The world's reserves of renewable energy sources are steadily declining, but the comfort of life in modern society should remain at the same level. The modern solution of the problems of thermal protection of facade systems of buildings is associated with the analysis of the specific heat capacity of the materials included in their composition. The use of new energy-efficient materials is becoming especially relevant. Such materials include vacuum thermal insulation panels, which significantly reduce heat loss in comparison with traditional thermal insulation.
Keywords: energy efficiency of buildings, thermal protection of facade systems, thermal insulation, vacuum thermal insulation panels, construction production
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 problem of a comprehensive assessment of the quality of construction production is considered. The problematic nature of such a procedure is noted, due to the fact that construction production is a multifactorial process in which a large number of material, financial and labor resources are used, with different units of measurement. It is proposed to consider the complex indicator "Integral indicator of the quality of construction production" based on the transformed Harrington desirability function, which allows taking into account many factors having different-sized controlled parameters.
Keywords: quality of construction production, integral index of construction quality, quality coefficient, generalized utility function, Harrington desirability function
The dynamic system of the grinding machine is simulated, taking into account tool wear. The purpose of the simulation is to improve the algorithmic support of an active control microprocessor device. The vibration characteristics of the SIW-5 machine ring support have been studied at idle and during processing to determine the vibration level at the moment when the grinding wheel touches the workpiece. An algorithm for maintaining the cutting speed with a decrease in the diameter of the circle due to wear has been developed and modeled. characteristics of the ring support of the SIW-5 machine at idle and during processing for the development of algorithms for controlling the grinding process.
Keywords: grinding, bearing rings, active control, mathematical model of grinding, algorithmic support
The paper presents a study of the resistance of connections of load-bearing laminated wood structures using domestic melamine-urea-formaldehyde adhesives (MMFC) to cyclic temperature and humidity influences. The method of cyclic tests is described. An assessment is made of the resistance of MMFC to temperature and humidity influences and the compliance of the selected adhesive with the requirements established for the production of long-span load-bearing structures.
Keywords: melamine-urea-formaldehyde adhesives, wooden structures, resistance of adhesive joints to cyclic temperature and humidity influences, strength
The technological process of manufacturing self-adhesive radio-absorbing materials is considered. The technological mode of manufacturing radio-absorbing materials consists of two operations – the preparation of a mixture and the production of radio-absorbing materials from the resulting mixture. An important step is mixing the mixture. The quality of the radio-absorbing material depends on the quality of the mixture.
Keywords: mixture, mixing time, scanning probe microscope, microstructure study
The paper considers the problem of the arrangement of the abutments of newly erected driveways and roads of agricultural production enterprises to existing roads and driveways. When connecting the "pies" of the roadways of the projected driveways with the existing landscaping, it is necessary to solve the problem of preventing cracking in the coating at the places of the thickness difference of the structural layers. In the article, this problem is solved both from the technical side, by ensuring the joint work of the new and existing road structure, and from the normative one by assigning the projected passage to the IVB category road, in accordance with SP 37.13330.2012, which allows the construction of a road with curbs without curbs and, as a consequence, without storm sewers and sewage treatment plants.
Keywords: road network, cadastral boundaries, the design of the widening of the passage, the technical solution of the junction of roads, transverse profile
The paper considers the opportunities and obstacles to the integration of renewable energy sources (RES) in megacities on the example of Moscow. The paper analyzes the applied RES-based generation technologies, taking into account their applicability in large cities. Special attention was paid to the conversion of unused historical dams into small hydroelectric power plants (SHPP) as an integration of RES in megacities. Based on the results of the technical and economic analysis, it was found that the conversion of an unused dam on the Yauza River into a SHPP is justified.
Keywords: small hydropower, unused dam, megacity, renewable energy integration
This article discusses the use of universal adversarial as well as to improve the effectiveness of protection systems against robots and spam. In particular, the key features that need to be taken into account to ensure an optimal level of protection against robots and spam are considered. It is also discussed why modern methods of protection are ineffective, and how the use of universal adversarial attacks can help eliminate existing shortcomings. The purpose of this article is to propose new approaches and methods of protection that can improve the effectiveness and stability of protection systems against robots and spam.
Keywords: machine learning, clustering, data recognition, library Nanonets, library Tesseract
An original approach to describe airflow in the thin conic diffusor is suggested. It is based on approximate analytic solution of continuity equation. In addition simplified model of turbulence is combined. Reliability of derived formula is confirmed by comparison with finite-element solution for designed experimental setup. The elaboration is intended to direct computer simulation of multiphase flow.
Keywords: dust-air mixture, aspiration systems, turbulence, finite element modeling, separation diffuser, digital twin
A program for computer simulation of atomization of liquid fuels has been developed. A special calibrating experiment was carried out in a gravitational field. Verification of the computer model with experimental data is carried out, the correctness of simulation modeling is determined by the convergence of the results of static generalization. Tests of a model sample of the burner device were carried out, confirming the adequacy of computer simulation.
Keywords: burner, atomization of liquid fuels, mathematical modeling, fuel jet dispersion dynamics, nozzle
The article is devoted to the consideration of topical issues related to the study of the possibility of forecasting the dynamics of stock markets based on neural network models of machine learning. The prospects of applying the neural network approach to building investment forecasts are highlighted. To solve the problem of predicting the dynamics of changes in the value of securities, the problems of training a model on data presented in the form of time series are considered and an approach to the transformation of training data is considered. The method of recursive exclusion of features is described, which is used to identify the most significant parameters that affect price changes in the stock market. An experimental comparison of a number of neural networks was carried out in order to identify the most effective approach to solving the problem of forecasting market dynamics. As a separate example, the implementation of regression based on a radial-basis neural network was considered and an assessment of the quality of the model was presented.
Keywords: stock market, forecast, daily slice, shares, neural network, machine learning, activation function, radial basis function, cross-validation, time series
The problem of quality in construction and installation works at intermediate stages is being discussed. The role of technical supervision in the construction process is outlined. A proposed indicator, the "Quality Index," is presented for consideration, which reflects not only the quality of the works but also the effectiveness of the technical supervisor's work during the construction process.
Keywords: quality, construction quality, construction quality index, quality coefficient, regulations, technical supervisor engineer
In this paper, the possibility of applying graph neural networks (NN) to study the structure of copper centers of zeolites is considered. The dataset used for NN training was prepared using the FDMNES software based on the finite difference method and included more than 2100 Cu K-XANES spectra for Cu-MOR. The performed study demonstrated the capability of graph neural networks to reproduce the Cu K-XANES spectrum corresponding to a particular model of the copper center in the zeolite framework.
Keywords: zeolite, mordenite, atomic structure, XANES, machine learning, graph neural networks
The issues of preserving existing green spaces and other elements of the natural landscape during new construction are considered. Methods for preserving perennial plantings throughout the entire course of construction are proposed. If it is impossible to save the tree at the construction site, a method of transplanting it to another place is proposed. It is proposed at the stage of design and survey work to identify healthy trees that do not grow on the site allocated for a building (structure) under construction. Then solve the problem of locating the object on the ground in such a way as to preserve healthy perennial trees as much as possible. To do this, it is necessary to carry out the removal of the object to the area, moving it as far as possible from healthy trees. The distance required to protect the tree from external influences during work is equal to the projection of the crown on the ground plus 1.5 m. At this distance, it is recommended to make stationary fences for each tree. A tree transplantation scheme and a method for calculating its weight for the selection of equipment for digging and transportation have been developed.
Keywords: landscaping, construction, tree, tree transplanting, asphalting