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A wire shaped coaxial photovoltaic solar cell comprising: a conductive core wire shaped support (401), a nanostructured semiconductor scaffold layer (402), one or more successive perovskite layers (403), an optionally provided hole transporting material layer (404), an outer conductor layer (405), an outer protective layer (406), characterized in that said outer conductor layer (405) comprises dispersed nanoparticles and said perovskite layers (403) are composed identically or wherein two or more of said layers have a different molecular structure and/or composition. The invention also relates to methods and apparatus for the fabrication of said wire shaped coaxial photovoltaic solar cell.

Il lavoro presentato in questa tesi è basato principalmente sullo sfruttamento dei processi termochimici in presenza di acqua supercritica per lo smaltimento dei rifiuti. Dipendentemente dalla tipologia di questi ultimi è possibile utilizzare processi diversi per scopi diversi. Nell’ottica di una completa distruzione delle componenti inquinanti presenti nel refluo è stato preso in considerazione un trattamento di ossidazione in acqua supercritica (SCWO); se invece l’obiettivo è quello di valorizzare uno scarto è possibile sfruttare il processo di gassificazione in acqua supercritica (SCWG). Dopo una breve introduzione per inquadrare il problema dei rifiuti con gli attuali metodi di trattamento e classificare i vari processi termochimici per il loro smaltimento, verranno analizzati in dettaglio i due processi sfruttati nei sistemi utilizzati per le prove sperimentali e quelli progettati nell’ottica di uno scale-up industriale. Su scala di laboratorio sono stati utilizzati dei reattori con volumi ridotti all’interno di configurazioni create appositamente per risultare compatibili fra loro e modificabili in funzione delle necessità e del miglioramento delle prestazioni. Le prove sperimentali sono state effettuate su percolato di discarica con l’obiettivo di sviluppare un impianto pilota per il suo trattamento direttamente nel centro di raccolta in cui viene prodotto. L’esperienza maturata ha permesso di scegliere le configurazioni ottimali per un trattamento ossidativo efficiente e sostenibile mediante l’utilizzo di acqua supercritica. Lo studio di progettazione è affiancato da una preliminare analisi del ciclo di vita, relativa ad un impianto pilota sperimentale, al fine di porre le basi per una più completa valutazione da redigere in caso di futuri sviluppi. La possibilità di valorizzare i rifiuti è stata anche studiata utilizzando un innovativo reattore combinato brevettato da Archimede s.r.l. in collaborazione con il gruppo di ricerca di Impianti Chimici e Biochimici dell’Università degli studi di Palermo. In esso vengono integrati sinergicamente i processi di ossidazione e gassificazione in acqua supercritica. È stato quindi progettato e costruito un sistema per effettuare delle prove sperimentali su scala di laboratorio. Nel capitolo finale verrà esposto un uso alternativo dei processi ossidativi approfondito durante il periodo di studio presso il Politecnico Federale di Zurigo. La generazione di calore è sfruttabile nei sistemi di perforazione del suolo mediante il fenomeno di spallazione termica associato alla convenzionale metodologia meccanica. Si sono quindi analizzate le condizioni necessarie e correlate all’utilizzo di combustibile e comburente liquidi per agevolarne il trasporto all’interno dei sistemi di perforazione. Sono state quindi selezionate le due migliori proposte ed effettuati dei test sperimentali.

In this work, municipal wastewater was treated with microalgal/activated sludge consortia. We aimed at obtaining a positive interaction between the microalgae and the heterotrophic bacteria and identifying the best combination for bioremediation purposes. A strain of Chlorella sp CW2 employed in this work was isolated from AS and molecularly characterised in this work for the first time. This strain and another previously isolated strain (Chlorella sp Pozzillo) were inoculated alone and in combination with AS in different ratios in wastewaters. Microalgae/activated sludge growth curves were obtained by using a UV–vis spectrophotometer and a fluorimeter to distinguish the contribution of the photosynthetic microorganisms to the total growth. The effectiveness for the bioremediation of municipal wastewaters was evaluated by measuring the COD, the total nitrogen and total phosphorous content at the end of batch cultivations. Overall, the best abatement was achieved by the microalga Chlorella sp CW2 inoculated with activated sludge in the ratios 1:2 and 2:1, with a decrease of 81.39 % ± 0.56, 86.12 % ± 0.43, 82.89 % ± 2.66 and 82.5 % ± 0.83, 72.66 % ± 0,46, 97.15 % ± 0.44 of COD, total nitrogen and total phosphorous, respectively. Finally, the residual biomass, constituted by a sludge enriched in microalgae, was analysed for its content in carbohydrates, lipids and fatty acid in order to suggest the best application for its valorisation. Considering the final composition of the obtained biomass and its remediation potential, the most promising sample may be the microalga Chlorella sp CW2 inoculated with activated sludge in the ratio 1:5.

The interest in the process industry on unbaffled stirred tanks has greatly expanded in the last years because they may bring about significant advantages in a number of applications, including biochemical, food and pharmaceutical processes where the presence of baffles is undesirable for several reasons. Despite their application potential, unbaffled vessels still lack fundamental information, due to the fact that only recently their capabilities have started being dug out. The lack of information on scale up effects is possibly the main reason hindering practical applications. In this work the influence of vessel size and liquid viscosity on the mass transfer performance in unbaffled stirred vessels, is investigated. As regards the first issue (scale-up) quite surprisingly results show that comparable mass transfer coefficients may be obtained in larger vessels, for a given power input per unit volume, with typical kLa values up to 2 × 10−3 s−1 in ungassed conditions and of 2 × 10−2 s−1 in gassed conditions. This is opposite to expectations based on the fact that the exchange surface in subcritical conditions only grows with D2 while volume grows with D3. Notably, the same result is obtained at an increased liquid viscosity (a feature often exhibited by biological cultivation broths) and confirms that unbaffled stirred tanks should be regarded as a strong candidate for industrial applications. Finally, also at the larger scale, in the super-critical regime unbaffled tanks are found to provide a performance comparable with that of standard (baffled & sparged) stirred tanks, hence resulting in a viable alternative to baffled tanks for all gas–liquid processes and bio-processes.

The aim of this work is setting up the conditions of an “iso-actinic” photobioreactor that is a photoreactor for the cultivation of microalgae in which the local volumetric rate of photon absorption (LVRPA), can be considered uniform to a good extent. We describe the composition of this cheap photoreactor and how we made it. The system is driven by an Arduino platform that makes it possible to control light intensity as well as light-dark cycles. Preliminary results obtained by growing Nannochloropsis gaditana, a microalga famous for its fat content, in this innovative reactor are presented. We finally observed how microalgae responds to flashing light irradiation.

Flysch is a sedimentary rock consisting of a rhythmic alternation of hard (limestone, sandstone, siltstone) and weak (marl, mudstone, claystone) layers. Because of the presence of layers with different physical properties, the mechanical characterization of heterogeneous rock masses such as flysch is a real challenge. Different methods have been proposed in the literature to characterize flysch, combining empirical classification indexes with laboratory tests. Most of these methods, however, were specifically designed for tunneling and underground excavations, and their applicability to slope stability problems is not yet fully investigated. In this study, we analyze a large landslide in a cretaceous flysch rock in order to compare the mobilized strength at failure with those predicted by the modified GSI method (Marinos and Hoek, 2001). The landslide occurred in the Savena River basin (Northern Apennines of Italy) on April 6, 2013, with a volume of about 3 million m3. Soon after the failure, geological, geotechnical, and geophysical investigations were carried out to detect the failure mechanism and define the landslide geometry. Back analyses of the failed slope were performed using both limit equilibrium and finite difference methods to estimate the in situ strength of the flysch. The results show that the mobilized rock mass cohesion is very low (c ' ≈ 20 ÷ 40 kPa) and that the modified GSI method can predict the in situ strength only assuming a disturbance factor D = 1. Moreover, the analysis shows that the linearization criteria proposed in literature to compute the equivalent Mohr-Coulomb parameters remarkably overestimate the rock mass strength.

The possibility to rapidly deploy a continuous monitoring system in and around an active landslide during an emergency is crucial in order to gather information for hazard and risk scenarios updates. This paper deals with the use of an optimized portable and self-powered array of continuous GPS receivers that has been used for rapid deployment in several landslides during 2013 and 2014 emergency events in Emilia Romagna. In order to optimize the array of GPS receivers, so to make it a sort of plug-and-play system that can be operative in a few hours only and provide data in near-real time,, several technical and logistic issues had to be pre-evaluated and solved in the configuration of the system. These issues are illustrated in the short note together with some of the results obtained in the monitored sites.

Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for its morphological and physicochemical properties, disclosing the formation of a eumelanin-like coating, as confirmed by UV&ndash, vis and electron paramagnetic resonance (EPR) spectroscopy.