Hydrogen desorption in Mg(BH4)2-Ca(BH4)2 system

Magnesium borohydride, Mg(BH4)2, and calcium borohydride, Ca(BH4)2, are promising materials for hydrogen storage. Mixtures of different borohydrides have been the subject of numerous researches; however, the whole Mg(BH4)2-Ca(BH4)2 system has not been investigated yet. In this study, the phase stability and the hydrogen desorption were experimentally investigated in the Mg(BH4)2-Ca(BH4)2 system, by means of XRD, ATR-IR, and HP-DSC. Mg(BH4)2 and Ca(BH4)2 are fully immiscible in the solid state. In the mechanical mixtures, thermal decomposition occurs at slightly lower temperatures than for pure compounds. However, they originate products that cannot be identified by XRD, apart from Mg and MgH2. In fact, amorphous phases or mixtures of different poorly crystalline or nanocrystalline phases are formed, leading to a limited reversibility of the system

Impact of the fat dormouse (Glis glis Linnaeus 1766) on hazel orchards in the area of Alta Langa and Belbo, Bormida, Uzzone Valleys (province of Cuneo, Italy): a preliminary assessment of agricultural damage

Ghirardi, M., Tizzani, P., Dematteis, A

Characterization of a New Zinc Fixed-Point Cell for ITS-90 Realization

A new zinc fixed-point cell for the dissemination of International Temperature Scale (ITS-90) was realized at the Italian National Metrological Institute (Istituto Nazionale di Ricerca Metrologica, INRiM). This paper presents the results of its characterization, including fabrication details. In particular, immersion effects and influences of impurities on the freezing point of zinc were studied. The new open-type cell was prepared using a high purity sample, chemically analyzed, and the depression of the fixed-point temperature was calculated using the method of Sum of Individual Estimates (SIE). The new cell presents a smaller freezing point depression compared with the national reference for which the Overall Maximum Estimate (OME) method was applied. This behavior was confirmed also by the direct comparison of the two cells. These results provide confidence on the agreement between the experimental comparison and the SIE/OME evaluation. Finally, the improvement of the new zinc cell is reflected also in a lower uncertainty budget for the fixed-point realization

Realisation of the triple-point of Argon: comparison between two devices

A new cryostat for the realization of the triple-point of the argon (83.8058 K), a defining fixed point of the International Temperature Scale of 1990 (ITS-90), was acquired at Italian National Metrological Institute (INRiM). The new system, manufactured by Fluke, is intended to substitute the current National reference, a model developed at BNM-INM in the 1975. The main difference between the two system is in the way to control the temperature. In the BNM-INM device the temperature is controlled adjusting the pressure of liquid nitrogen bath, in the Fluke system instead, an electrical heater wrapped around the argon cell is used, following cryogenic practice. This paper describes the result of the direct comparison and shows typical phase transitions obtained with the two argon systems. Then, a complete uncertainty budget is evaluated for the new Fluke system and compared with the National standard