Recep Tayyip Erdoğan Üniversitesi Kurumsal Akademik Arşivi
DSpace@RTEÜ, Recep Tayyip Erdoğan Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Microstructural and mechanical enhancement of AA2024 via multi-pass friction stir processing with HEA (FeNiCrAlCu) particle reinforcement
(Elsevier, 2026) Yanar, Harun; Sekban, Dursun Murat; Özkaya, Serdar; Karabacak, Abdullah Hasan; Aktarer, Semih Mahmut; Coskun, Abdulkadir; Yaylacı, Murat
Friction stir processing (FSP) is an effective solid-state technique for fabricating aluminum-based metal matrix composites (MMCs) with refined and homogeneous microstructures. In this study, HEA (FeNiCrAlCu) powders were incorporated into AA2024 aluminum alloy via multi-pass FSP using 1, 2, and 3-passes. The effects of pass number on microstructural evolution, mechanical properties, tribological behavior, and corrosion resistance were investigated using SEM, XRD, hardness, tensile, wear, and electrochemical corrosion tests. Increasing the FSP pass number promoted progressive fragmentation and more uniform dispersion of HEA particles, as supported by SEM observations and ImageJ-based measurements, resulting in a more homogeneous composite structure. This microstructural improvement directly enhanced the mechanical, wear, and corrosion performance of the composites. For the 3-pass FSPed composite, hardness increased from 155 to 258 HBN, tensile strength from 188 to 246 MPa, and uniform elongation from 3.0 ± 0.5 to 3.6 ± 0.3 mm compared with the base AA2024 alloy. In addition, corrosion current density decreased from 6.94 to 1.36 µA, corrosion potential shifted from − 703 to − 548 mV, and corrosion rate decreased from 14.79 to 3.11 mpy. The 3-pass FSPed composite also exhibited the lowest volumetric wear rate and a more stable friction response.
Crisis-driven cyber risk: Evaluating the cybercrime landscape in the face of pandemic uncertainty
(Elsevier, 2026) Anser, Muhammad Khalid; Ali, Sajid; Chen, Yi; Nazar, Raima
Pandemic-driven uncertainty has been associated with a sharp rise in cybercrime, with opportunistic hackers exploiting new vulnerabilities in remote work environments and digital platforms. The increase underscores the need to implement resilient cybersecurity frameworks to ensure data protection and sustain digital trust. The present investigation analyzes the asymmetric association between pandemic uncertainty and cybercrime across the 10 leading economies having the highest cybercrime rates (USA, China, UK, India, Brazil, Germany, Russia, France, Spain, and Nigeria). In contrast to previous investigations that predominantly employed panel data methodologies and thus disregarded the specific attributes of individual nations, this research uses the innovative Quantile-on-Quantile instrument. It assists in examining the relationships between variables in each distinct country. Consequently, this research provides an in-depth global perspective, offering detailed insights into the distinctive aspects of each nation. The findings disclose a strong positive relationship between pandemic uncertainty and cybercrime, particularly in China, Russia, Nigeria, Brazil, and the USA at higher quantiles of pandemic uncertainty, while in India, Germany, and France, the relationship is more pronounced at higher quantiles of cybercrime. Moreover, the findings confirm asymmetries and variations across different quantiles among the sample countries. The results accentuate the importance of policymakers undertaking comprehensive estimations and developing robust measures to manage deviations in both variables.
A new ultra-fast and sensitive chemosensor based on NIR chromenylium-cyanine molecule modified with thiazole unit for the detection of Hg2+ in real samples
(Elsevier, 2026) Ertuğral, Utku; Aribuga, Hülya; Yavuz, Özgür; Özdemir, Emre; Alcay, Yusuf; Ejder, Nebahat; Yılmaz, İsmail
Since Hg2+ ion contamination constitutes a global threat, the necessity for a rapid, selective and sensitive sensing methods for Hg2+ ions has attracted growing research interest in recent years. Herein, we present the development of a new “ratiometric” and “turn-on” fluorescent probe NIR-12 having absorption and emission properties within the near-infrared (NIR) spectrum. The probe was constructed on a chromenylium cyanine platform decorated with 2-amino-5-bromothiazole for the purpose of efficiently detecting Hg2+ ions in an aqueous medium. Structural analysis of NIR-12 and its interaction with Hg2+ ions were confirmed by several spectrophotometric techniques. The non-fluorescent probe NIR-12 selectively interacted with Hg2+ ions, resulting in a ring opening on the platform. This process led to the generation of strong NIR absorption and emission signals, as well as a substantial color change. Consequently, this enabled the execution of colorimetric analyses. The probe responded to Hg2+ ions very rapidly within 10 s, and exhibited wide linear ranges (1.68-9.81 μM for UV-Vis and 0.85-42.98 μM for fluorescence methods) and remarkably low detection limits for Hg2+ ions (LOD) (0.057 μM (11.40 ppb) for UV-Vis, 0.277 μM (55.53 ppb) for fluorescence). The probe was also applied to real drinking water samples with high recovery ranges (95.13% - 106.62%). The application of smartphone-assisted analysis for Hg2+ ions was thoroughly investigated, demonstrating a linear range between 5.32 × 10−8 M and 9.49 × 10−6 M and a low LOD of 3.42 × 10−6 M.
Endodontic status and oral health in athlete and non-athlete young adults in relation to nutrition and psychological factors
(Nature Research, 2026) Maraş, Edanur; Başar, Özge; Yorgancılar, Nur; Berberoğlu, Gülce; Çakır, Gökhan; Köse, Oğuz
This cross-sectional study aimed to compare highly trained athletes and non-athlete individuals in terms of endodontic status and oral health parameters, considering nutritional and psychological factors. Highly trained athletes (n = 50) and non-athlete individuals (n = 50) aged 18–30 years were included. Clinical examination evaluated the endodontic and periapical status, decay experience (DMF-T), non-carious tooth wear and periodontal indexes. The Oral Health Impact Profile-14 (OHIP-14), Perceived Stress Scale and Mental Well-Being Scale were administered. In addition, daily nutrient elements and potential renal acid load (PRAL) were calculated using a one-year food frequency questionnaire. Comparisons between the groups used the independent t-test/Mann-Whitney U test, Fisher’s exact test and ANCOVA (α = 0.05). Athletes showed higher numbers of teeth requiring endodontic treatment, periapical index scores, decayed teeth, and periodontal index scores compared to non-athletes (p < 0.05). PRAL, organic acid, vitamin D, B vitamins, meal frequency, and mental well-being were also higher in athletes (p < 0.05). Sucrose, carbohydrate, and vitamin C intake had significant effects on endodontic status (p < 0.05). The results revealed that athletes had higher numbers of teeth requiring endodontic treatment, decayed teeth, and periodontal symptoms. Education and prevention programs on oral care and nutrition may help improve their oral health.
Magmatic fertility in post-collisional arcs: contrasting juvenile mafic intrusions and Cu-Mo fertile felsic systems in the Eastern Sakarya Zone (NE Türkiye)
(Elsevier, 2026) Moghadam, Hadi Shafaii; Xiao, Wenjiao; Özen, Sevgi; Mao, Qigui; Miao, Sang
The Eastern Sakarya Zone (ESZ) of northeastern T & uuml;rkiye records a remarkable duality in Eocene magmatism, where Cu-Mo fertile felsic porphyries coexist with barren mafic-intermediate intrusions. We present an integrated, multi-proxy investigation of the I(center dot)spir intrusive complex, incorporating whole-rock geochemistry, zircon U-Pb-Hf isotope-trace element systematics, and apatite major-trace element and in-situ Nd isotopic signatures, to delineate the petrogenetic pathways and magmatic processes that control fertility contrasts across this intrusive suite. Zircon and apatite proxies reveal that I(center dot)spir magmas were derived from a juvenile mantle source, retained consistently radiogenic isotopic signatures, and crystallized under relatively reduced, volatile-poor conditions. In contrast, fertile Eocene felsic intrusions in the ESZ show enriched isotopic signatures, elevated oxidation states, and volatile-rich magmas derived from a metasomatized mantle source and buffered in longlived crustal magma reservoirs, conditions favorable for porphyry Cu-Mo fertility. Apatite-derived estimates of Cl, F, S, and Delta FMQ further distinguish these suites, with fertile magmas showing elevated halogens and sulphur contents coupled with oxidized states favorable for delayed sulphide saturation and metal transport. These results demonstrate that in post-collisional arcs, fertility depends not only on tectonic triggers such as slab break-off or lithospheric delamination but also on whether melts are processed through volatile-charged, oxidized hot zones. The I(center dot)spir suite provides a critical juvenile end-member against which fertile felsic counterparts can be contrasted, offering a refined framework to assess magmatic fertility across the Tethyan Metallogenic Belt and other collisional orogens.
