The article considers an approach to estimating the application coefficient of standard control system equipment on a test bench. The relevance of the evaluation task at the design stage of the test bench is shown and a description of the method for solving this problem is given. The proposed approaches can be applied both at the stage of creating a test stand and when upgrading an existing positionю.
Keywords: automatic control system, test bench, analysis of the testing process, experimental testing, standard equipment, centralized control software package, application coefficient of equipment
The transitional type of pavement of highways is widespread in Russia. At the same time, the increased estimated time between repairs cannot be fully ensured by the adoption of existing design solutions for the installation of transitional pavement pavements. This is confirmed by the dynamics of changes in the operational state, presented on the example of the road of regional importance Birakan - Kuldur in the section km 0+000 - km 25+000 in the Jewish Autonomous Region. Non-failure operation during the estimated overhaul and estimated service life of the pavement is assessed by the destruction coefficient, the limit values of which are set in the regulatory documentation. A significant decrease in the pavement destruction coefficient during the first few years of operation indicates insufficient strength and stability of the transition pavement pavement, which determines the need to develop special measures to ensure them.
Keywords: road, pavement, transitional type of pavement, pavement, destruction coefficient, overhaul life, longitudinal evenness, strength
The issues of high-quality and reliable water purification for medical needs are considered. The cleaning process is inextricably linked with the automated control of engineering systems. Water for medical purposes places high demands on the degree of filtration. In this regard, the task is formulated to ensure continuous automated monitoring and control of the cleaning process. The paper shows an algorithm for controlling the process of preliminary water purification. Based on the algorithm, a program was written in the ST language, which describes the logic of the visualization with the function of displaying and controlling the process. A fragment of the functional diagram of preliminary filtering is given. A visualization of the filter washing process is presented.
Keywords: maximum level, minimum level, backup filter, storage tank, pre-cleaning, technological equipment, visualization algorithm, functional diagram, alarm, filter washing
The article analyzes the testing time of the control system on the test bench, identifies the components of the testing time, and provides the calculation procedure for a typical test bench. The results obtained can be used to estimate the time of testing control systems at the design stage of test benches.
Keywords: automatic control system, rocket and space technology, test bench, analysis of the testing process, experimental testing, testing time
The features of the functioning of steel structures in an aggressive environment are considered, the results of a qualitative and quantitative assessment of the nature of damage to a profiled sheet are given.
Keywords: steel structures, building structures, corrosion, aggressive environment, zinc coating, corrosion rate
The article deals with the problem of disposal of the sludge formed after the treatment of wastewater at the production of chemical fibers. Sludge after sedimentation is stored in storages and pollutes the environment. We carried out a comparative analysis of existing methods of disposal of sewage sludge from chemical production, which showed that the most environmentally friendly way is pyrolysis. We have analyzed the chemical and fractional composition of ash sludge after pyrolysis. The analysis revealed that the resulting ash waste is similar to ash from coal-fired power plants, which makes it possible to use it as a microfill for paving roads or sidewalks. By selling the ash waste it is possible to reduce the payback period of the pyrolysis unit installation and reduce the ecological load on the environment.
Keywords: pyrolysis, sludge, sediment, ash, disposal
The article assesses the impact of road transport on air pollution of roadside areas of a major transport highway in Volgograd. The road-car complex makes a significant contribution to air pollution by solid particles, significantly exceeding the background value. One of the criteria for assessing the impact of dust particles on the air environment according to the World Health Organization is the mass content of particles with a diameter of less than 10 microns (PM10) and 2.5 microns (PM2.5) in atmospheric air, which is normalized in the territory of the Russian Federation by hygienic standards. The fractional composition of dust particles entering the atmospheric air was assessed by the Microtrac S3500 laser particle analyzer, the concentration by the Lighthouse 3016-IAQ particle counter. The results of the dispersion analysis are presented in the form of the Rosin–Rammler–Sperling–Bennett function of the volume distribution of particles over diameters.
Keywords: dust, particle, dispersed composition, concentration, road transport, atmospheric air, transport highway
In this study, the thermal properties of porous materials with the topology of triply periodic minimal surfaces (TPMS) of Schwarz are investigated. By generalizing the results of computational experiments, the dependencies of the thermophysical properties of TPMS materials on macrostructural parameters such as size and thickness of the elementary cell have been obtained. The properties of the most common thermoplastic polymers PETG, ABS, PLA, and PHP used in additive manufacturing have been explored. It is demonstrated that the thermal conductivity coefficients of the examined TPMS materials can be represented as a linear function of the dimensionless geometric parameter – the relative thickness of the elementary cell wall. By varying this parameter, and consequently the geometric structure of the porous medium, it is possible to obtain a material with desired thermophysical properties. Verification of the obtained finite element method results is conducted based on the analysis of mesh convergence of solutions.
Keywords: effective thermal conductivity; heat transfer; porous material; porosity; thermoplastic polymer; ordered macrostructure; Schwarz minimal surface; triply periodic surface
The possibilities of a little-studied method for obtaining nanosized materials of electronic engineering with a given substructure, the zone sublimation epitaxy (ZSE) method, are discussed. In the work, it is combined with the method of gradient liquid phase epitaxy (GLE). A specific feature is mass transfer in a two-phase medium (a solid substrate and an inert gas phase acting as a transport medium) with preliminary deposition of a matrix layer formed from the melt. A feature of the sublimation process in the study was the crystallization of low-melting iron-silicon eutectic. A mathematical model of the process was proposed and compared with the experimental results. Island structures of the composition silicon (more than 90%), iron (up to 8%) and chromium (about 1.5%) have been obtained. Their parameters and size distribution were studied. A Solver-HV scanning probe microscope and a Quanta-200 scanning electron microscope were used. The study shows that the use of sublimation transfer transients makes it possible to reproducibly form doped silicon nanolayers and transform them into regular mesostructures.
Keywords: microsize growth cell method, zone sublimation epitaxy, gradient liquid phase epitaxy, island nanostructures
In the field of design and construction of transport facilities, in particular railway transport, Industry 4.0 technologies are gradually being used. In the transport industry, the concept of "digital twins" - a computer representation of a real object - has become especially widespread. The basis for "digital twins" are information models (TIM-models). At the present stage of the development of these technologies, the method of applying TIM for linear-broaching objects has not been worked out to the end. This paper considers the experience of designing railway infrastructure facilities using information modeling technologies in Russia and in the world. The concept of the methodology for the practical implementation of information modeling technology for railway infrastructure facilities at the design stage is proposed. The main limitations of the presented methodology and ways to overcome them are considered.
Keywords: BIM, information model, railways, railway information modeling technologies, information modeling methodology
One of the methods for strengthening connections in steel trusses made of cold-formed welded profiles is the use of plate overlays. This article presents their influence on increasing the strength of connections according to the criterion of bearing capacity under compression. The investigations were conducted using the component finite element method. The obtained dependencies of the increase in bearing capacity are demonstrated based on the width and angle of the brace connection. An engineering methodology has been developed to assess the strength of the reinforced connection under compression, utilizing a traditional formula from Russian design standards with the substitution of the thickness of the chord by the equivalent thickness.
Keywords: : reinforcement, connections, cold-formed profiles, bearing capacity, compression
The article analyzes the shaping of buildings and structures in modern architectural practice. Form in architecture is primarily a means of expressing and translating concepts. It's also what ultimately fills and divides the space we live in. Form in architecture can have great symbolic and cultural significance and can transform a space for the better or for the worse. The simplest of the forms are known as primary forms. The main shapes include circles, triangles and squares. Each form can be created by a combination of basic forms. When rotated or expanded, basic shapes can create three-dimensional volumes known as basic bodies. In modern architectural practice, it is very common to resort to the use of complex shapes created using spatial curves. The task of the architect is a complete visual representation of such forms in drawings, as well as using modern software graphics packages. The article raises the problem of the correct interpretation of architectural forms formed by such spatial curves (using the Hilbert curve as an example).
Keywords: architecture, spatial curves, axonometric projections, Hilbert curve, modernism, shaping, ornamentation, space
The article presents and substantiates the structure of the original combined pathospecific measuring device for the diagnosis of glaucoma, which will allow for a comprehensive analysis of the hydro- and hemodynamics of the eye and thereby improve the quality of glaucoma diagnosis. Based on this structure, a detailed metrological analysis of this installation as a means of biomedical measurements was given in the work. Brief conclusions on the work are given and prospects for the further development of the project are determined.
Keywords: combined pathospecific measuring device, tonometry, rheography, sphygmography
Prompt adjustment of the composition of the asphalt concrete mixture is key to achieving high quality asphalt concrete. To enable easy and rapid adjustment of the asphalt concrete mixture formulation, predicting the properties of asphalt concrete (Marshall stability) is critically important. There are many methods for predicting the properties of asphalt concrete, but the choice of one method or another is a very pressing problem. This article proposes two methods for forecasting Marshall stability: forecasting using a multiple linear regression model and forecasting using an autoregressive model. To evaluate the forecasting accuracy of models, we use two metrics: average absolute error (MAE) and average absolute percentage error (MAPE). The results of the study show that the autoregressive model exhibits better forecasting results, especially the second-order autoregressive model.
Keywords: asphalt concrete, control, composition adjustment, forecasting, multiple linear regression model, autoregression model, Marshall stability, forecast accuracy, mean absolute error, mean absolute percentage error
The article considered retail as a system that includes complex systems. involves consideration of a proposed system associated with multiple non-linear relationships and the presence of hidden influences. Proposed an application of the algorithm for solving a reverse problem during strategic planning in retail to help in understanding complex processes that change depending on the effectiveness of the implementation of the strategy.
Keywords: strategic planning, retail, reverse modeling perspective, fuzzy cognitive maps, management in complex systems