Transient Response of the Acid-base Diode for Polarity Change

An application of the so-called acid-base diode would be the sensitive detection of nonhydrogen cations in an acidic medium based on salt-effects. For diode purposes different connecting elements between the acidic and aqueous reservoirs of the diode were developed, namely a polyvinyl alcohol (PVA) hydrogel cylinder, and a polyvinyl butyral (PVB) membrane. During the measurement of the voltage – current characteristic (VCC) of the diode, it was found, that in the case of PVA gel cylinder an overshoot (a local maximum followed by a local minimum) appeared in the time vs. current curve, while the diode was switched between modes (open or closed), that is the direction of the applied voltage was reversed. The overshoot did not appear in PVB membrane.The existence of overshoots was studied by numerical simulations. The time response of the diode with different hypothetic connecting elements was investigated, when the diode was switched between modes via changing the polarity of applied voltage. We found that larger diffusion coefficients of hydrogen and hydroxide ions explain the appearance of overshoots. By examining the concentration and potential profiles a qualitative explanation of this phenomenon was given.

Three-Saddle-Foci Chaotic Behavior of a Modified Jerk Circuit with Chua’s Diode

This paper investigates the chaotic behavior of a modified jerk circuit with Chua’s diode. The Chua’s diode considered here is a nonlinear resistor having a symmetric piecewise linear voltage-current characteristic. To describe the system, we apply fundamental laws in electrical circuit theory to formulate a mathematical model in terms of a third-order (jerk) nonlinear differential equation, or equivalently, a system of three first-order differential equations. The analysis shows that this system has three collinear equilibrium points. The time waveform and the trajectories about each equilibrium point depend on its associated eigenvalues. We prove that all three equilibrium points are of type saddle focus, meaning that the trajectory of (x(t),y(t)) diverges in a spiral form but z(t) converges to the equilibrium point for any initial point (x(0),y(0),z(0)). Numerical simulation illustrates that the oscillations are dense, have no period, are highly sensitive to initial conditions, and have a chaotic hidden attractor.

A study of line-plane configuration in the Corona discharge theory

Research on corona discharges from plasma generators has been studied using the line-plane configurations (L-PC). The purpose of this study is to calculate the comparison of the level of conformity of the voltage current characteristic curve (I–V) from the simulation results of numerical calculations of the electrode geometry function and the results of experimental data. There is an electrode (electrode 1) in the form of a rectangular plate with a very thin thickness which has a length and width of a and b respectively in an upright position (line configuration). Electrode 1 has a distance of c to electrode 2 which is in a lying position (plane configuration) below the electrode 1. Furthermore, by using variation of c of 2.5 cm, 2.8 cm, 3.1 cm and 3.4 cm, the two electrodes are connected to the plasma generating equipment, thus producing a plasma discharge that comes out of the tip of the electrode 1 towards electrode 2. Research results from all variations of c prove that there is a high degree of suitability between numerical calculations with experimental data by taking the value of the fitting for the sharpness shape factor of k in the area with the largest plasma discharge.

SIMULATION OF THE CURRENT-VOLTAGE CHARACTERISTICS OF SOLAR BATTERIES WITH CONSIDERING DECREASE OF LIGHTING DUE TO THE INFLUENCE OF JETS OF THE ELECTRIC PROPULSION

A model for calculating the voltage-current characteristic of a solar array in the presence of a temperature gradient by its photovoltaic converters and their variable illumination due to possible pollution under the action of space factors, including operation of electric rocket engines, is described. The model is based on the main equation of a solar cell. In this case both a one-dimensional and a two-dimensional temperature gradients are taken into account. The principles of constructing a model are given, and the initial data selection is made. To simulate the lighting conditions of the solar array such a concept as effective illumination is used, i.e. the density of the radiation flux which falls on photovoltaic converters passing through the protective coatings. The features of simulation of the temperature distribution in the solar array and the effective illumination of its surface in cases of parallel, serial and mixed switching of solar cells are described. The calculation procedures and examples of solar cells are given. The construction of the model in universal mathematical package Mathcad is described. Some simulation results are discussed. Key words: solar array, mathematical simulation, illumination, temperature gradient, electric rocket engine, spacecraft, Mathcad.