Merkezler / Centershttps://hdl.handle.net/11352/712024-03-29T15:40:52Z2024-03-29T15:40:52ZElectrochemical Corrosion Behaviour of UNS S32205 Duplex Stainless Steel Dependent on Sigma Phase PrecipitationKısasöz, Burçin ÖzbayTütük, İbrahimAcar, SerhatKısasöz, Alptekinhttps://hdl.handle.net/11352/48822024-03-29T11:53:45Z2024-01-01T00:00:00ZElectrochemical 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 ManufacturingTütük, İbrahimUral, Mehmet MoğoltayYılmaz, Mustafa SafaÖzer, Gökhanhttps://hdl.handle.net/11352/48802024-03-22T09:59:44Z2024-01-01T00:00:00ZDevelopment 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.
2024-01-01T00:00:00Zİslam Öncesi ve Sonrası ile Ayasofya Camii Geometrik Desenlerinin Mukayeseli AnaliziSönmez, Serap Ekizlerhttps://hdl.handle.net/11352/48102024-03-15T06:39:48Z2024-01-01T00:00:00Zİslam Öncesi ve Sonrası ile Ayasofya Camii Geometrik Desenlerinin Mukayeseli Analizi
Sönmez, Serap Ekizler
Bu çalışmada Ayasofya Camii’nde yer alan geometrik desenlerin pergel-cetvel (çizgilik) konstrüksiyonu ile çizimine ve
arkalarında yatan geometrik sistemlere odaklanılmıştır. Neredeyse tüm İslam coğrafyasında sayısız örnekle ve özellikle 9.
yüzyıldan sonra daha ileri pergel-cetvel konstrüksiyon bilgisi gerektiren tasarımlarla karşımıza çıkan geometrik desenleri
İslam Dönemi’nin âdeta bir kimliği hâline getiren özellikler vardır. Bilim ve sanatın kesişim kümesinde olan geometrik
desenler, genellikle yapısındaki geometri göz ardı edilerek sadece tespitler üzerinden bilimsel çalışmalara yansımaktadır.
Pergel-cetvel konstrüksiyonu ile bir desenin inşası kaynağını Öklid (MÖ 3. yüzyıl) geometrisinden almaktadır.
Bu çalışmada, geleneğe ait olan bu inşa metodu kullanılarak Ayasofya Camii’nde yer alan desenlerin analizleri yapılmış ve
İslam Öncesi Dönem uygulamaları ile sonrasında ortaya konulan desenler mukayese edilmiştir. Ayasofya özelinde yapılan
bu mukayese ile birlikte genel bir İslam öncesi ve sonrası sürecine dair değerlendirmede bulunulmuştur. Desenlerin
analizinde ilk kez bu makale ile literatüre kazandırılan “nizamî” kelimesine açıklık getirilerek doğru bir konstrüksiyon
için önemine değinilmiştir. Bunların neticesinde genel olarak geometrik desenleri tanımlarken kullanılan başlıklarda
“İslam” kelimesinin yer almasının sebepleri masaya yatırılmıştır. İlave olarak cami minberinde yer alan desenlerin yapısı
üzerinden Ayasofya Camii minberinin tarihlendirilmesine dair bir öneride bulunulmuştur. Bu çalışma ile birlikte sanat
tarihi bağlamında ele alınan geometrik desenlerin analiz boyutu ile bilim tarihi, hatta kültür tarihi yazımı için de bir
vesika değeri taşıyıp taşımadığı sorgulanmıştır.
2024-01-01T00:00:00ZEnhancement of Cytotoxic and Apoptotic Activity Through Oolong Tea Extract-mediated CuO/Cu2O NanoparticlesKarakuş, Emir ErselSert, EsraErol, AyşeKalındemirtaş, Ferdane DanışmanÖzbaş, FatihKarakuş, Selcanhttps://hdl.handle.net/11352/48092024-03-15T06:32:06Z2024-01-01T00:00:00ZEnhancement of Cytotoxic and Apoptotic Activity Through Oolong Tea Extract-mediated CuO/Cu2O Nanoparticles
Karakuş, Emir Ersel; Sert, Esra; Erol, Ayşe; Kalındemirtaş, Ferdane Danışman; Özbaş, Fatih; Karakuş, Selcan
The development of multifunctional nanoformulations with enhanced anticancer activity and drug delivery potential is of increasing scientific importance. In this study, we synthesized and characterized copper oxide nanoparticles mediated by oolong tea extract (OE-CuO/Cu2O NPs) using a variety of techniques, including TEM, XRD, FTIR, and UV–Vis spectroscopy, to assess their physical and chemical properties. Remarkably, the results revealed that OE/CuO NPs exhibited significantly enhanced anticancer activity compared to OE alone. The effects of OE and OE-CuO/Cu2O NPs were on cytotoxicity, apoptosis, and cell cycle progression. Furthermore, we assessed the impact of these nanostructures on CD44/24 antibodies, known as aggressive cell markers, following treatment. The green OE-CuO/Cu2O NPs displayed remarkable inhibitory effects on colon cancer HCT116 and breast cancer cells MCF-7 cells. It was shown that OE-CuO/Cu2O NPs reduced the production of the CD44 antibody, provided cell cycle arrest, and encouraged apoptosis. More specifically, it was discovered that these NPs caused MCF-7 cells to undergo apoptosis and G2/M phase cell cycle arrest. Additionally, drug delivery investigations were conducted to evaluate the potential of OE-CuO/Cu2O NPs as drug nanocarriers, further underscoring their promise in developing novel anticancer agents with significant cytotoxic, apoptotic, and drug delivery properties.
2024-01-01T00:00:00Z