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.

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.

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.

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.

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.

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.

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.

Індекс рубрикатора НБУВ: К663.6-18

Рубрики:

Інші види покриттів металів

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: К748.123.4-56

Рубрики:

Пресування (видавлювання) труб

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: К222.234.043

Рубрики:

Структурні і фазові перетворення в машинобудівній сталі. Теорія термічної обробки

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

The widespread catalysts and nuclear fuel production are the sol-gel technology, including several stages, namely, the raw materials preparation, dispersing it into drops, the granules formation in gas and then in liquid media, granules removal with liquid separation. The vibration granulator is proposed to use on the dispersion stage. One of the problems in their development is determining the vibrational characteristics of a perforated bucket filled with liquid to a certain level. Considering that vibrations are transmitted from the emitter disk through the liquid melt and cause vibrations of the perforated shell, in research, it was decided to use the Fluent Flow and the Transient Structural modules of the ANSYS Workbench software. As a result, numerical simulation results of the emitter disk vibration effect on the cylindrical body are presented. Also, parameters of a discrete mathematical model are evaluated by the bucket vibrations characteristics. The corresponding model considers the inertial, stiffness, and damping properties of functional elements. Additionally, according to the modal analysis results of the priller body, it was determined the eigenfrequencies of the hydromechanical system. Finally, based on the numerical simulation results and their analysis using Fourier transformations, it was determined that the oscillations of the lower part of the bucket, consisting of two harmonic oscillations that equal 230 Hz and 520 Hz.

Індекс рубрикатора НБУВ: Л113.24

Рубрики:

Іонообмінні процеси розділення і очищення

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

The features of improving energy efficiency at a metallurgical enterprise based on portfolio management of energy-saving projects are considered. A simulation model of energy consumption at the metallurgical enterprise, which covers the entire metal products manufacture process, has been developed. The parameters, conduct, and visualization of simulation models of the main equipment such as an electric arc furnace and a ladle furnaces are described. With this software package's help, a comparison of the permissible values and the adjusting of the predicted consumption of active power by a metallurgical enterprise for each fixed point in time are carried out. The system calculates the operating mode regulation range of electric arc furnaces to ensure the continuity of steel casting during melting of a particular steel grade along the appropriate technological routes. The model likewise includes algorithms for transport equipment management that minimize disruptions in continuous casting machines' operation and simulate emergencies. The analysis of the results of energy consumption processes simulation at the metallurgical enterprise is carried out. As a result of modeling, it was possible to increase the productivity of a group of electric arc furnaces and ladle furnaces and reduce the maximum consumption of active power by the metallurgical enterprise. Experimental studies of energy consumption planning methods have been carried out based on real data on the metal products manufacture and electrical energy consumption by the production units of PJSC "Electrometallurgical plant "Dniprospetsstal". The use of the electrical energy consumption model allows in an integrated manner and responds to the dynamics of production processes to carry out further calculations of economic feasibility studies, analysis, and selection of options for the project's implementation of an energy-saving portfolio at the metallurgical enterprise.

Індекс рубрикатора НБУВ: Б112 + Б135

Рубрики:

Законодавчі, адміністративні, соціальні природоохоронні заходи у світі, в Україні

Руйнування озонового шару. Глобальне потепління. Вплив "парникових" газів на біосферу

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

The situation with the processing and disposal of radioactive waste, including the liquid phase, is not resolved. Many questions remain regarding the environmental safety of processes and the technological implementation of the most energy-efficient solutions. Thus, the article's main attention is paid to theoretical studies of the development innovation directions of radioactive waste processing using the VOSviewer software tool. The clusters were formed under modeling directions of application of radiolysis for radioactive waste utilization: the red cluster includes research of radionuclide sorption processes and their concentration for radiolysis of liquid media; the green cluster concerns factors of influence on water radiolysis in hydrogen production; the yellow cluster includes research areas of natural processes related to radiolysis; the blue cluster is connected with mathematical modeling of radiolysis process with fuel production and engineering implementation and the purple cluster related to the processes of radioactive waste management and disposal as well as the application of radiolysis for this purpose. The cluster simulations of nanoparticle and radiolysis applications for radioactive waste treatment have resulted in a new energy recovery strategy. The development of new matrix materials in combination with nanoparticles for the agglomeration and concentration of radionuclides is a promising innovation method improving radiolysis under hydrogen production from radioactive waste.

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.

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.

Індекс рубрикатора НБУВ: З368

Рубрики:

Теплообмінні апарати

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: Л682.024

Рубрики:

Екстракція

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: З361

Рубрики:

Парові котли.Котлобудування

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ