bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods and Models for Optimal Managing of District Heating System Accounting Reliability Based on Lagrange Multiplier Method and Markov Random Process
Authors: Stennikov V. A. , Postnikov I. V. , Penkovskii A. V.
Published: April 2024

The main purpose of the study is to determine the optimal condition of the district heating system functioning while minimizing the operating costs for the production and distribution of thermal energy, accounting the expected economic damages from possible heating undersupplies in case of failures of system components. To identification the parameters corresponding to these conditions, a methodological approach is proposed, which consists in the comprehensive calculation of nodal prices for thermal energy and reliability indices for the studied system when different component failures. The determination of nodal prices for thermal energy is based on the Lagrange multiplier method, while the calculation is carried out accounting the different cost of production at heating sources and the distribution of thermal energy flows on the heating network. Within the framework of the studied methodological problem, heating undersupplies to consumers in emergency conditions of the system and the corresponding economic equivalents (damages) are used as reliability indices. Assessment of probabilities of emergency conditions (states) is carried out using models of the markov random process. The general methodological basis for modeling thermal-hydraulic conditions in the system, including emergency ones, are the models of the theory of hydraulic circuits. The developed methods and models, along with the main formulated problem of optimal managing, allow identifying “bottlenecks” in the studied system, corresponding to the maximum economic damages from heating undersupplies to consumers based on obtained reliability indices. A computational experiment was carried out using the proposed methodology. The results are analyzed, their graphical interpretations are presented, and directions for further research are formulated.
Method for Aligning Instrument and Related Coordinate Systems on Aircraft
Authors: Lisitsyn V. M. , Obrosov K. V. , Sebryakov G. G.
Published: April 2024

A method is proposed for coordinating the instrumental coordinate systems of different posts of the optical-electronic system of aircraft with each other and with the inertial navigation system. The method does not require preflight preparation and is based on processing video information streams generated by thermal imaging and television channels of the optoelectronic system and using information from inertial navigational and radar systems when performing special maneuvers. Theoretical analysis of the accuracy and modeling showed the potential benefits of the proposed method.
Optimal Control of Systems with Distributed Parameters Under the Interval Uncertainty of an Object’s Characteristics
Authors: Pleshivtseva Yu. E. , Rapoport E. Ya.
Published: April 2024

A constructive method is proposed for solving a linear-quadratic problem of the robust optimization of spatiotemporal control actions in systems with distributed parabolic parameters under conditions of interval uncertainty of the time-invariant parametric characteristics of an object. In accordance with the control strategy according to the principle of the best guaranteed result, the assessment of achievable target sets of the controlled system is carried out according to the accuracy of uniform approximation to the required final state on an extended set of arguments, which includes, in addition to spatial variables, the entire admissible set of uncertain factors. The developed approach is based on the previously developed alternance method for constructing parameterizable program control algorithms, which extends the results of the theory of nonlinear Chebyshev approximations to a wide range of optimization problems and uses the fundamental laws of the subject area. It is shown that the proposed equations of optimal controllers, which are reduced to linear feedback laws on the measured state of the object with nonstationary transmission coefficients, lead to achievable values of the optimality criteria that do not exceed their upper bounds under the considered uncertainty conditions
Control of a Mobile Robotic System for the Maintenance of Vertical Surfaces
Authors: Alhaddad M. , Chashchukhin V. G.
Published: April 2024

A robotic complex consisting of a transport-handling platform and a climbing robot installed on it is considered. The platform is designed to move the robot on a horizontal surface and place it on a vertical surface. The practical implementation of the platform control algorithm is described, which makes it possible to automate the process of placing the robot on a vertical surface.
Designing an ACS by Applying Galvanic Coatings Based on Solving the Optimization Problem
Authors: Bannikov A. A. , Litovka Yu. V. , Nesterov V. A. , Sypalo K. I.
Published: April 2024

An automated control system for the technological process of applying galvanic coatings to a variety of cathode parts of various shapes and sizes is considered based on solving the problem of finding the optimal arrangement of the parts in a galvanic bath to obtain coatings with the minimum value of criterion R—the ratio of the number of rejected parts Nreject to the total number of parts N placed on the suspension device. To solve the problem, a calculation-logical system is developed that uses the exhaustive enumeration method, the Gomory algorithm modified by the authors, and the branch-and-bound method. When solving the problem, the Gomory algorithm is found to be the best algorithm among the three methods in terms of performance. A two-level control system for the galvanic process in a bath with a suspension device is developed.
Problem of Controlling a Steam Generator under Uncertainty with Constraints on the Phase Variables and Controls
Authors: Gulyukina S. I. , Utkin V. A.
Published: April 2024

The problem of controlling a steam generator is considered, taking into account restrictions on the phase variables and control under the effect of external uncontrolled disturbances. To synthesize the control law, a block approach is used with the formation of linear local relationships with saturation, which makes it possible to take into account restrictions on phase variables and control when choosing feedback parameters. Under conditions of incomplete information about the state vector and under the effect of external disturbances, an observer of states and disturbances is synthesized, which makes it possible to obtain estimates of unknown signals with the given accuracy. The efficiency of the proposed algorithms is confirmed by the results of numerical simulation.
Analytical Quasi-Optimal Algorithm for the Programmed Control of the Angular Motion of a Spacecraft
Authors: Molodenkov A. V. , Sapunkov Ya. G.
Published: April 2024

The problem of the optimal program control of the angular motion of a spacecraft (SC) as a rigid body with a quadratic functional of the energy spent on the maneuver of the SC and a fixed time of the transition process is investigated. The dynamic configuration of the SC and the boundary conditions are arbitrary and the control vector function is not limited. In the Poinsot concept, using the Pontryagin maximum principle, a quasi-optimal analytical solution of the problem is obtained, which is developed into an algorithm. Confirming numerical examples are given, showing the proximity of the quasi-optimal solution to the optimal solution of the problem.
Three-Dimensional Reachability Set For a Dubins Car: Reduction of the General Case of Rotation Constraints to the Canonical Case
Authors: Patsko V. S. , Fedotov A. A.
Published: April 2024

In mathematical control theory, a Dubins car is a nonlinear motion model described by differential relations, in which the scalar control determines the instantaneous angular rate of rotation. The value of the linear velocity is assumed to be constant. The phase vector of the system is three-dimensional. It includes two coordinates of the geometric position and one coordinate having the meaning of the angle of inclination of the velocity vector. This model is popular and is used in various control tasks related to the motion of an aircraft in a horizontal plane, with a simplified description of the motion of a car, small surface and underwater vehicles, etc. Scalar control can be constrained either by a symmetric constraint (when the minimum rotation radii to the left and right are the same) or asymmetric constraint (when rotation is possible in both directions, but the minimum rotation radii are not the same). Usually, problems with symmetric and asymmetric constraints are considered separately. It is shown that when constructing the reachability set at the moment, the case of an asymmetric constraint can be reduced to a symmetric case.
Problem of the Boundary Control of Oscillations of a Sample of a Layered Two-Phase Composite Material
Authors: Egorova A. A. , Shamaev A. S.
Published: April 2024

We consider the problem of the boundary control of one-dimensional oscillations of an effective (averaged) medium corresponding to a two-phase medium consisting of periodically alternating layers of elastic and viscoelastic materials with long-term memory or various viscoelastic materials with Kelvin–Voigt friction and long-term memory. The averaged model is described by a boundary value problem for an integrodifferential equation. It is shown that for this model, it is impossible to bring oscillations to a state of rest in finite time (in contrast to the equation of string oscillations) by a force acting at one end of the band. A hypothesis is formulated on the possibility of bringing the specified object to a state of rest with the help of force effects distributed along the entire length of the object.
Machine Learning for Software Technical Debt Detection
Authors: Kachanov V. V. , Markov S. I. , Tsurkov V. I.
Published: April 2024

The problem of technical debt arises when part of software source code is upgrading not directly, but is fixed in the second place as outdated. Three corresponding models are presented. Machine learning is used to find code smells. The effectiveness of the approach for specific data is established and the prospect of expanding to a greater number of different cases is outlined.
Game-Theoretic Specificity of a Competitive Allocation of the Frequency Spectrum
Authors: Kaplan V. S. , Novikova N. M. , Pospelova I. I.
Published: April 2024

We consider the problem of developing and optimizing the rules of the spectrum auction. One-sided sealed-bid spectrum auctions are studied. Two types of pricing are compared theoretically: the first-price and the second-price. А game model of the auction with free riders is constructed. A free rider uses frequencies purchased by another such participant for free. All Nash equilibria of the obtained games are found and represented in an analytical form. The significant difference between games with all free riders and games with at least one ordinary player is shown. It is proved that when players eliminate their dominated strategies, the resulting auction price of the lot is determined by its value for ordinary players. In the case when all players are free riders, the price is equal to the minimal bid price. The influence of the information the participants have about their partners’ values of a lot on the outcome of the game is discussed. The theoretically obtained properties are in agreement with the results of the experiments presented for spectrum auctions in the scientific literature.
Model Estimate of the Acidity of Atmospheric Precipitation Acidity Due to Anthropogenic Sulfur Compounds in the 20th Century
Authors: Gizatullin R. D. , Eliseev A. V.
Published: April 2024

An analysis of the acidity of precipitation is carried out by using the ChAP-1.0 (Chemistry and Aerosol Processes) atmospheric sulfur cycle scheme developed for Earth System Models of Intermediate Complexity (EMICs)These calculations are forced by monthly mean anthropogenic emissions of sulfur dioxide to the atmosphere in 1850–2000 adapted from the CMIP5 (Coupled Models Intercomparison Project, phase 5) database and by long-term means (taking into account annual variations) of meteorological variables adapted from the ERA-Interim reanalysis for 1979–2015. It was revealed that significant acidity of precipitation (minimum pH of hydrometeors) is typical for regions with high anthropogenic loading of sulfur compounds in atmosphere – Europe, southeast Asia, east North America, southern Africa, and western South America. In these regions in the last decades of the 20th century, typical precipitation values of pH amount from 2.5 to 3.5, which agrees well with the available measurements. The maximum acidity of precipitation (the minimum pH of hydrometeors, which is close to 2) due to anthropogenic sulfur are noted in the eastern Mediterranean region. Atmospheric transport leads to regions with pH 3.5 covering almost all of Eurasia in the last decades of the 20th century. The influence of this transport is also noticeable in other midlatitudinal regions – south of North America and western South America. In general, the ChAP scheme can be used in EMICs, but after a refinement to account for the effect of various types of precipitation on the wet deposition of sulfur compounds from the atmosphere and the effects of orography on the transport of chemical species in the atmosphere
Estimation of Carbon Balance in Steppe Ecosystems of Russia
Authors: Golubyatnikov L. L. , Kurganova I. N. , Lopes de Gerenyu V. O.
Published: April 2024

Steppe ecosystems, occupying about 8% of the terrestrial area, are an essential element of the global carbon cycle in the atmosphere–vegetation–soil system. Based on the geoinformation-analytical method, the database of empirically measured values of the net primary production and the climate-driven regression model that makes it possible to estimate the intensity of carbon dioxide flux from soils into the atmosphere, the carbon (C–СО2) balance of natural steppe ecosystems in Russia was estimated. Natural steppes in Russia serve as a significant sink of carbon dioxide from the atmosphere. The intensity of this carbon flux can be estimated as 231 ± 202 gC/m2 per year. The annual accumulation of carbon dioxide in the natural steppe ecosystems of Russia is evaluated as 111 ± 97 MtC. According to the obtained estimates, the steppe ecosystems under study provide from 8 to 19% of the atmospheric carbon sink to the terrestrial ecosystems of Russia.
Approximation of Small Amplitude Waves Short in Vertical in the Atmosphere Taking Into Account the Average Wind
Authors: Kshevetskii S. Р. , Kurdyaeva Y. А. , Gavrilov N. М.
Published: April 2024

Using the method of different scales, formulas for the hydrodynamic fields of acoustic-gravity waves (AGWs) with vertical wavelengths small compared to the scales of changes in the background temperature and wind fields are derived. These formulas are equivalent to the conventional WKB approximation, but explicitly include the vertical gradients of the background fields. The conditions for the applicability of the obtained formulas for describing the propagation of AGWs from the troposphere to the thermosphere are formulated and analyzed. The absence of singular points (critical levels) in the equations for wave modes in the analyzed height range is one of the conditions for the applicability of approximate formulas. For the wind from the empirical HWM model, singular points are often located below 200 km and are typical for internal gravity waves (IGWs), with lengths of the order of 10 km. As the wavelength increases, the number of singular points decreases. For IGWs with scales on the order of 300 km or more, there are usually no singular points. It is shown that IGWs with periods of less than 20 min propagating upward from tropospheric heights usually have one turning point in the altitude range from 100 to 130 km. The obtained formulas are useful, in particular, for parametrization of AGW effects in numerical models of atmospheric dynamics and energy.
On the Types of Instability of a Geostrophic Current with a Vertical Parabolic Profile of Velocity
Authors: Kuzmina N. P. , Skorokhodov S. L. , Zhurbas N. V. , Lyzhkov D. A.
Published: April 2024

An analysis is made of unstable perturbations of a geostrophic current of finite transverse scale with a parabolic vertical velocity profile of a general form (with linear and constant velocity shear) in vertically limited layer. The model is based on the potential vortex equation in the quasi-geostrophic approximation, taking into account the vertical diffusion of momentum and mass. The equation and boundary conditions were reduced to a spectral eigenvalue problem of the Orr-Sommerfeld type. To search for eigenfunctions and eigenvalues, a high-precision analytic-numerical method was used. Particular attention was paid to the study of unstable perturbations with a phase velocity exceeding the maximum flow velocity. Such instability should be distinguished from baroclinic instability and critical layer instability. It is found that the indicated instability can develop in ocean currents when the problem parameters vary in a wide range of values. It is obtained also that with an increase in the Prandtl number, the phase velocity of such disturbances increases and can significantly exceed the maximum flow velocity. However, the occurrence of such unstable perturbations is possible only in the cases when the maximum flow velocity is located in the inner region of the layer (but not necessarily in its center). It has also been found that narrow currents (the transverse scale is equal to or smaller than the Rossby radius) with a parabolic vertical profile can be unstable. The most unstable perturbations have approximately equal scales along and across the flow, that is, they are circular perturbations. A discussion of various types of geostrophic current instability with a parabolic vertical velocity profile as applied to the ocean is presented.
Comparison of СO2 Content in the Atmosphere of St. Petersburg According to Numerical Modelling and Observations
Authors: Nerobelov G. M. , Timofeyev Yu. M. , Smyshlyaev S. P. , Foka S. Ch. , Imhasin H. H.
Published: April 2024

Due to the increase in CO2 content in the Earth’s atmosphere, which is highly dependent on anthropogenic emissions of CO2, quality of emission estimation should be improved. Advanced experiment-based methods of the CO2 anthropogenic emission estimation are built on solution of an inverse problem using highly-accurate measurements of CO2 content and numerical models of transport and chemistry in the atmosphere. The accuracy of such models greatly determines errors of the emission estimations. In a current study temporal variations of column-average CO2 content in an atmospheric layer from surface to the height of ~70–75 km (XCO2) in the Russian megapolis of St. Petersburg during Jan 2019–Mar 2020 simulated by WRF-Chem model and measured by IR Fourier-transform spectrometer Bruker EM27/SUN are compared. The research has demonstrated that the WRF-Chem model simulates well the observed temporal variation of XCO2 in the area of St. Petersburg (correlation coefficient of ~0.95). However, using CarbonTracker v2022-1 data as chemical boundary conditions, the model overestimates XCO2 relative to the observations significantly during almost the whole period of investigation – systematic difference and standard deviation of the difference are 4.2 and 1.9 ppm (1 and 0.5%). A correction of the chemical boundary conditions which is based on analysis of a relation between near-surface wind direction and XCO2 variation notably decreases the systematic difference between the modelled and observed data (almost by a factor of 2). The XCO2 variation by the observations and modelling with uncorrected chemical boundary conditions are in a better agreement during vegetation season. Probably this is related to the compensation of the systematic difference by inaccuracies in estimated biogenic contribution. Hence, the reason of the still existing mean difference between the modelled and observed data can be inaccuracies in setting chemical boundary conditions for upper troposphere and in estimating how biosphere influences CO2 content.
Ground-Based FTIR-Measurements of the Atmospheric Nitric Acid at the NDACC Site of St. Petersburg
Authors: Virolainen Ya. A. , Timofeyev Yu. M. , Polyakov A. V. , Poberovsky A. V.
Published: April 2024

Atmospheric nitric acid (HNO3) has a significant impact on the formation of the ozone layer; therefore, its content is regularly monitored using various local and remote-sensing methods. We used ground-based measurements of solar IR spectra with a Bruker 125HR Fourier spectrometer to derive information on the HNO3 content at the St.Petersburg observational NDACC site in Peterhof. The HNO3 time series obtained showed a pronounced seasonal cycle with a maximum in winter and early spring and a minimum in summer and early autumn. The averaged seasonal variations in nitric acid varied from –30 to +60% for the 0–15 km layer, from –25 to +25% for the 15–50 km layer, and from –25 to +30% for total columns. For 2009–2022 measurement period, no statistically significant trend was found in the time series considered. Comparison of HNO3 stratospheric columns with independent satellite measurements by the MLS and ACE-FTS instruments showed their qualitative and quantitative agreement; the correlation coefficient between ground-based and satellite measurements totals 0.88–0.93. Time series on the vertical structure of the atmospheric nitric acid measured at the St.Petersburg site can be used both to analyze the state of the ozonosphere and to validate satellite measurements and refine the parameters of atmospheric models.
Projected Changes in the Snow Cover Extent in the 21st Century in Eurasia According to Simulations with the Ensemble of Climate Models CMIP6
Authors: Parfenova M. R. , Arzhanov M. M. , Mokhov I. I.
Published: April 2024

The analysis of changes in the snow cover extent S in Eurasia was performed using the results of simulations with the ensemble of global climate models of the international project CMIP6 under the scenario of anthropogenic impacts SSP2-4.5 for the 21st century. Features of S variability in relation to changes in surface air temperature T in different seasons are revealed by comparison of ensemble model calculations for the “historical” scenario to CDR satellite data against the background of a general decrease in the snow cover extent in Eurasia during the contemporary warming. It is noted that the multimodel ensemble mean estimates of the sensitivity parameter dS/dT for the transitional seasons in spring and autumn can be significantly lower in absolute values than those for the individual models and those derived from the satellite data. Comparison of model estimates with satellite observation data showed that the models generally reproduce the observed variations in the snow cover area in Eurasia, while variations in the area may be underestimated for individual models. According to ensemble model calculations, the rate of snow cover reduction in Eurasia in the second half of the XXI century decreases compared to the first half of the XXI century for all seasons. At the same time, the maximum values of snow cover extent reduction rate in Eurasia are inherent in transitional seasons – autumn and spring.
Changes in the Oxygen Content in Urban Air under the Influence of Natural and Anthropogenic Factors
Authors: Ginzburg A. S. , Vinogradova A. A. , Lezina E. A. , Pomelova M. A.
Published: April 2024

The article analyzes the results of measuring the oxygen content in Moscow in 2017–2021 at three automatic stations for monitoring atmospheric pollution of the “Mosecomonitoring”. Seasonal variations of oxygen content in the city are considered, the issues of compliance of the obtained values with the scale of comfort level for human breathing developed by medical specialists are discussed, measurement data are compared with the results of calculating the oxygen concentration in the air by the magnitude of meteorological parameters. According to the measurements, diurnal variations of the O2 content in the surface urban air, more pronounced in the warm season, were revealed. The minimum O2 content is observed in summer in the early morning hours. The main natural and anthropogenic processes that determine the variability of oxygen content in the surface air of a megalopolis at different time scales are discussed.
ON TEMPORAL VARIATIONS IN THE GRANULOMETRIC CHARACTERISTICS OF BINARY MIXED MICROPOWDERS TREATED IN A PLANETARY-TYPE BALL MILL
Authors: SAVENKO V. I.
Published: April 2024

Integral and differential particle size distribution functions have been experimentally determined for two-component mixed micropowders, which contain stoichiometric amounts of polycrystalline aluminum, nickel, and titanium, as well as amorphous boron, and have been mechanically treated in a planetary-type ball mill under different time conditions of the process. The influence of the duration of treatment of the above mixtures on the mathematical parameters of the found distribution functions has been analyzed. It has been shown that, in all considered cases, these functions can be represented in a lognormal form. The most informative statistical characteristics (moments) of these functions have been determined. The dependences of these characteristics on the duration of the mechanical treatment of the mixtures have been revealed. Within the framework of an approximation based on the use of generalized dynamic-stochastic Langevin-type equations, a kinetic model has been proposed for the process of mechanical treatment of metallic and non-metallic mixed micropowders in planetary-type mills. The model makes it possible to describe, as a first approximation, the temporal evolution of the fractional composition of the mixtures during their machining, as well as to record temporal variations of the main statistical characteristics of the corresponding distribution functions in this process.
SOME FEATURES OF CAPILLARY WAVE ENERGY CONVERSION ON LIQUID SURFACE IN THE PRESENCE OF DYNAMIC SURFACE TENSION
Authors: GRIGORIEV A. I. , KOLBNEVA N. YU. , SHIRYAEVA S. O.
Published: April 2024

The effect of dynamic surface tension on capillary oscillations of a droplet is studied in the theoretical asymptotic calculations of the first order of smallness with respect to the dimensionless amplitude of oscillations of charged droplets of a polar liquid. The calculations are carried out within the framework of a model of an ideal incompressible electrically conducting liquid. It has been shown that allowance for the effect of dynamic surface tension increases the order of the dispersion equation, which acquires one more damping root relevant to the destruction of the near-surface electrical double layer (disordering of molecules in the near-surface layer). What is interesting about the revealed damping is that it takes place in an ideal liquid, while the characteristic damping time coincides with that measured experimentally. Free energy transformations occur between mechanical, thermal, electromagnetic, and mechanical again forms of energy, with all of the transformations being caused by the effect of the dynamic surface tension. It has been shown that the dynamic surface tension has a weak effect on the low-frequency oscillations of the droplets, while it essentially affects the high-frequency oscillations causing their rapid damping.
NATURAL ELECTRORHEOLOGICAL FLUIDS BASED ON CELLULOSE PARTICLES IN OLIVE OIL: THE FILLER SIZE EFFECT
Authors: KUZNETSOV N. M. , KOVALEVA V. V. , VDOVICHENKO A. YU. , CHVALUN S. N.
Published: April 2024

The rheological behavior of 1 wt % suspensions of micro- and nanocellulose in olive oil is studied at various electric field strengths up to 7 kV/mm. The particle morphology is evaluated by optical and electron microscopy. Under an electric field, a contrast transition from a simply viscous behavior of fluids to a visco-elastic one is observed, while the suspensions show yield stress and storage modulus. A higher electrorheological response of suspensions filled with nanocellulose compared to microcellulose has been established. Based on the dependences of the static yield stress on the electric field strength, an analysis of the mechanism of the electrorheological effect has been provided. The use of completely natural components has shown promise of developing novel, environmentally friendly “smart” materials.
CHARACTERISTICS OF AN ELECTRICAL DOUBLE LAYER OF BULK NANOBUBLES IN WATER
Authors: LEVIN YU. K.
Published: April 2024

When analyzing the characteristics of the electrical double layer of bulk nanobubbles in water, the conditions for the existence of their Stern layer are found. It is taken into account that the surface of the bubble is surrounded by a thin layer of “bound” water, on top of which the counterions of the Stern layer are placed. The stability of this layer depends on two factors: the minimization of the Gibbs energy of counterions in the diffuse layer and the energy of their thermal motion, which is capable of pulling the counterion out of the Stern layer and returning it to the region of the diffuse layer. The charge of nanobubbles has been determined, which corresponds to both the minimum Gibbs energy of counterions and the thermal stability of the Stern layer. The dependence of the critical radius of the stable Stern layer on the concentration of dissolved salts is determined.
STABILITY OF SOME SILICONE LUBRICATING INTERLAYERS IN LIQUID-INFUSED COATINGS
Authors: EMELYANENKO K. A. , FEOKTISTOVA L. S. , LUNEV I. V. , GALIULLIN A. A. , MALYSHKINA I. A. , KRASOVSKIY V. G.
Published: April 2024

One of the most actively developing research areas in materials science relevant to polyfunctional coatings is the creation of slippery liquid-infused porous surfaces (SLIPS) based on porous hydrophobic or hydrophilic materials filled with low-volatility viscous liquids (lubricants). In the present work, we have investigated the possibility of using two organosilicon liquids of different polarities, bis(trifluoromethylsulfonyl)imide dicationic ionic liquid and silicone oil, as lubricants for fabricating slippery coatings that reduce the adhesion of solid and liquid aqueous precipitations to aluminium oxide substrates. To calculate the stability of the films of such lubricants, we have employed the theory of van der Waals forces to study the refractive index dispersions and the dielectric properties of the liquids in the region of microwave relaxation. On the basis of experimentally obtained data, the dielectric permittivity spectra have been calculated as functions of imaginary frequency for the entire spectral range, as well as the contribution of the van der Waals forces to the stability of the disjoining pressure isotherms of the lubricant films on the hydrophobic and hydrophilic aluminium oxide substrates. The disjoining pressure isotherms obtained in this work have indicated that the ionic liquid used to prepare slippery coatings is a more durable lubricant than silicone oil, because its films retain their stability when the vapor phase is replaced by an aqueous medium over a wider range of thickness.
NOBLE METAL NANOPARTICLES IN BIOMEDICAL THERMOPLASMONICS
Authors: DEMENT’EVA O. V. , KARTSEVA M. E.
Published: April 2024

The unique properties of metal nanoparticles (NPs) resulting from their localized surface plasmon resonance have led to the emergence and rapid development of promising scientific areas. One of these area is thermoplasmonics, which is based on the ability of such NPs to effectively transform optical radiation into heat. We discuss the optical properties of noble metal NPs, the main approaches to their synthesis, as well as the latest advances of thermoplasmonics in the field of biomedicine. The focus of this review is on photothermal diagnostics and therapy (theranostics) of various diseases. Note that, in addition to theranostics of tumors, the prospects for the use of plasmonic NPs in cardiology, ophthalmology, the fight against bacterial and viral infections, and other biomedical fields have been analyzed.
Enzyme-Like Activity of Cerium Dioxide Colloidal Solutions Stabilized with L-Malic Acid
Authors: Filippova A. D. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

For the first time, stable aqueous colloidal solutions of cerium dioxide stabilized with L-malic acid have been obtained at ligand : CeO2 molar ratios of 0.2, 0.5, 1.0, and 2.0. Using dynamic light scattering, it has been shown that CeO2 sols are characterized by a narrow monomodal size distribution of aggregates, and the sols remain to be aggregatively stable in a Tris-HCl buffer solution. According to the chemiluminescence analysis of the enzyme-like activity of cerium dioxide sols with respect to hydrogen peroxide, the surface modification of the cerium dioxide particles with malic acid increases the enzyme-like activity of СеО2 up to 4.5 times.
Colloidal Objects in Biomedicine: Modern Trends and Prospects
Authors: Kuznetsova E. V. , KUZNETSOV N. M.
Published: April 2024

This review presents historical retrospective on the development of biomedicine as a science and indicates the role of colloidal objects, as well as contains the summary of the reviews and research articles included in the special issue.
Experimental Study of Evaporation of Nanofluid Droplets on Substrates under Solar Radiation
Authors: Tran K. T. , Dmitriev A. S. , Makarov P. G. , Mikhailova I. A.
Published: April 2024

This work is devoted to the experimental study of evaporating droplets of titania-, silica-, and diamond-based nanofluids on a substrate under solar radiation. The influence of various factors, including the type of a material, concentration of nanocomponents, irradiation direction, droplet volume, and substrate material, on the droplet evaporation has been investigated. As a result, the critical concentrations of nanoparticles, at which the evaporation rate reaches a stable level, have been determined for droplets of the studied nanofluids. The regimes and stages of the droplet evaporation process have been analyzed for the cases of the subcritical and critical nanoparticle concentrations. The efficiency of droplet evaporation under solar radiation has been shown to strongly depend on radiation direction. The effects of droplet volume and substrate material on the evaporation rate have been studied. In addition to the evaporation efficiency, the morphology of the structures deposited from the droplets has been analyzed. It has been shown that these structures depend on the concentration and material of nanoparticles, as well as on the regime of droplet evaporation. The results of this study enable one to gain a deeper insight into the behavior of the droplets during evaporation under irradiation especially in the IR region and confirm the promise of application of nanofluids in the solar thermal energy systems.
On Residual Modulation of Galactic Cosmic Rays in the Heliosphere
Authors: Yanke V. G. , Belov A. V. , Gushchina R. T. , Kobelev P. G. , Trefilova L. A.
Published: April 2024

The residual modulation of galactic cosmic rays and its energy dependence have been investigated using data from three types of ground-based detectors and from PAMELA, AMS-02, Voyager 1, and Voyager 2 data. Quantitative estimates of the residual modulation in the range of rigidities of 4–41 GV were obtained. It was shown that the residual modulation is approximately the same in magnitude as the modulation due to the solar activity cycle that allows us to draw some conclusions about the modulation processes in the heliosphere. The energy spectrum of the residual modulation was obtained. A comparison was made with the results of other authors up to the Maunder epoch.
Estimation of the Space–Time Spectrum of Waves Based on Circular Measuring Gratings
Authors: Belokonov I. V. , Zhuravlev V. M. , Morozov V. M.
Published: April 2024

In this paper, a method for estimating the spectra of wave processes based on a special type of measuring lattices, which are a set of rotating and static sensors, called “circular,” is developed. A method for correcting spectra estimated on the basis of discrete digital series obtained from circular lattice sensors is described. Spectra estimates are based on the multidimensional maximum entropy method. The data of test calculations for several types of circular lattices are presented as applied to wave processes in the form of harmonics distorted by white noise. The effectiveness of the proposed method for correcting spectra is shown. The general principles of using circular lattices for estimating the spectra of wave processes with the help of sensors located on rotating satellites are outlined. The possibility of using this approach for estimating the spectra of wave processes using sensors installed on micro- and nanosatellites is discussed.
The Radiation Resistance of Microelectronic Devices under the Combined Influence of Destabilizing Factors of Space at the Design Stage
Authors: Didyk P. I. , Zhukov A. A.
Published: April 2024

An estimation of the joint action of destabilizing factors of space on typical microelectronic components in the design of onboard spacecraft equipment is presented, and an estimation of the characteristics of microelectronic components under radiation exposure is shown.
Coronal Propagation of Solar Protons during and after Their Stochastic Acceleration
Authors: Grigorieva I. Yu. , Struminsky A. B. , Logachev Yu. I. , Sadovskii A. M.
Published: April 2024

Solar protons in eruptive flares are stochastically accelerated in a wide spatial angle, and then they are effectively kept behind the expanding coronal mass ejection (CME) front, which can either bring protons to the magnetic-field line going to a remote observer or carry them away. We consider 13 solar proton events of cycle 24 in which protons with energy E 100 MeV were recorded and were accompanied by the detection of solar hard X-ray (HXR) radiation with E 100 keV by an ACS SPI detector and γ-radiation with E 100 MeV by the FermiLAT telescope with a source in the western hemisphere of the Sun. The first arrival of solar protons into the Earth’s orbit was determined in each event by a significant “proton” excess over the ACS SPI background during or after the HXR burst. All events were considered relative to our chosen zero time (0 min) of parent flares. The “early” arrival of protons to the Earth’s orbit (+20 min), which was observed in four events, corresponds to the “fast” acceleration of electrons (10 MeV/s). The “late” arrival of protons (+20 min) corresponds to the “slow” acceleration of electrons (1 MeV/s) and was observed in six events. In three events, a “delayed” arrival of protons (+30 min) was observed, when the CME propagation hindered the magnetic connection of the source with the observer. The direction of CME propagation is characterized in the catalog (SOHO LASCO CME Catalog) by the position angle (PA). The observed PA systematizes the times of the first arrival of protons and the growth rate of their intensity. The PA parameter should be taken into account in the analysis of proton events.
The Relationship of Magnetospheric Parameters with Cosmic-Ray Cutoff Rigidities Depending on Latitude
Authors: Danilova O. A. , Ptitsyna N. G. , Tyasto M. I. , Sdobnov V. E.
Published: April 2024

We have studied the features of the latitudinal behavior of geomagnetic thresholds of cosmic rays R, as well as their sensitivity to the interplanetary medium and magnetospheric parameters during three phases of the magnetic storm on September 7–8, 2017, in the initial, main, and recovery phases. For this purpose, values of R were calculated in two different ways—by the method of spectrographic global survey (Rsgs) and by the method of tracing the trajectories of cosmic-ray (CR) particles in the model magnetic field (Ref). The maximum lowering of thresholds is observed at the storm maximum (Dst = –142 nT), reaching the values of ΔRsgs = –0.52 GV and ΔRef = –0.66 GV. The curve of ΔRsgs variations, depending on the observation station (latitude) cutoff rigidity, assumes a classical form with a maximum dropping the thresholds at midlatitudinal stations. ΔR correlates most strongly with the Dst index, which indicates that the ring current plays a main part in the dependence of variations of CR cutoff rigidities. The significant influence of solar-wind velocity V and interplanetary magnetic field (IMF) parameters on ΔRsgs and ΔRef is also seen. In the main phase, ΔRef depends on B and Bz of the IMF, and ΔRsgs depends on B and By. For ΔRsgs, the correlation with electromagnetic parameters varies, depending on the observation station, in a regular manner. There is no such tendency for ΔRef.
Exploration of the Moon by Automatic Spacecraft
Authors: Marov M. Ya.
Published: April 2024

Problems of the study and exploration of the Moon, which is of paramount interest for cosmogony, planetology, and Earth sciences in the context of a comprehensive study of the Solar System, are discussed. A historical review of lunar exploration is given, a fundamental contribution to which was made by the Soviet lunar program, carried out with the help of automatic spacecraft in the first decades of the space age. The review is timed to coincide with the revival of lunar exploration within the framework of the Russian national space program. The current state of knowledge about the Moon is considered—first of all, key questions about its origin and early evolution. This is of paramount importance for the reconstruction of the main processes of formation of the entire family of bodies in the Solar System, including the early history of the Earth, as well as the reasons for the various evolutionary paths of the Earth and the terrestrial planets. At the present stage, exploration of the Moon as a strategic foothold on the path of human space exploration and the creation of elements of the future lunar infrastructure using local natural resources in the potentially most demanded polar regions are urgent. The South Pole is the target of the Russian Luna-25 and Luna-27 missions, with an extensive science program that aims to start a multipurpose program with the efficient use of new-generation robotics. This program predates Russian plans for manned flights to the Moon.
Energy Spectra of 3He, 4He, C, O, and Fe Suprathermal Ions per 1 AU in Particle Flows from Coronal Holes in the 23rd and 24th Solar Cycles
Authors: Zeldovich M. A. , Logachev Yu. I.
Published: April 2024

The energy spectra of ions 3He, 4He, C, O and Fe with energies of 0.04–2 MeV/nucleon were studied at 1 AU in solar-wind streams from near-equatorial coronal holes during the decline of solar activity in cycle 23 according to the information of the ULEIS, SWICS, and SWEPAM instruments installed onboard the ACE spacecraft. The results of this work show that suprathermal ions from coronal holes are Maxwellian solar-wind ions accelerated on the Sun and/or in interplanetary space and form a high-energy contribution to solar-wind ions (a suprathermal “tail” in the energy distribution of solar-wind ions). The energy spectra of accelerated “tail” ions have different dependences on energy, which indicates different mechanisms of their acceleration. The relationship between the intensity of suprathermal ions and the speed of the solar wind indicates the effectiveness of the acceleration of Maxwellian solar-wind ions.
Preliminary Results of Data Processing of the TRITEL Dosimeter as Part of the Matryoshka-R Space Experiment onboard the Russian Segment of the International Space Station
Authors: Lishnevskii A. E. , Shurshakov V. A. , Kartashov D. A.
Published: April 2024

Preliminary results of processing data from the TRITEL dosimetric equipment, which consists of one interface unit and three units of mutually orthogonal telescopes of silicon detectors operating in the coincidence mode (with the possibility of obtaining data also from a single mode of operation), are presented. The TRITEL dosimeter was designed to study the temporal dynamics of dose loads and the anisotropy of charged particle fluxes at various points of the Service Module (SM) of the Russian segment of the International Space Station (RS ISS) with the additional possibility of measurements in other modules of the RS ISS. As part of the Matryoshka-R space experiment (SE) on the RS ISS the TRITEL dosimeter was in operation from mid-October 2017 to mid-October 2020. The article presents a description of the methodology for processing dosimetric data of the TRITEL equipment and preliminary results of processing data obtained in the period from June to October 2020.
Predicting the Parameters of the Orientation of the Earth in Problems of Navigation Taking into Account the Phenomenon of the Development of Irregularity in the Earth’s Rotation
Authors: Krasilshchikov M. N. , Kruzhkov D. M. , Martynov E. A.
Published: April 2024

This article discusses the application of a previously proposed [1] methodology for predicting the Earth’s orientation parameters (EOPs) that provides high accuracy as a result of optimizing a special procedure of processing historical data using the least-mean-squares method. The results of investigating the accuracy characteristics of the obtained EOP estimations are presented in relation with a predictive task in the interval from 2019 to 2022, when, for the first time in the history of observing the Earth’s daily rotation, a change was recorded in the difference trend between Universal Time and Coordinated Universal Time was recorded, caused by the length of day decreasing. The influence of the length of the day trend changing and related problems on the accuracy of EOP prediction in various navigation tasks using classical polynomials describing EOP evolution is discussed. A comparative analysis of the EOP prediction made by the International Earth Rotation and Reference Systems Service for a similar time period is carried out.
Time Series of Space Observations: Analysis of Local Meteorological and Solar Series
Authors: Kurbasova G. S. , Volvach A. E. , Volvach L. N.
Published: April 2024

A range of issues related to the results of the analysis of some meteorological and solar series of satellite observations in the Kara-Dag area (Crimea) is considered. A qualitative and quantitative picture of changes in the total insolation falling on the Earth’s surface, air temperature at a height of 2 m, and the Earth’s surface temperature in Kara-Dag over the past 38 years is presented. A numerical model has been constructed that makes it possible to predict the most powerful fluctuation with a period of 1 year in the analyzed data. The following methods were used in the work: the method of wavelet analysis, statistical methods for extracting Gaussian and non-Gaussian noise, an iterative method for constructing and estimating the accuracy of model approximations. Coherent variations in the analyzed and some global geodynamic and solar time series were established using two-channel autoregressive analysis. A qualitative characteristic of the process of changing the main variations in the analyzed time series was obtained using the analysis of phase trajectories on the Poincaré plane.