Neutron spectroscopy of water adsorbed on silica

Computational and real neutron scattering experiments are presented. The computations were performed in a modern cluster approximation, which is used in computational chemistry. The amplitude-weighted densities of the vibrational states for a few models of the water molecule depositions at the surface are obtained. The results are in good agreement with the experimental inelastic neutron scattering spectra. © 1991

UNIVERSAL METHOD OF DETERMINING BROMIDES IN RAW MATERIALS AND PRODUCTS FORMED IN MAGNESIUM PRODUCTION

This article presents a method of determining bromides in substances that also contain significant quantities of chlorine ions. This problem has become particularly important in analyzing magnesium electrolytes (carnallites, bischofite, etc.) Detecting a halide in a substance that consists mainly of other types of compounds is always a challenging analytical problem. The main method used commercially to produce magnesium is the electrolysis of a molten mixture of the nonaqueous chlorides MgCl 2 , KCl, and NaCl. The melt is obtained using dewatered carnallite or bischofite. Manufacturers also use magnesium chloride MgCl 2 obtained either as a product of the chlorination of magnesium oxide MgO or a by-product of titanium production (here, highly pure MgCl 2 is obtained as a result of the reduction of titanium tetrachloride by magnesium). The electrolysis temperature is 700-720°C and the process is carried out with graphite anodes and steel cathodes [1]. In practice, the choice of electrolyte is very important. The choice is made on the basis of the melts or solid salts fed into the electrolysis bath and the feed rate, which in turn depends on the concentration of MgCl 2 in the electrolyt

Neutron scattering from water adsorbed on ultrafine nickel particles

A modified NDDO method is applied to the Ni cluster calculations. The calculated amplitude-weighted density of vibrational states spectrum for (Ni11+H2O) clusters fits the experimental inelastic neutron scattering spectrum obtained at 80 K well for highly dispersed Ni particles covered with water. © 1991

New Generation of Compositional Aquivion®-Type Membranes with Nanodiamonds for Hydrogen Fuel Cells: Design and Performance

Compositional proton-conducting membranes based on perfluorinated Aquivion®-type copolymers modified by detonation nanodiamonds (DND) with positively charged surfaces were prepared to improve the performance of hydrogen fuel cells. Small-angle neutron scattering (SANS) experiments demonstrated the fine structure in such membranes filled with DND (0–5 wt.%), where the conducting channels typical for Aquivion® membranes are mostly preserved while DND particles (4–5 nm in size) decorated the polymer domains on a submicron scale, according to scanning electron microscopy (SEM) data. With the increase in DND content (0, 0.5, and 2.6 wt.%) the thermogravimetric analysis, potentiometry, potentiodynamic, and potentiotatic curves showed a stabilizing effect of the DNDs on the operational characteristics of the membranes. Membrane–electrode assemblies (MEA), working in the O2/H2 system with the membranes of different compositions, demonstrated improved functional properties of the modified membranes, such as larger operational stability, lower proton resistance, and higher current densities at elevated temperatures in the extended temperature range (22–120 °C) compared to pure membranes without additives