0000000000134430
AUTHOR
R. Masi
Cavezzo, the first Italian meteorite recovered by the PRISMA fireball network. Orbit, trajectory, and strewn-field
ABSTRACT Two meteorite pieces have been recovered in Italy, near the town of Cavezzo (Modena), on 2020 January 4th. The associated fireball was observed on the evening of New Year’s Day 2020 by eight all-sky cameras of the PRISMA fireball network, a partner of FRIPON. The computed trajectory had an inclination angle of approximately 68° and a velocity at infinity of 12.8 km s−1. Together with the relatively low terminal height, estimated as 21.5 km, those values were indicating the significant possibility of a meteorite dropping event, as additionally confirmed by the non-zero residual total mass. The strewn-field was computed taking into account the presence of two bright light flashes, re…
A photoelectrochemical investigation of conversion coatings on Mg substrates
Abstract The structure, morphology and composition of conversion coatings grown in stannate bath on pure Mg were studied using potential–time, polarization curves, X-ray diffraction, scanning electron microscopy and photocurrent spectroscopy. The coating is manly constituted by crystalline magnesium–tin hydroxide, whose morphology and distribution depends on the conversion bath composition and temperature. The photoelectrochemical investigation allowed to estimate the band gap value of MgSn(OH) 6 and flat band potential. A sketch of the metal/passive film/electrolyte junction formed during conversion on the metal substrate is reported to account for the overall photoelectrochemical behaviou…
Nanoporous alumina membranes filled with solid acid for thin film fuel cells at intermediate temperatures
Thin film fuel cells have been fabricated by impregnation of inorganic porous membranes with inorganic proton conductor. Anodic alumina membranes (50 μm thick and pore diameter of 200 nm), filled with CsHSO4 salt have been used as protonic conductor in a hydrogen-oxygen fuel cell working between 423 and 443 K in dry atmosphere. Polarization curves at 433 K showing ohmic control with open circuit values near 0.8 V and short circuit current around 8 mA cm−2 have been obtained. Possible causes of degradation as well as alternative routes to overcome some of the problems encountered with this approach will be reported. Keywords: Solid acid, Anodic alumina membranes, Pore filling, Thin film fuel…
Influence of initial treatments of aluminium on the morphological features of electrochemically formed alumina membranes
Abstract The fabrication of alumina membranes by electrochemical oxidation of annealed aluminium was investigated. Porous layers were grown in 0.4 M H3PO4 at −1 and 5 °C at different anodising times. The morphology of the outer surface was found to be dependent on temperature and charge density, with both determining the extent of chemical dissolution of the anodic oxide. The inner-surface morphology was found to depend on the applied voltage only. The chemical dissolution rate of anodic oxide grown on annealed aluminium was found to be lower than that formed on unannealed aluminium under otherwise identical conditions. Such a difference in behaviour is explained in terms of a higher finish…