Sürdürülebilir Kalkınma Amaçları

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Araştırmacılar(5)

• Balcı, Muharrem
• Başoğlu, Mehmet
• Çiftci, Okan
• Demir, Kurtuluş
• Meral, Hilal Şebnem

• MakaleAçık Erişim2026/r/gumushane/19439
  Modeling and Performance Analysis of Continuously Variable Series Reactors (CVSR) for Congestion Management in Meshed Distribution Networks

  Ciftci, Okan; Tomsovic, Kevin; Ozkan, Gokhan

  Distribution systems, particularly in densely loaded urban areas, frequently experience transformer overloading during peak consumption hours. Rather than resorting to costly infrastructure reinforcement or complex Flexible AC Transmission Systems (FACTS), this paper proposes a cost-effective optimization and control approach utilizing a Continuously Variable Series Reactor (CVSR). Unlike FACTS devices that rely on expensive power electronics, the CVSR capitalizes on magnetic core saturation to regulate reactance, offering a robust solution at a fraction of the cost (~$10/kVAr). The CVSR regulates the reactance on the primary side of the transformer via magnetic core saturation to control power distribution among transformers. In this study, the steady-state framework of the CVSR is derived and integrated into power flow formulations. The proposed model is validated using a two-parallel transformer system and tested on the heavily meshed IEEE 342-Node Low Voltage Networked Test System (LVNTS). Simulation results demonstrate the CVSR effectively relieves transformer overloading by redistributing power flow, thereby enhancing system flexibility and allowing utilities to avoid or defer extensive grid upgrades.

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  İncele
• MakaleAçık Erişim2026/r/gumushane/19406
  NdBCO/YBCO/MgO ince film çekirdek kullanılarak TSMG yöntemiyle üretilen eklenmiş halka tipi YBCO külçe süperiletkeni

  Çakır, Bakiye; Basoglu, Mehmet; Aydıner, Alev; Duman, Şeyda; Batur, Kübra Nur

  Bu çalışmada NdBCO/YBCO/MgO (300 nm NdBCO/ 20 nm YBCO/ MgO) ince film çekirdeği ile üstten aşılama-eritme-büyütme [Top-Seeded-Melt-Growth (TSMG)] yöntemi uygulanılarak 32 mm çapında Y123 + %25 Y211 (YBCO) örnekleri ile Y123 + %25 Y211 + %20 Ag2O (YBCO-Ag2O) ekleme örneği üretildi. Üretilen üç adet YBCO örneği, YBCO-Ag2O ekleme örnekleri ile c-ekseni yönünde üst üste istiflenerek eklendi. Eklenmiş örnek su jeti kullanılarak süperiletken halka haline getirildi. Manyetik özelliklerini gözlemlemek için örneğin farklı bölgelerinden alınan kesitlerin manyetizasyon ölçümleri yapılarak kritik akım yoğunluğu değerleri hesaplandı. Yapısal özelliklerini gözlemlemek için X-ışını analizi ve polarize optik mikroskop görüntüleri alındı. Büyütme işlemi için kullanılan NdBCO/YBCO/MgO ince film çekirdekleriyle başarılı tek kristal örnekler üretildi. Elde edilen halka tipi örnekte, ek bölgelerden kesit alınan örneklerin, ana örneklere kıyasla daha kararlı bir manyetizasyon davranışı sergilediği görüldü.

  İncele
• MakaleAçık Erişim2025/r/gumushane/14311
  Superconducting Properties of Welded Three Top-Seeded YBa2Cu3O7−x Produced with NdBCO/YBCO/MgO Thin-Film Seed

  Batur, Kübra Nur; Duman, Şeyda; Çakir, Bakiye; Başoğlu, Mehmet; Aydiner, Alev

  This study investigates hollow single-crystal top-seeded melt growth (TSMG) YBa2Cu3O7−x (YBCO or Y123) samples welded with Ag-added TSMG YBCO solder materials produced using NdBCO/YBCO/MgO thin-film seeds. Three main samples and one solder material are produced by the TSMG method. In order to increase the dimensions of the bulk YBCO superconductor, two slices of the solder material and the main samples are stacked on top of each other with the c-axis parallel and welded at 1030 °C. X-ray diffraction patterns, polarized optical photographs, and SEM micrographs are taken to determine the structural properties of the samples. A preferential orientation in the c-axis is observed with a good connection. Low-temperature resistance and magnetization measurements are made for the specimens taken from the welding region. A sharp superconducting transition occurs at 0 T around 93 K for welding regions of W-ab and W-bc specimens. The critical current densities (Jc) are high as in the main samples. At the same time, the Jc values at 77 K and 0 T are found as 1.54 × 104, 1.98 × 104, 2.21 × 104, 2.31 × 104, and 2.36 × 104A cm−2 for the W-a, W-ab, W-b, W-bc, and W-c specimens, respectively. The single-grain feature is not impaired; thus, the absence of additional grain boundaries facilitates the current passage.

  İncele
• MakaleYalnız künye2025/r/gumushane/11700
  Impact of erbium doping on critical current density and constituent phase in BSCCO superconductors

  Açikel, S.; Cumhur, I.; Öztürk, A.; Başoğlu, M.; Düzgün, I.

  This work systematically examines the influence of partial substitution of calcium (Ca) by erbium (Er) on the structural integrity and superconducting performance of Bi2Sr2Ca2Cu3O10+δ (BSCCO) high-temperature superconductors. Samples were synthesized through the conventional solid-state reaction method and characterized via X-ray diffraction, scanning electron microscopy, resistivity, and magnetization measurements. Despite the close effective ionic radii of Er and Ca, experimental results revealed that increasing Er content led to a deterioration of the superconducting phase and the emergence of semicon ducting characteristics. Quantitative analyses demonstrated a notable reduction in critical current density (Jc), with undoped BSCCO samples exhibiting approximately 14% higher Jc values under equivalent conditions. These findings suggest that while ionic size considerations may permit Er substitution from a stoichiometric perspective, the structural and superconducting phase stability of the BSCCO matrix is adversely affected by Er incorporation.

  İncele
• MakaleYalnız künye2024/r/gumushane/13934
  Identification of wart treatment evaluation by using optimum ensemble based classification techniques

  Balcı, Muharrem; Alkan, Ahmet

  Warts caused by Human Papilloma Virus (HPV) do not disappear spontaneously with the body's natural immunity. This is due to many features of HPV, such as its weak immune effect, not entering the bloodstream and causing an immune response, and permanent infection of skin cells. HPV requires urgent treatment due to these characteristics and the fact that warts are most common on the hands and feet and are painful and disturbing. Choosing the most appropriate Cryotherapy or Immunotherapy treatment methods according to the patient's physiological characteristics is important in order to carry out the treatment process quickly. This study focuses on helping experts choose the most appropriate treatment for the most common plantar and common warts. For the selection of treatment method machine learning have been used. Bagged Tree and Subspace K-Nearest Neighbors (KNN) Ensemble classification algorithms were developed and tested on two data sets. These data sets were used to develop classification algorithms with pre- and post-treatment information of 180 patients receiving cryotherapy and immunotherapy treatments. The Subspace KNN Ensemble algorithm correctly predicted the treatment results of 88 of 90 patients receiving cryotherapy treatment, reaching 97.80% accuracy, and the Bagged Tree Ensemble algorithm correctly predicted 78 out of 90 patients receiving immunotherapy, reaching 86.7% accuracy. It has been shown that algorithms can help experts in terms of both high accuracy values ​​and fast decision making. The algorithms proposed have not been used before, and it has also been seen that they have superior performances than similar studies.

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  İncele
• MakaleYalnız künye2023/r/gumushane/14392
  The effect of the Y2O3 buffer layer on the microstructural and physical properties of melt-processed Y358 superconductor

  Başoğlu, Mehmet; Çakir, Bakiye; Duman, Şeyda; Aydiner, Alev

  The Y3Ba5Cu8O18 (Y358) superconductors were produced using the Melt-Powder-Melt-Growth (MPMG) method. In the crystal growth process, Y2O3 powder was used as a substrate in both powder and tablet form. The first sample was produced without using any buffer layer, the second sample was produced with a powdered Y2O3 buffer layer, and the third sample was produced with a tablet-form Y2O3 buffer layer. The effect of the Y2O3 substrate on the structural and physical properties of the Y358 superconductor samples was investigated. Superconducting phases were observed in all samples of Y358 through XRD measurements, confirming their presence. Samples fabricated using the powder and tablet forms of the Y2O3 substrate had a better microstructure than the sample fabricated without a Y2O3 substrate. The highest critical current density (J c) value was obtained at 77 K for the Y358 sample produced with a Y2O3 powder substrate, and the J c value was calculated as 1.2 × 104 A cm–2 according to the Bean model.

  İncele
• MakaleYalnız künye2023/r/gumushane/12586
  The effect of fabrication method on physical properties of different Y211 and 20% Ag2O added YBCO sample

  Duman, Şeyda; Çakır, Bakiye; Başoğlu, Mehmet; Küçükömeroğlu, Tayfur; Aydıner, Alev

  In this study, it is aimed to investigate the effects of production methods on the physical properties of 20% Ag2O and different ratios of Y211 added YBCO samples. In this context, the samples with Y123 + x % (x = 20, 25, 30) Y211 + 20%Ag2O compositions were fabricated by MPMG and TSMG methods in two groups to join YBCO main samples. XRD measurements were performed to determine the characteristic peaks. Trapped magnetic fields and vertical levitation forces between the bulk samples and a permanent magnet were measured using a computer-controlled system in ZFC at 77 K. From the XRD measurements, it was found that MPMG YBCO samples had a dominant superconducting structure and partially showed orientation peaks in the c-axis direction, while TSMG YBCO samples were single-crystal samples oriented along the c-axis. From the trapped magnetic field measurement results, the trapped magnetic field value of the Y123 + 25%Y211 + 20%Ag2O (TAg25) sample prepared by the TSMG method was higher than that of the other samples. Among the levitation force measurement results, the maximum repulsive force values of TAg25 and TAg30 (Y123 + 30%Y211 + 20%Ag2O) samples are the highest. At the same time, the hysteresis widths of these samples are also the highest, which proves that their flux-pinning potential is higher than that of the other samples.

  İncele
• MakaleYalnız künye2021/r/gumushane/14641
  The Effect of Grain Growth Temperature on the Trapped Magnetic Field of Y358 Superconductors

  Başoğlu, M.

  In this study, three different Y358 samples were produced by the melt-powder-melt-growth (MPMG) method at different maximum grain growth temperatures of 1030 °C, 1040 °C, and 1050 °C. The differential thermal analysis (DTA), X-ray powder diffraction (XRD), magnetic levitation force, trapped magnetic field values and magnetization measurements were performed. According to the results, the highest magnetic levitation force, the highest critical current density and the highest trapped magnetic field values were obtained from the sample produced at the temperature of 1050 °C.

  İncele
• MakaleAçık Erişim2017/r/gumushane/11360
  The effect of sintering in different atmospheres on superconductivity parameters of YBCO

  Başoǧlu, Mehmet

  YBa2Cu3O7 (Y123) is a superconductor material discovered in 1987 and its transition temperature is above the liquid nitrogen temperature. It is known that superconductor samples produced by the solid-state reaction route are very often sintered in air atmosphere. However, in the presented work, Y123 was prepared by the same technique using a sintering ambient composed of a mixture of oxygen and argon gases for the first time. Critical current densities of the samples were calculated using results of magnetization measurements. It was obtained from magnetization analysis that all the samples exhibited superconductor character. It was also observed that the sample sintered in the 50% oxygen and 50% argon atmosphere showed the highest critical current density.

  İncele
• MakaleYalnız künye2014/r/gumushane/11883
  Improvement of Coercivity and Curie Temperature of Sintered Nd-Fe-B Permanent Magnets by Addition of Cu and Ni

  Başoğlu, M.; Yanmaz, E.

  Sintered Nd-Fe-B magnets are some of the strongest magnetic materials showing magnetic properties. Blending addition is frequently performed in order to improve the magnetic properties of these materials. In this work, high-melting point Ni and low-melting point Cu were added to Nd15Fe77B8 ingot by blending. As a result of structural analysis, it was observed that 0.2 wt% Cu + Ni addition improved the structure of the material; on the other hand, excessive addition resulted in porosity. It was also observed that 0.2 wt% addition improved the magnetic properties, and Curie temperature increased with increasing addition ratio.

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