Influence of direct electric field on PMCG-alginate-based microcapsule

In this study, the influence of direct electric current on a microcapsule was investigated. The microcapsule consisted of a core from a calcium ion and sodium alginate (SA) complex and the microcapsule membrane was formed by the polyionic complexation of poly(methylene-co-guanidine) (PMCG) and cellulose sulfate (CS). Microcapsules showed swelling and decreasing mechanical properties under the applied electric current, and the microcapsule membrane showed anisotropic swelling on the electrode side. The effect is attributed to an electrokinetic phenomenon, predominant formation of hydroxyl ions, and the diffusion of hydrated ions. The swelling degree of the microcapsule and microcapsule membrane at different pH and the applied electric current under alkali and acidic conditions was investigated. The swelling degree was influenced by the dissociation of the membrane, which was observed after applying the electric field, which was caused by the electrokinetic effect and the neutralization of the polycation (under alkali conditions) or polyanionic (under acidic conditions) segment during membrane formation.

Акустоэлектрический преобразователь на основе электрокинетического явления потенциал течения

A mathematical model of an acoustoelectric transducer based on the use of the electrokinetic phenomenon of the flow potential is proposed. It is shown theoretically that the flow potential increases in proportion to the strength of the constant electric pumping field, which is confirmed experimentally. The described converter has variable sensitivity. Rather large values of the sensitivity of an electrokinetic microphone have been obtained experimentally. The results of the work can be used in the design of acoustoelectric transducers.

Implementation of a receiving acoustic antenna using an electrokinetic phenomenon of potential flow. Electrochemical aspect

Рассматривается возможность акустоэлектрического преобразования с использованием явления потенциала течения, обратного к другому электрокинетическому явлению - электроосмосу. Обратимость двух этих явлений позволяет использовать один преобразователь, содержащий заполненную жидкостью мембрану, к торцам которой подведены электроды, либо в режиме излучателя, либо в режиме приемника акустической энергии. В первом случае к электродам подается электрическое поле, во втором случае преобразователь находится в стороннем акустическом поле, а с электродов снимается напряжение, отвечающее стороннему акустическому полю. Работа состоит из двух частей. В настоящей части рассматриваются электрохимические аспекты, а именно получается дифференциальное уравнение, связывающее градиенты потенциала течения и акустического давления в теле преобразователя. Из этого уравнения следует выражение для объемной силы в двойном электрическом слое на границе раздела фаз в пористой структуре. Сила вызывается вектором электрической напряженности, возникающей вследствие образования в пористой структуре потенциала течения. Вывод зависимости потенциала течения от перепада давления приводится с помощью аппарата неравновесной термодинамики. Согласно этому подходу электроосмос и потенциал течения описываются уравнениями термодинамики неравновесных процессов, кинетические коэффициенты которых удовлетворяют соотношениям Онзагера, а вся система является линейной, в том числе и относительно перепада давления и потенциала течения. Полученное выражение для объемной силы в жидких порах мембраны позволит в следующей части статьи изучить акустические аспекты процесса акустоэлектрического преобразования на основе использования явления потенциала течения. Предлагаемый подход к созданию приемной антенны на явлении потенциала течения является новым по причине того, что для увеличения эффективности акустоэлектрического преобразования предполагается применение постоянного напряжения накачки на электродах преобразователя. Результаты работы могут быть использованы при теоретической разработке и практическом конструировании обратимых электроакустических преобразователей нового типа, построенных на использовании электрокинетических явлений. The possibility of acoustoelectric conversion using the phenomenon of the potential of the flow, the inverse of another electrokinetic phenomenon - electroosmosis. The reversibility of these two phenomena makes it possible to use a single transducer containing a liquid-filled membrane, to the ends of which electrodes are connected, either in the emitter mode or in the receiver mode of acoustic energy. In the first case, an electric field is supplied to the electrodes, in the second case, the transducer is located in an external acoustic field, and the voltage corresponding to the external acoustic field is removed from the electrodes. The work consists of two parts. In this part, electrochemical aspects are considered, namely, a differential equation is obtained that relates the gradients of the flow potential and acoustic pressure in the transducer body. From this equation follows the expression for the volumetric force in a double electric layer at the phase boundary in a porous structure. The force is caused by the vector of electric tension arising from the formation of the flow potential in the porous structure. The derivation of the dependence of the flow potential on the pressure drop is given using the apparatus of nonequilibrium thermodynamics. According to this approach, electroosmosis and the flow potential are described by the equations of thermodynamics of nonequilibrium processes. The kinetic coefficients of this system satisfy the Onsager relations, and the entire system is linear, including with respect to the pressure drop and flow potential. The obtained expression for the volumetric force in the liquid pores of the membrane will allow us to study the acoustic aspects of the acoustoelectric conversion process based on the use of the phenomenon of flow potential in the next part of the article. The proposed approach to creating a receiving antenna on the phenomenon of flow potential is new due to the fact that in order to increase the efficiency of acoustoelectric conversion, it is proposed to use a constant pump voltage at the electrodes The results of the work can be used in the theoretical development and practical construction of a new type of reversible electroacoustic transducers based on the use of electrokinetic phenomena.

Improving the efficiency of electroosmotic drying of electric motors insulation

The actual problem of electric motors (EM) operation associated with wetting of windings insulation is considered. A new method of EM drying based on electrokinetic phenomenon of electroosmosis was developed at the Department of Electrical Equipment of Vologda State University. It was shown that water molecules can take part in formation of non-mobile hydrated positively charged hydrogen ions. In this case, hydrogen ions become bound, lose their mobility and ability to take part in the process of electroosmotic drying (EOD). EOD efficiency is drastically reduced. It was proved that it is possible to prevent ion hydration, increase their mobility, penetration ability and, thereby, increase the EOD efficiency by applying a pulsed voltage component to the EOD process with a duty factor of 4. As a result, a new EOD method was developed using a pulsed voltage component that increases the speed of EM insulation drying by three times.

Improving the reliability of electric motors during startup using electroosmotic drying of insulation

The article considers the actual problem of electric motors (EM) operation associated with wetting of winding insulation. The condition of wet insulation is getting worse due to aggressive environment of premises of agro-industrial complex, and some workshops in industry. It is noted that together with humidification, the effect of insulation “steaming” occurs after EM is put into operation. In this case, the insulation resistance R sharply decreases and its breakdown may occur, after which a major overhaul of EM is required. A new method for EM drying based on the electrokinetic phenomenon of electroosmosis has been developed. Under the influence of electric field forces, moisture is extruded from insulation capillaries onto the surface of EM winding and stator iron. R increases, and EM becomes ready to turn on. Under further operation, EM is heated and moisture evaporates into the environment. It is shown how electroosmotic drying (EOD) and the developed device (DEOD) help to get rid of the effect of insulation “steaming” and thereby ensure trouble-free EM operation.

Features of electroosmosis usage for drying and moisture protection of electrical equipment

The article describes a new method for drying electric motors and transformers based on electrokinetic phenomenon of electroosmosis. The process of electroosmotic motion of moisture in insulation capillaries is described. The advantages of electroosmotic drying associated with a significant reduction in energy and labor costs are presented.