Dipartimento di Fisica - Tesi di Dottorato
Permanent URI for this collectionhttps://lisa.unical.it/handle/10955/35
Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento di Fisica dell'Università della Calabria.
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Item Chemical characterization of atmospheric aerosols from natural and anthropogenic sources in the Mediterranean area(Università della Calabria, 2019-10-14) Moretti, Sacha; Carbone, Vincenzo; Sprovieri, Francesca; Naccarato, AttilioThe Mediterranean Sea basin constitutes a semi-enclosed area where atmospheric particles originating from natural and anthropogenic continental sources and gas-to-particle conversion processes are present at all times. The area is, in fact, located to the south of highly populated European countries characterized by industrial, semi-industrial, and rural economies, and to the north of Africa, which includes the Sahara desert. Detailed wind trajectory analysis reported in previous research studies show that more than 60% of air masses crossing the Mediterranean originate from the north-northwest sector, containing particles emitted or derived from industrial and urban sources, whereas 13–16% of air masses coming from the Sahara region carrying predominantly mineral dust. The transport of Saharan dust occurs mostly during the spring and summer seasons and causes sporadic crustal aerosol pulses to the Mediterranean area. On the other hand, aerosol scavenging by precipitation during the rainy season (from October to May) reduces aerosol concentrations. Summer is also characterized by low inversion layers and strong sunlight conditions, causing photochemical smog. Moreover, forest fires, which occur during the summer months in the Mediterranean region and in North Africa, increase black carbon and fine particle emissions. In this frame, it is clear enough that specific meteorological conditions result in high temporal variability of aerosol concentrations. There is strong evidence on the relationship between short-term and long-term exposure to atmospheric particles, with adverse health effects. Therefore, the study on atmospheric Particulate Matter (PM) (solid or liquid particles dispersed in the atmosphere which may persist for long times to undergo transport and diffusion phenomena), and the relative chemical composition of the two particle size fractions PM2.5, (aerodynamic diameter ≤ 2.5 μm) and PM10 (aerodynamic diameter ≤ 10 μm), is essential to evaluate the effect of the PM on human health and environment. The present work of thesis developed during the Ph.D. is focused on the chemical characterization of aerosol in the Mediterranean area through a monitoring program which has foreseen a number of oceanographic campaigns performed in the Mediterranean sea onboard the CNR-research vessel in the framework of the ongoing MEDOCEANOR measurements program as well as long-term measurements carried out on-land, specifically at the high altitude GAW observatory “Monte Curcio” of the CNR-IIA (1780 m a.s.l.), located on the Sila massif, Southern Italy, and thus able to intercept long-range transport air masses and across a number of monitoring sites (i.e., coastal, urban, rural sites etc.) distributed in the south of Italy as part of the I-AMICA regional network. The concentration of aerosol size fractions and its chemical composition performed at permanent ground-based stations as well as during oceanographic measurement campaigns have been analyzed in order to assess a spatially and temporally consistent measurement data across Mediterranean basin, and to investigate the main natural and anthropogenic sources affecting the air quality using source apportionment techniques. The seasonal oceanographic campaigns developed along different routes in the western sector of the Mediterranean Sea basin, and aimed to study the influence of natural and anthropogenic sources of PM and associated levels of pollutants. Chemical analysis assisted by the receptor models, identified, in particular, six main sources: crustal, volcanic, biomass burning, marine spray, industrial and vehicular traffic. The carbonaceous content in the PM sampled in Monte Curcio station shows seasonal trends for Organic Carbon (OC) and Elemental Carbon (EC) in both PM size fractions. The concentrations during the warm season are higher than those observed during the cold season and the annual levels of EC and OC were lower than those observed at the other four monitoring sites as part of the regional network “I-AMICA” distributed in southern Italy (Capo Granitola, Lamezia Terme, Lecce; Naples) due to different environmental conditions (eg, coastal/marine, suburban and urban) characterizing these sampling sites compared to “Monte Curcio” remote site. In particular, both OC and EC average concentrations were minimal at Monte Curcio and increased in the following order: remote < coastal/marine < suburban < urban (i.e., Monte Curcio < Capo Granitola < Lamezia Terme < Lecce < Naples). The Secondary Organic Carbon (SOC) was mainly present in PM2.5 at all sites, and higher SOC/OC ratios were observed at the urban and suburban site. Indeed, the yearly average SOC in Monte Curcio station has been estimated as 52% of OC in PM2.5 and representing, on average, the major mass contributes to PM2.5 during the cold season. Furthermore, the receptor models used shown differences among the possible sources of carbonaceous aerosol between different seasons. The cold season was characterized by aerosol mainly coming from the long-range transport, while during the warm season it is influenced by local and regional sources. In the following Chapters, the results have been presented and discussed.Item Ion energization in the terrestrial magnetosphere(Università della Calabria, 2019-10-29) Catapano, Filomena; Zimbardo, Gaetano; Delcourt, Dominique; Carbone, Vincemzo; Retinò, AlessandroItem Laser action in liquid crystals: from random to periodic syatems(2007) Ferjani, Sameh; Strangi, Giuseppe; Versace, CarloItem Towards more sustainable organic processes : heterocyclizations in non-conventional solvents(2017-09-19) Maner, Asif S.; Carbone, Vincenzo; Gabriele, Bartolo; Mancuso, RaffaellaThis thesis reports the synthesis of important heterocyclic derivatives by iodocyclization, carbonylation and cycloisomerization reactions in Non-Conventionl solvents like deep eutectic solvents (DES) and Ionic Liquids (ILs). In chapter one general aspects of green and sustainable chemistry and introduction to eco-friendly green solvents such as water, DES, ScCO2 and ILs are described. Carbonylation processes, their advantages, types were described along with the application of transition metal catalysis in the carbonylation reactions with mechanistic approaches discussed. In chapter two, we describe a convenient and general method for the synthesis of substituted thiophenes through heterocyclodehydration and iodocyclization of readily available 1-mercapto-3-alkyn-2-ols in DES as the solvents. In chapter three we discuss a convenient carbonylative approach to 2-oxazolidinone derivatives carried out in an ionic liquid as the solvent (EmimEtSO4) is presented. It is based on the sequential concatenation of two catalytic cycles, both catalyzed by the same metal species (auto-tandem catalysis). In chapter four we present iodocyclization reactions to obtain iodinated isobenzofuranones and isochromenones by iodolactonization of 2-alkynyl benzoic acids in ionic liquids. In particular here we have developed divergent syntheses of (E)-3-(iodoalkylidene) isobenzofuran-1(3H)-ones and 4-iodo-1H-isochromen-1-ones by base-free Iodolactonization of 2-alkynylbenzoic acids in ionic liquids. In chapter five we report the cycloisomerization of readily available 2-alkynylbenzoic acids using an ionic liquid as the reaction medium in the presence of CuCl2 as a simple and inexpensive catalyst. Although in principle two different cyclization pathways can be followed, leading to either 5-exo-dig mode or 6-endo-dig mode, we have found that substrates bearing an aryl group on the triple bond or a terminal triple bond can be selectively converted into the isobenzofuranone derivatives, using N-ethyl-N-methylmorpholinium dicyanamide (Mor1,2N(CN)2) as the solvent. On the other hand, and in a complementary manner, substrates substituted with an alkyl or an alkenyl group on the triple bond selectively led to isochromenones when the reaction was carried out EmimEtSO4 and with excellent recyclability of the catalyst/ionic liquid system.Item Improving oilfield performance enabling horizontal drilling techniques: developments and optimization of standard and special measures for a real case study(2017-11-13) Al Taie, Amer Abdulhakim; Carbone, Vincenzo; Romagnoli, RaffaeleDrilling technique is a crucial issue to pay attention to. Drilling a horizontal well has a great interest to the oil and gas industry since nowadays it provides attractive means for improving both production rate and yet the recovery efficiency. The great improvements in drilling technology make it possible to drill horizontally no matter how complex are the trajectories and how deep it is suppose to reach. This study aims at presenting the optimal design aspects of a horizontal well. Design aspects include the selection of bit and casing sizes, detection of setting depths and drilling fluid density, casing, hydraulics, well profile, and construction of drill string simulator. When many vertical wells exist, an oil field named (Z14 field) should be designated to have a short radius horizontal well able to increasing the productivity and to promote the developing of the field itself. A single build profile with build rate 90 deg/100ft is constructed based on geological data. A drill string simulator composed of soft-string model and buckling tendency is constructed to predict torque and drag of string for six operating conditions. These conditions are pick-up, slack-off, sliding, pick-up with rotation, slack-off with rotation and drilling with rotation. Results of loads analysis showed that the suggested drill string can be used without exceeding torsional, tensile and buckling strengths. Analysis of single build profile showed that the torque and drag while drilling horizontal well could be minimized by drilling with low build rate, employing lighter pipe, and improving the lubricating capability with oil base mud (low friction forces). A finite element model was constructed to predict inclination tendency for multistabilizer rotary BHA in three dimensions, static condition. The bottom hole assembly was idealized with beam element capable of resisting axial forces, bending moments about the two principal axes, and twisting moments about its centroidal axis. Bit and stabilizer were treated as contact point and restricted from movement in all directions. Each element is loaded with gravity and normal contact forces. Model validation showed closer agreement between the model and Jiazhi's method (analytic) for slick, single, and two stabilizers BHA, compared to Akgun results. Predictions with finite element model showed that for building assembly, the weight on bit had small effect on bit side force especially in high angle wells. Also inclination tendency (building, dropping) would depend on position of the stabilizer, diameter of drillcollar behind the bit, and number of stabilizers.Item Rischio sismico ambientale e degli edifici: analisi tecnica HVSR - Aspetti teorici e aspetti sperimentali(2017-07-17) Magarò, Floriana; Carbone, Vincenzo; Zinno, RaffaeleItem TiO2 nanotubes in nanotechnologies(2017-10-10) Jimenez, Leticia; Versace, CarloItem Synthesis and characterization of nanomaterials: graphene, silicene and carbon nano- onions(2017-10-20) Osman, Salih Mohamed; Critelli, Salvatore; Caputi, LorenzoThe electronic structure of the graphene/Ni(111) system was investigated by means of electron energy-loss spectroscopy (EELS). A single layer of graphene has been obtained on Ni(111) by dissociation of ethylene. Angle-resolved EEL spectra show a low energy plasmon dispersing up to about 2 eV, resulting from fluctuation of a charge density located around the Fermi energy, due to hybridization between Ni and graphene states. The dispersion is typical of a two-dimensional charge layer, and the calculated Fermi velocity is a factor of ~0.5 lower than in isolated graphene. The interface-π plasmon, related to interband transitions involving hybridized states at the K point of the hexagonal Brillouin zone, has been measured at different scattering geometries. The resulting dispersion curve exhibits a square root behavior, indicating also in this case a two-dimensional character of the interface charge density. As well, it has been shown that it is possible to use EELS in the reflection mode to measure the fine structure of the carbon K-edge in monolayer graphene on Ni(111), thus demonstrating that reflection EELS is a very sensitive tool, particularly useful in cases where the TEM-based ELNES cannot be applied. Clean Ag(111) surface and the two phases of silicene on Ag(111), mixed (4×4, √13×√13R19°, 2√3×2√3R30°) and 2√3×2√3R30, have been studied by XPS, LEED and EELS. EEL spectra of the Ag(111) surface covered by silicene in the (4×4, √13×√13R19°, 2√3×2√3R30°) mixed phase shows a well-defined plasmon peak whose center is located at about 1.75 eV. The 2√3×2√3R30° phase shows EEL spectra that exhibit a peak located at about 0.75 eV loss, which moves clearly towards higher energies with increasing momentum transfer. The typical parabolic dispersion relation obtained from such spectra confirms that the peak is due to a collective excitation which is evidently associated to the silicene layer. These plasmons associated to silicene have never been observed in the past. Our results show that the plasmonic properties of silicene on Ag(111) are strongly dependent on the geometrical arrangement of Si atoms with respect to the substrate. Carbonaceous nanomaterials have been obtained by underwater arc discharge between graphite electrodes. TEM images showed that the resulting particles suspended in water consist of CNOs with other carbonaceous materials such as CNTs and graphene. We observed for the first time the formation of a solid agglomerate on the cathode surface. Raman and TEM studies revealed that the agglomerate is made exclusively of CNOs. The defragmentation of such agglomerate allows to obtain CNOs free of other carbonaceous materials without the complex purification procedures needed for floating nanomaterialsItem High-energy resummation in semi-hard processes at the LHC(2017-06-30) Celiberto, Francesco Giovanni; Carbone, Vincenzo; Papa, AlessandroSemi-hard processes in the large center-of-mass energy limit offer us an exclusive chance to test the dynamics behind strong interactions in kinematical sectors so far unexplored, the high luminosity and the record energies of the LHC providing us with a richness of useful data. In the Regge limit, s jtj, fixed-order calculations in perturbative QCD based on collinear factorisation miss the effect of large energy logarithms, which are so large to compensate the small QCD coupling s and must therefore be accounted for to all perturbative orders. The BFKL approach represents the most powerful tool to perform the resummation to all orders of these large logarithms both in the LLA, which means inclusion of all terms proportional to ( s ln(s))n, and NLA, which means inclusion of all terms proportional to s( s ln(s))n. The inclusive hadroproduction of forward jets with high transverse momenta separated by a large rapidity gap at the LHC, the so-called Mueller–Navelet jets, has been one of the most studied reactions so far. Interesting observables associated to this process are the azimuthal correlation momenta, showing a very good agreement with experimental data at the LHC. However, new BFKL-sensitive observables should be considered in the context of the LHC physics program. With the aim the to further and deeply probe the dynamics of QCD in the Regge limit, we give phenomenological predictions for four distinct semi-hard process. On one hand, we continue the analysis of reactions with two objects identified in the final state (i) by addressing open problems in the Mueller– Navelet sector and (ii) by studying the inclusive dihadron production in the full NLA BKFL accuracy. Hadrons can be detected at the LHC at much smaller values of the transverse momentum than jets, allowing us to explore an additional kinematical range, complementary to the one studied typical of Mueller– Navelet jets. Furthermore, this process permits to constrain not only the parton distribution functions for the initial proton, but also the parton fragmentation functions describing the detected hadron in the final state. On the other hand, we show how inclusive multi-jet production processes allow us to define new, generalised and suitable BFKL observables, where transverse momenta and rapidities of the tagged jets, well separated in rapidity from each other, appear in new combinations. We give the first phenomenological predictions for the inclusive three-jet production, encoding the effects of higher-order BFKL corrections. Then, making use of the same formalism, we present the first complete BFKL analysis for the four-jet production.Item High-energy resummation in semi-hard processes at the LHC(2017-06-30) Celiberto, Francesco Giovanni; Carbone, Vincenzo; Papa, AlessandroSemi-hard processes in the large center-of-mass energy limit offer us an exclusive chance to test the dynamics behind strong interactions in kinematical sectors so far unexplored, the high luminosity and the record energies of the LHC providing us with a richness of useful data. In the Regge limit, s jtj, fixed-order calculations in perturbative QCD based on collinear factorisation miss the effect of large energy logarithms, which are so large to compensate the small QCD coupling s and must therefore be accounted for to all perturbative orders. The BFKL approach represents the most powerful tool to perform the resummation to all orders of these large logarithms both in the LLA, which means inclusion of all terms proportional to ( s ln(s))n, and NLA, which means inclusion of all terms proportional to s( s ln(s))n. The inclusive hadroproduction of forward jets with high transverse momenta separated by a large rapidity gap at the LHC, the so-called Mueller–Navelet jets, has been one of the most studied reactions so far. Interesting observables associated to this process are the azimuthal correlation momenta, showing a very good agreement with experimental data at the LHC. However, new BFKL-sensitive observables should be considered in the context of the LHC physics program. With the aim the to further and deeply probe the dynamics of QCD in the Regge limit, we give phenomenological predictions for four distinct semi-hard process. On one hand, we continue the analysis of reactions with two objects identified in the final state (i) by addressing open problems in the Mueller– Navelet sector and (ii) by studying the inclusive dihadron production in the full NLA BKFL accuracy. Hadrons can be detected at the LHC at much smaller values of the transverse momentum than jets, allowing us to explore an additional kinematical range, complementary to the one studied typical of Mueller– Navelet jets. Furthermore, this process permits to constrain not only the parton distribution functions for the initial proton, but also the parton fragmentation functions describing the detected hadron in the final state. On the other hand, we show how inclusive multi-jet production processes allow us to define new, generalised and suitable BFKL observables, where transverse momenta and rapidities of the tagged jets, well separated in rapidity from each other, appear in new combinations. We give the first phenomenological predictions for the inclusive three-jet production, encoding the effects of higher-order BFKL corrections. Then, making use of the same formalism, we present the first complete BFKL analysis for the four-jet production.