Modification of the RLA model for presenting a cluster system of a composite material with a fractal filler structure

The paper proposes a modification of the diffusion-limited aggregation model to study the properties of a cluster system. A computational experiment to determine the mutual influence of the sticking probability and the volume concentration of particles on the formation of fractal clusters in a cluster system was carried out in accordance with the second-order orthogonal central compositional plan (OCCP). As a result of a computational experiment in accordance with the OCCP, an equation was obtained for the dependence of the mass fractal dimension of clusters on the volume of particle concentration and the probability of adhesion of diffusing particles and cluster particles in the adhesion zone. This dependence was obtained in a range of volume concentration of particles from 2 to 5 % and the probability of adhesion of diffusing particles and particles of clusters in the adhesion zone from 0.2 to 1.

METHODOLOGY OF CONVERTING OF THE COORDINATES OF THE BASIS ATOMS IN A UNIT CELL OF CRYSTALLINE Β-GA2O3, SPECIFIED IN A MONOCLINIC CRYSTALLOGRAPHIC SYSTEM, IN THE LABORATORY CARTESIAN COORDINATES FOR COMPUTER APPLICATIONS

One of the most important areas of modern technology is the creation of new structural materials with predetermined properties. Along with industrial methods for their preparation and technologies associated with the artificial growth of crystalline structures, various methods of computer modeling of new materials have recently become increasingly important. Such approaches can significantly reduce the number of full-scale experiments. Many applications of the computational materials science are related to the need to establish a relationship between structure and electronic characteristics, and other physical properties of crystals. This article on the example of crystalline β-Ga2O3 presents the algorithms used in the converting of the coordinates of the basis atoms in a unit cell of crystal, specified in a crystallographic system, in the Cartesian coordinates for the computational experiment.

Gender aspects of entrepreneurial opportunities and abilities

To date, the involvement of the population in the creation of a business has become an urgent problem. Therefore, the purpose of our study was to determine the opinions of adults that have developed in various states about the opportunities and abilities they have to open their own enterprises. The results of a survey of the adult population on this problem were used as empirical data. The survey conducted in 2018 covered 59 states located in different parts of the world. Our study was aimed at assessing the existing gender differences. The computational experiment allowed the development of six mathematical models. The study showed that in most countries men are more optimistic about their opportunities and abilities to participate in entrepreneurial activities.

Potential in microroughness domain of metal surface employed in cathodic protection mode

This effort presents the results of investigation of cathodic protection process of a section of the main pipeline, which has been operating in cathodic protection mode for a long time and which insulation has completely exfoliated from metal surface, and a cavity between is filled with water and salt impurities. In this case, a decisive factor is a fact that a metal surface is covered with microroughnesses in the form of protrusions with almost conical shape. The surface is immersed in electrolyte. At the electrolyte-metal interface, a potential difference is formed - a corrosion potential, which creates an unstable equilibrium among the potentials of metal and electrolyte. A mathematical model is designed and implemented into a numerical algorithm and computer program. A computational experiment has been carried out to calculate the potential around microroughness. The model describes a change in potential in this area at incomplete and complete cathodic protection of metal surface. The basis of computational model is a selection of one of metal protrusions of material microheterogeneity and placing it in a cylinder, which diameter coincides with that one of the lower base of this protrusion, and its upper part passes through the apex of the protrusion. Mathematical model equations with corresponding boundary conditions and their discrete implementation are presented. The solution of problems is obtained by iterative procedures based on reference values of protective potential taken from practice. The results of computational experiment are presented in the form of graphs: 1) potential distribution in the field of electrolytes; 2) changes in electrolyte potential at the border with protrusion at different values of polarization potential; 3) changes in polarization resistance in the area (calculated). The geometry of computational domain was also varied, and the values of protective potential were determined to ensure the absence of corrosion. Keywords: corrosion, microroughness, protective potential, plastic current density, electrolyte

Stability of synchronous modes of the system of two connected self-oscillators

In this paper investigate the dynamic instability of a system of two self-oscillators with a strong resonant coupling. The analysis of influence of resonance properties of coupling on stability of synchronous modes was carried out. In the course of the computational experiment, it was possible to observe the different behavior of the system depending on the given initial conditions. The boundaries of destruction of coherent modes are determined.

On the Issue of Designing a System for Continuous Control of Road Materials Compaction for Pavers

The results of the research on the creation of an automatic compaction control system (ACCS) for pavers in real time are considered. The research is based on the methods of artificial neural networks (ANN). In this paper, an ANN model is obtained, with the help of which it is possible to determine the compaction coefficient (CC) of an asphalt mixture. The input variables of the ACCS are the velocity of movement of the paver, the frequency of impacts of the tamper, the force in the pusher of the tamper, the type of mixture, the thickness of the layer. The results of a computational experiment on the calculation of Cc in real time are presented. The ANN is able to explain more than 98 % of the measured data.

COMPUTATIONAL EXPERIMENT TECHNOLOGY IN RESEARCH OF POWER INDUSTRIES WHEN IMPLEMENTING THREATS TO ENERGY SECURITY

В работе представлен алгоритм проведения вычислительного эксперимента на примере реализации одной из угроз энергетической безопасности «Недостаток инвестиций в отрасли энергетики» с использованием когнитивных и экономико-математических моделей. Рассмотрены особенности включения инвестиционной составляющей в модель оптимизации вариантов развития ТЭК с учетом энергетической безопасности. Представлена когнитивная модель для анализа угрозы «Недостаток инвестиций в отрасли энергетики». Дается описание ПК ИНТЭК-А, обеспечивающего возможность интеграции когнитивных и математических моделей. The paper presents an algorithm of computational experiment on the example of the implementation of one of the threats to energy security "Lack of investment in the energy sector" using cognitive and economic-mathematical models. The features of the inclusion of the investment component in the model of optimization of options for the development of the fuel and energy complex, taking into account energy security, are considered. A cognitive model for analyzing the threat “Lack of investment in the energy sector” is presented. The description of PC INTEC-A, which provides the ability to integrate cognitive and mathematical models, is given.

Processing and visualization of the results of parametric numerical calculations

In modern problems of mathematical modeling in computational gas dynamics, it is increasingly necessary to implement parametric studies. In these cases, the key factors of the problem under consideration vary with the chosen step within the given ranges. Calculations of this kind can be effectively carried out by constructing a generalized computational experiment. A generalized computational experiment is a computational technology that combines the solution of mathematical modeling problems, parallel technologies, and visual analytics technologies. The results of a generalized computational experiment are multidimensional arrays, where the dimension of the arrays corresponds to the number of key factors. Processing and visual presentation of such arrays requires solving a number of separate tasks. The processing and visual presentation of the results are carried out for target functionals represented as a function of many variables. The report presents an examples of solving specific processing and visualization problems based on the implemented generalized computational experiment for 3D cone in supersonic flow.

Assessment of Influence of Residential Area Planning Structure on Air Quality Using Numerical Modeling

Numerical study of the aeration of a new urban microdistrict located along a highway in Novosibirsk, Russia, was performed. The main goal of the paper was to assess whether the architectural and planning structure of the new microdistrict is optimal in terms of aeration and air quality. A scenario of particulate matter (PM10) transfer in the vicinity of the microdistrict is reproduced. Numerical modeling is performed for the prevailing wind direction. 3D numerical simulation was carried out using the Revit software to build the CAD model of the residential area and the ANSYS software was used to perform a computational experiment. Based on the calculations, numerical data were obtained on the wind speed and on PM10 concentration fields in the residential area. Favorable and unfavorable zones of the microdistrict in terms of high concentrations of PM10 at the pedestrian zones were described.

An empirical behavioral order-driven model with price limit rules

We propose an empirical behavioral order-driven (EBOD) model with price limit rules, which consists of an order placement process and an order cancellation process. All the ingredients of the model are determined based on the empirical microscopic regularities in the order flows of stocks traded on the Shenzhen Stock Exchange. The model can reproduce the main stylized facts in real markets. Computational experiments unveil that asymmetric setting of price limits will cause the stock price to diverge exponentially when the up price limit is higher than the down price limit and to vanish vice versa. We also find that asymmetric price limits have little influence on the correlation structure of the return series and the volatility series, but cause remarkable changes in the average returns and the tail exponents of returns. Our EBOD model provides a suitable computational experiment platform for academics, market participants, and policy makers.