Modeling of the floating of non-metallic inclusions when pouring steel into a mold in top casting / R. P. Andriukhin, I. Mamuzic, L. S. Molchanov, Y. V. Synehin

It is described in the paper the physical modeling of the metal flows pattern and the floating of non-metallic inclusions in the mold when pouring steel in top casting. The study of the effect of the speed and direction of metal flows in the mold on the time of floating up of nonmetallic inclusions is very important for finishing alloying and modification of steel in the mold during casting. The purpose of this study was to substantiate the similarity numbers for physical modeling of this process and determine their influence on the surfacing time and the determination of the rational casting method for the final alloying steel from the point of view of NMI removal and the mode of additives. In the course of the literature analysis, it was found that the movement of flows during steel casting can be described by the Reynolds, Froude, and Weber numbers, but their simultaneous compliance is impossible. Since no substantiation of the insignificant influence of the Weber number, in contrast to the Reynolds number, was found in early studies, the authors developed a technique, assembled an experimental facility, and carried out physical modeling. The results of physical modeling confirm the Weber number's self-similarity in the range from 104,75 to 105,5. According to the results of this study, the insignificant effect of the Weber number on floating up non-metallic inclusions when filling the mold in top casting was confirmed. It was found that the removal of deoxidation products occurs faster in top casting, and the time for their removal is significantly reduced with an increase in the liquid level in the mold at the time of additives.

Corrosion inhibition efficiencies of polymeric materials on alloy steel in dilute hydrochloric acid and sodium hydroxide solutions at ambient temperature / I. E. Ekengwu, O. G. Utu, K. O. Anyanwu

A corrosion control test was conducted on alloy steel, using polymeric coatings (polyurethane, bitumen (medium airing), and high-density polyethylene) in dilute HCl solutions of pH values 4, 7, and 12, respectively for acid, neutral and alkaline solutions at ambient temperature. In the study, Eighty-four coupons of alloy steel were used. The coupons were mechanized, ground, polished, etched with natal, and weighed using a digital weighing balance (Beva 206B). The mass of each coupon was recorded according to the tag number on them. Twenty-one of the coupons were coated with polyurethane, 21 coated with medium curing bitumen (MC), and 21 coated with high-density polyethylene, while 21 were left uncoated. Seven polyurethane-coated samples, bitumen coating, and uncoated coupons were suspended in dilute HCl solutions of pH values 4, 7, and 12. Every week, one sample is taken from each of the solutions, the coatings and the corrosion products were removed, and the coupons were etched with natal. Then the coupons were reweighed, and their masses were recorded in accordance with their tag number. The weight loss per unit area of the coupons, corrosion rate, and percentage corrosion inhibition efficiencies of the coatings was calculated over seven weeks. The results obtained were tabulated and represented graphically. From the results obtained, it is seen that the corrosion inhibition efficiency of polyurethane coatings is higher compared with bitumen and polyethylene. It is also seen from the graphs that the corrosion rate of the coupons is higher in acid, a little bit lower in alkaline, and much lower in neutral solution. It is also observed that the corrosion rates fall with time as the inhibition efficiency also falls with time.

Influence of heat treatment technologies on the structure and properties of the corrosion-resistant martensitic steel type AISI 420 / O. Lupyr, T. Hovorun [et al.]

One of the methods for increasing the complexity of chromium steel properties of martensitic class AISI 420 is the use of an optimal heat treatment mode. The steel of martensitic class AISI 420 has high resistance in atmospheric conditions (except for the sea atmosphere), in the river, and tap water. It is widely used in power engineering, in cracking units with a long service life at temperatures up to 500 <$E symbol Р>C, for furnace parts. Additionally, it is used in the following fields: the production of turbine blades, working in conditions of high temperatures and parts of increased plasticity, subject to shock loads, for products exposed to atmospheric precipitation, solutions of organic salts and other slightly aggressive environments; production of fasteners; production of parts for compressor machines operating with inert gas; production of parts operating at low temperatures in corrosive environments; production of parts for aviation purposes. It is shown that the optimal mode of heat treatment for a maximum hardness of 40 HRC is quenching at a temperature of 980 <$E symbol Р>C with cooling in oil and tempering at a temperature of 200 <$E symbol Р>C with air cooling. With an increase in the tempering temperature from 200 to 450 - 500 <$E symbol Р>C, the impact strength does not change much. Tempering at higher temperatures leads to the intense weakening of the steel. Simultaneously, a decrease in the impact strength is observed, the minimum value is reached at a tempering temperature of 550 <$E symbol Р>C. With an increase in the tempering temperature to 700 <$E symbol Р>C, the impact toughness increases, but the steel's hardness sharply decreases at such temperatures.

Carbonitration of a tool for pressing stainless steel pipes / I. V. Ivanov, M. V. Mohylenets [et al.]

To upgrade the operational stability of the tool at LLC "Karbaz", Sumy, Ukraine, carbonation of tools and samples for research in melts of salts of cyanates and carbonates of alkali metals at 570 - 580 <$E symbol Р>C was carried out to obtain a layer thickness of 0,15 - 0,25 mm and a hardness of 1000 - 1150 НV. Tests of the tool in real operating conditions were carried out at the press station at LLC "VO Oscar", Dnipro, Ukraine. The purpose of the test is to evaluate the feasibility of carbonitriding of thermo-strengthened matrix rings and needle-mandrels to improve their stability, hardness, heat resistance, and endurance. If the stability of matrix rings after conventional heat setting varies around 4 - 6 presses, the rings additionally subjected to chemical-thermal treatment (carbonitration) demonstrated the stability of 7 - 9 presses due to higher hardness, heat resistance, the formation of a special structure on the surface due to carbonitration in salt melts cyanates and carbonates. Nitrogen and carbon present in the carbonitrided layer slowed down the processes of transformation of solid solutions and coagulation of carbonitride phases. The high hardness of the carbonitrified layer is maintained up to temperatures above 650 <$E symbol Р>C. If the stability of the needle-mandrels after conventional heat treatment varies between 50 - 80 presses, the needles, additionally subjected to chemical-thermal treatment (carbonitration) showed the stability of 100 - 130 presses due to higher hardness, wear resistance, heat resistance, the formation of a special surface structure due to carbonitration in melts of salts of cyanates and carbonates.

Real power loss reduction by Rock Dove optimization and Fuligo Septica optimization algorithms / L. Kanagasabai

This paper aims to use the Rock Dove (RD) optimization algorithm and the Fuligo Septica optimization (FSO) algorithm for power loss reduction. Rock Dove towards a particular place is based on the familiar (sight) objects on the traveling directions. In the formulation of the RD algorithm, atlas and range operator, and familiar sight operators have been defined and modeled. Every generation number of Rock Dove is reduced to half in the familiar sight operator and Rock Dove segment, which hold the low fitness value that occupying the lower half of the generation will be discarded. Because it is implicit that individual's Rock Dove is unknown with familiar sights and very far from the destination place, a few Rock Doves will be at the center of the iteration. Each Rock Dove can fly towards the final target place. Then in this work, the FSO algorithm is designed for real power loss reduction. The natural vacillation mode of Fuligo Septica has been imitated to develop the algorithm. Fuligo Septica connects the food through swinging action and possesses exploration and exploitation capabilities. Fuligo Septica naturally lives in chilly and moist conditions. Mainly the organic matter in the Fuligo Septica will search for the food and enzymes formed will digest the food. In the movement of Fuligo Septica it will spread like a venous network, and cytoplasm will flow inside the Fuligo Septica in all ends. THE proposed RD optimization algorithm and FSO algorithm have been tested in IEEE 14, 30, 57, 118 and 300 bus test systems and simulation results show the projected RD and FSO algorithm reduced the real power loss.

Effects of metal particles on cold spray deposition onto Ti-6Al-4V alloy via Abaqus/Explicit / W. J. Hu

Titanium alloy is the main structural material of the aerospace system component. About 75 % of titanium and titanium alloys in the world are used in the aerospace industry. Hence, it is of great significance to study the surface deposition characteristics by cold spraying technology, taking Ti-6Al-4V alloy as an example, smoothed particle hydrodynamics (SPH) method in Abaqus/Explicit was used to spray aluminum, Ti-6Al-4V, copper, tungsten alloy (Walloy) and titanium particles onto Ti-6Al-4V substrate. The simulation results show that the deposition effect is good over 600 m/s, and higher energy is obtained for Ti-6Al-4V particles with the same properties as the matrix. For aluminum, Ti-6Al-4V, copper, W alloy, and titanium particles with different properties, under the same initial speed condition, the greater the density of the material, the deeper the foundation pit. W Alloy has the largest initial kinetic energy, the deepest foundation pit, and better surface bonding performance. The aluminum particle has the smallest initial kinetic energy, the shallowest foundation pit. However, the deposition effect of multiple aluminum particles has not improved. The collision process's kinetic energy is transformed into internal energy, frictional dissipation, and viscous dissipation. Besides, the internal energy is mainly plastic dissipation and strain energy. Therefore, it is recommended to use Ti-6Al-4V, copper, nickel, W alloy, and titanium particles for different occasions, such as Ti-6Al-4V substrate surface restorative and protective coatings. Pure aluminum particles are not recommended.

A fuzzy multi-criteria decision-making approach for power generation problem analysis / I. Emovon

The abundance of different energy sources such as coal, natural gas, and crude oil are in the Africa region, yet one of the lowest electric energy per capita consumption. Different factors have been attributed to this abysmal energy failure in the literature, leading to her slow economic and industrial advancement. These factors include poor maintenance of power generation infrastructure and lack of policy continuity, among others. The purpose of this article is to prioritize these power generation problems for proper budgetary allocation by managers of electric power. The fuzzy VIKOR technique is presented for the evaluation and ranking of these power generation problems. The analysis showed that poor maintenance is the most critical challenge of bedeviling power generation in Nigeria. The Fuzzy VIKOR produces the same result as the classical VIKOR used previously in resolving the problem. The proposed technique addresses the challenge of uncertainty and subjectivity by applying linguistic variables in the decision-making process, which the classical VIKOR is incapable of handling.

Design of digitally controlled DC-DC boost converter for the operation in DC microgrid / T. K. Barui, S. Goswami, D. Mondal

Renewable energy sources (RESs) are becoming increasingly important day by day to tranquilize the world's energy crisis and consume fossil fuels in the lower rung. A microgrid system that assimilates clean and green energy-based sources such as solar, wind, and biogas is acquiring much prominence over the conventional grid-based power systems in this day and age. For the up and running of the inexhaustible energy sources in the AC power network, numerous conversions of the power sources occur. In the process of conversion, some amount of power is lost, which minimizes conversion efficiency. However, with the increasing use of DC loads and Distributed Energy Resources (DERs), DC Microgrid could be more beneficial than the conventional AC power system by avoiding several types of drawbacks. This paper demonstrates an efficient system of digitally controlled boost converter for the parallel operation in DC microgrid. Here, the converter of 2,5 kW 400 V is designed and implemented to validate its functioning in a Microgrid. The whole system has been simulated in MATLAB with an input voltage ange of 220 - 380 V. It has been found that the designed converter can maintain the desired output voltage in the DC Busbar at and around 400 V. Finally, some simulation results have been presented to analyze the converter's operational characteristics and effectiveness in the practical domain.

Modeling of the meteorological balloon-Cube with LoRa-based ground station / V. Rastinasab, H. Weidong

Every day 80,000 weather balloons are launched to the Earth's upper atmosphere with meteorology payloads to provide accurate meteorological data. Meteorological data could be used for airport stations and weather stations. Meanwhile, there are many remote sensing satellites above the Earth's atmosphere, but balloons are still essential due to increased weather prediction accuracy. Many balloons launch into the atmosphere daily, but it would be a one trip tripe because this balloon goes to the atmosphere then transmits the meteorological data to the ground segment, and that is all no one looks to recycle it, on the other hand, if the balloon could be recycled there would be many financial benefits. This project presents a high altitude meteorological balloon-Cube relative to measuring atmosphere humidity, temperature, air pressure, and a photography payload for surface imaging that ascended up to 20 Km altitude Cube reach this altitude will eject box on the ground. The telemetry data are transmitted to the ground station through two communication applications, first using a LoRa based transceiver at which it receives a command from the LoRa ground station and the second one, and payload transmits the data by an SMS in 5 min after it lands on the ground. Therefore, it could be recycled. This paper presents a Cube-Balloon fabrication and flight test information to acknowledge this Cube's feasibility for real meteorological projects.

Boron-carbon coatings: structure, morphology and mechanical properties / Е. А. Kulesh, D. G. Piliptsou [et al.]

Boron-doped carbon coatings have been produced by a method combining the deposition of a pulsed carbon plasma coating and a boron flow formed as a result of the evaporation of a boron target by pulsed YAG:Nd<^>3+ laser irradiation. Phase, chemical composition, structure, and mechanical properties of composite boron-carbon coatings have been determined. Changes in the coatings' roughness depending on the boron concentration have been established using atomic force microscopy. It has been shown that the grain size is on the rise with increasing boron concentration. Raman spectroscopy has revealed that at a boron concentration of 43,2 at. %. There is a sharp increase in the ID/IG ratio, which indicates the carbon component's graphitization. Low ID/IG ratios are observed in the coating at low boron concentrations (no more than 17,4 at. %), suggesting a high content of carbon atoms with sp<^>3 bond hybridization. The coating studies, carried out by X-ray photoelectron microscopy, showed that boron could be in a free state or in the form of carbide or oxide depending on the concentration in the coating. In this case, with an increase in boron concentration, there is a decrease in the concentration of carbon atoms in the state with sp<^>3 bond hybridization, accompanied by an increase in the number of B-C bonds and a reduction in the boron concentration not associated with carbon and oxygen. These coating and chemical composition features determine the boron concentration's established non-monotonic nature on their microhardness, elastic and mechanical properties.

Thermodynamic and economic evaluation of gas turbine power plants / T. Oyegoke, O. I. Akanji [et al.]

Thermodynamic analysis and economic feasibility of a gas turbine power plant using a theoretical approach are studied here. The operating conditions of Afam Gas Power Plant, Nigeria are utilized. A modern gas turbine power plant is composed of three key components which are the compressor, combustion chamber, and turbine. The plants were analyzed in different control volumes, and plant performance was estimated by component-wise modeling. Mass and energy conservation laws were applied to each component, and a complete energy balance conducted for each component. The lost energy was calculated for each control volume, and cumulative performance indices such as thermal efficiency and power output were also calculated. The profitability of the proposed project was analyzed using the Return on Investment (ROI), Net Present Worth (NPW), Payback Period (PBP), and Internal Rate of Return (IRR). First law analysis reveals that 0,9 % of the energy supplied to the compressor was lost while 99,1 % was adequately utilized. 7,0 % energy was generated within the Combustion Chamber as a result of the combustion reaction, while 33,2 % of the energy input to the Gas Turbine was lost, and 66,8 % was adequately converted to shaft work which drives both compressor and electric generator. Second law analysis shows that the combustion chamber unit recorded lost work of 248,27 MW (56,1 % of the summation), and 77,33 MW (17,5 % of the summation) for Gas Turbine, while air compressor recorded 11,8 MW (2,7 %). Profitability analysis shows that the investment criteria are sensitive to change in the price of natural gas. Selling electricity at the current price set by the Nigerian Electricity Regulation Commission (NERC) at zero subsidies and an exchange rate of 365 NGN/kWh is not profitable, as the analysis of the investment gave an infinite payback period. The investment becomes profitable only at a 45 % subsidy regime.

Heliosystem of auxiliary heat supply for a mining enterprise / S. Shkrylova, V. Kostenko, I. Skrynetska

In the conditions of the global ecological crisis in the world and Ukraine, the issue of finding alternative energy sources becomes relevant. One of the most common types of renewable energy is solar energy. In Ukraine today, the most promising direction of using solar energy is its direct transformation into low-potential thermal energy. To get electric power, solar radiation is the mere alternative to electric power generated from mined fuel, and without the pollution of air and water, or adverse consequences manifested in global warming. The disadvantage of this type of installation is the limitation of the duration of light time, as well as the effect of cloudiness. During the day, the number of solar radiation changes, to stabilize it is necessary to accumulate and accumulate it for further use, the technical implementation of stable operation of solar installation due to the use of terrestrial radiation and the accumulator of a specific part of solar energy is proposed. The purpose of the work is experimental studies to ensure the stable operation of the solar collector under cloudy conditions. The paper is aimed at the stabilization of the operation of the solar installation and to obtain additional heat after the Sun's cloud cover. The use of a solar thermal collector is advisable in solar heating and hot water systems in conditions of alternating solar radiation. The results of physical modeling have proved the efficiency of the method of combining types of thermal radiation, due to the accumulation of energy it is possible to increase the quantitative index of solar energy in the conditions of cloudiness by 3 times.

Investigation of parameters affecting underwater communication channel / S. Aydin, T. O. Onur

Underwater communication has become a widely studied area in recent years and showed great potential to be an area of research. Acoustic communication is often preferred in underwater communication due to its suitability for an underwater diffusion environment. However, in underwater communication, the physical and chemical properties of the water environment affect sound propagation. Therefore, determining and examining parameters affecting channel performance in underwater communication plays an essential role in inefficient communication. In this study, the effects of salinity, depth, noise, temperature, and frequency parameters for the underwater channel model are examined. By determining the effects of these parameters on spherical and cylindrical propagation, suitable propagation geometry and parameter values for an efficient channel are investigated. In light of the results obtained, in case of studying in a limited area, the path and absorption losses can be reduced by selecting cylindrical propagation as a geometrical propagation model, thereby an efficient channel model can be formed.

Intensification of paper drying on drying cylinders / V. M. Marchevsky, O. A. Novokhat, V. T. Vozniuk, I. A. Danchyshen

One of the most energy-intensive processes is the drying process. Therefore, an important task is to reduce heat consumption for drying. Various ways to improve the drying devices of paper and cardboard machines are identified. The main disadvantages of these improvements are given. The limiting factor of heat transfer from water vapor to paper is established. The dependence of thermal resistance on the thickness of the condensate layer is given. The authors have developed a new design for condensate drainage. The developed design allows installing movable siphons without replacement of steam inlet heads of the old type (for fixed siphons) with their insignificant modernization and cutting of an annular groove inside the drying cylinder. This will ensure a minimum level of condensate and eliminate the possibility of suction of steam into the condensate return system. Additionally, this will reduce thermal resistance, heat loss, and reduce energy consumption for paper drying as a whole.

Quantification of execution and emission efficiency of a fueled diesel engine / S. Nagendra, B. S. Kumar [et al.]

A significant portion of the automobile and industrial sector is mostly dependent on the running of diesel engines as it is efficient and shifts a large of the goods around the globe and power various equipment. Also, as the use of energy as diesel fuel is increasing enormously with the expansion of industrial growth, diversification, this led to the accelerating global emissions, global climatic change, health issues, and exhaustion of fuels. To succumb this, alternative fuel is needed to fight against the ill effects and as a replacement to diesel fuel. Thus, vegetable oils as alternative fuels are drawing more attention as they are renewable and do not address the problem of greenhouse gas. In the present work, the cottonseed oil was chosen as the favorite among the vegetable oils due to its advantages like less pollutant level, excessive availability, etc. The transesterification process was used to produce the cottonseed oil biodiesel. This research aims to investigate efficiency, emission characteristics by using smooth diesel, cottonseed oil, and mixtures with varying composition from 20 % to 80 % in 20 % steps to identify sustainable fuel as a substitute for existing fuel and to overcome fuel demand and enviro effects. This test was conducted on single-cylinder four-stroke water-cooled diesel engines. From the results, it was revealed that cottonseed oil and its blends have a significant influence on performance and emission characters.

Effect of insert angles on cutting tool geometry / S. V. Shvets, V. P. Astakhov

An analysis of publications has shown that mechanically clamped indexable inserts are predominantly used in modern tool manufacturing. Each insert has its shape and geometry in the tool coordinate system. The static system's required geometry is achieved by the tilting of the insert pocket in the radial and axial directions. Therefore, it is of great importance in the tool design to know the relationships between the insert's geometry parameters in the tool coordinate system where the geometry paraments of the insert are defined and working geometry parameters of the tool defined in the static coordinate system. The paper presents the developed methodology for determining the insert pocket base surface position to ensure the required values of the tool geometry parameters of the selected indexable insert in the static coordinate system. The graphs of the dependence of each of the angles of the insert geometry on the angles of rotation of this insert in the front and profile planes are presented as the level lines for practical use. Using these graphs, one can optimize all geometric insertion parameters in the static coordinate system. The model of the calculations of the mechanism of the insert clamping by a screw is developed. The basic size and tolerance of the output link determine the distance from the intersection line of the base surfaces to the thread axis on the pocket and the minimum amount of the screw stroke on the insert clamping in the pocket.

Contact of working surfaces for spherical washers and recommendations for determining the gap in the joint / I. M. Dehtiarov, A. O. Neshta [et al.]

In article analyzes the technical requirements for spherical washers used in threaded connections of pumps, which made it possible to highlight contradictions in paragraphs of the current standards for pump fasteners. They regarding recommendations for manufacturing technology and control of the working surfaces of washers. Publication analysis in the spherical surfaces lapping showed the absence of research in the spherical surfaces contact after lapping and the dependence of contact parameters by the technological parameters for this operation. The presence of a gap in conjunction with spherical washers after the lapping process was proved geometrically. Its location was determined, and a mathematical dependence was obtained to determine the maximum gap value in conjunction. It was found that the gap depends on the design parameters of the washers' conjunction and the abrasive material grain size used for lapping. Recommendations for selecting the abrasive material grain size for the lapping operation for the most common values of the roughness parameters for the working surfaces of spherical washers have been formed. In the article was proposed to introduce into the technical requirements for the spherical washers drawings changes concerning the gap size allowable in the conjunction, and as well as tolerances value changes of the radii of the working surfaces of the washers, thus increasing their manufacturability without conflicting with the requirements of the current standards.

Ontological tools in anaerobic fermentation technologies: bioinformation database applications / Ye. O. Shulipa, Ye. Yu. Chernysh, L. D. Plyatsuk, M. Fukui

An important direction of forming an effective system for recycling waste of various genesis is to optimize the processes of their treatment using the latest information resources. The paper deals with theoretical studies of directions for the systematization and optimization of anaerobic waste processing technologies using ontological tools based on information resources. Significant scientific support to biochemical research is provided by electronic bioinformatics databases such as KEGG, BacDive, and EAWAG-BBD, etc., which provide access to a collection of graphical representations and text descriptions of metabolic or signal pathways, schemes of regulation of biological processes, information about the organism. They cover various aspects of bacterial and archaic biodiversity, information on microbial biocatalytic reactions and biodegradation pathways of mainly xenobiotic chemical compounds. Also, in the course of work based on analytical data of electronic databases of bioinformatics, in particular, the interaction of necessary ecological and trophic groups of microorganisms, biochemical simulation of anaerobic waste processing with biofuel production was carried out.

Sustainable low carbon urban lighting analysis: a case study of Bandung city / G. S. B. Yusup, R. J. Melda, I. Maman, J. Li

Nowadays, lighting technology is in the transition period from conventional lighting to LED, which more environmentally friendly due to free of harmful substances such as mercury, lead, or other hazardous chemicals and gases. This low light pollution because directional light is carefully distributed precisely to the intended location. Performance of the lights also brighter than other lights. This research measuring the reduction of CO2 gas emissions before and after PJU (street lights) in Bandung is changed from the conventional to the LED, also mapping the CO2 gas emissions in six Development Areas (SWK). The basis for this research approach is a case study with before and after comparison, meaning that this approach only applies to one object that is the same as comparing the condition of the object before and after the treatment. In this study, the evaluation research method used is a causal method, which is a method that is more directed at impact evaluation research. Scientifically and objectively, PJU LED provides low CO2 emissions gas by up to 26 % in Bandung city.

Formation of residual stresses during discontinuous friction treatment / I. Hurey, V. Gurey, M. Bartoszuk, T. Hurey

The tool with grooves on its working surface is used to improve the properties of the strengthened layer. This allows us to reduce the structure's grain size and increase the thickness of the layer and its hardness. Mineral oil and mineral oil with active additives containing polymers are used as a technological medium during friction treatment. It is shown that the technological medium used during the friction treatment affects the nature of the residual stresses' distribution. Thus, when using mineral oil with active additives containing polymers, residual compressive stresses are more significant in magnitude and depth than when treating mineral oil. The nature of the residual stresses diagram depends on the treated surface' shape. After friction treatment of cylindrical surfaces, the highest compressive stresses near the treated surface decreases with depth. And after friction treatment of flat surfaces near the treated surface, the compressive stresses are small. They increase with depth, pass through the maximum, and then decrease to the original values. The technological medium used during friction treatment affects residual stresses in the grains and in the crystal lattice.