The paper proposes and calculates a scheme of a two-stage gas turbine plant using carbon dioxide as a working fluid in the second stage and using heating of the CO2 circuit, as well as heating water sent for heating. As a result, the following were calculated: for the first stage turbine: parameters of fuel combustion products; air compressor parameters; fuel compressor parameters; combustion chamber parameters for a real Brayton cycle; Efficiency of the first stage turbine; for the second stage of the gas turbine: a schematic diagram was drawn up using liquid CO2 as a working fluid; calculation of CO2 parameters at key points of the Brayton cycle; the efficiency of the turbine of the second stage is calculated.

Keywords: energy efficiency, gas turbine plant, carbon dioxide, pressure, pressure ratio, combustion chamber, recuperator

In industrial production, stacker loaders used for loading and transporting goods packed on pallets are quite widely used in warehouse work. Basically, when performing a loading and transport technological operation, the functionality of the stacker is sufficient. When an obstacle appears or pallets are stacked, additional maneuverability is required, as a result of which the overall performance of the loader is lost. As a result of the conducted research, it was found that when bypassing obstacles and laying pallets, the time spent on maneuvering the chassis is up to 13%, while the utilization factor of the loader-stacker in terms of productivity is 0.7. Numerical modeling of the positioning process of the load-handling body of the loading and transport unit was carried out, on this basis, the design of a loader-stacker with expanded functionality was proposed and developed, in particular, the service area increased due to the use of a tripod manipulator and two guide actuators, which reduces the time of the technological operation of loading and unloading pallets in warehouse work. Geometrical, structural and kinematic parameters of the loader mechanism are calculated.

Keywords: numerical simulation, loader-stacker, service area, lifting body, manipulator, hinges, chassis, structural analysis, geometric analysis, kinematic analysis, executive drive, pallet

The use of information technologies in the tasks of medical rehabilitation is an effective method, but it is often complicated by the problems of using standard control devices and input into the computer by people with motor impairments. The developed hardware and software complex allows one to obtain data on the orientation of the joint in space, "turning" them into the movement of the mouse pointer, allowing one to interact with computer software, instead of the mouse manipulator. By changing the sensitivity of the sensors, the process of rehabilitation of patients is corrected. The used component base of the complex being developed and the technologies used make it possible to form a significantly lower cost, the possibility of using it outside the clinic, working without the help of specialists, application in control actions with computer software not only for rehabilitation but also for people with disabilities. The paper defines the tasks and functions that are solved by the hardware and software complex. In the 3D editor, the body frame and the internal arrangement of components are modeled, hardware and software tools are selected to ensure the implementation of the project. The functional scheme of the "Limbtracker" device has been developed. During the execution of the project, the following was implemented: reading data from sensors and writing them to a text file, filtering data by the Kalman algorithm, calibration of the device.

Keywords: hardware and software complex, home rehabilitation, neurorehabilitation, STM32, microcontroller, device design, USB-hid

The article deals with the analysis of the formation of a public center in military camps, including the analysis of towns in various military districts, as well as the estimated number of military camps.

Keywords: military camps, standard building projects, public buildings, numbers, cooperation

In connection with the development of computational complexes of the finite element method, sometimes there is a problem of choosing methods and techniques for numerical experiments with the lining of interlinear subway tunnels. The aim of this article is to consider the possibility of using one-dimensional and two-dimensional elements in modeling the lining of an underpass tunnel and the necessity of using contact elements in modeling the lining. In order to fulfill this task, two computational schemes with the lining modeled by one-dimensional elements and by two-dimensional elements have been created using the example of the existing Moscow Metro tunnel.

Keywords: finite element method, one-dimensional elements, two-dimensional elements, contact element, contact problems, tunnel, metro, mathematical modeling, stress-strain state

The paper proposes a method for automatic classification of roads based on the use of a convolutional neural network Mask-R-CNN. The developed technique makes it possible to automate the task of categorizing roads, which is fundamental in the redistribution of traffic flows, since knowledge of the category of the road allows you to determine its maximum capacity. The article contains a description of the stages of training a neural network, as well as the results obtained when using it. The method of automatic road classification proposed in the paper showed good results both in classifying roads based on satellite images and in classifying roads based on photographs of road sections. When expanding the test set, the number of classes of recognized roads can be increased to match the categories of roads according to SP 34.13330.2021. In addition, this technique (in terms of segmenting objects in photographs) can be used to control the quality of the roadway.

Keywords: road categories, convolutional neural networks, satellite imagery, image segmentation, Mask R-CNN, image recognition, computer vision

Society has always paid great attention to the problem of human behavior that does not comply with established social and generally accepted norms. Recently, interest in the problem of deviations in human behavior has increased significantly. Today, the study of deviant behavior is an interdisciplinary problem that is being solved within the framework of various scientific disciplines. Recognition of anomalies in human behavior is a complex and currently undisclosed research problem. In the process of identifying behavioral anomalies, the recognition of emotions by various signs plays a leading role. In order to increase the accuracy of the results, it makes sense to perform a comprehensive assessment of emotions on several signs at once, such as facial expression, posture, vocal signs (intonation, speech speed, etc.). The article presents existing algorithms and methods for recognizing emotions. The rationale for the choice of software product development tools is given. The functional requirements for the application are presented in the form of a diagram of use cases in UML 2.0 notation. The architecture of an Android application for recognizing anomalies in human behavior in the form of diagrams of components and classes of the conceptual level is shown. Prototypes of the user interface are demonstrated.

Keywords: abnormal behavior, algorithms and methods of emotion recognition, software architecture, functional requirements, user interface

CLT panels (English: Cross Laminated Timber) were chosen as the object of the study. This is a multilayer material made of coniferous and hard-leaved wood, which has a system of cross—glued wood in its composition. As part of the work, the available literature on this topic was analyzed, the calculation and analysis of the results obtained were carried out. The article presents the results of the calculation of the CLT panel with consideration of the possibility of isotropic and orthotropic setting of the stiffness of the panel, using elastic modules along and across the fibers. The calculation results are presented in the form of maximum deflections of the panel. Applications in the calculation of the modulus of elasticity across the fibers and taking into account orthotropic stiffness clarifies the stress-strain state of the overlap panel. Based on the calculations performed and the analysis of the results obtained, conclusions are drawn.

Keywords: CLT-panel, transverse bending, modulus of elasticity, stiffness, stress, deflection, orthotropy

The problem of choosing the desired image segmentation algorithm and its real-time implementation arises in systems that work with a high-speed video data stream. Labeling related areas is an important step in preparing images for neural network training set. In this paper a modified one-pass image labeling algorithm for use in field-programmable gate arrays (FPGAs), as well as its implementation using the Xilinx System Generator for DSP and the Matlab/Simulink package was proposed. The results of the algorithm operation on test images, as well as images obtained experimentally, are presented. This algorithm was developed to analyze and evaluate the quality of wheat seeds by classifying their images using artificial intelligence.

Keywords: labeling of related areas, artificial intelligence, segmentation, stream processing

The study is devoted to the generalization of the existing world experience on the impact of recycled polyethylene terephthalate (PET) products when they are added to concrete on its characteristics. Analysis of the available data shows the effectiveness of the use of PET fiber in a concrete matrix in order to recycle plastic waste, facilitate concrete structures, save cement consumption and improve the strength characteristics of concrete. But the researchers did not come to a consensus on the effective consumption of fiber during reinforcement, the influence of the shape of the fibers used on the properties of fiber concrete, as well as the areas of application of this material.

Keywords: concrete, concrete matrix, fiber, dispersed reinforcement, polyethylene terephthalate, tensile strength, compressive strength

This article contains the results of a study of the strength characteristics of building mortars of various compositions based on magnesia binder (magnesia oxychloride cement). The results obtained: the final compressive strength (28-day) within the studied compositions is from 12 to 45 MPa, the kinetics (rate) of strength growth on the first day of hardening is from 22 to 38%, on the third day of hardening – 33-68%, on the seventh day – from 50-88%, and about 120% from the design (28-day) with further hardening.

Keywords: magnesia oxychloride cement, magnesia binder, magnesia mortar, magnesia concrete, caustic magnesite, magnesium chloride, compressive strength, strength set kinetics

A periodic semiconductor structure is considered, consisting of tunnel-uncoupled quantum wires (QW) based on InSb containing impurity centers. The uniform magnetic field is directed along the QW axis. For the case of light polarization transverse with respect to the QW axis in the framework of the dipole approximation, in the effective mass approximation, an analytical expression for the impurity absorption coefficient of light is obtained taking into account the dispersion of the QW radius described by the Gauss function. It is shown that on the spectral curve constructed in the Maple program, for given parameters of the QW and the semiconductor structure, there is a sequence of resonant maxima with a doublet structure. The cyclotron frequency determines the distance between the maxima in the doublet, and the frequency of the doublets on the spectral curve is determined by the hybrid frequency. With an increase in the magnetic field, the dynamics of the edge of the impurity absorption band is observed, which can be used to create detectors of optical radiation in a wide range of wavelengths and will make it possible to identify such semiconductor structures. It is also possible to obtain valuable information about the parameters of the QW and the band structure of the semiconductor from the spectral curve

Keywords: impurity absorption coefficient, quantum wire, low-dimensional semiconductor structures, impurity center

The paper studies the problems of heat transfer intensification in shell-and-tube heat exchangers used in the heat supply of buildings. The solution to this problem is to use the circulation of the coolant flow in a pulsed mode, with different frequency pulsations. Based on experimental studies to determine the efficiency of a shell-and-tube water-to-water heat exchanger, a method has been proposed, in accordance with which it has been proved that the pulsed mode, compared to the stationary one, is the most effective in terms of key indicators, such as the heat transfer coefficient and thermal power.

Keywords: intensification, heat transfer, heat exchanger, coolant, fluctuations, efficiency, thermal power

The article presents the results of computational studies that are part of the authors' comprehensive research on the development of a methodology for predicting the resistance of steel fiber concrete to thermal effects at NPP facilities with various parameters of dispersed reinforcement. The studies were carried out using selected models to describe the processes of thermal deformations and changes in the most important properties of steel fiber based on previously obtained experimental and calculated data on thermal changes of steel fiber on an optimized cement-sand matrix with five types of steel fiber with a volume content of 0.5% to 6% after heating at 110-1100 oC. Based on calculations in accordance with the accepted hypothesis and the selected models, the dependences of thermal changes in the properties of steel fiber concrete relative to matrix changes from the calculated changes in linear dimensions due to the formation of cracks in the fiber concrete are established. The dependences of thermal changes in the linear dimensions of steel fiber concrete due to the formation of cracks on the ratio of the calculated unreliaxed tensile structural stresses in the matrix to the tensile strength of the matrix are established. Based on the performed studies, a method for predicting thermal deformations, changes in mass, linear dimensions due to the formation of cracks, strength, water resistance of steel fiber concrete, based on thermal deformations and changes in the properties of the matrix, parameters of dispersed reinforcement is formulated.

Keywords: steel fiber concrete, prediction of resistance to thermal effects, cracking, thermal changes in linear dimensions and properties

The article collects and structures information about the effect of chemical additives on the properties of concrete and concrete mix. The relevance of topic is due to the fragmentation of the background information and the lack of data on the study of new additives. The presentation of information in the form of a morphological table simplifies the selection of additives and reduces the risk of errors in the selection of concrete composition. Mineral additives were not considered in this article.

Keywords: construction materials, concrete, concrete mix, chemical additives, concrete properties, concrete composition, modified concrete