Publications by authors named "V V Vasil'eva"
Article Synopsis
- The study analyzes how heterogeneous polymeric ion-exchange membranes (IEMs) MK-40, MA-40, and MA-41 change in transport and structural characteristics when exposed to high temperatures and aggressive chemical environments over time.
- These membranes, made of ion-exchange polymers reinforced with polyethylene and nylon, suffer from aging and performance degradation due to external factors like heat and chemical solutions such as HSO and NaOH.
- A unique fitting technique is used to calculate five key physicochemical parameters that describe the membranes' transport properties, enabling researchers to assess the effects of artificial aging on the micro- and macrostructure of the polymer materials.
Article Synopsis
- * Key findings include the discovery that increasing resin content reduces the length of the limiting current plateau and the resistances in their current-voltage curves (CVCs) when using sodium chloride solutions.
- * A unique aspect of the research is the identification of two limiting currents in CVCs when mixed with phenylalanine, suggesting that the amino acid participates in additional chemical reactions which generate H/OH ions at the membrane interface, a phenomenon not previously observed in similar systems.
A simple non-steady state mathematical model is proposed for the process of purification of an amino acid solution from mineral salts by the method of neutralization dialysis (ND), carried out in a circulating hydrodynamic mode. The model takes into account the characteristics of membranes (thickness, exchange capacity and electric conductivity) and solution (concentration and components nature) as well as the solution flow rate in dialyzer compartments. In contrast to the known models, the new model considers a local change in the ion concentration in membranes and the adjacent diffusion layers.
View Article and Find Full Text PDFA comparative analysis of the effect of the manufacturing technology of heterogeneousion-exchange membranes Ralex CM Pes manufactured by MEGA a.s. (Czech Republic) on the structural properties of their surface and cross section by SEM was carried out.
View Article and Find Full Text PDF[Somnological status of women in late reproductive and perimenopausal periods during treatment of sleep disorders using partial light deprivation].
Zh Nevrol Psikhiatr Im S S Korsakova
October 2019
Aim: To study the characteristics of somnological status in women in the late reproductive, pre- and postmenopausal periods before and after partial light deprivation.
Material And Methods: One hundred and eighty-four women of menopausal age were included. A polysomnographic study of night sleep was performed and the excretion of the morning fraction of 6-sulfatoxymelatonin in the urine was measured before and after partial light deprivation in the light-saturated months of the year (from April to October) using optical lenses with a mineral photochromic coating.