Publication in University of Dunaújváros
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Development of ozone generator by modification of the field distribution
Get PDFNew methods have been established to enhance the ozone production of the surface discharge arrangement. One method sets the discharge electrode a short distance away from the surface of the dielectric material, whilst another uses a special power supply system resulting in a superimposed discharge. According to the experiments, significant differences have been found in the ozone production capacity of the different arrangements. The characteristics of the electric field distribution of the designs have been calculated using the finite element method for the potential; and the Donor-Cell method for the space charge calculation, and the results have been analysed. A method of analysis has been established for the calculated field characteristics, which provides two index numbers. The reasons are highlighted for the differences in ozone production in relation to the index numbers obtained from the fields' distributions of the different arrangements
Analysis of plastic peridynamic material with RBF meshless method
Get PDFhe peridynamic material model (PMM) is a new way to describe the material failures with discontinuities. Earlier works, presented by S. Silling, F. Bubaru and etc. introduced the Linear Elastic Fracture Mechanics of peridynamic material. In the recent work, the isotropic hardening plastic extension of PMM is presented. To solve the nonlinear integral equations of the problem the modified Newton method is used with mesh-less spatial discretization. At last some example shows the similarities and different between the results of classical and peridynamic plasticit
Comparison of the bifurcation curves of a two-variable and a three-variable circadian rhythm model
Get PDFTwo dynamical systems describing the circadian fluctuation of two proteins (PER and TIM) in cells are compared. A simplified model with two variables has already been investigated. Detailed study of the possible bifurcation has been carried out. Periodic solutions of the differential equations with 24-h period have been obtained numerically. Here the general, more realistic model having three variables is investigated. The possible phase portraits and local bifurcations are studied in detail. The saddle-node and Hopf-bifurcation curves are determined in the plane of two parameters by using the parametric representation method. Using these curves the number and the type of the stationary points can be determined. The relation of the two bifurcation curves and the Takens–Bogdanov bifurcation points are also studied. The bifurcation curves are compared to those obtained for the simplified two-variable system
Calculation of electron-molecule reactions of NO decomposition in pulsed corona discharges
Get PDFIn recent years there has been increasing research interest in the removal of nitrogen-oxides from exhaust gases using a pulsed corona discharge reactor. The pulsed streamer corona produces energetic electrons that excite, ionize and dissociate gas molecules, and by forming radicals that enhance the gas-phase chemical reactions which reduce the pollutant’s concentration. The decomposition ratio of these substances is dependant on the gas composition, concentration, energy distribution of fast electrons, and other parameters. For a detailed analysis of the phenomena, knowledge of chemical reaction mechanisms is essential. The reaction rates of possible molecule-molecule reactions can in most cases be found in the literature, but the rates of the electron-molecule collision reactions depend on the energy of free electrons. With the knowledge of the field distribution, the energy of the free electrons and the reaction rates can be found. In this paper the authors present a method, in which the reaction rates of the electron- molecule collision are determined. The model is based on a calculation of: the energy of free electrons in the time and space varying field, considering the mean free path and the energy-dependent reaction cross sections of molecules. Knowing the rates, it is possible to solve the reaction kinetic equations, and to get the time-evolution of by-products, and the decomposition ratio of the pollutant gase
The bounds of the distributed data-intensive computing systems
Get PDFThe distributed computational systems and the distribution algorithms are thoroughly studied. In this paper we focus on data-intensive distributed problems including of task distributions, network delay times, join of the part task results, and the effect of non-execution. First we make a study of dedicated multi-computer systems in which the number of computers and the capacity of computers are almost constant. Then we analyze non-dedicated systems where the number and the free capacity of computers are frequently changed. The solution time of the full task depends on a large number of complex parameters. The effects of different parameters are demonstrated by numerical analysis based on behavior of distributed data-intensive super-computing system
An improvement of a theorem of Erdős and Sárközy
No full textLet 12 ... a a, the inequality ( ) ( )( ) ( )21R n g ng nε−≤ − cannot hold from a certain point on
On additive representation function of general sequences
No full textLet 0 ≦ a 1 0 is an integer, then there does not exist n 0 such that d ≦ r 1 (A, n) ≦ d + [√2d + ½] for n > n 0
Kinetic model of hazardous gas decomposition by pulsed corona discharge
Get PDFIn recent years there has been increasing research interest in the removal of nitrogen-oxides from exhaust gases using a pulsed corona discharge reactor. The pulsed streamer corona produces energetic electrons that excite, ionize and dissociate gas molecules, and byforming radicals that enhance the gas-phase chemical reactions which reduce the pollutant’sconcentration. In this paper a method is presented, where the reaction rates of the electron-molecule collision are determined. The model is based on calculation of the energy of free electrons in the time and space varying field, considering the mean free path and the energy-dependent reaction cross sections of molecules. Knowing the rates, it is possible to solve the reaction kinetic equations, and to get the time-evolution of by-products, and the decomposition ratio of the pollutant gase
Phenomenological model of pulsed corona reactor
Get PDFAs it is well known, the non-thermal plasma discharge is an effective way to clean the flue and exhaust gases of hazardous pollutants, like sulphur-oxides, nitrogen-oxides. The decomposition ratio of these substances depends on the gas composition, concentration, energy distribution of fast electrons, and other parameters. For a detailed analysis of the phenomena, the first step is the mathematical description of corona pulses which determines the electric field. The second step is the determination of the electric field distribution inside the reaction chamber. In this paper the authors give an easy model for the pulsed corona current and a simplified model for the electric field by using the corona current and the displacement current pulse shapes. The result of the model is the space and time dependent field distribution, which is suitable for calculating the rate coefficients of chemical reactions
