Laser driven proton acceleration and beam shaping

In the race to obtain protons with higher energies, using more compact systems at the same time, laser-driven plasma accelerators are becoming an interesting possibility. But for now, only beams with extremely broad energy spectra and high divergence have been produced. The driving line of this PhD thesis was the study and design of a compact system to extract a high quality beam out of the initial bunch of protons produced by the interaction of a laser pulse with a thin solid target, using experimentally reliable technologies in order to be able to test such a system as soon as possible. In this thesis, different transport lines are analyzed. The first is based on a high field pulsed solenoid, some collimators and, for perfect filtering and post-acceleration, a high field high frequency compact linear accelerator, originally designed to accelerate a 30 MeV beam extracted from a cyclotron. The second one is based on a quadruplet of permanent magnetic quadrupoles: thanks to its greater simplicity and reliability, it has great interest for experiments, but the effectiveness is lower than the one based on the solenoid; in fact, the final beam intensity drops by an order of magnitude. An additional sensible decrease in intensity is verified in the third case, where the energy selection is achieved using a chicane, because of its very low efficiency for off-axis protons. The proposed schemes have all been analyzed with 3D simulations and all the significant results are presented. Future experimental work based on the outcome of this thesis can be planned and is being discussed now.

Measurements of ttbar Differential Cross Section at the ATLAS Experiment in pp Collisions at sqrt(s)=7TeV and sqrt(s)=8TeV

This PhD thesis presents two measurements of differential production cross section of top and anti-top pairs tt ̅ decaying in a lepton+jets final state. The normalize cross section is measured as a function of the top transverse momentum and the tt ̅ mass, transverse momentum and rapidity using the full 2011 proton-proton (pp) ATLAS data taking at a center of mass energy of √s=7 TeV and corresponding to an integrated luminosity of L=4.6 〖fb〗^(-1). The cross section is also measured at the particle level as a function of the hadronic top transverse momentum for highly energetic events using the full 2012 data taking at √s=8 TeV and with L=20 〖fb〗^(-1). The measured spectra are fully corrected for detector efficiency and resolution effects and are compared to several theoretical predictions showing a quite good agreement, depending on different spectra.

Partial Discharge Phenomena in Converter and Traction Transformers: Identification and Reliability

After the development of power electronics converters, the number of transformers subjected to non-sinusoidal stresses (including DC) has increased in applications such as HVDC links and traction (electric train power cars). The effects of non-sinusoidal voltages on transformer insulation have been investigated by many researchers, but still now, there are some issues that must be understood. Some of those issues are tackled in this Thesis, studying PD phenomena behavior in Kraft paper, pressboard and mineral oil at different voltage conditions like AC, DC, AC+DC, notched AC and square waveforms. From the point of view of converter transformers, it was found that the combined effect of AC and DC voltages produces higher stresses in the pressboard that those that are present under pure DC voltages. The electrical conductivity of the dielectric systems in DC and AC+DC conditions has demonstrated to be a critical parameter, so, its measurement and analysis was also taken into account during all the experiments. Regarding notched voltages, the RMS reduction caused by notches (depending on firing and overlap angles) seems to increase the PDIV. However, the experimental results show that once PD activity has incepted, the notches increase PD repetition rate and magnitude, producing a higher degradation rate of paper. On the other hand, the reduction of mineral oil stocks, their relatively low flash point as well as environmental issues, are factors that are pushing towards the use of esters as transformer insulating fluids. This PhD Thesis also covers the study of two different esters with the scope to validate their use in traction transformers. Mineral oil was used as benchmark. The complete set of dielectric tests performed in the three fluids, show that esters behave better than mineral oil in practically all the investigated conditions, so, their application in traction transformers is possible and encouraged.

Peak-to-Peak Output Current Ripple Analysis in Multiphase and Multilevel Inverters

Analysis of the peak-to-peak output current ripple amplitude for multiphase and multilevel inverters is presented in this PhD thesis. The current ripple is calculated on the basis of the alternating voltage component, and peak-to-peak value is defined by the current slopes and application times of the voltage levels in a switching period. Detailed analytical expressions of peak-to-peak current ripple distribution over a fundamental period are given as function of the modulation index. For all the cases, reference is made to centered and symmetrical switching patterns, generated either by carrier-based or space vector PWM. Starting from the definition and the analysis of the output current ripple in three-phase two-level inverters, the theoretical developments have been extended to the case of multiphase inverters, with emphasis on the five- and seven-phase inverters. The instantaneous current ripple is introduced for a generic balanced multiphase loads consisting of series RL impedance and ac back emf (RLE). Simplified and effective expressions to account for the maximum of the output current ripple have been defined. The peak-to-peak current ripple diagrams are presented and discussed. The analysis of the output current ripple has been extended also to multilevel inverters, specifically three-phase three-level inverters. Also in this case, the current ripple analysis is carried out for a balanced three-phase system consisting of series RL impedance and ac back emf (RLE), representing both motor loads and grid-connected applications. The peak-to-peak current ripple diagrams are presented and discussed. In addition, simulation and experimental results are carried out to prove the validity of the analytical developments in all the cases. The cases with different phase numbers and with different number of levels are compared among them, and some useful conclusions have been pointed out. Furthermore, some application examples are given.

Profili civilistici della vendita giudiziale di beni immobili in Italia e in Spagna

La tesi di dottorato ha come oggetto di studio gli aspetti sostanziali della vendita giudiziale da un punto di vista comparatistico tra Spagna e Italia. Si tratta di un tema che non è stato analizzato profondamente dalle più recenti dottrine spagnola e italiana, che è caratterizzato da una notevole complessità tecnica visto il suo forte carattere interdisciplinare (in particolare, processuale-sostanziale) e la cui vigenza attuale è stata intensificata dalla grande quantità di processi di esecuzione che in questo periodo di instabilità economica sono una constante nei Tribunali spagnoli e italiani. Il fatto che costituisca un’istituzione giuridica inquadrata nell’ambito del processo di espropriazione forzata fa sì che questa possieda un accentuato carattere processuale e, infatti, è il legislatore processuale che si occupa per la maggior parte del suo regime giuridico. Tuttavia, al di là di questa sua natura evidentemente processuale, essa produce una serie di effetti sostanziali di enorme importanza, che sono proprio l’oggetto della tesi di dottorato, nello specifico ambito dei beni immobili (considerando la grande importanza economica e pratica dei diritti di questa natura nella nostra realtà socio-economica).

Landscape ecology and genetics of the wolf in Italy

This PhD Thesis includes five main parts on diverse topics. The first two parts deal with the trophic ecology of wolves in Italy consequently to a recent increase of wild ungulates abundance. Data on wolf diet across time highlighted how wild ungulates are important food resource for wolves in Italy. Increasing wolf population, increasing numbers of wild ungulates and decreasing livestock consume are mitigating wolf-man conflicts in Italy in the near future. In the third part, non-invasive genetic sampling techniques were used to obtain genotypes and genders of about 400 wolves. Thus, wolf packs were genetically reconstructed using diverse population genetic and parentage software. Combining the results on pack structure and genetic relatedness with sampling locations, home ranges of wolf packs and dispersal patterns were identified. These results, particularly important for the conservation management of wolves in Italy, illustrated detailed information that can be retrieved from genetic identification of individuals. In the fourth part, wolf locations were combined with environmental information obtained as GIS-layers. Modern species distribution models (niche models) were applied to infer potential wolf distribution and predation risk. From the resulting distribution maps, information pastures with the highest risk of depredation were derived. This is particularly relevant as it allows identifying those areas under danger of carnivore attack on livestock. Finally, in the fifth part, habitat suitability models were combined with landscape genetic analysis. On one side landscape genetic analyses on the Italian wolves provided new information on the dynamics and connectivity of the population and, on the other side, a profound analysis of the effects that habitat suitability methods had on the parameterization of landscape genetic analyses was carried out to contributed significantly to landscape genetic theory.

Ground penetrating radar early-time technique for soil electromagnetic parameters estimation

In recent years, thanks to the technological advances, electromagnetic methods for non-invasive shallow subsurface characterization have been increasingly used in many areas of environmental and geoscience applications. Among all the geophysical electromagnetic methods, the Ground Penetrating Radar (GPR) has received unprecedented attention over the last few decades due to its capability to obtain, spatially and temporally, high-resolution electromagnetic parameter information thanks to its versatility, its handling, its non-invasive nature, its high resolving power, and its fast implementation. The main focus of this thesis is to perform a dielectric site characterization in an efficient and accurate way studying in-depth a physical phenomenon behind a recent developed GPR approach, the so-called early-time technique, which infers the electrical properties of the soil in the proximity of the antennas. In particular, the early-time approach is based on the amplitude analysis of the early-time portion of the GPR waveform using a fixed-offset ground-coupled antenna configuration where the separation between the transmitting and receiving antenna is on the order of the dominant pulse-wavelength. Amplitude information can be extracted from the early-time signal through complex trace analysis, computing the instantaneous-amplitude attributes over a selected time-duration of the early-time signal. Basically, if the acquired GPR signals are considered to represent the real part of a complex trace, and the imaginary part is the quadrature component obtained by applying a Hilbert transform to the GPR trace, the amplitude envelope is the absolute value of the resulting complex trace (also known as the instantaneous-amplitude). Analysing laboratory information, numerical simulations and natural field conditions, and summarising the overall results embodied in this thesis, it is possible to suggest the early-time GPR technique as an effective method to estimate physical properties of the soil in a fast and non-invasive way.

Design and experimental characterization of antennas and wireless systems for innovative wearable and implantable ultra low–power applications

The present PhD thesis exploits the design skills I have been improving since my master thesis’ research. A brief description of the chapters’ content follows. Chapter 1: the simulation of a complete front–end is a very complex problem and, in particular, is the basis upon which the prediction of the overall performance of the system is possible. By means of a commercial EM simulation tool and a rigorous nonlinear/EM circuit co–simulation based on the Reciprocity Theorem, the above–mentioned prediction can be achieved and exploited for wireless links characterization. This will represent the theoretical basics of the entire present thesis and will be supported by two RF applications. Chapter 2: an extensive dissertation about Magneto–Dielectric (MD) materials will be presented, together with their peculiar characteristics as substrates for antenna miniaturization purposes. A designed and tested device for RF on–body applications will be described in detail. Finally, future research will be discussed. Chapter 3: this chapter will deal with the issue regarding the exploitation of renewable energy sources for low–energy consumption devices. Hence the problem related to the so–called energy harvesting will be tackled and a first attempt to deploy THz solar energy in an innovative way will be presented and discussed. Future research will be proposed as well. Chapter 4: graphene is a very promising material for devices to be exploited in the RF and THz frequency range for a wide range of engineering applications, including those ones marked as the main research goal of the present thesis. This chapter will present the results obtained during my research period at the National Institute for Research and Development in Microtechnologies (IMT) in Bucharest, Romania. It will concern the design and manufacturing of antennas and diodes made in graphene–based technology for detection/rectification purposes.

Sustainable processes using heterogeneous acid catalysts. Some examples of industrial interest.

In recent years the need for the design of more sustainable processes and the development of alternative reaction routes to reduce the environmental impact of the chemical industry has gained vital importance. Main objectives especially regard the use of renewable raw materials, the exploitation of alternative energy sources, the design of inherently safe processes and of integrated reaction/separation technologies (e.g. microreactors and membranes), the process intensification, the reduction of waste and the development of new catalytic pathways. The present PhD thesis reports results derived during a three years research period at the School of Chemical Sciences of Alma Mater Studiorum-University of Bologna, Dept. of Industrial Chemistry and Materials (now Dept. of Industrial Chemistry “Toso Montanari”), under the supervision of Prof. Fabrizio Cavani (Catalytic Processes Development Group). Three research projects in the field of heterogeneous acid catalysis focused on potential industrial applications were carried out. The main project, regarding the conversion of lignocellulosic materials to produce monosaccharides (important intermediates for production of biofuels and bioplatform molecules) was financed and carried out in collaboration with the Italian oil company eni S.p.A. (Istituto eni Donegani-Research Center for non-Conventional Energies, Novara, Italy) The second and third academic projects dealt with the development of green chemical processes for fine chemicals manufacturing. In particular, (a) the condensation reaction between acetone and ammonia to give triacetoneamine (TAA), and (b) the Friedel-Crafts acylation of phenol with benzoic acid were investigated.

Studio del metodo dell'assorbimento diretto della CO2 per l'analisi del radiocarbonio

L’attuale rilevanza rappresentata dalla stretta relazione tra cambiamenti climatici e influenza antropogenica ha da tempo posto l’attenzione sull’effetto serra e sul surriscaldamento planetario così come sull’aumento delle concentrazioni atmosferiche dei gas climaticamente attivi, in primo luogo la CO2. Il radiocarbonio è attualmente il tracciante ambientale per eccellenza in grado di fornire mediante un approccio “top-down” un valido strumento di controllo per discriminare e quantificare il diossido di carbonio presente in atmosfera di provenienza fossile o biogenica. Ecco allora che ai settori applicativi tradizionali del 14C, quali le datazioni archeometriche, si affiancano nuovi ambiti legati da un lato al settore energetico per quanto riguarda le problematiche associate alle emissioni di impianti, ai combustibili, allo stoccaggio geologico della CO2, dall’altro al mercato in forte crescita dei cosiddetti prodotti biobased costituiti da materie prime rinnovabili. Nell’ambito del presente lavoro di tesi è stato quindi esplorato il mondo del radiocarbonio sia dal punto di vista strettamente tecnico e metodologico che dal punto di vista applicativo relativamente ai molteplici e diversificati campi d’indagine. E’ stato realizzato e validato un impianto di analisi basato sul metodo radiometrico mediante assorbimento diretto della CO2 ed analisi in scintillazione liquida apportando miglioramenti tecnologici ed accorgimenti procedurali volti a migliorare le performance del metodo in termini di semplicità, sensibilità e riproducibilità. Il metodo, pur rappresentando generalmente un buon compromesso rispetto alle metodologie tradizionalmente usate per l’analisi del 14C, risulta allo stato attuale ancora inadeguato a quei settori applicativi laddove è richiesta una precisione molto puntuale, ma competitivo per l’analisi di campioni moderni ad elevata concentrazione di 14C. La sperimentazione condotta su alcuni liquidi ionici, seppur preliminare e non conclusiva, apre infine nuove linee di ricerca sulla possibilità di utilizzare questa nuova classe di composti come mezzi per la cattura della CO2 e l’analisi del 14C in LSC.

Electrospun Polymeric Scaffolds with Enhanced Biomimetic Properties for Tissue Engineering Applications

This PhD Thesis is focused on the development of fibrous polymeric scaffolds for tissue engineering applications and on the improvement of scaffold biomimetic properties. Scaffolds were fabricated by electrospinning, which allows to obtain scaffolds made of polymeric micro or nanofibers. Biomimetism was enhanced by following two approaches: (1) the use of natural biopolymers, and (2) the modification of the fibers surface chemistry. Gelatin was chosen for its bioactive properties and cellular affinity, however it lacks in mechanical properties. This problem was overcome by adding poly(lactic acid) to the scaffold through co-electrospinning and mechanical properties of the composite constructs were assessed. Gelatin effectively improves cell growth and viability and worth noting, composite scaffolds of gelatin and poly(lactic acid) were more effective than a plain gelatin scaffold. Scaffolds made of pure collagen fibers were fabricated. Modification of collagen triple helix structure in electrospun collagen fibers was studied. Mechanical properties were evaluated before and after crosslinking. The crosslinking procedure was developed and optimized by using - for the first time on electrospun collagen fibers - the crosslinking reactant 1,4-butanediol diglycidyl ether, with good results in terms of fibers stabilization. Cell culture experiments showed good results in term of cell adhesion and morphology. The fiber surface chemistry of electrospun poly(lactic acid) scaffold was modified by plasma treatment. Plasma did not affect thermal and mechanical properties of the scaffold, while it greatly increased its hydrophilicity by the introduction of carboxyl groups at the fiber surface. This fiber functionalization enhanced the fibroblast cell viability and spreading. Surface modifications by chemical reactions were conducted on electrospun scaffolds made of a polysophorolipid. The aim was to introduce a biomolecule at the fiber surface. By developing a series of chemical reactions, one oligopeptide every three repeating units of polysophorolipid was grafted at the surface of electrospun fibers.

Paleosol-based stratigraphy of late Quaternary deposits from the Po basin, between Bologna and the Po river (Northern Italy)

Stratigraphic studies carried out over the last decades in Italy and elsewhere testify a growing interest in Quaternary deposits and in the influence of climate change on their architecture. The subsurface of the Po Plain, in its topmost portion, is made up of alluvial deposits organized in depositional cycles at different scales. This PhD thesis provides millennial-scale stratigraphic reconstruction of the Late Pleistocene-Holocene deposits beneath the southern Po Plain, based on basin-scale correlation of laterally-extensive buried soil horizons. Far from the aim of characterizing palaeosols from a mineralogical and geochemical point of view, we focused on the physical and stratigraphic significance of these horizons. In the Bologna urban area, which hosts an abundance of stratigraphic data, the correlation between seventeen continuously-cored boreholes led to the identification of five vertically-stacked palaeosol-bounded sequences within the 14C time window. In a wide portion of the alluvial plain north of Bologna, far away from the Apenninic margin and from the Po River, where subsurface stratigraphic architecture is dominated by markedly lenticular sediment bodies, palaeosols revealed to be the only stratigraphic marker of remarkable lateral continuity. These horizons are characterized by peculiar resistance values, which make them easily identifiable via pocket penetration tests. Palaeosols reveal specific geometric relationships with the associated alluvial facies associations, allowing reliable estimates of soil development as a function of alluvial dynamics. With the aid of sixty new radiocarbon dates, a reliable age attribution and likely time intervals of exposure were assigned to each palaeosol. Vertically-stacked palaeosols delimitate short-term depositional cycles, likely related to the major episodes of climatic change of the last 40 ky. Through integration of stratigraphic data with 750 archaeological reports from the Bologna area, the impact of human settlements on depositional and pedogenic processes during the late Holocene was investigated.

Stream sediments analysis for geochemical mapping of Romagna Apennines (Northern Italy): monitoring and management tool of environmental resources at various scales

Geochemical mapping is a valuable tool for the control of territory that can be used not only in the identification of mineral resources and geological, agricultural and forestry studies but also in the monitoring of natural resources by giving solutions to environmental and economic problems. Stream sediments are widely used in the sampling campaigns carried out by the world's governments and research groups for their characteristics of broad representativeness of rocks and soils, for ease of sampling and for the possibility to conduct very detailed sampling In this context, the environmental role of stream sediments provides a good basis for the implementation of environmental management measures, in fact the composition of river sediments is an important factor in understanding the complex dynamics that develop within catchment basins therefore they represent a critical environmental compartment: they can persistently incorporate pollutants after a process of contamination and release into the biosphere if the environmental conditions change. It is essential to determine whether the concentrations of certain elements, in particular heavy metals, can be the result of natural erosion of rocks containing high concentrations of specific elements or are generated as residues of human activities related to a certain study area. This PhD thesis aims to extract from an extensive database on stream sediments of the Romagna rivers the widest spectrum of informations. The study involved low and high order stream in the mountain and hilly area, but also the sediments of the floodplain area, where intensive agriculture is active. The geochemical signals recorded by the stream sediments will be interpreted in order to reconstruct the natural variability related to bedrock and soil contribution, the effects of the river dynamics, the anomalous sites, and with the calculation of background values be able to evaluate their level of degradation and predict the environmental risk.

Simulation Guided Navigation in cranio-maxillo-facial surgery: a new approach to improve intraoperative three-dimensional accuracy and reproducibility during surgery.

The aim of this PhD thesis " Simulation Guided Navigation in cranio- maxillo- facial surgery : a new approach to Improve intraoperative three-dimensional accuracy and reproducibility during surgery ." was at the center of its attention the various applications of a method introduced by our School in 2010 and has as its theme the increase of interest of reproducibility of surgical programs through methods that in whole or in part are using intraoperative navigation. It was introduced in Orthognathic Surgery Validation a new method for the interventions carried out according to the method Simulation Guided Navigation in facial deformities ; was then analyzed the method of three-dimensional control of the osteotomies through the use of templates and cutting of plates using the method precontoured CAD -CAM and laser sintering . It was finally proceeded to introduce the method of piezonavigated surgery in the various branches of maxillofacial surgery . These studies have been subjected to validation processes and the results are presented .

Molecular variability of Meningococcal antigens in carriage and disease strains and in other Neisseria species

This PhD thesis is focused on the study of the molecular variability of some specific proteins, part of the outer membrane of the pathogen Neisseria meningitidis, and described as protective antigens and important virulence factors. These antigens have been employed as components of the vaccine developed by Novartis Vaccines against N. meningitidis of serogroup B, and their variability in the meningococcal population is a key aspect when the effect of the vaccine is evaluated. The PhD project has led to complete three major studies described in three different manuscritps, of which two have been published and the third is in preparation. The thesis is structured in three main chapters, each of them dedicated to the three studies. The first, described in Chapter 1, is specifically dedicated to the analysis of the molecular conservation of meningococcal antigens in the genomes of all species classified in the genus Neisseria (Conservation of Meningococcal Antigens in the Genus Neisseria. A. Muzzi et al.. 2013. mBio 4 (3)). The second study, described in Chapter 2, focuses on the analysis of the presence and conservation of the antigens in a panel of bacterial isolates obtained from cases of the disease and from healthy individuals, and collected in the same year and in the same geographical area (Conservation of fHbp, NadA, and NHBA in carrier and pathogenic isolates of Neisseria meningitidis collected in the Czech Republic in 1993. A. Muzzi et al.. Manuscript in preparation). Finally, Chapter 3 describes the molecular features of the antigens in a panel of bacterial isolates collected over a period of 50 years, and representatives of the epidemiological history of meningococcal disease in the Netherlands (An Analysis of the Sequence Variability of Meningococcal fHbp, NadA and NHBA over a 50-Year Period in the Netherlands. S. Bambini et al.. 2013. PloS one e65043).