The paper analyzes the thermal regime of a highly functional on-board control unit in an AMg6 aluminum alloy case and compares the obtained data with the thermal regime of a unit with a highly efficient heat sink made of composite materials. The calculation of the thermal field of the block was carried out using CAD tools based on the finite element method with a thermal application in order to assess its performance under given boundary conditions. Based on a comparative analysis of various heat-removing materials of the basic supporting structure, the least heat-stressed system was chosen.
Keywords: thermal regime, highly efficient heat removal, composite materials, on-board equipment, oxygen system, finite element method, mathematical model, computer-aided design system, electrical radio product, printed circuit board
When building complex technical systems, as a rule, the resources of an existing system are used as a basis, which may be redundant due to the lack of a clear definition of what the system is needed for. This necessitates the determination of the system intended purpose, the selection of elements for its construction and management in the process of its operation, aimed at achieving the intended purpose and optimizing the resource support used to build the system. The paper proposes an approach to building a system based on the development of its functioning profile, which characterizes the achievement of its intended purpose, modeling the process of a complex technical system functioning and evaluating the effectiveness of the profile. The use of the proposed methodology will allow, at the stage of building a complex system, to improve the quality and efficiency of designing a complex technical system by taking into account the functional needs of the system, as well as determining the amount of resources required to fulfill them.
Keywords: profile, complex technical system, criticality, system design, system construction, control process automation, functions, tasks, resource
The flow that occurs during the movement of an elevator cabin in the shaft of a high-rise building from the -4th to the 58th floor is considered. The moving elevator cabin works like a piston and pushes air in front of it out of the shaft and draws air into the shaft behind it. This effect is especially significant in high-rise buildings, which are characterized by a high speed of elevator cabins movement. The STAR-CCM+ software was used as a research method. To simulate the non-stationary problem of the elevator cabin movement, the technology of sliding meshes was used. It was found that when the elevator cabin moved at a speed of 7 m/s, the maximum pressure drops formed on the surfaces of the elevator shaft amounted to 130 Pa. It was found that the maximum flow rate of air entering the elevator shaft and from the elevator shaft into the hall due to the piston effect is about 250 m3/h. This value is comparable to the flow rates formed due to natural movement of air in the elevator shaft caused by stack effect in winter and cannot be automatically excluded from consideration.
Keywords: high-rise building, numerical simulation, piston effect, stack effect, elevator shaft
The reliability of assessing the amount of accumulated waste in the context of an imperfect scientific and methodological base for standardizing MSW, in the absence of generally accepted calculation methods, is not high enough. The possibility of using cluster analysis in the formation of a statistical sample of objects of a stationary trade network in setting standards for the accumulation of municipal solid waste is shown. A methodology for the formation of a representative statistical sample of objects of a stationary trading network has been developed when setting standards for the accumulation of solid municipal waste based on cluster analysis.
Keywords: waste accumulation, municipal solid waste, MSW generation standard, stationary trade network object, cluster analysis, representative sample
The problem of developing an optimal waste management system is very relevant in many countries. To solve it, it is necessary to study the processes of waste accumulation, to systematize the factors and conditions that affect the generation of waste, to determine the features of establishing waste accumulation standards for various objects. The article discusses the features of the accumulation of municipal solid waste and the establishment of standards for their accumulation for stationary objects of the distribution network.The volume and mass values of daily indicators of accumulation of MSW from a trading area of a certain type and the total value of accumulation indicators (over the entire trading area) are found. The formats of retail facilities with the maximum average daily indicators of MSW accumulation have been established. Standards for the accumulation of MSW for the category under consideration have been established for 1m2 of retail space with food products, 1m2 of retail space with non-food products.
Keywords: waste accumulation, municipal solid waste, MSW generation standard, stationary trade network object, volume indicator, mass indicators
Nowadays, the System on Chip (SoC) industry is rapidly developing. One of the objectives of SoC developers is to provide the most efficient communication between computational units. One of the possible solutions is using Networks on Chip (NoC) of various topologies with different routing algorithms. In this paper, a configurable test environment designed for cycle-accurate NoC simulation as part of a SoC, used to provide statistics about network behavior during test process, is presented. The environment is designed to evaluate NoC performance as part of a specific SoC at the development stage, when there is a full or partial RTL description of the system. The environment configuration options, its application area, general scheme and calculated NoC performance characteristics are considered. As a conclusion, an example of using the environment to evaluate the performance of a specific NoC is described in detail.
Keywords: network on chip, system on chip, performance evaluation, verification
The article discusses the process of applying a radio-absorbing coating to the surface of plastic. Vacuum plasma methods make it possible to effectively apply thin films to various surfaces. The main parameters affecting the quality and effectiveness of the properties of the applied coatings are considered.The result of the studied coatings obtained by the vacuum-plasma method showed that a sample coated with aluminum nitride, the transmission coefficient through which has not changed compared to the case of free space, is not shielding, and a sample coated with titanium metal, introducing additional attenuation of the order of 5 dB indicates the presence of absorption.
Keywords: electromagnetic radiation, thin films, application technology, radio-absorbing coating, radiation protection, magnetron.
The article discusses the design of a retaining structure in complex engineering and geological conditions, taking into account foreign and Russian regulatory requirements. The authors presented two design solutions for a retaining wall from a row of bored piles, made according to Russian and foreign regulatory prerequisites. For both construction options, the SSS parameters are determined and compared. In conclusion, it was concluded that the design of the retaining wall, made according to foreign regulatory prerequisites, turned out to be much more economical.
Keywords: retaining wall, ground anchor, calculation, protective structure, design, retaining structure, bored piles, road, stability, construction, road construction
A review of the problem of accounting for random factors in the scheduling of construction projects is considered. The problems of taking into account random factors in construction scheduling have been considered in works. However, these studies have not paid full attention to the course of construction for large projects. At the same time, scheduling problems are closely related to optimization of working hours and resource allocation in construction production. Such tasks are usually solved by considering several variants of the technological sequence of works, and the typology and variability of random factors are not fully taken into account. A number of researchers have the view that the determining factor in estimating the actual duration of construction is the reliability of suppliers and delivery of construction products. However, it is not possible to ensure the construction process in reality without interruptions in work. The main reason for this is random factors. It is suggested to take them into account on the basis of modern information technologies including artificial intelligence, stochastic approaches, probability theory and mathematical statistics.
Keywords: Construction organisation, random factors, organisational expectations, calendar modelling, stochastic search, genetic algorithms
This paper presents a simulation of the vibrations of a membrane in the form of a rhombus. Partial solutions of the problem of free vibrations of a membrane with different initial conditions are obtained and the natural frequencies of vibrations are found. The result obtained can be used to strengthen the structural elements of aircraft with a cellular diamond-shaped structure, as well as in the design of unmanned drones of the flying wing type.
Keywords: free vibrations of a membrane, a membrane in the shape of a rhombus, natural frequencies of vibrations
The problem of physical deterioration values of residential buildings for a given period of time for practical purposes is considered. A review of the existing normative and technical documents for determining the physical deterioration of residential buildings has been carried out. Various methods for predicting physical deterioration for a given period of time are considered. The conclusion is made about a linear increase in physical deterioration with an average annual increase of 1%. Recommendations are given on the use of the data obtained in the planning of operational measures for the repair and maintenance of residential buildings .
Keywords: predicting, physical deterioration, residential building, building management, average annual increase, technical inspection, chronological age method, expert method, service life, technical condition assessment
Effective reinforcement of the coating beam, by means of the construction of a framing frame around it, implies a reasonable choice of a construction from a range of rolled metal. The frame creates a single system with the coating beam by means of tension devices, the change of forces in which provides state control. In the article, a comparative analysis of moments in a frame made of an I-beam and a special steel channel, as having potentially equal performance characteristics, is proposed for a comparative study. The research was carried out on the basis of numerical modeling by the finite element method using the Etabs software product. The result of the experiment was the transverse forces and moments determined in the newly formed system – the coating beam plus the frame – from the applied loads and the percentage of reinforcement of the beam when taking into account the frame. The array of numbers obtained as a result of the numerical experiment was processed by digital mathematical analysis.
Keywords: reinforced concrete beam, I-beam reinforcement, channel reinforcement, moment, percentage of reinforcement, load, numerical method, mathematical model, comparison of results, Etabs and wxMaxima software packages
An overview of methods for assessing the state of the environment is presented. The study of methods for assessing the state of the environment and the impact of production facilities is the most important factor contributing to reducing the negative impact on the environment. An example of a comprehensive assessment of atmospheric air in the Motovilikhinsky district of Perm using the Jobs-Decon software package is considered.
Keywords: ecology, environment, subject-oriented management, production facilities, assessment, Jobs-Decon, environmental pollution
The tasks of preparing for the modernization of the automatic pressure control system with the transition from the use of a PD controller in favor of a PID controller and the introduction of a controlled electric fan drive in a boiler plant are being solved. A technique for constructing a fan model in the automatic control system for air supply to the boiler is given using the example of a VD-18 blower fan and a BKZ-160 boiler. The block diagram of the operation of the fan and pipeline is given. A mathematical model of the fan is shown, a calculation is made and a computer model is designed in MATLAB Simulink. The simulation results are presented, which prove the correctness of the obtained model. The presented model can serve as a basis for automating the air supply system in other boilers using blowers.
Keywords: automatic pressure control system, automatic control system, dynamic model, computer model, blower fan, boiler plant
This paper describes the development of a recommender system for the selection and configuration of deep neural network models. Her key area of work is evaluating the effectiveness of a neural network for a particular type of problem. The recommender system designed within the framework of the repository allows for precise search, selection and flexible configuration of neural networks depending on specific project-oriented tasks.
Keywords: recommender system, machine learning, deep learning, neural network model, expert system, neural network, repository, spatial data, geographic information system, configuration, architecture