The article collects and structures information about the effect of chemical additives on the properties of concrete and concrete mix. The relevance of topic is due to the fragmentation of the background information and the lack of data on the study of new additives. The presentation of information in the form of a morphological table simplifies the selection of additives and reduces the risk of errors in the selection of concrete composition. Mineral additives were not considered in this article.
Keywords: construction materials, concrete, concrete mix, chemical additives, concrete properties, concrete composition, modified concrete
Electroretinography is a hightly informative method for diagnosing heterogeneous diseases associated with disorders of the vascular structures. This article describes the biomedical ophthalmic signal of an electroretinogram using wavelet analysis. The spectral characteristics of the signal, the time-frequency picture of the wavelet scalogram are estimated, and approaches to the automation of signal analysis using the available Python libraries are described. The description of the formation of wavelet scalograms of signals using the cwt function of the PyWT library has been formalized. The Gaussian wavelet of the 8th order is chosen as the basic function of the wavelet transform. In order to automate the analysis of wavelet scalograms, the sequence of determining the connectivity of segments using the connectedComponents function from the library of computer vision algorithms, image processing, and general-purpose numerical algorithms with open source OpenCV is described.
Keywords: electrophysiology, epr, electroretinogram, erg, wavelet analysis, decision support system, connected components, Otsu method, retinal dystrophy
The relevance of this study lies in the fact that the mutual influence of existing transport facilities and the newly erected underground part will be taken into account and the ways to minimize the geomechanical impact on each other will be determined. The subject of the study is the stress-strain state of the system ""structure - massif - structure"". The purpose of the study is to minimize the mutual influence of the subway, the railroad and the underground part of the designed building.
Keywords: geotechnical screen, mathematical modeling, FEM, underground structure, mutual influence, stress-strain state, subway station, minimization of influence
The transition of the construction industry to a higher level of competitiveness is due to the implementation and application of digital technologies. Traditional methods of processing incoming information are not effective for managing so much information that modern construction organizations produce. The article discusses the use of digital twins technology in the implementation of investment and construction projects. The purpose of this article is to identify the positive and negative aspects of the introduction of this technology in the activities of design and construction organizations. The main problems in the implementation of information technologies in construction organizations are analyzed. The main differences between information modeling technology and digital twins technology are presented. The advantages for the participants of investment and construction activities from the introduction of digital twins in the implementation of projects are given.
Keywords: BIM technology, digital twin, investment and construction project, digitalization
In the past few years, such objects have begun to be taken outside the city limits and rebuilt in new, undeveloped territories. And on the vacated territory, a new development begins with the intensive development of underground space. The strategic innovative approach to the implementation of projects for the development of the modern city released by the industrial territory is an urgent answer to the question of a completely new understanding of the comfortable environment, in which everything is involved: zoning of the development territory, laying new roads (city streets), underground structures and communications, transport accessibility, environmental friendliness of construction. Without understanding that the problem of forming a living space is complex, in the end, comfortable conditions of human existence will not be obtained. Various modern green building standards are based on this.
Keywords: redevelopment, green standard, BREEAM, industrial territories, industrial facilities, reconstruction, renovation, complex development of the territory, certificate
The effect of a zeolite support on the physicochemical properties of cobalt catalysts prepared by the precipitation method and calcined at 400°C was studied. The values of the specific surface of the catalysts, the degree of cobalt reduction, and the dispersion of the metal were determined, and the presence of functional groups on the surface of the catalysts was determined by BET, TPV, TPD-H2, and IR spectroscopy.
Keywords: catalyst, cobalt oxide, hydrocarbons, dispersion, active surface
A semiconductor quantum wire (QW) containing an impurity center described in the framework of a hydrogen-like model is considered. The possibility of using InSb QW in photodetectors of infrared optical radiation is discussed. The QW is modeled as a geometrically symmetric cylinder, on the axis of which an impurity center is located at an arbitrary point, with which the origin of the cylindrical coordinate system is associated, in which calculations are performed. It is assumed that the magnetic length is much smaller than the effective Bohr radius - the case of a strong magnetic field. This approximation made it possible to make the impurity potential effectively one-dimensional and obtain analytically accurate calculation results. In the effective mass approximation, in the dipole approximation, an expression is obtained for the matrix elements of the optical transitions of an electron from the impurity ground state to the size-quantized QW states for the case of transverse light polarization and the Kane dispersion law of charge carriers.
Keywords: matrix elements of optical transitions, effective mass method, quantum wire, dipole approximation, size-quantized states
The article provides an overview of construction technologies for the construction of multi-storey residential buildings, taking into account the speed of construction and the quality of structures. A summary table of various types of construction is presented, advantages and disadvantages are identified.
Keywords: construction production, optimization, constructive solution, method of construction of buildings, block, panel, large-block, monolithic frame, monolithic, modular, comparison, analysis, advantages, disadvantages
This arcticle are devoted to the modernization of housing and communal system based on the technology of "Smart Grids". The methology of developing an assessment of the effectiveness of the project of the modernization of housing and communal services facilities using the technology of "Smart Grids" is given. It from the publication that the use of "Smart Grids" technology provides energy and economic efficiency in the development of the city's energy system
Keywords: Smart grids, "Smart City", centralized heat supply systems, individual heat supply, evaluation of the economic modernization project, key performance indicators
Frameless arched coverings are one of the varieties of prefabricated structures for various needs: sports facilities, hangars for various equipment, warehouses for vegetable storage, etc. They are economical compared to other structures, since due to their light weight they do not require massive foundations, compared to frame and wall structures and can be laid with a small depth, which in turn saves on land work. Due to this, they arouse interest in their design and in the development of structural improvements, especially for conditions with a sharply continental climate with high precipitation and strong winds. In this paper, frameless arched coverings made of U-shaped profiles were considered, depending on the span of the coating and on the method of insulation for the sharply continental climate of the Republic of Khakassia. As a result, we have received that constructive solutions are required to strengthen these coatings for large spans, for example 15, 20 and 25 meters, or measures to reduce the snow load on the coating.
Keywords: frameless arched coverings, U-shaped arched profile, sharply continental climate of the Republic of Khakassia, polyurethane foam, mineral wool
The article deals with the issue of the influence of ambient temperature on the initial height of the flare emissions rise. The paper presents full-scale and theoretical studies of flare emissions operating near a temporary residential complex. In the course of the work, a series of images of flare emissions at different ambient temperature conditions was carried out and their subsequent comparison with the theoretical model was carried out. Field studies verify the theoretical model and establish that the initial height of the flare emissions depends on the ambient temperature and has an inverse proportionality.
Keywords: Flare, flare emissions, atmospheric air pollution, PM2.5
To ensure the correct and continuous operation of all electronic devices, it is necessary that all components of these devices correspond to their declared characteristics. In this article, an information-measuring system for incoming control and analysis of the quality of components is being developed. Structural and functional diagrams of the system were developed. A natural experiment was carried out.
Keywords: information-measuring system, input control, quality analysis, components
The article contains information about the factors influencing the attitude of consumers to tourist offers, and provides recommendations on the organization of an effective advertising campaign of a travel company belonging to the category of small and medium-sized businesses in the vastness of the global network.
Keywords: campaign, advertising, tourism, internet, website, direct, marketplace, query, statistics, Iran
The electrophysical and mechanical properties of a piezoceramic material based on CTS are investigated. A number of features in the behavior of the electrophysical properties of the material in the temperature range located significantly below the low-frequency (1 kHz) maximum of the dielectric constant T_m = 160℃ have been revealed. The obtained results indicate the proximity of the studied material to ferroelectric relaxors, in particular, the low coercive field E_c~5 kVcmcm, the significant dependence of T_m on the frequency and amplitude of the measuring field, as well as the behavior of the velocity of longitudinal ultrasonic waves in this ceramic. It is shown that the elastic properties of this material are very close to ferroelectric relaxors, having a high malleability in a very wide temperature range. At the same time, the squareness of the polarization loops at relatively low temperatures indicates the manifestation of the classical properties of the ferroelectric during the polarization switching processes, and not the "freezing" processes characteristic of ferroelectric relaxors. From the results obtained, it can be established that this composition will be promising for use in the actuators of adaptive optics systems and precision positioning devices due to the high values of piezomodules.
Keywords: PZT system, ferroalloy ceramics, dispersion, polarization, elastic properties, blurred phase transitions, curie temperature, depolarization temperature, ferroelectric relaxor, rhombohedral phase, tetragonal phase
The effect of a zeolite support on the physicochemical properties of cobalt catalysts was studied on a series of samples with zeolites ZSM-5, HY, and NaX. The catalysts were obtained by precipitation followed by mixing the precipitate with a zeolite support. Their properties were characterized by BET, TPR, TPD-H2, IR spectroscopy. The results of the analysis show that the type of zeolite support affects the specific surface area, reduction of deposited cobalt, and the structural properties of the active component of catalytic systems.
Keywords: precipitated catalyst, cobalt, zeolite, dispersion, specific surface area, active component, synthetic fuel, degree of reduction