Approaching a methodology for the development of a multilayer sound absorbing device recycling coal bottom ash

The aim of the present work has been to develop a methodology which accurately predicts the acoustic behavior of a material without having to manufacture large panels and testing them in reverberation room. Moreover, it can be predicted the sound absorbing performance at normal and random incidence of the sound wave on a material for different thicknesses and multilayer configurations, dramatically reducing the number of experimental tests. This methodology might decrease the cost of the investigation, which is particularly important when dealing with recycled materials that must compete with commercial products used in the same application.     

Frost heave in argon

The freezing of argon in silica powder is observed to generate bands of pure solid argon in the same manner as in the phenomenon of ice lens formation in the freezing of moist ground. A first principles dynamical theory describes the mechanism of lens formation by the thermomolecular pressure-driven flow of interfacially melted films at the lens-solid boundary.     

Nanostructuration of soft hydrogels: synthesis and characterization of saccharidic methacrylate gels

With the tremendous development of biosensors, there is a strong need in new biocompatible materials avoiding possible denaturing of biological species, which can be easily processed with already existing technologies. The scope of this study was to develop new hydrogels which could be nanostructured by common lithographic methods. Therefore, new methacrylate hydrogels are described, which include functionalized monomers bearing either neutral groups, such as saccharidic moieties, anionic, or cationic groups. The gels have been synthesized by redox or photochemical-initiated radical polymerization. Their porosity has been characterized by thermoporometry, AFM, and electronic microscopy. The kinetics of the photocross-linking has been analyzed by piezorheometry on some of the materials and has been shown to be compatible with technological process time range. Although the obtained hydrogels are soft, their nanostructuration into 500-nm patterns could be performed by nanoimprint photolithography process, and these patterns were observed to be stable for several months.