Wave processes on the free surface of water in a channel are considered when semicylindrical capillary waves are excited by a source and a quarter-wave resonator inside the channel. It is shown that ...the experimentally detected accelerating surface flows on the water surface in channels with installed sources and resonators of semicylindrical capillary waves are associated with the excitation of waveguide waves in the channel. Waveguide waves with a distributed amplitude in the form of a standing wave are formed when semicylindrical capillary waves are excited in the section of the liquid surface in a channel. For capillary waves in the channel, the liquid surface is a waveguide open at both ends; waveguide waves are formed due to the reflection of part of the semicylindrical waves from the channel walls and their interference. Waveguide waves propagate after the waves emanating from the source with acceleration and produce an accelerating surface energy flow and, together with it, a surface flow of liquid due to the transfer of momentum to particles of the liquid. In contrast to semicylindrical waves, the front line of waveguide waves within the channel are straight like in plane waves, but the amplitude and intensity of these waves are maximal along the channel axis. The waves emanating from the source in subsequent periods of oscillations are superimposed on the flow produced by the waveguide waves and, as a result, their semicylindrical front lines are extended. The principle of generating an accelerating surface fluid flow by waveguide waves in a channel with a source and a capillary wave resonator can be used to produce acoustic flows in bounded media by sources of acoustic and ultrasonic semicylindrical and hemispherical waves. Using the same principle, it is possible to obtain directed flows of microwave electromagnetic energy in waveguides with open cavity ends by a source of semicylindrical waves inside the waveguide cavity.
The generation of a directed flow on the water surface in channels with sources and resonators of capillary oscillations is detected and investigated. The surface flow is caused by the movement of ...the liquid through the gaps between the resonators, as well as between the resonator and the channel walls, under a curved surface that is locally deformed by the sources of capillary vibrations, the transfer of energy of the locally curved surface of the liquid by capillary waves, and the transmission of wave momentum to the particles of the liquid surface in one direction. It is shown that capillary waves together with the energy transfer an excess surface, the flux density of which is equal to the flux of the surface deformation. Moving devices with a capillary-wave accelerator of the surface liquid flow are demonstrated.
The Russian Academy of Sciences and Federal Space Agency, together with the participation of many international organizations, worked toward the launch of the RadioAstron orbiting space observatory ...with its onboard 10-m reflector radio telescope from the Baikonur cosmodrome on July 18, 2011. Together with some of the largest ground-based radio telescopes and a set of stations for tracking, collecting, and reducing the data obtained, this space radio telescope forms a multi-antenna ground-space radio interferometer with extremely long baselines, making it possible for the first time to study various objects in the Universe with angular resolutions a million times better than is possible with the human eye. The project is targeted at systematic studies of compact radio-emitting sources and their dynamics. Objects to be studied include supermassive black holes, accretion disks, and relativistic jets in active galactic nuclei, stellar-mass black holes, neutron stars and hypothetical quark stars, regions of formation of stars and planetary systems in our and other galaxies, interplanetary and interstellar plasma, and the gravitational field of the Earth. The results of ground-based and inflight tests of the space radio telescope carried out in both autonomous and ground-space interferometric regimes are reported. The derived characteristics are in agreement with the main requirements of the project. The astrophysical science program has begun.
—
It is shown that the working volume of the RED-100 two-phase emission detector, which operates in a ground-based laboratory with liquid xenon used as a working substance, is a source of ...single-electron noise signals with a characteristic frequency of ~200 kHz. Possible mechanisms of generation of these noises and methods for their suppression are discussed.
—
A combined passive shield of the RED-100 two-phase emission neutrino detector has been developed and built for suppressing the background of external γ rays and neutrons. The shield is composed of ...a 5‑cm-thick copper layer (the inner layer is adjacent to the detector) and a water layer with a total thickness of approximately 70 cm (including the water inside the copper shield). The Monte Carlo simulation of the shielding efficiency has been performed. The obtained attenuation factor of the copper shield for the γ-ray background has been experimentally verified in a laboratory test using a NaI(Tl) scintillator detector. The γ‑ray background rejection factor of the full shield has also been calculated.
The work done on the test site to ensure the operational safety of the powerhouse of the Zagorsk PSP-2 after its leveling is described. The controlled compensation grouting technology for leveling ...the powerhouse of the Zagorsk PSP-2 is substantiated.
This paper addresses the stability analysis of a class of switched nonlinear systems. The switched systems have uncertain nonlinear functions constrained in a sector set, which are called admissible ...sector nonlinearities. A sufficient condition in terms of linear inequalities is presented to guarantee the existence of a common Lyapunov function, and thereby to ensure that the switched system is stable for an arbitrary switching signal and any admissible sector nonlinearities. A constructive algorithm based on the modified Gaussian elimination procedure is given to find the solutions of the linear inequalities. The obtained results are applied to a population model with switchings of parameter values and the conditions of ultimate boundedness of its solutions are investigated. Another example of an automatic control system is considered to demonstrate the effectiveness of the proposed approaches.
The article describes a prototype device for monitoring the level of phase separation, which can be used for operational control of the delayed coking process in the petrochemical industry. A scheme ...and design of an experimental device developed by the authors, consisting of an organic plastic scintillator and an array of silicon photomultipliers, is presented. A computer simulation of the response of a scintillation detector under conditions of the actual geometry of the coke drum is presented. Experimental results demonstrating the performance of the device are presented.
PDF
