Sürdürülebilir Kalkınma Amaçları

• 3
• 1

Araştırmacılar(4)

• Ekinci, Ali Ercan
• Karadeni̇z, Sibel Morkoç
• Tuzluca Yesilbag, Fatma Nur
• Yesilbag, Yasar Ozkan

• ArticleAçık Erişim2024/r/ebyu/19720
  Synthesis of Tungsten Disulfide on B-N-Doped Carbon Nanotubes to Enhance the Electrochemical Performance of Supercapacitors

  Yeşilbağ, Yaşar Özkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih

  In this research, boron and nitrogen-doped carbon nanotubes (B-N-CNTs) were synthesized at 900°C using the FCCVD method. Carbon, nitrogen, and boron as source materials were simultaneously introduced using a batch- mode droplet reactor and ferrocene as a catalyst. B-N-CNTs were obtained with diameters ranging from 10 - 50 nm and lengths around 30 – 80 μm. These B-N-CNTs were thoroughly characterized and structurally analyzed. Subsequently, tungsten disulfide (WS2) nanosheets on B-N-CNTs were synthesized using the hydrothermal method to design a composite material and were investigated as electrodes for supercapacitors. The morphological properties of B-N-CNT@WS2 were determined by various analytical techniques such as XRD, FESEM, XPS, and EDS. B-N-CNT@WS2 was investigated as an electrode for supercapacitors in two- and three-electrode cells. In the three-electrode cell, B-N-CNT@WS2 exhibited a specific capacitance of 320 F g−1 at a current density of 0.5 A g−1, while the two-electrode cell showed a capacitance of 41 F g−1. The symmetric supercapacitor at a current density of 5 A g−1 exhibited excellent structural stability by preserving 90% of its specific capacitance after 9000 cycles in the 1 V potential range.

  • 
  İncele
• ArticleAçık Erişim2024/r/ebyu/19648
  The effect of Aluminum (Al) ratio on the synthesis of the laminated Mn2AlB2 MAB Phase

  Yeşilbağ, Yaşar Özkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih

  MAB phases have recently garnered significant interest due to their excellent properties, such as high thermal and electrical conductivity, oxidation resistance, and exceptional corrosion resistance. Although the Mn2AlB2 phase has been synthesized using multiple methods recently, it requires long experimental durations (up to 7 days), high costs, and extensive experimental efforts to achieve high purity. In our study, the Mn2AlB2 MAB phase was synthesized using Al, B, and Mn as precursor materials. Specifically, we investigated the effect of Al ratios (Al:1.3, Al:3, and Al:10) on the formation of the Mn2AlB2 MAB phase. The precursor powders were mixed homogeneously in stoichiometric ratios using ball milling and cold-pressed in a 1-inch die set to form green pellets, which were then sintered in a high-temperature vacuum furnace at 1200°C. The resulting Mn2AlB2 MAB phase were characterized in terms of crystal structure, impurity, and microstructure using XRD, FESEM, and EDS.

  İncele
• ArticleAçık Erişim2022/r/ebyu/20652
  Large-area synthesis of vertically aligned carbon nanotubes growth on the aluminum foil via FCCVD method

  Yeşilbağ, Yaşar Özkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Demirez, Eda Nur

  In this study, VA-CNTs were synthesized homogeneously on Al foil at 610 oC temperature by Floating Catalyst Chemical Vapor Deposition (FCCVD) method in a horizontal tube furnace. While ethanol was used as the carbon source, ferrocene was used as the catalyst. VA-CNTs with diameters in the range of ~10-15 nm and lengths in the range of ~30-35 µm were obtained. Structural and morphological analyzes of VA-CNTs were determined using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersion X-Ray Spectroscopy (EDS), Raman Spectroscopy and X-Ray Photoelectron Spectroscopy (XPS). These VA-CNTs, synthesized by the FCCVD method on an Al foil in a large area, have the potential applications to be used especially in energy storage, optoelectronic, and sensor.

  İncele
• ArticleAçık Erişim2021/r/ebyu/20875
  Novel Synthesis of Good Electrochromic Performance $WO_3$ Nanoplates Grown on Seeded FTO

  Karadeniz, Sibel Morkoç

  Tungsten trioxide $(WO_3)$ has applications in various electrochromic devices and is fabricated using various techniques, which affect its electrochromic properties. In this study, tungsten trioxide $(WO_3)$ nanoplates were synthesised via a two-step facile synthesis process using a hydrothermal technique on seeded fluorine-doped tin oxide (FTO) glass substrates. $WO_3$nanoplates with high porosity were obtained using a fast and simple hydrothermal method. First, a seed layer was grown on FTO using a spin coating process. $WO_3$ nanoplates were then quickly synthesised on the seeded FTO glass using a hydrothermal technique at 200 ̊C for 1h. The nanoplates were characterizated by using XRD, SEM, Chronoamperometry and Cyclic Voltammetry techniques. The$WO_3$ nanoplates have got a crystal structure mixed monoclinic and hexagonal phases. The crystal grain sizes of the film was found to be 36 and 53 nm for the (011) and (200) sharpest crystal planes of monoclinic and hexagonal crystal phases respectively. The switching times of $WO_3$ nanoplates were determined as 1.28 s for colouration and 5.50 s of bleaching, and the diffusion coefficient was calculated as 4.2×10-10 cm2/s. As a result, the nanoplate structures with high porosity were successfully obtained and the $WO_3$ nanoplates showed good electrochromic performance with a good crystal structure, high diffusion coefficient, and short ion insertion time.

  İncele
• ArticleAçık Erişim2020/r/ebyu/20934
  Two-step synthesis of MnCo2S4 nanowires for supercapacitor electrode

  Yeşilbağ, Yaşar Özkan

  In this study, MnCo2S4 nanowires were synthesized on 3D-Ni foam by the hydrothermal process in two-step and investigated as supercapacitor electrode material. Crystal structure and morphology analyzes of MnCo2S4 nanowires were performed. Electrochemical measurements were taken in 1 M of a potassium hydroxide aqueous electrolyte solution. The specific capacitance value calculated from GCD measurement taken at a current density of 0.5 A g−1 from the sample was 450 F g−1 . Furthermore, the sample have good cycling stability by keeping 46% of the initial specific capacitance after 3000 cycles.

  • 
  İncele
• ArticleAçık Erişim2020/r/ebyu/20933
  Investigation of Flower-like ZnCo2O4 Nanowire Arrays Growth on 3D-Ni Foam as Supercapacitor Electrode Material

  Yesilbag, Fatma Nur Tuzluca

  As a supercapacitor electrode material, flower-like ZnCo2O4 nanowire (NW) arrays were directly grown on 3D-Ni foam using the hydrothermal method. Structural and morphological analysis of the electrode material was characterized by XRD, FE-SEM, and EDS, while its electrochemical analysis was characterized by CV, GCD, and EIS. The electrode material demonstrated excellent electrochemical performance with a maximum areal capacitance of 1.01 F cm-2 at a current density of 0.5 mA cm-2 . After 2.000 charge-discharge cycles, the electrode showed excellent cycle stability, having 72% of the initial areal capacitance.

  • 
  İncele
• ArticleAçık Erişim2019/r/ebyu/22346
  Effect of Molar Concentration on Structural, Morphological and Optical Properties of CdO Thin Films Prepared by Chemical Bath Deposition Method

  Karadeniz, Sibel Morkoç

  Cadmium Oxide (CdO) thin films were grown on Indium Tin Oxide (ITO) coated glasses by Chemical Bath Deposition (CBD) technique. The concentration of aqueous bath was varied between 0.03 M and 0.05 M. The films were annealed at 400 °C for 2 h. Structural, morphological and optical properties of the CdO thin films were investigated with XRD, SEM and Uv-Vis measurements. Additionally, the hydrophobic and hydrophilic nature of the films were studied with the water contact angle (WCA) measurements. The CdO thin films showed cubic crystal phase diffraction peaks in the spectra. The surface of CdO thin films changed from prism-like morphology to network-like (nano- fibrous) morphology with increasing concentration. The optical band gaps of thin films were calculated between 3.816-3.857 eV by Uv-Vis spectra. The Prisma- like morphology exhibited maximum transmittance above 65%. Nature of the CdO thin film surface changed from hydrophobic to hydrophilic, depending on changing morphology with increasing the precursor concentration.

  İncele
• ArticleAçık Erişim2019/r/ebyu/22230
  SEM, XRD ve EDX yöntemleriyle insan aort kapaklarında kalsiyum mineralizasyon analizi

  Yesilbag, Yasar Ozkan; Ates, Azman

  Kalsifik aort darlığı, kalsiyum mineral birikimi ile yavaş ilerleyen bir hastalıktır. Literatürde aort kapağındaki yapısal kusurları araştırmak için çeşitli çalışmalar bildirilmiştir. Bununla birlikte, bugüne kadar, aort kapağının dokusundaki kireçlenme oluşumunun morfolojik yapısı hakkında çok az şey bilinmektedir. Bu çalışmada, aort kapağında morfoloji ve kalsifikasyon yapısal analizi yapılmıştır. Aort kapak dokusunda biriken kalsifikasyon yapılarının morfolojisini belirlemek için taramalı elektron mikroskopisi (SEM) kullanılmıştır. SEM tarafından gözlemlenen morfolojik yapıları karakterize etmek için Enerji Dağılımlı Xışını Analizi (EDX) ve X-ışını Difraktometresi (XRD) kullanılmıştır. Sonuçlar, eser elementlerin kalsifikasyon oluşum sırasında çekirdeklenmede rol oynayabileceği ortaya koyulmuştur.

  • 
  İncele
• Conference ObjectYalnız künye2009/r/ebyu/18310
  Seasonal Variation or Indoor Radon in Artvin-Turkey

  Fildisis, Takis; Yesilbag, Y. O.; Küçükömeroglu, A.; Kurnaz, A.; Özderya, F.

  Indoor radon studies have been conducted in Artvin, Eastern alack sea region of Turkey using SSNTD type nuclear track dedector (CR-39). Radon measurements were done for 4 seasons in 73 dwellings, selected as uniformly distributed as possible. The radon concentrations vary from 21 aq m(-3) to 321 aq m(-3) with the annual mean concentration of 132 aq m(-3) for Artvin Seasonal variation indoor radon shows high in winter low values in summer. The resulting estimated annual effective dose-equivalent due to inhalation of radon for inhabitants is 3.32 mSv y(-1) and the total annual effective dose lies in the range of the action level (3-10 mSv y(-1)) recommended by the ICRP

  İncele