WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 2Citation - Scopus: 2Tuning the Solid Phase Fluorescence Emission From Long Wavelength Visible To Near-Infrared in Oxazol-5 Derivatives: Structure–property Relationship, Theoretical and Experimental Studies(Springer, 2023) Nazlı, İbrahim Hanif; Yakalı, Gül; Topkaya, Derya; İzmirli, Merve; Uzun, Sema Demirci; Alp, SerapMost of the fluorescent molecules among organic π-conjugated materials show blue or green emission in the solid phase but few of them emit red-shifted visible and near-infrared light in the material science. To create molecules emitting for this feature, two π-conjugated oxazol-5-one derivatives containing donor (OCH3) and acceptor groups (NO2) were synthesized. Their optical and charge-transport properties were investigated through experimental and theoretical methods including the single crystal X-ray crystallography, Hirshfeld Surface Analysis, photophysical studies and Density Functional Theory (DFT), respectively. In addition, FT-IR, 1H-NMR, 13C-NMR spectroscopy, cyclic voltammetry (CV) measurements were performed. According to our results, both molecules may provide the significant pathway of development of long wavelength visible and red emissive features in solid phase with the aggregation induced enhanced emission (AIEE) properties particularly in the fields of OLEDs, optical communication, defence and bioimaging.Article Citation - WoS: 1Citation - Scopus: 1Thermodynamic Re-Assessment of a Geothermal Binary Power Plant Operated in a Moderate-Temperature Geothermal Field(Inderscience, 2023) Özcan, Zeynep; Gökçen Akkurt, GüldenAn existing organic rankine cycle power plant which uses isobutane as working fluid is re-evaluated for different working fluids. The plant is first modelled by EES software; then the model is simulated for different working fluids obtaining heat transferred through the heat exchanger, net work output, energy and exergy efficiencies, and mass flowrate of the working fluid. Two parametric studies are conducted to evaluate the thermodynamic performance of the plant under a range of turbine inlet temperature (130°C–155°C) and geothermal resource temperature (152°C–161°C) for each working fluid. The study reveals that the highest cycle energy and exergy efficiencies are observed for R-152a at any geothermal resource temperature. R-152a resulted with 13.1% and 58.2% cycle energy and exergy efficiency, respectively at operation condition, whilst the lowest efficiency and net work output is calculated under n-butane presence.Article Citation - WoS: 2Citation - Scopus: 2Assessment of Future Water Demand in a Semiarid Region of Turkey: a Case Study of Tahtali–seferihisar Basin(Springer, 2023) Karahan, S. M.; Elçi, ŞebnemWater is a vital resource for society and nature, and its scarcity has consequences in all aspects of existence. Today, issues including the inability to preserve the status of existing water resources and excessive water withdrawal are causing the amount of water to diminish day by day. Furthermore, factors such as urbanization and industrialization, population growth, water quality degradation owing to agricultural pesticides, and climate change, all have a negative impact on water supplies. A basin-based water management analysis was carried out in this study by applying the "Integrated Water Resources Management" strategy to the Tahtalı–Seferihisar sub-basin in Turkey, where water stress is expected in the future. Using the WEAP (Water Evaluation and Planning System) model, the hydrological (precipitation, flow, evaporation) data of important water resources for the basin and Izmir (Tahtalı, Seferihisar, Ürkmez, and Kavakdere Dams) were used to predict the availability of water resources in the future, and several possible scenarios for water demands/supplies were analyzed. The water budget balances projected in 2050 have been calculated by considering six different scenarios: Reference Scenario, Report Consumption Scenario, Optimistic Case Scenario, Pessimistic Case Scenario, Return Flow Scenario, and Various Forecast Scenario. The water balances that can be obtained in each scenario under various situations were computed and compared. For all considered scenarios, unmet water demand in the basin is found to be significant (157.52 hm3 in the Optimistic Case Scenario and 373.16 hm3 in the Pessimistic Case Scenario).Article Citation - WoS: 7Citation - Scopus: 7Neo-Clerodanes From Teucrium Divaricatum Subsp. Divaricatum and Their Biological Activity Assessment(Elsevier, 2023) Aydoğan, Fadime; Ali, Zülfiqar; Zülfiqar, Fazila; Karaalp, Canan; Khan, Ikhlas A.; Bedir, ErdalFifteen neo-clerodane diterpenoids (1–15), including two undescribed glycosides, teudivaricosides A (1) and B (2), together with a known iridoid glycoside (16) and a phenylpropanoid glycoside (17) from the whole plant of Teucrium divaricatum subsp. divaricatum were isolated. Their structures were determined by spectral data analysis including 1D and 2D NMR and HRESIMS. Neo-clerodane diterpenoids were evaluated for their anti-inflammatory, and antimicrobial activities. None of them showed significant antimicrobial activity against various bacterial and fungal strains (up to 20 µg/mL). All tested compounds were inactive up to the highest tested concentration of 50 µM on iNOS inhibitory activity.Article Citation - WoS: 3Citation - Scopus: 3Determination of Activation Energy for Carbon/Epoxy Prepregs Containing Carbon Nanotubes by Differential Scanning Calorimetry(SAGE Publications, 2022) Uz, Yusuf Can; Tanoğlu, MetinThe aim of the present study is the thermal characterization of laboratory-scale carbon fiber/epoxy-based prepregs by incorporating single-wall carbon nanotubes (SWCNTs). Investigation of the cure behavior of a prepreg system is crucial for the characterization and optimization of the fiber reinforced polymeric (FRP) composite. To affect dispersion characteristics, SWCNTs were functionalized by oxidizing their surface with carboxyl (-COOH) group using an acid treatment. The modified resin system contained 0.05, 0.1, and 0.2 wt. % functionalized SWCNTs (F-SWCNTs). Carbon fiber (CF) reinforced prepregs containing various amount of F-SWCNTs were prepared using drum-type winding technique. FTIR was performed to identify new bonding groups formed after the functionalization of SWCNTs. Cure kinetics of prepregs prepared with/without F-SWCNTs were investigated using isoconversional methods.Article Citation - WoS: 3Citation - Scopus: 3For Whom the Bell Tolls? Towards a Flexible Concept of Authenticity for Religious Heritage Buildings in Political Conflict Zones–case of Northern Cyprus(Taylor & Francis, 2022) Saifi, Yara; Yüceer, Hülya; Hürol, YoncaThis article discusses the possibility of developing an understanding of the concept of authenticity through the understanding of authenticity in architectural terms, specifically religious heritage buildings in areas of political conflict. Although authenticity has been a continuous subject of debate in the field of heritage studies, however, we argue that difficulties in coming to terms with its application in areas of conflict are still persistent. The study uses the case study of the Agios Synesios Church in North Cyprus, built around the Twelfth century, and is still in use by the Greek Cypriot minorities who continued to live on the island following its division in 1974 and the forced displacement of both Turkish and Greek Cypriot communities to either part of the island. Based on observation of the church and its surrounding context, the research shows that coming to terms with authenticity is problematic for the church since the prolongation of the Greek Cypriot way of life has been compromised due to political fluctuations. The argument suggests that once the authenticity of a religious building is assessed as a heritage asset, a flexible concept of authenticity is essential to consider in areas of political conflicts especially when its original context no longer exists.Article Citation - WoS: 1Citation - Scopus: 1Influence of Processing Method of Cocrmo Dental Alloy on the Corrosion Behavior in Artificial Saliva(Wiley, 2022) Pontes, Joana R.; Pinto, Ana M. P.; Ariza, Edith; Alves, Alexandra C.; Toptan, FatihRemovable or fixed dental frameworks are usually made of CoCr alloys. The CoCr dental alloys are produced traditionally by lost-wax casting. However, alternative processing routes, such as hot-pressing, are being studied for dental applications. The purpose of the present work was to assess the corrosion resistance of CoCrMo dental alloy produced by conventional lost-wax casting and hot-pressing. The corrosion behavior was studied in artificial saliva at 37°C by potentiodynamic polarisation tests. Immersion tests were performed to evaluate the growth of the passive film where electrochemical impedance spectroscopy was used at different immersion periods. Results showed slightly better corrosion resistance in terms of ipass for CoCrMo samples obtained by hot-pressing. On the other hand, the immersion tests showed a more stable and thicker passive film formed on hot-pressed CoCrMo dental alloy, pointing out that hot-pressing may be considered a promising technique to produce CoCrMo dental structures.Article Characterization of Yellow Patina on Stone Surfaces by Instrumental Analysis Including Libs(Taylor & Francis, 2022) Badur, Fulya; Aras, Nadir; Yalçın, Şerife; Böke, HasanYellow patina formed on the stone surfaces of historical buildings, monuments, and archaeological structures due to weathering is considered a value of the building in the conservation of cultural heritage studies. Although yellow patina layers can be easily distinguished on white marble surfaces, it is not possible to distinguish them on the yellow travertine surfaces with the naked eye. It should be taken into account in yellow travertines as well as marble surfaces before conservation treatments of the stone. In this study, mineralogical and chemical compositions and the thicknesses of yellow patina layers formed on yellow travertine and marble surfaces in Aizanoi, Aphrodisias, and Hierapolis archaeological sites in Turkey were analyzed in order to constitute a conservation approach in the archaeological sites. In this respect, XRD, FT-IR, SEM-EDX, and LIBS were used in the determination of compositions and thicknesses of yellow patina. Although LIBS analysis is a more convenient method to investigate patina layers on stone surfaces, this technique is not as well known as the others. Yellow patina layers contained calcium oxalate in the form of whewellite (CaC2O4.H2O). Their thicknesses were between 15 and 100 μm and should be protective against weathering on travertine and marble surfaces. Highlights LIBS analysis seems to be the most convenient micro-destructive method to estimate the thickness of the yellow patina layers on the marble and yellow travertine surfaces. The determination of the thickness of the yellow patina is critical to keep irreversible cleaning interventions, especially for the yellow travertines due to their similar colors. Yellow patina is mainly composed of calcium oxalate with clay minerals and organic compounds.Article Citation - WoS: 1Citation - Scopus: 2Preparation and Photocatalytic Performances of Zno Nanostructures: Effects of Anodization Voltage and Time(Wiley, 2022) Öksüz, Ahmet Emrecan; Yurddaşkal, Metin; Doluel, Eyyup Can; Kartal, Uğur; Dikici, TuncayIn this study, ZnO nanostructures with different morphologies were produced by varying anodizing parameters (time and voltage), and the photocatalytic activities of these structures were examined. ZnO nanostructures were fabricated through different voltage and duration consisting of nine samples with KHCO3 solution as an electrolyte. The produced ZnO nanostructures were investigated by using X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy, and UV–vis spectrophotometer. It was found that the morphology of ZnO was formed as nanosponge, nanoflower, nanowire, heterogeneous structures. ZnO nanostructures were identified by matching XRD peaks due to the ICDD database. Experiments on photocatalytic degradation of methylene blue demonstrated the photocatalytic activity of ZnO samples. The best photocatalytic performance of the samples was observed by S1 sample, which was anodized for 30 min in 0.05 M of KHCO3 electrolyte at 20 V, after 420 min exposure of the UV–vis light source with the degradation rate of 87.3%. Such ZnO nanostructures exhibit unique properties and have high potential for wastewater treatment.Article Citation - WoS: 3Citation - Scopus: 3Structural and Functional Analyses of Gh51 Alpha-L of Geobacillus Vulcani Gs90 Reveal Crucial Residues for Catalytic Activity and Thermostability(Wiley, 2022) Sürmeli, Yusuf; Şanlı Mohamed, GülşahAlpha-L-arabinofuranosidase (Abf) is of big interest in various industrial areas. Directed evolution is a powerful strategy to identify significant residues underlying Abf properties. Here, six active variants from GH51 Abf of Geobacillus vulcani GS90 (GvAbf) by directed evolution were overproduced, extracted, and analyzed at biochemical and structural levels. According to the activity and thermostability results, the most-active and the least-active variants were found as GvAbf51 and GvAbf52, respectively. GvAbf63 variant was more active than parent GvAbf by 20% and less active than GvAbf51. Also, the highest thermostability belonged to GvAbf52 with 80% residual activity after 1 h. Comparative sequence and structure analyses revealed that GvAbf51 possessed L307S displacement. Thus, this study suggested that L307 residue may be critical for GvAbf activity. GvAbf63 had H30D, Q90H, and L307S displacements, and H30 was covalently bound to E29 catalytic residue. Thus, H30D may decrease the positive effect of L307S on GvAbf63 activity, preventing E29 action. Besides, GvAbf52 possessed S215N, L307S, H473P, and G476C substitutions and S215 was close to E175 (acid–base residue). S215N may partially disrupt E175 action. Overall effect of all substitutions in GvAbf52 may result in the formation of the C–C bond between C171 and C213 by becoming closer to each other.