Yazar "Demir, Bunyamin" seçeneğine göre listele

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    Öğe
    Study on crystallographic and electronic structure of micrometre-scale ZnO and ZnO:B rods via X-ray absorption fine-structure spectroscopy
    (Int Union Crystallography, 2021) Erat, Selma; Ozkendir, Osman Murat; Yildirimcan, Saadet; Gunaydin, Selen; Harfouche, Messaoud; Demir, Bunyamin; Braun, Artur
    X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectra were recorded to investigate the electronic structure and local crystal structure of ZnO and ZnO:B powders produced via hydrothermal synthesis. ZnO and ZnO:B grow as micrometre-scale rods with hexagonal shape, as confirmed by scanning electron microscopy micrographs. The number of broken ZnO:B rods increases with increasing B concentration, as observed in the images, due to B atoms locating in between the Zn and O atoms which weakens and/or breaks the Zn-O bonds. However, no disorder within the crystallographic structure of ZnO upon B doping is observed from X-ray diffraction results, which were supported by EXAFS results. To determine the atomic locations of boron atoms in the crystal structure and their influence on the zinc atoms, EXAFS data were fitted with calculated spectra using the crystal structure parameters obtained from the crystallographic analysis of the samples. EXAFS data fitting and complementary k-weight analysis revealed the positions of the B atoms - their positions were determined to be in between the Zn and O atoms.
  • [ X ]
    Öğe
    Turkey's energy transition from fossil-based to renewable up to 2030: milestones, challenges and opportunities
    (Springer, 2021) Erat, Selma; Telli, Azime; Ozkendir, Osman Murat; Demir, Bunyamin
    The energy demand of Turkey has been increasing along with increasing life standards and population and growing economy particularly since the 1980s. Most of the oil and natural gas have been imported by Turkey due to insufficient domestic reserves. Nowadays, the population of Turkey is about 83 million. The Turkish economy grew by 3% in the last 30 years and became the 18th largest economy in the world and the 6th one in Europe. Turkey aims to use energy resources efficiently, effectively and eco-friendly. Concerning climate change, Turkey signed the Paris Agreement and pledged a 21% reduction in greenhouse gas emission by the year 2030. While the energy world is in an inevitable transition to green energy, Turkey, which has a huge potential to achieve 100% energy transition in renewable energy, is still the 17th largest country in the utilization of renewable energy. Although Turkey has already reached the 2023 targets concerning the utilization of renewable energy, there is a long path to reach the target of reducing greenhouse gas emissions. The 2030 targets of Turkey are to increase the installed solar capacity up to 38,000 MW, wind capacity up to 25,000 MW and geothermal capacity up to 4000 MW. Turkey officially announced that the utilization of renewable energy will be 32%. However, taking into account the potential and success in 2023 targets, it was seen that 2030 targets should be revised and increased from 32% to at least 50%. This study presents the milestones, challenges and opportunities of Turkey on the way of the energy transition toward renewable up to 2030. The energy goals of Turkey which are to use domestic energy resources efficiently and effectively were discussed and presented in detail. The aim of Turkey is to reduce the energy import dependency (76%). The installed energy capacities, energy consumption and projections, energy security and energy policies of Turkey were also presented. [GRAPHICS] .