Malko A. Control of the concentration of surface-active substances in liquid media on dynamic surface tension

The thesis developed a way to control the concentration of surfactants on the dynamic surface tension. To implement this method, a method for determining the dynamic surface tension for maximum pressure of the meniscus in a pulsating gas meniscus is proposed. The essence of the method is that by the direct and reverse flow of gas in the meniscus, the process of being implemented in the vicinity of the meniscus ripple maximum pressure value that uniquely identifies the surface tension of each cycle. The effect is that the bubble, with each cycle, doesn't slam after passing the maximum pressure and transit to a new steady state of equilibrium, i.e., adsorption of surfactants is at the same surface of the interface. The possibility of implementing the proposed method is theoretically justified by developing a mathematical model of the process of meniscus pulsation in the vicinity of maximum pressure in a closed system with respect to the number of gas phase. By results for the first time theoretically grounded possibility and conditions of the phenomenon of hysteresis abrupt transition during extrusion and suction blisters, which was experimentally confirmed. On the basis of experimental studies were provided working relationships for determining the concentration of surfactants in aqueous solutions by the value of the surface tension. On the basis of theoretical studies was offered a block diagram of the device and is designed to control the concentration of surface-active substances in liquid environments. Was achieved metrological analysis of the developed device. Was done the laboratory and field testing of the developed device, which confirmed its efficiency and ability to be used for controlling of concentration in solutions for different process fluids, where surface-active substances are used.