Mechanical Characterization of Cement Composites Reinforced with Fiberglass, Carbon Nanotubes or Glass Reinforced Plastic (GRP) at High Strain Rates

Advanced researches on concrete are directed toward investigating the behavior of reinforced concrete structures in severe conditions such as those promoted by impact loads. Some particular structures (protective shelters, nuclear reactor containment, offshore structures, military structures, chemical or Energy production plant) may be subjected to loading at very high rate of stress or strain caused by impact of missiles or flying objects, also by vehicle collisions or impulses due to explosions and earthquakes. Resistance to impact loads is guaranteed by using cementitious materials having both high strength and ductility. In order to improve ductility cementitious mortars with Glass Reinforced Plastics (GRP) replacing partially the natural sand were manufactured. Moreover, glass fiber (GF) reinforced mortars were produced to enhance toughness. For this scope two types of glass fibers were used different in length and diameter. Since the use of GRP and GF don’t produce any increase in strength of the mortars Carbon Nanotubes were added in the cement matrix to enhance tensile strength of the cementitious composite. Flexural, compressive and Hopkinson bar tests were carried out to evaluate the role of the different materials used. Replacing partially the natural sand with Glass Reinforced Plastics (GRP), compressive and flexural strength decrease (about 20%) with respect those of the reference mortar both on static and dynamic condition as a consequence of an anomalous air entrapment. Adding glass fibers (GF), GRP or/and Carbon Nanotubes (CNTs) no substantial improvement in terms of mechanical properties under static condition was occurred. The Dynamic Increase Factor of the reference mortar was higher than that of the reinforced mixtures, but fracture energy was lower. In particular, combined addition of carbon nanotubes and GRP determines an increase in the energy fracture. The higher the carbon nanotubes content, the higher both fracture energy and tensile strength because nanoparticles oppose to wave and crack propagation, increasing the high strain rate strength. GRP and CNTs reinforced mortars need more fracture energy to failure at 150 s-1 strain rate

Tucidide, Pericle e l’oracolo sulla peste, fra Omero ed Esiodo

Nel secondo libro delle Storie, Tucidide descrive il clima di incertezza e sospetto che era sorto nella città all’inizio della Guerra del Peloponneso, a seguito della diffusione dell’epidemia di peste. In particolare, circolava un oracolo riguardante λιμός (fame) o λοιμός (peste). Questo lavoro esplora la possibilità che Omero e Esiodo siano stati le fonti per la creazione di questo oracolo, suggerendo critiche verso Pericle e la guerra.

Virgilio, Licofrone, e la tradizione su Alessandro Magno

Le immagini di Elena e Menelao, gi\ue0 impiegate per Alessandro, attraverso la storiografia e la poesia ellenistica arrivano alla propaganda augustea rintracciabile in Virgili

Siracusa e il Diomede adriatico

Several Greek and Latin sources provide a link between Dionysius I of Syracuse, the mythical hero Diomedes, and the Adriatic cities. This reflects Dionysius’ colonizing efforts in that area, though the lack of archaeological evidence proves that his success did not last for long

Innovative Caciocavallo cheeses made from a mixture of cow milk with ewe or goat milk.

This study assessed and compared the physicochemical, microbiological, and sensorial characteristics of Caciocavallo cheeses, made from cow milk and a mixture of cow with ewe or goat milk, during ripening. Different cheese-making trials were carried out on an industrial scale following the standard procedure of pasta filata cheeses, with some modifications. The percentage of the different added milk to cow milk influenced compositional and nutritional characteristics of the innovative products, leading to a satisfactory microbiological and sensorial quality