Polimeryzacja aniliny w środowisku stałego pola magnetycznego

Polyaniline is an example of an electronically conducting polymer. During the oxidation of the polymer, positive charges appear in its structure, which must be compensated for e.g. by the presence of anions in the polymer layer. The form of polyaniline depends on both the degree of oxidation and the degree of protonation of the polymer, i.e. the pH of the solution. Due to the ease of electrochemical preparation of polyaniline, as well as the possibility of full control of the course of the process, the influence of the constant magnetic field (s.p.m.) on the reaction of its preparation was additionally investigated. The cyclic voltammetry (CV) method was used for this purpose. Aniline polymerization processes were carried out on platinum, plate electrodes, not insulated (A) and insulated on two different sides with Teflon, with surfaces directed parallel to the line of force of the s.p.m. (To beat). Research on the electrochemical preparation of polyaniline in s.p.m. allowed to conclude that the following factors affect the magnitude of the current in the tested process: (i) the magnitude of the magnetic induction vector B, (ii) the position of the electrode plane in relation to the direction of the vector B, (iii) the type of electrode (insulated on one side or not). Impact on the impact of s.p.m. the magnetic properties (e.g. paramagnetic, diamagnetic) of the particles participating in the electrochemical reaction, as well as their charge (+/-), also had an effect on the electrochemical polymerization processes. Based on the experimental results, the mechanism of the influence of s.p.m. was proposed. on the tested electrochemical reactions. This mechanism was based, inter alia, on the formation of the magnetohydrodynamic effect (MHD), which causes a change in the speed of transport of the reacting substances to the electrode, the magnetohydrodynamic movement of the electrolyte and the change in the kinetics of electrode processes. For the tested process, changes in the rate constants of electrochemical reactions (ks) as a result of external action of s.p.m. were around 30%.

7-Tesla Functional Cardiovascular MR Using Vectorcardiographic Triggering—Overcoming the Magnetohydrodynamic Effect

Objective: Ultra-high-field B0 ≥ 7 tesla (7T) cardiovascular magnetic resonance (CMR) offers increased resolution. However, electrocardiogram (ECG) gating is impacted by the magneto-hydrodynamic effect distorting the ECG trace. We explored the technical feasibility of a 7T magnetic resonance scanner using an ECG trigger learning algorithm to quantitatively assess cardiac volumes and vascular flow. Methods: 7T scans were performed on 10 healthy volunteers on a whole-body research MRI MR scanner (Siemens Healthineers, Erlangen, Germany) with 8 channel Tx/32 channels Rx cardiac coils (MRI Tools GmbH, Berlin, Germany). Vectorcardiogram ECG was performed using a learning phase outside of the magnetic field, with a trigger algorithm overcoming severe ECG signal distortions. Vectorcardiograms were quantitatively analyzed for false negative and false positive events. Cine CMR was performed after 3rd-order B0 shimming using a high-resolution breath-held ECG-retro-gated segmented spoiled gradient echo, and 2D phase contrast flow imaging. Artefacts were assessed using a semi-quantitative scale. Results: 7T CMR scans were acquired in all patients (100%) using the vectorcardiogram learning method. 3,142 R-waves were quantitatively analyzed, yielding sensitivity of 97.6% and specificity of 98.7%. Mean image quality score was 0.9, sufficient to quantitate both cardiac volumes, ejection fraction, and aortic and pulmonary blood flow. Mean left ventricular ejection fraction was 56.4%, right ventricular ejection fraction was 51.4%. Conclusion: Reliable cardiac ECG triggering is feasible in healthy volunteers at 7T utilizing a state-of-the-art three-lead trigger device despite signal distortion from the magnetohydrodynamic effect. This provides sufficient image quality for quantitative analysis. Other ultra-high-field imaging applications such as human brain functional MRI with physiologic noise correction may benefit from this method of ECG triggering.

Influence of interfacial electrokinetic on MHD radiative nanofluid flow in a permeable microchannel with Brownian motion and thermophoresis effects

In this study, the behavior of a microchannel flow is examined. The fluid is considered to be a nanofluid, which moves between two parallel flat plates in the presence of an electrical double layer. The Buongiorno nanofluid is considered with body force. In this study, the unphysical supposition presented in the preceding work to the discontinuity of the flow fled where the electrostatic potential in the central of the canal must be equal to zero is removed. The incorrect supposition that the pressure constant is preserved, which is considered a known form, is corrected. The current fresh model equation is modified by using dimensionless parameters to convert partial differential equations into ordinary differential equations. The transformed nonlinear equations are solved by the homotopy analysis method. The physical parameters, magnetic parameters, Eckert number, Lewis number, Brownian motion parameters, thermophoresis parameters, and Prandtl number are analyzed. The influence of both the viscous and Joule dissipation in the presence of magnetohydrodynamic effect is examined.

ПЛАНАРНЫЙ ЭЛЕКТРОХИМИЧЕСКИЙ МАГНИТОГИДРОДИНАМИЧЕСКИЙ АКСЕЛЕРОМЕТР

Электрохимические преобразователи на основе магнитогидродинамического эффекта (МГД) предназначены для преобразования внешнего механического возмущения в электрический ток. В данной работе было выполнено моделирование оппозитной планарной структуры МГД-преобразователя, рассчитаны распределения потока жидкости и потоков ионов в преобразователе и оценены характеристики МГД-преобразователя. Electrochemical transducers based on the magnetohydrodynamic effect (MHD) are designed to convert an external mechanical motion into output electric current. The research deals with modeling the opposed planar structure of the MHD transducer, as well as calculating the distribution of the liquid flow and ion flows in the transducer, and estimating the characteristics of the MHD transducer.