metamaterials, microwave, antennas, diffraction, Maxwell equations, electromagnetic waves, the dielectric constant
Keywords: metamaterials, microwave, antennas, diffraction, Maxwell equations, electromagnetic waves, the dielectric constant
This paper considers basic element of device of energy storage which is a piezoelectric generator (PEG) of cylindrical form with the attached inertial mass. A finite element modeling of the device operation is carried out during active load in the external circuit. The main purpose of the operation is to compare the output potential and frequency characteristics of the device known in the literature models of systems with concentrated parameters. On the basis of these models, we can receive the analytical dependence of parameters of PEG with its geometric characteristics and mechanical properties of the used materials. However, the question of the range of applicability of these formulas is still open. In this paper, based on the numerical analysis of finite element models of PEG in package ANSYS, we obtained comparison with the analytical formulas that show the values of some parameters of simplified models and set the boundaries of their applicability.
Keywords: energy storage, PEG, piezoceramics, effective mass, resonant frequency, FEM
The article presents a mathematical model of deformation of thin-walled conical shells, considering orthotropic material, geometric nonlinearity and transverse shear. Showing geometric relationships, physical relationships, the functional of total energy of deformation and boundary conditions.
Keywords: conical shell, tapered panel, mathematical model, geometric nonlinearity, orthotropic, lateral shifts
Acoustic system parameters were selected and calculated: wave modes used when controlling, wave entry and frequency angles according to kind of decay process and ultrasonic attenuation. Control procedure was developed
Keywords: ultrozvuk, frequency, attenuation process, technology, acoustic system
This paper shows the results of the experimental research the passage of the ultrasonic beam through modifiable layered structure in order to obtain data on changes in levels of pressure in the front slice of the acoustic field. This paper presents the spatial distribution characteristics of the acoustic field after passing the various layers in the liquid. Celebrated not only offset the propagation path, but also change the chart pressure in the front slice on the amplitude level , the width of the chart, the position of the lateral lobe and its amplitude.
Keywords: Ultrasound, layered medium, experimental assembly, refraction.
In the article are introduced research results of physicochemical properties of ammonium nitrate – potassium nitrate water system at 25o C. The literary source analysis is performed that no clear opinion about solid phases composition. The different composition double salts, solid solution and eutectics are identifies. Appeal is specifies a look and properties of formed structures. Methods of differential thermal analysis and X-ray diffraction have been establishing that the equilibrium solid phase of the studied system represents two types of solid solutions. A first type based on the III phase of ammonium nitrate crystal latitude (at the content of nitrate of potassium to 20 %) and a second type based on the potassium nitrate rhombic syngony (at the content of nitrate of potassium more than 80 %). Crystal cells parameters of being formed phases submit to the Vegard rule. The ammonium nitrate sample (at the content of nitrate of potassium more than 12 %) keeps phase stability at the temperature range minus 50 to plus 100о С. Burst in components miscibility at the potassium nitrate concentration range 30 to 80 % is observed.
Keywords: ammonium nitrate, potassium nitrate, differential thermal analysis, X-ray diffraction, cocrystallization, solid solution
The paper proposes to perform quality control of the production work on the consolidation of soil foundation with the use of the method. Application of geo-radiolocation sensing allows to specify and complement the results of engineering and geological surveys, as well as capture the changes taking place in the grounds of foundations after work on fixing them. This will provide a comprehensive picture of the grouting in the underlying foundation of the building and provide a reliable and simple quality control work.
Keywords: Geophysical methods,monitoring of the geological environment, landslide hazard.
Discusses the calculation of stress-strain State of glued structural sheathing to the test to determine the calibration of the test stand
Keywords: Finite elements method, Stress concentration, Skin, Test, Prediction.
We study the problems in the propagation of acoustic waves of a sound range near the boundaries of media. The features of the wave processes occurring at the water-air interface, due to the influence of inhomogeneous waves. Considered in detail the properties and parameters of an inhomogeneous plane wave. The mathematical calculations of the transmission coefficients L.M. Brekhovskikh for spherical and cylindrical waves through this boundary, allowing to take into account the contribution of inhomogeneous components. It is shown that than the frequency of radiation of a source is lower and the closer it is located to water-air interface, the acoustic transparency of this border is higher. Study of the dependence of the transmission coefficient of the water-air interface at low frequencies can have important consequences in a number of fundamental and applied problems. Increase the transparency of the interface requires a reassessment of the feasibility of acoustic communication from water in the air, the detection of underwater sources without dipping into the water and acoustic monitoring of the physical processes occurring in the water.
Keywords: Inhomogeneous plane wave, water-air interface, transmission coefficient, wavelength, spherical wave, acoustic impedance.
A hybrid reverberation algorithm is offered in this article. This algorithm is using both a convolution section in which a convolution with an inmpulse response of a real acoustic room is being implied and a mathematical reverb model. Also an algorithm for generating impulse responses of optional rooms is also offered in the following article. The algorithm efficiency calculation is specified in the article. Thia reverberation algorithm is a part of a bigger complez auralization algorithm where it is being used coherently with an HRTF-based algorithm in order to simulate a real acoustic environment
Keywords: artificial reverb, room simulation, convolution algorithm, impulse response convolution, impulse response synthesis, dynamic convolution, complex filtering
The problems of mm propagation: rain attenuation, depolarization and gaseous absorption are considered, and the estimate of the energy potential of wireless mobile data transport networks is given. The dependence on the output power of the distance and the total losses, and the necessary signal levels for different types of modulation being shown. The estimate of the interfering transmitters effect of side lobes of the antenna is given.
Keywords: radio wave propagation, mm range, energy potential, rain clutter, side lobes, polar pattern
To the East Donbass agglomeration has developed thematic maps of subsiding soils, indicating their capacity, groundwater levels, surface subsidence above mining, landslide and erosion hazards. Sources of information were the materials of the geological surveys, maps and literature data, and numerical modeling. For the purposes of industrial and civil construction built the final map of the cumulative effects of geological hazards.
Keywords: geological hazard, modeling, geofiltration,subsidence, landslides, erosion, underflooding, agglomeration.
To the Volgodon settlement-system has developed thematic maps of subsiding soils, indicating their capacity, groundwater levels, landslide and erosion hazards. Sources of information were the materials of the geological surveys, remote sensing of the Earth and local geological maps . Application of GIS-technologies and numerical geofiltration has significantly increased the quality of the results. On the basis of the results, has developed a comprehensive map of geological hazards.
Keywords: geological hazard, modeling, geofiltration, subsidence, landslides, erosion, underflooding, remote sensing
Solution for high-speed video transmission in hydroacoustic channel by amplitude modulation with orthogonal subcarriers is specified. Results of method experimental check are presented. Discussed method is doppler-tolerant and can be realized in many common DSPs.
Keywords: hydroacousitcs, video transmission, amplitude modulation
Analysis and evaluation of geological and hydrogeological risks is a special kind of design and survey activities aimed to provide public safety, economyfacilities and the environment within the areas exposed to dangerous geological and engineering-geological processes. The article deals withreduce environmental risksmeasures in case of dangerous geological processes. A variant of engineering-geological zoning of the urban area, depending on the state and properties of the geological environment.
Keywords: ecology, geology, risk