1,721,026 research outputs found
Unraveling the Effect of Carbon Nanotube Oxidation on Solid-State Decomposition of Ammonia Borane/Carbon Nanotube Composites
Full text linkAmong the routes to perform hydrogen release from ammonia in solid state, the nanoconfinement into a carbonaceous matrix or the use of carbon-supported catalysts for the thermal degradation of ammonia borane (AB) is the most interesting one. Oxidized carbon nanotubes (CNTs) represent a suitable choice for preparing AB mixtures or for anchoring catalysts for dehydrogenation. Nevertheless, literature lacks detailed study about the influence of CNT oxidation degree on the AB degradation/hydrogen release. In this study, we first described in a comprehensive way that the thermal degradation of AB mixed with CNTs by varying the CNT oxidation degree enlightens the degradative routes mainly active in each case. Using highly oxidized CNTs, we observed a decrement of activation energy of the degradative process up to around 53% and the activation/suppression of different pathways based on the amount of oxygen functionalities present in the mixtures. Furthermore, the presence of oxidized CNTs modulated the solid-state reactivity of AB reducing the release of nitrogen/boron species together with hydrogen. These findings lead the way for the design of new hydrogen storage materials
Ristrutturazione del servizio pubblico radiotelevisivo
No full textL'obiettivo di risolvere la questione del pluralismo radiotelevisivo in Italia è statao affrontato dalla legge Maccanico n. 249/1997 attraverso una serie di disposizioni tra loro collegate. Tra queste si annovera quella concernente la non accessibilità alla risorsa pubblicitaria da parte di una delle reti pubbliche, a fronte del passaggio su satellite di una delle emittenti televisive del maggiore detentore privato di concessioni televisive. Attraverso la ricostruzione della giurisprudenza costituzionale e dei precedenti interventi normativi, e considerando la rilevanza europea della questione, sono descritte, criticamente, le prospettive attuative della riforma e della disciplina de qua. Il tempo ha confermato le critiche al tempo mosse
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Istituzione dell'Autorità per le garanzie nelle comunicazioni e norme sui sistemi delle telecomunicazioni e radiotelevisivo. Legge 31 luglio 1997, n. 249 . Sub. art. 3, comma 11.
No full textAnalisi critica del nuovo regime amministrativo previsto per la tv in forma codificata. Analisi nel quadro normativo europeo. Riflessi sul sistema televisivo
Performance study of a thin film cation exchange membrane on carbon electrode for supercapacitor application
Full text linkIn this work we report a green procedure for the infiltration of a SPEEK solution into a porous carbon electrode resulting in a thin-film cation exchange membrane. The electrodes have been investigated by a morphological point of view, showing the formation of a thin coating infiltrated into the porous carbonaceous matrix, while mechanical peeling of a tape demonstrated the adhesion of the proposed layer. The fabricated electrodes have been analyzed by electrochemical measurement. The 3-electrode cyclic voltammetry measurements allowed to verify the voltage window resulting in an improved negative potential, while the electrochemical impedance spectroscopy showed a reduction of the electrical resistance. The SPEEK electrode was used in a supercapacitor and deeply characterized by electrochemical analysis. The reported findings demonstrate for the first time the possibility to exploit a cation exchange material in thin film configuration for supercapacitor application with improved performance of the device and exclusively involving the use of nontoxic reagents
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