bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multy-cascade enrichment schemes for reprocessed uranium recycling
Authors: Gusev V E 
Published: December 2020

Abstract
This paper deals with the problem of reprocessed uranium (RepU) enrichment in cascades of gas centrifuges with simultaneous fulfillment of requirements on concentrations of isotopes 232,234,236U. These harmful isotopes bred by nuclear chain reaction are responsible for an increase in radioactivity level and neutron poisoning of fresh nuclear fuel. The study examines the cascade schemes that aim at closing the nuclear fuel cycle by satisfying the formal condition of the complete uranium reclaim. The prospective VVER fuel cycle strategy of multiple uranium recycling is considered. Schemes under consideration are multi-cascade ones. Such configurations are necessary to fulfill both a series of requirements on concentrations of even-numbered isotopes in commercial low-enriched uranium and condition of ‘full return’ of uranium extracted from spent nuclear fuel from particular reactor to produce fresh fuel load for the same reactor. The research provides a basis for comparison between three various multi-cascade schemes designed to re-enrich RepU under mentioned above conditions. The unified metrics (related to ordinary cascade and normalized to LEU product) of natural uranium savings, separative work, and depleted uranium consumption and their derivative, we used. The calculations take into account the necessity of RepU dilution to compensate for the adverse effects of 232,234,236U isotopes. As the reference cascade scheme, a simple modification of a single triple-flow cascade for RepU enrichment was considered. It is demonstrated that some modern cascade schemes could provide repetitious recycling of uranium.
Optimization of a system of square cascades for efficient concentration of intermediate isotopes
Authors: Azizov T E , Smirnov A Yu , Sulaberidze G A , Mustafin A R 
Published: December 2020

Abstract
The problem of obtaining relatively high concentrations of stable isotopes of intermediate mass numbers is considered. The object of research is a connection of three ordinary square cascades. The possibility of simultaneous concentration of isotopes of intermediate masses in different output flows of cascades is shown. The dependencies of the parameters of the cascade schemes under consideration are investigated. The method of optimization of such system of square cascades according to the criterion of minimum relative total flow at given concentrations of target components is proposed. Calculations were made on the example of isotope mixtures with the number of components 4 and 5.
Production of highly concentrated intermediate molybdenum isotopes in optimal cascade with two additional product flows
Authors: Palkin V A , Maslyukov E V , Lubnin S S 
Published: December 2020

Abstract
The problem of highly concentrated molybdenum isotopes production in multiflow cascades is considered. A method of the cascade with two additional product flows optimization has been developed. Two components intermediate in weight are concentrated simultaneously in those flows. The optimization problem is solved using a variation of the partial flow cuts of the cascade stages with large separation coefficients. The optimization criterion is the minimum of the stage total feed flow while ensuring a given concentration of isotopes. A computational experiment was carried out to separate a mixture of molybdenum hexafluoride. The experiment demonstrated the features of intermediate components concentrating in additional product flows of the cascade.
Optimal working regimes of the hyper-speed long Iguasu gas centrifuge
Authors: Bogovalov S.V. , Borman V.D. , Vasilyev A.V. , Tronin I.V. , Tronin V.N. 
Published: December 2020

Abstract
Rapid development of technologies for production of new materials may provide design of gas centrifuges (hereafter GC) with rotor speed above 1000 m/s. The question about efficiency of such GCs remains open. At present no experimental or theoretical studies regarding the separation effciency of such GCs exist. We present the results of calculations of the optimized separative power of the hyper-speed Iguassu GCs with a length of 1 to 5 meters and rotational speeds from 1000 to 1500 m/s. The calculations were performed in axisymmetric approximation in frameworks of the source-sink model. It is shown that for the hyper-speed GCs the optimized separative power, pressure at the rotor wall, feed flux and gas friction power linearly grow with the rotor length, while the temperature drop along the rotor does not depend on the rotor length.
Automatic optimization of working modes of a gas centrifuge for isotope separation
Authors: Juromskiy V M , Borisevich V D 
Published: December 2020

Abstract
The adaptive algorithms for the automatic search for the optimum separative power of a single gas centrifuge (GC) depending on the pressure of the working gas near the wall of the working chamber are studied. It is demonstrated that the proposed control system is insensitive to the displacement of the found optimum of the separative power, a change in the shape of the extremum, including deformation of the “plateau” in the maximum region, as well as the additive errors of the technical means measuring the GC separation ability
Production of high-enriched carbon-13 by two-stage laser method
Authors: Laptev V B , Pigulsky S V , Mezhevov V S 
Published: December 2020

Abstract
A variant of a two-stage laser process for production highly enriched carbon-13 (13C) with a concentration of more than 99% is being investigated. The first laser stage provides effective enrichment of 13C up to 30-50% based on the isotopically selective multiphoton dissociation of freon-22 (CF2HCl) by pulsed radiation of a CO2 laser. Then the product of the first stage tetrafluoroethylene, enriched in 13C, is converted into the working substance of the second stage, freon-12B2 (CF2Br2). At the second stage of enrichment, a component with an undesirable isotope 12C undergoes to selective dissociation, until its concentration in the residual gas decreases to 1% and the concentration of the 13C isotope is increased to 99%. In preliminary experiments, high parameters of the elementary act of separation were achieved - the dissociation yield of the 12CF2Br2 up to 20% and selectivity (for 12C) up to 100. A productivity of the second enrichment stage for a reactor of ideal displacement is estimated, that is 0.6 and 1.2 g13C/h for initial concentrations of 13CF2Br2 30 and 50%, respectively.
Application of the perturbation theory for the calculation of thermodynamic and transport properties of hydrogen and its isotopes
Authors: Bogdanova Yu A , Maklashova I V , Gubin S A , Vagina U D 
Published: December 2020

Abstract
In this paper, we analyzed the analytical relationships in the literature to calculate the viscosity coefficient obtained from the Chapman-Enskog kinetic theory using the Lennard-Jones pair interaction potential. In the proposed formulas for calculating the viscosity of individual substances, there are values of the radial distribution function and the hard-sphere diameter. These quantities were obtained using a technique developed previously by the authors based on the perturbation theory used to calculate the thermophysical properties of substances
Automatic system of temperature control at laser cladding
Authors: Glova A F , Lysikov A Yu , Nelyubin S S , Klochkov I D , Baldaev L K , Novinkin Yu A , Stogov M A 
Published: December 2020

Abstract
An automatic system for monitoring the true temperature of the surface of a heated body based on a small-sized spectrometer has been developed and created. The system operates in real time with a speed of 30 ms. The system has been tested in laboratory conditions and tested in pilot production with laser cladding of metal powder.
Controlled processes at laser coating deposition
Authors: Glova A F , Lysikov A Yu , Nelyubin S S , Klochkov I D , Baldaev L K , Novinkin Yu A , Stogov M A 
Published: December 2020

Abstract
A description of the method is given of coating deposition under irradiation with a horizontal laser beam of a gas-dust medium which is an ensemble of micro-particles moving in the gas in the form of a free vertical jet. A number of coatings are obtained on various substrates and the results of measurements of their characteristics are presented. A setup based on a cw CO2-laser for the synthesis of diamond coatings in optical discharge plasma in the laser plasmatron mode has been created. The effect of spherical lens aberrations on the discharge maintenance thresholds is established. A diamond film was obtained on the surface of a tungsten substrate when a plasma jet was expelled into atmospheric air. An automatic system for measuring surface temperature in real time has been developed and created. The system was tested for laser cladding of metal powder in a pilot production.
Impact of the pre-deposited surface charge on the breakdown in a dielectric barrier discharge in the air
Authors: Akishev Y , Karalnik V , Petryakov A , Shao T , Zhang C 
Published: December 2020

Abstract
The electrical charge deposited on a dielectric barrier of dielectric barrier discharge (DBD) changes markedly the configuration and strength of the local electric field both on the barrier and in the gas gap. In turn, a change in the local electric field affects the rate of ionization multiplication of electrons in this area and, accordingly, influences the breakdown conditions providing the appearance of microdischarges in a barrier discharge. The features of the DBD breakdown in the presence of the pre-deposited charge on a dielectric barrier were investigated by the example of the plane-to-plane DBD operating in the ambient air at atmospheric pressure. The electric charge deposition on the barrier was performed in advance with the use of the pulsed pin-to-plane barrier corona. Corona discharge allows one to control both the amount and location of the pre-deposited charge. The slow increasing voltage of the needed polarity was used to initiate the breakdown in the plane-to-plane DBD. The slow increasing applied voltage provides the multiple breakdowns forming the “one by one” sequence of MDs. The analysis of the obtained results was performed on the base of the conception of the necessary and sufficient conditions for the MDs formation.
Electron transport in dense degenerate plasmas
Authors: Filippov AV 
Published: December 2020

Abstract
Within a unified approach, a method for calculating the tensors of electrical conductivity, the Seebeck coefficient and thermal conductivity of a nonideal plasma in a magnetic field were considered. Under this unified approach the kinetic coefficients are calculated together with the equation of state for a nonideal plasma within the framework of a quasi-chemical model. Various methods for determining the Coulomb logarithm in the kinetic theory of transport and various options for choosing the boundary value of the wave number of electrons are considered. The scattering of electrons by ions using the phase shift method has been considered and the appearance of values of the Coulomb logarithm less than unity are demonstrated. Electron scattering by the phase shift method is considered using the Buckingham potential which permits to describe the Ramsauer minimum in the transport cross section for electron scattering by noble gas atoms.
Experimental studies of the electrical and radiative characteristics of a channel surface discharge
Authors: Kotov A A 
Published: December 2020

Abstract
Channel surface discharge (CSD) is a type of surface (sliding) discharges or dielectric barrier discharges in the incomplete stage. Experimental results of both incomplete (low-current) and high-current complete stages of the CSD are presented. The waveform of current pulse in the discharge incomplete stage as well as the influence of the voltage growth rate dU/dt on the discharge electrodes on waveform are studied. Experimental dependence of the CSD current pulse amplitude on the dU/dt rate is obtained in the incomplete stage over a wide range of variation of the dU/dt. For the CSD complete stage, the relation between the intensity of the discharge radiation in the UV region and the amplitude of the current pulse has been received. The dependence of the maximum electron concentration on the UV radiation intensity of the high-current stage CSD was obtained for the case when UV radiation from the CSD was used for ionization of atmospheric pressure nitrogen.
Energy of low-temperature synthesis of graphen-like carbon nanocomposites on porous silicon (Review)
Authors: Tynyshtykbayev K , Insepov Z 
Published: December 2020

Abstract
The process of low temperature synthesis of graphene-like nanocomposites films on the porous silicon nanocrystallites (nc-PS) is considered. It was shown that the low temperature synthesis of graphene-like nanocomposites on nc-PS is due to the excess surface energy of porous-Si nanocrystallites and, in this case, nanoscale effects that occur on local parts of the atomically rough nc-PS surface play a specific role. In the report features of the specific role of the atomically rough nc-PS forces and the influence these forces on the energy of low-temperature synthesis of graphene-like nanocomposites on the surface of porous silicon nanocrystallites are considered.
Numerical modelling of water hammer with cavitation
Authors: Sumskoi S I , Sverchkov A M 
Published: December 2020

Abstract
A new numerical method for solving a system of one-dimensional nonstationary equations describing the flow with cavitation is presented. The method is based on the Godunov approach. The method is implemented taking into account the cavitation that occurs in the flow. Test calculations have shown the acceptable accuracy of the method and its ability to describe phase transitions in the flow.
Simulation of the Intrusion Process and Extrusion of Non-Wetting Liquid From Porous Media in Quasi-Static Mode
Authors: Byrkin V A , Geraseva A V 
Published: December 2020

Abstract
To understand the thermodynamics, transport and physical phenomena in porous media today, the most effective way is to use various models of porous media and conduct numerical experiments on their basis. It has been shown that such models are an effective tool for research of transport processes from the local scale at the level of individual pores to the level of individual granules. The approach proposed in this paper is based on numerical calculations based on known theoretical approaches. The principal difference from the previously used approaches and novelty lies in the absence of simplifications associated with the narrowing of the distribution of pores in size and the number of nearest neighbors, which allows us to take into account in detail the possible geometric configurations, when the pore of the same radius can be surrounded by a different number of neighboring pores. In addition, the use of numerical modelling allows us to obtain a large number of different parameters, ranging from structural characteristics (the number of nearest neighbors, connectivity, etc.), cluster (percolation thresholds) and ending with volume dependencies on pressure and time and the visualization of filling processes.
Hysteresis of Percolation Transition and Relaxation of Fast and Slow States of the System Nanoporous Medium - Non-Wetting Liquid
Authors: Belogorlov A A , Borman V D , Bortnikova S A , Byrkin V A , Tronin I V , Tronin V.N. 
Published: December 2020

Abstract
In the present paper we present the results of experimental and theoretical studies of intrusion-extrusion and relaxation of non-wetting liquid in three Fluka porous media. New data on hysteresis of intrusion-extrusion and dependence of the degree of filling of a porous body on time in the process of extrusion were obtained experimentally. It has been established that in all the conducted experiments the liquid extrusion took place in two stages: at the first stage of fast relaxation the characteristic time of outflow is several seconds, at the second stage of slow relaxation the characteristic time is several hundred seconds. The experimental data obtained are described in the theoretical model [1]. For the studied porous media, the existence at the initial moment of time of local states with short leakage times (a few seconds or less) and states with large leakage times (hundreds of seconds) was established. Porous bodies in which the coexistence of fast and slow states at the initial moment of time is established are investigated for the first time.
Study of Constant Filling Pressure Conditions in a System “Nanoporous Medium - Non-wetting Liquid” in an Impact Process
Authors: Khlistunov I A , Belogorlov A A , Borman V D 
Published: December 2020

Abstract
In this work critical constant filling pressure conditions for systems “nanoporous medium - non-wetting liquid” under impact were studied. To determine the conditions influencing on the occurrence of a constant filling pressure, a series of impact experiments have been carried out on four porous media with distilled water as non-wetting liquid. On the basis of the obtained experimental data for the systems under investigation, a method for determining the flow rate of liquid in the pores was developed and its values for the systems under investigation in a given range of impact energies were determined. It is shown that the liquid flow rate in the pores is one of the key parameters determining the presence of a constant critical filling pressure. It was also found that in the investigated energy range the liquid flow rate increases and goes to limit with increasing impact energy.
Study of the model system for delivery and controlled release of anticancer drugs in affected areas.
Authors: Belogorlov A A , Bortnikova S A , Kulakov S A , Mingalev P G , Akopdzhanov A G , Shimanovskii N L 
Published: December 2020

Abstract
The modern clinical oncology key task is to increase the efficiency of anticancer chemical therapy. The main direction of provided investigations are to ensure targeted delivery of drugs to cancer cells with the minimization of the harmful effect to normal cells, as well as overcoming the multiple drug resistance of cancer cells. One of the possible solutions is to use nanoporous medium filled with non-wetting liquid (drug) as a carrier. Interest to such systems is caused by two effects observed for such systems: the effect of non-wetting liquid dispersion in pores and it’s anomalously slow relaxation (outflow). It has also been shown that these effects are critically dependent on temperature. The work is present results of experimental study of the kinetics of model liquid outflow from nanoporous medium at the temperature range 20-40 °C. Results obtained for systems with different granule sizes and surface modifications.
Study of sorption properties of HF 512O and NaX synthetic zeolites in the process of sorption of air mixture components
Authors: Tishin A A 
Published: December 2020

Abstract
The sorption properties of synthetic zeolites HF 512O and NaX were studied. In the course of the study, the volume method obtained the sorption capacities of zeolites for nitrogen and oxygen. The experimental setup for determining the sorption capacity by volumetric method consisted of two tanks. The first tank has a known volume, and the second tank is filled with the studied sorbent. Helium was used to determine the free volume of the second tank. The gas sorption capacity of which must be determined is fed to the first tank, the second tank is pumped out using a vacuum pump, after which the tanks are connected and the separation in the tanks is leveled. Thus, the sorption capacity of the sorbent can be calculated based on the pressure drop in the system. The selectivity of sorbents for the nitrogen – oxygen pair for pure gases was calculated.
Modeling and Comparison with Experiment of SAW Induced Water Droplet Motion
Authors: Zhakiyev N , Tynyshtykbayev K , Insepov Z 
Published: December 2020

Abstract
A water droplet motion on a piezoelectric substrate, which is actuated using Surface Acoustic Waves (SAW), is presented toward water desalination purposes. The processes of fluid flow motion under different RF powers and SAW frequencies, induced by internal streaming, has been observed both experimentally and numerically. A free droplet dynamics in the volume of 2 and 5 μl interacted with intensive SAW on the piezoelectric substrate surface for 34 and 58 MHz frequencies, and power output between 0 - 4 dBm observed. In tha paper a three-dimensional (3D) finite element model using computational fluid dynamics approach of the free water droplet motion was developed. The different dependences of microfluidic performance such as locally streaming lines, slip length and droplet motion velocity have been studied.
Effect of polymer matrix on characteristics of percolation cluster composed of MWCNT
Authors: Eremin Yu S , Grekhov A M 
Published: December 2020

AbstractMixed matrix membranes (MMMs) with unique transport characteristics can be prepared by the addition of the minor amounts of carbon nanotubes. The paper presents the results of study gas permeability (O2, N2, CH4) for poly(vinyltrimethylsilane (PVTMS) and Poly(methyl methacrylate) (PMMA) with embedded multiwall carbon nanotubes (MWCNT). The paper shows how the choice of a polymer matrix affects the parameters of a percolation cluster from CNTs.
Synergy of selective gas transport in bilayered membranes
Authors: Bakhtin D S , Borisov I L , Polevaya V G , Budd P M , Volkov A V 
Published: December 2020

Abstract
Dense bilayer PTMSP/PIM-1 membranes and PTMSP/PIM-1 blends were prepared and studied in order to obtain insight into the recently observed synergistic effect of increased CO2/N2 selectivity for thin-film composite (TFC) membranes consist of PIM-1 (selective layer) and PTMSP (gutter layer). It was shown that the mixing of these two polymers does not lead to a synergistic effect in gas permeance, since dense films made by blending of PIM-1 and PTMSP showed classical trade-off permeation/selectivity behavior. Analysis of gas-transport property data using a bicomponent resistance-in-series model allowed us to conclude that the increased N2 transport resistance of the layer formed on the border of the two polymers is presumably responsible for the increased ideal selectivity.
Characterization of porous polyacrylonitrile membranes by liquid-liquid displacement technique
Authors: Balynin A V , Yushkin A A , Efimov M N , Muratov D G , Volkov A V 
Published: December 2020

Abstract
In this work, series of PAN membranes were prepared by the combined VIPS/NIPS method using different solvents. These membranes were investigated by using liquid-liquid displacement method for membrane pore size distribution and membrane permeance measurements. Wide range of pores size (30-60 nm) and membrane permeance up to 400 L/m2·h·bar were achieved depending on the casting conditions. It was shown that longer exposure in water vapor leads to higher pore size and at the same time makes membrane less permeable due to low asymmetry of porous structure..