bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Virtual Landscape Design Based on VR
Authors: Yang Yin
Published: February 2021

In recent years, with the rapid development of China’s urban landscape construction, people’s aesthetic requirements for high-quality landscape art image are constantly improving. However, the so-called “high-quality” and “diversified” landscape construction process is aimless and unrestrained, which aggravates the confusion of landscape visual organization form, and makes the original harmonious and complete landscape form present fragmentary and heterogeneous landscape visual characteristics. In view of these problems, this paper puts forward the visualization research of VR virtual technology in landscape design under big data analysis. In this paper, according to the current situation of visualization in landscape design in China, 220 landscape design workers and landscape customer groups in China were selected as the survey objects, and the satisfaction of VR virtual technology was more than 85%, which played a role in promoting the visualization of landscape design. Through the comparative analysis of standardization, intelligence and visualization between traditional landscape design and modern landscape design, it is concluded that each index of modern landscape design is superior to traditional landscape design. Visualization research in landscape design provides technical support for VR virtual technology under data analysis.
Optimized Allocation of Tennis Teaching Resources Based on Big Data
Authors: Cheng Peng , Ming Dayang , Man Xiaoni , Dai Donghui
Published: February 2021

In recent years, tennis has become a popular sport in China, whether in competitive sports or in the daily fitness of ordinary people is widely welcomed. However, due to the late development of tennis in China, the corresponding tennis teaching resources are relatively scarce, and there are problems such as unbalanced allocation. In view of this situation, this paper puts forward the research on the optimal allocation of tennis teaching resources based on big data. This paper makes an in-depth investigation on the current situation of Tennis Teaching under the background of big data, and analyzes various reasons for the backward allocation of tennis teaching resources. In view of these shortcomings, in order to improve the quality of tennis teaching in China, this paper combines the core concept of tennis teaching and big data technology, puts forward measures to strengthen the optimal allocation of tennis teaching resources, and creatively constructs a new basic principle of tennis teaching based on the background of big data. This paper investigates the current situation of tennis teaching development in 30 colleges and universities in China. Through the analysis results, this paper believes that using big data technology to optimize the allocation of tennis teaching resources can effectively improve the imbalance of existing resources and low learning efficiency.
An Experimental Study on Cultivation Model of Interdisciplinary Innovative and Entrepreneurial Talents in Internet Sports Industry
Authors: Liu Feiping
Published: February 2021

Interdisciplinary innovative and entrepreneurial talents can meet the needs of “Internet + sports” Industry development and better serve the local digital economy. Competence-based innovation and entrepreneurship education is a practical and effective teaching model for the artisan cultivation with innovative and entrepreneurial qualities. This article aims to study the craftsmanship talent training model and implement effect of information management and information system specialty. This article analyzes the basic connotation, features, advantages and implement process of craftsmanship talent education is applied innovative and entrepreneurial talents training model. The interdisciplinary undergraduate programs, typified by information management and information systems, have their unique characteristics in promoting innovation and entrepreneurship education. This article proposes a way to build a new model of “artisan” talents training in information management and information system majors to change the traditional Teaching mode to improve teaching quality and enhance students’ ingenuity and awareness. Experimental data show that the innovative and entrepreneurial craftsman-type talent training mode are conducive to the cultivation of talents and the storage of innovative and entrepreneurial talents, and can effectively increase the rate of success, the craftsman-type talent training model and information management system have increased the talent reserve of universities by about 23%, and shortened the talent training cycle by about 15%, which has promoted the development of innovation and entrepreneurship education in China.
PEGylation of graphene oxide nanosheets modulate cancer cell motility and proliferative ability
Authors: Gospodinova Z , Kamenska T , Gencheva G , Georgieva M , Krasteva N
Published: February 2021

Recently, graphene oxide (GO) has been increasingly investigated for its biomedical and biological applications, including cancer research. The interest is set on GO chemical modifications and their implications in the development of therapeutic approaches for various diseases. Recent data have demonstrated that PEGylation of nanoparticles (NPs) improves NPs solubility and stability in physiological solutions and alters their reactivity toward cancer cells. In this work, we have evaluated the effect of PEGylated GO nanosheets on the migratory and proliferation ability of A375 melanoma cells, used as a cancer cell model and have compared it to normal kidney MDCK cells. Both types of GOs, pristine and PEGylated, demonstrated an inhibitory effect on the cancer cells proliferation and mobility while on normal MDCK cells the effect of GO was significantly weaker at 48 hours of exposure suggesting that cancer A375 cells were more sensitive to GO and GO-PEG treatment. In general, PEGylation mitigates the inhibitory effect of GO on the growth and migratory ability of melanoma cells. Our results prove that the effects of both GOs NPs on cancer cells proliferation and mobility are dose-, NPs- and cell-type-dependent, hence providing a rationale for future design and use of graphene-based nanomaterials for cancer research.
Thermal variations of refractive and dispersive parameters of optical polymers
Authors: Kasarova S N , Sultanova N G
Published: February 2021

Temperature dependence of refractive and dispersive parameters of principal and some trade-marks of optical polymers has been studied. Refractive indices have been measured at several spectral lines in visible range at different temperatures between 0 and 50 °C. Thermo-optic coefficients have been determined and compared. We used the single-oscillator model of Wemple and DiDomenico to calculate oscillator energy and dispersion energy. These two quantities are related to the structure, charge distribution and chemical bonding of the material. Correlation to the dispersion properties of polymers is established. Variations of the two oscillator parameters with temperature are studied.
Investigation of polyelectrolyte multilayers deposited on corona charged composite polylactic acid / poly(ε-caprolactone) substrates
Authors: Bodurov I , Marudova M , Viraneva A , Yovcheva T , Grigorov A
Published: February 2021

In the present study chitosan and casein polyelectrolyte multilayers (PEMs) deposited on composite polylactic acid (PDLA) / poly(ε-caprolactone) (PEC) substrates were investigated. The substrate’s morphology was investigated using polarized light microscopy and their degree of crystallization was studied by the application of differential scanning calorimetry. The substrates obtained were charged in a corona discharge system, consisting of a corona electrode (needle), a grounded plate electrode, and a metal grid placed between them. Positive or negative 5 kV voltage was applied to the corona electrode. 1 kV voltage of the same polarity as that of the corona electrode was applied to the grid. The dependences of the normalized surface potentials on the storage times of positively and negatively charged substrates were studied. Layer-by-layer (LbL) technique was used for multilayer deposition on the substrates. PEMs with different number of layers (4 or 8) were obtained. A model drug Benzydamine hydrochloride was loaded in the casein layers in order to evaluate the effect of the kind of substrate on the drug immobilization and release. A study of the drug release kinetics in saline buffer was carried out and the amount of the released drug was calculated spectrophotometrically. It was shown that the experimental results fit to the Peppas model with a very good level of correlation and the model parameters differ depending on the used substrate.
Curcumin loaded casein submicron-sized gels as drug delivery systems
Authors: Milenkova S , Manolov I , Pilicheva B , Nikolova M , Marudova M
Published: February 2021

Hydrogels from natural polyelectrolytes possess many important features such as low toxicity, biocompatibility, biodegradability and hydrophilicity. These properties make them very suitable for applications such as immobilization and controlled release of drugs and other types of biologically active molecules. In the present study submicron-sized hydrogels made from casein by ionotropic gelation are investigated. For this purpose, two types of crosslinking agents are used at different pH conditions. In order to characterize these submicron gels, their sizes, chemical structures and thermal stability are examined by dynamic light scattering (DLS), FT-IR and Differential Scanning calorimetry (DSC) respectively. To prove their immobilization ability, active compound, namely curcumin, is immobilized in the hydrogel’s structures. DPPH assay is conducted to establish the antioxidant properties of the curcumin before and after the immobilization. The loading efficiency of the nanostructures together with the curcumin release kinetics are evaluated and modelled mathematically.
Complex electrical impedance and dielectric spectroscopy of Na+-conducting PEO/PVP/NaIO4 solid polymer electrolyte with incorporated nano-sized Graphene Oxide
Authors: Vlakhov T E , Marinov Y G , Hadjichristov G B , Scaramuzza N
Published: February 2021

Being of significant interest as electrolytic materials for mini-mobile energy storage devices, we have studied solid-state polymer-based electrolytic systems – nanocomposites, in particular, NaIO4 salt-complexed poly(ethylene oxide) (PEO)/polyvinyl pyrrolidone (PVP) polymer blends doped with nano-sized Graphene Oxide (GO). The GO monolayer average size and thickness were 5 μm and 2 nm, respectively. In the PEO/PVP polymer blend, the PEO:PVP ratio was 70:30 weight percent (wt.%), the concentration of the salt sodium metaperiodate NaIO4 was 10 wt.%. The nano-sized GO was dispersed with concentration of 0.2; 0.4 and 0.6 wt.%. Thin films (150 μm) of GO/PEO/PVP/NaIO4 Na+ ion-conducting nanocomposites were produced by solution casting technique. They were studied by complex electrical impedance and dielectric spectroscopy in the frequency range 0.1 Hz – 1 MHz of the applied electric field. The room-temperature ion conductivity, the complex dielectric function, dielectric loss and AC conductivity of GO/PEO/PVP/NaIO4 at various concentration of GO were obtained, and the effect from the GO nanofillers was estimated.
Single-photon generation of entangled triplet state in an atomic spin dimer
Authors: Varbev S , Boradjiev I , Chamati H
Published: February 2021

We show that the entanglement between two atomic spins, coupled via XY interaction, can be achieved with the aid of a single photon in a controllable manner. Assuming a constant spin-photon coupling, two distinct cases are considered — excitation with a constant and with a linear time-dependent photon frequency. We demonstrate that these problems reduce to the study of the well known Jaynes-Cummings and Jaynes-Cummings – Landau-Zener models, respectively, where the two-level system is formed by the zero-momentum mode states of the dimer. Owing to the exact solubility of both models, by tuning the relevant parameters, one can design and coherently control the dynamics of the excitation process. For instance, one can adiabatically switch from an atomic spin system initialized in a state with both spins down to the maximally entangled triplet state.
Infrared Optical Constants of Chromium Nano-films
Authors: Udachan S L , Ayachit N H , Udachan L A , Siddanna S , Kolkundi S S , Ramya S
Published: February 2021

In the present work, nanofilms of chromium have been prepared by thermal evaporation in vacuum on to ultrasonically cleaned glass substrates held at room temperature (22 °C). Films have been characterized by using X-ray diffraction (XRD) spectra, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Infra-Red (IR) spectra were used to examine the morphology and nano-structures to find out the cause. The transmission measurements were made on chromium films in the thickness range (6 – 60) nm for the incident photon energy of wavelength range, (2.5 - 4.5) μm. The optical transmittances of films have been found to decrease with increase in the film thickness in the entire IR spectral region of incident photon energy. In this case the optical constants like refractive index (n), absorption coefficient (a), extinction coefficient (k), real part (ε′) and imaginary part (ε″) of relative permittivity are obtained from IR spectrum.
Magnetic field effect in piezoelectric resonators with HTS electrodes
Authors: Nurgaliev T , Beshkova M
Published: February 2021

Microwave (MW) impedance of a square-shaped piezoelectric (PE) resonator containing an AlN film with tilted c – axis and high temperature superconducting (HTS) electrodes was modelled for the case of propagation of longitudinal and shear acoustic waves (AW) across the resonator thickness. External DC magnetic field B was assumed to be applied perpendicularly to the resonator surface. It was shown, that the magnetic field results in a decrease of the resonance frequency and an increase of the MW losses. The effect is due to a change of the MW impedance of HTS component under action of the magnetic field.
Solid particle radiator systems for heat rejection in space
Authors: Zhao C , Huang Y , Wang J
Published: February 2021

The radiator for the heat rejected in space proposes a new technological solution which utilizes a stream of solid particle to radiate waste heat. This paper presents the concept of Solid particle radiator (SPR) and highlights the distinctive characteristics of SPR and the Liquid droplet radiator (LDR). The design model of the solid particle radiator system was established and evaluated from the view point of reducing the rate of mass per unit power, avoiding the contamination due to the loss via evaporation and enhancing the efficiency of heat transfer. And the radiating temperature of this system could range to a large extent in the case of without considering evaporation loss. The mass model of system was presented here, and the evaluation parameters were used to analyze the performance of SPR in the different conditions. When compared with the performance of the liquid droplet radiator under the same condition of different mediums and Heat Pipe radiator, the SPR manifests the differences in the variations of thermal load, mission time and other design parameters of the system. Finally, this radiator exhibits the significant potential of substituting for the conventional radiator and the LDR in space according to the calculation results. Thus, the Solid particle radiator could be employed for a wide range of heat rejection applications in space.
The behavior to cavitation erosion of CuSn12-C bronze structures, as obtained by in-depth heat treatments
Authors: Lazar I , Bordeasu I , Mitelea I , Pirvulescu L D , Salcianu C L , Popoviciu M O
Published: February 2021

CuSn bronze alloys are some of the most used in the casting of freshwater ship propellers. Through in-depth heat treatments, the microstructure and hardness are substantially altered when compared with the initial state of the material after casting. The work highlights the change in the behavior and resistance to the vibrating cavitation erosion of the CuSn12-C bronze microstructures, after being subject to two in-depth heat treatments (hardening at 700ºC, followed by cooling in water, and two hardening treatments at 700ºC, with cooling in water, followed by tempering at 500ºC and 250ºC, with cooling in air). The experimental tests are performed using the vibrating standard piezoelectric crystal assembly, available in the Cavitation Research Laboratory at the Polytechnic University from Timisoara.
Elementary chemical analysis of different clay types
Authors: Aluvihara Suresh , Kalpage C S , Lemle K L
Published: February 2021

Clay is a useful raw material for most of industrial manufacturing processes because of the unique physico-chemical properties and chemical compositions of such clays. The analysis of chemical compositions of some clay is an important strategy that related with the usages of such clay for various industrial purposes. In the existing research there were expected to test and analyze the chemical compositions of three different clay types that available in various locations in Sri Lanka using the X-ray fluorescence (XRF) technique. The clay samples were collected carefully from the available locations and stored well. The clay samples were labeled as anthill clay, brick clay and roof tile clay based on the applications and origins of such clays. A sufficient portion from each clay sample was selected and those samples were oven dried for 24hours under the temperature 110°C and sent for the X-ray fluorescence (XRF) analysis. As the results for the investigations, there were observed the elements of Fe, Ti, Ba and K in the amounts of 82.08%, 4.84%, 0.79% and 12.28% from anthill clay, Fe, Ti, Ca and Ba in the percentages of 84.38%, 5.92%, 7.56% and 2.14% in brick clay and Fe, Ti, Ba, Zr and K in the percentages of 75.72%, 2.95%, 5.30%, 3.36% and 12.67% from roof tile clay.
Fundamental physico-chemical and mechanical analysis of different clay types
Authors: Aluvihara Suresh , Kalpage C S , Lemle L D
Published: February 2021

Clay plays an important role in the most of industries that related with water treatment and food stowage industries. The adequate physic-chemical properties are the most recognized factor for the wide range of applications. The investigation of the fundamental physic-chemical and some mechanical properties of such clay is an insistent task before the selection of some material for some specific role. The analysis of the fundamental physic-chemical and grain size analysis of grain sizes of three different types of selected clays were the aims and objectives of the existing research. Clay samples were collected from three different locations in Sri Lanka and they were stored well. The clay samples were named as anthill clay, brick clay and roof tile clay. Some potion from each clay sample was separated and such separated clay samples were oven dried for 24 hours under the temperature 110°C. Each of dried clay sample was separated again and the separated portions were prepared for the test of moisture content, dry sieve analysis and wet sieve analysis. As the major results of the experiment, especially there were obtained 14.49%, 21.45% and 25.97% moisture contents with respect to anthill, brick and roof tile clays, well-graded particle arrangement in roof tile clay, gap graded particle arrangement in anthill clay and uniformly graded particle arrangement in brick clays. In addition, according to the obtained results there were seen the finer particle weight percentages as 59.90%, 37.36% and 72.38% with respect to anthill clay, brick clay and roof tile clay.
Spatial-factorial analysis of background status of the Danube River basin state on the northeastern slops of the Ukrainian Carpathians
Authors: Kravchynskyi R L , Korchemlyuk M V , Khilchevskyi V K , Arkhypova L M , Mykhailiuk J D , Mykhailiuk I R
Published: February 2021

The study solved the problem of analyzing the background spatial-factorial patterns of distribution of quantitative and qualitative indicators of groundwater sources and surface waters within the upper part of the Prut River that belongs to the Danube River basin. The studies have been conducted within the Carpathian National Nature Park, located on the northeastern slopes of the Ukrainian Carpathians. The basic regularities and peculiarities of the distribution of springs in the researched territory have been studied by means of factor analysis of the set of estimation parameters and the relationships between them. Patterns of changes in the concentrations of the natural components of the qualitative composition of the hydro-ecosystem have been found, depending on the altitude of the terrain. Similar data has been obtained in the analysis of the relationship between the average geometric components of the chemical composition of natural waters and the length of the river. Trend lines and equations have been obtained, which can be used to determine the background normative values of natural water components along the length of the stream and the altitude of the basin for individual seasons and phases of water. In this paper, for the first time, the functional natural pattern of hydro-ecosystems of the upper part of the Danube basin within the northeastern slopes of the Ukrainian Carpathians is shown to increase its qualitative potential with increasing absolute altitude above sea level for nature conservation territory.
A method to detect cracks in the beams with imperfect boundary conditions
Authors: Lupu D , Gillich G R , Nedelcu D , Gillich N , Manescu T
Published: February 2021

Non-destructive testing of structures involving vibration-based damage detection methods implies knowing the beam’s boundary conditions. For perfect boundary conditions, numerous damage detection methods are developed and ensure more or less accurate estimation of the crack type, position, and severity. On the contrary, for imperfect boundary conditions, which are the real ones, there are only a few dedicated works. This paper presents a methodology that allows the identification of the weak clamping and the crack if both exist. The weak clamping is modelled as a defect that produces an identical relative frequency shift (RFS) for all vibration modes. Therefore, to find the two defects namely the real crack and defect simulating the weakly clamped end, we apply the principle of superposition. The method is implemented as an application written in the Python programming language. Tests show that defects are successfully identified even if there are uncertainties about the fixing of the beam.
Mining terrain curvatures approximation using the polynomials and a subsidence trough profile fragmentation
Authors: Orwat J
Published: February 2021

In an article a method of average course obtaining of measured mining terrain curvatures has been presented. Terrain curvatures values are very important for building objects located on mining areas and which have a considerable length or/and a great cubature. Curvatures observed graph has an irregular course and that’s why there is a need of their average course determination in order to obtain the most probable value. Measured curvatures approximation by use of the polynomial various orders has been done. Additionally, a whole profile of subsidence trough into the parts has been divided. Subsidence trough fragmentation allowed for a better fit of the curvatures average values to the observed values. A right polynomial order and a trough segments proper number taking into account value of variability coefficient of curvatures random dispersion have been chosen. Geodesic surveys, based on which a graph of measured curvatures has been obtained, in the Upper Silesian Coal Basin (Poland) have been done. There was conducted a mining exploitation of hard coal deposits by use of the longwall system with a roof rocks cave-in.
Investigation of the influence of the cutter-tool rake angle on the accuracy of the conical helix in the tapered thread machining
Authors: Onysko O , Panchuk V , Kopei V , Havryliv Y , Schuliar I
Published: February 2021

Tapered thread joints used in drill pipes largely determine the productivity of drilling processes and their environmental reliability. The quality of these joints depends on the values of the rake angle of the cutting insert of turning cutters used for making tapered threads. Modern manufacturers, because of the absents of algorithms for calculating the precision of the execution of the tapered thread spiral, depending on the size of the rake angle use the cutters only with a zero value of this angle. This greatly limits the possibility of producing drill pipes from high-strength materials, which is absolutely necessary in the modern drilling methods: obliquely directional and horizontal. The kinematic analysis presented in the article proves the difference between the theoretically specified spiral and their realized in the course of machine processing with cut tools with non-zero values of the rake angle. The deviation of the thread incline angle that is realized during turning is not regulated by standard requirement, as it is variable. The precision of the pitch of the tool-joint tapered thread is regulated by standard and must be ensured by the kinematics of the lathe. However, when screwing, the spiral screw lines of the pin and the box thread may not match, provided that they are made with using of tools with different values of the rake angle. Thus, it is lead to exceed the tolerances by one pitch. The algorithm allows to calculate the axial deviations of the screw line, depending on the value of the rake angle of the cutter for any of the points of the thread profile. It brings the fit of the cutters with a rake angle up to 5 ° to ensure the accuracy of the executed helices in the tapered thread machining.
The requirements for the design and construction of a gas cylinders aimed for transportation of a compressed and liquefied gases
Authors: Golubović-Bugarski V , Todić M , Petković S , Globočki-Lakić G
Published: February 2021

In this paper a typical requirements for the design and construction, workmanship and tests of a gas cylinders of water capacity between 150 l and 3000 l are described. This type of gas cylinder presents a refillable seamless steel tube aimed for transportation of compressed and liquefied gases exposed to extreme world-wide ambient temperatures. These tubes can be used alone or in batteries to equip trailers or multiple element gas containers (ISO modules or skids). When it comes about design requirements, the main focus is on the cylindrical shell thickness, which is calculated using the Lamé-von Mises formula. For some applications such as tubes assembled in batteries to equip trailers or skids (ISO modules) or MEGCs for the transportation and distribution of gases, it is important to calculate stresses associated with mounting the tube (bending stresses, torsional stresses, dynamic loadings etc.). Special attention must be paid to design of tube ends, which should be approximately hemispherical. To permit internal visual inspection of the tube, an adequate opening must be provided at the neck ends. The tubes are manufactured from seamless steel tubing, typically hot rolled, extended/extruded or forged. The ends of tube are hot formed using either forging or spinning methods. After manufacturing process, each tube must be inspected in terms of surface imperfections. Next, each tube must be ultrasonically examined for internal and external defects and laminar imperfections and to determine wall thickness. Batch tests for checking the quality of tubes includes mechanical testing, such as tensile and impact testing. Beside the batch tests, all tubes must be subjected to the following tests: a hydraulic proof pressure test or a volumetric expansion test, a hardness test, a visual inspection, a visual check of the stamp markings, a dimensional inspection and an ultrasonic non-destructive testing (NDT). At the end of this paper, the most commonly found manufacturing imperfections are pointed out.
Temperature-frequency converter made with astable multivibrator and thermistor
Authors: Popa I , Popa G N , Diniş C M , Iagăr A
Published: February 2021

The temperature can be measured electrically by several methods: with thermoresistive transducers, with thermocouple transducers, with thermistors, with the pn junctions of semiconductor devices, etc. Thermistors are electrical resistors made of metal oxides with semiconductor properties, which are small in size, have very small time constants and can measure temperatures locally, without disturbing the temperature range in the measured area. In order to conveniently transmit the temperature information (without errors) at a distance, the paper uses an astable multivibrator circuit RC type, in which the resistor is replaced with a thermistor with negative characteristic, whose resistance changes depending on the temperature in a range allowed by this type of oscillator. After several experiments, it was established that for a certain value of a capacitor, using a thermistor with a negative characteristic, the frequency of the oscillator (rectangular signal) changes quasi-linearly (in the range of tens of kHz). The measured temperature (tens of 0C) corresponds to the environment in which the thermistor is mounted. It was possible to determine the value of the astable multivibrator circuit capacity for which the temperature and frequency ranges in which the converter is considered to operate quasi-linearly were established. The signal obtained from the output of the astable multivibrator circuit is transmitted remotely to a digital port of a microcontroller development board with an LCD shield that displays the measured temperature. Also, it is present the flow chart of program implemented in microcontroller.
Elastic couplings design with bolts using iPart and iAssembly concepts
Authors: Zs Miklos I , Miklos C C , Alic C I
Published: February 2021

This paper presents the possibilities for designing an elastic coupling with bolts, using the concepts iPart and iAssembly. Concepts iPart and iAssembly are in the category of tools to increase the productivity of computer-aided design in Autodesk Inventor. When designing the elastic coupling with bolts, these tools are very useful and productive, because the components of the coupling and the assembly have the same geometric shape with different types of dimensions. Basically, iPart and iAssembly tools allow creation of libraries for components (flanges, bolts, etc.) and elastic coupling, geometrically modeled once, which extract their dimensions from pre-created value tables, depending on coupling size determined based on the transmitted torque. In this respect, it is necessary that the components and the assembly to be modeled parametrically, i.e. all the dimensional constraints applied to be defined by a clear parameter
Predicting the dynamics of the maximum and optimal profits of innovative enterprises
Authors: Ilyina E A , Saraev L A
Published: February 2021

This article proposes new economic and mathematical models of the dynamics of the development of industrial enterprises that introduce innovative technologies. The level of attraction of innovative technologies by the enterprise is set by dimensionless coefficients of innovations, which depend on time and affect the increase in output and decrease in costs. The influence of not only production costs, but also transaction costs on the size of the enterprise’s profit was investigated, the sources of which are the forced costs of searching and processing economic information, financing negotiation procedures, developing and concluding contracts with partners, organizing the protection of property rights, paying for the opportunistic behavior of employees and enterprise managers, etc. It is found, that transaction costs force to maximize not only the profit function of the enterprise, but also the target transaction utility function, which takes into account the redistribution of profits in the interests of the enterprise management and for the implementation of socially oriented programs. The size of the part of the profit spent in the interests of the enterprise management and for the implementation of socially oriented programs is set by dimensionless redistribution coefficients. It is shown, that in the presence of transaction costs, the enterprise, instead of the maximum value of profit, achieves a lower optimal value of profit.
Making decisions on issuing sub-federal bonds in Russia: key factors modeling
Authors: Yakunina A , Mitrofanov A , Ermakova E , Yakunin S , Korobov E , Semernina Y
Published: February 2021

Recently, Russian regions have been more active in using sub-federal bonds to finance regional debt. However, the Russian sub-federal bonds market’s liquidity is still low while regional authorities often use commercial bank loans to finance the regional budget deficits. The purpose of this study is to identify the key factors influencing the regional authorities’ decisions to issue sub-federal bonds. The impacts of the following factors were assessed: the regional budget deficit volume, the Central Bank key rate, the budget loan proportion of the regional debt, the regional debt burden, average per capita cash income in the region, the employed in the region. We used monthly data for 85 regions (constituent entities of the Russian Federation) for the period 2015–2019.

Various regression models for panel data have been developed: those predicting probabilities of a non-zero value of regional bond volume, the volume itself, and combined generalized linear mixed hurdle model with a negative binomial distribution (estimated with glmmTMB contributed package of R). The latter showed non-significant dependence of regional bond volume on region budget surplus, prioritizing unobserved region-specific random factors.
Mathematical modeling of circular sandwich plate interaction with viscous liquid layer for predicting its hydroelastic response
Authors: Kondratov D V , Mogilevich L I , Popov V S , Popova E V , Chernenko A V
Published: February 2021

The paper proposes a mathematical model for predicting the hydroelastic response of a mechanical system consisting of a circular sandwich plate forming the bottom wall of a narrow channel filled with a pulsating viscous liquid. The pressure pulsation in the liquid layer is caused by upper vibrating channel wall represented by a rigid disk. We needed to formulate and solve the hydroelasticity problem for developing the mathematical model. The hydroelasticity problem consisted of the Navier-Stokes equations, the continuity equation, the circular sandwich plate dynamic equations, and the corresponding boundary conditions. The viscous liquid layer movement was assumed as a creeping one. We studied the stationary axisymmetric hydroelastic oscillations problem under harmonic pulsation of liquid pressure, i.e. harmonic vibrations of the upper channel wall. Using the perturbation method, we obtained the system of two integro-differential equations for studying the radial and flexural vibrations of the sandwich plate. Hydroelastic oscillations of the main mode were considered as a special case. The program for calculating the hydroelastic response of circular sandwich plate in various frequency ranges was developed. As an example, we made calculations of the circular sandwich plate amplitude-frequency response. The developed model can be applied in monitoring and decision-making systems for complex mechanical objects.
Mathematical models of the development of industrial enterprises, with the effect of lagging internal and external investments
Authors: Saraev A L , Saraev L A
Published: February 2021

The article proposes new models of the dynamic development of enterprises that restore their production through internal and external delayed investments. Differential balance equations for such enterprises are established, which describe changes in factors of production and output. Proportional, progressive and digressive depreciation deductions are considered and their interaction with internal and external investments is investigated. The conditions of the limiting state of work of enterprises are formulated and the corresponding values of the factors of production are calculated. Various options for the development of enterprises, including their stable operation, temporary suspension of their activities for the period of technical re-equipment, and temporary partial curtailment of their production, have been investigated. The regularities of the influence of the volumes of depreciation deductions, internal and external investments on the dynamics of enterprise development are revealed. Numerical analysis of the developed models showed good agreement with the known statistical data on the work of industrial enterprises.
Assessment of structural changes in the spatial innovative development of Russian regions
Authors: Firsova A A , Tsypin A P
Published: February 2021

The study of the effectiveness of spatial innovation development is a highly topical issue today due to the increased impact of innovation on economic growth. In order to assess the structural dynamics of regional innovative development, an analysis of the innovation indicators for Russian regions in 2010–2018 was carried out. Cluster analysis and the correlation-regression method were used to assess the structural changes in the innovative development of Russian regions. The analysis demonstrates an increased number of entities in the innovative leading region cluster by 2018, which can be considered as a positive result of innovation policy and the growth in indicators of regional innovative development. The research results can be used to develop regional innovative strategies and decision making for the further development of innovative activities.
Thermal deformation and polymorphic transitions of 1,1-diamino-2,2-dinitroethylene in the temperature range from 145 to 475 K
Authors: Stankevich A V , Taibinov N P , Kostitsyn O V , Garmashev A Yu
Published: February 2021

Under atmospheric pressure conditions, direct polymorphic transitions α to β, β to γ and reverse γ to α were studied, as well as certain phase equilibrium points for 1,1-diamino-2,2-dinitroethylene (DADNE) were determined in the temperature range from 145 to 475 K. The anisotropic characteristics of the thermal deformation of DADNE crystals are determined by powder thermal x-ray diffraction of an internal standard. The points of structural changes were recorded in increments of 20, 10, and 2 K. The calculations of x-ray powder diffraction data were carried out using full-profile analysis methods with the integrated cycle of molecular modeling of the structure of molecules integrated into the algorithm.
Molecular dynamics simulation of ion binding in aqueous solution of 18-crown-6 ether
Authors: Bakulin I K , Kondratyuk N D , Lankin A V , Norman G E
Published: February 2021

Crown ethers are unique compounds with exceptional ion binding properties. We investigate the 18-crown-6 ether molecule binding selectivity for a set of alkali ions (K+, Rb+, Cs+). We employ combination of umbrella sampling technique with the weighted histogram analysis method to derive free energies of ion–ether association. The obtained results are in a good agreement with experimental values available and represent the ion selectivity feature of the 18-crown-6 ether.
Detonation properties of explosive proppants based on slurry nitromethane plus ammonium perchlorate mixtures
Authors: Komissarov P V , Basakina S S , Lavrov V V , Sokolov G N
Published: February 2021

In this paper, the results of investigation on detonation properties of heterogeneous mixtures of ceramic proppants with slurry liquid explosives (LE) such as nitromethane (NM) plus ammonium perchlorate compositions are presented. The mixtures discussed are promised to be used for far field fracture stimulation of oil bearing formation subjected to hydraulic fracturing. Experimental results on detonation velocities of LE-proppant mixtures in long tubes up to 25 diameters versus internal diameters are presented. Results of experimental comparison of detonability of LE studied with pure NM in proppant matrix are also represented. The objective of the study was to assess detonability and detonation parameters of these mixtures at various initial conditions.
Investigation of plasma states formed under the interaction of high-power laser pulses with wire-shape Al–Cu target
Authors: Golovin D O , Alkhimova M A , Pikuz T A , Abe Y , Honoki Y , Lee S , Matsuo K , Koga K , Okamoto K , Shokita S , Arikawa Y , Faenov A Ya , Fujioka S , Pikuz S A , Skobelev I Yu , Nishimura H , Yogo A
Published: February 2021

Study of warm dense matter remains a very important task for understanding of many unique phenomena observing as in astrophysical research as in inertial fusion and fast ignition. In this work, we studied the parameters of plasma created by 1.7 ps laser pulses of relativistic intensity of 7 × 1018W/cm2in a specially designed Al–Cu wire-shape target, in comparison with a flat Cu and Al foil targets. We observed the strong emission of neutral or virtually neutral CuKαline from both Cu foil and Cu wire part of targets, which indicates the creation of a dense state exposed to the intense flow of hot electrons. Parameters of the plasma were evaluated by comparison of experimental spectra with the results of modeling by collisional-radiative kinetic code PrismSpec under the plasma zone approach. The using of Al foil in front of Cu wire part of target allowed avoiding the direct heating of Cu-wire and acquiring spectra of Cu K-shell emission evidently belonging to emission of warm dense matter (WDM) state. The upper estimate for the electron temperature in WDM region was found to be below 80 eV.
Intensification of heat transfer during spinodal decomposition of a superheated aqueous oligomer solution
Authors: Volosnikov D V , Povolotskiy I I , Igolnikov A A , Vasin M G , Son L D , Skripov P V
Published: February 2021

The heat conduction of an aqueous solution of polypropylene glycol in the region of stable and unstable states was studied by the method of pulse isothermal impact on a substance with a characteristic time of 100 ms. It has been shown that the short-term superheating of a homogeneous solution not only above the liquid-liquid equilibrium temperature (low critical solution temperature), but also above the diffusion spinodal is fundamentally possible. The negative character of the deviation of the heat conduction of a solution from the additive law calculated from the heat conduction of the pure components at a given temperature was revealed. The signs of manifestation of spinodal decomposition accompanied by a significant intensification of heat transfer were found.
Search for muon neutrinos from the gravitational wave event GW170817 at the Baksan Underground Scintillation Telescope
Authors: Boliev M M , Butkevich A V , Dzaparova I M , Kochkarov M M , Kurenya A N , Lidvansky A S , Novoseltsev Yu F , Novoseltseva R V , Petkov V B , Striganov P S , Yanin A F
Published: February 2021

Using data of the Baksan Underground Scintillation Telescope we have searched for muon neutrinos and antineutrinos with energies above 1 GeV coinciding with the gravitational wave (GW) event GW170817 that was recorded on August 17, 2017, by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo observatories. This is the first detection of the new type of events occurring as a result of a merger of two neutron stars in a binary system. A short gamma-ray burst (GRB) GRB170817A accompanying this event is evidence of particle acceleration in the source whose precise position was determined by detection of the subsequent optical signal. No neutrino signals were found with the Baksan Underground Scintillation Telescope in the interval ±500 s around the moment of the gravitational wave event GW170817, as well as during the next 14 days. The upper limits on integral fluxes of muon neutrino and antineutrino from the source are derived.
Impact of nuclear gluon distributions on leptoquark production by neutrinos
Authors: Alikhanov I
Published: February 2021

We investigate non-standard interactions of neutrinos with atomic nuclei through excitations of leptoquarks. A leptoquark term in the Lagrangian admits the possibility that neutrinos interact with gluons. The current lower limits on the leptoquark masses are of the order of 1 TeV depending on the leptoquark quantum numbers and couplings. Such heavy states can be produced in ultra-high energy cosmic neutrino scattering processes. The four-momentum transfer squared and the Bjorken variable simultaneously probed in these processes may reach values kinematically inaccessible at present collider experiments. We study the impact of the gluon density in a nucleus on the cross section for the neutrino-induced leptoquark production. We show that taking into account the nuclear parton distributions shifts the production threshold to significantly lower neutrino energies. As a particular case we consider the interaction with oxygen, which is abundant in water targets used in neutrino detection experiments.
Simulation of shock-body interactions using the Runge–Kutta discontinuous Galerkin method with adaptive mesh refinement implemented on graphic accelerators
Authors: Korneev B A , Zakirov A V , Levchenko V D
Published: February 2021

In this paper, a numerical scheme for solving the equations of the dynamics of a compressible fluid, based on the Runge–Kutta discontinuous Galerkin (RKDG) method and an adaptively refined cubic mesh (AMR), is applied to the problems of shock interaction with solid and liquid obstacles. Features of effective implementation algorithm for the graphic processors (GPU) are described. Several well-known validation test problems are considered. Results of full detailed three-dimensional simulations of the shock with the gas or fluid bubble using the developed GPU–RKDG–AMR solver are presented.
Molecular dynamics analysis of incipient soot morphology
Authors: Goldshtein K D , Potapov D O , Shadymov V A , Orekhov N D
Published: February 2021

Understanding mechanism of the soot formation process is important for reduction of harmful emissions from combustion and also for synthesis of carbon nanostructures. However, at the moment, both the mechanisms of carbon cluster formation and its morphology are poorly understood. In this paper, we present the results of molecular dynamics simulation of the formation and growth of carbon clusters formed at high temperatures from polyaromatic hydrocarbons.
Increasing the trapping lifetime of lithium-7 atoms in optical dipole trap
Authors: Saakyan S A , Sautenkov V A , Morozov N V , Bobrov A A , Zelener B B
Published: February 2021

We have developed far-off resonance single beam dipole trap for optically cooled lithium-7 atoms. In the present paper we discuss some preliminary results. In order to improve performance of the trap we optimized the trapping time and increased the atoms number. The lifetime was increased by improving the vacuum from ≈ 3 × 10−10 Torr to ≈ 10−11 Torr and preparing all the atoms in the selected atomic state (the lower ground state level). After vacuum improvement the single particle losses in the magneto-optical trap was reduced by 100 times and as the result the lifetime in the dipole trap reached 25 s.