A new type of potentiometric sensors based on perfluorinated,sulfonated cation-exchange membranes for quantitative analysis of multicomponent aqueous solutions

The organization principles of a new type of sensors were developed whose analytical signal is the Donnan potential at the ion-exchange polymer/test solution interface (PD-sensors) for the determination of organic and inorganic electrolytes in multicomponent aqueous solutions. It was found that the cross sensitivity of PD-sensors based on perfluorinated, sulfonated cation-exchange polymers (PSPs) in the initial inorganic forms depends on the potential-determining reactions of protolysis and ion exchange at the PSP/multicomponent test solution interface. The effects of the hydrophilicity, moisture capacity, and ionic form of the ion-exchange polymer on PD-sensor sensitivity were investigated. It was found that treatment of PSP with ethylene glycol at the glass-transition temperature of the polymer makes it possible to obtain modified PSPs in organic forms, which differ from the initial materials by a larger concentration of dissociated counterions, and thus lead to enhanced PD-sensor response and sensitivity to an appropriate organic component. Potentiometric multisensor systems including cross-sensitive PD-sensors, ion-selective electrodes (ISEs), and algorithms for the processing of multidimensional data for the quantitative determination of lysine, novocaine, lidocaine, thiamine, pyridoxine, nicotinic acid, and alkali and alkaline earth metal cations in multicomponent solutions were developed.     

Small-angle scattering study of colloidal particles in heavy crude oils

The structural and dispersion characteristics of samples of heavy crude oils and fractions isolated from them have been studied. A method of in situ analysis of the aggregation of asphaltenes directly in crude oils on the basis of small-angle X-ray scattering is proposed. It has been shown that the maximum size of scattering particles in all crude oil samples is limited to the value on the order of 8.0 nm; the average diameter is ∼2.0 nm. It has been found that the fraction with sizes of 0.8–2.5 nm is mostly composed of resins. Asphaltenes in crude oils form larger aggregated particles with a size up to 8 nm. A comparative study of model dilute solutions of asphaltenes in toluene (0.23 wt %) has shown that the major part of asphaltenes in the liquid (∼94%) is in the form of individual molecules with a size of 0.4–1.2 nm, and only an insignificant remaining part (∼6%) occurs in the form of large aggregates.     

Sinking a structural element into the ground from a water-based platform

A mathematical model is proposed for the sinking of a structural element into the ground by means of an artillery system mounted on a water-based platform.