Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Icier, Filiz(2)
- Sabanci, Serdal(2)
- Çelik, Ertuğrul(2)
- Barim, Esra(1)
- Cevik, Mutlu(1)
- Coskun, Abdulkadir(1)
- Demirelli, Kadir(1)
- Göksu, Ali(1)
- Güler, Onur(1)
- Gürler, Nedim(1)
- Karabacak, Abdullah Hasan(1)
- Kaya, Kübra(1)
- Ozkaya, Serdar(1)
- Sekban, Dursun Murat(1)
- Torğut, Gülben(1)
- Yanar, Harun(1)
- Yüzüak, Ercüment(1)
- Yüzüak, Gizem Durak(1)
- Çelebi, Müslim(1)
- Çetin, Mehmet(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ1Preparation of Nanographene-Based Copolymer Nanocomposites: Thermal Decomposition Kinetic, Optical, and Electrical Behaviors
Barim, Esra; Demirelli, Kadir
The poly(4-methacryloyloxyphenyl-4'-methoxystyryl ketone-co-methyl methacrylate) [P(MPMESK0.25-co-MMA)] was synthesized using a free radical copolymerization method at 60 °C. The composition of the copolymer was estimated by 1H-NMR. The nanocomposites of P(MPMESK0.25-co-MMA)-loaded 9 and 11 wt% nanographene (NG) were produced using the ultrasonic homogenizer sonicator. The FT-IR, 1H-NMR, GPC, TGA, XRD, and SEM techniques were used to characterize the copolymer and composites. The thermal behavior of P(MPMESK0.25-co-MMA) partially heated up to 270, 310, 340, and 380 °C was investigated by FT-IR analysis. A six-membered anhydride ring in the copolymer backbone formed at 340 °C and higher temperatures. TG measurements were used to analyze the thermal decomposition processes of pure P(MPMESK0.25-co-MMA) and P(MPMESK0.25-co-MMA)/NG 11 wt% composite. Apparent activation energies for thermal decomposition of P(MPMESK0.25-co-MMA)/NG 11 wt% were determined using the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods at a temperature range of 200 and 400 °C for a weight loss of approximately 70%. The average activation energies determined from the FWO and KAS methods were 86.3 and 80.3 kJ/mol, respectively. The dielectric and electrical behaviors of the P(MPMESK0.25-co-MMA) and P(MPMESK0.25-co-MMA)/NG 11 wt% composite were investigated at room temperature. The dc activation energy for dc conductivity of nanocomposite was calculated as 1.092 eV. Optical properties such as absorption, reflectance, refractive index, absorption edge, direct band gap of the copolymer, and composites were investigated from their optical examinations in the wavelength region of 200–800 nm. It was found that the optical energy gap values had shifted to the lower energies with the doping of NG.
AtıfScopus1OpenAlex1
İncele - MakaleYalnız künye2026Scopus SJRQ2Influence of Low-SiC Content on the Tribological and Electrical Properties of Cu Composites Produced by Spark Plasma Sintering
Çelik, Ertuğrul
In this study, copper matrix composites reinforced with varying silicon carbide (SiC) contents (0.25, 0.5, 0.75, and 1 wt.%) were fabricated using spark plasma sintering (SPS). The effects of SiC reinforcement on the microstructure, hardness, porosity, electrical conductivity, and tribological performance were systematically investigated. Brinell hardness values increased with higher SiC content, reaching up to 76 HB for the 1 wt.% SiC composite. This improvement was accompanied by a gradual increase in porosity from 0.6 to 2.1%. Electrical conductivity decreased from 93% IACS to 66% IACS with increasing SiC content. Tribological tests revealed that the specific wear rate was significantly reduced, reaching as low as 1.1 × 10−4 mm3/N m at 15 N due to the formation of a protective tribolayer. These results demonstrate that incorporating small amounts of SiC can substantially improve hardness and wear resistance, while maintaining acceptable electrical performance, making Cu-SiC composites promising candidates for durable electrical contact applications.
AtıfScopus1WoS1OpenAlex1
İncele - 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 SJRQ2Optimizing the thermoelectric performance of Bi-Sb-Te thin films through compositional engineering
Yüzüak, Gizem Durak; Çetin, Mehmet; Yüzüak, Ercüment
The objective of the present investigation was to systematically investigate the structural and thermoelectric (TE) properties of BixSb2-xTe3 thin films with varying content of Bi. We investigated the impact of different atomic percentages of Bi (4, 6, 8 at. %) on the properties of carrier transport and TE performance. In general, the Seebeck coefficient remained consistent across the thin films. For the 8 at. % Bi thin film, the Seebeck coefficient and electrical conductivity were measured at 230 μV/K and 730 S/cm, respectively, at room temperature. These values were more than 20 times greater than the electrical conductivity observed in the thin films with compositions of 6 and 4 at. % Bi. As a result, the Bi-Sb-Te compound exhibited a TE power factor (PF) of 38x10−4 W/mK2 at 40 °C, surpassing the PFs observed in previous compositions. The analysis of surface microstructure, combined with atomic force microscopy and Kelvin probe microscopy images, revealed that the transport of carriers in films with high Bi content was impeded by the size of particles and scattering sites. On the other hand, an augmentation in Bi content promoted the transfer of charge through crystalline regions, hence improving the mobility of carriers and the total electrical conductivity. The aforementioned results emphasize the significant influence of Bi content on the electrical properties of semiconductors and demonstrate the effectiveness of compositional engineering based on Bi content in the development of TE materials with superior performance. The present study investigates the influence of Bi content on the electrical properties of Bi-Sb-Te thin films, demonstrating that compositional adjustments based on Bi content can impact the performance of TE materials. These findings contribute to the understanding of material optimization in the field of TE.
AtıfScopus4WoS5OpenAlex5İncele - MakaleAçık Erişim2023Scopus SJRQ2Modeling the electrical conductivity value of the model solution
Sabanci, Serdal; Kaya, Kübra; Göksu, Ali
The ohmic heating process is one of the novel electrical heating methods that are considered as fast, homogeneous and efficient heating. In this study, the details of the relationship between electrical conductivity (EC)-Temperature (Temp) and EC-pH-Temp at different Total Soluble Solid Content (TSSC) and different pH values were examined. Especially, the study explains details of the electrical conductivity value due to pH change (2, 2.5, 3, 3.5) and expressing EC change depending on the pH value of fruit and vegetable juices. At constant pH, EC values decrease with increasing TSSC values (10%, 20%, 30%, 40%, 50%, 60%) and decrease with increasing pH at constant TSSC value. When the relationship between Temp-EC is analyzed that the EC value increases as Temp increases in all cases and this increase is linear. It was found that the Temp-EC relationship was in high compatibility with an R2 value above 0.97. Also, in the Temp-EC-pH relationship, the R2 value was found to be an acceptable value above 0.95.
AtıfScopus4WoS3
İncele - 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 SJRQ1Numerical simulation of temperature histories of frozen minced meat having different fat contents during ohmic thawing
Cevik, Mutlu; Icier, Filiz
The ohmic thawing (OT) of minced meat sample was mathematically modelled using different numerical methods (Finite Difference-FD and Finite Volume-FV) for different process conditions (voltage gradients of 10, 13 and 16 V/cm and fat contents of meat sample as 2%, 10% and 18%). FD method was successful to predict the temperature changes for both heating and phase change regions. FV method was performed by using two different heat generation functions; depending on process time (UDF-1) or the center temperature (UDF-2). The description of the change of heat generation term depending on process time (UDF-1) in the ANSYS module was more successful with the experimental data compared to the description of the change of heat generation term depending the center temperature (UDF-2). Although FV model is more complex than FD model it can be applied for simulation of detailed temperature distributions. On the other hand, FD model can be applied for practical predictions of temperature histories for center temperatures in simple geometries. It is thought that the simulation of OT performed at different conditions with the FD and the FV methods would contribute valuable data in the design of household ohmic thawing/cooking systems for solid food materials.
AtıfScopus25WoS21OpenAlex21İncele - MakaleYalnız künye2017Scopus SJRQ1Applicability of ohmic heating assisted vacuum evaporation for concentration of sour cherry juice
Sabanci, Serdal; Icier, Filiz
Sour cherry juice having total soluble solids (TSS) of 19.2% was evaporated up to 65% TSS at vacuum (gauge pressure of 580 mm-Hg) by applying ohmic heating at three different voltage gradients (10–14 V/cm). Total process times were determined as 40, 55, 75, and 85 min for 14 V/cm, 12 V/cm, and 10 V/cm, and vacuum evaporation (VE), respectively. The change of moisture content during ohmic assisted vacuum evaporation and VE processes were investigated by seven different empirical models. The best fitting model was Midilli model for three different voltage gradients and VE. The electrical conductivity values at different voltage gradients varied between 0.41 and 1.13 S/m for different TSS contents. The changes of EC values were examined in detail for three different regions; heating up period, first evaporation period, and second evaporation period. EC increased until a critical % TSS content (32% TSS), then remained constant for certain time (until 45% TSS) depending on voltage gradient, and then it had tendency to decrease. Ohmic heat generation increased sharply during heating period, then decreased dramatically during evaporation periods. It is recommended that ohmic heating could be alternatively used as the heat source to shorten the process times of vacuum evaporation applied for concentration of fruit juices.
AtıfScopus91WoS77OpenAlex93İncele