The occurrence of convection in a two-layer system consisting of a region of a free fluid and a porous array saturated with the same fluid is investigated. The equations in the Oberbeck-Bussinesq approximation are used to describe the motion of a pure fluid, and the equations based on Darcy's law are used for the porous layer. Using the shifted grid scheme, the plane problem is approximated in natural variables. At the interface, special formulas derived by the integro-interpolation method and taking into account the different types of equations in the two domains are applied. The results of calculating critical numbers corresponding to the occurrence of convection for different heights of the porous layer and Darcy numbers are presented.

Keywords: dconvection, porous medium, Oberbeck-Boussinesq equations, Darcy model, shifted grids, stability

The choice of a method for transporting hydrocarbons from the shelf of the northern seas is an urgent task, necessary for the economic justification of a project for the development of an offshore field. A comparative analysis of existing transportation schemes allows us to take into account both the advantages and disadvantages of possible options, namely, the natural and climatic features of the region, the technical capabilities of contractor organizations, the cost of field development facilities and vehicle rental.

Keywords: hydrocarbons, continental shelf, transport scheme, analysis, tanker, gas and oil pipeline, onshore infrastructure, offshore infrastructure

The article deals with the actual problematic elements of the organizational structure of enterprises in the construction of industrial buildings and structures. Using the method of optimizing the effectiveness of the existing organizational system, the necessity of introducing organizational and technological modules was revealed. An algorithm for optimizing the organizational structure of an enterprise during the construction of industrial buildings is proposed.

Keywords: optimization of organizational structures, organizational and technological modules, modules-stages, optimization algorithm

The article is devoted to the analysis of the vertical structure of the acoustic pressure field and the first-mode particle velocity in a hydroacoustic waveguide in shallow water. A waveguide consisting of a water layer with a constant sound velocity profile, a transition layer, and a half-space is considered. The acoustic properties of the transition layer are assumed to be frequency dependent. Formulas are derived that describe the vertical profile of the normal mode of a particle velocity. The transformation of the vertical profile of the first mode with increasing frequency is analyzed. The phase difference relations between the normal mode of acoustic pressure and particle velocity are analyzed. A relationship is established between the change in the vertical structure of the normal modes of pressure and particle velocity and the acoustic properties of the transition layer.

Keywords: normal modes, particle velocity, seabed, attenuation coefficient

The purpose of this work is to determine the possibility of using a fine fraction (screening) of landfill waste located on the western outskirts of Volgograd as recultivating soil. The following priority indicators were determined in the selected samples: hydrogen index (pH), the content of benz(a)pyrene, petroleum products and groups of elements related to heavy metals: mercury, cadmium, arsenic, lead, zinc, nickel and copper, namely forms extracted with acid and buffer solution and ammonium acetate with a pH of 4.5. Excess of normative values in the samples was noted for such toxicants as cadmium, nickel and copper. The value of the total indicator of chemical pollution Zc without taking into account the toxicity coefficient was 30.03, and taking into account - 46.34, which corresponds to the categories ""moderately dangerous"" and ""dangerous"". It is determined that the small fraction of landfill masses belongs to the 4th class of waste hazard - low-hazard. Direct use of sieving as a soil recultivant is not possible. It is necessary to carry out measures to detoxify it. Due to the presence of components with carcinogenic properties, acceptable detoxification directions are extraction or encapsulation of heavy metals.

Keywords: landfill masses, fine fraction, chemical pollution, hazard class

It is known that diseases of the oral cavity and anomalies of the dentition are polyetiological. Prevention of these diseases is extremely important for the health of the population of Russia, and in order to ensure maximum effectiveness of preventive programs, it is necessary to develop them taking into account all factors and taking into account the characteristics of various regions of the vast extent of the country. At the same time, the level of development of information technologies and, in particular, geographic information systems makes it relatively easy to solve such problems, which until recently required huge labor costs.

Keywords: prophylaxy, epidemiology, statistical analysis, information technology, geoinformatics

The purpose of the article is to study the material on the topic "Basalt fiber", to generalize the studied material and the accumulated experience on the given topic. The article discusses the advantages, disadvantages, problems of use and achievements in the study of basalt fiber used for the production of building materials as a reinforcing component. The analysis of the average cost of basalt fiber in comparison with other types of fiber is carried out, a conclusion is made about the advantage of using basalt fiber. General conclusions have been made about the advisability of using basalt fiber for the production of building materials, and unexplored areas of using this type of fiber have been identified.

Keywords: basalt fiber, reinforcement, stress-strain states, compression, tension, bending, shear, deformation, adhesion

The work is devoted to some questions of prosthetics of human limbs. A prototype of a prosthesis control system based on electromyography is suggested, which is not inferior to existing analogues, but significantly benefits in its cost.

Keywords: bionic prosthesis, electromyography, EMG sensor, amplifier

The possibility of using neural networks to classify the states of complex objects is considered. A software implementation of a neural network classifier is made and the results are compared with a selection algorithm based on K-nearest neighbors.

Keywords: classification, neural networks, decision making, case

The issues of joint deformation of monolithic and precast concrete in precast-monolithic structures are considered. The stages of the stress-strain state of the contact seam of the interface during its loading are determined. A method for calculating the contact seam is proposed, performed on the basis of Deryagin's binomial law of friction, and taking into account both the friction forces and the adhesion forces, as well as the inclusion of transverse reinforcement in the deformation process. Based on the works of Prof. Deryagina B. V. the application of a single "true" coefficient of friction for friction and adhesion forces is proposed. The substantiations based on experimental studies of various scientists, the possibility of applying the binomial law of friction in relation to the issues of joint deformation of monolithic and precast concrete at the 1st stage of the stress-strain state are given.

Keywords: prefabricated monolithic structures, contact seam, bearing capacity, friction, adhesion, strength, binomial law of friction, precast concrete, monolithic concrete

The article considers the content of dust particles in the filter of the split system of a residential building and in the air of an air-conditioned room, the material is taken, as well as its analysis for the content of fine dust.

Keywords: fine dust, residential air conditioning system, bacteria, integral distribution functions, "dissection"method

The article considers the issue of measuring and controlling the parameters of a high-voltage AC circuit using a Bragg grid. A model of a fiber-optic sensor based on the magnetostriction effect, the main component of which is a fiber-Bragg grating, is proposed. The 3D modeling of the magnetostriction process and the design of the block diagram are carried out.

Keywords: optical fiber, magnetostriction, bragg grid, AC, sensor, solenoid, coil, nickel, ferrite, MathCAD, COMSOL

This article discusses a proportional-integral-derivative controller circuit for an unstable system with a delay in a parallel control structure. The parallel control structure has two separate controllers for tracking tasks and suppressing load disturbances. The considered controller is developed on the basis of a direct synthesis approach by choosing a separate reference model with feedback. The proposed design method is applicable to both the lower and the high-level unstable process without model reduction in the higher order process. The effectiveness of the proposed method is demonstrated through example modeling and comparison with methods published in the literature.

Keywords: proportional-integral-derivative regulator circuit, direct synthesis, reference model, design method

A model for assessing the consumer attractiveness of commercial real estate objects is described on the example of assessing the quality of sports and entertainment centers in the city of Perm. In the course of the study, a sociological survey was conducted to identify the factors that influence the choice of consumers of a sports and entertainment center to visit. The results of the survey became the information base for the model of assessing the quality and consumer attractiveness of the studied objects. Two approaches to the definition of quality were compared – the mechanism of complex assessment and the qualimetric model.

Keywords: commercial real estate management, sports and entertainment centers, integrated assessment mechanisms, management efficiency, quality of commercial real estate, consumer attractiveness, probability of choice, decision trees, convolution matrices

In this article, the object of study is the drying of plant products in a combined drying apparatus using infrared radiation, convection and reduced pressure. The process of drying products in the food industry is still relevant today in connection with the optimization of efficiency and reduction of energy consumption. In the presented experimental study, the following products are used: apples, bell peppers, bananas. The slice thickness varies from 5 to 10 mm. Observations show that, with optimal parameters and drying modes, the possibility of using the described drying installation is fully expedient.

Keywords: drying, infrared radiation, reduced pressure, convection, dried food, pilot plant