http://dspace.beu.edu.tr:8080/xmlui/handle/123456789/15609 2026-04-23T06:52:36Z 2026-04-23T06:52:36Z Onat, Erhan http://dspace.beu.edu.tr:8080/xmlui/handle/123456789/16330 2025-10-23T07:33:01Z 2025-03-26T00:00:00Z

Caffeine Coated Iron Oxide Crustacean for Ammonia Borane Dehydrogenation Development of Magnetic Nickel Nanoparticles Onat, Erhan The aim of this study was to develop nickel (Ni) nanoclusters with caffeine-coated magnetic iron oxide (Fe3O4) center shells for the catalytic hydrolysis of ammonia borane (AB). In the study, magnetic iron oxide (MIO) clusters were obtained by hydrothermal treatment. These clusters were first coated with caffeine according to the reflux method at 150 oC for 12 hours, and then Ni was decorated on these clusters by impregnation method. Magnetic Ni catalyst (Ni@C/Fe3O4) was synthesized by dropping 10 M 20 mL sodium borohydride (NaBH4-SBH) into the Ni-C/ Fe3O4 magnetic nanoclusters in solution as a result of the loading processes carried out at room conditions. After filtration, washing and drying in nitrogen atmosphere, the crumbled catalyst was identified by advanced identification techniques (FT-IR, BET, SEM, EDX, XPS) and used in AB hydrolysis. The solvate medium, catalyst amount, AB concentration, temperature and repeated use parameters were investigated for AB catalytic hydrolysis. As a result of the optimization at 303 K, the best hydrogen production was determined as 7873 mL/g.min using 2.5 % NaOH, 30 mg catalyst and 300 mM AB. The catalyst cycle frequency (TOF) was measured as 1447 s-1. As a result of reaction kinetics investigations, it was determined that the reaction was 1st order and the reaction activation energy was 35.07 kJ/mol.

2025-03-26T00:00:00Z Sarı, Ali Nemutlu, Ömer Faruk http://dspace.beu.edu.tr:8080/xmlui/handle/123456789/16329 2025-10-23T07:30:11Z 2025-03-26T00:00:00Z

Seismic Performance of the Kahramanmaraş Earthquakes: Ground Motion Prediction Models and the Role of Vertical Components Sarı, Ali; Nemutlu, Ömer Faruk On February 6, 2023, two very large earthquakes occurred in Türkiye. These earthquakes occurred on the Eastern Anatolian Fault, one of the most active fault zones in Türkiye. After two earthquakes occurred 9 hours apart, with Pazarcık (7.7 Mw) and Elbistan (7.6 Mw) epicenters, 11 cities of the country were directly affected by the earthquake. In addition to a significant number of casualties, structural damage caused by the earthquake occurred. Ground motion prediction equations (GMPEs), in short, are used to estimate the impact/value that the acceleration/velocity/spectral parameters etc. of a wave moving from an earthquake source can create in a study area. With the help of these attenuation relations, various earthquake parameters can be estimated depending on distance. In this study, the peak ground acceleration (PGA) values obtained from the stations taking measurements during the Kahramanmaraş earthquakes were examined using 6 different attenuation relations valid for Türkiye. In the study, data from 105 different stations measured during the Kahramanmaraş earthquake were used. In addition, the vertical earthquake effect caused by the earthquake was evaluated in terms of Turkish seismic code conditions. Looking at the study results; The approach of ground classifications, the fact that the acceleration values of the Kahramanmaraş earthquake remained above the curves of the attenuation relations and the failure to consider different earthquake characteristics have shown that the current attenuation relations are weaknesses. It has been observed that earthquake data deviate in a certain distance region in all attenuation relations. The GMPEs generally did not show high agreement with the Kahramanmaraş earthquake data. For this reason, the situations that should be taken into consideration when preparing a new decay relationship are examined. Finally, it was concluded that the higher-than-expected vertical earthquake effects were not assessed correctly in the code and therefore the vertical acceleration spectra given in the code should be updated.

2025-03-26T00:00:00Z Yıldırım, Muhammed Yalçın, Sercan Karaduman, Mücahit http://dspace.beu.edu.tr:8080/xmlui/handle/123456789/16328 2025-10-23T07:26:31Z 2025-03-26T00:00:00Z

Classification of Malicious Network Dataset With Residual CNN Yıldırım, Muhammed; Yalçın, Sercan; Karaduman, Mücahit In this study, a model on network security is proposed and a method is suggested for data protection, integrity, and communication continuity. Network security is becoming more and more important every day as the digital world develops. It is aimed at classifying the data labeled as good and bad in the ready dataset. In the proposed model, first of all, all the information in the dataset is digitized. Then, it is normalized to the range of 0-1 and made ready as an input to the proposed architecture. It is aimed to classify the information in this two-class dataset with the proposed Residual CNN architecture. The accuracy rate obtained after the training and testing stages of the model is 94.9%. This accuracy rate shows that the proposed model successfully results in the detection of malicious packets in network attacks and can be used for network security.

2025-03-26T00:00:00Z Köksal, Koray Tambağ, Fatma http://dspace.beu.edu.tr:8080/xmlui/handle/123456789/16327 2025-10-23T07:21:22Z 2025-03-26T00:00:00Z

Optical Faraday manipulating longitudinal component of optical vortex beams Köksal, Koray; Tambağ, Fatma In this study, we aim to investigate the novel application of the Optical Faraday effect in manipulating the longitudinal component of optical vortex beams, which are characterized by their unique orbital angular momentum and helical phase structure. The Optical Faraday effect, induced by the interaction of a magnetic field with a specific optical crystal, results in a rotation of the polarization plane of light. This phenomenon is harnessed to exert precise control over the longitudinal component of optical vortex beams, a feature not typically present in conventional light beams. Our theoretical analysis explores the modulation of the longitudinal component, revealing a significant influence on the beam’s polarization characteristics, intensity distribution, and phase characteristics. This manipulation breaks new grounds for increasing the precision of optical systems, with potential applications in advanced optical communication, high-density data storage, and quantum information processing. The findings show that by finely tuning the magnetic field and material properties, it is possible to achieve a new kind of control mechanism over the propagation and interaction of optical vortex beams. This work paves the way for further exploration into the dynamic control of structured light, offering promising prospects for future photonic technologies.

2025-03-26T00:00:00Z