bluuebunny/crossref_metadata_2025 huggingface dataset:
Transparent metal-oxide nanowires and their applications in harsh electronics
Authors: Zhou Ziyao , Lan Changyong , Wei Renjie , Ho Johnny C.
Published: November 2018

This work provides a comprehensive review of the recent advances in high-performance transparent metal-oxide nanowires and their corresponding device applications in harsh electronics.
The transverse thermoelectric effect in a-axis inclined oriented SnSe thin films
Authors: Hou Shuaihang , Yuan Dachao , Yan Guoying , Wang Jianglong , Liang Baolai , Fu Guangsheng , Wang Shufang
Published: November 2018

The transverse thermoelectric effect has been first observed in a-axis inclined oriented SnSe thin films.
A small-molecule acceptor incorporating a silicon bridging atom for efficient nonfullerene polymer solar cells
Authors: Zeng Guang , Ouyang Jinyang , Xin Yue , Zhao Xiaoli , Yang Xiaoniu
Published: November 2018

The acceptor Si4TIC-F, which incorporated a silicon bridging atom, was synthesized and gave a PCE of 10.20% with the donor PBTIBDTT.
Novel hole blocking materials based on 2,6-disubstituted dibenzo[b,d]furan and dibenzo[b,d]thiophene segments for high-performance blue phosphorescent organic light-emitting diodes
Authors: Jang Seokhoon , Lee Kyung Hyung , Lee Jun Yeob , Lee Youngu
Published: November 2018

Novel hole blocking materials based on 2,6-disubstituted dibenzo[b,d]furan and dibenzo[b,d]thiophene segments have been successfully synthesized and characterized for high-performance blue phosphorescent organic light-emitting diodes.
The LoTSS view of radio AGN in the local Universe
Authors: Sabater J. , Best P. N. , Hardcastle M. J. , Shimwell T. W. , Tasse C. , Williams W. L. , Brüggen M. , Cochrane R. K. , Croston J. H. , de Gasperin F. , Duncan K. J. , Gürkan G. , Mechev A. P. , Morabito L. K. , Prandoni I. , Röttgering H. J. A. , Smith D. J. B. , Harwood J. J. , Mingo B. , Mooney S. , Saxena A.
Published: November 2018

This paper presents a study of the local radio source population, by cross-comparing the data from the first data release (DR1) of the LOFAR Two-Metre Sky Survey (LoTSS) with the Sloan Digital Sky Survey (SDSS) DR7 main galaxy spectroscopic sample. The LoTSS DR1 provides deep data (median rms noise of 71 μJy at 150 MHz) over 424 square degrees of sky, which is sufficient to detect 10 615 (32 per cent) of the SDSS galaxies over this sky area. An improved method to separate active galactic nuclei (AGN) accurately from sources with radio emission powered by star formation (SF) is developed and applied, leading to a sample of 2121 local (z < 0.3) radio AGN. The local 150 MHz luminosity function is derived for radio AGN and SF galaxies separately, and the good agreement with previous studies at 1.4 GHz suggests that the separation method presented is robust. The prevalence of radio AGN activity is confirmed to show a strong dependence on both stellar and black hole masses, remarkably reaching a fraction of 100 per cent of the most massive galaxies (> 1011 M⊙) displaying radio-AGN activity with L150 MHz ≥ 1021 W Hz−1; thus, the most massive galaxies are always switched on at some level. The results allow the full Eddington-scaled accretion rate distribution (a proxy for the duty cycle) to be probed for massive galaxies, and this accretion rate is found to peak at Lmech/LEdd ≈ 10−5. More than 50 per cent of the energy is released during the ≤2 per cent of the time spent at the highest accretion rates, Lmech/LEdd > 10−2.5. Stellar mass is shown to be a more important driver of radio-AGN activity than black hole mass, suggesting a possible connection between the fuelling gas and the surrounding halo. This result is in line with models in which these radio AGN are essential for maintaining the quenched state of galaxies at the centres of hot gas haloes.
Combining multiple structural inversions to constrain the solar modelling problem
Authors: Buldgen G. , Salmon S. J. A. J. , Noels A. , Scuflaire R. , Montalban J. , Baturin V. A. , Eggenberger P. , Gryaznov V. K. , Iosilevskiy I. L. , Meynet G. , Chaplin W. J. , Miglio A. , Oreshina A. V. , Richard O. , Starostin A. N.
Published: November 2018

Context. The Sun is the most studied of all stars, which serves as a reference for all other observed stars in the Universe. Furthermore, it also serves the role of a privileged laboratory of fundamental physics and can help us better understand processes occuring in conditions irreproducible on Earth. However, our understanding of our star is currently lessened by the so-called solar modelling problem, resulting from comparisons of theoretical solar models to helioseismic constraints. These discrepancies can stem from various causes, such as the radiative opacities, the equation of state as well as the mixing of the chemical elements.

Aims. By analysing the potential of combining information from multiple seismic inversions, our aim is to help disentangle the origins of the solar modelling problem.

Methods. We combined inversions of the adiabatic sound speed, an entropy proxy and the Ledoux discriminant with other constraints such as the position of the base of the convective zone and the photospheric helium abundance. First, we tested various combinations of standard ingredients available for solar modelling such as abundance tables, equation of state, formalism for convection and diffusion and opacity tables. Second, we studied the diagnostic potential of the inversions on models including ad hoc modifications of the opacity profile and additional mixing below the convective envelope.

Results. We show that combining inversions provides stringent constraints on the required modifications to the solar ingredients, far beyond what can be achieved from sound speed inversions alone. We constrain the form and amplitude of the opacity increase required in solar models and show that a 15% increase at log T = 6.35 provides a significant improvement, but is insufficient on its own. A more global increase in the opacity, within the uncertainties of the current tables, coupled with a localized additional mixing at the bottom of the convective zone provides the best agreement for low-metallicity models. We show that high-metallicity models do not satisfy all the inversion results. We conclude that the solar modelling problem likely occurs from multiple small contributors, as other ingredients such as the equation of state or the formalism of convection can induce small but significant changes in the models and that using phase shift analyses combined with our approach is the next step for a better understanding of the inaccuracies of solar models just below the convective envelope.
Electron-impact double ionization of the carbon atom
Authors: Jonauskas Valdas
Published: November 2018

Electron-impact single- and double-ionization cross sections and Maxwellian rate coefficients are presented for the carbon atom. Scaling factors are introduced for the electron-impact excitation and ionization cross sections obtained in the distorted wave (DW) approximation. It is shown that the scaled DW cross sections provide good agreement with measurements for the single ionization of the C atom and C1+ion. The direct double-ionization (DDI) process is studied using a multi-step approach. Ionization–ionization, excitation–ionization–ionization, and ionization–excitation–ionization branches are analyzed. It is demonstrated that the three-step processes contribute ≼40% of the total DDI cross sections for the case where one of the electrons takes all of the excess energy after the first ionization process.
Design of Network to Monitor Infrasound from Thunderstorm Events: Development of Sensor
Authors: Kudin Dmitriy , Kudryavtsev Nikolay , Uchaikin Evgeniy
Published: November 2018

This paper describes the implementation of the autonomous infrasonic sensor for thunderstorm events recognition. Original hardware – microcontroller system with microphones, GPS-based time synchronization and GPRS-modem data transmission is described. The characteristics as calibration results is reviewed.
Ionosphere disturbance during cosmodrome “Vostochniy” launches
Authors: Dumbrava Zinaida F. , Sivokon Vladimir P. , Teslyuk Yuriy A. , Khomutov Sergey Y.
Published: November 2018

It is known that during spacecraft launches ionospheric plasma properties are modified in the result of impact of shock-acoustic waves generated during carrier rocket supersonic motion. As a rule, investigation of ionospheric plasma variations is carried out by the signals of Global Navigation Satellite Systems GPS/GLONASS that implies ground station network. There is no such a system near the “Vostochniy” cosmodrome that makes it necessary to search for an alternative solution. One of them may be the application of ionosphere vertical and oblique sounding stations. Based on the analysis of such station data, the possibility of evaluation of ionosphere modification during “Vostochniy” cosmodrome launches is shown.
Ionospheric plasma irregularities studied with Swarm satellites
Authors: Miloch Wojciech J. , Jin Yaqi , Xiong Chao , Kervalishvili Guram , Spicher Andres , Clausen Lasse B.N. , Stolle Claudia
Published: November 2018

To study and characterise the ionospheric plasma irregularities at all latitudes, one can employ in-situ measurements by satellites in polar orbits, such as the European Space Agency’s Swarm mission. Based on the Swarm data, we have developed the Ionospheric Plasma IRregularities (IPIR) product for a global characterisation of ionospheric irregularities along the satellite track at all latitudes. This new Level-2 data product combines complementary datasets from the Swarm satellites: the electron density from the electric field instrument, the GPS data from the onboard GPS receiver, and the magnetic field data from the onboard magnetometers. This can be used as a new tool for global studies of ionospheric irregularities and turbulence.
Lidar diagnostics of ionosphere precipitations
Authors: Shevtsov Boris , Perezhogin Andrey , Seredkin Ilya
Published: November 2018

Lidar is considered as an electron energy detector of ionosphere precipitations, and the cleaning of radiation belts is like the energy pumping of the ionosphere layer. The excitation efficiency of ionosphere plasma components by precipitations and the features of resonant backscattering of laser radiation in the active ionosphere are discussed. It is shown that in the quantum system in which the lidar plays the role of a master oscillator and the ionosphere layer of the amplifier, different modes of nonlinear oscillations are possible depending on the intensity of the precipitation. Analogies are being made with other natural nonlinear systems.
Recording of atmospheric electrical potential gradient in the central part of Kamchatka peninsula
Authors: Akbashev Rinat , Firstov Pavel , Cherneva Nina
Published: November 2018

Electrostatic fluxmeters are in operation at three sites in the region of Central Kamchatka depression to record the atmospheric electrical potential gradient (PG). PG diurnal variations for these sites are compared with those of «Paratunka» observatory (PRT) located on the Eastern coast of Kamchatka peninsula. Cases of the response in AEV V′ dynamics on eruptive cloud passage, occurring during Shiveluch volcano explosive eruptions, are described. Negative polarity signals with the maximum values up to 5 kV/m were recorded in the near-field zone (< 50 km) during ash fall. Positive polarity signals were recorded in the far-field zone (> 100 km). Recording of signals in PG occurring during eruptive cloud passage may be one of the components of complex observations over volcanic eruptions.
The study of chaotic and regular regimes of the fractal oscillators FitzHugh-Nagumo
Authors: Lipko Olga , Parovik Roman
Published: November 2018

In this paper we study the conditions for the existence of chaotic and regular oscillatory regimes of the hereditary oscillator FitzHugh-Nagumo (FHN), a mathematical model for the propagation of a nerve impulse in a membrane. To achieve this goal, using the non-local explicit finite-difference scheme and Wolf’s algorithm with the Gram-Schmidt orthogonalization procedure and the spectra of the maximum Lyapunov exponents were also constructed depending on the values of the control parameters of the model of the FHN. The results of the calculations showed that there are spectra of maximum Lyapunov exponents both with positive values and with negative values. The results of the calculations were also confirmed with the help of oscillograms and phase trajectories, which indicates the possibility of the existence of both chaotic attractors and limit cycles.
Using symbolic calculations to calculate the eigenmodes of the free damping of a geomagnetic field
Authors: Vodinchar Gleb
Published: November 2018

The method for calculating the eigenmodes of free damped oscillations of the geomagnetic field in the Earth’s core using symbolic computations is described.
Analysis of the efficiency of earthquake prediction based on the anomalous behavior of ionospheric parameters on the eve of earthquakes in the Kamchatka region
Authors: Bogdanov Vadim , Pavlov Aleksey
Published: November 2018

A method is presented for short-term prediction of strong earthquakes, in which the precursors are considered the excess of current values of foF2 critical frequency of the ionospheric F2 layer over the median values in periods of perturbed state of the magnetosphere, the appearance of ionospheric disturbances: K-layer, Es-spread F-spread, the stratification of the F2 layer, Es is the r type. As predicted earthquakes were considered earthquakes with magnitudes M ≥ 5:0. Assessment of the effectiveness of the forecast was carried out in the spring and autumn periods for 2013–2017 according to the methods of A. A. Gusev and G. M. Molchan. It is shown that the method under consideration has the best prognostic efficiency for seismic events with M ≥ 6:5 magnitude.
A comparison of three parameter estimation methods of the gamma distribution of annual maximum low flow duration and deficit in the Upper Vistula catchment (Poland)
Authors: Baran-Gurgul Katarzyna
Published: November 2018

Based on 30-year 24-hour flow sequences at 69 water gauging stations in the Upper Vistula catchment, it was determined that the probability distributions of the low flow duration and its maximum annual deficit can be described by the gamma distribution with the estimated parameters by the methods: MOM, the method of moments, LMOM, the method of linear moments, and MLE, the method of maximum likelihood. The stationarity of the time series was tested by the Mann-Kendall correlation using the Hamed and Rao variance correction. The low flows were defined by the SPA method, with the limit flowQ70%. The quality of the match was tested by the Anderson-Darling goodness of fit test. This test allowed accepting the gamma distribution in all analysed cases, regardless of the method used to estimate the distribution parameters, since thepv(p-values) values were greater than 5% (over 18% forTmaxand 7.5% forVmax). The highestpvvalues for individual water gauging stations, as well as the highest 90%TmaxandVmaxquantiles were noted using LMOM to estimate the gamma distribution parameters. The highest 90%TmaxandVmaxquantiles were observed in the uppermost part of the studied area.
Probabilistic analysis of coincident sums of precipitation at two measurement stations. Introduction to the method and an example
Authors: Biel Gabriela
Published: November 2018

This article proposes the use of copula (copula function) for the purpose of two-dimensional analysis of the sums of precipitation as measured with a Hellman rain-gauge. The sums of precipitation are characterized by a two-dimensional random variable: the sum of uninterrupted sequence of rainfalls which were measured in Jelcz-Laskowice and the corresponding (coincident) sum of precipitation at the Botanical Garden in Wrocław. Several problems occur from the very start: debonding from time and lack of precipitation on one of stations. For the purpose of greater precision and correction it should be stated that in order to apply the two-dimensional copula functions we will use a random vector determining the sum of uninterrupted sequences of rainfalls at two simultaneous stations. In that way, this will not be a characteristics of the phenomenon, but rather the definition of two-dimensional random variable under analysis. Data for analysis has been derived from observational logs of the Institute of Meteorology and Water Management, branch in Wrocław. The results obtained in years 1980-2014 were subject to analysis. The aim of the work was to find the best two-dimensional probability distribution of a random variable (OpadJelcz, OpadOgród). The following were analysed from among the known copulas: the Archimedean copulas (the Gumbel copula, the Frank copula and the Clayton copula) and the Gaussian elliptical copula. The study of fitting of copulas to observed variables was carried out using the Spearmann's rank correlation coefficient and the best fitting was obtained for the Frank's copula.
On using nonparametric approaches for precipitation estimation
Authors: Grządziel Mariusz
Published: November 2018

Nonparametric density estimation methods have been used for precipitation estimation for decades. The new approach for estimating the density proposed recently by Geenens and Wang appears to offer advantages over them as far as their behavior in the tail is concerned. Real data analyses presented in this paper confirm the usefulness of this new approach for precipitation modelling.
Residuals in the modelling of pollution concentration depending on meteorological conditions and traffic flow, employing decision trees
Authors: Kamińska Joanna A.
Published: November 2018

Two data mining methods – a random forest and boosted regression trees – were used to model values of roadside air pollution depending on meteorological conditions and traffic flow, using the example of data obtained in the city of Wrocław in the years 2015–2016. Eight explanatory variables – five continuous and three categorical – were considered in the models. A comparison was made of the quality of the fit of the models to empirical data. Commonly used goodness-of-fit measures did not imply a significant preference for either of the methods. Residual analysis was also performed; this showed boosted regression trees to be a more effective method for predicting typical values in the modelling of NO2, NOx and PM2.5, while the random forest method leads to smaller errors when predicting peaks.
The study and comparison of one-dimensional kernel estimators – a new approach. Part 2. A hydrology case study
Authors: Karczewski Maciej , Michalski Andrzej
Published: November 2018

The main purpose of this article is to present the numerical consequences of selected methods of kernel estimation, using the example of empirical data from a hydrological experiment [1, 2]. In the construction of kernel estimators we used two types of kernels – Gaussian and Epanechnikov – and several methods of selecting the optimal smoothing bandwidth (see Part 1), based on various statistical and analytical conditions [3–6]. Further analysis of the properties of kernel estimators is limited to eight characteristic estimators. To assess the effectiveness of the considered estimates and their similarity, we applied the distance measure of Marczewski and Steinhaus [7]. Theoretical and numerical considerations enable the development of an algorithm for the selection of locally most effective kernel estimators.
Reaction rate coefficient k20 and temperature coefficient Θ in organic waste thermal disintegration
Authors: Myszograj Sylwia
Published: November 2018

It was described the test of sewage sludge and organic fraction of municipal mixed solid waste thermal disintegration process. The waste activated sludge used during the tests was collected from the secondary settlement tank in a mechanical-biological wastewater treatment plant. The biowaste used in the studies was collected from an area of new buildings. It was noticed from means values of Soluble Chemical Oxygen Demand (SCOD) plot that both heating temperature and time, influence the amount of dissolved COD. The observations indicate that changes of SCOD can be described by an increasing, differentiable function of time and the rate of change of the soluble COD in the hydrolysates, in time is proportional to the difference of the maximum values of SCOD and its value in time, which leads to the relationship of the first-order ordinary differential equation. The process effectiveness depending on the temperature was described with the mathematical model including Van't Hoff-Arrhenius equation. Inspection of the data and some preliminary fits indicates, that for the description of changes in SCOD terms of time and temperature were adopted the form of nonlinear mixed model. Values of k20 indicator and Θ parameter depend on the substrate type. For waste activated sludge thermal disintegration, value of reaction speed indicator k20 was 0.028 h-1 (0,67 d-1), and value of temperature indicator equalled Θ = 1.024. For thermal disintegration of biological waste, value of reaction speed indicator k20 was 0.016 h-1 (0,38 d-1), and value of temperature indicator equalled Θ = 1.016.
Mathematical modelling of waste activated sludge thermal disintegration
Authors: Myszograj Sylwia , Wojciech Magdalena
Published: November 2018

Chemical Oxygen Demand (COD) solubilisation was used to evaluate the impact of thermal pretreatment on the transfer of sewage sludge from particulate to soluble phase. It was gathering the experimental data needed for building of empirical mathematical model describing the relation between applied temperature and time and rate of COD solubilisation and degradation. In view of repeated measurements, in order to describe the relationship between changes in the fraction of dissolved COD and the time and temperature, mixed models have been adopted where by fixed factor measurement conditions have been adopted: time and temperature, while the random factor changes the characteristics of waste activated sludge. Linear and logistic nonlinear mixed models were analyzed. The tests demonstrated that all variables are statistically significant in assessing their impact on the efficiency of liquefaction of sludge. On the basis of the estimated model, the temperature rise of 10°C increases degree of disintegration 1.7% above the average treatment time for 0.5h, by 2.6% for 1 hour, and by 3.9% for 2h. COD values decrease between 3 to 23% at temperatures in the range of 55 to 115°C. At higher temperatures COD was reduced in the range of 32 to 44%. Disintegration time did not have the significant impact on the degradation effect.
Postoptimization of the model of water supply for urban and industrial agglomeration
Authors: Wawrzosek Jacek , Ignaciuk Szymon
Published: November 2018

A case study of the tools used by an analyst of the economic aspects of the operation of the water supply network has been undertaken in this paper. All issues discussed here are formulated by using degenerated linear programming models (PL). Below, it is noted that the linear dependence of binding constraints (CO) distorts standard postoptimization procedures inPL. This observed fact makespostoptimization analysismostly unhelpful for an average analyst due to problems with the int erpretation of ambiguous sensitivity reports which are obtained from popular computer packages. In standard postoptimization methods, changes to single parameters of the right-hand vectorCOare analyzed or referred to parametric linear programming that unfortunately requires prior knowledge of mathematically and economically justified vectors of changes of right-hand sidesCO. Therefore, it is suggested that modifications are introduced to some of the postoptimization procedures in this work. For issues in the field of hydrology, the following were presented: interpretation and methods of generating justified vectors of changes of right-hand sides of limiting conditions. And so, the procedure of generating infinitely many solutions of the dual issue based on certain vectors orthogonal to the vector of right-hand sides of constraint conditions was demonstrated. Furthermore, the same orthogonal vectors were used to obtain nodal solutions of the dua0l model and the corresponding vectors of changes of the entire right-hand sides of the constraint conditions. Then, managerial interpretation was applied to this way of proceeding. The methods presented in the work serve to improve the functioning of the system of water supply.
Kernel density estimation and its application
Authors: Węglarczyk Stanisław
Published: November 2018

Kernel density estimation is a technique for estimation of probability density function that is a must-have enabling the user to better analyse the studied probability distribution than when using a traditional histogram. Unlike the histogram, the kernel technique produces smooth estimate of the pdf, uses all sample points' locations and more convincingly suggest multimodality. In its two-dimensional applications, kernel estimation is even better as the 2D histogram requires additionally to define the orientation of 2D bins. Two concepts play fundamental role in kernel estimation: kernel function shape and coefficient of smoothness, of which the latter is crucial to the method. Several real-life examples, both for univariate and bivariate applications, are shown.
Tribological properties of experimental hard alloys in conditions of friction on structural steel without lubricant
Authors: Fominoff Evgeniy V. , Shuchev Constantine G. , Khozyaev Igor A. , Tsarev Yuriy A. , Rykov Viktor B.
Published: November 2018

Tribological properties of the experimental grades of high entropy hard alloys with modified binding phase on cobalt, which are characterized by minimal value of absolute t.m.f. to carbide phase, were experimentally investigated. It was established experimentally that new grades obtain better friction characteristics in comparison with the base alloy grade VK8 because friction processes of these materials in contact with structural steels are characterized by lower friction forces and lower temperatures in the friction zones. The ‘third body’ which is thicker than for the base alloy grade VK8, obtains a positive gradient of mechanical properties in friction zone, has a shielding effect, reduces the rate of generation of adhesive joints (welding bridges), and, perhaps, performs the role of dry lubrication.
The active working shoot modeling profile of the centrifugal microturbine
Authors: Efimov Nikolai N. , Skubienko Sergei V. , Kopitsa Vadim V. , Kolodyazhny Igor Y. , Anisimov Evgeny A. , Ermakov Ivan I.
Published: November 2018

For the small distributed power, microturbines of electric 30-500 kW capacity are used: gas piston engines, gas and steam turbines, each of which has certain advantages and disadvantages. In the work, the active working blade profile is simulated for a single-stage, two-stream, centripetal microturbine, in order to determine the optimum profile design satisfying the reliability conditions and economy. The basis is a humidsteam microturbine of a horizontal electric version with a capacity of 30 kW. The initial data for software simulation were the microturbineactive stage characteristics, determined by the steam turbines calculation traditional methods.
Structural and kinematic analysis of a stirred tank planetary drive
Authors: Prikhodko Alexander A.
Published: November 2018

Stirred tanks are used in many industries to intensify various physical and chemical processes. Currently, one of the most promising areas of research is the creation of rotationally reciprocating stirred tanks (RRST), which realize high mixing efficiency due to the difference in the velocities of the stirred liquid. As the actuator of RRST, we proposed to use a planetary gear with elliptical gears. Due to the variable transmission ratio of elliptical gearwheels, the rotationally reciprocating motion of the output shaft is ensured with rotational motion of the input shaft. We conducted a structural analysis of the planetary gear by means of the structural mathematical model of mechanisms and machines. A kinematic model of planetary gear has been constructed and studied, resulting in velocity analogue function of the mechanism output shaft.
Projection of the hydraulic pressure drive with application of partial synthesis
Authors: Rybak Alexander T. , Pelipenko Alexey Yu. , Shishkarev Mikhail P. , Nevzorova Marina Yu.
Published: November 2018

In this article “Projection of a Hydraulic Pressure Drive with Application of Partial Synthesis” for the best comprehension and also receiving more complete picture, definitions of the term projection are considered, some fields of activity in which it is applied, namely technological, agricultural mechanical engineering etc are listed. An important part of cars, the drive is, the hydraulic actuator is most often applied – projection of which will be described in this article. First of all the existing technique projection of a hydraulic actuator is considered and its principle is described and shortcomings are designated. For carrying out a better designing process the new technique of projection of a hydraulic pressure drive which includes a stage of partial synthesis is offered. This stage allows explaining the theory of a volume rigidity which in turn allows to simplify calculations because it is possible to count several options of preliminary structures at the same time that will lead to receiving a hydraulic actuator with the best parameters, unlike the previous considered technique.
Substantiation of the parameters of vibration systems in the cab of the gantry crane at the workplace of crane operators
Authors: Kobzev Kirill O. , Shamshura Sergey A. , Chukarin Alexander N. , Buryanov Alexey I. , Kasyanov Valeriy E.
Published: November 2018

Reduction of vibration in the cabin can be achieved by increasing the area of vibration absorption by placing on the ceiling and floor vibro-absorbing facings. The process of absorption of vibration occurs due to the transition of the energy of oscillating particles to heat due to frictional losses in the pores of the material; therefore, for effective vibration absorption, the material must have a porous structure, the pores must be open from the side of the vibration and join together (unclosed pores) so as not to prevent the penetration of the vibration wave into the thickness of the material. As a vibration-absorbing cladding, we use a construction in the form of a layer of a homogeneous porous material of a certain thickness, reinforced directly on the surface of the fence.
Processing parameters influence on dynamics of vibratory drilling with adaptive control
Authors: Ivanov Ilya I. , Voronov Sergey A.
Published: November 2018

Chip segmentation is one of necessary conditions of ensuring the deep hole drilling quality when processing hard-to-machine metals. It may be achieved through making drill bit harmonic oscillations in axial direction. Possible way to maintain such vibrations is to replace the standard drilling head with special vibratory head which includes elastic element giving the instrument a possibility to move in axial direction. Self-excitation of drill regenerative oscillations is possible if elastic element stiffness and processing parameters are chosen properly. It is advisable to complement this way of excitation by control action which is determined in feedback circuit and sustains required vibration process characteristics in wide range of processing parameters. In present paper the adaptive control algorithm of vibratory drilling process dynamics is proposed. Control action on oscillation system is proportional to drill vibrational velocity, the feedback gain is determined in adaptation circuit basing on comparison of actual peakto- peak vibrational displacement and its target value. Simulation of closedloop nonlinear system «elastic system – machining process – control system» dynamics has been performed for different values of processing parameters for cases with or without control. The simulation revealed efficiency of suggested algorithm in wide range of processing parameters. Joined influence of processing parameters and target peak-to-peak displacement values on chip breakage conditions is studied. Recommendations for choice of processing parameters and control parameters values are developed. Influence of control action magnitude limit on control system possibilities to achieve control target is analyzed.
Investigation of stationary trajectories with associated milling by spur gears
Authors: Gubanova Alexandra A.
Published: November 2018

When milling in a steady state, unlike, for example, turning, there are periodic elastic deformation displacements of the tool relative to the workpiece along the machining path. Instead of an equilibrium point, we consider a certain closed trajectory of elastic deformations. This is the trajectory to which all the trajectories approach asymptotically, while forces and deformations that mutually affect each other through the mechanism of changing the area of the cut-off layer are redistributed. The article proposes a mathematical apparatus and algorithms for calculating the trajectory of establishing a stationary state. The case of milling with spur mills is considered. A mathematical description of the “basic” dynamic model of the associated milling by the side teeth of the end mills for the complete non-stationary nonlinear connection formed by the milling process is presented. It differs from known models by considering spatial oscillations, taking into account the dependence of forces on the cutting speeds, taking into account the rates of elastic deformation displacements, taking into account the retardation of forces with respect to deformation displacements, and also by nonlinear damping caused by forces acting on the trailing edge of the tool. In addition, periodic changes in the parameters and the formation of the surface at the previous contact of the tooth are taken into account.
Measuring system for liquid level determination based on linear electro-optical effect of liquid crystal
Authors: Denisova Olga
Published: November 2018

This article describes an updated system for measuring and controlling the level of liquid media. Well-known capacitance method for determining the liquid level is modernised. The new scheme proposes the use of electro-optical cell with a nematic liquid crystal. Homeotropically oriented liquid crystal is sandwiched between two plates, one of which is glass, and the other – crystal – cadmium sulfide CdS photoconductor. liquid crystal cell serves as an indicator. Its light transmittance depends on the applied voltage. Cell is designed so that the dependence of the phase delay of the voltage is linear. The article describes a mathematical model showing linear dependence, confirmed experimentally. Application of linear electrooptic effect observed in liquid crystals, allows to improve the accuracy and speed of measurement of liquid media, as the liquid crystal is an anisotropic medium more sensitive than solid crystals. The relaxation time of the orientation effects in liquid crystals is ~10-6 s. From the point of view of practical significance, this method will be of interest for application in the fuel and energy complex, in particular, oil and gas industry for the commercial accounting of petroleum products.
Adaptive drive of the technological machine with two working movements of the executive body
Authors: Lemeshko Mikhail A. , Molev Mikhail D. , Iliev Alexey G.
Published: November 2018

The article deals with the machines schemes, having an executive body making two movements and establishing a relationship between them. The ratio of the moving velocities, or the ratio of the two displacements of these movements, or the ratio of the applied powers to each of these movements, determines the indices of the working process, and often has an optimal value. A typical example of this type of machine is a drilling machine. The ratio of rotation speed and the feed rate determines both the specific power intensity of the cutting process , the intensity of the wear out and drilling capacity. The structural schemes of the drive of some other technological machines are considered. On the example of a device used for processing curved surfaces in metalworking, a process of automatically adjusting chip thickness with a hydraulic drive having an adaptive structure is described. The efficiency of self-regulation is shown by means of using relatively simple circuit solutions.
Review of robotic manipulators and identification of the main problems
Authors: Goryanina Ksenia I. , Lukyanov Aleksndr D. , Katin Oleg I.
Published: November 2018

One of the main elements of automation of industrial enterprises is the use of robotic systems consisting of mechanical manipulators and control systems. In recent years, the market of service robotics has been actively developing. The main part of the market of professional service robots in value terms is occupied by medical devices. Agriculture and logistics are also actively developing areas. The success of the automation systems implementation depends on the solution of complex scientific and technical problems, primarily in the following areas: machine vision; sensor networks; navigation systems. Thus, one of the fundamental problems, the solution of which largely depends on the success in creating the perfect adaptive and intelligent robots, is the use of such types of sensors of sensory information, which allow obtaining a sufficiently large amount of information about the problem environment in a short time. This is a problem of creating means of perception.
Analysis and solution of problems in the development of automatic color sorting systems
Authors: Katin Oleg I. , Goryanina Ksenia I. , Vernezi Miroslav A.
Published: November 2018

The development of automatic sorting systems is relevant and in demand in various industries. In particular, in the food industry, such systems are used to sort different fruits of plants by color. However, there are a number of difficulties associated with the development process. These include filtering the light flux and finding the optimal data processing. This article briefly reflects the steps that have been taken in finding the best way to illuminate the control area, and describes how to solve the problem of the influence of different types of lighting on the sensor readings. The method of processing data from the color sensor by the method of standards is also considered. The described solutions allow to achieve the required results in the development or optimization of automatic color sorting systems.
Mathematical modeling and parametric identification of dynamic properties of mechanical subsystems tool and workpiece in turning process
Authors: Tung Pham Dinh
Published: November 2018

Research and modeling of dynamic structures of the subsystems tool and the workpiece is given continued attention. This is due to the fact that the analysis of the stability of the cutting process and the self-oscillation is necessary, first of all, to have a model of the dynamics of interacting subsystems tool and workpiece through the cutting process. A similar problem is in the study of the machining accuracy, particularly in cases where the workpiece has significant deformation displacement varying along the trajectory of the tool relative to the workpiece. This paper considers the problem of mathematical modeling and identification of inertial, damping, and stiffness properties of the subsystems tool and workpiece in the dynamics exercises of the cutting process. The algorithms and the results of the identification of parameters in mathematical models of mechanical subsystems tool and workpiece for the case of turning are resulted.
Modification of the titanium implants surface with TiO2 coatings obtained by sol-gel method via dip-coating
Authors: Tarala Vitaly A. , Dolgalev Alexander A. , Kravtsov Alexander A. , Chikulina Irina S. , Bukhalov Boris V.
Published: November 2018

Within the framework of the study, TiO2 coatings were obtained by sol-gel method via dip-coating. For the films obtaining, manual drawing the substrate from the solution at a relatively high rate of 30 mm / min and automated drawing from the solution at low drawing rates (from 1 to 10 mm / min) were used. The morphology of coatings has been studied by scanning electron microscopy. The influence of the mode and the rate of drawing of the substrate from the solution on the films morphology was demonstrated. Analysis of the data showed, that the surface morphology of the coatings obtained at lower drawing rates by an automated method is much more homogeneous - the titanium dioxide films completely repeats the topography of the substrate surface, there are practically no fissures. Qualitative coatings of titanium dioxide, completely replicating the surface relief of the substrate, can be obtained by this method. Selection of the substrate drawing rate allows reducing the influence of the substrate topography and avoiding the appearance of crystallization centers, and as a consequence, the appearance of defects in the morphology of coatings, such as fissures or microparticles.
Contact problem on indentation of an elastic half-plane with functionally-graded coating in presence of tangential stresses on the surface
Authors: Volkov Sergei S. , Vasiliev Andrey S. , Sadyrin Evgeniy V.
Published: November 2018

Plane contact problem on indentation of an elastic half-plane with functionally graded coating by a parabolic punch is considered. The surface of the half-plane is additionally subjected to distributed tangential stresses in a certain region different from contact area. The contact area is assumed to be asymmetric with respect to the center of the punch. Tangential stresses are represented in the form of Fourier series. The problem is reduced to the solution of two dual integral equations over even and odd functions describing distribution of normal contact stresses. The bilateral asymptotic method is used to solve these equations. Approximated analytical solutions asymptotically exact for both the small and large values of relative coating thickness are constructed.
Investigation of the effect of some organic compounds on the formation of an antifriction film in a dioctyl sebacate medium
Authors: Kolesnikov Igor V. , Lebedinskii Konstantin S. , Boiko Mikhail V.
Published: November 2018

The influence of addition of malonic acid, diethylmalonate and acetylacetone to dioctylsebacate on the process of antifriction film formation is studied. It was found that the addition of small amounts of diethylmalonate and acetylacetone contributes to the acceleration of the tribosystem output to the regime. The addition of malonic acid slows down the process of forming an anti-friction film. The results suggest that the coordination iron compounds are involved in the process of antifriction film formation.
The efficiency is a single criterion for choosing the type of interaxle drive
Authors: Efimov Andrey V. , Kireev Sergey O. , Korchagina Marina V.
Published: November 2018

The efficiency is proposed as a single criterion for choosing the type of interaxle drive. Dependence of efficiency on road conditions is shown. On the basis of the proposed approach, the opportunity to select the type of interaxle drive by comparing the quantitative indices, while analyzing the entire range of road conditions, was demonstrated.
Optimization of actuating elements of transport control systems with magnetic levitation based on the solution of inverse problems
Authors: Balaban Anna , Bakhvalov Yuri , Grechikhin Valery
Published: November 2018

The designing of optimal energy-saving actuating elements for transport control systems with magnetic levitation (electromagnets with current windings and permanent magnets) is reduced to solving the following inverse problem. It is necessary to determine the dimensions and magnetomotive force of the actuating element, providing a given levitation force, magnetic induction in ferromagnets and a minimum mass of the actuating element. The solution of the direct problem (determination of the force of levitation and magnetic induction) is carried out by the finite element method. In the problem, the objective function is the mass of the actuating element and the restrictions are superimposed on the force and magnetic induction. Solving this optimization problem by the Lagrange method leads to inefficient algorithm. The article describes the proposed optimization method based on the transformation of constraints into objective functions, that is, the reduction of the problem to the multicriteria problem with consistent minimization of objective functions with a limited number of required parameters. A number of criteria are minimized analytically. The application of the complex criterion is considered. To reduce the time of solving the problem, the hierarchy of models is used: chain and field model. The proposed optimization method allows reducing the time of solving the problem by about two times. The cost of electricity due to the use of permanent magnets is reduced by four times. An example of optimization of the design of the actuating element of transport control system with magnetic levitation is considered.
Features of control of characteristics of radio engineering devices in the multi-wave mode of operation
Authors: Pichugin Vladimir N.
Published: November 2018

In multi-wave elements of radio devices at frequencies, 1,2,..., 10 times the operating frequency, conditions arise for the propagation of several types of waves. This leads to the dependence of the characteristics of electronic devices and, consequently, the parameters of frequency selectivity on the spatial structure (spatial spectrum, mode composition) of the electromagnetic signal at the input of the element under study. The presence of such” spatial selectivity” requires taking into account the features of the multi-wave mode in solving various problems of electromagnetic compatibility. The article is devoted to the actual problemthe development of new methods of experimental research and control of the characteristics of electromagnetic waves of radio devices operating in multi-wave mode. The solution of the problem of studying the impact of a plane electromagnetic wave on the emitters of the radio-thnical system is carried out. The analytical calculation of the electrodynamics effects in the multi-wave mode is carried out.
Dynamics of transformation of ultrasonic vibrations in twisted waveguides
Authors: Kudryshev Sergey B. , Minakov Valentin S. , Zakaluyzhnyy Alexey A. , Peglivanyan Vladimir A.
Published: November 2018

The effective use of ultrasound energy in various technological processes largely depends on the type of ultrasonic vibrations. Wide application in practice has found longitudinal ultrasonic fluctuations in connection with simplicity of realization, and also presence of the developed theoretical and settlement base. The longitudinal-torsional ultrasonic oscillations, the realization of which practically does not differ from the realization of longitudinal oscillations, and the efficiency and technological flexibility are much higher than for longitudinal or torsional ultrasonic oscillations, practically no applications have been found. This is due to several circumstances and, above all, from the theoretical basis for the transformation of this type of oscillation, since the theory of compressedtwisted rods was developed mainly in connection with the problem of longitudinal stability. The article deals with the case of transformation of longitudinal ultrasonic oscillations into complex ones by attaching to the last stage of the concentrator of the longitudinal acoustic system of the twisted waveguide.