Volga State University of Water Transport

About: Volga State University of Water Transport is a education organization based out in Nizhny Novgorod, Russia. It is known for research contribution in the topics: Attractor & Deformation (engineering). The organization has 71 authors who have published 75 publications receiving 224 citations.

Partial synchronization in the second-order Kuramoto model: An auxiliary system method

Abstract: Partial synchronization emerges in an oscillator network when the network splits into clusters of coherent and incoherent oscillators. Here, we analyze the stability of partial synchronization in the second-order finite-dimensional Kuramoto model of heterogeneous oscillators with inertia. Toward this goal, we develop an auxiliary system method that is based on the analysis of a two-dimensional piecewise-smooth system whose trajectories govern oscillating dynamics of phase differences between oscillators in the coherent cluster. Through a qualitative bifurcation analysis of the auxiliary system, we derive explicit bounds that relate the maximum natural frequency mismatch, inertia, and the network size that can support stable partial synchronization. In particular, we predict threshold-like stability loss of partial synchronization caused by increasing inertia. Our auxiliary system method is potentially applicable to cluster synchronization with multiple coherent clusters and more complex network topology.

Using Carbon-Based Composite Materials for Manufacturing C-range Antenna Devices

Abstract: Abstract C-range horn antenna made of a graphene-containing carbon-based composite material has been developed. Electrodynamic characteristics of the developed antenna and the identical metal antenna have been measured in the frequency range of 4.6–4.9 GHz. We have created two prototypes of horn antennas made of (i) carbon fiber and (ii) carbon fabric. It has been shown that the horn antenna made of graphene-containing composite material is capable of efficiently operating in the C-range frequency and possesses almost the same electrodynamic characteristics as the conventional metal antenna of the same geometry and size. However, the carbon-based antenna has enhanced stability in the wide range of temperatures to compare with the corresponding metal antenna.

Chaotic driven maps: Non-stationary hyperbolic attractor and hyperchaos

Abstract: In this paper we study simple examples of non-autonomous maps having different changing in time chaotic attractors. We present the definition of non-stationary hyperbolic attractor of the driven maps. We rigorously prove the existence of non-stationary hyperbolic attractor in 2D driven map and introduce a hyperchaotic attractor for autonomous 3D map of master-slave structure. Our analysis is based on the auxiliary systems approach and the construction of invariant cones.

The Temperature Behavior of Microwave Absorption of Metal Oxide Powders When Heated by a 263-GHz Gyrotron Radiation

Abstract: In this paper, the temperature dependence of microwave absorption in powders of various metal oxides was studied. The powders of aluminum oxide Al2O3, zinc oxide ZnO, tungsten trioxide WO3, and titanium dioxide TiO2 were the test substances. A subterahertz gyrotron setup with a frequency of 263 GHz and an adjustable output power level from watts to 1 kW was used as a radiation source. In the experiments, the samples of the powders were heated by the radiation of the gyrotron, and at the same time, the temperature of the sample was recorded and the power absorbed in the sample was measured by the calorimetric method. The measurements were carried out in a wide range of temperatures: from several tens up to 1200 °C. The results obtained may be of both fundamental and applied interest for researchers engaged in microwave heating of materials.

Synchronization Thresholds in an Ensemble of Kuramoto Phase Oscillators with Randomly Blinking Couplings

Abstract: We consider a network of Kuramoto phase oscillators with randomly blinking couplings. Applicability of the averaging method for small switching intervals is rigorously substantiated. Using this method, we analytically estimate the threshold coupling force for synchronizing the ensemble oscillators. The threshold synchronization is studied as a function of the switching interval for various network sizes. The effect of preserving synchronization for a significant increase in the switching interval is found, which is the key feature of the system since a slight increase in this interval usually leads to the synchronization failure. The intermittent-synchronization possibility for small network sizes and large switching intervals is shown. An increase in the network size is shown to result in a stability increase due to the decreasing probability of appearance of uncoupled configurations. The regions corresponding to the global synchronization of oscillators are singled out in the system-parameter space.