The kinetics of ignition in CnH2n + 2:O2:Ar mixtures for n=2 to 5 has been studied experimentally and numerically after a high-voltage nanosecond discharge. The ignition delay time behind a reflected ...shock wave was measured with and without the discharge. It was shown that the initiation of the discharge with a specific deposited energy of 10 -30 mJ/cm3 leads to an order of magnitude decrease in the ignition delay time. Discharge processes and following chain chemical reactions with energy release were simulated. The generation of atoms, radicals and excited and charged particles was numerically simulated using the measured time-resolved discharge current and electric field in the discharge phase. The calculated densities of the active particles were used as input data to simulate plasma-assisted ignition. The sensitivity of the results to variation in electron cross sections, reaction rates and radical composition was investigated. Good agreement was obtained between the calculated ignition delay times and the experimental data. The analysis of the simulation results showed that the effect of nonequilibrium plasma on the ignition delay is associated with faster development of chain reactions, due to atoms and radicals produced by the electron impact dissociation of molecules in the discharge phase. Finally, we studied the role of various hydrocarbon radicals in the plasma-assisted ignition of the mixtures under consideration.
Abstract
The paper considers the details of design and construction of a small-sized wind tunnel with an open circuit and a closed test section for investigating the blades of horizontal-axis wind ...turbines. The effect of different types of jet straighteners on the turbulence of the flow in the test section has been studied. Turbulence flow distributions Tu at Reynolds numbers Re from 5·10
3
to 2·10
4
are obtained using Laser Doppler Anemometry methods. As a result, the wind tunnel design with average flow turbulence of 1.6 % is obtained. The flow visualization of NACA 64-618 airfoil at Re = 5·10
3
is obtained.
Surfactant proteins SP-A and SP-D, members of the type C collagen-containing lectin family, are used as diagnostic and prognostic markers for many acute and chronic diseases of the bronchopulmonary ...system. The aim of the study was to assess the influence of conventional risk factors for chronic noncommunicable diseases on the level of surfactant proteins SP-A and SP-D through a system-structural analysis based on current publications from international databases and official WHO reports. Based on the results of the analytical review, it is concluded that widespread expression of SP-A and SP-D have been documented in numerous studies, and, although the lung remains the main site of the synthesis of surfactant protein, they can be expected to have a significant influence on the immune and inflammatory response in many organs and tissues. The authors note that a number of extrapulmonary effects of these proteins are known. However, many mechanisms of additional cellular effects of SP-A and SP-D outside the bronchopulmonary system still remain unexplored, which indicates the promise of further research in this area.
The paper presents a numerical simulation of the dynamics of high-velocity aluminum plasma jets with multiple injection in the Earth’s ionosphere. Scenarios of single injection, counter injection, ...and collimation of plasma jets at a given convergence angle are considered. The gas-dynamic parameters of plasma formations and their optical characteristics are determined.
Variants for complete damping of the scattered and diffraction sound field of a cylindrical shell are considered, and calculation results obtained for the diffraction field damping are presented.
Abstract
The paper investigates the flow behavior near the NACA 64-618 airfoil profile of the blade tip section of a wind turbine for electric power production after a short icing event. The flow ...simulation considering the rotation speed of the wind turbine blade is performed to assess the effect of icing on the aerodynamic characteristics. Degradation of aerodynamic characteristics affects the electrical energy production of the wind turbine. The aerodynamic lift and drag coefficients are calculated for different angles of attack. The flow velocity fields near the airfoil are analyzed. The pressure coefficient distributions along the profile surface are obtained. The points of flow stall and changes of aerodynamic characteristics at different angles of attack are determined.
Time dependences of gasdynamic parameters of the high-speed aluminum plasma jets injected into the ionosphere at altitudes 140–300 km plasma jet explosive type generators (ETG) were obtained. The ...results of numeric simulations of the initial stage of jet dynamics agree with measurement data of gasdynamic and radiation characteristics of the plasma in laboratory and ionospheric experiments.
The exact equation of sound pressure of a field irradiated by oscillating cylindrical shell submersed into a fluid has been obtained on the basis of the solution to the wave equation in cylindrical ...coordinates.
This article describes a method of calculation of forced oscillations of a compound cylindrical shell immersed into a liquid, excited jointly by discrete forces and a load distributed over the ...length. The system is comprised of cylindrical shells (compartments) connected by elastic rings.
Self-assembled InGaAs quantum dots with In content 80% grown on vicinal GaAs substrates by MOVPE method have been investigated by photoluminescence technique in a wide range of temperatures and ...excitation densities. Multimodality of distribution of size and (or) shape in array of vertically stacked quantum dots synthesized under different growth conditions as well as in a single layer structure was found on the ground of appearance of a set of peaks in photoluminescence spectra at lowered temperatures. Influence of growth conditions on density and radiation wavelength of quantum dot modes has been analyzed. Investigation of photoluminescence of samples as a function of temperatures has allowed determining activation energies of three channels of the losses that were attributed to different modes of quantum dots.
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