Increased concrete strength due to early loading is one of the priorities of concrete technology. Many articles contain data on changes in compressive strength after early loading. The first person to test early concrete loading was Satalkin. He tested bridge supports for static and dynamic loads. The results of his work became the basis for further research in the field of early loading of concrete. The objective of this work is to study the tensile strength in bending after early loading and to check the influence of the orientation of the samples under load. Also we considered the effect of active mineral additives on this parameter. The object of study is samples of cement-sand dough prepared on a Portland cement binder of various manufacturers. We noted a difference in the strength characteristics in bending by changing the orientation of the samples when testing them after early loading. The maximum increment of strength is noted in a plane perpendicular to the direction of compressive force. The use of a mineral additive with the replacement of a fraction of cement gave the attenuation of the observed effect.

Keywords: anisotropy of strength properties, early loading of concrete, cement composite, flexural strength, mineral additive

The types of Autonomous stationary energy-cooling systems designed for complete isolation of special objects operating without connection with the atmosphere are Considered. A technical solution is proposed that allows increasing the efficiency of the energy-cooling system, reducing the consumption of process water due to its partial recirculation for cooling the engine of an Autonomous power plant, as well as increasing the period of complete isolation of the object.

Keywords: energy-cooling system, underground facility, military infrastructure, complete isolation mode

The results of optimizing the composition of concrete based on aggregates from crushed concrete are presented. With the help of mathematical and natural modeling matched the composition of the expanding agents sulfoaluminate type, the optimal percentage of components of the modified cement required for producing a material with improved performance characteristics, the mathematical model construction and technical properties of the concrete and the kinetics of their changes to take into account the time factor and strength and weathering.

Keywords: mathematical modeling, expanding additive, factor experiment, influencing factors, level of variation, experiment planning matrix

The article deals with current methods of evaluating the organization and management in construction under conditions of uncertainty. The typology of the failure process is given, which determines the scenario of the crisis development at the enterprise. A model of forecasting and management in a crisis is proposed, and the conceptual aspects of building this model are considered. It is proposed to improve the enterprise management system based on the analysis of the economic component as a temporary function. Recommendations are given for improving the existing organizational forms of enterprise management.

Keywords: construction organization, organizational and technological solutions, reliability assessment, construction quality assessment

The article is devoted to the study of the interaction violations of electric locomotives current collectors with a contact wire, accompanied by the appearance of an electric arc. In order to further develop the system of technical diagnostics of current collection disruptions, accompanied by arcing, it is necessary to study the nature and parameters of the processes that occur with these disruptions. The main part of the article is devoted to the determination of the geometric parameters of the heating zone of the contact wire material by a movable electric arc, followed by an analysis of the applicability of the obtained dependences and their normalization. The description of the research area, the essence of the problem and the main statements of the technical diagnosis of current collection disruptions is given. The nature of the distribution of heat in the cross-section of the contact wire is shown. Based on the nature of the process and plane geometry, the parameters of the heating zone of the contact wire material are obtained: the area of the heating zone and the depth of the heating zone. Limitations in the application of the obtained dependencies are given.

Keywords: electric transport, overhead contact system, contact wire, current collection disruption, electric arc, current collection with arcing, thermal wear, softening, diagnostics

The consideration and study of the process of functioning of the offices of the company were the following objectives. Determine the quantitative dependencies of the input flow of patients and unserved requests (refusals). To conduct the sensitivity analysis. Build a basic model of a dental company as a simulation model (input model) that provides targeted variation of input parameters, and a linear programming model (output model) that processes simulation results and provides data on the degree of sensitivity of the model to changes in its parameters. Compare two simulation models of a dental company with different numbers of doctors. Determine the most effective model. Determine a combination of management variables in the optimization model that takes into account the amount of estimated lost profits due to rejection of applications, and based on this, make a conclusion about the need to hire additional employees, thereby increasing the profitability of the dental company. To achieve these goals, the following tasks were solved. A simulation model of a dental company as a Queuing system in the GPSS language was developed and studied. It is determined under which parameters the model is most effective. An analysis of the sensitivity of the model to changes in its parameters is performed. Numerical Monte Carlo methods were used to investigate this issue. We have developed a custom application in the VBA object-oriented programming language that allows you to determine for a certain period of time, starting with how many failures, you should hire an additional doctor, so that the company's profit is maximized. The practical value of the proposed model lies in its flexibility, complex nature, and consistency in the organization and technological regulation of the company's main systems and business processes. The model of a dental company has a sufficient degree of universality, as it can be used in any branch of the service sector. more complicated when you add players. The term "truel" we understand the rivalry three players. They are assigned some values of accuracy the probabilities of eliminating the opponent in one shot. At each stage of the game is chosen by the active player (the selection rule active player either randomly or by prior agreement between the players about their participation). The active player chooses an opponent to eliminate or passes the course. Developed mathematical models for different formulations of the conditions of the game (random or fixed choice of the active player). For each model are analyzed based on the probability of winning in the "truly" of accuracy, based on randomly generated program values. Comparing analytical solution and simulation, we see that they have the same answers. For large dimensions similar games analytical method requires complex calculations, so an acceptable alternative is the simulation method. Data research nahegelegenen in political and judicial practices, as well as analytical tools for the study of the theory of evolution.

Keywords: simulation model, Queuing systems, GPSS World, linear programming model, Monte Carlo numerical methods, VBA

The article is devoted to the development of a mathematical model of a vulcanization boiler, namely, the temperature control loop inside the boiler. The mathematical model of the boiler was obtained by the Rotach method in the form of a transfer function. Simulation modeling was performed in the VisSim software tool. The adequacy and stability of the model is proved and the numerical values ​​of the quality criteria of the transient process are obtained. The resulting model is intended to determine the optimal settings of the regulator of the vulcanization process control system.

Keywords: transfer function, vulcanization boiler, transient, software, system order, vulcanization process, control, calculated transfer function, delay time, sleeve

The problem of creating advanced technologies and equipment to increase the efficiency of forest regeneration by seedlings and seedlings of forest crops has not been finally solved and is an urgent task today. Of particular concern is the lack of patented equipment for the renewal of forests by seedlings and seedlings of forest crops that are competitive in the domestic and foreign markets. The purpose of the research is to prove that the basis of the search for solutions to the synthesis of patentable solutions that increase the efficiency of forest regeneration by seedlings and seedlings of forest crops can be laid the formation of a knowledge base on the basis of patent information search, and the use of a functional structural and technological analysis. In the course of the work, a classification of the main areas of patenting in the mentioned area was carried out and it was shown that the use of the proposed approach allowed the authors to develop and patent a number of new technical solutions for the equipment of forest regeneration by seedlings and seedlings of forest crops.

Keywords: forest regeneration, seedling, seedling, patent, synthesis of patentable solutions, functional-structural-technological analysis

The article deals with the dynamics of an ion beam in a tandem laser mass-reflectron. The software package that implements the mathematical model of the ion beam motion is based on the "large - particle" method.it takes into account the influence of the spatial charge field and the interaction of ions with the field of the electrodynamic system. The potential distribution in the device nodes is obtained by numerical solution of the Laplace equation using the mathematical package Freefem++, which implements the solution of partial differential equations by the finite element method. The absence of inhomogeneity of the electric field inside the reflectors is shown. A series of numerical experiments has been carried out, which has shown the convenience of using the finite element method for numerical solution of problems of electrostatics and ion optics, as well as the effectiveness of using numerical modeling to develop and optimize the parameters of mass spectrometers.

Keywords: large particle method, laser mass spectrometer, particle-particle method, electrodynamic system, Runge-Kutta method, laser plasma, ion beam, focusing system, triangulation, gas-forming impurities, time-of-flight mass spectrometer

A scheme and procedure for carrying out emanation tests of radon-protective coatings on standard concrete samples are proposed. The results of testing the material "Silor-Ultra" as an effective radon protective coating are shown.

Keywords: radioactivity, radon, radiometer, concrete, standard sample, antiradon protection, radon protection coating, radon insulation, emanation tests

The article presents the organizational and economic mechanism for increasing the investment attractiveness of the region, based on the system of investment design and implementation of investment projects, based on the complexity of the development of the region's economy, and including not only the identification of the investment potential of the region, but also the establishment of sources of capital investments; identification of directions for the development of the region, taking into account the calculations of the possible results of financial injections into these objects; creation of a phased financing plan for the taken object, the beginning of its implementation and control over it; obtaining state support for the development sector of the regional economy during the implementation of the investment project in the form of tax incentives, lower lending rates, etc.

Keywords: region, regional economy, investments, investment policy, risk, investment risks, investment portfolio, socio-economic development

The advantages of using frequency converters are well known. First of all, this is a significant energy savings due to the regulation of the rotational speed of the electric motor. In addition, ensuring a smooth frequency start using frequency converters significantly reduces thermal and mechanical loads when starting synchronous motors with a rotor excitation winding and with permanent magnets. In this paper, the start-up of a synchronous motor with a two-link frequency converter for various types of load was investigated. The following issues were considered: - creation of a three-phase two-link frequency converter model for a synchronous drive; - calculation of the torque on the shaft at rated power, as well as coefficients reflecting the nature of the load; - simulation of the start-up and operation of a synchronous motor and a two-link frequency converter with fan, conveyor and constant shaft loads. In conclusion, the model of a two-link frequency converter with a synchronous motor, which was researched in this paper, can be used in systems where the considered types of loads are used. This circuit has high energy characteristics, reliability and stability, and is also able to reduce the amplitude values ​​of currents and time of transient processes at start-up

Keywords: two-link frequency converter, permanent magnet synchronous motor, mathematical model, reliability, PSIM

This study presents the results of the development of a polymer composite material with good dielectric properties, which allows it to be used in the radio and electrical industries. This material is based on epoxy resin, polyethylene polyamine, hollow glass microspheres and gallium oxide. The use of hollow glass microspheres in the composition in an amount of 5-20 wt. h. reduces the dielectric losses, and the use of gallium (III) oxide in an amount of 5-15 wt.h. it makes it possible to increase the stability of the dielectric characteristics when working in the microwave radio range and reduce the dielectric loss. Studies have shown that a sufficiently effective composite polymer material with high physical, mechanical and dielectric properties can be obtained on the basis of the developed composition.

Keywords: composite material, epoxy resin, hollow glass microspheres, gallium oxide, permittivity, dielectric loss tangent

A model of a household refrigeration machine (BHM) is considered. The refrigerating capacity, thermal load are determined, the compressor and operational parameters are calculated, the cycle of the chiller in p-i coordinates is built.

Keywords: household refrigerator, temperature, refrigerator, heat load, cooling capacity, compressor, heat influx

This paper describes the problems of identifying effective sales channels for services working with a call center. The solution is presented in the form of a multi-level model of sales channels that works with call tracking with a limited number of phone numbers. This approach can be applied in services of small and medium-sized businesses, which cannot afford a large number of phone numbers for call tracking.

Keywords: sales channel, contextual advertising, call tracking, call center, marketing, Yandex Direct, Google AdWords