Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Kök, Mediha(2)
- Ak, Tuba Parlak(1)
- Aksu Canbay, Canan(1)
- Arman, Yusuf(1)
- Aydin, Handan(1)
- Aydın, Cihat(1)
- Aydın, Handan(1)
- Baykalir, Burcu Gul(1)
- Coşkun, Meltem(1)
- Deniz Çirak, Zehra(1)
- Dogan, Akar(1)
- Dogan, Sonay(1)
- Doğan, Akar(1)
- Güler, Seval Hale(1)
- Güneş, Çağdaş(1)
- Icier, Filiz(1)
- Ilhan, Nevin(1)
- Kanca, M. Sait(1)
- Karaduman, Oktay(1)
- Sabancı, Serdal(1)
- Susam, Solmaz(1)
- Tatar, Cengiz(1)
- Yalçln, Beyza Furtana(1)
- Yllmaz, Mehmet(1)
- Özdemir, Ahmet Münir(1)
- Özen Öner, Ecem(1)
- Özkul, İskender(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ3Functional magnetic polymer nanocomposites: Fe2O3/Fe3O4-enhanced PCL-PVA materials
Deniz Çirak, Zehra; Aydin, Handan; Coşkun, Meltem; Kök, Mediha
In this study, magnetic polymer nanocomposites based on PCL/PVA PCL(Polycaprolactone)-PVA(Polyvinyl alcohol) (80/20) reinforced with Fe2O3 and Fe3O4 nanoparticles were successfully produced, and their thermal, structural, morphological, and magnetic properties were comparatively investigated. The systematic evaluation of the effects of Fe2O3 and Fe3O4 additions on the same biodegradable polymer matrix at 20% and 40% loading levels constitutes the main novelty of this study. The nanocomposites were characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and physical property measurement system (PPMS) analyses. The TGA results demonstrated that the decomposition onset temperature increased with the addition of nanoparticles and, particularly in the composite with 40% Fe3O4 content, the residual mass reached 15.81%, indicating a significant improvement in thermal stability. DSC analyses showed that the melting peak temperature increased at high loading levels and that Fe2O3 loading supported crystallization more than Fe3O4. FTIR and XRD results confirmed that the nanoparticles dispersed successfully in the polymer matrix without forming chemical bonds and provided strong interfacial interactions. The SEM images revealed a homogeneous distribution at low loading levels, while significant agglomeration formed at high Fe3O4 content. Magnetic measurements indicated that the pure PCL/PVA blend exhibited diamagnetic behavior, Fe2O3-containing composites displayed hard ferromagnetic behavior, and Fe3O4-containing composites exhibited soft ferromagnetic behavior. The highest saturation magnetization of 10.4 emu/g was obtained in the composite with 40% Fe3O4 content. The findings indicate that Fe2O3- and Fe3O4-doped PCL/PVA nanocomposites are functional materials with high potential for applications in sensors, actuators, magnetically controlled systems, and biomedical applications.
- MakaleAçık Erişim2026Scopus SJRQ1Change in phase stability and transformation kinetics of NiTiCuW alloy after heat treatment at 650–850 °C
Tatar, Cengiz; Kök, Mediha; Kanca, M. Sait
In this study, the effects of different heat treatment temperatures (650 °C, 750 °C, and 850 °C) on the phase transformation behavior, microstructure, thermodynamic parameters, and microhardness of the NiTiCuW alloy, produced by adding tungsten (W) to the NiTiCu shape memory alloy, were investigated. The crystal structure change was determined by X-ray diffraction (XRD), the transformation temperatures were determined by differential scanning calorimetry (DSC), the microstructure was examined by scanning electron microscopy (SEM), and the mechanical properties were evaluated by Vickers microhardness measurements. XRD results showed that the reference and 850 °C samples were predominantly in the B2 (austenite) phase at room temperature, while martensitic phases (B19/B19′) became prominent at 650 °C and 750 °C. DSC analyses revealed that the transformation peaks became sharper at 650 °C and the R-phase transformation could be observed; at 750 °C, the peaks broadened, indicating a decrease in transformation stability. The austenite finish temperature (Af) increased from 2.1 °C (reference) to 52.9 °C at 650 °C and 60.3 °C at 750 °C, while it remained low (4.5 °C) at 850 °C. Thermodynamic evaluations showed that ΔS increased at 650 °C (0.053 J/g K) and decreased at 750–850 °C (≈0.032 J/g K). Microhardness reached its maximum value at 650 °C (398 Hv), decreased at 750 °C (271 Hv), and showed an upward trend again at 850 °C (351 Hv), compared to the reference value (243 Hv). These results indicate that the heat treatment temperature critically determines the functional and mechanical performance of the NiTiCuW alloy.
- MakaleAçık Erişim2025Scopus SJRQ3Effect of polymer modification on bitumen rheology: A comparative study of bitumens obtained from different sources
Özdemir, Ahmet Münir; Yalçln, Beyza Furtana; Yllmaz, Mehmet
The rheological and mechanical properties of bituminous binders vary significantly depending on the crude oil source. Consequently, the response of binders from different sources to polymer modification also differs. This study compares the rheological performance of B160/220 penetration-grade binders sourced from the Turkey-Batman and Iraq-Lanaz refineries, modified with styrene-butadiene-styrene (SBS), the most widely used polymer additive. To evaluate high-temperature performance, performance grade and frequency sweep tests were conducted using a dynamic shear rheometer. In addition to experimental assessments, the rheological behavior of the binders was analyzed using the Christensen-Anderson, Cross, and Carreau-Yasuda models. Time-temperature superposition principle master curves were generated to characterize their viscoelastic behavior. Zero shear viscosity (ZSV) values were determined using the Cross and Carreau-Yasuda models to examine the impact of polymer modification on binder viscosity. The findings indicate that the initial rheological properties of bitumen significantly influence its response to SBS modification. For instance, the G∗/sin δvalue increased by up to 199% at 64°C with 4% SBS addition, while the softening point rose by 9.5°C compared to unmodified binders. Modelled ZSV values showed more than a sevenfold increase in some cases, especially in Iraqi binders. On the other hand, at -18°C, the m-value dropped to 0.282 in the B-SBS4 binder, indicating a potential risk of low-temperature cracking. While polymer modification improved the rheological properties of both bitumen types, its effectiveness varied depending on the source.
AtıfScopus8WoS8OpenAlex7
İncele - MakaleAçık Erişim2025Scopus SJRQ3Role of tungsten oxide (WO3) on thermal and optical properties of smart polymer composites
Aydın, Handan; Özen Öner, Ecem; Aydın, Cihat
Tungsten oxide, a versatile transition metal with numerous polymorphs and sub-stoichiometric compositions, containing inherent tunnels and oxygen vacancies, has become a current field of study due to its rich crystal structure, high electrochemical stability, easy accessibility, and environmental friendliness. Thus, the versatile structure of WO3-based materials makes them promising candidates for advanced applications. Our study aims to provide valuable insights into the performance of these materials used in various fields. The structural, optical, and thermal characteristics of PVC-PCL composites doped with tungsten oxide (WO3) were examined in this work. According to DSC research, the thermal characteristics of the polymer matrix were significantly impacted by the addition of WO3. The thermal stability was found to have increased based on the TGA measurement findings. XRD analyses revealed that as the doping rate increased, improved crystallinity was seen. According to SEM tests, the grain clusters are uniformly mixed and the tungsten oxide is evenly spread across the surface. The dopant reacted either chemically or physically with the polymer matrix, according to the ATR-FTIR spectra of PVC-PCL matrix nanocomposite films. An improvement in conductivity with an increase in dopant concentration was noted in the optical experiments. Thus, it can be stated that PVC-PCL composites doped with WO3 can be used in optoelectronic, various industrial, and biomedical application areas due to their structural, optical, and thermal properties.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2024Scopus SJRQ2Mechanical and thermal properties of short banana fiber reinforced polyoxymethylene composite materials dependent on alkali treatment
Doğan, Akar; Güneş, Çağdaş
The present study aimed to develop a recyclable composite material based on a natural product, namely banana fiber, instead of synthetic reinforcement elements such as glass fiber or carbon fiber in thermoplastic matrix composites employed in many aspects of daily life. Polyoxymethylene (POM) thermoplastic was used as the matrix material. 3 %, 6 %, and 9 % by weight short natural banana fiber was used as reinforcement. Furthermore, the study improved the mechanical and thermal properties of the composite material with chemical improvements based on alkali treatment of banana fiber. Banana fiber and POM was initially mixed mechanically and then extruded at temperatures between 170 and 190 °C to obtain a homogeneous mixture. The mixture obtained by extrusion was initially cooled in the cooling pool and then passed through the crusher to obtain granules. These granules were pressed in plastic injection molds to obtain standard test samples. The ratio of reinforcement material and the variations in mechanical and thermal properties of the composites induced by the alkali treatment are presented in figures and tables. Furthermore, the changes in cross-sectional material images were examined with electron microscopy scans. The tensile and flexural strength of the material improved with alkali treatment.
AtıfScopus21WoS19OpenAlex20İncele - MakaleAçık Erişim2024Scopus SJRQ2High thermal stability effect of vanadium on the binary CuAl base alloy for a novel CuAlV high-temperature shape memory alloy
Karaduman, Oktay; Özkul, İskender; Güler, Seval Hale; Aksu Canbay, Canan
In this study, two high-temperature shape memory alloys (HTSMAs) of CuAlV with unprecedented chemical compositions were fabricated using the arc melting technique, followed by traditional ice-brine water quenching after the melting process. To characterize the shape memory properties and structure of the alloys, a series of tests including differential calorimetry (DSC and DTA), EDS, optical microscopy, and XRD were conducted. The DSC tests, performed at different heating and cooling rates, demonstrated highly stable reversible martensitic phase transformation peaks at high temperatures, which were also confirmed by the results of DTA tests. Microstructural XRD and optical microscopy tests were conducted at room temperature, revealing the martensitic structure of the alloys in both cases. Based on all the results, the effects of different minor amounts of vanadium additives directly on the CuAlV alloy were discussed.
AtıfScopus2WoS2OpenAlex3İncele - MakaleYalnız künye2023Scopus SJRQ2Effect of impactor nose form on the impact behavior of reinforced composite materials
Dogan, Sonay; Arman, Yusuf; Dogan, Akar
The goal of the present study is to investigate the influence of impactor shape on the low-velocity impact behavior of the composite panels manufactured with different reinforcement materials at the same thicknesses, experimentally. Kevlar, carbon, S-2 glass woven fabric and epoxy matrix have been used to manufacture thermoset composites with the vacuum-assisted resin infusion molding method. The Fractovis plus test machine with a 12.7 mm diameter hemispherical and two different conical impactor noses was used to perform impact tests. The effects of impactor shapes on the low-velocity impact behavior have been compared for 20 J, 40 J, and 60 J energy levels. Although at the same impact energy level, S-2 glass fiber-reinforced epoxy specimens have a higher perforation threshold than carbon and Kevlar fiber-reinforced epoxy. Because to achieve the same thickness, the number of S-2 glass layers was greater than the number of carbon and Kevlar layers. Additionally, the form of the impactor greatly influenced the perforation threshold.
AtıfScopus7WoS7OpenAlex6İncele - MakaleYalnız künye2019Scopus SJRQ2Effects of Vacuum Ohmic Evaporation on Some Quality Properties of Sour Cherry Juice Concentrates
Sabancı, Serdal; Icier, Filiz
Sour cherry juice (SJ) having total soluble solid (TSS) content of 19.2 % was concentrated to 65 % TSS by applying vacuum ohmic evaporation (VOE) and vacuum evaporation (VE) methods under constant absolute pressure (25 kPa). Total monomeric anthocyanin content (TMAC) of sour cherry concentrate (65 % TSS) was found in the range of 1561.67–1777.38 mg/L whereas total phenolic content (TPC) varied in the range of 9,071.22–78,347.53 mg/L concentrate. TPC and TMAC values of juice concentrates were affected less from VOE process compared to VE (p < 0.05) while there was no significant difference between the total antioxidant activities of SJ concentrates obtained by both methods (p > 0.05). TMAC and TPC values increased as the voltage gradient applied increased (p < 0.05). VOE process preserved the color properties of juice concentrates better compared to the VE process. It was concluded that VOE method could be an alternative fast evaporation method to obtain high-quality fruit juice concentrates.
AtıfScopus35WoS31OpenAlex34İncele - MakaleAçık Erişim2018The antiiflammatory effect of Ginkgo biloba in lipopolysaccharide-induced rat sepsis model
Ilhan, Nevin; Susam, Solmaz; Ak, Tuba Parlak; Baykalir, Burcu Gul
Background: Sepsis is characterized dysregulated inflammatory response and is the leading cause of organ failure or injury and death in critical care units. Ginkgo biloba extract 761 (EGb 761) is characterized by antioxidant activity. There is no clear data in the functional role of EGb 761 that inhibiting of proinflammatory cytokines exist in sepsis. The purpose of this study was to investigate the antiinflammatory effect of EGb 761 on the levels of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9) and inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS) induced rat sepsis model. Methods: The animals were randomly divided into the following six groups: the control, LPS, flunixin meglumine (FM), EGb 761, LPS + FM and LPS + EGb 761 groups. Enzyme-linked immunosorbent assay (ELISA) analysis was applied to measure serum levels of VEGF, MMP-9, and iNOS. Results: Serum iNOs (p < 0.05), VEGF (p < 0.01) and MMP-9 (p < 0.05) levels were significantly higher in the sepsis group. Treatment with EGb 761 decreased serum iNOs levels (p < 0.01), VEGF and MMP-9 levels decreased significantly (p < 0.05). Also, treatment with FM decreased iNOs (p < 0.01), VEGF and MMP-9 levels significantly (p < 0.05). Conclusions: It is suggested that sepsis may lead to increase serum iNOs, MMP-9, and VEGF levels and treatment of EGb 761 may have a potential antiinflammatory effect against LPS-induced sepsis.
AtıfOpenAlex1İncele - DergiInternational Journal of Food Engineering
- DergiJournal of Laboratory Medicine
- DergiApplied Rheology
- DergiMaterialpruefung/Materials Testing
- DergiOpen Physics
- DergiReviews on Advanced Materials Science