Operating Zones Research Articles

A new solution approach for non-convex combined heat and power economic dispatch problem considering power loss

The combined heat and power economic dispatch (CHPED) problem is a non-convex multivariate global optimization problem. The objective of the problem is to reduce total production costs while imposing a variety of constraints and meeting the demand for power and heat. Three recently presented metaheuristic approaches, Slime Mould Algorithm (SMA), COOT algorithm and Marine Predators Algorithm (MPA), are applied for solving CHPED problem. Studies dealing with the CHPED problem in the literature often do not consider valve points effect, prohibited operation zones for power-only units, feasible region constraints of combined heat and power units, all at once. Furthermore, power losses are neglected especially in large-scale problems. In this study, the CHPED problem is solved by considering all operational constraints including active power transmission losses. Three separate case studies with dimensions of 11 units, 48 units, and 96 units were used in the tests under various limitations. The experimental results revealed that MPA outperformed not only SMA, and COOT but also the algorithms proposed previously in the literature.

Эффективность насоса системы подачи смазочно-охлаждающей жидкости

Cooling and lubrication are the most important processes in such operations as the metal workpiece cutting, drilling and grinding. It becomes necessary in machining a workpiece to supply the lubricating and cooling fluids to the tool operation zone in the required amount, which is provided by the pump and the connecting pipeline. Pump operation essentially depends on properties of the lubricating and cooling fluid, in particular, on its viscosity affecting the flow, pressure and energy costs. The paper propose an algorithm for determining the pump hydraulic characteristics, when supplying the lubricating and cooling fluid. As an example, the submersible vertical centrifugal pumps were considered designed for using in the machines cooling systems and systems supplying the lubricating and cooling fluid. Empirical dependences are presented of the pump head, consumed power, efficiency and indicator of the specific energy cost on the water supply. The obtained dependences were recalculated for the pump operating conditions with liquids, which viscosity was much higher than that of water. It is shown that viscosity significantly changes the pump characteristics during its operation in the network.

Работа учебного отдела Московского территориального научно-практического центра медицины катастроф Департамента здравоохранения г.Москвы в режиме повышенной готовности в условиях проведения Специальной военной операции

Summary. The work of the training department of the Moscow Territorial Scientific and Practical Center for Disaster Medicine of Moscow Health Care Department on first aid training courses under conditions of a special military operation is presented. The importance of forming stable first aid skills in the combat operations zone was shown. The question about the need to expand the list of first aid measures in the area of special military operation is raised; the question about the need to revisie and to expand the first aid training program is raised.

Progress in grinding performance by additive manufacturing of grinding wheels integrated with internal venturi cooling channels and surface slots

Among the most promising features of additive manufacturing are tool or form-free manufacturing and the ability to create intricate geometries that are difficult or even impossible to fabricate with traditional methods. These advantages can be employed to produce enhanced grinding tools. Efficient coolant fluid delivery into the cutting zone of the grinding operation has been a challenging problem since high frictional contact in the arc zone deteriorates the resin bond and lessens the grinding performance. This research study was dedicated to assessing the influence of internal cooling along with surface structures on the grinding performance of resin-bonded grinding wheels fabricated via additive manufacturing. This research introduced a novel structure that benefits from internal venturi shape cooling channels to provide exceptional fluid velocity in the tool and workpiece interaction zone. The grinding wheels have been produced employing vat photopolymerization. Grinding experiments with and without internal cooling were conducted on an aluminium plate to study the impact of introduced structures on the main aspects of grinding performance, such as cutting forces, surface roughness, tool wear, and dimensional accuracy. Two different grinding scenarios comprising shallow (10 μm depth of cut) and deep grinding (100 μm depth of cut) were carried out to reveal the influence of the material removal rate on the grinding experiments. The measured grinding forces revealed that integrating internal cooling channels and surface slots in a grinding tool could significantly reduce the grinding forces, which was more pronounced in the case of using venturi channels. Measured tool wear and dimensional accuracy together with calculated grinding ratio revealed that using cooling channels could participate in a notable increase in tool life and material removal ability, especially for venturi channels, due to improved cutting conditions, by which higher dimensional accuracy was obtained as well for the ground parts. Besides, it was discovered that the cooling channels could improve the surface quality of the ground part, which was less noticeable with the venturi channel grinding wheel. Furthermore, the optical and confocal microscopy detection confirmed that internal cooling channels could reduce chip loading on the grinding wheel surface, decrease the required number of dressing intervals, and cause effective promotion of tool life.

A nondominated sorting genetic algorithm III with three crossover strategies for the combined heat and power dynamic economic emission dispatch with or without prohibited operating zones

This paper presents a nondominated sorting genetic algorithm III with three crossover strategies (NSGA-III-TCS) for the combined heat and power dynamic economic emission dispatch (CHPDEED) problems with or without prohibited operating zones. The first strategy updates the individuals of the first nondomination rank by a modified improvisation of the harmony search algorithm, which accelerates the information exchanges of the elite individuals. The second strategy regulates the individuals of the last nondomination rank according to a modified single-point crossover of the genetic algorithm, which strengthens the convergence of the population. The third strategy adjusts the remaining individuals in terms of a modified DE/rand-to-best/1 mutation of the differential evolution algorithm, and it guides these individuals to move towards the ones which have at least one minimum objective function value, which is beneficial for expanding the distribution range of the population. NSGA-III-TCS obtains the largest average hypervolumes and shows a desirable convergence for six CHPDEED problems. NSGA-III-TCS achieves relatively high coverage rates in most cases, indicating the dominance of the Pareto sets of NSGA-III-TCS over those of the other algorithms. Also, it has relatively low average spacings for all problems, suggesting the good evenness of the Pareto sets.

Metaheuristic Framework for Material Screening and Operating Optimization of Adsorption-Based Heat Pumps.

The current methods applied to material screening for adsorption-based heat pumps are based on a fixed set of temperatures or their independent variation, providing a limited, insufficient, and unpractical evaluation of different adsorbents. This work proposes a novel strategy for the simultaneous optimization and material screening in the design of adsorption heat pumps by implementing a meta-heuristic approach, particle swarm optimization (PSO). The proposed framework can effectively evaluate variable and broad operation temperature intervals to search for viable zones of operation for multiple adsorbents at once. The criteria for selecting the adequate material were the maximum performance and the minimum heat supply cost, which were considered the objective functions of the PSO algorithm. First, the performance was assessed individually, followed by a single-objective approximation of the multi-objective problem. Next, a multi-objective approach was also adopted. With the results generated during the optimization, it was possible to find which adsorbents and temperature sets were the most suitable according to the main objective of the operation. The Fisher-Snedecor test was applied to expand the results obtained during PSO application and a feasible operating region built around the optima, enabling the arrangement of close-to-optima data into practical design and control tools. This approach allowed for a fast and intuitive evaluation of multiple design and operation variables.

LIDAR MEASUREMENTS OF METHANE CONCENTRATION IN OIL AND GAS PRODUCTION REGIONS BY PLATFORM METHOD

The issues of carrying out lidar measurements of methane concentration in oil production platform operation zones are analyzed. The issue of lidar re-calibration during methane measurements in the areas of oil platform operation zones in wind conditions is considered. It is noted that due to the low efficiency of gas flares, part of the methane does not burn and spreads in the atmosphere by wind. It is noted that in the presence of a headwind towards the meter, an increase in the concentration of not only methane, but also aerosol is observed. In this case, it becomes necessary to re-calibrate lidar for aerosol using the corresponding solar photometer readings.

Report on the work of the chief pediatric surgeon of the Ministry of Health of the Russian Federation in 2022

This editorial presents a report on the work of the Chief Pediatric Surgeon of the Ministry of Health of Russia for 2022. From the very beginning of his activity, he established regular interaction with the chief supernumerary pediatric surgeons and executive and legislative authorities of the regions of the Russian Federation, both remotely and by visiting surgical clinics in 15 cities. To prepare a program for the creation of interregional centers for specialized surgical care in the most popular medical specialties, much attention was given to the improvement of pediatric surgical care in the Far East with repeated trips to this region. As a result of the joint work with leading specialists of the Russian Association of Pediatric Surgeons and chief pediatric surgeons of the Russian Federation, the first Regulations on Interregional Centers for Neonatal Surgery was created. Chief pediatric surgeons organized surgical care for children in the special military operation zone and border regions with business trips to Taganrog, Rostov-on-Don, and Lugansk. Throughout the year, he coordinated round-the-clock assistance to injured children, and dozens of telemedicine consultations were held. Based on the result of a systematic survey of the chief supernumerary pediatric surgeons of the Russian Federation, a consolidated report on the activities of the pediatric surgical service of the Russian Federation for 2021 was formed, which was important to develop prospects for its further development.
 The work plans of the chief pediatric surgeon for 2023 include the completion of important documents for the specialty: The procedure for providing surgical care to children and the Professional standard for a pediatric surgeon. There was also a task of implementing interregional neonatal surgery centers in the Far Eastern Federal District, and expert, educational work, and audit of childrens surgical clinics will be continued.

Exploration of acceptable operating range for a compression system in a double bypass engine

The variable cycle engine is distinguished by its highly adjustable compression system, whose aerodynamic characteristic is extremely complex. To explore the regulation range of a double bypass engine compression system, a multi-dimensional analysis method is developed, through which the coupling mechanism between the compressor component and the bypass is examined. The operation zones of the compressor components and the bypass system are proposed, and the operation range of the compression system is obtained by calculating the overlapping part of the operation zones. The results show that in the double bypass mode, there exists a minimum mode selector valve area and a minimum core driven fan stage stall margin that ensures a feasible bypass flow, the two parameters correspond to each other. Under the given fan and core driven fan stage conditions, the maximum value of the inner bypass ratio is restricted by the upper limit of the forward variable area bypass injector and the maximum Mach number in the total bypass, while the minimum value of the inner bypass ratio depends on the lower limit of the forward variable area bypass injector geometry and the system recirculation margin. The single bypass mode is a unique condition of the double bypass mode, as the operation zone of the compressor component degenerates from a two-dimensional surface to a straight line. There are multiple bypass states available in the single bypass mode, while the regulation range of the bypass ratio is jointly restricted by the operation range of the high pressure compressor and the aerodynamic boundary of the forward variable area bypass injector.

UKRAINIAN EDUCATION IN THE CONDITIONS OF WAR: NEW CHALLENGES, THREATS AND VECTORS OF CHANGES IN THE CONTEXT OF ENSURING THE QUALITY OF EDUCATION

The article analyzes the state of the education system in the conditions of russian aggression against Ukraine. The article is based on legislative and normative documents regulating the legal regime of martial law in Ukraine and the peculiarities of the functioning of the educational system during this period, as well as materials and research results of the Ministry of Education and Science of Ukraine, the State Service for the Quality of Education, the State Scientific Institution «Institute of Educational Analytics», of the National Agency for Higher Education Quality Assurance. Official statistical data on the number of educational institutions and students studying at them, as well as damaged and destroyed educational institutions during the war, are provided. Challenges and threats faced by the educational system during the aggression of the russian Federation against Ukraine, its impact on the functioning of the educational system and ensuring the quality of education, including: threats to the life and health of participants in the educational process, large-scale destruction of educational infrastructure, significant losses of the contingent are highlighted education seekers, pedagogical and teaching staff, restrictions on access to education, loss of administrative educational control in territories that have come under temporary occupation or are in the zone of active military operations, reduction of state and local budget expenditures on education. The results of the research showed that after the full-scale russian invasion of Ukraine, despite serious challenges and threats, the educational system at all levels survived and continued to function. At the same time, there were significant changes in the organization of educational activities of educational institutions, which undoubtedly affected the quality of the provision of educational services. These vectors of change related primarily to the security situation in different regions of the country, the choice of models for the organization of the educational process, its material, technical and information support, support for various categories of participants in the educational process, etc.

Rare plant gene pool of the Steppe of Ukraine in the war zone

The results of field and camera studies on the collection and compilation of information on the presence of rare, endangered, and typical natural plant groups that are subject to protection in the territories of nature reserves in the war zone and occupied territories are presented. It was established that two biosphere reserves (BZ) (40% of the total number), 9 nature reserves (PZ) (45%) 10 national natural parks (NPP) (17%) and 23 regional landscape parks (RLP) (30%), 48 protected tracts (6%), 48 reserves of national importance (15%). In addition, a number of protected areas were in the war zone and have now been liberated from occupation, namely one radiation-ecological biosphere reserve, one nature reserve, 8 national natural parks, 8 regional landscape parks, 65 protected tracts, 20 nature reserves of national importance. The conducted analysis of the rare phytocenofund of Ukraine showed that in the pre-war period in the current zone of military operations and in the occupied territories there were plant groups of 58 formations and 513 associations of almost all the main types of vegetation of Ukraine (except meadow), which is 36% of formations and 52% of rare associations from of the entire rare phytocenofund of Ukraine. According to their sociological status, they are divided into 149 associations of 25 formations of rare natural plant communities that are subject to protection; 248 associations of 23 formations of natural plant groups that are under threat of extinction and subject to protection; 116 associations of 10 formations of typical natural plant communities that are subject to protection. Negative impact on natural ecosystems in the territories of the PZF. The work also provides an assessment of the negative impact on rare groups in the territories of the PZF, located in the combat zone and occupied territories.

Impact of spray dynamics on combustion instabilities investigated by changing the atomizer recess in a swirl combustor

The present article is aimed at identifying the impact of spray-wall interaction on combustion instabilities. This is achieved by systematically modifying the liquid fuel atomizer location with respect to the injector outlet in experiments carried out on a single-injector swirling combustor. The injector is characterized by a high swirl number and a relatively high pressure drop, and features a pressure atomizer that delivers liquid heptane fuel in the form of a fine spray. In the first set of experiments, longitudinal self-sustained oscillations (SSOs) are examined by varying the atomizer recess distance and using three combustion chamber lengths. Three distinct instability regions characterized by jumps in amplitude and frequency are observed as a function of the atomizer recess. At lower SSO frequencies (obtained for longer chambers), the pressure fluctuation amplitude in the chamber decreases as the atomizer recess distance is reduced, tending towards a stable operation. An opposite behavior is observed at comparatively higher SSO frequencies (obtained with a shorter chamber), where the system becomes less unstable at higher atomizer recess distances. The oscillation frequency is also found to change and increases as the recess distance is reduced. Three recess distances corresponding to each zone of operation are selected to further analyze the flow and flame structures and dynamics. It is found that the mean velocity profiles only reveal moderate differences in the air flow field, but there are significant changes in the fuel spray distribution in the neighborhood of the injector axis. Laser sheet images of the spray reveal two patterns—one where the spray predominantly interacts with the injector end piece when the atomizer is recessed, and the other where this interaction is minimal. In the latter case, corresponding to a small recess, the fuel spray is directly conveyed into the chamber. It is next found that the spray distribution affects the flame pattern defining two distinct configurations. Finally, the flame response to external disturbances is characterized by flame describing functions (FDFs) that allow carrying out a stability analysis. FDF results obtained with two independent methods indicate that the gain and phase at the three recess positions vary substantially and that this can be used in combination with a low-order model to interpret the instability behavior of the system. This study might serve to guide the modeling of combustion dynamics and help design injectors that are less sensitive to instabilities.

Hamiltonian Additional Damping Control for Suppressing Power Oscillation Induced by Draft Tube Pressure Fluctuation

The power oscillation induced by pressure fluctuation in the draft tube of the hydraulic turbine is one of the limiting factors preventing the Francis turbine from operating in the vibration zone. At the present power grid with a high proportion of renewable energy resources, we try to improve the load regulation ability of the hydropower units by extending the stable operation zone to the vibration zone. By the mathematical modelling of pressure fluctuation, this paper gives an analytical expression of the power oscillation. We derive the extended Hamiltonian model of the hydropower unit where power oscillation is external excitation. Secondly, the damping injection method introduces some desired interconnection and damping matrices as the Hamiltonian damping factor into the additional damping control. Finally, through theoretical analysis and experimental simulation, this research discusses the resonance characteristics of pressure fluctuation and power oscillation, the equivalent analysis between the damping factor and equivalent damping coefficient, and the control design of vibration zone crossing during the start-up. Simulation results show that when r25 = 1.3, the minimum power oscillation amplitude is 0.5466, which is equivalent to an increase in D by 20. The maximum oscillation amplitude decreases by 4.6%, and the operation limited zone is reduced by 10.1%. The proposed additional damping control can effectively suppress the power oscillation and expand the regulation range.

Multiphase Interleaved Converter Based on Cascaded Non-Inverting Buck-Boost Converter

This paper proposes an interleaved buck-boost converter with fewer switches. A single buck converter is followed by n parallel interleaved boost converters in the proposed converter. Aside from the reduced switch count, the proposed converter has the following benefits: soft start-up and shutdown capabilities. Furthermore, the buck stage protects power electronic devices and isolates the supply during load failure or overload. Furthermore, with the same switching scheme, the proposed converter can function as an interleaved boost converter for high voltage gain requirements. Furthermore, it provides quick dynamic performance with a smooth transition from buck to boost mode. This paper investigates the proposed three-phase interleaved buck-boost converter's eight operating zones for non-overlapping gate signal operation.

Theoretical and Psychological and Pedagogical Bases for Selection of the Content and Methods of Professional Training of Military Services of the National Guard of the Russian Federation for Interaction with the Local Population

The article actualizes the problem of transformation of professional education, in particular military education, to organize qualitative training of military personnel for the execution of service and combat tasks both in everyday activities and during the execution of tasks in the zone of special military operation. Particular attention is paid to the selection of content and methods of vocational education from the perspective of interaction of servicemen with the local population. The aim of this article is to provide a theoretical and methodological substantiation of the selection of content and methods of professional training for the military personnel of the National Guard of the Russian Federation in the context of interaction with the local population. Research methods: analysis and synthesis methods were used to determine theoretical conclusions, allowing to establish regularities arising in the consideration of interaction of servicemen with the local population. In the empirical part, the interview method was used. The methodological basis is represented by current sociological, psychological, and pedagogical concepts reflecting the essence of the concept “interactionˮ. The conclusion is based on the results of the conducted empirical research, which revealed characteristic difficulties experienced by servicepersons when interacting with the local population. The conclusion is that members of the armed forces need to have some knowledge of the theory of interaction in their education and training to interact with the local population, as well as ways to establish contact with the local population.

Organization of effective training in the discipline of fire training of cadets and students of educational institutions of the Ministry of Internal Affairs of Russia.

The purpose of this study is to organize effective training of cadets and students of educational institutions of the Ministry of Internal Affairs of Russia in the discipline of fire training, aimed at the formation of trainees' professional competencies that are necessary for the effective use of firearms by police officers during the performance of official duties to protect the life and health of citizens, as well as to ensure their own safety. The relevance of the study is due to the fact that currently the Interior Ministry employees are serving in special conditions in the zone of a special military operation. The objective of the scientific article is to analyze and propose a more effective algorithm for fire training, which is mainly aimed at acquiring the skills of high-speed and accurate shooting from different positions, from behind cover, in motion, as well as shooting with the left hand from a Makarov pistol, an AK-47 assault rifle, while the trainees are equipped with a bulletproof vest and protective helmet. The practical significance of this study is to improve the quality of fire training of cadets and students of educational institutions of the Ministry of Internal Affairs of Russia, taking into account the conduct of a special military operation and the fact that Interior Ministry employees serve in special conditions in new regions of our country (in the DPR, LPR, Kherson and Zaporozhye regions) imposes increased requirements for the level of fire training of employees.

Public control over the relocation of strategic objects of state ownership

The relevance of the chosen study subject is due to the fact that the full-scale invasion of the Russian Federation in Ukraine caused the need to move enterprises, especially strategic objects of state ownership, from the zone of active military operations to safer regions. Therefore, there is a need to make adjustments to the field of public control over objects of strategic importance for the economy, security, and life of the country in a difficult time for it. The purpose of the study is to determine the state of public control as a regulation of the relocation process in the legal context of regulatory support and suggest improving state regulation, considering the existing norms of national legislation, regulatory acts, and programmes. In the process of writing the study, general scientific and special methods were used, such as: analysis and synthesis, deduction and induction, formalisation, formal legal, comparative legal, and the method of legal modelling. As a result of the study, the legal regulation of public control of relocated strategic objects in the system of existing relocation procedures is analysed. Doctrinal and legislative approaches to the interpretation of control, public control, strategic enterprises, and relocation itself are described. Features of international support for the relocation of Ukrainian enterprises to safer regions are considered. The main methods of optimising the relocation process have been identified, emphasizing the necessity to legislatively define the process itself and the related concepts. Additionally, the regulatory framework for public control over strategic enterprises has been elaborated upon. The necessity to establish a special legal regime for public control over relocation is justified. The practical value of the results obtained lies in the fact that they can be used in the development of new regulatory legal acts that will determine the proper legal mechanism in one codified act on the relocation of businesses from non-safe territories.

The use of a neural network in solving problems of recognition and classification of spacecraft by their optical images

In recent years, the number of space objects located in near-Earth outer space, especially in the near operational zone, has increased significantly due to the build-up of space groupings, including dual-use (for example, Starlink) and the remnants of their vital activity (space debris). This factor increases the importance of the task of recognizing and classifying space objects by type in the shortest possible time and entering them into the main catalog of space objects. The developed methodology allows automated analysis of optical images of space objects using software to solve the problem of their recognition and classification by type using a convolutional neural network. The purpose of the study is to increase the efficiency of processing and analysis of optical images of spacecraft. The experimental results of the study confirm the achievement of the research goal. The developed methodology contributes to the development of software and hardware for image processing and can be used in calculations and data preparation for information support of interested officials. For the first time, a training set for a convolutional neural network has been prepared using real optical images of spacecraft obtained in the visible range.

ENGINEERING BIOGEOCHEMISTRY: FROM V.I. VERNADSKY'S FUNDAMENTAL IDEAS TO TECHNOLOGICAL SOLUTIONS

At present, it is possible to identify a number of new directions for the development of biogeochemical research, at the junction of fundamental and applied studies. A novel field of research is being formed, namely, engineering biogeochemistry, within the framework of which innovative biogeochemical technologies and technological processes based on modeling and management of ecosystematic biogeochemical cycles are being developed. The application of these innovative technologies for the restoration of disturbed and polluted impact ecosystems, in particular, polar ecosystems in the zones of operation of gas-producing enterprises, is considered. Technological examples of calculations of geoecological risks, as well as microbial contamination risks are given. A pool of the developed biogeochemical technologies and their connection with other innovative technologies within the framework of gas-producing companies is shown.

Prediction of energy and cavitation characteristics of high specific speed Francis hydraulic turbines

BACKGROUND: Cavitation is a phenomenon that occurs in vane hydraulic machines: pumps, hydraulic turbines, when the pressure in a certain area of the flow reaches the level of saturated steam pressure. Its occurrence depends on the design and mode of operation of the hydraulic turbine. In order to design a hydraulic turbine with high cavitation qualities, it is necessary to be able to reliably predict this phenomenon.
 AIMS: The article describes approaches to modeling the operation of Francis hydraulic turbines based on the ANSYS software package.
 METHODS: Using quasi-3D methods was modeled turbine blade system with 75 meters head. Hydrodynamic computation carried out in single-phase and two-phase formulations using the ANSYS CFX package.
 RESULTS: The design of a flow path Francis turbine 3D solid model with a specific speed coefficient ns =283 has been completed. The flow part of the hydraulic turbine includes a spiral case, a stator, a guide vane, an impeller and a draft tube. Computational modeling of the flow of a single-phase viscous fluid in a hydraulic turbine in different modes was carried out to construct a universal characteristic. The optimal efficiency is found and the flow characteristics are calculated. The losses in the elements of the flow part of the hydroturbine under various operating modes are determined, the zone of optimal operation is found. The cavitation flow is calculated using a two-phase flow model (water-steam). For both sides of the impeller blade, a pressure distribution was obtained, which can be used to judge the possibility of cavitation in areas where the pressure of the water column is less than the vaporization pressure. The value of the critical cavitation coefficient for the three most unfavorable modes was determined, and the dependence of the efficiency on the cavitation coefficient was constructed. The area occupied by steam on the blade during cavitation flow is visualized, its area is determined relative to the surface area of the blade.
 CONCLUSIONS: The designed hydraulic turbine has good energy and cavitation qualities, confirmed by the calculation. This version of the hydroturbine can be used as the initial one with further optimization of the blade system and elements of the flow path, to improve the energy and cavitation qualities.