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İşletme Sermayesi Finanslama Stratejilerinin Finansal Performans Üzerine Etkisi: Borsa İstanbul Uygulaması
No full textComparative CFD analysis of flow direction in the FDA benchmark nozzle
No full textComputational fluid dynamics (CFD) is a widely used method for analyzing and optimizing blood-contacting medical devices. Standardized CFD methodologies are crucial for modeling physiological flow conditions. Therefore, benchmark models such as the FDA nozzle play an essential role in validating simulations across various flow regimes. This study investigates the effect of two distinct flow directions, as defined by the FDA standard geometry (gradual cone, GC, and sudden contraction, SC), on hemodynamic parameters. Previous studies mainly focused on a single configuration of the FDA nozzle, and no analysis directly compares the GC and the SC under the same experimental conditions. Five different flow conditions, with throat Reynolds numbers from 500 to 6500, were analyzed for both configurations using ANSYS Fluent. Velocity, turbulence intensity, dynamic pressure, and wall shear stresses were computed and compared. Differences in the spatial distribution of peak velocity were observed between the GC and SC configurations. In contrast, lower maximum wall shear stress and dynamic pressure values were observed in the SC configuration. Hemodynamic loads stayed elevated over longer axial distances in the SC, while these peaks were localized more sharply in the GC configuration. These findings demonstrate the effect of flow direction on stress distributions in the FDA nozzle and provide insight into CFD validation and blood damage modeling
Çorum Hasan Paşa Yazma Eser Kütüphanesi'ndeki Fıkıh Eserlerine Dair Bir Araştırma
No full textÇorum yazma eserleri çalışıyor</p
Optimizing OLED efficiency through thermally activated delayed fluorescence: Computational insights into position isomers of BN-perylenes
No full textNext-generation OLEDs require more than just incremental improvements; they necessitate a fundamental rethinking of how excited-state dynamics are controlled. Central to this challenge is the singlet–triplet energy gap (ΔEST), which plays a crucial role in determining whether the abundant triplet excitons are dissipated as heat or harvested as light. When ΔEST decreases below 0.2 eV, reverse intersystem crossing (RISC) occurs with remarkable efficiency. This process unlocks the full potential of thermally activated delayed fluorescence (TADF) without relying on scarce heavy metals. In this context, position isomers of BN-perylenes represent a significant breakthrough. By embedding isoelectronic B–N units at different sites of the perylene scaffold, we can reshape the orbital topology, enhance molecular polarity, and spatially confine excitons. The variation in the position of BN substitution directly tunes ΔEST, allowing for precise control over excited-state energetics and emission behavior. As a result, these isomers produce a new generation of emitters that combine high internal quantum efficiency with long-term stability and color purity. Such molecular innovations transform ΔEST from a passive limitation into an active design variable, marking a significant step toward OLED devices that are brighter, more efficient, and sustainable at scale
