0000000000161930
AUTHOR
L. Calabrese
Electroplated Ni/Ni-Co multilayer coatings for higher corrosion-erosion resistance
Erosion-corrosion behaviour of hierarchical structured hydrophobic nickel-cobalt coating, obtained by electrodeposition, was assessed. In situ electrochemical measurements were carried out to study the corrosion resistance and stability during erosion tests. The electrochemical behaviour was related to surface hydrophobicity and its hierarchical structure nature as well as its modification. The pure Ni showed the lowest erosion-corrosion resistance. A smoothing of the hierarchical structure and thus a reduction the hydrophobicity was highlighted. On the other hand, Ni-Co coating even if associated to a lower electrochemical stability showed a more stable hierarchical structure also at high …
Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle
The main goal of this paper is the evaluation of the performances reversibility of hybrid composites when they are dried after being aged in salt-fog environment. To this aim, epoxy composites reinforced with flax and glass fabrics respectively in the internal and external laminae were at first exposed to salt-fog (i.e., identified as wet phase) and then stored in controlled conditions (i.e., identified as dry phase). The flexural properties evolution of these composites as well as their water uptake and contact angle were monitored at varying time of both phases. The flexural strength and modulus of hybrid composites is 23.4% (17.9%) and 15.5% (12.9%) lower than unaged ones after 30 (15) d…
“Me lo offre un caffè?”: Una ricerca qualitativa sulla ‘collusione di strada’ a Palermo [“Would you offer me a coffee?”: A qualitative research on ‘street collusion’ in Palermo].
Il presente lavoro si propone come studio pilota sulla collusione in terre di mafia. I suoi oggetti di interesse sono Palermo e i “suoi” posteggiatori “abusivi”, figure oggi aggrovigliate al panorama geo-politico della città di cui parlano le strade, gli accadimenti mediatici e la cronaca giudiziaria del capoluogo siciliano. Ci siamo in tal senso chiesti: chi sono questi soggetti sociali? E quali sono le motivazioni della loro presenza ipertrofica in una città come Palermo? Grazie ai dati raccolti attraverso 21 “interviste da strada”, possiamo affermare che il problema è complesso e, come afferma Leoluca Orlando, riguarda posteggiatori e posteggianti, in uno stretto intreccio di collusioni …
Durability of flax-basalt hybrid composites for marine applications
The aim of the present work is to evaluate the influence of external layers of mat basalt on the durability behaviour and performances of flax/epoxy laminates. To this scope, long-term aging tests were performed to evaluate the durability of the two different laminates in critical environmental conditions. In particular, Flax composites were constituted by ten layers of bidirectional flax fabric whereas hybrid laminates (i.e. Flax-Basalt) were produced by replacing four external layers of bidirectional flax with four layers of basalt mat. Both laminates had a total average thickness equal to 3 mm. The samples were exposed to critical environmental conditions following the ASTM B 117 standar…
Bearing failure prediction: an experimental versus numerical approach
An experimental investigation on performances recovery of glass fiber reinforced composites exposed to a salt-fog/dry cycle
The main goal of this paper is the evaluation of the properties reversibility of glass fiber reinforced polymers (GFRPs) under discontinuous exposure to aggressive environmental conditions, typical of marine applications. To this aim, the GFRP manufactured through vacuum infusion process has been initially aged in humid conditions (i.e., exposure to salt-fog at 35 ◦C) for 15 and 30 days and then stored under controlled dry conditions (i.e., 50% R.H. and 23 ◦C) for times varying between 0 and 21 days. In order to evaluate the recover capability of this material, its water uptake has been monitored along the quasi-static flexural properties during the entire humid/dry cycle. Moreover, both 3D…