Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Koçak, Berna(2)
- Torğut, Gülben(2)
- ALMisned, Ghada(1)
- Akkurt, Nevzat(1)
- Aksakal, B.(1)
- Aslan, N.(1)
- Aslan, Naim(1)
- Başgöz, Öyküm(1)
- Buran, Dincer(1)
- Canbay, Canan A.(1)
- Canpolat, Erdal(1)
- Coskun, Abdulkadir(1)
- Er, Engin(1)
- Fidan, Ferzan(1)
- Güler, Onur(1)
- Güler, Seval Hale(1)
- Güler, Ömer(1)
- Gürler, Nedim(1)
- Issa, Shams A.M.(1)
- Kahraman, Gökhan(1)
- Karabacak, Abdullah Hasan(1)
- Kaya, Ozge(1)
- Koç, Mümin Mehmet(1)
- Ozkaya, Serdar(1)
- Pihtili, Güzin(1)
- Sarac, Mehmet Fahri(1)
- Sekban, Dursun Murat(1)
- Taşgın, Yahya(1)
- Tekin, H.O.(1)
- Yanar, Harun(1)
- Yapici, Kerim(1)
- Zakaly, Hesham M.H.(1)
- Çelebi, Müslim(1)
- Çelik, Ertuğrul(1)
- Çelikkan, Huseyin(1)
- İpek, Yeliz(1)
- Şahal, Hakan(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Tribological Performance of SPS-Fabricated Cu-HEA/Gr Composites Under Current-Carrying Sliding Contact
Ozkaya, Serdar; Çelebi, Müslim; Yanar, Harun; Karabacak, Abdullah Hasan; Çelik, Ertuğrul; Güler, Onur; Coskun, Abdulkadir; Sekban, Dursun Murat
Cu-based hybrid composites reinforced with AlCrFeCuNi high-entropy alloy (HEA) particles and graphene were successfully fabricated by spark plasma sintering (SPS) to investigate the combined effects of microstructure, mechanical properties, and tribological performance under electrical current. Microstructural observations revealed a dense and homogeneous distribution of HEA particles within the Cu matrix, while the addition of 2.0 wt.% graphene promoted noticeable grain refinement due to its grain boundary pinning effect. Although graphene addition provided beneficial effects in terms of grain refinement and electrical conductivity, it also increased the porosity from 2.49% to 5.08%. Consequently, the beneficial contribution of graphene to mechanical strengthening was substantially offset by the adverse effect of increased porosity, resulting in only a marginal increase in hardness from 127 HB to 129 HB. The addition of 2.0 wt.% graphene led to a pronounced change in the tribological behavior of the composites. The Cu–HEA exhibited relatively stable friction behavior but experienced a higher wear rate under all test conditions. In comparison, the Cu–HEA–2.0 Gr composite demonstrated a lower coefficient of friction and wear rate at 0–10 A, which is consistent with the possible formation of a graphene-rich lubricating surface layer. A clear transition occurred at 30 A, where the coefficient of friction and wear rate began to increase, while at 50 A, further increases in both parameters were observed, suggesting progressive disruption of the proposed protective surface layer under the investigated current-carrying sliding conditions.
- MakaleYalnız künye2024Scopus SJRQ2Evaluating the metallographic properties and performance of heat transfer by natural convection of graphene-coated glass used for heating
Kahraman, Gökhan; Taşgın, Yahya
In this study, a decorative electric heater was manufactured to reduce carbon emissions related to residential and office heating, and this heater was metallographically evaluated. In addition, the heating performance of the manufactured plate was investigated by examining its heat transfer capacity by natural convection. For this purpose, the surface of the tempered glass plate was coated with graphene by spraying to improve its electrical and heat conduction properties. Copper strips were attached to both sides of the plate to allow for an electric current. The plate was connected to mains electricity, and its change in surface temperature over time was measured. Using the measured temperature values, the heat transfer rate by natural convection on the plate surface was calculated. As a result of the calculations, it was determined that the graphene-coated tempered glass plate reached a heating performance of 40 watts after 2400 s of electrical energy supply. This value can be increased by increasing the heat transfer surface area. This study, taking advantage of the excellent thermophysical properties of graphene, will contribute to other studies conducted in this field.
AtıfScopus2WoS2OpenAlex2
İncele - MakaleYalnız künye2023Scopus SJRQ3Nafion–Titanium (IV) Oxide-Graphene Modified Glassy Carbon Electrode (GCE) Based Electrochemical Sensor for the Voltammetric Determination of the β-blocker Bisoprolol Fumarate
Koçak, Berna; İpek, Yeliz
A Nafion–titanium (IV) oxide-graphene modified glassy carbon electrode (n-TiO2-GR/GCE) was used for the electrochemical determination of bisoprolol fumarate (BF). The modified electrode was prepared by depositing Nafion–titanium (IV) oxide-graphene onto the glassy carbon electrode by simple drop-casting. Differential pulse voltammetry (DPV) and square wave voltammetry (SWV) were used in the electrochemical determination of bisoprolol fumarate. The linear working range of bisoprolol fumarate for n-TiO2-GR/GCE DPV was from 3.0 × 10−7 to 5.0 × 10−6mol L−1 and the detection limit was 1.01 × 10−7mol L−1. In addition, with this developed method, the determination of bisoprolol fumarate in tablets was successfully performed with a recovery of 98.65%.
AtıfScopus3WoS2OpenAlex3İncele - MakaleAçık Erişim2023Scopus SJRQ3Morpho-structural and compressive mechanical properties of graphene oxide reinforced hydroxyapatite scaffolds for bone tissue applications
Fidan, Ferzan; Aslan, Naim; Koç, Mümin Mehmet
Hydroxyapatite (HA) is a unique material that has the potential to be used to replace bones and teeth in the field of orthopedics and dentistry since HA exhibits quite similar biological and chemical characteristics to human bone. Hydroxyapatite ceramics are bioactive materials used to repair damaged human tissue. The pores in the porous hydroxyapatite ceramics provide a mechanical interlock, enabling a solid bond and fixation between the implant and bone. In this study, 0.5wt%, 1wt%, and 1.5wt% graphene oxide (GO) reinforced porous HA structures were obtained using the space-holder method to increase the strength of hydroxyapatite with low mechanical strength. NaCl was used as a spacer, and PEG 400 as a binder. Scaffold structures with 40% porosity rates were sintered at 1000 °C under vacuum. Finally, a compression test was applied to the samples which were previously analyzed by SEM, EDS and XRD. The compressive strengths of 0.5%, 1%, and 1.5% graphene oxide reinforced porous HA samples were determined between 8.04 and 31.14 MPa. The highest compressive strength was recorded as 31.14 MPa in the 1% GO added sample, and the lowest compressive strength was recorded as 8.04 MPa in the 1.5% GO added sample. In addition, it was understood that the mechanical properties did not increase regularly with the increase of graphene oxide reinforcing.
AtıfScopus4OpenAlex3
İncele - MakaleAçık Erişim2022Scopus SJRQ2Optimization of Electrical Conductivity of SA-graphene Nanocomposites Using Response Surface Methodology
Şahal, Hakan; Torğut, Gülben; Canpolat, Erdal
Synthesis and characterization of 4-{(E)-[(5-bromo-2-hydroxyphenyl)methylidene]amino}-N-carbamimidoylbenzene-1-sulfonamide(SA) and its composites with graphene(SA-GF) were performed. Compound SA and SA-GF were characterized by FTIR and 1H NMR. The GF dispersion in the composites was analyzed by means of scanning electron microscopy(SEM) for morphology. Thermal properties of SA and nanocomposites were investigated using differential thermal analysis(DTA) and thermogravimetric analysis(TGA). The optimum electrical conductivity of the new sulfonamide-based Schiff base was determined to be 1.78×10−5 S/cm at a frequency of 9923 Hz, an applied voltage of −19 V, a mass fraction of 9.38% for graphene loading using a central composite design in the response surface methodology. The significance of the selected parameters(frequency, voltage and GF amount) in the model was determined by the analysis of variance(ANOVA). The results showed that frequency and graphene loading represent important model terms and have considerable effects on the conductivity of SA.
AtıfScopus3WoS3OpenAlex2İncele - MakaleAçık Erişim2022Scopus SJRQ2Synergistic effect of boron nitride and graphene nanosheets on behavioural attitudes of polyester matrix: Synthesis, experimental and Monte Carlo simulation studies
Başgöz, Öyküm; Güler, Seval Hale; Güler, Ömer; Canbay, Canan A.; Zakaly, Hesham M.H.; Issa, Shams A.M.; ALMisned, Ghada; Tekin, H.O.
We report the synergistic effects of boron nitride and graphene nanosheets on physical, structural, and nuclear radiation attenuation properties of polyester matrix-incorporated nanocomposites. Some critical material properties are thoroughly evaluated for several types of synthesized samples. Polyester is employed to strengthen graphene and boron nitride nanolayers, and their characteristics are investigated in detail. Additionally, we report the gamma-ray and fast neutron attenuation characteristics of synthesized nanocomposites to get a better understanding of the reinforcing effect as a function of material type and weight percentage. Thermal analysis findings indicate that adding graphene lowers the decomposition temperature but co-adding graphene and BNNS enhances thermal decomposition in comparison to graphene itself. Tensile tests showed that the inclusion of both GRP and GRP/BNNS strengthens the material. Among the polyester composite samples analyzed, the G3 sample with the most GNP reinforcement had the lowest HVL values throughout the broadest range of energy levels investigated. The recent findings may be beneficial to the scientific community in terms of incorporating these reinforcing types and ratios into polyester materials for a variety of applications, including industrial and research purposes.
AtıfScopus22OpenAlex19İncele - MakaleYalnız künye2022Scopus SJRQ1Graphene-reinforced novel poly(acetoxystyrene-co-glycidylmethacrylate) composites: Synthesis and optimization of dielectric behaviors using response surface methodology
Pihtili, Güzin
In this work, a new copolymer synthesis of Poly(acetoxystyrene-co-glycidylmethacrylate) (P[AOS-co-GMA]) by free radical polymerization (FRP) method is reported. The polymer composites (P[AOS-co-GMA]/graphene), containing different amounts of graphene, were prepared by the solution casting technique. Composites of Poly(acetoxystyrene-co-glycidylmethacrylate) loaded with 2.03 mass%, 5.00 mass%, 7.97 mass%, and 10 mass% graphene. The structure of AOS-GMA systems was characterized by fourier transform infrared, 1H-NMR and scanning electron microscopy. Thermal features were evaluated by the thermogravimetric analysis and differential scanning calorimetry. The aim of this study is to optimize the ε′ (dielectric constant) and ε′′ (dielectric loss factor) of pure polymer and graphene-doped (2.03-5-7.97-10 mass%) P(AOS-co-GMA) composite using response surface methodology. For optimization of the process and creation of the mathematical model, the central composite design package was used. The significance of the process parameters in the model was evaluated by analysis of variance (ANOVA) research. The effects of process parameters, frequency (Hz), voltage (V), and graphene ratio (mass%) on ε′ and ε′′ were examined at ambient temperature. The maximum ε″ value (8.01) was reached at around the 699 Hz frequency and at 11.43 V voltage at the graphene content of 9.82 mass%. The model estimated the maximum value of the ε′′ (0.08) when the frequency was set at 51.20, the voltage was fixed at 1.16 and the graphene content was fixed at 9.97 wt%. The ANOVA results showed that frequency and graphene content were the main model parameters and had a remarkable effect on the dielectric properties. This article presents the development of a new polymeric composite and optimize effect of process parameters, such as frequency (A), voltage (B) and amount of graphene (C).
AtıfScopus4WoS4OpenAlex4İncele - MakaleYalnız künye2021Scopus SJRQ2Graphene-reinforced potato starch composite films: Improvement of mechanical, barrier and electrical properties
Gürler, Nedim; Torğut, Gülben
In this study, PSG composite films were prepared by casting method by adding graphene (G) to glycerol plasticized potato starch (PS) films. The structure and properties of the composite films were investigated attenuated total reflectance Fourier transform infrared (ATR-FTIR), X-ray analysis (XRD), and swelling capacity, total soluble matter, transparency, tensile strength, and electrical conductivity. When the G content of PSG composite films increased from 0% to 1%, tensile strength increased from 1.035 MPa to 1.681 MPa, but decreased to 1.175 MPa in composite films containing 2% G. It also increased electrical conductivity when the G concentration increased. Also, the G layers are among the PS films and their swelling and solubility properties are reduced. With increased G concentration, the light transmittance decreased and the films were more opaque. These improvements can refer to the interface interaction between PS and G.
AtıfScopus43WoS35OpenAlex39İncele - MakaleYalnız künye2021Scopus SJRQ2Effect of graphene reinforcement on hybrid bioceramic coating deposited on the produced porous Ti64 alloys
Aslan, N.; Aksakal, B.
Porous-Ti64 alloys (P-Ti64), produced at various porosities by hot-pressing technique with the help of Mg spacer, were coated by hybrid-Graphene Oxide (rGO) reinforced-hydroxyapatite (HAp), using the sol–gel method. The synthesized rGO powder was used in reinforcing HAp by the Modified Hummers method having 30 µm particle size and nano (nm) scale layer thickness. Hybrid coatings were executed on Ti64 substrates in four different groups as single-HAp, HAp reinforced with 0.5 wt%, 1.0 wt% and 1.5 wt% rGO for three different porosities (41, 52, and 64%) were characterized by FT-IR, Raman, XRD and SEM. The average 21 µm coating film thicknesses were obtained and desirably, the only superficial pores of the substrates were closed by coating material rather than the inner connected open pores. It was also shown that 0.5 wt% and 1.0 wt% rGO reinforcements into HAp prevented crack formation on the Ti64 surfaces, whereas 1.5 wt% rGo reinforcement and single-HAp coatings caused. The highest adhesion strength values were achieved at low porosities (41–52%) and of 0.5–1.0 wt% rGO reinforcements through the adhesion tests.
AtıfScopus14WoS12OpenAlex20İncele - MakaleYalnız künye2021Scopus SJRQ2Characterization of Various Carbon-Based Polypropylene Nanocomposites
Kaya, Ozge; Buran, Dincer; Akkurt, Nevzat; Yapici, Kerim; Sarac, Mehmet Fahri
Pure and three types of carbon additives including graphite, graphene, and multi-walled carbon nanotube added into polypropylene (PP) composites as a vibration damping component and sound insulator material in the automotive sector were investigated by using vibrational damping, dynamic mechanical analysis (DMA), tensile, hardness and acoustic behavior tests. According to the obtained results, porosity and distribution of carbon in the polymer matrix are key parameters on the composite parameters causing its reduction of tensile strength and its brittle behavior. Moreover, it seems that 0.01 wt.% graphene and 1 wt.% graphite added PP composites show the highest impact damping properties and also increase the storage and loss modulus of the composite while decreasing the glass transition temperature. The loss factor obtained from DMA and vibration damping test indicated the damping capacity in the interphase of carbon added PP composites depends only on the load applied and not sensitivity upon the natural frequency of the composite system. Depending on the morphological differentiation, graphene added PP composites decrease the sound transmission loss while the 0.1 wt.% MWCNT added PP composites increase sound transmission loss which makes it an alternative vibration damping component.
AtıfScopus6WoS6İncele - MakaleYalnız künye2015Scopus SJRQ1Stripping voltammetric analysis of dicofol on graphene-modified glassy carbon electrode
Koçak, Berna; Er, Engin; Çelikkan, Huseyin
This study is related to the development of a highly sensitive and selective electrode for the electroanalysis of dicofol (DCF) by the modification of a glassy carbon electrode (GCE) with graphene (GR) nanosheets. GR was characterized by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), transmission electron microscopy (TEM), and electrochemical methods. The electrochemical reduction of DCF was observed on both bare GCE and GR-modified GCE (GRE). The electrochemical reaction of DCF on GRE was observed to be an adsorption controlled. Differential pulse stripping voltammetry was chosen in the electrochemical analysis of DCF, and two linear calibration ranges from 5.0 x 10(-8) to 5.0 x 10(-7) M and from 5.0 x 10(-7) to 4.2 x 10(-4) M were obtained with a low detection limit of 1.08 x 10(-7) M (N = 5) under the optimized experimental conditions. The electrode developed was successfully used to monitor dicofol in a series of spiked samples.
AtıfWoS6OpenAlex9İncele
