EUREKA: Physics and Engineering

CALCULATION OF THE INSTANT MODEL OF SOLAR RADIATION DISTRIBUTION ON CURVED SURFACES IN HIGH-RISE BUILDINGS

Olga Krivenko — 2020-11-30

The aim of research is to simulate the zones of solar radiation on the curved surfaces of the shells of high-rise buildings for the effective use of renewable solar energy. An urgent task is the development of tools that can substantiate the decision-making by designers about the location of solar thermal devices in the energy-efficient design of curvilinear high-rise buildings. The main attention is paid to high-rise buildings, is actively growing in modern megalopolises and requires a significant energy resource. To optimize the integration of solar thermal devices in high-rise buildings, it is important to take into account a set of design parameters, including parameters of surface shape and location in space. A feature of curved surfaces, considered in the study, is their aerodynamic properties, which provide them with the advantage of choosing among modern high-rise buildings. At the same time, the complexity of setting the parameters of a curved surface to determine the zones of solar radiation for the effective use of regenerative solar energy lies in providing reliable and convenient tools for optimizing decision-making.

The study proposes an application of the method based on a discrete geometric model of solar radiation input on the surface of the shells of high-rise buildings, described by compartments of curved geometric surfaces. As a result of modeling, let’s obtain a family of lines of the same level of solar radiation on a certain curved surface for the given parameters of time and geographic location. As an example of simulation modeling, the performed calculations of the instantaneous model of the distribution of solar radiation on the compartments of the curved surfaces of an ellipsoid of revolution, hemisphere, hyperbolic paraboloid. On the basis of the proposed model for the distribution of solar radiation over curvilinear surfaces of buildings, the influence of factors arising in the design process is investigated: changes in the geometric parameters of the surface shape, orientation to the cardinal points, the formation of zones of its own shadow on surfaces. Calculations were performed and instantaneous solar radiation zones were constructed on the surfaces of a hemisphere, a hyperbolic paraboloid with various geometric parameters, taking into account different orientations relative to the cardinal points, and determining the zones of its own shadow.

At this stage of the study, the result is an algorithm for constructing zones of different levels of solar radiation on curved surfaces of high-rise buildings. The advantage of the algorithm is the ability to analyze the results of changes in the design parameters of the surface of a high-rise building when placing solar systems on them. The proposed approach will provide a basis for automating the modeling process, will help expand the scope of solar systems in high-rise construction and increase the efficiency of their work

IMPROVEMENT OF THE ELECTRICAL PROPERTIES OF SYNTHETIC LIQUID DIELECTRIC FOR PULSE CAPACITORS

Maya Yadigar Abdullayeva — 2020-11-30

An increase in electricity generation is possible not only through the construction of power plants, but also through the creation of fundamentally new energy sources. One of the problems of modern electrical engineering is to ensure the reliability of the operation of capacitors at electric field strengths exceeding I50-200MV. In the domestic and foreign capacitor industry, for heavy pulse modes, castor oil (CO) is used as a liquid impregnation. The development of a method for producing a substitute for natural castor oil, which is a universal impregnating liquid in capacitors, is an urgent problem in the electrical industry. Thus, we have developed a method for the production of acetoxymethyl-w.hexyl-o-xylene, the electrophysical properties of which make it possible to use it as an environmentally friendly and promising substitute for natural castor oil. However, there was a problem of stabilization, since compounds of the ester type have (as impregnating liquids in capacitors) a disadvantage, which consists in their sensitivity to light hydrolysis and atmospheric effects. Ester exhibits high stability with respect to air up to 200 °С, therefore, inhibition by the addition of antioxidants is required is not new.

In this work developed the basic electrophysical properties of the ester-acetoxymethyl-secondary hexyl-o-xyleole; methods for its purification and stabilization. There were chosen the adsorption method of thermo-oxidative stabilization to clean dielectric fluid from conductive impurities.

As a result of the electrophysical characteristics of the acetoxymethyl-secondary hexyl-o-xyleole ester, as well as the method of its purification using alumina, and hydrogenation on a catalyst representing 0.2 % palladium on alumina and stabilization using additives NG-2246. As a result of the research, it was possible to obtain an ester with improved electrophysical parameters

CONSTRUCTING THE PARAMETRIC FAILURE FUNCTION OF THE TEMPERATURE CONTROL SYSTEM OF INDUCTION CRUCIBLE FURNACES

Dmitriy Demin — 2020-11-30

The objects of the study were diagnostic features that allow determining the quality of controlling temperature modes of induction crucible melting. For this, in the normalized space of feature factors, which are the content of SiO₂ and FeO+Fe₂O₃in slag, a discriminant function is constructed and a decision rule is obtained in the form of a linear classifier, which allows determining in which mode the process was carried out. It is shown that this rule is the basis for identifying an event qualified as a parametric failure, and it can be included in the general structure of the parametric failure function.

The parametric failure function constructed for the temperature control system of induction crucible melting makes it possible to ascertain that the control system does not meet the specified requirements for a specific temperature mode of melting. The mechanism of inferencing regarding the occurrence of a parametric failure based on this function is as follows. If the decision rule showed that the object belongs to the “low-temperature mode” class, although the process under these conditions should have been carried out in the high-temperature mode, a parametric failure is recorded. In this case, the numerical value of this function takes the value of “1”, otherwise – “0”. The inferencing mechanism works similarly if, on the basis of the decision rule, it is revealed that the process was carried out in the high-temperature mode, although under these conditions it should have been carried out in the low-temperature mode.

Based on the constructed parametric failure function, practical problems related to planning maintenance of the temperature control system integrated into the melting complex or organizational and technical measures aimed at minimizing violations of the melting regulations can be solved

OPTIMIZATION OF RECTIFICATION PROCESS USING MOBILE CONTROL ACTION WITH ACCOUNT FOR CRITERION OF MAXIMIZING SEPARATION QUALITY

Anton Sheikus — 2020-11-30

The use of mobile control action allows the improvement of technical-economical characteristics of the rectification process and allows for operation regimes that can’t be achieved with traditional control approaches. Mobility lies in the ability to choose the movement law of compound source and energy in the spatial region of apparatus.

Mobile control over the rectification process can be realized by changing the column feed point. An optimal number of feed trays must be determined with consideration of cost and output performance, and also the quality of the target product.

The work aimed to develop a method for calculating optimal control action, including mobile ones, on the rectification process with additional account for the criterion of maximizing quality of target product, and also, comparison of static column profiles that are optimal by different criteria.

Mathematical modeling of the rectification column for separation of water-methanol mixture revealed that increasing quality requirements to target products decreases the number of the optimal feed tray. A method was described for process optimization by the normalized criterion that accounts for separation quality and power consumption. The method was used to determine optimal values of traditional (flows of heat into the column's cube and phlegm) and mobile (feed tray number) control actions that provide the best technical-economical parameters of the rectification column.

A proof is presented for the existence and uniqueness of solutions for this optimization problem and the effectiveness of using mobile actions for different requirements to target. The optimal temperature profile of the culms was studied and their characteristic features that correspond to different specific and normalized optimization criteria were found

STUDY OF THE DYNAMIC LOADING OF THE LOAD-BEARING STRUCTURE OF A FLAT WAGON DURING TRANSPORTATION BY SEA

Oleksij Fomin — 2020-11-30

To increase the efficiency of combined transportation, the supporting structure of flat wagon has been created. A feature of the wagon is that the sections have a low center of gravity. This solution allows for the transportation of oversized cargo on a flat wagon within the established dimensions. The design of this flat wagon can be used for the carriage of goods not only by main lines, but also in rail and water traffic when transported by rail ferries.

To ensure the safety of transportation of a flat wagon with containers on a railway ferry, their dynamic loading was determined. It is taken into account that a large-capacity container of 1AA standard size is placed on each section. The solution of the mathematical model was carried out in the MathCad software package. The resulting accelerations, as components of the dynamic load, were taken into account when determining the stability of a container on a flat wagon during transportation by a rail ferry. It was found that the stability of the container is ensured at tilt angles up to 25°.

A computer simulation of the dynamic loading of the supporting structure of an articulated flat wagon with containers during transportation by a railway ferry has been carried out. The calculation is implemented in the CosmosWorks software package using the finite element method. The fields of distribution of accelerations relative to the supporting structure of the flat wagon and containers are determined. The maximum percentage of discrepancy between the results of mathematical and computer simulation does not exceed 11 %.

The research carried out will contribute to the creation of innovative designs of flat wagons, as well as to increase the efficiency of the operation of combined transport in international traffic

IMPLEMENTATION OF OPTIMUM ADDITIVE TECHNOLOGIES DESIGN FOR UNMANNED AERIAL VEHICLE TAKE-OFF WEIGHT INCREASE

Sven Maricic — 2020-11-30

The aim of this paper is to investigate the possibility of drone optimization by selecting and testing the best material suitable for additive manufacturing technology and generative design approach, i. e. shape optimization. The use of additive manufacturing technology enables the creation of models of more complex shapes that are difficult or impossible to produce with conventional processing methods. The complex and unconventional design of the drone body can open up many possibilities for weight reduction while maintaining the strength of the drone body. By using 3D printing in addition to FEM (Finite Element Method) analysis, and generative design it can identify areas of the drone body that are overdrawn, allowing it to either lift off material or simply change the design at these areas. Choosing the right material for this application is crucial in order to optimise the mechanical properties of the material with weight, material cost, printability and availability of the material and the 3D printing method, while at the same time reducing environmental pollution. The goal is to reduce the drone mass by 15–20 % using generative design tools. Mass is an important segment when prototyping a drone. If the drone is too heavy, more lift power is needed to keep the drone in the air, so the propellers have to turn faster and use more energy. Consequently, the reduction of drone mass should increase the take-off weight. In this article 5 commercial drones of similar characteristics are compared with the final proposal of our 3D printed drone (Prototype 1). The rotor distance between the drones, the weight of the electric motor and the take-off weight are compared. The goal was to produce a prototype with a big rotor distance-to-weight ratio, and take-off weight bigger than observed drones have.

The defined goal function was optimized in order to evaluate characteristics of 12 different 3D printed materials. Following properties: ultimate strength, stiffness, durability, printability of the material, and required bed and extruder temperature for printing were taken in consideration to select optimal material. Polycarbonate proved to be the best choice for 3D printing UAVs

STRESS ANALYSIS SIMULATIONS OF WELDED AND BOLTED JOINTS METHOD FOR FULL STEEL AND COMPOSITE-STEEL CHASSIS STRUCTURE OF ELECTRIC LOW FLOOR MEDIUM BUS

Sudirja Sudirja — 2020-11-30

Stress analysis of welded steel-to-steel, bolted steel-to-steel, and bolted composite-steel chassis in an electric low floor medium bus structure is presented in this paper. The analysis was carried out on the condition that is when the bus is full of load in idle/static. This condition reflects the situation of the vehicle in full load with passengers and components, which is important to be analyzed to anticipate the unwanted structural failure of the chassis. Finite Element Method (Harmonic response simulation) is used to investigate the structural behavior of both welded and bolted methods. Several parameters such as 2 Hertz for the maximum frequency, 5000 kg for the total vehicle weight, and the uniform distribution of load are used for this study to simulate the simplified, real application in the real world. The first comparison is between the welded and bolted steel-to-steel chassis which results in the bolted method has a lower stress value by the difference of 4.3 MPa in the joint section than the welded joint. This means that the bolted joint is more recommended than welded for the use as an electric low floor medium bus and has the potential to be optimized further. In terms of reducing the weight of the chassis structure, then lightweight material (carbon fiber composite) is used to replace the full steel chassis to be a composite-steel chassis. The use of this hybrid material depicts the stress value of 61.5 MPa in the joint area, this value is still far below the limit of carbon fiber that is 3200 MPa makes this bolted composite-steel is considerably safe in full load condition as an electric low floor medium bus structure. Using this hybrid bolted composite-steel chassis structure also reduces the total chassis weight by about 22.7 % compared to the full steel chassis structure, thus one could expect to extend the mileage of electric vehicles by more than 20 %

DEVELOPMENT AND OPTIMIZATION OF AN ULTRA WIDEBAND MINIATURE MEDICAL ANTENNA FOR RADIOMETRIC MULTI-CHANNEL MULTI-FREQUENCY THERMAL MONITORING

Mikhail Sedankin — 2020-11-30

The article is devoted to the development of a printed ultra-wideband miniature antenna that can be used for microwave radiometry. An antenna design with a ring-shaped radiator has been proposed, which provides reception of microwave radiation from biological tissues in the 1800–4600 MHz range. The results of mathematical modeling of the antenna electromagnetic field in biological tissues using the finite difference time domain (FDTD) method are presented. Optimization of the antenna design has been carried out to ensure acceptable matching parameters and optimal antenna functionality. The developed antenna has a height of 6 mm and a calculated mass of 5 g; it is planned to manufacture a dielectric substrate based on PDMS polymer with the addition of barium titanate. The issues of calculating the antenna parameters (measurement depth, resolution and distribution of radiation power over the volume of biological tissue, sensitivity, etc.) are considered. The research results and design parameters of the developed antenna demonstrated the effectiveness of the new antenna and the possibility of its adaptation to the object of research. Considering the presence of an ultra-wide band and miniature dimensions, the antenna can be a sensor of a multi-frequency multi-channel microwave radiothermograph

FEATURES OF FINDING OPTIMAL SOLUTIONS IN NETWORK PLANNING

Olena Domina — 2020-11-30

The object of research is a test network diagram, in relation to which the task of minimizing the objective function q_max/q_min→min is posed, which requires maximizing the uniformity of the workload of personnel when implementing an arbitrary project using network planning. The formulation of the optimization problem, therefore, assumed finding such times of the beginning of the execution of operations, taken as input variables, in order to ensure the minimum value of the ratio of the peak workload of personnel to the minimum workload.

The procedure for studying the response surface proposed in the framework of RSM is described in relation to the problem of optimizing network diagrams. A feature of this procedure is the study of the response surface by a combination of two methods – canonical transformation and ridge analysis. This combination of methods for studying the response surface allows to see the difference between optimal solutions in the sense of "extreme" and in the sense of "best". For the considered test network diagram, the results of the canonical transformation showed the position on the response surface of the extrema in the form of maxima, which is unacceptable for the chosen criterion for minimizing the objective function q_max/q_min→min. It is shown that the direction of movement towards the best solutions with respect to minimizing the value of the objective function is determined on the basis of a parametric description of the objective function and the restrictions imposed by the experiment planning area. A procedure for constructing nomograms of optimal solutions is proposed, which allows, after its implementation, to purposefully choose the best solutions based on the real network diagrams of your project

RESEARCH ON THE MANUFACTURING MAGNESIUM FROM THANHHOA DOLOMITE BY PIDGEON PROCESS

Quyen Vu Viet — 2020-11-30

The magnesium and magnesium alloys has applied widely in different industrial aspects in Vietnam in the modern life. Especially, the products from magnesium alloys implementing in the automotive have increased rapidly since the car elements tend to be generated by the light alloys in order to save the fuel. However, in the current time, Vietnam has no factories to produce the magnesium to adapt the domestic demand although it owns an enrich resource of raw materials. This research indicates the possibility of using the dolomite ore in Thanhhoa – Vietnam to make the magnesium as well as evaluate the primary factors like recovering temperature, reducing agent rate, recovering time having effect on the reduction efficiency of Thanhhoa dolomite by metallothermic method in vacuum (Pidgeon Process). This is basic process, low investment and suitable for the small and medium scales in Vietnam. The experiment includes heating, indicating the chemical ingredients and recovering experiment on the dolomite after calcination (dolime) by using ferrosilicon. The thermodynamic model is created to estimate the recovering efficiency in the Pidgeon. The result shows that the CaO/MgO molar ratio of calcination dolomite in Thanhhoa is nearly 1.5 which is suitable to produce magnesium in the case of highly-required efficiency and pureness. Besides, the result from the furnace of the experiment is lower than the one in the model. The samples are set up to check the influence of the rate of ferrosilicon in the compound. The result indicates that the ideal efficiency reaches 85 % with 30 % ferrosilicon. Moreover, the study confirms that the optimal operating conditions in this process are recovering during three hours at 1200 °C and 100 Pa pressure. This result proves the potential application of Thanhhoa dolomite in the industry suitable with the current condition in Vietnam

STUDY OF THE BEHAVIOURS OF SINGLE-PHASE TURBULENT FLOW AT LOW TO MODERATE REYNOLDS NUMBERS THROUGH A VERTICAL PIPE. PART I: 2D COUNTERS ANALYSIS

Akeel M. Ali Morad — 2020-11-30

This study presents a model to investigate the behavior of the single-phase turbulent flow at low to moderate Reynolds number of water through the vertical pipe through (2D) contour analysis. The model constructed based on governing equations of an incompressible Reynolds Average Navier-Stokes (RANS) model with (k-ε) method to observe the parametric determinations such as velocity profile, static pressure profile, turbulent kinetic energy consumption, and turbulence shear wall flows. The water is used with three velocities values obtained of (0.087, 0.105, and 0.123 m/s) to represent turbulent flow under low to moderate Reynolds number of the pipe geometry of (1 m) length with a (50.8 mm) inner diameter. The water motion behavior inside the pipe shows by using [COMSOL Multiphysics 5.4 and FLUENT 16.1] Software. It is concluded that the single-phase laminar flow of a low velocity, but obtained a higher shearing force; while the turbulent flow of higher fluid velocity but obtained the rate of dissipation of shearing force is lower than that for laminar flow. The entrance mixing length is affected directly with pattern of fluid flow. At any increasing in fluid velocity, the entrance mixing length is increase too, due to of fluid kinetic viscosity changes. The results presented the trends of parametric determinations variation through the (2D) counters analysis of the numerical model. When fluid velocity increased, the shearing force affected directly on the layer near-wall pipe. This leads to static pressure decreases with an increase in fluid velocities. While the momentum changed could be played interaction rules between the fluid layers near the wall pipe with inner pipe wall. Finally, the agreement between present results with the previous study of [1] is satisfied with the trend