Solid State Synthesis of CaMnO3 from CaCO3-MnCO3 Mixtures by Mechanical Energy

Abstract A solid state synthesis of calcium manganite (CaMnO3) is described where equimolecular mixtures CaCO3:MnCO3 have been subjected to mechanical stress (high energy milling) so yielding CaCO3-MnCO3 solid solutions of nanometric particle size. TG measurements have shown that a link exists between milling time, the extent of non-stoichiometry and the milling-induced decomposition of MnCO3 to Mn3O4. A short (2 h) annealing at 850 °C performed on a sample mixture milled for 25 h leads to non-stoichiometric CaMnO3−x. No sure conclusion could be drawn for the stoichiometry of CaMnO3 obtained, under the same annealing conditions, from a mixture milled for longer time (150 h). No synthesis of CaMnO3 could be effected by long (48 h) annealing at 1200 °C of mixtures that had not been subjected to mechanical stress

Reversible hydrogen sorption in the composite made of magnesium borohydride and silica aerogel

Magnesium borohydride Mg(BH4)2 is a promising hydrogen storage material as it releases high hydrogen storage capacity at mild desorption temperatures, but it is still limited by slow hydrogen release kinetics and by the harsh conditions required to re-hydrogenate this compound. In this work, composites made of commercial Mg(BH4)2 and synthesized silica aerogel microparticles were prepared by thermal treatment in hydrogen under 120 bar and 200ºC. As a result, the sorption properties of the hydride are improved: calorimetric measurements show that decomposition temperature is reduced by 60ºC, and the typical 3-step decomposition mechanism of Mg(BH4)2 changes to a single-step mechanism in range of 220-400°C. The kinetics of the first dehydrogenation at 300ºC was two times faster in Mg(BH4)2-SiO2 composites than in the case of bulk γ-Mg(BH4)2. Additionally, the re-hydrogenation of this material at comparatively moderate conditions of 390ºC and 110 bar is presented for the first time, achieving cyclability with a reversible release of hydrogen up to 6wt%. Different amounts of hydrogen were exchanged depending on the temperature of desorption (300ºC or 400ºC) and the presence or absence of silica aerogel. This result indicates that silica aerogel chemically interacts with Mg(BH4)2, acting as an additive, which can result in different hydrogenation-dehydrogenation routes in which different amounts and types of intermediates are formed, influencing the kinetics and the cyclability.2018-07-27Spanish Ministry of Economy and Competitiveness project ENE2014-53459-

Optimal hydrogen storage in sodium substituted lithium fullerides

A relevant improvement in the hydrogen storage capability of lithium fullerides is obtained by the co-intercalation of a small amount of sodium

Le vie di comunicazione nel territorio campano della Media Valle del Volturno tra l’area alifana e quella telesina sino all’età moderna: dalla cartografia storica al GIS / The communication routes in the Campania region of the Media Valle del Volturno between the Alifana and Telesina areas up to the modern age: from historical cartography to GIS

Questo lavoro presenta un’analisi storico-geografica dello sviluppo in età moderna della rete viaria del territorio della media valle del Volturno comprendente le aree alifana e telesina, facente parte dell’attuale regione Campania, posto in un luogo di snodo strategico tra i versanti tirrenico e adriatico. La cartografia storica esistente, opportunamente georeferenziata ed inserita in un sistema informativo geografico (GIS), è stata la fonte principale per la ricostruzione diacronica del sistema viario di quest’area. Dal punto di vista metodologico, si è fatto anche ricorso, quando disponibili, a fonti testuali, come diari di viaggio, itinerari e rapporti, contenenti informazioni su strade, ponti, taverne o altri elementi, ricollegabili a percorsi viari del Medio Volturno. Il tutto con l’obiettivo di proporre una approfondita comprensione delle dinamiche evolutive del territorio in esame, considerata come il punto di partenza di un processo di programmazione e valorizzazione dell’intera area, anche in chiave turistica. Il lavoro si conclude dimostrando ancora una volta che si perpetuano vecchi errori di pianificazione, ossia la costruzione di importanti assi di comunicazione di collegamento tra le aree metropolitane della parte meridionale del paese (ferrovia e superstrada) senza che il territorio attraversato possa aver avuto vantaggi in termini di sviluppo.This work presents an historical-geographical analysis of the development patterns in the modern age of the road network of the middle Volturno valley comprising the Alifana and Telesina area, included in the current Campania region and located in a strategic junction between the Tyrrhenian and Adriatic seas. The existing historical cartography, appropriately georeferenced and inserted in a geographic information system (GIS), was the main source for the diachronic reconstruction of the road system in this area. From a methodological point of view, textual sources were also used, when available, such as travel diaries, itineraries and reports, containing information on roads, bridges, taverns or other elements, which can be connected to road routes in the middle Volturno. All work was accomplished with the aim of proposing an in-depth understanding of the evolutionary dynamics of the territory in question serving as the starting point of a planning and enhancement process of the entire area, including from a tourism point of view. The work concludes by demonstrating once again that previous planning errors are perpetuated, i.e. the construction of important communication axes (railway and expressway) connecting the metropolitan areas of the southern part of the country without having any advantages in terms of development patterns

Le vie di comunicazione nel territorio campano della Media Valle del Volturno tra l’area alifana e quella telesina sino all’età moderna: dalla cartografia storica al GIS

This work presents an historical-geographical analysis of the development patterns in the modern age of the road network of the middle Volturno valley comprising the Alifa na and Telesina area, included in the current Campania region and located in a strategic junction between the Tyrrhenian and Adriatic seas. The existing historical cartography, appropriately georeferenced and inserted in a geographic information system (GIS), was the main source for the diachronic reconstruction of the road system in this area. From a methodological point of view, textual sources were also used, when available, such as travel diaries, itineraries and reports, containing information on roads, bridges, taverns or other elements, which can be connected to road routes in the middle Volturno. All work was accomplished with the aim of proposing an in-depth understanding of the evolutionary dynamics of roads of the territory in question serving as the starting point of a planning and enhancement process of the entire area, including from a tourism point of view. The work concludes by demonstrating once again that previous planning errors are perpetuated, i.e. the construction of important communication axes (railway and expressway) connecting the metropolitan areas of the southern part of the country without having any advantages in terms of development patterns.Questo lavoro presenta un’analisi storico-geografica dello sviluppo in età moderna della rete viaria del territorio della media valle del Volturno comprendente le aree alifana e tele sina, facente parte dell’attuale regione Campania, posto in un luogo di snodo strategico tra i versanti tirrenico e adriatico. La cartografia storica esistente, opportunamente georeferenziata ed inserita in un sistema informativo geografico (GIS), è stata la fonte principale per la ricostruzione diacronica del sistema viario di quest’area. Dal punto di vista metodologico, si è fatto anche ricorso, quando disponibili, a fonti testuali, come diari di viaggio, itinerari e rapporti, contenenti informazioni su strade, ponti, taverne o altri elementi, ricollegabili a percorsi viari del Medio Volturno. Il tutto con l’obiettivo di proporre una approfondita comprensione delle dinamiche evolutive delle vie di comunicazione del territorio in esame, considerata come il punto di partenza di un processo di programmazione e valorizzazione dell’intera area, anche in chiave turistica. Il lavoro si conclude dimostrando ancora una volta che si perpetuano vecchi errori di pianificazione, ossia la costruzione di importanti assi di comunicazione di collegamento tra le aree metropolitane della parte meridionale del paese (ferrovia e superstrada) senza che il territorio attraversato possa aver avuto vantaggi in termini di sviluppo

Web resources for Computer-Aided Instruction: A blended classification scheme

The huge quantity of data, media, applications, and services - in one word, resources - that are accumulating day after day on the Web makes it more and more difficult to search the network in an effective and helpful way. We usually spend a lot of the time trying to "filter out" what we consider "noise" added to the "good information" for which we are looking. Whatever the search domain, this messy and discouraging situation cannot be handled by general search engine, such as Google. We also face similar problems in the instructional domain. In this paper we focus on the need for creating tools that can help classifying and retrieving digital Web resources for Computer-Aided Instruction processes. We propose a strong, but simple and flexible, classification scheme, which can be easily and profitably used by a Web community (of teachers, learners, and others) to create a database of references to digital instructional resources. Our classification scheme uses a blended top-down/bottom-up approach with a Delicious-like annotation and tagging system not fully free, but based upon a controlled and predefined and expandable set of metadata

LA RISCOPERTA DEI CAMMINI DELLA TRANSUMANZA NELL’AREA CAMPANA DEL MATESE. PERCORSI E FILIERE ECONOMICHE

The rediscovery of transhumance routes in the Matese area of Campania. Paths and economic chains. – The Matese mountain complex is part of the southern Apennines chain and currently divides the Campania and Molise regions. Inhabited since the pre-Roman age by Samnite people, throughout histo-ry it has represented a place of transit between the Campania plain and the Adriatic side. With the establishment and regulation of the Regi Trat-turi in the Aragonese era, part of the ancient walkways that crossed the Matese were used by the shepherds of the Campania side to connect with the main Pescasseroli-Candela sheep track that surrounds the mountain complex in the Molise part. Until the 18th century, sheep breeding and the production of woolen cloths represented among the most important items for the economy of the territories located on the Campania side of Matese. Centers such as Piedimonte d'Alife (today Piedimonte Matese), Cerreto Sannita, Cusano and Morcone based their economic well-being on these activities for a long time, so much so that they are considered among the most active centers of the ancient King-dom. The purpose of this study is the rediscovery of this network of paths and of the ancient connected economic chains as a fundamental prerequisite for a development proposal for the area, which is currently experiencing a period of profound economic stagnation with consequent depopulation. The methodology used refers to the analysis of historical documentary and cartographic sources and the GIS will be used for the identification and tracing of these paths

Nanomateriali per stoccaggio di idrogeno in unità mobili

A general overview on nanomaterials for solid state hydrogen storage is presented. The most common preparation and characterization techniques are discussed

Formazione delle ferriti di calcio (Ca2Fe2O5 e CaFe2O4) per reazione allo stato solido in miscele di precursori organici: influenza della attivazione meccanica

The influence of mechanical activation on the solid state synthesis of Ca ferrites starting from organic precursor is studied in detail by thermogravimetric and calorimetric analysis and X-Ray powder diffraction