori commerciali e produttivi che ne configurano gli spazi di azione. Le conclusioni del lavoro sono molteplici. Da quelle già accennate relative alla individuazione delle criticità e dei rischi a quelle dei punti di forza delle diverse soluzioni. Si sono affrontate, all’interno del testo, le problematiche più evidenti cercando di darne una lettura costruttiva. Si sono evidenziate anche le situazioni da evitare nel percorso di concertazione e si è proposto, in tal proposito, un assetto organizzativo efficiente. Si è presentato inoltre un modello di costruzione del progetto sulla base anche di una valutazione economica dei risultati per quanto riguarda il Business Plan del gestore in rapporto con gli investimenti della P.A.. Si sono descritti diversi modelli di ordinanza comunale per la regolamentazione della circolazione dei mezzi leggeri per la distribuzione delle merci in centro storico con una valutazione comparativa di meriti ed impatti negativi delle stesse. Sono inoltre state valutate alcune combinazioni di rapporto tra il risparmio in termini di costi esterni ed i possibili interventi economico finanziario. Infine si è analizzato il metodo City Ports evidenziando punti di forza e di debolezza emersi nelle esperienze applicative studiate.

Monitoring Complex Processes to Verify System Conformance: A Declarative Rule-Based Framework

Over the last 60 years, computers and software have favoured incredible advancements in every field. Nowadays, however, these systems are so complicated that it is difficult – if not challenging – to understand whether they meet some requirement or are able to show some desired behaviour or property. This dissertation introduces a Just-In-Time (JIT) a posteriori approach to perform the conformance check to identify any deviation from the desired behaviour as soon as possible, and possibly apply some corrections. The declarative framework that implements our approach – entirely developed on the promising open source forward-chaining Production Rule System (PRS) named Drools – consists of three components: 1. a monitoring module based on a novel, efficient implementation of Event Calculus (EC), 2. a general purpose hybrid reasoning module (the first of its genre) merging temporal, semantic, fuzzy and rule-based reasoning, 3. a logic formalism based on the concept of expectations introducing Event-Condition-Expectation rules (ECE-rules) to assess the global conformance of a system. The framework is also accompanied by an optional module that provides Probabilistic Inductive Logic Programming (PILP). By shifting the conformance check from after execution to just in time, this approach combines the advantages of many a posteriori and a priori methods proposed in literature. Quite remarkably, if the corrective actions are explicitly given, the reactive nature of this methodology allows to reconcile any deviations from the desired behaviour as soon as it is detected. In conclusion, the proposed methodology brings some advancements to solve the problem of the conformance checking, helping to fill the gap between humans and the increasingly complex technology.

Non-Markovian stochastic processes and their applications: from anomalous diffusion to time series analysis

This work provides a forward step in the study and comprehension of the relationships between stochastic processes and a certain class of integral-partial differential equation, which can be used in order to model anomalous diffusion and transport in statistical physics. In the first part, we brought the reader through the fundamental notions of probability and stochastic processes, stochastic integration and stochastic differential equations as well. In particular, within the study of H-sssi processes, we focused on fractional Brownian motion (fBm) and its discrete-time increment process, the fractional Gaussian noise (fGn), which provide examples of non-Markovian Gaussian processes. The fGn, together with stationary FARIMA processes, is widely used in the modeling and estimation of long-memory, or long-range dependence (LRD). Time series manifesting long-range dependence, are often observed in nature especially in physics, meteorology, climatology, but also in hydrology, geophysics, economy and many others. We deepely studied LRD, giving many real data examples, providing statistical analysis and introducing parametric methods of estimation. Then, we introduced the theory of fractional integrals and derivatives, which indeed turns out to be very appropriate for studying and modeling systems with long-memory properties. After having introduced the basics concepts, we provided many examples and applications. For instance, we investigated the relaxation equation with distributed order time-fractional derivatives, which describes models characterized by a strong memory component and can be used to model relaxation in complex systems, which deviates from the classical exponential Debye pattern. Then, we focused in the study of generalizations of the standard diffusion equation, by passing through the preliminary study of the fractional forward drift equation. Such generalizations have been obtained by using fractional integrals and derivatives of distributed orders. In order to find a connection between the anomalous diffusion described by these equations and the long-range dependence, we introduced and studied the generalized grey Brownian motion (ggBm), which is actually a parametric class of H-sssi processes, which have indeed marginal probability density function evolving in time according to a partial integro-differential equation of fractional type. The ggBm is of course Non-Markovian. All around the work, we have remarked many times that, starting from a master equation of a probability density function f(x,t), it is always possible to define an equivalence class of stochastic processes with the same marginal density function f(x,t). All these processes provide suitable stochastic models for the starting equation. Studying the ggBm, we just focused on a subclass made up of processes with stationary increments. The ggBm has been defined canonically in the so called grey noise space. However, we have been able to provide a characterization notwithstanding the underline probability space. We also pointed out that that the generalized grey Brownian motion is a direct generalization of a Gaussian process and in particular it generalizes Brownain motion and fractional Brownain motion as well. Finally, we introduced and analyzed a more general class of diffusion type equations related to certain non-Markovian stochastic processes. We started from the forward drift equation, which have been made non-local in time by the introduction of a suitable chosen memory kernel K(t). The resulting non-Markovian equation has been interpreted in a natural way as the evolution equation of the marginal density function of a random time process l(t). We then consider the subordinated process Y(t)=X(l(t)) where X(t) is a Markovian diffusion. The corresponding time-evolution of the marginal density function of Y(t) is governed by a non-Markovian Fokker-Planck equation which involves the same memory kernel K(t). We developed several applications and derived the exact solutions. Moreover, we considered different stochastic models for the given equations, providing path simulations.

Numerical simulations of magma chamber dynamics at Campi Flegrei, and associated seismicity, deformation and gravity changes

Understanding the complex relationships between quantities measured by volcanic monitoring network and shallow magma processes is a crucial headway for the comprehension of volcanic processes and a more realistic evaluation of the associated hazard. This question is very relevant at Campi Flegrei, a volcanic quiescent caldera immediately north-west of Napoli (Italy). The system activity shows a high fumarole release and periodic ground slow movement (bradyseism) with high seismicity. This activity, with the high people density and the presence of military and industrial buildings, makes Campi Flegrei one of the areas with higher volcanic hazard in the world. In such a context my thesis has been focused on magma dynamics due to the refilling of shallow magma chambers, and on the geophysical signals detectable by seismic, deformative and gravimetric monitoring networks that are associated with this phenomenologies. Indeed, the refilling of magma chambers is a process frequently occurring just before a volcanic eruption; therefore, the faculty of identifying this dynamics by means of recorded signal analysis is important to evaluate the short term volcanic hazard. The space-time evolution of dynamics due to injection of new magma in the magma chamber has been studied performing numerical simulations with, and implementing additional features in, the code GALES (Longo et al., 2006), recently developed and still on the upgrade at the Istituto Nazionale di Geofisica e Vulcanologia in Pisa (Italy). GALES is a finite element code based on a physico-mathematical two dimensional, transient model able to treat fluids as multiphase homogeneous mixtures, compressible to incompressible. The fundamental equations of mass, momentum and energy balance are discretised both in time and space using the Galerkin Least-Squares and discontinuity-capturing stabilisation technique. The physical properties of the mixture are computed as a function of local conditions of magma composition, pressure and temperature.The model features enable to study a broad range of phenomenologies characterizing pre and sin-eruptive magma dynamics in a wide domain from the volcanic crater to deep magma feeding zones. The study of displacement field associated with the simulated fluid dynamics has been carried out with a numerical code developed by the Geophysical group at the University College Dublin (O’Brien and Bean, 2004b), with whom we started a very profitable collaboration. In this code, the seismic wave propagation in heterogeneous media with free surface (e.g. the Earth’s surface) is simulated using a discrete elastic lattice where particle interactions are controlled by the Hooke’s law. This method allows to consider medium heterogeneities and complex topography. The initial and boundary conditions for the simulations have been defined within a coordinate project (INGV-DPC 2004-06 V3_2 “Research on active volcanoes, precursors, scenarios, hazard and risk - Campi Flegrei”), to which this thesis contributes, and many researchers experienced on Campi Flegrei in volcanological, seismic, petrological, geochemical fields, etc. collaborate. Numerical simulations of magma and rock dynamis have been coupled as described in the thesis. The first part of the thesis consists of a parametric study aimed at understanding the eect of the presence in magma of carbon dioxide in magma in the convection dynamics. Indeed, the presence of this volatile was relevant in many Campi Flegrei eruptions, including some eruptions commonly considered as reference for a future activity of this volcano. A set of simulations considering an elliptical magma chamber, compositionally uniform, refilled from below by a magma with volatile content equal or dierent from that of the resident magma has been performed. To do this, a multicomponent non-ideal magma saturation model (Papale et al., 2006) that considers the simultaneous presence of CO2 and H2O, has been implemented in GALES. Results show that the presence of CO2 in the incoming magma increases its buoyancy force promoting convection ad mixing. The simulated dynamics produce pressure transients with frequency and amplitude in the sensitivity range of modern geophysical monitoring networks such as the one installed at Campi Flegrei . In the second part, simulations more related with the Campi Flegrei volcanic system have been performed. The simulated system has been defined on the basis of conditions consistent with the bulk of knowledge of Campi Flegrei and in particular of the Agnano-Monte Spina eruption (4100 B.P.), commonly considered as reference for a future high intensity eruption in this area. The magmatic system has been modelled as a long dyke refilling a small shallow magma chamber; magmas with trachytic and phonolitic composition and variable volatile content of H2O and CO2 have been considered. The simulations have been carried out changing the condition of magma injection, the system configuration (magma chamber geometry, dyke size) and the resident and refilling magma composition and volatile content, in order to study the influence of these factors on the simulated dynamics. Simulation results allow to follow each step of the gas-rich magma ascent in the denser magma, highlighting the details of magma convection and mixing. In particular, the presence of more CO2 in the deep magma results in more ecient and faster dynamics. Through this simulations the variation of the gravimetric field has been determined. Afterward, the space-time distribution of stress resulting from numerical simulations have been used as boundary conditions for the simulations of the displacement field imposed by the magmatic dynamics on rocks. The properties of the simulated domain (rock density, P and S wave velocities) have been based on data from literature on active and passive tomographic experiments, obtained through a collaboration with A. Zollo at the Dept. of Physics of the Federici II Univeristy in Napoli. The elasto-dynamics simulations allow to determine the variations of the space-time distribution of deformation and the seismic signal associated with the studied magmatic dynamics. In particular, results show that these dynamics induce deformations similar to those measured at Campi Flegrei and seismic signals with energies concentrated on the typical frequency bands observed in volcanic areas. The present work shows that an approach based on the solution of equations describing the physics of processes within a magmatic fluid and the surrounding rock system is able to recognise and describe the relationships between geophysical signals detectable on the surface and deep magma dynamics. Therefore, the results suggest that the combined study of geophysical data and informations from numerical simulations can allow in a near future a more ecient evaluation of the short term volcanic hazard.

Characterization and modeling of low-frequency noise in MOSFETs

For many years, RF and analog integrated circuits have been mainly developed using bipolar and compound semiconductor technologies due to their better performance. In the last years, the advance made in CMOS technology allowed analog and RF circuits to be built with such a technology, but the use of CMOS technology in RF application instead of bipolar technology has brought more issues in terms of noise. The noise cannot be completely eliminated and will therefore ultimately limit the accuracy of measurements and set a lower limit on how small signals can be detected and processed in an electronic circuit. One kind of noise which affects MOS transistors much more than bipolar ones is the low-frequency noise. In MOSFETs, low-frequency noise is mainly of two kinds: flicker or 1/f noise and random telegraph signal noise (RTS). The objective of this thesis is to characterize and to model the low-frequency noise by studying RTS and flicker noise under both constant and switched bias conditions. The effect of different biasing schemes on both RTS and flicker noise in time and frequency domain has been investigated.

Magnetohydrodynamic Effects On Mixed Convection Flows In Channels And Ducts

This work focuses on magnetohydrodynamic (MHD) mixed convection flow of electrically conducting fluids enclosed in simple 1D and 2D geometries in steady periodic regime. In particular, in Chapter one a short overview is given about the history of MHD, with reference to papers available in literature, and a listing of some of its most common technological applications, whereas Chapter two deals with the analytical formulation of the MHD problem, starting from the fluid dynamic and energy equations and adding the effects of an external imposed magnetic field using the Ohm's law and the definition of the Lorentz force. Moreover a description of the various kinds of boundary conditions is given, with particular emphasis given to their practical realization. Chapter three, four and five describe the solution procedure of mixed convective flows with MHD effects. In all cases a uniform parallel magnetic field is supposed to be present in the whole fluid domain transverse with respect to the velocity field. The steady-periodic regime will be analyzed, where the periodicity is induced by wall temperature boundary conditions, which vary in time with a sinusoidal law. Local balance equations of momentum, energy and charge will be solved analytically and numerically using as parameters either geometrical ratios or material properties. In particular, in Chapter three the solution method for the mixed convective flow in a 1D vertical parallel channel with MHD effects is illustrated. The influence of a transverse magnetic field will be studied in the steady periodic regime induced by an oscillating wall temperature. Analytical and numerical solutions will be provided in terms of velocity and temperature profiles, wall friction factors and average heat fluxes for several values of the governing parameters. In Chapter four the 2D problem of the mixed convective flow in a vertical round pipe with MHD effects is analyzed. Again, a transverse magnetic field influences the steady periodic regime induced by the oscillating wall temperature of the wall. A numerical solution is presented, obtained using a finite element approach, and as a result velocity and temperature profiles, wall friction factors and average heat fluxes are derived for several values of the Hartmann and Prandtl numbers. In Chapter five the 2D problem of the mixed convective flow in a vertical rectangular duct with MHD effects is discussed. As seen in the previous chapters, a transverse magnetic field influences the steady periodic regime induced by the oscillating wall temperature of the four walls. The numerical solution obtained using a finite element approach is presented, and a collection of results, including velocity and temperature profiles, wall friction factors and average heat fluxes, is provided for several values of, among other parameters, the duct aspect ratio. A comparison with analytical solutions is also provided, as a proof of the validity of the numerical method. Chapter six is the concluding chapter, where some reflections on the MHD effects on mixed convection flow will be made, in agreement with the experience and the results gathered in the analyses presented in the previous chapters. In the appendices special auxiliary functions and FORTRAN program listings are reported, to support the formulations used in the solution chapters.

EoR in alternative cosmological scenarios

The aim of this Thesis is to investigate the possibility that the observations related to the epoch of reionization can probe not only the evolution of the IGM state, but also the cosmological background in which this process occurs. In fact, the history of the IGM ionization is indeed affected by the evolution of the sources of ionizing photons that, under the assumption of a structure formation paradigm determined by the hierarchic growth of the matter uctuations, results strongly dependent on the characteristics of the background universe. For the purpose of our investigation, we have analysed the reionization history in innovative cosmological frameworks, still in agreement with the recent observational tests related to the SNIa and the CMB probes, comparing our results with the reionization scenario predicted by the commonly used LCDM cosmology. In particular, in this Thesis we have considered two different alternative universes. The first one is a at universe dominated at late epochs by a dynamic dark energy component, characterized by an equation of state evolving in time. The second cosmological framework we have assumed is a LCDM characterized by a primordial overdensity field having a non-Gaussian probability distribution. The reionization scenario have been investigated, in this Thesis, through semi-analytic approaches based on the hierarichic growth of the matter uctuations and on suitable assumptions concerning the ionization and the recombination of the IGM. We make predictions for the evolution and the distribution of the HII regions, and for the global features of reionization, that can be constrained by future observations. Finally, we brie y discuss the possible future prospects of this Thesis work.

Ricerca ed applicazione di nuovi metodi di progettazione meccanica e di industrial design

The present dissertation relates to methodologies and technics about industrial and mechanical design. The author intends to give a complete idea about the world of design, showing the theories of Quality Function Deployment and TRIZ, of other methods just like planning, budgeting, Value Analysis and Engineering, Concurrent Engineering, Design for Assembly and Manufactoring, etc., and their applications to five concrete cases. In these cases there are also illustrated design technics as CAD, CAS, CAM; Rendering, which are ways to transform an idea into reality. The most important object of the work is, however, the birth of a new methodology, coming up from a comparison between QFD and TRIZ and their integration through other methodologies, just like Time and Cost Analysis, learned and skilled during an important experience in a very famous Italian automotive factory.

Cosmological perturbations in generalized theories of gravity

The first part of the thesis concerns the study of inflation in the context of a theory of gravity called "Induced Gravity" in which the gravitational coupling varies in time according to the dynamics of the very same scalar field (the "inflaton") driving inflation, while taking on the value measured today since the end of inflation. Through the analytical and numerical analysis of scalar and tensor cosmological perturbations we show that the model leads to consistent predictions for a broad variety of symmetry-breaking inflaton's potentials, once that a dimensionless parameter entering into the action is properly constrained. We also discuss the average expansion of the Universe after inflation (when the inflaton undergoes coherent oscillations about the minimum of its potential) and determine the effective equation of state. Finally, we analyze the resonant and perturbative decay of the inflaton during (p)reheating. The second part is devoted to the study of a proposal for a quantum theory of gravity dubbed "Horava-Lifshitz (HL) Gravity" which relies on power-counting renormalizability while explicitly breaking Lorentz invariance. We test a pair of variants of the theory ("projectable" and "non-projectable") on a cosmological background and with the inclusion of scalar field matter. By inspecting the quadratic action for the linear scalar cosmological perturbations we determine the actual number of propagating degrees of freedom and realize that the theory, being endowed with less symmetries than General Relativity, does admit an extra gravitational degree of freedom which is potentially unstable. More specifically, we conclude that in the case of projectable HL Gravity the extra mode is either a ghost or a tachyon, whereas in the case of non-projectable HL Gravity the extra mode can be made well-behaved for suitable choices of a pair of free dimensionless parameters and, moreover, turns out to decouple from the low-energy Physics.

Retorica e mito in Giambattista Vico

The purpose of this thesis is to show that Vico had the constant aim, remained unaltered in time, to support the usefulness of Rhetoric. The awareness of the strength acquired by the “anti-rhetorical” movements, particularly by the Cartesians and the Logicians from Port-Royal, obliged Vico to elaborate some strategies and counter-moves that, little by little, became more and more complex and refined, till they inspired his main work, The New Science. By taking into consideration the most significant aspects of Vico’s speculation (topic, tropes, the formation of language, the development of human thought, the new conception of philology ), this work shows that they are part of a strategy worked out by the Neapolitan philosopher, in order to demonstrate the validity, the usefulness and the modernity of Rhetoric. Every aspect of Vico’s thought reaches its peak when Vico formulates his theory about myths, which he interprets as an expression of the primitive man’s necessities and demands. The point of view expressed by this doctorate thesis emphasizes that, despite the inevitable modifications that have taken place through the centuries, Vico’s thought keeps its substantial unity. So those subjects that critical literature tends to separate are, in reality, linked and unified.

A Multilevel Model with Time Series Components for the Analysis of Tribal Art Prices

In the present work we perform an econometric analysis of the Tribal art market. To this aim, we use a unique and original database that includes information on Tribal art market auctions worldwide from 1998 to 2011. In Literature, art prices are modelled through the hedonic regression model, a classic fixed-effect model. The main drawback of the hedonic approach is the large number of parameters, since, in general, art data include many categorical variables. In this work, we propose a multilevel model for the analysis of Tribal art prices that takes into account the influence of time on artwork prices. In fact, it is natural to assume that time exerts an influence over the price dynamics in various ways. Nevertheless, since the set of objects change at every auction date, we do not have repeated measurements of the same items over time. Hence, the dataset does not constitute a proper panel; rather, it has a two-level structure in that items, level-1 units, are grouped in time points, level-2 units. The main theoretical contribution is the extension of classical multilevel models to cope with the case described above. In particular, we introduce a model with time dependent random effects at the second level. We propose a novel specification of the model, derive the maximum likelihood estimators and implement them through the E-M algorithm. We test the finite sample properties of the estimators and the validity of the own-written R-code by means of a simulation study. Finally, we show that the new model improves considerably the fit of the Tribal art data with respect to both the hedonic regression model and the classic multilevel model.

Il caso del Maestro di Ozieri e la cultura pittorica del Cinquecento in Sardegna

La tesi si occupa del rapporto tra il Maestro di Ozieri e la produzione figurativa in Sardegna nella prima metà del Cinquecento. Studia l'uso delle incisioni. Valuta l'influenza della pittura romana e meridionale. Riflette sulla possibile identità straniera del pittore, sulla base delle molte somiglianze con artisti tedeschi e fiamminghi. Si occupa di comprendere quali possano essere considerate le opere autografe e quali quelle eseguite da seguaci e imitatori. Riformula alla luce dei confronti stilistici e delle ricerche in archivio la personalità dell'artista e la sua collocazione cronologica.

Targeting the p53–MDM2 interaction by the small-molecule MDM2 antagonist Nutlin-3a: a new challenged target therapy in adult Philadelphia positive acute lymphoblastic leukemia patients

The human p53 tumor suppressor, known as the “guardian of the genome”, is one of the most important molecules in human cancers. One mechanism for suppressing p53 uses its negative regulator, MDM2, which modulates p53 by binding directly to and decreasing p53 stability. In testing novel therapeutic approaches activating p53, we investigated the preclinical activity of the MDM2 antagonist, Nutlin-3a, in Philadelphia positive (Ph+) and negative (Ph-) leukemic cell line models, and primary B-Acute lymphoblastic leukemia (ALL) patient samples. In this study we demonstrated that treatment with Nutlin-3a induced grow arrest and apoptosis mediated by p53 pathway in ALL cells with wild-type p53, in time and dose-dependent manner. Consequently, MDM2 inhibitor caused an increase of pro-apoptotic proteins and key regulators of cell cycle arrest. The dose-dependent reduction in cell viability was confirmed in primary blast cells from Ph+ ALL patients with the T315I Bcr-Abl kinase domain mutation. In order to better elucidate the implications of p53 activation and to identify biomarkers of clinical activity, gene expression profiling analysis in sensitive cell lines was performed. A total of 621 genes were differentially expressed (p < 0.05). We found a strong down-regulation of GAS41 (growth-arrest specific 1 gene) and BMI1 (a polycomb ring-finger oncogene) (fold-change -1.35 and -1.11, respectively; p-value 0.02 and 0.03, respectively) after in vitro treatment as compared to control cells. Both genes are repressors of INK4/ARF and p21. Given the importance of BMI in the control of apoptosis, we investigated its pattern in treated and untreated cells, confirming a marked decrease after exposure to MDM2 inhibitor in ALL cells. Noteworthy, the BMI-1 levels remained constant in resistant cells. Therefore, BMI-1 may be used as a biomarker of response. Our findings provide a strong rational for further clinical investigation of Nutlin-3a in Ph+ and Ph-ALL.