bluuebunny/crossref_metadata_2025 huggingface dataset:
Nexus between Remittances and Economic Growth in Nepal: An ARDL Bound Test Cointegration Approach
Authors: Adhikari Dipa
Published: February 2025

This paper aims to investigate the nexus between remittances and economic growth in Nepal from 1993 to 2023, employing an Auto-Regressive Distributed Lag (ARDL) bound test cointegration model with time series data analysis techniques. The empirical findings reveal that both long-run and short-run coefficients indicate statistically significant and positively impact remittances on the Nepalese economic growth during the investigation period. This study's findings suggest that remittances play a pivotal role in improving living standards, economic development, and reducing poverty in Nepal. Moreover, this study found that government expenditures and labor variables have a positive influence on economic growth in the country. These results underscore the critical importance of remittances as a driver of sustainable development. The study results emphasize the need for targeted improvements in the management and effective utilization of remittances, positioning it as a strategic catalyst for promoting economic advancement in Nepal.
Knowledge of Health Insurance Program, Utilization, and Service Satisfaction among Insured in Suryabinayak Municipality, Nepal
Authors: Bhatt Khem Raj , Aryal Bhagwan , Khanal Kalpana , Adhikari Anup
Published: February 2025

The health insurance program is a social protection and health security program of the Government of Nepal that aims to enable its citizens to access quality healthcare services without placing a financial burden on them. Health insurance is essential for reducing financial barriers to healthcare and ensuring equitable access to health services. This study aimed to assess knowledge of the health insurance program, its utilization practice, and satisfaction with the service among the locals of Suryabinayak Municipality, Bhaktapur District, Nepal. A descriptive cross-sectional study used a structured questionnaire to collect data from 422 households. There was a high level of awareness (73.9%) and service utilization (38.4% using services frequently), with an 86% satisfaction rate among users. However, significant gaps remain in knowledge about specific benefits and access to emergency services, as well as issues with medication availability. Additionally, 7.1% of respondents experienced delays in renewal due to a lack of medicine. Health-insured people had a high level of awareness about the health insurance program, however, they had knowledge gaps in various aspects of the policy. Access to emergency care and essential medications remained questionable, which demanded targeted outreach and educational initiatives.
SIMULATION OF HYDRODYNAMIC AND THERMAL PROCESSES IN A REVERBERATORY FURNACE WITH A VORTEX FLOW CHAMBER
Authors: Penkovyi T.O. , Khalatov A.A , Goryslavets Y.M.
Published: February 2025

The problem of aluminum recycling in the Ukraine is particularly important problem due to the lack of primary production of the raw material in the country. Therefore for the aluminum production the reverberatory furnaces are used. The interesting solution, allowing reduce the amount of metal burned on the surface of liquid metal during melting. For this purpose, lightweight metal is grinded and then is melted in the vortex flow of liquid metal.
The disadvantage of existing system with vortex flow of metal is application of the centrifugal mechanical pump, reducing the reliability and service life of existing designs due to the pump blades operation in an aggressive environment of liquid metal.
To overcome this problem, the six-pole arc inductor was proposed to be used in the design. This paper provides a comparative analysis of two structural designs of the reverberatory furnace with an attached chamber of metal vortex. The driving force for a metal flow is created by a six-wave arc inductor.
The design efficiency was evaluated by the temperature difference between the maximum and average temperatures in the main part of the furnace bath. The option that provided the smallest temperature difference was considered as the best one. The angular speed of a liquid metal in the vortex chamber, which ensures the suction of grinded particles into the liquid metal volume, where their melting takes place, was also taken into account.
From the results of two designs comparison, the conclusion was made for tangential connection of the pressure channel (θ = 0), the best temperature uniformity was obtained in the furnace volume while at θ = 45° the best velocity and temperature distribution in the vortex chamber was occurred.
For a more detailed assessment of two designs simulation taking into account the formation of a meniscus on free surface of the liquid metal should be taken into account
CONVECTIVE INSTABILITY OF BIOFLUIDS UNDER THE ACTION OF MICROORGANISMS
Authors: Avramenko А.А. , Kovetska Yu.Yu. , Skitsko O.I. , Oliinyk L.V.
Published: February 2025

The article presents the results of a study of the instability of the bioconvective flow of gyrotactic microorganisms in a flat vertical layer. When solving the problem, the Lorentz approach was used, which made it possible to determine boundaries of different flow regimes. The dependence of the criterion of monotonic stability on the geometric structure of the microorganisms is analyzed. Calculations indicated that the spherical shape of microorganisms contributes to the stabilization of the conditions of bioconvection. The effect of the Schmitt number on the criterion of oscillating stability is analyzed. It has been determined that for elliptical microorganisms at low Schmidt numbers (Sc<8) the process of oscillatory instability stabilizes. A relation was obtained for the critical Rayleigh number , which describes the conditions for the appearance of a strange attractor and undamped turbulent pulsations. The analysis showed that the dependence of for the constant values of the Schmidt number has a monotonically increasing character.
ANALYSIS OF PROSPECTS AND SUSTAINABILITY ISSUES OF LIQUID MOTOR BIOFUELS PRODUCTION IN THE EU AND IN UKRAINE
Authors: Geletukha G.G. , Zheliezna T.A. , Drahniev S.V.
Published: February 2025

The purpose of the work is to analyse prospects for the production and use of liquid biofuels in Ukraine and to suggest relevant recommendations for the development of this direction, taking into account sustainability issues. The transition to biofuels is one of the effective measures for decarbonization of transport, which undergoes this process with difficulty in comparison with other energy sectors. According to 2020 data, the share of renewable energy sources in the gross final energy consumption in the EU’s transport sector is 10.2%. EU Directive RED II aims to increase this indicator to at least 14% in 2030, including the contribution of advanced biofuels and biogas produced from specified types of raw materials, at least to 3.5%. To be included in achieving the goals, motor biofuels must meet the sustainability criteria on land use and the requirements for reducing greenhouse gas emissions. The European Commission has the strictest approach to biofuels sustainability issues compared to the views of some European and international experts. In recent years, bioethanol has been produced only in small volumes in Ukraine, and there has been no production of biodiesel at all. Nevertheless, in the period until 2030, it is planned to significantly increase the consumption of motor biofuels, including advanced ones. Currently, the development of this direction in Ukraine is hindered by a number of barriers. It is recommended to create favourable conditions for the development of domestic production of motor biofuels. This may include a reduction in the excise tax, the abolition of compulsory tax bill for the full rate of excise duty when transporting bioethanol, the introduction of an export duty on rapeseed, and some other measures.
PROSPECT FOR THE USE OF BIOFUELS IN WOTERBORNE TRANSPORT
Authors: Drahniev S.V. , Zheliezna T.A. , Haidai O.I.
Published: February 2025

The purpose of the work is to analyze prospects for the use of alternative fuels in waterborne transport and to develop relevant recommendations for Ukraine. An effective measure of decarbonization of the global economy, which is an urgent issue today, is the transition to low-carbon and renewable fuels. From the point of view of using alternative fuels in waterborne transport, it is necessary to distinguish the short-distance transportation and deep-sea routes. In the first case, ships usually operate in limited geographical areas on relatively short routes with frequent port calls. Such vessels are often good candidates for testing new types of fuel (energy carrier) characterized by high energy conversion or storage costs. Deep-sea shipping requires the use of fuel (energy carrier), which is available all over the world and has a sufficiently high energy density. When determining promising alternative fuels for Ukraine’s waterborne transport, the following aspects have been taken into account: the level of technology development and its complexity; compatibility with existing engines, vessel fuel system and bunkering infrastructure; availability/accessibility of raw material and resource base; volumetric energy content, standardization, price, and reduction of greenhouse gas emissions during the life cycle of the fuel. According to the results of comparative analysis and assessment, the following alternative fuels are considered the most promising for Ukraine’s waterborne transport: biomethane (compressed or liquefied), biodiesel and hydrotreated vegetable oil, liquefied natural gas, as well as electric power installations with accumulator batteries. The development of each of these directions requires further study with conducting research and development activity.
TECHNO-ECONOMIC ANALYSIS OF SYNTHETIC RENEWABLE METHANE PRODUCTION
Authors: Klimenko V.M. , Suprun T.T.
Published: February 2025

The high instability and intermittent nature of the generation of electrical energy from solar and wind power plants led to the creation and improvement of PtG technologies as the main means of coordinating the operating modes of such power plants with electric networks. The PtG concept involves the production of synthetic renewable methane (SRM) using surplus energy from renewable energy sources with the use or storage of it through gas networks. To date, the world already knows a large number of projects that implement the specified PtG energy chain from obtaining renewable electricity, using it to generate hydrogen in certain electrolyzers, and to obtaining synthetic renewable methane by catalytic or biological methanation, i.e., combining hydrogen with carbon dioxide. Techno-economic analysis of a number of implemented projects made it possible to assess the influence of certain factors on the efficiency of the energy conversion process and thus determine ways to improve technologies. The levelized cost of synthetic renewable methane or also known as break-even price of the production of SRM was selected as a criterion for evaluating the efficiency of a particular technology. To date, unfortunately, there is not a single implemented technology that would allow SRM to be obtained at a price lower than the price of natural gas. The main directions for the development of PtG technologies and reduction of the levelized cost of synthetic renewable methane are:
- increasing the energy efficiency of electrolysis and methanation processes, i.e. increasing the output of the product (hydrogen or methane) while reducing energy costs; due to the improvement of technologies; the use of internal energy resources (heat of methanation, oxygen from electrolysis, etc.); application of more efficient processes for obtaining hydrogen, methane, carbon dioxide;
- reduction of capital investments due to the use of productive equipment and simpler technologies.
A separate task of this study was to determine the prospects for the development of PtG, the most attractive for the conditions of Ukraine. Such a perspective, in our opinion, can be the bioenergy direction of the development of renewable energy, which can be organically combined with the concept of SRM production in the PtG process. In this direction, we can expect to reach a profitable level of SRM production by 2030.
THE FEATURES OF HEAT EXCHANGE AND HYDRODYNAMICS WHEN AIR FLOWS AROUND BEAMS OF CYLINDERS
Authors: Khalatov A.A. , Kovalenko G.V. , Mulyarchuk M.A.
Published: February 2025

The purpose of the work is to evaluate various methods for intensifying heat transfer when air flows around bundles of cylinders while possibly minimizing pressure losses.
The results of experimental and theoretical studies of transverse air flow around a homogeneous bundle of cylinders are presented. The patterns of changes in the characteristics of heat transfer and aerodynamic resistance of a given cylinder bank under the conditions under consideration are analyzed. Based on computer modeling, the role of vortex structures in intensifying the heat transfer process is assessed. Data are presented on the effect of spiral grooves on the surface of the cylinders on the heat transfer coefficient and pressure loss. It is shown that the cross-section of spiral grooves also has a significant impact on the analyzed characteristics, while the oval cross-section leads to a greater intensification of heat transfer compared to grooves with a rectangular cross-section. It is noted that the sharpness of the edges plays a significant role when air exits the groove onto the surface of the cylinder. The results of experimental studies on the role of separating plates (splitters) on the aft surface of the cylinders are considered. It is shown that the presence, length and number of plates have a significant impact on the aerodynamic drag of the cylinder bank.
THE INVESTIGATION OF THE THERMOGASDYNAMICS OF A BURNER WITH REDUCED GENERATION OF NITROGEN OXIDES FOR A COAL DUST BOILER TPP 312
Authors: Kobzar S.G
Published: February 2025

The paper was consider the influence of the flue gas recirculation in inner duct of coal dust burner. The concept of a burner with reduced generation of nitrogen oxides for the TPP 312 boiler was created. It was used the principle of prolonging combustion process by separating the high-temperature zone from free oxygen by flue gas. The obtained results are shown that the proposed concept of the burner allows reduce nitrogen oxides up to 15%. The maximum reduction of nitrogen oxides was observed at 10% recirculation of flue gases/
DISCRETE-PULSE ENERGY INPUT (DРEІ) AND ITS IMPLEMENTATION USING ROTOR-PULSATION APPARATUS
Authors: Obodovych O.M. , Khomenko V.O. , Sydorenko V.V. , Stepanova O.E.
Published: February 2025

The article provides an overview of the design features of rotor-pulsation devices in which the method of discrete-pulse energy input is implemented – a method of intensification of heat and mass exchange processes, which contributes to the development and implementation of energy-saving technologies in various industries.
The idea of DPEI is to accumulate the energy previously distributed in the working volume in a stationary and arbitrary state in local discrete points of the system and then implement it in pulses to achieve the necessary thermophysical effects. Non-traditional methods of intensification of heat and mass exchange processes by means of discrete-pulse energy input into discrete environments formed the basis of new technologies for obtaining emulsions of various types. In many industries and everyday life, emulsions of various types are widely used, which leads to a constant increase in the requirements for their quality, first of all, stability and uniformity. Therefore, there is a high need for the development of highly efficient equipment and the determination of rational technological modes for processing “liquid-liquid” systems.
In the Institute of Technical Thermophysics of the National Academy of Sciences of Ukraine, equipment was created, the principle of which is to implement the DPEI method, in particular, rotary-pulsation apparatus (RPA).
Rotary-pulsation devices (RPA) are highly efficient, small-sized equipment for creating homogeneous mixtures of various liquids with a wide range of applications. With the help of RPA, issues are optimally solved in many technological processes, such as: dispersion, emulsification, mixing and homogenization of various systems, namely powdery, liquid, multicomponent, high and low viscosity media in many industries. The most important indicator of RPA performance is the size of dispersed emulsion particles obtained after processing in RPA from a mechanical mixture of mutually insoluble liquids or components that are difficult to mix.
FILM BOILING OF A LIQUID ON A VERTICAL PLATE IN A POROUS MEDIUM
Authors: Avramenko A.A. , Kovetskaya M.M. , Tyrinov A.I. , Kondratieva E.A. , Oliinyk L.V.
Published: February 2025

The paper presents results of the modeling of heat transfer at film boiling of a liquid in a porous medium on a vertical heated wall. Such processes are observed at cooling of high-temperature surfaces of heat pipes, microstructural radiators etc. Heating conditions at the wall were the constant wall temperature or heat flux.
An analytical solution was obtained for the problem of fluid flow and heat transfer using the Darcy-Brinkman porous medium model. It was shown that heat transfer at film boiling in a porous medium was less intensive than in the absence of a porous medium and further decreased with the decreasing permeability of the porous medium. A sharp decrease in heat transfer was observed for the Darcy numbers lower than five. Effects of different thermal boundary conditions on the heated wall on the heat transfer are insignificant.
ANALYSIS OF SUCCESSFUL CASES OF HEAT PRODUCTION FROM AGROBIOMASS IN EUROPE
Authors: Zheliezna T.A. , Drahniev S.V. , Bashtovyi A.I.
Published: February 2025

The aim of the work is to analyze the prospects for the development of bioenergy sector related to the production of second-generation aviation biofuels in the world and in Ukraine. The transport sector is a powerful source of greenhouse gas emissions. To meet the ambitious goal of achieving climate neutrality by 2050, the EU must reduce greenhouse gas emissions by 55% by 2030 from 1990 levels. According to experts, up to a third of this reduction is accounted for transport. Compared to other sectors, transport is difficult to decarbonize; this is especially true in segments such as aviation and water transport where electrification opportunities are limited. Therefore, in these segments it is necessary to move, first of all, to the use of second generation liquid biofuels. Today, the only technology for alternative aviation fuels that has fully reached the commercial level is the production of hydro-treated esters and fatty acids (HEFA). The reason for the possibility of commercialization was the development of technology for obtaining renewable diesel – hydro-treated vegetable oil (HVO). Each HVO plant can separate 15-50% of the fraction of hydro-treated esters and fatty acids, from which it is possible to obtain such aviation biofuel as synthetic paraffin kerosene (HEFA-SPK). The results of the preliminary feasibility study for the production of HEFA from false flax oil in Ukraine show that under the current conditions, such a project is not profitable given the high cost of this oil. To ensure profitable production and sale of HEFA aviation biofuel on Ukraine’s domestic market, it is necessary to work towards reducing the capital and operating costs of the project and/or introduce a temporary state subsidy for the production of sustainable liquid biofuels.
HEAT TRANSFER DURING TRANSVERSE AIR FLOW AROUND A SINGLE-ROW BUNDLE OF CYLINDERS WITH SPIRAL GROOVES OF VARIOUS CROSS SECTIONS
Authors: Khalatov A.A. , Kovalenko G.V. , Mulyarchuk M. A.
Published: February 2025

The aim of the work was to study the heat transfer and hydraulic resistance of a single-row bundle of cylinders with spiral grooves of various types on the outer surfaces. The task was to compare the heat transfer and hydraulic resistance of cylinders with spiral grooves with a rectangular cross section and grooves with an oval cross section in a cross-sectional air flow. The experiments were carried out in an open-type wind tunnel in the range of Reynolds numbers 3000 < Re < 16000 at air temperatures from 10 to 20 °С. The calorimetric method of melting ice was used. The heat transfer coefficient and the Nusselt number were calculated from the balance equations, and the Euler number was calculated from the value of the pressure drop. The Reynolds analogy factor was determined from the Nusselt and Euler numbers. An analysis of heat transfer and hydrodynamics during air flow around a bundle of cylinders with grooves was performed. Different types of spiral grooves on the surface of cylinders are considered. It is shown that the best heat transfer results were obtained for cylinders with steps of 10 mm and 40 mm. Cylinders with 20mm groove pitches were midway between 40mm grooved cylinders and smooth cylinders in terms of efficiency. This fact may be due to the peculiarities of the formation of vortices on the rear surface of the cylinder. The effect of groove geometry on hydraulic resistance and heat transfer coefficient was investigated. It was established that the flat side walls of the grooves create greater resistance than the curved ones in the range of Reynolds number change from 3000 to 4500. It is shown that the dependence of the heat transfer coefficient on the air speed is non-monotonic in nature. At the same time, the use of grooved cylinders with straight side walls leads to an increase in heat transfer in the range of Reynolds numbers Re from 7000 to 16000.
KINETIC REGULATIONS PROCESS OF CONVECTIVE DRYING OF FLAX SEED SNACKS
Authors: Sniezhkin Yu. F. , Husarova O.V.
Published: February 2025

The main component of the studied snacks is flax, which is rich in Omega 3, polyunsaturated fatty acids, fiber and vitamins A, B, E. The product does not contain emulsifiers, baking powder. The natural composition of raw materials limits the parameters of dehydration, requires such conditions of the process, which will preserve the most valuable components of the material. Careful analysis of the process kinetics is required to substantiate the rational drying parameters.
The purpose of the work is to study the kinetics of moisture exchange depending on the process parameters; thermal audit of the operating convective drying unit; identifying ways to reduce energy costs during dehydration of snacks.
Research methods. The study of the kinetics of the snack drying process was performed on an experimental convective stand with a system of automatic recording and processing of information at a drying agent temperature of 75, 90 and 90...80 ºC, speed 1.5 and 2 m/s, moisture content 11 g/kg dry air.
Results. The results of experimental studies have shown that the use of step-wise dehydration mode 90…80 °C compared to one-stage drying at 75 °C leads to a process acceleration of 15%, and in the 90 °C mode - by 26%. Reducing the duration of the process by increasing the speed of the drying agent from 1.5 to 2 m/s at a temperature of 90 oC is almost non-existent.The organoleptic characteristics of the experimentally obtained snacks did not differ from those produced industrially and met the standards.
Conclusions. Summarizing the results of thermal engineering audit and analysis of drying conditions of dehydrated material, rational regime parameters of the process are determined, additional structural elements of the dryer are developed and installed. Due to the improvement of the design of the drying unit, a uniform distribution of the flow rate of the drying agent, its temperature and moisture content is achieved. Such measures made it possible to intensify dehydration, reduce the duration of the process and reduce electricity consumption by 15…26%.
APPLICATION OF DIFFERENT DRYING METHODS IN DRY MUSHROOM CONCENTRATE TECHNOLOGIES
Authors: Avdieieva L.Y. , Dekusha H.V. , Turchyna T.Y. , Makarenko A.A.
Published: February 2025

A paper is devoted to the review of existing methods of drying the fruiting body of the shiitake mushroom, which is a valuable source of biologically active substances. The advantages and disadvantages of different methods of its drying are analyzed. Given here are the results of research on the influence of different drying methods and their parameters on structural and mechanical properties, chemical composition, content of aroma-forming substances and other compounds. When drying shiitake by convection in the temperature range of 50–60°С, compounds of phenolic nature, organic acids, nucleotides, sulfur aromatic substances are maximally preserved and the unique aroma of the mushroom is enhanced. The advantage of radiation drying is a lower degree of shrinkage of dried shiitake, a higher rehydration coefficient and hardness, while the duration of drying is 66% shorter compared to the sublimation drying method. The vacuum drying method allows to achieve a high quality of the product, however, the duration of the process is significantly increased and the content of aromatic substances is reduced. Radiation drying in combination with hot air makes it possible to obtain a dry form of shiitake with a high content of protein and biologically active polysaccharides and reduce the process time by 37.5% compared to convective drying. The use of spray drying has a high economic feasibility and the possibility of organizing the industrial production of high-quality dry mushroom powder in large volumes. When using this drying method, it is advisable to add dextrin additives, which improve the structuring and moisture-conducting properties of the suspension and its heat resistance, and also contribute to the preservation of the unique aroma of the mushroom due to the encapsulation of the aroma forming substances. Studying the effects of various drying methods on the physicochemical properties of shiitake mushrooms will improve existing technological processes and obtain a product with desired properties.
TECHNOLOGICAL PERSPECTIVE OF LARGE-SCALE PRODUCTION OF LOW-CARBON HYDROGEN NEAR OPERATING NPP UNITS IN UKRAINE
Authors: Snezhkin Y.F. , Ulanov M.M.
Published: February 2025

Achieving net zero carbon dioxide (CO2) emissions by 2050, as presented in the IPCC's special report on global warming at 1,5 °C, has prompted large-scale use of the new carbon-free energy carrier hydrogen to decarbonize the economy. The production of hydrogen using electrolysis units near the units of the existing nuclear power plants of Ukraine allows for the organization of large-scale production in the short term and can serve as a supplement to the production of hydrogen using renewable energy sources. On the basis of statistical data regarding the operation of NPP power units during 2018-2021, average annual coefficients of use of the installed capacity of power units were calculated and the optimal electrical power of the electrolysis plant was proposed. Taking into account the technological parameters of such an installation, namely, the consumption of electrical energy for the production of 1 kg of hydrogen at the level of 52 kW·h and the consumption of feed water in the amount of 22 liters, the total productivity of low-carbon hydrogen was obtained in the amount of 17417 kg per hour or 148 thousand tons per year. And taking into account the underutilization of existing nuclear power plants, the potential for low-carbon hydrogen production may reach from 444 thousand tons to 592 thousand tons per year in the short term.
STUDY OF LOCAL EXERGETIC LOSSES OF DIFFERENT TYPES IN THE HEAT RECOVERY SYSTEMS OF BOILER PLANTS
Authors: Fialko N. , Stepanova A. , Navrodska R. , Shevchuk S.
Published: February 2025

The paper presents studies of local exergy losses of various types in heat recovery systems of boiler houses. The purpose of the work is a comparative analysis of local exergy losses of various types, aimed at increasing the exergy efficiency of heat recovery systems.
The main tasks of the work:
- determination of the location and type of exergy losses in heat recovery systems for various purposes and their classification;
- obtaining exergy equations for calculation and calculation of local exergy losses of various types;
- conducting a comparative analysis of exergy losses and identifying ways to increase the exergy efficiency of heat recovery systems.
Research methodology: The authors used a comprehensive methodology for studying the exergy efficiency of heat recovery systems based on the exergy approach, developed by the authors. The technique includes structural-variant and balance methods of exergy analysis, as well as methods of heat transfer theory and hydrodynamics as applied to heat recovery systems.
Research results:
A classification of local exergy losses of various types has been carried out. Exergetic losses, which can be calculated from the input and output thermodynamic parameters of coolants, are referred to the losses of the first level. Exergy losses arising within individual elements of heat recovery systems as a result of irreversible processes during heat exchange between heat carriers are classified as losses of the second level. A system of equations has been developed for calculating local exergy losses of the first and second levels, and the corresponding exergy equations have been obtained. The calculation of local exergy losses of the second level for an air-heating heat exchanger was carried out for various values of the relative power of the boiler and the heat recovery efficiency of the heat exchanger. The conditions for the most effective reduction of total exergy losses in heat recovery systems by reducing local exergy losses of the first and second levels are substantiated. The results of the work can be used to design optimal heat recovery systems for boiler houses.
OSCILLATIONS DURING AIR FLOW NEAR DENTS ON A FLAT SURFACE
Authors: Khalatov A. A. , Kovalenko G. V.
Published: February 2025

The purpose of the work is to evaluate the intensification of heat transfer using various types of recesses when air flows around heat transfer surfaces with possible minimization of pressure losses.
The creation of compact devices for space and the armed forces requires solving similar problems. One of the proposed methods is the use of recesses on streamlined heat transfer surfaces.
This paper presents the results of experimental studies of flow around surfaces with depressions. Two types of recesses were considered: cylindrical and hemispherical segments. The influence of flow velocity on the formation of vortex structures when flowing around surfaces with depressions was studied. It was shown that at low speeds the flow has a diffuser and confuser character. As the speed increases at the inlet edge of the notch, the flow was been interrupted and a horseshoe-shaped vortex was formed in the notch. In this case, the boundary layer above the depression periodically collapses, and its lower end jumps from one half of the depression to the other, breaks off and turns into a Karman trace. With a further increase in speed, one of the ends of the horseshoe-shaped vortex rises above the depression, turning into a columnar one.
The nature of the flow over the depression was been analyzed. It was been noted that part of the shear layer is deflected towards the excavation and hits its rear (aft) wall. The location of the impact is the source of sound vibrations. It was shown, that when the frequency of any harmonic of these oscillations coincides with the frequency of shear layers vortex structures, these two phenomena begin to reinforce each other. Flow fluctuations near and inside the excavation could be divided into classes.

Hydrodynamic vibrations arising due to the instability of the shear layer.
Oscillations resulting from the interaction of standing pressure waves in the depression and acoustic waves emitted from places where the surface profile changes sharply.
Oscillations, when a sharp change in the shape of the surface causes the formation of vortices.

It was shown, that the sound pressure caused by the presence of depressions decreases with increasing boundary layer thickness.
CAVITATION TECHNOLOGIES AND NEW HEAT AND MASS EXCHANGE EQUIPMENT – A PROSPECTIVE DIRECTION FOR THE PREPARATION OF HYDROCARBON FUEL
Authors: Obodovych O.M. , Tselen B. Y. , Pereiaslavtseva O.O. , Stepanova O.E.
Published: February 2025

Considering that the import of oil and gas is decreasing, the cost of their production and supply is increasing, coal in Ukraine is becoming almost the only source of energy of local origin. In order to overcome the critical situation in the fuel and energy complex of the country, trends have been outlined regarding the development and implementation of energy saving programs, as well as the creation and implementation of new, efficient, environmentally friendly fuel technologies. One of the main ones is the transition to widespread use of hydrocarbon fuel (HCF).
The purpose of the work is the analysis of existing technologies and equipment for the preparation of hydrocarbon fuel. Demonstration of the effectiveness of the cavitation effect on the water-coal mixture. To propose new technologies and heat and mass exchange equipment working on the basis of the DPIE method as a promising direction in the preparation of HCF.
When conducting an analysis of existing technologies and equipment for the preparation of hydrocarbon fuel, the effectiveness of the cavitation effect is shown. It was established that before cavitation treatment, coal must be dispersed on various types of grinding equipment to an average particle diameter of 1000-500 microns. It is most effective to carry out cavitation treatment of hydrocarbon suspension with the use of heat and mass exchange equipment operating on the DPIE principle. This makes it possible to obtain a universal hydrocarbon fuel with a particle size of no more than 3 microns, which is suitable for burning in various energy devices, as well as to reduce specific energy consumption by almost 3 times compared to supercavitating fuels.
ANALYSIS OF FEEDSTOCK AND TECHNOLOGY BASIS FOR THE PRODUCTION OF DIESEL BIOFUEL IN UKRAINE
Authors: Drahniev S.V. , Zheliezna T.A.
Published: February 2025

The purpose of the work is to develop recommendations for the possibility of renewing the production and consumption of biodiesel in Ukraine with the subsequent increase in the production of hydrotreated vegetable oil. The current state and prospects of diesel biofuel production in the world are analyzed. Production technologies and fuel characteristics of biodiesel and hydrotreated vegetable oil are considered. Over the past twenty years, the global production of diesel biofuel has increased from 2 to 55 billion l/year. Currently, about a third of the total production volume is in the EU. Diesel biofuel is divided into two types, namely biodiesel and hydrotreated vegetable oil. They differ in production technology and chemical composition. Now, biodiesel, which is fatty acids methyl ethers, is the type of diesel biofuel that is mainly produced and consumed in the world. However, given the fuel characteristics and ease of use, in the future, it makes sense to switch to hydrotreated vegetable oil, which is actually a complete analogue of diesel fuel. In Ukraine, during at least the last decade, the production and consumption of biodiesel has been practically absent. Despite this, there are certain prerequisites for the possibility of developing this direction in the future. Such prerequisites include availability of a large feedstock base, as well as significant groundwork in this field. We consider it expedient to establish a legislatively mandatory share of biodiesel in diesel fuel consumed in Ukraine at the level of 5%; introduce an export duty on rapeseed; cancel the excise tax on diesel biofuel; introduce a system for collecting used cooking oil; resume methanol production in Ukraine; create a specialized laboratory for testing biodiesel quality properties according to current international standards. To implement the proposed measures, we recommend the development of a new program for diesel biofuel production in Ukraine or the inclusion of a respective section in existing or planned national strategic documents.
NONLINEAR ANALYSIS OF CONVECTIVE INSTABILITY OF REAL GASES IN POROUS MEDIA
Authors: Avramenko А.А. , Kovetska Yu.Yu. , Kobzar A.S. , Kozlova V.V.
Published: February 2025

The article is devoted to the study of the nonlinear instability of the Van der Waals gas in a gap with a porous medium of finite thickness heated from below. A fixed temperature difference is set between the upper cold surface and the lower hot one. The Lorenz approach was used to solve the problem. During a numerical solution, criteria for monotonic instability and oscillating instability were obtained. The results of calculations of the criterion for the appearance of a strange attractor in the phase space are presented, which can be interpreted as a criterion for the generation of undamped turbulent fluctuations. The nature of the dependences of the critical Rayleigh numbers on the physical properties of the gas, the porosity of the medium, and the parameters of the Van der Waals equation of state Waa and Wab is analyzed.
            The phenomenon of instability (formation of vortices in liquids or gases) in the space between two horizontal boundaries, when the lower one is heated, is widespread in technical applications. Lorenz developed a non-linear approach to the study of this phenomenon. This approach makes it possible to determine the criteria for the emergence of vortices and their transformation. This article uses the Lorenz approach to obtain instability criteria for a real gas whose properties are described by the van der Waals equation of state. This gas is in a porous medium. This combination of gas and medium has a wide technological application in the food, chemical and other industries. That is why the present study focused on this problem.
Specificities of the workflow and evaluation of the working conditions of the working main professions of industrial rubber and technology production
Authors: Rakhmetova A.M. , Alshynbekova G.K. , Tusupbekova G.A.
Published: February 2025

In the available literature there is a large number of diverse works on the assessment of the labor process and working conditions of industrial rubber production. At the sametime, it is of interest and there is a practical need for a sanitary-hygienic assessment of the working conditions of workers in basic occupations who are in contact with chemical substances of a general toxic and irritant action during production. The production of industrial rubber products is based on a multistage intermittent technological process using numerous chemicals of the second, third and fourth classes of toxicity. During a work shift, production personnel is exposed to fractional and short-term exposure to toxic substances, therefore, the toxic effects of chemicals used in the industrial rubber industry to workers are enhanced, which was the purpose of the study. To assess the work process and the working conditions of the workers of the main occupations of industrial rubber production, the study of air dustiness, microclimate, and relative humidity wasconducted. As a result of the research, it was established that one of the unfavorable production factors at the factory of the industrial rubber products is dustiness, air pollution, overcooling, overheating and considerable physical stress.
The Betpakdala saiga’s breeding and sex composition
Authors: Myrzabaev А.B. , Gongalsky K.B. , Ibraibekov Zh.G. , Brit’ko V.V. , Kanafina B.A.
Published: February 2025

The main issue in the article is that saigas have been inhabited in ancient times. At present, the main populations of saiga antelopes are stored only in the Kazakh land. The country has protected zones, changes in seasons and migration paths. The issues of mass involvement of saiga antelopes, measures and their survival are described. The «Altyn Dala» Association for the Conservation of Biodiversity of Kazakhstan for 2013 has been created to further improve the work of the Specially Protected Natural Areas (SPNA), i.e. saiga conservation. Nature Protection Initiative informs that nature protection personnel have been provided with special equipment and related trainings. End of November — beginning of December is avery important time for saigas, especially for males. The number of females is several times higher than males; however, females become weaker often, die or become food for predators, such as fox, corsac. The survival rate of these wild animals is very different. Life expectancy of males is 3–4 years, the age of females can reach up to 9 years. Therefore, wild antelopes grow rapidly. Females begin to be fertilized in 7 months. Malesare sexually active in two years. The morphometric characteristics of the internal organs of the saiga werestudied less than other morphological features (exterior, craniometric, etc.).
Экспрессия и очистка белка IalB Brucella spp.
Authors: Исабек А.У. , Тайлакова Э.Т. , Шыныбекова Г.О. , Строчков В.М. , Червякова О.В.
Published: February 2025

В последние годы наблюдается заметное распространение особо опасных инфекционных болезней, которые наносят большой экономический ущерб животноводству. Важнейшим и перспективным методом борьбы с инфекционными болезнями является иммунопрофилактика. Используемые в настоящее время вакцины для профилактики бруцеллёза требуют своего принципиального изменения и совершенствования. Одно из перспективных направлений при разработке безопасных и эффективных средств профилактики — использование протективных антигенных белков Brucella spp. Целью данных исследова-ний являлось получение рекомбинантного белка IalB Brucella spp.методом бактериальной экспрессии в Escherichia coli. В результате проведенных исследований ген, который кодирует инвазивный белок IalB, был амплифицирован с геномной ДНК Brucella suis и клонирован в бактериальный экспрессирующий вектор pET28b (+). Отработаны оптимальные условия экспрессии целевого гена в клетках E. coli, штамм ER2566 и условия очистки рекомбинантного белка — методом металл-аффинной хроматографии. Степень очистки белка составила не менее 95 %. При иммунизации рекомбинантным белком IalB в организме мышей вырабатываются антитела, которые детектируются в иммуноферментном анализе. Полученный рекомбинантный белок будет использован для разработки профилактических препаратов против бруцеллеза животных.
Selection of an effective DNA extraction method for the detection of Salmonellaby the polymerase chain reaction
Authors: Barmak S.M. , Sinyavskiy Yu.A. , Berdygaliev A.B. , Savitskaya I.S. , Sharmanov T.Sh. , Mendenhall I.Н. , Zholdybaeva E.V.
Published: February 2025

DNA extraction is a crucial step at using molecular and biological methods, since the result of PCR analysis largely depends on the quality and quantity of the obtained DNApreparations. In this work, we compared the efficiency of DNA extraction from bacteria in various ways: thetrizol method using TRizol commercial reagent, the CTAB method and the sorbent method using silica particles. It has been shown that the extraction of DNA from Salmonella bacteria on silica particles ensures higher sensitivity than the other methods. The amplification of the extracted DNA on silica particles is more efficient and allows obtaining reproducible results with the accuracy of a high degree. In the future, this method will be used to complete the test system for diagnosing salmonellosis. Introduction of the methods of express diagnosis into practice is extremely important, as quick and early diagnosis will allow counteracting the spread of infection in a timely manner, which in turn will improve the epidemiological and epizootological situation in the country.
Ecological monitoring of pastures of Kurti rural district of Almaty region
Authors: Seilkhan A.S. , Saibulatova V.B. , Atraybaeva R.N. , Beisenbaeva M.E. , Zhumagul M.Zh.
Published: February 2025

In the article the main indicators of the environmental monitoring system carried out in the territory of Kurti rural district, the main indicators of soil and chemical composition in the territory of Kurti rural district, their hydrological functions, climatic factors, as well as the bioticsequence and interaction of the unified system are studied. Integrated ecological monitoring of soil cover and vegetation features of the special rural district on the basis of dynamic changes in the territory and soil features of the relationship of a number of indicators, including one or more ecosystems. In the conditions of the local territory, agrochemical, ecological, climatic, soil and floristic compositions are studied, as well as productivity of pastures and the results of the number of livestock. Based on possible changes in the future, the relevance of the effective environmental monitoring increases in order to preserve the biodiversity of pasture lands and county territory in the future.
Выделение перспективных штаммов Bacillus megaterium и Bacillus subtilis, обладающих фосфатмобилизирующими и противомикробными свойствами
Authors: Жаппар Н.К. , Шайхутдинов В.М. , Байрон Л.Ж. , Мырзабаев Б.М. , Зейнелов К.А. , Шибаева А.К. , Ишмуратова М.Ю.
Published: February 2025

В статье представлены данные по выделению и изучению физиолого-биохимических свойств культурBacillus megaterium и Bacillus subtilis. В качестве материалов для выделения культур использовались образцы черноземных почв пшеничных полей. Из образцов выделены36 изолятов с противомикробными и17 изолятов с фосфатмобилизирующими свойствами. Микроскопическое наблюдение этих изолятов показало, что они представляют собой грамположительные, палочковидные, эндоспорообразующие бактерии. Согласно культурально-морфологическим и физиолого-биохимическим признакам выделенные изоляты идентифицированы как Bacillus subtilis и Bacillus megaterium. Изучена эффективность фосфатмобилизации штаммов Bacillius megaterium. В результате из выделенных 17 изолятов5 показали наибольшую солюбилизирующую способность на твердой среде. Определена солюбилизирующую способность на жидкой среде NBRIP, где содержание растворенного фосфора увеличилось в 4–7 раза, а рН культуральной жидкости у данных штаммов уменьшился с 7,0 до 5,1–5,4. Также проведены работы по изучению антагонистической активности выделенных штаммов Bacillus subtilis и Bacillus megaterium к2 тест-штаммам: Fusarium graminearum и Fusarium oxysporum. На основании полученных данных отмечено, что штаммы Bacillius megaterium АА4, АА7, АА8, АА15 и АА17, а также Bacillus subtilis AS7, AS14, AS22, AS29 иAS34 обладают антагонистической активностью по отношению к F. graminearum и F. oxysporum. Таким образом, получены перспективные штаммы для биоконтроля фузариозных заболеваний.
Study of resistant peculiarities of Juniperus sabinaand Juniperus communis in the conditions of Zhezkazgan industrial region
Authors: Maksutbekova G.Т.
Published: February 2025

At the article the results of assessment of winter-resistant, drought-resistant and gas-resistant of Juniperus sabina and Juniperus communisin the conditions of cities Zhezkazgan and Satpayev are conducted. Winter resistance indicators for kazak juniper were 5 points, for common juniper — 4 points; drought resistance of kazak juniper — 5 points, common juniper from 3 to 4 points. The results are shown that in the territory of the Zhezkazgan copper plan there is more damage to the leaf plates of wood plants than in the experimental comparison site of the Zhezkazgan Botanical Garden (the main arboretum). Thus, the percentage of damage was 2–2.5 times different. Kazak juniper is classified as highly gas-resistant culture, while common juniper is classified as weakly gas-resistant. This fact can be explained by the fact that the first species grows in the local natural flora — in the mountains of Ulytau, while the second species — introduced from the Main Botanical Garden (Almaty city). According to the results of many years of research kazak juniper is classified as very promising plants, that is, it can be widely used in mass greening of settlements of the Zhezkazgan region. Juniper common will be classified as promising species suitable for greening with squirrel and parks under the condition of regular watering.