In the framework of simple volumetric models of electron concentration in the F layer of the polar ionosphere, the influence of non-stationary convection on the state of radio paths in high latitudes is considered. Calculations of three-dimensional trajectories of HF-radio beams showed a significant difference for quiet and disturbed conditions
Keywords: ionosphere, refraction, convection, plasma, radio beams, high latitudes
The absorbing apparatus serves to extinguish the impact when the wagons cohere and move. Most of the energy, about 80%, in this system is absorbed by a friction unit consisting of a friction wedge and a fixed plate. Absorption of energy in this system occurs due to the work of frictional forces arising during longitudinal motion of the pressure wedge with respect to the friction plate. Due to the large shock-frictional loads, intensive wear and destruction of the cermet cake occurs, which adversely affects the energy capacity of the absorbing apparatus. To eliminate these shortcomings, studies were conducted to create a new material. After numerous experiments, a composition was obtained with the optimum content of components, which maximally satisfies the working conditions of the friction unit and the requirements imposed on these devices.
Keywords: absorbing apparatus, friction unit, cermet, wear resistance, friction plate, powder material, sintering technology
The possibility of detecting viruses in biomedical research using the optoacoustic method with carbon nanotubes is considered in the paper. In this paper, we consider the setup used to detect optoacoustic responses from a sample, which allows the recording of optical-acoustic signals generated by carbon nanotubes attached to the surface of viruses in the blood and which have high optical absorption. When the sample is irradiated, the absorbed energy from the laser radiation is converted into kinetic energy by means of energy exchange processes. This leads to local heating and, consequently, to the appearance of a wave of sound pressure. By recording ultrasonic waves, it is possible to form a spectrum of the optoacoustic signal for the test sample, which can be used to detect the absorbing components in it.
Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production
Described trends in the application of two-dimensional-periodic absorbing structures in optical and THz range. The results of calculation of the scatter and reflection of multilayer structures. Designed optimal parameters of the structures to monitor the greatest effect absorption.
Keywords: resonant absorption, plasmons, reflection coefficient, diffraction gratings, periodic structures
Passive detection sensors are widely spread in engineering-technical systems of information protection. During designing such systems, it may be difficult to calculate the coverage areas of infrared detectors. This is due to the fact that the problem of establishing a relationship between the theory of statistical detection and the choice of parameters for the equation of the maximum detection range is not considered in detail. In this regard, the task was to develop a method for applying the basic equation of passive location to calculate the coverage areas of infrared detectors. The calculation method is developed on the basis of the equation of the maximum range of the passive receiver. The study considered three models of the signal-to-noise ratio: a signal against a white noise background with fully known signal-to-noise parameters; detection of a signal whose phase and amplitude are unknown; and detection of a random signal against a noise background. As a result of the research, the conditions under which the passive signal detection formulas on the background of noise give correct results were found. Thus, the connection of the statistical theory of detection with the equation of the range of the passive emitter was established.
Keywords: information security, infrared detector, passive location, engineering and technical protection, the pyroelectric element
Diffraction characteristics of the gratings are calculated by two methods - method of approximate boundary conditions and a strict method based on the numerical and analytical solution of the two-dimensional integro-differential equation. Results of the graphene diffraction gratings calculations are presented.
Keywords: graphene, graphene gratings, volume integral equations, plasmons, coefficient of reflection
The problems of studying the mathematical interpretation of the results of trajectory measurements in terms of increasing the accuracy of identification of bearings of unmanned aerial vehicles during their movement in the group "swarm" and "system" are discussed. The variants of identification of horizontal (IHP) and spatial bearings (PPI) are proposed both separately and in a complementary application. Identification of bearings of similar objects in the swarm type group is expedient to be carried out according to the IGP-IPP algorithm. However, it is only partly operational at distances of 3 km or more. As the main algorithm for identifying bearings of similar objects in the "Story" group, it is advisable to use IPP. Although these algorithms achieve high identification efficiency under favorable conditions, with tougher conditions, they drop rather sharply. Therefore, to maintain a high level of probability of "pure" identification, it is advisable to use additional measures to combat false triads. For the removal of problems, it is necessary to develop and apply combinatorial algorithms for exhaustive search, which is the direction for the development of further research.
Keywords: unmanned aerial vehicle, group of objects, bearing identification, horizontal bearing, spatial bearing, identification criteria, false notch
Are represented the results of studies on the development of teploognezashchitnykh composition cement solution mixtures on the distended vermiculite and the pumice with the application of a multifunctional additive D -5. Are proposed the compositions of teploognezashchitnykh composition mortars, which make it possible to substantially improve the physicomechanical properties of solution mixtures and solution. The introduction of multifunctional additive D -5 to solution mixtures makes it possible to improve the properties of composition solution mixtures and to improve the characteristics of solution. The replacement of the fine dispersed fraction of the distended vermiculite d0,63 mm does not produce by pumice by the volume in the solution mixtures a noticeable increase in solution density, in this case their strength characteristics grow. The developed composition solution mixtures correspond to requirements ALL-UNION STATE STAN. 28013–98 and have low prime cost due to the use of the pumice
Keywords: portland cement, the distended vermiculite, pumice, additive D -5, teploognezashchitnyy composition solution, transverse strength and compression, the mobility of mixture, exfoliation property, the density
Laser tracking locators have certain drawbacks, among which there is a strong influence of the atmosphere on their energy and precision parameters, the process of aiming a narrow beam at the object, etc. High requirements for locators (the error of measuring the range to a few centimeters) lead to the need to take into account the state of the atmosphere on the route for application Corrections in the measurements. In particular, the phenomenon of refraction leads to a significant distortion of the signal. To reduce the error of distance measurements it is advisable to use methods to compensate for the effect of refraction or to take it into account and use the correction coefficients. The article shows that the effective solution to this problem in the absence of the possibility of obtaining operational and accurate information about meteorological parameters is the use of parallel laser probing of the atmosphere. More promising in this case is the use of laser methods for controlling atmospheric parameters, which we described and experimentally investigated at the Chauda, Feodosiya, and the Republic of Crimea provinces. The obtained atmospheric data were used to create a mobile laser-television locator for external-trajectory measurements of the descent of the aeroelastic systems "Kafa" and were installed both on the ground and on an air balloon. The trajectories of the descent of balloons and cargo parachute systems were studied.
Keywords: Laser tracking locator, ranging channel, atmospheric effect, refraction, model compensation method, laser probing
Refraction has a strong influence on the accuracy parameters of the range-finding tract of laser tracking locators and the process of directing a narrow laser beam onto the object. High requirements for locators (the error of measuring the range to a few dozen centimeters) lead to the need to take refraction into account for making corrections to the measurements. Significant distortion of the signal leads not only to the phenomenon of static refraction, but also dynamic. To reduce the error of distance measurements it is advisable to use methods to compensate for the effect of static refraction or to take it into account and use the correction coefficients. The article shows that the most effective solution to the problem of refraction in the presence of a dynamic component is also the use of parallel laser probing of the atmosphere, but it must be carried out at two different wavelengths. In this case, the main method of calculating the correction factors is the dispersion method, which makes it possible to reduce the relative measurement error to 106. The use of laser methods for controlling atmospheric parameters, including two-wave and two-frequency ones, was described by us and experimentally investigated at the Chauda, Feodosiya, and the Republic of Crimea fires on YAG: Nb3 + IZ-25 lasers and continuous lasers . The obtained atmospheric data on the LT-5Z laser were used to create a mobile laser-television locator for external-trajectory measurements of the descent of the aerial systems "Kafa +" and were installed both on the ground and on an air balloon. The flight trajectories of balloons and the descent of cargo parachute systems were studied.
Keywords: Laser tracking locator, ranging channel, atmospheric effect, static refraction, dynamic refraction, dispersion compensation method, laser two-wave probing of the atmosphere
in the article the questions of modeling of thermal effects in vortex tubes with application software, for example, CFD-complex is Studied. Discusses the practical applications of thermal effect in vortex tubes, is proposed using the process of refrigeration in vortex tubes for climate control in vegetable stores with the aim of improving the safety of the products. This article is of interest to a wide circle of readers, dealing with issues of simulation software packages.
Keywords: heat effect, cooling, heating, microclimate, modeling, CAD software program, 3D model. CFD-complex is Studied, FlowVision
The article discusses the methodology of assessing the technical condition of the regenerative air heater RVP-54 on power boilers Naberezhnye Chelny CHP on the basis of the results of the monitoring of the thermal efficiency. In article the algorithm of monitoring and evaluation of the thermal efficiency of regenerative air heater, allows in real time to compare actual performance with previous values and to eliminate the revealed violations.
Keywords: Naberezhnye Chelny CHP, energy boiler, regenerative air heater RVP-54, technical condition assessment, commissioning and configuration, thermal calculation, temperature difference, heating surface, thermal efficiency, heat losses
The article describes the problems of mathematical modeling of large systems. Scientific novelty of the work consists in the implementation of a new numerical method for solving systems of linear algebraic equations. This method is based on a targeted random search and stochastic calculations whith using of cloud technologies.
Keywords: system of linear algebraic equations, cloud computing, self-organization, metric
The transverse vibrations of the beams of a constant cross section are taken into account, taking into account the damping. We consider random oscillations of a beam under the action of vector kinematic and dynamic effects. The examples show the influence of correlation coefficients on the standard deviations of the cross sections of a beam. The internal forces in the form of bending moments and transverse forces are determined. An example of an action of a random process with a latent periodicity is given
Keywords: Beam, damping, deflection, bending moment, shear force, random process, spectral matrix, correlation, vector, matrix, transfer function
The interrelation of pedestrian accessibility of facilities for disabled people with the functional composition of these facilities is considered, a methodology for formalizing such a relationship
Keywords: architectural typology, invalids, pedestrian accessibility, objects of specialized services, stepped system of service