Tre note di apertura

Analisi della crtitica di Hayek al totalitarismo nel più ampio contesto del dibattito sul totalitarismo nel Secondo dopoguerr

Il ricordo che trasfigura luoghi ed eventi

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Effect of the embedment of carbon doped nanocomposites in a real matrix on the enhanced photocatalytic activity

Solar light can be used by semiconductor nanocrystals as a free and largely available source of energy to transform air pollutants into non-volatile less harmful chemicals. The efficiency of this process can be enhanced by doping the semiconductor with carbon-based materials, such as graphene. Nevertheless, such an increased activity has been reported (i) for nanocomposite photocatalysts produced on the research laboratory scale, (ii) analyzing their performance as self-standing photocatalysts and not after incorporation into “real” matrixes (e.g. building materials) and (iii) typically using model target pollutants instead of “real” hazardous ones. Here we describe the large-scale preparation of two series of carbon based photocatalysts starting from commercial materials and we demonstrate their superior photocatalytic activity in degrading important air pollutants as nitrogen oxides, compared to undoped photocatalysts. The photocatalytic activity was evaluated by NOx abatement adopting the continuous flow procedure and the apparatus reported in the Italian standard UNI 11,247. Best performing materials were incorporated into two different inorganic matrixes (cement and lime). In both cases, the superior photocatalytic performances were maintained. An improvement up to 42±7% of the photocatalytic activity was measured in the case of a cement sample for a carbon-doped photocatalyst with respect to bare TiO2 . The materials were characterized by UV-Vis spectroscopy, high resolution powder X-ray diffraction (HR-PXRD), high-resolution scanning electron microscopy (HR-SEM) energy-dispersive X-ray spectroscopy (EDS) and micro-Raman

Photocatalytic activity of exfoliated graphite-TiO2_2 nanocomposites

We investigate the photocatalytic performance of composites prepared in a one-step process by liquid-phase exfoliation of graphite in the presence of TiO2 nanoparticles (NPs) at atmospheric pressure and in water, without heating or adding any surfactant, and starting from low-cost commercial reagents. These show enhanced photocatalytic activity, degrading up to 40% more pollutants with respect to the starting TiO2-NPs, in the case of a model dye target, and up to 70% more pollutants in the case of nitrogen oxides. In order to understand the photo-physical mechanisms underlying this enhancement, we investigate the photo-generation of reactive species (trapped holes and electrons) by ultrafast transient absorption spectroscopy. We observe an electron transfer process from TiO2 to the graphite flakes within the first picoseconds of the relaxation dynamics, which causes the decrease of the charge recombination rate, and increases the efficiency of the reactive species photo-production.We acknowledge funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 785219 (GrapheneCore2), EU Neurofibres, ERC Minegrace and Hetero2D, EPSRC Grants EP/509K01711X/1, EP/K017144/1, EP/N010345/1, EP/M507799/5101, and EP/L016087/1

Quali strumenti giuridici statali e regionali per le comunit\ue0 patrimoniali?

The Framework Convention on the Value of Cultural Heritage for Society (Faro Convention, 2005) recognizes a central role to heritage communities in the process of identification, study, interpretation, protection, conservation and presentation of the cultural heritage. As a signatory State of the Convention (signed on 27th February 2013, still waiting for ratification), Italy has in any case to ensure its contribution to the safeguarding of the tangible and intangible cultural heritage by adequate policies. Currently, a State law providing a general regulation of the participation of civil society to the protection and the enhancement of cultural heritage in the Italian legal system has not been adopted yet. Nevertheless, communities, groups and individuals have a wide range of instruments available, which can be drawn by an accurate interpretation of the Constitution and of many State and regional laws. In the long run, the persistent lack of common rules on this subject may be a source of uncertainty, capable of weakening, instead of strengthening, the role of heritage communities, in contrast with the principles of the Faro Convention

Citizens of Europe

Il titolo della collana esprime la volont\ue0 di approfondire i profili legati al processo di integrazione europeo, non ignorandone i risvolti pi\uf9 discutibili e burocratici ma sapendo guardare al di l\ue0 di essi, nella logica che traspare dal gioco di assonanze indicato dal titolo. In questo terzo volume Citizens of Europe, dedicato ai temi delle identit\ue0 e della cittadinanza culturale, viene in rilievo la tensione tra i limiti delle politiche, culturali e di cittadinanza, perseguite dalla UE e l\u2019imporsi progressivo \u2013 malgrado le cupe ombre proiettate dalla drammatica attualit\ue0 \u2013 di una pi\uf9 ampia nozione di \u2018cittadinanza d\u2019Europa\u2019, scandita in particolare da quei recenti strumenti giuridici del Consiglio d\u2019Europa attraverso i quali l\u2019afflato europeo, non imprigionato nelle pastoie dei meccanismi della EU citizenship, si sviluppa pi\uf9 significativamente