Applicazione di una metodologia LCA all'impiego di biomasse legnose a fini energetici: un confronto tra la produzione di energia termica da cippato e da pellet

Con questo studio si è volto effettuare un confronto tra la generazione di energia termica a partire da cippato e da pellet, con particolare riferimento agli aspetti di carattere ambientale ed economico conseguenti la produzione delle due differenti tipologie di combustibile. In particolare, si sono ipotizzate due filire, una di produzione del cippato, una del pellet, e per ciascuna di esse si è condotta un'Analisi del Ciclo di Vita, allo scopo di mettere in luce, da un lato le fasi del processo maggiormente critiche, dall'altro gli impatti sulla salute umana, sugli ecosistemi, sul consumo di energia e risorse. Quest'analisi si è tradotta in un confronto degli impatti generati dalle due filiere al fine di valutare a quale delle due corrisponda il minore. E' stato infine effettuato un breve accenno di valutazione economica per stimare quale tipologia di impianto, a cippato o a pellet, a parità di energia prodotta, risulti più conveniente.

Studies of the atmospheric muon flux with the ANTARES detector

The thesis main topic is the determination of the vertical component of the atmospheric muon flux as a function of the sea depth at the ANTARES site. ANTARES is a Cherenkov neutrino telescope placed at 2500m depth in the Mediterranean Sea at 40 km from the southern cost of France. In order to retrieve back the physical flux from the experimental data a deconvolution algorithm has been perform which takes into consideration the trigger inefficiensies and the reconstruction errors on the zenith angle. The obtained results are in good agreement with other ANTARES indipendent analysis.

Procedures of quality control and data analysis of multi-site ground-based observations for the absolute flux calibration of Gaia

The Gaia space mission is a major project for the European astronomical community. As challenging as it is, the processing and analysis of the huge data-flow incoming from Gaia is the subject of thorough study and preparatory work by the DPAC (Data Processing and Analysis Consortium), in charge of all aspects of the Gaia data reduction. This PhD Thesis was carried out in the framework of the DPAC, within the team based in Bologna. The task of the Bologna team is to define the calibration model and to build a grid of spectro-photometric standard stars (SPSS) suitable for the absolute flux calibration of the Gaia G-band photometry and the BP/RP spectrophotometry. Such a flux calibration can be performed by repeatedly observing each SPSS during the life-time of the Gaia mission and by comparing the observed Gaia spectra to the spectra obtained by our ground-based observations. Due to both the different observing sites involved and the huge amount of frames expected (≃100000), it is essential to maintain the maximum homogeneity in data quality, acquisition and treatment, and a particular care has to be used to test the capabilities of each telescope/instrument combination (through the “instrument familiarization plan”), to devise methods to keep under control, and eventually to correct for, the typical instrumental effects that can affect the high precision required for the Gaia SPSS grid (a few % with respect to Vega). I contributed to the ground-based survey of Gaia SPSS in many respects: with the observations, the instrument familiarization plan, the data reduction and analysis activities (both photometry and spectroscopy), and to the maintenance of the data archives. However, the field I was personally responsible for was photometry and in particular relative photometry for the production of short-term light curves. In this context I defined and tested a semi-automated pipeline which allows for the pre-reduction of imaging SPSS data and the production of aperture photometry catalogues ready to be used for further analysis. A series of semi-automated quality control criteria are included in the pipeline at various levels, from pre-reduction, to aperture photometry, to light curves production and analysis.

Measurement of the muon-induced neutron flux at LNGS with the LVD experiment

In this thesis we describe in detail the Monte Carlo simulation (LVDG4) built to interpret the experimental data collected by LVD and to measure the muon-induced neutron yield in iron and liquid scintillator. A full Monte Carlo simulation, based on the Geant4 (v 9.3) toolkit, has been developed and validation tests have been performed. We used the LVDG4 to determine the active vetoing and the shielding power of LVD. The idea was to evaluate the feasibility to host a dark matter detector in the most internal part, called Core Facility (LVD-CF). The first conclusion is that LVD is a good moderator, but the iron supporting structure produce a great number of neutrons near the core. The second conclusions is that if LVD is used as an active veto for muons, the neutron flux in the LVD-CF is reduced by a factor 50, of the same order of magnitude of the neutron flux in the deepest laboratory of the world, Sudbury. Finally, the muon-induced neutron yield has been measured. In liquid scintillator we found $(3.2 \pm 0.2) \times 10^{-4}$ n/g/cm$^2$, in agreement with previous measurements performed at different depths and with the general trend predicted by theoretical calculations and Monte Carlo simulations. Moreover we present the first measurement, in our knowledge, of the neutron yield in iron: $(1.9 \pm 0.1) \times 10^{-3}$ n/g/cm$^2$. That measurement provides an important check for the MC of neutron production in heavy materials that are often used as shield in low background experiments.

Influence of nitrogen and soil physical characteristics on belowground carbon flux dynamics of woody plants

At ecosystem level soil respiration (Rs) represents the largest carbon (C) flux after gross primary productivity, being mainly generated by root respiration (autotrophic respiration, Ra) and soil microbial respiration (heterotrophic respiration, Rh). In the case of terrestrial ecosystems, soils contain the largest C-pool, storing twice the amount of C contained in plant biomass. Soil organic matter (SOM), representing the main C storage in soil, is decomposed by soil microbial community. This process produces CO2 which is mainly released as Rh. It is thus relevant to understand how microbial activity is influenced by environmental factors like soil temperature, soil moisture and nutrient availability, since part of the CO2 produced by Rh, directly increases atmospheric CO2 concentration and therefore affects the phenomenon of climate change. Among terrestrial ecosystems, agricultural fields have traditionally been considered as sources of atmospheric CO2. In agricultural ecosystems, in particular apple orchards, I identified the role of root density, soil temperature, soil moisture and nitrogen (N) availability on Rs and on its two components, Ra and Rh. To do so I applied different techniques to separate Rs in its two components, the ”regression technique” and the “trenching technique”. I also studied the response of Ra to different levels of N availability, distributed either in a uniform or localized way, in the case of Populus tremuloides trees. The results showed that Rs is mainly driven by soil temperature, to which it is positively correlated, that high levels of soil moisture have inhibiting effects, and that N has a negligible influence on total Rs, as well as on Ra. Further I found a negative response of Rh to high N availability, suggesting that microbial decomposition processes in the soil are inhibited by the presence of N. The contribution of Ra to Rs was of 37% on average.

Characterization of new molecular targets involved in iodide flux in the thyroid gland: the anoctamins

Iodide transport is necessary for the synthesis of thyroid hormones following accumulation in the follicular lumen out of thyroid cells, via channels unknown with the exception of pendrin. According to our hypothesis, TMEM16A could be the main molecular identity of the channel mediating iodide efflux in the thyroid gland. TMEM16A is the prior candidate for calcium-activated chloride conductance (CaCC). TMEM16A belongs to the TMEM16/anoctamin family comprising ten members (TMEM16A-K). Higher affinity of TMEM16A for iodide and predicted expression in the thyroid gland suggest its mediation of iodide efflux. The aim of this project was to identify the role of TMEM16A in iodide transport in the thyroid gland, by characterizing its molecular expression and functional properties. We demonstrated that TMEM16F, H, K transcripts are expressed in FRTL-5 thyroid cells, as well as TMEM16A, which is TSH-independent. Tumor tissue from human thyroid maintains TMEM16A expression. Functional in vivo experiments in FRTL-5, stably expressing YFP-H148Q/I152L fluorescent protein as a biosensor, showed that iodide efflux is stimulated by agonists of purinergic receptors with an order of potency of ATP>UTP>ADP (compatible with an involvement of P2Y purinergic receptors), and by agonists of adrenergic receptors (epinephrine, norepinephrine and phenylephrine). Iodide efflux was blocked by α-receptor antagonists prazosin and phentolamine, consistent with a role of α1 adrenergic receptors. Iodide efflux was specifically dependent on calcium mobilized from intracellular compartments and induced by the calcium ionophore ionomycin. CaCC blockers suppressed ionomycin-/ATP-/epinephrine-stimulated iodide efflux. Heterologous expression of TMEM16A in CHO K1 cells induced calcium-activated iodide fluxes. All these results support the hypothesis of the involvement of TMEM16A in calcium-dependent iodide efflux induced by receptor agonists in thyroid cells. TMEM16A may represent a new pharmacological target for thyroid cancer therapy, since its blockade may enhance the retention of radioiodide by tumour cells enhancing the efficacy of radioablative therapy.

Studio ed ottimizzazione di una caldaia a pellet ad elevata economia di produzione

Studio ed ottimizzazione di una stufa a pellet ad elevata economia di fabbricazione.

Studio e progettazione di una stufa a pellet in ghisa per il riscaldamento domestico

Studio e progettazione di una stufa a pellet in ghisa per il riscaldamento domestico per generare una potenza termica di 6.5 kW.

Applicazione delle metodologie LCA ed LCC per la valutazione ambientale ed economica della produzione del pellet realizzato tramite scarti agricoli di potature degli uliveti

Nel seguente lavoro è stata sviluppata una analisi ambientale ed economica del ciclo di vita del pellet, realizzato con scarti agricoli dalle potature degli uliveti. L’obiettivo di tale lavoro è dimostrare se effettivamente l’utilizzo del pellet apporti vantaggi sia dal punto di vista ambientale sia da quello economico. In tale progetto si sviluppano quindi un LCA, Life cycle analysis, e un LCC, Life Cycle Cost, secondo gli steps standard suggeriti da tali metodologie. Per effettuare l’analisi del ciclo di vita è stato utilizzato il software Simapro che ha permesso di valutare gli impatti ambientali sulle varie categorie di impatto incluse. In particolare sono stati considerati due metodologie, una midpoint ed una endpoint, ossia l’Ecoindicator 99 e il CML2 baseline 2000. Per le valutazioni finali è stata poi utilizzata la normativa spagnola sugli impatti ambientali, BOE 21/2013 del 9 dicembre, che ci ha permesso di caraterizzare le varie categorie d’impatto facendo emergere quelle più impattate e quelle meno impattate. I risultati finali hanno mostrato che la maggior parte degli impatti sono di tipo compatibile e moderato; pochi, invece, sono gli impatti severi e compatibili, che si riscontrano soprattutto nella categoria d’impatto “Fossil Fuels”. Per quanto riguarda invece l’analisi economica, si è proceduto effettuando una valutazione iniziale fatta su tutto il processo produttivo considerato, poi una valutazione dal punto di vista del produttore attraverso una valutazione dell’investimento ed infine, una valutazione dal punto di vista del cliente finale. Da queste valutazioni è emerso che ciò risulta conveniente dal punto di vista economico non solo per il produttore ma anche per l’utente finale. Per il primo perché dopo i primi due anni di esercizio recupera l’investimento iniziale iniziando ad avere un guadagno; e per il secondo, poiché il prezzo del pellet è inferiore a quello del metano. Quindi, in conclusione, salvo cambiamenti in ambito normativo ed economico, l’utilizzo del pellet realizzato da scarti di potature di uliveti risulta essere una buona soluzione per realizzare energia termica sia dal punto di vista ambientale, essendo il pellet una biomassa il cui ciclo produttivo non impatta severamente sull’ambiente; sia dal punto di vista economico permettendo al produttore introiti nell’arco del breve tempo e favorendo al cliente finale un risparmio di denaro sulla bolletta.

Valutazione del contributo emissivo in condizioni non-stazionarie alle emissioni totali di una stufa a pellet domestica

The aim of this work is to evaluate the emissions of the main pollutants of a pellet stove, by trying to simulate the real use in domestic operations. All the operating phases of this system were considered: ignition, partial load, increase in power, and nominal load. In each phase, quantity and type of some pollutants in emissions were determined: the main pollutant gases (CO, NOx, SO2, H2S and volatile organic compounds (VOCs)), total dust (PM) and its content of polycyclic aromatic hydrocarbons (PAHs), regulated heavy metals (Ni, Cd, As and Pb), main soluble ions and Total Carbon (TC). Results show that emission factors of TSP, CO, and of the main determined pollutants (TC, Cd and PAHs) are higher during ignition phase. In particular, this phase prevalently contributes to PAHs emissions. During increase in power phase, gas and particulate emissions do not appreciably differ from nominal load ones; nevertheless, PAH emission factors are higher than steady state ones, but lower than ignition phase. Moreover, during not-steady state phases, PAH mixture is more toxic than during steady state phases. In conclusion, this study allowed to go deeper in pellet stove environmental impact, by pointing out how the different operating conditions can modify the emissions. These are different from certificated data, which are based exclusively on measurements in steady state conditions.

Studio e ottimizzazione di una stufa a pellet a basso costo

Studio e ottimizzazione di una stufa a pellet a basso costo con CFD.

The contribution of the Finite Volume Point Dilution Method to the determination of solute mass flux in an alluvial aquifer.

Groundwater represents one of the most important resources of the world and it is essential to prevent its pollution and to consider remediation intervention in case of contamination. According to the scientific community the characterization and the management of the contaminated sites have to be performed in terms of contaminant fluxes and considering their spatial and temporal evolution. One of the most suitable approach to determine the spatial distribution of pollutant and to quantify contaminant fluxes in groundwater is using control panels. The determination of contaminant mass flux, requires measurement of contaminant concentration in the moving phase (water) and velocity/flux of the groundwater. In this Master Thesis a new solute flux mass measurement approach, based on an integrated control panel type methodology combined with the Finite Volume Point Dilution Method (FVPDM), for the monitoring of transient groundwater fluxes, is proposed. Moreover a new adsorption passive sampler, which allow to capture the variation of solute concentration with time, is designed. The present work contributes to the development of this approach on three key points. First, the ability of the FVPDM to monitor transient groundwater fluxes was verified during a step drawdown test at the experimental site of Hermalle Sous Argentau (Belgium). The results showed that this method can be used, with optimal results, to follow transient groundwater fluxes. Moreover, it resulted that performing FVPDM, in several piezometers, during a pumping test allows to determine the different flow rates and flow regimes that can occurs in the various parts of an aquifer. The second field test aiming to determine the representativity of a control panel for measuring mass flus in groundwater underlined that wrong evaluations of Darcy fluxes and discharge surfaces can determine an incorrect estimation of mass fluxes and that this technique has to be used with precaution. Thus, a detailed geological and hydrogeological characterization must be conducted, before applying this technique. Finally, the third outcome of this work concerned laboratory experiments. The test conducted on several type of adsorption material (Oasis HLB cartridge, TDS-ORGANOSORB 10 and TDS-ORGANOSORB 10-AA), in order to determine the optimum medium to dimension the passive sampler, highlighted the necessity to find a material with a reversible adsorption tendency to completely satisfy the request of the new passive sampling technique.