The thesis here presented is the result of a PhD research, with the aim to build a program able to solve the non-relativistic eigenvalue problem for the so-called cluster and nuclei (in particular the Beryllium-9 nucleus), in order to study them through the use of Effective Field Theory (EFT) potentials. After a brief introduction, that will show why this type of nuclei are important in the study of stellar nucleosynthesis, I introduce the Hyperspherical Harmonics basis with which the calculations were carried out. The following chapter has the momentum space as the main subject, ending with some results from the program. EFT and cluster nuclei are then introduced in the next chapter, together with the interaction I used for the cluster systems. The second to last chapter shows the results of the code, able to calculate the ground state of Carbon-12 and Beryllium-9 nuclei, two important nuclei in the process of stellar nucleosynthesis. The last chapter contains a brief summary and the future outlook on this research.

The technologies for the use of biomass as an energy source are not always environmental friendly process: wood combustion, for example, can be a rather a dirty process that causes the release in air of several dangerous compounds. For those reasons it is important to develop approaches aimed at the use of biomass in a cleanest way, avoiding, whenever possible, direct combustion of solid biomass and, rather, pursuing fuel upgrade processes allowing a better combustion or direct conversion to electricity through fuel cells. The products originating from the gasification process mainly comprise a mixture of the permanent gases CO, CO2, H2 and CH4, steam, char, tars and ash. The raw synthesis gas needs to be cleaned from tars before it may be upgraded to other commodities. In most cases if tars deposit on the catalyst surface it will block the active sites i.e., carbon acts as catalyst poison. Furthermore, tars in the raw gas can also cause corrosion and blockage of pipes in downstream process equipment. One of the main challenges in biomass gasification is the minimization of tar content in the product gas in combination with optimization of the gas composition. That is, to reduce the tar content as much as possible and to increase the permanent gases. In this context, it is especially interesting the development of technologies for syngas production (i.e. synthesis gas) through biomass gasification and for syngas utilization in fuel cells system, in order to produce energy from renewable resources. In detail the SOFCs (Solid Oxide Fuel Cell) work at high temperatures, and can be fed with different type of fuels, such as methane, carbon monoxide and hydrogen. Thus, the syngas produced by means of biomass gasification, seems to be a suitable fuel for this kind of cells. This chance is particularly interesting, considering that small and medium size conversion plant technologies could be integrated in a distributed energy generation model that is expected to increase its diffusion. The aim of the present project is to verify the possibility of coupling a biomass gasifier with a SOFC for energy production. The use of steam as gasifying agent increases the syngas heating value in comparison with the use of air, since its nitrogen content cause a dilution of the obtained gaseous fuel. Moreover, another beneficial effect in using water steam, is the increase of the H2 percentage up to 50 % in volume. A high hydrogen concentration is kindly recommended if the final aim is to feed a fuel cell. However, the disadvantages of the steam gasification are the lower steam reactivity, comparing with the oxygen one, and the decreasing of the temperature inside the reactor due to the endothermicity of the main reactions. Thus, it is necessary to supply indirectly the heat of reaction. In fluidized bed gasifiers, the bed material acts as solid heat carriers and often provides the heat from char combustion; however fixed bed gasifier are more suitable for small scale application, especially when biomass is used as feedstock . In the first part of this project a small scale (semi continuous, fixed-bed) gasifier has been designed and built. The syngas composition produced has been analyzed and the hydrogen concentration was approximately 60%. In a second stage the plant has been modified in a continuous fixed-bed gasifier, to perform long test duration. The gas composition slightly changes, even if anyway exploitable in fuel cell. Between the gasifier and the fuel cell, a gas cleaning stage has been foreseen. A catalyst is needed for tar cracking. A series of air-gasification tests have been run in a fluidized bed gasifier to test two different catalysts: dolomite and iron. The results on tar concentrations have confirmed the higher efficiency of dolomite in tar cracking. Then, a catalytic filter filled with dolomite has been placed after the fixed bed gasifier for tar abatement. Finally, some tests coupling the gasifier with a solid oxide fuel cells stack have been run. The temperature field measured during the experimental activity by some K-thermocouples has been elaborated to estimate an apparent thermal conductivity coefficient to be used in a 2D model for heat transfer simulation; moreover the data on the syngas composition have been used to test the reliability of a thermo chemical equilibrium model previously developed. The agreement between the output of the equilibrium model and the experimental data is not satisfying. The main problems are the prediction of the residual solid carbon phase and the methane estimation. It is known that the methane prediction it is a difficult task, because it is mainly formed by tars cracking, and thus it is not an equilibrium compound. Several authors have already faced the problem of methane estimation modifying the model with different approaches. In this work, the experimental data have been used to tune up the model, considering the residual solid carbon formed by means of the definition of a parameter called “carbon conversion efficiency†. The accuracy between the thermodynamic equilibrium model and the experimental values significantly improves if the percentage of solid phase is considered. A second modification has been introduced to take into account the moles of carbon and hydrogen which contribute to the methane formation. A better agreement between the experimental results and the output of the modified model has been observed. The experimental campaign shows that steam gasification represents an interesting pathway for the biomass utilization, because it leads to a high quality effluent gas, suitable for feeding solid oxide fuel cells. The proposed modified equilibrium model seems to be a useful engineering tool, as the syngas composition measured is not so far from the thermodynamic predictions.

The subject of this thesis is the use of BECs for atom interferometry. The standard way atom interferometry is today performed is by interrogating free falling samples of atoms. The employed samples are cold (but not condensed) to have high coherence, and dilute, not to interact significantly with each other. This technique represents nowadays an almost mature field of research in which the achievable interferometric sensitivity is bounded by the atomic shot noise. Until a few years ago the employment of BECs in such devices was strongly limited by the effect of the interactions between the condensed atoms. This obstacle is today removable exploiting interaction tuning techniques. The use of BECs would be advantageous for atom interferometry inasmuch they represents the matter analogue of the optical laser providing the maximum coherence allowed by quantum mechanics. Moreover, non-linear dynamic can be exploited in order to prepare entangled states of the system. The realization of entangled samples can lead to sub-shot noise sensitivity of the interferometers. At today very nice proof-of-principle experiments have been realized in this direction but a competitive device is still missing. This thesis work is inserted in a long term project whose goal is the realization of such a device. The basic operational idea of the project starts with the preparation of a BEC in a double well potential. By the effect of strong interactions the atomic system can be driven into an entangled state. Once the entangled state is prepared, interactions can be †switched off†and the interferometric sequence performed. This thesis begins with the description of the apparatus for the production of tunable BECs to be used in the interferometer. We chose to work with 39K atoms because this atomic species presents many convenient Feshabch resonances at easily accessible magnetic field values. The cooling of this particular atomic species presents many difficulties, both for the laser and evaporative cooling processes. For this reason, this was the last alkaline atom to be condensed. Its condensation up to now was only possible by employing sympathetic cooling with another species. In this thesis our solutions to the various cooling issues is reported. In particular we realized sub-Doppler cooling for the first time for this species and we achieved condensation via evaporation in an optical dipole trap taking advantage of a Feshbach resonance. In the last part of this work, are presented original calculations for the effects of thermal fluctuations on the coherence of a BEC in a double well, discussing the interplay between thermal fluctuations and interactions in this system. Estimations and feasibility studies regarding the double well trap to be realized are also reported.

In this work we will face the problem of the vibrational properties of glasses focusing on the origin and nature of the boson peak (BP). This feature is an universal characteristic of glasses and a fingerprint of the presence of disorder. Two samples have been chosen for this study. The first is permanently densified vitreous SiO$_2$. Permanent densification has been exploited to tune the glassy properties focusing on their evolution. The second sample is a silicon-selenium glass whose low sound velocity allows a detailed study of its dynamics by means of neutron inelastic scattering.

In this thesis we address relevant problems of the physics of quantum disordered systems from a numerical and theoretical point of view, with specific attention to the connection of our findings with ultracold atomic gases experiments. We concentrate on two main issues: the interplay between localization and interaction in disordered systems and the problem of localization in correlated random potentials. The first problem is investigated considering the expansion of a weakly interacting Bose gas in a bichromtic optical lattice. We observe that interaction has a destructive effect on the disorder-induced localization and leads to a subdiffusive expansion of the atomic gas. By comparing three characteristic energy scales of the system one can identify three different spreading regimes: weak chaos, strong chaos and self-trapping. The spreading behaviour in these regimes is predicted theoretically and verified numerically. We also interpreted existing experimental data on the basis of our findings and showed that there is a qualitative agreement between our numerical simulations and experiments. The second problem is investigated proposing a new model of correlated disorder that can be implemented experimentally using ultracold dipolar gases. We show that this model is characterized by the presence of both short and long range correlations. We study the localization properties of the model and highlight the role played by short and long range correlations in the determination of those properties. In particular we show that when short-range correlations are dominant, extended states can appear in the spectrum. The effect of long-range correlations is instead to restore localization over the whole spectrum and lead to counterintuitive behaviours of the localization length. More precisely, depending on the localization regime they can enhance or reduce the localization length at the centre of the band.

In this Thesis we will theoretically address some issues concerning the Physics of ultracold Fermi gases, all of them with experimental relevance. The field of ultracold gases, and more recently of ultracold Fermi gases, is gathering a lot of experimental and theoretical interest for two main reasons: the great control on the relevant parameters of the problem and the relative simplicity of the minimal theory which is able to correctly describe the system. Building upon this solid background, ultracold gases provided an ideal laboratory for testing more refined theories and also for addressing fundamental issues of quantum mechanics as well as for simulating more complex physical systems such as those encountered in condensed matter. Even if the effective hamiltonian of ultracold gases can be simple, due to the diluteness of the system and the low temperature, which imply low energy physics, the solution of the quantum mechanic equations governing the state of these systems is not always simple. For the static properties usually mean-field solutions exist or perturbative expansions can be produced in some regimes. However Quantum Monte Carlo (QMC) techniques provide more accurate results especially in the strongly interacting regimes. For confined systems it is possible to use QMC only for a few particles, so that, for large number of particles, a fruitful combined use of Density Functional Theory (DFT) and QMC is necessary. The study of the dynamics of ultracold gases has received little attention with QMC techniques, due to the intrinsic computational difficulty of the many-body problem, so that general hydrodynamic equations are often used for studying the propagation of smoothly varying perturbations. In this Thesis we use QMC techniques for studying the problem of ferromagnetism in repulsive or effectively repulsive ultracold gases without a lattice and the problem of the Bardeen-Cooper-Schrieffer to Bose-Einstein-Condensation (BCS-BEC) crossover in two dimensions. We use DFT in the Local Density Approximation (LDA) for calculating the density profiles of ultracold Fermi gases in harmonic magneto-optical traps, starting from QMC equations of state. We study the propagation of first and second sound in ultracold Fermi gases in cylindrical geometry, using the hydrodynamic equations of superfluids.

Si presenta in questa tesi una serie di progetti didattici e divulgativi a tema energetica svolti nel corso del dottorato dal candidato. Trova spazio la presentazione di un'indagine originale che ha coinvolto 730 cittadini e volta alla comprensione di quale sia la percezione comune circa alcune tematiche di carattere energetico di estrema attualità. Sono, in seguito, presentati dei progetti didattici che hanno coinvolto scolaresche di scuole primarie e secondarie di primo e secondo grado. Lo scritto, infine, termina con la presentazione di un progetto di start Up accedemica volto alla divulgazione scientifica.

GIXRF (Grazing incidence X-Ray Fluorescence) is an analytical technique with high potential in the study of depth profiles and in the characterization of thin layered structures. To extract information from a GIXRF measurement and determine the layer composition it is necessary to compare the experimental data with simulation. However at the moment this thesis has been written, there is no software widely recognized from the scientific community as the reference software for the analysis. For this reason this work of thesis deals with the development of an analytical software and its application to several case studies. A program called GIMPy is presented. The program is capable to perform simulations of the expected GIXRF signal from a given model, but also of the expected fluorescence signal at high angle of incidence and the reflectivity (XRR). The use of a programming language like Python makes the library extremely portable, easily extendible and flexible thanks to its object oriented syntax and scripting capabilities. GIMPy bases the modelling of the electric field propagation inside the sample and the expected fluorescence from the theoretical description found in literature. Moreover a series of methods were developed to account for the effect of the instrumental set-up geometry, the detector response, indirect excitation and primary beam shape and energy composition. A round-robin related to GIXRF comparison with several institutes developing an analytical software has been organised. The comparison showed a good agreement between the results obtained with GIMPy and the other programs. GIXRF has then been applied to the characterisation of several systems. A combined XRR and GIXRF analysis of multi-layered transparent and conductive oxide films (TCO) of technological interest resulted in a nondestructive and precise characterization of their structures. Measurements were performed at the ESRF synchrotron facility and in the laboratory using a Cu tube as source. Combining the measurements performed with dif- ferent instrumental set-ups the effectiveness of the combined XRR-GIXRFapproach, that has proved already effective in the past, has been further shown. It has been possible to evidence the existence of a thin inter dif- fusion profile induced by annealing the samples, showing a sensitivity to structural changes in the depth of 0.5-1 nm. GIXRF measurements performed on Sn implants in Ge provided information about the total dose retained by the sample after an implantation process. Synchrotron tunable excitation energy was extremely valuable for the fluorescence analysis.The two different modelling strategies used for data fitting, one using a SIMS profile as an input the other an analytical description of the depth profile, and returned values close to the one obtained with other techniques. A new technology based on the deposition of ALD coatings for the preservation of cultural heritage object has been characterised with XRR and GIXRF. The XRR measurements were effective in revealing the deterioration of the coatings after the effect of an accelerated ageing process. Moreover the analysis of GIXRF also revealed the formation of nano-particles at the top of the surface, and allowed the characterisation of their size and composition. The last chapter shows some theoretical calculations investigating GIXRF potential in the size and chemical characterisation of nano-particles. It is shown how the experimental setup and the sample preparation can influ- ence the outcome of the measurement. The theoretical calculations are also reinforced by the result obtained on some preliminary experiments on Gold nano-particles.

A study of methods in few-body nuclear physics is presented, in particular for the study of the photodisintegration cross section of 3He at low energies, and for the determination of phase shifts in low-energy three-body scattering. A possible extension of the methods considered to the study of a five-body problem is investigated.

Abstract There is a growing concern related to increasing energy requirement and greenhouse gas emissions. Hydrogen gas is recognised as a desirable clean fuel and may be a sustainable solution. Hydrogen gas can be directly used as an anodic fuel for Proton Exchange Membrane Fuel Cell that converts chemical energy of hydrogen into electrical energy with no environmentally harmful by-products. Chemical hydrides with high hydrogen storage capacity in terms of gravimetric and volumetric efficiencies are the most promising candidates to supply pure hydrogen at room temperature. Among them, Sodium borohydride (SBH) and Ammonia borane (AB) have drawn a lot of interest as they are stable, non-flammable, nontoxic, and have a high hydrogen storage capability. Large amount of pure hydrogen gas is released during the hydrolysis of these chemical hydrides in presence of certain catalysts. The by-products are non-toxic, environmentally safe and can be recycled. Noble catalysts like Pt and Pd, used in the past to enhance the hydrogen production rate, do not seem to be viable for industrial application considering their cost and availability. Co and Ni borides are considered as good candidates for catalyzed hydrolysis owing to their good catalytic activity, low cost and effortlessly synthesis. Transition metals with varying (metal)/(Co + metal) molar ratio were doped in Co-B catalyst and the effect of metal doping on surface morphology, electronic interaction, and catalytic efficiency of the alloy catalyst powder on hydrogen production by hydrolysis of SBH and AB were studied. On the basis of characterization results, the role of each metal species, involved in hydrolysis and enhanced catalytic performance is discussed. The stability, reusability, and durability of these catalysts have also been investigated. Nanoparticle-assembled Co-B-P thin films on Ni foam (by electroless deposition), along with supported and unsupported Co-B nanoparticles over carbon films were synthesized by Pulsed Laser Deposition and studied for catalytic hydrolysis.