TECHNOSPHERE SAFETY
Introduction. The production of reinforced concrete products, being the basis of modern industrial construction, is a very significant source of dust emissions. Traditional cleaning methods are often unable to ensure the compliance with air quality requirements, and replacing them with more modern ones requires significant capital and operational costs. One of the most promising ways to solve the problem is the use of a new class of inertial dust collectors with counter swirling flows, combining constructive simplicity and low operating costs with sufficiently high work efficiency.
The aim of the work was to analyze the factors influencing the magnitude of the breakthrough coefficient of fine dust particles, as well as the development of constructive solutions aimed at reducing it.
Materials and Methods. An analytical review of technical solutions aimed at reducing the breakthrough magnitude was carried out, on the basis of which the designs of the lower input of dust collectors with counter swirling flows were developed. Methods of computational experiment and field measurements were used to confirm the effectiveness of the developed structures.
Results. By means of numerical experiments, the information about the aerodynamic flow pattern in the separation chamber of the CSF dust collector was obtained, and the breakthrough magnitude of dust particles was estimated. The solutions were developed for the design of the lower coaxial input of the swirling flow of dust collectors on the counter swirling flows, taking into account the features of dust pollution generated during the operation of technological equipment of reinforced concrete production.
Discussion and Conclusion. The presence of a displacement of the axis of the secondary swirling flow from the axis of symmetry of the separation chamber was established. The consequence of this was the non-coaxiality of the primary and secondary flows, which led to a decrease in the intensity of the twist, the formation of parasitic vortices, and, as a consequence, an increase in the value of the breakthrough coefficient. This effect was especially pronounced with a large proportion of fine dust particles, characteristic of dust pollution formed during the production of reinforced concrete products. The proposed design of the coaxial input of the secondary swirling flow reduced the magnitude of this eccentricity, which made it possible to achieve a significant reduction in the breakthrough magnitude of fine particles characteristic of dust emissions of reinforced concrete industries. The results obtained can be effectively used both in the production of reinforced concrete products and in other branches of construction production, which is characterized by intensive formation of fine dust emissions.
Introduction. With the modern active development of urban areas, the problems in the field of environmental safety are becoming increasingly relevant. These problems cannot be solved without an in-depth analysis of the factors that disrupt the ecological balance and cause negative consequences for the components of the environment. At the same time, construction industry is one of the main elements of human economic activity that forms technogenic loads. This is due, among other things, to the fact that, unlike some other areas, the pace of construction work has increased significantly over the past year. So, as of March 2023, 2,460 developer organizations were registered in the Russian Federation, which was 14 % more than in the previous period, that is, the speed and scale of construction work most of all affect the population of cities from a socio-economic point of view. At the same time, we should not forget about the environmental side of the issue. Many years of research in this area has shown the lack of a structured approach to assessing the environmental safety of urban areas, including the selection of an optimal list of environmental measures. At the same time, scientific approaches based on the ecological characteristics of the totality of natural conditions, determining the maximum permissible anthropogenic loads, identifying environmentally significant environmental parameters, such as the amount of oxygen in the atmospheric air or the availability of natural water resources, require significant time and labor costs, and also, as a rule, are not tied to specific objects of the urban environment. However, urban planning spaces, depending on their functional purpose, contain typical anthropogenic objects, among which capital construction and landscaping facilities predominate. The nature of the negative impact on the environment from such facilities is obviously also typical.
In this regard, the aim of the study was to systematize and unify numerous negative factors affecting the territory of a particular object of capital construction and landscaping, depending on the functional purpose of the territory and the types of objects located on it.
The authors propose to perform such transformations automatically within the framework of the developed online platform.
Materials and Methods. To assess the negative impact on the urban environment, it was proposed to use a methodological approach based on the concept of functional zoning of the territory. According to the Urban Planning Code of the Russian Federation, each functional zone is characterized by the presence of certain capital construction and landscaping facilities. To achieve this goal, we used methods of comparative and system analysis and generalization. Thus, the results were obtained and systematized in the work, which showed the similarity of the nature of the negative impact from the same types of capital construction and landscaping facilities.
Results. The assessment of the negative impact of capital construction and landscaping facilities on the environment was part of the research work prepared within the framework of the state program "Priority 2030". A systematic approach in analytical studies of negative factors of urban environment will allow structuring information, significantly speeding up its analysis and making appropriate decisions due to the relationships we have established between the parameters of negative factors, types of objects and functional zones in which they were located. The proposed approach was implemented within the framework of the online platform developed by the authors. At the same time, the main principle that guided us was quick access to the task of ensuring environmental safety of the territory due to accelerated automated assessment of negative factors from a given capital construction object or urban improvement.
Discussion and Conclusion. The obtained research results, which include the systematization of negative environmental impact factors on the territories of capital construction and landscaping facilities, depending on the functional zones of their location, are the basis for further development of methods for ensuring environmental safety of the urban environment. The fullest possible identification of all environmentally hazardous factors will ensure an effective assessment of the negative impact on the environment of capital construction projects and urban improvement.
Introduction. Fire-fighting water supply systems play a primary role in ensuring effective fire extinguishing. Many researchers both in our country and abroad have considered the requirements for fire-fighting water supply and problematic issues in this area. At the same time, in order to update the requirements for fire-fighting water supply, it is necessary to study the actual water consumption on fires, taking into account the characteristics of fire objects.
The aim of this research was to analyze the water consumption for outdoor firefighting depending on the characteristics of the fire object and compare the actual water consumption with the requirements of regulatory documents on fire safety.
Methods and Materials. The authors used statistical data on fires in the Russian Federation for 2019–2021 from the federal state information system "Federal Database "Fires". Methods of statistical data analysis and classification of statistical data were used to determine the actual water consumption for outdoor firefighting, depending on the class of functional fire hazard of the fire object. Visualization of the obtained results was performed by the method of graphical representation of data in the form of histograms and pie charts.
Results. The analysis showed that the highest average water consumption was required for objects of the functional fire hazard class F1.2 "hotels, dormitories (with the exception of apartment-type dormitories), dormitory buildings of sanatoriums and rest homes of general type, campsites" — 10.7 l/s. For apartment buildings, the highest average water consumption was required to extinguish fires that had arisen in the attic — 10 l/s and in the garret — 9.2 l/s.
Discussion and Conclusion. The results of the analysis can be used to clarify the requirements for water consumption for outdoor firefighting, depending on the functional fire hazard class of the object and the number of floors of buildings. In order to meet these requirements, regular monitoring of fire-fighting water supply systems is required, as well as timely maintenance and repair of external and internal fire-fighting water supply systems.
Introduction. The need to increase the level of comprehensive safety, reduce accident and injury rates, minimize the risk of failures, accidents and catastrophes determines the relevance of research on the relationship of elements of the "human–machine–environment" (H–M–E) system during open-pit mining. One of the most effective mechanisms for studying the functional characteristics of the H–M–E system of a coal mine is to conduct simulation modeling in order to identify problematic situations that trigger accidents with catastrophic consequences and injury to personnel. Simulation modeling of a technological process involves constructing a model of a real system and setting up computational experiments to describe the behavior of the system and evaluate various strategies that ensure its functioning.
The aim of the research was to adapt simulation modeling technologies to solve the problem of complex safety during open-pit mining.
Within the framework of the study, the task was to determine the elements that made the greatest contribution to the implementation of risks in the H–M–E system during stripping operations at a coal mine. The simulated subsystems were "human", "machine", "environment", and "weather conditions".
Materials and Methods. Stripping process was considered in the ARIS eEPC (extended Event Driven Process Chain) methodology as a business process linking a set of subprocesses and/or business operations. To build a simulation model in the AnyLogic software environment, the business process of stripping works in ARIS eEPC notation was described by a graph representing a structure consisting of objects and connections between them. This approach allowed us to structure the sequence of events and operations and determine alternative outcomes that arose during stripping operations.
Results. As part of the research, a method was developed for translating the formal model of the stripping business process in ARIS eEPC notation into a combined simulation model of AnyLogic. Based on the developed method, a series of machine experiments was carried out. The elements influencing the realization of the risk of accidents in the H–M–E system of a coal mine were determined.
Discussion and Conclusion. For the first time in the domestic practice of research of the H–M–E system, simulation modeling technologies have received an application for the analysis of complex safety indicators during open-pit mining. According to the simulation experiment results, it was found that the main influence on the decrease in the reliability of the "machine" subsystem was exerted by the human factor, which, together with the psychophysiological properties of a person, enhanced the development of the domino effect when implementing various types of risks. The presented results and experimental approbation of simulation modeling technology can have advanced use in the analysis of complex technical systems safety, taking into account the influence of human and man-made factors.
Introduction. A significant part of the global and state economy is the production and supply of hydrocarbon raw materials. The issues of safety in this area will remain important in the coming decades. The problem is actively discussed in the professional and scientific community. Theoretical and applied works are published. Local, point-based methods are calculated and implemented, which allow predicting and preventing emergencies in certain units of the considered objects. At the same time, there are no sufficiently justified and reproducible system solutions that can take into account the state of, for example, oil or gas field as a single complex and act as indicators not only of ordinary local accidents, but also of systemic accidents — catastrophes. Such a scientifically and experimentally based solution is described in this article. The approach is proposed as part of the formation of a comprehensive scientific and technical program (CSTP) to ensure the safety of natural and technogenic objects (NTO).
The aim of this work was to describe the practice of its application in the conditions of specific gas fields and to justify the refusal to focus on solutions that took into account only the minimum practically acceptable risk, that is, built on the ALARP principle (as low as reasonably practicable).
Materials and Methods. The article was based on the results of field tests of natural and technogenic objects (NTO) of the oil and gas complex — the Yuzhno-Russkoye field of OJSC Severneftegazprom (SNGP), LLC Gazprom Dobycha Yamburg (GDYA) and the gas pumping station (GPS) Orlovka-2 (Ukraine), conducted with the authors’ participation. Significant results were obtained and evidence-based physically interpreted during acceptance tests of an explosion-proof certified, created under the guidance of the authors of a prototype of a disaster response system (DRS) at the integrated gas treatment plant (IGTP) in LLC GDYA in 2006. At the same time, for the first time in the world practice, the fact of early detection and parrying without consequences by means of DRS on the UKPG-2 of the development of a large-scale general industrial disaster was confirmed. In the form of graphs, the revealed patterns of NTO have been visualized, which made it possible to form harbingers of the development of accidents and catastrophes at the NTO of LLC "GDYA", SNGP and GPS "Orlovka-2". Information on the high experimental reproducibility of the obtained results was presented. The technology has been developed of early detection and parrying of all types of potentially dangerous self-exciting systemic phenomena on real NTO infrastructure — self-oscillations. Three cases of their excitation in real gas fields were presented.
Results. The paper shows the fragmentary nature and locality of emergency protection systems based on the ALARP principle. The consequence of this was its complete unsuitability for early detection and counteraction to the most large-scale and costly system accidents — catastrophes that were multifactorial processes, in which none of the factors was decisive. The alternative complex solution of the problem proposed by the authors and brought to working condition was based on a system approach adapted to the NTO of the oil and gas complex. The measured parameters of various NTO infrastructure — fields of LLC "GDYA" and SNGP were processed and analyzed at the moments of development of self-oscillating modes on them, due to self-sustaining nonlinear mechanisms of interaction of NTO elements with constant (non-oscillatory) sources of energy replenishment. Three such modes of self-excitation were illustrated. The most informative in this case were the transient modes of operation of the equipment. According to the technologies experimentally developed by the authors, the areas of critical operating modes of equipment with pronounced potentially dangerous bifurcation points were analyzed. The result of superimposing treatments of the measured parameters of eight full-scale tests of NTO — graphs of dimensionless amplitude-frequency characteristics of the interconnections of a real dynamic system was presented: "input — gas cooling housing" → "output — pipe casing" at the frequency of self-oscillations.
Discussion and Conclusion. The capabilities of ALARP did not meet the tasks of system monitoring of the occurrence and development of dangerous incidents in gas fields. This conclusion can be attributed to all standard sizes of NTO infrastructure in Russia. Fundamentally different solutions should be used to ensure comprehensive observability, controllability, and safety of NTO. A comprehensive scientific and technical program is recommended: "Innovative hardware and software tools and technologies to ensure the observability, controllability, and safety of the NTO infrastructure of Russia".
Introduction. Ensuring industrial safety (IS) is one of the priority goals of any company. It is obvious that achieving its high level is impossible without the formation of a safety culture among employees, since their wrong actions can lead to emergencies and death of people at hazardous production facilities. The concept of industrial safety culture (ISC) is interpreted in different ways, but all definitions are united by the need for employees to realize that industrial safety should become their main goal and internal need. To date, there are many methods for determining the degree of ISC development. They are actively and successfully used at many enterprises. At the same time, it should be noted that the Russian legislation lacks, in particular, a methodology for quantifying the industrial safety culture specifically at the enterprises of the oil and gas complex, which have their own characteristics and specifics. Therefore, the introduction of a new quantitative approach to assessing the effectiveness of management of industrial safety culture has important scientific and practical significance on the industry agenda.
The aim of this work in this regard was to develop mechanisms to increase the ISC level at one of the gas transportation enterprises of the country based on the results of the survey of its employees.
Materials and Methods. For the analysis, the results of a three-level questionnaire conducted in 2021 and 2022 were used, which included socio-biographical characteristics of employees, their assessments on specially developed 16 components of industrial safety, as well as the interview of focus groups on six selected IS components.
Results. During the analysis of the questionnaires, an increase in the level of industrial safety culture was established from the predicted (third level) to the proactive (fourth level) according to the five-level classification of the International Association of Oil and Gas Producers (IOGP).
Discussion and Conclusions. The comparative analysis demonstrated positive dynamics of the results of the ISC level assessment by the employees of the gas transport enterprise. Its increase at this enterprise was achieved through the introduction and implementation of proactive measures, such as the development of personal obligations of employees in the field of safety, their maximum involvement in the development of competencies in the field of industrial safety, ensuring openness / transparency of communications on safety issues, and the formation of a positive attitude of employees to changes in this area.
MACHINE BUILDING
Introduction. Modern scientific and applied literature examines the problems of cable cars functioning quite thoroughly. First of all, it concerns ensuring the reliability and safety of traffic, both during operation and during project development. In addition, the paper considers the relationship of cable cars with the environment and the level of environmental load from this type of transport. A good solution could be the use of mathematical models that can take into account a set of parameters and criteria that characterize the cable car as a system. The same approach would be useful for optimizing
technical characteristics of the object. However, there is no description of such a solution in the literature. This gap is partially filled by the presented work.
The study aims to create a model of multivariable optimization of cable car technical characteristics for the transportation of municipal solid waste (MSW).
Material and Methods. To clarify the theoretical basis, the literature describing the problems of cable cars and their solutions in general has been studied. Mathematical calculations were justified by a volume of equations that proved their adequacy in determining the useful transport work, load, adjustment of time and speed of cargo movement and other significant parameters of the system under study. When forming the model, we proceeded from the principles of L. S. Pontryagin (needle variation) and Hamilton — Ostrogradsky (kinematics of a certain road segment). Text data about the features of the system elements and their interaction were summarized in tables. The main calculations results were visualized in the form of graphs.
Results. The solution to the problem of optimal control of the cable car on which solid waste was moved was presented. The motion control vector was shown as a vector of optimized technical parameters of the system: speed of movement, rope tension, number and weight of containers. The well-known solution to the optimization problem was reproduced in a general form, which involved determination of a control vector function and its corresponding trajectory with the achievement of a minimum of the target functional. The weak point of the system of differential equations for the realization of the goals of this scientific work was noted. In this regard, it was proposed to consider the investigated section of the cable car as a dynamic system with distributed parameters. The formulation of the multi-criteria optimization problem was described in detail. The advantages of reducing the number of criteria taken into account were listed and the use of the reduction method, which was based on the hierarchical structuring of the system of partial optimality criteria, was justified. Four main elements of the municipal solid waste (MSW) transportation system were considered in interrelation. This was a cable car, a transport and logistics point, a transport and logistics terminal and an environment that generated solid waste. Within the framework of this work, we considered an urbanized environment. The sub-elements of the named elements were listed and 12 directions of their interactions were shown. In detail, within the framework of a three-level hierarchy, four main complex indicators of the complexity of the system under study were described: environment, road, point and terminal. The solution of a multi-criteria optimization problem was shown, calculations were performed for the optimized parameters — the characteristic of the complexity of the road and the characteristic of the terrain. The results of calculations were presented in the form of graphs. Thus, the dependences of the optimized parameters on the weight of the loaded container, the length and speed of the cable car were illustrated.
Conclusions. The main result of the study is an idea of the possibility of a mathematical solution of a multivariable and multi-criteria problem of optimizing two characteristics of a cable car (complexity and terrain feature). The proposed approach allows you to change the hierarchy in the complex of indicators. The results of this scientific work can be used, if necessary, to integrate the road project with neural network models, to work with fuzzy linguistic indicators, to solve applied problems.
CHEMICAL TECHNOLOGIES, MATERIALS SCIENCES, METALLURGY
Introduction. Obtaining highly sensitive gas sensors is an urgent task, the solution to which will allow you to accurately and quickly assess changes in the air-gas composition of a given medium. Gas sensors based on metal-containing pyrolyzed polyacrylonitriles (Me-pPAN) are among the cheapest and most environmentally friendly gas-sensitive materials with a fast response. One of the types of sensor materials included in the Me-pPAN list is pyrolyzed polyacrylonitrile (pPAN) modified with a chromium (III) oxide molecule. The reasons for selective adsorption of pPAN and Me-pPAN to pollutant gases, which would allow controlling this process and obtaining sensory materials with increased sensitivity to gases, are not enough studied.
Therefore, the aim of this work was to establish the main causes of selective adsorption of semiconductor electrically conductive films by modeling methods in the framework of molecular and quantum mechanics.
Materials and Methods. The authors used modeling methods in the framework of molecular and quantum mechanics (MM2), the density functional theory (COSMO) method and the semi-empirical PM7 method in the MOPAC software package.
Results. MM2 and PM7 methods were used to obtain models of adsorption complexes of "Cr-pPAN – gas-pollutant" systems. Thermodynamic parameters of the system were calculated for standard environmental conditions. The dependence of the adsorption of pollutant gases on the surface of Cr-pPAN on temperature has been established.
Discussion and Conclusion. As a result of calculating the thermodynamic parameters of gas-pollutant–pPAN/Me-pPAN systems and obtaining positive values of Gibbs energies of these systems, it was confirmed that the adsorption of polluting gases on the surface of Cr-pPAN was not a spontaneous phenomenon and was effective at high temperatures. Considering that when chromium (III) oxide was introduced into the pPAN matrix, the charge on nitrogen atoms increased. It could be concluded that a chromium (III) oxide molecule had a positive effect on the semiconductor properties of pPAN. It was found that the adsorption of polluting gases (SO2 and NO2) was most likely on the surfaces of pPAN and Cr-pPAN. The results obtained in the work can be used to obtain gas-sensitive materials with specified metrological characteristics.
Introduction. At present, in scientific publications, there is no unambiguous understanding and reasoned metal physical justification of the role of the carbide phase of irradiated materials in forming the required structure and achieving a given degree of hardening of surface layers of steels during pulsed laser treatment, especially in the zone of laser hardening from a solid (austenitic) state. The solution to this issue is of great importance, since it allows us to reasonably and purposefully design the required structure of surface layers of products of various functional purposes with high performance properties. The complexity and insufficiently detailed study of the process of structure formation in the surface layers of steels under extreme thermal effects of pulsed laser radiation required a series of metal physical experiments to study the fine structure of steels after high-speed high-temperature hardening.
The aim of this article was to obtain, quantify and critically analyze the array of results of metal physical studies and to assess the degree of influence of the carbide phase on the formation of structure and properties of surface layers of steels in the process of pulsed laser hardening in different modes, that is, with and without melting the surface of the samples.
Materials and Methods. In the work, carbon and alloyed tool steels were subjected to surface laser irradiation at a Kvant 16 installation. The radiation power density was 70–200 MW/m2. Optical, scanning probe and electron microscopy were used in conducting metal physical studies, as well as methods of diffractometric, spectral and durometric analysis of steels before and after laser treatment.
Results. It was shown that laser treatment of steels with a radiation power density of 130–200 MW/m2 led to a local change in the chemical composition in the laser-fused areas of the spot, partial or complete dissolution of carbides present in the irradiated metal and an increase in the amount of residual austenite in the fused areas up to 40–60 %. It was found that on P6M5 steel, the maximum possible hardness of the irradiated zones was achieved by dissolving 30 % of carbides, on 9XC, HVG steels — 60–70 %. It was shown that under pulsed laser irradiation with q=70–125 MW/m2, that is, without melting the steel surface, "white zones" formed around carbide inclusions under the influence of thermo-deformation stresses at the boundaries of the "carbide – steel matrix" composition. They had irretrievability, dispersion of the structure and increased hardness (10–12 GPa). It was determined that the maximum hardness of laser-hardened metal in the zones of laser hardening from a solid state was achieved if the "white zones" occupied 40 % of the irradiated area of steel. It was found that the dispersion of carbides in this case was 0.5–1.5 microns.
Discussion and Conclusion. The results of the conducted studies indicate that in order to obtain the best combination of hardness and viscosity of the irradiated zones during laser treatment with melting of the surface of steels of different chemical composition, it is necessary to dissolve different amounts of carbides. The dispersed structure of laser-fused steel zones, along with a sufficiently high content of residual austenite, predetermine the possibility of improving the operational characteristics of irradiated materials, especially under conditions of external shock loads. The analysis of the conducted metal physical studies irradiated without melting the surface of steels allows us to conclude that in order to obtain a high degree of hardening, it is necessary and expedient to ensure the presence of a certain volume of dispersed carbides in the structure of the irradiated steel. The structural composition of "white zones" formed during laser treatment without melting the steel surface contributes to obtaining a unique level of operational properties. The results of the performed studies contribute to the theory of steel structure formation under conditions of extreme heat exposure and allow for a rational choice of modes of surface laser processing of products and their operability.
Introduction. The pivot assembly provides connection between the rotating and non-rotating parts of machines and mechanisms such as cranes, excavators, trailers, railway rolling stocks. In relation to rolling stock, it connects the load-carrying part of the car with the bogie and is one of the most critical and wear-out friction units. Its technical condition affects the intensity and form of wear of the surfaces themselves, the amount of resistance to rotation of the bogie when the car moves in curved sections of the track, the amplitude of the lateral rocking of the car, the intensity of wear of the wheel flanges and, as a consequence, the safety of operation of the rolling stock as a whole. Until now, periodic grease is used for this unit, which, even with a short mileage, manages to be squeezed out of the contact zones and, thereby, creates conditions for the predominance of dry friction. Until now, various proposals to solve this problem have not found application in mass production for a number of reasons, and therefore the search for ways to reduce wear in the pivot assembly of cars is still relevant. This study proposes a solution to this problem that does not require structural changes to the pivot assembly itself.
The aim of this work was to develop a technologically advanced anti-friction coating with good adhesion, which will be applied to the surface of a replaceable disk installed between the rubbing surfaces of the pivot assembly during scheduled repairs of the car chassis.
This approach will reduce the friction force and wear rate in the unit when lubrication shortage occurs due to squeezing out of the grease.
Materials and Methods. Antifriction characteristics of the developed coating was observed on a friction machine providing specific loads on the test sample up to 5000 N and a sliding speed from 0.13 m/s. The samples were examined by scanning electron microscopy (FEI Quanta 200 microscope). SEM images were acquired in a back-scattered electron (BSE) mode using a semiconductor detector. To analyze the elemental composition of beam samples, an energy dispersive spectrometer (EDAX Element EDS system) was used.
Results. A three-layer functional phosphorus-containing composite coating of the surfaces of the unit was developed, which made it possible to significantly reduce the coefficient of friction and, as a consequence, the intensity of wear of the pivot unit surface during dry friction. The optimal conditions for obtaining composite coating layers were determined. The influence of the thickness of each layer and the conditions for its production on its functional characteristics was studied.
Discussion and Conclusion. The proposed solution is manufacturable and, with appropriate adaptation, can be used to reduce wear in any open pivot assembly without radically changing its design. The methods for producing coating layers are accessible and technologically advanced for serial use.