Scopus İndeksli Yayınlar / Scopus Indexed Publications
https://hdl.handle.net/11352/3471
Scopus İndeksli Yayınlar koleksiyonuna ait yayınları içerir.2024-03-29T15:13:58ZElectrochemical Corrosion Behaviour of UNS S32205 Duplex Stainless Steel Dependent on Sigma Phase Precipitation
https://hdl.handle.net/11352/4882
Electrochemical Corrosion Behaviour of UNS S32205 Duplex Stainless Steel Dependent on Sigma Phase Precipitation
Kısasöz, Burçin Özbay; Tütük, İbrahim; Acar, Serhat; Kısasöz, Alptekin
In this study, the microstructure and electrochemical corrosion behavior of the UNS S32205 alloy were investigated. Firstly, the phase diagram of the studied samples was determined by Thermo-Calc 2022 software, and the solution treatment temperature was designated. The studied samples were cooled by various cooling rates following the solution treatment at 1050 °C for 30 min. The samples were characterized by optical microscope, scanning electron microscope, and XRD analysis. Also, electrochemical corrosion behavior was investigated by potentiodynamic polarization, cyclic potentiodynamic polarization and electrochemical impedance spectroscopy analyses. Microstructural examinations revealed that decreasing cooling rate causes the precipitation of the sigma phase, and the ratio of the sigma phase was increased up to 29 % by the decreasing cooling rate. Furthermore, it was determined that precipitation of the sigma phase reduces the Epit values, and the sample with the highest amount of sigma exhibits the lowest corrosion resistance. On the other hand, presence of the sigma changed the electrochemical impedance spectroscopy behavior of the UNS S32205 and double-layered model fit the results.
2024-01-01T00:00:00ZDevelopment of an Alternative Heat Treatment to the Traditional T6 Heat Treatment of AlSi10Mg Alloy Produced by Additive Manufacturing
https://hdl.handle.net/11352/4880
Development of an Alternative Heat Treatment to the Traditional T6 Heat Treatment of AlSi10Mg Alloy Produced by Additive Manufacturing
Tütük, İbrahim; Ural, Mehmet Moğoltay; Yılmaz, Mustafa Safa; Özer, Gökhan
In this study, alternative solution heat treatments, applied at lower temperatures and shorter times, were
applied to AlSI10Mg samples produced with the powder bed laser fusion technique. Thermocalc software
was used to determine the temperatures of the NT6 solution heat treatment. The samples were analyzed by
optical microscope, scanning electron microscope, energy-dispersive x-ray analysis, x-ray diffractometer
and their mechanical behavior was examined. The results were compared with traditional T6 heat treatments
and it was determined that the samples showed better ductility after NT6 heat treatments while
maintaining the strength values in the traditional method.
2024-01-01T00:00:00ZA Bi-Objective Traffic Signal Optimization Model for Mixed Traffic Concerning Pedestrian Delays
https://hdl.handle.net/11352/4879
A Bi-Objective Traffic Signal Optimization Model for Mixed Traffic Concerning Pedestrian Delays
Akyol, Görkem; Silgu, Mehmet Ali; Çelikoğlu, Hilmi Berk; Göncü, Sadullah
Urban traffic networks suffer in numerous ways from traffic congestion. Some of these adverse effects are increased travel times
of cars, buses, bicycle users, pedestrians etc., with the addition of excessive greenhouse gas emissions. Transportation engineers
and policy makers try to improve the quality of urban transportation systems by developing projects to enhance the pedestrian
experience, reduce private car usage, reduce total time spent in the network through different control strategies, and diminish the
detrimental effects. In this context, this study takes Connected and Automated Vehicles (CAVs) and pedestrians into account at
signal-controlled intersections. A novel intersection signal control optimization methodology that incorporates pedestrian delays
and vehicular emissions from CAVs is presented. Non-dominated sorting genetic algorithm-II is utilized to solve the multiobjective
optimization problem. For the emission calculations, the MOVES3 emission model is utilized. The proposed framework is tested
on real-world case study. Simulation experiments showed major improvements in pedestrian delays and lower emissions.
2024-01-01T00:00:00ZExplosive Behavior in COVID-19 and Policy Responses: Lessons Learned for Public Health Management
https://hdl.handle.net/11352/4811
Explosive Behavior in COVID-19 and Policy Responses: Lessons Learned for Public Health Management
Gündüz, Lokman; Aysan, Ahmet Faruk; Bağcı, Rıfgı Buğra; Karahan, Hatice
Since the first case of COVID-19 in Turkey, there has been a lingering question as elsewhere in the world: ‘‘When will or
should the government impose severe restrictions to protect public health?’’ From a public health perspective, there is value in
developing a model to support proactive implementation of social policies. This study aimed to show the benefits of using a
novel econometric test (the Generalized Supremum Augmented Dickey-Fuller Test) to detect explosive behavior (bubbles) in
Turkey’s daily COVID-19 cases and deaths. Results from the analysis demonstrated a link between identified explosive episodes
and critical public health decisions, especially in the case of daily new deaths. They also showed a negative relationship
between the formation of exuberant behavior during the pandemic and the vaccination rate. Public health policymakers can
incorporate this method into their arsenal to evaluate the overall health situation in combating the pandemic and respond
accordingly. Furthermore, among the lessons learned from the Turkish experience is the importance of having a coronavirus
scientific advisory board in the decision-making process and the ability to promptly implement policy measures.
2024-01-01T00:00:00Z