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  • Local stresses in a steel beam, prestressed stretching of web

    The article deals with the case when a concentrated force is applied to the web of a prestressed beam. The preliminary shear stresses do not affect the stress state in the middle of the beam span. However, preliminary normal stresses will act over the entire height of the wall and affect the distribution of the zone of local stresses and the stress state of the web. Determination of stresses in a beam is based on the beam theory of S.P. Timoshenko. The article presents a system of equivalent forces on the edges of the wall and the equation of normal stresses in the cross section of a prestressed beam. Compared to a conventional beam, prestressing reduces normal stresses from concentrated forces.

    Keywords: thin-walled structure, steel beam, I-beam cross-section, prestressing, local stresses, local effect, Saint-Venant principle, Timoshenko SP beam theory, Karman's solution, Fourier integral, stress function

  • Development of a software product for analysis and prediction of gas concentrations in power transformers oil

    The article is devoted to the development of a software product that analyzes the concentration of gases (H2; CO; C2H4; C2H2) measured in transformer oil and set as a function of time. Product development consists of two stages. The first step is the task of classifying transformers. The second stage is predicting reliable operation before a possible failure based on the concentrations of dissolved gases in the transformer oil set as the initial data. During the development of the software product, the frameworks for creating web applications Flask and ReactJS were used, the models were trained on the frameworks H2O.ai, LightGBM, Sklearn.

    Keywords: machine learning, regression, power transformers, gas concentration, web-service

  • Modern corner joints of factory-made glued beams

    As the object of research, the angular joints of glued wooden structures used for the construction of external enclosing structures in low-rise housing construction, made in factory conditions with modern equipment, were selected. As part of the work, the available literature on this topic was analyzed. The analysis of the variability of the use of modern corner joints of external walls for low-rise construction, made of glued beams, in the design and construction, taking into account the development of technical capabilities in modern industries. Describes the old and new device technology, corner joints, indicating the advantages and disadvantages of such compounds, describes the technical characteristics of the used elements. Conclusions are drawn, as well as recommendations for the further use of these materials in design and construction.

    Keywords: glued wood, structural features of corner joints, production of wooden structures

  • On the question of the economic efficiency of a steel beam, prestressed stretching of web

    The article provides an assessment of the economic efficiency of a prestressed bistal beam, prestressed stretching of web. The comparison is made with a conventional bistal girder without prestressing with the same cross-section. The costs of material, design, production, transportation and installation are considered. It is taken into account that to create pre-stress, more labor costs are always needed, therefore, the manufacture of pre-stressed structures is more expensive than conventional structures. The purpose of prestressing is to reduce the consumption of steel in the fabrication of the structure. The structure of labor costs for the manufacture of structures is given. A comparative analysis of the cost "in business" of a running meter of a beam, prestressed by wall stretching, and a beam without prestressing, depending on the complexity of their manufacture, is carried out.

    Keywords: thin-walled structure, bistal girder, I-beam, prestressing, stretching of web, structure weight, overhead costs, labor intensity of manufacture, cost-effectiveness, custom design, value in action

  • Algorithm for optimal planning of operations to eliminate the consequences of fires and emergencies by a heterogeneous group of autonomous mobile robots

    An algorithm for planning work in a group of autonomous mobile robots performing the functions of eliminating the consequences of fires or emergency situations (ES) is proposed. Such a multi-agent robotic system (MRTS) should work effectively without the direct participation of an operator performing the functions of a decision maker (DM). The autonomy of the MRTS is due to the emergency conditions with foci of infection, dangerous for the stay of people. The paper proposes an approach and a corresponding algorithm for constructing a machine-learning model that solves the problem of optimal current planning for emergency response operations for MRTS, where an experienced decision-maker is the teacher.

    Keywords: mobile robots, work area, job distribution, limited resources, linear programming problem, optimal planning, constraints

  • Experience in modeling a load-bearing structure-the Diagrid system

    The article reproduces and supplements the experience of modeling and determining the optimal angle of inclination of the lattice with an estimate of the total lengths of the elements, the greatest forces, displacements and natural frequencies for computer models of various configurations. The possibility of using this system in civil construction with the use of volume-block technology of building construction is described. This article will be useful for design engineers involved in the design and calculation of high-rise buildings, bulk-block or modular buildings made of reinforced concrete and metal structures.

    Keywords: diagrid, mesh load-bearing structures, reinforced concrete structure, metal structures, stability, computer model, high-rise buildings, bulk-block, prefabricated module

  • Development of measures for the operation and inspection of buildings located in the permafrost zone

    Constant climate changes, the rapid pace of development of the northern and eastern territories of our country, the areas of permafrost spread, put forward a number of relevant theoretical and applied problems for science. Soil degradation in permafrost areas entails the deformation of buildings, the emergency condition of thermal and power plants, the immersion of road sections after 2-3 years of operation in the ground of the base, the failure of the supports of power supply networks, communication lines and water pipes.

    Keywords: permafrost, climate change, soil degradation, monitoring of the technical condition of buildings, operation of structures

  • Bayesian approach in justifying the number of necessary experimental measurements in environmental quality control

    Based on the Bayes approach, a representative number of experimental measurements was determined when assessing the quality of the environment, in particular, when monitoring the quality of the atmosphere and checking the compliance with the standard for the accumulation of solid municipal waste

    Keywords: Bayesian approach, quality control, experimental measurement, a priori data, a posteriori data, distribution density

  • Small-scale functional zoning as a key factor for the modern architecture of small and medium-sized industrial enterprises

    The article describes the problems of modern industrial architecture of small and medium-sized enterprises. The conflict between the established design practice based on the methodology of the 70s-80s of the XX century is revealed. A method of solving the problem based on the planning rethinking of the principle of "flexible" layouts is proposed and the introduction of a new element into the structure of the enterprise – the development zone.

    Keywords: industrial architecture, problems of modern architecture, flexible planning solutions, functional mobility, blocking of premises, small-scale functional zoning, industrial enterprise development zone

  • Automating database access for components in a Kubernetes environment

    This article describes automation of getting security-sensitive data required for database connectivity in Kubernetes environment.

    Keywords: Kubernetes, Vault, Helm, automation, security, database, Deployment, Job

  • Comprehensive assessment of structures and elements of buildings and structures as an important stage in the work on the preservation of cultural heritage objects

    This article discusses the importance of timely monitoring of the technical condition of structures and buildings in general in the process of preserving cultural heritage objects. And also, using the example of the Rostov region, the article raises one of the existing organizational and technical problems of preserving cultural heritage objects – the lack of the ability to conduct timely monitoring of the technical condition of historically significant objects in the region, and the urgent need to create local organizations to monitor the technical condition of objects and prevent violations of their operation.

    Keywords: cultural heritage object, monitoring, inspection, technical condition, complex technical studies, violations, operation, historical value, restoration, repair, preservation

  • A mathematical model and software architecture for searching encrypted data in recruiting

    The problem of searching over encrypted data using homomorphic encryption in distributed software systems is addressed. The paper considers the application of the approach developed by the authors for the implementation of a distributed system prototypes for issuing digital diplomas and certificates for obtaining competencies with recording in IPFS and an Ethereum smart contract and a search engine for recruiting personnel. The prototype of the system presented in the article demonstrates the use of homomorphic encryption, which allows the search engine and users to interact with the directly transformed data in public blockchain networks without performing the reverse transformation, ensuring their security.

    Keywords: blockchain, distributed software systems, cloud computing, homomorphic encryption, mathematical model, transactions, smart contracts, digital diploma, recruiting

  • Pulsed regeneration of cationite in a sodium-cationite filter

    In this work, an experimental model of pulsed regeneration of a sodium-cationite filter was developed. This model can work both with a stationary water flow and with a pulsed one. It is established that at a high pulse frequency, the water flow tends to a stationary one. It is found that at any frequency in a pulsed water flow, hydraulic losses will always be less than at a stationary one. At the same time, the smallest hydraulic losses are observed at a low pulse frequency of 1 Hz, and there is also a decrease in hydraulic losses in the range from 4 to 6 Hz.. It is established that at the same concentration of salt solution, the hardness of the treated water is lower in the pulsed mode than in the stationary mode. At the same time, the lowest stiffness is achieved at a low pulse frequency of 1 Hz. It is established that the time spent on regeneration at an equal inlet pressure will be longer with a pulsed water flow than with a stationary one at any frequency of pulsed regeneration.

    Keywords: cationite, water treatment, sodium-cationite filter, stationary water flow, pulse water flow, frequency, salt solution, parallel-flow regeneration, hydraulic losses, pressure

  • Software application for building the simplest emotional education of a robot that responds to sound incentives

    Currently, there are general mathematical models that allow calculating the simplest emotional education of a robot. Using these models, computer programs are implemented, for example, VibraImage by Elsys, which сalculates the simplest emotional upbringing based on the microvibrations of a person's head placed in front of a computer's webcam. However, it is not always possible to use the VibraImage program in specific situations. The purpose of this article is to describe an algorithm and software application for calculating the parameters of the simplest emotional upbringing of a robot according to the amplitude of a sound incentives acting on the robot. A formula is obtained for the simplest emotional education of a robot using the amplitude of the sound signal affecting the robot, as well as the ratio for evaluating the parameters of the simplest education of work. A computer program is described that allows one to calculate elementary education, memory coefficient and ultimate education of a robot using an audio file, which is a sound signal affecting the robot. The nature of the relationship between the parameters of the simplest upbringing and the length of the sampling step is determined. Identified the most suitable value for the sampling step length.

    Keywords: robot, education, memory coefficients, amplitude of a sound signal, mathematical model, psychology of robots, limiting education, elementary education, computer program, sampling frequency

  • Modeling and visualization of pipe bending trajectories using a MEMS sensor

    In this paper, we propose modeling and visualization of the pipe movement trajectories in a pipe bending machine. Mathematical equations for converting quaternion data to Euler angular data are presented. The paper uses the method of double integration on the acceleration data from the IMU-9250 MEMS sensor to obtain realistic speed and location. The program is implemented in the MATLAB environment for visualization of pipe trajectories in 3D representation.

    Keywords: the trajectory of the object, the device of inertial measurement, MEMS