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In this work the problem of upper detection limit of potentiometric sensors is addressed. Due to deviation of potentiometric plots from cationic Nernstian responses determination of analytes like silver cations in concentrations above 10−2 M is hardly possible, especially in the presence of background electrolyte containing lipophilic anions. Herein proposed approach applied classical complexing ligand, dithizone, attached to gold nanoparticles as ionophore. Immobilization on gold nanoparticles surface effectively anchores ligand molecules within the membrane phase. Thus obtained sensors are characterized with stable, Nernstian, potentiometric responses and selectivity comparable with classical membrane compositions. Moreover, due to lower formation constant of Ag+ with dithizone based ligand, herein reported sensors offer linear, Nernstian responses also in the range of high activity of AgNO3 solutions.

The properties of liquid-crystalline (LC) hybrid systems made of inorganic nanoparticles grafted with photosensitive azo compounds are presented. For materials with a large density of azo ligands at the surface, the LC structure can be reversibly melted by UV light, and the return to the LC state does not require the absorption of visible light. For systems with a lower density of azo ligands, UV light causes shortening of the distance between metal sublayers in the lamellar phase. Interestingly, the azo derivatives attached to the nanoparticle surface show very different kinetics of cis/trans conformational change as compared to the free molecules. The cis form of free ligands in solution is stable for days, whereas the isomerization of molecules attached to the nanoparticle surface to the trans form takes only a few minutes. Apparently, owing to the crowded environment, azo ligands immobilized at a metal surface behave as they would in the condensed state.

The aim of this paper is to present a recent experimental investigation of the wall pressure distribution and flow pattern observed during the filling and emptying of a full-scale silo, with and without, inserts. The experiments were carried out with sand, at the Dept. POSTEC in the Tel-Tek Research Institute in Norway. The results show that the double-cone insert had a strong influence on the flow and pressures in the silo. A skewed flow often occurred when the insert was installed.