The problem of flexible vibrations of a rectangular orthotorque plate clamped along the contour is considered. The general solution of the problem, which satisfies the vibartion equation identically, is constructed on the basis of the superposition method in the form of two Fourier series. Clamped boundary conditions lead to a homogeneous infinite system of linear algebraic equations with respect to unknown coefficients in the general solution. The uniqueness of a bounded non-trivial solution of an infinite system for the natural frequency is proved, the asymptotics of the unknowns are found, and an effective solution algorithm is constructed. Examples of the numerical implementation of the developed algorithm for calculating the natural frequencies and natural modes of the plate vibrations are given.

Keywords: plate, vibrations, natural frequencies, planar forces, superposition method, infinite system of linear equations, asymptotics

The construction and substantiation of a finite element model of the capillary tube running-in process, which was obtained by drawing on a fixed mandrel, are considered. The rolling rolls are cylindrical and absolutely rigid. The condition for performing the work is a comparison of the resulting gap between the pipe and the mandrel and the facet formed during deformation. The solid-state model of the process is described by an adaptive grid. Under these conditions, an informative model was obtained, which was used in parametric analysis.

Keywords: drawing with a mandrel, capillary tube, extraction, rolling, model construction, compression selection, pipe size tolerance

In the research the characteristic features of the historical appearance of the Vyritsa village on the base of its architectural and urban structure, features of the location of cultural heritage sites and precious landscape objects, on the base of which the stratеgy defining these main priorities, criteria and directions of protection of historical appearance are worked out . The concept of complex preserving of architectural and landscape environment of Vyritsa with creating of possibilities of effective using of these territories with the most display of its historical and cultural, memorial and museum potential.

Keywords: culture landscape, architectural and landscape revitalization, identity of settlement, sustainable development of the territory

In this work, an experimental model of a circuit diagram with pulsating circulation of a liquid coolant in a heated circuit of a plate heat exchanger was assembled and tested. As a result of hydraulic and energy calculations of the circuit, the optimal parameters for flow, pressure, and temperature of the coolant were selected at maximum efficiency of the impact unit. It has been established that with an increase in the operating frequency of the impact unit, the heat transfer coefficient of the heat exchanger first decreases and reaches a minimum of 452.47 W/(m2*0C) at a frequency of 0.5 Hz, and then begins to increase and reaches a maximum of 482.31 W/(m2* 0C) at a frequency of 2 Hz, after which it gradually decreases. It has also been experimentally established that the temperature at the outlet of the heat exchanger of the heated circuit increases with increasing frequency of the shock unit and reaches a maximum at a frequency of 2 Hz, after which it begins to gradually decrease. It has been established that the change in temperature at the outlet of the heat exchanger of the heated circuit exceeds the change in temperature at the outlet of the heat exchanger of the heating circuit at operating frequencies above 1 Hz, which is due to the stronger influence of cavitation at these frequencies.

Keywords: heat exchanger, heat transfer coefficient, impact unit, frequency, heat transfer

The article is devoted to the study of crowd behavior in public buildings during a fire. A method for evaluating the effectiveness of organizing the evacuation of people from a public building is proposed, which makes it possible to take into account the spread of panic among evacuees. The method is based on the development of an evacuation simulation model that takes into account the impact of certain factors on the degree of people's panic, which implements an agent-based approach. The proposed method allows, when describing the psycho-emotional behavior of each agent separately in the process of evacuation, to evaluate the effectiveness of organizing the evacuation of the crowd as a whole. The simulation results on the example of a shopping and entertainment center show that possible panic conditions of evacuees can affect the efficiency of evacuation.

Keywords: evacuation, panic, simulation model, efficiency assessment method, shopping and entertainment complex, agent-based approach

The article presents studies of a computer simulation statistical model between the characteristics of flows in terms of linear density and the proportion of components in a mixed flow. The results of evaluating the effect of the filling fraction of the component on the average and standard deviation of the fraction of the 1st component in the mixture are presented, the type of autocorrelation functions of the linear density of the mixed stream and the fraction of the 1st component in the mixed stream are determined, estimates of the spectral density of dispersion for the linear density of the mixed stream and the fraction of the 1st component in the mixed stream are shown.

Keywords: fiber mixing, linear density, component fraction, autocorrelation function, spectral density of dispersion, standard deviation

The work is aimed at modeling the control system of a slitting machine of a paper machine in order to improve the quality of products and eliminate defects in winding density. The developed automated system implements the functions of controlling the operating modes of the machine, distributing the loads of the bearing shafts, braking the roll and tensioning the paper web.

Keywords: slitting machine, paper machine, automated control system, rewinder, pressure roller, decoiler, reeler, accelerating shaft, deflecting shaft, cutting section

The article presents the results of a study of the rheological properties of cement compositions with a polycarboxylate-based plasticizer and stone flour from carbonate rocks of the Saratov region.

Keywords: cement, rheological matrix, powder-activated concrete, superplasticizer, hyperplasticizer, finely dispersed additive, stone crushing waste, stone flour, water-cement ratio, water-reducing effect

The influence of blast furnace ground granulated slag on the kinetics of strength gain of concrete prepared with a composite binder was revealed. The composite binder contained Portland cement in amounts of 70, 60 and 50%, and the rest was ground granulated slag. It has been established that at the early stage of strength development, concretes made with a composite binder have a strength lower than concrete prepared with Portland cement by 10-24%. However, at the age of 28 days, the strength of concrete using a composite binder corresponds to the strength of concrete using Portland cement. Using polycorboxylate hyperplasticizers, it was possible to obtain concrete with a W/C ratio of 0.25-0.35, which made it possible to obtain high early strength exceeding control compositions by 10-20%.

Keywords: portland cement, grn slag, grinding, composite binder, kinetics of strength gain, hyperplasticizer, kinetics of strength gain

The article is devoted to the issues of optimizing the process of technical inspection of buildings and structures damaged as a result of emergency situations, using the most modern information systems and technologies. The difficulty in carrying out work on the inspection of buildings damaged as a result of natural and man-made emergencies necessitates the search for effective organizational and technological solutions in order to reduce the time required to carry out work on the inspection of buildings and structures without losing the quality and accuracy of the studies, as well as to create safe working conditions for specialists during work.

Keywords: technical inspection, emergency situation, digital building model, ground penetrating radar sensing, information technology, geographic information technology

The article views the process of preparing territories damaged by the war for housing stock restoration and it describes the main measures that need to be carried out in the damaged neighborhoods, depending on their degree of damage. These activities in the article are divided into two groups: the first for moderately damaged quarters, and the second for severely damaged quarters. The works from the first group are somewhat different from the ones in the second. For example, the decision to restore moderately damaged quarters requires temporary strenghtning and temporary protection of damaged buildings, while in severely damaged quarters, demolition of all buildings is required. In addition, the quantity of work in the second group is larger compared to the quantity in the first due to the need to demolish all buildings, dismantle all outdoor networks and lay new ones. However, the advantages of constructing works in these quarters are that it is possible to speed up the work due to the variety of implementation methods and the equipment that can be used.

Keywords: post-conflict reconstruction, demining of territories, preparatory works, technical condition of damaged buildings

The paper presents the results of a study, the purpose of which was to automate the process of designing ventilation for a residential construction project. The ventilation system is one of the most complex life support systems of a building, which has a significant impact on the level of comfort of residents. Automation of the design of such a system will reduce the number of errors, reduce the time and labor required for design. During the study, the design process was considered as a business process consisting of individual works. When modeling this process in the “As Is” notation, the connection of the ventilation system with other engineering systems and a number of other important factors were taken into account. In the process model, the most time-consuming and, at the same time, algorithmizable works were identified. Subsequently, these works were automated using code created in the Visual Studio environment in C#. This made it possible to reduce the number of errors and reduce the time spent on creating a ventilation system project.

Keywords: automation, design, ventilation system, business process, Visual Studio

This article considers the problem of determining the temperature field near a heat-loaded source in the form of a dipole field. Solving this problem will make it possible to identify general patterns of distribution of the temperature field as one moves away from the source. This will make it possible to ensure the normal functioning of powerful electronic components by ensuring the required intensity of heat flux removal, mainly in close proximity to a heat-loaded source, that is, in the zone of maximum heat flux density.

Keywords: numerical methods, energy saving, heat engineering, thermal conditions of equipment, heat-loaded source, near zone, numerical modeling, temperature field, thermal processes, finite element method

The article considers the problem of cryptanalysis of an information security system based on a difficult-to-solve problem of Diophantine equations. A mathematical model of such a protection system is described in the article and a solution to the cryptanalysis problem using an artificial immune system adapted for solving Diophantine equations is proposed. The paper discusses the basic principles of building artificial immune systems and presents the results of experiments on evaluating the effectiveness of the proposed system of Diophantine equations of a degree not exceeding six. The results obtained demonstrate the possibility of using artificial immune systems to solve the problem of cryptanalysis of information security systems based on Diophantine equations.

Keywords: cryptanalysis, information security system, diophantine equations, artificial immune system, adaptive algorithm, efficiency assessment

This study is devoted to the development of a new mathematical model, a wedge-shaped sliding support with a non-standard elastically deformed support profile of the slider surface, taking into account nonlinear factors, under conditions of a two-layer lubricant flow, providing effective lubrication and reducing wear of the working surface. To develop this model, we will use mathematical modeling and data analysis methods to take into account all the necessary factors and parameters. To achieve this goal, well-known nonlinear equations are used: the motion of a viscous incompressible fluid for a "thin layer", the continuity equation and the Lame equation with appropriate boundary conditions, taking into account the elasticity and adaptability of the support surface of the slider, as well as equality of velocities at the interface of stratified layers, equality of pressure at the ends of the interval and equality of velocities on the surface of the guide. As a result, the main performance characteristics of the ras were identified

Keywords: nonlinear factors, elastically deformed, non-standard surface, flow of two-layer lubricant, dependence of viscosity characteristics of lubricating layers, ratio of density characteristics