Water Formation in Asteroids
Water Formation in Asteroids
A. Yu. Dubinsky$^1$, S. I. Popel$^1$, J. S. Reznichenko$^{1,2}$
The issue of the formation of water molecules in asteroid regolith is considered. The possibility of oxygen atoms release as parts of silver hydroxide molecules from the crystal lattice of silicon dioxide in regolith has been demonstrated. Silver hydroxide, in turn, can react with hydrogen relatively easily, resulting in the formation of water and silver. This demonstrates the possibility of the formation of water molecules included in the near-surface soil of an asteroid. The proposed mechanism for the formation of water molecules does not require such an unlikely event as two solar wind protons hitting the same point. In the situation under consideration, it is only required that the end of the proton track fall in the region where the elements of the quartz lattice, for example, metal sulfide, are in contact with each other. The presence of water molecules in the soil of an asteroid can affect the photoelectric properties of its regolith and the parameters of the plasma-dust system above the asteroid. A way to identify the nature of the formation of water on an asteroid can be a combination of the method of finding water on asteroids, based on the detection of dust near the surfaces of these space objects, as well as a method using the detection of neutron fluxes passing through areas of the surface of the space body.
Show AbstractNarrow-linewidth IR laser modulation by quantum cascade laser structure
Narrow-linewidth IR laser modulation by quantum cascade laser structure
S. A. Chakhlov$^{1,2}$, L. A. Miklashevich$^1$, A. A. Lastovkin$^1$, N. G. Zakharov$^1$
The effect of modulation of narrow-linewidth laser radiation in the 1590 nm range, passed through the waveguide structure of a quantum cascade laser, is obtained, observed when applying an electric voltage to the structure. This effect reveals the thermodynamics of the active region of a quantum cascade laser operating in a pulsed mode, which is relevant in the problem of optical communication implemented on the principle of high-frequency amplitude signal modulation.
Show AbstractNeural networks assisted reconstruction wavefront of laser radiation based on intensity profile near focus of converging lens
Neural networks assisted reconstruction wavefront of laser radiation based on intensity profile near focus of converging lens
N. V. Iakushkin$^{1,2}$, A. V. Mitrofanov$^{1,2,3}$, A. V. Vasil'ev$^1$, A. V. Larichev$^{1,3}$, N. G. Iroshnikov$^1$, D. A. Sidorov-Biryukov$^{1,2,3}$
The architecture ConvFormer S18 network allows reconstruct the shape of the laser radiation wavefront from the intensity distribution near the lens focus. The use of normilizing method for sparse data can reduce RMS error of wavefront reconstruction by the factor of 2. Ability of neural network to reconstruct laser radiation wavefront based on its intensity profile near focus of converging lens is experimentally demonstrated for set of abberations applied simultaneosly. RMS-error of wavefront reconstruction in the experiment from the intensity distribution taken behind the focus, in front of the focus, and from the data from both positions were estimated as 𝜆/18 , 𝜆/13 and 𝜆/31. The correctness of the technique is proven by the coincidence of the calculated intensity distribution based on data obtained by the neural network with the measured experimental values.
Show AbstractTheoretical calculations of $^{161}$Tb production on dysprosium isotopes
Theoretical calculations of $^{161}$Tb production on dysprosium isotopes
N. Yu. Fursova$^{1,2}$, R. A. Aliev$^3$, S. S. Belyshev$^{1,2}$, A. A. Kuznetsov$^{1,2}$
In the present work, based on the combined model of photonucleon reactions, the activities of the promising medical isotope $^{161}$Tb produced by the $^{162}$Dy($\gamma$,1p) and $^{163}$Dy($\gamma$,1n1p) reactions were calculated for electron beam energies ranging from the reaction threshold to 55 MeV. Photonuclear isotope production also requires information on the formation of side nuclides, so the reactions $^{162}$Dy($\gamma$,1n1p), $^{163}$Dy($\gamma$,1p) and $^{163}$Dy($\gamma$,2n1p) were studied. The results of calculations indicate the possibility of using the monoisotopic target of $^{162}$Dy at electron beam energies of 21-22 MeV and the monoisotopic target of $^{163}$Dy at energies of 29-30 MeV for photonuclear production of $^{161}$Tb.
Show AbstractPrediction of viscosity of binary mixtures of hydrocarbons and carbon dioxide using the Lorenz–Bray–Clark model
Prediction of viscosity of binary mixtures of hydrocarbons and carbon dioxide using the Lorenz–Bray–Clark model
E. E. Volodina, A. V. Isaeva
The article shows the feasibility of using the direct energy minimisation method in conjunction with the Peng-Robinson equation of state and the Lorenz-Bray-Clark model to calculate the density and viscosity of binary hydrocarbon mixtures, as well as mixtures of hydrocarbons with carbon dioxide. The accuracy of the numerical simulation results was assessed by comparing the calculated values of the density and dynamic viscosity of the phases (liquid and gas) with experimental data published in the literature. It is shown that the approach considered in the article makes it possible to predict with good accuracy (up to 10 %) the values of density and viscosity of phases for binary hydrocarbon mixtures, which include components containing up to eight carbon molecules.
Show AbstractCausal relations between climate and carbon cycle taking into account natural climate variability and economic cyclicity of greenhouse gas anthropogenic emissions into the atmosphere
Causal relations between climate and carbon cycle taking into account natural climate variability and economic cyclicity of greenhouse gas anthropogenic emissions into the atmosphere
K. E. Muryshev$^{1,2}$, A. V. Eliseev$^{1,2,3}$, I. I. Mokhov$^{1,2}$, S. N. Denisov$^2$, A. V. Timazhev$^2$, G. P. Klimovich$^1$
The results of the analysis of time lags between variations in global surface temperature T and atmospheric CO2 content q, obtained in numerical simulations with the IAP RAS-MSU Earth System model (IAP RAS-MSU ESM) for the period 2020-3000 are presented. In these simulations variations in the energy flux into the climate system associated with natural climatic variability, in particular with a period of about 60 years, and changes in anthropogenic CO2 emissions into the atmosphere were taken into account in accordance with the SSP1-2.6 scenario, continued until 3000 with addition of variations with a period of 50 years, modeling Kondratiev's economic cycles. It is found that changes in T can both lead or lag changes in q, depending on the time interval at which the time lag between T and q is investigated. The results depend on the ratio of the amplitudes of variations in anthropogenic CO2 emissions and variations in the energy flux into the climate system associated with natural variability. The effects that manifest themselves in case of their comparable contribution to the change in T are explained using analytical solutions of a system of equations describing the dynamics of the Earth system in a simplified form. The results obtained indicate that, in general, it is impossible to judge the nature of the cause-and-effect relationship between variables by the time lag between changes in variables without involving physical representations of the nature of their interaction.
Show AbstractEarth's dipole magnetic field: conditions of existence
Earth's dipole magnetic field: conditions of existence
M. Yu. Reshetnyak
Since the formation of the Earth's core and up to the present time, there has been a significant change in the thermal regime on the Earth's surface and in the mantle. At the same time, according to paleomagnetic observations, the dipole magnetic field has not undergone significant changes. Using a parametric model of core and mantle cooling, the paper discusses how this fact agrees with the results of three-dimensional geodynamo modeling. It is shown that several-fold changes in the heat flow at the core-mantle boundary do not cause a change from a dipole magnetic field to a multipole one.
Show AbstractAnomalous Behavior of Gap Intensity in Paired Alkali Metal Nanoparticles with Mesoscopic Boundary Conditions
Anomalous Behavior of Gap Intensity in Paired Alkali Metal Nanoparticles with Mesoscopic Boundary Conditions
Yu. A. Eremin, V. V. Lopushenko
In this paper, we study the influence of a surface quantum effect on the field intensity in a nanometer gap of a pair of gold and sodium nanoparticles. The quantum effect is taken into account based on mesoscopic boundary conditions, including the Feibelman parameters. The simulation was carried out using the discrete source method, which allows calculating near fields with guaranteed accuracy. As a result of the comparative analysis, significant differences in the field intensity in the nanometer gap between gold and sodium particles were discovered. It was found that when taking into account the quantum effect, the field intensity in the gap between sodium particles is higher than in the classical case. This significantly distinguishes them from the gold pair, where taking into account the quantum effect leads to a decrease in intensity.
Show AbstractMethod for Obtaining a Bistatic RCS Diagram of a Body Using Near-Field Data on a Plane or Cylinder with Discrete Sources
Method for Obtaining a Bistatic RCS Diagram of a Body Using Near-Field Data on a Plane or Cylinder with Discrete Sources
N. P. Balabukha$^1$, D. A. Konyaev$^{1,2}$, N. E. Shapkina$^{1,2}$
Today, most measuring systems allow obtaining monostatic radar cross section (RCS), but the ability to obtain bistatic RCS is very important from a practical point of view. Therefore, it is necessary to modernize existing compact ranges in order to measure bistatic RCS. In practice, a near-field scanner is often used for this purpose, with subsequent calculation of the far-field and the corresponding bistatic RCS. In this paper, a method based on the ideas of the discrete source method is proposed for calculating the RCS based on the near-field values when scanning on a plane or part of cylindrical surface. The proposed method is tested by a numerical experiment. A comparison of the results of the presented method with the results obtained by the traditional method of near-field to far-field transform is carried out.
Show AbstractSome Features of the Functional Activity of Multiwall Carbon Nanotubes in Polymer Nanocomposites
Some Features of the Functional Activity of Multiwall Carbon Nanotubes in Polymer Nanocomposites
N. G. Chechenin$^{1,2}$, V. A. Kobzev$^{1,2}$, S. S. Avtorin$^{1,2}$, E. A. Vorobyeva$^1$, A. V. Makunin$^1$
The paper examines the dependence of the functional activity of multiwall carbon nanotubes (MWCNTs) in polymer nanocomposites (PNCs) on the number of layers and the concentration of MWCNTs in the polymer matrix. The analysis shows that the functional activity decreases inversely proportional to the number of MWCNT layers. An increase in the concentration of MWCNTs in the polymer matrix is accompanied, on the one hand, by an increase in the functional activity of MWCNTs due to an increase in the total active surface, and on the other hand, by a decrease due to a decrease in the specific active volume of the polymer matrix. This leads to a peak-shaped dependence of the functional activity of MWCNTs on their concentration in the polymer, which is confirmed by experimental data on the impact resistance of polymer MWCNT composites.
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