bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possible studies of explosively driven non-ideal plasma using a proton microscope at the Facility for Antiprotons and Ion Research
Authors: Shilkin N S , Yuriev D S , Mintsev V B , Bogdanov A V , Kolesnikov D S , Skoblyakov A V , Kantsyrev A V , Golubev A A , Hoffmann D H H , Varentsov D V 
Published: July 2020

Abstract
The article describes possible experiments with explosively driven non-ideal plasma at the proton microscope at the Facility for Antiprotons and Ion Research. It is proposed to employ linear explosive tubes for plasma generation and to measure an areal density in shock-compressed plasma of argon and xenon. The proposed experiments will provide valuable information on influence of strong interparticle interactions on thermodynamic properties of strongly coupled plasma. The density measurement will help the researchers to understand the nature of wall and wire precursors arising in the shock tubes.
Explosive character of instability development for the free surface of a conducting liquid in an electric field
Authors: Zubarev N M , Zubareva O V 
Published: July 2020

Abstract
In this work, a perfectly conducting liquid with a free surface, placed in an external uniform electric field, is considered. For a symmetric spatially localized perturbation of the surface, which is directed upwards, it is proved that the part of the potential energy functional which is responsible for nonlinear wave interactions is negatively defined. It is important that this result is obtained without any restrictions on the amplitude of the boundary perturbations, i.e., it takes into account high-order nonlinearities. A general conclusion is that the nonlinearity plays a destabilizing role accelerating the linear instability development of the boundary and defining its explosive character.
Optimization of the radiotransparent constructions in a mode of extreme heat loads
Authors: Bocharov A N , Pahomov E P , Petrovskiy V P , Politiko A A , Semenenko V N , Chistyaev V A 
Published: July 2020

Abstract
An experimental method has been developed for optimizing the composition of multilayer radiotransparent structures operating under extreme thermal loads. To optimize the composition of the layers of the radiotransparent radome researchers for the following materials with structures of the glass filler are carried out: glass-fiber laminate (GFR-CM), reinforced quartz material of SiO2–SiO2 class (HTRC-CM), organosilicon rubber with a ground mica filler (TCT). The parameters of the heat loads that cause physicochemical transformations in radiotransparent materials and significantly affect the transmission and reflection coefficients of materials, as well as their complex permittivity, are determined. It is shown that the decrease in the transmission coefficient for the construction made of HTRC-CM material is up to 3–4 dB in the frequency range from 2 to 40 GHz, and for constructions made of GFR-CM+TCT is up to 25 dB, respectively. As a result, the radome made of ceramic matrix composite HTRC-CM has the best radiotransparency characteristics.
Two-stage pyrolytic conversion of raw and pretreated bagasse into synthesis gas
Authors: Faleeva Yu M , Krysanova K O , Krylova A Yu , Zaichenko V M 
Published: July 2020

Abstract
Sugarcane bagasse is an abundant waste formed after extraction of sugarcane juice in the sugar-manufacturing process. This large-tonnage waste creates an ecological problem in countries—sugar producers. The study considers bagasse gasification, which is a two-stage pyrolytic conversion into synthesis gas. Raw bagasse and bagasse biocoal obtained by torrefaction and hydrothermal carbonization were used as initial materials. Experimental data are discussed including composition and quantity of gaseous products formed in the process. The results indicated that the process allows obtaining 1.26 m3 of synthesis gas from 1 kg of raw material. Its higher calorific value is 11 MJ/m3.
Research of technologies of local fuel and energy resources using for distributed power generation
Authors: Larina O M , Sytchev G A , Zaichenko V M 
Published: July 2020

Abstract
Development of methods of energy self-sufficiency is a priority for present power generation sector advancing. For our country, it is of particular importance. Approximately 70% of the territory of the Russian Federation (with a population of about 20 million people) are located outside centralized energy supply systems. Capacity of existing centralized energy systems is not enough for many regions of the country. At the same time, in the existing economic conditions, distributed power generation turns out to be more advantageous from an economic point of view in relation to centralized power generation. The production of energy without imported organic fuels implies local fuel and energy resources using, such as peat, wood, agricultural, household and other types of waste. Energy utilization of various types of waste, which are also local fuel and energy resources, will reduce the negative impact on the natural balance of accumulated environmental damage.
Treatment of granulated organic manure based on bird droppings by hydrothermal carbonization and torrefaction methods
Authors: Krysanova K O , Faleeva Yu M , Krylova A Yu , Zaichenko V M 
Published: July 2020

Abstract
Hydrothermal carbonization (HTC) and torrefaction are modern low-temperature methods of converting different types of biomass into biocoil. In both processes temperature significantly affects the product distribution and character of solid product. The heating values of HTC biocoil was much higher than torrefacted biochar and 40% higher compared to the initial raw materials (15.68 MJ/kg for raw materials, 22.3 MJ/kg for HTC 210 °C). Biomass has increased carbon content. The maximun one has biochar obtained at 210 °C (55% higher compared to the initial raw materials). The energy densification ratio and energy yield was also higher in HTC process compared to torrefaction process. Hydrochar has less ash that biochar obtained by torrefaction due to washing part of inorganic into the liquid phase.
Interaction of metastable shock waves with perturbations
Authors: Konyukhov A V , Levashov P R , Likhachev A P 
Published: July 2020

Abstract
The shock wave metastable behavior in equilibrium media is detected in numerical experiments. This phenomenon is directly related to the ambiguous representation of a shock wave discontinuity when the shock belongs to the S-shaped fragment of the pressure-velocity Hugoniot. After interaction with weak perturbations the metastable shock wave recovers its original form and parameters (like stable shock). If the amplitude of the perturbations exceeds some critical value, the shock wave instability is developed. The instability is accompanied by formation of the transverse secondary waves switching local post-shock parameters between two Hugoniot segments separated from each other by the absolute instability region. The problem of the metastable shock wave interaction with local entropy perturbation passing through the shock front is studied in the framework of three-dimensional problem formulation. The shock wave transition to the limiting self-oscillating mode is described. Some features of this mode are completely determined by the shape of the Hugoniot and isentropes and does not depend on the shock wave structure. Namely, the shape of the shock front corrugations and flow structure evolution are analyzed. These features may be served as marker of the corresponding thermodynamic anomalies.
Vernier laser diagnostic system for velocity measurements at Angara-5-1 facility
Authors: Pirog V A , Tishchenko I Yu , Gubskiy K L , Kuznetsov A P , Laukhin Ya N , Frolov I N , Branitskii A V 
Published: July 2020

Abstract
The report presents a laser diagnostic system designed to analyze the behavior of a matter in extreme states and the propagation of shock waves. The research system consists of a pair of velocity interferometer systems for any reflector (VISAR), push pull and conventional VISARs, forming a vernier scheme. This configuration was designed for Angara-5-1 facility. Test experiments of metal plate acceleration using magnetic field were carried out. The velocities up to 6 km/s were obtained.
The role of instability mechanisms in gas flame acceleration
Authors: Elyanov A E , Golub V V , Mikushkin A Yu , Petukhov V A , Volodin V V 
Published: July 2020

Abstract
To study the role of individual mechanisms of the flame-front instability, a series of experiments was carried out on the propagation of a spherical flame. Transparent latex shells were filled with pre-prepared hydrogen–air mixture. In various series of experiments, the percentage of hydrogen was varied. The ignition of the flame was produced by a spark discharge with an energy of 1 mJ, a discharger located in the center of the shell. Experimentally, the scattering parameters of the spherical hydrogen–air flame acceleration was found with a constant mixture composition and combustion initiation energy. It was found that at the initial stage of propagation, both acceleration and deceleration of flame front occurs. The parameters of the flame front propagation experimentally obtained are supplemented by calculations carried out using analytical models.
Analysis of the effect of boron-containing compounds and combustion catalysts on paraffin combustion rate in an oxidizer flow
Authors: Shiplyuk A N , Lukashevich S V , Simagina V I , Netskina O V , Komova O V 
Published: July 2020

Abstract
The paper addresses to the experimental investigations of the combustion of test samples of solid fuels based on paraffin and boron-containing compounds and combustion catalysts in the gaseous oxygen subsonic flow. Tests were carried out at the atmospheric pressure and oxygen flow velocity from 27 to 31 m/s. The mass combustion rate of the samples increased by 28% when ammonia borane was added to paraffin, and by 16% when sodium borohydride with a bit of solid oxidizer was added. The biggest amplification of the mass combustion rate using the catalyst reached 5%.
Raman spectroscopy for studying the synthesis of conducting BC3 hetero-diamonds in diamond anvil cell under high temperature
Authors: Bykov A A , Zinin P V , Bulatov K M , Filonenko V P , Kutuza I B 
Published: July 2020

Abstract
A direct transformation of the sintered BC3 phase to a novel diamond-like d-BC3 phase was observed in a diamond anvil cell (DAC) at high temperature, 2500 K and high pressure, 22 GPa. For heating a specimen in a DAC a laser heating (LH) system combined with an acousto-optical filter and synchronized with a video camera was used. Combining the LH system with the acousto-optical filter allows measurement of the temperature distribution under infrared (1064 nm) LH of a specimen under high pressure in a DAC. The starting material with a composition BC3 was obtained by sintering a powder of nanodiamonds with a powder of boron microparticles at 6.0 GPa during 150 s heating at 1200 °C. The quenched BC3 specimen was studied by the Raman spectroscopy.
Crystal potentials and dispersion forces in additive approximation
Authors: Kyarov A Kh , Savintsev A P 
Published: July 2020

Abstract
On the basis of the additive approximation model, a formula for determining the van der Waals constant was obtained and the possibility of correctly describing the long-range part of the interaction potential of solidified inert gases crystals was indicated. Using the modified Lennard-Jones potential and experimental data on the dissociation energy and the equilibrium radius, the dispersion constants of systems of inert gas pairs and an alkali metal–inert gas are determined. The results of the calculations are in general agreement with the experiment.
Shear viscosity of n-pentane from diffusivity based molecular dynamics methods
Authors: Kondratyuk N D , Orekhov M A 
Published: July 2020

Abstract
The molecular dynamics methods for calculation of shear viscosity based on liquid diffusivity are tested against the classical Green–Kubo relation for n-pentane at 330 K and 0.601 g/cm3. The D-based method is shown to be as accurate as calculation of viscosity from the Green–Kubo formalism for pentane liquid. Stokes–Einstein relation is also in agreement with simulation results. However, it has much bigger uncertainty. The results of the simulation are in agreement with experimental data.
Influence of chemical composition of the surface layer on the nucleation of plasticity in CoCrFeMnNi high-entropy alloys
Authors: Korchuganov A V , Lutsenko I S , Zolnikov K P 
Published: July 2020

Abstract
The role of segregation of chemical elements upon free surfaces in the peculiarities of the plastic deformation mechanisms of thin films of the high-entropy CoCrFeMnNi alloy was clarified using a combined simulation of the Metropolis Monte Carlo and molecular dynamics. Irrespectively of surface orientation and stoichiometric composition of alloy Mn escapes to free surface and Fe goes to the bulk of the films. Ni also enriches the (111) surface while Co content is reduced. It is shown that for different compositions segregation reduces or decreases the elastic limit of the samples. In Co10Cr10Fe30Mn30Ni20 for all considered free surfaces, segregation equally influences the type and volume fraction of the formed defects. In Co30Cr30Fe10Mn10Ni20, they may remain the same or the mechanism of plastic deformation may change drastically in samples with segregation depending on the orientation of the free surface. Despite the redistribution of the volume fractions of various type defects, in general, the main mechanism for the development of plasticity in samples both before and after segregation is the growth of the hcp-bands. Change of defect structure in samples with surface segregation compared to samples with random distribution of elements is not necessary related to change of elastic limit.
Interaction of edge dislocation with copper atoms in an aluminum crystal
Authors: Fomin E V , Krasnikov V S 
Published: July 2020

Abstract
In this work, the interaction of the moving edge dislocation with obstacles in form of copper atoms is studied using the molecular dynamics simulations. The samples are aluminum monocrystals of 52 × 60 × 15 nm3 with axes oriented along directions [110], [111], [112]. The structure of copper solid solution is reproduced with following procedure: aluminum atoms are randomly selected and replaced by copper atoms. The concentration of copper atoms varies from 0.25% to 1%. The dislocation movement occurs under action of shear deformation. It is found that zones with a low concentration of copper atoms only slow down dislocation in an aluminum matrix, and the zones with a high local concentration of copper atoms not only produces stronger resistance to dislocation movement, but also they cause the change in the slip plane of the dislocation segment. When a significant part of a dislocation line moves to a neighboring slip plane, the complete transition of the dislocation to this slip plane can occur. It is also noted that such transitions of dislocation segments from one slip plane to another are accompanied by the formation of vacancies. Also the maximum value of the shear stress σxy
is estimated-its value is approximately 250 MPa.
Adhesion energy of ethane–graphite interface: Atomistic study
Authors: Iakovlev E S , Zhilyaev P A , Akhatov I Sh 
Published: July 2020

Abstract
Adhesion energy is an important characteristic of interfacial interactions. Usually one apply notion of adhesion energy to solid–solid interfaces, but it also could be extended to gas–solid and liquid–solid interfaces. In later case phenomenon of adsorption is closely related to the adhesion energy. In this work we apply molecular dynamics method to calculate the specific adhesion energy for gas and liquid ethane on a graphite substrate. Influence of temperature and density on the value of the specific adhesion energy is investigated. Langmuir adsorption model is applied to interpret results and establish connection between notions of adsorption heat and specific adhesion energy. Appearance of multilayer adsorption is detected for higher densities. Developed model and numerical approach to calculate adhesion energy and surface coverage can be applied for different types of the adsorbate and the substrate.
Bending vibrations of free and microdroplet-loaded graphene in the framework of the molecular dynamics method
Authors: Khokonov A Kh , Akhmatov Z A 
Published: July 2020

Abstract
Molecular dynamic (MD) modeling revealed that takes place swing up of transverse vibrations of graphene atoms with their transition to bending vibrations of membrane type. The amplitudes of such oscillations can reach large values, which considerably exceed the interatomic distances already for samples of micron sizes and amount to 10−2 from the length of the sample. The results of MD simulation were compared with the characteristic vibrational frequencies of graphene in the approximation of the tensioned membrane. The behavior of the graphene membrane during it loading with a liquid metal microdroplet has been considered also. Contact angles and relative stretching of the membrane outside and under the drop allow us to calculate the surface tension of the drop.
Determination of the effective emissivity distribution of a heated specimen using tandem acousto-optical tunable filter
Authors: Mantrova Yu V , Zinin P V , Bykov A A , Bulatov K M 
Published: July 2020

Abstract
We present the first experimental demonstration of a new imaging system for in-situ measurement the two-dimensional distribution of the effective emissivity and temperature of a heated specimen. In this work, we use the model of a gray body, assuming that the emissivity is constant over the entire wavelength range from 600 to 800 nm. Data acquisition was done using the laser heating (LH) system developed at the STC UI RAS. The LH system allows us to reach extremely high temperatures up to 6000 K at high pressures. The main component of the system is an imaging tandem acousto-optical tunable filter synchronized with a video camera. The maximal error of the emissivity measurement of the tungsten sample was found to be 13%, whereas the maximal error of the temperature measurements did not exceed 2%. An influence of different factors on the error of the emissivity determination is also discussed.
Experimental setup for determining the surface tension of highly curved interfaces by static and dynamic methods
Authors: Sergeev I N , Khokonov A Kh , Akhmatov Z A 
Published: July 2020

Abstract
Experimental devices and techniques for determining surface and interface tensions microdroplets of low-melting metals bordering with vacuum, liquid mediums and solid substrates have been described. Dynamic method is discussed for the gallium microliter sessile droplet immersed in water and a static method is considered for the tin microdroplet pending on a conical tip of a cantilever needle.
Simulation of the filtration process of hydrocarbon binary fluid with retrograde properties
Authors: Molchanov D A 
Published: July 2020

Abstract
This paper presents the results of the experimental studies of filtration modes of gas-condensate fluid using a binary mixture of methane–n-butane. It is shown that there is a possibility to obtain both the normal two-phase filtration mode and the self-oscillatory mode depending on the filtration conditions and the composition of the model mixture.
Flow bifurcation transitions of inelastic shear thinning fluids in a channel with sudden contraction and expansion
Authors: Roshchin D E , Kravchenko I V , Patlazhan S A 
Published: July 2020

Abstract
The bifurcation transitions from the symmetric to asymmetric flow regimes in shear thinning fluids in a channel with sudden contraction and expansion were studied by means of numerical simulations. On the example of the Carreau–Yasuda model, the bifurcation diagrams of shear thinning fluids with different viscosity flow curves were revealed along the critical Reynolds numbers of the bifurcation transitions. It was found that increase in variations of viscosity with shear rate leads to a noticeable decrease in critical Reynolds number and increase in dimensions of the angular vortices as compared to Newtonian fluids. The obtained results indicate the enhancement of flow instability of shear thinning fluids in channels with the variable cross-sections.
Microfibers formation in two-phase fluid flowing in a channel with the abrupt constriction: Numerical modeling
Authors: Kravchenko I V , Patlazhan S A , Sultanov V G 
Published: July 2020

Abstract
Numerical modeling was used to study the patterns of droplet deformation in two-phase Newtonian fluids flowing through a three-dimensional rectangular microchannel with a sharp narrowing. The elongation of single droplets of different viscosities was investigated in different channel zones. Calculations were carried out for different confinement parameter—the ratio of droplet diameter to the gap thickness. The increase in this parameter was shown to lead to the substantial increase in the droplet relative elongation. The effect of coalescence to microfiber formation in flowing emulsion was considered.
Numerical simulation of the fiber spinning with the viscoelastic Giesekus constitutive model
Authors: Kravchenko I V , Vagner S A , Sultanov V G 
Published: July 2020

AbstractThe numerical simulation of the first stage of fiber-spinning process was performed. The single-mode Giesekus model was used for polymer fiber stress calculations. Fiber profiles, longitudinal velocity, tensile stress and apparent elongational viscosity were analyzed depending on the stretch speed and the degree of anisotropy of the polymer.
Influence of an electric field on Rydberg nD states of cold lithium atoms
Authors: Bronin S Ya , Bobrov A A , Fomichev D E , Saakyan S A , Sautenkov V A , Zelener B B , Zelener B V 
Published: July 2020

Abstract
Influence of a weak electric field on the coherent Rydberg resonances was studied on two-photon transitions 2S–nD by recording the resonance fluorescence of lithium atoms in a magneto-optical trap. It was observed that an isolated spectral line 2P–nD transferred to the spectral band width growing with a principal number n (or an electric field E). It was shown that the frequency tuning of a resonant radiation on the left (right) edge of the band allows to create a gas of Rydberg atoms with fixed and large dipole moments d ∝ ea
0
n
2 (e is the elementary charge, a
0 is the Bohr radius), oriented against (along) the electric field. The radiation frequency was tuned on the center of the band would produced atomic states with zero dipole moments, but with a big contribution of states with maximum angular momentum quantum number l ~ n.
Numerical study of energy loss rate of fast proton in cold dense electron gas in strong magnetic field
Authors: Bobrov A A 
Published: July 2020

Abstract
Energy loss of a proton propagating through a low-temperature gas of magnetized electrons is studied by molecular dynamics method for the case when proton velocity is much more than electrons thermal velocity. Strong uniform magnetic field is considered when electron Larmor radius is much smaller than distance of closest approach (Coulomb radius). High electron density, and hence small values of the Coulomb logarithm, is considered. The dependence of energy loss on angle between the proton velocity and the magnetic field direction is studied. Results of calculations are compared to Derbenev and Skrinskii theoretical approach to average friction force.