Journal of Brilliant Engineering (BEN)

Yıldırım ÖZÜPAK

Electronic power transformers (EPT) are transformers that are smaller in size and volume compared to conventional 50 Hz frequency transformers. Medium frequency transformers (MFT) have begun to become important components in high voltage and high power energy conversion systems such as EPTs. In this study, the electric field distribution of these transformers is discussed. The electric field distributions in the transformer have been obtained using the two-dimensional finite element method (FEM). Besides, maximum electric field intensities were obtained in the study. ANSYS@Maxwell simulation program, which realizes a solution based on FEM, was used for these analyzes. Electromagnetic field analyzes of the same transformer under normal conditions were also performed to compare the analyzes. Besides, the values obtained from the high-frequency analysis, the values obtained from the study below 50 Hz frequency, and the values obtained experimentally were compared. In this way, the stress in the insulation material of the transformer and the weak parts of the insulation material were detected. It is expected that the method used will contribute to future studies to examine the results of the electric field distribution analysis of transformers.

https://doi.org/10.36937/ben.2021.003.001

Sunday Edet Etuk Joseph Bassey Emah Ubong Williams Robert Okechukwu Agbasi Inyang Anietie Akpabio

This research paper presents analysis of electrical resistivity values of soots formed by combustion of kerosene, diesel fuel, aviation fuel (Jet A.1), that of kerosene -diesel mixtures at different proportions and that of aviation fuel (Jet A.1)-diesel mixtures at various percentages. The result of the analysis reveals that soot formed by combusting kerosene, diesel, aviation fuel (Jet A.1) and their respective mixtures have electrical resistivity values ranging from 3.516 x 10-1Ωm to 1.836 x 10-1 Ωm with soot from diesel fuel having the lowest value while soot from kerosene has the highest value. The values are within the range of electrical resistivity values for materials classified as semiconductors. Electrical resistivity varies non-linearly with percentage composition of mixture constituents for soot formed by combusting kerosene-diesel mixture or aviation fuel (Jet A.1)-diesel mixture. Soot produced by combustion of pure diesel fuel has less resistivity value, indicating higher conductivity than soot obtained from the burning of aviation fuel whereas soot got from the combustion of kerosene exhibits higher electrical resistivity value than the former. This work has provided a database on the electrical resistivity values of soot (kerosene, diesel fuel, aviation fuel (Jet A.1)) formed as a result of combustion of some fuels and their mixtures for probable utilization by electrical, electronics and petroleum industries. Such database had hitherto not been in existence, hence making this research work a novel.

https://doi.org/10.36937/ben.2021.003.002

Elham Shadkam Reza Rajabi

This research is an attempt to create optimized planning in educational units. The problem of university courses timetabling is one of the problems that is very important for educational units; establishing optimal distances to comply with students' study status as well as balancing other constraints of the timetabling problem is one of the challenges in a timetabling problem. Therefore, sometimes an educational unit may not be able to strike a good balance between all the constraints it faces and fail to achieve a proper timing table. In this paper, in order to achieve optimal exam timetabling with an integer scheduling approach, a model for exam timetabling is presented. The purpose of the proposed mathematical model is to maximize the appropriate time intervals that should be established between students' exams. In this mathematical model, according to the number of allowed exam days and the number of possible exam sessions per day, a number of positions have been considered and it is tried to assign these positions to the courses according to the courses related to the students of each entrance. The most important advantage of the proposed model is its simplicity while sufficient accuracy. Therefore, complex methods are not needed to solve this model.

https://doi.org/10.36937/ben.2021.003.003

Saeed Abbassi Muhammad Kazemi Nima Norouzi Zahra Nasiri

Noise pollution caused by vehicle traffic is one of the major problems in urban areas with road expansion. Due to the increase in the cost of construction and installation of sound walls to deal with noise pollution, to deal with this problem should look for methods that do not have additional costs and operating costs. Improving the pavement texture is one of the most effective ways to reduce tire noise and pavement and reduce the asphalt surface’s sound. To evaluate the slip resistance of asphalt, the English pendulum test according to ASTM E303-74 standard was performed on wet parts of asphalt in wet conditions. This device is used to examine the fine texture of the pavement. The number of pavement friction with a negative coefficient of 0.1469 has an inverse ratio with the intensity of sound level increases the number of pavement friction aligned with the amount of sound level created decreases. On the other hand, the depth of pavement texture, which is determined as the size of pavement materials, with a coefficient of 0.2810, has a direct ratio with the amount of noise pollution, and the smaller the number of fine-grained materials used will increase the sound level. According to the results of the coefficients estimated from the equation, it can be concluded that the preparation of pavements with an amount of friction can reduce the amount of noise pollution emitted by the movement of vehicles, especially in urban areas and sensitive areas. Therefore, it is recommended that in acoustically sensitive areas, in preparing pavements, arrangements be made to use coarser materials and maintain proper pavement resistance. For this purpose, in this article, the pavement’s texture is examined in the amount of noise created due to the tire’s interaction and the pavement.

https://doi.org/10.36937/ben.2021.003.004

Kadri Vefa EZİRMİK Furkan Kalan

Structural steels are among the most widely used materials in today's industry. Various surface coating processes are used to protect structural steels from corrosion in atmospheric or aggressive environments. The most commonly used method is the galvanizing process based on forming zinc coating on the steel surface by using the hot dip method. Zinc coatings are insufficient to protect against corrosion, especially in chlorinated environments. Aluminum and its alloys stand out as an alternative material group to zinc in chlorinated environments. In this study, aluminum and aluminum alloy coatings, which are thought to be an alternative to zinc coating, were coated on the structural steel surface using the hot dip method. To examine how different aluminum alloys affect the corrosion and high-temperature oxidation properties of steels, nearly pure AA1050, high Cu content AA2024, and high Mg content AA5083 alloys were coated on structural steels. The coating process was carried out by dipping the structural steels into molten aluminum baths kept at a constant temperature of 700°C for 1, 3, and 5 minutes. The optimum adhesion and surface properties were obtained from dipping time for 3 minutes. The properties of coatings and intermetallic structures formed at the coating-steel interface were examined using an optical microscope, X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM), and Energy Scattering Spectroscopy (EDS) systems. To examine the high-temperature oxidation properties of the coatings, the coated samples were oxidized for 24 hours at 750°C under open-air conditions, and the changes in weight were investigated. Immersion corrosion tests were performed in 3.5% NaCl solution, and corrosion losses and degradation patterns were investigated. As a result of the studies, it has been determined that the Al coatings produced by the hot dip process significantly increase the oxidation and corrosion resistance of the structural steels.

https://doi.org/10.36937/ben.2021.003.005