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
This article presents the results of a research work devoted to the use of ultrafiltration membranes in the technology of purification of natural waters and wash waters of a contact clarifier unit, as well as design proposals developed on their basis for the reconstruction of existing water treatment plants.
Keywords: membrane technology, ultrafiltration, membrane module, natural water treatment technology, flushing water treatment technologywater treatment facilities, patent research
This article discusses the advantages and perspective for the use of biogas in the conditions of the Republic of Crimea. The ecological and economic aspects of the use of biogas technologies at winemaking enterprises are touched upon. Describes the methods of using biogas at the winery "Massandra" in the Republic of Crimea. The calculation of the use of natural gas in the boiler house of a winery is made. A calculation was made for the use of biogas in a boiler house. It can be concluded that when using biogas in the boiler house of a winery, fuel needs are fully covered. The surplus of the remaining fuel is proposed to be used in a cogeneration plant to generate electricity.
Keywords: biogas, cogeneration plant, grape plant residue, recycling, interchangeability, granulate, natural gas, grapes, thermal energy, electricity, winery
The article presents the results of experimental studies of crack resistance of inclined cross sections of I-shaped beams using basalt fibre reinforced bars as a transverse reinforcement . The data of previously conducted experiments were studied and the test of own samples was carried out. The beams had the same geometric characteristics and differed from each other in the angle of inclination of the transverse reinforcement, the percentage of transverse reinforcement and the shear span to depth ratio. The influence of variable parameters on the load of formation of inclined cracks and the width of their opening is analyzed. In most cases, the width of the opening of inclined cracks does not exceed the permissible values established by the codes of different countries. The exceptions were mainly samples with the lowest percentage of transverse reinforcement.
Keywords: crack resistance, I-shaped beams, transverse reinforcement, inclined cross sections, shear span, basalt fibre reinforced bars, inclined cracks
The article considers one of the ways to improve the reliability of mining equipment, by eliminating sudden failures and reducing the severity of their consequences, based on the use of digital technologies and automated control systems for its technical condition and online diagnostics. It is proposed to use the methods of diagnostics and automated control of the technical condition of power electrical machines, which consist in monitoring the current with subsequent spectral analysis of the recorded signal. The method allows to determine the current technical condition of the engine elements with sufficient accuracy. A high-performance RISC microcontroller of the AVR ATmega16 family was adopted as the constituent elements of the diagnostic complex, which contains a fast Harvard processor, program memory, data memory, input / output ports and various interface circuits.
Keywords: reliability of mining equipment, diagnostics, automated control, current monitoring, spectral analysis
As part of the proper maintenance of a number of infrastructure facilities (right-of-way for roads and railways, protected zones of power lines, gas pipeline routes, etc.), work is being carried out on their territory to remove growing unwanted vegetation. The article discusses the features of determining the values of capital investments for the formation of a system of machines, mechanisms and used mechanized and manual equipment for cleaning these territories from unwanted vegetation, shows an example of their calculation using specific brands of machines, mechanisms and equipment used in production, formulates a conclusion about the feasibility of introducing of the considered method into the production process of enterprises and organizations responsible for the maintenance of the indicated territories of linear infrastructure facilities.
Keywords: territory, unwanted vegetation, removal, mechanization, equipment, definition, capital investment
The paper considers a structural model of a solid body. Yu. N. Malashkin proposed a structural model of concrete, the main idea of which is an elementary volume in the form of a polyhedron formed from rod octahedra. When developing the model, only its analytical analysis was carried out. In this work, in the development of the model, its finite element analysis was carried out in the LIRA-SAPR software package. The study showed the coincidence of the qualitative and quantitative parameters of the model obtained by numerical and analytical calculations, confirmed its adequacy in relation to concrete.
Keywords: structural model, concrete, elementary volume, polyhedron, rod octahedron, finite element analysis, lira-sapr software package
The shear calculation scheme of a multi-storey building, popular in design practice, is considered.The application of the method of displacements is shown, when the mutual displacements of the floors of the frame are taken as unknowns. The indicated technique leads to the solution of the system of equations of the displacement method with the upper two-diagonal matrix, which makes it possible to obtain an analytical solution of the problem.
Keywords: shear calculation scheme of the building, move method, tridiagonal matrix, sweep method, reciprocal movements, analytical solution of the equation system
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 study evaluated the effect of the spring position in the panel on the amount of force required for vertical pushing of the columns. The results show that the farther the spring is from the hinge, the less pushing force is required to lift the column. In this method, the column was connected to the panel by hinged hinges at the factory, which allows lifting elements by crane as a single group during the installation of the frame structure on the construction site. In addition, a spring is installed on the panel at a certain distance, helping to push out the column and secure it. In this article, a threaded connection of precast reinforced concrete columns is proposed, which can be used to connect elements of fully assembled buildings and structures. The contact-screw connection of precast reinforced concrete consists of an upper and lower column, both have a cylindrical steel external thread in the end section connected. The strength of the screw column connection is determined by ensuring the transmission of axial loads and torque in the joints, ensuring the destruction caused by cutting and thread confusion that may occur between the connected columns. By means of the necessary calculations for the screw connection of columns made of precast reinforced concrete the corresponding rigidity and strength were confirmed. The new connections will contribute to the development of construction, its energy efficiency and acceleration of the installation process. These are effective approaches to reducing effort, time, and labor and energy costs.
Keywords: prefabricated buildings, passive assembly, column connection, screw connection, energy efficiency of installation, mounting spring, hinge loop
The geographical location, tectonic and geological-hydrogeological structure of the Maly Liman Lake basin, its landscape features as a natural monument of regional significance located on the area of the Abraus Peninsula of the Krasnodar Territory were described. The results of current bathymetry studies of the lake were shown. The hypothesis about tectonic origin of its hollow was justified. The sedimentations of the Maly Liman and Abrau lakes were tested and their description was fulfilled. By using radionuclide analysis the sedimentation rates were determined. Expedition work was carried out and a description of the outlets of the perched waters was made. The water balance development models of the of the Maly Liman Lake in the conditions of arid and relatively full-water period were constructed. The perched water dynamics of the upper reaches and surface run-off as the dominant supply sources of the lake was described. A hydrogeological section was constructed along the section of Lake Abrau – Lake Maly Liman. The existence of their hydraulic connection was proved, as well as the presence of two aquifers – the perched water and groundwater.
Keywords: Maly Liman, Limanchik, Abrau, water balance, sediment layers, bathymetry, ground waters, underground drain, mineralization, sedimentations
The work updates a strategic approach to maintaining the quality of student performance. In the article "Big Data" is presented as an approach to organizing the data obtained during the educational process. Mining analysis as a Big Data analysis tool. The authors also considered approaches to improving the effectiveness of learning, which allow predicting student performance. Blended learning, as an integration into the educational process, the best opportunities for online and distance learning, provided for the subsequent collection of Big Data for analysis. The application of data mining methods for the development of models for predicting the behavior and academic performance of students is considered. The authors propose student modeling as a key concept in data mining in education, which refers to the qualitative representation of student behavior. Algorithms for data mining are described, classification and clustering are presented as the most common tasks. The CART decision tree algorithm is presented as one of the effective data mining methods needed to predict student performance based on online activity that is stored in the Moodle LMS log file. Finally, it was concluded that the personal contact of an experienced teacher with a student in the educational process can not be replaced by the tools provided by Moodle and similar systems, but due to the growing threats caused by the pandemic, the relevance of distance education is becoming increasingly important.
Keywords: student performance quality, big data, data mining, student modeling, CART decision tree algorithm, Moodle LMS, distance education
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
This article presents one of the methods for analyzing the chirality coefficient of a medium depending on such parameters as concentration n, frequency f, dielectric constants of both the container material, the medium itself, and left- and right-handed spirals distributed in this material. As a result of this work, the frequency characteristics of the chirality coefficient were obtained at various concentrations of the container trace elements.
Keywords: chiral medium, Telledzhene element, chirality coefficient, dielectric constant of the medium, magnetic permeability of the medium, spiral structure, metamaterial substrate, bulk concentration, metamaterial, spiral inclusions
The article is devoted to the development of models and algorithms for calculating control (advisory) actions when training operators of technological processes (on the example of reloading processes and, in particular, portal cranes) on computer training complexes (CTC). A complex of models and algorithms is proposed, based on which control actions are calculated regarding discrete crane controls and the possibility of moving the load to a target position with minimization of oscillations at the end point is provided. These models and algorithms use variable parameters of the technological process, described by linguistic variables, and customizable characteristics of crane models and engines, which allows calculating control actions depending on the type of crane, the specifics of the technological process, the training methodology used for operators and other significant factors. Application of the advisory system based on the developed models and algorithms promotes to improve the training process for operators of reloading cranes at CTC and, as a result, to reduce the probability of emergency situations, reduce time and energy costs.
Keywords: computer simulator, reloading processes, portal crane, advisory system, control actions, mathematical modeling, fuzzy logic controller