bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Organisational Ambidexterity a Good Booster to Supply Chain Flexibility in the Textile and Apparel Industry in Sri Lanka?
Authors: Seimon A.T.M. , Endagamage D.M.
Published: April 2024

The environment does not remain stable forever because change is inevitable. The frequency and speed of change however varies from industry-to-industry, business-to business. Thereby, the manner by which a firms’ supply chain adapts to these environment dynamics demand greater attention. Building on the relationship between manufacturing strategy and the environment, the purpose of this paper is to analyse the direct impact of environmental dynamism on supply chain flexibility, and the indirect impact of achieving supply chain flexibility required by the environment through organisational ambidexterity in the Sri Lankan textile and apparel industry which is an industry under increased pressure to be more flexible and the highest export revenue contributor to the economy. A positivism paradigm provided the foundation for this explanatory research. A cross-sectional survey method was used to collect the primary data from operations or supply chain managers across firms in the Sri Lankan textile and apparel industry. Eighty-seven responses were received and analysed using the SmartPLS software. As a preliminary result, this study finds that there is a significant positive impact of environmental dynamism on supply chain flexibility and this relationship is partially mediated by organisational ambidexterity. Moreover, the results reveal a significant positive impact among the variables; environmental dynamism, organisational ambidexterity and supply chain flexibility. In the practical context, managers need to be aware of environmental changes to identify areas which require investment in flexibility as it incurs both costs and risks for a firm. Further, the insights which managers gain on supply chain flexibility, from being responsive to dynamic environments is enhanced when organisational ambidexterity is practiced. Practicing organisational ambidexterity helps managers to refine existing processes to maintain competitive advantage, and achieve the optimal degree of flexibility required by the firm and its environment in being open to innovation. Owing to limitations identified, future research possibilities are extending the research to other industries, carrying out longitudinal studies, and testing other possible mediator variables.

Keywords: Supply Chain Flexibility, Environmental Dynamism, Organisational Ambidexterity
Palimpseste urbain au square Cabot de Montréal : quand l’urbanisme colonial rencontre la résistance autochtone
Authors: Guimont-Marceau Stéphane , Buckell Jennifer , Drouin-Gagné Marie-Ève , Léonard Naomie , Ainsley-Vincent Raphaëlle
Published: April 2024

Cet article se propose d’étudier une place publique de Montréal, au Québec, afin d’illustrer le déploiement dans la ville de différents processus de colonisation, de marginalisation et de résistance. L’étude du square Cabot met en évidence les strates de déplacement et de réappropriation qui forment un palimpseste inscrit dans les espaces urbains. Les autrices jettent un nouvel éclairage sur le contexte contemporain en l’étudiant à l’échelle d’un lieu et en le réinsérant dans le contexte du colonialisme de peuplement où s’entremêlent étroitement les relations sociales, politiques et économiques au Canada. Les villes jouent un rôle majeur dans les dynamiques coloniales et dans les processus de marginalisation, ainsi que dans la division coloniale de l’espace qui positionne certaines populations à l’extérieur des espaces de pouvoir. Le square Cabot s’inscrit dans ces dynamiques, mais il est aussi un lieu de réappropriation, puisque les services aux personnes en situation d’itinérance, les activités culturelles et les projets d’économie sociale qui s’y croisent placent ce lieu public au cœur de rencontres quotidiennes. L’étude du square Cabot en tant que lieu de relations, d’histoires et de pratiques, diverses et souvent contradictoires, révèle des processus de création d’espaces urbains et de préservation d’espaces autochtones. Ce faisant, elle lève le voile sur des couches de colonialisme et de résistance autochtone qui se chevauchent à travers l’histoire et interagissent pour former le paysage urbain actuel, celui du square et au-delà. Avec cet article, les autrices cherchent à rendre compte des tensions et des complexités de la création d’espaces urbains, dans un contexte colonial de peuplement où les histoires et significations des lieux ont été effacées par le pouvoir colonial, mais aussi maintenues en vie autant que possible grâce à des stratégies de préservation d’espaces autochtones.
Determination of Electrodynamic Forces between Coaxial Coil Turns with Current of Various Configuration
Authors: Tsitsikyan G. N. , Antipov M. Yu.
Published: April 2024

Determination of electrodynamic forces, as may be required for various practical purposes, is based on known calculation recommendations for mutual inductance coefficients, including the calculation methods with special functions, like complete elliptic integrals of the 1st and the 2nd kind, as well as spherical Legendre functions of the 2nd kind with half-integer index [1–5]. Some examples of practical tasks requiring these calculations are the assessments of mutual inductances in non-contact chargers, as well as the assessments of electrodynamic interactions in the windings of transformers, inductors, various solenoid-based loading devices, electric drives, etc. These applications are discussed in numerous publications and guides, e.g. [6–9].
Impact of Electrification in the Road Transport Sector on the Level of Electricity Consumption and Daily Load Curve in the UES of Russia
Authors: Veselov F. V. , Solyanik A. I. , Alikin R. O.
Published: April 2024

The article assesses the impact of potential motor transport sector electrification on the value of the aggregate demand for electricity and capacity in the UES of Russia. Despite official documents suppose quite modest quantitative targets for the electric transport until 2030, in the longer term, a large-scale replacement of oil fuel with electricity will have a significant effect on reducing greenhouse gas emissions, but will also require a more intensive development of generating and network capacities in the electric power industry. The scenaric forecast for the development of electric transport is made with the allocation of three segments - cars, trucks and buses, which allows taking into account the characteristics of electricity consumption characteristic of each of them. Another important result is an assessment of the possible extent of the influence of electric transport on the configuration of a typical daily load curve. The paper considers various modes of using infrastructure for electric transport charging, which result in different daily load curves. It is shown that, depending on the scales of electric transport development, their annual electricity consumption in the country will lay in the diapason from 168 to 460 TWh. At the same time, depending on the charging mode of electric vehicles, the additional power demand will vary from 26 to 74 million kW, and the amplitude of fluctuations in the hourly loads of electric vehicles will vary from two to four times.
On the Issue of Calculating the Reverse Arc Breakdown Voltage of a High-Voltage Thermionic Diode and Its Maximum Specific Electrical Power
Authors: Onufrieva E. V. , Onufriev V. V.
Published: April 2024

The issues of creating powerful power propulsion systems (PPS) based on a thermionic reactor-converter (TRC) and electric rocket propulsion systems (ERPS) are related to the development of compact high-temperature radiation–resistant current conversion systems (CCS) using plasma electric power devices - grid key elements (GKE) and high-voltage plasma thermionic diodes (HVPTD). The main problem of the development of GCE and HVPTD is the determination of their operating voltage (or reverse arc breakdown voltage in the locked state), which together with the current density in the conductive state characterizes the electric power density of the valve and is its main parameter. Within the framework of this work, the authors, based on the study of the locked state, numerically and analytically obtained new dependences for calculating the reverse arc breakdown voltage and determined the limiting values of the electrical power density of the HVPTD.
Principles of Multivariate Analysis in the Reltran Program for the Problems of Estimating Public Exposure Doses during the Decommissioning of Nuclear Facilities
Authors: Kiselev A. A.
Published: April 2024

The article represents the approaches introduced in the RELTRAN code developed under the FTP NRS-2 to modeling the radiation consequences for the population caused by possible releases of radioactive substances into the atmosphere during the planned work on the decommissioning of nuclear facilities. One of the tasks of the RELTRAN code is to perform calculations of the consequences of radioactive releases for the population for the tasks of justifying radiation safety. Several modeling options are considered: calculations based on average concentrations over several years, calculations based on average concentrations over several years, considering the schedule of the decommissioning process, case-study modeling approach based on historical meteorological series analysis and case-study modeling approach based on historical meteorological series analysis, considering the schedule of the decommissioning process. It was obtained that, depending on the duration of the planned process and depending on the season, the results differ significantly, for medium-term work, their seasonality becomes an important factor, at the same time, work with conditionally constant emissions lasting more than 6 months has a negligible uncertainty associated with time start of work.
Decomposition of a Decision-Making Problem Into Levels of Preference of the Majority Graph
Authors: Smerchinskaya S. O. , Yashina N. P.
Published: April 2024

Decision-making problems with a large number of alternatives are considered. It is proposed to preliminarily narrow the initial set of alternatives, excluding the obviously worse options. For this purpose, the decomposition of the original problem into preference levels of the majority graph is carried out. Graph levels containing the least preferred alternatives are removed. An algorithm for constructing an aggregated full quasi-order for ordering the set of best alternatives is developed. Majority graph preference levels are used to rank alternatives using Hamiltonian paths in a digraph. An algorithm for finding Hamiltonian paths in a digraph is proposed by raising the adjacency matrix to a power. An applied problem of ordering drone models using an algorithm for constructing a complete quasi-order is presented.
On the Stable Solution of the Problem of Compensating Nonsmooth Additive Disturbances with the Help of Feedback Laws
Authors: Maksimov V. I.
Published: April 2024

The problem of the feedback control of a system of ordinary differential equations, nonlinear in phase variables, subjected to the effect of an unknown nonsmooth disturbance is discussed. The problem consists of constructing a control action formation law that guarantees compensation for a nonsmooth disturbance; i.e., it guarantees that the phase trajectory (as well as the rate of its change) of the given system follows the prescribed phase trajectory (as well as the rate of its change) for any admissible realization of the disturbance. Two cases are considered. In the first case, admissible disturbances are constrained by instantaneous restrictions, and in the second case, any function that is an element of the space of Lebesgue measurable functions summable with the square of the Euclidean norm can be an admissible disturbance. The problem is solved under conditions of inaccurate measurement at discrete times of the phase states of both systems. In the presence of instantaneous restrictions on disturbances, the problem is also solved by measuring some of the phase states. Algorithms for solving this problem, oriented towards computer implementation, are designed that are resistant to information interference and computational errors. Estimates of the rate of convergence of the algorithms are given.
Necessary and Sufficient Conditions for an Extremum in Complex Problems of Optimization of Systems Described by Polynomial and Analytic Functions
Authors: Nefedov V. N.
Published: April 2024

When studying complex optimization and control problems for systems described by polynomial and analytic functions, there is often a need to use necessary and sufficient optimality conditions. Moreover, if the known conditions turn out to be inapplicable, it is required to develop as subtle conditions as possible. This problem is studied in this article. The necessary and sufficient conditions for a local extremum are formulated for polynomials and power series. With a small number of variables, these conditions can be tested using practically implemented algorithms. The main ideas of the proposed methods involve using the Newton polytope for a polynomial (power series) and the expansion of a polynomial (power series) into a sum of quasi-homogeneous polynomial forms. The obtained results provide the practically applicable methods and algorithms necessary for solving complex problems of optimization and control of systems, which are described by polynomial and analytical functions. Specific examples of tasks in which the proposed technique can be used are given.
Nonreversible Motion of a System of Interacting Bodies Along a Rough Horizontal Straight Line
Authors: Bolotnik N. N. , Figurina T. Yu.
Published: April 2024

A locomotion system is considered in the form of a chain of a finite number of bodies (materi along points) moving in a straight line on a horizontal rough plane due to the forces of interaction between the bodies. These forces serve as the control variables. Dry Coulomb friction acts between the bodies and the plane. The necessary and sufficient conditions are obtained under which the nonreversible motion of all bodies of the system for the same distance is possible under the assumption that in the initial and final positions the velocities of all bodies are equal to zero. Nonreversible motion is understood as a motion in which none of the bodies changes the direction of their velocity in the process of moving.
Reinforcement Learning for Model Problems of Optimal Control
Authors: Semenov S. S. , Tsurkov V. I.
Published: April 2024

The functionals of dynamic systems of various types are optimized using modern methods of reinforcement learning. The linear resource allocation problem, as well as the optimal consumption problem and its stochastic modifications are considered. In the reinforcement learning strategy gradient methods are used.
Improvement of Incomplete Multiview Clustering by the Tensor Reconstruction of the Connectivity Graph
Authors: Zhang H. , Chen X. , Zhu Yu. , Matveev I. A.
Published: April 2024

With the development of data collection technologies, a significant volume of multiview data has appeared, and their clustering has become topical. Most methods of multiview clustering assume that all views are fully observable. However, in many cases this is not the case. Several tensor methods have been proposed to deal with incomplete multiview data. However, the traditional tensor norm is computationally expensive, and such methods generally cannot handle undersampling and imbalances of various views. A new method for clustering incomplete multiview data is proposed. A new tensor norm is defined to reconstruct the connectivity graph, and the graphs are regularized to a consistent low-dimensional representation of patterns. The weights are then iteratively updated for each view. Compared to the existing ones, the proposed method not only determines the consistency between views but also obtains a low-dimensional representation of the samples using the resulting projection matrix. An efficient optimization algorithm based on the method of indefinite Lagrange multipliers is developed for the solution. The experimental results on four data sets demonstrate the effectiveness of the method.
Stabilization of Programmed Motions of Constrained Mechanical Systems
Authors: Golubev A. E.
Published: April 2024

The problem of the stabilization of programmed trajectories of mechanical systems, taking the constraints on the values of generalized coordinates, velocities, and accelerations into account, is considered. The control is built using the backstepping method in combination with the use of logarithmic Lyapunov barrier functions. The stabilizing feedbacks obtained in this study, in contrast to similar known results, do not lead to an unlimited increase in the values of the control variables when the state variables of the system approach the boundary values. As an example, the problem of constructing and stabilizing the trajectory of the spatial motion of an underwater vehicle is considered.
Combination of Bases and an Evaluation of the Set of Extremal 3-Uniform Hypergraphs
Authors: Beretskii I. S. , Egorova E. K. , Mokryakov A. V. , Tsurkov V. I.
Published: April 2024

The main problem with hypergraphs is their storage. If the hypergraph does not contain singularities, then sparse matrices are often used to describe it. Adjacency matrices are often used to work with k-uniform hypergraphs, but they take up a large amount of space in computer memory and, in general, storage of k-uniform arrays is not very convenient. Here we propose one solution for describing and storing extremal k-uniform hypergraphs. This base is a unique characteristic of an extremal hypergraph that uniquely describes it. In addition, bases can be used to search for the power of extremal k-uniform hypergraphs. We present base enumeration algorithms and present a hypothesis about the analytical form of formulas describing the cardinality of the set of extremal k-uniform hypergraphs. For this task, the base combination operation, also introduced here, is used.
Resource Distribution and Balancing Flows in a Multiuser Network
Authors: Malashenko Yu. E. , Nazarova I. A.
Published: April 2024

Balancing strategies for control flows and resources are studied in computational experiments on a mathematical model of a multiuser network. An algorithmic scheme for sequentially solving a chain of lexicographically ordered problems of finding nondiscriminating the maximin distributions of flows is proposed. A procedure for step-by-step equalizing the splitting of internodal flows along all the existing shortest paths is developed. At each iteration, a part of the available resource is distributed equally among all pairs of correspondent nodes for which there is a possibility of flow transmission. The results obtained in the course of the experiments make it possible to trace the dynamics of changes in the capacity of the edges, up to reaching the maximum network load. Bottlenecks in various networks are analyzed and compared with a monotonic increase in the flows. Special diagrams are given.
Evolution of the Atmospheric Pressure Signal from Tonga Volcano when Moving Away from It
Authors: Chunchuzov I. P. , Kulichkov S. N. , Popov O. E. , Perepelkin V. G.
Published: April 2024

A model of atmospheric pressure signal propagation from the eruption of the Hunga–Tonga—Hunga–Haʻapai volcano (hereafter abbreviated as Tonga) is proposed. The model is used to explain some peculiarities in the changes in the wave form of the observed signal with increasing distance from the volcano. The model is based on the solution of the linearized Korteweg de Vries (KDV) equation, which describes the change in the wave form of the Lamb wave as a function of distance from the source. We compare the observed and model signals obtained as a superposition of the Lamb wave and the acoustic modes calculated for three infrasound stations (IS22, IS24, and IS30). The energy of the volcanic eruption is estimated from the pressure amplitude and characteristic duration of the signal recorded at one of the infrasound stations closest to the volcano (IS24).
Comparison of Results of Long-Term Measurements of Stratospheric and Tropospheric Column NO2 Contents using Satellite Ozone Monitoring Instrument to Results of Ground-Based Measurements
Authors: Gruzdev A. N. , Elokhov A. S.
Published: April 2024

Results of measurements of NO2 contents in vertical columns of the stratosphere and troposphere using the Ozone Monitoring Instrument aboard the EOS–Aura satellite in 2004–2020 are compared to results of ground-based measurements at stations of the Network for the Detection of Atmospheric Composition Change (NDACC), first of all, to results of measurements at the Zvenigorod Scientific Station (ZSS) of the A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences. The comparison of satellite data to the ZSS data is done using the both products of satellite measurements—the stratospheric and tropospheric column NO2 contents. When comparing the data of OMI and ground-based measurements at other stations, satellite values of the NO2 content in the stratospheric column are compared to values of the total column NO2 content obtained in ground-based measurements. Correspondence between the results of satellite and ground-based measurements is characterized by the magnitude of the difference between them, linear correlation coefficients and regression coefficients. The difference has a noticeable seasonal variation. Correlation and regression coefficients depend significantly on the season. Characteristic patterns of correlation coefficient changes with latitude as well as features of correlation between satellite and ground-based data in the polar and middle latitudes of the southern hemisphere in spring have been revealed. For some stations, the dependence of the quantitative characteristics of the correspondence between the results of satellite and ground-based measurements on cloudiness has been revealed. Under cloudless conditions at the ZSS, a weakening of the correlation between satellite and ground-based values of the stratospheric NO2 content and an increase in the correlation between the values of the tropospheric NO2 content is noted. The dependence of the correspondence characteristics between the data of satellite and ground-based measurements on the level of pollution of the lower troposphere with nitrogen oxides has been revealed. The correlation between the values of the tropospheric NO2 content in the vicinity of the ZSS under strong pollution increases, while the correlation between the values of the stratospheric NO2 content decreases. Based on the results of the comparison of satellite and ground-based data, estimates of the upper threshold values of the tropospheric NO2 content at different stations is obtained. The lowest values have been obtained for polar stations, and the highest value has been obtained for the ZSS which is most susceptible to anthropogenic pollution due to its proximity to the Moscow megapolis.
Baroclinic Model of Jupiter’s Great Red Spot
Authors: Suetin B. P. , Zhmur V. V. , Chkhetiani O. G.
Published: April 2024

The paper proposes a quasi-geostrophic baroclinic model of Jupiter’s Great Red Spot as a localized eddy formation in a continuously stratified rotating atmosphere under the action of a horizontal shear flow in the f-plane approximation. On the basis of the theory of ellipsoidal vortices, an analytical relationship is obtained between the geometric dimensions of the vortex, the potential vorticity of the vortex core, and the characteristics of the background flow. Measurements of a number of characteristics of both the vortex and the background current in the Voyager 1 (1979), Galileo (1996), and Cassini (2000) missions were used. Based on the theory, the vertical size of the Jupiter’s Great Red Spot was calculated, which turned out to be close to the same characteristic measured in the Voyager 1 (1979) mission. Based on the theory, an e-stimate of the vertical size of the Great Red Spot of Jupiter was obtained, which is consistent with the e-xperimental data of the Voyager 1 mission (1979).
On the Influence of Atmospheric Ions on Aerosol Formation: Numerical Modeling
Authors: Aloyan A. E. , Yermakov A. N. , Arutyunyan V. O.
Published: April 2024

A new mathematical model of the global transport of multicomponent gas impurities and aerosols has been constructed, including the formation of sulfate aerosols in the atmosphere in both hemispheres. Calculations of the nucleation rates and particle number concentrations were performed for the winter period in the troposphere using a unified model that takes into account chemical and kinetic transformation processes (photochemistry, nucleation, condensation/evaporation, and coagulation). Binary nucleation of sulfuric acid and water vapor was coupled with new-particle formation due to atmospheric ions. The numerical results indicate a significant role of ion nucleation in aerosol formation in the Northern and Southern hemispheres in winter. The factors controlling the dynamics of ionic processes in the atmosphere and their influence on the spatiotemporal distribution of aerosol particles involve not only the level of air ionization but also temperature, relative humidity, and the content of sulfur and water vapor in the air. At a height of 4.2 km, the formation of particle nuclei with the participation of ions occurs only over the Lake Baikal and Kamchatka regions as well as the regions of the northeast and northwest of the American continent. Within the regions of localization of this process in the atmosphere, the rate of new particle generation varies by more than an order of magnitude.
The Effect of Global Warming on the Atmospheric Lifetime of Odd Oxygen
Authors: Larin I. K.
Published: April 2024

Data on the effect of global warming on the atmospheric lifetime of odd oxygen, Ox. The results obtained characterize the effect at latitude 50°C. in the altitude range of 15–55 km in January–June 2000–2100s, the data for calculations were obtained using the interactive radiation-chemical two-dimensional SOCRATES model, with which the total rate of Ox death in the Ox, HOx, NOx, ClOx and BrOx catalytic cycles, as well as the concentration of Ox equal to the sum of the concentrations of O3, O(3P) and O(1D) for the above conditions, which are necessary for calculating the lifetime of Ox, were preliminarily calculated. Scenarios of the Intergovernmental Panel on Climate Change (IPCC) were used as initial conditions for calculations using the SOCRATES model RCP 4.5 and RCP 6.0 for the above conditions.
Near-Surface Air Content of CH4, СО2, СО and δ13C–СH4 in Moscow According to In Situ Observations
Authors: Berezina E. V. , Vasileva A. V. , Moiseenko K. B. , Pankratova N. V. , Skorokhod A. I. , Belikov I. B. , Belousov V. A. , Artamonov A. Y.
Published: April 2024

Near-surface observations of air mixing ratios of CH4, CO2, CO, benzene, and δ13C–СH4 at the IAP-RAS site in Moscow for years 2018–2020 are analyzed to describe typical interannual, seasonal, and diurnal variations. The highest mixing ratios of CH4, CO2, and CO (above 2.2, 430, and 0.2 ppmv, respectively) are mostly observed in winter as a result of the seasonal maxima in the emissions of these gases from motor transport and energy sectors and the slow removal of the emissions from the near-surface air due to suppressed turbulent vertical mixing in the cold season. The highest impact of local and distant microbial emissions on the CН4 mixing ratios is observed in summer, as follows from the low δ13C–СH4 values from –50 to –60‰. The highest increase in the mixing ratios of all the measured species is associated with air transport from the industrial area located at the east – southeast from the site. The estimated emission ratios CH4/benzene = = 0.52–0.54 ppmv/ppbv, СH4/СО = 0.56–0.75 ppmv/ppmv, СО2/benzene = 77–93 ppmv/ppbv, СО2/СО = = 81–131 ppmv/ppmv, СО/benzene = 0.65–1.11 ppmv/ppbv show the prevailing contribution of emissions from motor transport and energy sectors to the content of trace gases in the near-surface air in Moscow and are consistent with other similar estimates published on the basis of observations in large cities.
Influence of the Weak Surface Film on Formation and Propagation of Wind Waves in a Channel
Authors: Plaksina Yu. Yu. , Pushtaev A. V. , Vinnichenko N. A. , Uvarov A. V.
Published: April 2024

Processes of the wind waves formation remain poorly understood, despite the numerous studies. One of the main reasons, in our opinion, is that simplified theoretical analysis does not take into account the weak film of natural contaminants. In the present work waves generation in two channels is experimentally studied and compared for ethanol, water and water with addition of soluble surfactant SDS (sodium dodecyl sulphate) in various concentrations. The employed concentrations hardly affect the surface tension coefficient, but lead to significant modification of the subsurface flow structure. In ethanol the surface film is not formed, so it can be considered as reference case. In water and water with added surfactant the film gets broken and the surface becomes clean at certain critical wind speed, which grows for increasing surfactant concentration. For the surface to remain clean, the contaminant adsorption to the surface must be compensated by its removal by the tangential stress. Three experimental techniques are used to study the influence of cool skin on formation of the wind waves. The surface relief is measured with modified color schlieren technique and the liquid velocity fields are determined with Particle Image Velocimetry (PIV). The surface temperature fields, which allow identification of the regions of the cool skin rupture, are obtained with IR thermography. IR thermography is also used to study the surface velocity field (IR PIV). The film is shown to have significant influence on both the waves amplitude and the structure of subsurface flow.
Comparison of Cluster Analysis Methods for Identification of Weather Regimes in Euro-Atlantic Region for Winter and Summer Seasons
Authors: Babanov B. A. , Semenov V. A. , Mokhov I. I.
Published: April 2024

Various methods of cluster analysis are used for identification of large-scale atmospheric circulation regimes or weather regimes (WRs). In this paper we compare four most commonly used clustering methods – k-means (KM), Ward’s hierarchical clustering (HW), Gaussian mixture model (GM) and self-organizing maps (SOM) to analyze WRs in Euro-Atlantic region. The data used for WRs identification are 500 hPa geopotential height fields (z500) from the ERA5 reanalysis for the 1940–2022 period. Four classical wintertime weather regimes are identified by the KM method – two regimes associated with positive and negative phases of the North Atlantic Oscillation (NAO+ and NAO–), a regime associated with the Scandinavian blocking (SB) and a regime characterized by elevated pressure over the Northern Atlantics. For summer months KM method gets WRs that are similar by their spatial structure to the classical winter ones. The SOM method yields results that are almost identical to the results of KM method. Unlike KM and SOM methods, HW and GM do not catch the spatial structure of all four classical winter Euro-Atlantic weather regimes and their summer analogues. Compared to WRs of the KM and SOM methods, WRs obtained by HW and GM methods explain less z500 variance, they have different occurrences, persistence and transition features. Summer and winter WRs obtained by HW and GM methods are less similar to each other compared to WRs provided by KM method. Average spatial correlation coefficients between mean z500 fields of WRs obtained by KM and HW methods are 0.76 in winter and 0.83 in summer, 0.70 in winter and 0.72 in summer for KM and GM methods and 0.41 in winter and 0.44 in summer for the regimes between HW and GM methods, respectively. There are statistically significant trends of seasonal occurrence of WRs found by some of the studied clustering methods – a positive trend for the occurrence of the NAO+ regime and a negative trend for the occurrence of the NAO– regime.
The Response of the Tropospheric Dynamics to Extreme States of the Stratospheric Polar Vortex during Enso Phases in Idealized Model Experiments
Authors: Zyulyaeva Y. A. , Sobaeva D. A. , Gulev S. K.
Published: April 2024

Extreme states of the stratospheric polar vortex (SPV) affect the average position of the main propagation trajectories of synoptic vortices in the Northern Hemisphere over a time period from 2 weeks to 2 months. This time scale is considered to be one of the most difficult periods in forecasting. Based on the analysis of data from idealized numerical experiments on the Isca platform, we studied the processes of formation of anomalous positions of storm tracks in the Atlantic-European region as a response to sudden stratospheric warmings and events of extremely strong SPV during various phases of the El Niño Southern Oscillation. It was shown that in winter it is impossible to say unambiguously about the southward displacement of the Atlantic storm track during El Niño events without taking into account the intensity of SPV. The intensity of SPV, expressed as the zonal component of wind speed, averaged along 60° N at the level of 10 hPa, has its maximum predictive potential during El Niño.
COLLECTION OF SUBMICRON AEROSOL PARTICLES BY FILTERS COMPOSED OF NANOFIBERS
Authors: KIRSH V. A. , KIRSH A. A.
Published: April 2024

The deposition of aerosol particles from a Stokes flow in filters composed of nanofibers has been considered at Knudsen numbers Kn ∼ 1. The efficiency of particle collection by model filters with 2D and 3D structures has been determined by numerical simulation as depending on particle radius rp , filter parameters (nanofiber radius a, packing density α and filter thickness), and filtration conditions taking into account the gas slip at the fibers.It has been shown that the efficiencies of particle collection by nanofibers in model 2D and 3D filters are almost equal at the same low packing density 0.02. It has been found that the dependence of the penetration of particles on their radius at a constant velocity on the order of several centimeters per second and at Kn ∼ 1 passes through a maximum, which corresponds to particle radius rp ∼ a. The calculated sizes of the most penetrating particles agree with experimental data. The results obtained will be used when selecting aerosols for testing nanofibrous filters.
INTERACTION OF GOLD AND NICKEL NANOPARTICLES WITH MOLECULAR HYDROGEN AND CARBON MONOXIDE IN THE PRESENCE OF AN ELECTRIC FIELD
Authors: GRISHIN M V , GATIN A K , GOLUBEV E K , DOKHLIKOVA N. V. , OZERIN S. A. , SARVADI S. YU. , STEPANOV I. G. , SLUTSKII V. G. , KHARITONOV V. A. , SHUB B. R.
Published: April 2024

A nanostructured gold–nickel coating has been synthesized on the surface of pyrolytic graphite. Its physicochemical properties have been studied by scanning tunneling microscopy and spectroscopy, Auger spectroscopy, mass spectrometry, and other methods. It has been found that the coating consists of clusters formed by gold and nickel nanoparticles. It has been shown that an electric field can inhibit or stimulate the adsorption of hydrogen on gold and the reduction of the oxidized surface of nickel nanoparticles with carbon monoxide. The mechanisms of the influence of the field on the chemical processes involving H2 and CO are different. Quantum-chemical simulation has made it possible to determine the values of the energy barriers for CO adsorption on nickel nanoparticles.
THE STUDY OF THE BEHAVIOR OF AQUEOUS POLY(VINYL ALCOHOL) SOLUTIONS EXPOSED TO UV RADIATION
Authors: NEKRASOVA N. V. , KHLEBNIKOVA O. A. , LOMOVSKOY V. A. , KADYKO M. I. , VYSOTSKII V. V. , GALUSHKO T. B. , KAZBEROV R. YA.
Published: April 2024

Abnormal changes have been found in the viscosity of aqueous poly(vinyl alcohol) solutions with different concentrations (1–8%) exposed to UV irradiation for 0–60 min. A molecular mechanism of this phenomenon has been proposed based on the assumption of a rearrangement in the hydration shells of the functional groups of poly(vinyl alcohol) as a result of changes in the environment under the influence of UV irradiation.
DYNAMIC SURFACE PROPERTIES OF FIBRIN
Authors: MILYAEVA O. YU. , RAFIKOVA A. R.
Published: April 2024

Fibrin is formed via polymerization of one of the main blood proteins, fibrinogen, under the action of an enzyme, thrombin. Dynamic surface elasticity and dynamic surface tension of mixed solutions of fibrinogen and thrombin are measured as functions of surface age and enzyme concentration (50–800 U/L). The nonmonotonic pattern of the dependences for the dynamic surface elasticity indicates the multistage character of fibrin film formation and makes it possible to monitor the transition from unfolded protein to individual filamentous aggregates; a network of branched fibrils; and, finally, a continuous film. The dynamic surface elasticity of fibrin films is twofold higher than the corresponding values for fibrinogen (115 and 55 mN/m, respectively). The use of different types of microscopy makes it possible to assess the morphology of the obtained films.
NANOEMULSIONS OF POLYOXYETHYLENE(4) LAURYL ETHER WITH SOLUBILIZED CHLORHEXIDINE BASE
Authors: ZADYMOVA N. M. , MALASHIKHINA A. A.
Published: April 2024

Nanoemulsions (NEs) of simple compositions have been obtained, in which polyoxyethylene(4) lauryl ether (Brij L4, Br-4) plays the roles of a dispersed phase and a stabilizer, while water is a dispersion medium. The following properties of NEs have been studied: particle size distribution; solubilization capacity; and transport properties with respect to the lipophilic biocide, chlorhexidine (CH) base. The long-term aggregative stability of NEs (for several months) and the efficient mass transfer of CH by the NE dispersed phase particles in the aqueous medium have been confirmed. A unique phenomenon of a spontaneous decrease in the sizes of NE droplets upon solubilization of CH has been found, with the particle average diameter decreasing from 52 ± 6 to 19 ± 3 nm. The reason for this phenomenon is the formation of complexes between Br-4 and CH molecules on the surface of the droplets, with the complexes being better soluble in water than Br-4. Brij L4 molecules included into the complexes are transferred from the droplet surface into the dispersion medium, thus leading to the decrease in the droplet sizes. The complexation occurs due to the formation of multiple N⋅⋅⋅H⋅⋅⋅O hydrogen bonds. From 84 to 96% of the biocide solubilized in the NEs is also localized in the polyoxyethylated layer of Br-4 droplets due to H-bonds.
EFFECT OF THE HYDRODYNAMIC CONDITIONS FOR SODIUM ALGINATE–PAPAIN COLLOIDAL SYSTEM SYNTHESIS ON THE SORPTION PROPERTIES OF THE BIOCOMPOSITE
Authors: KOKSHAROV S. A. , LEPILOVA O. V. , ALEEVA S. V. , KRICHEVSKII G. E. , FIDOROVSKAYA YU. S. , OLTARZHEVSKAYA N. D.
Published: April 2024

The regularities have been studied for the formation of molecular associates upon the introduction of papain into a sodium alginate colloidal solution in the laminar low-speed, transient, and turbulent stirring regimes. The relationship between variations in the sorption capacity of the biopolymer composition and the kinetic regularities of the interphase transfer has been studied during the sorption binding of albumin, which is one of the protein-based components of wound exudates, with such components being subject to ensimatic cleavage. The state of the dispersed phase of the colloidal solutions has been estimated by the dynamic light scattering method. The properties of the formed biopolymer films have been studied using the methods of scanning electron microscopy, low-temperature nitrogen adsorption, and static albumin sorption from solutions of limited volumes. The data of the sorption experiments have been analyzed using the Boyd, Morris–Weber, and gel diffusion models, as well as the Lagergren pseudo-first-order and Ho–McKay pseudo-second-order kinetic models. The data have been obtained for substantiating the dosages of the biopolymermatrix used on wound-healing bandages and for the efficient binding of wound necrotic contamination during the time preset according to the technical requirements.
Nanoparticle Concentration as an Important Parameter for Characterization of Dispersion and Its Applications in Biomedicine
Authors: Pashirova T. N. , Shaihutdinova Z. M. , Souto E. B. , Masson P. , Mironov V. F.
Published: April 2024

Currently, there are problems to standardize methods for determining the concentration of nanoparticles and creation of etalon materials for calibrating measured concentrations. Accurate determination of nanoparticle concentration is necessary to assess the maximum dose of administered nanotherapeutics for diagnostics and therapy in vivo, to determine the order of reaction in enzymatic nanoreactors. In addition, this parameter determines biological effects, such as the formation of a protein corona on the outer surface of nanoparticles that precedes nanoparticles’ absorption and internalization in cells. This review discusses the most common methods for determining the concentration of nanoparticles based on direct visualization, using microscopy, light absorption or light scattering, direct counting of nanoparticles, and gravimetry. Results may differ from one method to the other. Thus, the use of a combination of several methods provides more reliable results. The advantages, disadvantages and ways to improve accuracy of results are also presented.
Biocompatible Hydrogels Based on Biodegradable Polyesters and Their Copolymers
Authors: Fomina Yu. S. , Semkina A. S. , Zagoskin Yu. D. , Aleksanyan M. M. , Chvalun S. N. , Grigoriev T. E.
Published: April 2024

Poly(ethylene glycol)-based hydrogels have long proved to be promising materials for various biomedical technologies. This review considers systems based on the most common and studied copolymers of poly(ethylene glycol) and biodegradable polyesters of lactide and glycolide. Traditional and modern approaches to the synthesis of the copolymers and the production of hydrogels have been considered, the studies of the structure and properties of the materials have been analyzed, and the main directions of the application of these products in practice have been described.
On the Rheology of Thixotropic and Rheopexic Suspensions
Authors: Levinsky A. I.
Published: April 2024

Semi-empirical equations are derived that describe the dependence of shear stress on shear rate during the flow of a one-component suspension. The suspension is considered as consisting of two fractions: single grains of the solid phase and their dimers, between which a reversible dimerization reaction occurs. In this case, the dimerization of single grains is considered as a reaction with an invariable rate constant, and the dissociation of dimers is considered as an inverse reaction with a rate constant that increases linearly with the shear rate. The equations are based on the Krieger−Doherty formula, generalized to the case of a multicomponent suspension.
Models for Stabilization of Charged Particles with Surfactants in Nonpolar Media
Authors: Popovetskiy P. S.
Published: April 2024

Stabilization of charged particles in nonpolar media is one of the most complicated problems in modern colloid chemistry. The attribution to colloid chemistry is absolutely justified in this case: in nonpolar media, charged particles have, as a rule, a supramolecular nature. Low dielectric permittivity of a medium makes the existence of ions in the classical interpretation energetically disadvantageous. The key condition for the presence of charged particles in nonpolar media is their steric stabilization, which requires some revision of the classical concepts of the structure of the electrical double layer, primarily, its diffuse part. Detailed analyzing the structure of the electrical double layer in nonpolar media is of importance because of the high practical significance of electrokinetic phenomena in such systems. This review considers the main models for steric stabilization of charged particles with surfactants in dispersion media having dielectric permittivities lower than 5. The main attention is focused on not only the concentrations corresponding to the formation of reverse micelles, but also on the concentrations below the critical micelle concentration. In addition, nontypical examples of electrokinetic phenomena in organosols are considered.
Mechanochemical Synthesis of Ethoxyaminohumic Acids and Surface-Active Properties of Their Solutions at Solution–Air Interface
Authors: Khil’ko S. L. , Shelest V. S. , Rogatko M. I. , Makarova R. A. , Semenova R. G.
Published: April 2024

Ethoxyamine derivatives of humic acids have been obtained by mechanochemical synthesis via the simultaneous interaction of humic acids with poly(ethylene glycol) (PEG-6000 and PEG-1500) and an aminating reagent (urea, hydroperitum, or cyanoguanidine) in a vibrating apparatus. Reaction products have been characterized by IR spectroscopy, acid–base potentiometric titration, and viscometry. Tensiometric and rheological characteristics of the surface layers of solutions of salts of the synthesized derivatives of humic acids have been studied by the pendant drop and oscillating pendant drop methods. The solutions of the salts of ethoxyaminohumic acids have been found to exhibit a pronounced surface activity at the air–water interface. The experimental dependences of the viscoelastic modulus on the surface pressure and the concentration of the solutions of ethoxyaminohumic acid salts are in satisfactory agreement with the functions calculated in terms of the theoretical model of bimolecular adsorption. The presence of amino groups in the structure of ethoxyaminohumic acids predetermines their high solubility in the acidic pH region. The simultaneous incorporation of ethoxy and amino groups into humic acid macromolecules makes it possible to obtain a novel type of surfactants, which combine three functions, i.e., the functions of anionic, cationic, and nonionic surfactants.
SELF-ASSEMBLY AND PHOTOINDUCED DEFORMATION OF MICROSPHERES OF AN AZO MOLECULE CONTAINING A 1,4,3,6-DIANHYDROSORBITOL CORE AND CINNAMATE PERIPHERAL GROUPS
Authors: Ai X. T. , Wang L. E. , Luo X. , Tang B. , Li S. L. , Zhu H. E. , Tang H. L. , Li Y. B. , Yang C. L. , Lv W. Y.
Published: April 2024

This study investigated the controllable fabrication of anisotropic particles with different sizes and morphologies via self-assembly and photoinduced deformation of azo colloidal microspheres, which were formed from a typical azo molecular material (IAC-4) that contains a 1,4,3,6-dianhydrosorbitol core and the cinnamate peripheral groups. Firstly, azo colloidal microspheres were obtained by self-assembly via gradually adding deionized water into IAC-4 solution of tetrahydrofuran. For precisely controlling the length of short axis of anisotropic particles, IAC-4 colloidal microspheres with different and uniform sizes were obtained by adjusting the IAC-4 concentration, adding rate of water and stirring rate. The size of colloidal microspheres becomes smaller with the increase in IAC-4 concentration, the adding rate of water and the stirring rate. Finally, IAC-4 colloidal microspheres in the solid state, perpendicularly irradiated by the linearly polarized laser beam (λ = 488 nm), were irreversibly and controllably stretched into anisotropic particles with the different morphologies, length of long axis and axial ratio via adjusting the irradiation time and the power of laser beam.