Post-seismic effectiveness of the strengthening work carried out with FRP applied to historical masonry buildings: the case study of the Spoleto Cathedral

<p>The sequence of major earthquakes that has affected Italy in recent decades has required the use of materials and innovative techniques for the security of damaged buildings. Fibre Reinforced Polymer (FRP) represents a novelty in the field of seismic improvement techniques applicable also to historical masonry buildings. The use of composite materials can respect the conservation principles of the monumental buildings. This study describes the effectiveness of the seismic improvement techniques carried out by means of FRP in the Spoleto cathedral (Italy) after the 1997 Umbria-Marche earthquake. The strengthening work concerned the making safe of damaged vault structures by means of gluing fibreglass bands (GFRP). After 20 years, during the 2016 Amatrice-Norcia earthquake, near Spoleto, the cathedral reinforced with the GFRP bands has not suffered any damage demonstrating the effectiveness of the seismic strengthening techniques.</p>

Preparation and characterization of magnetic graphene oxide nanocomposite (GO-Fe3O4) for removal of strontium and cesium from aqueous solutions

<p>Magnetic graphene oxide nanocomposites (M-GO) were successfully synthesized by partial reduction co-precipitation method and used for removal of Sr(II) and Cs(I) ions from aqueous solutions. The structures and properties of the M-GO was investigated by X-ray diffraction, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer (VSM) and N₂-BET measurements. It is found that M-GO has 2.103 mg/g and 142.070 mg/g adsorption capacities for Sr(II) and Cs(I) ions, respectively. The adsorption isotherm matches well with the Freundlich for Sr(II) and Dubinin–Radushkevich model for Cs(I) and kinetic analysis suggests that the adsorption process is pseudo-second-ordered.</p>