Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Güler, Ömer(8)
- Özkul, İskender(7)
- Aslan, Naim(6)
- Aksakal, B.(5)
- Artuğer, Fırat(5)
- Aslan, N.(5)
- Kahraman, Gökhan(5)
- Say, Yakup(5)
- Tekin, H.O.(5)
- Canbay, Canan Aksu(4)
- Danabas, Durali(4)
- Dikici, B.(4)
- Gul, Muhammet(4)
- Ince, Muharrem(4)
- Kaplan Ince, Olcay(4)
- Karaduman, Oktay(4)
- Koç, Mümin Mehmet(4)
- Kutlu, Banu(4)
- Taşgın, Yahya(4)
- ALMisned, Ghada(3)
- Ates, Mehmet(3)
- Aşkin, A.(3)
- Baykal, Duygu Sen(3)
- Cihangir, Salih(3)
- Doğan, Fatih(3)
- Güler, Seval Hale(3)
- Imak, Andaç(3)
- Karaaslan Ayhan, Nagihan(3)
- Kök, Mediha(3)
- Topal, Murat(3)
- Torğut, Gülben(3)
- Yucesan, Melih(3)
- Özkaynak, Fatih(3)
- Akkurt, Nevzat(2)
- Aksoy, M.E.(2)
- Aksu, Onder(2)
- Alkarrani, Hessa(2)
- Alp Dal, Nursel(2)
- Arslan Topal, E. Işıl(2)
- Arslan, Zikri(2)
Yayınlar
- MakaleAçık Erişim2024Scopus SJRQ2Genotypic diversity and antagonistic activities of enterococci isolated from pastırma
Ertekin, Özlem; Kaban, Güzin; Kaya, Mükerrem
The biodiversity of enterococci from pastırma (a traditional Turkish dry-cured meat product) by genotypic identification and the antagonistic activities of strains were investigated. Pastırma samples taken from 20 different small-scale factories were subjected to microbiological and physicochemical analysis. A hundred enterococci isolates were identified by 16S rRNA gene sequence analysis. To determine antagonistic activity of strains, Listeria monocytogenes and Staphylococcus aureus were used. The lactic acid bacteria and Micrococcus/Staphylococcus counts were ≥ 6 log cfu/g in 55% of the samples and 75% of the samples, respectively. Enterobacteriaceae was generally below the detectable level (< 2 log cfu/g). The enterococci count was higher than 6 log cfu/g in 30–35% of the samples, depending on the medium used. The enterococci isolates (100 isolates) were identified as E. faecium (80 strains), E. faecalis (19 strains) and E. hirae (1 strain) in genotypic identification. The nine E. faecium strains showed antagonistic activity against L. monocytogenes in the well diffusion test. In contrast, in the same antagonistic activity test, all of the strains had no antagonistic activity against S. aureus. Further studies could be planned to characterize E. faecium strains that show antagonistic activity against L. monocytogenes.
AtıfScopus2WoS2OpenAlex1
İncele - MakaleAçık Erişim2024Scopus SJRQ1A new hybrid mobile CNN approach for crosswalk recognition in autonomous vehicles
Doğan, Gürkan; Ergen, Burhan
While automobile transportation is increasing worldwide, it also negatively affects the safety of road users. Along with the neglect of traffic rules, pedestrians account for 22% of all highway traffic deaths. Millions of pedestrians suffer non-fatal injuries from these accidents. Most of these injuries and deaths occur at crosswalks, where the highway and pedestrians intersect. In this study, deep learning-based a new hybrid mobile CNN approaches are proposed to reduce injuries and deaths by automatically recognizing of crosswalks in autonomous vehicles. The first of these proposed approaches is the HMCNet approach, which is a hybrid model in which the MobileNetv3 and MNasNet CNN models are used together. This model achieves approximately 2% more accuracy than the peak performance of the lean used MobileNetv3 and MNasNet models. Another proposed approach is the FHMCNet approach, which increases the success of the HMCNet approach. In the FHMCNet approach, LSVC feature selection method and SVM classification method are used in addition to HMCNet. This approach increased the classification success of HMCNet by more than approximately 2%. Finally, the proposed FHMCNet offered approximately 3% more classification accuracy than state-of-the-art methods in the literature.
AtıfScopus10WoS7OpenAlex8İncele - MakaleYalnız künye2024Scopus SJRQ2Seasonal Monitoring of Heavy Metal Pollution in Water and Zebra Mussels Dreissena polymorpha as a Potential Bioindicator Species from Lake Habitat
Kutluyer Kocabaş, Filiz; Başaran, Ertuğrul; Kocabaş, Mehmet
In aquatic ecosystem, metal pollution is an important environmental hazard. Mussels as a bioindicator species are often used for assessment the presence of potentially toxic metals. Hence, the present study aimed to assess the effect of seasonal variations on some heavy metals (Cd, Cr, Pb, As, Zn and Cu) accumulation in water and Dreissena polymorpha from lake habitat. Our result indicated that Zn accumulated at a very high level in the zebra mussels while As accumulated at a high level in water samples. Seasonal variations significantly affected Cu concentration in the water samples (P < 0.05) while Cr concentration in the mussel samples was significantly affected by seasonal variations (P < 0.05). According to the water analysis, mean concentrations of metals are below the maximum limits established by the World Health Organization and USEPA, except As. Overall, our data emphasize anthropogenic pollution in the Turkish aquatic environment and confirm the use of D. polymorpha as a prospective biomonitor for metal polluted sites’.
AtıfScopus3WoS2OpenAlex4İncele - MakaleYalnız künye2024Scopus SJRQ3Development of a novel rare earth element doped chitosan-graft-poly(hydroxyethyl methacrylate) composite for biomedical applications: synthesis, characterization, drug delivery, and antibacterial properties
Gürler, N.; Torǧut, G.; Yazdıç, F.C.; Karaman, A.; Karaaslan Ayhan, N.
The films of chitosan-graft-poly(hydroxyethyl methacrylate) polymer (Ch—g-poly(HEMA)) doped with the rare earth element (REE) lanthanum (La content of 0, 0.2, 0.4, and 0.8 wt.%) were fabricated. The films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), thermogravimetric analysis (TGA), and powder X-ray diffraction (XRD) analysis. The films obtained were loaded with a model drug tetracycline by freezing/thawing method. The cumulative drug release properties of tetracycline were investigated. The release of tetracycline from the polymer matrix was carried out in phosphate-buffered saline (PBS) buffer (pH 7.4) at 37 °C. It was found that the REE-doped composite films had a retarding effect on tetracycline drug release compared to that of the undoped film. All tested composites regardless of the REE dopant content were found to be active against three Gram-positive and three Gram-negative bacterial strains used to assess the antimicrobial properties of the polymer composites. These findings demonstrated that lanthanum and tetracycline have a high affinity for the Ch—g-poly(HEMA) polymer and suggested a synergistic effect in the polymer—lanthanum—tetracycline system. The La3+-doped Ch—g-poly(HEMA) composite film can be used as drug carrier system in the biomedical field.
AtıfScopus4WoS4OpenAlex3İncele - MakaleYalnız künye2024Scopus SJRQ1Assessment of microplastic contamination in some commercial fishes of the southern Caspian Sea and its potential risks
Gholizadeh, Mohammad; Bagheri, Tahereh; Harsij, Mohammad; Danabas, Durali; Zakeri, Mohammad; Siddique, Mohammad Abdul Momin
This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45 °C for 72 h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were “Extreme danger” and “Danger” risk categories, respectively.
AtıfScopus29OpenAlex34İncele - MakaleYalnız künye2024Scopus SJRQ2Recycling Ti1.0Nb0.3Ta0.07Zr0.05 Conventional Alloys: Production of Non-equimolar TiZrCrNb0.3Ta0.07 Medium Entropy Alloys with the Addition of Cr for Improved In Vitro Corrosion Resistance
Guler, Omer; Say, Yakup; Dikici, Burak; Ozkul, Iskender; Niinomi, Mitsuo
A non-equimolar TiZrCrNb0.3Ta0.07 medium entropy alloy (MEA) was successfully designed as theoretical and produced by arc-melting method from Ti1.0Nb0.3Ta0.07Zr0.05 (TNTZ) scraps for possible usage in biomedical applications in this study. The main aim of this study is to find an alternative way to recycle with a reduced carbon footprint the available TNTZ conventional alloy and convert it to a value-added product during this recycling such as medium entropy alloys (MEAs) via using less energy. To examine the microstructural changes induced by the annealing process, scanning electron microscopy was employed. The chemical composition of the HEAs was assessed using energy-dispersive spectroscopy and x-ray photoelectron spectroscopy. Additionally, x-ray diffraction analysis was used to determine the crystallographic structure and phase composition of HEAs. Furthermore, in order to evaluate the electrochemical corrosion performance of the alloys, comprehensive in vitro corrosion tests were conducted in a simulated body fluid solution, specifically Hanks's Balanced Salt Solution. Some elemental segregation has been observed after the annealing process. A big migration of Zr and Cr elements was observed in the samples from the interdendritic region to the dendritic area during the annealing process. This segregation resulted in approximately 1.4 times increase in the hardness of the MEA. The electrochemical corrosion results showed that the in vitro resistance of the MEAs was higher than that of its conventional scraps.
AtıfScopus5OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ1Application of electrocoagulation process for the disposal of COD, NH3-N and turbidity from the intermediate sanitary landfill leachate
Ogedey, Aysenur; Oguz, Ensar
This study aims to determine the COD, NH3-N and turbidity disposal efficiencies from leachate in the Bingöl landfill and highlight the electrocoagulation (EC) process’s performance in removing these pollutants. After establishing that landfill leachate was intermediate aged, its characteristics were identified using physical, chemical and elemental analyses. Six parallel-connected electrode plates with stainless steel as the cathode and aluminium as the anode were used to construct an electrocoagulation cell. After a 40-min treatment interval, the optimal disposal efficiencies for COD and turbidity from the leachate were determined to be 87% and 62%, respectively, at pH 5. Following a 40-min reaction, BOD5 concentration and BOD5/COD ratio were determined to be 85.75 mg O2/L and 0.64, respectively, at pH 5. At a NaCl concentration of 10 mM, the optimum disposal efficiency for NH3-N was determined to be 33%. The reaction kinetics matched pseudo-first-order (PFO) kinetics due to high correlation coefficients (R2 = 0.93–0.99) in removing COD, NH3-N and turbidity under different experimental conditions. The optimal reaction rate constants were determined as 2.93 × 10−2 min−1, 1.92 × 10−2 min−1 and 7.3 × 10−3 min−1 for the disposal of COD, NH3-N and turbidity, respectively. Energy consumption, unit energy consumption and total consumption cost rose in the EC process when the current density was augmented from 15 to 25 mA/cm2.
AtıfScopus14WoS11OpenAlex12İncele - MakaleYalnız künye2024Scopus SJRQ1Sharma–Mittal holographic dark energy and scalar field in Bianchi type-I cosmology
Korunur, Sibel
In this work, we studied Sharma–Mittal holographic dark energy model by considering Bianchi type-I cosmology. For this purpose we analyzed equation of state parameter using IR cutoff scale. Also it is reconstructed correspondence between Sharma–Mittal holographic dark energy and tachyon and quintessence scalar fields. Finally, we created plots for the time-evolution of the equation of state, kinetic energy, and scalar potential.
AtıfScopus3WoS4OpenAlex4İncele - MakaleAçık Erişim2024Scopus SJRQ1A new chaotic system and its practical applications in substitution box and random number generator
Artuğer, Fırat; Özkaynak, Fatih
One of the successful practical applications of chaos theory and nonlinear dynamics is chaos-based cryptology studies. In this study, a new chaotic system is proposed. The proposed chaotic system generator model has a simple algorithmic structure. In addition to, generated chaotic systems have rich dynamics. It has been examined whether this system has potential advantages, especially for information security applications. As a result of the analysis and experimental studies, it is seen that the study makes many contributions to the literature. The simple mathematical generator structure has the potential to reduce computational complexity, which is an important problem for cryptology applications. One of the most comprehensive studies has been realized for chaos-based substitution box designs. 70,000 different substitution box structures have been generated. It has been known that the highest nonlinearity value that can be achieved for designs that transform chaotic system outputs into substitution box structures is 106.75 today. It has been shown that this value may be higher. The new highest nonlinearity value is calculated as 107. Side channel analysis has been examined for substitution box structures with the highest nonlinearity value among the substitution boxes generated in the study. Analysis results show that the proposed new substitution box structures may have an advantage for application-oriented attacks. Among the generated substitution box structures, 289 substitution box structures with a nonlinearity value of 106 and above are presented as a public dataset for researchers to use. In addition, 3 different random sequences with a length of 1 million-bit were produced with the proposed map, and the NIST SP 800–22 test was applied. Test results for all datasets were successful. In this way, the proposed map can also be used as a random number generator.
AtıfScopus13İncele - MakaleYalnız künye2024Scopus SJRQ2Dynamic Analysis and Metallographic Examination of Linings with Different Composite Contents used in the Brakes of a Hydraulic Turbine
Işık, Erdem; Kahraman, Gökhan
The main aim of this study was to find ways to increase the performance and life of generator brake linings, which can lead to cost reduction and adequate downtime periods for hydroelectric power plants. First, the dynamic analysis of the linings used in hydraulic turbines was realized and their reactions were examined under different operating conditions. Second, two types of brake linings with different composite components produced in the market were examined metallographically and tested to determine both the stopping performance and durability time of the turbine-generator unit for a sufficient period of time in the vertical 150-megawatt Francis turbine with approximately 500 tons of rotary weight. As a result of these experiments, the lining with the boron component led to much better results than the other brake linings. It has been determined that the boron-containing lining makes 100 stops more than the other lining and stops 20 s earlier in one stop. Therefore, the use of a composite lining with boron content in the braking systems of hydroelectric power plants significantly reduces maintenance incidents and operation costs as it prolongs brake replacement periods in these plants. Graphical Abstract: (Figure presented.)
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2024Scopus SJRQ1A new algorithm to generate aes-like substitution boxes based on sine cosine optimization algorithm
Artuğer, Fırat; Özkaynak, Fatih
Symmetric encryption approaches are generally used for data encryption. One of the basic requirements for symmetric encryption algorithms to provide security is strong s-box structures. Because s-box is a nonlinear unit in these encryption algorithms and provides the requirement called confusion. In this article, a new technique is developed to produce effective s-boxes like the 16*16 s-box structure used in the AES algorithm. In the proposed method, the sine cosine algorithm (SCA), one of the recently developed optimization algorithms, is used. SCA is a suitable option for generating strong s-boxes because of its strong randomness and ease of implementation. The proposed method first uses a logistic map to generate the initial population. Then, the nonlinearity value is optimized with the help of the sine cosine algorithm. The proposed method reaches the highest nonlinearity value (112) by relocating 126 values in the s-box structure produced initially. Looking at the results, it is seen that the proposed method gives better results than other optimization-based s-box creation methods. This new method has significant potential to improve the security of symmetric encryption algorithms and make data encryption processes stronger.
AtıfScopus19WoS22OpenAlex24İncele - MakaleYalnız künye2024Scopus SJRQ2Introducing the chemical potential of Cu–Mn–Al alloys for structural, electrical and thermal properties
Yüzüak, E.; Durak Yüzüak, G.
This study investigates the Martensite transition in Cu–Mn–Al alloys (CMAs) via the use of many methods, including scanning electron microscopy, temperature-dependent X-ray diffraction, resistivity and thermal measurements. The Martensite transition hysteresis and characteristic temperature are primarily determined by the alloy composition, crystal structure and residual stress. Furthermore, these alloys have been reported to have surface and crystallographic characteristics often associated with twinning structures. Resistivity experiments conducted during heating and cooling cycles demonstrate a 2.57-fold increase inside the phase change zone, emphasizing the influence of the transition on electrical conductivity. The Martensite transition temperature may be altered by 110 K by the manipulation of the electron-to-atom ratio (e/a), indicating the high susceptibility of this temperature to changes in chemical composition. Differential scanning calorimetry shows that the transition is accompanied by a maximum entropy shift of 48 J kg−1. K, which offers valuable information on the thermodynamic driving factors involved. This work successfully attains a cooling power of 1350 W, which is equivalent to the cooling power of NiTi wire (1500 W), by using a theoretical manufacturing method and optimizing the CMAs. Overall, this work clarifies the Martensite transition in CMAs, highlighting its impact on their characteristics and indicating their potential for effective thermal energy storage and release applications. It is advisable to further optimize their performance and economic viability by considering the e/a ratio.
AtıfScopus3WoS3OpenAlex4İncele - MakaleAçık Erişim2024Scopus SJRQ2Fabrication of CuAlVMg High-Temperature Shape Memory Alloy Containing Low-Soluble Vanadium Addition
Karaduman, Oktay; Boyrazli, Mustafa; Canbay, Canan Aksu; Özkul, İskender; Çelik, Emrah; Başbağ, Güneş
For the first time, CuAlVMg high-temperature shape memory alloy (HTSMA) with unprecedented alloy composition and with extended solubility of vanadium element was fabricated as-cast ingot by arc melting method, then homogenization of the alloy in high β-phase temperature region and quenching in iced-brine water were performed, respectively. The characteristic forward martensite to austenite martensitic transformation (MT) temperatures were detected at around 390 °C, which put the novel alloy in the category of HTSMAs. The thermal response of the alloy at high-temperatures was observed by DTA test as coherent with usual Cu-based HTSMAs. The residual sub-eutectoid precipitations emerging at around 500 °C hindered the direct martensitic transformation. The martensite structure of the alloy was revealed by XRD, SEM and optical microscopy tests.
- MakaleAçık Erişim2024Scopus SJRQ1The Mediating Effect of Experiential Avoidance on the relationship between psychological resilience and psychological needs in the COVID-19 pandemic
Dursun, Asiye; Kaplan, Yılmaz; Altunbaş, Tuğçe; Bahtiyar, Muhammed
The COVID-19 pandemic that has impinged upon the world affects individuals not only physically but also psychologically. Considering the effects of the pandemic that can be called a challenging life event, the concept of psychological resilience comes to mind. In this study, the effect of multidimensional avoidance on the relationship between psychological resilience and psychological need satisfaction-frustration of adults is discussed through structural equation modeling. The study data were collected online from 506 adults who participated voluntarily from 7 different geographical regions of Turkey. The study findings were obtained by using correlation analysis, structural equation modeling, and path analysis. As a result of the study, it is seen that all the variables of multidimensional avoidance except distraction/suppression and frustration directly affect psychological resilience in satisfaction and frustration of basic psychological needs. In addition, it shows that psychological resilience has a significant effect on satisfaction and frustration of basic psychological needs, both directly and indirectly through multidimensional avoidance.
AtıfScopus13WoS15OpenAlex13İncele - MakaleYalnız künye2024Scopus SJRQ2Synthesis, spectroscopic characterization and optical studies of poly(AN-co-St) composites with doped lanthanum (III) chloride for aerospace applications
Aydin, Handan; Torgut, Gülben
In this study, firstly, the copolymer of acrylonitrile (AN) and styrene (St) was synthesized by solution polymerization method using 2,2′-azobisisobutyronitrile (AIBN) as an initiator. The composites of copolymer incorporating lanthanum (III) chloride (3, 6, 9 and 18 wt%), the rare earth element (REE), were prepared and thin films were produced by thermal evaporation method for optical measurement. The samples were characterized by attenuated total reflectance Fourier transform infrared (ATR–FTIR), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) and X-ray diffraction (XRD). The glass transition temperature, which is one of the thermal properties of the synthesized copolymers and composites, was examined with a differential thermal analyzer. The changes in the optical properties of the samples produced with LaCl3 dopant were investigated using the UV–VIS spectroscopy. The optical band gaps of the samples were calculated using Tauc equation. As a result of the optical studies, it was observed that there was a change in the conductivity properties of the samples with the addition of LaCl3. The present results showed the advantage of using LaCl3 as a filler to improve the optical properties of poly(AN-co-St) samples.
- MakaleAçık Erişim2024Scopus SJRQ1Design of Ohmic Thawing Cell with Hydrostatic Pressure Units: Application in Minced Beef
Döner, Deniz; Çokgezme, Ömer Faruk; Çevik, Mutlu; İçier, Filiz
The thawing process is a common processing method used in the meat industry. To ensure provide food safety and protect meat quality, the thawing process should be carried out carefully. Ohmic thawing (OT) is one of the novel thawing methods. In this study, a custom-designed ohmic thawing prototype was set up and used to thaw frozen minced beef samples in different shapes (X: 13 × 4 × 3 cm3; Y: 13 × 6 × 2 cm3; Z: 13 cm height × 3.91 cm diameter) at 3 different voltage gradients (10–13-16 V/cm) by using 3 different electrode designs (E1, titanium foil; E2, needle type titanium electrode; E3, titanium embossed). The optimum OT condition resulting in a high-quality product with the highest process efficiency was determined. As an optimization procedure, a three-level general factorial design was performed. Thawing time, drip loss, thawing ratio, maximum temperature, ohmic power consumption, energy efficiency, and exergy efficiency values were used as responses. The cylindrical sample shape resulted in higher changes in quality and decreased performance of the process. The optimum ohmic thawing condition was a 16 V/cm voltage gradient for Y-shaped samples by using an E2 electrode design. The thawing time for the optimum condition was 2074s corresponding ohmic power consumption of 15.84 W. The drip loss during thawing was measured at 1.20%. The maximum temperature reached during the thawing process was recorded as 15.90 °C. Energy efficiency and exergy efficiency values were greater than 35%. Based on these results, the overall desirability of the ohmic thawing method was evaluated as 0.755. The obtained desirability value indicated the ohmic thawing method to be highly efficient and effective in achieving optimal thawing outcomes. The results of this study could give valuable information on the design of industrial-scale ohmic heating units to be used with solid foods, especially for thawing purposes.
AtıfScopus13WoS11İncele - MakaleYalnız künye2024Scopus SJRQ1Effect of Zr content on microstructure and wear behavior of Al-Si-Cu-Ni Mg-Zrx alloy
Taşgın, Yahya; Gök, Mehmet
In this study, the effect of zirconium addition (1, 1.5, 2 wt%) on the microstructural morphology and wear behavior of Al-Si-Cu-Ni-Mg alloys, known as light metals in which intermediate phases solidify rapidly at high temperatures, was investigated. The study aimed to obtain a stronger material by modifying the Al81Si12Cu4Ni2Mg alloy. It was observed that the Zr added to the alloy was homogeneously distributed throughout the samples. Aluminum and silicon formed compounds with zirconium (Al3Zr and ZrSi2), leading to the formation of a thinner and stronger structure. With the heat treatment applied to the aluminum alloys, the structure became more ductile. Additionally, as a result of Zr addition, microhardness increased, and wear values improved. Graphical abstract: (Figure presented.)
AtıfScopus2WoS2OpenAlex5İncele - MakaleYalnız künye2024Scopus SJRQ2Effects of Cr and W in TiMoNb Refractory High Entropy Alloys
Simsek, Tuncay; Kurtulus, Altug; Avar, Baris; Güler, Seval Hale; Dag, İlker Emin; Chattopadhyay, Arun K.
This study focuses on synthesizing and characterizing mechanically alloyed refractory high entropy alloys (RHEA) containing TiMoNb, Cr, W, and Cr + W. Analytical techniques including XRD, SEM, EDX, DTA, and TGA were employed to explore the influence of Cr and W on the alloys' structure, morphology, and thermal stability towards oxidation. XRD analysis confirmed the formation of a single-phase bcc solid solution in TiMoNbCr, TiMoNbW, and TiMoNbCrW alloys. Crystallite size decreased as milling progressed, yielding average sizes of approximately 7.2 nm, 7.4 nm, and 9.7 nm, with lattice strains of 1.143%, 1.148%, and 1.15%, respectively. Both experimental and calculated values of lattice parameters converged to around 3.1685 ± 0.002 and 3.1791 ± 0.010 Å for all three alloys. The synergy of Cr and W in TiMoNb was observed for the first time, impacting dislocation density, hardness, and oxidation stability. TiMoNbCrW exhibited reduced dislocation density and the highest hardness (502 HV). TGA indicated enhanced oxidation resistance up to 400 °C for TiMoNbCrW compared to the most vulnerable TiMoNbCr alloy.
AtıfScopus2OpenAlex2İncele - MakaleYalnız künye2024Scopus SJRQ2A Study on Comprehensive Production Parameters of Boron Nitride 2D Nanomaterial
Güler, Seval Hale; Safa, Hasan
In this study, BNNSs were synthesized via liquid-phase exfoliation method. Hexagonal boron nitride powders were used as the starting material. The production of boron nitride nanosheets was optimized. For this purpose, different sonication parameters and the effects of different solvents have been investigated. Different sonication power and time parameters of the homogenizer (Sonics Vibra-cell VCX, 750 W) used as the sonication parameter have been changed. In this stage, they were subjected to sonication process first for 1-1.5-2 hours at 25% sonication power, 1-1.5-2-4 hours at 50% sonication power, and 1-1.5-2-4-6-8 hours at 75% sonication power. As a result of particle size analysis, time/sonication power parameters were determined as 2 h-75%, 2 h-50%, 4 h-75%, 2 h-50%. The obtained samples were sedimented with centrifuge process, washed with distilled water to remove solvent, and dried. Different solvents were compared in the best power–time relationship. These solvents are dimethylformamide (DMF), isopropyl alcohol, N-methyl pyrrolidone, ethylene glycol. The best results were obtained in DMF. The synthesized BNNS samples were subjected to particle size (Malvern), scanning electron microscope (Zeiss, Gemini Supra 55), transmission electron microscope (Jeol Jem-1011), Fourier transform infrared spectroscopy (Thermo Scientific Nicolet™ iS™ 5), Raman (WITech alpha 300R), x-ray photoelectron spectroscopy (Specs-Flex), and x-ray diffraction analysis (PANalytical Empyrean).
- MakaleYalnız künye2024Scopus SJRQ1Investigation of Sexual Distress in Pregnant Women: A Turkish Multi-center Study
Koç, Emine; Baltacı, Nazlı; Yüksekol, Özlem Doğan; Gürel, Reyyan; Ulucan, Mihriban
Introduction: During pregnancy, sexual distress is common, but its prevalence and underlying factors require elucidation. This study was performed to investigate sexual distress in pregnant women. Methods: This research was designed as a descriptive and multi-center study. The study included 2365 pregnant women from 6 geographical regions of Turkey between April 1, 2022, and February 1, 2023. Data was collected using the “Pregnant Information Form” and “Female Sexual Distress Scale-Revised (FDS-R).” Descriptive statistics, independent sample t-test, analysis of variance, and the Pearson correlation test were used for data analysis. Results: Herein, 46.1% of pregnant women experienced sexual distress, and the mean FDS-R score of the study participants was 14.49. Participants who were dissatisfied with their sexual life before and during pregnancy (p < 0.001), those who did not have sexual intercourse during pregnancy (p < 0.001), those who experienced decreased sexual desire during pregnancy (p < 0.001), those who did not receive sexual education during pregnancy (p < 0.001), and those who experienced problems when engaging in sexual intercourse during pregnancy (p < 0.001) experienced more sexual distress. Sexual distress increased when the mean age and the number of pregnancies and children increased, whereas it decreased when the gestational week increased. Conclusions: Approximately half of the pregnant women included in the study experienced sexual distress. The findings highlight the importance of midwives and nurses encouraging pregnant women to discuss their sexuality. Policy implications: The findings of this study show that sexual distress during pregnancy is common and affected by some factors related to personal and sexual life during pregnancy. This result provides evidence of the need to develop culturally appropriate interventions and policies that include sexual partners in the context of improving pregnant women's sexual distress, sexual health, good family relationships and mental health.
AtıfScopus2WoS2OpenAlex2İncele