Hybrid Hemp Particles as Functional Fillers for the Manufacturing of Hydrophobic and Anti-icing Epoxy Composite Coatings

The development of hydrophobic composite coatings is of great interest for several applications in the aerospace industry. Functionalized microparticles can be obtained from waste fabrics and employed as fillers to prepare sustainable hydrophobic epoxy-based coatings. Following a waste-to-wealth approach, a novel hydrophobic epoxy-based composite including hemp microparticles (HMPs) functionalized with waterglass solution, 3-aminopropyl triethoxysilane, polypropylene-graft-maleic anhydride, and either hexadecyltrimethoxysilane or 1H,1H,2H,2H-perfluorooctyltriethoxysilane is presented. The resulting epoxy coatings based on hydrophobic HMPs were cast on aeronautical carbon fiber-reinforced panels to improve their anti-icing performance. Wettability and anti-icing behavior of the prepared composites were investigated at 25 °C and −30 °C (complete icing time), respectively. Samples cast with the composite coating can achieve up to 30 °C higher water contact angle and doubled icing time than aeronautical panels treated with unfilled epoxy resin. A low content (2 wt %) of tailored HMPs causes an increase of ∼26% in the glass transition temperature of the coatings compared to pristine resin, confirming the good interaction between the hemp filler and epoxy matrix at the interphase. Finally, atomic force microscopy reveals that the HMPs can induce the formation of a hierarchical structure on the surface of casted panels. This rough morphology, combined with the silane activity, allows the preparation of aeronautical substrates with enhanced hydrophobicity, anti-icing capability, and thermal stability

Effects of water sorption on poly(lactic acid)

When in contact with water, poly(lactic acid), PLA, undergoes severe physical changes. Hydrolysis is obviously the most expected and studied one, and it is followed by weight loss. However, other phenomena occur such as opacification and crystallization. Although these phenomena are sometimes reported in the literature, apart from hydrolysis which has been thoroughly studied at several temperatures, the other ones have not been deeply analyzed and their timescales have not been so far determined. This work aims at studying the physical changes induced by water sorption to PLA, by analyzing the modifications taking place in solid samples immersed in water for different times (starting from a few hours) and at temperatures close to the glass transition. The obtained results allow determining the timescales of the different phenomena and thus the possible cause-effect relationship among them. In particular, it is shown that opacity is the first phenomenon to become evident, on a timescale consistent with water sorption, and seems to be due to crazes induced by water. The second phenomenon to become evident is the crystallinity evolution, which is shown to be consistent with a heterogeneous nucleation on the crazes. These two phenomena take place before hydrolysis becomes significant, thus raising doubts about the fact that hydrolysis can be their cause

Potential role of sulfide and ammonia as confounding factors in elutriate toxicity bioassays with early life stages of sea urchins and bivalves

This work reports some considerations on the possible contribution of sulfide and ammonia to the toxicity of elutriate samples of sediments from the Venice lagoon, tested with a battery of bioassays using early life stages of the sea urchin Paracentrotus lividus and the oyster Crassostrea gigas. A comparison of ammonia or sulfide concentration in the test matrix, matrix toxicity, and the sensitivity limit of bioassays for ammonia or sulfide were used in evaluating toxicity data. Results highlighted that sperm cell and embryo toxicity of elutriates were not affected by sulfides. Neither was any direct relationship shown between elutriate toxicity and ammonia concentration. Most elutriates had ammonia concentrations below the sensitivity limit of acute test methods, while the more sensitive subchronic toxicity tests were affected by ammonia interference in some samples. © 2006 Elsevier Inc. All rights reserved

GENOTOXICITY AND BIOCONCENTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND HEAVY METALS IN LEUCISCUS CEPHALUS FROM PESCARA RIVER (ABRUZZO - ITALY): AN INTEGRATED APPROACH

The aim of the present study was to investigate the water quality and the ecosystem health of a segment of Pescara river (Abruzzo-Italy) with the aid of an integrated approach. Sixteen priority polycyclic aromatic hydrocarbons and heavy metals were determinated in water and chub samples in order to calculate the bioconcentration factor. Biochemical, physical and microbiological characterisation were also carried out on water samples. Moreover, real and synergic effects of water pollution on biota were investigated by genotoxicological tests. Water samples were tested by Salmonella mutagenicity assay, whereas micronucleus assay on chub  was used to evaluate environmental genotoxic effects on fish. The characterisation of  water samples did not reveal any relevant contamination of Pescara river, but some analytical results obtained for biota were remarkable. In particular, the comparison between the site downstream from the industrial area of Chieti and the control site showed significant differences in chub micronuclei frequencies

Sala delle Vittorie

Il contributo analizza la decorazione ad affresco della Sala delle Vittorie, ubicata nel Palazzo dei Cavalieri a Pisa, realizzati agli inizi dell'Ottocento, integrandola all'interno del più ampio panorama della cultura figurativa di stampo neoclassico diffusa a Pisa in quegli anni