Overhead power line wires are affected by various external factors such as wind, ice deposits, variable temperature conditions, excessive humidity. This eventually leads to fatigue failure of the wire. It consists in the origin and slow growth of a fatigue crack. The final stage of destruction is the sudden movement of the crack at high speed. The paper proposes a model of slow crack growth, at the mouth of which there is a grain boundary. Under the influence of external stress, a section of the border is a source of vacancies. The resulting vacancy concentration gradient between the grain boundary and the free surface at the crack mouth leads to a diffusion flow of vacancies into the crack. From the solution of the diffusion problem, the magnitude of the flow and the rate of increase in the crack length are found.
Keywords: crack, grain boundary, vacancy diffusion, fatigue failure, air line, mechanical stress, vacancy flow
Vulcanization is a technological process that transforms plastic rubber into rubber. As a result of vulcanization, the shape of the product is fixed, and the material becomes more durable, hard and elastic. The purpose of the article is to determine the effect of octyl phenol-formaldehyde resin on the vulcanization parameters and to identify its optimal amount for the development of vibration-absorbing materials based on butyl rubber. The effect of a vulcanizing agent (octyl phenol formaldehyde resin) on the properties of the rubber compound during vulcanization was established. As a result of the study, the kinetics of vulcanization and the effect of various components on the properties of the rubber compound, such as elongation at break, conditional tensile strength and specific damping ability, were studied. This study is conducted in order to find the optimal rubber for placement in a seismic damper used in buildings and structures.
Keywords: vulcanizing group, vibration absorbing material, butyl rubber, rubber compound, vulcanization, octyl phenol formaldehyde resin, seismic damper
This paper considers the problem of removing noise from an image based on the discrete cosine transform (DCT) algorithm. Despite its simplicity, the algorithm is still popular in image conversion. However, recently there has been a strong development of convolutional neural networks, leaving behind “traditional” signal processing methods. In this paper, we study image denoising using DCT and convolutional neural networks and creating an interpretable convolutional neural network to obtain accurate data. The basis was the Python programming language and the library for working with neural networks – PyTorch. Based on this, a neural network model was trained on The Berkeley Segmentation Dataset. Experiments have shown that the trained neural network shows results comparable to traditional image denoising algorithms.
Keywords: noise reduction, convolutional neural network, discrete cosine transform, machine learning, signal processing, Canny operator
In accordance with the requirements of Federal Law No. 384-FZ, the safety and reliability of buildings and structures must be ensured. One of the ways to confirm the safety and reliability of building structures is to conduct field tests. The authors of this article have developed a method for full-scale testing of a reinforced concrete beam with a span of 14.52 m as part of a monolithic reinforced concrete ribbed floor. The procedure for testing the beam was drawn up with the development of measures to ensure safety during work, the adjustment of the beam testing method by loading was performed, the beam was tested by loading method with fixation of its deflections, followed by analysis of the test results. The test results showed that the developed method can be used as a full-scale test to confirm the safety and reliability of building structures, namely horizontal reinforced concrete structures.
Keywords: building structures, beam, destruction, safety, methodology, technical condition, field tests
The paper presents an algorithm for modeling production and economic characteristics for obtaining crop products, with the help of which planning problems are solved using multi-level parametric programming methods under average and unfavorable operating conditions for commodity producers. Since time series of characteristics associated with the production of products can be described by trends to assess adverse events, an algorithm for their identification was used based on the construction of multi-level trends according to the idea of the hierarchical structure of the time series. When using this algorithm, a sequence of local minima is formed from the original series, a trend is built, and levels located below this trend, called unfavorable events, are identified. The assessment of the probabilities of these events is determined by the distribution law, which describes a number of differences in actual data and trend values of a sequence of local minima. In the absence of trends and considering series of characteristics in the form of random variables, statistical and physical criteria are applicable to identify unfavorable events. As such, it is proposed to use the average value of local minima. Of the adverse events received, the smallest of them are distinguished, which represent rare events. Based on the identified events and other characteristics, the problem of optimizing the production of agricultural products is formed, the solution of which allows us to obtain optimal production volumes in accordance with maximum incomes corresponding to the calculated probability of events. A comparative analysis of planning results under average conditions and taking into account unfavorable events shows the likely losses of commodity producers at the enterprise and municipal district level.
Keywords: parametric programming, trend, adverse event, production and economic characteristics, crop production, losses, risks
The article presents a numerical simulation of energy separation (thermal stratification) in a Leontiev tube, conducted using STAR-CCM+ software. The study focuses on a comparative analysis of two different tube designs, each intended to create temperature differences in gas flows. The simulation revealed that the supersonic flow passing through the tube significantly increases in temperature at the outlet, while the subsonic flow, on the contrary, shows a noticeable decrease in temperature. Detailed profiles of gas velocity and temperature are provided for both designs, demonstrating the effectiveness of each Leontiev tube variant in creating distinct areas of gas with different temperatures without the need for additional external heat exchange. The results obtained are of practical significance for improving the efficiency of gas distribution stations, enabling more effective management of thermal flows and preventing the formation of gas hydrates, as well as for use in other technological processes where temperature separation in flows is required without external heating or cooling.
Keywords: Leontiev tube, numerical simulation, STAR-CCM+, thermal stratification, gas flow
The article deals with the peculiarities of the results of tests carried out to determine the characteristics of the contact zone organized by stamping on a steel plate. During the test, the specimen was in the steel mold in which it was manufactured. The steel form was used to prohibit horizontal movement of the steel thin plates and minimize the effect of uneven slippage of the steel gouge in the direction perpendicular to the shear force. The considered tests were carried out according to a specially developed methodology, which took into account the specifics of the contact zone shear operation, the applied tooling and took into account the set objectives of the study.
Keywords: contact zone, contact characteristics, test methodology, shear tests, stamping, composite design
The application of orthogonal matrices in information processing and transformation systems is considered. A method is proposed for assessing the results of protective masking of audio information using Walsh-structured quasi-orthogonal Mersenne matrices.
Keywords: orthogonal matrix, message masking, masking/unmasking algorithm, amplitude-frequency response, white noise, root mean square error, signal-to-noise ratio
The article discusses the method of constructing a horizontal protective screen made of large-diameter steel pipes used for the construction of tunnel-type structures using a closed method. The factors influencing the choice of this method are analyzed - features of the construction site, economic and time indicators. As an example, a project for constructing a protective screen made of large-diameter pipes for the construction of a two-section transport tunnel under railway tracks is considered. Diagrams are provided that provide basic information about the construction project, its main parameters are considered: geometric shape and dimensions, location of structural elements with an indication of their sizes. The sequence of construction work is presented, consisting of six main stages, starting with the construction of auxiliary working pits and ending with the construction of the internal structures of the tunnel. Such construction of tunnels in dense urban areas requires taking into account and minimizing their impact on existing structures and transport routes in the construction area. The article presents the results of numerical calculations of stabilized movements of the soil mass, confirming the effectiveness of this method.
Keywords: horizontal protective screens, tunnel-type structures, large-diameter pipes, soil deformations
The article presents a way to increase the load-bearing capacity of a reinforced concrete column due to metal clips from the corners with an increase in the load on it. To ensure the joint operation of the existing column and the metal cage, the corners are subjected to prestressing, which is achieved by compressing the corners with jacks.
Keywords: reinforced concrete column, column reinforcement, metal cage, prestressing of the cage
The article thoroughly explores cloud, fog, and edge computing, highlighting the distinctive features of each technology. Cloud computing provides flexibility and reliability with remote access capabilities, but encounters delays and high costs. Fog computing focuses on data processing at a low level of infrastructure, ensuring high speed and minimal delays. Edge computing shifts computations to the data source itself, eliminating delays and enhancing security. Applications of these technologies in various fields are analyzed, and their future development is predicted in the rapidly evolving world of information systems.
Keywords: cloud computing, fog computing, edge computing, cloud technologies, data processing infrastructure, scope of application, hybrid computing, Internet of Things, artificial intelligence, information systems development
This article deals with the problem of analyzing and recognizing human emotions using sound data processing. In view of the increase in the scope of application, which is largely caused by the difficult epidemiological situation in the world, the solution of the described problem is an urgent issue. The main stages are described: the audio data stream is recorded and, in accordance with the “sound fingerprinting” approach, is converted into an image that is a spectrogram of the sound data set. The stages of training a convolutional neural network on a pre-prepared set of sound data are described, and the structure of the algorithm is also described. To validate the neural network, a different set of audio data was selected, not participating in the training. As a result, graphs were constructed demonstrating the accuracy of the proposed method.
Keywords: neural network; human emotion recognition; convolutional neural network; sound fingerprinting; Tenserflow; Keras; Matlab; Deep Network Toolbox
In most countries of the world, the construction industry is one of the main sources of air pollution in urban areas and agglomerations. One of the most dangerous pollutants are fine dust particles PM2.5 and PM10, formed from the production of dusty construction processes. Due to the optimal location of administrative facilities on the construction site, it is possible to reduce the concentration of dust emissions of particles PM2.5 and PM10. In addition, the cost of the dust control method is of concern to contractors, as it leads to an increase in the cost of construction. Therefore, reducing overall transportation costs is another optimization goal. To solve several tasks at once, the study uses multi-purpose optimization using the particle swarm method (MRF) algorithm to find an optimized construction site layout that can simultaneously reduce both the level of pollution from dust emissions and transportation costs.
Keywords: environmental safety, environmental monitoring, atmospheric air protection, ecology in construction, dust suppression, feasibility study, dust collection systems, labor protection in construction
We have considered the improvement of analytical formulas for the determination of bending moments in a single-span beam with semi-rigid nodes. We have obtained analytical relationships for deflections, angles of rotation, bending moments and shear forces in a single-span beam with semi-rigid nodes. A convenient coefficient from 0 to 1 is used to specify the intermediate stiffness node. The coefficient characterizes the fraction of possible rotation of the support node. When we derived the formulas, we used the assumption of constant bending stiffness of the beam along its length and linear deformation of the beam material under load. We did not consider the cases of loading the beam with concentrated forces and concentrated bending moments in the span. We realize the complexity and necessity of calculating beams with semi-rigid nodes, so we have created a table for easy calculation. In the table you will find the values of the supporting moments depending on the degree of possible angle rotation. With the information about the bearing moments, you can load the hinged beam with them and construct a bending moment diagram. The upper left and lower left values from the table are used to determine the bending moments at the supports. The upper right and lower right values of the table are used to determine the bending moments in the beam span.
Keywords: semi-rigid nodes, multilayer structures, calculation methods, contact zone, wooden beams, reinforcement, wood, reinforcement, environmental friendliness
This paper analyzes the shortcomings of the existing organizational and technological documentation, namely the construction organization project and the project of work production. It is concluded that the main task of organizational-technological documentation is to minimize construction risks at the earliest stage, to increase knowledge about the project and to transfer the process of development and decision-making to an earlier stage of construction. As a solution to these problems, it is proposed to consider the use of building information modeling technologies (BIM) in construction, and move to the development of digital construction organization project (4D model of the construction process), which is a digital information model of the capital construction object (3D model), the elements of which are interconnected with the work on construction production. Two projects where the building information modeling technology was applied and a digital construction organization project was developed are considered: construction of an underground tunnel and reconstruction of a power unit of a combined heat and power plant. The advantages of using a digital construction organization project are proved, which makes it possible to forecast the planned duration of works, as well as the duration of works, taking into account the occurrence of risk events, necessary resources and equipment.
Keywords: digital project of construction organization, 4D model, building information modeling, project of construction organization, capital construction object