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  • A method for improving the convergence of a single-center decomposition of a molecular orbital

    Investigation of the interaction of electromagnetic radiation with molecular systems gives most of the information about their structure and properties. Interpretation of experimental data is directly determined by the knowledge of the structure of energy levels and its change in the transition of these systems to an excited state. A key task of the methods for calculating the molecular orbitals of excited states is to accurately describe the emerging vacancies of the molecular core, leading to radial relaxation of the electron density. A method is proposed for an exact description of the electron density of a molecular system near its nuclei, which provides solutions to the problem of slow convergence of molecular orbitals in a single-center representation. The implementation of the computational procedure is examined using the example of a diatomic hydrogen fluoride molecule. The energy characteristics of the ground and ionized states of the molecule are estimated

    Keywords: single-center method, molecular orbital, excited state, ionized state, deep shell

  • Comparative analysis of recursive methods of frequency estimation

    The paper presents results of a study of operational recursive methods for quasiharmonic signals frequency estimating over a short observation interval. Such methods should be used, for example, for adaptive control of directional pattern of hydroacoustic antennas in inhomogeneous medium. We proposed recursive expressions for realizations of four methods of frequency estimation within the limits of sliding observation interval. The expressions require a minimum number of mathematical operations, which does not depend on the observation interval length. We carried out comparative analysis of the speed, accuracy, and stability of the methods. The stability of the methods was analyzed based on results of model signals processing with constant amplitude, frequency, and initial phase in presence of additive white normal noise. The accuracy was investigated by the processing results of signals with slow varying amplitude and phase. The paper also presents the results of processing of long sequences of modulated signals with additive noise within a sliding window with predetermined duration. The obtained results make it possible to select from among the four methods the optimal one according to one or more criteria.

    Keywords: communication channel, directional pattern, frequency estimation, recursive method, accuracy of method, stability of method, sliding interval

  • Monitoring of Toxic Air Contaminants in Southern Federal District

    The article presents a comprehensive analysis of emission indicators from stationary sources and emissions from motor vehicles in the Rostov region and the city of Rostov-on-Don, as well as a comparative analysis for the two regions of the Southern Federal District. The forecast of the ecological situation is made and the adequacy of the proposed mathematical model is checked.

    Keywords: emissions of pollutants, toxicity, exhaust gases, stationary sources, auto transport, internal combustion engine

  • Model for optimizing the tuning coefficients of a firmware measuring channel

    When developing large information-measuring and control systems, special attention must be paid to the interaction of various blocks of the system with each other. For example, the structure of a software-hardware measuring channel consists of four consecutively connected elements: primary converter; analog-to-digital converter; software dynamic converter; digital to analog converter. To find the parameters of the measurement channel error, mathematical models were constructed for each of the blocks. Simulation modeling of the measuring channel was carried out. As the input signal, the first-order aperiodic link model is taken. To generate the interference signal, a random number generator with a noise level of 0.5 is used. The error for the measuring channel is found. The suggested mathematical model allows to find the tuning coefficients of the software of the measuring channel, which ensure the minimum information loss in the software-hardware measuring channel. The resulting model can be used in automatic control systems for the current identification of regulator settings.

    Keywords: model of measuring channel, model of primary converter, adjustment of coefficients, error of measuring channel

  • Investigation of the possibility of controlling passenger traffic in a vehicle based on an ultrasonic distance sensor

    The work of the sensors of passenger traffic control in conditions of a dense stream of people in the controlled section of the doorway was conducted. The results showed the possibility of determining the direction of movement of a person due to a change in the distance between the sensor and the moving person. The interference due to the high density of passenger traffic, which, however, does not lead, however, to the development of the corresponding algorithms, to false alarms of the sensors is detected. However, additional field studies are required on the vehicle of the passenger counting device based on ultrasonic distance measurement sensors

    Keywords: passenger, ultrasound, passenger transport, road transport, distance sensor, Arduino, bus

  • The study of moisture condensation on the outer surface of the cladding in the winter in conditions of rapid warming

    In the period of sharp warming conditions can occur in which the temperature of the outer surface for some time will be below the ambient air temperature. While warmer ambient air, not in contact with the heated surface of the wall may cause condensation on the surface. The article discusses some of the exterior building envelope, in conditions of rapid warming and condensation process of moisture on the outer surface of the walls. With the help of finite difference method numerical modeling of the thermal regime of the outer surface.

    Keywords: Exterior walls, non-stationary conditions, moisture condensation, winter

  • The study of the distribution of temperatures in the floor heating system

    The article discusses the influence of the distance between the axes of pipes laid on the efficiency of the temperature distribution in the floor heating system. Using the computational experiment was simulated the temperature field on the surface of the floor heating. The calculations are performed using the program ELCUT.

    Keywords: underfloor heating, numerical simulation, temperature field, the temperature of the feed piping system radiant heating

  • Researches of erection of construction sites in complex engineering and geological conditions (the example of Rostov-on-Don)

    The article is devoted to the study of the location of buildings in the city of Rostov-on-Don,with considering the town-planning aspects of planning urban areas. In the process of research, a geoinformation database was created with the criteria for the location of residential buildings in various geological risk zones. As conclusions to the article, an analysis was carried out with the identification of the location of buildings in complex geological and environmental conditions within the city of Rostov-on-Don.

    Keywords: Urban construction, density of construction, engineering and geological conditions, territorial planning, geoinformation database

  • Ways of development of resource-processing enterprises of the regional investment and construction complex

    To solve the economic, technical, environmental and social problems of the region, it is expedient to create a regional inter-branch finance and construction forestry cluster (IFSLP). The creation of a regional IFSLP facilitates the most effective use of the integration process in the allocation of investment resources in the region. Cluster education allows: - to create investment attractiveness of the region; - to organize new jobs - to attract young professionals with higher education - to use innovative developments - to increase deductions to the local budget - to clean the forest from dead wood and substandard timber, to generate heat and electricity, - to create a competitive export product.

    Keywords: resource-producing complex, regional interindustry financial and construction forestry cluster, innovation, investments, forestry direction, construction materials

  • Technologies for stabilizing clay soils using nanomaterials

    The review of existing nanomaterials for stabilization of clay soils is carried out. The possibilities and limitations of the known nanotechnological approaches to the stabilization of clay soils are analyzed. The influence of nanomaterials on the physical and mechanical properties of clay soils is described.

    Keywords: soil, clay mineral, bearing capacity, soil stabilization, nanomaterial

  • Forecasting the accumulation of residual deformations in building structures

    The article deals with creep in structural mechanics. Systems of non-linear resolving equations for different types of creep kernels are written. An algorithm for solving the problem of nonlinear heredity is considered.

    Keywords: creep, nonlinear heredity, creep kernel approximations, finite elements method, exponential-type kernels, least-squares method, collocation nodes