Yazar "Yagimli, Mustafa" seçeneğine göre listele

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    Analysis of sound wave equations in spherical coordinates using Galerkin weighted residuals method and spherical harmonic functions
    (Gazi Univ, Fac Engineering Architecture, 2024) Karasoy, Taner; Yagimli, Mustafa
    Purpose: In this study, it is aimed to bring an unusual mathematical perspective by using semi-analytical mathematical solution methods, unlike the sound intensity determination formulas available in acoustics, and this scientific approach is supported by numerical data. Theory and Methods: Galerkin Weighted Residues Method (WRM) and Spherical Harmonic Functions, which have been used frequently in sound problems in recent years, are used for the solution of sound wave equations in spherical coordinates, which have not been observed in the literature before, in determining the periodic pressure values of sound.Results: Based on the directivity coefficient and spherical harmonic functions in detecting sound pressure levels in the near field, The Critical Distance Threshold, ??????ini, was defined and combined with data from WRM. It has been observed that the Critical Distance threshold value provides very sensitive results in near field distance calculations. The importance of the number of weight functions of WRM in long distance calculations has especially emerged.Conclusion: The critical distance threshold value has an important place in all mathematical analyzes. In the determination of this value, the effect of spherical harmonic functions and the multiplicity of weight functions are clearly seen.
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    Construction and characterization of a boron-doped surface coating for neutron radiation protection
    (Gazi Univ, Fac Engineering Architecture, 2024) Seval, Hakan Kemal; Yagimli, Mustafa; Tozan, Hakan
    Purpose: This study aims to develop an economic and environmental -friendly, non-toxic boron -doped surface coating material that will provide protection against neutron radiation. Theory and Methods: Shielding is one of the three basic elements of radiation protection. Hexagonal boron nitride (h-BN) is taking great attention in recent years due to its mechanical strength, low cost, thermal conductivity, and resistance to oxidation. Studies also illustrated that it has a high neutron shield performance. Characterization of the proposed coating materials which are formed by adding H-BN filler to polyvinyl butyral (PVB) matrix, was done using XRD and SEM. Radiation experiments were carried out with slow (thermal) neutrons in 241Am-Be isotropic neutron source. A slow neutron activation monitor was used for measurements and the nuclear reaction of the indium element was monitored as a neutron activation monitor. The resulting gamma spectra were evaluated with the Maestro -32 and Gamma Vision32 software. Results: Thermal neutron absorption coefficients (macroscopic cross section) of PVB coating materials formulated with h-BN additive at different ratios were calculated. A homogeneous dispersion was formed by the physicochemical interaction between H-BN and PVB molecules. The analyses of the results illustrate that the macroscopic cross-section value and the neutron radiation blocking feature increase as the ratio of the additive material is increased in the formulation. And also, all coating material samples project the ability to shield thermal neutron radiation. Conclusion: The coating material samples illustrated shielding performance by absorbing thermal neutrons at varying rates. The results of the analyses also possessed that, as the ratio of the additive in the coating material is increased, the neutron radiation blocking feature also increases. However, structural deteriorations are observed on the coating material when the amount of boron is more than 50% by mass. In addition to its easy applicability to various surfaces, the coating material also does not require complex manufacturing processes which provides a great advantage.
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    Development of object detection model for sizing safety measures in Human-Industrial mobile robot interaction
    (Gazi Univ, Fac Engineering Architecture, 2024) Aslan, Tarik; Yagimli, Mustafa
    In human -robot interaction, single -level safety measures are traditionally applied, and employee -specific criteria are not taken into account. However, a new method can be developed using object detection technology, and the risk level of human -robot interaction can be determined by identifying employeespecific criteria such as the use of protective equipment and authorization levels, and different -sized safety measures can be applied depending on the risk magnitude. In this study, YOLOv5n, YOLOv8n, and SSD MobileNet V3 object detection models were developed and analyzed for this purpose. The results show that architectures belonging to the YOLO family run faster and achieve higher levels of accuracy. The YOLOv5n algorithm achieved a speed of 650 FPS with the use of a GPU and an F1 accuracy of 95.7% as a result of the evaluation with test data. The results show that object detection technology has reached an accuracy and speed that can be applied simultaneously with proximity senors, and that industrial mobile robots can detect worker characteristics and rate risks before taking safety measures. This allows for safer working environments, eliminates unnecessary precautions, and optimizes operational efficiency. In addition, this method can be applied in many sectors and areas to provide safe working environments.
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    Evaluating and modeling the effects of brightness on visual attention using multiple object tracking method
    (Taylor & Francis Ltd, 2023) Yazgan, Mehmet Toyanc; Yagimli, Mustafa; Ozubko, Jason
    This article systematically evaluates and models how brightness affects performance in Multiple Object Tracking (MOT) within screen-based environments. MOT proficiency is essential across various fields, and comprehending the elements that impact MOT performance holds significance for occupational health and safety. While previous studies have scrutinized the influence of brightness on object recognition, its repercussions on MOT performance in screen-based environments remain comparatively less comprehended. This research aims to bridge this gap by delving into the distinct and combined impacts of brightness-related factors on MOT performance. Additionally, it seeks to construct a computational model that can forecast MOT performance across diverse brightness conditions. The outcomes of this study will offer valuable insights into core psychological processes, thereby steering the development of more efficient visual displays to enhance occupational health and safety.Our findings revealed a significant correlation between brightness levels and MOT performance, with optimal tracking observed at medium brightness levels. Additionally, complex object motion patterns were found to exacerbate the challenges of tracking in low brightness settings. These insights have direct implications for screen-based interfaces, suggesting the need for adaptive brightness settings based on the content's complexity and the user's task.
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    Investigation of the Dielectric Properties of Graphite and Carbon Black-Filled Composites as Electromagnetic Interference Shielding Coatings
    (Mdpi, 2023) Gumus, Emre; Yagimli, Mustafa; Arca, Emin
    The main purpose of electromagnetic interference (EMI) shielding coatings is the insulation of sensitive devices and protect people from electromagnetic field exposure due to its effects on the human body. This paper investigates the dielectric properties, and electromagnetic shielding performances of graphite and carbon black (CB) filled epoxy matrix composites produced by the mechanical mixing method. The sample compositions were created at rates ranging from 1 to 7 wt%. Samples were analyzed by Vector Network Analyzer (VNA) using the coaxial method in the range of 1-14 GHz, including L band, S band, C band, X band and partially Ku band. After determining the scattering parameters with VNA, AC conductivity, absorption, reflection and total shielding efficiency values were calculated. At high frequencies, almost all the samples showed higher AC conductivity. CB-filled samples show higher AC conductivity than graphite-filled samples. The total shielding efficiency (SET) of the graphite-added samples (19-21 dB) is slightly higher than the carbon black-added samples (8-17 dB). Distinct filling ratios in graphite-added samples result in closer shielding behavior in contrast to carbon black-added samples. However, higher shielding efficiency is observed as the CB filler ratio increases. The shielding efficiencies of the samples with both types of filling materials vary little depending on the frequency. Reflection is the main mechanism of the shielding efficiency, which constitutes the majority of total efficiency for all types of samples.
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    The Time Response Analysis of a Hybrid Electronic Switch and Residual Current Devices System
    (Univ Osijek, Tech Fac, 2024) Yurtcu, Ahmet; Yagimli, Mustafa; Tozan, Hakan
    Residual current devices are vital as they are used to protect humans from electric shocks and fire hazards. These devices detect the residual current in the grid, open the mechanism, and leave the grid without voltage. In this study, the time response of a newly designed hybrid system consisting of an electronic switch system and a residual current device to protect humans from hazards has been analyzed. A model consisting of capacitors and resistors has been used to simulate the human body. In the designed system, the average response time was found to be 1.37 ms, which operates with an average of 6.43 times faster than a conventional residual current device. The results of the study illustrated that the designed system leaves the circuit voltage-free much faster than a conventional residual current device and is more effective in protecting human life.