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he full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of 100Mo to the ground state of 100Ru, T1/2=[6.81±0.01(stat)−0.40+0.38(syst)]×1018y. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of 5×105 events and a signal-to-background ratio of ∼80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of n = 2,3,7, as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained. [ABSTRACT FROM AUTHOR]

A silica decoration methodology of Ni−Zn alloy was applied to Ni−Fe and Ni−Ga alloy to improve their activities on acetylene hydrogenation. Ni−Fe and Ni−Ga alloys were decorated by additional SiOx species by impregnation with an ethanol solution of triphenylsilanol (C18H16OSi). The results show that the degree of alloying and the size of Ni−Fe did not change as well as Ni−Ga. The catalytic activity towards Si−Ni−Fe/SiO2 and Si−Ni−Ga/SiO2 was successfully enhanced compared to the undecorated which was similar to the result that has been reported for Si−Ni−Zn/SiO2. This result proved that silica decoration methodology was effective in the improvement of Ni alloy-based catalysts. [ABSTRACT FROM AUTHOR]

Superconducting single photon detectors (SSPD or SNSPD) are excellent for detecting single photons. The principle of their operation is based on a local violation of superconductivity as a result of an absorbed photon, the formation of a hot spot with a normal domain, followed by a voltage pulse. Recent studies show that SSPDs based on micron-wide strips can also detect single photons. SSPDs can be used to distinguish between single-photon, two-photon and many-photon events by the amplitude of the voltage pulse if a proper impedance transformer is used, or by the shape of the front edge of the voltage pulse when using high frequency read-out and subsequent pulse shape analysis. However, in all cases it is considered that two photons are absorbed and form hot spots simultaneously. In a real experiment however, two photons have different optical paths and as a consequence a bit different arrival times. In this work, electrothermal simulation of the evolution of two hot spots formed with a time delay is carried out in the two-dimensional case. The possibility of distinguishing two-photon events from single-photon events is estimated for different delay values for different readout schemes. [ABSTRACT FROM AUTHOR]

It was found that a conventional oscillatory circuit, widely used to produce vibrations at frequencies used in radio broadcasting, is not suitable for generating vibrations in the centimeter wave range. Some successes have been achieved with a triode generator with a positive grid and a resonant two-wire line instead of an oscillatory circuit. Work on obtaining vibrations in the range of millimeter waves by the method of excitation of iron filings suspended in oil was carried out by scientists, but the desired results were not achieved until attention was paid to the excitation of vibrations in volumetric resonators. [ABSTRACT FROM AUTHOR]

The agro-industrial complex is an important branch of the national economy. The operation of agricultural machinery also occupies an important place in the agro-industrial complex. To ensure the efficiency of agricultural machinery with low financial costs is an urgent task. This paper presents an analysis of the problem of failure of agricultural machinery. The main reasons leading to the failure of rolling bearings are considered. The paper describes the possibility of using polymer materials to restore worn parts and to strengthen parts during their repair. Dielectric and thermophysical properties show huge values for many types of industries, electrical engineering. The dielectric properties of polymers are closely related to their molecular structure, depend on the chemical composition, on the structure of the chains. There are different methods for determining the dielectric properties of polymers: bridge, resonant, wave. Of the listed known methods for studying dielectric characteristics, the theoretical foundations of the resonance method are described in detail in this paper. The thermophysical and dielectric properties of polymer materials have been studied: polyvinyl carbazoles, polymethylmethacrylate and polymethylacrylate. Permittivity and dielectric losses have been studied in a wide range of temperatures and frequencies. The values of the dielectric permittivity are determined, the values of the activation energy of polymers are calculated using the Arrhenus formula. Thus, dielectric parameters are important characteristics of polymer materials. [ABSTRACT FROM AUTHOR]

An effective way to increase the resistance of reinforced concrete structures to the action of aggressive environments is the use of polymer composite reinforcement, in particular, glass composite reinforcement. In the scientific and technical literature, there are practically no data on the effect of the diameter and topography of the lateral surface of the glass composite reinforcement on its operational properties. The purpose of the work is to establish the influence of the diameter and topography of the lateral surface on the strength of the glass composite reinforcement. As an object of research, composite reinforcement with a diameter of 6-24 mm, manufactured by Ruscompozit (Russia), was used. The strength characteristics were determined in accordance with current standards on modern testing equipment. It is shown that with an increase in the diameter of the glass composite reinforcement, the density increases and the physical and mechanical characteristics of the reinforcement decrease. At the same time, composite reinforcement with sand coating has a higher strength compared to the glass composite reinforcement with a spiral winding. It has been established that with an increase in the ambient temperature from -60 °C to +60 °C, the strength of the glass composite reinforcement decreases. It was revealed that the chemical resistance of the glass composite reinforcement depends on the chemical nature of the aggressive environment and, to a lesser extent, on its diameter. Data on the resistance of glass composite reinforcement with sand coating and with spiral winding in an alkaline environment are given. [ABSTRACT FROM AUTHOR]

Systems of equations with delay are widely used in various fields of modern mathematical modeling. The development and implementation of effective algorithms for the numerical solution of various classes of equations with lagging arguments is an urgent task. In this article, we considered the modeling of the learning process, which are described by classes of differential equations with a lagging argument. When developing the structure of a mathematical model, it is necessary to apply the modified Runge-Kutta method, which allows for integration with a variable step and localize the points of discontinuity of derivatives. The application of sequential integration methods (step-by-step method) for solving a differential equation with a lagging argument and comparing the resulting solution with numerical methods using the Matlab software package is considered. [ABSTRACT FROM AUTHOR]

In the framework of the weakly nonlinear stability theory a mathematical modeling of the region of the nonlinear evolution of natural disturbances on an impermeable thermally insulated surface in a supersonic boundary layer was carried out for a Mach number M = 2. The first level of nonlinear interaction is investigated in the three-wave resonance systems. The main regularities of resonance interaction in single triplets composed of three-dimensional components are considered, group interaction (the joint realization of several simple triplets) is studied. The results proved to be adequate to the experimental data, which testifies to the possibility of such interaction at the initial stage of the nonlinear evolution of natural disturbances. [ABSTRACT FROM AUTHOR]

In the paper, the method of synthesis of hierarchical discrete control systems is proposed. It is applied for design of a control system for a robotic manipulator. This method allows to design sets of hierarchical regulators both for the tasks of positional control and for the trajectory execution of the manipulator's end-effector. The resulting closed-loop systems with regulators synthesized by this method are asymptotically stable relative to the desired states, invariant to external disturbances and parametrically robust. [ABSTRACT FROM AUTHOR]

The article posed the problem of assessing the significance of the input parameters of the database of patients' conditions for predicting the complications of myocardial infarction. This problem was solved using artificial neural networks modeled in Python using Keras library functions. The neural network included fully connected Dense layers and auxiliary DropOut and BathNormalization layers. Two algorithms for excluding insignificant inputs were tested - by the total weight of the input synapses of the trained network and the sparseness of the input data. The set of input columns selected in the course of computational experiments increased 20% for the accuracy indicator and 8.5% for the precision indicator compared to the original database. Thus, the chosen tools for analyzing the significance of input signals showed relatively high efficiency in solving the problem of predicting complications of myocardial infarction. [ABSTRACT FROM AUTHOR]

Concentrated products feature a longer shelf life, easier transportation because of lower weight, and a shorter recovery time. Many food products, in particular beverages, are thermolabile. When they are exposed to high temperatures, their native properties are lost, the chemical composition changes and the quality may deteriorate. Therefore, concentrates of such products benefit from low temperatures treatment. Lyophilization, or vacuum freeze-drying, allows to effectively preserve physico-chemical properties of raw materials in food concentrates and avoid high temperatures treatment. Nowadays, plant extracts are used as important additives in the food industry due to their content in biologically active substances such as polyphenolic compounds, which have antioxidant activity and play an important role in the fight against free radicals. A plant that possesses polyphenols in its chemical composition is rosehip. The article describes experiments conducted to study the effect of lyophilization on the change in physico-chemical properties of rosehip fruit extract. An analysis was carried out to evaluate the dry matter concentration, total content of polyphenolic compounds, chromaticity, turbidity and pH losses of the extract under the developed mode of lyophilization. Based on the research results, lyophilization allows to obtain the concentrated rosehip extract with a high level of preservation of the dry matter concentration, total content of polyphenols, chromaticity, turbidity and pH. [ABSTRACT FROM AUTHOR]

Farming1 is an excellent niche for automation and robotic innovations. The manual farming process deals with many repetitive and tedious tasks. It makes it perfect for applying automation through agricultural robot concepts, AGRIBOTS, which can lead to more effective and efficient farming. The AGRIBOTS can cope with various agrarian tasks such as seeding, watering, harvesting, and monitoring. One of the challenges in autonomous farming is identifying the accurate harvest time. This study addressed the challenge for carrot farms by developing an optimized Fast Library for Approximate Nearest Neighbors (FLANN) feature matching algorithm with a randomized KD-tree index and a Scale Invariant Feature Transform (SIFT) algorithm to classify carrots and weeds images. This paper proposes an autonomous, innovative farming approach for small to medium-sized enterprises (SME) with a robotic arm and a claw that can move in the x-axis and y-axis on a gantry crane to precisely automating the seeding, weeding, and harvesting processes. In addition, a web application was developed for farmers to monitor crops conditions such as humidity, temperature, and soil moisture in real-time. They can also observe the whole automated process of planting with the growing period of the corps on the calendar. Finally, a prototype was built and tested successfully to evaluate the overall performance of the proposed AGRIBOT. Over one hundred samples were used to train the classification model that reached the Percentage of Correct Classification (PCC) of 77% and the precision of 88%. [ABSTRACT FROM AUTHOR]

Analytical modelling of composite structures is found to be difficult to develop especially to predict the structural vibration responses due to the complicated of components itself such as matrix-reinforcement element, fibre orientation and unknown properties fibre raw material during fabrication stages of composite structures. The uncertainties of the finish product of components then indirectly affect the initial analytical model of the composites in comparison to measured vibration responses. Therefore, this paper aim to investigate the accuracy of analytical model of composite structure using finite element (FE) method. There are two methods that been investigated in this work by implemented MSC Patran/Nastran software which are simplified shell element property card (PSHELL) and complicated layered composite element property card (PCOMP). The accuracy of the both models are compared with experimental results obtained by using experimental modal analysis (EMA). Then, FE model updating was utilized to enhance the quality of analytical models. The results show that the PSHELL model provide the simplest technique in composite structure modelling, however PSHELL providing inaccurate prediction especially when the model required optimisation steps. Meanwhile, good achievement in term of prediction accuracy can be achieved by utilising the PCOMP model. However, complexity of the PCOMP modelling technique could become cumbersome in the large and more complex geometry structure due to it requirement to define all the properties of plies. [ABSTRACT FROM AUTHOR]

An important parameter for casting in-place concrete in hot climate conditions is the concrete mix initial temperature. The concrete mix temperature factor defines, to large extent, the parameters of non-homogeneous thermal field of the hardening mass reinforced concrete structure, which has a significant impact on its final quality. In addition, an excessively high temperature of the concrete mixture promotes to a rapid decrease of the concrete mixture mobility, which leads to difficulties in laying it into the structure. The article considers and analyzes the possible methods of reduction of the temperature of raw materials for concrete and concrete mix: cooling of water and of other concrete mix components, application of flaky ice in process of concrete mix preparation, cooling the concrete mixture using liquid nitrogen directly in the drum of the concrete mixer after loading it from the concrete mixing plant. Based on the results of analytical investigations the most effective methods of reduction of initial temperature of concrete mix for various types of hot climate conditions were defined. [ABSTRACT FROM AUTHOR]

An experimental study is carried out of the deformation process of the samples of siltstone and limestone with joints under direct shear with constant compressive load. The values of the degree of water saturation and the roughness coefficient of surfaces of joints varied. The aim of the work was to study the character of changes of the parameters of microseismic emission signals depending on the degree of water saturation and the roughness coefficient of the samples under direct shear loading. The first signals of microseismic emission appear at the stresses of 0.3–0.4 of the shear strength for the siltstone samples with high surface roughness values. The number of signals increases at the maximum load value and remains significant until the residual strength section. The highest values of the acceleration amplitude correspond to the break-downing of high roughness peaks. The direct shift occurs during monotonous sliding without sharply pronounced damage for limestone samples that are in a completely water-saturated state. It is confirmed by the absence of significant changes of the characteristics of microseismic emission signals. [ABSTRACT FROM AUTHOR]

A new approach to the problem of odometric positioning of a mining machine under the ground is proposed. As a technical solution to the task, the use of BLE (Bluetooth Low Energy) technology is proposed. Bluetooth beacons will be dropped as the combine moves. A sensor attached to the back of the transfer hopper will measure the distance to the nearest beacon. A model is created that simulates random speeds of the combine's movement on sections of random length. Random dispersion when dropping Bluetooth beacons is simulated. To generate sensor measurements, an algorithm is being developed that takes into account the increase in the error of readings when moving away from the nearest dropped beacon. To process the simulated measurements and correctly determine the distance, the Kalman filtering algorithm is used. The proposed approach and the created simulation model allow, with a given degree of accuracy, to determine and predict the distance to the mining machine during the development of industrial seams. [ABSTRACT FROM AUTHOR]

The Arctic attracts the attention of many countries of the world, as it is rich in hydrocarbons. The polar people are faced with the problem of providing electricity. Traditionally, diesel generators are used in the Arctic, while electricity is costly, and the generators themselves pollute the environment. Many researchers use wind generators and solar power plants. Wind generators do not withstand severe frosts and strong winds. This study is devoted to the problem of choosing the type of solar cells that could work efficiently at low temperatures. [ABSTRACT FROM AUTHOR]

The features of nucleation, start, and propagation of a crack inside a transparent organic sample are investigated. The distribution of the refractive index and density around the crack was studied by changing of speckle images and ellipsometry method. It was found that the maximum value of the relative change in density is near the crack. This value before the crack start is greater than 0.003. It is proved that the speckle method we offer can be the basis for the creation of various techniques. Using these techniques will allow us to estimate the time before the crack start by the rate of change of physical quantities in small areas of the order of 50 µm and their limiting values. The results of experimental investigations are presented. [ABSTRACT FROM AUTHOR]

Investigations of the excitation and development of contrarotating longitudinal vortices in a supersonic boundary layer of a flat plate are considered in this paper. The experimental study was conducted on the model of blunt flat plate at Mach 2 and unit Reynolds number Re1=8×106 m-1. Vortices in the boundary layer of the model were generated by weak shock waves from a pair of 2D-irregularities on the walls of the wind tunnel test section. The measurements were performed by a constant-temperature anemometer. According to the experimental conditions, the interaction of longitudinal vortices is not observed. Spectral and statistical data analysis showed that longitudinal vortices do not lead to a laminar-turbulent transition in the measuring area. [ABSTRACT FROM AUTHOR]

The non-linear development of the slow and fast supersonic instabilities and their mutual interactions are studied in the mixing layer at the convective Mach number Mc=4 with the numerical simulation. Spatial evolution of the instability is considered. The unstable waves are excited at the inflow boundary in the form of linear stability eigenfunctions. The simulation results show that the disturbance of the slow mode grows rapidly at the initial stage and reaches a nonlinear development regime with the formation of vortex structures in the form of curls in the lower critical layer. The development of the fast-mode disturbance at the initial stage is much slower. The disturbance gradually reaches the regime of nonlinear growth with the formation of elongated vortex structures in the upper critical layer. In both cases, intensive radiation of waves in the external streams is observed. [ABSTRACT FROM AUTHOR]

The results of an experimental study of the perturbation development created by pulsed glow discharge on the swept wing surface with periodic distributed roughness along the leading edge at Mach 2 are presented. The influence of periodic roughness on the model surface on the excitation and development of wide-spectrum disturbances in the process of laminar-turbulent transition is determined. It was found that the mean flow modulation in the boundary layer of a swept wing with a sweep angle of 40 degrees leads to a strengthening of the oblique breakdown mechanism. [ABSTRACT FROM AUTHOR]

The NA62 experiment at CERN Super Proton Synchrotron was designed to measure BR(K+ → π+ν v ¯) with an in-fight technique, never used before for this measurement. This decay is characterised by a very precise prediction in the Standard Model. Its branching ratio, which is expected to be less than 10−10, is one of the best candidates to indicate indirect effects of new physics beyond SM at the highest mass scales. NA62 result on K+ → π+ν v ¯ from the full 2016 data set is described. Also a search for an invisible dark photon A′ has been performed, exploiting the efficient photon-veto capability and high resolution tracking of the NA62. The signal stems from the chain K+ → π+π0 followed by π0 → A′γ. No significant statistical excess has been identified. Upper limits on the dark photon coupling to the ordinary photon as a function of the dark photon mass have been set, improving on the previous limits over the mass range 60 - 110 MeV/c2. [ABSTRACT FROM AUTHOR]

The present paper reports on a combined application of time-resolved stereoscopic particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) methods to measure flow and temperature fields in a submerged swirling water jet, impinged normally on a flat heated surface. Simultaneously, the impingement surface temperature was monitored via high-speed IR-imaging. A multi-frame PIV algorithm was used to process the PIV images. A number of image filtering routines, including spatial and temporal filtering, was necessary to obtain a reliable accuracy of the temperature evaluation from the PLIF snapshots. Difference between the temperature of the liquid in vicinity of the wall and wall temperature, evaluated correspondingly from the PLIF and IR imaging, is found to be below 1°C. [ABSTRACT FROM AUTHOR]

We suggest using the spectral form of mathematical description, or the spectral method, for the statistical analysis of stochastic jump diffusion systems, i.e., for solving the Kolmogorov–Feller equation for the probability density of the system state vector. The spectral form of mathematical description allows to transform linear partial differential equations or partial integro-differential equations into a system of linear algebraic equations, which determines coefficients according to orthogonal series expansions for the probability density with respect to an arbitrary orthonormal system of functions. As an example for testing the proposed method, the modified Dryden wind turbulence model, allowing to take into account not only continuous random effects, but also impulse ones, is considered. [ABSTRACT FROM AUTHOR]

The purpose of this laboratory study was to determine the regularities of deformation process of rock samples with joints under three-stage direct shear loading. The tests were carried out under the boundary condition “constant normal load” (CNL) at three values of normal compressive stress: 0.3, 0.6 and 0.9 MPa. Special test bench was developed and created on the base of servo-hydraulic press Instron 8802 for shear loading of rock samples according to ASTM D 5607 standard. The research demonstrated that the character of the deformation process of rock joints is essentially determined by the value of surface roughness coefficient under direct shear loading. The features of shear deformation are analyzed for three group of samples with different values of the roughness coefficient. The value of cohesion increases as the roughness coefficient increases. The angle of internal friction increases with increasing roughness value, however, these changes are minor. [ABSTRACT FROM AUTHOR]

The effect of the GT-resonance structure of charge-exchange strength function in the 76Ge(³He,t)76As reaction on the solar neutrino capture cross section was examined. It is shown that accounting of GT-resonances increase solar neutrino capture rate more then 20%. Theoretical strength functions for 76Ge and 74Ge were calculated in accordance with the framework of the self-consistent theory of finite Fermi systems. This results could help to decompose experimental strength function and itemize some low-lying excitation states and pygmy resonances. Also we demonstrate significant role of quenching effect for cross section calculations. Accurate counting of neutrino capture rate could change estimations on background events index in experiments on double beta decay search (like LEGEND). [ABSTRACT FROM AUTHOR]

Experimental studies of the effect of a weak wave from the ledge of two-dimensional roughness installed on the side wall of the test section of the wind tunnel on the supersonic boundary layer of the blunted flat plate at the Mach number 2.5 was carried out. The measurements were performed by a constant temperature hot-wire anemometer in the region of stream wise vortices generated by the wave from the ledge during interaction with the flow in the vicinity of the leading edge of the model. The spectral and statistical analysis of the measured disturbances in the boundary layer was carried out. The amplitude-frequency spectra of mass flow pulsations and statistical diagrams of the measured disturbances in the supersonic part of the boundary layer were obtained. [ABSTRACT FROM AUTHOR]

Three samples of vertical-cavity surface-emitting laser diodes (VCSEL) designed by Vixar Inc. are studied. The central wavelength of the lasers is about 894.6 nm (D1 line of cesium). The threshold currents of laser generation are measured. The laser injection current is modulated at microwave frequency about 4.596 GHz that is a half of Cs groundstate hyperfine splitting frequency. Dependence of phase modulation index of laser radiation on microwave power is determined. The observed deviations of laser properties from sample to sample are compared to other works. A particular attention is paid to observation of additional optical frequencies (ghost modes) in the laser spectra, having the same polarization as the main spectral sidebands. This effect can harm metrological characteristics of various quantum devices where VSCELs are nowadays used. The optimal regimes of laser performance to avoid generation of the ghost modes are found. Also, asymmetry of the spectra caused by a residual amplitude modulation is measured. The results can be important for creation of various VCSEL-based quantum devices (atomic clocks, magnetometers). [ABSTRACT FROM AUTHOR]

In recent years, fresh fruits and vegetables have been linked to numerous foodborne illnesses. Escherichia coli can be one of the pathogens which cause these diseases and outbreaks to consumers through consumption of contaminated food. A study was conducted to understand the probability of bacterial transfer in soil and barley leaves. E. coli from contaminated irrigation water was applied to sterilized barley seeds which grown in the laboratory. Two agriculture types, sterilized organic soil, and cotton pillow with drip irrigation method for plants cultivation. The results showed bacterial contamination of organic soil and cotton pillow. However, the organic soil was contaminated higher than a cotton pillow because it is rich in organic matter, and organic matter can carry bacteria. For barley leaves, the result showed no contamination by E. coli for seeds which grow on the cotton pillow, but leaves which grown on organic soil, there was contamination by E. coli. The study can be approved that bacteria may have gotten transported to the leaves through the root system, xylem, and phloem. [ABSTRACT FROM AUTHOR]

This article discusses the use of different wavelet functions for speech analysis. The analysis of oral speech in the Yakut language is given. Examples of speech segmentation using wavelet functions are given. The problems of segmentation of traditional sounds of the Yakut speech are considered, combinations of sounds of poorly segmenting are revealed. Phonetic attributes of sounds of the Yakut language are given, the reasons of incorrect segmentation are considered. [ABSTRACT FROM AUTHOR]

The present paper reports on the measurements of flow structure and heat transfer in swirling jets, impinging normally on a flat heated wall. Velocity field is measured by using the stereoscopic particle image velocimetry technique, whereas the wall temperature is monitored by IR imaging. Two cases of distances between the jet nozzle and impingement surface are considered, namely, one and two nozzle diameters. The Reynolds number is fixed as Re = 5000. Flows of nonswirling, weakly and strongly swirling jets are investigated. Only for the latter case in free jet flow configuration, the swirl intensity exceeds a critical value for breakdown of the swirling jet's vortex core, corresponding to the formation of a central recirculation zone. For the confined jet conditions, the superimposed swirl in both cases results in presence of an extended recirculation zone between the nozzle and impingement wall, which is found to reduce heat transfer around the stagnation point for the separation distance of two nozzle diameters. However, for the separation distance of one nozzle diameter, the high-swirl jet is found to provide most effective overall cooling of the wall. [ABSTRACT FROM AUTHOR]

This study outlines the results of experimental research on flow parameters (flow angularity and static pressure) near a perforated wall using a six-hole probe located on the wall of T-128 wind tunnel test section in the area of significant perturbation caused by the model. In test section 1 the probe was set on the upper and lower walls (during the tests of a full-scale model); in test section 2 - on the side wall (during the tests of a half model). The perforation ratio varied from f=2% to f=10%. The distance between the perforated wall and the probe varied from 70 mm to 200 mm in order to detect the position where the probe is above the boundary layer. Technique to process acquired experimental data and to determine porosity coefficient R was developed and described in detail. A particular care was taken to study perforation f=6% since it is considered as an optimality state in terms of minimizing flow boundary interference in subsonic tests. All the measurements were made during industrial tests of various models in a wide range of subsonic speeds 0.2≤М≤0.95. The introduction includes the review of works on the topic. The study provides examples of flow computation near perforated walls of wind tunnel test section for the tests of flight vehicle models using acquired boundary condition parameters. [ABSTRACT FROM AUTHOR]

The problem of the laminar-turbulent transition control on flight vehicle elements has multiple application aspects: the friction drag reduction, modeling of natural flow conditions in wind tunnels, the elimination of the symmetric separated flow instability, the decrease of heat fluxes in hypersonic flows and others problems. W. Pffeninger indicated the possible improvement of the total flow structure due to the boundary layer laminarization. In some cases the laminar-turbulent location change can influence negatively on the total flow structure. In present report, different examples showing the importance of the transition mechanisms analysis and the analysis of all control consequences for different flow types from subsonic to hypersonic velocities. [ABSTRACT FROM AUTHOR]

Now a day’s rocket engines (air-breathing type) are being used for aerospace purposes but the studies have shown that these are less efficient, so alternatives are being searched for these. Pulse Detonation Engine (PDE) is one such efficient engine which can replace the rocket engines. In this review paper, different researches have been cited. As can be observed from various researches, insertion of obstacles is better. Deflagration to Detonation(DDT) transition process is found to be most important factor. So a lot of researches are being done considering this DDT chamber. Also, the ignition chamber and ejector were found to improve the effectiveness of PDE. The PDE works with a range of Mach 0-4. Flame acceleration is also found to increase the DDT process. Use of valve and valveless engine has also been compared. Various other factors have been focused in this review paper which is found to boost PDE performance. [ABSTRACT FROM AUTHOR]

A mathematical model is considered for the determination of the surface charge of an erythrocyte with its shape approximated by a surface of revolution of the second order, and the investigation of the dynamics of erythrocytes under the influence of an external electric field. In the first part of this work, the electrical surface charge of the erythrocyte of the patient was calculated with the assumption that the change in the shape and size of the red blood cells leads to stabilization of the electric field, providing a normal electrostatic repulsion. In the second part of the work, the research results of dynamics of changes in the morphology of erythrocytes under the influence of an external electric field depending on the values of their surface charge and resistance of blood plasma is presented. In the course of the work, the dependence of the surface charge of red blood cells from their shape and size is presented. The determination of the relationship between the value of the charge field and the surface of erythrocytes in norm and in pathology is shown. The dependence of the velocity of the erythrocytes on the characteristics of the external electric field, surface charge of the erythrocyte and properties of the medium is obtained. The results of this study can be applied indirectly to diagnose diseases and to develop recommendations for experimental studies of hemodynamics under the influence of various external physical factors. [ABSTRACT FROM AUTHOR]

The results of an experimental study of the controlled pulsations development in the spanwise modulated boundary layer of a swept wing are presented in the paper. The experiments were conducted at Mach 2 and unit Reynolds number Re1 = 6×106 m-1. The square stickers were applied to induce the spanwise modulation of mean flow in the boundary layer. It was obtained, that the presence of roughness leads to a decrease of the disturbance source efficiency at the subharmonic and fundamental frequency, and the oblique breakdown mechanism begins to appear at smaller values of the longitudinal coordinate x as compared with the case of a smooth wing. [ABSTRACT FROM AUTHOR]

Experimental data on the nonlinear wave train development in 3D supersonic boundary layer over a 45° sweptwing at Mach number 2 are presented. Travelling artificial disturbances were introduced in the boundary layer by periodical glow discharge at frequencies 10 and 20 kHz. The appearance of additional peaks in β'-spectra for subharmonic frequency is shown. The experiments indicate the presence of asymmetric subharmonic resonance mechanism in 3D supersonic boundary layer. The method of finding resonant triads demonstrate the presence of several three-wave triads in a wide range of transverse wave numbers for the fundamental frequency. [ABSTRACT FROM AUTHOR]

The author of this article manages a project and research activity of students in the areas of computer science, physics, engineering and biology, basing on the acquired experience in these fields. Pupils constantly become winners of competitions and conferences of different levels, for example, three of the finalists of Intel ISEF in 2013 in Phoenix (Arizona, USA) and in 2014 in Los Angeles (California, USA). In 2013 A. Makarychev received the "Small Nobel prize" in Computer Science section and special award sponsors - the company's CAST. Scientific themes and methods suggested by the author and developed in joint publications of students from Russia, Germany and Austria are the patents for invention and certificates for registration in the ROSPATENT. The article presents the results of the implementation of specific software and hardware systems in physics, engineering and medicine. [ABSTRACT FROM AUTHOR]

The paper presents the results of magnetoelastic testing of ferromagnetic steel. The power-law nature of the relaxation of the residual magnetization of the specimen has been detected. Close to the fatigue limit, the parameters of the power-law approximation show some features. [ABSTRACT FROM AUTHOR]

We consider the applicability of laser transillumination method for the investigation of the screech-tones generation by the supersonic jet. Results of the experiments on parallel registration of the acoustic noise and laser radiation passed through the jet are discussed. The presence of responses at screech frequencies are found in the radiation spectra. Strong dependence of spectral amplitudes at screech frequencies from the sensing path shows high sensibility of laser sensing method for the selection of jet areas producing screech. [ABSTRACT FROM AUTHOR]

The paper presented the results on the generation and development of the wave train in spanwise modulated supersonic boundary layer at Mach 2 and 2.5, which obtained experimentally in the same conditions of controlled experiment. In experiments on the flat plate with roughness it was obtained that at the Mach number M = 2.5 both a subharmonic and fundamental wave packet develops almost linearly, whereas at the Mach number M = 2.0 there is competition between the two mechanisms of unstable waves interaction. It was obtained that in the boundary layer on swept wing the roughness presence can leads to the stabilization of the wave packet development at fundamental and subharmonic frequency in the downstream direction. [ABSTRACT FROM AUTHOR]