Asymptotics of a step-like contrast structure with a multizonal interior layer
Asymptotics of a step-like contrast structure with a multizonal interior layer
R. E. Simakov
A boundary value problem for a singularly perturbed system of two second order ODEs with different degrees of the small parameter at the second derivatives is considered. The peculiarity of the problem is that one of the two equations of the degenerate system has three disjoint roots, two of which are double, and the third is simple (single). It is proved that for sufficiently small values of a small parameter, the problem has a solution with a fast transition from one double root of the degenerate equation to another double root in a neighborhood of some interior point of the segment. A complete asymptotic expansion of this solution is constructed and substantiated. It differs qualitatively from the well-known expansion in the case when all the roots of the degenerate equation are simple. In particular, the expansion is carried out not in integer but in fractional powers of the small parameter, the boundary layer variables have a different scale, and the transition layer turns out to be eight-zone.
Show AbstractFiltration and rheological characteristics of low-permeability reservoir rocks when modeling directional unloading method
Filtration and rheological characteristics of low-permeability reservoir rocks when modeling directional unloading method
V. I. Karev, Yu. F. Kovalenko, V. V. Khimulia
This work is devoted to the study of rheological, deformation and filtration properties of low-permeability rocks of Achimov deposits of the Urengoy gas condensate field using the directional unloading method. As part of the study, physical modeling of the real stresses in the vicinity of the well was carried out when implementing the directional unloading method. Experiments were conducted by using the unique facility, Triaxial Independent Load Test System of the Institute for Problems in Mechanics of the Russian Academy of Sciences. Modeling was carried out for two types of bottomhole design: an open hole and a perforation tip in a cased hole. The dependence of the filtration properties of rocks on the type of stress-strain state is shown; conclusions are drawn about the nature of creep. The values of pressure drawdown, which leads to an increase in the permeability, are determined. The results obtained indicate that the directional unloading method can be successfully applied to wells drilled in the Achimov deposits.
Show AbstractCharacteristics of a quasi-stationary pulsating transverse-longitudinal discharge in high-speed propane-air flows
Characteristics of a quasi-stationary pulsating transverse-longitudinal discharge in high-speed propane-air flows
I. K. Nesterenko, K. N. Kornev, A. A. Logunov, V. M. Shibkov
The paper considers the prospects of using a quasi-stationary pulsating discharge to control the process of supersonic combustion of hydrocarbon fuels. The discharge characteristics have been obtained experimentally under conditions of subsonic and supersonic air flow. Supersonic steady combustion of propane in expanding aerodynamic channels of various configurations has been implemented. The results obtained confirm the efficiency of using low-temperature plasma in supersonic plasma aerodynamics.
Show AbstractStudy of the influence of dynamic and thermal characteristics of the atmospheric boundary layer on atmospheric air pollution in the Moscow metropolis
Study of the influence of dynamic and thermal characteristics of the atmospheric boundary layer on atmospheric air pollution in the Moscow metropolis
K. V. Rodina, E. G. Semutnikova
This article focuses on assessing the impact of wildfires and adverse weather conditions on air pollution in Moscow. The article examines in detail the case of aerosol pollution of the smoky atmosphere of the Moscow region in July 2016. The main indicators of wildfire investigated in this work are particulate matter PM10 and PM2.5. Calculations of the main statistical characteristics of PM10 and PM2.5 concentrations are presented: the average value, median and mode and pair correlation coefficients separately for PM10 and PM2.5 between different stations and between PM10 and PM2.5 at one station for the entire period of 2016 and 2018 as well as for the smoke period in July 2016 and the period with bad weather conditions in September 2018. The diurnal course under smoke is analyzed in comparison with the typical course in the warm period and in the bad weather conditions. Based on the intra-day dynamics of PM10 and PM2.5 concentrations in July 2016 and September 2018 the dependence of pollution on the thermal stratification of the atmospheric boundary layer is considered. The dependence of aerosol concentrations on the wind speed in the atmospheric boundary layer is analyzed.
Show AbstractDependence of the yields of spectator neutrons and protons in $^{208}$Pb-$^{208}$Pb collisions on the thickness of the surface neutron layer
Dependence of the yields of spectator neutrons and protons in $^{208}$Pb-$^{208}$Pb collisions on the thickness of the surface neutron layer
N. A. Kozyrev$^{1,2}$, U. A. Dmitrieva$^{1,2}$, A. O. Svetlichnyi$^{1,2}$
The influence of the thickness of the surface neutron layer in $^{208}$Pb on the yields of spectator nucleons in $^{208}$Pb-$^{208}$Pb collisions at relativistic energies at the Super Proton Synchrotron (SPS) and Large Hadron Collider (LHC) is estimated by means of the Abrasion-Ablation Monte Carlo for Colliders (AAMCC) model developed by the authors. AAMCC predicts the formation of spectator matter bound into fragments as well as free spectator neutrons and protons as a function of collision impact parameter. As shown for the first time by simulating collisions of nuclei with different thickness of the surface neutron layer, an excess of surface neutrons in $^{208}$Pb leads to a noticeable increase in the number of spectator neutrons relative to the number of spectator protons in central nucleus-nucleus collisions. With a typical excess of surface neutrons, known from theory and experiments at low energies, the model also predicts a doubling of the cross sections for the production of a certain number of neutrons in central events without the emission of spectator protons. In view of the discrepancy between the data on the surface neutron layer obtained by various experiments, the study of the yields of spectator nucleons in collisions of relativistic nuclei can be proposed as a new research method. Such measurements can be performed in the ALICE experiment at the LHC equipped with forward hadron calorimeters to register spectator neutrons and protons.
Show AbstractInformation-entropy inequalities for pure states of quantum systems in the probabilistic representation of quantum mechanics
Information-entropy inequalities for pure states of quantum systems in the probabilistic representation of quantum mechanics
A. P. Bykov$^1$, V. I. Man'ko$^{1,2}$
Due to the rapid development of technologies, more and more experiments are being carried out every year in the field of quantum optics, quantum computing and cryptography, therefore the relevance of works on quantum information theory is beyond doubt. In this paper, we studied information-entropy inequalities for pure states of quantum systems, and, in particular, considered inequalities for a one-dimensional harmonic quantum oscillator. A symplectic quantum tomogram of pure states in the probabilistic representation of quantum mechanics is obtained. The tomographic Shannon entropy is introduced and new expressions for the tomographic entropy of pure states of a one-dimensional quantum harmonic oscillator are obtained, as well as exact expressions for the ground and first excited states depending on the actual parameters, a shift in the first excited state by the Euler - Mascheroni constant is obtained. Numerical methods were also considered for obtaining approximate values of the tomographic entropy of the second and third excited states, at fixed parameters. The expected growth of the tomographic entropy with an increase in the level was obtained depending on the actual parameter. The approach presented in the course of this work can be extended to the question of the entropy of arbitrary Fock states, as well as coherent states of a parametric quantum oscillator. This direction of research is of interest and will be developed in future works.
Show AbstractApproaches to optimizing the burnup depth using radial fuel rod profiling
Approaches to optimizing the burnup depth using radial fuel rod profiling
R. A. Vnukov, I. A. Zhavoronkova, V. V. Kolesov, G. V. Karpovich
This paper raises the question of the optimal use of resources in the process of nuclear fuel burnup. Optimization tasks boil down to a possible reduction in the resources used while maintaining the current characteristics or extending the campaign by using the same amount of resources. As a solution to the simulated problems, profiling of fuel pellets with a burnable absorber is proposed. Profiling is carried out in proportion to the radial burnup of the fuel rod relative to the average value. The use of this technology in standard fuel assemblies is of interest from the standpoint of ensuring safety and improving technical and economic characteristics. The calculations were carried out in the Serpent software package, which performs precision neutron-physical calculations by the Monte Carlo method. Compared to a standard assembly, the increase in keff in the middle of the fuel campaign provides more flexibility during the operation of the reactor plant in the moments before refueling. Profiling had no effect on the length of the fuel campaign. The impact on reactor campaigns allows us to conclude that the technology can be used to optimize fuel enrichment and extend the fuel campaign or reduce the use of a given boric acid concentration at the beginning of the campaign.
Show AbstractОсобенности 2D-бифуркаций для структур с квантовыми точками из коллоидного золота, обладающих свойствами метаматериала
Особенности 2D-бифуркаций для структур с квантовыми точками из коллоидного золота, обладающих свойствами метаматериала
V. C. Zhukovsky$^1$, V. D. Krevchik$^2$, M. B. Semenov$^2$, P. V. Krevchik$^2$, D. A. Saburova$^2$, I. M. Semenov$^2$, A. D. Smirnova$^2$, I. A. Rubtsov$^2$, I. S. Antonov$^2$
In framework of the 2D - dissipative tunneling theory in approximation of a rarefied gas of the «instanton - antiinstanton pairs» at a finite temperature under the conditions of an external electric field, the features of tunneling transport for planar structures with quantum dots (QDs) from colloidal gold, that have metamaterial properties, have been studied. It was experimentally shown that, depending on the positioning of the cantilever needle of a combined atomic force and scanning tunneling microscope (AFM / STM), either above a single quantum dot or between two neighboring quantum dots, either a single or double effect of 2D tunneling bifurcations have been observed, respectively. It is such a double bifurcation regime, as our theoretical model has shown, that is associated with the manifestation of the metamaterial properties by the structure under study. A convincing qualitative agreement between the experimental I – V characteristics and the field dependence of the 2D - dissipative tunneling probability in the two studied modes, taking into account the observed quantum beats in the vicinity of the 2D bifurcation points, has been obtained.
Show AbstractHamiltonian constrained formalism for the general field theories with unfree gauge symmetry
Hamiltonian constrained formalism for the general field theories with unfree gauge symmetry
V. A. Abakumova, S. L. Lyakhovich
We consider constrained Hamiltonian formalism with any finite order of constraints for general field theory with unfree gauge symmetry. It is noticed that the redefinition of the Hamiltonian by adding constraint terms, as well as the linear combination of constraints of all generations, does not change the gauge identities, and therefore the unfree gauge symmetry transformations. The general formalism is exemplified by the model of linearized unimodular gravity, for which the triviality of a cubic vertex, proportional to the completion function of a free theory, is also demonstrated in the Hamiltonian formalism.
Show AbstractSensitive to light scalars $B\to K^*l^+l^-$ angular observables in NMSSM
Sensitive to light scalars $B\to K^*l^+l^-$ angular observables in NMSSM
A. I. Mukhaeva$^1$, A. V. Bednyakov$^{1,2}$
In this work we consider NMSSM scenarios with light (pseudo) scalars, which have masses ranging from 10 to 100 GeV. The main goal of the study is to revisit the invariant mass squared of the lepton pair q^2-dependent angular B -> K^*l^+l^- observables, which are sensitive to scalar contributions, and estimate the magnitude of the latter in the considered scenarios. In addition, prospects of experimental study of the effects are discussed.
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