Solvay (Italy)

The problem of the active stabilization of ship motions is particularly important in the case of pleasure boats or in any case of passenger ships, since the commercial value of the ship is directly related to the comfort of the load transported in this case “people”, considered as stresses induced on them by the vessel movements, with particular attention to roll, given the ship geometric characteristics. Naval architects developed trough the years different solutions to reduce the roll of the ship, and consequentially to increase the passengers comfort, and the development of this solutions followed the progress of technology. Active fins have been the most used, but now the gyroscope solution is coming out with interesting solutions also for large yacht with displacement over 1000 t. The paper aimed at making a interactive comparison between the two systems: active fins and gyroscopes, trough the case study of a yacht of 77.77 m, in order to evaluate if, assuming the same capability to reduce the roll for each one of the two systems, there are other advantages or disadvantages from the point of view of the naval architecture, in particular the resistance of the hull. In fact the importance of the resistance on high Froude number hulls, like planning hulls it is well known, but the paper aimed at giving result useful for naval architects also on traditional displacement hulls, like the one considered here, in order to give also a contribution for preliminary design. The interactivity of the process has been realized using not a theoretical estimation of the gain resistance of the ship according to equations etc. but real tank tests on the hull, according to International Towing Tank Conference methodology, with and without appendages.

The function of catalytic layers in fuel cells and electrolyzers depends on the properties of the ionically conductive phase, which are most commonly perfluorinated ionomers based on Nafion and Aquivion. An analysis by atomic force microscopy reveals that the ultrathin ionomer films around Pt/C agglomerates have a thickness distribution ranging from 3.5 nm to 20 nm. Their conductivity and gas permeation properties determine the fuel cell performance to a large extend. For electrodes in Aquivion-based membrane-electrode-assemblies operation-induced structure changes were investigated by means of material- and conductivity-sensitive atomic force microscopy, infrared spectroscopy and electron-dispersive X-ray analysis. The observed thinning of the ultrathin ionomer films was mainly caused by polymer degradation deduced from reduced swelling after long-time operation and a significant loss of ionomer with operation time detected by infrared spectroscopy. From the linear thickness increase of the ultrathin films with rising humidity, a mainly layered structure of the ionomer was deduced. An influence of thickness of such ultrathin ionomer films on fuel cell lifetime was found by analysis of differently prepared membrane-electrode-assemblies, where a linear increase of irreversible degradation rate with ionomer film thickness in the electrodes of unused membrane-electrode-assemblies was found.

Abstract We describe the rational design of a new versatile family of bifunctional catalytic materials based on the combination of supported metal nanoparticles (Pd, Rh, Ru) and the superacid, perfluorinated Aquivion® PFSA polymer. The heterogeneous catalysts were tested in the multi‐step valorisation of representative plant derivatives to high‐added‐value chemicals. Particularly, the conversion of (+)‐citronellal to (‐)‐menthol and levulinic acid to γ‐valerolactone was achieved in one pot and in one stage in the water phase and shows full selectivity at a high conversion level under mild reaction conditions. The results are discussed in terms of the catalyst micro‐structure.

Polymeric membranes are the most used separation media at industrial level, in biomedical, food, and water treatment fields, thanks to the easy preparation techniques, high flexibility, and low cost. Membrane separation has been recognized as a green sustainable process, the preparation route of polymeric membranes is still based on the use of toxic solvents and fossil-based polymers, which is not yet green and sustainable. Recently, an increasing number of research studies were reported, which referred to the possibility of producing polymeric membranes by using less-toxic solvents and biomaterials. This chapter is an overview of the polymeric membranes applied in desalination, water, and wastewater treatment, including biomaterials and the use of nontoxic solvents in membrane preparation. Finally, a cost analysis of polymeric membrane production comparing toxic and nontoxic solvents and the possibility of solvent recovery is also discussed.