Browsing by Author "Karaköse, Ercan"

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Investigation of the performance and properties of ZnO/GO double-layer supercapacitor
(ELSEVIER, 2024) Büyükkürkçü, Handan; Durmuş, Ali; Çolak, Hakan; Kurban, Rifat; Şahmetlioğlu, Ertuğrul; Karaköse, Ercan; 0000-0002-0277-2210; AGÜ, Mühendislik Fakültesi, Bilgisayar Mühendisliği Bölümü; Kurban, Rifat
Composite electrode material was formed by mixing reduced graphene oxide (rGO) and zinc oxide (ZnO) compound, using the Hummers and green synthesis methods, respectively. Of rGO powder, 10 g was mixed with 10%, 20% and 30% ZnO, and composite electrodes were obtained by using 10% binder. The energy storage performance and structural characteristics of the supercapacitor were evaluated by analyzing the capacitance values of the synthesized electrodes. The structural characterization of ZnO/rGO composites was performed using X-ray diffraction and field-emission scanning electron microscopy. The electrochemical properties of the ZnO/GO electrodes were analyzed by cyclic voltammetry, electrochemical impedance and galvanostatic charge–discharge tests. The specific capacitance value of electrodes increased as zinc content increased in the ZnO/rGO composite material used to produce electrodes. The maximum specific capacitance values were measured at 5 mV/s scanning rate as 194.23 (rGO), 366.81 (10% ZnO), 383.18 (20% ZnO) and 410.48 F/g (30% ZnO). In conclusion, the use of composite material formed by the combination of ZnO nanoparticles obtained by green synthesis method from orange peel and graphene oxide increased the electrochemical efficiency of the supercapacitor.
Investigation of the structural and magnetic properties of rapidly solidified Nd–Fe–B–Ce alloys
(SPRINGER LINK, 2024) Aytekin, Orkun; Kurban, Rifat; Durmuş, Ali; Çolak, Hakan; Karaköse, Ercan; 0000-0002-0277-2210; AGÜ, Mühendislik Fakültesi, Bilgisayar Mühendisliği Bölümü; Kurban, Rifat
This study introduces the frst literature report of rapidly solidifed Nd–Fe–B– Ce alloys fabricated using the melt-spinning technique at varying disc rotation speeds. The resulting alloy images are then analyzed using various image processing techniques, and their structural and magnetic characteristics are described. The alloys are characterized using a variety of methods, including x-ray difraction (XRD), feld-emission scanning electron microscopy (FE-SEM), energy-dispersive x-ray spectroscopy (EDX), diferential thermal analysis (DTA), vibrating sample magnetometry (VSM), and Vickers microhardness tests. By using XRD, the tetragonal hard magnetic Nd2Fe14B phase is detected in the Nd30Fe65B0.9Ce5 alloy. The FE-SEM microstructure analysis shows that the grain structure of the ingot alloy is indistinct, and the tetragonal symmetric structure begins to appear at disc rotation speeds of 20 m/s and 40 m/s. The analysis of FE-SEM images using histogram analysis, the image segmentation technique, and VSM method reveals that the coercivity values of the sample produced at the 80 m/s solidifcation speed increased by approximately 34% when compared to the ingot alloy.
Multi-focus image fusion by using swarm and physics based metaheuristic algorithms: a comparative study with archimedes, atomic orbital search, equilibrium, particle swarm, artificial bee colony and jellyfish search optimizers
(SPRINGER, 2023) Çakıroğlu, Fatma; Kurban, Rifat; Durmuş, Ali; Karaköse, Ercan; 0000-0002-0277-2210; AGÜ, Mühendislik Fakültesi, Bilgisayar Mühendisliği Bölümü; Kurban, Rifat
The lenses focus only on the objects at a specific distance when an image is captured, the objects at other distances look blurred. This is referred to as the limited depth of field problem, and several attempts exist to solve this problem. Multi-focus image fusion is one of the most used methods when solving this problem. A clear image of the whole scene is obtained by fusing at least two different images obtained with different focuses. Block-based methods are one of the most used methods for multi-focus fusion at the pixel-level. The size of the block to be used is an important factor for determining the performance of the fusion. Thus, the block size must be optimized. In this study, the comparison between the swarm-based and physics-based algorithms is made to determine the optimal block size. The comparison has been made among the following optimization methods which are, namely, Archimedes Optimization Algorithm (AOA), Atomic Orbital Search (AOS) and Equilibrium Optimizer (EO) from the physics-based algorithms and Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC) and Jellyfish Search Algorithm (JSA) from swarm-based algorithms. The swarm-based ABC and JSA algorithms have shown a better performance when compared to physics-based methods. Moreover, meta-heuristic algorithms, in general, are more adaptive compared to the traditional fusion methods.