Search results for " Materiali"

Improvement of actinorhodin production yield in Streptomyces coelicolor by immobilized-cell cultivations by using PCL- and PLA-based films

2016

Actinomycetes are Gram-positive bacteria producing most of naturally occurring antibiotics (Donadio et al., 2010). At industrial level, antibiotics are produced by submerged fermentations where the actinomycete filamentous morphology negatively affects bioproductivity (van Dissel et al., 2014). Microporous membranes for bacterial cell-immobilization were already proven increasing bioproductivity in Streptomyces coelicolor, that is a model actinomycete producing the blue pigmented actinorhodin (ACT) antibiotic (Scaffaro et al., 2016). To develop an immobilized-cell bioreactor system, different kinds of polycaprolactone (PCL) and polylactic acid (PLA) films were produced by an electrospinning…

Polysaccharide-based supramolecular bicomponent eutectogels as sustainable antioxidant materials

2023

In this work, we obtained supramolecular gels in deep eutectic solvents (DES) from polysaccharides like chitosan and chitosan : cellulose composites. We thoroughly characterized our gels by determining the minimum gelation concentration, as well as their porosity and swelling. We also investigated their mechanical properties by rheology, and morphology by scanning electron measurements. These properties were mainly influenced by the number of hydrogen bond sites on the hydrogen bond donor, (HBD), while FTIR-ATR investigation suggested that, upon gelation, cholinium cations interpose between polysaccharide chains affecting interchain hydrogen bonding. Our gels also exhibited self-healing and…

Characterization of stucco works by means of simultaneous thermal analysis

2008

Environmental degradation of polymers for cultural heritage

2018

Plastic materials are used both for the protection of cultural heritage and as material for artworks. As for other materials, the durability and the maintenance of their initial properties are fundamental for the use of these materials. For the protection of the cultural heritage (particularly for stone artworks) the main important properties are the hydrophobicity, the UV transparency and the water vapour permeability that must be maintained even after a long exposure to the environmental conditions (UV irradiation, rain, temperature variations, etc.). When the polymers are used for the production of an artwork, the most important characteristics are the maintenance of the aesthetical appe…

Caratterizzazione delle vernici utilizzate nella liuteria storica

2009

Mortars and Plasters under the Mosaics and the Wall Paintings of the Roman Villa at Piazza Armerina, Sicily

2010

The Roman Villa at Piazza Armerina in Sicily, built in many successive steps over the 2nd and 3rd centuries A.D., is renowned all over the world for both the wealth and the refinement of its mosaic floors. In February 2007 the Regional Government of Sicily started a restoration project of the whole archaeological site. The systematic survey and study of all decorative elements highlighted the value of wall paintings, which until then were almost unknown except for casual approaches to specific problems of conservation, carried on without any relation to the far and away famous mosaics. This paper shows the results of a physical chemical investigation of the mortars used for both floors and …

Effect of accelerated ageing on the mechanical behaviour of basalt/hemp hybrid composites

2017

The remarkable concerns related to environmental pollution have triggered a lot of studies aimed at decreasing the environmental impact of polymer composites. A possible way to achieve this goal is the replacement of glass fibres with natural ones. In particular, lignocellulosic fibres are of considerable interest because they are renewable resources and are characterized by low cost, low density, thermal and acoustic insulation, biodegradability and recyclability. Despite these favourable attributes, cellulosic fibre reinforced composites do not provide mechanical properties comparable with those of glass fibre composites and, most importantly, their susceptibility to moisture absorption c…

Antimicrobial activity of EVA blown films containing nisin

2009

Il restauro dello "Scheletro in marmi mischi" della Galleria Abatellis: dalla colofonia naturale ai prodotti di sintesi. Sperimentazione di formulati…

2017

Il lavoro qui presentato ha per oggetto il restauro di un frammento di tarsia marmorea rappresentante uno scheletro, probabilmente in origine collocato all’interno di una cripta o facente parte di un cenotafio o di un monumento sepolcrale, custodito all’interno dei depositi della Galleria Interdisciplinare Regionale della Sicilia di Palazzo Abatellis a Palermo. Della scultura ad alto rilievo, in marmo di Carrara, non si hanno notizie documentarie certe circa l’anno di realizzazione e l’autore, pur potendosi collocare, per lettura analogica con produzioni simili per stile e destinazione, attorno al XVII secolo. Inoltre, l’attento studio dei materiali costitutivi ha permesso di aggiungere un …

Polar Wax as Adhesion Promoter in Polymeric Blend Films for Durable Photovoltaic Encapsulants

2022

Technological developments in the solar photovoltaic field must guarantee the high performance and low deterioration of solar cells in order for solar power plants to be more efficient and competitive. The solar cell needs comprehensive protection offered by a polymeric encapsulant, which improves UV stability, reduces water and moisture absorption, reduces oxygen and vapor permeability and enhances mechanical resistance. Moreover, high transparency and adhesion yields improved the solar panel performance. The current work analyzes polymeric films based on poly(ethylene-co-vinyl acetate) (EVA) and polyolefin (PO) for photovoltaic encapsulant use (the high temperature resistance is improved …